Security device
US7782509B2 · kind B2 · utility
2Cited by
10References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 29, 2005 |
| Grant date | Aug 24, 2010 |
| Priority date | — |
| Expiry date | Dec 22, 2026 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB42D2035/24
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A security device comprises first zero order diffractive microstructure (1) on a substrate, a second zero order diffractive microstructure (2), and an intermediate light transmissive layer (4) separating the two diffractive microstructures. The spacing (sn,n+1) between the first (1) and second (2) diffractive microstructures is small enough so that optical interferences are produced between the diffractive microstructures. A further light transmissive layer (3) covers the second diffractive microstructure (2).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.