JPS55129940A - Optical type reproducing device - Google Patents

Optical type reproducing device

Info

Publication number
JPS55129940A
JPS55129940A JP3478379A JP3478379A JPS55129940A JP S55129940 A JPS55129940 A JP S55129940A JP 3478379 A JP3478379 A JP 3478379A JP 3478379 A JP3478379 A JP 3478379A JP S55129940 A JPS55129940 A JP S55129940A
Authority
JP
Japan
Prior art keywords
light
lens
focusing
disc
read
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
JP3478379A
Other languages
Japanese (ja)
Inventor
Yoshihiro Uchiumi
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.)
Teac Corp
Original Assignee
Teac Corp
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 Teac Corp filed Critical Teac Corp
Priority to JP3478379A priority Critical patent/JPS55129940A/en
Publication of JPS55129940A publication Critical patent/JPS55129940A/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
    • 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
    • G11B7/0946—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 specially adapted for operation during external perturbations not related to the carrier or servo beam, e.g. vibration

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Moving Of The Head For Recording And Reproducing By Optical Means (AREA)

Abstract

PURPOSE:To perform accurate focusing with a simple constitution using a read beam, by not only receiving the read reproducing light by plural photo detection element to control the focus of an optical system but also preventing a false focusing state. CONSTITUTION:The light from light source 16 of read head 30 is irradiated to disc 11 through objective lens 22. Then, the read reproducing light is received by three sets of photo detection elements 39a, 39b and 39c. Light receiving detection signals dependent upon the light spot formed in these elements 39a, 39b and 39c are different from one another according to the focusing state of lens 22, and focusing of lens 22 is controlled through focus control circuit 1 by moving coil 26. Meanwhile, when the distance between lens 22 and disc 11 becomes large due to vibration, etc., of disc 11 and lens 22 becomes a false focusing state where detection outputs of elements 39a, 39b and 39c are in-phase, the output of element 39b becomes small, and switch 2 is closed by comparator circuit 4, and lock to the false focusing state is prevented with a simple constitution requiring no light beam only for focusing.
JP3478379A 1979-03-23 1979-03-23 Optical type reproducing device Pending JPS55129940A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP3478379A JPS55129940A (en) 1979-03-23 1979-03-23 Optical type reproducing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3478379A JPS55129940A (en) 1979-03-23 1979-03-23 Optical type reproducing device

Publications (1)

Publication Number Publication Date
JPS55129940A true JPS55129940A (en) 1980-10-08

Family

ID=12423869

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3478379A Pending JPS55129940A (en) 1979-03-23 1979-03-23 Optical type reproducing device

Country Status (1)

Country Link
JP (1) JPS55129940A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4507766A (en) * 1981-07-16 1985-03-26 Matsushita Electric Industrial Co., Ltd. Optical device for optically recording and reproducing information signals on an information carrier

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4507766A (en) * 1981-07-16 1985-03-26 Matsushita Electric Industrial Co., Ltd. Optical device for optically recording and reproducing information signals on an information carrier

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