| 摘要 |
PURPOSE:To obtain sufficient reflected light and to improve the position control of an objective lens by providing a reflecting layer which increases its reflectivity at least at >=1 kinds of waveforms in the optical memory element. CONSTITUTION:The reflecting layer 2 consisting of Al, etc., is provided on a substrate 1 consisting of glass, etc., and further, recording layers R1 to R3 are superposed. The recording layers consist of photochromic materials which are changed in coloring state by a photoreaction and are subjected to recording with light of respective waveforms lambda1 to lambda3 by varying the materials. The photochromic materials are, for example, the hetero type fulgide (Me is a methyl group) expressed by the formula and are disposed with the group of an oxazole type in the position of X in the case of the layer R1, a thiophene type in the case of the layer R2 and a pyrrole type in the case of the layer R3, respectively. The reflectivity increases at the intrinsic waveforms. The large reflected light is obtd. when the irradiation light to the optical memory coincides with lambda1 to lambda3. The position control of the objective lens by focus servo is improved. |
