Optical type information recording medium having specified pit and guide groove shapes

摘要: An optical type information recording medium has guide grooves for tracking formed in a concentric or spiral shape at predetermined pitch; and pre-format pit approximately midway between the normal direction thereof least address information. The is constructed such that pitch value ranged from 1.4 μm to 2.0 μm, depth of 0.46 λ/n 0.58 where n shows refractive index substrate λ wavelength light source reading recorded medium, cross-sectional provided range represented by first inequality using function second degree, degree.