CN100520922C - Optical information recording medium - Google Patents

Optical information recording medium Download PDF

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Publication number
CN100520922C
CN100520922C CNB200610101645XA CN200610101645A CN100520922C CN 100520922 C CN100520922 C CN 100520922C CN B200610101645X A CNB200610101645X A CN B200610101645XA CN 200610101645 A CN200610101645 A CN 200610101645A CN 100520922 C CN100520922 C CN 100520922C
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China
Prior art keywords
information
substrate
layer
mentioned
recording medium
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CN1909073A (en
Inventor
西内健一
长田宪一
赤平信夫
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Abstract

In an optical information recording medium having at least two information layer, guide grooves for tracking or sample pits or information pits corresponding to information signals are formed on a surface of a first substrate. A first information layer formed by a thin film for reflecting a portion of a light beam made incident on the first substrate and permitting penetration of a portion of the light beam is formed on a surface of the first substrate. Guide grooves for tracking or information pits corresponding to information signals are formed on a surface of a second substrate. A second information layer having a reflectance higher than that of the first information layer is formed on a surface of the second substrate. Between the first information layer and the second information layer, there is formed a transparent separation layer for positioning the first information layer and the second information layer to be spaced a predetermined distance apart from each other.

Description

Optical data recording medium
The application is that application number is dividing an application of 2004100634963 patented claim.
Technical field
The present invention relates to utilize the light beam redisplaying information signal or the optical data recording medium of record and redisplaying information signal, the manufacture method of this medium and manufacturing installation, and the optical information recorder and the reproducer that use this medium, particularly relate to a kind of optical data recording medium with the sandwich construction that comprises a plurality of Information Levels, the manufacture method of this medium and manufacturing installation, and the optical information recorder and the reproducer that use this medium.
Technical background
Up to now, the optical data recording medium of forms such as CD, light-card occurred making, it can be realized the optical recording of information signal or reappear the information signal of record.Above-mentioned recording medium adopts semiconductor laser as light source usually.With the accurate light beam irradiates recording medium that focuses on of scioptics, just can on recording medium, write down the bulk information signal, and can reappear the information signal that is recorded on the recording medium.
How at present existing people further increases the recording capacity of this class recording medium in research.Be to improve density, effective measures are that critically confine optical beam is improved the resolution of reproduction.For this research of doing is to shorten the wavelength of light beam or enlarge numerical aperture (NA).Also the reproduction mode is made improvement in addition, improved the cross (talk) between focusing or tracking accuracy and the anti-stop signal, thereby improved the superficial density of record.
Although adopt said method that the recording capacity on the unit area is increased to some extent, when continuing to increase recording density, will be subjected to the restriction that only brings with the structure of a signal message layer recorded information.
If come recorded information with a plurality of Information Levels, the recording capacity of expection just can double.With U.S. Pat 5,126, No. 996 is example, the method for sandwich construction CD occurred making.
Below the process of above-mentioned CD is made in explanation.Shown in Figure 21 (a), on the substrate that has information track 211 surfaces of making, first information layer 212 is set with injection mo(u)lding or similar approach.Then, shown in Figure 21 (b), on stamper 213 upper surfaces, provide light-cured resin 214 with information track.Then, shown in Figure 21 (c), the surface of the first information layer 212 on the substrate 211 with information track and the surface with stamper 213 of information track are faced with each other.Under the state of substrate 211 pressurizeds, use up position irradiates light cured resin 214 then from stamper 213 outsides.Fix light-cured resin 214 like this, it is bonded on the first information layer 212.Then, shown in Figure 21 (d), remove stamper 213 down from light-cured resin 214.The result just can form to be had information track and constitutes resin bed by light-cured resin 214 on the surface.Then, shown in Figure 21 (e), on (making) resin bed, form second Information Level 215 by light-cured resin 214.At last, shown in Figure 21 (f), on second Information Level 215, form a protective finish 206.Just can obtain to have double-deck CD by above-mentioned operation.
Yet, when separating with light-cured resin 214, stamper 213 (sees Figure 21 (d)), above-mentioned habitual manufacture method may cause between first information layer 212 and substrate 211 or (being made by light-cured resin 214) resin bed separates easily.The dissatisfactory problem of processed finished products rate will appear like this.Cause the reason of this problem can be considered to bounding force between stamper 213 and (making) resin bed greater than between first information layer 212 and the substrate 211 or the bounding force between first information layer 212 and (making) resin bed by light-cured resin 214 by light-cured resin 214.
If substrate 211 is made of resin, the variation of environment temperature or humidity brings a problem sometimes, makes the CD of making distortion occur, or error occurs when reproducing signal.
In addition, because the influence of the light that an Information Level beyond target information layer reflects can make the device of redisplaying information signal from a plurality of Information Levels produce problem of unstable servo operation.
Summary of the invention
Starting point of the present invention is to overcome the problems referred to above that exist in the habitual structure, therefore the purpose of this invention is to provide a kind of manufacture method that is not easy the optical data recording medium with sandwich construction that is out of shape with environmental change, this recording medium, manufacturing installation and with the device of optical recording and redisplaying information.
To achieve these goals, one aspect of the present invention provides a kind of optical data recording medium with two different Information Levels, and can be from redisplaying information signal on the Information Level, recording information signal on Information Level, with light beam irradiates the time, can reappear the information signal of record, this optical data recording medium comprises: first substrate is provided with one or more guide grooves that are used to follow the tracks of and the sampling groove selected from the group that constitutes with the corresponding information track of information signal on the one side; Be located on arbitrary surface of first substrate and light beam had the first information layer of predetermined transmissivity and predefined reflectivity; Second substrate is provided with one or more guide grooves that are used to follow the tracks of and the sampling groove selected from the group that constitutes with the corresponding information track of information signal on the one side; Be located on arbitrary surface of second substrate and have second Information Level of predefined reflectivity; And be located at the separate layer transparent between the first information layer and second Information Level with respect to light beam.This structure of optical data recording medium provides a kind of dual-layer recording medium, can be from redisplaying information signal on first and second Information Levels, and recording information signal on first and second Information Levels, and reappear the information signal that writes down.
Preferably have such structure according to optical data recording medium of the present invention, promptly the thickness of the thickness of first substrate and second substrate is basic identical.The result of this structure is the structure that can form with respect to the separate layer vertical symmetry.Therefore, even the variation owing to temperature and so on produces effects such as stress in substrate when making optical data recording medium, distortion also can be compensated.Even have, also can prevent distortion and curling because the abnormal deformation factor that environment temperature or humidity change acts on two substrates.So just can obtain the structure of tenable environment variation lastingly.Therefore, promptly use resin to make first and second substrates, can prevent that still the distortion of the recording medium made from producing error when reproducing signal.
Preferably can satisfy following formula according to optical data recording medium of the present invention:
R1≈1-A1+(2×R2) -1
-{[1-A1+(2×R2) -1] 2-(1-A1) 2} 0.5
R1 wherein is the reflectivity of first information layer,
A1 is the absorptivity of first information layer, and
R2 is second Information Level with respect to being used for the reflectivity of light beam wavelength of redisplaying information.
Optical data recording medium preferably has such structure, and promptly the reflectivity of first information layer is 25% to 40%.Utilize above-mentioned this structure can obtain to have the recording medium of first and second Information Levels, first and second Information Levels are read-only Information Levels, wherein from the signal amplitude of first information layer and mutually the same from the signal amplitude of second Information Level, and the amplitude of reappearing is enough big.
Optical data recording medium of the present invention preferably has such structure, and promptly second Information Level comprises and is layered in the second on-chip reflection horizon, first dielectric materials layer, recording layer in order, and second dielectric materials layer.Information on second Information Level of Huo Deing can be rewritten according to this configuration.
Optical data recording medium of the present invention preferably has such structure, and promptly to have with respect to light beam be zero absorption coefficient to first information layer substantially.According to this configuration, can increase the luminous flux that arrives second Information Level.
Optical data recording medium of the present invention preferably has such structure, and promptly first information layer comprises double-layer films at least.According to this configuration, the reflectivity of first information layer can be increased, and the luminous flux that arrives second Information Level can be increased.In these cases, first information layer is comprised and be layered in first on-chip first dielectric materials layer, recording layer and second dielectric materials layer in order.Can obtain such first information layer according to this configuration, thereon can recorded information or rewrite information.
Optical data recording medium of the present invention preferably has such structure, promptly all has and the corresponding information track of information signal on a surface of first and second substrates.According to this configuration, can obtain jumbo recording medium.
Optical data recording medium of the present invention preferably has such structure, and promptly first information layer is read-only Information Level, and second Information Level is record and redisplaying information layer.According to this configuration, can be set at a low value to the absorptivity of the first read-only Information Level.In addition, owing to prevented the diffraction that information track causes, can write down or redisplaying information with low-power.
Optical data recording medium of the present invention preferably has such structure, and promptly the thickness of separate layer is greater than the depth of focus of the optical system of convergent beam, and less than pedestal tolerance that optical system allowed.According to this configuration, as long as the light beam of little error can be provided, just can reappear the information that does not have cross (talk) fully from another Information Level.
Optical data recording medium of the present invention preferably has such structure, and promptly information track or sampling groove are arranged on first and second substrates, and it is different with the shape that is located at the second on-chip groove to be located at the shape of the first on-chip groove.In these cases, preferably make be located at the second on-chip groove width greater than the width that is located at the first on-chip groove.According to this configuration, can make from the diffraction light of first information layer corresponding with diffraction light from second Information Level.Thereby reproducing signal stably.
Optical data recording medium of the present invention preferably has such structure, promptly forms guide groove in the surface of first and second substrates, and the width that is located at the guide groove in second substrate is greater than the width that is located at the guide groove in first substrate.According to this configuration, the effect of the guide groove in can making the effect that is located at the guide groove in first substrate and being located at second substrate is identical.
Optical data recording medium of the present invention preferably has such structure, promptly on the surface of first and second substrates, form information track, and be lower than the information track density that on the unit area of first substrate, forms in the density of the information track that forms on the per unit area of second substrate.According to this configuration, can reappear satisfactory information from the Information Level outside the depth of focus of the optical system of convergent beam.
Optical data recording medium of the present invention preferably has such structure, promptly in the surface of first and second substrates, form sampling groove or guide groove, and the gap ratio that is located at sampling groove in second substrate or guide groove to be located at the spacing of sampling groove in first substrate or guide groove big.Can obtain such recording medium according to this configuration, can reappear satisfied signal from the Information Level outside the depth of focus of the optical system of convergent beam, and tracer signal thereon.
Optical data recording medium of the present invention preferably has such structure, promptly on the surface of first and second substrates, form information track or sampling groove, and if from the incoming position of light beam, the direction of the information track between first substrate and second substrate is reciprocal.According to this configuration, the material of substrate can be identical with the production process of stamper with molding process.So only need to prepare two kinds of producing devices with identical function, or when making substrate a shared producing device.Thereby just can reduce the cost of substrate manufacturing process.
Optical data recording medium of the present invention preferably has such structure, promptly the information track, the guide groove that are located on first and second substrate surfaces, or the sampling groove is made spirality with respect to the core of first and second substrates, and, if from the incoming position of light beam, first on-chip spiral-shaped with second on-chip spiral-shaped be identical.According to this configuration, light beam is moving to the direction of outside or from the direction of external-to-internal internally, and is irrelevant with the Information Level of being followed the tracks of with information track.When adopting light beam to arrive the structure that moves the outside internally, can adopt such replay method, promptly detect management information, and the appointed information zone that comprises the part between the Information Level is conducted interviews in the inside of arbitrary Information Level.Therefore, we can say that above-mentioned structure is applicable to the recording medium that can carry out high speed access to Information Level.
Preferably adopt a pair of optical data recording medium of the present invention and an adhesive linkage, and second substrate of a pair of optical data recording medium is bonded to each other together by adhesive linkage.Can obtain to have the recording medium of four-layer structure according to this configuration, by just writing down and redisplaying information from the both sides irradiation at each Information Level with light beam.In these cases, preferably make the thickness of first substrate of a pair of optical data recording medium substantially the same, and make the thickness of second substrate of a pair of optical data recording medium also substantially the same.
According to another aspect of the present invention, a kind of method of making optical data recording medium is provided, this recording medium has two different Information Levels, and can be from redisplaying information signal on the Information Level, recording information signal on Information Level, and the information signal that with light beam irradiates the time, reappears record, the manufacture method of this optical data recording medium comprises: the first film forming step, on a substrate, form first information layer, on a side of substrate, be provided with one or more guide grooves that are used to follow the tracks of and the sampling groove from the group that constitutes with the corresponding information track of information signal, selected with predetermined transmissivity and predefined reflectivity; The second film forming step forms second Information Level with predefined reflectivity on second substrate, a side of second substrate is provided with one or more guide grooves that are used to follow the tracks of and the sampling groove of selecting from the group that constitutes with the corresponding information track of information signal; And the coating step, be coated in a resin bed transparent on the end face of the first information layer or second Information Level with respect to light beam; Bonding step faces with each other the first information layer and second Information Level and with resin bed first and second Information Levels is bonded to each other.According to the design of this optical data recording medium manufacture method, do not need to remove the step of stamper.Substrate with preformed information track is directly bonded together, just can obtain to have double-deck recording medium.Thereby can improve the yield rate of making.
Optical data recording medium manufacture method of the present invention preferably realizes such structure, and promptly the thickness of the thickness of first substrate and second substrate is basic identical.
Optical data recording medium manufacture method of the present invention also comprises a pressurization steps, from the outside of first and second substrates first and second substrates is pressurizeed.The resin bed of Xing Chenging does not have phenomenon in uneven thickness fully according to the method described above.
In optical data recording medium manufacture method of the present invention, preferably adopt light-cured resin to constitute resin bed, and from the position rayed resin bed in first substrate outside, thereby the fixing resin layer pressurizes in the outside of first and second substrates simultaneously.According to above-mentioned design, can form the resin bed that does not have phenomenon in uneven thickness fully at short notice.
Optical data recording medium manufacture method of the present invention also comprises a coating step, an adhesive linkage transparent with respect to light beam is coated on the end face of arbitrary second substrate in a pair of optical data recording medium that obtains with optical data recording medium manufacture method of the present invention; And a bonding step, this second substrate to optical data recording medium is faced with each other, and second substrate is bonded together with resin bed.According to the method described above, the bonding step that obtains the double-decker recording medium is repeated the recording medium that just can obtain four-layer structure for three times.That is to say,, just can make the recording medium of four-layer structure with the similar approach of making the double-decker recording medium as long as divided for three steps used identical manufacturing equipment.In these cases, preferably make the thickness of first substrate in a pair of optical data recording medium substantially the same, and make this thickness substantially the same second substrate in the optical data recording medium.
According to another aspect of the present invention, a kind of device of making optical data recording medium is provided, it comprises: the first substrate support parts are used to support first substrate; The second substrate support parts in the face of the first substrate support parts are provided with are used to support second substrate; A coated component is used for being coated with a resin bed on the end face of first substrate or second substrate; If pad in one plane, the first substrate support parts and the second substrate support parts face with each other on this plane, and this pad is provided with outwardly from first and second substrates; And a pressure-producing part, be used to the raise first substrate support parts or the second substrate support parts, and first or second substrate pressurizeed.Manufacturing installation with this optical data recording medium can be made the recording medium with sandwich construction effectively, and expection can improve recording capacity.
Optical data recording medium manufacturing installation of the present invention also comprises a light source, it is provided with facing to a surface of the first substrate support parts of contact first substrate, wherein makes a part of transmittance that the used material of the first substrate support parts allows light emitted.According to above-mentioned structure, adopted the light-cured resin layer, thereby can bond together first substrate and second substrate at short notice.
