| 摘要 |
PURPOSE:To enhance a transfer performance when stamper is used by constituting a substrate so that one of surfaces may be a plane orthogonal to a rotation center, and the cross section of the other surface may be circular cone having the oblique surface with the thick internal peripheral part and the thin external peripheral part with respect to the former surface. CONSTITUTION:A substrate 1 has a plane 1a orthogonal to a center axis c-c' and an oblique surface 1b which tilts by an angle theta with respect to the plane 1a, and it is in a rotation symmetrical shape with respect to the center axis c-c'. At the time of injection-molding, a stamper 3 forms one of the surfaces of the spacer of a mold 2, the substrate for an optical disk provided with a recording surface on the 1a side is molded, a molding material (injection material) 4 of the substrate 1 is injected from the central part of the mold 2 to the space of the mold 2, outwardly flows in a peripheral direction, fills the substrate-shaped space, and is cooled and hardened. That is, since the cross section area of the space is gradually decrease from the internal peripheral part to the external peripheral part, the injection pressure of the injection material 4 does not decrease according to the increase of a radius, and its flowability does not deteriorate. Thus, the transferring ability can be enhanced, and stress in the external peripheral part can be decreased. |
