JP2013077350A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical recording medium in which a power margin during high-speed recording can be improved.SOLUTION: The optical recording medium includes at least: a substrate having a guide groove formed therein; and on the substrate in the following order, a reflection layer having a light-reflecting function; a recording layer containing as a main component a dye that has a light-absorbing function at a wavelength of recording and reproducing light in an unrecorded state; an interface layer in contact with the recording layer; and a cover layer where recording and reproducing light for the recording layer enters. The interface layer contains (InO-SnO) and/or (InO-ZnO) as a main component M, and further contains at least one material selected from a sub-component group (A) consisting of NbO, TaO, TiO, YOand LaF.

Description

  The present invention relates to an optical recording medium, and more particularly to an optical recording medium having a recording layer containing a dye.

  In recent years, blue lasers capable of ultra-high density recording have been rapidly developed, and write-once type optical recording media corresponding thereto have been developed. In particular, development of a dye-coated write-once medium that enables efficient production at a relatively low cost is strongly desired.

  For example, an extremely high-density dye-coated write-once optical recording medium having good recording / reproduction characteristics using a substrate having a relatively shallow groove depth that can be stably formed has been proposed (Patent Documents 1 and 2). . That is, a substrate having guide grooves formed thereon, a layer having a light reflection function on the substrate, a recording layer containing as a main component a dye having a light absorption function with respect to the recording / reproducing light wavelength in an unrecorded state, And a cover layer on which the recording / reproducing light is incident on the recording layer in this order, and a guide groove on the side far from the surface on which the recording / reproducing light beam obtained by focusing the recording / reproducing light is incident on the cover layer In this case, the optical recording medium is configured such that the reflected light intensity of the recording pit portion formed in the recording groove portion is larger than the reflected light intensity in the recording groove portion when not recorded, mainly due to a phase change.

Here, the Patent Document 1, between the recording layer and the cover layer, it is proposed to use a ZnS-SiO ₂ or the like as the interface layer. Further, in Patent Document 2, it is intended to obtain good recording characteristics by promoting or suppressing deformation of the recording layer, in particular, bulging deformation toward the cover layer, and between the recording layer and the cover layer. It is proposed to use ITO (In ₂ O ₃ —SnO ₂ ) as the interface layer. It is disclosed that the ITO interface layer exhibits better recording / reproduction characteristics than the ZnS-SiO ₂ interface layer. Conventionally, ITO (In ₂ O ₃ —SnO ₂ ) having a weight ratio of In ₂ O ₃ —SnO ₂ of 90:10 wt% has been used.

JP 2005-228402 A JP 2009-026378 A

However, it has become clear that these conventional optical recording media have the following problems. The write once optical recording medium is required to be able to record at a higher speed in order to shorten the recording time. However, in the case of ITO (In ₂ O ₃ —SnO ₂ (90:10 wt%)) that has been used conventionally, When the recording speed increases, the power margin becomes narrower than that during low-speed recording, and it becomes difficult to ensure recording / reproduction stability.

  The present invention has been made in view of the above problems, and an object thereof is to provide an optical recording medium capable of improving a power margin at the time of high-speed recording.

That is, the gist of the present invention is at least a substrate on which guide grooves are formed, a reflective layer having a light reflecting function on the substrate, and a dye having a light absorbing function with respect to a recording / reproducing light wavelength in an unrecorded state. In an optical recording medium comprising a recording layer contained as a main component, an interface layer in contact with the recording layer, and a cover layer on which recording / reproducing light is incident on the recording layer, the interface layer comprises (In ₂ O ₃ —SnO ₂ ) and / or (In ₂ O ₃ —ZnO) as a main component M and further comprising Nb ₂ O ₅ , Ta ₂ O ₅ , TiO ₂ , Y ₂ O ₃ , and LaF. The optical recording medium comprises at least one material selected from the subcomponent group A.

  At this time, when the number of moles of constituent molecules of the main component M in the interface layer is Ma and the number of moles of constituent molecules of the subcomponent group A is Aa, Aa / (Ma + Aa) is 0.02 to 0.50. Preferably there is.

  In the interface layer, Aa / (Ma + Aa) is 0.04 to 0.20, where Ma is the number of moles of constituent molecules of the main component M and Aa is the number of moles of constituent molecules of the subcomponent group A. It is preferable.

Furthermore, it is preferable that the interface layer contains Nb ₂ O ₅ .

  According to the present invention, an optical recording medium having a sufficient power margin during high-speed recording can be obtained.

1 is a schematic cross-sectional view illustrating a configuration of a first embodiment of an optical recording medium according to the present invention. It is a typical sectional view explaining composition of a 2nd embodiment of an optical recording medium concerning the present invention.

  Hereinafter, embodiments of the present invention will be described in detail assuming a write-once Blu-ray disc which is a large-capacity optical recording medium. However, the present invention is not limited to the following embodiments, and The present invention can be arbitrarily modified and implemented without departing from the scope of the invention.

[1. First Embodiment]
FIG. 1 is a diagram for explaining the configuration of the first embodiment of the optical recording medium of the present invention. The first embodiment will be described using a “film surface incident configuration” write-once medium having a recording layer mainly composed of a dye.

  In the optical recording medium 20 according to the first embodiment, at least a reflection layer 23 having a light reflection function on a substrate 21 on which a guide groove is formed, and light with respect to a recording / reproducing light wavelength in an unrecorded (before recording) state. It has a structure in which a recording layer 22 having a light absorption function, containing a dye having an absorption function as a main component, and an interface layer 30 and a cover layer 24 in contact with the recording layer 22 are sequentially laminated. The optical recording medium 20 according to the first embodiment has a film surface incident configuration (also referred to as reverse stack), and a recording / reproducing light beam 27 condensed from the cover layer 24 side through the objective lens 28 is recorded / reproduced. Perform by entering.

  Hereinafter, the reflective layer having the light reflecting function is simply referred to as “reflective layer 23”, and the recording layer 22 having the light absorbing function mainly composed of the dye is simply referred to as “recording layer 22”. When the recording / reproducing light beam 27 is incident on the cover layer 24 side of the film surface incident configuration, a high NA (numerical aperture) of about NA (numerical aperture) = 0.6 to 0.9 is usually used for high-density recording. Objective lens 28 is used. As the recording / reproducing light wavelength λ, a red to blue-violet wavelength (about 350 nm to 600 nm) is often used. Furthermore, for high-density recording, it is preferable to use a wavelength range of 350 nm to 450 nm, but the present invention is not necessarily limited thereto.

