| 摘要 |
PURPOSE:To obtain a disk having high sensitivity, a long life and high reliability by using a transparent substrate as at a least one of 2 opposite substrates and by placing the substrates opposite to each other with a fine-grained heat-insulating layer in-between. CONSTITUTION:A disk is composed of transparent polymethyl methacrylate substrates 51 having guide grooves, a recording medium 52 made of a metal, a metalloid or an org. material, a fine-grained heat-insulating layer 53 consisting of microballoons, and spacers 54. Since the heat insulating layer 53 is present between the 2 substrates 51, the mechanical strength is increased, the substrates 51 are hardly warped and waved, and they undergo little change with the passage of time. Accordingly, the disk with high sensitivity and high reliability is obtd. |
