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:
May. 12, 1981
Filed:
Apr. 04, 1979
Nobuhiko Shinoda, Tokyo, JP;
Tadashi Ito, Yokohama, JP;
Fumio Ito, Yokohama, JP;
Yukio Mashimo, Tokyo, JP;
Nobuaki Sakurada, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An exposure control device is disclosed which has an extremely high accuracy as compared with the prior art, the error range being within a one-eighth step. For such a highly accurate control of exposure time, a value of exposure time to be determined is converted to a binary code of n bits, of which the lowest one bit is weighed one-eighth step. Based on the decimal number corresponding to the upper m bits of the binary code, the frequency of the control signal is adjusted and is used in reading out the lower (n-m) bits of the same binary code, whereby the period of actuation of the shutter is determined.