| 摘要 |
PROBLEM TO BE SOLVED: To make the thickness of an adhesive layer an optical disk formed by boding two sheets of base plates to each other by the adhesive uniform over the entire surface and to assure the beauty of the adhesive layer. SOLUTION: The disk base plate 101 is provided with an inner peripheral side projecting part 121 and an outer peripheral side projecting part 141 and the disk base plate 102 is provided with an inner peripheral side projecting part 122 and an outer peripheral side projecting part 142. The respective inner peripheral side projecting parts and outer peripheral side projecting parts are disposed to face each other via a spacing 112 and the disk base plate 101 and the disk base plate 102 are bonded to each other by the adhesive 7. The heights of the respective projecting parts described above is set at about half the thickness 111 of the adhesive layer 110. These projecting parts are capable of suppressing the diffusion of the adhesive on the same circumference on the inner peripheral side and on the same circumference on the outer peripheral side when the adhesive diffuses from the inner peripheral side and the outer peripheral side at the time of bonding of the disk base plates. |
