JPS5766534A - Automatic focusing forcible leading-in circuit - Google Patents

Automatic focusing forcible leading-in circuit

Info

Publication number
JPS5766534A
JPS5766534A JP14177580A JP14177580A JPS5766534A JP S5766534 A JPS5766534 A JP S5766534A JP 14177580 A JP14177580 A JP 14177580A JP 14177580 A JP14177580 A JP 14177580A JP S5766534 A JPS5766534 A JP S5766534A
Authority
JP
Japan
Prior art keywords
objective lens
lens
output
elevation
amplifier
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
JP14177580A
Other languages
Japanese (ja)
Other versions
JPS616449B2 (en
Inventor
Yasuo Chito
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.)
TRIO KENWOOD CORP
Trio KK
Kenwood KK
Original Assignee
TRIO KENWOOD CORP
Trio KK
Kenwood KK
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 TRIO KENWOOD CORP, Trio KK, Kenwood KK filed Critical TRIO KENWOOD CORP
Priority to JP14177580A priority Critical patent/JPS5766534A/en
Publication of JPS5766534A publication Critical patent/JPS5766534A/en
Publication of JPS616449B2 publication Critical patent/JPS616449B2/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
    • G11B7/0945—Methods for initialising servos, start-up sequences

Abstract

PURPOSE:To easily lead a lens into the control range of a focus control loop in an optical reader for a video disk, by reducing the elevation speed of an objective lens by forming a motional negative feedback loop during the elevation of the objective lens. CONSTITUTION:In an initial state, switches 27 and 30 are turned off, and a switch 33 on respectively; and a signal obtained by inverting the output pulses of a timing signal oscillator 22 is inputted to a driving amplifier 14' to elevate an objective lens 7. The electromotive force of a coil 15 as a result of the elevation of the lens 7 is passed through a bridge circuit to generate an output, which corresponds to counter electromotive force, at the output of a differential amplifier 31, and it is passed through a differentiating circuit 32 to obtain a quantity equivalent to the acceleration component of the operation of the lens 7. The output voltage of the differentiating circuit 32 is fed back to the driving amplifier 14' negatively to obtain an output waveform obtained by slanting the leading edge of the input signal to the amplifier 14'. Thus, the elevation speed of the objective lens 7 is reduced to about 1/5-1/10, so that the objective lens is led easily.
JP14177580A 1980-10-08 1980-10-08 Automatic focusing forcible leading-in circuit Granted JPS5766534A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14177580A JPS5766534A (en) 1980-10-08 1980-10-08 Automatic focusing forcible leading-in circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14177580A JPS5766534A (en) 1980-10-08 1980-10-08 Automatic focusing forcible leading-in circuit

Publications (2)

Publication Number Publication Date
JPS5766534A true JPS5766534A (en) 1982-04-22
JPS616449B2 JPS616449B2 (en) 1986-02-26

Family

ID=15299881

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14177580A Granted JPS5766534A (en) 1980-10-08 1980-10-08 Automatic focusing forcible leading-in circuit

Country Status (1)

Country Link
JP (1) JPS5766534A (en)

Also Published As

Publication number Publication date
JPS616449B2 (en) 1986-02-26

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