Method of controlling recording of optical records

• US 5,590,111 A
• Filed: 07/13/1993
• Issued: 12/31/1996
• Est. Priority Date: 06/29/1990
• Status: Expired due to Term

• Current Assignee: Hitachi Consumer Electronics Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Maeda, Takeshi, Ide, Hiroshi, Toda, Tsuyoshi, Kaku, Toshimitsu, Kirino, Fumiyoshi, Shigematsu, Kazuo, Mita, Seiichi
• Primary Examiner(s): Tran, Thai Q.
• Application Number:
  US08/091,003
• Time in Patent Office: 1,267 Days
• Field of Search: 369/116, 369/124, 369/121, 369/13, 369/100, 369/110, 369/54, 360/114, 358/342
• US Class Current: 369/47.53
• CPC Class Codes: G11B 11/10506 by modulating only the light beam of the transducer
• CPC Class Codes: G11B 11/10508 by modulating only the magnetic field at the transducer
• CPC Class Codes: G11B 11/1053 to compensate for the magnetic domain drift or time shift
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 20/10009 Improvement or modification of read or write signals
• CPC Class Codes: G11B 20/10212 compensation for data shift, e.g. pulse-crowding effects
• CPC Class Codes: G11B 20/1258 where blocks are arranged within multiple radial zones, e.g. Zone Bit Recording or Constant Density Recording discs, MCAV discs, MCLV discs
• CPC Class Codes: G11B 20/1816 Testing
• CPC Class Codes: G11B 7/0045 Recording G11B7/006, G11B7/0065 take precedence
• CPC Class Codes: G11B 7/126 Circuits, methods or arrangements for laser control or stabilisation
• CPC Class Codes: G11B 7/1267 Power calibration
• CPC Class Codes: G11B 7/24085 Pits

Abstract

In a write control method on an optical recording, at least one shift amount selected from the defocus amount of a laser beam on a recording medium, the shift amount of a recording position on a recording track and the shift amount of laser power during recording is controlled such that the selected amount falls within a predetermined range. Subsequently, a trial signal is trially recorded at a plurality of trial zones on the recording medium by using a laser power value as a parameter. The recorded trial signal is read and a difference ΔV between center levels of a highest density waveform and a lowest density waveform is detected. In connection with each trial zone, the laser power value when a reading trial signal which makes the difference ΔV minimum is recorded is defined as an optimum recording power value. Regular data is recorded at a predetermined storage area on the recording medium by using an optimum laser power value determined in connection with a trial zone closest to the predetermined storage area.

Claims

1. A control method of controlling recording and reproducing of optical records in an optical magnetic disk apparatus using a mark length recording method, comprising the steps of:

recording a predetermined test pattern on a recording medium;

reproducing said predetermined test pattern;

controlling at least one shift amount selected from a defocus amount of a laser beam on a recording medium, a position shift amount of a recording position on a track at which recording is performed on said recording medium and a power shift amount of laser power irradiated during recording, to reduce a distortion of the reproduced said predetermined test pattern to less than a first predetermined value;

obtaining control information under various environments in which optical recording and reproducing are performed, by repeating said steps of recording, reproducing said predetermined test patterns and controlling;

recording general data on said recording medium by setting an optimum pulse width or an optimum laser power for recording on a basis of said control information; and

reproducing said general data by subjecting a reproduced said general data to wave-equalizing processing, to reduce a distortion of said general data reproduced to less than a second predetermined value which is less than said first predetermined value.

2. A control method according to claim 1 wherein, in said controlling step, a characteristic to be controlled when recording and reading of said predetermined test pattern are performed is said defocus amount of a laser beam on said recording medium during recording of said test pattern, and said defocus amount is adjusted to ±

0.05 μ

m or less.

3. A control method according to claim 1 wherein, in said controlling step, a characteristic to be controlled when recording and reading of said predetermined test pattern are performed is said position shift amount of a recording position on a track at which recording is done on said recording medium, and said position shift amount is adjusted to ±

0.10 μ

m or less.

4. A control method according to claim 1 wherein, in said controlling step, a characteristic to be controlled when recording and reading of said predetermined test pattern are performed is said power shift amount of laser power irradiated on said recording medium during recording, and said power shift amount is adjusted to ±

0.20 mW or less.

5. A control method according to claim 1 wherein a system for providing information to an edge portion of an information recording pit is used as a system for recording said general data on said recording medium.

6. A control method according to claim 1 wherein for determination of said control information, a predetermined recording pattern is trially recorded in advance of recording, the recorded said predetermined recording pattern is reproduced, and a reproduced said predetermined recording pattern is compared with reference information stored in a predetermined table to determine said control information.

7. A control method according to claim 1 wherein a medium including a magnetic film having vertical magnetic anisotropy is used as said recording medium to perform recording in a direction of magnetization of said vertically magnetized film, and recorded information is reproduced by using a magneto-optical effect to thereby perform recording and reading, a shape of a magnetic domain to be formed in said recording medium being controlled to control a read-out signal waveform.

8. A control method according to claim 2, wherein said defocus amount is more specifically adjusted to ±

0.30 μ

m or less.

9. A control method according to claim 3, wherein said position shift amount is more specifically adjusted to ±

0.80 μ

m or less.

10. A control method according to claim 4, wherein said power shift amount is more specifically adjusted to ±

0.10 mW or less.