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. 26, 1991
Filed:
Apr. 06, 1989
Kou Ishizuka, Urawa, JP;
Tetsuharu Nishimura, Kawasaki, JP;
Masaaki Tsukiji, Tokyo, JP;
Satoshi Ishii, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is an optical apparatus which can be used for measuring displacement of an object. The apparatus includes an optical system for forming a linearly polarized beam whose polarization direction changes, a reflecting surface for reflecting the beam and for directing the beam in a predetermined direction, a photoelectric converter for photoelectrically converting a reflected beam directed in the predetermined direction, a polarizing device, arranged in an optical path of the reflected beam, for directing only a P-polarized beam or an S-polarized beam of the reflected beam toward the photoelectric converter.