JPH10228676A - Information recording medium and information recording and reproducing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an information recording medium having an information recording thin film as a recording layer in which the configuration of atoms is changed by irradiation of energy beams of form recording marks, and to enable rewriting in many times in this medium. SOLUTION: A first reflection layer formed nearer to a recording layer has a compsn. essentially comprising Al, Cu, Ag, Au, Pt, Pd, and the sum of the compsn. rations of these elements is controlled to >=65% and <=95%. The second reflection layer consists of an Al alloy or the like having a larger Al content than the first layer. Thereby, the obtd. medium has good recording sensitivity, good reproducing signal quality, enables repetition of recording and overwriting, and is compatible with a reproducing-only optical disk for reproducing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium on which information is recorded by irradiation of an energy beam, and an information recording / reproducing system comprising the information recording medium and an information recording / reproducing apparatus. An optical disc or a rewritable optical disc such as a magneto-optical disc, or an information recording / reproducing system for recording information on the optical disc and storing information, and information for reproducing information from the rewritable optical disc and the read-only optical disc The present invention relates to a recording and reproducing system.

In the present invention, the information recording medium is sometimes referred to as a phase-change optical disk, a magneto-optical disk, or simply an optical disk. In the present invention, heat is generated by irradiation of an energy beam, and the heat causes the atomic arrangement. Alternatively, the present invention can be applied to any information recording medium on which information is recorded by causing a change in the magnetic moment. Therefore, the information recording medium other than the disc-shaped information recording medium such as an optical card can be applied regardless of the shape of the information recording medium. It is also effective for information recording media.

[0003] The above-mentioned energy beam may be expressed as laser light or simply light. As described above, the present invention provides an energy beam that can generate heat on an information recording medium. It is also applicable to an information recording medium recorded by an energy beam which is not generally regarded as light, such as an electron beam, an ion beam, or an information recording / reproducing system which records information using these energy beams. is there.

[0004]

2. Description of the Related Art Generally, a rewritable optical disk has a structure in which a dielectric protective layer (hereinafter, referred to as a first protective layer) such as Si3N4 or ZnS-SiO2, a TbFeCo-based magnetic film, or A recording layer typified by a chalcogenide-based phase change film such as GeSbTe or the like, a dielectric protective layer (hereinafter, referred to as an intermediate layer) similar to the above-mentioned first protective layer are sequentially laminated, and a metal such as an Al alloy or an Au alloy is further laminated. This is a multiple interference structure provided with a reflective film. This structure is characterized by the refractive indices of the first protective layer and the intermediate layer,
Further, by setting the thicknesses of the recording layer, the intermediate layer, and the first protective layer to appropriate values, a change in the optical properties of the recording layer is emphasized to reflect light, thereby obtaining a large carrier-to-noise ratio. That is to be done. The role of the metal reflection film is to reflect light transmitted through the first protective layer, the recording layer, and the intermediate layer and return the light to the light incident side.

Further, after the optical property value of the recording layer is changed, the recording layer is cooled to prevent the recording layer from deteriorating and not to affect the already recorded adjacent recording marks. Therefore, what is required for the metal film is that it is required to have a high thermal conductivity in terms of heat. However, when the metal film has a high thermal conductivity, it means that the heat generated in the recording layer is easily diffused into the metal film, so that the temperature of the recording layer does not easily rise and the laser power required for recording is reduced. There is a problem that the recording sensitivity increases (recording sensitivity decreases).

On the other hand, an energy beam such as a laser beam is irradiated onto an information recording medium by modulating the energy between a high power level and a low power level, and a recording mark is recorded by utilizing heat generated thereby. In the information recording method, a so-called multi-pulse recording method is generally used for the purpose of controlling a mark shape. In the multi-pulse recording method, one recording mark is recorded by a plurality of high power pulses, so that the temperature distribution or cooling rate distribution on the information recording medium generated by the irradiation of the energy beam must be controlled to an appropriate distribution. Is possible. In addition, depending on the recording waveform (pulse shape of a series of high power pulse trains), the thermal load at the time of irradiation with the high power energy beam is drastically reduced, so that deterioration during multiple rewriting is suppressed.

[0007] Usually, these recording waveforms having a high effect of suppressing rewriting deterioration many times are immediately after irradiation of a high power pulse.
Since the power level is reduced to one-tenth or less of the high power level, the energy required for recording is insufficient.
Set the high power level high in advance. Therefore, when the recording sensitivity of the information recording medium is low, there is a problem that it is not possible to use a recording waveform having a high effect of suppressing rewriting deterioration many times.

As described above, in order to solve the problem caused by the low recording sensitivity of the information recording medium, two reflective layers are provided, and the thermal conductivity of the first reflective layer closer to the recording layer is reduced. A method is known in which a second reflective layer having a relatively high thermal conductivity is provided on the opposite side of the first reflective layer from the recording layer side (Japanese Patent Laid-Open No. 3-272032).

However, the low thermal conductivity metal which satisfies the above-mentioned thermal conditions has a low reflectance of 60% or less, so that the low thermal conductivity metal film sufficiently satisfies the above-mentioned optical characteristics as a reflection film. Therefore, it has been difficult to make the signal modulation degree of the reproduced signal, the CNR (carrier-to-noise ratio), the overall reflectance of the multiple interference structure, and the like sufficiently large.

In order to solve this problem, there is a method of laminating a semiconductor thin film such as Si having a high transmittance instead of the first reflection layer (Proceeding of International Symposium on).
Optical Memory 1995, pp 151-152). Although this method is an excellent method, in order to obtain an optically good multiple interference structure, the thickness of the semiconductor thin film should be 50 nm to 100 nm.
Therefore, there is a problem that the degree of freedom in design is reduced when performing thermal design. In addition, since a semiconductor thin film of Si or the like usually has a low film forming rate, it is not good in productivity, but there is a problem in mass production.

In addition, in the case of an information recording medium, such as an optical disk, which records and reproduces information by using a laser beam, reproduction compatibility with a read-only optical disk is a great demand in the market, and this is satisfied. That is very important. In particular, in systems such as compact discs and DVDs (digital video discs), reproduction compatibility between a rewritable optical disc or a write-once optical disc and a read-only optical disc is essential. In particular, the reproduction signal modulation degree (specified in each standard) is an item that requires compatibility that is more important than reflectance. Generally, the stability of tracking servo, focus servo, etc. is taken into consideration, the medium reflectivity is required to be 15% or more, and the reproduction signal modulation degree is required to be 50% or more in consideration of the signal quality of the reproduction signal. This is a condition for playback compatibility with the dedicated optical disk.

An information recording medium that satisfies this requirement is (Proceedings of Topical Meetingon Optical Data St.
orage, 1994, pp. 96-106), an information recording medium using a high-reflectance metal such as Au is known. Further, there is known an information recording / reproducing system or an information reproducing system for recording information modulated on the information recording medium by the same modulation method as that of a read-only optical disk.

However, in this method, Au is added to the intermediate layer.
However, there is a problem that data transfer speed at the time of recording is low because recording sensitivity cannot be said to be good because a metal having a high thermal conductivity such as an adjacent metal is adjacent, and recording can be performed only at a disk linear velocity of 3 m / s or less. Was. Further, there is a problem that an expensive semiconductor laser having an output of 50 mW or more must be used.

An information recording / reproducing system, such as a PD system, in which recording is improved by lowering the reflectivity of an information recording medium to enable recording at a high linear velocity, is known. Since it is not sufficient, there is a problem that recording (EFM recording) using the same mark edge recording method as a read-only optical disk (CD-ROM) cannot be performed. Further, since the EFM recording is not performed, the read-only optical disk (CD-ROM) reproducing apparatus uses the PD
There is a problem that the information recording medium for the system cannot be reproduced. Alternatively, since two types of reproduction signal demodulation circuits must be prepared, there is a problem that the reproduction system becomes expensive.

As a high-density recording method for a rewritable optical disk, a groove is provided on a transparent substrate, and a recording mark is recorded both in the groove (groove) and between the grooves (land) (land / groove recording). Method) is known. In this recording method, there is a problem that a phenomenon (so-called cross erase) of erasing a recording mark recorded on an adjacent track (an adjacent groove during land recording or an adjacent land during groove recording) is likely to occur.

Further, the phase change recording film of GeSbTe or the like has an advantage that information can be rewritten.

However, in this type of recording film, if a large number of rewriting operations exceeding 104 times are performed by the sample servo method, mark edge recording, etc.
The thickness of the recording film changes due to the flow of the recording film, causing distortion in the reproduction signal waveform. The flow of the recording film occurs when the recording film flows by laser irradiation at the time of recording and the recording film is gradually pressed by deformation due to thermal expansion of the protective layer and the intermediate layer.

For example, in Reference 1, “T. Ohta et al.“ Optica ”
l Data Strage "'89 Proc. SPIE, 1078, 27 (1989)" describes the use of thinner recording films to reduce the heat capacity and to increase the effect of adhesion to adjacent layers. In addition, a method for preventing the flow of is disclosed in Reference 2, "Hirotsune, Terao, Miyauchi, Minemura, Fushimi; Proceedings of p. A method of adding a component to prevent the recording film from flowing is disclosed, whereby large flow of the recording film can be suppressed.
However, if the rewriting is repeated more times, the reflectance level fluctuates.

