GB2057218B - Detecting focussing error - Google Patents

Detecting focussing error

Info

Publication number
GB2057218B
GB2057218B GB8020097A GB8020097A GB2057218B GB 2057218 B GB2057218 B GB 2057218B GB 8020097 A GB8020097 A GB 8020097A GB 8020097 A GB8020097 A GB 8020097A GB 2057218 B GB2057218 B GB 2057218B
Authority
GB
United Kingdom
Prior art keywords
focussing error
detecting focussing
detecting
error
focussing
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.)
Expired
Application number
GB8020097A
Other versions
GB2057218A (en
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.)
Olympus Corp
Original Assignee
Olympus Corp
Olympus Optical Co Ltd
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
Priority claimed from JP7994379A external-priority patent/JPS567246A/en
Priority claimed from JP13699679A external-priority patent/JPS5661044A/en
Application filed by Olympus Corp, Olympus Optical Co Ltd filed Critical Olympus Corp
Publication of GB2057218A publication Critical patent/GB2057218A/en
Application granted granted Critical
Publication of GB2057218B publication Critical patent/GB2057218B/en
Expired 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
    • 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
    • G11B7/12—Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • 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
    • G11B2007/0924—Skewed beams methods (using an angled beam, i.e. a beam which is reflected from the disc at an angle different from 90°)
GB8020097A 1979-06-25 1980-06-19 Detecting focussing error Expired GB2057218B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP7994379A JPS567246A (en) 1979-06-25 1979-06-25 Method and unit for focus detection
JP13699679A JPS5661044A (en) 1979-10-25 1979-10-25 Optical information reader

Publications (2)

Publication Number Publication Date
GB2057218A GB2057218A (en) 1981-03-25
GB2057218B true GB2057218B (en) 1984-02-29

Family

ID=33133247

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8020097A Expired GB2057218B (en) 1979-06-25 1980-06-19 Detecting focussing error

Country Status (4)

Country Link
DE (1) DE3023779A1 (en)
FR (1) FR2459991A1 (en)
GB (1) GB2057218B (en)
NL (1) NL192406C (en)

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5752006A (en) * 1980-08-19 1982-03-27 Olympus Optical Co Ltd Method and device for detecting focus
JPS5752005A (en) * 1980-08-19 1982-03-27 Olympus Optical Co Ltd Focus detecting method
JPS5744236A (en) * 1980-08-29 1982-03-12 Matsushita Electric Ind Co Ltd Optical information reproducer
JPS5774837A (en) * 1980-10-25 1982-05-11 Olympus Optical Co Ltd Signal detection system of optical information reproducing device
US4505584A (en) * 1981-01-22 1985-03-19 Olympus Optical Co., Ltd. Method and apparatus for detecting focussing error signal of objective lens
JPS57189348A (en) * 1981-05-14 1982-11-20 Olympus Optical Co Ltd Auto-focus system of optical disk
DE3280232D1 (en) * 1981-06-22 1990-09-27 Toshiba Kawasaki Kk OPTICAL HEAD.
EP0075192B1 (en) * 1981-09-17 1990-03-14 Kabushiki Kaisha Toshiba An optical head
DE3363889D1 (en) * 1982-03-19 1986-07-10 Olympus Optical Co Focus state detector
GB2122835B (en) * 1982-06-30 1986-08-06 Eastman Kodak Co Rangefinder
JPS5936338A (en) * 1982-08-24 1984-02-28 Matsushita Electric Ind Co Ltd Optical disk recording and reproducing method
GB2135150A (en) * 1983-02-15 1984-08-22 Gen Electric Optical inspection system
JPS59162514A (en) * 1983-03-08 1984-09-13 Dainippon Screen Mfg Co Ltd Focus adjusting method of image scanning and recording device
JPS61105736A (en) * 1984-10-29 1986-05-23 Pioneer Electronic Corp Focus controller
US4778984A (en) * 1985-10-16 1988-10-18 Canon Denshi Kabushiki Kaisha Apparatus for detecting focus from astigmatism
HU201403B (en) * 1987-06-05 1990-10-28 Videoton Elekt Vallalat Process and device for determining diameter of light beams
US5202789A (en) * 1987-10-16 1993-04-13 Kabushiki Kaisha Toshiba Optical system for preserving a state of polarization of light beam
JP2603973B2 (en) * 1987-10-16 1997-04-23 株式会社東芝 Optical head
EP0439876A1 (en) * 1990-01-29 1991-08-07 Hitachi Maxell Ltd. Optical head with a double-beam splitter

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2260474C3 (en) * 1972-12-11 1981-10-08 Ernst Leitz Wetzlar Gmbh, 6330 Wetzlar Method and device for focusing a lens
GB1603596A (en) * 1977-06-06 1981-11-25 Mca Disco Vision Optical transducer and focusing system

Also Published As

Publication number Publication date
NL192406B (en) 1997-03-03
DE3023779C2 (en) 1987-01-22
FR2459991B1 (en) 1984-11-30
NL8003659A (en) 1980-12-30
FR2459991A1 (en) 1981-01-16
DE3023779A1 (en) 1981-02-05
NL192406C (en) 1997-07-04
GB2057218A (en) 1981-03-25

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19990619