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:
Jun. 23, 2009
Filed:
Aug. 08, 2005
Tetsu Ohishi, Hiratsuka, JP;
Hiroki Yoshikawa, Hiratsuka, JP;
Takanori Hisada, Yokohama, JP;
Koji Hirata, Yokohama, JP;
Masahiko Yatsu, Fujisawa, JP;
Daisuke Imafuku, Fujisawa, JP;
Tetsu Ohishi, Hiratsuka, JP;
Hiroki Yoshikawa, Hiratsuka, JP;
Takanori Hisada, Yokohama, JP;
Koji Hirata, Yokohama, JP;
Masahiko Yatsu, Fujisawa, JP;
Daisuke Imafuku, Fujisawa, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
To eliminate or otherwise reduce non-uniform brightness of an image of a display apparatus, an image is projected through a projection optical system having a projection lens (), curved surface reflection mirrors (and), and a reflection mirror () onto a rear surface of the rear-surface projection type screen (). The rear-surface projection type screen includes a Fresnel lens sheet (), wherein the prism surfaces of the Fresnel lens are formed in an aspheric configuration, thereby letting the light beams from the screen to exit at an exit angle of about zero (0) degree relative to a line perpendicular to the screen surface, over most of the entire surface thereof. It is possible to obtain a projection image that having uniform brightness in an image display apparatus while maintaining a thin cabinet () profile.