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:
Apr. 25, 2006
Filed:
Jun. 23, 2005
Shinya Sannohe, Neyagawa, JP;
Hideki Ishinaga, Ibaraki, JP;
Takamasa Yoshikawa, Suita, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An illuminating optical system for focusing a radiant light of a light source () onto a reflecting light valve () and a projection lens () for magnifying and projecting a reflected light from the reflecting light valve () onto a screen are provided, a diaphragm () is disposed at a substantially conjugate position of an entrance pupil of the projection lens () on an optical path of the illuminating optical system, the diaphragm () has an opening whose area is changed by a light-shielding member, and a shape of a shielded portion of the diaphragm () shielded by the light-shielding member is rotationally asymmetric to an optical axis () of the illuminating optical system. Accordingly, shielding of necessary light can be better avoided compared with a diaphragm for changing the light-shielding area in a rotationally symmetric manner, for example, a diaphragm for narrowing the opening concentrically, making it possible to improve contrast performance while minimizing brightness reduction.