Abstract: An optical recording medium includes a recording layer including a reflective layer, two dielectric layers, and a phase-change recording layer. The phase-change recording layer-side dielectric layer of the two dielectric layers contains tantalum oxide or a composite oxide composed of silicon oxide, indium oxide, and zirconium oxide. The reflective layer-side dielectric layer of the two dielectric layers contains a composite oxide composed of silicon oxide, indium oxide, and zirconium oxide, a composite oxide composed of indium oxide and gallium oxide, or a composite oxide composed of zinc oxide and aluminum oxide.

Abstract: The present application discloses an information device for performing optical information processes for a recording medium including a phase-change recording layer which becomes amorphous under irradiation with pulsed amorphization light that has prescribed amorphization energy Ew. The information device includes an irradiator configured to irradiate a prescribed region of the phase-change recording layer with pulsed light and an energy setting portion which sets crystallization energy Ee for the pulsed light to crystallize the prescribed region. The crystallization energy Ee per the pulsed light, which is set by the energy setting portion, is greater than the amorphization energy Ew per the pulsed amorphization light.

Abstract: An optical recording medium includes a recording layer including a reflective layer, two dielectric layers, and a phase-change recording layer. The phase-change recording layer-side dielectric layer of the two dielectric layers contains tantalum oxide or a composite oxide composed of silicon oxide, indium oxide, and zirconium oxide. The reflective layer-side dielectric layer of the two dielectric layers contains a composite oxide composed of silicon oxide, indium oxide, and zirconium oxide, a composite oxide composed of indium oxide and gallium oxide, or a composite oxide composed of zinc oxide and aluminum oxide.

Abstract: An optical information recording medium includes a recording film, which contains germanium, bismuth, and at least 50 at % tellurium, and has a first recording film component formed in the planar direction and having a bismuth content of at least 15 at %, a second recording film component formed in the planar direction on the side to be irradiated with a light beam and having a bismuth content that is at least 10 at % lower than that of the first recording film component, and an intermediate recording film component provided between the first and second recording film component to moderate the change in the bismuth content in the film thickness direction between the first and second recording film component, and having a bismuth content greater than the bismuth content of the second recording film component and less than the bismuth content of the first recording film component.

Abstract: A recording medium (10) is provided with a left-handed material layer (1) having at least one of a permittivity and a permeability of a negative value, and having substantially periodically formed structures; and a recording layer (2) including island-shaped and substantially periodically arranged recording regions (22), and being laminated on the left-handed material layer (1). The structure period of the left-handed material layer (1) is equal to or is an integral multiple of the arrangement period of the recording regions (22) of the recording layer (2).

Abstract: An information recording medium including three or more information layers, wherein: at least one information layer includes a recording layer and a nucleation layer; the recording layer contains a material that is represented by formula (1) [(Ge0.5Te0.5)x(In0.4Te0.6)1-x]ySb100-y (mol %) with x satisfying 0.8?x<1.0 and y satisfying 95?y<100; the nucleation layer contains a material that is represented by formula (2) (Ge0.5Te0.5)z(Bi0.4Te0.6)100-z (mol %) with z satisfying 10?z?71; and the nucleation layer is in contact with the recording layer. This information recording medium is capable of achieving sufficient signal amplitude even in cases where a small recording mark is formed, and is also capable of stably maintaining a small recording mark.

Abstract: An information recording medium (100) of the present invention includes a substrate (1) and a recording layer provided on the substrate (1) and having optical properties that can be changed by irradiation with a laser beam. The recording layer is formed of a plurality of arrayed minute recording regions (e.g., phase-change particles (2)). A part or all of the recording region is made of a recording material containing Te and O. The recording region has a length of 30 nm or less in an information recording direction. Preferably, the recording material further contains an element M, where M is at least one element selected from the group consisting of Pd, Au, and Pt.

Abstract: A multilayer-type optical recording medium having a translucent recording/reproducing functional layer containing a first protective layer, a second protective layer, a recording layer, a third protective layer, a reflective layer and a fourth protective layer in this order relative to incident laser light. The second protective layer and the fourth protective layer are made of the same kind of material. The refractive index of the second protective layer is higher by at least 0.3 than the refractive index of the first protective layer. When the film thickness of the second protective layer is set as D2, the film thickness of the fourth protective layer is set as D4, and the reflectivity before recording when the laser light is focused on the recording layer is set as R, the derivatives d(R)/d(D2) and d(R)/d(D4) have opposite signs from each other.

