| 摘要 |
PCT No. PCT/GB93/01386 Sec. 371 Date Jan. 23, 1995 Sec. 102(e) Date Jan. 23, 1995 PCT Filed Jul. 1, 1993 PCT Pub. No. WO94/02329 PCT Pub. Date Feb. 3, 1994A means of identification or document of value which includes a paper or polymer region, in particular, bank notes, passports, identification cards or any other document of sufficient value to make it liable to be copied or counterfeited, includes a watermark in the region and a liquid crystal material applied to the region and to at least a part of the watermark to produce optical effects which differ when viewed in transmitted and reflected light. |