  In this embodiment, in FIG. 1, the guide groove portion on the side far from the incident surface of the recording / reproducing light beam 27 on the cover layer 24 (the surface 29 on which the recording / reproducing light beam is incident) is defined as a recording groove portion. Recording is performed such that the reflected light intensity of the formed recording pit part is higher than the reflected light intensity of the recording groove part when not recorded (hereinafter referred to as LtoH recording). The main mechanism is that the increase in reflected light intensity is mainly due to the phase change of the reflected light at the recording pit portion. That is, the change before and after recording of the reciprocating optical path length of reflected light in the recording groove is mainly used.

  Here, in the film surface incident type optical recording medium 20, the guide groove portion (coincidence with the groove portion of the substrate 21) far from the incident surface (the surface 29 on which the recording / reproducing light beam is incident) of the recording / reproducing light beam 27 on the cover layer 24. Is called the cover layer groove portion 26 (in-groove), and the guide groove portion close to the surface 29 on which the recording / reproducing light beam is incident (matched with the groove portion of the substrate 21) is called the cover layer groove portion 26 (on-groove). I will decide.

  Here, by controlling the optical characteristics such as the groove shape and the refractive index of each layer, LtoH recording is realized by using the cover layer groove portion 25 (in-groove) as a recording track (hereinafter referred to as in-groove recording). It becomes possible to do.

<Specific Layer Configuration and Preferred Mode of Material>
In the following, regarding the specific materials and aspects of the layer configuration shown in FIG. 1, considering the situation where the development of the blue wavelength laser is advanced, the case where the wavelength λ of the recording / reproducing light beam 27 is around 405 nm is assumed. I will explain.

(Substrate 21)
When the substrate 21 is used in a film surface incident configuration, plastic, metal, glass or the like having appropriate processability and rigidity can be used. Unlike the conventional substrate incidence configuration (configuration in which the recording / reproducing light beam is incident from the substrate side), there are no restrictions on transparency and birefringence. The guide groove is formed on the surface. However, in the case of metal or glass, it is necessary to provide a light or thermosetting thin resin layer on the surface and to form the groove there. In this respect, it is preferable from the viewpoint of manufacturing that a plastic material is used and a substrate shape (particularly, a disk shape) and a guide groove on the surface are formed at once by injection molding.

  As the plastic material that can be injection-molded, polycarbonate resin, polyolefin resin, acrylic resin, epoxy resin, and the like conventionally used in CDs and DVDs can be used. The thickness of the substrate 21 is preferably about 0.5 mm to 1.2 mm. In particular, the thickness of the optical recording medium 20 is preferably 1.2 mm, which is the same as that of a conventional CD or DVD. This is because the case used in conventional CDs and DVDs can be used as it is, and it is also preferable for compatibility of the recording / reproducing apparatus. According to the Blu-ray Disc format standard, the Blu-ray disc defines that the thickness of the substrate 21 is 1.1 mm and the thickness of the cover layer 24 is 0.1 mm.

  A tracking guide groove is formed in the substrate 21. In the first embodiment, the track pitch at which the cover layer groove portion 25 becomes the recording groove portion is preferably 0.1 μm or more, more preferably 0.2 μm, in order to achieve higher density than CD-R and DVD-R. It is preferably 0.6 μm or less, and more preferably 0.4 μm or less. The groove depth is preferably in a range of approximately 20 nm to 60 nm. Within the above range, the groove depth is appropriately optimized in consideration of the recording groove portion reflectance in an unrecorded state, the signal characteristics of the recording signal, the push-pull signal characteristics, the optical characteristics of the recording layer 22, and the like.

  In the present embodiment, since the interference due to the phase difference of the reflected light mainly at the recording groove portion and between the recording groove portions is utilized, it is preferable that both exist in the focused light spot. For this reason, it is preferable that the recording groove width (width of the cover layer groove portion 25) is smaller than the spot diameter (diameter in the groove transverse direction) of the recording / reproducing light beam 27 on the recording layer surface. In an optical system with a recording / reproducing light wavelength λ = 405 nm and NA (numerical aperture) = 0.85, when the track pitch is 0.32 μm, the recording groove width should be in the range of 0.1 μm to 0.2 μm. preferable. Outside these ranges, it is often difficult to form grooves or inter-groove portions.

  The guide groove is usually added by groove modulation, groove modulation such as groove meandering, groove depth modulation, or irregular pits due to intermittent or intermittent recording grooves, in order to give additional information such as addresses and synchronization signals. Have a signal. For example, in a Blu-ray disc, a wobble address method using two modulation methods, MSK (minimum-shift-keying) and STW (saw-tooth-wobbles), is used.

(Reflection layer 23)
The reflective layer 23 having a light reflecting function preferably has a high reflectance with respect to the wavelength of the recording / reproducing light beam 27 and a reflectance of 70% or more with respect to the wavelength of the recording / reproducing light beam 27. Examples of visible light used as the wavelength of the recording / reproducing light beam 27, particularly those exhibiting high reflectivity in the blue wavelength region, include Au, Ag, Al, and alloys containing these as main components. More preferably, it is an alloy mainly composed of Ag having a high reflectance at a wavelength λ = 405 nm and a small absorption. Mainly composed of Ag, Au, Cu, rare earth elements (particularly Nd), Nb, Ta, V, Mo, Mn, Mg, Cr, Bi, Al, Si, Ge, etc. 0.01 atomic% or more and 10 atomic% Addition of the following is preferable because corrosion resistance against moisture, oxygen, sulfur and the like can be improved. In addition, a dielectric mirror in which a plurality of dielectric layers are stacked can be used.

  The film thickness of the reflective layer 23 is preferably 70 nm or less, and more preferably 65 nm or less in order to maintain the groove step on the surface of the substrate 21. Except for the case where a two-layer medium described later is formed (second embodiment of the optical recording medium of the present invention), the lower limit of the reflective layer thickness is preferably 30 nm or more, more preferably 40 nm or more.

  The surface roughness Ra of the reflective layer 23 is preferably 5 nm or less, and more preferably 1 nm or less. Ag has a property that flatness is increased by the addition of an additive. In this sense, the content of the additive element is preferably 0.1 atomic% or more, and more preferably 0.5 atomic% or more.

  The reflective layer 23 can be formed by a conventionally known method such as sputtering, ion plating, or electron beam evaporation. Of these, the sputtering method is preferable. This is because the film thickness and composition are easy to control and the mass productivity is excellent.

