JPS54123918A - Automatic focus control unit in optical reproducer of information recording medium discs - Google Patents
Automatic focus control unit in optical reproducer of information recording medium discsInfo
- Publication number
- JPS54123918A JPS54123918A JP3154578A JP3154578A JPS54123918A JP S54123918 A JPS54123918 A JP S54123918A JP 3154578 A JP3154578 A JP 3154578A JP 3154578 A JP3154578 A JP 3154578A JP S54123918 A JPS54123918 A JP S54123918A
- Authority
- JP
- Japan
- Prior art keywords
- disc
- lens
- detectors
- output
- detected
- 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
Links
- 230000003287 optical effect Effects 0.000 title 1
- 238000001514 detection method Methods 0.000 abstract 5
- 206010010071 Coma Diseases 0.000 abstract 2
- 230000003247 decreasing effect Effects 0.000 abstract 2
- 230000001965 increasing effect Effects 0.000 abstract 2
Landscapes
- Automatic Focus Adjustment (AREA)
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
Abstract
PURPOSE: To well detect the dangerous zone inrush point of a lens to a disc surface and prevent the occurrence of damages on the disc by relating and comparing one of the detection outputs differentially detecting the reproduction light signal and the other detection output.
CONSTITUTION: The reproduction light signal which is read from a disc D via read lens 6, etc. is detected with photo detectors D1, D2 and the detection outputs of the detectors D1, D2 assume increasing and decreasing as well as decreasing and increasing states according to approaching o detaching of a lens 6 to or from the disc D. The differentially detected output by of the detectors D1, D2 by a differential amplifier DA and the detection output of the detector D1 are processed in comparators COMa, COMb respectively, by which the detection outputs of the detectors D1, D2 are mutually related. When the lens 6 protrudes in the dangerous zone in proximity to the disc D, a flip-flop MISFF is set by the comparison output of the comparator COMa as a set signal and the comparison output of the comparator COMb as a clock. Thereby, the inrush of the lens into the dangerous zone is well detected and the lens 6 is forcefully detached from the disc D by way of an upper limit circuit ULC, thus the occurrence of damages on the disc by the collision is prevented.
COPYRIGHT: (C)1979,JPO&Japio
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3154578A JPS5953613B2 (en) | 1978-03-18 | 1978-03-18 | Automatic focus control device in optical reproducing device for information recording medium disk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3154578A JPS5953613B2 (en) | 1978-03-18 | 1978-03-18 | Automatic focus control device in optical reproducing device for information recording medium disk |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS54123918A true JPS54123918A (en) | 1979-09-26 |
| JPS5953613B2 JPS5953613B2 (en) | 1984-12-26 |
Family
ID=12334151
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3154578A Expired JPS5953613B2 (en) | 1978-03-18 | 1978-03-18 | Automatic focus control device in optical reproducing device for information recording medium disk |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5953613B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56111136A (en) * | 1980-02-01 | 1981-09-02 | Pioneer Video Corp | Protective device for reader of optical disc player |
| JPS5848242A (en) * | 1981-09-17 | 1983-03-22 | Pioneer Electronic Corp | Information reproducer |
| JPS6148133A (en) * | 1984-08-15 | 1986-03-08 | Hitachi Ltd | Optical disc device |
| JPS6149107A (en) * | 1984-08-15 | 1986-03-11 | Mitsubishi Heavy Ind Ltd | Condenser vacuum reduction trip interlock circuit using pressure switch of steam turbine |
-
1978
- 1978-03-18 JP JP3154578A patent/JPS5953613B2/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56111136A (en) * | 1980-02-01 | 1981-09-02 | Pioneer Video Corp | Protective device for reader of optical disc player |
| JPS5848242A (en) * | 1981-09-17 | 1983-03-22 | Pioneer Electronic Corp | Information reproducer |
| JPS6148133A (en) * | 1984-08-15 | 1986-03-08 | Hitachi Ltd | Optical disc device |
| JPS6149107A (en) * | 1984-08-15 | 1986-03-11 | Mitsubishi Heavy Ind Ltd | Condenser vacuum reduction trip interlock circuit using pressure switch of steam turbine |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5953613B2 (en) | 1984-12-26 |
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