| 摘要 |
PURPOSE:To obtain a high-reliability disk while improving adhesive strength by putting a substrate which has a recessed part formed previously at the inner circumferential end of a center hole in a surface where a recording medium layer is formed and a protection plate having a recessed part similarly opposed to each other, and charging an adhesive and sticking the both together. CONSTITUTION:An ultraviolet curing resin layer 2 and the recording medium layer 3 are provided on the top surface of the disk substrate 1, and the recessed part 8 is formed at the inner circumferential end of the center hole 6. On the other hand, a recessed part 9 is formed at the inner circumferential end of the center hole 6 of the protection plate 5 similarly, and adhesives are charged even in the recessed parts 8 and 9 when both plates 1 and 5 are stuck together through an adhesive layer 4. Thus, the adhesive strength is improved to prevent the plates 1 and 5 from separating from each other. Further, recessed parts 11 may be formed in the plates 1 and 5 even at the outer circumferential end parts of the disk and charged with an adhesive to increase the adhesive strength. Furthermore, they may be fixed by providing a surface coating layer 7 to both plates 1 and 5 including the outer circumferential end surface parts. |
