摘要 |
PURPOSE:To decrease the internal stress caused onto a circular base attended with the curing and shrinking of an adhesives by adhering two circular bases to a spacer while they are shifted in radial direction. CONSTITUTION:The two transparent circular bases 2, 5 made of a material such as polycarbonate are adhered and fixed via spacers 3, 4 and recording layers 1a, 1b are formed to the inner face of the bases 2,5. In adhering the bases 2, 5, an adhesives 10 of a prescribed quantity is coated to a position by a distance (l) in the radial disk direction of a spacer 4 and the adhesives 10 is applied to the spacer 3 similarly at a shifted position, and the base 2, 5 are adhered via the spacer. Thus, the deforming force attended with the curing and shrinking of the adhesives 10 is absorbed by the deformation of the spacers 3, 4 and the internal stress caused by the bases 2, 5 is suppressed to a small value. Thus, the increase in the double deffraction caused due to the adhesion distortion is suppressed. |