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专利名称：Security documents
发明人：Audrey R. Burnham,Christopher J.
Ewards,Roger E. Munn
申请号：US07/152271申请日：19880204公开号：US04884828A公开日：191205
摘要：A security document has security printing formed as a moire pattern of twosuperimposed sets of generally parallel lines. In each line set the line spacing variesprogressively along the length of the lines so that each line set has one or more areas inwhich the line frequency is low and individual lines can be seen with the naked eye, andone or more further areas of high line frequency in which individual lines can only bereadily distinguished by using magnification. Futhermore, the thickness of each line variesprogressively between relatively large and relatively small values correspondingrespectively to the areas of low and high line frequency, the ration of line spacing to linethickness being approximately constant so that the color or tonal density of the securityprinting is approximately uniform. For additional security the individual line sets areprinted in inks of which the colors can be differentiated by the naked eye but not by areproducing machine used for counterfeiting. One or both of the line sets may
additionally or alternatively be printed in an ink having an anti-fraud characteristic such,for example, as water-fugitivity, solvent-sensitivity or UV fluroescence.
申请人：CMB PACKAGING (UK) LIMITED
代理机构：Diller, Ramik & Wight
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