Intensity of a light beam changed according to the length of a mark

• US 6,018,508 A
• Filed: 09/26/1997
• Issued: 01/25/2000
• Est. Priority Date: 09/27/1996
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Hasegawa, Hiroshi
• Primary Examiner(s): Cabeca, John W.
• Assistant Examiner(s): CHU, KIM KWOK
• Application Number:
  US08/938,997
• Time in Patent Office: 851 Days
• Field of Search: 369/124, 369/47, 369/116, 369/100, 369/59, 369/275.2, 369/107.13, 369/54
• US Class Current: 369/59.11
• CPC Class Codes: G11B 7/00454 involving phase-change effects
• CPC Class Codes: G11B 7/00557 involving phase-change media
• CPC Class Codes: G11B 7/006 Overwriting G11B7/0065 takes precedence
• CPC Class Codes: G11B 7/126 Circuits, methods or arrangements for laser control or stabilisation

Abstract

The present invention discloses an optical information recording method where a mark is formed on a recording medium by irradiating a light beam on the recording medium as pulses and recorded information is represented by the positions of the starting end and the finishing end of the mark, wherein the intensity of the light beam is changed according to the length of the mark and/or the pulse width of the light beam is reduced at least for the difference between the length of a mark to be formed and the length of a standard mark when the mark to be formed is shorter than the standard mark.

Claims

1. An optical information recording method comprising forming a mark on a recording medium by radiating a light beam on the recording medium in a form of a single pulse or a multi-pulse, the number of pulses of the multi-pulse being in accordance with a length of the mark, recorded information being represented by the positions of a starting end and a finishing end of the mark,

wherein an intensity of the single pulse or a head pulse of the multi-pulse is in accordance with the length of the mark.

2. An optical information recording method according to claim 1, wherein a width of the single pulse is in accordance with a width of the mark.

3. An optical information recording method according to claim 2, wherein the light beam between the pulses of the multi-pulse has an intensity lower than the intensity necessary for erasing the mark.

4. An optical information recording method according to claim 1, wherein a light beam for forming a mark having a length shorter than a standard mark includes the single pulse, the single pulse having a width according to a width of the mark.

5. An optical information recording method according to claim 1, wherein a light beam for forming a mark having a length shorter than the standard mark has an intensity lower than the intensity of a part of the light beam for forming a mark having a length longer than the standard mark.

6. An optical information recording method according to claim 1, wherein a light beam for forming a mark having a length longer than a standard mark has different intensities in the head and the tail of the light beam.

7. An optical information recording method according to claim 1, wherein the light beam after finishing the irradiation of a light beam of a single pulse or a multi-pulse has an intensity lower than the intensity necessary for erasing the mark.

8. An optical information recording method according to claim 1, wherein the recording medium comprises a medium having a phase-change type recording medium, and the mark is formed by changing the recording film from the crystalline to the amorphous by the heat of the light beam.

9. An optical information recording method according to claim 1, wherein the light beam for forming a shortest mark of a nT length (n is the natural number, and T is the recording window width) includes a light pulse beam of a P1 intensity, and

a light beam for forming a mark of a (n+1)T to (n+m)T (m>

1, and m is the natural number) length includes a head light pulse beam of a P2 intensity (P1<

P2) and subsequent light pulse beams of a P3 intensity (P1<

P3).

10. An optical information recording method according to claim 9, wherein the light beam includes an off-pulse.

11. An optical information recording method according to claim 9, wherein the head light pulse beam for forming the (n+1) length mark includes a light pulse beam of a P4 (P1<

P4, P4 ≠

P2) intensity.

12. An optical information recording method according to claim 9, wherein the light beam for forming the (n+1)T to (n+m)T length mark has a bottom power between the pulse beams set at a value lower than a predetermined erasing power.

13. An optical information recording method according to claim 12, wherein the light beam includes an off-pulse.

14. An optical information recording method according to claim 12, wherein the light beam for forming a (n+1) length mark includes a light pulse beam of a P4 intensity (P1<

P4, P4≠

P2).

15. An optical information recording method comprising forming a mark on a recording medium by radiating a light beam on the recording medium in a form of a single pulse or a multi-pulse, the number of pulses of the multi-pulse being in accordance with a length of the mark, recorded information being represented by the positions of the starting end and the finishing end of the mark,

wherein a pulse width of a single pulse or a head pulse of the multi-pulse is reduced by a value greater than a value corresponding to a difference between the length of a mark to be formed and the length of a standard mark, when the mark to be formed is shorter than the standard mark.

16. An optical information recording method according to claim 15, wherein a width of the single pulse is in accordance with a width of the mark.

17. An optical information recording method according to claim 16, wherein the light beam between the pulses of the multi-pulse has an intensity lower than the intensity necessary for erasing the mark.

18. An optical information recording method according to claim 15, wherein the light beam for forming a mark having a length shorter than the standard mark is a single pulse, the single pulse having a width according to a width of the mark.

19. An optical information recording method according to claim 15, wherein a light beam for forming a mark having a length shorter than the standard mark has an intensity lower than the intensity of a part of the light beam for forming a mark having a length longer than the standard mark.

