Abstract: An information recording medium including a transparent substrate, and a recording layer or a metallic layer formed on the transparent substrate directly or through an undercoat layer, with an amplitude attenuation time of 1 second or less and/or a vibration frequency attenuation time of 3 seconds or less, when vibrated in the direction perpendicular to the flat surface of said information recording medium, or wherein when the information recording medium is in-plane vibrated in the direction perpendicular to the extending direction of information recording, reproducing and/or deleting tracks, a maximum in-plane deviation of a recording, reproducing or deleting position in the tracks in the perpendicular direction from a correct recording, reproducing or deleting position in the tracks is 12.

Abstract: An information recording medium includes a transparent substrate and a recording layer or a metal layer provided on the transparent substrate directly or via a ground layer. The information recording medium has a RAM area on which information is recorded, reproduced or erased, and a ROM area from which only reproduction is made, and an average thickness of the recording layer of said RAM area is larger than that of the recording layer or metal layer of the ROM area.

Abstract: An information recording medium including a transparent substrate, and a recording layer or a metallic layer formed on the transparent substrate directly or through an undercoat layer, with an amplitude attenuation time of 1 second or less and/or a vibration frequency attenuation time of 3 seconds or less, when vibrated in the direction perpendicular to the flat surface of said information recording medium, or wherein when the information recording medium is in-plane vibrated in the direction perpendicular to the extending direction of information recording, reproducing and/or deleting tracks, a maximum in-plane deviation of a recording, reproducing or deleting position in the tracks in the perpendicular direction from a correct recording, reproducing or deleting position in the tracks is 12.

Abstract: A desired writable optical data recording medium has a transparent substrate 1 where a side wall of a recess is connected to a land surface by a curved surface. A data recording portion of a dye material may be placed only in recesses of a pre-formatted pattern on a transparent substrate, and a reflective layer may be formed on the data recording portion and on the exposed land area between neighboring recesses. The medium can show reflectivity of not less than 65% on reproduction and reduce the cost for manufacturing thereof.

Abstract: An apparatus for producing an optical data recording medium comprising a turn table adapted to support a substrate of the recording medium and a nozzle for dropping a coating liquid onto the substrate, the coating liquid dropped on the substrate being spread over the substrate by a rotational force of the turn table to form a coating layer, the apparatus being provided with a gas flow suppressing type housing which is partitioned off from the atmosphere so as to suppress the convection current flowing, due to the rotation of the turn table, toward a central portion of the substrate and further toward the outer circumferential portion thereof along a top surface of the substrate and to suppress the evaporation of a solvent of the coating liquid into the atmosphere, the nozzle being arranged above the inner circumferential portion of the substrate with its end portion being directed to the outer circumferential portion of the substrate, the end portion of the nozzle being inclined so as to form an angle less th

Abstract: An optical data recording medium having a recording layer with or without an underlayer layered on a transparent substrate, wherein said recording layer is composed of a difficult-to-dissolve-in-water organic dye type material on which a thin layer composed of a surface active polymer as a hydrophilic material, which is denaturated by cross-linking.

Abstract: An optical data recording medium provided with a recording layer, the recording medium having excellent durability to light and heat, superior writing sensitivity and a high C/N value, wherein at least one a group of anion selected from a group of hexafluorophosphate ion (PF.sub.6 .sup.-), trifluoromethane sulfonate ion (CF.sub.3 SO.sub.3 .sup.-) or thiocyanate ion (SCN.sup.-) is present as the anion in an indol cyanine dye having a methyne chain present in the recording layer of the optical data recording medium.

Abstract: A write-once type filled up with any fillers optical data recording medium provided with recording layers for a melting and diffusion recording system is disclosed, wherein a protective layer is formed between the recording layers or between the recording layer and another plate shaped member, the protective layer being composed of a member which is not adversely effected by a melting and recording operation and is not warped by changes of external conditions.