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:
Sep. 17, 1991
Filed:
Jan. 25, 1990
Kiichirou Ueda, Hachioji, JP;
Akira Ishisaka, Hachioji, JP;
Konica Corporation, Tokyo, JP;
Abstract
A lens for a highly precise and fine projector that may response to a television of high quality must have a large aperture ratio and a wide field angle, and chromatic aberrations should be well corrected. A projector lens according to the present invention comprises, from a screen side, a first lens group including at least one positive single lens and negative single lens, a second lens group having a strong refracting power including one positive lens and negative lens, a third positive lens group having a relatively weak refracting power, and a fourth lens group having a negative lens with a concave surface having a strong curvature directed toward the screen, characterized in that the third lens group has at least one aspherical surface.