Abstract: The object of this invention is to provide a rewritable phase change type optical recording medium and an optical recording apparatus that are good in erasure characteristics and small in jitter even in high linear velocity high density recording, are unlikely to cause cross erasure even in the use of a substrate with a narrow track width, are unlikely to be deteriorated in signal quality even after repeated irradiation with a laser beam, and are good also in storage durability.

Abstract: A phase change optical recording medium has on a substrate a recording layer consisting essentially of a Sb base thin film and a reactive thin film. The Sb base thin film is formed by depositing a Sb base material containing at least 95 at % of Sb to a thickness of 70-150 Å. The reactive thin film is formed of a material which forms a phase change recording material when mixed with Sb. The reactive thin film is typically formed of an In—Ag—Te or Ge—Te material. Stable write/read characteristics are accomplished at the first overwriting, initializing operation is eliminated, and rewriting is impossible at the same linear velocity as recording.

Abstract: In a method of manufacturing a dielectric layer of ZnS—SiO2 for use in a phase change type optical disk, a target, which is sintered with mixture of ZnS and SiO2, is prepared. The dielectric layer is deposited by the use of a sputtering method in mixed atmosphere of argon gas, oxygen gas, and hydrogen gas. The deposition is carried out such that formation of dangling bonds is suppressed.

Abstract: An optical recording medium of the invention comprises a phase change type recording layer on a surface of a substrate with reading light incident on the recording layer through the substrate, and a dielectric layer provided in contact with the recording layer and on a side of the recording layer on which the reading light is incident. The substrate has a groove acting as a guide groove and a land between adjacent grooves so that the groove and land are used as recording tracks. The phase change type recording layer contains Ag, In, Sb and Te as main components, and has a thickness tR defined by tR≦&lgr;p/20 where &lgr;p is a wavelength of the reading light. The dielectric layer has a thickness td1 that is represented in terms of an optical path length at the wavelength &lgr;p and defined by &lgr;p/2≦td1.

Abstract: In phase change optical recording media wherein initialization process of the recording layer has been the rate determining and cost-increasing factor in the production of the medium, the production cost is reduced by reducing the time required for the initialization and simplification of the initialization process. Stable writing/reading properties are also realized from immediately after the initialization.

Abstract: A phase change optical disc having a substrate and a first dielectric layer formed on the substrate. A recording layer is formed on the first dielectric layer and is convertible into one of an amorphous state and a crystal state according to the power of an incident beam. A second dielectric layer is formed on the recording layer. A reflective layer is formed on the second dielectric layer. The first dielectric layer is formed of a material having a refractive index of 2.7 or more with respect to the incident beam.

Abstract: An optical information recording medium includes a first dielectric protective layer, a recording layer provided on the first dielectric protective layer, including a material represented by a chemical formula of Ag&agr;In&bgr;Sb&ggr;Te&dgr;, wherein &agr;, &bgr;, &ggr; and &dgr; respectively represent an atomic percent of Ag, an atomic percent of In, an atomic percent of Sb, and an atomic percent of Te, and satisfy the conditions of: 1≦&agr;<10, 1<&bgr;≦20, 35≦&ggr;≦70, 20≦&dgr;≦35, &agr;+&bgr;+&ggr;+&dgr;=100, 4&bgr;−&dgr;≦0, &ggr;−2&dgr;≧0, and &ggr;−8&agr;≧0, a second dielectric protective layer provided on the recording layer, and a light reflection and heat dissipation layer provided on the second dielectric protective layer.

Abstract: An optical recording medium structure and its method of manufacture. The optical recording medium structure includes, from bottom to top, a transparent substrate, a first dielectric layer, a first buffer layer, a recording layer, a second buffer layer, a second dielectric layer, an optical compensation layer and a reflection layer. The optical recording medium structure is manufactured by forming the first dielectric layer, the first buffer layer, the recording layer, the second buffer layer, the second dielectric layer, the optical compensation layer and the reflection layer in sequence over the transparent substrate. The first buffer layer and the second buffer layer serves to prevent the diffusion of at least one element from the recording layer into the first and the second dielectric layer and vice versa. The optical compensation layer enhances thermal sensitivity of the recording layer during an optical read/write operation.

