| 摘要 |
PURPOSE:To prevent an optical disk of optical information recording medium having an air-sandwich structure from bending in any environment by providing a inner pressure controller which controls the pressure of the air layer according to changes in the external temp. and pressure. CONSTITUTION:The optical disk 1 has a recording layer 3 on the signal side of a transparent substrate. An inner circumference spacer 5 and an outer circumference spacer 6 are provided, and these spacers are made of ring-like elastic plates which have been bent to show a U-shape cross section to give elasticity in the thickness direction. Since the optical information recording medium consists of two disks 1 with using spacers 5 and 6 which give homogeneous elasticity in the thickness direction, two disks 1 parallelly move away from each other when the disk is in an environment of lower pressure or higher temp. than the weather conditions when the disk is produced. On the other hand, when the disk is in an environment of higher pressure or lower temp. than the weather conditions when the disk is produced, two disks move close to each other. Thereby, in any environment, deterioration of recording/ reproducing can be avoided. |
