| 摘要 |
PURPOSE:To prevent the deformation of an information recording medium by selecting the total stress of each layer laminated on a substrate so that the total stress can meet a specific condition. CONSTITUTION:An information recording medium is formed by successively lamination a first protective layer 2, recording layer 2, second protective layer 4, reflecting and heat radiating layer 5 on a plastic substrate 1. The total stress S of the layers 2-5 is selected so that the stress S can fall within a range which meets the condition expressed by the formula. When the stress S is selected in this way, the deformation of the medium can be prevented and tracking and focusing can be performed easily, and then, high-density recording, reproduction, and erasure can be performed repeatedly. The theta, E, b, I, and nu in the formula respectively represent, theta: the incident angle of a laser beam on the substrate at which focus servo or tracking servo in made possible, E: the Young' s modulus of the substrate, b: the thickness of the substrate, I: (outside diameter of the substrate-diameter of the hole of the substrate)X1/2 and nu: the Poison's ratio of the substrate. |