(Recording layer 22)
The dye contained in the recording layer 22 of the optical recording medium 20 of the present invention is an organic compound having a remarkable absorption band due to its structure in the visible light (and its vicinity) wavelength region of 300 nm to 800 nm. In an unrecorded state (before recording) in which such a dye is formed as the recording layer 22, it has absorption at the wavelength λ of the recording / reproducing light beam 27, changes in quality due to recording, and the reflected light intensity of the reproducing light on the recording layer 22 A dye that causes an optical change that can be detected as a change in the color is called a “principal dye”. The main component dye may exhibit the above function as a mixture of a plurality of dyes.

  The main component dye content is preferably 50% or more, more preferably 80% or more, and still more preferably 90% or more in terms of weight%. As the main component dye, it is preferable that a single dye absorbs with respect to the wavelength λ of the recording / reproducing light beam 27 and is altered by recording to cause the above optical change. It may be functionally shared so as to indirectly change the other dye and cause an optical change by generating heat.

  In addition to this, a dye as a so-called quencher for improving the temporal stability (temperature, humidity, light stability) of a dye having a light absorption function may be mixed with the main component dye. Examples of the inclusion other than the main component dye include a binder (binder) made of a low-polymer material and a dielectric.

  The main component dye is not particularly limited by the structure. In the present embodiment, the refractive index is changed in the recording layer 22 by recording, and in principle, as long as the absorption coefficient in an unrecorded (before recording) state is a value larger than 0, the optical characteristics are not affected. There are no hard constraints. It suffices that the main component dye has absorption with respect to the wavelength λ of the recording / reproducing light beam 27, changes in quality due to its own light absorption and heat generation, and lowers the refractive index. Here, the alteration refers specifically to phenomena such as expansion, decomposition, sublimation, and melting due to absorption and heat generation of the main component dye. The coloring matter itself as the main component may be altered, accompanied by some structural change, and the refractive index may be lowered. The decrease in the refractive index may be a cavity formed in the recording layer 22 and / or the interface, or may be a decrease in the refractive index due to thermal expansion of the recording layer 22.

  The temperature exhibiting such alteration is preferably 100 ° C. or higher, more preferably 150 ° C. or higher, from the viewpoints of storage stability and reproduction light resistance. Further, from the viewpoint of jitter characteristics at a high linear velocity, 500 ° C. or lower is preferable, 350 ° C. or lower is more preferable, 300 ° C. or lower is more preferable, and 280 ° C. or lower is particularly preferable. If the decomposition temperature is 300 ° C. or lower, the jitter characteristic tends to be good particularly at a high linear velocity of 10 m / s or higher. It is preferable that the decomposition temperature is 280 ° C. or lower because there is a possibility of further improving the characteristics in high-speed recording. Usually, the alteration behavior described above is measured as the thermal characteristics of the main component dye, and the decomposition temperature can be measured as the weight reduction start temperature by the thermogravimetric analysis-differential thermal analysis (TG-DTA) method.

  Examples of the dye having the above characteristics include methine, (metal-containing) azo, hydrazide, pyrone, and porphyrin compounds, and mixtures thereof. More specifically, the metal-containing azo dyes, hydrazide dyes, and pyrone dyes are inherently excellent in light resistance, and have a temperature decrease starting temperature Td of TG-DTA of 150 ° C. or more and 400 ° C. or less. It is preferable in that it has a sharp weight loss characteristic (the decomposition product has high volatility and easily forms a cavity). Particularly preferred are metal-containing azo dyes and metal-containing hydrazide dyes. A pigment | dye may be used individually by 1 type, and may mix and use 2 or more types by arbitrary combinations and a ratio.

《Azo dyes》
As the azo dye, a metal-containing azo compound comprising an azo compound represented by the following formula [I] and a metal ion is preferable.

In the formula [I], ring A is a 5- or 6-membered saturated or unsaturated nitrogen-containing heterocyclic ring, and ring B is a 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring. Rings A and B may each be independently a 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring. X ¹ is a group having active hydrogen, and hydrogen is eliminated from X ¹ to form a complex with a metal ion.

  Ring A includes pyrrole, pyrazole, imidazole, oxazole, isoxazole, thiazole, isothiazole, triazole, oxadiazole, thiadiazole, indole, benzimidazole, benzoxazole, benzothiazole, isoindole, indazole, benzisoxazole, benzoiso Examples include thiazole, purine, pyridine, pyridazine, pyrimidine, pyrazine, triazine, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline and saturated rings thereof. Pyrazole, imidazole, isoxazole, triazole, pyridine, pyrimidine and the like are preferable. Particularly preferred are isoxazole, pyrazole and triazole.

  Ring B includes cyclopentanone, pyrrolidinone, thiophenone, pyrazolidinone, thiazolidinone, cyclopentadione, pyrozinedione, thiophenedione, pyrazolidinedione, indandione, cyclohexanone, pyranone, piperidinone, thiopyranone, cyclohexadione, pyrandionion, piperidinedione, Thiopyrandione, meldrum acid, barbituric acid, thiobarbituric acid, pyridone, benzene, pyridine, diketopyrimidine, pyridazine, pyrimidine, pyrazine, triazine, etc. Pyridone, pyrimidine, diketopyrimidine and the like are preferable. Particularly preferred are indandione, diketopyrimidine and meldrum acid.

Examples of X ¹ include a hydroxyl group, an amino group, and a sulfonamide group, and a hydroxyl group is preferable.
Examples of metal ions include divalent metal ions such as Ni, Co, Cu, Zn, Fe, and Mn. Particularly, when Ni and Co are contained, they are excellent in light resistance, high temperature and high humidity environment resistance. It is preferable.

<Hydrazide dye>
As the hydrazide dye, a metal-containing hydrazide compound composed of an azo compound represented by the following formula [II] and a metal ion is preferable.

In the formula [II], R is a 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring, or a 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring is divalent. A 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring may be further condensed to the above ring structure. Furthermore, R may be a chain alkyl group which may have a substituent.

Ring C is a 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring. Ring C is condensed with a 5- or 6-membered saturated or unsaturated hydrocarbon ring or heterocyclic ring. May be. X ² is a group having active hydrogen, and a hydrogen atom is eliminated from X ² to form a complex with a metal ion. Further, the hydrogen atom at the hydrazide moiety may be eliminated to form a complex with the metal ion.

