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:
Nov. 29, 2005
Filed:
Jan. 20, 2004
Eiki Matsuo, Suwa, JP;
Eiki Matsuo, Suwa, JP;
Seiko Epson Corporation, , JP;
Abstract
A bright, small, and inexpensive imaging lens system is provided with a short total length that can provide more than a 30 degree viewing angle and whose aberrations are excellently corrected. The imaging lens includes, in order from an object side, a positive first lens with a convex surface facing the object side, an aperture stop provided on the object side or an image side of the first lens, a meniscus second lens with a concave surface facing the object side, and a meniscus third lens with a convex surface facing the object side. Furthermore, at least one of the first lens and the second lens includes an aspheric surface, and the third lens is a biaspheric lens. In addition, the second lens and the third lens have paraxial focal lengths whose signs are different. When v max and v min are the maximum Abbe number and the minimum Abbe number among the lenses, respectively, the condition, 1.25<v max/v min, is satisfied.