| 摘要 |
PURPOSE:To obtain an information signal recording medium which is provided with the advantages of the LV and differential systems, by specifying the widths of its pits. CONSTITUTION:Out of the pits to be recorded on an information signal recording medium, pits Pl having pit lengths corresponding to almost a half of the longest recording wavelength Al are provided in such a way that their pit widths W1 are set to the 1st pit width W1 which is smaller than the diameter (d) of a light spot 1. It is desirable to set the 1st pit width W1 to about 1/3 of the diameter (d) of the light spot 1 when the diameter (d) of the light spot 1 is set to d=0.82lambda/NA (where, lambda is the wavelength of light, NA is the numerical aperture of the lens forming the light spot). |
