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. 19, 1992
Filed:
Sep. 28, 1990
Applicant:
Inventors:
Walter Kraft, Zurich, CH;
Jurgen Nehring, Wettingen, CH;
Assignee:
Gretag Systems, Bothell, WA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
355 38 ; 355 77 ;
Abstract
A photographic color copying apparatus and an exposure control process includes measuring filters variable as a function of the spectral sensitivities of different copy materials, in particular electro-optical filters. The variable measuring filters are constructed in the manner of Solc filters or Lyot-Ohman filters and include polarizers and electro-optical crystals, preferably liquid crystals.