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. 31, 2015
Filed:
Aug. 09, 2011
Zhisheng Yun, Woodbury, MN (US);
Stephen J. Willett, St. Paul, MN (US);
Zhisheng Yun, Woodbury, MN (US);
Stephen J. Willett, St. Paul, MN (US);
3M Innovative Properties Company, St. Paul, MN (US);
Abstract
Projection lens having improved properties such as a high throughput are described. In one embodiment, a projection lens is described comprising in sequential order from a screen side a first lens group, a second lens group of positive refractive power, and a third lens group of positive refractive power. At least one lens group has an aspheric surface. The ratio of the focal length of the projection lens (F) to the focal length of each of the lens groups (F, F, and F) is such that |F/F|>5, 0.5<|F/F|<0.9, and 1<F/F<8. In another embodiment, a projection lens is described comprising in sequential order from a screen side a first lens group, a second lens group of positive refractive power, and a third lens group of positive refractive power. At least one lens group has an aspheric surface. The ratio of the focal length of the projection lens (F) to the focal length of each of the lens groups (F, F, and F) is such that |F/F|>5, 0.5<|F/F|<2.0, and 1.4<F/F<8.