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. 02, 1986
Filed:
Nov. 13, 1984
Syuichiro Saito, Kanagawa, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
The disclosed shutter time switching device for a rotary shutter is provided with a stepping motor for controlling the opening angle of the rotary shutter. The device includes a driving mechanism for driving the stepping motor in a two-phase driving mode when switching between relatively high shutter speeds and in a single-phase driving mode when switching between relatively low shutter speeds. Optimum responsivity of the switching operation is thus obtained. The stepping motor is rotatable in a first direction and a second direction which is reverse to the first direction. To solve the problem of hysteresis of the motor, the device is provided with a further drive mechanism for driving the stepping motor in the first direction at least one step before a desired step position, regardless of whether the motor has been driven in the first or second direction for switching the shutter speed.