| 摘要 |
By combination of a hybrid layer formed from an orienting layer and a layer of a cross-linked liquid crystalline monomer with a reflector, and by appropriate local structuring of the molecule orientation, an optical pattern is obtained which cannot be copied using conventional photocopiers. This pattern is useful as means for protecting documents, such as banknotes, credit cards, and the like, from being copied, and can be detected by manually or automatically, operated optical reading devices.
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