| 摘要 |
PURPOSE:To obtain an external appearance with rainbow color up to the vicinity of outer circumference by increasing a spiral pitch more than a prescribed pitch at the outer circumference side from an information recording area in a short time. CONSTITUTION:The spiral pitch is increased more than the prescribed pitch at the outer circumference from the information recording area. That is, a recording pit 1 is formed on the surface of the stamper. The recording pit 1 consists of a lead-in area 2, a program area 3, a lead-out area 4 sequentially from the inner circumference of the stamper and the spiral pitch is, e.g., 1.6mum. The outer side from the area is an external appearance decoration area 5 and made of the recording pit 1 similarly and the spiral pitch is 5mum. Thus, the optical disk stamper showing rainbow color external appearance up to the outermost circumference is manufactured in a few processing time independently of the length of the program. |
