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:
May. 22, 2012
Filed:
May. 21, 2010
Yuuichiro Iijima, Hitachinaka, JP;
Masayuki Hachiya, Hitachinaka, JP;
Rieko Hachiya, Legal Representative, Tokyo, JP;
Koichi Asami, Honjyo, JP;
Yusuke Miyazaki, Hitachinaka, JP;
Kazuhiro Zama, Nagoya, JP;
Yuuichiro Iijima, Hitachinaka, JP;
Masayuki Hachiya, Hitachinaka, JP;
Rieko Hachiya, legal representative, Tokyo, JP;
Koichi Asami, Honjyo, JP;
Yusuke Miyazaki, Hitachinaka, JP;
Kazuhiro Zama, Nagoya, JP;
Hitachi High-Technologies Corporation, Tokyo, JP;
Abstract
A laser beam oscillated from a laser source is folded in its path by first and second plane mirrors and enters a beam expander. The surface of each plane mirror is deteriorated with illumination by the laser beam and the reflectance is reduced. To avoid a light quantity of the laser beam entering the beam expander from being reduced below a reference value, when the laser beam is illuminated over a certain time, a position on each of the first and second plane mirrors at which the laser beam is illuminated is changed by a structure for rotating and/or translating a reflecting surface of each plane mirror on a plane, which includes the plane mirror, while an optical axis is kept same. Thus, the useful life of each plane mirror can be prolonged without displacing the optical axis.