| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk which facilitates increasing of density by improving the transferability and releasability of an optical disk substrate to and from a stamper. SOLUTION: The wall surface of in the track width direction of the recessed parts 2 the optical disk which is formed with recessed parts 2 constituting pits or grooves along track on an optical disk substrate 1 and is formed with a recording film 3 thereon consists of a steeper first sloping part 5a having an inclination to make the opening width of the recessed parts 2 narrower the nearer the base part side and existing on the bottom side across an inflection point 4 and a second sloping part 5b existing at the opening end side less steeper in the inclination than the first sloping part 5a. The wall surface of the track width direction of the recessed parts 2 of the optical disk constituted in such a manner inclines gently on the opening end side and as a result, the flow of the resin at the time of injection molding of the optical disk by using a stamper is smoothed and the transferability is improved. Simultaneously, the opening end is made no more acute in angle, by which the release of the optical disk from the stamper after molding of the optical disk is facilitated. The recording film material is more easily intruded into the recessed parts 2 at the time of forming of the recording film 3 and, therefore, the formation of the recording film is easy particularly when the recording film 3 is multilayered. |
