Method of designing a light-redirecting surface of a caustic layer, an optical security element comprising the designed light-redirecting surface of the caustic layer, a marked object, use and method of authenticating the object
US12214612B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 2019 |
| Grant date | Feb 4, 2025 |
| Priority date | — |
| Expiry date | Nov 10, 2041 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0927
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
The invention relates to a method of designing a refractive transparent or partially transparent light-redirecting surface, or a reflective light-redirecting surface, of a caustic layer comprising providing a discrete representation of an input target image, calculating a generalized power diagram for a set of image pixels pi of the target image and computing a piecewise light-redirecting surface of the caustic layer based on a calculated optimal set of weights minimizing a cost function associated with the set of image pixels pi. The invention also relates to an optical security element, a marked object, a method of visually authenticating an object and use of the optical security element for authenticating or securing against counterfeiting.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.