| 摘要 |
PURPOSE:To prevent deformation, warpage and bend in an optical disk by forming an outer or inner peripheral spacer with a raw material having a thermal expansion coefficient larger or smaller than that of an optical disk substrate, and adhering two disk substrates on the spacer at a low temperature within a range where the optical disk substrate can be used. CONSTITUTION:The outer peripheral spacer 2 is formed with the raw material having the thermal expansion coefficient larger than that of the optical disk substrate 4, and the inner peripheral spacer 1 with the raw material having the thermal expansion coefficient smaller than that of the optical disk substrate 4, and the spacers 1 and 2 are adhered on the optical disk substrate 4 under the atmosphere of low temperature. Therefore, after the temperature of the optical disk is recovered to a room temperature, the outer peripheral spacer 2 is expanded larger than the optical disk substrate 4, and also, the optical disk substrate 4 is expanded larger than the inner peripheral spacer, thereby, tensile stress in the normal direction of the optical disk substrate 4 functions on the substrate by the two spacers 1 and 2. In such a manner, the deformation, the wrapage, and the bend in the optical disk can be prevented from occurring. |