Abstract: An optical recording medium with a number of recording layers that is adaptive for enhancing a light efficiency and for improving a responsibility of information and a recording capacity. In the optical recording medium, at least one of recording layers in the number of recording layers are formed of a material having a non-linear optical characteristic. The recording layer made from the non-linear optical characteristic material has a higher reflective coefficient as a light intensity becomes stronger, thereby improving a light efficiency when a recording layer far away from the light source is accessed. Also, the recording layer made from the non-linear optical characteristic allows an effective diameter of a light spot to be reduced, thereby enlarging a recording capacity of the optical recording medium.

Abstract: A rewriteable phase-change optical recording element includes a substrate; and a recording layer over the substrate having at least two sub-layers of different chemical compositions, the compositions and thickness of the sub-layers being selected so that when subject to laser light during a writing process the compositions mixed together to form a high reflectivity mixed crystalline region without using any prior initialization or mixing processes.

Abstract: A phase change optical disk having excellent corrosion resistance, recording signal properties and overwrite cyclability, which contains a first dielectric layer, a recording layer, a second dielectric layer, a reflection layer and a protection layer, characterized in that the reflection layer comprises a first reflection layer made of a metal or an alloy thereof having an electronegativity ranging from 1.9 to 3.0 and a second reflection layer made of Cu, Ag or an alloy thereof, said first reflection layer being in closed contact with the second dielectric layer, and the second reflection layer, with the first reflection layer and the protection layer.

Abstract: A rewritable phase change type optical recording medium having excellent in storage durability such as archival property and overwrite shelf property and is less likely to have increased jitters, lower contrast and bursting due to deterioration by repeated overwriting is disclosed. The optical recording medium comprises a first dielectric layer, a first boundary layer and a recording layer, in tis order, wherein the first boundary layer is in contact with the recording layer. The information in the optical recording medium can be recorded, erased and reproduced by irradiating the recording layer with light. The recording and erasure of information are affected by reversible phase change between amorphous phase and crystalline phase of the recording layer.

Abstract: A recording medium having sufficient characteristics, such as signal characteristics at an elevated density or recording durability, and a method for producing the recording medium. Specifically, there is provided an optical recording medium having a recording layer formed of a phase-change material capable of producing reversible phase changes between the crystal state and the amorphous state, in which the phase changes are induced in the recording layer on illuminating light rays on the recording layer to record and/or erase information signals. The recording layer contains Ag&agr;In&bgr;Sb&ggr;Te&dgr; as the phase-change material, in which the proportions of components &agr;, &bgr;, &ggr; and &dgr; in at% meet the relation of 6≦&agr;≦16, 1.1≦&dgr;/&bgr;≦2.2 and 2≦&ggr;/&dgr;≦3.

Abstract: An information recording medium which includes at least a recording layer, and first and second metallic layers disposed on an opposite side of an energy beam incident side of the recording layer and having different compositions, and in which the first one of the first and second metallic layers located closer to the recording layer contains Al, Ag, Au, Pt and Pd as its main components and a sum of contents of these atoms is 60% or more. Thereby recording and reproducing of information can be realized with a high reliability.

Abstract: An information recording medium which includes at least a recording layer, and first and second metallic layers disposed on an opposite side of an energy beam incident side of the recording layer and having different compositions, and in which the first one of the first and second metallic layers located closer to the recording layer contains Al, Ag, Au, Pt and Pd as its main components and a sum of contents of these atoms is 60% or more. Thereby recording and reproducing of information can be realized with a high reliability.

Abstract: An optical recording medium comprises a recording layer containing, as a photoresponsive material, metal chalcogenide nanoparticles, wherein the metal chalcogenide nanoparticles have an average particle size of 1 to 20 nm and have a surface modified with an adsorbable compound.

Abstract: A multilevel phase change optical recording medium comprises first to N-th (N≧2) phase change optical recording layers, wherein an i-th recording layer and a j-th recording layer, which are two recording layers arbitrarily selected from the first to N-th recording layers, meet the conditions of Ti>Tmi and &tgr;wi<&tgr;xi, and Tj<Tmj or &tgr;wj>&tgr;xj, with respect to a particular recording laser beam selected from recording laser beams having different power levels, where T is the maximum temperature of the recording layer in a recording operation, Tm is the melting point of the recording layer, Tx is the crystallizing temperature of the recording layer, &tgr;w is a time required for the recording layer to be cooled down from Tm to Tx after the laser beam irradiation, and &tgr;x is the crystallizing time of the recording layer.

