Optical information medium

摘要

An optical information medium is provided which has a light-transmitting substrate which exhibits excellent light transmittance when a laser beam of blue/violet region or ultraviolet region is used as the recording and/or reading beam; whose light transmittance is not substantially affected by the variation or fluctuation of the oscillation wavelength of the laser beam source; which has a long-term weatherability; and which exhibits sufficient protective effects against exterior impacts. The optical information medium comprises an information recording layer (4) and a light-transmitting substrate (2), and the medium is used such that the recording and/or reading laser beam reaches said information-recording layer through said light-transmitting substrate. The light-transmitting substrate has a light transmittance T and difference DELTA T between the maximum value and the minimum value of the light transmittance T in arbitrary wavelength range of 10 nm which satisfies the relations: T ≥ 0.8 and DELTA T ≤ 0.10 at least in the wavelength region of 250 to 450 nm. <IMAGE>