Patent ID: 8580368

Claim:
An information recording medium comprising three or more information layers and being capable of recording and reproducing information by irradiation with light, which is characterized in that at least one information layer provided on the light incident side is an information layer capable of overwriting information and comprises at least a recording film, a transmittance adjusting film of a dielectric comprising Bi, Ti and O, and an isolation film in this order from the light incident side; the isolation film is provided between and adjacent to the transmittance adjusting film and an intermediate separation layer that separates the information layer from another information layer on the side opposite to the light incident side; the isolation film has an optical constant at a wavelength of 405 nm such that a refractive index is 1.8 or less and an extinction coefficient is 0.05 or less; and the isolation film comprises at least one compound selected from oxides and complex oxides of at least one element selected from Si, Al and Mg and fluorides of at least one element selected from La and Ce in an amount more than 50 mol %.