JPS57200951A - Extracting device for focus error signal - Google Patents

Extracting device for focus error signal

Info

Publication number
JPS57200951A
JPS57200951A JP8593381A JP8593381A JPS57200951A JP S57200951 A JPS57200951 A JP S57200951A JP 8593381 A JP8593381 A JP 8593381A JP 8593381 A JP8593381 A JP 8593381A JP S57200951 A JPS57200951 A JP S57200951A
Authority
JP
Japan
Prior art keywords
signal
focus error
error signal
unevenness
focus
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
JP8593381A
Other languages
Japanese (ja)
Other versions
JPS6259369B2 (en
Inventor
Tsuneo Hirose
Shinichi Tanaka
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial 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 Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Priority to JP8593381A priority Critical patent/JPS57200951A/en
Publication of JPS57200951A publication Critical patent/JPS57200951A/en
Publication of JPS6259369B2 publication Critical patent/JPS6259369B2/ja
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

Abstract

PURPOSE:To prevent the influence of the spherical aberration of a lens and to generate an accurate focus error signal, by deducting an error component due to the unevenness of a pit part from the focus error signal. CONSTITUTION:A beam of light reflected by a disk 11 enters a two-split photodetector 13, whose output is inputted to an unevenness signal regeneration part 14 and a differential focus error extraction part 15. The regeneration part 14 regenerates an unevenness signal by the sum of both outputs from said photodetectot 13. The extraction part 15, on the other hand, generates a focus error signal by the difference between both the outputs from the photodetector 13. A pitless part focus error signal extraction part 16 is composed of a gate circuit, etc., and extracts a focus error signal regarding only a pitless part by using the unevenness signal as a synchronizing signal. This pitless part focus signal is amplified by an amplification part 17 to drive a focus actuator 18.
JP8593381A 1981-06-03 1981-06-03 Extracting device for focus error signal Granted JPS57200951A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8593381A JPS57200951A (en) 1981-06-03 1981-06-03 Extracting device for focus error signal

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8593381A JPS57200951A (en) 1981-06-03 1981-06-03 Extracting device for focus error signal

Publications (2)

Publication Number Publication Date
JPS57200951A true JPS57200951A (en) 1982-12-09
JPS6259369B2 JPS6259369B2 (en) 1987-12-10

Family

ID=13872555

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8593381A Granted JPS57200951A (en) 1981-06-03 1981-06-03 Extracting device for focus error signal

Country Status (1)

Country Link
JP (1) JPS57200951A (en)

Also Published As

Publication number Publication date
JPS6259369B2 (en) 1987-12-10

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