Patent Number: 7,738,173

Title: Optical safety element and system for visualising hidden information

Abstract: The invention concerns an optical security element and a system for visualising items of concealed information comprising such an optical security element. The optical security element has a substrate layer in which a relief structure defined by relief parameters, in particular relief shape, relief depth, spatial frequency and azimuth angle, is shaped in the surface region defined by an X-axis and a Y-axis, for producing an optically perceptible effect. One or more of the relief parameters defining the relief structure are varied in the surface region in accordance with a parameter variation function. The surface region is divided into one or more pattern regions and a background region. One or more of the relief parameters defining the relief structure are varied in the one or more pattern regions in accordance with a parameter variation function which is phase-displaced in relation to the parameter variation function of the background region. There is further provided a verification element which has a verification grating which is defined by a periodic transmission function and whose period corresponds to the period of the parameter variation function.

Inventors: Schilling; Andreas (Hagendorn, CH), Tompkin; Wayne Robert (Baden, CH), Staub; Rene (Hagendorn, CH)

Assignee: OVD Kinegram AG

International Classification: G02B 5/18 (20060101)

Expiration Date: 2022-06-15 0:00:00