20. An optical information recording method according to claim 15, wherein a light beam for forming a mark having a length longer than the standard mark has different intensities in the head and the tail of the light beam.

21. An optical information recording method according to claim 15, wherein the light beam after finishing the irradiation of a light beam of the single pulse or the multi-pulse has an intensity lower than the intensity necessary for erasing the mark.

22. An optical information recording method according to claim 15, wherein the recording medium comprises a medium having a phase-change type recording medium, and the mark is formed by changing the recording film from the crystalline to the amorphous by the heat of the light beam.

23. An optical information recording method according to claim 15, wherein the light beam for forming a shortest mark of a nT (n is the natural number, and T is the recording window width) is a single light pulse beam, the light beam for forming a (n+1)T to (n+m)T length mark comprises a head light pulse beam and subsequent light pulse beams, and the pulse width of the single light pulse beam having a width of the head light pulse beam shortened by shortening at least one of a front edge and a rear edge by predetermined amounts.

24. An optical information recording method according to claim 23, wherein the light beam for forming a nT length mark (n is the natural number, and T is the recording window width) includes a light pulse beam of a width having a P1 intensity, and the light beam for forming a (n+1) to (n+m)T length mark includes a head light pulse beam of a P1 intensity and subsequent light pulse beams of a P4 intensity of the amount larger than P1 by a predetermined amount Δ

P.

25. An optical information recording method according to claim 23, wherein the light beam includes an off-pulse.

26. An optical information recording method according to claim 23, wherein the light beam for forming a (n+1)T to (n+m)T mark has the bottom power between the pulse beams set at a value lower than a predetermined erasing power.

27. An optical information recording method according to claim 15, wherein the light beam for forming a shortest mark of a nT (n is the natural number, and T is the recording window width) is a single light pulse beam, the light beam for forming a (n+1)T to (n+m)T length mark comprises a head light pulse beam and subsequent light pulse beam, and the pulse width of the single light pulse beam and a head light pulse beam for forming a mark having a length longer than the standard mark having a width of the head light pulse beam shortened by shortening at least one of a front edge and a rear edge by predetermined amounts.

28. An optical information recording method according to claim 27, wherein the light beam for forming a nT length mark (n is the natural number, and T is the recording window width) includes a light pulse beam of a width having a P1 intensity, and the light beam for forming a (n+1) to (n+m)T length mark includes a head light pulse beam of a P1 intensity and subsequent light pulse beams of a P4 intensity of the amount larger than P1 by a predetermined amount Δ

P.

29. An optical information recording method according to claim 27, wherein the light beam includes an off-pulse for erasing the mark.

30. An optical information recording method according to claim 27, wherein the light beam for forming a (n+1)T to (n+m)T mark has the bottom power between the pulse beams set at a value lower than a predetermined erasing power.

31. An optical information recording method comprising forming a mark on a recording medium by radiating a light beam on the recording medium in a form of a single pulse or a multi-pulse, the number of pulses of the multi-pulse being in accordance with a length of the mark, recorded information being represented by the positions of a starting end and a finishing end of the mark,

wherein an intensity of the single pulse or a head pulse of the multi-pulse is in accordance with the length of the mark;

and

a pulse width of the single pulse or a head pulse of the multi-pulse is reduced by a value greater than a value corresponding to a difference between the length of a mark to be formed and the length of a standard mark, when the mark to be formed is shorter than the standard mark.

32. An optical information recording method according to claim 31, wherein a width of the single pulse is in accordance with a width of the mark.

33. An optical information recording method according to claim 32, wherein the light beam between the pulses of the multi-pulse has an intensity lower than the intensity necessary for erasing the mark.

34. An optical information recording method according to claim 31, wherein the light beam for forming a mark having a length shorter than the standard mark is a single pulse, the single pulse having a width according to a width of the mark.

35. An optical information recording method according to claim 31, wherein a light beam for forming a mark having a length shorter than the standard mark has an intensity lower than the intensity of a part of the light beam for forming a mark having a length longer than the standard mark.

36. An optical information recording method according to claim 31, wherein a light beam for forming a mark having a length longer than the standard mark has different intensities in the head and the tail of the light beam.

37. An optical information recording method according to claim 31, wherein the light beam after finishing the irradiation of a light beam of the single pulse or the multi-pulse has an intensity lower than the intensity necessary for erasing the mark.

38. An optical information recording method according to claim 31, wherein the recording medium comprises a medium having a phase-change type recording medium, and the mark is formed by changing the recording film from the crystalline to the amorphous by the heat of the light beam.

39. An optical information recording method comprising:

forming mark on a recording medium by radiating a light beam on the recording medium as pulses and representing recorded information by the positions of a starting end and a finishing end of the mark; and

changing the intensity of the light beam according to the length of the mark,

wherein a pulse width of the light beam is reduced for a width value more than the decrement of the light pulse width corresponding to a difference between the length of a mark to be formed and the length of a standard mark, when the mark to be formed is shorter than the standard mark.