JPS57142522A - Photo detector - Google Patents

Photo detector

Info

Publication number
JPS57142522A
JPS57142522A JP2788881A JP2788881A JPS57142522A JP S57142522 A JPS57142522 A JP S57142522A JP 2788881 A JP2788881 A JP 2788881A JP 2788881 A JP2788881 A JP 2788881A JP S57142522 A JPS57142522 A JP S57142522A
Authority
JP
Japan
Prior art keywords
photo detector
collecting
photo
output
lens
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
JP2788881A
Other languages
Japanese (ja)
Inventor
Toshihisa Harada
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.)
NEC Corp
Original Assignee
NEC Corp
Nippon Electric 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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP2788881A priority Critical patent/JPS57142522A/en
Publication of JPS57142522A publication Critical patent/JPS57142522A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B3/00—Focusing arrangements of general interest for cameras, projectors or printers
    • G03B3/10—Power-operated focusing

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

PURPOSE:To obtain an information signal and error signal from a single beam and to enable detecting of a displacement in focus over a wide range, by a method wherein a photo detector is placed on a line passing an optical axis, and a photo detector, collecting remaining light bundle not intercepted by aforesiad photo detector, is arranged. CONSTITUTION:A beam splitter 9 is placed above a collecting lens 10 collecting reflection light from an information recording surface 11, and a convex lens 12, converging the reflection light, in turn, is located. Two photo detectors 13 and 14 are situated on an optical axis 15 of the lens 12 such that a converging point 16 is positioned between the photo detectors 13 and 14, and the photo detector 14 is positioned so that it collects beam not intercepted by the photo detector 13. For example, if each collecting surface of the photo detectors 13 and 14 is divided into 3 parts and outputs A-F corresponding to an irraditing light amount are obtained from each division collecting surface, a focus is regulated by an output (A+B)-(C+D) of a differential amplifier 24, a tracking control is performed by an output (A+D)-(B+C) of a differential amplifier 25, and an information signal is obtained by the output (A+B+C+D+E+F) of an adder 23.
JP2788881A 1981-02-27 1981-02-27 Photo detector Pending JPS57142522A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2788881A JPS57142522A (en) 1981-02-27 1981-02-27 Photo detector

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2788881A JPS57142522A (en) 1981-02-27 1981-02-27 Photo detector

Publications (1)

Publication Number Publication Date
JPS57142522A true JPS57142522A (en) 1982-09-03

Family

ID=12233422

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2788881A Pending JPS57142522A (en) 1981-02-27 1981-02-27 Photo detector

Country Status (1)

Country Link
JP (1) JPS57142522A (en)

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