EP1419503A1 - Multilayer optical disc - Google Patents

Multilayer optical disc

Info

Publication number
EP1419503A1
EP1419503A1 EP02756425A EP02756425A EP1419503A1 EP 1419503 A1 EP1419503 A1 EP 1419503A1 EP 02756425 A EP02756425 A EP 02756425A EP 02756425 A EP02756425 A EP 02756425A EP 1419503 A1 EP1419503 A1 EP 1419503A1
Authority
EP
European Patent Office
Prior art keywords
disc
reflective material
layers
layer
pit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02756425A
Other languages
German (de)
French (fr)
Other versions
EP1419503A4 (en
Inventor
Iosif Diskine
Mihail Kvasha
Eugene Levich
Alexey Lezhnev
Jacob Malkin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
D Data Inc
Original Assignee
TriD Store IP LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TriD Store IP LLC filed Critical TriD Store IP LLC
Publication of EP1419503A1 publication Critical patent/EP1419503A1/en
Publication of EP1419503A4 publication Critical patent/EP1419503A4/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2403—Layers; Shape, structure or physical properties thereof
    • G11B7/24035—Recording layers
    • G11B7/24038—Multiple laminated recording layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2403—Layers; Shape, structure or physical properties thereof
    • G11B7/24062—Reflective layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/26—Apparatus or processes specially adapted for the manufacture of record carriers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/007—Arrangement of the information on the record carrier, e.g. form of tracks, actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track

Definitions

  • multilayer optical discs There are known multilayer optical discs that were proposed in the following patents: US Patent 6,039,898, Mar. 21 , 2000, B. Glushko and US Patent (reference is made to the IBM multilayer disc Patent).
  • a factor limiting the number of layers in a multilayer disc is loss of the data signal that is picked up by the lens or is incident on the layer that is being read as the beam passes through the multilayer disc.
  • the IBM Company Patent proposes the use of partially reflective layers with phased modulation of the data signal received from pits.
  • the reflective material is positioned only either in the track-forming data elements, i.e. pits (ROM), or the grooves (WORM), while light penetrates the inter-track space without any losses. In this case the losses in each layer are reduced by about 70% in the CD-format and by 50% in the DVD-format. This method also allows to increase the number of layers in the multiple layer disc.
  • Method 1 A data relief pattern is formed on the disc surface by, for example a state-of-the-art CD method. Next, the surface is coated with a reflective material with a reflection coefficient of R. As this material, a metal (ROM) or an alloy of metals or their oxides (WORM) is used whose transmission coefficients can change when they are heated, for example, ITO. Next, using selective etching methods that allow metal removal from the flat surface while leaving it in the recesses, the reflective material is left only in pits or tracks. A selective etching technique that can be used is ion etching of the surface at angle.
  • Method 2 First, a mask is made containing data in the form of pits or grooves (actually, they are hollows made in the metal). Next, a matching system of reflective pits or grooves is formed on the layer surface using the lift-off photolithography technique. To this end, the reflective materials referenced in the previous example are used
  • Method 3 The layer surface is coated with an alloy of metals or their oxides whose transmission coefficients can change when they are heated, for example, ITO.
  • the layer is formatted with a stationary laser unit, by lightening the reflective layer between tracks and pits.
  • the multilayer disc can be fabricated by the methods previously proposed by the authors.

Abstract

To reduce loss of the reading light, a multilayer optical disc (figure 1, disk), such as a disc in a CD or DVD format, has multiple layers (figure 1, layer) with pits or tracks and a reflective material only in the pits or tracks. The disc can be used as a ROM or WORM disc. A methods of making it are also disclosed.

Description

MULTILAYER OPTICAL DISC
BACKGROUND OF THE INVENTION
Field of the Invention
There are known multilayer optical discs that were proposed in the following patents: US Patent 6,039,898, Mar. 21 , 2000, B. Glushko and US Patent (reference is made to the IBM multilayer disc Patent). A factor limiting the number of layers in a multilayer disc is loss of the data signal that is picked up by the lens or is incident on the layer that is being read as the beam passes through the multilayer disc. In this case, in addition to the loss that can be minimized, for example, the process losses that are related to light reflection from the multilayer disc layers and are caused by their different refractive indexes, there are also other losses that are related to the data reading method. For instance, the IBM Company Patent proposes the use of partially reflective layers with phased modulation of the data signal received from pits. The IN signal incident on Layer N would then equal IN = (1 - R)N , where R is the reflection coefficient on a single layer. To reduce losses that occur as the beam passes within a multilayer disc, we propose the following record layout on each layer: the reflective material is positioned only either in the track-forming data elements, i.e. pits (ROM), or the grooves (WORM), while light penetrates the inter-track space without any losses. In this case the losses in each layer are reduced by about 70% in the CD-format and by 50% in the DVD-format. This method also allows to increase the number of layers in the multiple layer disc.
Several methods can be used to form the required system of reflective pits or groves on the layer surface:
Method 1. A data relief pattern is formed on the disc surface by, for example a state-of-the-art CD method. Next, the surface is coated with a reflective material with a reflection coefficient of R. As this material, a metal (ROM) or an alloy of metals or their oxides (WORM) is used whose transmission coefficients can change when they are heated, for example, ITO. Next, using selective etching methods that allow metal removal from the flat surface while leaving it in the recesses, the reflective material is left only in pits or tracks. A selective etching technique that can be used is ion etching of the surface at angle.
Method 2. First, a mask is made containing data in the form of pits or grooves (actually, they are hollows made in the metal). Next, a matching system of reflective pits or grooves is formed on the layer surface using the lift-off photolithography technique. To this end, the reflective materials referenced in the previous example are used
Method 3. The layer surface is coated with an alloy of metals or their oxides whose transmission coefficients can change when they are heated, for example, ITO. Next, the layer is formatted with a stationary laser unit, by lightening the reflective layer between tracks and pits.
The multilayer disc can be fabricated by the methods previously proposed by the authors.

