| 摘要 |
PURPOSE:To attain the alignment of a both side disk by the similar working to that of a one-side disc by providing a track groove and a center hole to both sides of a disk base and filling an adhesives to the full face from both sides of an intermediate base forming an information medium layer to the face of the track groove of each so as to adhere the transparent bases. CONSTITUTION:A track groove 6 for laser light guiding is provided respectively to both sides of the intermediate base and each position of the respective track groove 6 is formed incorporatedly with high accuracy. A recording medium layer 8 formed to the face of each track groove 6 is subjected to recording and reproduction by using a heat of a laser light so as to change the optical density as so-called phase change type thin film, an untraviolet ray curing type adhesive 10 is field to the full face to adhere them and the center hole 11 provided at the center of the transparent base 9 has a nearly the same diameter as that of the center hole 7 of the intermediate base 5. In overhawling the center hole as shown in alternate long and two short dashes lines 14 with respect to either track groove 6, the center hole with high accuracy to the track pit 6 of both sides if easily obtained. |
