JPS5661043A - Detector for focus - Google Patents

Detector for focus

Info

Publication number
JPS5661043A
JPS5661043A JP13644479A JP13644479A JPS5661043A JP S5661043 A JPS5661043 A JP S5661043A JP 13644479 A JP13644479 A JP 13644479A JP 13644479 A JP13644479 A JP 13644479A JP S5661043 A JPS5661043 A JP S5661043A
Authority
JP
Japan
Prior art keywords
light
incident
prisms
location
prism
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
JP13644479A
Other languages
Japanese (ja)
Inventor
Kiichi Kato
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 JP13644479A priority Critical patent/JPS5661043A/en
Publication of JPS5661043A publication Critical patent/JPS5661043A/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

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

Abstract

PURPOSE:To simplify the constitution and to make small and light the device with less number of optical elements, by using a plurality of prisms consisting of plural refractive materials as optical path split prisms so that the incident and reflected light flux pass through the same optical elements. CONSTITUTION:The light from a light source 21 is made to a parallel light flux at a collimator lens 22, and it is incident to plural prisms, e.g., a Rochon prism 23. This light is the P polarized light component being normal light to the Rochon prism 23, it passes through along the light axis O and is incident to the information track of a recording medium 26 via a 1/4 wave length plate 24 and an objective lens 25. The light reflected at it is converted for the direction of polarization from P into S component at the 1/4 wave length plate 24. Accordingly, it is refracted at the Ronchon prism 23 and incident with a slope to the light axis O of the collimator lens 22 to form an image of photospot at a location different from the location of the light source 21. A four-split photodetector 27 is located at this location to obtain a focus error signal.
JP13644479A 1979-10-24 1979-10-24 Detector for focus Pending JPS5661043A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP13644479A JPS5661043A (en) 1979-10-24 1979-10-24 Detector for focus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP13644479A JPS5661043A (en) 1979-10-24 1979-10-24 Detector for focus

Publications (1)

Publication Number Publication Date
JPS5661043A true JPS5661043A (en) 1981-05-26

Family

ID=15175250

Family Applications (1)

Application Number Title Priority Date Filing Date
JP13644479A Pending JPS5661043A (en) 1979-10-24 1979-10-24 Detector for focus

Country Status (1)

Country Link
JP (1) JPS5661043A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5868246A (en) * 1981-10-19 1983-04-23 Hitachi Ltd Focus error detector
JPH07262600A (en) * 1995-02-27 1995-10-13 Canon Inc Optical head device
US5870370A (en) * 1993-09-24 1999-02-09 Ricoh Company, Ltd. Optical pickup apparatus
JP2010147481A (en) * 1998-03-30 2010-07-01 Toshiba Corp Noise reducing element, and semiconductor circuit element using the same

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5868246A (en) * 1981-10-19 1983-04-23 Hitachi Ltd Focus error detector
US5870370A (en) * 1993-09-24 1999-02-09 Ricoh Company, Ltd. Optical pickup apparatus
USRE40414E1 (en) * 1993-09-24 2008-07-01 Ricoh Company, Ltd. Optical pickup apparatus
JPH07262600A (en) * 1995-02-27 1995-10-13 Canon Inc Optical head device
JP2010147481A (en) * 1998-03-30 2010-07-01 Toshiba Corp Noise reducing element, and semiconductor circuit element using the same

Similar Documents

Publication Publication Date Title
JPS5753832A (en) Method and device for recording of optical information
US4998011A (en) Flat plate focus sensing apparatus
JPS5647933A (en) Optical signal head
JPS6227456B2 (en)
JPS5753831A (en) Method and device for reproduction of optical information
NL192406C (en) Device for detecting a focusing error signal for an objective lens when scanning an information carrier.
KR850001924B1 (en) The method and apparatus for detecting a focussing error signal of objective lens
JPS5752005A (en) Focus detecting method
JPS5661043A (en) Detector for focus
JPS57169947A (en) Magnetic optical head
JPS57149912A (en) Optical position detector
JPS5746334A (en) Optical information reproducer
JPS5766537A (en) Magnetooptic recording and reproducing device
US6249493B1 (en) Recording or replay device and method for recognition of a focussing status
JPS58199447A (en) Photodetector of optical reader
JPS5629847A (en) Optical type information recording and reproducing unit
JPS573236A (en) Optical information reader
SU1490661A1 (en) Device for recording and playback of information from disk magnetic carrier
KR850000421B1 (en) Forcus detecting method
SU451904A1 (en) Device for control of flatness of opaque parts
JPS54104303A (en) Optical system signal reading system
JPS6479944A (en) Optical pickup device
SU534674A1 (en) Device for measuring changes in the refractive index of transparent media
KR850000649Y1 (en) Forcus detecting device
JPS5733443A (en) Focus detector