JPS647331A - Focus controller - Google Patents

Focus controller

Info

Publication number
JPS647331A
JPS647331A JP16289087A JP16289087A JPS647331A JP S647331 A JPS647331 A JP S647331A JP 16289087 A JP16289087 A JP 16289087A JP 16289087 A JP16289087 A JP 16289087A JP S647331 A JPS647331 A JP S647331A
Authority
JP
Japan
Prior art keywords
lens
reflected
light
astigmatism
kinds
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
JP16289087A
Other languages
Japanese (ja)
Inventor
Takeshi Ishika
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.)
Toshiba Corp
Toshiba Intelligent Technology Co Ltd
Original Assignee
Toshiba Corp
Toshiba Intelligent Technology Co Ltd
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 Toshiba Corp, Toshiba Intelligent Technology Co Ltd filed Critical Toshiba Corp
Priority to JP16289087A priority Critical patent/JPS647331A/en
Publication of JPS647331A publication Critical patent/JPS647331A/en
Pending legal-status Critical Current

Links

Landscapes

  • Automatic Focus Adjustment (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

PURPOSE:To attain stable focus control by detecting a light beam reflected from a recording medium by means of an astigmatism means placed with a tilt to the light axis and using a detection signal so as to control the focused light to the recording medium. CONSTITUTION:A radiated laser beam L is reflected in the recording film of an optical disk 1 and the reflected divergent laser beam is converted into collimated luminous flux by an objective lens 16 at focusing. The beam L reflected in a half prism 4 and passing through a cylindrical lens 17 is made incident in an astigmatism lens 18 arranged in the optical path of the beam L. The generating line of the lens 18 crosses the optical axis of the lens 17 and tilted with respect to the optical axis. Two kinds of signals are detected from the light beam with the astigmatism given by the lens 18 from the photodetector 19 and the focus of the focused light is controlled to the disk 1 by using two kinds of the signals. Thus, stable focus control is applied.
JP16289087A 1987-06-30 1987-06-30 Focus controller Pending JPS647331A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP16289087A JPS647331A (en) 1987-06-30 1987-06-30 Focus controller

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP16289087A JPS647331A (en) 1987-06-30 1987-06-30 Focus controller

Publications (1)

Publication Number Publication Date
JPS647331A true JPS647331A (en) 1989-01-11

Family

ID=15763197

Family Applications (1)

Application Number Title Priority Date Filing Date
JP16289087A Pending JPS647331A (en) 1987-06-30 1987-06-30 Focus controller

Country Status (1)

Country Link
JP (1) JPS647331A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6947360B2 (en) * 2001-02-28 2005-09-20 Lg Electronics Inc. Method and apparatus for tilt detection in an information-recording medium

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6947360B2 (en) * 2001-02-28 2005-09-20 Lg Electronics Inc. Method and apparatus for tilt detection in an information-recording medium

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