FI921879A0 - FOKUSREGLERINGSKRETS. - Google Patents
FOKUSREGLERINGSKRETS.Info
- Publication number
- FI921879A0 FI921879A0 FI921879A FI921879A FI921879A0 FI 921879 A0 FI921879 A0 FI 921879A0 FI 921879 A FI921879 A FI 921879A FI 921879 A FI921879 A FI 921879A FI 921879 A0 FI921879 A0 FI 921879A0
- Authority
- FI
- Finland
- Prior art keywords
- focussing
- recording medium
- control loop
- signal
- photodiodes
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0908—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only
- G11B7/0909—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following for focusing only by astigmatic methods
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/094—Methods and circuits for servo offset compensation
Landscapes
- Optical Recording Or Reproduction (AREA)
- Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
- Medicines Containing Plant Substances (AREA)
- Medicines Containing Material From Animals Or Micro-Organisms (AREA)
- Ignition Installations For Internal Combustion Engines (AREA)
- Looms (AREA)
- Focusing (AREA)
- Automatic Focus Adjustment (AREA)
- Telescopes (AREA)
- Details Of Television Scanning (AREA)
- Eye Examination Apparatus (AREA)
- Lubrication Of Internal Combustion Engines (AREA)
Abstract
The invention concerns an optical scanning device which scans the frequency-warbled data tracks of a recording medium, the scanning light beam being reflected from the recording medium on to a four-quadrant photodetector (PD) with four photodiodes (A, B, C, D). In order to be able to compensate automatically for offset voltages produced in the focussing-control loop by, for instance, temperature fluctuations, the focussing signal and the track error signal are input into a multiplier circuit (M). The multiplier output is fed through a low-pass filter (TP) and as a compensation voltage to the focussing-control loop.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE3936032A DE3936032A1 (en) | 1989-10-28 | 1989-10-28 | FOCUS CONTROL |
PCT/EP1990/001603 WO1991006949A1 (en) | 1989-10-28 | 1990-09-21 | Automatic focussing control |
Publications (2)
Publication Number | Publication Date |
---|---|
FI921879A0 true FI921879A0 (en) | 1992-04-27 |
FI921879A FI921879A (en) | 1992-04-27 |
Family
ID=6392483
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FI921879A FI921879A (en) | 1989-10-28 | 1992-04-27 | FOKUSREGLERINGSKRETS. |
Country Status (14)
Country | Link |
---|---|
EP (1) | EP0500547B1 (en) |
JP (1) | JP2930715B2 (en) |
KR (1) | KR100251289B1 (en) |
CN (1) | CN1022518C (en) |
AT (1) | ATE114381T1 (en) |
AU (1) | AU6405190A (en) |
DE (2) | DE3936032A1 (en) |
ES (1) | ES2064763T3 (en) |
FI (1) | FI921879A (en) |
HK (1) | HK68795A (en) |
HU (1) | HU208588B (en) |
MY (1) | MY107278A (en) |
TR (1) | TR24658A (en) |
WO (1) | WO1991006949A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5978329A (en) * | 1995-06-07 | 1999-11-02 | Discovision Associates | Technique for closed loop servo operation in optical disc tracking control |
WO2002093568A1 (en) * | 2001-05-11 | 2002-11-21 | Matsushita Electric Industrial Co., Ltd. | Optical head, disc recording/reproducing apparatus, and objective lens drive method |
DE102005018461A1 (en) * | 2005-04-20 | 2006-10-26 | Deutsche Thomson-Brandt Gmbh | Focus control for optical scanner |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6070923U (en) * | 1983-10-19 | 1985-05-20 | パイオニア株式会社 | Focus error detection device |
JPS61269241A (en) * | 1985-05-24 | 1986-11-28 | Sony Corp | Focus detecting device for optical head |
-
1989
- 1989-10-28 DE DE3936032A patent/DE3936032A1/en not_active Withdrawn
-
1990
- 1990-09-21 EP EP90913816A patent/EP0500547B1/en not_active Expired - Lifetime
- 1990-09-21 DE DE59007781T patent/DE59007781D1/en not_active Expired - Fee Related
- 1990-09-21 ES ES90913816T patent/ES2064763T3/en not_active Expired - Lifetime
- 1990-09-21 AT AT90913816T patent/ATE114381T1/en active
- 1990-09-21 JP JP2512856A patent/JP2930715B2/en not_active Expired - Fee Related
- 1990-09-21 KR KR1019920700988A patent/KR100251289B1/en not_active IP Right Cessation
- 1990-09-21 AU AU64051/90A patent/AU6405190A/en not_active Abandoned
- 1990-09-21 WO PCT/EP1990/001603 patent/WO1991006949A1/en active IP Right Grant
- 1990-09-21 HU HU921300A patent/HU208588B/en not_active IP Right Cessation
- 1990-10-23 MY MYPI90001852A patent/MY107278A/en unknown
- 1990-10-26 TR TR90/1013A patent/TR24658A/en unknown
- 1990-10-27 CN CN90108670A patent/CN1022518C/en not_active Expired - Fee Related
-
1992
- 1992-04-27 FI FI921879A patent/FI921879A/en not_active Application Discontinuation
-
1995
- 1995-05-04 HK HK68795A patent/HK68795A/en not_active IP Right Cessation
Also Published As
Publication number | Publication date |
---|---|
HUT60874A (en) | 1992-10-28 |
JPH05501327A (en) | 1993-03-11 |
ES2064763T3 (en) | 1995-02-01 |
DE59007781D1 (en) | 1995-01-05 |
ATE114381T1 (en) | 1994-12-15 |
MY107278A (en) | 1995-10-31 |
DE3936032A1 (en) | 1991-05-02 |
HK68795A (en) | 1995-05-12 |
CN1051444A (en) | 1991-05-15 |
HU9201300D0 (en) | 1992-07-28 |
KR920704282A (en) | 1992-12-19 |
TR24658A (en) | 1992-03-01 |
EP0500547A1 (en) | 1992-09-02 |
AU6405190A (en) | 1991-05-31 |
EP0500547B1 (en) | 1994-11-23 |
KR100251289B1 (en) | 2000-04-15 |
WO1991006949A1 (en) | 1991-05-16 |
CN1022518C (en) | 1993-10-20 |
JP2930715B2 (en) | 1999-08-03 |
FI921879A (en) | 1992-04-27 |
HU208588B (en) | 1993-11-29 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
FD | Application lapsed |