| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an information recording medium which can secure a sufficient tilt margin and sufficient mechanical strength even when recording density is enhanced. <P>SOLUTION: The information recording medium is equipped with a substrate having a recording surface formed with an embossed pit or a guide groove, a reflective film formed on a recording surface on this substrate, and a first protecting film formed on this reflective film. Two planes composed of a first surface constituting the uppermost surface of the first protecting film and a second surface facing the first surface constitute the surface of the information recording medium. With the first surface being as an optical irradiation surface, the optical irradiation surface is irradiated with an optical beam, and recording information is reproduced based on a change of light intensity in the reflected light. A distance between the recording surface of the substrate and the optical irradiation surface is smaller than the thickness of the substrate, and the roughness of the surface of the optical irradiation surface is less than λ/(8n) (λ is the wavelength of the optical beam, and n is an optical refractive index of the first protecting film for the light of the wavelength λ). <P>COPYRIGHT: (C)2005,JPO&NCIPI |