In order to improve the overwrite jitter characteristic in mark edge recording, reference 3 [Okubo,
Murata, Ide, Okada, Iwanaga: Proceedings of the 5th Phase Change Recording Research Group, p98 ", proposes a disk having an increased transmittance of the reflective layer. This disc structure is
ZnS-SiO2 (250nm) / Ge2Sb2Te5 (15nm) / Z
nS-SiO2 (18 nm) / Si (65 nm).

On the other hand, an optical disk in which analog information signals obtained by FM-modulating video signals, audio signals, and the like, digital information signals such as computer data, facsimile signals, digital audio signals, and the like are transferred as irregularities on the substrate surface, laser light, In an optical disc having a recording thin film or the like capable of recording signals and data in real time with a recording beam such as an electron beam, the signal reproduction resolution is almost the same as the wavelength λ of the light source of the reproduction optical system and the objective lens. It is determined by the numerical aperture NA, and the recording mark period 2NA / λ is the reading limit.

As a method for increasing the recording density, a method of reproducing data recorded with irregularities using a medium whose reflectivity changes due to a phase change and a medium are described in K. Yasuda, M.
Ono, K.Aritani, A.Fukumoto M.Kaneko; Jpn.J.Appl.
Phys. Vol.32 (1993) p.5210]. Also in this method, the film for super-resolution reading causes a flow of the film when the reading is performed a large number of times exceeding 104 times,
Since the reflectivity level fluctuates, the number of readable times is limited.

In this specification, not only the phase change between the crystal and the amorphous phase, but also melting (change to the liquid phase) and recrystallization,
The term "phase change" is used to include the phase change between crystalline states.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems described in the above conventional example.
(1) The recording sensitivity is good, the effect of suppressing thermal interference between marks at the time of recording is high, the reliability of the reproduced signal after many rewrites is high, the reproduced signal quality is good, and it is suitable for high-density recording. To provide an information recording medium which has high mass productivity and satisfies reproduction compatibility with a read-only optical disc;
(2) High linear velocity recording of 3 m / s or more on an information recording medium using an inexpensive semiconductor laser with an output of 50 mW or less,
Another object of the present invention is to provide an information recording / reproducing system capable of performing mark edge recording / reproducing by the same modulation method as a read-only optical disk and reducing cross erase at the time of land / groove recording.

Furthermore, when any of the conventional information recording media is used as a rewritable phase transition type information recording medium, the problem is that the jitter increases and the reflectivity level fluctuates when the number of rewritable times is increased. have.

Similarly, when any of the conventional information recording media having a super-resolution reading film is used as a phase-change-type information recording medium capable of super-resolution reading, the number of times of super-resolution reading is increased. There is a problem that the reflectance level fluctuates.

Therefore, another object of the present invention is to maintain good recording / reproducing characteristics even when performing rewriting or super-resolution reading a number of times, and to reduce jitter rise more than before.
Another object of the present invention is to provide an information recording medium in which a change in reflectance level is small.

[0027]

In order to solve the above-mentioned problems in the prior art, the following information recording medium may be used. In the present invention, the reflective layer is composed of two or more layers, and is referred to as a reflective layer even when light does not reach the inner reflective layer. That is, (1) an information recording thin film on which information (recording mark) is recorded by a change in atomic arrangement and / or a change in electronic state by irradiation of an energy beam is provided as a recording layer, and the recording mark recorded on the recording layer is An information recording medium reproduced by energy beam irradiation, comprising at least a first reflection layer and a second reflection layer having different compositions on a side opposite to an energy beam incident side of the recording layer. The composition of the first reflective layer located on the side of Al, C
An information recording medium containing u, Ag, Au, Pt, and Pd as main components and having a total content of these atoms of 60% or more may be used.

Since metals such as Al, Cu, Ag, Au, Pt, and Pd have high reflectivity, by setting the composition of the first reflective layer as described above, the reflectivity of the first reflective layer is 60%. As described above, the reflectance can be set to 15% or more, which is sufficient for tracking servo and focus servo, and at the same time, the reproduction signal modulation degree can be set to 50% or more. In addition, since a plurality of reflective layers are provided, optical requirements can be satisfied by reflection of the first reflective layer, and thermal characteristics can be satisfied by heat conduction by other reflective layers.

In particular, the composition of the first reflection layer is Al, Cu, A
When g, Au, Pt, and Pd are the main components, and the sum of the composition ratios of these atoms is 70% or more and 85% or less, the thermal conductivity is 1/10 or less as compared with the case where the metal is used alone. Therefore, the recording sensitivity at the time of recording is improved.

Among these high reflectivity metals, A
l is relatively inexpensive because the reflectance has a small dependence on the light wavelength,
The most excellent point is that the thermal conductivity can be easily reduced by a small amount of additives. Therefore, (2) The information recording medium according to (1), wherein Al, C
u, Ag, Au, Pt, Pd, and Mo as main components, and having a second reflective layer in which the sum of the content of these atoms is larger than the sum of the content of these atoms in the first reflective layer. Characteristic information recording medium.

(3) The information recording medium according to (1), further comprising a first reflective layer containing 65% to 95% Al.
In particular, (4) The information recording medium according to (1) or (2),
Ti, Cr, Co, Ni, Mg, S
i, V, Ca, Fe, Zn, Zr, Nb, Mo, Rh,
Sn, Sb, Te, Ta, W, Ir, Pb, B and C
An information recording medium characterized in that at least one element selected from the group consisting of a main component is added as a main component, whereby an information recording medium having a first reflective layer having high reflectivity, low thermal conductivity, and high intensity is provided. Since the medium can be used as a medium, the above object can be achieved. Also, if the film thickness of the first reflective layer is too thin, optical or thermal requirements cannot be satisfied, and if too thick, thermal requirements cannot be satisfied, Productivity deteriorates. Therefore, the first reflective layer has an optimal film thickness. The optimum thickness of the first reflection layer is 30 nm to 300 nm. Therefore, (5) The information recording medium according to (1) to (3),
The above object can be achieved with an information recording medium characterized in that the first reflective layer has a thickness of 30 nm or more and 300 nm or less. In particular, when the thickness of the first reflective layer is 5
When the thickness is 0 nm or more and 200 nm or less, and when the thickness is 50 nm or more and 150 nm or less, the optical, thermal, and productivity are the most excellent and are preferable.

Further, a second reflective layer having a different composition from the first reflective layer is provided on the opposite side of the first reflective layer from the light incident side, and the composition of the second reflective layer is made to have a higher thermal conductivity than the first reflective layer. The information recording medium shown in (5) has a high effect of suppressing thermal interference between marks during recording, has a good reproduction signal quality, and has high mass productivity. Can be provided.

In particular, Al can easily adjust the thermal conductivity, has high strength, and is relatively inexpensive, so it is excellent. Particularly preferred.

(6) The information recording medium according to (5), further comprising a second reflective layer containing 90% or more of Al.

(7) The information recording medium according to (5) or (6), wherein the second reflective layer has a thickness of 50 nm or more and 25 nm or more.
An information recording medium having a thickness of 0 nm or less. When the first reflective layer having a reflectance of about 60% as shown in (1) to (7) is used as the reflective layer, if the reflectance is set to 15% or more that enables tracking servo, focus servo, and the like. At the same time, 50
In order to obtain a reproduction signal modulation degree of not less than%, the configuration of the thin film located on the light incident side of the reflection layer is important.

(8) By using the information recording medium shown in (9) and (10), 60
% Is particularly preferable because a relatively high reflectance and a high signal modulation can be obtained even when the first reflection layer having a reflectance of about% is used as the reflection layer. In particular, as shown in (9), Zn and S are contained in the first protective layer or the intermediate layer so that the composition ratio of Zn and S is close to 1: 1 for example, whereby high reliability and high reliability are achieved. It is preferable because a protective layer having a refractive index and a low thermal conductivity can be obtained.

(8) The information recording medium according to any one of (1) to (7), further including a transparent substrate at least on the energy beam incident side, wherein a transparent substrate is provided between the transparent substrate and the first reflective layer. An information recording medium comprising two protective layers, one protective layer and an intermediate layer, and a recording layer between the first protective layer and the intermediate layer.

(9) The information recording medium according to (8), wherein at least one of the first protective layer and the intermediate layer contains Zn and S.

(10) The information recording medium according to (9), wherein, of the first protective layer and the intermediate layer, the first protective layer closer to the transparent substrate has a thickness of 50 nm or more and 100 nm or less. An information recording medium, wherein the thickness of the recording layer is 5 nm or more and 30 nm or less, and the thickness of the intermediate layer is 10 nm or more and 40 nm or less.

(11) The information recording medium according to (10), further comprising a second protective layer containing a compound of Al and O between the first protective layer and the recording layer. Information recording medium.

(12) The information recording medium according to (11), wherein the thickness of the second protective layer is 2 nm or more and 20 nm or less. Degree, and the reflectance and reproduction signal modulation degree do not fluctuate even when rewriting many times.
The playback compatibility with the read-only optical disc can be satisfied.