Abstract: A phase change optical disk having a reflectance relation of Rc<Ra and is adapted such that high recording characteristic can be obtained starting at a first recording time even when a recording operation is carried out without conducting an initialization process. For this purpose, a multiple reflection layer (2), a first dielectric layer (3), a recording layer (4), a second dielectric layer (5), a reflecting layer (6) and an UV curable resin layer (7) are provided on a substrate (1). The recording layer (4) is deposited at a temperature of the substrate during the deposition of the recording layer set to a temperature which makes the recording layer into a stable amorphous conditions and which is lower than a crystallizing temperature of the recording layer. Thus, the recording layer (4) is deposited into a stable amorphous state.

Abstract: An optical recording medium of phase change type wherein favorable recording/reproducing properties are realized in high density recording, in particular, when the minimum mark length is up to 0.6 &mgr;m and the track pitch is up to 0.7 &mgr;m is provided. An optical recording method wherein high transfer rate is realized in the use of such high density recording medium is also provided. The optical recording medium has a recording layer having a thickness dr of 10 to 18 nm, and the first dielectric layer comprises one or more unit dielectric layers and the number of the unit dielectric layers is m (m: an integer of 1 or more).

Abstract: An optical recording medium has a mask layer of a non-linear optical material and a phase change recording layer, and an intermediate dielectric layer disposed therebetween wherein an optical aperture is formed in the mask layer upon exposure to a reading light beam. A recording light beam is irradiated to the recording layer from the side away from the mask layer, and a reading light beam is irradiated to the recording layer from the mask layer side. Microscopic recorded marks below the diffraction limit are readable.

Abstract: An optical information recording medium having a multilayer structure comprising at least a lower protective layer, a phase-change type optical recording layer, an upper protective layer and a reflective layer, on a substrate, wherein the phase-change type optical recording layer has a composition of Zn&ggr;1In&dgr;1Sb&zgr;1Te&ohgr;1, where 0.01≦&ggr;1≦0.1, 0.03≦&dgr;1≦0.08, 0.5≦&zgr;1≦0.7, 0.25≦&ohgr;1≦0.4, and &ggr;1+&dgr;1+&zgr;1+&ohgr;1=1, whereby overwrite recording is carried out by modulation of light intensity of at least strong and weak two levels, so that a crystalline state is an unrecorded state, and an amorphous state is a recorded state.

Abstract: Disclosed is an optical recording layer in which the microaperture for reproducing optical near-field light is controllable so as to read out the optical near-field signals with stability by keeping the signal-reproducing head at a height safe from crashing with the recording medium even when the recording marks are smaller than 100 nm. The optical recording medium is a layered body comprising: (a) a transparent substrate; (b) a first protective layer formed on the substrate; (c) an optically or thermally active layer, which is capable of reversibly generating a micro-aperture by application of light or heat, formed on the first protective layer; (d) a second protective layer, which is under a compressive stress of 200 MPa to 1 GPa, formed on the active layer; (e) an optical recording layer formed on the second protective layer; and (f) a third protective layer formed on the optical recording layer.

Abstract: The present invention provides an optical information medium having excellent weather resistance and repeating characteristics. The optical information medium has a barrier layer between a protective layer and a recording layer. The barrier layer includes GeN or GeON, and at least one element selected from the group consisting of Al, B, Ba, Bi, C, Ca, Ce, Cr, Dy, Eu, Ga, H, In, K, La, Mn, N, Nb, Ni, Pb, Pd, S, Si, Sb, Sn, Ta, Te, Ti, V, W, Yb, Zn and Zr.

Abstract: An information recording medium which is composed of a substrate and a recording layer formed thereon to record information by means of the change in atomic arrangement induced by irradiation with light, said recording layer having at least one interface layer laminated at its interface. It is superior in recording-reproducing-rewriting characteristics and archival life.

Abstract: A phase change optical recording medium which enables optimum direct overwrite even under high speed high density conditions without degrading repetition durability or storage stability of recorded signals. To this end, the phase change optical recording medium has a recording layer formed at least of a phase change material and is recorded and/or reproduced with a laser light beam having a wavelength ranging between 380 nm and 420 nm. A ratio Ac/Aa, where Ac is the absorption rate of said recording layer in a crystalline state and Aa is the absorption rate of said recording layer in an amorphous state, is not less than 0.9, and a crystallization promoting layer promoting the crystallization of the phase change material is contacted with at least one surface of the recording layer.

