HIGH CAPACITY DIGITAL DATA STORAGE
BY TRANSMISSION OF RADIANT ENERGY
THROUGH ARRAYS OF SMALL DIAMETER
CROSS REFERENCE TO RELATED
This application is a continuation application of U.S. patent application Ser. No. 10/082,928 filed Oct. 19, 2001, 10 which claims benefit to U.S. Provisional Application No. 60/242,042 filed on Oct. 20, 2000 which are hereby incorporated by reference in their entirety.
This application is also related to U.S. patent application Ser. No. 11/370,756, filed Mar. 08, 2006. 15
The present invention relates generally to digital data storage, and more particularly, to high capacity digital data stor- 20 age.
Compact Discs (CD's) and Digital Versatile Disks 25 (DVD's) have been developed to increase the amount of data that can be stored on a storage medium. These types of storage media have data on them in the form of pits and lands that are written and read with lasers along a track. Generally, the track is helical in shape and each pass of the track is separated from adj acent passes of the track by a track pitch. A standard single sided CD can store approximately 800 Megabytes of data, while a double-sided CD can store 1600 Megabytes of data. A DVD, has a track pitch of about 0.74 microns and a single side/single layer DVD can store about 4.4 Gigabytes of data, 35 which is roughly equivalent to about 2 hours of movie playing time.
Therefore, some movies and other types of digital content cannot fit on a CD and can very easily be too large to even fit on a DVD. Furthermore, with the advent of certain technologies and business plans for the distribution of "content", it may be advantageous to store a library of digital content, such as movies, on a single removable storage medium. Current CD's and DVD's cannot be used for such purposes. ^
Therefore it is an object of the present invention to provide a data storage medium having a higher storage density than the storage mediums of the prior art.
Accordingly, a storage media for storage of data thereon is provided. The storage media comprises: a first layer, the first layer being substantially transparent to a predetermined radiant energy used for reading the data; and a second layer 55 formed on the first layer and being substantially opaque to the radiant energy, the second layer having a pattern comprising a plurality of holes, each of the holes (or at least one of the holes) having a largest dimension which is greater than a wavelength of the radiant energy, the data being stored as the 60 presence or absence of a hole in the pattern.
Preferably, the first layer is polycarbonate and the second layer is a metalization coating. The metalization coating is preferably aluminum.
Preferably, the plurality of holes are circular and the largest 65 dimension is a diameter of the circular holes. The diameter of the holes is preferably in the range of about 30 to 100 nanom
eters with a distance between successive holes preferably being in a range of about 30 to 100 nanometers.
The pattern preferably comprises the plurality of holes arranged along a helix beginning near a center of the storage media and extending spirally outward, each successive pass of the helix being separated from a previous pass of the helix by a track pitch. The track pitch is preferably about 100 nanometers.
Preferably, the plurality of holes are circular and the largest dimension is a diameter of the circular holes, the diameter of the holes being about 50 nanometers, a distance between successive holes being about 100 nanometers, and the track pitch being about 100 nanometers. Alternatively, the diameter of the holes being about 30 nanometers, a distance between successive holes is about 60 nanometers, and the track pitch being about 100 nanometers.
Preferably, the storage media further comprises a third layer, the third layer being disposed on the second layer and being substantially transparent to the radiant energy. The third layer is preferably acrylic.
The storage media is preferably circular in shape and has a data storage area having an inner diameter of about 25 millimeters and an outer diameter of about 115 millimeters.
Further provided is an apparatus for reading the storage media. The apparatus comprises: a radiant energy source having an output of radiant energy directed towards the plurality of data holes; and a plurality of detectors for detecting the radiant energy diffusing from the plurality of data holes.
The radiant energy source is preferably a blue laser diode or an ultraviolet laser diode. The radiant light source preferably has a wavelength in the range of about 50 nanometers to 450 nanometers and most preferably a wavelength of about 410 nanometers.
The detectors are preferably photodetectors. The photodetectors are preferably formed of a wide bandgap material, such as silicon carbide, gallium arsenide, gallium nitride, aluminum nitride, zinc selenide, gallium nitride/aluminum nitride alloy, aluminum nitride/silicon carbide alloy and aluminum gallium nitride/gallium nitride.
The apparatus preferably further comprises a mask positioned between the storage media and the detectors for reducing interference from the radiant energy diffusing through unintended data holes. The mask preferably comprises a material having a pattern of mask holes arranged to restrict the number of data holes observed by a single detector. Preferably, the mask holes are rectangular in shape and have a smaller side dimension approximately equal to the largest dimension of the data holes.
Preferably, the radiant energy source is positioned on the side of the storage media having the first layer and is directed towards the detectors that are positioned on the side of the storage media opposite the first layer.
Still yet provided is a method for reading the storage media. The method comprises: directing radiant energy from a radiant energy source towards the plurality of data holes; and detecting the radiant energy diffusing from the data holes with a plurality of detectors.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where: