| 摘要 |
PURPOSE:To prevent the microcracks which are generated on the inside circumference of the central hole of a glass substrate by coating the inside circumferential end face of said hole with an org. resin and cutting the org. resin-coated part to match the concentricity of the guide groove and central hole of an optical disk. CONSTITUTION:Org. resin coating materials of a thermoplastic resin, thermosetting resin, etc., are used as the org. resin material in contact with the inside circumferential end face of the glass substrate 1. The org. resin film 2 coats the part where a taper cone central shaft and the central hole 11 of the disk come into contact with each other. The org. resin coating coated on the inside circumferential end face is cut in order to match the concentricity if the concentricity of the guide groove and the central hole is not matched after the org. resin coating. While the preferred thickness of the film 2 is usually about 20-50mum, the film thicker than said value needs be formed in order to assure the allowance for cutting. |