  R is pyrrole, pyrazole, imidazole, oxazole, isoxazole, thiazole, isothiazole, triazole, oxadiazole, thiadiazole, indole, benzimidazole, benzoxazole, benzothiazole, isoindole, indazole, benzisoxazole, benzoisothiazole , Purine, benzene, pyridine, pyridazine, pyrimidine, pyrazine, triazine, quinoline, isoquinoline, cinnoline, quinazoline, quinoxaline and saturated rings thereof, and benzene, pyridine, imidazole and the like are preferable.

  The above structure may be bonded to methylene, ethylene, vinylene or phenylene to form R. It is also preferred that an ammonium salt such as pyridinium or imidazolium is formed in R. In this case, the counter anion may be coordinated with the metal-containing hydrazide compound, or an intramolecular anion site may be formed.

  As ring C, cyclopentanone, pyrrolidinone, thiophenone, pyrazolidinone, thiazolidinone, cyclopentadione, pyrozinedione, thiophenedione, pyrazolidinedione, indandione, cyclohexanone, pyranone, piperidinone, thiopyranone, cyclohexadione, pyrandionion, piperidinedione, Thiopyrandione, meldrum acid, barbituric acid, thiobarbituric acid, pyridone, benzene, pyridine, pyridazine, pyrimidine, pyrazine, triazine, etc. Etc. are preferable.

Examples of X ² include a hydroxyl group, an amino group, and a sulfonamide group, and a hydroxyl group is preferable.
Examples of metal ions include divalent metal ions such as Ni, Co, Cu, Zn, Fe, and Mn. Particularly, when Ni and Co are contained, they are excellent in light resistance, high temperature and high humidity environment resistance. It is preferable.

These azo dyes and hydrazide dyes are conventionally used in CD-R and DVD-R by selecting appropriate structures for ring A, ring B, ring C, X ¹ , X ² , R, and metal ions. The obtained azo dye can further have a main absorption band from a short wavelength, and the absorption coefficient k _d in the vicinity of 400 nm becomes a large value of about 0.3 to _{1, which} is preferable.

  The recording layer 22 can be formed by a coating method, a vacuum deposition method, or the like, but is particularly preferably formed by a coating method. That is, the recording material coating solution is prepared by dissolving the above-mentioned dye as a main component together with a binder, a quencher, and the like in a suitable solvent, and coating on the reflective layer 23 described above. The recording layer 22 is formed by drying the coating solution after coating.

  The concentration of the main component dye in the solution is usually 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 0.2% by weight or more, and usually 10% by weight or less, preferably 5% by weight. % Or less, more preferably 2% by weight or less. Thereby, the recording layer 22 is usually formed to a thickness of about 1 nm to 100 nm. In order to make the thickness less than 50 nm, the dye concentration is preferably less than 1% by weight, and more preferably less than 0.8% by weight. It is also preferable to further adjust the number of rotations of application.

  Solvents for dissolving the main dye material and the like include alcohols such as ethanol, n-propanol, isopropanol and n-butanol diacetone alcohol; fluorinated hydrocarbons such as tetrafluoropropanol (TFP) and octafluoropentanol (OFP) Solvents; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and propylene glycol monomethyl ether; esters such as butyl acetate, ethyl lactate, and cellosolve acetate; chlorinated hydrocarbons such as dichloromethane and chloroform; Hydrocarbons; ethers such as tetrahydrofuran, ethyl ether, dioxane; ketones such as methyl ethyl ketone, cyclohexanone, methyl isobutyl ketone It can be. These solvents are appropriately selected in consideration of the solubility of the main component dye material or the like to be dissolved, and two or more kinds can be mixed and used.

  As the binder, organic polymers such as cellulose derivatives, natural polymer substances, hydrocarbon resins, vinyl resins, acrylic resins, polyvinyl alcohol, and epoxy resins can be used. Further, the recording layer 22 can contain various dyes or anti-fading agents other than the dyes in order to improve light resistance.

  As the antifading agent, a singlet oxygen quencher is generally used. The amount of the anti-fading agent such as a singlet quencher is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more with respect to the material of the recording layer 22. Is 50% by weight or less, preferably 30% by weight or less, more preferably 25% by weight or less.

  In the present invention, for a dye having low light resistance, the light resistance can be improved by mixing other dye having good light resistance, for example, an organic dye compound conventionally used for CD-R and the like. The recording medium 20 can be improved to a practical level. It varies depending on the combination with the coupler component and the type of metal, but as an approximate trend, the light resistance tends to be higher due to the diazo component, and isoxazole and triazole, which are diazo components that are shorter in wavelength, tend to have lower wavelengths. In particular, longer thiazole, benzothiazole, and pyrazole have better light resistance. On the other hand, dyes with good light resistance tend to have low recording sensitivity due to low photosensitivity.

  In the present invention, the dye material used in the second embodiment described later needs to have higher recording sensitivity. Therefore, a light-containing azo dye AA containing isoxazole as a diazo component and having low light sensitivity (high recording sensitivity) and a light-containing azo dye BB containing pyrazole as a diazo component and having high light resistance and poor recording sensitivity are mixed. In this case, it is preferable to form the recording layer 22 containing a dye having good sensitivity and excellent light resistance by increasing the ratio of the AA dye to the BB dye.

  As described above, in the present invention, it is possible to supplement the recording characteristics by mixing two or more dyes having different characteristics.

(Interface layer 30)
In this embodiment, in particular, by providing an appropriate interface layer 30 between the recording layer 22 and the cover layer 24, the power margin during high-speed recording is improved, the generation of particles is reduced, and the raw material cost is reduced. can do.

The interface layer 30 of the present invention contains (In ₂ O ₃ —SnO ₂ ) and / or (In ₂ O ₃ —ZnO) as the main component M, and further includes Nb ₂ O ₅ , Ta ₂ O ₅ , TiO _2. , Y ₂ O ₃ , and LaF containing at least one material selected from subcomponent group A.

(In ₂ O ₃ —SnO ₂ ) in the present invention is a transparent conductive film generally called ITO (indium tin oxide), and is a mixture of indium oxide and tin oxide. The weight ratio of In ₂ O ₃ and SnO ₂ in ITO is often 9: 1 practically due to the balance between conductivity and transmittance, but the weight ratio of In ₂ O ₃ and SnO ₂ in the present invention is 9 The ratio is not limited to 1 and preferably 9.5: 0.5 to 6: 4.

