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:
Mar. 29, 1994
Filed:
Dec. 04, 1989
Hansjurgen Merkle, Munich, DE;
Joseph Lass, Munich, DE;
Alexander Hierweger, Rottach-Egern, DE;
Wolfgang Killar, Munich, DE;
Erwin Lob, Munich, DE;
Abstract
A multilayer identity card exhibits an outer color layer of a first color and an inner color layer of a second color to allow for identity cards and the like to be written on in several colors. While the outer color layer absorbs virtually no laser beam light used for writing, the second, inner color layers absorbs the laser light. This causes the material of the second color layer to be thermally broken down during the writing operation, i.e. vaporized, sublimated, exposed to a chemical or physical reaction, so that the formation of pressure and resulting eruption blasts the first layer into particles. This makes the second color layer visible. Instead of the second color layer one can also provide a transparent layer of varnish having suitable properties in order to expose a multicolor security print, for example, below this transparent layer of varnish.