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. 17, 2015
Filed:
Nov. 11, 2014
Canon Kabushiki Kaisha, Tokyo, JP;
Chikara Aoshima, Kawasaki, JP;
Masahiro Takayama, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
When a stepping motor is used as a driving source for a shutter device, if the stepping motor loses synchronization because of variations in load during driving or the like, it becomes unable to rotate a driving ring at that time, and this disables an exposure operation. In a first zone where a driven member is driven, but a light shielding member remains in a closed state or an open state, the motor drives the driven member in open-loop driving mode. In a second zone where the driven member is driven, and thus the light shielding member moves to the closed state or the open state, the motor drives the driven member in feed-back driving mode.