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:
Dec. 20, 1988
Filed:
May. 20, 1987
Takayuki Yoshioka, Tokyo, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A projection lens system is disclosed which comprises, in order from a screen side, a first lens element having a positive focal length, a second lens element having a negative focal length, a third lens element having a positive focal length, a fourth lens element having a positive focal length and a fifth lens element having a negative focal length and a concave surface directed toward the screen side. The first and second lens element are made of plastic. Lens surfaces of the first and second lens elements are aspherical. Lens surfaces of the third and fourth lens elements are aspherical. The fifth lens element may be made of plastic. Lens surfaces of the fifth lens unit are aspherical. The system meets the following conditions: