| 摘要 |
PURPOSE:To improve dimensional stability, shielding characteristic from the outdoor air and rotating balance by forming the titled carrier in such a way that two sheets of the transparent disks thereof are held by an outside circumferential ring in the state of allowing free radial expansion of the outside circumferential ends in the radial direction of said disks. CONSTITUTION:The outside circumferential ring 10 is fitted to the outside circumferential part of an assembly constituted of two sheets of the transparent disks 1, 1' having a central hole 2 engaging with a spindle and a disk-shaped core material 4 having a central hole 5 inserted therebetween. Recording layers are formed on the inside surfaces of the disks 1, 1' and a recess 6 is formed on the surface of the core material 4 facing said layers so that an air gap is provided. The disks 1, 1' and the material 4 are fixed to each other by means of an adhesive agent in the central area near the holes 2, 5. On the other hand, the outside circumferential part of the disks 1, 1' is restrained axially by the ring 10 but the outside diameter of the disks 1, 1' is made shorter than the outside diameter of the material 4 by which said part is made freely expandable in the radial direction. |
