OPTICAL INFORMATION RECORDING MEDIUM

摘要

PURPOSE:To decrease the noise level in the stage of recording and reproducing by using a high-density energy beam such as laser light and to obtain a recording medium having a high reproduction S/N ratio by specifying the center line average roughness at the boundary face of an optical reflective recording layer to a specific value or below. CONSTITUTION:A coating liquid prepd. by adding a film hardening agent to an aq. hydrophilic colloid soln. contg. pulverous particles of, for example, palladium sulfide having about 30Angstrom average grain size as a nucleus depositing agent is coated on a transparent base 1 and is dried to provide a deposition layer 2 having <=0.001mu Ra center line average roughness and about 10<19> pieces/cm<2> deposited nucleus density. A gelatin soln. contg. cuprous salt such as CuCl2 or CuI2 is preferably coated thereon and is dried to form a Cu compd. -contg. layer 3. The entire part is then dipped into a deposition treating liquid such as aq. glycine liquid adjusted to 9pH to migrate and deposit Cu from the layer 3 onto the nuclei of the layer 2. The layer 5 (the layer 3 before the deposition) is removed after the end of the deposition and the recording medium having an optical recording layer 4 (the layer 2 before the deposition) of <=0.025mu Ra in the center line roughness at the boundary face of the layer 4 is obtd. The recording medium which permits the recording and reproduction at the high S/N ratio by the irradiation of the laser beam 6 is thus obtd.