| 摘要 |
PURPOSE:To prevent the generation of cracks in dielectric layers after sticking by previously subjecting transparent substrates to an annealing treatment to specify the camber angles of two sheets of media to be stuck to each other. CONSTITUTION:The transparent substrates of the optical recording medium of a tight lamination type are previously subjected to the annealing treatment in such a manner that the camber angles of two sheets of the media to be stuck each other attain <=0.3 deg. respectively. The camber angle refers to the angle which is largest of the angles between the respective points in the transparent substrates and the horizontal direction when the transparent substrates are placed horizontal. The camber angles of two sheets of the media to be stuck to each other are, therefore, respectively decreased to <=0.3 deg. by the pretreatment of the transparent substrates. The generation of the crack is, therefore, obviated even if stresses are exerted from the outside to the dielectric layers at and under a high temp. and high humidity after the sticking. |
