Optically variable devices, their production and use
US9738105B2 · kind B2 · utility
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2References
26Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 21, 2011 |
| Grant date | Aug 22, 2017 |
| Priority date | — |
| Expiry date | Sep 13, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/287
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
Security documents often incorporate optically variable devices to prevent or hinder counterfeiters. Disclosed herein are layered optically variable devices such as color-shift foils, and methods for their production and use. Such devices afford new techniques for a user of a security document to check quickly and easily whether the security document is a legitimate document or a counterfeit copy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.