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:
Jun. 27, 1995
Filed:
Jul. 12, 1994
Robert A Lee, Nunawading, AU;
Abstract
A diffraction grating providing an optically variable image includes a pixellated diffraction grating in which each pixel is an individual optical diffraction grating so that the pixellated diffraction grating when illuminated generates an optically variable image. In another aspect the grating in some or all of the pixels of a diffracting grating formed by a regular matrix of pixels is arranged such that a reproduction of the grating by reflection contact printing generates a zero-order pattern which is grossly flawed by Moire or Talbot fringe effects. A method of forming the diffraction grating includes producing a counterpart pixellated diffraction grating of a substantially optically invariable image wherein each pixel of the optically invariable image is maped to a respective pixel of the pixellated diffraction grating. Each grating pixel is an individual optical diffraction grating of the associated pixel in the optically invariable image, so that the pixellated diffraction grating when illuminated generates an optically variable reproduction of the optically invariable image.