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:
Jun. 24, 2003
Filed:
Mar. 19, 2001
Patricia H. DeLuca, Round Rock, TX (US);
Dennis F. Vanderwerf, Austin, TX (US);
3M Innovative Properties Company, St. Paul, MN (US);
Abstract
An overhead projector including a Fresnel lens, a single element meniscus projection lens having a concave side and a convex side, and a folding mirror placed in an optical path between the Fresnel lens and the projection lens. The projection lens is oriented to have the concave side optically facing the Fresnel lens. The optical design of the overhead projector follows the following equation, F =(F (M +1)/M −SLD)/(M +1), where the Fresnel lens has a focal length F , and a magnification M , the projection lens has a focal length F and a magnification M , and SLD is the distance from the stop position and the projection lens.