FR2393362A1 - Focussing control for optical recording system - uses outputs of two photodetectors receiving respective partially-reflected beams from semi-reflective mirror - Google Patents

Focussing control for optical recording system - uses outputs of two photodetectors receiving respective partially-reflected beams from semi-reflective mirror

Info

Publication number
FR2393362A1
FR2393362A1 FR7816656A FR7816656A FR2393362A1 FR 2393362 A1 FR2393362 A1 FR 2393362A1 FR 7816656 A FR7816656 A FR 7816656A FR 7816656 A FR7816656 A FR 7816656A FR 2393362 A1 FR2393362 A1 FR 2393362A1
Authority
FR
France
Prior art keywords
semi
reflective mirror
optical recording
recording system
reflected beams
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.)
Withdrawn
Application number
FR7816656A
Other languages
French (fr)
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.)
Robert Bosch GmbH
Original Assignee
Robert Bosch 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 Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of FR2393362A1 publication Critical patent/FR2393362A1/en
Withdrawn legal-status Critical Current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
    • G11B7/0917—Focus-error methods other than those covered by G11B7/0909 - G11B7/0916
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/24—Base structure
    • G02B21/26—Stages; Adjusting means therefor
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G02B7/30—Systems for automatic generation of focusing signals using parallactic triangle with a base line
    • G02B7/32—Systems for automatic generation of focusing signals using parallactic triangle with a base line using active means, e.g. light emitter
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

The optical data storage system uses a laser beam (2) directed via a semi-reflective mirror (3), an afocal optical system (4) and a lens (5) onto the recording surface (6). Light reflected back from the latter along the same path is deflected by the semi-reflective mirror (3) at an angle to the original optical path. The deflected light passes via a shutter (9) and a converging lens (10) to a beam splitter, with each partial beam falling onto a photodetector (12a, 12b). The outputs of the two photodetectors (12a, 12b) are subtracted from one another and the resultant is amplified and used as a focussing control signal for varying the distance of the lens (5) from the recording surface (6).
FR7816656A 1977-06-02 1978-06-02 Focussing control for optical recording system - uses outputs of two photodetectors receiving respective partially-reflected beams from semi-reflective mirror Withdrawn FR2393362A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19772724876 DE2724876A1 (en) 1977-06-02 1977-06-02 SYSTEM FOR AUTOMATIC, CONTACTLESS DISTANCE REGULATION WITH OPTICAL SIGNAL RECORDING OR -REPRODUCTION

Publications (1)

Publication Number Publication Date
FR2393362A1 true FR2393362A1 (en) 1978-12-29

Family

ID=6010506

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7816656A Withdrawn FR2393362A1 (en) 1977-06-02 1978-06-02 Focussing control for optical recording system - uses outputs of two photodetectors receiving respective partially-reflected beams from semi-reflective mirror

Country Status (2)

Country Link
DE (1) DE2724876A1 (en)
FR (1) FR2393362A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2422219A1 (en) * 1978-04-07 1979-11-02 Hitachi Ltd INFORMATION RECORDING DEVICE

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59232333A (en) * 1983-06-15 1984-12-27 Fuji Photo Film Co Ltd Automatic focus setting method
DE3924290A1 (en) * 1989-07-22 1991-01-31 Fraunhofer Ges Forschung Optical distance measurement arrangement with Fourier system - has position sensitive correction detector in correction arm of beam divider for correction of aperture intensity distribution errors

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2422219A1 (en) * 1978-04-07 1979-11-02 Hitachi Ltd INFORMATION RECORDING DEVICE

Also Published As

Publication number Publication date
DE2724876A1 (en) 1978-12-14

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Legal Events

Date Code Title Description
ST Notification of lapse