In general, Ge, Sb, Te, In, Ag
In the case of using a so-called phase change recording method in which information is recorded using a phase change between a crystal and an amorphous state by using a recording layer such as a recording layer, deterioration occurs due to recording film flow at the time of rewriting many times. To cope with this, the thickness of the metal layer may be increased. However, when a metal layer having a high thermal conductivity is provided at 200 nm or more adjacent to the intermediate layer, the recording sensitivity is reduced and the thermal interference between recording marks is reduced. This causes problems such as an increase in the number of particles, which is not preferable.
In the information recording medium described in (1) to (12), since the first reflection layer having a relatively low thermal conductivity is provided between the second reflection layer having a high thermal conductivity and the intermediate layer, the recording sensitivity is reduced. The total thickness of the reflective film can be increased without causing the reflection. Especially (1
When the sum of the film thicknesses of the first reflective layer and the second reflective layer is 130 nm or more and 400 nm or less, particularly 200 nm or more and 300 nm or less as in the information recording medium shown in 3), the mass productivity and the effect of suppressing the flow of the recording film are high. In point, it is even better.

(13) The information recording medium according to (8), wherein the sum of the thicknesses of the first reflective layer and the second reflective layer is 130.
An information recording medium characterized by being not less than 400 nm and not more than 400 nm.

Further, in order to further improve the optical characteristics of the information recording medium shown in (1) to (13), a third reflective layer having a higher reflectance than the first reflective layer is provided between the intermediate layer and the first reflective layer. It is also possible to provide them between them, as shown in (14) to (16).

(14) The information recording medium according to (8), wherein Al, Cu, and A are provided between the first reflective layer and the recording layer.
An information recording medium comprising g, Au, Pt, and Pd as main components, and having a third reflective layer in which the sum of the contents of these atoms is larger than the first reflective layer.

(15) The information recording medium according to (14), further comprising a third reflective layer containing 90% or more of Al.

(16) The information recording medium according to (14), wherein the first reflective layer and the third reflective layer are adjacent to each other, and the thickness of the third reflective layer is 30 nm or less. Information recording medium.

When a non-metal layer having a low thermal conductivity is provided between the first reflection layer and the second reflection layer as shown in (17), the thermal characteristics are further improved, and the recording sensitivity is improved. In addition, thermal interference between recording marks can be suppressed.

(17) The information recording medium according to (8), wherein the thickness is 200 n between the first reflection layer and the second reflection layer.
An information recording medium having a non-metal layer of m or less.

Further, the present invention relates to an information recording medium of a system (land / groove recording system) in which a groove is provided on a transparent substrate and recording marks are recorded both in the groove (groove) and between the grooves (land). Is especially effective. First
The presence of the reflective layer makes it difficult for heat generated during recording to affect adjacent tracks (adjacent grooves during land recording or adjacent lands during groove recording). This is because an erasing phenomenon (so-called cross erase) is unlikely to occur. Therefore, when the track pitch is the energy beam diameter (when the laser beam is used as the energy beam, the laser wavelength is λ, and the numerical aperture of the objective lens for focusing the laser on the information recording medium is NA,
(corresponding to λ / NA), no cross erase occurs. Therefore, by combining the land / groove recording method and the present invention as in the information recording medium shown in (18), further high-density recording can be realized.

Another feature of the recording medium of the present invention is that the protective layer of the recording medium is a two-layer laminated film. First
The protective layer 2 is made of (ZnS) ₈₀ (SiO ₂ ) ₂₀ (molar ratio) or, alternatively, a slightly lower recording sensitivity and jitter, but with a different mixture ratio of ZnS and SiO ₂ (SiO ₂ is 15 to 20 mol%), and a material having a composition close to the mixed composition of ZnS and the following oxide 10 to 40 mol% is preferable. The mixed oxide is SiO ₂ , SiO, TiO ₂ , A
l ₂ O ₃ , Y ₂ O ₃ , CeO, La ₂ O _3, In ₂ O ₃ , Ge
O, GeO ₂ , PbO, SnO, SnO ₂ , Bi ₂ O ₃ , T
eO ₂ , WO ₂ , WO ₃ , Sc ₂ O ₃ , Ta ₂ O ₅ and ZrO ₂ are preferred. In addition, Si-ON-based materials, Si-Al-
O-N-based material, Cr-O-based material such as Cr ₂ O _3,, Co
Oxides such as Co—O-based materials such as ₂ O ₃ and CoO;
Si, N-based materials such as N, AlN, Si ₃ N ₄ , nitrides such as Al-Si-N-based materials (eg, AlSiN ₂ ), Ge-N-based materials, and Zn
S, Sb ₂ S ₃ , CdS, In ₂ S ₃ , Ga ₂ S ₃ , GeS,
Sulfides such as SnS ₂ , PbS, Bi ₂ S ₃ , etc., SnS
e ₃ , Sb ₂ S ₃ , CdSe, ZnSe, In ₂ Se ₃ ,
Ga ₂ Se ₃ , GeSe, GeSe ₂ , SnSe, PbS
e, selenides such as Bi ₂ Se ₃ , CeF ₃ , Mg
A protective layer using a fluoride such as F ₂ or CaF ₂ , or a material having a composition close to the above materials may be used. Further, a layer of these mixed materials may be used. It is advantageous to form a multi-layered protective layer in which a protective layer made of ZnS and an oxide and a second protective layer made of the above-mentioned material, which are different in composition, are stacked. In this case, among materials other than the above-mentioned material composed of ZnS and oxide, any one of oxide, nitride, and fluoride is more preferable.

Other than the above, as a material instead of Al ₂ O ₃ of the second protective layer, a material mainly composed of Al ₂ O ₃ , Si 2
A material containing O ₂ or SiO ₂ as a main component is more preferable because it can reduce a rise in jitter which is observed in the vicinity of the number of times of rewriting of the trailing edge of 10 to 100 times.

The effect of the second protective layer is to prevent the reflectance from being changed by multiple overwrites due to the mutual diffusion of the material of the first protective layer and the material of the recording film. If less than 2 nm, the effect was small. Above 2 nm, the change in reflectance can be suppressed to 3% or less of the practical level.
Then, the change in reflectance was 2%. At a film thickness larger than that, the change in reflectance is not much different from the case of 4 nm. Since the material of the second protective layer has a higher thermal conductivity than (ZnS) ₈₀ (SiO ₂ ) ₂₀ , the thickness of the second protective layer is preferably in the range of 2 nm to 20 nm, particularly preferably in the range of 4 nm to 8 nm.
Such a two-layer protective layer has a structure in which the first reflective layer of the present invention is not provided, the first reflective layer is made of Si, and furthermore, 50% or more of read light is transmitted between the substrate and the first protective layer. In other laminated structures, such as a laminated structure in which another layer is added, such as a laminated structure in which a thin metal layer is added, the effect of preventing the adverse effect due to the diffusion of the first protective layer material into the recording film can be obtained. Yes.

A second material made of any material which can be used also for the second protective layer between the recording film and the intermediate layer.
Providing the intermediate layer further enhances the effect. The thickness may be the same as that of the second protective layer.

(18) The information recording medium according to (1), further comprising a substrate provided with a groove, for recording a recording mark both in the groove (groove) and between the grooves (land). An information recording medium provided with an address information mark. Further, as shown in (19), by combining the information recording medium described in (18) with an information recording / reproducing apparatus capable of land / groove recording,
An information recording / reproducing system capable of high-density recording is realized.

(19) An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing device for recording information on the replaceable information recording medium, wherein the information recording medium described in (18) A laser beam irradiating means for forming a recording mark on an information recording medium, and an address information detecting means for detecting address information from an electric signal obtained by reproducing the address information mark provided on the information recording medium An information recording / reproducing system comprising an information recording / reproducing device having:

By the way, the information is converted into a plurality of lengths of two-level electric signal of high voltage and low voltage, and recording marks of a plurality of lengths corresponding to the electric signal are recorded on an information recording medium. A recording method for restoring information by detecting a portion corresponding to an edge of a recording mark of an electric signal reproduced from the recording marks having a plurality of lengths (mark edge recording method) is based on a high-density information recording medium. Suitable for recording. By combining this mark edge recording method with the information recording medium of the present invention, higher density recording is realized. In the information recording medium of the present invention, since the influence of thermal interference between marks during recording is suppressed as much as possible, even when performing mark edge recording, it is possible to control the length of the recording mark to an appropriate length. It is possible. Especially,
At the same time as recording marks as small as 70% or less of the above-mentioned λ / NA, recording marks twice or more of λ / NA can be recorded. In particular, the information recording medium of the present invention has an optical wavelength of 6
It is possible to record a recording mark of 0.2 to 0.7 micron when using a laser beam focused from a laser of 00 to 700 nm by an objective lens with a lens numerical aperture of 0.56 to 0.66. Not only that, a relatively long recording mark of 3 microns or more can be recorded with high accuracy. Therefore, the following information recording media (20) and (22) are suitable for high-density recording of information.

Further, in the information recording / reproducing systems described in (21) and (23), in which the information recording medium described in (20) and (22) is combined with an information recording / reproducing apparatus for recording information on the medium, the information recording medium has a high density of information. Not only can recording be performed, but also an inexpensive playback compatible system with a read-only optical disc is realized.

(20) The information recording medium according to (1), (8), or (18), wherein the information is recorded by a method of recording recording marks of a plurality of lengths corresponding to an information signal. Information recording medium.