Optical data recording medium manufacturing installation of the present invention preferably has such structure, promptly, first and second substrates have a central opening in the middle, and the projection and the groove that have concentric or spiral on its arbitrary surface are listed as or guide groove, and, be used to make the information track row of first substrate and second substrate or the central axis of guide groove to coincide each other at least one first substrate support parts and the second substrate support parts provide a center correcting unit.According to said structure, can obtain such recording medium, can prevent from therein to be located at two on the information layer surface the information tracks row or the circular arc of guide groove deviation appears.
Optical data recording medium manufacturing installation of the present invention preferably further comprises first and second spindle units that are located at respectively on the first and second substrate support member center axis; And first and second internal guide elements that have a tapering separately, an end in tapering is greater than the central opening of substrate, and the other end is less than the central opening of substrate, and first and second internal guide elements can move along first and second spindle units.According to above-mentioned structure, contact respectively in the tapering of first and second internal guide elements under the state of central opening of first and second substrates, can be fixed on first and second substrates on the surface of the first and second substrate support parts.Therefore, the central axis of first information layer and the central axis of the first substrate support parts are coincide each other.In addition, according to degree the central axis of second Information Level and the central axis of the second substrate support parts are coincide each other near the mechanical precision restriction.In these cases, the front end that is preferably in one of the first axle part spare or the second axle part spare is provided with the conical part of a projection, and the tapering of the fluting of a correspondence is set at the front end of another spindle unit.According to above-mentioned structure, if move down the second substrate support parts, the conical part that is located at the projection of the first axle part spare or the second axle part spare front end will be engaged with each other with the tapering that is located at the fluting in another spindle unit front end.The central axis of first information layer and the central axis of second Information Level are coincide each other.
According to another aspect of the present invention, a kind of device with optical recording and redisplaying information is provided, this device optical data recording medium of rayed, recording medium has two different Information Levels, on Information Level, have one or more guide grooves that are used to follow the tracks of and the sampling groove from the group that the information track of corresponding informance signal constitutes, selected, thereby can be from redisplaying information signal on the Information Level, recording information signal on Information Level, and the information signal that reappears record.This device with optical recording and redisplaying information comprises: optical devices, with object lens the beam convergence of light emitted on recording medium; Be used to carry out the focus control device of control, the focus of light beam and arbitrary Information Level are coincide; The follow-up control apparatus of control bundle position makes light beam can follow information track, guide groove or sampling groove; Layer recognition device is used for signal of demodulation, according to the light of information track reflection or the light by the information track transmission comes the identifying information layer; Layer selecting arrangement is used to select an Information Level, redisplaying information signal from it, or recording information signal thereon; And switching device shifter, be used to switch the tracking mode of carrying out by follow-up control apparatus, with the selection result of carrying out in response to layer selecting arrangement.According to the optical information recorder and the reproducer of said structure, record and redisplaying information on the recording medium of sandwich construction can be had.
According to the device with optical recording and redisplaying information of the present invention, further comprise a layer comparison means, be used for the recognition result that the selection result of layer selecting arrangement execution and layer recognition device are carried out is compared, and focusing flip-flop circuit, be used to produce a pulse voltage, an output of corresponding comparison means is moved the focus of light beam between Information Level.According to above-mentioned structure,, just can move on to focal position on the target information layer if an Information Level is not the target that focuses on.In this case, preferably further provide a tracking polarity turning device, be used for synchronously switching the polarity of follow-up control apparatus with the operation that focuses on flip-flop circuit.According to above-mentioned structure, in recording medium with first information layer and second Information Level, even from the position of light beam incident see two-layer between information track be provided with by reverse direction, still can light beam be moved on on the information track of target information layer in moment.
Optical information recorder of the present invention and reproducer preferably have such structure, and promptly focus control device comprises: carry out first focus control device of control, make the focus of light beam identical with a position near Information Level; Second focus control device that permission is operated in than the first focus control device small range, and focus on switching device shifter; Be used for after the operation of first focus control device is finished, switching to second focus control device.According to above-mentioned structure, can stably carry out the servo operation of each Information Level, keep the focusing performance similar performance that can obtain simultaneously with habitual structure.
Optical information recorder of the present invention and reproducer preferably have such structure, be that focus control device has at least two kinds of modes of operation that are fit to each Information Level, focus control device is to arrange like this, and promptly the selection result of carrying out according to layer selecting arrangement is selected a kind of mode of operation.According to above-mentioned structure, focusing deviation can obtain proofreading and correct, thereby can write down satisfactorily or redisplaying information.
Optical information recorder of the present invention and reproducer preferably have such structure, be that follow-up control apparatus has at least two kinds of modes of operation that are fit to each Information Level, follow-up control apparatus is to arrange like this, and promptly the selection result of carrying out according to layer selecting arrangement is selected a kind of mode of operation.According to above-mentioned structure, tracing deviation can obtain proofreading and correct, thereby can write down satisfactorily or redisplaying information.
Optical information recorder of the present invention and reproducer preferably further comprise a photoelectric detector that is used to carry out focus control, it comprises first fen light receiving surface of a part of light that is used for the receiving record dieletric reflection, and being used to receive the second fen light receiving surface that is placed in the light that reflects on the same plane with first fen light receiving surface, second fen light receiving surface receives the light of the outer lateral reflection of first fen light receiving surface.According to above-mentioned structure, when redisplaying information from recording medium,, just can enlarge the scope of focusing by switching focusing sensing range between the moment of the moment of focusing and execution servo operation with sandwich construction.
Brief Description Of Drawings
Fig. 1 is a sectional view, represents the structure with optical data recording medium of two Information Levels of the present invention;
Fig. 2 is a skeleton view, represents the structure with optical data recording medium of two read-only Information Levels of the present invention;
Fig. 3 is a skeleton view, represents the structure with optical data recording medium of a read-only Information Level and record and redisplaying information layer of the present invention;
Fig. 4 is a skeleton view, represents the structure with optical data recording medium of two records and redisplaying information layer of the present invention;
Fig. 5 is a sectional view, represents the structure with optical data recording medium of four Information Levels of the present invention;
Fig. 6 is a schematic sectional view, represents the device that is used to make optical data recording medium of the present invention;
Fig. 7 is expression first partial section that is used to make the device of optical data recording medium of the present invention;
Fig. 8 is expression second partial section that is used to make the device of optical data recording medium of the present invention;
Fig. 9 represents the manufacturing sequence with optical data recording medium of two Information Levels of the present invention;
Figure 10 represents the manufacturing sequence with optical data recording medium of four Information Levels of the present invention;
Figure 11 is a block scheme, represents the structure of optical information recorder of the present invention and reproducer;
Figure 12 is a synoptic diagram, represents the optical sensor structure of optical information recorder of the present invention and reproducer;
Figure 13 is a synoptic diagram, represents the focus control part of optical information recorder of the present invention and reproducer;
Figure 14 is a curve map, represents the focus error signal waveform that can obtain from two Information Levels of optical data recording medium of the present invention;
Figure 15 is a synoptic diagram, the photoelectric detector of expression optical information recorder and reproducer;
Figure 16 is a synoptic diagram, represents the structure of the focus control part of optical information recorder of the present invention and reproducer;
Figure 17 is a synoptic diagram, represents the structure of the tracking Control part of optical information recorder of the present invention and reproducer;
Figure 18 is a sectional view, represents that another example of the present invention has the optical data recording medium of a read-only Information Level and record and redisplaying information layer;
Figure 19 is a sectional view, represents that another example of the present invention has the optical data recording medium of a read-only Information Level and record and redisplaying information layer;
Figure 20 is a sectional view, represents that an example more of the present invention has the optical data recording medium of two records and redisplaying information layer; And
Figure 21 represents the manufacture process of the optical data recording medium habitually practised.
Realize the best mode of invention
Below will be with reference to description of drawings optical data recording medium of the present invention and optical information recorder and reproducer.
Fig. 1 is a sectional view, the optical data recording medium of expression one embodiment of the invention.As shown in Figure 1, at thickness be the information track of the guide groove, sampling groove or the corresponding informance signal that are formed for following the tracks of on arbitrary surface of first substrate 1 of d1.Form the first information layer 2 that is made of film on the above-mentioned surface of first substrate 1, film is reflected into and is mapped to first on-chip a part of light beam 7, and allows a part of light beam 7 transmissions, and the thickness of film 2 is d2.It at thickness the information track that forms guide groove or corresponding informance signal on the surface of second substrate 3 of d3.Form second Information Level 4 that is made of film on the surface of second substrate 3, the reflectivity of this film is greater than the reflectivity of first information layer 2, and thickness is d4.Between the first information layer 2 and second Information Level 4, form transparent separate layer 5, be used for apart from d5 the first information layer 2 and second Information Level 4 being located apart from each other by predetermined.So just constituted and had double-deck optical data recording medium.
Best, first substrate 1 and second substrate 3 should constitute vertical symmetry with respect to separate layer 5 as much as possible.That is to say, preferably adopt substantially the same material and thickness (d1 and d3), and two the substrate differences each other figure that only is its lip-deep information track and the structure of first and second Information Levels 2 and 4.
If constitute optical data recording medium in a manner described, just can form structure with respect to separate layer 5 vertical symmetry.Therefore, even, still can compensate consequent any distortion during manufacture because factors such as temperature variation produce stress in substrate.Even the abnormal deformation factor that environment temperature or humidity change acts on two substrates, also can prevent distortion and curling.So just can obtain the structure of tenable environment variation lastingly.Therefore, promptly use resin to make first and second substrates 1 and 3, still can prevent to produce error when the reproducing signal because of there is distortion in the recording medium made.
Can be from the optical data recording medium of present embodiment by following mode redisplaying information signal, promptly with position irradiation two Information Levels (first and second Information Levels 2 and 4) of light beam 7 from first substrate outside, the variation of detection of reflected light beam value then, thus the information signal that to be recorded on first and second Information Levels reappeared.For energy redisplaying information signal, the light beam 7 of irradiation must be focused on each first and second Information Level 2 and 4 effectively.
Therefore, first information layer 2 must have predetermined reflectivity, so that can reappear the information signal that to be formed on the first information layer 2 along with catoptrical variation.In addition, in order to be used in light beam 7 arrival second Information Level 4 that shines and have predetermined strength, first information layer 2 must have predetermined transmissivity.Although second Information Level 4 does not need specific transmissivity,, second Information Level 4 must have big as far as possible reflectivity, so that the variation that the reflected light of information signal value is provided is amplified.This is because when reappearing the information signal of second Information Level 4, light beam 7 must penetrate first information layer 2 at twice.The reflectivity of second Information Level of therefore, setting in the structure of present embodiment 4 is higher than the reflectivity of first information layer 2.
About the material of first and second substrates 1 and 3, the material of employing is preferably in illumination beam 7 wavelength coverage interior focusings does not have tangible absorption, and intensity is very high.Therefore, first and second substrates 1 and 3 material are resins, polycarbonate resin for example, and polymethylmethacrylate (PMMA) resin, or the like, or glass.
If with the material of resin, can be heated to melting state to resin and it is poured in the mould that has information track or guide groove on the side, thereby form substrate as first and second substrates 1 and 3.If with the material of glass as first substrate 1 and second substrate 3, then adopt other method, for example promptly adopting on the surface of sheet glass, the form of etching method usefulness information track forms information.The another kind of method (light polymerization method) that substitutes is to be coated with one deck ultraviolet curable resin on surface of plate glass, then with the mould compacting that comprises information track on the surface, with the form formation information of information track.Yet the method that forms first and second substrates 1 and 3 is not limited only to above-mentioned method.As long as the method that adopts can provide the substrate with predetermined optical characteristic, also can adopt additive method.Because said method is the known method that adopts in the technology of making such as normal optical disk such as mini disks, has omitted more detailed description at this.
The function that depends on Information Level is read-only type or record and reproduction type, and the protuberance that forms on first and second substrates 1 and 3 surfaces and the figure of recess differ from one another.If Information Level is configured to read-only type, the form of protuberance and recess is exactly the information track row that are made of the figure that is formed on the substrate surface, and modulates according to information signal.If Information Level is configured to record and reproduction type, the form of protuberance and recess is exactly to carry out the guide groove of the tracking Control of light beam by continuous protuberance and recess being used to of constituting, or is fit to a kind of swinging chute that is called the tracking of ＂ sampling servo method ＂.
First and second substrates 1 preferably have identical size with 3, and make by same technology with same material.Specifically, if with the material of resin material as substrate, and form substrate with injection molding method, substrate distortion just may occur experiencing long-time back, and for example curling, this depends primarily on molded condition.In addition, the variation of environment temperature or humidity also may make substrate be out of shape significantly.If substrate forms with light polymerization method, although serious when the degree of distortion does not resemble with injection molding method, still similar distortion can appear.Consider These characteristics, present embodiment has such structure, promptly adopts similar technology to form first and second substrates 1 and 3, and with separate layer 5 two substrates is bonded together.Owing to adopted structure, can stop substrate to produce stress and distortion with respect to separate layer 5 vertical symmetry.So just can obtain the fully optical data recording medium of tenable environment variation.
The thickness that is used to obtain two substrates of substantially the same physical strength depends on the material of residing environment temperature of recording medium and substrate.In order to obtain the tolerance of two substrate thickness differences, made optical data recording medium: adopt the polycarbonate resin of 0.6mm thickness to form first substrate 1 with following structure.On first substrate 1, form the Au film of 10nm thickness then, thereby form first information layer 2.The thickness of second substrate 3 that is become by polycarbonate resin changes to the 1.2mm at 0.3mm, forms the Au film of 100nm thickness then, thereby forms second Information Level 4.In addition, with average thickness be the acrylic type ultraviolet curable resin layer formation separate layer 5 of 40 μ m.With separate layer 5 first information layer 2 and second Information Level 4 are bonded together.Deflection to the optical data recording medium of such manufacturing is measured, and has obtained the result of following numerical value.That is to say that if the thickness of second substrate 3 is 0.6mm ± 30% or littler, it is under the room temperature environment, temperature is 30 ℃, relative humidity (RH) is 80%, and after 1000 hours, the amount of curl of recording medium is below 0.4mm.Can realize stable servo operation in this case.Even make optical data recording medium bear worse environment, promptly under the relative humidity of 80 ℃ temperature and 80% through 1000 hours, if the thickness of second substrate 3 is 0.6mm ± 20% or littler, just can stop curling of recording medium.
Information Level is divided into two types on read-only type and record and reproduction type.Recording medium according to present embodiment has two Information Levels.Therefore, according to the order of the first information layer and second Information Level, recording medium can be one of following four types, i.e. (A) { read-only }-{ read-only }, (B) { read-only }-{ writing down and reproduction } (C) { write down and reproduction }-{ read-only }, and (D) { writes down and reproduction }-{ writing down and reproduction }.
Read-only Information Level is to be made of the film that forms on substrate surface, has above-mentioned information track on substrate, and film has predetermined reflectivity with respect to light beam.In these cases, material can be selected from following group, comprises metal in the group, Au for example, Al, Cu or their alloy; A kind of oxide, for example SiO 2, SiO, TiO 2, MgO or GeO 2A kind of nitride, for example Si 3N 4Or BN; A kind of dielectric material of sulfide, for example ZnS or PbS; These mixtures of material; And a kind of above-mentioned oxide, nitride and sulfide of sandwich construction.Use above-mentioned material can obtain the light beam of specific wavelength is had the Information Level of predefined reflectivity.
If first information layer 2 is read-only Information Levels, first information layer 2 must have predetermined transmissivity, makes the light beam 7 of first information layer 2 reflection incident from the position in first substrate, 1 outside, and allows the light beam of predetermined strength can arrive second Information Level 4.Making under the situation of the first information layer 2 and second Information Level 4,, just can realize above-mentioned target if make the thickness of first information layer 2 thinner than second Information Level 4 with identical materials.If make Information Level with metal, just metal being made thickness is the film of 5nm to 40nm.For reflectivity and the transmissivity that makes first information layer 2 all remains on high level, preferably make the absorptivity of Information Level low as far as possible.In these cases, first information layer 2 can be a kind of dielectric material or the organic material that can obtain high index of refraction and low absorption coefficient.In addition, if the layer that adopts dielectric material and organic material to build up, may obtain does not have the obviously Information Level of absorption to light yet.
