Abstract: An optical information recording and/or reproducing apparatus comprises: a focusing unit (11) which collects generated near-field light on an optical disc (1); a first detector (17) which receives light reflected by the optical disc (1) and outputs an electric signal according to the quantity of the received light; and a distance control circuit (22) which controls the distance between the focusing unit (11) and a light entrance surface of the optical disc (1), using the electric signal that is output from the first detector (17), and the optical disc (1) has at least N (N is an integer of 2 or greater) number of information layers, and a distance d0 from the light entrance surface to a first information layer which is most distant from the light entrance surface and a distance dn from the light entrance surface to an Nth information layer which is closest to the light entrance surface satisfy the relationship of dn?d0×(1/25).

Abstract: An information recording medium of the present invention includes N information layers on a substrate (1), where N is an integer of 2 or more. Information is recorded/reproduced by irradiating each of the information layers (11, 12) with a laser beam (4). When the N information layers are referred to as a first information layer to an N-th information layer sequentially from the opposite side to a laser beam incident side, the L-th information layer included in the N information layers includes at least a recording layer (135) capable of undergoing a phase change through laser beam irradiation, a reflective layer (132), and a transmittance adjusting layer (131) in this order from the laser beam incident side, where L is an integer satisfying 2?L?N. The transmittance adjusting layer (131) contains Nb, oxygen (O), and at least one element M selected from Ti, Zr, Hf, Y, Cr, Zn, Ga, Co, Bi, In, Ta, and Ce. In the transmittance adjusting layer (131), the content of Nb is at least 2.9 atom %.

Abstract: An information recording medium, 15 capable of recording information by irradiation of light or applying electrical energy, wherein at least one of first and second dielectric layers 102, 106, first interface layer and counter-incident side interface layer 103, 105 is formed from a Si—In—Zr/Hf—O-based material containing at least Si, In, M1 (M1 represents at least one element selected from among Zr and Hf) and oxygen (O), with Si content being 1 atomic % or more. This medium has high recording sensitivity when information is recorded thereon, high overwrite cycle-ability and high signal intensity.

Abstract: According to the present invention, a recording film is partially initialized using a first light beam (A) having a wavelength for initialization, focus adjustment is performed using a second light beam (B) having a wavelength corresponding to a wavelength for recording and reproducing information on and from an information recording medium, and then the recording film is initialized using the first light beam (A), thereby it is possible to securely initialize recording films of all information layers of a multilayer information recording medium.

Abstract: An information recording medium of the present invention includes a recording layer whose phase changes by irradiation with a laser beam or application of current. The recording layer contains, as its main component, a composite composed of Ge and Sb that are essential components, and Te that is an optional component. The composite has a composition within a region enclosed by: point (a) (35, 65, 0), point (b) (36.9, 60, 3.1), point (c) (3.2, 60, 36.8), and point (d) (5, 95, 0) in terms of a coordinate (Ge, Sb, Te)=(x, y, z) on the triangular coordinate shown in FIG. 1, where point (b) corresponds to a point at Sb=60 on Ge60Te40—Ge35Sb65, point (c) corresponds to a point at Sb=60 on Te—Ge5Sb95, and the region includes lines extending between point (a) and point (b), point (b) and point (c), point (c) and point (d), and point (d) and point (a).

Abstract: An information recording medium of the present invention includes recording layers 19 and 26 whose phase can change by an optical or an electrical system so as to be detectable, and interface layers 18, 20, 25 and 27, which are in contact with the recording layers 19 and 26, to serve as oxide layers. The recording layer 19 contains a Ge—Bi—Te-M material represented by a formula: Ge?Bi?Te?M100-?-?-? (atom %), where M denotes at least one element selected from Al, Ga, In and Mn, and ?, ? and ? satisfy 25???60, 0<??18, 35???55, and 82??+?+?<100. The interface layers 18, 20, 25 and 27 contain at least one oxide of the element M contained in the recording layers 19 and 26.

