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Expired Canadian patentCanada

Camera flash photographing control device

CA 1204813 A · Owner: Asahi Kogaku Kogyo Kabushiki Kaisha · Inventors: Kuroki, Yoshifumi

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A camera flash photographing control device having a signal conversion element which generates step wave voltage for which a signal level is gradually varied as time passes by, the operation of a counter which receives a pulse signal. A signal conversion element is operated as an A-D converter in which digital signal output which corresponds to a required signal level is obtained by converting both analogue signals of luminance information of an object and iris information of a photographing lens into said required signal level at the time of light measurement before shutter release. A signal conversion element is operated as a digital-analogue converter in which analogue signal output …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted May 20, 1986. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 20, 2003.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 8, 1983
GrantedMay 20, 1986
Term endedMay 20, 2003
Patent numberCA 1204813 A
Classification (IPC)G03B7/09 +1 more

Timeline

Timeline From CIPO dates

1984198619881990199219941996199820002002Application filedFeb 8, 1983Patent grantedMay 20, 1986Term endedMay 20, 2003

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.