Abstract: A recordable information consists of a flat polycarbonate disk having two main faces and a light sensitive film covering one main face and on which information may be recorded. The film is multi-layered with at least two elementary superposed layer respectively containing one element A and one element B, one of the layers containing an element chosen in the Group IIIa, while the other layer contains an element chosen in Groups Va or VIa; or one of layers contains an element from Groups IIa or IIb while the other layer contains an element from Group VI. The thickness of each layer is nearly identical and the overall thickness of the light-sensitive film being at least equal to 35 nm. A burning process for safely and durably recording information on such a medium is also disclosed.

Abstract: An optical recording medium includes an inorganic recording layer, a first protective layer provided on at least one surface of the inorganic recording layer and containing indium oxide, and a second protective layer provided so as to be adjacent to the first protective layer and containing titanium oxide, zirconium oxide, or tin oxide.

Abstract: An optical recording medium includes a support substrate, and a semi-transmissive recording layer including a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase-change recording material layer, and a third dielectric layer which are laminated in that order from the support substrate side. The semi-transmissive semi-reflective layer is composed of silver, and the first dielectric layer includes a composite oxide layer using niobium oxide.

Abstract: An optical recording medium includes a support substrate and a semi-transmissive recording layer. The semi-transmissive recording layer includes a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase change recording material layer, and a third dielectric layer that are sequentially stacked in that order on the support substrate. The semi-transmissive semi-reflective layer contains silver. The second dielectric layer has a stack structure including a lower layer disposed at the interface on the semi-transmissive semi-reflective layer side and an upper layer disposed on the phase change recording material layer side of the lower layer. The lower layer is composed of indium oxide or a composite oxide of indium oxide and tin oxide. The upper layer is composed of tantalum oxide, gallium oxide, zirconium oxide, or niobium oxide.

Abstract: Disclosed herein is a recording material for an optical recording medium. The recording material has a composition represented by a general formula of BixGeyO(1-x-y), in which x and y respectively are atomic ratios of bismuth and germanium, and satisfy the requirements of the following formulae: 2.8?(x/y)?25 and 0.55?(1?x?y)?0.62.

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: An optical recording media includes a substrate, a cap layer opposite to the substrate, at least one first stacked recording structure, at least one second stacked recording structure, and a space layer. The first stacked recording structure including a first recording layer disposed between the substrate and the cap layer and a reflective layer disposed between the substrate and the first recording layer is disposed between the substrate and the cap layer. The second stacked recording structure including a second recording layer disposed between the substrate and the cap layer and an Nb2O5 interface layer disposed between the substrate and the second recording layer is disposed between the substrate and the cap layer. The spacer layer is disposed between the first and second stacked recording structures, the first stacked recording structures, and the second stacked recording structures. One of the first stacked recording structures is disposed directly on the substrate.

Abstract: A write-once optical recording medium includes an inorganic recording layer and a protective layer provided on at least one surface of the inorganic recording layer. This protective layer contains indium oxide and tin oxide as main components.

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: The recordable optical storage medium comprises a substrate layer, a data layer and a first and a second protection layer for the data layer, wherein the data layer comprises a semiconductor layer and a dopant layer with a doping material usable for doping the semiconductor layer. The semiconductor layer is in particular an intrinsic or essentially intrinsic semiconductor layer having a low reflectivity and the doping material of the dopant layer is selected such, that the reflectivity of the semiconductor layer is increased, when doping material of the dopant layer is diffused into the semiconductor layer.

Abstract: An optical information recording medium includes: a supporting substrate; a light-transmitting protective layer which becomes a layer on the incident side of recording and reproducing laser light; and an information recording layer intervening between the supporting substrate and the light-transmitting protective layer, wherein the information recording layer includes a phase-change material layer, a dielectric layer and a metal layer in this order from the incident side of laser light; and the dielectric layer is constituted of, as a main component, (In2O3)x(SnO2)1-x, wherein x is satisfied with the relationship of (0.4<x?0.7).

Abstract: An optical recording medium includes: a substrate; an information recording layer that is formed on the substrate and that has a recording film, which contains Zn or Al, Pd, and oxygen and in which the amount of oxygen is larger than that in a stoichiometric composition when Zn or Al is completely oxidized to become ZnO or Al2O3; and a light transmissive layer formed on the information recording layer.

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: An optical recording medium includes: a substrate; an information signal layer provided on the substrate; and a protective layer provided on the information signal layer. The information signal layer is provided with a reflecting layer, a recording layer provided on the reflecting layer and first, second and third dielectric layers laminated successively on the recording layer. Refractive indexes of the first, second and third dielectric layers are different from each other between the adjacent dielectric layers to each other. Among the first, second and third dielectric layers, the dielectric layer having the highest refractive index contains, as a main component, at least one member selected from the group consisting of titanium oxide, niobium oxide and a mixture of zinc sulfide and silicon oxide. The dielectric layer having the highest refractive index has a refractive index of 2.3 or more at a wavelength of 405 nm.

