JPS5613532A - Focus detector of optical information reproducing device - Google Patents

Focus detector of optical information reproducing device

Info

Publication number
JPS5613532A
JPS5613532A JP8998379A JP8998379A JPS5613532A JP S5613532 A JPS5613532 A JP S5613532A JP 8998379 A JP8998379 A JP 8998379A JP 8998379 A JP8998379 A JP 8998379A JP S5613532 A JPS5613532 A JP S5613532A
Authority
JP
Japan
Prior art keywords
prism
photodetectors
constitution
ray
slit
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
JP8998379A
Other languages
Japanese (ja)
Inventor
Yasuo Hachi
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.)
Victor Company of Japan Ltd
Original Assignee
Victor Company of Japan 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 Victor Company of Japan Ltd filed Critical Victor Company of Japan Ltd
Priority to JP8998379A priority Critical patent/JPS5613532A/en
Publication of JPS5613532A publication Critical patent/JPS5613532A/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

Landscapes

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

Abstract

PURPOSE:To obtain a device of easily-assembled constitution that uses components requiring precision, by leading halves of a ray of reflected light from a recording medium to the 1st and 2nd photodetectors by way of a fixed surface of a prism, a slit, etc. CONSTITUTION:Half 9B of reflected laser light ray 9 from disk 1, etc., enters prism 10 from refraction surface 10b slanting to surface 10a perpendicular to the optical axis of prism 10 having focusing point P inside and is detected by the 1st photodetector 14a. The other half of ray 9, on the other hand, enters prism 10 from surface 10a of prism 10 and is led to the 2nd photodetector 14b by way of a slit formed of slit member 13 and only in focusing, the quantities of photodetected light of both photodetectors 14a and 14b become equal, so that differential amplifier 15 provides focus detection with high precision. In this constitution, accuracy is not required in terms of the prism and its arrangement, arrangement of photodetectors when two photodetectors are used, etc., and the detectors can easily be assembled by using components which does not require precision.
JP8998379A 1979-07-16 1979-07-16 Focus detector of optical information reproducing device Pending JPS5613532A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8998379A JPS5613532A (en) 1979-07-16 1979-07-16 Focus detector of optical information reproducing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8998379A JPS5613532A (en) 1979-07-16 1979-07-16 Focus detector of optical information reproducing device

Publications (1)

Publication Number Publication Date
JPS5613532A true JPS5613532A (en) 1981-02-09

Family

ID=13985886

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8998379A Pending JPS5613532A (en) 1979-07-16 1979-07-16 Focus detector of optical information reproducing device

Country Status (1)

Country Link
JP (1) JPS5613532A (en)

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