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. 29, 1981
Filed:
Jul. 23, 1979
Yuzuru Takazawa, Shikawatashi, JP;
Shinji Nagaoka, Shikawatashi, JP;
Seiko Koki Kabushiki Kaisha, Tokyo, JP;
Abstract
In a program shutter of the type in which the aperture opening gradually increases with the lapse of time, informations such as sensitivity of the film and the object distance are introduced by an electric circuit. The system has a switching circuit for exposure control. The trigger level of the switching circuit is determined in proportion to the film sensitivity and the object distance to vary the exposure control time corresponding to the informations to automatically determine a proper aperture for flash photography. The system is capable of providing a warning indication prior to the shutter operation if the exposure control time thus obtained is longer than the time during which the aperture is fully opened.