JPS57198553A - Information processor - Google Patents

Information processor

Info

Publication number
JPS57198553A
JPS57198553A JP8663582A JP8663582A JPS57198553A JP S57198553 A JPS57198553 A JP S57198553A JP 8663582 A JP8663582 A JP 8663582A JP 8663582 A JP8663582 A JP 8663582A JP S57198553 A JPS57198553 A JP S57198553A
Authority
JP
Japan
Prior art keywords
semiconductor laser
photodetectors
self
distance
coupling effect
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.)
Pending
Application number
JP8663582A
Other languages
Japanese (ja)
Inventor
Yoshito Tsunoda
Toshimitsu Miyauchi
Ryoichi Ito
Kunio Aiki
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.)
Hitachi Ltd
Original Assignee
Hitachi 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
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP8663582A priority Critical patent/JPS57198553A/en
Publication of JPS57198553A publication Critical patent/JPS57198553A/en
Pending 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
    • 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

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

PURPOSE:To obtain both an information and a focus error signal, by providing three semiconductor lasers which differ in distance from a light emission point to a recording medium and have self-coupling effect. CONSTITUTION:The quantity of return light of laser luminous flux to a semiconductor laser varies with a spot diameter on a disk, so the quantity of the output light of the semiconductor laser varies and photodetectors 7a, 7b and 7c near an opening end on the opposite side of the semiconductor laser detect variation in output light due to self-coupling effect. Outputs of the photodetectors 7a, 7b and 7c are led to a differential amplifier 11 to perform automatic focusing. Semiconductor lasers 1a-1c are arranged differing in distance from a disk surface and spots 15a-15c on the disk surface have different diameters.
JP8663582A 1982-05-24 1982-05-24 Information processor Pending JPS57198553A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8663582A JPS57198553A (en) 1982-05-24 1982-05-24 Information processor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8663582A JPS57198553A (en) 1982-05-24 1982-05-24 Information processor

Publications (1)

Publication Number Publication Date
JPS57198553A true JPS57198553A (en) 1982-12-06

Family

ID=13892476

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8663582A Pending JPS57198553A (en) 1982-05-24 1982-05-24 Information processor

Country Status (1)

Country Link
JP (1) JPS57198553A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60171644A (en) * 1984-02-17 1985-09-05 Mitsubishi Electric Corp Focus deviation detecting device of light disk head
JPS61941A (en) * 1984-06-13 1986-01-06 Matsushita Electric Ind Co Ltd Semiconductor laser light pickup device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54108602A (en) * 1978-02-14 1979-08-25 Toshiba Corp Optical reproducer

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54108602A (en) * 1978-02-14 1979-08-25 Toshiba Corp Optical reproducer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60171644A (en) * 1984-02-17 1985-09-05 Mitsubishi Electric Corp Focus deviation detecting device of light disk head
JPS61941A (en) * 1984-06-13 1986-01-06 Matsushita Electric Ind Co Ltd Semiconductor laser light pickup device

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