The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 01, 1981
Filed:
Dec. 24, 1980
Mashio Kitaura, Tondabayashi, JP;
Koji Yamamoto, Sakai, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
An exposure time control device for a camera which measures the light reflected from a surface of a leading shutter curtain and/or a surface of a film can determine exact exposure time even if difference exists between reflection factors of the surfaces, by means of a simple construction including no special light measuring circuit other than a light measuring circuit originally provided for the exposure time control purpose. A first memory or storage capacitor memorizes logarithmically compressed output of the light measuring circuit fed through a first switch when the first switch is opened in conjunction with start of the leading shutter curtain travel while a second storage or memory capacitor memorizes the output fed through a second switch when the second switch is opened in conjunction with completion of the leading shutter curtain travel. An operational circuit combines the output of the light measuring circuit at a time of full shutter opening with the output in the second memory capacitor subtracted by the output in the first memory capacitor, producing a corrected output. A time count circuit controls timing of trailing shutter curtain release in accordance with the corrected signal.