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:
Nov. 20, 1990
Filed:
Apr. 17, 1989
Shinichi Hasebe, Yokohama, JP;
Masayuki Sasaki, Sagamihara, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In at least one of a plurality of shutter vanes forming a shutter there are provided a plurality of openings adapted to detect the movement of the shutter vanes. A photointerrupter is turned on and off by the openings when the shutter vanes move. An output voltage of the photointerrupter is compared with a reference voltage by a comparator. A series combination of a switch, which is turned on and off by the output voltage of the comparator, and a resistor is connected between the output of the photointerrupter and ground. The output signal of the comparator is delayed. The delayed version and the output signal of the comparator are exclusive ORed to produce a train of pulses corresponding to the openings as the shutter vanes move. A drive and control section is responsive to the count of the pulses to control the operation of the shutter.