Abstract: To provide an optically transparent film containing 0.01 to 20% by weight glass forming oxide consisting of Nb2O5, V2O5, B2O3, SiO2, and P2O6; 0.01 to 20% by weight Al2O3 or Ga2O3; and 0.01 to 5% by weight hard oxide of ZrO2 and TiO2 as required; balance being ZnO, and a sputtering target for forming such a film. This sputtering target reduces occurrence of particles during sputtering, decreases the number of interruption or discontinuance of sputtering to improve production efficiency, and forms a protective film for optical disks with large transmittance and low reflectance.

Abstract: A multi-layered optical disc having its recording unit comprised of plural information recording layers, in which two or more information recording layers are layered on a substrate 0.3 to 1.2 mm in thickness, with the interposition of a transparent layer, to from a recording unit, a light transmitting protective layer is formed on the recording unit to a thickness of 10 to 177 &mgr;m, and in which the light is illuminated from the side of the light transmitting protective layer to effect recording and/or reproduction of information signals. At least one of the information recording layers except the information recording layer formed at a remotest position from the light transmitting protective layer has a phase change material as a recording material.

Abstract: A phase change optical recording medium is provided wherein the power of the laser beam per unit area required in the initialization is reduced.

Abstract: The present invention provides an optical information recording medium having excellent characteristics in repetitive recording and a sufficient C/N ratio. The optical information recording medium includes a recording layer containing Ge, Te and Sb and a diffusion preventing layers in contact with the recording layer. A composition ratio of Ge, Te and Sb in the recording layer has numerical values which lie within the range represented by the area ABCDE in a ternary phase diagram of Ge, Te and Sb, where the points A, B, C, D and E are as follows: A (Ge50Te50), B (Ge22.5Sb22.0Te55.5), C (Ge17.0Sb41.5Te41.5), D (Ge48.0Sb26.0Te26.0), E (Ge65Te35) The diffusion layer contains at least one compound selected from an oxide, a nitride, a nitrogen oxide, a carbide and a fluoride.

Abstract: A sputtering target for fabricating a recording layer of a phase-change type optical recording medium contains a compound or mixture including as constituent. elements Ag, In, Te and Ob with the respective atomic percent (atom. %) of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 2≦&agr;≦30, 3≦&bgr;≦30, 10≦&ggr;≦50, 15≦&dgr;≦83 and &agr;+&bgr;+&ggr;+&dgr;=100, and a method of producing the above sputtering target is provided. A phase-change type optical recording medium includes a recording layer containing as constituent elements Ag, In, To and Sb with the respective atomic percent of &agr;, &bgr;, &ggr; and &dgr; thereof being in the relationship of 0<&agr;≦30, 0<&bgr;≦30, 10≦&ggr;≦50, 10≦&dgr;≦80, and &agr;+&bgr;+&ggr;+&dgr;=100, and is capable of recording and erasing information by utilizing the phase changes of a recording material in the recording layer.

Abstract: A phase-change optical recording medium capable of implementing record and readout operations of information data through reversible phase transition between amorphous and crystalline states induced by light beam irradiation in a recording layer included in the recording medium, including at least a transparent substrate and contiguous layers formed on the substrate in order as follows, a lower dielectric protective layer, the recording layer, an upper dielectric protective layer, and a reflective/heat dissipating layer, in which the upper dielectric protective layer essentially consists of a mixture of ZrO2 and SiO2, having a composition of (ZrO2)100−x (SiO2)x, where 0<x<60 (mole %).

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 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 WORM optical recording element includes a substrate; an amorphous phase-change recording layer disposed over the substrate; a dielectric layer disposed adjacent to the amorphous phase-change layer; a reflector layer disposed adjacent to the dielectric layer; and wherein the material and the thickness of the layers are selected such that recording can be performed on the optical recording element by using a focused laser beam to form crystalline marks in the phase-change layer using laser pulses with less than 40 nS in duration, the reflectivity of the amorphous phase as measured by a collimated beam is higher than 28% and the contrast of the read-back signal is higher than 0.6, and the second and subsequent writing over previous recording results in at least a 50% increase in read out jitter.

