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:
Aug. 03, 1993
Filed:
Jan. 31, 1992
Applicant:
Inventor:
Jun Hirakawa, Tokyo, JP;
Assignee:
Asahi Kogaku Kogyo K.K., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ; G02B / ;
U.S. Cl.
CPC ...
359717 ; 359793 ; 359753 ;
Abstract
A retro-focus wide-angle lens system having, in order from the object side, a negative power front group and a positive power rear group having a diaphragm stop. The front group comprises a positive first lens element and a negative meniscus second lens element having a convex surface directed towards the object. The rear group comprises a positive third lens element, a negative fourth lens element having an aspheric surface and a positive fifth lens element. The negative power of the fourth lens element increases toward the outer edge.