Optical readable storage disc.

摘要

An optically readable storage disc comprises a transparent substrate 1 on which a recording layer 2 is deposited which can be modified locally by means of a radiation beam, the recording layer is covered by a cover disc 3 which is secured to the substrate in a gas-tight manner at some distance from the part of the recording layer which is intended for recording, so that a sealed space 4 is enclosed between the substrate 1 and the cover disc 3. The cover disc 3 will be deformed to the greatest extent under the influence of differences between the gas pressure in the sealed space 4 and the barometric pressure because its resistance to deformation is made substantially smaller that that of the substrate so that deformation of the substrate 1 is substantially precluded.