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. 03, 1992
Filed:
Jun. 07, 1991
Applicant:
Inventor:
Dennis F Vanderwerf, Austin, TX (US);
Assignee:
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G03B / ;
U.S. Cl.
CPC ...
353102 ; 353 38 ; 353D / ;
Abstract
This invention consists of a wide-angle, multi-element condenser system for an overhead projector that provides uniform illumination at the plane of the projection transparency, and a well-formed lamp image at the entrance pupil of the projection lens. This is accomplished by using a combination of a glass spherical meniscus lens, a glass plano-convex spherical lens and a plastic aspheric Fresnel lens system.