OPTICAL RECORDING MEDIUM AND REPRODUCING METHOD THEREFOR

摘要

PURPOSE:To realize high density recording and reproduction of information by providing a recording layer, and a mask layer where decoloring reaction proceeds through thermal reaction upon irradiation with a reproduction light to bring about such state as the absorption at the wavelength of reproduction light is decreased. CONSTITUTION:A mask layer 10 is provided on a transparent substrate 101. The mask layer 2 contains photochromic molecules which causes photochromic reaction upon irradiation with a coloring light to lower the transmittance and to cause decoloring reaction through thermal reaction or thermally accelerated photochromic reaction upon irradiation with the reproduction light to lower the transmittance. A recording layer 3 and a protective layer 104 are formed sequentially on the mask layer 102. The photochromic material can be changed to decolored state principally through thermal reaction. In the optical recording medium, the mask layer 2 is decolored by utilizing the change to the decolored state through the thermal reaction.