(21) An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on the replaceable information recording medium, wherein the information recording medium described in (20) A laser beam irradiation means for forming a recording mark on an information recording medium, and a recording signal modulation circuit and a reproduction signal demodulation circuit for performing recording by a method of recording recording marks of a plurality of lengths corresponding to an information signal An information recording / reproducing system comprising an information recording / reproducing device having:

(22) The information recording medium according to (20), wherein the energy beam for recording a recording mark is:
A laser beam having a light wavelength of 600 to 700 nm condensed by an objective lens having a numerical aperture of 0.56 or more and 0.66 or less is used, and the shortest recording mark length of the plurality of length recording marks is 0.5. An information recording medium having a size of not less than 2 microns and not more than 0.7 microns.

(23) An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on the replaceable information recording medium, wherein the information recording medium described in (22) A laser beam irradiating means for converging a laser beam having a light wavelength of 600 to 700 nm by an objective lens having a lens numerical aperture of 0.56 or more and 0.66 or less; An information recording / reproducing system comprising an information recording / reproducing apparatus having a recording waveform generating circuit for controlling an irradiation time of an energy beam for recording a shortest recording mark so as to be not less than 0.2 μm and not more than 0.7 μm. .

When used in a method of recording information by irradiating a laser beam of a certain level and modulating the direction of an external magnetic field (magnetic field modulation recording method) as represented by a magneto-optical disk. Although the information recording medium of the present invention is suitable for the above method, a particularly great effect is exhibited when the information recording medium is used in a system for recording information by modulating the power level of an energy beam (laser beam) (light intensity modulation system). I do. That is, in the case of light intensity modulation recording, in a normal information recording medium, since heat is easily transmitted on the recording layer plane, this heat is applied to the shape of a recording mark recorded before or the shape of a recording mark recorded later. Although this effect is likely to occur (this phenomenon is referred to as inter-mark thermal interference), in the information recording medium of the present invention, heat is selectively diffused from the first reflective layer to the second reflective layer. This is because diffusion can be suppressed as much as possible. Therefore, (24) The information recording medium according to (1), (8), or (18), wherein recording is performed using at least the first power level and the second power level as the power level of the energy beam. The above object is achieved by an information recording medium characterized by having a recording layer that changes to a first state by irradiation at a first power level and to a second state by irradiation at a second power level. be able to. Also, (2
5) An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing device for recording information on the replaceable information recording medium, wherein the information recording medium according to (24);
(24) An information recording / reproducing system comprising an information recording / reproducing device having a power level modulation circuit for modulating the power level of the energy beam between a first power level and a second power level. The recording / reproducing system for the information recording medium described in (1) is realized.

Here, the first state and the second state indicate a state in which the direction of the magnetic moment of the recording layer or the direction of the Kerr rotation of the linearly polarized light has changed in the case of a magneto-optical disk. In this case, it refers to an amorphous state and a crystalline state. In addition, in the case of organic dye recording in which recording is performed by changing the shape of a substrate or a recording layer, a change occurs only when a high-power laser beam is irradiated, and this change is irreversible. Is to generate heat by an energy beam, and to control the thermal characteristics (temperature distribution, cooling rate distribution) as well as the optical characteristics (reflectance, modulation degree) of the information recording medium on which the recording mark is recorded by the heat. However, the present invention is not particularly limited to a rewritable information recording medium.

However, as described above, the information recording medium of the present invention exerts a particularly great effect on an information recording medium compatible with the phase change recording method as shown in (26). This is because, in the phase change recording method, the flow or the shape change of the recording layer is generally likely to occur at the time of rewriting many times, but the information recording medium of the present invention can easily suppress such deterioration.

(26) The information recording medium according to (1), (8) or (18), wherein the first power level is higher than the second power level, and the first state is an amorphous state. The above object can be achieved by an information recording medium characterized in that the second state is a crystalline state. (27) An information recording / reproducing system including a replaceable information recording medium and an information recording / reproducing device for recording information on the replaceable information recording medium, wherein the information recording medium according to (26), An information recording / reproducing apparatus having a power level modulation circuit for modulating the power level of the energy beam between a first power level and a second power level lower than the first power level. The information recording / reproducing system realizes a recording / reproducing system for the information recording medium described in (26).

In the case of the information recording medium described in (26), there is an optimum region in the composition of the recording layer, and the information recording medium described in (28) and the information recording / reproducing system described in (29) Enables recording and reproduction of information at a disk linear velocity of 3 to 12 m / s. Particularly, when recording video information compressed by an image compression method such as MPEG2, or on a read-only optical disc, An information recording medium and an information recording / reproducing system adapted to a case where a video compressed by the above method is recorded are realized.

(28) The information recording medium according to (26), wherein at least Ge, Sb, Te is a main component,
e, Sb, Te, Ag, In, Co, Se, Ti, C
r, Ni, Mg, Si, V, Ca, Fe, Zn, Zr,
An additional element M comprising at least one element selected from the group consisting of Nb, Mo, Rh, Sn, Ta, W, Ir, Pb, B and C is added, and the composition ratio is (Ge2Sb2T).
e5) (1-x) + Mx (provided that 0.015 <x <0.2
0) An information recording medium comprising a recording layer.

(29) An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on the replaceable information recording medium, wherein the information recording medium described in (28) An information recording / reproducing apparatus having a power level modulation circuit for modulating the power level of the energy beam between a first power level and a second power level lower than the first power level. Information recording and playback system.

A feature of the phase change optical disk is that, similar to the read-only optical disk, the magnitude of the reflected light amount is converted into a voltage level to reproduce information. To take advantage of such features and satisfy compatibility with a read-only optical disk, the information recording medium of the present invention described in (30) or (32) may be used. By using such an information recording medium, the reproduction compatibility with a read-only optical disk is satisfied optically, the mark edge recording characteristics are excellent thermally, and the recording film flow suppressing effect at the time of rewriting many times. Is obtained. Further, the information recording / reproducing system described in (31) and (33) realizes an inexpensive information recording / reproducing system capable of reproducing a read-only optical disk.

(30) The information recording medium according to (1), (8), or (18), wherein the level of the reflected light level when the energy beam is irradiated is converted into an electric signal to thereby obtain information. An information recording medium on which reproduction is performed, and using an energy beam defined in a standard relating to recording and reproduction of the information recording medium, the information recording medium has a width that is equal to or less than half the width of the energy beam and is equal to or greater than one time. The ratio (Rr / Rn) of the reflected light level Rr from the recording mark in the amorphous state recorded with the length of the recording mark to the reflected light level Rn from the portion where the recording mark is not recorded (crystal state) is 0.5. An information recording medium characterized by being less than or equal to 2.0 or more.

(31) An information recording / reproducing system comprising a replaceable information medium and an information recording / reproducing apparatus for reproducing the replaceable information medium, wherein the information recording medium and the read-only information medium according to (30) are provided. 31. An energy beam irradiating means for irradiating at least two types of information mediums, and an energy beam irradiating means for irradiating an energy beam, and a photoelectric element for converting a level of light reflected from an information recording medium and a read-only information medium into an electric signal An information recording / reproducing system comprising an information recording / reproducing device having conversion means.

(32) The information recording medium according to (30), wherein the highest reflected light level Rh is 15 to 2
An information recording medium characterized by being 4%.

(33) An information recording / reproducing system comprising a replaceable information medium and an information recording / reproducing apparatus for reproducing the replaceable information medium, wherein the information recording medium and the read-only information medium according to (32) are provided. And an energy beam irradiating means for irradiating an energy beam, and a photoelectric converter for converting a level of light reflected from an information recording medium and a read-only information medium described in (32) into an electric signal. An information recording / reproducing system comprising an information recording / reproducing device having conversion means.

(34) The information recording medium according to (8), further comprising a second protective layer between the first protective layer and the recording layer, wherein the second protective layer is composed of an oxide, a nitride, An information recording medium characterized by being one of the following:

(35) The information recording medium according to (34), wherein the thickness of the second protective layer is 2 nm or more and 20 nm or less.

(36) The information recording medium according to (34), further comprising a second intermediate layer between the intermediate layer and the recording layer, wherein the second intermediate layer is formed of an oxide, a nitride, or a fluoride. An information recording medium characterized by any one of the above.

(37) As a recording layer, an information recording thin film formed on a substrate directly or via an underlayer and recording and / or reproducing information by a change in atomic arrangement caused by irradiation of an energy beam is provided. And a protective layer, and at least two or more reflective layers, wherein the reflective layer comprises a first reflective layer and a second reflective layer made of a material having at least one of a different refractive index or extinction coefficient, and a light incident side. , A protective layer and a recording layer in this order, and then a first reflective layer and a second reflective layer in that order, or via an intermediate layer.

(38) In the information recording medium according to (1) or (37), the difference between the refractive index and the extinction coefficient of the first reflective layer and the second reflective layer is 0.5 or more, and The difference between at least one of the refractive index and the extinction coefficient between the reflective layer and the second reflective layer is 2 or less.

(39) In the information recording medium according to (1) or (37), the first reflective layer has a refractive index of 5 or less, the second reflective layer has a refractive index of 2 or less, and the first reflective layer has a refractive index of 2 or less. The information recording medium according to claim 1, wherein the extinction coefficient of the reflection layer is 5 or less, or the extinction coefficient of the second reflection layer is 5 or more.