If second Information Level 4 is read-only Information Levels, just needn't consider transmissivity.Reflectivity should be high as much as possible.If make second Information Level 4 with metal, just metal being made thickness is the film of 40nm to 200nm.
Record and reproduction type Information Level comprise and are formed on on-chip film to have guide groove or sampling groove on the substrate, and the optical characteristics of film changes when it absorbs the light beam of irradiation, and the state that changes can be discerned by light beam.For as the recording layer of Information Level, operational material can be selected from such group, and this group comprises a kind of phase-change material, its reflectivity owing to the variation of filminess along with the light that shines changes; A kind of magneto-optic memory technique of form of film, its direction of magnetization changes, and can detect this variation according to the Kerr effect; A kind of organic material for example has a kind of coloured material of the spectral reflectance factor of variation; And a kind of photochromics.
The crystalline phase of phase-change material can change between noncrystal and crystal, and this material can be selected from following group, comprises for example SbTe, InTe, GeTeSn, GeSbTe, SbSe, TeSeSb, SnTeSe, InSe, TeGeSnO, the sulfur family material of TeGeSnAu or TeGeSnSb section bar material; And Te-TeO for example 2, Te-TeO 2-Au, Te-TeO 2A kind of oxide material of types such as-Pd.
The crystalline phase of phase-change material can change between noncrystal and crystal, and this phase-change material can be a metallic compound, for example AgZn compound or InSb compound.
Magneto-optic memory technique can adopt MnBi, TbFe, or the material of TbFeCo type.
Toner can adopt colourless dyestuff, for example triphenylmethane.Photochromics can adopt the spiral pyrans, fulgide or azo group section bar material.
It is pointed out that recordable Information Level can be divided into the write-once type Information Level from its function, thereon can only disposable recording information, and the rewriting type Information Level, Ji Lu information can rewrite thereon.For the write-once type Information Level, only need on substrate, form a layer that constitutes by phase-change material layers or organic coloring material layer as Information Level.Can also adopt another kind of method, the double-decker that promptly adopts a light absorption film layer and metal level to constitute, the irradiation by light is prepared into alloy.
Although Information Level can only be made of a recording layer, preferably adopt to comprise two-layer at least sandwich construction, so that make the two-way variation of material energy that forms Information Level, and increase the optical change in the tracer signal.This double-decker can comprise the structure of dielectric materials layer/recording layer, comprises the structure in recording layer/reflection horizon, or comprises the structure (if from the incoming position of light beam 7, being according to above-mentioned order) of reflection horizon/recording layer.From the angle of substrate, three-decker can be the structure that comprises dielectric materials layer/recording layer/dielectric materials layer, or comprises the structure in dielectric materials layer/recording layer/reflection horizon.If from the incoming position of light beam 7, four-layer structure can be the structure that comprises dielectric materials layer/recording layer/dielectric materials layer/reflection horizon.From the angle of substrate, five-layer structure can be the structure that comprises first reflection horizon/dielectric materials layer/recording layer/dielectric materials layer/second reflection horizon.Contact if recording layer is formed each other with dielectric materials layer, when repeating record, just can prevent the deterioration of film.In addition, the optical change in can also higher degree ground setting recording information.
Dielectric materials layer can be made by a kind of material of selecting from following group, comprises a kind of oxide in the group, for example SiO 2, SiO, TiO 2, MgO or GeO 2A kind of nitride, for example Si 3N 4Or BN; A kind of sulfide, for example ZnS or PbS; And these mixtures of material.
Any material that the reflection horizon can be enumerated when above read-only Information Level being described constitutes.
In order to keep enough big light quantity on second Information Level 4, the material of making separate layer 5 does not preferably have tangible absorption to the light in light beam 7 wavelength coverages, particularly those has been passed through the light of first information layer 2.Therefore, separate layer 5 can be by transparent adhesives, and with the similar glass of substrate, or resin material is made.If make first and second substrates 1 and 3, preferably adopt the resin material of same type, so that after bonding, keep the reliability of machinery with resin material.To finish the required time of technique for sticking in order shortening, preferably to adopt ultraviolet curing resin.
Separate layer 5 be greater than the determined depth of focus of numerical aperture (NA) of object lens (6) and the wavelength (λ) of light beam 7 at least apart from d5, in case when reappearing some Information Levels from the reflection cross (talk) of another Information Level.If the center intensity (100%) the when intensity on the optical convergence point distributes in the concurrent mode with respect to light beam can reach more than 80%, depth of focus Δ z just satisfies following formula (1) approx:
Δz＝λ/{2(NA) 2} (1)
If λ=780nm, NA=0.55, then Δ z=1.3 μ m therefore, the zone of ± 1.3 μ m is included within the depth of focus.If adopt above-mentioned optical system, preferably the thickness d 5 of separate layer 5 is set in value greater than 2.6 μ m.
When light beam 7 focused on second Information Level 4, the meeting that influences of the record mark that comprises in the light beam that passes first information layer 2 caused cross (talk) when record second Information Level 4.Therefore,, preferably make the thickness d 5 of separate layer 5 be greater than depth of focus at least for reproducing signal stably, preferably five of depth of focus times.In common CD-ROM, the gap ratio depth of focus that is formed on the information track on the optical record medium will be lacked.If make the thickness of separate layer reach five times of depth of focus, the information track quantity on the first information layer 2 that is subjected to light beam 7 irradiations just can reach more than 25, this quantity than common for prevent that cross (talk) from allowing-26dB is much smaller.
In order on first and second Information Levels 2 and 4, to keep the high record density of information, first and second Information Levels 2 and 4 must be formed on object lens 6 can the scope of convergent beam within.That is to say that the thickness d 1 of first substrate 1 adds that the numerical value d1+d5 of thickness d 5 gained of separate layer 5 must be within the tolerance of the base thickness that optical system (object lens 6) allowed.
Therefore, the thickness d 5 that preferably makes separate layer 5 is greater than being used for the depth of focus of optical system of convergent beam 7, and less than pedestal tolerance that above-mentioned optical system allowed.If above-mentioned condition is met,, just can reappear the information that is not subjected to cross (talk) significantly from the Information Level outside the target information layer as long as the phenomenon of exceeding the bounds of light beam 7 is very little.It should be noted that the yield rate of considering the recording medium when producing optical data recording medium in enormous quantities, the phenomenon of exceeding the bounds of the thickness d 5 of separate layer 5 and light beam must be fixed on optimum value.If use above-mentioned material to form first and second substrates 1 and 3, first and second Information Levels 2 and 4 and separate layer 5, just can obtain a kind of like this recording medium, if from the position usefulness rayed Information Level 2 and 4 in first substrate, 1 outside, just can be from redisplaying information signal on Information Level 2 and 4.
A kind of structure that can stablize and reappear expediently the recording medium of signal from two Information Levels below will be described.To be recorded in two information signals on the Information Level for stable with reappearing expediently, also consider the simplification of reproducer structure simultaneously, preferably mutually the same from the signal level that two Information Levels obtain.Relate to a kind of like this structure in the following description, if from the position of light beam 7 incidents, the catoptrical value that obtains from the planar section of two Information Levels is mutually the same.For convenience of explanation, first and second Information Levels 2 and 4 in the described structure of instructions all are read-only Information Levels.Can ignore because the influence that the information track of first information layer 2 brings the diffraction of transmitted light in when explanation hypothesis.
Suppose that the reflectivity of first information layer 2 is R1, absorptivity is A1,, and the reflectivity of second Information Level 4 is R2.In these cases, also will do such hypothesis, promptly from the signal amplitude of two Information Levels when identical, the light quantity of the planar section reflection of two Information Levels also is identical.Above-mentioned situation is equivalent to such fact, promptly passes through incident, and has passed first information layer 2, and by the reflection of second Information Level 4, and then the reflectivity R1 of value T and first information layer 2 that passes the light beam 7 of first information layer 2 is identical.Satisfy the relation of following formulate in these cases:
R1≈T (2)
R1≈(1-A1-R1) 2×R2 (3)
R1≈1-A1+(2×R2)2
-{[1-A1+(2×R2) -1] 2-(1-A1) 2} 0.5 (4)
R1 is at R2=1, the maximal value that obtains during A1=0.In this case, R1 equals 0.382.If from the R2=0.9 of reality, the situation of A1=0.1, R1 equals 0.311.
Above-mentioned phenomenon explanation, if ignore the diffraction of light that passes first information layer 2, and first and second Information Levels 2 are identical with 4 pairs of catoptrical degree of diffraction, the reflectivity R2 of second Information Level 4 is 90%, the reflectivity R1 of first information layer 2 is 31%, and absorption coefficient A1 is 10%, and this structure just can make the amplitude of signal identical when redisplaying information from first and second Information Levels 2 and 4 information track.
The following practical structures that a kind of two Information Levels are described with reference to formula (2).Suppose that herein the amplitude of reappearing from two Information Levels can be considered to equate with interior in ± 20% scope.This hypothesis show the difference between formula (2) right side and the left side be in ± 20% in.
Therefore, if the amplitude of reappearing from first information layer 2 is littler by 20% than the amplitude of reappearing from second Information Level 4,, just can obtain the relation of representing with formula (5) with the above-mentioned relation formula (3) that replaces.On the other hand, if the amplitude of reappearing from first information layer 2 is bigger by 20% than the amplitude of reappearing from second Information Level 4, just satisfy following formula (6):
R1＝1.2×(1-A1-R1) 2×R 2 (5)
R1＝0.8×(1-A1-R1) 2×R 2 (6)
If Information Level is made by metal or dielectric material, when considering the actual characteristic of each layer, the reflectivity R2 of second Information Level 4 is within 70% to 90% the scope.In addition, the refractive index A1 of first information layer 2 is in be not more than within 20% the scope.With above-mentioned relation replace formula (5) and (6), the scope of the reflectivity R1 of first information layer 2 is 21% to 42%.In order to make first and second Information Levels 2 and 4 both sides keep big reproduction amplitude, preferably make the absorption coefficient A1 of first information layer 2 less.If the value of this absorption coefficient A1 is in below 10%, the scope of the reflectivity R1 of first information layer 2 is exactly 25% to 40%.
As mentioned above, if first and second Information Levels 2 and 4 all are read-only Information Levels, preferably make the scope of the reflectivity R1 of first information layer 2 be in 25% to 40%,, and keep big reproduction amplitude so that make from the reproduction amplitude of first and second Information Levels 2 and 4 similarly each other.
If second Information Level 4 is a record and redisplaying information layer, the reflectivity of Information Level is just less than the reflectivity of read-only Information Level.If the reflectivity of second Information Level 4 is 30%, and to adopt reflectivity be 19.5%, and absorption coefficient is 0% first information layer 2, with two Information Levels of rayed the time, is exactly identical towards the light quantity of object lens 6 reflections.Although in the following structure of also wanting declare record and reproducer, the amplitude of reproducing signal and the light quantity of reflection are that the difference between the pollution that is allowed according to recording medium and recording medium surface is predetermined.Therefore, if consider the precision of reproducing circuit and the stability of device, preferably make two difference between the reproducing signal amplitude less than 5 times.
The invention is characterized in, the substrate with preformed protuberance and recess is bonded together, thereby acquisition has the recording medium of two Information Levels.Therefore, the figure of the information track that need form on first substrate, 1 surface must have the signal shape that can reappear by the pedestal of first substrate 1.The signal shape that can be reproduced in the time of in addition, need must having on the surface by information track at the figure of the information track that forms on second substrate, 3 surfaces with rayed.Correspondingly, if from the position of light beam 7 incidents, first and second substrates 1 and 3 information track figure form towards same direction.If Information Level is read-only Information Level, the direction of information track figure comes to this, and promptly corresponding information signal forms information track on this direction.If Information Level is record and redisplaying information layer, just adopt above-mentioned structure to being used to manage the information addressing of guide groove.
Below will describe the structure of recording medium in detail, first and second Information Levels 2 and 4 wherein are read-only Information Levels, and read-only Information Level is divided into (A) class.
From reducing the angle of substrate cost of manufacture, preferably make first and second substrates 1 and 3 with identical as far as possible technology.The method that forms information track on substrate surface comprises stamper making step and injection mo(u)lding step that is used to make a stamper, therein resin material is injected the stamper that is contained in mould, thereby forms the substrate with information track.Because mastering is the known method that adopts usually when making mini disk or CD-ROM, has ignored the detailed description to this method.In brief, coat a kind of photoresist on sheet glass, use the surface according to the Ar laser beam irradiation photoresist of information signal modulation then, remove photoresist again, and then electroplate the surface of having removed photoresist, stamper has just been made.
If adopt same stamper manufacture craft, the shape of the information track that need on substrate, form, just the information track that is made of protuberance and recess uses the same method with respect to the relation on a plane and finishes.Fig. 2 (a) represents a routine optical data recording medium, and it is that the substrate made from a kind of technology is bonding to form by using.Shown in Fig. 2 (a), from the position of light beam 7 incidents, the information track 11 of first substrate 1 has convex shape.From the position of light beam 7 incidents, the information track 12 of second substrate 3 has concave.If the characteristic of photoresist differs from one another, if from the position of light beam 7 incidents, the information track of first substrate 1 has convex shape.From the position of light beam 7 incidents, the information track of second substrate 3 has concave.In any case from the position of light beam 7 incidents, the direction of the information track that forms in two Information Levels 2 and 4 is always reciprocal.
According to above-mentioned structure, can adopt identical materials and molding process and the same with the manufacture craft of stamper.Therefore, when making optical data recording medium, need prepare two kinds of producing devices, or need shared same device with said function.Therefore, can reduce the cost of production equipment.
From the position of light beam 7 incidents, be included in the information track that forms by reverse direction between two Information Levels 2 and 4 owing to have the recording medium of said structure, when adopting, between information track 2 and 4, must switch tracking polarity such as the tracking record of push-pull fashion or redisplaying information.For fear of this switching, from the position of light beam 7 incidents, the direction of the groove of second Information Level 4 needs the convex of changeabout.If the stamper with the photoresist with opposite characteristic is made second Information Level 4 according to the stamper manufacture craft, or use by conventional process and turn over one second stamper that the system stamper obtains once more, just can between two Information Levels 2 and 4, obtain to form rightabout groove.
The size of the information track of first and second substrates 1 and 3 below will be described.The size of the groove that forms on second substrate 3 is divided into two types, depends on whether the distance from the surface of first substrate 1 of light beam 7 incidents to first and second Information Levels 2 and 4 surfaces is within the base thickness tolerance Δ Wd that optical system allowed that is used for convergent beam 7.It may be noted that base thickness tolerance Δ Wd is that spherical aberration by light beam 7 decides, base thickness tolerance Δ Wd is inversely proportional to the biquadratic of the numerical aperture (NA) of object lens 6 (see figure 1)s substantially.For example, be 780nm a wavelength X, numerical aperture (NA) is that base thickness tolerance Δ Wd approximately is 50 μ m in 0.5 the optical system.Base thickness tolerance Δ Wd depends on the density of groove, the just interval between the groove.If the interval between the groove is long, even there is spherical aberration, still can reproducing signal.That is to say that the scope of tolerance is extended.
Structure shown in Fig. 2 (a) is to adopt under such condition, that is to say, from the surface of first substrate 1 of light beam 7 incidents to the distance on first and second Information Levels 2 and 4 surfaces within the base thickness tolerance Δ Wd that density allowed of optical system that is used for convergent beam and groove.The main foundation of above-mentioned condition is because the information track 11 on the first information layer 2 and second Information Level 4 differs from one another.Its reason is the main reflective surface that first information layer 2 has contact first substrate 1, and the main reflective surface of second Information Level 4 is between second Information Level 4 and separate layer 5.
