| 摘要 |
PURPOSE:To improve recording density and reliability of information recording by specifying the range of thickness ratio of a recording material layer to an outer protective layer. CONSTITUTION:A transparent substrate 103 on which laser light through a condensor lens 102 is made incident has plural tracking guide grooves 109. On the surface of the transparent substrate 103 where the guide groove 109 is formed, an inner protective layer 104, recording material 105, outer protective layer 106, metal reflecting film layer 107, and disk protective layer 108 are formed. Because it is required that in this film structure, enough temp. rising for recording is obtd. in a narrow area by irradiation of light for recording, the inner and outer protective layers 104, 105 are specified to have 100nm, 200nm thickness, respectively, and the reflecting layer 107 has 100nm thickness. Further, the ratio of thickness of the recording material layer 105 to the outer protective layer 104 is specified to a range between >0.52 and <0.95. Thus, the recording density can be improved. |
