| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk in which reproduction or recording/reproduction of data of CD, DVD and BD standards can be performed from one side. <P>SOLUTION: In the optical disk having a first information layer wherein reproduction or recording/reproduction is performed with a laser beam having 300 to 600 nm wavelength, a first semi-transparent reflection layer, a second information layer wherein reproduction or recording/reproduction is performed with a laser beam having 600 to 700 nm wavelength, a second semi-transparent reflection layer, and a third information layer wherein reproduction or recording/reproduction is performed with a laser beam having 700 to 900 nm wavelength in order from a laser beam incident surface, the first semi-transparent reflection layer has ≥20% reflectance to the beam having 300 to 600 nm wavelength and ≥40% transmittance to the beam having 600 to 900 nm wavelength and the second semi-transparent reflection layer has ≥30% reflectance to the beam having 600 to 700 nm wavelength and ≥50% transmittance to the beam having 700 to 900 nm wavelength. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
