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.

Date of Patent:
Jan. 14, 1992

Filed:

Apr. 20, 1990
Applicant:
Inventors:

Eric Dufresne, Paris, FR;

Pierre Chavel, Chilly Mazarin, FR;

Gabriel Sirat, Paris, FR;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03H / ;
U.S. Cl.
CPC ...
359 30 ; 359-1 ; 359495 ;
Abstract

A holographic apparatus of the type comprising a conoscopic system including a birefringent crystal inserted between two polarizers, wherein the apparatus also includes an aperture angle limiter inserted on the path of the light rays and wherein one of the birefringent crystal and the aperture angle limiter is disposed off the optical axis of the apparatus.


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