JPS5994252A - Semiconductor laser driving device - Google Patents

Semiconductor laser driving device

Info

Publication number
JPS5994252A
JPS5994252A JP57202168A JP20216882A JPS5994252A JP S5994252 A JPS5994252 A JP S5994252A JP 57202168 A JP57202168 A JP 57202168A JP 20216882 A JP20216882 A JP 20216882A JP S5994252 A JPS5994252 A JP S5994252A
Authority
JP
Japan
Prior art keywords
signal
laser
semiconductor laser
automatic focus
mode
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.)
Pending
Application number
JP57202168A
Other languages
Japanese (ja)
Other versions
JPS6331860B2 (en
Inventor
Masaharu Tsukada
Original Assignee
Canon Inc
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 Canon Inc filed Critical Canon Inc
Priority to JP57202168A priority Critical patent/JPS6331860B2/ja
Publication of JPS5994252A publication Critical patent/JPS5994252A/en
Publication of JPS6331860B2 publication Critical patent/JPS6331860B2/ja
Expired legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording 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
    • G11B7/12Heads, e.g. forming of the optical beam spot or modulation of the optical beam
    • G11B7/125Optical beam sources therefor, e.g. laser control circuitry specially adapted for optical storage devices; Modulators, e.g. means for controlling the size or intensity of optical spots or optical traces
    • G11B7/126Circuits, methods or arrangements for laser control or stabilisation

Abstract

PURPOSE:To switch the laser power of a semiconductor laser in two steps with a constant current source by providing a current switching means which modulates the laser driving current on the basis of a fixed level when the information is written. CONSTITUTION:The current flowing to a semiconductor laser 19 is set at levels decided by resistances 12, 13, 15 and 16 respectively to set an automatic focus mode. In a writing mode, a mode switching signal Sc is released, and at the same time a video signal Sv is supplied to a tri-state buffer 11. When the signal Sv is set at a high level, the potential at a point A in the diagram is reduced as compared with that set at an automatic focus mode. In this case, the information is written. When the signal Sv is set at a low level, the potential at the point A is increased as compared with the automatic focus mode. Therefore, the value of the current flowing between the collector and the emitter of a transistor 17 is increased, and the value of the current flowing to the laser 19 is decreased.
JP57202168A 1982-11-19 1982-11-19 Expired JPS6331860B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP57202168A JPS6331860B2 (en) 1982-11-19 1982-11-19

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP57202168A JPS6331860B2 (en) 1982-11-19 1982-11-19

Publications (2)

Publication Number Publication Date
JPS5994252A true JPS5994252A (en) 1984-05-30
JPS6331860B2 JPS6331860B2 (en) 1988-06-27

Family

ID=16453084

Family Applications (1)

Application Number Title Priority Date Filing Date
JP57202168A Expired JPS6331860B2 (en) 1982-11-19 1982-11-19

Country Status (1)

Country Link
JP (1) JPS6331860B2 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0223576A2 (en) * 1985-11-14 1987-05-27 Fujitsu Limited Light control circuit of an optical disc system
EP1467355A2 (en) * 2003-04-10 2004-10-13 Pioneer Corporation Information recording apparatus, information recording methods and information recording medium.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5733441A (en) * 1980-08-07 1982-02-23 Matsushita Electric Ind Co Ltd Optical information recorder and reproducer
JPS6343819A (en) * 1986-08-09 1988-02-24 Toyoda Gosei Co Ltd Door glass run for automobile

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5733441A (en) * 1980-08-07 1982-02-23 Matsushita Electric Ind Co Ltd Optical information recorder and reproducer
JPS6343819A (en) * 1986-08-09 1988-02-24 Toyoda Gosei Co Ltd Door glass run for automobile

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0223576A2 (en) * 1985-11-14 1987-05-27 Fujitsu Limited Light control circuit of an optical disc system
EP1467355A2 (en) * 2003-04-10 2004-10-13 Pioneer Corporation Information recording apparatus, information recording methods and information recording medium.
EP1467355A3 (en) * 2003-04-10 2006-06-07 Pioneer Corporation Information recording apparatus, information recording methods and information recording medium.

Also Published As

Publication number Publication date
JPS6331860B2 (en) 1988-06-27

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