If the width of each information track 11 on first substrate 1 is W11, the width of each information track 12 on second substrate 3 is W12, and the width of main reflective surface is such, for first information layer 2, this width is groove width W11, and for second Information Level 4, this width is groove width W13, and groove width W13 is the groove width between second Information Level 4 and separate layer 5.If adopt known sputtering method on substrate, to form Information Level, just can form on perpendicular to the direction of substrate surface and reach the film of information track, although vertical degree also depends on the method for making to end face.Therefore, littler than the groove width W12 of the information track 12 on second substrate 3 with respect to the groove width W13 on the interface of separate layer 5.For the diffraction of light degree that makes information track reflection is identical, the groove width W12 of the information track 12 on second substrate 3 must be greater than the groove width W11 of the information track 11 on first substrate 1.
The groove width W12 of the information track 12 on second substrate 3 relies on the actual technology that forms second Information Level 4 to proofread and correct.The inventor has done such experiment, adopts Au to constitute second Information Level 4 therein.Information track on second substrate 3 has the degree of depth of groove width W12 and the 90nm of 0.50 μ m separately, on information track, form an Au layer (second Information Level 4), the reflectivity of Au layer is more than 90%, thickness is 150nm, measure the shape of second Information Level 4 at this moment, this layer is equivalent to the interface of corresponding separate layer 5.The groove width W13 that measures is 0.3 μ m, and the degree of depth is 90nm.If form second Information Level 4 according to above-mentioned condition, the shape of the information track that forms on second substrate, 3 surfaces has just been determined, considers that groove width W12 is 0.70 μ m because the existence of second Information Level 4 can make the shape of groove change.In these cases, the groove width W11 of each information track that forms on first substrate 1 is 0.50 μ m, and the degree of depth is 90nm.As mentioned above, consider that the developed width of information track can dwindle owing to the thickness of second Information Level 4, can be in the size of the information track 12 that forms on second substrate 3 greater than the size of the information track on first substrate 1.It should be noted that the tracking interval T p1 of the information track that forms and the density of groove are identical on first and second substrates 1 and 3 surfaces.
In the stamper manufacturing process that is used to form second substrate 3, with on first substrate 1, adopting the mode of not deciding light source power the mode of resist exposure is compared, the size of information track has been enlarged slightly.Forming first and second substrates 1 is identical with 3 additive method.
Although be in the above description the groove width between first and second substrates 1 and 3 is made that than different sizes, the condition that forms Information Level produces such result sometimes, just different to the top surface inclination angle to the Information Level of the pitch angle of end face and formation of on-chip groove.In these cases, difference can occur between the degree of depth of the groove on the degree of depth of the groove on first substrate 1 and second substrate 3, or can make groove width and groove depth difference all occur.According to above-mentioned structure, can make between first and second Information Levels 2 and 4 catoptrical degree of diffraction closer to each other with respect to incident beam 7.Thereby can stably carry out signal reproduction.
The structure that Fig. 2 (b) is adopted when being illustrated in the base thickness tolerance that optical system that one of two Information Levels have surpassed convergent beam allows.The main cause of above-mentioned situation is the tolerance Δ Wd that Information Level has surpassed base thickness, and the light beam 7 that is focused on the Information Level can produce spherical aberration, thereby can not assemble luminous point fully.If shortened the wavelength of light beam 7 in order to increase the information density on the Information Level and enlarged the numerical aperture (NA) of object lens, because the tolerance Δ Wd of base thickness is reduced, the phenomenon of the base thickness tolerance Δ Wd that optical system that one of two Information Levels exceed converging light allows will appear.If the separate layer that can not obtain to approach when making separate layer 5, or the thickness low LCL of separate layer 5 above-mentioned phenomenon will occur when accurate.
In these cases, on-chip Information Level has surpassed the tolerance Δ Wd of base thickness, at this moment just needs to reduce the density of groove on the substrate surface, makes it be lower than the density with the on-chip groove that is in the Information Level within the base thickness tolerance Δ Wd scope.The structure of Fig. 2 (b) expression adopts under these circumstances, and promptly first information layer 2 is within the pedestal tolerance Δ Wd, and second Information Level 4 has surpassed base thickness tolerance Δ Wd.Each information track on first substrate 1 has predetermined groove width W11, and tracking spacing is Tp1, and the density of groove is Pd1.Each information track 14 on second substrate 3 has predetermined groove width W14, and tracking spacing is Tp3, and the density of groove is Pd3.If consider the aperture distortion that the spherical aberration of the light beam 7 on second Information Level 4 causes, the groove width groove width W14 of the information track 14 on second substrate 3 and tracking spacing Tp3 just should be greater than the groove width and the spacings of first substrate 1.
According to above-mentioned structure, even second Information Level 4 exceeds the base thickness tolerance Δ Wd that the optical system that is used for convergent beam 7 allows, the variation of the reflection light quantity that obtains from slot part still can be near the reflected light variable quantity that obtains from first information layer 2.Reproducing signal stably so just.
The information track on the tracking direction of substrate surface or the figure of guide groove below will be described.Although the information track that forms on first and second substrates 1 and 3 can constitute concentric circle, but, consider the precision of tracking spacing or the like, preferably resemble and adopt spiral groove the habitual CD, so just can on precision, improve to some extent than the concentric structure that adopts in the stamper manufacturing process.
First kind of structure is to arrange like this, and from the incident position of light, projection on first and second substrates 1 and 3 and groove are listed as towards same direction and arrange.In these cases, light beam is moving on the direction laterally of inboard or in a direction from the outside to the inboard, and is irrelevant with the Information Level at the information track place of being followed the tracks of.If adopt from the inboard structure of mobile beam laterally, just can use such reproduction mode, promptly detect management information, and find the inlet in appointed information zone in the inside of a certain Information Level, this information area comprises two positions between the Information Level.Therefore, this structure is applicable to the recording medium that needs high speed access.
Be used to realize that second substrate 3 of said structure can adopt above-mentioned method to make, turn over once more with stamper therein and make second stamper, so that make the direction upset of information track.That is to say, turn over and make second stamper, thereby form rightabout information track row, and obtain the opposite hand of spiral making the stamper surface with photoresist.By separate layer 5 bonding second substrate 3 and first substrates 1, just can obtain to have the recording medium of same-handed direction from the incoming position of light.
If omit the operation of making second stamper, will change the record direction that adopts in the stamper production process, thus first and second Information Levels 2 and 4 that acquisition has the same-handed direction from the incoming position of light.That is to say that when photoresist was exposed, the direction that the direction of making flat glass plate adopts during with the stamper of making first substrate 1 was opposite, thereby just can obtain to have first and second Information Levels 2 and 4 of same-handed direction from the light beam incoming position.Between first and second Information Levels 2 and 4, if from the incoming position of light, information track is reciprocal.
Second kind of structure is to arrange like this, and from the incoming position of light, projection on first and second substrates 1 and 3 and groove are listed as towards reverse direction to be arranged.In this case, with (direction from the inboard to the outside or the direction from the outside to the inboard) mobile beam consistently in the opposite direction of the Information Level with information track of being followed the tracks of.
Under the situation of continuous process information for a long time, said structure is effective.A kind of like this structure will be described herein, and light beam wherein is to move to the outside from the inside of information track on first information layer 2, and light beam is to move to inside from the outside of information track on second Information Level 4.When light beam after the outside of first information layer 2 reappears definite information, light beam is moved to the outside (that is to say that optical sensor is provided with the inlet of an information starting point on second Information Level 4, and keep same position) of second Information Level 4.Light beam begins in the outside of second Information Level 4 redisplaying information continuously.In above-mentioned information playback method, because light beam does not need the mobile optical sensor when a layer moves on to another layer, so can avoid elapsed time in the light beam moving process effectively.If track belongs to CLV pattern (clv mode), the position of optical sensor is exactly constant, therefore, can avoid change in rotational speed effectively.
As the mastering of second substrate 3 that is used for realizing above-mentioned surface, the method that can adopt is, the position opposite that adopt in exposure process during with the stamper of making first substrate 1 position that makes opening entry information.If the information of first substrate 1 is from the inner side opening entry, the exposure of stamper is from the outside.In first and second substrates 1 that obtain in this way and 3 recording mediums of making, comprise information track on first and second substrates 1 and 3, from the incoming position of light, these information tracks are to form by opposite direction, therefore, between Information Level, must change tracking polarity.
As the another kind of mastering of second substrate 3, outside exposure can be carried out according to the mode of similar above-mentioned situation under the following conditions, and the direction that the direction of making flat glass plate therein adopts during with the stamper of making first substrate 1 is opposite.In first and second substrates 1 that obtain in this way and 3 recording mediums of making, have information track on first and second substrates 1 and 3, from the incoming position of light, these information tracks are to form by identical direction, therefore, needn't between Information Level, change tracking polarity.
Said structure with read-only Information Level and record and redisplaying information layer below to be described, read-only-record and reproduction type structure (B) that these structures comprise, and record and reproduction-read-only type structure (C).
If compared with said structure (B) with (C), (B) is relatively good for structure, therein first information layer is made read-only Information Level, and second Information Level is made record and redisplaying information layer, because can reduce the light that first information layer absorbs like this.Under the situation of structure (C), first information layer is record and reproduction type Information Level, needs absorbing light on Information Level during recorded information.In this case, when signal was recorded on the first information layer 2, the light that is sent by record mark can produce diffraction.Therefore, the light quantity that can arrive second Information Level 4 has reduced.
Fig. 3 is a sectional view, expression have above-mentioned read-only-structure of a routine optical data recording medium of record and the structure (B) of reproduction type Information Level.As shown in Figure 3, on being the surface of first substrate 31 of d31, thickness forms the information track 38 of corresponding informance signal.In addition, formation has the first information layer 32 that predetermined transmissivity, predefined reflectivity and thickness are d32 on a surface of first substrate 31.Be to form on the surface of second substrate 33 of d33 to follow the tracks of guide groove 39 or sampling groove at thickness.Form second Information Level 34 that is made of film on a surface of second substrate 33, its thickness is d34, and its optical characteristics changes when being subjected to light beam 7 irradiations.Between the first information layer 32 and second Information Level 34, form a transparent separate layer 35, be used to make first information layer 32 and second Information Level, 34 location, make the two each other at a distance of predetermined apart from d35.
First information layer 32 has predetermined transmissivity with respect to light beam 7, so that make the luminous energy with predetermined strength arrive second Information Level 34.That a part of temperature of light beam 7 irradiations that strengthened on second Information Level 34 is raised.As a result, the optical characteristics of second Information Level 34 will change, thereby information is recorded on second Information Level 34.Therefore, the structure that second Information Level 34 has can satisfy simultaneously to the high absorption coefficient of light beam 7 and big optical change, thereby can reappear the signal of record effectively.
Because first information layer 32 is read-only Information Levels, has the information track 38 of corresponding informance signal on the surface of first substrate 31.Because second Information Level 34 is a record and reproduction type Information Level, has the guide groove that is used in recorded information time control light-beam position and follows the tracks of that constitutes by convex surface and concave part on the surface of second substrate 33, or the sampling groove (not shown) that constitutes by paired projection and groove, tracking directions that these projectioies and groove are operated towards the tracking of correspondence sampling-servo type are offset.If above-mentioned substrate is a dish, from the position of light beam 7 incidents, these information tracks, guide groove or sampling groove preferably are made into spirality on same direction.
Below will have the recording medium of above-mentioned (D) type structural information layer with reference to Fig. 4 explanation, this structure comprises two records and redisplaying information layer.As shown in Figure 4, thickness is that a surface of first substrate 41 of d41 is provided with and follows the tracks of guide groove 48 or sampling groove.Have the first information layer 42 that thickness is d42 on the surface of first substrate 41, it has predetermined transmissivity and reflectivity, and its optical characteristics can change when being subjected to light beam 7 irradiations.Be to form on the surface of second substrate 43 of d43 to follow the tracks of guide groove 49 or sampling groove at thickness.Forming the thickness that is made of film on a surface of second substrate 43 is second Information Level 44 of d44, and its optical characteristics can change when being subjected to light beam 7 irradiations.Between the first information layer 42 and second Information Level 44, form a transparent separate layer 45, be used to make first information layer 42 and second Information Level, 44 location, make the two each other at a distance of predetermined apart from d45.
In addition, in these cases, when the said structure on the substrate surface was used to the information track of read-only Information Level, this structure was effective.Particularly can with guide groove or sampling groove calculated address groove on substrate surface together,, thereby can enough all methods that are fit to the information track of above-mentioned read message come managing recording medium.
Be used for writing down the Information Level that the Information Level with redisplaying information can adopt said structure (B) to adopt, structure (B) is made of read-only Information Level and record and reproduction type Information Level.In these cases, first information layer 42 must have such characteristic, it can absorb the light beam 7 of scheduled volume, its state can change along with the rising of temperature, can from catoptrical variation, detect the state of its variation, and allow the light of scheduled volume to pass through, so that second Information Level 44 can be write down and redisplaying information.In addition, first information layer 42 must be kept such characteristic, promptly still allows the light transmission after recording of information is finished.Aforesaid first information layer 42 must be designed to like this, promptly should form a kind of film that can obtain high-quality signal, and should be able to reach the transmissivity of appointment before and after recording of information is finished.
The film that forms first information layer 42 has the variable optical constant that is similar to phase-change material, detects the state of its variation according to catoptrical variation.Writing down under the state of information on the first information layer 42, if with light beam irradiates second Information Level 44, a part of light by first information layer 42 will form diffraction.Remaining light beam is converged on second Information Level 44.Therefore, compare, must improve the intensity of light beam 7 with the beam intensity that offers read-only Information Level.
From the satisfaction of reproducing signal, the thickness of separate layer 45 must be greater than depth of focus, and preferably reaches more than five times of depth of focus.Like this, when light beam saw through first information layer 42, the quantity that is included in the record mark in the light beam was more than 25, just 5 square.Therefore can prevent the influence of effects such as cross (talk).
Be made at first information layer 42 under the situation of magnetooptic recording type film, its magnetized direction changes, and the light of transmission diffraction can not occur.Owing to can consider that like this transmitted light before information record and variation afterwards, has certain advantage.Yet for recorded information, first information layer 42 must absorb a certain amount of light.Therefore, compare, must increase light quantity with the light quantity that offers read-only Information Level.
Optical record medium has such characteristic, and promptly read-only type medium and record and reproduction type medium can coexist each other.Can also make the local ROM dish of a kind of what is called in addition, promptly on same medium face, have the record that is formed on inner read-only zones and is formed on its outside and reappear the zone.
A kind of recording medium with four Information Levels below will be described, it is to having convex surface and concave part on the surface and being bonded in the improvement of the recording medium that two substrates together constitute.Followingly this recording medium is described with reference to Fig. 5.
As shown in Figure 5, on a surface of first substrate 58, form the information track of corresponding informance signal or be used for the guide groove or the sampling groove of pencil tracing control.In addition, on a surface of first substrate 58, form first information layer 59, be used to be transmitted into a part of light beam 7 that is mapped on first substrate 58 with predefined reflectivity.On a surface of second substrate 60, form the information track of corresponding informance signal or be used for guide groove or the sampling groove that pencil tracing is controlled.Form second Information Level 61 on a surface of second substrate 60, its reflectivity is greater than first information layer 59.The first information layer 59 and second Information Level 61 are located relative to one another.Between the first information layer 59 and second Information Level 61, form at least one first separate layer 62.Have guide groove or the sampling groove that forms the information track of corresponding informance signal on the surface of the 3rd substrate 63 of same thickness or be used for pencil tracing control with first substrate 58.On a surface of the 3rd substrate 63, form the 3rd Information Level 64, be used to be transmitted into a part of light beam that is mapped on the 3rd substrate 63 with predefined reflectivity.Have guide groove or the sampling groove that forms the information track of corresponding informance signal on the surface of the 4th substrate 65 of same thickness or be used for pencil tracing control with second substrate 60.In addition, form the 4th Information Level 66 on a surface of the 4th substrate 65, its reflectivity is greater than the 3rd Information Level 64.The 3rd Information Level 64 and the 4th Information Level 66 are located relative to one another.It is identical with the thickness of first separate layer 62 to form the thickness of transparent second separate layer, 67, the second separate layers 67 according to the form of one deck at least between the 3rd Information Level 64 and the 4th Information Level 66.Make second substrate 60 and the 4th substrate 65 toward each other.Between second substrate 60 and the 4th substrate 65, form an adhesive linkage 68.
