Patent ID: 7201821

Claim:
A discrimination method for determining the authenticity of an article by providing an optically discriminating mark having a figure portion or a character portion on the article, the discrimination method comprising steps of: fixing a film at part of the surface of a support, the film having a light reflecting layer composed of a polymer cholesteric liquid crystal having a circular polarization light selectivity for reflecting a specific circular polarization light; making the film smaller than the support; printing a printed portion at another part of the support's surface in substantially the same color as a color of the film when the film is viewed from a predetermined direction, the another part being other than the part at which the film is fixed; providing the support to the article as the discriminating mark; and viewing the discriminating mark via a first filter and a second filter, the first filter allowing only predetermined circular polarization light having a same polarization direction as circular polarization light from the light reflecting layer to pass therethrough, the second filter allowing circular polarization light having a polarized direction opposite to the predetermined circular polarization light from the light reflecting layer to pass therethrough, wherein the discriminating mark is viewed via the first filter, the color of the printed portion is not changed regardless of a change of the view angle, and the color of the film is changed by blue shift of a color of the light reflecting layer in accordance with the change of the view angle, and wherein the discriminating mark is viewed via the second filter, the color of the printed portion is not changed regardless of the change of the view angle, and the color of the film is black regardless of the change of the view angle, so that the authenticity of the article is determined.