JPS5540423A - Distance information judging circuit of auto focus detector - Google Patents

Distance information judging circuit of auto focus detector

Info

Publication number
JPS5540423A
JPS5540423A JP11301878A JP11301878A JPS5540423A JP S5540423 A JPS5540423 A JP S5540423A JP 11301878 A JP11301878 A JP 11301878A JP 11301878 A JP11301878 A JP 11301878A JP S5540423 A JPS5540423 A JP S5540423A
Authority
JP
Japan
Prior art keywords
circuit
counter
count output
distance measurement
measurement end
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
Application number
JP11301878A
Other languages
Japanese (ja)
Other versions
JPS6318172B2 (en
Inventor
Shingi Hagiuda
Hiroaki Tanaka
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.)
Nikon Corp
Nippon Chemical Industrial Co Ltd
Original Assignee
Nippon Chemical Industrial Co Ltd
Nippon Kogaku KK
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 Chemical Industrial Co Ltd, Nippon Kogaku KK filed Critical Nippon Chemical Industrial Co Ltd
Priority to JP11301878A priority Critical patent/JPS5540423A/en
Priority to DE19792936992 priority patent/DE2936992A1/en
Publication of JPS5540423A publication Critical patent/JPS5540423A/en
Publication of JPS6318172B2 publication Critical patent/JPS6318172B2/ja
Granted legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G01C3/02—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G01C3/32—Measuring distances in line of sight; Optical rangefinders by focusing the object, e.g. on a ground glass screen

Abstract

PURPOSE: To eliminate the wrong recognition of the focus position by the false distance information signal by using this memory circuit and coincidence circuit.
CONSTITUTION: A latch circuit 17 is provided between the counter connected to a photometric circuit and a D/A converting circuit 18 and a memory circuit 32 is connected to the timing circuit 31 connected to a clock pulse generating circuit 13. The latch circuit 17 and memory circuit 32 are connected by way of a coincidence circuit 33. Then, when a detecting lens 11 reciprocates in each scanning period, the timing circuit 31 generates the distance measurement end pulse d of a fixed pulse width. When the memory circuit 32 which is imputted with the count output of the counter 16 receives the application of the distance measurement end pulse d, it stores the count output of that time. The storage output thereof is then compared with the count output of the counter 16 in the next scanning period in the coincidence circuit 33. When both outputs coincide with the period of the distance measurement end pulse d, reading and storing of the count output of the counter 16 in the latch circuit 17 are accomplished.
COPYRIGHT: (C)1980,JPO&Japio
JP11301878A 1978-09-14 1978-09-14 Distance information judging circuit of auto focus detector Granted JPS5540423A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP11301878A JPS5540423A (en) 1978-09-14 1978-09-14 Distance information judging circuit of auto focus detector
DE19792936992 DE2936992A1 (en) 1978-09-14 1979-09-13 Camera focussing detector distance evaluation circuit - has coincidence signal generator comparing stored and current distance signal values

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11301878A JPS5540423A (en) 1978-09-14 1978-09-14 Distance information judging circuit of auto focus detector

Publications (2)

Publication Number Publication Date
JPS5540423A true JPS5540423A (en) 1980-03-21
JPS6318172B2 JPS6318172B2 (en) 1988-04-18

Family

ID=14601368

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11301878A Granted JPS5540423A (en) 1978-09-14 1978-09-14 Distance information judging circuit of auto focus detector

Country Status (2)

Country Link
JP (1) JPS5540423A (en)
DE (1) DE2936992A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492452A (en) * 1982-04-07 1985-01-08 Tokyo Shibaura Denki Kabushiki Kaisha Picture blur-alarm device for a camera
JPS6166605A (en) * 1984-09-11 1986-04-05 Noriisa Tao Manufacture of woodflour molded product
JPS63135600A (en) * 1986-11-26 1988-06-07 松下電工株式会社 Curved surface processing of mineral fiberboard

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783269A (en) * 1972-06-05 1974-01-01 Honeywell Inc Automatic focus positioning circuit
JPS51105722A (en) * 1975-03-14 1976-09-18 Yokogawa Electric Works Ltd

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5932762B2 (en) * 1974-02-16 1984-08-10 旭光学工業 （株） focus detection device
US4010479A (en) * 1974-07-10 1977-03-01 Asahi Kogaku Kogyo Kabushiki Kaisha Focusing apparatus for optical systems

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3783269A (en) * 1972-06-05 1974-01-01 Honeywell Inc Automatic focus positioning circuit
JPS51105722A (en) * 1975-03-14 1976-09-18 Yokogawa Electric Works Ltd

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4492452A (en) * 1982-04-07 1985-01-08 Tokyo Shibaura Denki Kabushiki Kaisha Picture blur-alarm device for a camera
JPS6166605A (en) * 1984-09-11 1986-04-05 Noriisa Tao Manufacture of woodflour molded product
JPS63135600A (en) * 1986-11-26 1988-06-07 松下電工株式会社 Curved surface processing of mineral fiberboard

Also Published As

Publication number Publication date
DE2936992A1 (en) 1980-04-03
JPS6318172B2 (en) 1988-04-18
DE2936992C2 (en) 1991-02-14

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