| 摘要 |
PURPOSE:To absorb the volumetric change by the temp. rise of the gas in an internal space by thin films and to prevent the deformation of the disk by disposing the film surface sides of two pieces of the optical disk pieces opposite to each other, holding an inner circumferential spacer and outer circumferential spacer in place between said pieces, fixing the disk pieces by an adhesive agent, providing a through-hole to at least either of the optical disk pieces and the outer circumferential spacer and sealing the through-hole with the thin films having excellent flexibility. CONSTITUTION:The double sided optical disk medium is constituted by including the optical disk pieces 1, 2, the inner circumferential spacer 3, the outer circumferential spacer 4, and the thin films 5, 6. The thin film 5 on the outer circumferential side and the thin film 6 on the inner circumferential side are for absorbing the volumetric change by the temp. change in the internal space 7. The thin films are, therefore, required to have the properties of high flexibility and high resistance to corrosion. Synthetic resins such as polyvinylidene chloride and metallic films consisting of gold, platinum, etc., are desirable as the material of said thin films. The higher reliability is obtd. if the thin films 5, 6 are fixed to the disk in the state of substituting the gas in the space 7 with an inert gas such as, for example, argon. |
