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:
May. 03, 2005
Filed:
Sep. 11, 2003
Masaharu Eguchi, Tokyo, JP;
Masaharu Eguchi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A projection type image display apparatus capable of achieving accurate focusing of a projection optical system using an output from a photoreception sensor, is disclosed. The projection type image display apparatus includes a projection optical system and performs focusing control of the projection optical system based on an output signal from an photoreception sensor. The photoreception sensor receives light from the projection surface. The optical axis of the projection optical system is shifted with respect to a reference axis. The reference axis leads from the center of an original image formed on an image forming element to the center of the projected image. The photoreception sensor receives light from a detection area which is proximate to and includes the position of the optical axis of the projection optical system on the projection surface.