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:
Aug. 10, 2004
Filed:
Oct. 05, 2001
Applicant:
Inventors:
Kenichi Hayashi, Nagano, JP;
Tadashi Takeda, Nagano, JP;
Assignee:
Kabushiki Kaisha Sankyo Seiki Seisakusho, Nagano, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 5/18 ;
U.S. Cl.
CPC ...
G02B 5/18 ;
Abstract
In a diffraction element, a diffraction grating is formed with a grating pitch having different diffraction angles in accordance with a wavelength of a laser light beam incident thereon. The wavelength is variable in accordance with an environment temperature. The diffraction element is made of a material having a linear expansion coefficient which causes thermal variation in the grating pitch enough to compensate at least a part of the diffraction angle variation due to environment temperature change.