JPS5738405A - Method and device for detection of focal point - Google Patents

Method and device for detection of focal point

Info

Publication number
JPS5738405A
JPS5738405A JP11446380A JP11446380A JPS5738405A JP S5738405 A JPS5738405 A JP S5738405A JP 11446380 A JP11446380 A JP 11446380A JP 11446380 A JP11446380 A JP 11446380A JP S5738405 A JPS5738405 A JP S5738405A
Authority
JP
Japan
Prior art keywords
reflected light
light
prism
reflected
miniature
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.)
Granted
Application number
JP11446380A
Other languages
Japanese (ja)
Other versions
JPS6343813B2 (en
Inventor
Toru Musha
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 JP11446380A priority Critical patent/JPS5738405A/en
Priority to KR1019810003016A priority patent/KR850000421B1/en
Publication of JPS5738405A publication Critical patent/JPS5738405A/en
Publication of JPS6343813B2 publication Critical patent/JPS6343813B2/ja
Granted legal-status Critical Current

Links

Classifications

    • 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)
  • Optical Head (AREA)
  • Automatic Focus Adjustment (AREA)

Abstract

PURPOSE:To obtain a miniature and accurate focal point detector, by making the reflected light of the beams condensed on a subject to be irradiated incident to an optical member having a reflective surface that is set at almost the critical angle to a beam in the reflected light flux and then detecting the change of light volume distribution of the transmitted light. CONSTITUTION:The polarized beams emitted from a light source 21 such as a laser beam, etc. are condensed on a disk 6 via a collimator lens 22, a polarizing prism 23 and a 1/4 wavelength plate 24. The reflected light goes backward and is reflected by the prism 23 to be made incident to a reflective surface 27a which is set at nearly the critical angle to a detecting prism 27 via a 90 deg. rotor 32. This reflected light is received at a photodetector 30; while the transmitted light is received at photodetectors 28A and 28B. The outputs of the detectors 28A and 28B apply a focus error signal respectively via a differential amplifier 29; while the outputs of the detectors 28A, 28B and 30 apply the information signals via an adder 31 respectively. In such way, a miniature and accurate focus detector can be obtained.
JP11446380A 1980-08-19 1980-08-19 Method and device for detection of focal point Granted JPS5738405A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP11446380A JPS5738405A (en) 1980-08-19 1980-08-19 Method and device for detection of focal point
KR1019810003016A KR850000421B1 (en) 1980-08-19 1981-08-19 Forcus detecting method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11446380A JPS5738405A (en) 1980-08-19 1980-08-19 Method and device for detection of focal point

Publications (2)

Publication Number Publication Date
JPS5738405A true JPS5738405A (en) 1982-03-03
JPS6343813B2 JPS6343813B2 (en) 1988-09-01

Family

ID=14638361

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11446380A Granted JPS5738405A (en) 1980-08-19 1980-08-19 Method and device for detection of focal point

Country Status (2)

Country Link
JP (1) JPS5738405A (en)
KR (1) KR850000421B1 (en)

Also Published As

Publication number Publication date
JPS6343813B2 (en) 1988-09-01
KR830006707A (en) 1983-10-06
KR850000421B1 (en) 1985-03-26

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