(In ₂ O ₃ —ZnO) in the present invention is a mixture of indium oxide and zinc oxide (hereinafter sometimes referred to as indium zinc oxide). Indium zinc oxide is a transparent conductive film that is used as an alternative to ITO, and the weight ratio of In ₂ O ₃ and ZnO is often 9: 1 in practice, as in ITO. The weight ratio of In ₂ O ₃ and ZnO is not limited to 9: 1, and is preferably 9.5: 0.5 to 6: 4.

The interface layer 30 of the present invention contains (In ₂ O ₃ —SnO ₂ ) and / or (In ₂ O ₃ —ZnO) as the main component M. Regarding the content of the main component M, the total weight of (In ₂ O ₃ —SnO ₂ ) and (In ₂ O ₃ —ZnO) in the entire interface layer 30, that is, the weight ratio of the main component M in the interface layer 30 is usually It must be 50% or more. The weight ratio of the main component M in the interface layer 30 is preferably 60% or more, and more preferably 75% or more. Further, the weight ratio of the main component M in the interface layer 30 is usually 98% or less, preferably 95% or less, and more preferably 90% or less.

The interface layer 30 of the present invention further contains at least one material selected from the subcomponent group A consisting of Nb ₂ O ₅ , Ta ₂ O ₅ , TiO ₂ , Y ₂ O ₃ , and LaF. Among the subcomponent groups A, Nb ₂ O ₅ , Ta ₂ O ₅ and TiO ₂ are preferable, and Nb ₂ O ₅ is particularly preferable. The material selected from the subcomponent group A may be one type, or two or more types may be contained in any combination and ratio. The weight ratio of the material selected from the subcomponent group A in the interface layer 30 is usually 2% or more, preferably 5% or more, more preferably 10% or more, usually 50% or less, preferably 30% or less, more preferably. Is 20% or less.

Regarding the content of the material of the subcomponent group A, when the number of moles of the constituent molecules of the main component M in the interface layer is Ma and the number of moles of the constituent molecules of the subcomponent group A is Aa, Aa / (Ma + Aa) The content of the subcomponent group A represented by is usually 0.02 or more, preferably 0.04 or more, more preferably 0.09 or more, and usually 0.50 or less, preferably 0.20 or less. For example, when the main component M is (In ₂ O ₃ —SnO ₂ ) and the subcomponent group A is Nb ₂ O ₅ , the total number of molecules of In ₂ O ₃ and SnO ₂ in the interface layer 30 is Ma, Nb. _The number of atoms of ₂ O ₅ is Aa. When the content of the sub-component group A is greater than the lower limit, there is a tendency that a sufficient power margin improvement effect can be obtained. Conversely, when the content is less than the upper limit, the power margin can be improved while maintaining the recording sensitivity. Can be obtained.

  The details of the mechanism that improves the power margin in high-speed recording by using the interface layer of the present invention are unknown, but the present inventors have estimated as follows.

  First, the power margin in the present invention means that when a jitter, which is one of the most important indicators in the recording / reproducing characteristics of an optical recording medium, is measured by changing the laser power of the recording / reproducing light, a predetermined jitter value is obtained. This is an index indicating the range of laser power to be generated. Specifically, when the power that minimizes the jitter value is Pw (opt) and the range of the recording power that is less than or equal to the appropriately determined jitter value is Pw (Width), the power margin PM = Pw (Width) / Pw (Opt) * 100 [unit:%] should be large. The large power margin means that good jitter can be obtained in a wider laser power range, and good jitter can be maintained even with respect to fluctuations in laser power.

  One of the basic functions of the interface layer 30 in the optical recording medium 20 of the present invention is to prevent the dye material of the recording layer 22 from diffusing into the cover layer 24. Further, the dye recording layer by laser irradiation is used. It is thought to play a role in controlling the degree of deformation of the. This deformation state of the dye recording layer has a great influence on the recording / reproducing characteristics, and hence the jitter. Therefore, it is considered that the physical characteristics such as the hardness and elastic modulus of the interface layer 30 also affect the jitter. It is presumed that when the main component M of the interface layer 30 contains the predetermined subcomponent group A, the physical properties such as hardness become favorable and the power margin is improved.

  In the study of the present invention, the interface layer is formed by sputtering, but it is considered that the composition of the sputtering target and the actual film composition of the interface layer are almost the same. When the composition of the interface layer actually formed is analyzed, there may be oxygen vacancies or complex oxides in which oxygen is combined with two or more elements other than oxygen. It can be considered that the stoichiometric composition dominates the material properties. For example, when the film composition of the interface layer is analyzed, even if it is strictly deviated from the stoichiometric composition, the weight ratio of the composite oxide can be regarded as 5% or less of the entire interface layer, In the case where the ratio of oxygen in the total oxygen is 10% or less, the presence of these may be ignored. Therefore, the preferred composition range of each oxide molecule becomes unclear when considered as a strict oxide state including a reduced state, an oxygen deficient state, etc. Therefore, the molecular formula (oxidation) of each oxide used as a raw material at the time of target preparation The ratio of the number of moles of the molecule represented by the stoichiometric composition in which the ratio of the element species contained in the product is represented by an integer ratio and represented by the chemical unit formula of the minimum unit in which the total valence is ± 0) Stipulated by.

  The interface layer 30 of the present invention may be a mixture with other compounds as long as it contains at least one material selected from the main component M and the subcomponent group A. As other compounds, dielectric compounds such as oxides such as metals and semiconductors, nitrides, carbides, sulfides, fluorides such as magnesium (Mg) and calcium (Ca), and mixtures thereof are preferable. When mixing these other compounds, the kind is not limited to one kind, and two or more kinds of mixtures can be mixed in any combination and proportion. The total content of materials other than the main component M and the subcomponent group A contained in the interface layer 30 is preferably 5 mol% or more, more preferably 10 mol% or more. Moreover, 20 mol% or less is preferable. If it is within this range, it is preferable because the hardness becomes appropriate and the recording sensitivity is likely to be good.

  The film thickness of the interface layer 30 is preferably 1 nm or more, more preferably 5 nm or more, and particularly preferably 10 nm or more. Moreover, 50 nm or less is preferable, More preferably, it is 30 nm or less, Most preferably, it is 20 nm or less. If the film thickness is less than the above range, the effect of improving the power margin may not be sufficiently exhibited. If the film thickness is too thick, the recording sensitivity may be affected.

  The interface layer 30 can be formed by a conventionally known method such as a sputtering method, an ion plating method, or an electron beam evaporation method. In this, it is preferable to form by sputtering method from viewpoints, such as productivity.

