Method for writing and reading data on a multi-layer recordable interferometric optical disc and method for fabricating such

• US 5,669,995 A
• Filed: 01/29/1996
• Issued: 09/23/1997
• Est. Priority Date: 01/29/1996
• Status: Expired due to Term

• Current Assignee: Intermag, Inc.
• Original Assignee: Gilbert H. Hong
• Inventors: Hong, Gilbert H.
• Primary Examiner(s): Ball, Michael W.
• Assistant Examiner(s): Tolin, Michael A.
• Application Number:
  US08/593,694
• Time in Patent Office: 603 Days
• Field of Search: 369/94, 369/109, 369/121, 369/122, 369/275.4, 369/286, 369/284, 156/242, 156/247, 156/230, 156/235, 156/237, 156/239, 156/272.8, 156/232, 156/272.2, 156/74, 156/246, 156/249, 428/64.1, 428/64.4, 428/64.8, 428/64.9
• US Class Current: 369/94
• CPC Class Codes: B29D 17/005 Producing optically read record carriers, e.g. optical discs
• CPC Class Codes: G11B 7/00 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 G11B11/00, G11B13/00 take precedence
• CPC Class Codes: G11B 7/0037 with discs
• CPC Class Codes: G11B 7/0045 Recording G11B7/006, G11B7/0065 take precedence
• CPC Class Codes: G11B 7/005 Reproducing G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/127 Lasers; Multiple laser arrays lasers per se H01S
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007
• CPC Class Codes: G11B 7/24038 Multiple laminated recording layers
• CPC Class Codes: G11B 7/244 comprising organic materials only
• CPC Class Codes: G11B 7/26 Apparatus or processes specially adapted for the manufacture of record carriers
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10S 430/146 Laser beam
• CPC Class Codes: Y10T 428/21 Circular sheet or circular blank

Abstract

A recordable compact disc comprises a 0.6 millimeter clear plastic or glass substrate on which is grown a thin-film image layer having several distinct recording planes. Each recording plane is separated from the next by a clear plastic layer. Each recording plane includes an organic dye layer in combination with another clear layer that has a different index of refraction. Different color dyes are used for each recording plane. A method for storing and reading data to and from a multilayer recordable compact disc with different color dye layers uses high powered color lasers to write each recording plane and low powered monochromatic reading lasers that are sensitive to the constructive and destructive light interference effects caused by micron variations in the clear plastic layers in each recording plane. The micron variations used for each recording plane are unique and chosen along with the monochromatic reading laser colors to have minimal crosstalk between recording-plane data channels.

Claims

1. A method for making and recording data in an optical disc, the method comprising the steps of:

depositing a polymer solution or UV curable monomer liquid on a master disc with pre-recording grooves;

spin-coating said master disc with said polymer solution or UV curable monomer liquid to form a first clear film having a first thickness between zero to 10 microns;

curing said first clear film to harden it;

fabricating a clear plastic or glass substrate in the shape of a flat disk approximately between zero and 1.2 millimeters thick;

peeling-off said first clear film from said master and attaching it to said clear plastic or glass substrate with the grooved side exposed;

spin-coating a first color dye layer over said first clear film, wherein the material of said first color dye layer and said first clear film have substantially different indices of refraction;

depositing a first reflective layer over said first color dye layer to complete the first recordable layer; and

applying a protective lacquer coating to complete the single layer disc.

2. The method of claim 1, further comprising the steps of:

repeating the steps of depositing, spin-coating and curing;

peeling off said second clear film from said second master and laminating it to said first recordable layer with the grooved side exposed;

repeating the steps of spin-coating and depositing to complete a second recordable layer; and

applying a protective lacquer coating to complete the double layer disc or adding more recordable layers to have a multiple layered structure, then applying protective lacquer coating to complete the disc.

3. The method of claim 2, further comprising the step of:

obtaining spatial resolution by laminating the layers in a multiple layered storage disc such that separations between layers are larger than the depth of focus of the reading laser, wherein each layer can be addressed individually without cross-talk from others.

4. The method of claim 1, further comprising the step of:

writing a first set of data to said first color dye layer and said first clear film by heating portions of said first color dye layer with a laser "W1" of the same color (wavelength) such that said heated portions of said first color dye layer shrink in thickness and first clear film expands, wherein the transmissivity of light through said heated and not heated portion is substantially different such that the heated portion represents digital one and the unheated portion represents digital zero or vice versa.

