Document having an optical-diffraction authenticating element
AssigneeLGZ Landis & Gyr Zug AG
InventorGregor Antes
Life of this patent
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Abstract
A document includes a substrate which has an outer surface and defines a plane, and a coordinate system which is defined with respect to the plane. A diffraction-optical authenticating element covers at least part of the outer surface, and generates at least one color pattern constituting a visually testable feature which verifies the authenticity of the document. The diffraction-optical authenticating element provides a color pattern moving at a predetermined velocity along a predetermined track when the document is illuminated from a first direction and viewed from a second direction, as defined with respect to the coordinate system, upon the document being rotated within the plane along a prearranged sense of rotation, and at a prearranged velocity.
Claims7
A document comprising:
- a substrate having an outer surface defining a plane, a diffraction-optical authenticating element covering at least a part of said outer surface and capable of generating at least one color pattern constituting a visually testable feature verifying the authenticity of said document,
- said diffraction optical authenticating element including a diffraction grating structure which defines a predetermined movement track, said grating structure having a spatial frequency and an angular orientation, at least one of which varies along said track, such that, when said document is illuminated from a first direction and viewed from a second direction and is rotated within said plane, adjacent regions of said diffraction grating structure successively diffract light along said second direction to provide said color pattern which appears to move along said movement track.
An authenticating element for use in connection with a document comprising:
- a diffraction optical authenticating element covering at least part of a surface of said document and capable of generating at least one color pattern constituting a visually testable feature verifying the authenticity of said document, said diffraction optical authenticating element including a diffraction grating structure which defines a predetermined movement track, said grating structure having a spatial frequency and angular orientation at least one of which varies along said track, such that, when said document is illuminated from a first direction and viewed from a second direction and is rotated within said plane, adjacent regions of said diffraction grating structure successively diffract light along said second direction to provide said color pattern which appears to move along said movement track.
Dependencies are inferred from the claim text.