(Cover layer 24)
The cover layer 24 is made of a material that is transparent to the recording / reproducing light beam 27 and has little birefringence. Usually, a plastic plate (hereinafter sometimes referred to as a sheet) is bonded with an adhesive, or the cover layer 24 is covered. After applying the coating solution containing the component for forming the film, it is cured by light, radiation, heat, or the like.

  The cover layer 24 preferably has a transmittance of 70% or more and more preferably 80% or more with respect to the wavelength λ of the recording / reproducing light beam 27.

  The plastic used as the material for the sheet is polycarbonate, polyolefin, acrylic, cellulose triacetate, polyethylene terephthalate, or the like. For adhesion, light, radiation curing, thermosetting resin, or pressure sensitive adhesive is used. As the pressure-sensitive adhesive, pressure sensitive adhesives made of acrylic, methacrylate, rubber, silicon, and urethane polymers can be used. These materials may be used alone or in a combination of two or more in any combination and ratio.

  For example, after a photocurable resin constituting the adhesive layer is dissolved in a suitable solvent to prepare a coating solution, this coating solution is applied onto the recording layer 22 or the interface layer 30 to form a coating film, and the coating film is formed. Overlay a polycarbonate sheet on top. Thereafter, the coating liquid is further stretched and developed by rotating the medium in a superposed state as necessary, and then cured by irradiating ultraviolet rays with a UV lamp. Alternatively, a pressure sensitive adhesive is applied to the sheet in advance, the sheet is overlaid on the recording layer 22 or the interface layer 30, and then pressed and pressed with an appropriate pressure.

  The pressure-sensitive adhesive is preferably an acrylic or methacrylate polymer pressure-sensitive adhesive from the viewpoint of transparency and durability. More specifically, 2-ethylhexyl acrylate, n-butyl acrylate, iso-octyl acrylate and the like are used as main component monomers, and these main component monomers are used as acrylic acid, methacrylic acid, acrylamide derivatives, maleic acid, hydroxyl ethyl acrylate, A polar monomer such as glycidyl acrylate is copolymerized. Glass transition temperature Tg, tack performance (adhesive force immediately formed when contacted at low pressure), peel strength by adjusting the molecular weight of the main monomer, mixing its short chain components, and adjusting the crosslink point density with acrylic acid The physical properties such as shear holding force can be controlled. As the solvent for the acrylic polymer, ethyl acetate, butyl acetate, toluene, methyl ethyl ketone, cyclohexane and the like are used. The pressure-sensitive adhesive preferably further contains a polyisocyanate-based crosslinking agent. An adhesive may be used individually by 1 type, and may mix and use 2 or more types by arbitrary combinations and a ratio.

  The pressure-sensitive adhesive is made of the above-mentioned material. A predetermined amount is uniformly applied to the surface of the cover layer 24 sheet that contacts the recording layer 22 side, and the solvent is dried. (When the interface layer 30 is provided, the surface thereof) is cured by applying pressure with a laminating roller or the like. When the sheet for the cover layer 24 coated with the pressure-sensitive adhesive is bonded to the surface of the recording medium on which the recording layer 22 is formed, it is preferably bonded in a vacuum so as not to entrain air and form bubbles. .

  In addition, after applying the pressure-sensitive adhesive on the release film and drying the solvent, the sheet for the cover layer 24 is bonded, and the release film is further peeled off to form the sheet for the cover layer 24 and the pressure-sensitive adhesive layer. After the integration, it may be attached to a recording medium.

  When the cover layer 24 is formed by a coating method, a spin coating method, a dip method, or the like is used. In particular, a spin coating method is often used for a disk-shaped medium. Similarly, as the material for the cover layer 24 by coating, urethane, epoxy, acrylic resin or the like is used, and after coating, it is cured by irradiating with ultraviolet rays, electron beams, radiation, and promoting radical polymerization or cationic polymerization. To do.

  The cover layer 24 may further be provided with a layer having a thickness of about 0.1 μm to 50 μm on the surface in order to impart functions such as scratch resistance and fingerprint resistance to the incident light side surface. The thickness of the cover layer 24 depends on the wavelength λ of the recording / reproducing light beam 27 and the NA (numerical aperture) of the objective lens 28, but is preferably 0.01 mm or more, more preferably 0.05 mm or more, and 0.3 mm or less. Is preferable, and 0.15 mm or less is more preferable. It is preferable that the entire thickness including the thickness of the adhesive layer, the hard coat layer, and the like be in an optically acceptable thickness range. For example, in a Blu-ray disc, it is preferable to control to about 100 μm ± 3 μm or less.

(Other configurations)
In the present embodiment, in addition to the interface layer 30 between the recording layer 22 and the cover layer 24 described above, the mutual contact / interaction of the layers is provided on each interface of the substrate 21, the reflective layer 23, and the recording layer 22. An interfacial functional layer can be inserted to prevent diffusion and adjust the phase difference and reflectivity. The interfacial functional layer may be a layer similar to the interfacial layer 30 or a layer having another material and configuration unless the effects of the present invention are significantly limited.

[2. Second Embodiment]
FIG. 2 is a view for explaining the configuration of the second embodiment of the optical recording medium of the present invention. In the second embodiment, the thickness of the reflective layer is reduced compared to the first embodiment, and a plurality of translucent reflective layers that transmit approximately 50% or more of the recording / reproducing light are provided. This is a multilayer recording medium that can be provided with a recording layer. That is, a recording medium in which a plurality of recording layers and a reflective layer (hereinafter collectively referred to as an information layer) are provided on a substrate.

  The optical recording medium 100 according to the second embodiment prevents signal interference between the reflective layer 103, the recording layer 102, and the interface layer 130 in contact with the recording layer 102 on at least the substrate 101 on which guide grooves are formed. An intermediate layer 114, a translucent reflective layer 113 that transmits approximately 50% or more of the recording / reproducing light, a recording layer 112, an interface layer 131 in contact with the recording layer 112, and a cover layer 111 are sequentially stacked. It has a structure. That is, it has two information layers. The optical recording medium 100 of the second embodiment also has a film surface incidence configuration.

(Substrate 101)
The substrate 101 can have the same configuration as the substrate 21 described above, and the material, manufacturing method, shape, thickness, and the like can also be the same.

(Information layer)
Of the two information layers, the information layer on which the recording / reproducing light beam 107 is incident is called the L1 layer, and the information layer on the far side is called the L0 layer.

