Optical information recording medium and method for initializing the same

A method for initializing an optical information recording medium by radiating a laser beam,

• the recording medium including a substrate and at least a first information layer and a second information layer, the first information layer and the second information layer, on/from which signals can be recorded/reproduced, being formed on the substrate in this order,
• the laser beam being radiated from a side of the substrate,
• wherein, at least in an area where both the first and second information layers are formed, the first information layer is initialized after the second information layer is initialized,
• with respect to a laser beam having a wavelength of λ1 for initializing the first information layer, a reflectance R1(1before) of the first information layer before being initialized, a reflectance R1(2before) of the second information layer before being initialized, a reflectance R1(2after) of the second information layer after being initialized, and a transmittance T1(1before) of the first information layer before being initialized, and
• with respect to a laser beam having a wavelength of λ2 for initializing the second information layer, a reflectance R2(1before) of the first information layer before being initialized, a reflectance R2(2before) of the second information layer before being initialized, and a transmittance T2(1before) of the first information layer before being initialized, satisfy the relationships:
• R1(1before)<R1(2before)×[T1(1before)]2, R1(2before)>R1(2after), and R2(1before)<R2(2before)×[T2(1before)]2.

A method for initializing an optical information recording medium by radiating a laser beam,

• the recording medium including a substrate and at least a first information layer and a second information layer, the first information layer and the second information layer, on/from which signals can be recorded/reproduced, being formed on the substrate in this order, wherein an area where the first information layer exists and the second information layer does not exist is provided on the substrate,
• the laser beam being radiated from a side of the substrate,
• wherein initialization of the first information layer is started from the area, and
• the first information layer is initialized after the second information layer is initialized at least in an area where both the first and second information layer are formed.

A method for initializing an optical information recording medium,

• the recording medium including a substrate and at least a first information layer and a second information layer, the first information layer and the second information layer, on/from which signals can be recorded/reproduced, being formed on the substrate in this order,
• wherein the first and second information layers are initialized by at least one flash light radiated from a light source provided on the side of the substrate,
• the first and second information layers are initialized at the same time by a flash light with an emission time of not more than 200 μs radiated once, and
• the flash light passes through the first information layer at a transmittance of not less than 40% and not more than 70%.