5. The method of claim 4, further comprising the steps of:

reading said first set of data by exposing said heated and not heated portion of the said first color dye and said first clear film with first monitoring laser light "R1"; and

interpreting said transmissivity variation as representing digital encoding of said first set of data.

6. The method of claim 5, further comprising the step of:

optimizing laser power "W1" and writing time, the thickness of heated and not heated portion of the clear film is made to be in resonance with "R1", leading to constructive and destructive interferometric that is specific to "R1", wherein spectral resolution is achieved.

7. The method of claim 1, wherein:

using plastic materials that are polycarbonate, PMMA, nitrocellulose and other optical plastics and glass materials that are low expansion glass, chemically tempered glass or other optical glass;

using dyes that are photosensitive and decomposed by light such as cyanine dyes and phthalocyanines dyes and the partially reflective layers that are metal layers such as silver, gold or aluminum; and

using photo-sensitive material such as amorphous silicon that changes colors through reversible phase transitions, for reversible and erasable memory.

8. The method of claim 1, further comprising the steps of:

doping the polymer solution or monomer liquid with a fluorescent dye or an absorber;

fabricating clear thin film with pre-recording grooves using the said solution or said monomer liquid; and

monitoring wavelengths of the reading signal by the emission peak of the fluorescent dye or absorption peak of the absorber.

9. A method for making and recording data in an optical disc, the method comprising the steps of:

fabricating a clear plastic disc in the shape of a flat disk approximately between zero and 1.2 millimeters thick by injection molding with pre-recording grooves;

depositing the first organic dyes on the grooved side and depositing a partially reflective layer to complete the first recording layer;

depositing a polymer solution or UV curable monomer liquid on a master disc with pre-recording grooves;

spinning said master disc with said polymer solution or UV curable monomer liquid to form a clear film having a first thickness between zero to ten microns;

curing said clear film to harden it;

peeling off said clear film from said master and attaching it to said plastic disc with the first recordable layer with the grooved side exposed;

spin-coating a second color dye layer over said clear film, wherein the material of said color dye layer and said clear film have substantially different indices of refraction;

depositing a partially reflective layer over said color dye layer to complete the second recordable layer; and

applying a protective lacquer coating to complete the disc.

10. The method of claim 9, further comprising the steps of:

repeating the steps of depositing, spinning and curing;

peeling off said clear film from said master and laminating it to said double layered disc with the grooved side exposed;

spin-coating a third color dye layer over said clear film, wherein the material of said third color dye layer and said clear film have substantially different indices of refraction;

depositing the third partially reflective layer over said third color dye layer to complete the third recordable layer; and

applying a protective lacquer coating to complete the disc or adding more recordable layers to have a multiple layered structure, then, applying a protective lacquer coating to complete the disc.

11. The method of claim 9, further comprising the step of:

laminating the layers in a multiple layered storage disc such that separations between layers are larger than the depth of focus of the reading laser.

12. The method of claim 10, further comprising the step of:

laminating the layers in a multiple layered storage disc such that separations between layers are larger than the depth of focus of the reading laser.

13. The method of claim 9, further comprising the steps of:

using plastic materials that are polycarbonate, PMMA, nitrocellulose and other optical plastics and glass materials that are low expansion glass, chemically tempered glass or other optical glass;

using dyes that are photosensitive and decomposed by light such as cyanine dyes and phthalocyanines dyes and the partially reflective layers that are metal layers such as silver, gold or aluminum; and

using dyes that can be other material such as amorphous silicon that changes colors through reversible phase transitions, for reversible and erasable memory.

14. The method of claim 10, further comprising the steps of:

using plastic materials that are polycarbonate, PMMA, nitrocellulose and other optical plastics and glass materials that are low expansion glass, chemically tempered glass or other optical glass;

using dyes that are photosensitive and decomposed by light such as cyanine dyes and phthalocyanines dyes and the partially reflective layers that are metal layers such as silver, gold or aluminum; and

using dyes that can be other material such as amorphous silicon that changes colors through reversible phase transitions, for reversible and erasable memory.