Abstract: The information recording medium (1) of the present invention includes a recording film (114, 124). The information recording medium (1) allows information to be recorded and reproduced on and from the information recording medium by irradiation of the recording film (114, 124) with a laser beam (18). The information recording medium (1) of the present invention further includes a mixed dielectric film (the second dielectric film 116, 126) disposed on the laser beam (18) incident side with respect to the recording film (114, 124). The mixed dielectric film contains a mixed dielectric material consisting of Zn sulfide, Si oxide and an oxide X (where the oxide X is an oxide of at least one element selected from Ti, Nb, Ta and Ce).

Abstract: The information recording medium of the present invention comprises at least one of the following oxide-based material layers: (I) an oxide-based material layer containing Zr, at least one element selected from the group GL1 consisting of La, Ga and In, and oxygen (O); (II) an oxide-based material layer containing M1 (where M1 is a mixture of Zr and Hf, or Hf), at least one element selected from the group GL2 consisting of La, Ce, Al, Ga, In, Mg and Y, and O; (III) an oxide-based material layer containing at least one element selected from the group GM2 consisting of Zr and Hf, at least one element selected from the group GL2, Si, and O; and (IV) an oxide-based material layer containing at least one element selected from the group GM2, at least one element selected from the group GL2, Cr, and O. This oxide-based material layer can be used, for example, as a dielectric layer.

Abstract: An information recording medium (9) of the present invention is an information recording medium with respect to which information can be recorded or reproduced by irradiation with an optical beam (1). The information recording medium (9) includes a second interface layer (103), a recording layer (104) and a first interface layer (105) in this order from the optical beam (1) incident side. The first interface layer (105) and the second interface layer (103) are disposed in contact with the recording layer (104). The second interface layer (103) contains M1 (where M1 is at least one element selected from Nb, Y, Dy, Ti, Si and Al), Cr and oxygen (O). The first interface layer (105) contains M2 (where M2 is at least one element selected from Nb, Y, Dy, Ti, Si, Al, Zr and Hf), Cr and oxygen (O). The first interface layer (105) and the second interface layer (103) each contain Cr in a range of 50 mol % or less in terms of the oxide (Cr2O3).

Abstract: In an information recording medium that has an information layer which includes a recording layer capable of undergoing phase transition, the recording layer is formed from a material that contains Sb and S, and has composition represented by the formula (1): SbxS100-x (atomic %) where suffix x represents the proportion in atomic % that satisfies a relationship of 50?x?98.

Abstract: An information recording medium (300) of the present invention is an information recording medium on or from which information can be recorded or reproduced by irradiation with an optical beam (10), and includes a dielectric layer b, a recording layer (335), and a dielectric layer a in this order from an optical beam (10) incident side. The dielectric layer a and the dielectric layer b are layers disposed in contact with the recording layer (335), and an interface layer (334) corresponds to the dielectric layer a and an interface layer (336) corresponds to the dielectric layer b. The dielectric layer a contains Cr, O, and at least one element M selected from Al, Dy, Nb, Si, Ti and Y. The dielectric layer b contains Cr, O, and at least one element A selected from Zr and Hf.

Abstract: In each of at least two information layers (1, 2) which constitute a information recording medium having a plurality of information layers on its one side, the compositions of the recording layer (7) and the dielectric layers (6, 8) adjacent to the recording layer (7) in one information layer (1) are common to the compositions of the corresponding layers (12, 11, 13) in the other information layer, so that the recording layers (7, 12) and the dielectric layers (6, 11) and (8, 13) in the two information layers (1, 2) can be formed in common sputtering film-forming chambers without the replacement of targets, which makes it possible to produce a multi-layer single-sided recording medium with a decreased time loss in the production process.

Abstract: The information recording medium of the present invention includes a recording layer whose phase can be changed by application of electrical energy. The recording layer contains, as a main component, a material consisting of Ge, Te, and Sb. The material has a composition within a region defined by point (a) (35, 35, 30), point (b) (32.5, 27.5, 40), point (c) (25, 25, 50), and point (d) (27.5, 32.5, 40) and including lines from point (a) to point (b), from point (b) to point (c), from point (c) to point (d), and from point (d) to point (a), respectively, when coordinates (Ge, Te, Sb)=(x, y, z) are plotted on a triangular coordinate system shown in FIG. 1.