Because the recording medium of said structure has the structure of vertical symmetry with respect to adhesive linkage 68, can say for certain that even the variation of environment temperature and so on occurs, said structure is still stable.
The manufacturing method and apparatus of the recording medium with a plurality of Information Levels below will be described.
On two Information Levels, carry out when reappearing separately, if the interval between two Information Levels is too short, by the light of another Information Level reflection or the light that sees through this layer will produce cross (talk), therefore the influence that the reproducing signal amplitude changes can occur, or the distortion of servosignal occur.If the interval between two Information Levels is oversize, in the beam convergence point of a certain Information Level, will produce aberration.In order to prevent above-mentioned influence, the interval between two Information Levels must be constant.Need a point-device separate layer of thickness for this reason.In addition, two Information Levels must be bonded in together in such a way, make information track or sampling groove or the center of guide groove identical each other.Note that above explanation only is the recording medium at dish type, and be recorded information when recording medium is rotated.For recording medium with two Information Levels, must carry out tracking Control, to consider the degree of eccentricity that recording medium allowed simultaneously with an Information Level, and because second degree of eccentricity that the deviation of center causes between two Information Levels.The intent of the present invention is to prevent second degree of eccentricity, so that the tracking servo that the recording medium of the above-mentioned type is carried out compensates.
Consider the problems referred to above, the method for two substrates of a kind of manufacturing below will be described.It should be noted that first substrate forms with customary way.That is to say that first substrate is carried out injection mo(u)lding by the stamper making step and in a mould and obtained in the stamper production process.Second substrate can be made of the same procedure of making first substrate, or adopts such method, promptly repeats the stamper production process once more in order, thereby forms second stamper with reverse information track.The same processes that the injection mo(u)lding operation can adopt when making first stamper is carried out.The injection moulding machine that is used for present embodiment has the stamper that comprises spiral or concentric information track and guide groove, and its center accurately coincide with the center of the central opening forming machine that is used to form the first and second substrate center openings.Use this injection moulding machine can obtain first and second substrates, the center of substrate center opening and information track or guide groove do not have tangible deviation.
A kind of adhering device with bonding first and second substrates of separate layer with predetermined thickness below will be described.Fig. 6 is the schematic sectional view of this adhering device.As shown in Figure 6, adhering device comprises the upper support member 61 that is used to support second substrate 3; The lower support member 62 that comprises a light source 81 is used to support first substrate 1, and separate layer is solidified; Be used to promote the lifting piece 63 of upper support member 61; A resin supply nozzle 64 is used for providing the resin material 80 that forms separate layer to first substrate 1; And pedestal 65 that is used to support total system.
Upper support member 61 comprises and the plane of second substrate 3 contacted substrate support parts 66a, is used for fixing second substrate 3; A top base parts 66b is used for constituting between substrate support parts 66a and lifting piece 63 and is connected; From the outstanding upward axle 84 in the centre of substrate support parts 66a, has the cone tank that is used to proofread and correct lower support member 62 positioning relations at its front end downwards; And first internal guide elements 68 with a tapering, be used to regulate the position of second substrate 3.Be provided with spring 69 around last axle 84, it presses down first internal guide elements 68 with predetermined force.Form air entry 71 at substrate support parts 66a and second substrate, 3 contacted positions, adopt vacuum action to fix second substrate 3, air is discharged into an outside pump by the exhausr port 70 that is formed on substrate support parts 66a inside.
On the other hand, lower support member 62 comprises the base supports parts 72 that are used to support first substrate 1; A light-source box 73 is used for base supports parts 72 are fixed on pedestal 65, and holds light source 81; A lower shaft section 74 has a pyramidal projections of facing the groove of axle 84 at its front end; And second internal guide elements 75, utilize its taper position to regulate the position of first substrate 1.Be provided with spring 46 around lower shaft section 74, it is with pressing second internal guide elements 75 on the predetermined force.
Light source 81 solidifies resin material 80, so that form separate layer, it is set at the bottom of light-source box 73 and abuts against below the base supports parts 72.Therefore, base supports parts 72 are to make with the material that the light that allows light source 81 emissions passes through, for example glass or resin.In addition, base supports parts 72 contact with first substrate 1 that part ofly has an air entry 78, is used for fixing first substrate 1 by vacuum suction, thereby makes air be discharged into an outside pump by the exhausr port 77 that is located in the light-source box 73.From first substrate 1 towards above and be provided with a pad 79 that part of light-source box 73 facing to substrate support parts 66a, be used to keep the thickness d 5 of separate layer.
Resin supply nozzle 64 is discharged the resin material 80 that is provided by an external resin container tank by its front end, thereby resin material 80 is sprayed onto on the upper surface of first substrate 1.The front end of resin supply nozzle 64 moves on a circumference, and the radius of circumference approximately is with respect to 2/3 of first substrate, 1 radius of first substrate, 1 central shaft.Stopping when the upper surface of first substrate 1 provides resin material 80, just removing resin supply nozzle 64 from the zone of lower support member 62 tops.
Structure shown in Figure 7 represents to be used in the present embodiment obtain the device of predetermined thickness separate layer.Fig. 7 is a partial section, the state of the adhering device shown in the presentation graphs 6, and upper support member 61 wherein has been moved downward, and first substrate 1 and second substrate 3 have been bonded together by separate layer 5.In order to obtain the separate layer 5 that thickness is d5, the pad that to be provided with a thickness by the outer end of first and second substrates 1 and 3 be d79.The thickness d 79 of pad 79 must satisfy following formula:
d79＝d1+d3+d5 (7)
D1 wherein is the thickness of first substrate 1, and d3 is the thickness of second substrate 3.
For the inside in first and second substrates 1 and 3 provides thickness is the separate layer 5 of d5, and the length d 67 and the d74 of last axle 84 and lower shaft section 74 must satisfy following formula, suppose that the thickness of substrate support parts 66a is d65, and the thickness of light-source box 73 are d73:
d67+d74＝d65+d73+d1+d3+d5 (8)
By improving the precision of each parts, just can obtain internally to the outside separate layer 5 that does not have phenomenon in uneven thickness.
Referring to Fig. 6 and 8 structure that is used to carry out bonding operation is described, can prevents to produce degree of eccentricity between first and second Information Levels by this operation.The center of upper support member 61 and lower support member 62 is regulated by the tapering 83 in the groove of tapering 82 in the groove of last axle 84 and lower shaft 74.When upper support member 61 had been raised parts 63 and moves down, the center of upper support member 61 and lower support member 62 can be proofreaied and correct in the tapering 83 in the tapering 82 in the groove of last axle 84 and the groove of lower shaft 74.When two axles 67 and 74 horizontal plane position form when contacting each other in its lowest position, the centre deviation magnitude of upper support member 61 and lower support member 62 is within a few μ m, and this is to be determined by the mechanical precision of two axles 67 and 74.
For between first and second substrates 1 and 3 and on keep constant position relation between axle 84 and the lower shaft section 74, be provided with first and second internal guide elements 68 and 75, they touch the cylinder position of two axles 84 and 74, and have same central axis with axle 84 and 74.First and second internal guide elements 68 and 75 are made into taper, and diameter D68 of front end and D75 are respectively less than the diameter D3 and the D1 of the opening in substrate 3 and 1 separately for it, and the diameter D69 of its other end and D76 are respectively greater than the diameter D3 and the D1 of substrate 3 and 1.First and second internal guide elements 68 and 75 can move on the vertical direction of last axle 84 and lower shaft section 74 separately.Spring 69 and 76 is located at around two axles 84 and 74, and second substrate 3 to pressing down, and is upwards pushed away first substrate 1.As mentioned above, utilize injection moulding machine to form pinpoint have first and second substrates 1 of diameter D3 and D1 and 3 central opening.First and second substrates 1 and 3 central opening are received in the tapering of first and second internal guide elements 68 and 75.Hold substrate 1 and 3 by the air entry 71 and 78 that is located in substrate support parts 66a and 72.Under the contacted state of central opening of the tapering of first and second internal guide elements 68 and 75 and substrate 1 and 3, substrate 1 and 3 is fixed on the surface of substrate support parts 66a and 72.As a result, the central axis of the central axis of the Information Level of second substrate 3 and upper support member 61 coincide each other, and its precision is exactly mechanical precision basically.Equally, the central axis of the central axis of the Information Level of first substrate 1 and lower support member 62 coincide each other according to mechanical precision basically.If move down upper support member 61 under above-mentioned state, the central axis of the central axis of the Information Level that tapering 82 in the groove of last axle 84 and the tapering 83 in lower shaft 74 grooves will make first substrate 1 and the Information Level of second substrate 3 coincide each other.
The adhering device that utilization has said structure can obtain a kind of like this recording medium, can prevent from therein to be formed on two on the information layer surface information track, sampling groove or deviation appears in the circular arc of guide groove.
Following method of making optical data recording medium with two Information Levels with reference to the employing of the process description among Fig. 9 adhering device shown in Figure 6.
At first, shown in Fig. 9 (a), utilize sputter or vaporation method on first substrate 1, to form to allow a part of light beam transmission and have the first information layer 2 of predefined reflectivity, on the surface of first substrate 1, have the information track of corresponding informance signal or be used for the guide groove that pencil tracing is controlled, or have the sampling groove.Shown in Fig. 9 (b), on second substrate 3, form second Information Level 4 of reflectivity greater than first information layer 2 with sputter or vaporation method, on the surface of second substrate 3, have the information track of corresponding informance signal or be used for the guide groove that pencil tracing is controlled, or have the sampling groove, and its thickness and first substrate 1 are basic identical.Then first substrate 1 is fixed on the base supports parts 72.Subsequently, shown in Fig. 9 (c), provide photoresist resin material 80 to the upper surface of first information layer 2 with resin supply nozzle 64.Again second substrate 3 is placed on the base supports parts 66a, operate lifting piece 63 then, upper support member 61 is moved down, touch pad 79.With separate layer 5 second substrate 3 and first substrate 1 are bonded together according to certain intervals then, this is exactly the thickness d 5 (referring to Fig. 9 (d)) of separate layer 5 at interval.Shown in Fig. 9 (e), the outside surface with light source 81 emitted light beams 73 irradiations first substrate 1 solidifies resin material 80, has just formed separate layer 5 then.So just obtained to have the recording medium of two Information Levels 2 and 4.
Adopt said method, the operation that does not need to remove stamper just can obtain to have double-deck recording medium, and the substrate that is pre-formed information track from the teeth outwards can directly be bonded in together.So just can improve the yield rate of making.
Although be that resin material 80 is provided, also can on the upper surface of second Information Level 4, provide resin material 80 on the upper surface of first information layer 2 in said structure.
Following method of making optical data recording medium with four Information Levels with reference to the employing of the process description among Figure 10 adhering device shown in Figure 6.
At first, shown in Figure 10 (a), utilize sputter or vaporation method on first substrate 58, to form to allow transmission part light beam and have the first information layer 59 of predefined reflectivity, on the surface of first substrate 58, have the information track of corresponding informance signal or be used for the guide groove that pencil tracing is controlled, or have the sampling groove.
Shown in Figure 10 (b), on second substrate 60, form second Information Level 61 of reflectivity greater than first information layer 59, on the surface of second substrate 60, have the information track of corresponding informance signal or be used for the guide groove that pencil tracing is controlled, or have the sampling groove, and its thickness and first substrate 1 are basic identical.
Then first substrate 58 is fixed on the base supports parts 72.Subsequently, shown in Figure 10 (c), provide photoresist resin material 80 to the upper surface of first information layer 59 with resin supply nozzle 64.Again second substrate 60 is placed on the base supports parts 66a of adhering device, operate lifting piece 63 then, upper support member 61 is moved down, touch pad 79.With separate layer 62 second substrate 60 and first substrate 58 are bonded together according to certain intervals then, this is exactly the thickness d 62 of separate layer 62 at interval.With the outside surface of light source 81 emitted light beams 102 irradiations first substrate 58, resin material 80 is solidified then, just formed separate layer 62 (referring to Figure 10 (d)).So just obtained first recording medium 101, had two Information Levels in the one side.
Difference among said method and Fig. 9 is, be therein first and second substrates 1 and 3 with same thickness are bonded together, but in the present embodiment without limits with the thickness of bonding second substrate 60 of first substrate 58.In these cases, must change the thickness of pad 79 and the length of last lower shaft 84 and 74.
According to Figure 10 (a) to similar (referring to Figure 10 (e) to 10 (the h)) process of 10 (d), the 3rd substrate 63 and the 4th substrate 65 bonded together has just obtained to have on the surface second medium 103 of two Information Levels.To 10 (h), label 64 is represented the 3rd Information Level referring to Figure 10 (e), and 66 represent the 4th Information Level, and 67 represent second separate layer, and 104 representatives are from light source 81 emitted light beams.In these cases, preferably make first substrate 58 substantially the same with the thickness of the 3rd substrate 63.In addition, preferably make second substrate 60 substantially the same with the thickness of the 4th substrate 65.Form second with the 4th substrate 60 and 65 method can be with to form the first and the 3rd substrate 58 different with the method that adopted in 63 o'clock.In order to keep the thin substrate as recording medium, for example can adopting, light polymerization method makes the substrate attenuation.
Then, adopt and to be similar to adhering device shown in Figure 6 and to go up and form the second two-layer medium 103 and bond together forming first two-layer medium 101 and surface on the surface.At first, shown in Figure 10 (i), the photoresist resin is coated in the surface goes up on the upper surface of second substrate 60 that forms the first two-layer medium 101.Then, shown in Figure 10 (j), second substrate 60 and the 4th substrate 65 are bonded together, shine the outside surface of first substrate 58 with light source 81 emitted light beams 106 again, thereby resin material 105 is solidified, form adhesive linkage 68.Shown in Figure 10 (j), must change the length of pad 79 and the length of last lower shaft 84 and 74, make entire length, first and second separate layers 62 and 67 the length and the length of first to the 4th Information Level 59,61,64 and 66 of its corresponding record medium.When the exposure program of carrying out shown in Figure 10 (j), after seeing through first and second Information Levels 59 and 61, light source 81 emitted light beams 106 are radiated on the resin material 105.Therefore, with for example Fig. 9 (e), the exposure program shown in Figure 10 (d) or 10 (h) is compared, and the amount of light beam 106 needs to increase.
Have two-layer first and second recording mediums 101 and 103 separately when bonding together on the surface, the resin material 105 of use can adopt the resin that absorbs light beam.Also can use other resins except that the photoresist resin.For example can adopt a kind of heat reactive resin, hot-melt adhesive or other bonding agent.Therefore, the irradiation that in the operation shown in Figure 10 (j), can omit light beam.
When adopting said method, do not need to remove the operation of stamper.As long as in order each substrate that comprises preformed information track on the surface is bonded together, just can obtain to have the recording medium of four-layer structure, so just can improve the yield rate of making.Repeating three times, just can obtain to have the recording medium of four-layer structure for obtaining to have the required bonding process of double-deck recording medium.That is to say, use substantially the same manufacturing equipment just can make recording medium with four-layer structure.Required similar approach in the time of so just can adopting and obtain the double-decker recording medium.
