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:
Mar. 02, 2010
Filed:
Jun. 23, 2006
Takanori Hisada, Yokohama, JP;
Hiroki Yoshikawa, Hiratsuka, JP;
Tetsu Ohishi, Hiratsuka, JP;
Koji Hirata, Yokohama, JP;
Naoyuki Ogura, Machida, JP;
Takanori Hisada, Yokohama, JP;
Hiroki Yoshikawa, Hiratsuka, JP;
Tetsu Ohishi, Hiratsuka, JP;
Koji Hirata, Yokohama, JP;
Naoyuki Ogura, Machida, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A projection display is capable of suppressing both the trapezoidal distortion of an enlarged image projected on a screen by oblique projection and aberrations resulting from oblique projection and includes a projection optical system provided with lenses that can be easily manufactured and assembled. The projection optical system for obliquely projecting an image formed by a display device on the screen includes a free curved lens having a rotationally asymmetric free curved surface. The free curved lens has fringing parts having outlines of a shape coinciding with an arc of a circle having the center on the optical axis of the free curved lens.