Claims

WHAT IS CLAIMED IS:
1. A multilayer optical disc for storing information, the disc comprising: a plurality of transparent layers; in each of the plurality of layers, a pit or groove pattern for storing the information; and a reflective material disposed only in the pit or groove pattern.
2. The disc of claim 1 , wherein the disc is a ROM disc.
3. The disc of claim 1 , wherein the disc is a WORM disc.
4. A method of making the disc of claim 1 , comprising, for each of the plurality of layers, depositing the reflective material on the layer and etching the reflective material so that the reflective material remains only in the pit or groove pattern.
5. A method of making the disc of claim 1 , wherein the reflective material is applied using a lift-off photolithography technique.
6. A method of making the disc of claim 1 , comprising, for each of the layers, applying a material whose transmission coefficient changes when the material is heated and heating the material with a laser to define the pit or groove pattern.
EP02756425A 2001-07-12 2002-07-12 Multilayer optical disc Withdrawn EP1419503A4 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US30441601P 2001-07-12 2001-07-12
US304416P 2001-07-12
PCT/US2002/021825 WO2003007297A1 (en) 2001-07-12 2002-07-12 Multilayer optical disc

Publications (2)

Publication Number Publication Date
EP1419503A1 true EP1419503A1 (en) 2004-05-19
EP1419503A4 EP1419503A4 (en) 2008-03-26

Family

ID=23176422

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02756425A Withdrawn EP1419503A4 (en) 2001-07-12 2002-07-12 Multilayer optical disc

Country Status (5)

Country Link
EP (1) EP1419503A4 (en)
JP (1) JP2004535646A (en)
KR (1) KR20040054660A (en)
CN (1) CN1602524A (en)
WO (1) WO2003007297A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9275671B2 (en) 2011-06-09 2016-03-01 Case Western Reserve University Optical information storage medium

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4219704A (en) * 1974-10-21 1980-08-26 Eli S. Jacobs Record playback apparatus for optical data records
JPH01171135A (en) * 1987-12-25 1989-07-06 Sharp Corp Optical memory element
JPH05234145A (en) * 1992-02-18 1993-09-10 Brother Ind Ltd Optical recording medium and substrate for optical recording medium
US5455818A (en) * 1992-01-22 1995-10-03 Brother Kogyo Kabushiki Kaisha Optical recording medium
EP0936606A2 (en) * 1998-02-13 1999-08-18 International Business Machines Corporation A laser-writable information recording blank
US6039898A (en) * 1997-05-08 2000-03-21 O.M.D. Optical Memory Devices, Ltd. Optical memory device and a method for manufacturing thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH09326136A (en) * 1996-06-05 1997-12-16 Sony Corp Optical recording medium and its production

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4219704A (en) * 1974-10-21 1980-08-26 Eli S. Jacobs Record playback apparatus for optical data records
JPH01171135A (en) * 1987-12-25 1989-07-06 Sharp Corp Optical memory element
US5455818A (en) * 1992-01-22 1995-10-03 Brother Kogyo Kabushiki Kaisha Optical recording medium
JPH05234145A (en) * 1992-02-18 1993-09-10 Brother Ind Ltd Optical recording medium and substrate for optical recording medium
US6039898A (en) * 1997-05-08 2000-03-21 O.M.D. Optical Memory Devices, Ltd. Optical memory device and a method for manufacturing thereof
EP0936606A2 (en) * 1998-02-13 1999-08-18 International Business Machines Corporation A laser-writable information recording blank

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO03007297A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9275671B2 (en) 2011-06-09 2016-03-01 Case Western Reserve University Optical information storage medium

Also Published As

Publication number Publication date
EP1419503A4 (en) 2008-03-26
WO2003007297A1 (en) 2003-01-23
JP2004535646A (en) 2004-11-25
CN1602524A (en) 2005-03-30
KR20040054660A (en) 2004-06-25

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