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:
Oct. 08, 1985
Filed:
May. 29, 1981
Applicant:
Inventor:
Jan Hoogland, Portola Valley, CA (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ;
U.S. Cl.
CPC ...
350432 ; 350573 ;
Abstract
A flat field lens system wherein the Petzval sum is corrected without requiring many spaced high powered elements or sharply bent elements. This is achieved by having the Petzval sum correction dominated by the index difference. In an embodiment suitable for use in endoscope transfer optics where medium or high aperture is required, the spherical aberration is best corrected by use of an aspheric surface on the low index material. Where high aperture is not required, as for example in a photographic wide angle objective, spherical aberration is kept low by using a relatively small aperture.