| 发明名称 |
Security document using a variable dot screen |
| 摘要 |
An improved copy-proof document is disclosed having a cancellation phrase and a background pattern each printed of a plurality of elements of a geometric shape having one or more smaller uncovered areas within said geometrically shaped element.
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| 申请公布号 |
US4341404(A) |
申请公布日期 |
1982.07.27 |
| 申请号 |
US19800120624 |
申请日期 |
1980.02.11 |
| 申请人 |
BURROUGHS CORPORATION |
发明人 |
MOWRY, JR., WILLIAM H.;GEREW, KATHLEEN M. |
| 分类号 |
B41M3/14;G03G21/04;G07D7/12;(IPC1-7):B42D15/00 |
主分类号 |
B41M3/14 |
| 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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