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:
Jul. 19, 1988
Filed:
Apr. 18, 1986
Kazuo Yamakawa, Sakai, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
A video projector lens system is provided, which comprises, from the screen side to the tube side, a first positive lens having a screen side convex surface, a second negative meniscus lens having a screen side convex surface, a third biconvex lens, and a fourth negative lens having a screen side concave surface. The first and second lenses are made of a plastic material for cancelling the temperature depending characteristic of one of the first and second lenses with the counterbalanced refractive power of the other thereof, wherein at least one aspheric surface is applied to the lens system. The third lens bearing a considerable part of the positive refractive power distributed in the whole lens system is made of a glass material for avoiding further temperature dependency.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile