JPS5738404A - Method and device for detection of focal point - Google Patents

Method and device for detection of focal point

Info

Publication number
JPS5738404A
JPS5738404A JP11445880A JP11445880A JPS5738404A JP S5738404 A JPS5738404 A JP S5738404A JP 11445880 A JP11445880 A JP 11445880A JP 11445880 A JP11445880 A JP 11445880A JP S5738404 A JPS5738404 A JP S5738404A
Authority
JP
Japan
Prior art keywords
reflected light
reflected
light
detecting
critical angle
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
JP11445880A
Other languages
Japanese (ja)
Inventor
Kiyozo Koshiishi
Asao Hayashi
Kenichi Oikami
Masatoshi Ida
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 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
Application filed by Olympus Optical Co Ltd filed Critical Olympus Optical Co Ltd
Priority to JP11445880A priority Critical patent/JPS5738404A/en
Priority to KR1019810003017A priority patent/KR830006708A/en
Publication of JPS5738404A publication Critical patent/JPS5738404A/en
Priority to KR2019850001878U priority patent/KR850000649Y1/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
    • 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)
  • Optical Recording Or Reproduction (AREA)
  • Automatic Focus Adjustment (AREA)

Abstract

PURPOSE:To increase the S/N, by making the reflected light of the beams focused on a subject to be irradiated incident to >=2 optical materials having a reflective surface that is set at almost at the critical angle to >=2 different beams in the reflected light flux and then detecting the change of the light volume distributions of both the reflected light and the transmitted light. CONSTITUTION:The P polarized beams emitted from a light source 21 such as a laser diode, etc. are condensed on a disk 6 via a collimator lens 22, a polarizing prism 23, a 1/4 wavelength plate 24 and an objective lens 25 respectively. The reflected light goes bsckward and is reflected by the prism 23 to be reflected on the reflective surfaces of detecting prisms 27A and 27B that are set almost equal to the critical angle to the reflected light. This reflected light is made incident to photodetectors 28A and 28B, and at the same time a part of it is made incident to a photodetector 28C. The outputs of the detectors 28A and 28B apply a focus error signal 30 via a differential amplifier 29; while the output of the detector 28C applies an information signal 32 via an amplifier 31. As a result, the S/N can be increased.
JP11445880A 1980-08-19 1980-08-19 Method and device for detection of focal point Pending JPS5738404A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP11445880A JPS5738404A (en) 1980-08-19 1980-08-19 Method and device for detection of focal point
KR1019810003017A KR830006708A (en) 1980-08-19 1981-08-19 Focus detection method and device
KR2019850001878U KR850000649Y1 (en) 1980-08-19 1985-02-25 Forcus detecting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11445880A JPS5738404A (en) 1980-08-19 1980-08-19 Method and device for detection of focal point

Publications (1)

Publication Number Publication Date
JPS5738404A true JPS5738404A (en) 1982-03-03

Family

ID=14638229

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11445880A Pending JPS5738404A (en) 1980-08-19 1980-08-19 Method and device for detection of focal point

Country Status (2)

Country Link
JP (1) JPS5738404A (en)
KR (1) KR830006708A (en)

Also Published As

Publication number Publication date
KR830006708A (en) 1983-10-06

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