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. 03, 2009
Filed:
Dec. 07, 2007
Etsuro Kawakami, Akishima, JP;
Yasuyuki Tejima, Tokyo, JP;
Etsuro Kawakami, Akishima, JP;
Yasuyuki Tejima, Tokyo, JP;
Casio Computer Co., Ltd., Tokyo, JP;
Abstract
A high-performance lens system including lens elements of small diameters for projecting on to a screen or the like in an enlarged fashion images from light valves such as mainly DMDs (Digital Micromirror Devices) for forming images by changing reflecting directions of light is provided. A lens system includes, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, the second lens group being configured to include, sequentially in that order from a magnifying side thereof, a first sub-lens group orlens group having a negative refractive power as a whole and a second sub-lens group orlens group having a positive refractive power as a whole, and depending upon applications, a third lens group made up of a single positive lens element is provided in the vicinity of a light valve such as a DMD on a contracting side of the second lens group.