JPS5538661A - Detector for abnormal position of focus lens of optical information reader - Google Patents
Detector for abnormal position of focus lens of optical information readerInfo
- Publication number
- JPS5538661A JPS5538661A JP11108578A JP11108578A JPS5538661A JP S5538661 A JPS5538661 A JP S5538661A JP 11108578 A JP11108578 A JP 11108578A JP 11108578 A JP11108578 A JP 11108578A JP S5538661 A JPS5538661 A JP S5538661A
- Authority
- JP
- Japan
- Prior art keywords
- disc
- lens
- light
- focus lens
- 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
Landscapes
- Automatic Focus Adjustment (AREA)
- Moving Of The Head For Recording And Reproducing By Optical Means (AREA)
Abstract
PURPOSE: To prevent a focus lens and video disc for coming in contact by making a photo detecting element detect light flux of large diameter when focusing is defective.
CONSTITUTION: Laser light flux from laser source 1 is focused on video disc 8 by focus lens 7 through 1/4-wavelength board 4, tangential mirror 5 and tracking mirror 6. The reflected light of it from disc 8 returns through the same light passage. When lens 7 approaches disc 8 and defective focusing is caused, the reflected light from disc 8 in creases in diameter and is detected by photo detecting element 14 which is provided in the middle between wavelength board 4 and mirror 5 and fixed-distance away from the light axis. The quantity of this detected light increases as lens 7 approaches disc 8 from a fixed position, and lens and disc 8 are prevented from meeting each other by performing focus servocontrol of lens 7 by the detection output of element 14. Similary, the existence of the disc can be detected.
COPYRIGHT: (C)1980,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11108578A JPS6038770B2 (en) | 1978-09-09 | 1978-09-09 | Focus lens abnormal position detection device for optical information reading device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP11108578A JPS6038770B2 (en) | 1978-09-09 | 1978-09-09 | Focus lens abnormal position detection device for optical information reading device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS5538661A true JPS5538661A (en) | 1980-03-18 |
JPS6038770B2 JPS6038770B2 (en) | 1985-09-03 |
Family
ID=14551992
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP11108578A Expired JPS6038770B2 (en) | 1978-09-09 | 1978-09-09 | Focus lens abnormal position detection device for optical information reading device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6038770B2 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5870434A (en) * | 1981-10-22 | 1983-04-26 | Toshiba Corp | Optical head |
US4723234A (en) * | 1982-06-04 | 1988-02-02 | Sony Corporation | Optical disc player |
-
1978
- 1978-09-09 JP JP11108578A patent/JPS6038770B2/en not_active Expired
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5870434A (en) * | 1981-10-22 | 1983-04-26 | Toshiba Corp | Optical head |
US4723234A (en) * | 1982-06-04 | 1988-02-02 | Sony Corporation | Optical disc player |
Also Published As
Publication number | Publication date |
---|---|
JPS6038770B2 (en) | 1985-09-03 |
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