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. 26, 1985
Filed:
Sep. 28, 1982
Gregor Antes, Zurich, CH;
LGZ Landis & Gyr Zug AG, Zug, CH;
Abstract
In a security blank which includes a substrate which has two major surfaces, a thermoplastic layer which has a predetermined refraction index and is suitable for embossing thereon a machine-readable authenticity feature in the form of an optical microstructure, and a transparent layer which has a prearranged refraction index for covering and protecting the microstructure, and wherein the prearranged refraction index has a value different from the predetermined refraction index, and the microstructure generates a characteristic diffraction effect from light incident thereonto, the improvement includes a surface of the substrate facing the thermoplastic layer, which has within a region of the microstructure diffuse reflection characteristics of a predetermined magnitude, and wherein the thermoplastic layer is transparent, and wherein the difference between the refraction indexes is sufficiently small, and the magnitude of the diffuse reflection characteristics is sufficiently large, so that the characteristic diffraction effect of the microstructure is not normally detectable by the eye of an observer.