| 摘要 |
PURPOSE:To obtain a disk having high sensitivity, a long life and high reliability, by using a transparent substrate as at least one of 2 opposite substrates and by placing the substrates opposite to each other with a porous heat insulating layer made of an org. material in-between. CONSTITUTION:A disk is composed of transparent polymethyl methacrylate substrates 51, a recording medium 52 made of a metal, a metalloid or an org. material, a porous heat insulating layer 53 made of urethane resin, epoxy resin or other org. material, and spacers 54. Since the heat insulating layer 53 is present between the 2 substrates 51, 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. |
