| 摘要 |
PURPOSE:To eliminate an error in information recording and reproduction even in long-period storage by forming an optical disk which have a hollow part between plural circular substrates arranged across spacers with recording layers inside and roughening the surface of the optical disk at the side of the spacer hollow part. CONSTITUTION:An internal end part spacer 40 having the roughened surface at the side of the hollow part 3 is used. The spacer 40 uses a material which has larger diffusivity than the substrates 1, and then when an optical disk is cooled speedily, dew is condensed on the spacer 40 to prevent dew from being condensed on recording layers 2, so errors in the recording and reproduction of information are eliminated. The flank of the spacer 40 is roughened to increase its surface area, so that no dew is condensed on the recording layers 2 even in case of large temperature variation. |