Abstract: Disclosed herein is an optical recording medium, including: a substrate; and an information recording layer formed on the substrate, an information signal being recorded and reproduced in and from the information recording layer by radiation of a light; wherein the information recording layer includes a reflecting layer, a dielectric layer formed on the reflecting layer, and a recording layer formed on the dielectric layer, the dielectric layer includes a first dielectric layer and a second dielectric layer, and a thermal conductivity of the second dielectric layer located on the reflecting layer side is higher than that of the first dielectric layer located on the recording layer side.

Abstract: An information recording medium (1) of the present invention is an information recording medium allowing information to be recorded thereon by irradiation with a laser beam or by application of electrical energy. The information recording medium (1) includes a recording layer (15) capable of undergoing a phase change by the irradiation with the laser beam or by the application of the electrical energy. The recording layer (15) contains Sb, Te, Ge, and C, and a content of Te in the recording layer (15) is at least 8 atom % but not more than 25 atom %.

Abstract: An information recording medium (9) comprises an information layer (9a) in which concavo-convex marks are formed, and a recording layer (13), contained within the information layer (9a), in which added marks are formed by optical properties changing through laser irradiation, and that contains Te, O, and M (where M is at least one element selected from a group consisting of Pd, Au, Pt, Ag, Cu, and Ni). In this information recording medium (9), a pre-laser irradiation reflectance Ra and a post laser irradiation reflectance Rb fulfill 1.0<Rb/Ra<1.1.

Abstract: An optical recording medium includes a substrate having features that define track regions, an optical recording layer disposed on the substrate, and a light-transmitting layer disposed on the optical recording layer. The optical recording layer has a composition of (Sb2Se3)wTexOyPdz, where w, x, y, and z each represent a molar percent and satisfy 10 (mol %)?w?60 (mol %), 0 (mol %)<x?60 (mol %), 30 (mol %)?y?60 (mol %), 10 (mol %)?z?30 (mol %), and w+x+y+z=100.

Abstract: An optical information recording medium is provided and includes a supporting substrate, a light-transmissive protective layer, information recording layers, and at least one interlayer transparent to a laser beam having a wavelength of 400 to 410 nm. Among the information recording layers, one or a plurality of information recording layers other than the information recording layer closest to the supporting substrate each function as a semi-transmissive information recording layer that transmits the laser beam. Some or all of the one or the plurality of semi-transmissive information recording layer include, from the laser beam incident side, a first dielectric portion having a refractive index of 2.4 or more for the wavelength of the laser beam, a recording material portion having a thickness of at least 5.2 nm, a second dielectric portion, a metal portion having a thickness of at least 7 nm, and a third dielectric portion in that order.

Abstract: In an optical disk including at least a rewritable phase change material and comprising a recording layer having a reflectivity of more than 15%, an address output value as an address pit signal component occupying in a reproduced signal in a non recording state is prescribed to be 0.18 though 0.27 or a numerical aperture of an address pit signal occupying in a reproduced signal in a non recording state is prescribed to be more than 0.3.

Abstract: An optical information recording medium (9) of the present invention is an optical information recording medium including: N information layers, where N is a natural number of 2 or more; and an intermediate layer for separating the N information layers optically from each other. With the N information layers being referred to as a first information layer (10) to an N-th information layer (7) sequentially from an optical beam incident side, a first information layer (10) corresponding to an L-th information layer included in the N information layers includes a recording layer (104) on which information can be recorded by irradiation with an optical beam, a reflective layer (108), and a transmittance adjusting layer (109) in this order from the optical beam incident side, where L is an at least one natural number that satisfies 1?L?N?1. The transmittance adjusting layer (109) contains tungsten (W) and oxygen (O).

Abstract: Provided is an optical recording medium comprising a substrate and a reflective layer, a first dielectric layer, a recording layer, a second dielectric layer and a light-transmission layer formed in this order on the substrate. The recording layer is decomposable by heat at a time of recording to achieve recording of the optical recording medium, and the optical recording medium further comprises a third dielectric layer between the second dielectric layer and the light-transmission layer.

