Incorporation of markings in optical media

• US 7,393,623 B2
• Filed: 11/05/2003
• Issued: 07/01/2008
• Est. Priority Date: 06/06/2001
• Status: Expired due to Fees

• Current Assignee: Spectra Systems Corporation
• Original Assignee: Spectra Systems Corporation
• Inventors: Smuk, Andrei, Pizzuti, Thomas, Conroy, Jeffrey L, Lewis, Dana, Lawandy, Nabil M, Berube, Allison, Afzal, Robert S
• Primary Examiner(s): Walke; Amanda
• Application Number:
  US10/702,530
• Publication Number:
  US 20040121268A1
• Time in Patent Office: 1,700 Days
• Field of Search: 430/270.1, 430/302, 430/280.1, 430/321, 235/435
• US Class Current: 430/270.1
• CPC Class Codes: G11B 7/24094 Indication parts or information parts for identification
• CPC Class Codes: G11B 7/252 of layers other than recording layers

Abstract

Optical media having markings that are non-interfering, or substantially non-interfering with readout of data from the optical media are disclosed. The optical media make use of certain formulations of color forming coatings described herein. Protective coatings used to enhance the color forming coatings are also presented. Methods for incorporating the coatings into the optical media are included. In preferred embodiments, the marking is formed in a photosensitive coating that is applied to the optical media, and then cured with a first light. A second light, having a substantially separate band of wavelengths from the first light, is used to image a marking into the coating. The coating is robust to many external influences, such as ambient environmental conditions, and physical wear.

Claims

1. A method for producing an optical disc, comprising:

selecting a formulation comprising a photocurable base material cured by exposure to ultraviolet (UV) light corresponding to a first set of wavelengths, at least one set of photoacid generators (PAGS) responsive to ultraviolet (UV) marking light corresponding to a second set of wavelengths substantially distinct from the first set of wavelengths, and a material that changes that changes its light absorption characteristics in response to a change of pH to form at least one marking is adapted for forming at least one marking upon exposure to a source of marking light, wherein the marking light is ultraviolet light corresponding to the second set of wavelengths, wherein the first layer is comprised of hexanediol diacrylate;

triphenylsulfonium triflate and a color former;

applying the formulation in at least a portion of a first layer of the optical media;

curing the first layer;

forming the at least one marking by exposure to marking light having wavelengths in the second set of wavelengths;

wherein the marking, when formed, appears in at least a readout area of the optical media and is substantially non-interfering with a readout light for the optical media, wherein said formulation is sensitive to only ultraviolet (UV) light, wherein the optical media is capable of storing data;

applying a second layer onto the first layer, wherein the second layer is comprised of a crosslinkable silicone polyether acrylate;

tris (2-hydroxy ethyl) isocyanurate triacrylate; and

a difunctional bisphenol A based epoxy acrylate; and

curing the second layer.

2. The method as in claim 1, wherein the marking is substantially non-interfering with wavelengths of about 400 nm, about 440 nm, about 630 nm, about 650 nm and about 780 nm.

3. The method as in claim 1, wherein applying comprises spincoating the formulation.

4. The method as in claim 1, wherein applying the formulation comprises injection molding.

5. The method as in claim 1, further comprising forming an image by exposing the at least a portion of the first layer to patterned marking light.

6. The method as in claim 5, wherein exposing comprises one of using a photomask and a direct writing laser.

7. The method as in claim 1, the second set of wavelengths comprising wavelengths below about 320 nm, the second set of wavelengths being substantially distinct from the first set of wavelengths.

10. The optical media as in claim 1, wherein the first layer comprises at least one of:

a stable liquid mixture of trimethylbenzoyldiphenylphosphine oxide, α

-hydroxyketones, and benzophenone derivatives;

Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide;

an eutectic liquid mixture of;

2,4,6 trimethylbenzophenone and 4 methylbenzophenone; and

a mixture of about 50% 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide and about 50% 2-Hydroxy-2-methyl-1-phenyl-propan-1-one.

11. The optical media as in claim 1, wherein the optical data storage media is a compact disc (CD).

12. The optical media as in claim 1, wherein the optical data storage media is a digital versatile disc (DVD).

13. The optical media as in claim 1, the first layer further comprising tris (2-hydroxy ethyl) isocyanurate triacrylate.

14. The optical media as in claim 13, wherein the readout light and marking light correspond to non-overlapping bands of ultraviolet light.

8. An optical media, comprising:

a first layer comprising hexanediol diacrylate;

triphenylsulfonium triflate and a color former, the first layer being cured by ultraviolet light ultraviolet light corresponding to a first set of wavelengths, the first layer capable of forming a marking upon exposure to ultraviolet light corresponding to a second set of wavelengths, wherein the second set of wavelengths is substantially distinct from the first set of wavelengths; and

a second layer comprising a crosslinkable silicone polyether acrylate;

tris (2-hydroxy ethyl) isocyanurate triacrylate; and

a difunctional bisphenol A based epoxy acrylate, the second layer being cured by ultraviolet light, wherein the marking, when formed, is apparent within a readout area of the optical media, the optical media is an optical data storage media, and the marking is substantially non-interfering with a readout light for reading stored data from a data readout area of the optical media.

