| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an authenticity display material whose forgery is difficult and which is high in design property in the state of high identifiability of the reflected light from a cholesteric liquid crystal. <P>SOLUTION: A layer satisfying (1) and (3) or (2) and (3) among the following conditions (1) to (3) is used for the layer provided nearer the observation side than the liquid crystal layer 12. (1) The layer satisfies Re(λ)/λ<0.08. more preferably Re(λ)/λ<0.05 when the wavelength of light is defined as λ, and the retardation of the transmitted light within a range of an incident angle 0 to 45° at that wavelength as Re(λ). (2) ¾n<SB>z</SB>-n<SB>x</SB>¾≥¾n<SB>x</SB>-y<SB>n</SB>¾ and ¾n<SB>z</SB>-n<SB>y</SB>¾≥¾n<SB>x</SB>-n<SB>y</SB>¾ are satisfied when the refractive index in the two direction perpendicular to that sheet surface is defined as n<SB>z</SB>, and the refractive indices in the two directions orthogonal to the direction perpendicular to the sheet surface and the direction orthogonal within the sheet surface are respectively defined as n<SB>x</SB>, n<SB>y</SB>. (3) The layer other than a Lippmann hologram layer 15, among the layers laminated nearer on the observation side than the liquid crystal layer 12 is uniform in the refractive index distribution. <P>COPYRIGHT: (C)2007,JPO&INPIT |
