| 摘要 |
PURPOSE:To attain good erasing under specified conditions in the case of using the disk under the conditions of the constant rotating speed by providing a metallic reflecting layer and increasing the film thickness thereof from the outer periphery to the inner periphery of the disk. CONSTITUTION:This disk is formed by successively laminating a 1st dielectric layer 2, a recording layer 3, a 2nd dielectric layer 4 and the metallic reflecting layer 5 on a substrate 1. The film thickness of the reflecting layer 5 is increased from the outer periphery toward the inner periphery of the disk to obtain the optical disk which varies in cooling rate in a radial direction. The cooling rate is, thereupon, controlled by changing the film thickness of the reflecting layer 5. The equal cooling conditions are thus obtd. even at the different line speeds. Good erasing is executed in this way without changing the erasing conditions in accordance with the radial position of the disk. |