Abstract: Noise of the read-out signal is reduced in an optical information medium comprising a supporting substrate and a reflective layer disposed on the supporting substrate wherein the reading beam irradiates the medium from the side where the reflective layer is formed. In addition, noise of the read-out signal is reduced without adversely affecting the recording properties in an optical information medium comprising a supporting substrate, and a reflective layer and a recording layer disposed on the supporting substrate in this order wherein the recording beam irradiates the medium from the side where the reflective layer is formed. In the medium, the reflective layer has a crystallite size of up to 30 nm.

Abstract: The optical recording medium (20) has a substrate (1) and a stack (2) of layers provided thereon. A phase change recording layer (5), having a melting point Tmp is sandwiched between a first (3) and a second (7) dielectric layer. A crystallization-accelerating layer (4, 6) is being interposed in contact with the recording layer (5). Further a reflective layer (8) is present and an optional cover layer (9).

Abstract: In a material for a heat-resistant protection layer and constituting one of the components of a phase variation type recording medium, at least one compound having a thermal conductivity of higher than 10 W/m.deg inclusive in a bulk state is contained. This kind of material realizes a phase variation type optical data recording medium having a high erasure ratio and allowing data to be repeatedly recorded and erased a number of times by small power even at the time of high-speed recording and erasure.

Abstract: Phase-change type rewritable optical recording media, such as optical discs, optical cards, and optical tapes, where recorded data can be erased or overwritten and where data can be recorded with high speed and high density by applying a light beam can include an optical recording medium is one that includes a laminate member, which in various embodiments contains a transparent substrate, a first dielectric layer, a recording layer, a second dielectric layer, a light absorbing layer, and/or a reflecting layer. In various embodiments of the invention, the shortest distance between recorded marks in the recording direction along the track is less than &lgr;/NA, with &lgr; and NA denoting the wavelength of the light used and the numerical aperture of the objective lens of the optical head, respectively.

Abstract: In a phase change optical recording medium, by determining heat conductivity relatively higher in one of interference layers on and under the recording layer, heat absorbed into the recording layer can be released moderately through an interference layer. Thereby, cross erasure caused by heating of adjacent tracks can be prevented, and at the same time, excessive heat radiation is prevented from a part of the recording layer nearer to the substrate to thereby maintain appropriate heat in the recording layer. As a result, cross-erasure is prevented, and data can be rewritten with the supply of typical recording/erasure power.

Abstract: An optical information recording medium having a multilayer structure comprising at least a lower protective layer, a phase-change type optical recording layer, an upper protective layer and a reflective layer, on a substrate, wherein the phase-change type optical recording layer has a composition of Gef(SbdTe1−d)1−f, where 0.65≦d≦0.85, and 0.01≦f≦0.20, whereby overwrite recording is carried out by modulation of light intensity of at least strong and weak two levels, so that a crystalline state is an unrecorded state, and an amorphous state is a recorded state.

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: A phase change optical disk medium includes a disklike substrate, and a recording layer formed by a laminate of a plurality of thin layers including a phase change layer. Information marks are recorded on the phase change layer by phase changes from a crystal phase to an amorphous phase and vice versa. The recording layer has tracks for recording information marks formed by groove portions and land portions respectively taking alternate concave and convex shapes. The track has an interval in range of 0.54 to 0.64 &mgr;m and the recording layer has a ratio of the optical reflectance of 0.35 or less when the phase change layer has changed to the amorphous phase in case where the optical reflectance of the recording layer is 1 when the phase change layer is in the crystal phase.

Abstract: Phase-change type, reversible optical information recording medium, being possible for recording, reproducing, erasing, and rewriting of information, by use of a laser beam. This invention consists of recording thin film of ternary elements, for example, containing Ge, Te, Sb/or Bi or quaternary elements containing the fourth element of Se with which a part of Te is replaced, which is established on such surface—flat substrates as glass or plastics. In this case, the component ratio of Te and Se is selected not to be excess for other elements, such as Ge, Sb/or Bi so as to be fixed as stable compounds of stoichiometric compositions of GeTe, Sb2Te3/or Bi2Te3, or GeSe, Sb2Se3/Bi2Se3 when crystallized. Strictly speaking, a concentration of each component is selected to have proper ratio of the number of atomes each other so as to represent whole composition as the sum of each component. By this treatment, it is possible to have high crystallization speed and long cyclability of recording/erasing.

