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. 21, 1992
Filed:
Mar. 15, 1991
Hisaharu Kaneko, Yokohama, JP;
Yuwa Ishii, Kawasaki, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A mirror rotation angle detection mechanism is provided for an optical system having a mirror which is rotatable about an axis substantially on a reflection surface thereof at which a main beam of light is reflected. The mirror has a thin reflective layer with opposite surfaces that are nearly coplanar, and one of which constitutes the main beam reflection surface. The detection mechanism includes a light emitting member to irradiate a beam of detection light onto the opposite surface of the reflective layer. A light receiving element recieves the reflected detection beam, and an angle detection circuit detects the rotation angle of the mirror in accordance with the output of the light receiving element. According to a preferred embodiment, a condenser lens may be arranged between the light emitting member and the detection beam reflection surface.