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. 28, 2004
Filed:
Aug. 28, 2002
Katsunori Kawano, Ashigarakami-gun, JP;
Tatsuya Maruyama, Ashigarakami-gun, JP;
Jiro Minabe, Ashigarakami-gun, JP;
Shin Yasuda, Ashigarakami-gun, JP;
Fuji Xerox Co., Ltd., Tokyo, JP;
Abstract
Laser light emitted from a laser light source is irradiated onto a transmission-type scale, and is diffracted by a polarization hologram recorded on the transmission-type scale. Only polarization directions of ±1-order diffracted lights, among diffracted lights, are rotated by 90°. The ±1-order diffracted lights interfere with one another such that interference fringes are formed on a light-receiving surface of a photo-detector. Interference light of the ±1-order diffracted lights is transmitted through a polarizing plate. A portion of transmitted light is passed through respective slits of a slit plate and is irradiated onto the photo-detector, and intensity of irradiated light is detected. On the other hand, 0-order diffracted light, ±2-order diffracted lights, and the like, whose polarization directions are not rotated, cannot pass through the polarizing plate, and are blocked before being detected at the photo-detector.