Abstract: In an optical information recording medium of the present invention, at least one information layer provided on a transparent substrate includes a protective layer and a write-once recording layer that are disposed in this order from the transparent substrate side. The recording layer contains at least one selected from Cr—O, Zn—O, Ga—O, In—O, Sn—O, Sb—O, Bi—O, and Te—O. The protective layer contains at least one selected from Cr—O, Zn—O, Ga—O, In—O, Sn—O, Sb—O, Bi—O, and Te—O. When the total amount of all the atoms other than oxygen atoms contained in the protective layer is taken as 100 atom %, the total amount of atoms of Cr, Zn, Ga, In, Sn, Sb, Bi, and Te in the protective layer is at least 70 atom %.

Abstract: An information recording medium is provided that has high recording sensitivity and high erasability, even when a recording layer thereof is as thin as about 3 nm. An information recording medium 15 on which information can be recorded by applying light or electrical energy has at least a recording layer 104 that undergoes phase change, while the recording layer 104 contains at least one element selected from among Zn, Si and C, and Sb in total proportion of 85 atomic % or more and has a composition preferably represented by the formula Sb100-a1M1a1 (atomic %) (wherein M1 represents at least one element selected from among Zn, Si and C, and a1 is a proportion in terms of atomic % that satisfies a relationship of 0<a1?50).

Abstract: An optical information recording medium, recording/reproducing method thereof, and recording/reproducing apparatus with superior signal quality for high-density recording that has high storage reliability is provided. The optical information recording medium has at least one information layer having a recording layer and a dielectric layer in order on a transparent substrate. The dielectric layer is comprised of greater than or equal to 50 molecule percent and less than or equal to 98 molecule percent of Zn—O, and greater than or equal to 2 molecule percent to less than or equal to 50 molecule percent of one or more compounds selected from the group consisting of Y—O, Ce—O, Nb—O, Ta—O, Cr—O and Mo—O.

Abstract: An optical recording medium includes a support substrate and a semi-transmissive recording layer. The semi-transmissive recording layer includes a first dielectric layer, a semi-transmissive semi-reflective layer, a second dielectric layer, a phase change recording material layer, and a third dielectric layer that are sequentially stacked in that order on the support substrate. The semi-transmissive semi-reflective layer contains silver. The second dielectric layer has a stack structure including a lower layer disposed at the interface on the semi-transmissive semi-reflective layer side and an upper layer disposed on the phase change recording material layer side of the lower layer. The lower layer is composed of indium oxide or a composite oxide of indium oxide and tin oxide. The upper layer is composed of tantalum oxide, gallium oxide, zirconium oxide, or niobium oxide.

Abstract: A high density information storage medium includes a recording layer in which information is stored; a thin metal film placed on the recording layer and having a structure in which nano-apertures having a size of several nanometers to several hundred nanometers are defined at regular intervals; and a protective layer placed on the thin metal film. As light irradiated from above the protective layer passes through the nano-apertures, physical characteristics of the recording layer are changed, whereby information is stored.

Abstract: An optical recording medium includes an inorganic recording layer, a first protective layer provided on at least one surface of the inorganic recording layer and containing indium oxide, and a second protective layer provided so as to be adjacent to the first protective layer and containing titanium oxide, zirconium oxide, or tin oxide.

Abstract: An object of the invention is to write-once record and reproduce, or only reproduce, a mark smaller than the resolution limit; obtain a high level of reproduction performance (CNR and the like); and realize a high level of reproduction durability. In the invention, between a signal reproducing functional layer composed of Sb or Te and a protecting layer there is introduced a thermally stable diffusion preventing layer, and thereby reactions between the signal reproducing functional layer and the protecting layer due to increased temperature can be prevented or suppressed while increasing reproduction durability.

Abstract: The invention relates to the field of optical information recording. According to the invention, an optical storage structure is proposed comprising a substrate equipped with physical marks whose geometrical configuration defines the recorded information, a superposition of three layers on top of the substrate marks, and a transparent protective layer on top of this superposition, the superposition comprising a layer of indium or gallium antimonide inserted between two ZnS/SiO2 dielectric layers. The antimonide layer has a polycrystalline structure with an average crystal grain size between 5 and 50 nanometers. The non-linear behavior of the superposition of three layers under the read laser makes it possible to read information having a size below the theoretical resolution of the reading system.

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 comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.

Abstract: An information recording medium comprising a substrate having a recording surface provided with emboss pits or guiding grooves, a reflective film formed on the recording surface of the substrate, and a first protective film formed on the reflective film. This information recording medium is featured in that both sides of the information recording medium are constituted by a first surface provided with the protective film and by a second surface formed opposite to the first surface, and that an irradiated light beam is irradiated through the first surface, a recorded information being reproduced based on changes in light intensity of the reflected light beam.