Abstract: An information recording medium includes a substrate, a first protective layer formed on the substrate, a recording layer formed on the first protective layer, and a second protective layer formed on the recording layer. The first protective layer has a thickness in a range from 65 nm to 130 nm. The second protective layer has a thickness in a range from 15 nm to 45 nm. The recording layer has a thickness in a range from 15 nm to 35 nm and is composed of a phase-change alloy with the composition in terms of atomic percentage being represented by the formula AgaInbSbcTed where 0<a<6, 3≦b≦15, 50≦c≦65, 20≦d≦35, a+b+c+d=100. The information recording medium is configured to provide capabilities of reading, writing and overwriting of information at linear rotation rates ranging from 1.2 m/s to 11.2 m/s.

Abstract: The optical recording medium of this invention includes: a first substrate having a first information surface; a semitransparent reflection film formed on the first information surface of the first substrate; a second substrate having a second information surface; a reflection film formed on the second information surface of the second substrate; and an adhesive layer for adhering the first substrate and the second substrate so that the first information surface and the second information surface face each other, wherein the thickness of the first substrate is 0.56 mm or more, the thickness of the adhesive layer is 30 &mgr;m or more, and the total thickness of the first substrate and the adhesive layer is 0.68 mm or less.

Abstract: A layer arrangement for an optical component or an optical data storage element such as a CD, a DVD, a hybrid disk or a super audio disk, has at least one layer which is at least predominantly Si(1-x)Ge(x)Hy as a spectrally selective layer for a predominant reflection of light in a lower part of a spectral range of 600 nm to 800 nm and for a predominant transmission of light in an upper part of said spectral range. The values for x and y are 0.1<x≦0.9 and 0≦y≦0.5.

Abstract: An optical information recording medium of the present invention includes a transparent substrate and a multi-layered film formed on the transparent substrate. The multi-layered film includes a lower protective layer, a recording layer that changes reversibly between different states detectable optically by irradiation of light beams, an upper protective layer, an intermediate layer and a reflective layer in this order from the side near the transparent substrate. Of the upper protective layer, the intermediate layer and the reflective layer, the heat conductivity of the layer closest to the recording layer is the smallest of the three layers, and thereafter the heat conductivities of the others increase with increasing the distance from the recording layer, and the thickness of the recording layer is from 4 nm to 16 nm. In addition, a light absorption layer can be used in place of the intermediate layer.

Abstract: Phase-change type, reversible optical information recording medium, being possible for recording, reproducing, erasing, and rewriting of information, by use of a laser beam. This invention, consists of recording thin film of ternary elements, for example, containing Ge, Te, Sb/or Bi or quaternary elements containing the fourth element of Se with which a part of Te is replaced, which is established on such surface—flat substrates as glass or plastics. In this case, the component ratio of Te and Se is selected not to be excess for other elements, such as Ge, Sb/or Bi so as to be fixed as stable compounds of stoichiometric compositions of GeTe, Sb2Te3/or Bi2Te3, or GeSe, Sb2Se3/Bi2Se3 when crystallized. Strictly speaking, a concentration of each component is selected to have proper ratio of the number of atoms each other so as to represent whole composition as the sum of each component. By this treatment, it is possible to have high crystallization speed and long cyclability of recording/erasing.

Abstract: A magnetic recording medium comprising first, second and third magnetic layers laminated in succession, wherein when (1) the magnetic wall energy density, saturation magnetization, magnetic wall coercivity and film thickness of the first magnetic layer at a temperature T represented by cgs unit system are defined as &sgr;1, Ms1, Hw1 (2) h1, respectively, and the magnetic wall energy density, saturation magnetization, magnetic wall coercivity and film thickness of the third magnetic layer are defined as &sgr;3, Ms3, Hw3 and h3, respectively, (3) the interface magnetic wall energy density between the first magnetic layer and the third magnetic layer is defined as &sgr;w13, and (4) the lowest temperature at which &sgr;w13 is 0 erg/cm2 is Ts, at least 2Ms1*Hw1<&sgr;w13/h1  and 2Ms3*Hw3>&sgr;w13/h3  are satisfied, at room temperature and when a suitable temperature Tp is chosen, within a temperature range greater than the temperature Ts and lower by 10° C.

