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:
Jul. 04, 1995
Filed:
Mar. 03, 1994
Koichi Shimada, Yokozemachi, JP;
Osamu Sato, Ranzanmachi, JP;
Canon Denshi Kabushiki Kaisha, Chichibu, JP;
Abstract
In a light amount controlling apparatus, there are provided a circular-shaped bottom plate having an opening at a center thereof, for supporting a diaphragm blade in such a manner that the diaphragm blade can be opened and closed to control an amount of light passing through the opening; base plate mounted to the bottom plate being arc-shaped so that the base plate is not projected to the opening and from a circular contour thereof; a magneto rotor rotatably supported by the base plate and having a drive lever for driving the diaphragm blade; a stator positioned and supported by the base plate, whose both poles are located opposite to each other while sandwiching the magneto rotor therewith; an electromagnetic coil surrounding the stator; and a cover member positioned and supported by the stator, and having a bearing portion for rotatably supporting the magneto rotor, and a coupling means for coupling the base plate with the cover member. The light-amount controlling apparatus further includes a Hall element for detecting magnetic force produced by the magneto rotor, and a drive control circuit for controlling an amount of a current supplied to the electromagnetic coil in order that the magnetic rotor is driven to a predetermined angular position based upon the detection result of the Hall element.