(40) The information recording medium according to (1) or (37), further including a third reflective layer on the other layer side of both the first reflective layer and the second reflective layer. And

(41) In the information recording medium according to (1) or (37), the thickness of the third reflective layer is equal to the thickness of the first reflective layer.
It is characterized in that it is thinner than any of the thicknesses of the reflection layer and the second reflection layer.

(42) In the information recording medium according to (1) or (37), the total number of atoms of the second reflection layer is 90%.
% Or more of the components is Al-Ti, Al-Ag, Al-Cu, A
It is characterized by being made of one of l-Cr and Al-Co.

(43) The information recording medium according to (1) or (37), wherein the total number of atoms of the second reflective layer is 90%.
% Or more of the components are made of any one of Al, Au, Cu, and Mo.

A component of 90% or more of the total number of atoms of the first reflection layer is made of Si, and a component of 90% or more of the total number of atoms of the second reflection layer is Al-Ti, Al-Ag, Al- C
38. The information recording medium according to claim 1, comprising at least one of u, Al-Cr, and Al-Co.

[0086] A component that is 90% or more of the total number of atoms of the first reflective layer is Si, Si-Ti, Si-Mo, Si-Al, S
A component consisting of at least one of i-Ge and Ge and having 90% or more of the total number of atoms of the second reflective layer is Mo,
The information recording medium according to claim 1, comprising at least one of Mo compounds.

(44) The information recording medium according to (1) or (37), wherein 95% or more of the total number of atoms of the recording film is made of Ge-Sb-Te.

(45) (1) or (37) to (44)
In the information recording medium according to any one of the above, the component of 90% or more of the total number of atoms of the recording film has Ag of 1 to 5 atomic%, Ge of 17 to 25 atomic%, and Sb of 19 to 19 atomic%.
25 atomic%, and Te is in the range of 53 to 59 atomic%.

(46) (1) or (37) to (45)
In the information recording medium described in any one of (1) to (5), a component having 90% or more of the total number of atoms of the recording film has a composition close to AgSbTe2, and a balance of Ge2Sb2Te5.
Characterized by a material having a composition close to

(47) (1) or (37) to (46)
The information recording medium according to any one of the above, wherein the first reflective layer is directly laminated on the recording film.

(48) (1) or (37) to (47)
The information recording medium according to any one of the above, further comprising an intermediate layer between the recording layer and the first reflective layer.

(49) In the information recording medium described in (48), a component having 90% or more of the total number of atoms of the intermediate layer is Z
nS.

(50) In the information recording medium described in (48), the intermediate layer has a Z component of 90% or more of the total number of atoms.
It is characterized by comprising two layers of a film made of nS and a film made of Al oxide in which 90% or more of the total number of atoms are contained.

(51) The information recording medium according to (48), wherein a component of 10 to 40 atomic% of the total number of atoms of the intermediate layer has an Al—O composition.

(52) In the information recording medium described in (48), a component having 90% or more of the total number of atoms of the intermediate layer is (ZnS)-(Al2O3) or (ZnS)-(Al2O3).
-(SiO2), (Al2O3)-(SiO2).

(53) (1) or (37) to (52)
In the information recording medium described in any one of the above, a component of 10 at% to 40 at% of the total number of atoms of the protective layer is made of Al-O.

(54) (1) or (37) to (53)
In the information recording medium described in any one of the above, the protective layer is a film in which a component having 90% or more of the total number of atoms is made of ZnS;
The film is characterized by comprising two layers of a film made of -Si-O.

(55) In the information recording medium according to (54), the protective layer may be made of Al-O or Al-Si.
The film thickness of the -O film is 2 nm or more and 20 nm or less.

(56) (1) or (37) to (55)
In the information recording medium according to any one of the above, a component having 90% or more of the total number of atoms of the protective layer is (ZnS)-(A
(II2O3) and (ZnS)-(Al2O3)-(SiO2).

(57) (1) or (37) to (56)
In the information recording medium described in any one of the above, the film thickness of the recording film is in a range of 10 nm or more and 30 nm or less.

(58) (1) or (37) to (57)
In the information recording medium described in any one of the above, the thickness of the protective layer is in a range of 60 nm or more and 110 nm or less.

(59) Any one of (48) to (52)
In the information recording medium described in (1), the thickness of the intermediate layer is in a range of 15 nm or more and 30 nm or less.

(60) (1) or (37) to (59)
In the information recording medium described in any one of the above, the film thickness of the first reflective layer is in a range of 50 nm or more and 200 nm or less.

(61) (1) or (37) to (60)
In the information recording medium described in any one of the above, the thickness of the second reflective layer is in a range of 50 nm or more and 250 nm or less.

(62) The information recording medium according to (1) or (37), further comprising an inorganic super-resolution reading layer on the side of the protective layer opposite to the recording film.

(63) The information recording medium according to (1) or (37), further comprising an inorganic super-resolution readout layer at an interface of any of the layers.

(64) The information recording medium according to (1) or (37), further comprising an inorganic super-resolution readout layer between the protective layers.

(65) The information recording medium is characterized in that the information recording medium is provided with a mask layer for super-resolution reading of an inorganic substance formed directly or via an underlayer on the substrate on which the information is recorded by the unevenness.

(66) An information recording thin film, which is formed on a substrate directly or through an underlayer and records and / or reproduces information by an atomic arrangement change caused by irradiation of an energy beam, is a recording film or a super solution. A mask layer for image reading, a reflection layer, and a wavelength of 400
The information recording medium is characterized in that the reflectance in a crystalline state and / or an amorphous state has a minimum value in a range from nm to 800 nm.

(67) An information recording thin film which is formed on a substrate directly or through an underlayer and records and / or reproduces information by a change in atomic arrangement caused by irradiation of an energy beam is provided as a recording film. An information recording medium comprising a reflective layer and having a reflectance of 20% or more between a maximum value and a minimum value in a wavelength range of 400 nm or more and 850 nm or less when light is incident from the recording film side. It is characterized by the following.

(68) An information recording thin film formed on a substrate directly or through an underlayer and recording and / or reproducing information by a change in atomic arrangement caused by irradiation of an energy beam is provided as a recording film. In addition, the information recording medium is provided with a reflective layer, and has a minimum value in a wavelength range of 400 nm or more and 850 nm or less in the reflectance of the reflective layer when light is incident from the recording film side.

(69) The information recording medium according to (1) or (37), wherein the thickness of the land portion of the first reflective layer is formed to be at least 2 nm thicker than the thickness of the groove portion. .

(70) The recording film material is Ag2Ge20
Sb22Te56, Ag5Ge20Sb20Te55, Ag1Ge
21Sb23Te55, etc. Ag-Ge-Sb-Te system.

In the Ag—Ge—Sb—Te system, Ag is 1 to
5 atomic%, Ge 17-23 atomic%, Sb 19-25
It has been found that a composition having an atomic% and a Te in the range of 53 to 59 atomic% hardly causes a decrease in the number of rewritable times. AgSbTe2 or a material close to AgSbTe2
It has been found that a composition in which the balance is 15%, Ge2Sb2Te5, or a material close to Ge2Sb2Te5, is preferable because the difference in reflectance between the crystalline and amorphous states is large, and the reproduced signal is large.

Next, ((Cr4Te5) 10 (Ge2Sb)
2Te5) 90) Cr-Ge-Sb-Te, Co-Ge-
Even in Sb-Te, V-Ge-Sb-Te, etc., the jitter of 30,000 or more rewrites increases, but similar results were obtained in many other characteristics.

Further, Ge2Sb2Te5, G
eSb2Te4, GeSb4Te7, In3SbTe2, In
35Sb32Te33, In31Sb26Te43, GeTe, Ag
-In-Sb-Te, Ni-Ge-Sb-Te, Pt-Ge-S
b-Te, Si-Ge-Sb-Te, Au-Ge-Sb-T
e, Cu-Ge-Sb-Te, Mo-Ge-Sb-Te, Mn
-Ge-Sb-Te, Fe-Ge-Sb-Te, Ti-Ge-S
Even if it is replaced with at least one of b-Te, Bi-Ge-Sb-Te, or a composition close to these, or if a part of Ge is replaced with In, characteristics close to these can be obtained.

