| 摘要 |
PURPOSE:To prevent mechanical deformation of a substrate by using polyphenylene sulfide resin for the core material which acts to prevent deformation of the substrate. CONSTITUTION:The substrates 1a, 1b provided with recording films 2a, 2b thereon are jointed to the front and back surfaces of the polyphenylene sulfide resin core material 4 with adhesive 5a, 5b, 5c. Air layers 3a, 3b constituted by the substrates 1a, 1b and the core material 4 are sealed. Since the core material 4 consists of polyphenylene sulfide resin which has high mechanical strength, particularly high bending strength, the core material does not deform by its weight nor maintains residual strain as the inner strain caused by molding. Thereby, relative positions of the substrates 1a, 1b to the core material 4 show no secular change, which prevents mechanical deformation of substrates and maintains characteristics and properties of the optical disk medium. |
