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. 20, 1998
Filed:
Dec. 05, 1995
Applicant:
Inventors:
Trevor I Martin, Burlington, CA;
John F Oliver, Calgary, CA;
Assignee:
Xerox Corporation, Stamford, CT (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06K / ;
U.S. Cl.
CPC ...
235487 ; 235494 ;
Abstract
Disclosed is a method of embedding and recovering machine readable information on a substrate which comprises (a) writing data in a predetermined machine readable code format on the substrate with a photochromic marking material having a first state corresponding to a first absorption spectrum and a second state corresponding to a second absorption spectrum; and (b) thereafter effecting a photochromic change in at least some of the photochromic marking material from the first state to the second state.