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:
May. 30, 1989
Filed:
Mar. 17, 1987
Applicant:
Inventor:
John M Palmer, Clwyd, GB;
Assignee:
Pilkington P.E. Limited, , GB;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G02B / ; G02B / ; G02B / ;
U.S. Cl.
CPC ...
350-14 ; 350453 ; 350481 ;
Abstract
An optical substantially afocal beam expander has a negative lens element spaced from a positive lens element. The lens elements are of different materials with respective coefficients of refractive index change with respect to temperature such that the effect of a temperature change on one element is at least partially compensated by the effect of the temperature change on the other element. The beam expander is therefore substantially athermalised with respect to afocality.