Abstract: A phase-change optical information recording medium including a substrate and a recording layer provided on the substrate, the recording layer including a phase-change recording material capable of recording information, reproducing recorded information, and erasing recorded information reversibly with reversible phase changes in the phase-change recording material, with successive formation of a recording mark with a low reflectivity and a length of at least one unit extending in an optical recording scanning direction, and a space with a high reflectivity and a length of at least one unit extending in the optical recording scanning direction, wherein information is recorded by a plurality of signals being recorded in the recording layer, each signal constituting a recording mark area including a recording initiation marking portion with (a) a length of at least two times a minimum length of the recording mark and (b) a width (W1) of at least 1.

Abstract: An optical information recording medium includes a substrate for allowing laser light to be transmitted therethrough; a first protective layer for protecting the substrate: a recording layer for allowing information to be recorded thereon by laser light irradiation; a second protective layer for protecting the recording layer: an absorption layer for absorbing heat generated by the laser light, and a reflective layer for reflecting the laser light.

Abstract: An optical information recording medium having a substrate, a first dielectric layer provided on the substrate, a recording layer provided on the first dielectric layer, a second dielectric layer provided on the recording layer, a light reflection and heat dissipation layer provided on the light reflection and heat dissipation layer, and a crystallization accelerating layer provided in contact with at least a portion of the recording layer and made of a material including a substance selected from Bi, Bi-containing compounds, Al, Al-containing compounds, In, In-containing compounds, Tl and Tl-containing compounds.

Abstract: An optical recording medium having a recording layer which comprises an Sb—Te alloy containing excess amount of Sb over the vicinity of Sb70Te30 eutectic composition and shows reversible phase changes on light beam irradiation between a crystalline state and an amorphous state differing from each other in optical properties, a method of writing and erasing information using the same, and a process of producing the same are described.

Abstract: A phase-change recording medium with Sb3Te compounds which are formed by initialization-less process steps is provided through the formation of recording media having layered structure including suitably selected materials together with methods for fabricating such recording media, thereby leading to DVD-ROM compatible recording media capable of achieving recording density of 2.6 GB or more on a disc of 120 mm in diameter. The recording medium includes an Sb3Te recording layer and a crystallization accelerating layer formed contiguously with the recording layer. The crystallization accelerating layer is formed to suitably include impurities as record stabilization agents. At least one additional impurity layer may be formed contiguous to said recording and/or crystallization accelerating layer.

Abstract: High temperature reliability, and in particular, the high temperature reliability after repeated overwriting operations is improved in an optical recording medium wherein a material of Ag—In—Sb—Te system is used for the recording layer. Provided is an optical recording medium having a recording layer of phase change type, wherein said recording layer contains Ag, In, Sb, and Te as its main components, and Ge as its sub-component such that, when molar ratio of the elements constituting the main and sub-components is represented by formula (I): (AgaInbSbcTed) (1-e/100)Gee, 2≦a≦20, 2≦b≦20, 35≦c≦80, 8≦d≦40, a+b+c+d=100, and 1≦e≦15.

Abstract: The optical recording medium of the present invention has a phase change recording layer. This recording layer contains at least two elements selected from Sb, Te, Ge, and In as main elements, and at least one element selected from rare earth elements (Y, Sc, and lanthanoid), Zr, Hf, Ti and Sn as an auxiliary element, and also, a eutectic mixture can exist in the recording layer. The optical recording medium of the present invention can be operated at a high transfer rate, and has a high storage reliability.

Abstract: In an optical recording medium wherein a layer of nonlinear optical material and a recording layer of phase change type are formed extreme close to each other to enable reading of small record marks beyond diffraction limit, a high C/N is realized and decrease of the C/N in the reading is also suppressed. More illustratively, the optical recording medium has a mask layer (nonlinear optical material layer) and a recording layer of phase change type formed to sandwich an intermediate dielectric layer such that an optical aperture can be formed in the mask layer by irradiation of reading light beam from the side of the mask layer. The intermediate dielectric layer has a thickness of 5 to 70 nm; or near field light generated near the optical aperture is used in the reading. The recording layer contains Ag, In, Sb and Te as its main components and Ge and/or N as its sub-component.

Abstract: An information recording medium having a substrate, a lower superficial layer formed on the substrate and having a thickness of not more than 25 nm, and a recording layer formed on the lower superficial layer. Information is recorded on the recording layer in accordance with a change of atomic arrangement caused by irradiation of light. The information recording medium includes and an absorption control layer formed on the recording layer.

