Thermal deformation record device with bleachable dye

• US 4,270,130 A
• Filed: 01/08/1979
• Issued: 05/26/1981
• Est. Priority Date: 01/08/1979
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Wrobel, Joseph J., Howe, Dennis G., Thomas, Harold T., Houle, Conrad G., Fike, deceased, Bruce G.
• Primary Examiner(s): MILLER JR, GEORGE
• Application Number:
  US06/001,519
• Time in Patent Office: 869 Days
• Field of Search: 346/1, 346/77 E, 346/135, 96/46 HD, 96/84 R, 358/129, 365/126, 430/50
• US Class Current: 346/77.00E
• CPC Class Codes: G03C 7/02 Direct bleach-out processes; Materials therefor; Preparing or processing such materials
• CPC Class Codes: G11B 7/00452 involving bubble or bump forming
• CPC Class Codes: G11B 7/00455 involving reflectivity, absorption or colour changes
• CPC Class Codes: G11B 7/0052 involving reflectivity, absorption or colour changes
• CPC Class Codes: G11B 7/244 comprising organic materials only
• CPC Class Codes: G11B 7/246 containing dyes
• CPC Class Codes: Y10S 430/146 Laser beam

Abstract

In accordance with the present invention, the optical characteristics of a thermal deformation record device are so altered that the device can be read back using the same beam as was used for recording. Moreover, the read beam can be used for playback at an arbitrarily high power level to enhance the signal-to-noise ratio of the recovered signal and yet not damage the deformation recording.

Claims

1. In a record device comprising a support having superposed thereon a layer of thermal recording material that contains information recorded in the form of a deformation pattern, said thermal recording material in a first state being absorbant to radiation of a selected wavelength for recording of said deformation pattern by exposure to radiation, the improvement wherein said thermal recording material has been converted to a second state wherein it is significantly less absorbant to said exposing radiation.

2. In a record device comprising a support having superposed thereon a layer of thermal recording material comprised of a dye and a binder, said dye in an unaltered form being absorbant to radiation of a selected wavelength for recording of said deformation pattern by exposure to radiation, and said thermal recording material having information recorded therein in the form of a deformation pattern, the improvement wherein said dye is in a state in which it is significantly less absorbant to said exposure radiation, thereby enabling said record device to be read at an increased power level using radiation from the same source as said exposing radiation.

3. In a record device comprised of a support having superposed thereon a layer of thermal recording material, the thermal recording material having information recorded therein in the form of a deformation pattern by exposure to radiation, the improvement wherein:

the spectral characteristics of the thermal recording material have been altered so that the thermal recording material is relatively transparent to radiation at the wavelength or wavelengths of said exposing radiation.

4. In a record device comprised of a support having superposed thereon a layer of thermal recording material that includes a dye, and wherein a deformation pattern has been recorded in the thermal recording material by exposure to radiation, the improvement wherein the dye has been bleached to render it relatively transparent to the wavelength or wavelengths of said exposing radiation without adversely affecting said deformation pattern.

5. A record device as claimed in claim 4 wherein said dye is selected from the group consisting of Iosol Red, SK1 and SK2.

6. In a record device comprised of a support having superposed thereon a layer of thermal recording material that includes a thermally bleachable dye, and wherein a deformation pattern has been recorded in the thermal recording material by exposure to radiation, the improvement wherein the dye has been thermally bleached to render it relatively transparent to the wavelength or wavelengths of said exposing radiation without adversely affecting said deformation pattern.

7. A record device as claimed in claim 6 wherein said dye is Iosol Red.

8. In a record device comprised of a support having superposed thereon a layer of thermal recording material that includes a photobleachable dye, and wherein a deformation pattern has been recorded in the thermal recording material by exposure to radiation, the improvement wherein the dye has been photobleached to render it relatively transparent to the wavelength or wavelengths of said exposing radiation without adversely affecting said deformation pattern.

9. A record device as claimed in claim 8 wherein said dye is selected from the group consisting of Iosol Red, SK1 and SK2.

10. A record device as claimed in claim 8 wherein said thermal recording material is comprised of a mixture of SK1 dye and cellulose nitrate in a ratio between about 1:

1 and about 1;

4 by weight.

11. A record device comprising a layer of thermal recording material that includes a photochromic dye transformable between a first color state absorbant to recording radiation of a given wavelength and a second color state significantly less absorbant to said recording radiation.

12. In a video record device comprised of a layer of thermal recording material having video information recorded in the form of discrete, micron-sized deformations by a recording laser beam, the improvement wherein:

the thermal recording material has been rendered relatively transparent to radiation of the wavelength of the recording laser beam, thereby enabling the recording laser beam to be used for playback at a power level that enhances the signal-to-noise ratio of the recovered information signal.

