发明名称 |
SECURITY DEVICE AND METHODS AND APPARATUS FOR VERIFICATION |
摘要 |
A security device comprising a substrate (1) on or in which is provided a radiation scattering structure derived from a master member (7, Fig. 3), the radiation scattering structure causing an incident, coherent beam of radiation to scatter in a random manner whereby the scattered beams interfere to generate a speckle pattern. The structure may be an embossed pattern or two transparent layers having different refractive indices. Alternatively interference effects can be created by changes of refractive index within the volume of a transmitting material. The device is verified by comparing the speckle pattern with a reference. An auxiliary radiation scattering structure may be used to provide a composite speckle pattern. <IMAGE> |
申请公布号 |
GB8912501(D0) |
申请公布日期 |
1989.07.19 |
申请号 |
GB19890012501 |
申请日期 |
1989.05.31 |
申请人 |
DE LA RUE COMPANY PLC, THE |
发明人 |
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分类号 |
B42D15/10;G06K9/74;G06K19/14;G07D7/12;G07F7/08 |
主分类号 |
B42D15/10 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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