15. The method of claim 9, further comprising the steps of:

writing a first set of data to said first color dye layer and said first clear film by heating portions of said first color dye layer with a laser "W1" of the same color (wavelength) such that said heated portions of said first color dye layer shrinks in thickness and first clear film expands, wherein the transmissivity of light through said heated and not heated portion is substantially different such that the heated portion represents digital one and the unheated portion represents digital zero or vice versa; and

writing a second set of data to said second color dye layer and said second clear film by heating portions of said second color dye layer with a laser "W2" of the same color (wavelength) such that said heated portions of said second color dye layer shrinks in thickness and second clear film expands, wherein the transmissivity of light through said heated and not heated portion is substantially different such that the heated portion represents digital one and the unheated portion represents digital zero or vice versa.

16. The method of claim 10, further comprising the steps of:

writing a first set of data to said first color dye layer and said first clear film by heating portions of said first color dye layer with a laser "W1" of the same color (wavelength) such that said heated portions of said first color dye layer shrinks in thickness and first clear film expands, wherein the transmissivity of light through said heated and not heated portion is substantially different such that the heated portion represents digital one and the unheated portion represents digital zero or vice versa;

writing a second set of data to said second color dye layer and said second clear film by heating portions of said second color dye layer with a laser "W2" of the same color (wavelength) such that said heated portions of said second color dye layer shrinks in thickness and second clear film expands, wherein the transmissivity of light through said heated and not heated portion is substantially different such that the heated portion represents digital one and the unheated portion represents digital zero or vice versa; and

writing a third set of data to said third color dye laser and said third clean film by heating portions of said third color dye layer with a laser "W3" of the same color (wavelength); and

additional writing of additional data in additional layers is done until all data is recorded in a multiple-layered disc.

17. The method of claim 15, further comprising the steps of:

reading said first set of data by exposing said heated and not heated portions of said first color dye and plastic layer and said first clear film with said first monochromatic laser light "R1" and interpreting said light intensity radiation as representing digital encoding of said first set of data; and

reading said second set of data by exposing said heated and not heated portions of said second color dye and plastic layer and said second clear film with said second monochromatic laser light "R2" and interpreting said light intensity radiation as representing digital encoding of said second set of data.

18. The method of claim 16, further comprising the steps of:

reading said first set of data by exposing said heated and not heated portions of said first color dye and plastic layer and said first clear film with said first monochromatic laser light "R1" and interpreting said light intensity radiation as representing digital encoding of said first set of data;

reading said second set of data by exposing said heated and not heated portions of said second color dye and plastic layer and said second clear film with said second monochromatic laser light "R2" and interpreting said light intensity radiation as representing digital encoding of said second set of data;

reading said third set of data by exposing said heated and not heated portions of said third color dye and plastic layer and said third clear film with said third laser light "W3" and interpreting said light intensity radiation as representing digital encoding of said third set of data; and

additional reading of additional data with additional laser "Wn" is done in a similar fashion until all data is retrieved from a multiple-layered disc.

19. The method of claim 9, wherein:

the steps of making the clear film includes the use of a fluorescent dye or an absorber as dopant embedded in the clear film.

20. The method of claim 10, wherein:

the steps of making the clear film includes the use of a fluorescent dye or an absorber as dopant embedded in the clear film.

21. The method of claims 9, wherein:

the steps of depositing color dye and plastic layers are such that the choice of color of said color dye depends on the depth order of each of said color dye and plastic layers.

22. The method of claim 10, wherein:

the steps of depositing color dye and plastic layers are such that the choice of color of said color dye depends on the depth order of each of said color dye and plastic layers.

23. The method of claim 9, wherein:

the steps of depositing color dye and plastic layers are such that the choice of color of said color dye depends on the depth order of each of said color dye and plastic layers;

the steps of reading and writing are such that said reading and writing lasers, W1, R1, W2, and R2, are such that said first dye layer is transmissive to the W2 and R2 wavelengths, and opaque to the W1 wavelength; and

the steps of reading and writing are such that said reading and writing lasers, W1, R1, W2, and R2, are such that said second dye layer is opaque to the W2 wavelength.

24. The method of claim 10, wherein:

the steps of depositing color dye and plastic layers are such that the choice of color of said color dye depends on the depth order of each of said color dye and plastic layers;

the steps of reading and writing are such that said reading and writing lasers, W1, R1, W2, and R2, are such that said first dye layer is transmissive to the W2 and R2 wavelengths, and opaque to the W1 wavelength; and

the steps of reading and writing are such that said reading and writing lasers, W1, R1, W2, and R2, are such that said second dye layer is opaque to the W2 wavelength.