| 摘要 |
PURPOSE:To obtain a high-reliability optical information carrier disk while reducing an impulsive force applied to a sticking boundary surface by making one of two discoid susbstrates larger in external diameter until it is larger than the external diameter of an adhesive layer charged in the sticking boundary surface, and joining the two substrates together. CONSTITUTION:For example, a disk 11 is formed by providing a resin layer 3 which sets by ultraviolet-ray irradiation and has a track groove for laser light guidance and a recording mediumm layer 4 to a disk substrate 2 and sticking a protection substrate 6 through an adhesive layer 5; and the external diameter of the substrate is made a little bit larger than that of the substrate 6, and an adhesive is allowed to run round to outer circumferential surfaces 13 and 13' to join the substrates together. In another way, the outer circumferential surface 7 is made high intermediately and the highest part 15 is formed deviating from the adhesive layer and disk surfaces 9 and 9. Consequently, even if the disk 11 falls, no direct impact is applied to the sticking surface unlike a conventional end part and separation is prevented. |
