| 摘要 |
PURPOSE: A phase varying disk used for blue laser is provided to reduce a track pitch, thus increasing information recording density and removing cross-erase. CONSTITUTION: A phase varying disk includes a transparent substrate(40), a lower dielectric film(42) formed on the substrate, and an information recording film(44) formed on the lower dielectric film. The phase varying feature of the information recording film is changed by temperature. The disk further has an upper dielectric film(46) formed on the information recording film, and a reflection film(48) formed on the upper dielectric film. The upper dielectric film has a thickness that represents optical characteristic that the ratio of light absorption rate of a crystalline portion of the information recording film to light absorption rate of an amorphous portion of the film is larger than 1. The reflection film has a thickness capable of minimizing transition of heat generated from a certain point of the information recording film to prevent the heat from changing the states of materials of other points. |
