AU6405190A - Automatic focussing control - Google Patents

Automatic focussing control

Info

Publication number
AU6405190A
AU6405190A AU64051/90A AU6405190A AU6405190A AU 6405190 A AU6405190 A AU 6405190A AU 64051/90 A AU64051/90 A AU 64051/90A AU 6405190 A AU6405190 A AU 6405190A AU 6405190 A AU6405190 A AU 6405190A
Authority
AU
Australia
Prior art keywords
focussing
recording medium
control loop
automatic focussing
focussing control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
AU64051/90A
Inventor
Christian Buchler
Heinz-Jorg Schroder
Friedhelm Zucker
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Deutsche Thomson Brandt GmbH
Original Assignee
Deutsche Thomson Brandt GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Deutsche Thomson Brandt GmbH filed Critical Deutsche Thomson Brandt GmbH
Publication of AU6405190A publication Critical patent/AU6405190A/en
Abandoned legal-status Critical Current

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)
  • Medicines Containing Material From Animals Or Micro-Organisms (AREA)
  • Acyclic And Carbocyclic Compounds In Medicinal Compositions (AREA)
  • Medicines Containing Plant Substances (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Looms (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)
  • Eye Examination Apparatus (AREA)
  • Details Of Television Scanning (AREA)
  • Telescopes (AREA)
  • Focusing (AREA)
  • Automatic Focus Adjustment (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.
AU64051/90A 1989-10-28 1990-09-21 Automatic focussing control Abandoned AU6405190A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3936032A DE3936032A1 (en) 1989-10-28 1989-10-28 FOCUS CONTROL
DE3936032 1989-10-28

Publications (1)

Publication Number Publication Date
AU6405190A true AU6405190A (en) 1991-05-31

Family

ID=6392483

Family Applications (1)

Application Number Title Priority Date Filing Date
AU64051/90A Abandoned AU6405190A (en) 1989-10-28 1990-09-21 Automatic focussing control

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) FI921879A0 (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)

* Cited by examiner, † Cited by third party
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)

* Cited by examiner, † Cited by third party
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

Also Published As

Publication number Publication date
KR920704282A (en) 1992-12-19
EP0500547A1 (en) 1992-09-02
JPH05501327A (en) 1993-03-11
HU208588B (en) 1993-11-29
TR24658A (en) 1992-03-01
HU9201300D0 (en) 1992-07-28
CN1051444A (en) 1991-05-15
DE3936032A1 (en) 1991-05-02
FI921879A (en) 1992-04-27
DE59007781D1 (en) 1995-01-05
MY107278A (en) 1995-10-31
CN1022518C (en) 1993-10-20
KR100251289B1 (en) 2000-04-15
EP0500547B1 (en) 1994-11-23
FI921879A0 (en) 1992-04-27
ATE114381T1 (en) 1994-12-15
ES2064763T3 (en) 1995-02-01
HUT60874A (en) 1992-10-28
HK68795A (en) 1995-05-12
WO1991006949A1 (en) 1991-05-16
JP2930715B2 (en) 1999-08-03

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