公开(公告)号：EP0720753B1

公开(公告)日：1998-02-04

申请号：EP94926992.2

申请日：1994-09-20

申请人： CENTRAL RESEARCH LABORATORIES LIMITED

发明人： DOBRUSSKIN, Christoph ,  SHANKS, Ian Central Research Laboratories ,  HOLDEN, John Central Research Laboratories

IPC分类号： G02F1/00 ,  G02B5/30 ,  B44F1/14 ,  B42D15/10

CPC分类号： C09D11/50 ,  C09K19/00

摘要： A coloured material comprises a plurality of substantially parallel laminae (2, 3) of a chiral liquid crystal polymer. The material appears blue when viewed normal to the surface of the laminae and red when viewed at an oblique angle. The laminae may take the form of a plurality of superimposed layers, one layer reflecting blue light and another layer reflecting infrared light when viewed normal to the surface, and the one layer reflecting ultraviolet light and the other layer reflecting red light when viewed at an oblique angle. The laminae may alternatively take the form of flakes, each flake comprising either one lamina or a plurality of layers, distributed in a light transmissive medium, e.g. to form an ink for security-marking objects or a cosmetic.