| 摘要 |
PURPOSE:To facilitate centering respective track grooves of a both-sided disk by providing unevenness which are engaged coaxially with the track grooves each other. CONSTITUTION:Two disk substrate 1 has a constitution that a protruded part 9 and a concaved part 10 are engaged each other and are stuck together through bonding layers 5. In such a constitution, respective track grooves 2, the protruded part 9, and the concaved part 10 are formed simultaneously when the disk substrate is formed by injection forming, etc., and therefore, high coaxial accuracy can be obtained, and they can be made stably. By engaging the protruded part 9 and the concaved part 10 and by sticking them together, the positioning of respective track grooves 2 is executed easily. Protruded bonded layers 8 are removed by overhauling a center hole by making one track groove as a reference, and the finish work can be executed easily. |
