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:
Jan. 10, 1995
Filed:
Jul. 13, 1993
Applicant:
Inventors:
David A Luce, Clarence Center, NY (US);
Bernard Grolman, Worcester, MA (US);
Assignee:
Leica Inc., Depew, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
A61B / ; A61B / ;
U.S. Cl.
CPC ...
351232 ; 351234 ; 351237 ; 351239 ; 351243 ;
Abstract
A device for testing visual contrast sensitivity is disclosed whereby the contrast between a vectographically polarized test symbol and a reference background may be continuously varied by changing the direction of polarization of a polarization analyzer situated along the test axis. The invention is practiced by providing a chart projector or a conventional refractor with a rotatable analyzer.