Below to a kind of record and reproducer be described, be used for record and redisplaying information on the optical data recording medium of making according to the method described above of the present invention with reference to Figure 11.As shown in figure 11, the record of present embodiment and reproducer comprise a CD 111, and this is an optical data recording medium with a plurality of Information Levels; A spindle motor 112 that is used for rotating disc; The optical sensor parts 113 that are used for convergent beam, for example a kind of laser beam of light source 121 emissions; And five Circuits System that are used to control spindle motor 112 and optical sensor parts 113.First Circuits System is a light modulation system 114, is used for the light source 121 of operating optical sensing element 113.The second circuit system is the control system 115 that is used for the control bundle operation, and optical sensor parts 113 emitted light beams are focused on the CD 111, and is used for following the tracks of, and makes light beam follow information track or guide groove.The tertiary circuit system is a signal reproduction system 116, is used to read the information signal that is formed on the CD 111.Have at least one to have two or more setting state functions in above-mentioned three kinds of Circuits System, so that be optimum condition of each Information Level setting.The 4th Circuits System is a layer selective system 117, the state of three Circuits System of Information Level conversion at the light beam place that is used for detecting as required.The 5th Circuits System is a system control sytsem 118, is used to control the timing of four Circuits System.
The present invention has such structure, and the information that adopts layer selective system 117 to reappear record is selected the optimum condition of foregoing circuit system, and allowed recorded information on a plurality of Information Levels, also will prevent from simultaneously to make mistakes the information of reappearing from a plurality of Information Levels.
When redisplaying information signal from CD 111, be used for the rotation control unit 119 of rotating spindle motor 112 by system control sytsem 118 controls, thereby CD 111 is rotated according to constant speed.Represent a control signal of reproduction state to be provided for Laser Drive parts 120, thereby control the electric current that flows to light source 121 by following mode, i.e. instruction according to system control sytsem 118 is set at the performance number that is used to reappear to optical sensor parts 113 emitted light beams intensity.Pass optical system and object lens 122 of the optical sensor parts 113 that are located at the rear portion from light source 121 emitted light beams, make light beam become the light beam of convergence, be used for shining CD 111.
Pass the optical system of object lens 122 and optical sensor parts 113 once more by CD 111 beam reflected, thereby incide on the photoelectric detector 123, this photoelectric detector has a light receiving surface that is divided into several parts.The light beam of 123 pairs of incidents of photoelectric detector is carried out opto-electronic conversion, sends a signal to information playback system 116, the variation of the light quantity on corresponding each light receiving surface of its voltage.The signal that sends from photoelectric detector 123 is amplified by prime amplifier 124, with the position of the low frequency component control bundle in the signal.
Focus control parts 126 utilize a part of signal that sends from each light receiving surface of photoelectric detector 123 to obtain focus error signal, and use voice coil 125 of focus error signal operation.So just can control object lens 122, make it mobile slightly on respect to the vertical direction on CD 111 surfaces, make beam convergence on the information layer surface of CD 111.System control sytsem 118 sends a layer to layer selective system 117 and selects signal, is used for the Information Level that responsive control signal S03 specifies needs to focus on.Layer selective system 117 come switches light modulating system 114, control system 115 and signal reproduction system 116 according to this Information Level operation.So just can reappear the signal in the arbitrary Information Level that to be recorded in CD 111.
A layer identification component 132 demodulates layer identification signal from a signal from binary coding parts 130, thereby identifies the Information Level of focusing.If the Information Level that is focused is not a target information layer, one focuses on just mobile in order focal position in the middle of Information Level of flip-flop circuit 133.Focus on flip-flop circuit 133 pulse voltage is superimposed upon on the output signal of focus control parts 126, be used for instantaneous mobile voice coil 125 on vertical direction with respect to CD 111.So just can make beam convergence on target information layer.
Tracking control section 127 obtains a tracking control signal according to the combination of other output signals of photoelectric detector 123 in such a way, makes light beam follow information track or guide groove, and on the radial direction of CD 111 mobile slightly voice coil 125.When reappearing the Information Level of read-only type, in the middle of Information Level, switch tracking polarity with the command signal that a polarity upset device 128 sends according to layer selective system 117, so that employing differs method or the three beams method is carried out tracking by set mode, with the information track on the light beam redisplaying information layer.When reappearing the Information Level of record and reproduction type, in the middle of Information Level, switch tracking polarity or tracking with the instruction that polarity upset device 128 sends according to layer selective system 117.Like this,, just can reappear information track on record and the reproduction type Information Level, or be with the servo method redisplaying information groove of sampling under the situation about constituting by uneven groove at Information Level with the push-and-pull tracing if having guide groove on the Information Level.By switching tracking mode according to the type of Information Level, the recording density on two kinds of Information Levels can improve.
Follow the tracks of flip-flop circuit 129 for one pulse voltage is superimposed upon on the output signal of tracking control section 127, be used for instantaneous mobile voice coil 125 on the radial direction of CD 111.Light beam is moved on the surface of target trajectory.
According to the output signal of tracking control section 127, polarity upset device 128 is according to the direction that is formed on the information track on the Information Level its polarity of overturning, and is to follow the platform of guide groove or groove its polarity of overturning according to light beam.
If recording medium is to make with first and second substrates 1 and 3 of the same a kind of stamper production process manufacturing shown in Fig. 2 (a), if from the position of light beam 7 incidents, the direction of groove is exactly opposite between first and second Information Levels 2 and 4.If use above-mentioned two-layered medium, just use to focus on flip-flop circuit 133 mobile focal position between first and second Information Levels 2 and 4.Equally, between first and second Information Levels 2 and 4, switch tracking polarity with polarity upset device 128.So just can move to light beam on the information track of target information layer in moment.Therefore, when redisplaying information, can shorten the needed time of inlet of between Information Level, seeking with said method.
High fdrequency component in the signal that the binary coding parts 130 use prime amplifiers 124 of signal reproduction system 116 provide is come level and a datum of more above-mentioned signal, thereby conversion of signals is become binary coded signal.Binary coded signal is decoded according to the prearranged signal form by a demoder 131 then.So just can demodulate information signal from the record mark that is formed on the CD 111.The instruction of sending according to system control sytsem 118 is sent to an external unit to demodulated information S02 then.
Where necessary, be used to reappear or write down the state that is formed on the Information Level of specific region on the CD 111 and can come demodulation by layer identification component 132.Layer identification component 132 also has the function to the shape demodulation of Information Level or the like, and can identify Information Level.Preferably in the operation of making recording medium, write down above-mentioned information.The content of information comprises identifying information, is used to discern read-only Information Level and still writes down and the redisplaying information layer, or be used for the information of the difference between the control information layer characteristic.That is to say that these contents are about the optimum condition information with rayed each Information Level, carry out the optimum condition information of focus control or tracking Control, and to the optimum condition information of time of reproducing signal demodulation.
If information is recorded on a plurality of Information Levels, initial, the recorded information S01 that the information that system control sytsem 118 pilot light modulating systems 114 are write down by needs in the preset time reception constitutes.Light modulation system 114 converts tracer signal to the tracer signal with predetermined format with scrambler 134 earlier, the light intensity that Laser Drive parts 120 are launched from light source 121 according to the state modulation of wave setting device 135,135 pairs of pulse frequency divisions of wave setting device, or set the intensity of a variation.Light with modulate intensity is absorbed by the recording layer on the CD 111.So just can on the recording layer of CD 111, form reproducing mark, thereby finish recording of information.
Attention: wave setting device 135 has the best titime figure of executive logging on each Information Level, and synchronously changes its output with the output of layer selective system 117.Laser Drive parts 120 are modulated from the light intensity of light source 121 emissions according to the modulation waveform of corresponding each Information Level.
Utilize said structure can be in the best condition from a plurality of Information Levels the redisplaying information signal.In addition, recording information signal on a plurality of Information Levels, and the information that can reappear record in the best condition.
Below want the concrete working method of declare record and each parts of reproducer.
Figure 12 represents the structure of optical sensor parts.In the present embodiment, the type of focusing adopts knife edge method, and tracking mode adopts the push-and-pull method.
As shown in figure 12, the light of launching from light source 121 forms parallel light beam by a parallel lens 140, then by 141 reflections of a beam splitter.Beam reflected makes light beam irradiates on CD 111 by λ/4 plates 142 and object lens 122.The light that is reflected by CD 111 passes through object lens 122, λ/4 plates 142 and beam splitter 141, and again by lens 143, then, a part of light beam is reflected and incides and is used to carry out the photoelectric detector with a plurality of light receiving surfaces 145 of following the tracks of operation.The output of each light receiving surface of photoelectric detector 145 is amplified by prime amplifier 124, thereby obtains tracking error signal according to difference signal.
On the other hand, the be not reflected light of mirror 144 reflection incides the photoelectric detector with a plurality of light receiving surfaces 146 that is used to carry out focusing operation.The output of each light receiving surface of photoelectric detector 146 is amplified by prime amplifier 124, thereby obtains focus error signal according to difference signal.Referring to Figure 12, label 113 is represented optical sensor, and 120 represent the Laser Drive parts.
Figure 13 represents the part of focus control parts, is used for carrying out focus control according to the output of photoelectric detector.Although be to adopt photoelectric detector in habitual knife edge method with light receiving surface divided into two parts,, as shown in figure 13, the photoelectric detector 146 of present embodiment has quadrifid at least light receiving surface.The reason of doing like this is, if adopt photoelectric detector with light receiving surface divided into two parts, will run into the problem of servosignal distortion the operation that obtains servosignal from target information layer, this is because a part of light that is reflected by other Information Levels can incide on the photoelectric detector.Can prevent that servosignal from distorting although dwindle the area of the light receiving surface of photoelectric detector, another problem can occur, it is very limited that is exactly the scope that focuses on.
Therefore, the structure of present embodiment is that the light receiving surface of photoelectric detector 146 is divided at least four parts.Also adopted such method in addition, promptly in focusing stage and servo operation switching focusing sensing range between the stage.As shown in figure 13, the light receiving surface of photoelectric detector 146 is divided into light receiving surface 146a, 146b, 146c and 146d.Each light receiving surface 146a, 146b, the output of 146c and 146d is exaggerated device 147a respectively, 147b, 147c and 147d amplify, and obtain two kinds of focus error signal 148s and 149s by differential amplifier 148 and 149.Then by one of switching device shifter 150 selective focus error signal 148s and 149s.Selected focus error signal 148s (or 149s) is by focusing operation circuit 151 and focus on flip-flop circuit (seeing Figure 11), operational light electric transducer parts 113 (seeing Figure 11) then.
Followingly with reference to Figure 14 two kinds of focus error signals under the situation are described, a kind of situation is that another kind of situation is that photoelectric detector is divided into four parts a photoelectric detector separated into two parts that is used for focusing operation.The transverse axis representative focuses on orienting station, has marked the position of two Information Levels therein with L1 and L2.Figure 14 (a) expression light receiving surface is divided into two parts and the situation of light receiving surface when big.Figure 14 (b) expression light receiving surface is divided into two parts and light receiving surface situation hour.Figure 14 (c) expression light receiving surface is divided into four parts and adopts the situation of exterior light receiving plane 146a and 146d.Figure 14 (d) expression light receiving surface is divided into four parts and adopts the situation of interior lights receiving plane 146b and 146c.Be divided into two parts and adopt at the light receiving surface shown in Figure 14 (a) under the situation of photoelectric detector 151 with big light receiving surface, if focus is near the focused beam F1 from an Information Level, will incide on this light receiving surface from the folded light beam F2 of another Information Level.Focus error signal is distorted, and focus positioning error dF can occur.Be divided into two parts and adopt at the light receiving surface shown in Figure 14 (b) under the situation of photoelectric detector 152, can avoid receiving the light beam of leakage from another Information Level with less light receiving surface area.In addition, two focus error signals of curve of S shape on the position of corresponding informance layer position L1 and L2, can occur, so just can carry out servo operation.Yet it is littler than the scope of the drawing in M1 that the light receiving surface shown in Figure 14 (a) has under the larger area situation that scope M2 is drawn in actual focusing.Therefore, if recording medium occurs crooked or has irregular phenomenon in its surface, it is unstable that operation will become.
In order to address the above problem, present embodiment has adopted the quadrifid photoelectric detector 146 of light receiving surface.Light receiving surface is to form like this, folded light beam F1 from a certain Information Level is located substantially on light receiving surface 146a and the marginal center of 146b, and is located substantially on light receiving surface 146c and the marginal center of 146d from the folded light beam F2 of another Information Level.If the distance between the center of folded light beam F1 and F2 on the light receiving surface is Lf, and the size of folded light beam F1 and F2 each luminous point on light receiving surface is Ld, just the width 146w of outside light receiving surface 146a and 146d is set at greater than Lf and less than Lf+Ld.Figure 14 (c) is illustrated in light receiving surface is divided into four parts, and the focus error signal under the situation of use outside light receiving surface 146a and 146b.Because light receiving surface has left folded light beam F1 and F2 from two Information Levels, sigmoid curve will occur, situation about occurring when being similar to an Information Level.Carry out servo operation if respond above-mentioned signal, focal position just is positioned between the position L2 of the position L1 of an Information Level and another Information Level.In these cases, can obtain M3 on a large scale, as long as in this scope, can find focus signal.Figure 14 (d) is illustrated in light receiving surface is divided into four parts, and uses the focus error signal under the situation of inboard light receiving surface 146b and 146c.Focus error signal be similar to shown in Figure 14 (b) the light receiving surface separated into two parts, and the less situation of light receiving surface area.
Can realize that according to the photoelectric detector with quadrifid light receiving surface 146 of present embodiment big focusing draws in scope, and can be with respect to two stable focusing of Information Levels realization by switching the focus error signal shown in Figure 14 (c) and 14 (d).
When focus is drawn into, the differential signal 149s that switching device shifter 150 is selected from outside light receiving surface 146a and 146d, thus make the focusing operation circuit begin to carry out focusing operation.In this state, focus point is between two Information Levels.
When focusing operation circuit 151 was confirmed to have finished the operation of drawing in focusing, focusing operation circuit 151 just sent a focusing operation to switching device shifter 150 and finishes signal 151s.Finish signal 151s switching device shifter 150 in response to focusing operation and select differential signal 148s, it is the arbitrary inboard light receiving surface 146b of photoelectric detector 146 and the output signal of 146c, thereby arbitrary Information Level is carried out focusing.In preset range, carry out then and follow the tracks of operation, so that determine whether target information layer is focused on.If an Information Level seems to be focused on as yet, focus on flip-flop circuit 133 and just focal position is moved on on the target information layer.In said process, switching device shifter 150 is not carried out blocked operation.
Although above explanation is at adopting knife edge method as the structure of focus method, method of focusing is not limited in this.For example, also can adopt astigmatic method.If the employing astigmatic method just is provided with tubular object lens on the position of catoptron shown in Figure 12 144, and as shown in figure 15 a photoelectric detector 154 with the light receiving surface that is divided into eight parts is arranged near the photoelectric detector 146.Under the situation that adopts astigmatic method, near the light receiving surface 154a photoelectric detector 146,154b, similar when the use-pattern of the output of 154c and 154d and employing knife edge method.Draw in after operation finishes in focusing, use from the light receiving surface 154e in photoelectric detector 146 centres, 154f, the output of 154g and 154h, thus obtain focus error signal.
Utilize said structure, can stably carry out servo operation, keep the focusing that is obtained to habitual structure simultaneously and draw in the similar performance of performance each Information Level.
Quality with recording medium of a plurality of Information Levels depends on the scrambling of information track or guide groove shape.The record and the quality of reproducer depend on the distribution of parts sensitivity such as the distortion of beam intensity or photoelectric detector.Therefore, when carrying out servo operation, because the interference between the Information Level or the variation of spacer thickness can produce error voltage in focus error signal or tracking error signal.
