JPS5629847A - Optical type information recording and reproducing unit - Google Patents
Optical type information recording and reproducing unitInfo
- Publication number
- JPS5629847A JPS5629847A JP10219179A JP10219179A JPS5629847A JP S5629847 A JPS5629847 A JP S5629847A JP 10219179 A JP10219179 A JP 10219179A JP 10219179 A JP10219179 A JP 10219179A JP S5629847 A JPS5629847 A JP S5629847A
- Authority
- JP
- Japan
- Prior art keywords
- focus
- objective lens
- polarizer
- tracking control
- light source
- 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
Links
Landscapes
- Automatic Focus Adjustment (AREA)
- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Abstract
PURPOSE: To make accurate the focus tracking control, by the tracking control of focus, through the detection of the reflection light of optical beam projected to the recording medium via the objective lens located outside the light source in the focus of light source side and the polarizer provided at the light source side focus of objective lens.
CONSTITUTION: For example, the assymmetrical horizontal polarized beam 1 from the semiconductor laser light source 33 is projected on the recording medium 4 as the beam 1A through the collimator lens 34, polarized prism beam splitter 35, 1/4 wave length plate 36, polarizer 2, and objective lens 31. In this case, the polarizer 2 is provided at the external focus 32 of the objective lens 32. The reflection light 5 is the vertical polarized beam through the objective lens 31, polarizer 2, 1/4 wave length plate 36 and incident to the light detector 38 having the four-split light receiving surfaces with the reflection at the polarized prism 35. With the detected output of the photodetector 38, focus tracking control is made via the lens actuator 6. Accordingly, no transversal shift is caused, allowing the accurate focus tracking control.
COPYRIGHT: (C)1981,JPO&Japio
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10219179A JPS5629847A (en) | 1979-08-13 | 1979-08-13 | Optical type information recording and reproducing unit |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP10219179A JPS5629847A (en) | 1979-08-13 | 1979-08-13 | Optical type information recording and reproducing unit |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS5629847A true JPS5629847A (en) | 1981-03-25 |
Family
ID=14320766
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP10219179A Pending JPS5629847A (en) | 1979-08-13 | 1979-08-13 | Optical type information recording and reproducing unit |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5629847A (en) |
-
1979
- 1979-08-13 JP JP10219179A patent/JPS5629847A/en active Pending
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