JPS5629847A - Optical type information recording and reproducing unit - Google Patents

Optical type information recording and reproducing unit

Info

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
Application number
JP10219179A
Other languages
Japanese (ja)
Inventor
Akinori Watabe
Susumu Yonezawa
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.)
Nippon Telegraph and Telephone Corp
Original Assignee
Nippon Telegraph and Telephone 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 Nippon Telegraph and Telephone Corp filed Critical Nippon Telegraph and Telephone Corp
Priority to JP10219179A priority Critical patent/JPS5629847A/en
Publication of JPS5629847A publication Critical patent/JPS5629847A/en
Pending legal-status Critical Current

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
JP10219179A 1979-08-13 1979-08-13 Optical type information recording and reproducing unit Pending JPS5629847A (en)

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)

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