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:
Feb. 19, 1985
Filed:
Jul. 14, 1980
Applicant:
Inventors:
Berkeley M Ferro, Barnehurst, GB;
Aubrey D Walker, North Harrow, GB;
Assignee:
The Post Office, London, GB;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B42D / ;
U.S. Cl.
CPC ...
283 92 ; 235491 ; 283904 ; 283 75 ; 283109 ; 283 94 ; 428916 ; 428913 ; 430 10 ;
Abstract
A credential, such as a passport or an identification card, is provided, for example by impregnation or coating, with a phosphorescent composition which includes at least two phosphorescence activators which exhibit different emission characteristics both with respect to wavelength and lifetime so that, when the composition is irradiated, the initial afterglow changes color, for example from green to blue.