Abstract: An optical information recording medium comprising a thin plastic substrate of 0.6 mm or thinner, wherein the substrate is protected against strain without being limited by a film structure and a film formation condition. A single-layer or multilayer thin film (70) is formed on a plastic disk-like substrate having a center hole (10). This thin film (70) has a strain relief area (72) inside a recording area (71). This strain relief area (72) is formed by setting an outer diameter of an undeposited inner portion (5) to a value satisfying the following formula (1), for example: A0≦AX≦−0.172P+0.163 where A0: diameter of center hole, AX: outer diameter of undeposited inner portion, P: total strain occurring in thin film when film depositing.

Abstract: A rewritable optical information medium includes a substrate coated with two carbide layers, a phase-change recording layer between two carbide layers, and a light-absorptive layer of a material like Si, Ge, Mo, or W to slow the cooling when scanned with laser light so that the medium can be used for high data rate recording. The material is capable of a user data bit rate of 50 Mbit/s.

Abstract: An optical recording medium comprising, in the following order, a substrate, a reflecting layer, a lower dielectric layer, an optical recording layer, the optical recording layer recording information by means of change in a physical property of the optical recording layer which is generated by an applied light beam, the change in a physical property of the optical recording layer being conducted at an operating temperature, and an upper dielectric layer, wherein the substrate has a thermal deformation temperature lower than the operating temperature and the optical recording medium further comprises a thermally insulating layer between the substrate and the reflecting layer.

Abstract: The present invention relates to an optical recording medium having a protective layer and a phase-change recording layer on a substrate, said protective layer containing a metallic oxysulfide and an optical recording medium having a protective layer and a phase-change recording layer, said protective layer being formed by sputtering using a target comprising a metallic oxysulfide.

Abstract: The present invention provides an optical disc capable of effectively reducing a reproduction signal jitter value and obtaining a wider record power margin assuring a reproduction limit jitter value to obtain a preferable recording/reproduction characteristic even after a number of times of recording repeated. The optical disc includes the following films successively formed on a substrate 2: a first dielectric film 3; a phase change recording film 4 whose phase is changed between a crystalline state and an amorphous state thereby to record an information signal; a second dielectric film 5; and a light reflection film formed on the phase change recording film 4 and constituted by an Al alloy containing Cu in a range from 0.1 to 1.0 atomic %.

Abstract: A phase change optical recording medium has on a substrate a recording layer consisting essentially of a Sb base thin film and a reactive thin film. The Sb base thin film is formed by depositing a Sb base material containing at least 95 at % of Sb to a thickness of 70-150 Å. The reactive thin film is formed of a material which forms a phase change recording material when mixed with Sb. The reactive thin film is typically formed of an In—Ag—Te or Ge—Te material. Stable write/read characteristics are accomplished at the first overwriting, initializing operation is eliminated, and rewriting is impossible at the same linear velocity as recording.

Abstract: A phase change recording medium comprises a substrate, an interference layer formed on the substrate and a recording layer formed on the interference layer. In this, the reflectance of the crystalline region in the recording layer is lower than that of amorphous region therein, and the interference layer comprises at least three layers of which the dielectric constant differs from that of the adjacent layers. With that constitution, the optical characteristics and the thermal characteristics of the medium are all optimized.

Abstract: An information storage medium includes a substrate, a thin film formed on the substrate and having a reflectance changed by a phase change caused by irradiation of an energy beam irradiated via the substrate and a first reflective layer and a second reflective layer on the film directly or via an intermediate layer. The thin film includes one of In3SbTe2, In35Sb32Te33, In31Sb26Te43 and Ag—In—Sb—Te. The first reflective layer and the second reflective layer are piled up in the recited order from a thin film side with the first reflective layer consisting of a material having an attenuation factor k of 2 or less and selected from a group of silicon based materials and the second reflective layer consisting of a material having an attenuation factor k of at least 3.

Abstract: The object is to hold the recording, reproduction and rewrite characteristics better than in the prior art. An information recording medium comprises an information recording thin film as a recording layer formed on a substrate for recording and/or reproducing information by the change in the atomic arrangement caused by the radiation of light. The medium further comprises at least one protective layer. The protective layer and the recording layer are formed in that order from the light incidence side, followed by forming at least one absorption control layer, thereby exhibiting a superior rewrite characteristic.

Abstract: A recording medium includes a transparent substrate; a crystalline phase-change layer provided over the transparent substrate; a dielectric layer provided over the phase-change layer; a metallic reflector layer provided over the dielectric layer; and the crystalline phase-change layer having a thickness and phase-change material selected so that data can be recorded in it on a first write, but on second or subsequent writes the written data results in at least a 50% increase in data jitter.