Abstract: [Object] To provide an optical recording medium that can be applied to a write-once optical recording medium having a high capacity of about 25 GB per one layer, and has good recording properties when a multilayered recording layer configuration is provided. [Solving Means] It includes a substrate 21 and two to four recording layers 221 and 222. At least one or more of these recording layers 221 and 222 are specific recording layers with a composition containing PdO and PdO2 as well as at least one of completely oxidized In, Zn, Al and Sn (in other words, In2O3, ZnO, Al2O3 and SnO2). Adjacent to the specific recording layers, dielectric layers 232a and 232b of In/Al oxide layers containing at least either of In or Al as a main component are disposed.

Abstract: An object of the invention is to provide an optical recording medium and a method for producing an optical recording medium that enable to improve the quality of a servo signal and a reproduction signal. The optical recording medium satisfies: t3?t4?1 ?m, t4?t2?1 ?m, t2?10 ?m, and t1?(t2+t3+t4)?1 ?m, where t1 is a thickness between a surface of the optical recording medium, and the first information recording surface, t2 is a thickness between the first optical recording surface and the second information recording surface, t3 is a thickness between the second optical recording surface and the third information recording surface, and t4 is a thickness between the third optical recording surface and the fourth information recording surface.

Abstract: An optical recording medium having three or more information recording layers reduces crosstalk caused by multi-reflected beams and improves signal quality. In the optical recording medium having three or more information recording layers, the refractive index of a plurality of intermediate layers disposed between adjacent information recording layers is greater than the refractive index of a cover layer disposed between a light incident surface and an information recording layer being the closest from the light incident surface.

Abstract: An optical information recording medium in which recorded information is stably stored for long time in the initial state, signals are not deteriorated by a laser beam for reproduction at the time of signal reproduction, the quality does not change in normal long-term storage, the write characteristic is held, a manufacturing cost is reduced, a margin in the manufacture process is assured, and excellent recording/reproducing characteristics are obtained in the wide range of linear speeds and recording powers is provided. An optical information recording medium 1 is formed by sequentially stacking a first information recording layer 11, an intermediate layer 12, a second information recording layer 13, and a protection layer 14 on a substrate 10. As a material of a recording layer 13b of the second information recording layer 13, a material having a composition expressed by [(ZnS)x(SiO2)1-x]y(SbzX1-z)1-y (where 0<x?1.0, 0.3?y?0.7, 0.8?z?1.

Abstract: An object of the invention is to provide an optical recording medium and a method for producing an optical recording medium that enable to improve the quality of a servo signal and a reproduction signal. The optical recording medium satisfies: t3?t4?1 ?m, t4?t2?1 ?m, t2?10 ?m, and t1?(t2+t3+t4)?1 ?m, where t1 is a thickness between a surface of the optical recording medium, and the first information recording surface, t2 is a thickness between the first optical recording surface and the second information recording surface, t3 is a thickness between the second optical recording surface and the third information recording surface, and t4 is a thickness between the third optical recording surface and the fourth information recording surface.

Abstract: An optical information recording medium 1 is constructed by sequentially layering a reflective layer 11, a protective layer 12, a recording layer 13, a protective layer 14, and a light transmissive protective layer 15 on a substrate 10. As the recording layer 13, a recording layer containing ZnS, SiO2, and Sb as principal components, or preferably, a recording layer expressed by a compositional formula [(ZnS)x(SiO2)1-x]y(SbzX1-z)1-y (where 0<x?1.0, 0.3?y?0.7, and 0.8<z?1.0 are met and X denotes at least one element selected from a group of Ga, Te, V, Si, Zn, Ta, and Tb) is adopted.