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:
Nov. 03, 1981
Filed:
Jan. 07, 1980
Applicant:
Inventors:
James A Critchlow, Macedon, NY (US);
Donna U Ozern, Amherst, NH (US);
Assignee:
Xerox Corporation, Stamford, CT (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
355 71 ; 350314 ; 354296 ;
Abstract
A neutral density filter with a radially varying transmission is inserted in close proximity to the projection lens in a photocopier optical system. The filter has a transmission profile which provides compensation for photoconductor irradiance falloff due to cos.sup.4 as well as other circularly symmetrical non-uniformities in the optical system such as lens exit pupil distortion.