  The L1 layer preferably has a transmittance of 50% or more. Therefore, if the translucent reflective layer 113 of the L1 layer is, for example, an Ag alloy, the thickness of the Ag alloy is preferably 1 nm or more, more preferably 5 nm or more, and preferably 50 nm or less, more preferably 30 nm or less, More preferably, it is preferably 20 nm or less. In addition, the material and formation method of the semitransparent reflective layer 113 can be the same as those of the reflective layer 23 described above. Further, the configuration, material, manufacturing method, shape, and the like of the recording layer 112 can be the same as those of the recording layer 22 described above.

  Since the L0 layer is not limited in transmittance, the configuration, material, manufacturing method, shape, and the like of the reflective layer 103 and the recording layer 102 can be the same as those of the reflective layer 23 and the recording layer 22 in the first embodiment. .

  Different layer configurations may be used for the L0 layer and the L1 layer, or the same layer configuration may be used. The compositions and materials of the recording layers 102 and 112 mainly composed of a dye used for each information layer may be different or the same.

  In the present embodiment, since the phase change is mainly used, it is expected that the amount of light transmitted through the L1 layer hardly changes before and after recording. This means that the amount of light transmitted to the L0 layer and the amount of light reflected from the L0 layer hardly change regardless of whether the L1 layer is recorded or not recorded. This is preferable because the layer can be recorded and reproduced.

(Intermediate layer 114)
A transparent intermediate layer 114 is provided between the L0 layer and the L1 layer in order to prevent signal interference.

  Examples of the material of the intermediate layer 114 include a radiation curable resin and a thermosetting resin. Of these materials, radiation curable resins are industrially preferred. Examples of the radiation curable resin include materials that are cured by irradiation with an electron beam or ultraviolet rays. However, in consideration of industrial productivity, it is preferable to use an ultraviolet curable resin. Examples of the ultraviolet curable resin include known radical ultraviolet curable resins and cationic ultraviolet curable resins, and any of them can be used.

  The intermediate layer 114 is formed by a manufacturing method known as a photopolymerization method (hereinafter referred to as “2P method”), which is known for a two-layer DVD-R or the like. Is preferred.

  In the case of the 2P method, the intermediate layer 114 is usually manufactured as follows. That is, first, an ultraviolet curable resin raw material or the like is applied onto the L0 layer to form a resin raw material layer, and then a stamper having a transfer uneven shape (hereinafter referred to as “transfer uneven shape” as appropriate). Is placed. Next, after the ultraviolet curable resin raw material is cured, the stamper is peeled off. In this manner, the uneven shape for transferring the stamper can be transferred to the surface of the ultraviolet curable resin, and the intermediate layer 114 having the uneven shape can be formed.

  The thickness of the intermediate layer 114 is, for example, about 25 μm in the optical system of the recording / reproducing light beam 107 having a wavelength λ = 405 nm and NA (numerical aperture) = 0.85. Similarly, the thickness distribution of the intermediate layer 114 is preferably about ± 2 μm or less.

(Cover layer 111)
The cover layer 111 can have the same configuration as the above-described cover layer 24, and the material, manufacturing method, shape, and the like thereof can also be the same. The thickness of the cover layer 111 is about 75 μm when the intermediate layer 114 is about 25 μm under the above-described conditions.
(Interface layer)

  In the second embodiment, an interface layer 131 is provided between the recording layer 112 and the cover layer 111. Further, an interface layer 130 may be provided between the recording layer 102 and the intermediate layer 114. When providing an interface layer at two or more locations, the components, thicknesses, etc. of each interface layer may be the same or different. The configuration, material, manufacturing method, shape, and the like of each interface layer can be the same as those of the interface layer 30 described above.

(Other configurations)
In the present embodiment, in addition to the interface layers 130 and 131 described above, the interfaces of the substrate 101, the reflective layer 103, the recording layer 102, the intermediate layer 114, the translucent reflective layer 113, the recording layer 112, and the cover layer 111. In addition, an interfacial functional layer can be inserted to prevent contact / diffusion between layers and to adjust phase difference and reflectance. The interfacial functional layer may be a layer similar to the interfacial layer, or may be a layer having other materials and configurations, unless the effect of the present invention is significantly limited.

[3. About optical recording apparatus used in the present invention]
The basic structure of the recording apparatus used in the present invention can be the same as that of a conventional optical recording apparatus. For example, conventionally known methods can be applied to the focus servo method and tracking servo method. It is only necessary that the spot at the focal position of the focused beam is applied to the cover layer groove portion 25 and follows the cover layer groove portion 25 by the tracking servo. Usually, a push-pull signal is used.

  When recording is performed on the cover layer groove 25, the focused recording / reproducing light beams 27 and 107 cause the main component dyes of the recording layers 22, 102, and 112 to rise in temperature and generate heat, thereby causing alteration (expansion, decomposition, sublimation). , Melting, etc.). When performing mark length modulation recording, the power (recording power) of the recording / reproducing light beams 27 and 107 is strongly modulated according to the mark length. The mark length modulation method is not particularly limited, and EFM modulation (CD), EFM + modulation (DVD), 1-7PP modulation (Blu-ray disc), etc., which are commonly used Run-Length-Limited codes, can be applied.

  However, in a recording / reproducing system based on the HtoL polarity signal, the polarity of the recording data signal may be reversed in advance so that the recording signal polarity at the mark and space is reversed during LtoH recording. In this way, the recorded signal can be apparently equivalent to a signal of HtoL polarity.

  Normally, the recording power is set to the high level Pw at the mark portion, and the low level Ps is set between the marks (spaces). Ps / Pw is usually 0.5 or less. Ps is a power that does not cause the above-described alteration in the recording layers 22, 102, and 112 by a single irradiation, and is used to preheat the recording layers 22, 102, and 112 before Pw. . Known recording pulse strategies are also used as appropriate in the recording method and recording apparatus of the present invention. For example, the recording power Pw irradiation time corresponding to the recording mark portion is further irradiated intermittently in a short time, modulated to a plurality of power levels, or after a certain time Ps from Pw irradiation until shifting to Ps. A recording strategy such as irradiation with a lower power level Pb can be used.

  Hereinafter, the present embodiment will be described in more detail based on examples. Note that this embodiment is not limited to the examples.