13. A method of altering the spectral absorption characteristics of a layer of thermal recording material comprised of a dye and a binder, said thermal recording material having information recorded therein in the form of a deformation pattern by exposure to radiation, said method comprising the step of bleaching the dye to render it relatively transparent to said exposing radiation without adversely affecting said deformation pattern.

14. A method as claimed in claim 13 wherein said dye is bleached by a thermal bleaching process.

15. A method as claimed in claim 13 wherein said dye is bleached by a photobleaching process.

16. A method as claimed in claim 13 wherein said dye is bleached by a chemical bleaching process.

17. A method of playing back information recorded in the form of deformations in a layer of thermal recording material, which recording material in a first condition is absorbant to recording laser radiation of a selected wavelength, and which recording material in a second condition is significantly less absorbant to said recording radiation, said method comprising the steps of:

a. altering said thermal recording material from said first condition to said second condition to render it less absorbant to said recording radiation, and

b. illuminating said recorded deformations with radiation from said recording laser to develop a signal indicative of the recorded information without adversely affecting said recorded deformations.

18. A method as claimed in claim 17 further comprising the step of adjusting the power level of said illuminating radiation to maximize the signal-to-noise ratio of the recovered signal.

19. A method of playing back information recorded in the form of a deformation pattern in a layer of thermal recording material, which recording material includes a dye alterable by bleaching from a first state to a second state, in said first state said dye being absorbant to radiation of a selected wavelength for recording said deformations by exposure to a laser beam, and in said second state said dye being significantly less absorbant to said recording radiation, said method comprising the steps of:

a. bleaching said dye to alter it from said first state to said second state, thereby rendering it less absorbant to said recording radiation, and

b. illuminating said recorded deformation pattern with radiation from said recording laser to develop a signal indicative of the recording information without adversely affecting said recorded deformation pattern.

20. A method as claimed in claim 19 further comprising the step of adjusting the power level of said illuminating radiation to maximize the signal-to-noise ratio of the recovered signal.

21. A method as claimed in claim 19 wherein said dye is bleached by a thermal bleaching process.

22. A method as claimed in claim 19 wherein said dye is bleached by a photobleaching process.

23. A method as claimed in claim 19 wherein said dye is bleached by a chemical bleaching process.

24. In a method of preparing a thermal deformation record device comprising the steps of forming a layer of thermal recording material on a support, and recorded a deformation pattern in said thermal recording material by exposure to radiation, said thermal recording material in a first form being absorbant to radiation of a selected wavelength for recording of said deformation pattern, the improvement comprising the steps of:

altering the spectral absorption characteristics of said thermal recording material to render it significantly less absorbant to radiation of the wavelength or wavelengths of said exposing radiation.

25. In an improved method as claimed in claim 24 wherein said thermal recording material includes a dye that, in an unaltered form, is absorbant to said exposing radiation, the improvement wherein said dye is altered by bleaching to a form significantly less absorbant to radiation of the wavelength or wavelengths of said exposing radiation.

26. A method as claimed in claim 25 wherein said dye is bleached by a photobleaching process.

27. A method as claimed in claim 25 wherein said dye is bleached by a thermal bleaching process.

28. A method as claimed in claim 25 wherein said dye is bleached by a chemical bleaching process.

29. A method of recording and playing back information in the form of deformations in a layer of thermal recording material, which recording material in a first condition is absorbant to radiation of a predetermined wavelength range, and which recording material in a second condition is less absorbant to radiation within said wavelength range, said method comprising the steps of:

a. recording information in the form of thermal deformations in said thermal recording material by selectively exposing said material to laser radiation having a wavelength with said wavelength range;

b. altering said thermal recording material from said first condition to said second condition to render it less absorbant to said recording radiation, and

c. illuminating said recorded deformations with radiation from said recording laser to develop a signal indicative of the recorded information without adversely affecting said recorded deformations.

30. A method as claimed in claim 29 further comprising the step of adjusting the power level of said illuminating radiation to maximize the signal-to-noise ratio of the recovered signal.

31. A method of recording and playing back information, said method comprising:

a. recording information in the form of discrete, light-scattering craters in a recording layer comprising a bleachable dye dispersed throughout a substantially-transparent, heat-deformable binder by selectively exposing said recording layer to a beam of laser radiation of a predetermined power and of a predetermined wavelength to which said dye is highly absorptive;

b. bleaching said dye to render it substantially less absorptive to said predetermined wavelength; and

c. scanning the light-scattering radiation with a beam of laser radiation of said predetermined wavelength.

32. A high information density record device comprising a support having a light reflective surface and a recording layer overlying said surface, said recording layer comprising a dye-binder mixture wherein the dye has been bleached from a state of relatively high absorption to radiation of a predetermined wavelength to a state of relative transparency to radiation of said predetermined wavelength and having therein a plurality of discrete light-scattering craters formed by selective exposure of said layer to light of said predetermined wavelength.