MULTILAYER REFLECTOR, AUTHENTICATION CARD, BAR CODE LABEL, AUTHENTICATION SYSTEM, AND AUTHENTICATION REGION FORMING SYSTEM
摘要
A multilayer reflector in which a latent image of authentication information is formed by partly relaxing molecule orientation in a phase difference film without needing any complex step so as to prevent the latent image to become visual because of formation of roughness of the surface. The multilayer reflector (1) has a phase difference film (10) where the phase difference ?nd<SUB>1</SUB> to the observation wavelength ? is m×?/4-?/16= ?nd<SUB>1</SUB>=m×?/4m+?/16 (m is a positive odd number) and a metal reflective plate (11) formed on the back of the phase difference film (10). An authentication region (10a) having predetermined authentication information is so formed in the phase difference film (10) that the phase difference ?nd<SUB>2</SUB> is n×?/4-?/8= ?nd<SUB>2</SUB>=n×?/4+?/8 (n is 0 or a positive even number and n<m), and a light diffusing layer (12) is formed on the front side of the phase difference film (10).