Abstract: An optical recording medium having stable recording and reproducing characteristics even after a long term storage and a method of manufacturing the same are provided. The optical recording medium includes a substrate and a recording layer positioned above the substrate. The recording layer includes a phase change layer changing in phase reversibly between a crystalline state and an amorphous state by an irradiation of an optical beam, and a crystalline nucleation layer positioned adjacent to the phase change layer for facilitating crystallization of the phase change layer. The phase change layer is in the amorphous state, and the crystalline nucleation layer contains Te in a range between 33 atom % and 67 atom %.

Abstract: A phase-change optical information recording medium capable of recording information therein, reproducing recorded information therefrom, rewriting recorded information, and erasing recorded information therefrom, which phase-change optical information recording medium is provided with a recording layer containing therein a phase-change recording material including Ge, Ga, Sb, Te, and one element selected from the group consisting of Mg and Ca, which recording material is capable of performing a reversible phase transition from a noncrystalline phase to a crystalline phase and vice verse with the application of an electromagnetic wave thereto.

Abstract: An information recording medium includes at least a recording layer formed on a substrate, the recording layer including a phase change layer in which a reversible phase change is caused between a crystalline state and an amorphous state by irradiation of a light beam, and a crystallization-ability improving layer for improving a crystallization ability of the phase change layer. The crystallization-ability improving layer is formed before the phase change layer is formed. Thus, crystal nucleus generation and crystal growth are caused during formation of the phase change layer, so that at least a portion of the phase change layer is in the crystalline phase after the formation. Thus, information signals can be recorded/reproduced at a high density and a high linear velocity, and thus the present invention provides a highly reliable optical information recording medium.

Abstract: The present invention discloses a rewritable phase-change optical disk having a recording material of a five-element alloy, Te—(Ge,Bi,Sb)—X, wherein X is B (boron) or C (carbon); Te (tellurium) ranges from 47 to 60 atomic percentage (at. %); Ge (germanium) ranges from 12 to 48 at. %; and Si (silicon) together with Sb (antimony) range from 5 to 41 at. %, based on the total atomic number of Te, Ge, Bi and Sb; and B or C range from 0.05 to 4 at. %, based on the total atomic number of Te, Ge, Bi, Sb and X.

Abstract: A multi-rewritable optical recording medium includes a surface plasmon super-resolution layer. The surface plasmon super-resolution layer is a three-layer structure including a first dielectric layer, a second dielectric layer, and a metal layer sandwiched between said first dielectric layer and said second dielectric layer. The metal layer with a certain thickness performs the surface plasmon effect when a laser beam with a suitable wavelength irradiates thereon. By the design and arrangement of the surface plasmon super-resolution layer, the small size of information-carrying pits and the recording marks in the range of around 100 nm is accessible. As a result, the super-resolution without the limit of the optical diffraction is achieved.

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 information recording medium having recording, reproducing, and rewriting characteristics better than those of prior art media. The media has a recording layer made of a material represented by the following formula: Gex−wSbyTezMw, wherein 0.13≦x≦0.22, 0.20≦y≦0.32, 0.53≦z≦0.60, 0≦w≦0.06, x+y+z=1, and M is any one of Na, Mg, Al, P, S, Cl, L, Ca, Sc, Zn, Ga, As, Se, Br, Rb, Sr, Y, Zr, Nb, Ru, Rh, Cd, In, Sn, I, Cs, Ba, La, Hf, Ta, Re, Os, Ir, Hg, Tl, Pb, Th, U, Ag, Cr, W, Mo, Pt, Co, Ni, Pd, Si, Au, Cu, V, Mn, Fe, Ti and Bi.

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: 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: 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 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: 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: 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: A protective layer is applied to the surface of a compact disc precursor that must be protected from dust during manufacture. The layer is removable and preferably made of ethylene vinyl acetate.

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 recording layer comprising a dye layer containing a trimethine-based cyanine dye having nitro group attached to a benzene ring or to a naphthalene ring, both being bonded to indole ring, is capable of minimizing the second peak in relative to the main peak shown in FIG. 1, thus enabling the spectrum consisting of a main peak and a second peak to become sharp. The recording layer is capable of performing the recording and reading with a laser beam having a wavelength falling within a range of 620 nm to 690 nm.

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.