(Examples 1, 2, 3 and Comparative Example 1)
On a polycarbonate resin substrate on which a guide groove having a track pitch of 0.32 μm, a groove width of about 0.18 μm, and a groove depth of about 40 nm is formed, an Ag ₉₉ Bi _1.0 alloy target (composition is atomic%) is sputtered. A reflective layer having a thickness of about 20 nm was formed.

  In addition, a metal-containing azo dye AW composed of a ligand A represented by the following structural formula and divalent Ni, a ligand B composed of the following structural formula and a divalent Co A gold azo dye BW and a metal-containing hydrazide dye CW composed of divalent Co are mixed at a weight ratio of AW: BW: CW = 45: 30: 25, and 0.58 with tetrafluoropropanol (TFP). The mixed solution diluted to% by weight was formed by spin coating to form a recording layer.

  The conditions of the spin coating method are as follows. That is, the mixed solution was applied in the form of a ring of 0.6 g near the center of the disk, the disk was rotated at 250 rpm for 3 seconds to stretch the mixed solution, and then rotated at 7000 rpm for 2 seconds to shake off the mixed solution. . After application, the disk was kept in an environment of 40 ° C. for 20 minutes to evaporate and remove TFP as a solvent.

Thereafter, an In ₂ O ₃ —SnO ₂ —Nb ₂ O ₅ (75.0: 15.3: 9.7 mol%) target (Example 1), In ₂ O ₃ —SnO ₂ —Nb ₂ was formed on the dye recording layer. O ₅ (79.0: 16.2: 4.8 mol%) target (Example 2), In ₂ O ₃ —ZnO—Nb ₂ O ₅ (59.9: 22.7: 17.4 mol%) target ( Example 3) or an ITO (In ₂ O ₃ —SnO ₂ (83.0: 17.0 mol%)) target (Comparative Example 1) was sputtered to form an interface layer having a thickness of about 16 nm.
A 75 μm transparent cover layer was formed thereon by spin-coating an acrylic UV curable resin and curing it with a high-pressure mercury lamp.
The recording / reproduction evaluation of the produced optical recording medium was performed as follows.

[Recording / playback evaluation]
For recording / reproduction evaluation of an optical recording medium, an optical system having a recording / reproducing light wavelength λ = 406 nm, NA (numerical aperture) = 0.85, and a focused beam spot diameter of about 0.42 μm (area where the intensity is 1 / e ² ) is used. It was performed using ODU1000 tester manufactured by Pulstec.

  The optical recording medium was rotated at a linear velocity of 29.50 m / s (hereinafter referred to as 6x), and recording was performed by changing the power of the recording light. For reproduction, the linear velocity was 4.92 m / s, and the power of the reproduction light was 0.70 mW. A mark modulation signal (1-7PP) was used for recording. The reference clock period T was 15.15 ns (channel clock frequency 66 MHz).

(Jitter)
The jitter measurement is performed by equalizing the waveform of the recording signal with a limit equalizer and binarizing it. The time difference distribution σ between the rising edge and falling edge of the binarized signal and the rising edge of the channel clock signal is calculated. Measured by a time interval analyzer, and the reference clock period is defined as T, and σ / T × 100 (%) is defined as jitter (Data to Clock Jitter Data to Clock Jitter). As the jitter value is smaller, recording / reproduction with fewer errors is possible.

(Power margin)
As for the power margin, the recording power at which the jitter value is optimum, that is, the minimum recording power is Pwo, the recording power value at which the absolute value of the jitter is 10%, the recording power on the higher power side than Pwo is Pwh, and the recording power on the lower power side is When Pwl, it was determined by defining ((Pwh-Pwl) / Pwo) × 100 (%). It can be said that the larger the power margin value, the larger the margin of jitter with respect to the fluctuation of recording power during recording and reproduction, and the better the optical recording medium. In practical use, the power margin is preferably 30% or more.

[result]
Example 1 using In ₂ O ₃ —SnO ₂ —Nb ₂ O ₅ (75.0: 15.3: 9.7 mol%) for the interface layer, In ₂ O ₃ —SnO ₂ —Nb ₂ O ₅ (79.0: 16.2: 4.8 mol%) was used for Example 2, In ₂ O ₃ —ZnO—Nb ₂ O ₅ (59.9: 22.7: 17.4 mol%). Table 1 shows the content of the subcomponent group A represented by Aa / (Ma + Aa) and the value of the power margin obtained as described above. Show.

６ｘ記録において、比較例１のパワーマージンに比べて、実施例１〜３のパワーマージンは３０％以上の高い値が得られていることが判る。
即ち、本発明の界面層を用いることにより、高速記録におけるパワーマージンが改善されていることが明らかである。

In 6 × recording, it can be seen that the power margin of Examples 1 to 3 is higher than that of Comparative Example 1 by 30% or more.
That is, it is clear that the power margin in high-speed recording is improved by using the interface layer of the present invention.

20, 100 Optical recording medium 21, 101 Substrate 22, 102, 112 Recording layer 23, 103 Reflective layer 24, 111 Cover layer 25 Cover layer groove part 26 Cover layer groove part 27, 107 Recording / reproducing light beam 28, 108 Objective lens 29 109 The surface on which the recording / reproducing light beam is incident 30, 130, 131 Interface layer 113 Translucent reflective layer 114 Intermediate layer

Claims (4)

at least,
A substrate on which guide grooves are formed;
A reflective layer having a light reflecting function on the substrate;
A recording layer containing as a main component a dye having a light absorption function with respect to the recording / reproducing light wavelength in an unrecorded state;
An interface layer in contact with the recording layer;
In an optical recording medium comprising in this order a cover layer on which recording / reproducing light is incident on the recording layer,
The interface layer contains (In ₂ O ₃ —SnO ₂ ) and / or (In ₂ O ₃ —ZnO) as a main component M, and further includes Nb ₂ O ₅ , Ta ₂ O ₅ , TiO ₂ , Y _2. An optical recording medium comprising at least one material selected from subcomponent group A consisting of O ₃ and LaF.   Aa / (Ma + Aa) is 0.02 to 0.50, where Ma is the number of moles of constituent molecules of the main component M in the interface layer and Aa is the number of moles of constituent molecules of the subcomponent group A. The optical recording medium according to claim 1, wherein   Aa / (Ma + Aa) is 0.04 to 0.20, where Ma is the number of moles of constituent molecules of the main component M and Aa is the number of constituent molecules of the subcomponent group A in the interface layer. The optical recording medium according to claim 1, wherein The optical recording medium according to claim 1, wherein the interface layer contains Nb ₂ O ₅ .

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