JPS54134605A - Method and appartus of controlling focus - Google Patents

Method and appartus of controlling focus

Info

Publication number
JPS54134605A
JPS54134605A JP4207778A JP4207778A JPS54134605A JP S54134605 A JPS54134605 A JP S54134605A JP 4207778 A JP4207778 A JP 4207778A JP 4207778 A JP4207778 A JP 4207778A JP S54134605 A JPS54134605 A JP S54134605A
Authority
JP
Japan
Prior art keywords
luminous flux
video disc
focus
objective lens
disc face
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
JP4207778A
Other languages
Japanese (ja)
Other versions
JPS6038772B2 (en
Inventor
Kenichi Oikami
Shohei Nagai
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 JP53042077A priority Critical patent/JPS6038772B2/en
Priority to US05/940,660 priority patent/US4223348A/en
Publication of JPS54134605A publication Critical patent/JPS54134605A/en
Publication of JPS6038772B2 publication Critical patent/JPS6038772B2/en
Expired 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
    • G11B7/0909—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 by astigmatic methods

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)
  • Holo Graphy (AREA)
  • Optical Recording Or Reproduction (AREA)
  • Optical Head (AREA)

Abstract

PURPOSE:To perform focus controlling automatically by passing object luminous flux through the optical system having astignatism and coma aberration and focusing the same with astigmatism and coma aberration in the optical system of a video disc apparatus. CONSTITUTION:The astignatism of the light image of a focus controlling luminous flux 42 on a video disc face 49 is DELTAl/alpha if the magnification of an objective lens 48 is let to be alpha. The focus controlling luminous flux 42 reflected by the video disc face 49 passes through the objective lens 48 and tracking mirror 47 and is again image near relay lens focal plane 46. This luminous flux further passes through a relay lens 45 and becomes the nearly parallel luminous flux having the sectional shape resembling to that of the light image on the relay lens focal plane 46, i.e., the luminous flux having an extremely large astigmatism. This luminous flux is then focused on a focus detecting element 58 through a half mirror 44 and focusing lens 57. Here, the sectional shape of the luminous flux incident to the focus detecting element 58 changes according to the change of the distance between the objective lens 48 and video disc face 49.
JP53042077A 1977-09-12 1978-04-12 Focus adjustment method and device Expired JPS6038772B2 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP53042077A JPS6038772B2 (en) 1978-04-12 1978-04-12 Focus adjustment method and device
US05/940,660 US4223348A (en) 1977-09-12 1978-09-08 Automatic focussing device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP53042077A JPS6038772B2 (en) 1978-04-12 1978-04-12 Focus adjustment method and device

Publications (2)

Publication Number Publication Date
JPS54134605A true JPS54134605A (en) 1979-10-19
JPS6038772B2 JPS6038772B2 (en) 1985-09-03

Family

ID=12625987

Family Applications (1)

Application Number Title Priority Date Filing Date
JP53042077A Expired JPS6038772B2 (en) 1977-09-12 1978-04-12 Focus adjustment method and device

Country Status (1)

Country Link
JP (1) JPS6038772B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60135809A (en) * 1983-12-26 1985-07-19 Tokyo Optical Co Ltd Flaw detection apparatus
JPS6179663A (en) * 1984-09-28 1986-04-23 Hitachi Ltd Dot type printing machine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61192871U (en) * 1985-05-25 1986-12-01

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60135809A (en) * 1983-12-26 1985-07-19 Tokyo Optical Co Ltd Flaw detection apparatus
JPH041849B2 (en) * 1983-12-26 1992-01-14 Topcon Corp
JPS6179663A (en) * 1984-09-28 1986-04-23 Hitachi Ltd Dot type printing machine

Also Published As

Publication number Publication date
JPS6038772B2 (en) 1985-09-03

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