| 摘要 |
PURPOSE:To permit recording of a ternary coded signal and to improve recording density by projecting a high power laser and lower power laser in two stages onto an optical information recording medium formed with a thin alloy film composed of Au and Si on a substrate. CONSTITUTION:The Au-Si alloy is in the amorphous state and the reflectivity thereof is Ra from a room temp. to temp. T1 or below when the laser luminous flux having a prescribed temp. distribution is projected to the thin Au-Si alloy film. The phase transfer from the amorphous to crystal arises and the reflectivity Rb decreases at the temp. T1. Au precipitates and the reflectivity Rc increases to make Rb<Ra<Rc at T2 higher than the temp. T1. The Au is precipitated to increase the reflectivity Rc by projecting the high power laser to the optical information recording medium formed with the thin Au-Si alloy film on the substrate. The phase transfer to the crystal is induced to increase the reflectivity Rc by projecting the low power laser thereto. The ternary coded writing is thus permitted. |
