FR2251021A1 - Automatic focussing system for laser beam on to moving object - has out of focus detector of beam of surface producing signal in feedback to correct - Google Patents

Automatic focussing system for laser beam on to moving object - has out of focus detector of beam of surface producing signal in feedback to correct

Info

Publication number
FR2251021A1
FR2251021A1 FR7439468A FR7439468A FR2251021A1 FR 2251021 A1 FR2251021 A1 FR 2251021A1 FR 7439468 A FR7439468 A FR 7439468A FR 7439468 A FR7439468 A FR 7439468A FR 2251021 A1 FR2251021 A1 FR 2251021A1
Authority
FR
France
Prior art keywords
moving object
optical system
feedback
correct
automatic focussing
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
FR7439468A
Other languages
French (fr)
Other versions
FR2251021B1 (en
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.)
Hitachi Ltd
Original Assignee
Hitachi 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
Priority claimed from JP12539573A external-priority patent/JPS5078340A/ja
Priority claimed from JP3796674A external-priority patent/JPS50132939A/ja
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Publication of FR2251021A1 publication Critical patent/FR2251021A1/en
Application granted granted Critical
Publication of FR2251021B1 publication Critical patent/FR2251021B1/fr
Granted 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
    • G11B7/0917—Focus-error methods other than those covered by G11B7/0909 - G11B7/0916
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/40—Optical focusing aids
    • 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

Abstract

An automatic focussing system with a light source and an optical system. The light from the laser source (31) is focussed onto the measuring surface (36) of the moving object (6). There is an optical detector (38) on which the light that is either transmitted or reflected by the object is focussed by the optical system. Any out of focus of the optical system is detected to generate a signal which is fed back to the control circuit. The defocussing causes oscillation about the optical axis at a certain frequency. These signals and those of the optical system are both fed to a synchronising rectifier of the same frequency components to detect the extent of defocussing as a function of the modules value of the output.
FR7439468A 1973-11-09 1974-12-03 Automatic focussing system for laser beam on to moving object - has out of focus detector of beam of surface producing signal in feedback to correct Granted FR2251021A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP12539573A JPS5078340A (en) 1973-11-09 1973-11-09
JP3796674A JPS50132939A (en) 1974-04-05 1974-04-05

Publications (2)

Publication Number Publication Date
FR2251021A1 true FR2251021A1 (en) 1975-06-06
FR2251021B1 FR2251021B1 (en) 1979-06-08

Family

ID=26377151

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7439468A Granted FR2251021A1 (en) 1973-11-09 1974-12-03 Automatic focussing system for laser beam on to moving object - has out of focus detector of beam of surface producing signal in feedback to correct

Country Status (3)

Country Link
DE (1) DE2453364C3 (en)
FR (1) FR2251021A1 (en)
NL (1) NL7414695A (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2336766A1 (en) * 1975-12-26 1977-07-22 Sony Corp RECORDING MEDIA, ITS MANUFACTURING AND APPLICATION
FR2338543A1 (en) * 1976-01-16 1977-08-12 Philips Nv AUTOMATIC OPTICAL FOCUSING SYSTEM
FR2422219A1 (en) * 1978-04-07 1979-11-02 Hitachi Ltd INFORMATION RECORDING DEVICE
EP0021510A1 (en) * 1979-06-18 1981-01-07 Koninklijke Philips Electronics N.V. Optical scanning apparatus with focussing system
WO2012075013A1 (en) * 2010-11-30 2012-06-07 Johnson & Johnson Vision Care, Inc. Laser confocal sensor metrology system
US8810784B2 (en) 2012-02-10 2014-08-19 Johnson & Johnson Vision Care Inc. Method and apparatus for determining a thickness profile of an ophthalmic lens using a single point thickness and refractive index measurements

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS52120805A (en) * 1976-04-02 1977-10-11 Sony Corp Servo apparatus
GB1603596A (en) * 1977-06-06 1981-11-25 Mca Disco Vision Optical transducer and focusing system
JPS6053943B2 (en) * 1978-11-30 1985-11-28 キヤノン株式会社 Camera focus detection device
JPS6030015B2 (en) * 1979-05-09 1985-07-13 株式会社日立製作所 Light beam position control device
JPS5793307A (en) * 1980-12-02 1982-06-10 Olympus Optical Co Ltd Automatic focusing system
DE3913229A1 (en) * 1988-09-19 1990-03-22 Pioneer Electronic Corp Optical disc playback system - has screening plate with needle aperture to control input to detector element
US5172366A (en) * 1988-09-19 1992-12-15 Pioneer Electronic Corporation Optical information reproducing apparatus with selective photodetector output
DE3934744A1 (en) * 1989-10-18 1991-04-25 Krupp Gmbh Non-contact thickness determn. - by moving focusing lens for laser beam

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2336766A1 (en) * 1975-12-26 1977-07-22 Sony Corp RECORDING MEDIA, ITS MANUFACTURING AND APPLICATION
FR2338543A1 (en) * 1976-01-16 1977-08-12 Philips Nv AUTOMATIC OPTICAL FOCUSING SYSTEM
FR2422219A1 (en) * 1978-04-07 1979-11-02 Hitachi Ltd INFORMATION RECORDING DEVICE
EP0021510A1 (en) * 1979-06-18 1981-01-07 Koninklijke Philips Electronics N.V. Optical scanning apparatus with focussing system
WO2012075013A1 (en) * 2010-11-30 2012-06-07 Johnson & Johnson Vision Care, Inc. Laser confocal sensor metrology system
CN103229035A (en) * 2010-11-30 2013-07-31 庄臣及庄臣视力保护公司 Laser confocal sensor metrology system
US8953176B2 (en) 2010-11-30 2015-02-10 Johnson & Johnson Vision Care, Inc. Laser confocal sensor metrology system
CN103229035B (en) * 2010-11-30 2016-09-07 庄臣及庄臣视力保护公司 Laser confocal sensor metrology system
US8810784B2 (en) 2012-02-10 2014-08-19 Johnson & Johnson Vision Care Inc. Method and apparatus for determining a thickness profile of an ophthalmic lens using a single point thickness and refractive index measurements

Also Published As

Publication number Publication date
DE2453364B2 (en) 1978-06-22
NL7414695A (en) 1975-05-13
FR2251021B1 (en) 1979-06-08
DE2453364C3 (en) 1979-02-22
DE2453364A1 (en) 1975-05-28

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Legal Events

Date Code Title Description
ST Notification of lapse