| 摘要 |
PURPOSE:To prevent separation even in a high-temperature, high-humidity atmosphere, to minimize the deterioration of a recording film, and improve the reliability by irradiating the entire groove formation surface of a disk base material in which a groove for light guidance is formed with far ultraviolet rays and providing cleaning effect. CONSTITUTION:The groove 2 for light guidance is formed in the disk base 1 made of polycarbonate resin, and the entire groove formation surface is irradiated with far ultraviolet rays 6. The ultraviolet-ray excited physically and chemically active layer 7 which is irradiated as mentioned above has effect for removing thin-film type stains and even an uneven surface layer deterioration layer, thereby obtaining an optically uniform base material surface. A recording film 3 is formed on the active layer 7 by vapor deposition or sputtering in a short time while the active layer 7 is held clean, and the entire external surface of the disk substrate 8 is covered with a protective film 4 made of ultraviolet- ray setting resin. Consequently, the surface of the base material is irradiated with far ultraviolet rays to increase greatly the adhesive strength of the recording film to the base material. |
