Azimuthally modulated scattering device
AssigneeRolic Technologies AG
InventorsDavid PIRES, Mohammed IBN-ELHAJ
Life of this patent
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Abstract
Optical elements with anisotropic, patterned surface relief microstructures in which information is encoded in the distribution of the orientation of different zones. From the analysis of the distribution of the light scattered from the element, the orientation distribution in the element and therefore the encoded information can be evaluated. The elements are particularly useful for securing documents and articles against counterfeiting and falsification.
Claims8
A method of using an optical element which has been manufactured by a manufacturing method comprising providing information to be encoded, defining a number of different anisotropy directions Oi to be used for encoding, defining a frequency distribution fi(θi) of zones with the different anisotropy directions, the frequency distribution fi(θi) representing the information to be encoded, determining a positional orientation distribution of zones with different anisotropy directions θi, the positional orientation distribution fitting with the determined frequency distribution, and manufacturing the optical element comprising a region with an anisotropic surface relief microstructure, which has zones with the different anisotropy directions θi, according to the determined positional orientation distribution,
- the method of using the optical element comprising:
- applying the optical element to value documents, and
- using the optical element as a security feature in the value documents.
A method for evaluating information which is encoded in an optical element which has been manufactured by a manufacturing method comprising providing information to be encoded, defining a number of different anisotropy directions Oi to be used for encoding, defining a frequency distribution fi(θi) of zones with the different anisotropy directions, the frequency distribution fi(θi) representing the information to be encoded, determining a positional orientation distribution of zones with different anisotropy directions θi, the positional orientation distribution fitting with the determined frequency distribution, and manufacturing the optical element comprising a region with an anisotropic surface relief microstructure, which has zones with the different anisotropy directions θi, according to the determined positional orientation distribution,
- the method for evaluating comprising:
- detecting of a spatial light distribution scattered from the optical element, and
- evaluating the frequency distribution fi(θi) from the detected spatial light distribution.
A method for evaluating information which is encoded in an optical element comprising a region with an anisotropic surface relief microstructure having zones with different anisotropy directions θi, wherein information is encoded in a frequency distribution fi(θi) of the zones with the different anisotropy directions, the method comprising:
- detecting of a spatial light distribution scattered from the optical element, and
- evaluating the frequency distribution fi(θi) from the detected spatial light distribution.
Dependencies are inferred from the claim text.