Further, a recording film to which a phase change component containing Ge-Sb-Te as a main component and a high melting point component having a higher melting point is added hardly causes a decrease in the number of rewritable times. 95% or more of the total number of atoms of the phase change component is composed of a combination of GeTe and Sb2Te3, and 95% or more of the total number of atoms of the high melting point component is C.
r-Te, Cr-Sb, Cr-Ge, Cr-Sb-T
e, Cr-Sb-Ge, Cr-Ge-Te, Co-T
e, Co-Sb, Co-Ge, Co-Sb-Te, Co
-Sb-Ge, Co-Ge-Te, Cu-Te, Cu
-Sb, Cu-Ge, Cu-Sb-Te, Cu-Sb-
Ge, Cu-Ge-Te, Mn-Te, Mn-Sb,
Mn-Ge, Mn-Sb-Te, Mn-Sb-Ge, M
n-Ge-Te, V-Te, V-Sb, V-Ge, V
-Sb-Te, V-Sb-Ge, V-Ge-Te, Ni
-Te, Ni-Sb, Ni-Ge, Ni-Sb-Te,
Ni-Sb-Ge, Ni-Ge-Te, Mo-Te, M
o-Sb, Mo-Ge, Mo-Sb-Te, Mo-Sb
-Ge, Mo-Ge-Te, W-Te, W-Sb, W-
Ge, W-Sb-Te, W-Sb-Ge, W-Ge-T
e, Ag-Te, Ag-Sb, Ag-Ge, Ag-Sb
When the composition is at least one of -Te, Ag-Sb-Ge, and Ag-Ge-Te, or a composition close to this, the number of rewritable times is less likely to decrease. Cr4Te5, Cr
It has been found that 2Te3, Cr5-Te8, etc., Cr-Te have a particularly low jitter of 100,000 to 10,000 rewrites. Ag2Te, AgSbTe2, etc. have a large signal intensity even when the light source wavelength is short, and Ag-Te, Ag-Sb-T
e was found to be particularly good.

When the composition of 95% or more of the total number of atoms of the phase change component is Ge2Sb2Te5, the proportion of the high melting point component atoms in the total number of atoms of the recording film is 5 atomic% or more and 20 atomic% or less. Good characteristics. If the content is 5 at% or more and 15 at% or less, the erasing characteristics are good, so the rewriting characteristics are better.

When the content of the impurity element in the recording film is 10 atomic% or less of the recording film component, the deterioration of the rewriting characteristics can be reduced.
preferable. More preferably, the content is 5 atomic% or less.

(71) The material of the first protective layer is (Zn
S) 80 (SiO2) 20, a mixture of ZnS and SiO2 at different mixing ratios, Si-N-based material, Si-ON-based material, SiO
2, SiO, TiO2, Al2O3, Y2O3, CeO, La
2O3, In2O3, GeO, GeO2, PbO, SnO,
SnO2, Bi2O3, TeO2, WO2, WO3, Sc2O
3, oxides such as Ta2O5 and ZrO2, TaN, AlN,
Si3N4, Al-Si-N-based materials (for example, AlSiN
2) nitrides such as ZnS, Sb2S3, CdS, In2S
3, sulfides such as Ga2S3, GeS, SnS2, PbS, Bi2S3, SnSe2, Sb2Se3, CdSe, ZnS
e, In2Se3, Ga2Se3, GeSe, GeSe2,
Selenides such as SnSe, PbSe, Bi2Se3, C
Fluoride such as eF3, MgF2, CaF2, or S
It is characterized by comprising i, Ge, TiB2, B4C, B, C or a composition close to the above-mentioned materials, a layer of a mixed material thereof, or a multi-layer thereof. Second protective layer Al2
Alternative materials for O3 are materials based on Al2O3,
SiO2 and a material containing SiO2 as a main component are more preferable because they have a high thermal conductivity and can reduce an increase in jitter which is observed in the vicinity of 10 to 100 rewritings of the trailing edge.

When the protective layer is composed of a plurality of layers, there is a disadvantage that the manufacturing process is complicated, but there is an advantage that the rewriting characteristics can be improved and the recording sensitivity can be improved. When the protective layer is composed of a single first protective layer, there is a disadvantage that any one of the recording sensitivity and the rewriting characteristic is slightly lowered, but there is an advantage that the manufacturing process is simplified.

(72) The intermediate layer material is Al2O3, Al
Oxides whose composition cost of O and O deviated from 2: 3, (Zn
S) 80 (SiO2) 20, a mixture of ZnS and SiO2 at different mixing ratios, Si-N-based material, Si-ON-based material, SiO
2, SiO, TiO2, Al2O3, Y2O3, CeO, La
2O3, In2O3, GeO, GeO2, PbO, SnO,
SnO2, Bi2O3, TeO2, WO2, WO3, Sc2O
3, oxides such as Ta2O5 and ZrO2, TaN, AlN,
Si3N4, Al-Si-N-based materials (for example, AlSiN
2) nitrides such as ZnS, Sb2S3, CdS, In2S
3, sulfides such as Ga2S3, GeS, SnS2, PbS, Bi2S3, SnSe2, Sb2Se3, CdSe, ZnS
e, In2Se3, Ga2Se3, GeSe, GeSe2,
Selenides such as SnSe, PbSe, Bi2Se3, C
Fluoride such as eF3, MgF2, CaF2, or S
It is characterized by being made of i, Ge, TiB2, B4C, B, C or a composition close to the above materials.

(73) The substrate is a polycarbonate substrate having a continuous groove directly on the surface, a chemically strengthened glass having a polyolefin, epoxy, acrylic resin, or ultraviolet curing resin layer formed on the surface. And Further, other than the substrate having the continuous groove servo format, a substrate having a sample servo format, a substrate having another format, or the like may be used. A substrate having a format in which recording and reproduction can be performed on both the groove and the land may be used. 1 disk size
The size is not limited to 2 cm, but may be 13 cm, 3.5 ', 2.5', or another size. The disk thickness is not limited to 0.6 mm, but may be other thicknesses such as 1.2 mm and 0.8 mm.

(74) The first reflective layer material is made of Si, S
i is Au, Ag, Cu, Al, Ni, Fe, Co, C
r, Ti, Pd, Pt, W, Ta, Mo, Sb, Bi,
Dy, Cd, Mn, Mg, V, Zn, Ga, Tl, P
b, C, B, and S are added. In this case, when the content of the additional element is 1 atomic% or more and 25 atomic% or less, the reflectance level hardly fluctuates at the time of rewriting many times.

Further, since the Si—Ge mixed material can make the light absorptance of the recording mark portion smaller than the light absorptance of the portion other than the recording mark, it is possible to prevent the disappearance due to the difference in the light absorptivity, and to reduce the number of rewritable times. Does not drop. When the content of Ge is 10 atomic% or more and 80 atomic% or less, the number of rewritable times hardly decreases.

Next, Si—N, Si—Sn or Si—N
Similar results were obtained with the -In mixed material or a mixed material of two or more of these mixed materials. Even if these reflective layer materials are used not only for the phase change film of the present invention but also for the case where another phase change film is used, the number of rewritable times does not decrease as compared with the conventional reflective layer material. When the content of the element added to Si is 3 atomic% or more and 50 atomic% or less, the number of rewritable times hardly decreases. Further, a layer made of a mixed material containing Si and Ge other than those described above, a material having a large refractive index and a small extinction coefficient may be used, or a multi-layer made of those phases may be used. A composite layer with another substance such as a substance may be used. Ge can also be used. In addition, various nitrides, sulfides, and selenides can also be used.

Further, materials other than those described above, which have a refractive index of 3 or more and an extinction coefficient of 2 or less at a recording wavelength or a reproduction wavelength, can also be used.

It is preferable that Si and the material of the first reflective layer instead of Si be 90% or more of the total number of atoms of the first reflective layer. When the amount of impurities other than the above-mentioned materials became 10 atomic% or more, deterioration of the rewriting characteristics was observed.

(75) The material of the second reflection layer is Al-T
i, an Al-Ag, Al-Cu, Al-Cr, Al-Co alloy such as Al-Co, and a material containing Al as a main component.

In addition, Al alloys other than the above, Au, Ag,
Cu, Al, Ni, Fe, Co, Cr, Ti, Pd, P
t, W, Ta, Mo, Sb, Bi, Dy, Cd, Mn,
Mg, V element simple substance, Au alloy, Ag alloy, Cu
Alloy, Pd alloy, Pt alloy, Sb-Bi, SUS, Ni
-Cr, an alloy containing these as a main component, or a layer made of an alloy of these may be used, a multi-layer made of these layers may be used, or these and other substances such as oxides may be used. Or a composite layer of these with another substance such as another metal.

Among them, Cu, Al, Au, Cu alloy,
A disk having a large thermal conductivity, such as an Al alloy or an Au alloy, has a quenched disk structure, and is unlikely to have a change in reflectance due to rewriting many times. Ag, Ag alloy, and the like have similar characteristics. Also, Sb-Bi, Dy, SU
Those having a small thermal conductivity, such as S and Ni-Cr, have an advantage that the recording sensitivity is improved because the temperature is easily maintained.

Further, when Mo or Mo compound is used, the reactivity is low, and there is no possibility that the characteristics may be degraded by reacting with the first reflective layer by a large number of laser irradiations. There is. Then
Similar results were obtained for W and W compounds.

Further, compared to Au alone, Au-Ag,
Au alloys such as Au-Co and Au-Al are preferred because they have the advantage of increasing the adhesive strength.

As long as the material has a different refractive index and extinction coefficient from the first reflective layer, an alloy mainly containing Si, Ge, Sn, or In, or a layer made of an alloy of these and the above elements may be used. Or a multi-layer of these layers, a composite layer of these with another substance such as an oxide, a composite layer of these with another substance such as another metal, or the like. Good. Further, the extinction coefficient k of the material is preferably 3 or more.

It is preferable that the material of the second reflective layer in place of Al-Ti and Al-Ti is 80% or more of the total number of atoms of the second reflective layer. When the amount of impurities other than the above-mentioned materials became 20 atomic% or more, deterioration of the rewriting characteristics was observed.

