Method and apparatus for storing and retrieving information using optical data storage media

1. A method of manufacturing cholesteric liquid crystal (CLC) optical storage media comprising:

fabricating a master mold for the cholesteric liquid crystal optical storage media;

using the master mold to press a plurality of stamping molds of opposite image and plating the stamping molds to increase surface hardness, wherein the stamping mold has protrusions where a first logical binary bit is recorded, and pits where a second opposite logical binary bit is recorded;

installing the stamping mold in a stamping machine and heating the stamping mold;

injecting a quantity of plastic into the stamping mold and pressing the quantity of plastic;

ejecting a pressed disk having pits of one micron or deeper where the first logical binary bits are recorded;

filling the pits with CLC material having a negative dielectric anisotropy.

2. The method as in claim 1 , wherein fabricating the master mold comprises:

applying a photoresist layer onto a flat substrate;

directly exposing the photoresist layer along a continuous spiral track with a focused laser beam;

developing the exposed photoresist using a wet chemical etching agent or a dry plasma etching agent, wherein areas of the substrate coated with photoresist correspond to logical bit values;

evaporating a thin metal film onto the etched away surface of the substrate; and

washing away unexposed photoresist having metal film on top, leaving a metal thin film dot pattern corresponding to a digital data pattern encoded into the substrate.

3. The method as in claim 2 , wherein applying the photoresist is accomplished by spin coating.

4. The method as in claim 2 , wherein the photoresist is a positive photoresist.

5. The method as in claim 2 , wherein the photoresist is a negative photoresist.

6. The method as in claim 2 , wherein exposure of the photoresist layer is at a constant linear velocity.

7. The method as in claim 2 , wherein exposure of the photoresist layer is at a constant angular velocity.

8. The method as in claim 2 , wherein exposure of the photoresist layer is controlled by digitally modulating the laser beam using an encoded digital signal.

9. The method as in claim 8 , wherein the encoded digital signal is fed sequentially.

10. The method as in claim 8 , wherein the encoded digital signal is fed in reverse order.

11. The method as in claim 2 , further comprising repairing opens, pinholes, shorts or other defects of the metal thin film dot pattern using laser deposition or deletion.

12. The method as in claim 2 , further comprising increasing hardness of the metal thin film dot pattern using vacuum deposition or electrode-less plating.

13. The method as in claim 2 , wherein the substrate is an optically transparent material.

14. The method as in claim 2 , wherein the rectilinear (x,y) coordinates of the focused laser beam are servo-controlled by laser interferometers which have an accuracy within 5 nanometers.

15. The method as in claim 2 , wherein the polar (r, θ) coordinates of the focused laser beam are servo-controlled by laser interferometers which have an accuracy within 5 nanometers, and the θ-position is controlled by an angular encoder mounted on a spinning shaft supporting the substrate, the angular encoder having an accuracy within 10 milli-arcseconds.

16. The method as in claim 1 , wherein fabricating the master mold comprises:

applying a photoresist layer onto a flat substrate;

carrying out a photoablative process using an excimer laser to directly etch a digital data pattern into a surface of the substrate, using a laser beam having ultraviolet spectral components that photochemically decompose the photoresist;

evaporating a thin metal film onto the etched away surface of the substrate; and

washing away unexposed photoresist having metal film on top, leaving a metal thin film dot pattern corresponding to a digital data pattern encoded into the substrate.

17. The method as in claim 1 , wherein the CLC material is selected from the group of polymeric liquid crystals consisting of polysiloxanes, di-acrylates, di-epoxides, and di-vinylethers.

18. The method as in claim 1 , wherein the CLC material comprises nematic liquid crystals with chiral additives.

19. The method as in claim 1 , wherein the CLC material further comprises chiral additives.

20. A method of manufacturing cholesteric liquid crystal (CLC) optical storage media comprising:

fabricating a first master mold for the cholesteric liquid crystal optical storage media;

using the first master mold to press a plurality of first stamping molds of opposite image and optionally plating the first stamping molds to increase surface hardness, wherein the first stamping mold has protrusions where a first logical binary bit is recorded, and pits where a second opposite logical binary bit is recorded;

installing the first stamping mold in a stamping machine and heating the first stamping mold,

injecting a first quantity of plastic into the stamping mold and pressing the first quantity of plastic;

ejecting a first pressed disk having pits of one micron or deeper where the first logical binary bits are recorded;

filling the pits of the first pressed disk with CLC material having a negative dielectric anisotropy creating a first pressed disk data surface;

fabricating a second master mold for the cholesteric liquid crystal optical storage media;

using the second master mold to press a plurality of second stamping molds of opposite image and optionally plating the second stamping molds to increase surface hardness, wherein the second stamping mold has protrusions where a first logical binary bit is recorded, and pits where a second opposite logical binary bit is recorded;

installing the second stamping mold in a stamping machine and heating the second stamping mold,

injecting a second quantity of plastic into the stamping mold and pressing the second quantity of plastic;

ejecting a second pressed disk having pits of one micron or deeper where the first logical binary bits are recorded;

filling the pits of the second pressed disk with CLC material having a negative dielectric anisotropy creating a second pressed disk data surface; and

laminating the surface of the first pressed disk opposite the first pressed disk data surface to surface of the second pressed disk opposite the second pressed disk data surface.

21. The method as in claim 20 , further comprising capping the first and second pressed disk data surfaces with a transparent plastic film.

22. A method of manufacturing cholesteric liquid crystal (CLC) optical storage media comprising:

fabricating a first mold portion having protrusions where a first logical binary bit is recorded, and pits where a second opposite logical binary bit is recorded;

fabricating a second mold portion having protrusions where a first logical binary bit is recorded, and pits where a second opposite logical binary bit is recorded;

installing the first and second mold portions opposite one another in a stamping machine;

injecting a quantity of plastic into the stamping mold and pressing the quantity of plastic;

ejecting a pressed disk having opposing data surfaces each including pits of one micron or deeper where the first logical binary bits for each surface are recorded;

filling the pits with CLC material having a negative dielectric anisotropy;

capping the opposing data surfaces of the pressed disk with plastic; and

aligning CLC molecules of the CLC material using either an external magnetic field or an external electric field.