| 摘要 |
PURPOSE:To execute write-once and rewritable recording by irradiating a recording layer formed of a shape memory resin with a laser by varying its focal position. CONSTITUTION:The surface of a transparent substrate is provided with a recording layer essentially consisting of the shape memory resin, by which an optical disk is formed. The disk is irradiated with the energy beam from the substrate side by focusing the beam at the point near the boundary between the substrate and the recording layer. A projecting pit is formed by this irradiating and heating. This projecting pit restores the original flat state by irradiating the disk with the energy beam of the temp. slightly lower than the temp. at the time of forming the projecting pit. Then, the projecting pit has a rewritable characteristic. The recording layer is irradiated with the energy beam by focusing the beam at the point near the surface opposite to the substrate from the substrate side. A recessed pit is formed by this irradiation. Since the irradiation temp. is set at the glass transition temp. of the shape memory resin or above, the recessed pit is unerasable and stable. |
