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:
Nov. 16, 2010
Filed:
Sep. 03, 2001
Christopher Robert Lawrence, Farnborough, GB;
Peter Vukusic, Exeter, GB;
John Roy Sambles, Exeter, GB;
Christopher Robert Lawrence, Farnborough, GB;
Peter Vukusic, Exeter, GB;
John Roy Sambles, Exeter, GB;
Qinetiq Limited, , GB;
Abstract
An iridescent material comprises a diffraction grating incorporating a plurality of sheets () of a first substantially transparent material in parallel alignment and spaced away apart by quantities of a second substantially transparent material (), the second material having a refractive index significantly lower than the refractive index of the first material, the plates being tilted at an angle θ to an axis X and the grating having a period d(X) in the direction of axis X, the angle θ and period d being such that a second diffraction grating is provided along an axis Z, perpendicular to axis X, the second diffraction grating having a period d(Z) and consisting of ten periods or less and whereby, the diffraction conditions of the grating can be simultaneously fulfilled by electromagentic radiation of a range of wavelength thereby causing iridescence. Materials according to the invention have applications in inter alia document security, anti-counterfeiting measures, artwork, gift wrapping paper and cards and clothing design.