发明名称 |
OPTICALLY VARIABLE DEVICES, THEIR PRODUCTION AND USE |
摘要 |
Security documents often incorporate optically variable devices to prevent or hinder counterfeiters. Disclosed herein are layered optically variable devices such as colour-shift foils that employ a piezoelectric layer, 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 by placing an electrical potential difference across the security document. |
申请公布号 |
EP2563602(B1) |
申请公布日期 |
2015.03.18 |
申请号 |
EP20110771448 |
申请日期 |
2011.04.21 |
申请人 |
FORTRESS OPTICAL FEATURES LTD |
发明人 |
MACPHERSON, CHARLES DOUGLAS |
分类号 |
B42D25/00;B32B7/02;B42D15/00;G07D7/02 |
主分类号 |
B42D25/00 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|