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. 08, 2011
Filed:
Aug. 20, 2009
Tomoyuki Baba, Saitama, JP;
Chikara Yamamoto, Saitama, JP;
Kenzo Sado, Saitama, JP;
Fujinon Corporation, Saitama, JP;
Abstract
A small projection lens includes a first lens, which is a biconvex lens, an aperture, an aperture diaphragm (or an aperture), a second lens, which is a negative meniscus lens having a concave surface facing a magnification side, a third lens, which is a positive meniscus lens having a convex surface facing a reduction side, and a fourth lens, which is a biconvex lens having aspheric surfaces at both sides on an optical axis, arranged in this order from the magnification side. A minimum portion of the length of all lens elements of the small projection lens in a diametric direction vertical to the optical axis is equal to or less than 15 mm, and the small projection lens satisfies the following conditional expression: 2.5<β/S<10.0 (where S indicates the maximum length of a magnification-side image (inch) and β indicates a magnifying power).