| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that a conventional multilayer optical information recording medium has the possibility of being affected by the nearer information layer in the case of recording the farther information layer as viewed from a laser incidence side. <P>SOLUTION: An optical information recording medium having two information layers 2 and 3 wherein the irradiation of either the information layer with a laser beam converging thereon causes information signals to be recorded or reproduced; the nearer positioned information layer than the farthest information layer as viewed from the incidence side of the laser beam has a recording layer varying between two optically detectable states, and 0<=¾T<SB>c</SB>-T<SB>a</SB>¾/T<SB>c</SB><=0.1 where Tc is the transmittance of the nearer positioned information layer when the recording layer is in state (a) and Ta, the transmittance, when it is in state (b). This makes it possible to accurately record and reproduce information onto and out of the farther information layer irrespective of whether or not any information is recorded on the nearer information layer. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