The material of the third reflective layer formed between the first reflective layer and the intermediate layer is characterized by using any of the above-mentioned group of materials that can be used for the second reflective layer.

(76) The recording / reproducing characteristics and the like are improved even if the thicknesses and materials of the respective layers are independently set in the respective preferable ranges, but the effect is further improved by combining the respective preferable ranges. And

(77) Regarding the first reflective layer material,
(39)-(40), (43)-(45), (74),
Regarding the second reflective layer material, (39) to (40), (4)
The materials described in 6) to (47) and (75) can be used, but by selecting these combinations, the rewriting characteristics are improved.

[0139] A preferred combination is that at least 90% of the total number of atoms of the first reflective layer is composed of Si, and at least 90% of the total number of atoms of the second reflective layer is Al-T.
i, one of Al-Ag, Al-Cu, Al-Cr, and Al-Co. Further, a component that is 90% or more of the total number of atoms of the first reflective layer is Si, Si-T.
i, Si-Mo, Si-Al, Si-Ge, Ge, and at least 90% of the total number of atoms of the second reflective layer are at least one of Mo and Mo compounds. Or the first reflective layer is made of Si, Si-Ti, Si-Mo, Si-Al, S
at least one of i-Ge and Ge, or a composition close thereto, wherein the second reflective layer is made of Al, Al alloy, Au, A
u alloy, Ag, Ag alloy, Cu, Cu alloy, Pt, Pt
In the case of at least one of an alloy, Mo, a Mo compound, and an Sb-Bi solid solution, or a composition close to this, components of 90% or more of the total number of atoms of the first reflective layer are Si-Ti, Si-M
o, at least one of Si-Al, and 90% or more of the total number of atoms of the second reflective layer is Al-T.
i, Al-Ag, Al-Cu, Al-Cr, and Al-Co.

(78) The mask layer material for high-sensitivity super-resolution reading includes [(SiO 2) 71 (Na 2 O) 14 (Ca
O) 8 (MgO) 6 (Al2O3) 1] 80 [(Co3O4)] 2
0 is preferred. As an alternative material, [(SiO2)
71 (Na2O) 14 (CaO) 8 (MgO) 6 (Al2O3)
Materials having different [(Co3 O4)] ratios with respect to [1] may be used. The more (Co3 O4), the greater the C / N at the time of reading. Further, (Co3 O4) may be a composition such as CoO, Co2 O3, a mixture thereof, or the like in which the ratio of metal to oxygen is different. Further, a transition metal oxide in which Co is replaced by another transition metal element, a mixture thereof, or an oxide having a composition close to this may be used. Of these, Fe oxides and Ni oxides are more preferable because the change in transmittance during laser irradiation is large. Co
Oxides are particularly preferred because of their greater change in transmittance.

On the other hand, the above [(SiO 2) 71 (Na 2 O) 14
(CaO) 8 (MgO) 6 (Al2O3) 1]
2), (Na2O), (CaO), (MgO), (Al2O)
O3) may be replaced with a material having a different composition ratio. In this case, it is more preferable that the SiO2 content be 50% or more of the whole, since the transmittance change during laser irradiation is large. Furthermore, Si
O2, [(SiO2) 72 (Na2O) 16 (CaO) 12 (L
a2O3) 53 (B2O3) 37 (ZrO2) 6 (Ta2O5)
5], B2O3, P2O5, GeO2, As2O3, Li2O-
SiO2, Na2O-SiO2, K2O-SiO2, MgO
-SiO2, CaO-SiO2, BaO-SiO2, Pb
O-SiO2, Na2O-CaO-SiO2, Al2O3-
SiO2, Li2O-B2O3, Na2O-B2O3, K2O-
B2O3, MgO-B2O3, CaO-B2O3, PbO-
B2O3, Na2O-CaO-B2O3, ZnO-PbO-
B2O3, Al2O3-B2O3, SiO2-B2O3, Li2O
-P2O5, Na2O-P2O5, MgO-P2O5, CaO
-P2O5, BaO-P2O5, ZnO-BaO-P2O5,
Al2O3-P2O5, SiO2-P2O5, B2O3-P2O
5, V2O5-P2O5, Fe2O3-P2O5, WO3-P2O
5, Li2O-GeO2, Na2O-GeO2, K2O-G
eO2, B2O3-GeO2, SiO2-GeO2, Na2O
-WO3, K2O-WO3, Na2O-MoO3, K2O-M
oO3, Li2O-MoO3, Na2O-TeO2, Na2O
-B2O3-SiO2, Na2O-Al2O3-SiO2, C
aO-Al2O3-SiO2, Na2O-Al2O3-B2O3
-SiO2, BeF2, NaF-BeF2, ZrF4-Ba
F2-ThF4, GdF3-BaF2-ZrF4, Al (P
Similar characteristics can be obtained by changing to a material having a composition close to O3) -AlF3-NaF-CaF2, inorganic glass, or a mixture thereof.

In addition, it is preferable to add a rare earth element or oxide and optimize the amount, because the apparent spot diameter can be optimized by narrowing it. The addition amount is preferably 1 atomic% or more and 30% or less.

(79) The high-sensitivity super-resolution read mask layer is formed by sputtering. This may be formed into a film by vacuum evaporation.

These sputter sources or vapor deposition sources are preferably made of a target or a vapor deposition base material having a composition close to the composition of the high-sensitivity super-resolution readout mask layer. In addition, similar characteristics can be obtained even when a film is formed from a plurality of targets or deposition base materials having different compositions. In addition to using a target having a composition close to the composition of the mask layer for high-sensitivity super-resolution reading, a target in which chips having different compositions are attached to one target may be used. In this case, the composition stability in performing a large number of sputterings is low, but there is an advantage that the composition adjustment is simple.

In addition, it is preferable to use a mask as described below to prepare a place where a high-sensitivity super-resolution readout mask layer is not formed on an area where laser light is focused during recording / reproduction.

(80) The reflective layer material of the information recording medium having the high-sensitivity super-resolution readout mask layer is Al.
97Ti3 film, Al-Ti, Al-Ag, Al-Cu, Al
A material mainly composed of an Al alloy such as -Cr or Al-Co is preferable. Al can also be used. Since the Al alloy is soft, there is an advantage that interfacial peeling or the like due to internal stress does not easily occur.

In the case of an Al alloy, the reflectivity can be increased when the Al content is 50 atomic% or more and 99.9 atomic% or less.
N is good.

In addition, other Al alloys, Au, Ag,
Cu, Al, Ni, Fe, Co, Cr, Ti, Pd, P
t, W, Ta, Mo, Sb, Bi, Dy, Cd, Mn,
Mg, V element simple substance, Au alloy, Ag alloy, Cu
Alloys, Pd alloys, Pt alloys, Sb-Bi, SUS (stainless steel), Ni-Cr, and other alloys containing these as main components, or layers composed of alloys of these alloys may be used. May be used, a composite layer of these with another substance such as an oxide, a composite layer of these with another substance such as another metal, or the like may be used. This has a similar effect.

[0149] Compared to Au alone, Au-Ag, A
Au alloys such as u-Co and Au-Al are preferred because they have the advantage of increasing the adhesive strength.

In addition, any material having a reflectance of 40% or more may be used. The extinction coefficient k of the material is preferably 3 or more.

The thickness of the reflective layer is at least 30 nm from the point of increasing the reflectance, and is 200 nm from the point of reducing the production time.
The following is more preferred. More preferably, the thickness is 50 nm to 100 nm.

[0152]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the following examples. In the present invention, a plurality of thin films are laminated,
Although the structure takes advantage of the characteristics of each thin film, each layer does not necessarily have to be strictly separated.
If it is about m or less, the composition ratio near the boundary between the layers may be continuously changed. Further, in the present invention, the composition of each film is represented by atomic%.

Example 1 A groove having a width of 0.74 μm and a depth of 0.07 μm was 1.48.
FIG. 1 shows a land / groove recording polycarbonate substrate having a thickness of 0.6 mm provided at a pitch of μm and having address information for recording information on both lands and grooves provided at the head of each sector. Thin film (first protective layer: (ZnS) 80 (SiO2) 20 (80 nm), recording layer: A
g2.5 Ge21 Sb21 Te55.5 phase change recording layer (20 n
m), second protective layer: (ZnS) 80 (SiO2) 20 (20 nm), first reflective layer: Al75Cr25 (140 nm), second reflective layer: Al97
Ti3 (140 nm)) was sequentially formed by a sputtering process. Further, an ultraviolet curable resin was applied as an organic protective layer on the second reflective layer by a spin coating method of about 10 μm, and was cured by ultraviolet light. The two phase-change optical disks prepared in this manner were bonded together on the surface to which an ultraviolet curable resin was applied.

There are 24 zones for user recording in the radial direction of this disc, and 17 to 40 in one circumference of the zone.
There are sectors. As a motor control method for performing recording / reproduction, a ZCLV (Zone Constant) that changes the number of rotations of the disk for each zone in which recording / reproduction is performed.
Lenear Velocity) method. In this format, the innermost and outermost disks in each zone have different disk linear velocities, and the innermost and outermost disk linear velocities are 6.0 m / s and 6.35 m / s, respectively. .

An information recording / reproducing system was constituted by the disc and the information recording / reproducing apparatus shown in FIG. 2 to record information. The operation of the information recording / reproducing system will be described below.

