发明名称 |
DIFFRACTION GRATING AND METHOD OF MANUFACTURE |
摘要 |
A diffraction grating providing an optically variable image includes a pixellated diffraction grating in which each pixel is an individual optical diffraction grating so that the pixellated diffraction grating when illuminated generates an optically variable image. In another aspect the grating in some or all of the pixels of a diffracting grating formed by a regular matrix of pixels is arranged such that a reproduction of the grating by reflection contact printing generates a zero-order pattern which is grossly flawed by Moire or Talbot fringe effects. A method of forming the diffraction grating includes producing a counterpart pixellated diffraction grating of a substantially optically invariable image wherein each pixel of the optically invariable image is maped to a respective pixel of the pixellated diffraction grating. Each grating pixel is an individual optical diffraction grating of the associated pixel in the optically invariable image, so that the pixellated diffraction grating when illuminated generates an optically variable reproduction of the optically invariable image. |
申请公布号 |
EP0490923(A4) |
申请公布日期 |
1992.11.19 |
申请号 |
EP19900912877 |
申请日期 |
1990.09.04 |
申请人 |
COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANIZATION |
发明人 |
LEE, ROBERT ARTHUR |
分类号 |
B42D15/00;B42D25/00;B42D25/29;G02B5/18;G02B27/44;G03H1/30;G06K19/16 |
主分类号 |
B42D15/00 |
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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