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. 29, 2008
Filed:
Sep. 28, 2004
Hidehiro Ikeda, Yokohama, JP;
Koji Hirata, Yokohama, JP;
Shuji Kato, Yokohama, JP;
Masahiro Yamamoto, Yokohama, JP;
Masahiko Yatsu, Tokyo, JP;
Hidehiro Ikeda, Yokohama, JP;
Koji Hirata, Yokohama, JP;
Shuji Kato, Yokohama, JP;
Masahiro Yamamoto, Yokohama, JP;
Masahiko Yatsu, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A compact rear projection image display apparatus in which the projection distance in a projection optical system is substantially reduced and no reflection mirror is used, thereby eliminating a major cause of image trapezoidal distortion. The rear projection image display apparatus has a projection lens system which includes a first lens group with positive refractive power and a second lens group which further enlarges an image enlarged by the first lens group. The projection lens system enlarges and projects an image displayed on an image display device, on a transmission screen. No reflection mirror is provided between the second lens group and the transmission screen and the image enlarged by the second lens group is directly projected on the transmission screen.