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:
Oct. 24, 2006
Filed:
Dec. 03, 2004
Kai Chang LU, Sutton Coldfield, GB;
Kai Chang Lu, Sutton Coldfield, GB;
3M Innovative Properties Company, St. Paul, MN (US);
Abstract
A wide-angle projection lens includes a first lens group of negative refractive power, the first lens group having at least one aspheric surface. The projection lens also includes a second lens group of substantially zero refractive power and a third lens group of positive refractive power. The projection lens satisfies the following three conditions: |F/F|<4.0 (Condition (1)), |F/F|>50 (Condition (2)) and |F/F|<3.5 (Condition (3)). In these conditions, F is the focal length of the wide-angle projection lens; Fis the focal length of the first lens group; Fis the focal length of the second lens group; and Fis the focal length of the third lens group. The wide-angle projection lens is used in a front projection display device.