9. An optical media as in claim 8,

wherein the optical media is an optical data storage media, the marking being created by one of a uniform exposure and a patterned exposure by the second set of wavelengths.

15. The optical media as in claim 8, wherein the first set of wavelengths comprises wavelengths above about 370 nm.

16. The optical media as in claim 8, wherein the second set of wavelengths comprises wavelengths in the range of between about 270 nm and about 320 nm.

17. The optical media as in claim 8, wherein the first layer comprises at least one of:

1,6 hexanediol diacrylate;

tetrahydrofuifuryl acrylate;

tris (2-hydroxy ethyl) isocyanurate triacrylate;

a difunctional bisphenol A based epoxy acrylate;

tris (2-hydroxy ethyl) isocyanurate triacrylate;

2-phenoxyethyl acrylate;

a difunctional bisphenol A based epoxy acrylate blended with about 40% 1,6 hexanediol diacrylate; and

a difunctional bisphenol A based epoxy acrylate blended with about 50%, 2-phenoxyethyl acrylate.

18. The optical media as in claim 8, wherein the first layer comprises a wetting agent.

19. The optical media as in claim 18, wherein the wetting agent comprises at least one of a polyether modified poly-dimethyl-siloxane;

a crosslinkable silicone polyether acrylate; and

a crosslinkable silicone acrylate.

20. The optical media as in claim 18, wherein a formulation of the coating comprises the wetting agent in a range of between about 0.3 weight percent and about 1 weight percent.

21. The optical media as in claim 8, wherein the triphenylsulfonium triflate is in a range of between about 1.5 weight percent to about 9 weight percent of the first layer.

22. The optical media as in claim 8, wherein the first layer comprises polyether modified poly-dimethyl-siloxane;

a stable liquid mixture of trimethylbenzoyldiphenylphosphine oxide, α

-hydroxyketones, and benzophenone derivatives;

1,6 hexanediol diacrylate;

tetrahydrofurfuryl acrylate;

ethoxylated (4) pentaerythritol tetraacrylate; and

a highly propoxylated (5.5) glyceryl triacrylate.

23. The optical media as in claim 8, wherein said first layer comprises at least one of the following UV photoabsorptive materials:

2-(2H-benzotriazol-2-yl )-6-dodecyl -4-methylphenol and 2,2′

-dihydroxy-4-methoxybenzophenone.

24. The optical media as in claim 8, wherein the marking is exhibited in the collective appearance of a plurality of layers.

25. The optical media as in claim 24, wherein at least two of the plurality of layers have different colors.

26. The optical media as in claim 8, wherein the marking degrades over time.

27. The optical media as in claim 24, wherein at least two of the plurality of layers are adapted to have different markings.

28. The optical media as in claim 8, wherein the marking comprises at least one of an image, an alphanumeric character, a symbol, a graphic, a datacode symbology and a digital watermark.

29. The optical media as in claim 8, wherein the first layer comprises a substrate layer.

30. The optical media as in claim 8, wherein the first layer comprises a bonding layer.

31. The optical media as in claim 8, wherein the first layer comprises a protective layer.

32. The optical media as in claim 8, wherein the marking comprises a grayscale marking.

33. The optical media as in claim 8, wherein the marking comprises a single color marking.

34. The optical media as in claim 8, wherein the marking comprises a multi-color marking.

35. The optical media as in claim 8, further comprising a third layer formed over the second layer, wherein the third layer is capable of forming a marking that is apparent in at least the readout area of the optical media and is substantially non-interfering with a readout light for the optical media, the third layer comprising a formulation sensitive only to ultraviolet (UV) light.

36. The optical media as in claim 35, wherein a frequency of the ultraviolet light said formulation of said third layer is sensitive to is different from a frequency of the ultraviolet light said formulation of said first layer is sensitive to.

37. The optical media as in claim 35, wherein a frequency of the ultraviolet light said formulation of said third layer is sensitive to is equal to a frequency of the ultraviolet light said formulation of said first layer is sensitive to.

38. The optical media as in claim 8, wherein the first layer is a substrate layer, the optical media comprising in the following order:

a protective layer;

a metallized layer; and

the substrate layer.

39. The optical media as in claim 8, wherein the first layer further comprises tetrahydrofurfuryl acrylate.

40. The optical media as in claim 8, wherein the second layer further comprises 2,2′

-dihydroxy-4-methoxybenzophenone.

41. An optical media as in claim 8, wherein the optical media is a compact disc (CD).

42. An optical media as in claim 8, wherein the optical media is a digital versatile disc (DVD).

43. The optical media as in claim 8, wherein the first layer has the marking formed in it after exposure to ultraviolet light.

44. An optical media as in claim 8, wherein a wavelength of the readout light is one of the group consisting of 408 nm, 440 nm, 630 nm, 650 nm, and 780 nm.

45. The optical media as in claim 8, wherein the curing light for the first and second layers has a wavelength above about 370 nm.

46. The optical media as in claim 45, wherein the marking light for the first layer has a wavelength below 320 nm.

47. The optical media as in claim 8, wherein the change in light absorption characteristics results in the marking.

48. The optical media as in claim 47, wherein the marking is machine-readable.