| 摘要 |
PROBLEM TO BE SOLVED: To discriminate difference of disks by colors by providing the disks with two substrates or transparent resin layers having transmission spectra different in a visible light region or two reflection layers having different reflection spectra. SOLUTION: The first substrate 1 and the second substrate 5 have transparent spectra varying respectively in the visible light region. Previously dyed polycarbonate, etc., are used for the materials of the first substrate 1 and the second substrate 5. The previously dyed polycarbonate is prepd. by mixing dyes used from heretofore into the polycarbonate, etc., used from heretofore as the material for the substrate. The dyes used from heretofore are, for example, cyanide dyestuff, etc., in the case of blue and azo dyestuff, etc., in the case of red. As a result, a person recognizes, for example, the surface A as red and the surface B as blue when the person views the disks. |