In order to proofread and correct the error in focus control signal or the tracking control signal, when setting layer selective system 117 (seeing Figure 11), synchronously focus control parts and tracking control section are compensated adjusting.For example be fine compensation of focus control signal increase, thereby proofread and correct the tracing deviation that produces at interlayer.So just can in each Information Level, realize best beam convergence state.
Figure 16 represents the details of focus control parts.As shown in Figure 16, produce a focus error signal 160s by focus error detection circuit 160 bases from prime amplifier 124 (seeing Figure 12) and a signal relevant with focus control.Like this, focusing operation circuit 162 can obtain a focus control signal 126s by offset compensation circuit 161.Focus control signal 126s is sent to optical sensor parts 113 (seeing Figure 11), thus operating audio coil 125 (seeing Figure 11), and carry out focus control.
The structure of offset compensation circuit 161 can be according to a plurality of offset level of the signal sets that the outside provides.The offset setting device that is used to set the side-play amount that offers offset compensation circuit 161 comprises an offset setting device 163, is used for setting when the focusing operation of first information layer 2 finishes a side-play amount; And an offset setting device 164, be used for when the focusing operation of second Information Level 4 finishes, setting a side-play amount.The output 117s of skew selector switch 165 response layer selective systems 117 (seeing Figure 11), the side-play amount of one of transmission offset setting device 163 or offset setting device 164.
On the other hand, focusing operation circuit 162 receives the signal 161s that is sent by offset compensation circuit 161, and sends a focus control signal 126s, makes signal 161s vanishing, thus operating audio coil 125.The gain setting device that is used for the initialization circuit gain when carrying out focusing operation comprises a gain setting device 166, is used to set the gain at first information layer 2; And a gain setting device 167, be used to set gain at second Information Level 4.The output 117s of gain selecting arrangement 168 response layer selective systems 117 sends a signal from gain setting device 166 or gain setting device 167.Utilize said structure to set best focus state with respect to two Information Levels.
Aspect tracking Control,, just can carry out reproduction or record and reproduction process more satisfactorily if between Information Level, set optimum condition.Figure 17 represents the details of tracking control section.As shown in figure 17, obtain a tracking error signal 170s by tracking error testing circuit 170 according to a signal that relates to tracking Control among the output signal 124s from prime amplifier 124.Follow the tracks of function circuit 172 and can obtain a tracking control signal 127s by offset compensation circuit 171.Tracking control signal 127s is sent to optical sensor parts 113 by polarity upset device 128 (seeing Figure 11).Thereby operating audio coil 125 is carried out tracking Control.
The structure of offset compensation circuit 171 can be according to a plurality of offset level of the signal sets that the outside provides.The offset setting device that is used to set the side-play amount that offers offset compensation circuit 171 comprises an offset setting device 173, is used for setting when the focusing operation of first information layer 2 finishes a side-play amount; And an offset setting device 174, be used for when the focusing operation of second Information Level 4 finishes, setting a side-play amount.The output 117s of skew selector switch 175 response layer selective systems 117 (seeing Figure 11), the side-play amount of one of transmission offset setting device 173 or offset setting device 174.
On the other hand, follow the tracks of function circuit 172 and receive the signal 171s that sends by offset compensation circuit 171, and send a tracking control signal 127s, make signal 171s vanishing, thus operating audio coil 125.The gain setting device that is used to set gain when carry out following the tracks of operation comprises a gain setting device 176, is used to set the gain at first information layer 2; And a gain setting device 177, be used to set gain at second Information Level 4.The output 117s of gain selecting arrangement 178 response layer selective systems 117 sends a signal from gain setting device 176 or gain setting device 177.Utilize said structure to set best tracking mode with respect to two Information Levels.
In the structure of present embodiment,, be not limited in this structure although the information track that is formed on first substrate 1 has the shape of convex surface from the position of light beam incident.From the position of light beam incident, information track also can have the shape of concave surface.In this case, the direction of the information track on second substrate 3 is reversed, thereby makes recording medium can obtain the effect similar effects that is obtained with present embodiment.
Below want the concrete structure of descriptive information recording medium.
Example 1
The method for making of optical data recording medium shown in Figure 1 and the record and the reproduction process mode of optical data recording medium below will be described.
Adopt polycarbonate resin to form first and second substrates 1 and 3, and use and comprise on the surface that a mould of information track carries out injection mo(u)lding, so just made first and second substrates 1 and 3.The diameter of first substrate 1 is 120mm, and thickness is 1.2mm, and comprises the information track of arranging in the following manner in its surface, and the shortest slot length is 0.83 μ m, and groove depth is 100nm, and following the tracks of is 1.6 μ m at interval.The information track that is made of the groove row that form meets the EFM coding.Forming thickness with sputtering method on first substrate 1 is the Au layer of 10nm, thereby forms first information layer 2.
The diameter of second substrate 3 is identical with first substrate 1 with thickness, and second substrate 3 has the information track with first substrate, 1 same form.In order to make first and second substrates 1 have the identical hand of spiral with 3 incoming positions from light beam 7 after bonding, from the information track of second substrate 3 outwardly, the hand of spiral of projection and groove row is opposite with first substrate 1.Forming thickness with sputtering method is the Au layer of 10nm, thereby forms second Information Level 4.If from the position at information track place, first and second substrates 1 and 3 information track are concave shapes.
First substrate 1 is fixed on the substrate support parts 72 of adhering device shown in Figure 6, and the ultraviolet curable resin material 80 of acrylic compounds is provided on the upper surface of first information layer 2 with resin supply nozzle 64 then.Second substrate 3 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above second substrate 3 applied under the state of 5kg load rayed second substrate 3 with light source (UV-lamp) 81 emissions.Resin material 80 is solidified, and forming thickness between the first information layer 2 and second Information Level 4 is the separate layer 5 of d5.
Before execution is bonding, measure the thickness of inside line, middle part and the outside left of each substrate in advance, so that after bonding, calculate the difference of each several part.So just having obtained thickness is the separate layer 5 of d5.Like this, on each measuring position, separate layer 5 average thickness value are 65 μ m, and precision is below ± 8 μ m.The reflectivity of 2 pairs of 780nm wavelength of first information layer is that the reflectivity of 4 pairs of 780nm wavelength of 27.5%, the second Information Level is 91.6%.The grade of degree of eccentricity is 40 μ m between the Information Level.
Optical system has light source, the object lens of a suitable 1.2mm pedestal optimum thickness and one 0.5 the numerical aperture (NA) of the light of an emission 780nm wavelength, with this optical system redisplaying information on the aforementioned recording medium.Adopt knife edge method to carry out and focus on, adopt the push-and-pull method to carry out simultaneously and follow the tracks of.Focusing is to be carried out by photoelectric detector shown in Figure 13 146, and it has quadrifid light receiving surface, at the light receiving surface of drawing in switches light photodetector 146 between operation and the servo operation, thereby obtains a focus error signal.The reproducing beam that is used for reproducing signal has the power of 1mW.Its result can carry out stable focusing operation with respect to first and second Information Levels 2 and 4 really, and stably carries out to focus on and jump.It should be noted that the polarity that between Information Level, will switch tracking signal.From first and second Information Levels 2 and 4 reproducing signals that obtain, can observe good visual pattern.Shake to two signals is measured, and has obtained good result, and the signal jitter of first information layer 2 is 8.4% with respect to the standard deviation of detection window width, and the signal jitter standard deviation of second Information Level 4 is 8.7%.
Make the recording medium of gained bear damp and hot environment then, temperature is 80 ℃, and relative humidity is 80%, continues to carry out the contrast experiment after 100 hours.Signal is carried out similar assessment, consequently, stoped the variation of shape, can stably reappear, and when not considering to change, can obtain good jitter measurements.
Therefore, method of the present invention is a kind of effective ways of making many Information Levels recording medium.
Example 2
Below to illustrate and a kind ofly can form the more structure of the recording medium of high density information.Similar with example 1, adopt polycarbonate resin to form first and second substrates 1 and 3, and use and comprise on the surface that a mould of information track carries out injection mo(u)lding, so just made first and second substrates 1 and 3.The thickness of first substrate 1 is 0.58mm, and comprises the information track of arranging in the following manner in its surface, and the shortest slot length is 0.5 μ m, and groove depth is 90nm, and gauge is 0.8 μ m.Forming thickness with sputtering method on first substrate 1 is the Au layer of 11nm, thereby forms first information layer 2.
The thickness of second substrate 3 is identical with first substrate 1, and second substrate 3 has the information track with first substrate, 1 same form.For after bonding, make first and second substrates 1 with 3 from having the identical hand of spiral near the positions of light source, from the information track of second substrate 3 outwardly, the hand of spiral of projection and groove row is opposite with first substrate 1.Forming thickness with sputtering method is the Au layer of 10nm, thereby forms second Information Level 4.In order to make the shape of groove on its primary reflection surface identical with first substrate 1 after second Information Level 4 forms, in the middle of the groove that forms on the surface of second substrate 3, the shortest length of groove is confirmed as 0.6 μ m.Yet the interval of groove is identical with gauge with first substrate 1.
First substrate 1 is fixed on the substrate support parts 72 of adhering device shown in Figure 6, and the ultraviolet curable resin material 80 of acrylic compounds is provided on the upper surface of first information layer 2 with resin supply nozzle 64 then.Second substrate 3 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above second substrate 3 applied under the state of 8kg load rayed second substrate 3 with light source (UV-lamp) 81 emissions.Resin material 80 is solidified, and forming thickness between the first information layer 2 and second Information Level 4 is the separate layer 5 of d5.
Before execution is bonding, measure the thickness of inside line, middle part and the outside left of each substrate in advance, so that after bonding, calculate the difference of each several part.So just having obtained thickness is the separate layer 5 of d5.As a result, on each measuring position, separate layer 5 average thickness value are 52 μ m, and precision is below ± 5 μ m.The reflectivity of 2 pairs of 680nm wavelength of first information layer is that the reflectivity of 4 pairs of 680nm wavelength of 28.2%, the second Information Level is 89.6%.The grade of degree of eccentricity is 35 μ m between the Information Level.
Optical system has a light source, is used to launch the light of 680nm wavelength, the object lens of a best base thickness of suitable 0.6mm and one 0.6 numerical aperture (NA).Adopt with example 1 in identical servo method.Its result can carry out stable focusing operation with respect to first and second Information Levels 2 and 4 really, and the focusing of stably carrying out between the Information Level is jumped.It should be noted that the polarity that between Information Level, will switch tracking signal.From first and second Information Levels 2 and 4 reproducing signals that obtain, can observe good visual pattern.Shake to two signals is measured, and has obtained good result, under the situation of first information layer 2, be 7.6% with respect to the standard deviation of detection window width, and under the situation of second Information Level 4, standard deviation is 8.0%.
Make the recording medium of gained bear damp and hot environment then, temperature is 80 ℃, and relative humidity is 80%, continues to carry out the contrast experiment after 100 hours.Signal is compared calculating.Consequently, stop the variation of shape, can stably reappear, and when not considering to change, can obtain good jitter measurements.
Example 3
Below want the routine recording medium shown in the key diagram 5 with four Information Levels.Similar with example 1, adopt polycarbonate resin to form first to the 4th substrate 58,60,63 and 65, and comprise that a mould of information track carries out injection mo(u)lding, has so just made first to fourth substrate 58,60,63 and 65 on the use surface.The first and the 3rd substrate thickness separately is 0.58mm, and comprises the information track of arranging in the following manner in its surface, and the shortest slot length is 0.5 μ m, and groove depth is 90nm, and gauge is 0.8 μ m.Forming thickness with sputtering method respectively on the first and the 3rd substrate 58 and 63 is the Au layer of 11nm, thereby forms the first and the 3rd Information Level 59 and 64.
The second and the 4th substrate 60 and 65 thickness all are 0.4mm, and this thickness is littler than the thickness of the first and the 3rd substrate 58 and 63, so that reduce the integral thickness of the recording medium after bonding.Have on the second and the 4th substrate 60 and 65 surface separately and the first and the 3rd substrate 58 and 63 identical shaped information tracks.For after bonding, make first with the 3rd substrate 58 with 63 with the second and the 4th substrate 60 and 65 from having the identical hand of spiral near the positions of light source, the hand of spiral of the second and the 4th substrate 60 and 65 information track row is opposite with the first and the 3rd substrate 58 and 63.Forming thickness with sputtering method on the second and the 4th substrate 60 and 65 is the Au film of 10nm, thereby forms the second and the 4th Information Level 61 and 66.For second with the 4th Information Level 61 with make the shape of groove on its primary reflection surface identical after 66 form with the first and the 3rd substrate 58 and 63, in the middle of the groove that forms on the surface of the second and the 4th substrate 60 and 65, the shortest length of groove is confirmed as 0.6 μ m.
First substrate 58 is fixed on the substrate support parts 72 of adhering device shown in Figure 6.The ultraviolet curable resin material 80 of acrylic compounds is provided on the upper surface of first information layer 59 with resin supply nozzle 64.Second substrate 60 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above second substrate 60 applied under the state of 8kg load rayed second substrate 3 with light source (UV-lamp) 81 emissions, thereby resin material 80 is solidified.So just between the first information layer 59 and second Information Level 61, formed first separate layer 62.The 3rd substrate 63 is fixed on the substrate support parts 72 of adhering device.The ultraviolet curable resin material 80 of acrylic compounds is provided on the upper surface of the 3rd Information Level 64 with resin supply nozzle 64 then.The 4th substrate 65 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above the 4th substrate 65 applied under the state of 8kg load rayed second substrate 3 with light source (UV-lamp) 81 emissions, thereby resin material 80 is solidified.So just between the 3rd Information Level 64 and the 4th Information Level 66, formed second separate layer 67.
Before execution is bonding, measure the thickness of inside line, middle part and outside left respectively, so that after bonding, calculate the difference of each several part.So just obtained the thickness of first and second separate layers 62 and 67, first and second separate layers 62 and 67 average thickness are respectively 50 μ m and 53 μ m.In the precision on each measuring position within ± 7 μ m.In this case, the first and the 3rd Information Level 59 and 64 is that the reflectivity of the 28.5%, the second and the 4th Information Level 61 and 66 pairs of 680nm wavelength is 88.7% to the reflectivity of 680nm wavelength separately.The grade that has degree of eccentricity between first and second media 101 and 103 of two Information Levels separately has desirable numerical value, is respectively 30 μ m and 28 μ m.Then, first medium 101 is fixed on the substrate support parts 72 of adhering device.The ultraviolet curable resin material 105 of acrylic compounds is provided on the upper surface of second substrate 60 of first medium with resin supply nozzle 64.Second medium 103 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above second medium 103 applied under the state of 10kg load enhancing light beam 106 irradiations second medium 103 with light source 81 emissions, thereby resin material 105 is solidified.So just first medium 101 and second medium 103 have been bonded at together by adhesive linkage 68.
The mode that adopts the optical system of redisplaying information and servo method and the example 2 from this recording medium is similar.When lip-deep two Information Levels execution from the first and the 3rd substrate 58 and 63 reappeared, its result can realize stable focusing operation really.In addition, the focusing between the Information Level is jumped and also can stably be carried out.In from the reproducing signal of arbitrary Information Level, can observe good visual pattern.Shake is separately measured to first to fourth Information Level 59,61,64 and 66, has obtained good result, and is very desirable with respect to the standard deviation of detection window width, is respectively 7.9%, 8.3%, 7.9% and 8.2%.
Make this recording medium bear damp and hot environment then, temperature is 80 ℃, and relative humidity is 80%, continues to carry out the contrast experiment after 100 hours.Signal is compared calculating.Consequently, stoped the variation of shape, redisplaying information stably, and when not considering to change, can record good jitter measurements.