Abstract: An optical information recording and/or reproducing apparatus comprises: a focusing unit (11) which collects generated near-field light on an optical disc (1); a first detector (17) which receives light reflected by the optical disc (1) and outputs an electric signal according to the quantity of the received light; and a distance control circuit (22) which controls the distance between the focusing unit (11) and a light entrance surface of the optical disc (1), using the electric signal that is output from the first detector (17), and the optical disc (1) has at least N (N is an integer of 2 or greater) number of information layers, and a distance d0 from the light entrance surface to a first information layer which is most distant from the light entrance surface and a distance dn from the light entrance surface to an Nth information layer which is closest to the light entrance surface satisfy the relationship of dn?d0×(1/25).

Abstract: An optical information recording medium (100) of the present invention includes an information layer (011) that allows information to be recorded thereon and reproduced therefrom by irradiation with a laser beam (040). The information layer (011) includes a reflective layer (002), a first dielectric layer (003), a recording layer (005) capable of undergoing a phase change by the irradiation with the laser beam (040) and a second dielectric layer (007) formed in this order from a side opposite to a laser beam incident side. The recording layer (005) contains Ge, Sb and Te. When Ge, Sb and Te contained in the recording layer (005) are represented by GexSbyTez in atomic number ratio, x, y, and z satisfy 0.39?x?0.48, 0.02?y<0.11, 0.40?z<0.56, and x+y+z=1. The recording layer (005) has a thickness of at least 10 nm but not more than 15 nm.

Abstract: The present invention provides an information recording medium with high reliability and excellent repeated rewriting performance even when no interface layer is formed and a method for manufacturing the same. Accordingly, the information recording medium for carrying out recording and/or reproducing by light irradiation or electric energy application has a material layer containing at least one element selected from a group GM consisting of Sn and Ga, at least one element selected from a group GL consisting of Ta and Y, and oxygen.

Abstract: There is provided a dielectric material containing no sulfur (S), and there is provided an information recording medium that affords high signal quality and excellent recording sensitivity and repeated rewrite characteristics, even though no interface layer is provided between a reflective layer and a dielectric layer. To this end, the present invention is an information recording medium that is equipped with at least a recording layer and undergoes phase change when the recording layer is irradiated with a laser beam or when current is applied, comprising an oxide-fluoride dielectric layer that includes indium (In), an element M1 (where M1 is at least one element selected from among Zr, Hf, Y, Ti, Nb, Ta, Cr, Ga, and Si), oxygen (O), an element M2 (where M2 is at least one element selected from among La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Yb, Mg, Ca, and Sr), and fluorine (F).

Abstract: An information recording medium ensuring high recording and erase function and excellent archival characteristic at a high linear velocity and over a wide range of linear velocities is provided. Such a medium is obtained by constructing a recording layer which has a composition that can generate phase change as a whole, of a first through an M-th constituent layers (wherein M is an integer of 2 or greater) which are stacked in a thickness direction, such that elemental compositions of contiguous an m-th constituent layer and a (m+1)th constituent layer are different from each other (wherein m is an integer and satisfies 1?m?M) assuming that the constituent layer located at an m-th position from a laser light incident side is the m-th constituent layer. In this information recording medium, at least one m-th constituent layer constituting the recording layer preferably includes at least one element selected from Te, Bi, Sb, Ge, In, Ga, Al, Sn, Pb, Se and Si.

Abstract: An information recording medium includes a substrate and an information layer formed on the substrate. The information layer includes a recording layer whose phase can be changed between a crystalline phase and an amorphous phase by irradiation with a laser beam or application of electric energy; a Cr-containing layer including at least Cr and O, arranged in contact with a first surface of the recording layer; and a Ga-containing layer including at least Ga and O, arranged in contact with a second surface of the recording layer.

Abstract: An information recording medium with high recording sensitivity, superior repeat overwriting capability and favorable signal storage stability during information recording is offered. For this purpose, an information recording medium comprises one or more information layers that include a phase-change recording layer, wherein at least one of the information layers includes, a Cr-containing layer containing Cr and O that contact with one side of a surface of the recording layer, and an In-containing layer containing In and O that contact with the other side of the surface of the recording layer.