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:
Feb. 14, 2012
Filed:
Jun. 01, 2009
Takanori Hisada, Yokohama, JP;
Masahiko Yatsu, Fujisawa, JP;
Koji Hirata, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a projection type image display apparatus, for enlarging an image on a image display apparatusby means of a projection lens, thereby projecting the enlarged image onto a screen, obliquely, being inclined thereto, between the projection lensand a rear-surface mirror, there are disposed free shaped surface mirrorsand, each having a free shaped surface for compensating a trapezoidal distortion due to oblique projection of the enlarged image. The surface configuration of the free shaped surface mirror is so shaped as to satisfy a following equation:|1−2|>1.4·if assuming that a distance for a light beam of an upper end of the enlarged image to reach the screen after being reflected upon a free shaped surface is 'L1', a distance for a light beam of a lower end of the enlarged image to reach the screen after being reflected upon the free shaped surface is 'L2', and a distance from an upper end of an image on the screen to a lower end thereof is “Dv”.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile