| 摘要 |
PURPOSE:To prevent the generation of bending or mandering of a substrate and to ensure the stable processing of information by joining the substrate and a reinforcing substrate in a body so that an inner space is formed between said reinforcing substrate and the information production layer formed on the substrate and at the same time having a non-welded state between the outer fringe parts of both substrates. CONSTITUTION:The substrates 10 and 10 are made of a plastic or glass disk having about 300mm. outer diameter, about 35mm. inner diameter and about 1-2mm. thickness respectively. An information production layer 11 made of a metallic thin film of Te, Al, etc. is formed on a single side the substrates 10 and 10 respectively. The both sides of two inner spacers 13 and 13 are welded to both substrates 10 and 10 with an adhesive. The both sides of an outer spacer 14 is welded only to the substrates 10 and 10 with an adhesive, and a recess part 14a is formed at the inner circumference surface side. The outer fringe part 12 a of a reinforcing substrate 12 is fitted into the part 14a. The change of the size is large mainly in the radius direction and small in the thickness direction of a plate. The outer circumference parts of both substrates 10 and 12 can move only in the radius direction, and therefore no warp is produced of these substrates.
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