An optical recording medium includes a plurality of information signal layers. The plurality of information signal layers include a recording layer having a first surface that faces a light irradiation surface and a second surface on the side opposite to the first surface, a first dielectric layer that is provided on the side of the first surface, and a second dielectric layer that is provided on the side of the second surface. The second dielectric layer provided in the information signal layer positioned on the innermost side when viewed from the light irradiation surface contains indium oxide and tin oxide. The recording layer provided in the information signal layer positioned on the innermost side when viewed from the light irradiation surface contains an oxide of a metal MA, an oxide of a metal MB, an oxide of a metal MD, and an oxide of a metal ME, the metal MA is at least one selected from the group consisting of Mn and Ni, the metal MB is at least one selected from the group consisting of W, Mo, Zr and Ta, the metal MD is at least one selected from the group consisting of Cu and Ag, the metal ME is Nb, the contents of the metal MA, the metal MB and the metal ME satisfy the relationship of 0.30≤a.sub.1/(b.sub.1+e.sub.1)≤0.41 (where, a.sub.1: atomic ratio [atomic %] of the metal MA with respect to a total amount of the metal MA, the metal MB, the metal MD and the metal ME, b.sub.1: atomic ratio [atomic %] of the metal MB with respect to a total amount of the metal MA, the metal MB, the metal MD and the metal ME, and e.sub.1: atomic ratio [atomic %] of the metal ME with respect to a total amount of the metal MA, the metal MB, the metal MD and the metal ME), and the atomic ratio e.sub.1 of the metal ME with respect to a total amount of the metal MA, the metal MB, the metal MD and the metal ME is 5 atomic % or more and 18 atomic % or less.

An information recording medium and a method for producing the same according to the present disclosure are configured to have an information layer in which a larger amount of light for reproduction can be obtained, so that the medium is suitable for recording information at high recording density and is useful for a multi-layer optical disc that records a large amount of contents.

A sintered compact target containing an element(s) (A) and an element(s) (B) as defined below is provided. The sintered compact target is free from pores having an average diameter of 1 μm or more, and the number of micropores having an average diameter of less than 1 μm existing in 40000 μm.sup.2 of the target surface is 100 micropores or less. The element(s) (A) is one or more chalcogenide elements selected from S, Se, and Te, and the element(s) (B) is one or more Vb group elements selected from Bi, Sb, As, P, and N. The provided technology is able to eliminate the source of grain dropping or generation of nodules in the target during sputtering, and additionally inhibit the generation of particles.

Provided is a Mn—Ta—W—Cu—O-based sputtering target including, in the component composition, Mn, Ta, W, Cu, and O. The sputtering target has a relative density of at least 90%, and includes a crystal phase of Mn.sub.4Ta.sub.2O.sub.9. Also provided is a production method for the sputtering target.

An information recording medium and a method for producing the same according to the present disclosure are configured to have an information layer in which a larger amount of light for reproduction can be obtained, so that the medium is suitable for recording information at high recording density and is useful for a multi-layer optical disc that records a large amount of contents.

Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.

An information recording medium includes three or more information layers. The three or more information layers include a first information layer including a first dielectric film, a recording film, and a second dielectric film in this order. The first dielectric film contains an oxide of D1. The D1 represents at least one element selected from a first group consisting of Nb, Mo, Ta, W, Ti, Bi, and Ce. The recording film contains at least W, Cu, Mn, and oxygen and M. The M represents at least one element selected from a second group consisting of Nb, Mo, Ta, and Ti. The W, the Cu, the Mn, and the M except the oxygen in the recording film satisfy a following formula (1):

W.sub.xCu.sub.yMn.sub.zM.sub.100-x-y-z (atom %)(1) wherein x, y, and z satisfy 15x60, yz, 0<z40, and 60x+y+z98.

Provided is an optical recording medium including two or more recording layers, and a light irradiation surface that is irradiated with light for recording an information signal on the two or more recording layers. Among the two or more recording layers, at least one layer other than a layer located on the deepest side from the light irradiation surface includes an oxide of a metal A, an oxide of a metal B, and an oxide of a metal C. The metal A is at least one kind among W, Mo, and Zr, the metal B is Mn, and the metal C is at least one kind among Cu, Ag, and Ni. Ratios of the metal A, the metal B, and the metal C satisfy a relationship of 0.46x1 (provided that, x1=a/(b+0.8c), a representing an atomic ratio [atom %] of the metal A with respect to the sum of the metal A, the metal B, and the metal C, b representing an atomic ratio [atom %] of the metal B with respect to the sum of the metal A, the metal B, and the metal C, and c representing an atomic ratio [atom %] of the metal C with respect to the sum of the metal A, the metal B, and the metal C.

An optical recording medium includes a light-receiving surface that receives incident light and at least three information signal layers on which information signals are to be optically recorded. Among the at least three information signal layers, the information signal layer closest to the light-receiving surface has a reflectance in a range of 4% to 11%.

An optical recording medium includes a plurality of information signal layers on which information signals are to be optically recorded. Among the plurality of information signal layers, the information signal layer closest to the light-receiving surface has a reflectance of more than 4%.