JPS5514580A - Focus servo unit - Google Patents

Focus servo unit

Info

Publication number
JPS5514580A
JPS5514580A JP8799878A JP8799878A JPS5514580A JP S5514580 A JPS5514580 A JP S5514580A JP 8799878 A JP8799878 A JP 8799878A JP 8799878 A JP8799878 A JP 8799878A JP S5514580 A JPS5514580 A JP S5514580A
Authority
JP
Japan
Prior art keywords
comparator
focus servo
signal
disc
distance
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
JP8799878A
Other languages
Japanese (ja)
Other versions
JPS6313261B2 (en
Inventor
Minoru Kosake
Tetsuo Shimizu
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.)
Pioneer Video Corp
Universal Pioneer Corp
Original Assignee
Pioneer Video Corp
Universal Pioneer Corp
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 Pioneer Video Corp, Universal Pioneer Corp filed Critical Pioneer Video Corp
Priority to JP8799878A priority Critical patent/JPS5514580A/en
Publication of JPS5514580A publication Critical patent/JPS5514580A/en
Publication of JPS6313261B2 publication Critical patent/JPS6313261B2/ja
Granted legal-status Critical Current

Links

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
  • Control Of Position Or Direction (AREA)

Abstract

PURPOSE: To accurately start the focus servo unit, by comparing the signal of S-shaped characteristics representing the relation of distance between the disc and the readout unit with the reference signal and introducing the output of the comparator to the control amplifier via the switch means.
CONSTITUTION: The signal produced accompanied with the change in the shape of beam spot formed on the photo detection element split into four, for example, is fed to the terminals 1 and 2, and it is fed to the differential amplifier 3 to obtain the S-shaped characteristics representing the relation of distance between the disc and the readout unit. The signal of S-shaped characteristics is inputted to the comparator 4 having hysteresis characteristics and it is compared with the reference signal at the comparator 4, and the control amplifier 22 which controls the distance between the disc and the readout unit via the flip flop ON and OFF according to the output of the comparator 4 starts accurate starting for the focus servo unit.
COPYRIGHT: (C)1980,JPO&Japio
JP8799878A 1978-07-19 1978-07-19 Focus servo unit Granted JPS5514580A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8799878A JPS5514580A (en) 1978-07-19 1978-07-19 Focus servo unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8799878A JPS5514580A (en) 1978-07-19 1978-07-19 Focus servo unit

Publications (2)

Publication Number Publication Date
JPS5514580A true JPS5514580A (en) 1980-02-01
JPS6313261B2 JPS6313261B2 (en) 1988-03-24

Family

ID=13930453

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8799878A Granted JPS5514580A (en) 1978-07-19 1978-07-19 Focus servo unit

Country Status (1)

Country Link
JP (1) JPS5514580A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58121144A (en) * 1981-12-31 1983-07-19 コントロール　データ　コーポレーシヨン Convergence initialization controller
JPS62144008A (en) * 1985-12-18 1987-06-27 Hitachi Ltd Apparatus for inspecting pattern of printed circuit board

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5830263A (en) * 1981-08-17 1983-02-22 Aihon Kk Transmission line carrying type simultaneously talking interphone

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5830263A (en) * 1981-08-17 1983-02-22 Aihon Kk Transmission line carrying type simultaneously talking interphone

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58121144A (en) * 1981-12-31 1983-07-19 コントロール　データ　コーポレーシヨン Convergence initialization controller
JPH0339334B2 (en) * 1981-12-31 1991-06-13 Control Data Corp
JPS62144008A (en) * 1985-12-18 1987-06-27 Hitachi Ltd Apparatus for inspecting pattern of printed circuit board

Also Published As

Publication number Publication date
JPS6313261B2 (en) 1988-03-24

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