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:
Jul. 29, 2008
Filed:
Feb. 18, 2005
Yuriko Inadachi, Yokohama, JP;
Shuji Kato, Yokohama, JP;
Hidehiro Ikeda, Yokohama, JP;
Naoyuki Ogura, Machida, JP;
Koji Hirata, Yokohama, JP;
Yuriko Inadachi, Yokohama, JP;
Shuji Kato, Yokohama, JP;
Hidehiro Ikeda, Yokohama, JP;
Naoyuki Ogura, Machida, JP;
Koji Hirata, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A projection lens apparatus includes a plurality of lenses, for enlarging and projecting, onto a screen, an original image displayed on an image generation source. The plurality of lenses are arranged, beginning with the lens nearest the screen, as first to sixth lens groups. The fourth lens group includes one meniscus lens that has a positive refracting power and has a concave lens surface directed toward the screen. The concave lens surface of the meniscus lens included in the fourth group lens has a curvature in the vicinity of an outer portion of the concave lens surface that is smaller than a curvature in a predetermined area of the concave lens surface defined between a light axis of the concave lens surface of the meniscus lens and the smaller curvature of the concave lens surface in the vicinity of the outer portion of the concave lens surface.