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. 18, 1979
Filed:
Sep. 06, 1977
Asahi Kogaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An automatic exposure camera of the stop value control type is provided with lens stop braking to improve the accuracy of the lens stopping operation while at the same time maintaining a high operating speed. A brake magnet mechanism is provided for decelerating the lens stopping mechanism in response to a control circuit. In one form, the control circuit operates the brake magnet mechanism to effect deceleration slightly before the quantity of light reaches a suitable exposure value. Thereafter, when a stop value providing a suitable exposure value is obtained, stopping the lens stopping operation can be done with very high accuracy. In another form, the control circuit compares the variation in light due to the change in aperture with a variation rate to control the energization and de-energization of the brake magnet. In this way, the non-linear operation which is particularly evident at minimal aperture values is eliminated.