Example 4
Concrete structure and the record and the reproduction process mode of optical data recording medium shown in Figure 180 below will be described.
First substrate, 31 usefulness polycarbonate resins are made, and have the information track according to the corresponding informance signal of EFM modulation in its surface.The thickness d 1 of first substrate 31 is 0.58mm, and diameter is 120mm.Be formed on first substrate, 31 lip-deep information tracks and arrange that in the following manner promptly the shortest slot length is 0.44 μ m, groove depth is 90nm, and gauge is 0.74 μ m.Forming thickness with sputtering method on first substrate, 31 surfaces is the ZnS layer of 40nm, constitutes first information layer 32.
Second substrate, 33 usefulness polycarbonate resins are made, and have the guide groove that is used to follow the tracks of light beam in its surface.The thickness d 1 of second substrate 33 is 0.58mm, and diameter is 120mm.That be formed on its lip-deep guide groove is 1.48 μ m at interval, and the guide groove width is its at interval half, and the degree of depth is 70nm.On second substrate, 33 surfaces, form the reflection horizon 180, the ZnS-SiO that make with Al of stack in order 2 Dielectric materials layer 181, Ge-Sb-Te register rete 182, and ZnS-SiO 2Dielectric materials layer 183.So just constituted second Information Level 34.
First substrate 31 is fixed on the substrate support parts 72 of adhering device shown in Figure 6.On the upper surface of first information layer 32, provide ultraviolet curing resin material 80 with resin supply nozzle 64.Second substrate 33 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above second substrate 33 applied under the state of load rayed second substrate 33 with light source (UV-lamp) 81 emissions.Resin material 80 is solidified, between the first information layer 32 and second Information Level 34, form separate layer 35.The average thickness of separate layer 35 is 40 μ m, be in the precision on each measuring position ± 8 μ m within.Thickness d 1 that it should be noted that first substrate 31 is 0.6mm, and this is the optimum thickness that is used for the object lens pedestal of convergent beam 7.This structure is to determine in the following way, makes optimum be in the center of separate layer 35.In these cases, the reflectivity of 32 pairs of 680nm wavelength of first information layer is 10%, and the reflectivity of 34 pairs of 680nm wavelength of second Information Level is 17%.
With an optical system record and the redisplaying information of aforementioned recording medium are measured, optical system comprises object lens that are used to launch the light source of 680nm wavelength light beam and have 0.6 numerical aperture (NA) that is fit to best base thickness 0.6mm, and mensuration is to carry out according to the linear velocity of 6m/s.When measured signal, the power of reproducing beam is 1mW.So just can stably carry out focusing operation with respect to first and second Information Levels 32 and 34.In addition, the focusing between the Information Level is jumped and also can stably be carried out.Aspect tracking, first information layer 32 is used suitable phase differential method of reappearing the information track of arrow gauge, second Information Level 34 is used the push-and-pull method that is fit to guide groove.In from the reproducing signal of first information layer 32, can observe good visual pattern.The result that the shake of each mark is measured is to obtain the deviation of standard with respect to the detection window width that is used for 8.4% coded signal.
The shortest mark lengths is that the EFM signal of 0.6 μ m is recorded in platform portion and the slot part on second Information Level 34.Light-struck result from modulating between the deletion power of the recording power that adopts 5mW and 10mW can observe good visual pattern.The amplitude of longest mark 11T is similar to the amplitude that obtains from first information layer 32.The measurement that shake is carried out has obtained good result, and the value that records in platform portion is 9.7%, and the value that records at slot part is 9.5%.Above-mentioned information signal can rewrite repeatedly.The above-mentioned characteristic of it should be noted that from substrate inside to visual observation equates.
In an experiment, make this recording medium bear damp and hot environment, temperature is 80 ℃, relative humidity is 80%, continues to carry out comparative determination after 100 hours.Consequently, stoped the variation of shape, redisplaying information stably, and when not considering to change, can record good jitter measurements.
Therefore we can say that said method is a kind of effective ways of making many Information Levels recording medium.
Example 5
The concrete structure of optical data recording medium shown in Figure 19 and the record and the mode of operation of redisplaying information thereon below will be described.
First substrate, 31 usefulness polycarbonate resins are made, and have the information track according to the corresponding informance signal of EFM modulation in its surface.The thickness d 1 of first substrate 31 is 0.58mm, and diameter is 120mm.Be formed on first substrate, 31 lip-deep information tracks and arrange that in the following manner promptly the shortest slot length is 0.44 μ m, groove depth is 90nm, and gauge is 0.74 μ m.Forming thickness with sputtering method in order on first substrate, 31 surfaces is the ZnS-SiO of 40nm 2 Dielectric materials layer 194, thickness are the SiO of 30nm 2Dielectric layer, and thickness is the ZnS-SiO of 140nm 2Dielectric materials layer 196.So just constituted first information layer 32.
Second substrate, 33 usefulness polycarbonate resins are made, and have the guide groove that is used to follow the tracks of light beam.The thickness d 1 of second substrate 33 is 0.58mm, and diameter is 120mm.That be formed on second substrate, 33 lip-deep guide grooves is 1.1 μ m at interval, and channel depths is 50nm.The thickness made from Au that forms stack in order on second substrate, 33 surfaces is the reflection horizon 198 of 50nm, and thickness is the ZnS-SiO of 50nm 2 Dielectric materials layer 198, thickness are the Ge-Sb-Te register rete 199 of 10nm, and thickness is the ZnS-SiO of 20nm 2 Dielectric materials layer 200, and be the translucent reflective layer 201 of 14nm with the thickness that Au makes.So just constituted second Information Level 34.
First substrate 31 is fixed on the substrate support parts 72 of adhering device shown in Figure 6.On the upper surface of first information layer 32, provide ultraviolet curing resin material 80 with resin supply nozzle 64.Second substrate 33 is placed on the base supports parts 66a of adhering device.Operate lifting piece 63 then, upper support member 61 is moved down, make it touch pad 79.From above second substrate 33 applied under the state of load rayed second substrate 33 with light source (UV-lamp) 81 emissions.Resin material 80 is solidified, between the first information layer 32 and second Information Level 34, form separate layer 35.The average thickness of separate layer 35 is 43 μ m, be in the precision on each measuring position ± 9 μ m within.Thickness that it should be noted that each substrate is 0.58mm.The object lens 6 that are used for convergent beam 7 are fit to the optimum thickness 0.6mm of pedestal.This structure is to determine in the following way, makes optimum be in the center of separate layer 35.In these cases, the reflectivity of 32 pairs of 680nm wavelength of first information layer is 17%, and the reflectivity of 34 pairs of 680nm wavelength of second Information Level is 45%.
With an optical system record and the redisplaying information of aforementioned recording medium are measured, optical system comprises object lens that are used to launch the light source of 680nm wavelength light beam and have 0.6 numerical aperture (NA) that is fit to best base thickness 0.6mm, and mensuration is to carry out according to the linear velocity of 1.3m/s.When measured signal, the power of reproducing beam is 1mW.So just can stably carry out focusing operation with respect to first and second Information Levels 32 and 34.In addition, the focusing between the Information Level is jumped and also can stably be carried out.Aspect tracking, first information layer 32 is used the phase differential method, second Information Level 34 is used the push-and-pull method.In from the reproducing signal of first information layer 32, can observe good visual pattern.The result that the shake of each mark is measured is to obtain the deviation of standard with respect to the detection window width that is used for 8.1% coded signal.
The shortest mark lengths is that the EFM signal of 0.6 μ m is recorded in platform portion and the slot part on second Information Level 34.Light-struck result from modulating between the deletion power of the recording power that adopts 19mW and 9mW can observe good visual pattern.The amplitude of longest mark 11T is similar to the amplitude that obtains from first information layer 32.The shake result who records is 8.3%.Above-mentioned information signal can rewrite repeatedly.The above-mentioned characteristic of it should be noted that from substrate inside to visual observation equates.
In an experiment, make this recording medium bear damp and hot environment, temperature is 80 ℃, relative humidity is 80%, continues after 100 hours signal to be carried out comparative determination.Consequently, stoped the variation of shape, redisplaying information stably, and when not considering to change, can record good jitter measurements.
Example 6
The concrete structure of optical data recording medium shown in Figure 20 and the record and the mode of operation of redisplaying information thereon below will be described.
First substrate, 41 usefulness polycarbonate resins are made, and have the guide groove that is used to follow the tracks of light beam in its surface.The thickness of first substrate 41 is 0.58mm, and diameter is 120mm.That be formed on first substrate, 41 lip-deep guide grooves is 1.48 μ m at interval, and the width of groove is half of gauge, and the degree of depth of groove is 0.50nm.Forming thickness with sputtering method in order on first substrate, 41 surfaces is the ZnS-SiO of 110nm 2 Dielectric materials layer 201, thickness are the Ge of 10nm 2Sb 2 Te5 register rete 202, and thickness is the ZnS-SiO of 80nm 2Dielectric materials layer 203.So just constituted the first information layer 42 that can write repeatedly.
Second substrate, 43 usefulness polycarbonate resins are made, and have the guide groove that is used to follow the tracks of light beam in its surface.The thickness of second substrate 43 is 0.58mm, and diameter is 120mm.That be formed on second substrate, 43 lip-deep guide grooves is 1.48 μ m at interval, and the width of groove is half of gauge, and channel depths is 50nm.The thickness made from Al that forms stack in order on second substrate, 43 surfaces is the reflection horizon 204 of 100nm, and thickness is the ZnS-SiO of 18nm 2 Dielectric materials layer 205, thickness are the Ge of 25nm 2Sb 2 Te5 register rete 206, and thickness is the ZnS-SiO of 110nm 2Dielectric materials layer 207.So just constituted second Information Level 34.
First substrate 41 is fixed on the substrate support parts 72 of adhering device shown in Figure 6.On the upper surface of first information layer 42, provide ultraviolet curing resin material 80 with resin supply nozzle 64.Second substrate 43 is placed on the base supports parts 66a of adhering device.Operation lifting piece 63 moves down upper support member 61, makes it touch pad 79.From above second substrate 43 applied under the state of load rayed second substrate 33 with light source (UV-lamp) 81 emissions.Resin material 80 is solidified, between the first information layer 42 and second Information Level 44, form separate layer 45.The average thickness of separate layer 45 is 40 μ m, be in the precision on each measuring position ± 7 μ m within.Thickness d 1 that it should be noted that first substrate 41 adopts 0.6mm, and this thickness is the best base thickness that is used for the object lens 6 of convergent beam 7.Determine a displacement, make optimum be in the center of separate layer 45.Under non-recording status, the reflectivity of first information layer 42 is 19%, and transmissivity is 40%, and the reflectivity of second Information Level 44 is 17%.
With an optical system record and the redisplaying information of aforementioned recording medium are measured, optical system comprises object lens that are used to launch the light source of 680nm wavelength light beam and have 0.6 numerical aperture (NA) that is fit to best base thickness 0.6mm, and mensuration is to carry out according to the linear velocity of 6m/s.When measured signal, the power of reproducing beam is 1mW.So just can stably carry out focusing operation with respect to first and second Information Levels 42 and 44.In addition, the focusing between the Information Level is jumped and also can stably be carried out.
The shortest mark lengths is platform portion and the slot part that the EFM signal of 0.6 μ m is recorded in the guide groove of first information layer 42.When adopting the 14mW recording power, can observe good visual pattern.The amplitude of longest mark 11T is similar to the amplitude that obtains from first information layer 42.The shake result who records has good numerical value, is 10.8% in platform portion, is 11.3% at slot part.
The shortest mark lengths is platform portion and the slot part that the EFM signal of 0.6 μ m is recorded in the guide groove of second Information Level 44.When adopting the 18mW recording power, can observe good visual pattern.The shake result who records is 11.7% in platform portion, is 12.1% at slot part, and these numerical value are lower than the reference value 13% of rewrite information.Therefore can be sure of and to reappear satisfactorily.
In an experiment, make this recording medium bear damp and hot environment, temperature is 80 ℃, relative humidity is 80%, continues after 100 hours signal to be carried out comparative determination.Consequently, stoped the variation of shape, redisplaying information stably, and when not considering to change, can record good jitter measurements.
Therefore we can say that method of the present invention is a kind of effective ways of making many Information Levels recording medium.

Claims (4)

1. optical data recording medium comprises:
First substrate has the corresponding informance signal and the information track that forms at least on the one side surface;
First information layer is formed on the surface of above-mentioned first substrate, and has predetermined transmissivity and predetermined reflectivity with respect to light beam;
Second substrate has the corresponding informance signal and the information track that forms at least on the one side surface;
Second Information Level is formed on the surface of above-mentioned second substrate, and has the predetermined reflectivity with respect to above-mentioned light beam; And
Separate layer is formed between above-mentioned first information layer and above-mentioned second Information Level, and this separate layer is transparent with respect to above-mentioned light beam, it is characterized in that,
The described information signal playback time of described first information layer and described second Information Level uses the described light beam of same wavelength,
The track space of the described information track of described first substrate equates with the track space of the described information track of described second substrate,
The width of the above-mentioned information track of above-mentioned second substrate is greater than the width of the above-mentioned information track of above-mentioned first substrate.
2. optical data recording medium comprises:
First substrate has the guide groove of following the tracks of usefulness at least on the one side surface;
First information layer is formed on the surface of above-mentioned first substrate, and has predetermined transmissivity and predetermined reflectivity with respect to light beam;
Second substrate has the guide groove of following the tracks of usefulness at least on the one side surface;
Second Information Level is formed on the surface of above-mentioned second substrate, and has the predetermined reflectivity with respect to above-mentioned light beam; And
Separate layer is formed between above-mentioned first information layer and above-mentioned second Information Level, and this separate layer is transparent with respect to above-mentioned light beam,
The width of the above-mentioned guide groove of wherein above-mentioned second substrate is greater than the width of the above-mentioned guide groove of above-mentioned first substrate.
3. according to the optical data recording medium of claim 2, the spacing of the above-mentioned guide groove of wherein above-mentioned second substrate is greater than the spacing of the above-mentioned guide groove of above-mentioned first substrate.
4. optical data recording medium comprises:
First substrate has the corresponding informance signal and the information track that forms at least on the one side surface;
First information layer is formed on the surface of above-mentioned first substrate, and has predetermined transmissivity and predetermined reflectivity with respect to light beam;
Second substrate has the corresponding informance signal and the information track that forms at least on the one side surface;
Second Information Level is formed on the surface of above-mentioned second substrate, and has the predetermined reflectivity with respect to above-mentioned light beam; And
Separate layer is formed between above-mentioned first information layer and above-mentioned second Information Level, and this separate layer is transparent with respect to above-mentioned light beam, it is characterized in that,
The described information signal playback time of described first information layer and described second Information Level uses the described light beam of same wavelength,
The track space of the described information track of described first substrate equates with the track space of the described information track of described second substrate,
When a side of above-mentioned light beam incident is watched, the concave and convex direction of the above-mentioned information track of above-mentioned first substrate and above-mentioned second substrate is opposite mutually.
CNB200610101645XA 1995-04-07 1996-04-08 Optical information recording medium Expired - Lifetime CN100520922C (en)

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CNB2006101005845A Expired - Fee Related CN100466080C (en) 1995-04-07 1996-04-08 Optical information recording medium, manufacturing method therefor, manufacturing apparatus therefor, and optical information recording and reproducing apparatus
CN2006101016356A Expired - Lifetime CN1897123B (en) 1995-04-07 1996-04-08 Optical information recording medium, manufacturing method therefor, manufacturing apparatus therefor, and optical information recording and reproducing apparatus
CNB200610101645XA Expired - Lifetime CN100520922C (en) 1995-04-07 1996-04-08 Optical information recording medium
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CN1877721A (en) 2006-12-13
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CN1937043A (en) 2007-03-28
CN1937044A (en) 2007-03-28

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