| 摘要 |
PURPOSE:To produce a multilevel recording medium with a simple means and to preserve information for a long time by laminating two or more recording layers, where the absorption wavelength is changed by light irradiation, on a substrate and making respective recording layers different in maximum absorption wavelength. CONSTITUTION:Two or more recording layers 2 where the absorption wavelength is changed by light irradiation are laminated on a substrate 1, and respective recording layers 3 and 4 are different in maximum absorption wavelength from each other. Recording layers typically include dyestuffs whose absorption wavelength is changed by light irradiation, but materials whose absorption wavelength is changed by light irradiation other than dyestuffs can be used as materials of recording layers. Thus, the production method is simple and inexpensive, and information is preserved for a long time. |