Information from outside the recording apparatus is transmitted to the 8-16 modulator in units of 8 bits. When recording information on the disk 1, recording was performed using a modulation method for converting 8 bits of information into 16 bits, that is, a so-called 8-16 modulation method. In this modulation method, information having a mark length of 3T to 11T corresponding to 8-bit information is recorded on a medium. The 8-16 modulator 8 in the figure performs this modulation. Here, T represents a clock cycle at the time of information recording, and here is set to 34.2 ns.

3T-1 converted by the 8-16 modulator
The 4T digital signal is transferred to the recording waveform generating circuit 6, where the width of the high power pulse is set to about T / 2, and the low power level laser irradiation having a width of about T / 2 is performed between the high power level laser irradiations. A multi-pulse recording waveform is generated in which laser irradiation at an intermediate power level is performed between the series of high power pulses. At this time, the high power level for forming the recording mark was 11.0 mW, the intermediate power level at which the recording mark could be erased was 4.5 mW, and the low power level lower than the intermediate power level was 0.5 mW.

The recording waveform generated by the recording waveform generating circuit 6 is transferred to the laser driving circuit 7, and the laser driving circuit 7 causes the semiconductor laser in the optical head 3 to emit light based on the recording waveform.

The optical head 3 mounted on the recording apparatus includes:
Light wavelength 650 nm as energy beam for information recording
Semiconductor laser is used. The laser light was focused on the recording layer of the disk 1 with an objective lens having a lens NA of 0.6, and a laser beam having an energy corresponding to the recording waveform was applied to record information. At this time, the diameter of the laser beam is about 1
Microns and the laser beam was polarized circularly.

The present recording apparatus is compatible with a method of recording information on both grooves and lands (areas between grooves) (so-called land-groove recording method). In this recording apparatus, the tracking for the land and the groove can be arbitrarily selected by the L / G servo circuit 9.

Reproduction of recorded information was also performed using the optical head 3. By irradiating the laser beam narrowed down to the same size as at the time of recording on the recorded mark and detecting the reflected light from the mark and the part other than the mark,
Obtain a playback signal. The amplitude of the reproduced signal is increased by the preamplifier circuit 4 and transferred to the 8-16 demodulator 10. 8
The -16 demodulator 10 converts every 16 bits into 8-bit information. With the above operation, the reproduction of the recorded mark is completed.

When recording on the optical disc 1 under the above conditions, the mark length of the shortest mark 3T is about 0.62 μm, and the mark length of the longest mark 14T is about 3.08 μm.

The crystallization rate of the recording layer was adjusted so that the portion irradiated with the high power laser pulse having the multi-pulse waveform became amorphous, and the portion irradiated with the intermediate power laser beam became crystalline. I have.

The optical disk 1 had a reflectivity of 17% when reproduced by the recording / reproducing apparatus. Also,
The voltage level when the reflected light reproduced from the 14T mark is converted into a voltage by the photoelectric conversion element in the optical head 3 is V1.
4. (V0-V14) / V0 where V0 is the voltage level when the reflected light from the area where the recording mark is not recorded (crystal state) is converted to a voltage by the photoelectric conversion element, and As will be described, when the recording / reproduction is performed on the optical disk 1 under the above conditions, the reproduction signal modulation degree is 60%.

As described in detail above, by combining the above-mentioned information recording / reproducing apparatus with the information recording medium of the present invention, high-density recording is possible, and a reproduced signal of good quality is obtained. An information recording / reproducing system capable of reproducing an optical disc is realized. In the above embodiment, the case where the crystal region has a higher reflectance than the recording mark region (amorphous region) has been described. However, it is not necessary that the crystal region has a higher reflectance than the recording mark region. Even if the recording mark has a higher reflectance than the crystal area, it does not matter. In this case, the reproduction signal modulation degree is set to (V14-V0) / V
14, the value may be 50% or more, and the reflectance of the reflected light reproduced from the 14T mark may be designed to be 15% or more.

In the following examples, information was recorded and reproduced by an information recording and reproducing system using the above information recording and reproducing apparatus.

Example 2 Co was used as an additive element in the first reflection layer of the optical disc 1 described above.
The reflectance and the laser power (recording power) required for recording when the recording layer was in a crystalline state were measured. When the amount of Co added is lower than 5%, a sufficiently large reproduction signal modulation degree can be obtained, but the recording power becomes 13 mW or more, which is not practical. When the Co content is 35% or more,
Although a sufficiently low recording power of 9 mW or less was obtained, the degree of modulation of the reproduction signal was 50% or less, and practical reproduction signal quality could not be obtained. When the amount of Co added was 5% or more and 35% or less, practical values such as a recording power of 13 mW or less and a reproduction signal modulation degree of 50% or more could be obtained. At this time, the reflectance from the crystalline state showed a good value of 15 to 24%. In addition, Ti other than Co as an additional element,
Cr, Ni, Mg, Si, V, Ca, Fe, Zn, Z
r, Nb, Mo, Rh, Sn, Sb, Te, Ta, W,
Similar results were obtained for Ir, Pb, B and C. In particular, when the additive element was Co, Cr, Ti, Ni, Fe, or Cu, a great effect was obtained. A great effect is exhibited when the Al content is 65 to 95% irrespective of the added element. Particularly, when the Al content is 70 to 80%, the recording sensitivity is good and a large degree of modulation is obtained. .

[0168] In addition to Al, the above-mentioned elements were added to high reflectivity metals such as Cu, Ag, Pt, and Pd, but the same effect was obtained.
In particular, Al and Au have high reliability of the reproduction signal quality after the corrosion resistance test and at the time of rewriting many times, and are excellent as the first reflection layer.

Further, although not as high as the above-mentioned high reflectance metal, C
Since o, Ni, and the like also have relatively high reflectance, an optical disk having high reflectance, high modulation degree, and high recording sensitivity may be realized by containing the above-mentioned additional element.

Further, in the optical disk of the present invention, the presence of the first reflective layer makes it difficult for heat generated in the recording layer during recording to spread in the plane direction of the recording layer. It tends to flow easily to the reflective layer. For this reason, it is possible to suppress thermal interference between marks that occurs during laser beam irradiation, which is a problem during mark edge recording,
A high quality signal with low jitter can be obtained.

Example 3 The additive element of the second reflective layer of the optical disc 1 was Cu,
The jitter of the reproduced signal when the recording layer was in a crystalline state was measured. When the Al content was lower than 90%, the reproduced signal had a jitter value of 10% or more, which was not a practical value. However, when the Al content was 90% or more, a good jitter of 10% or less was obtained. Value was obtained. At this time, favorable values were obtained, such as a reflectivity from the crystalline state of 17%, a reproduction signal modulation degree of 65%, and a recording power of 13 mW or less. In addition, Ti, Cr, Ni, other than Co,
Mg, Si, V, Ca, Fe, Zn, Zr, Nb, M
o, Rh, Sn, Sb, Te, Ta, W, Ir, Pb,
Similar results were obtained for B and C. In particular, when the additive element was Co, Cr, Ti, Ni, Fe, or Cu, a great effect was obtained. A large effect is exhibited when the Al content is 90% or more regardless of the added element.
%, The recording sensitivity was good and a sufficiently low jitter value was obtained.

[0172] In addition to Al, the above-mentioned elements were added to high thermal conductivity metals such as Cu, Ag, Pt, Pd, and Mo, but the same effect was obtained. In particular, Al, Au, and Mo have high reliability of the reproduction signal quality after the corrosion resistance test and at the time of rewriting many times, and are excellent as the second reflection layer.

Although not as high as the above-mentioned high thermal conductivity metal,
Co, Ni and the like also have a relatively high reflectance, and an optical disk having a high reflectance, a high degree of modulation, and a high recording sensitivity may be realized by containing the above-mentioned additional element.

In the optical disk of the present invention, the presence of the second reflective layer allows the heat generated in the recording layer during recording to be selectively transferred from the first reflective layer without being stored in the first reflective layer. It tends to flow to the second reflective layer. For this reason, it is possible to suppress thermal interference between marks that occurs during laser beam irradiation, which is a problem during mark edge recording,
Moreover, since the recording layer can be rapidly cooled, problems such as flow of the recording film after rewriting many times hardly occur. Therefore, a high quality signal with low jitter can be obtained.

In this embodiment, Ge is used as the optical disk.
Although recording is performed on a phase change recording layer mainly containing Sb, Te, In, Ag, etc., the principle of the present invention is that heat is generated by an energy beam, and the heat is used to record a recording mark. Along with the optical properties (reflectance, modulation) of
It is intended to control the thermal characteristics (temperature distribution, cooling rate distribution), so it is not particularly limited to the phase change optical disk, and may be used for the magneto-optical recording layer mainly containing Tb, Fe, Co, Dy, Gd, etc. It is also effective in recording. The invention is not limited to a rewritable information recording medium. In addition, in the case of organic dye recording in which recording is performed by changing the shape of the substrate or the recording layer, only when a high-power laser beam is irradiated, a change occurs, and this change is irreversible. The principle of the present invention is to control heat characteristics (temperature distribution, cooling rate distribution) as well as optical characteristics (reflectance, modulation degree) of an optical disk on which recording marks are recorded by the heat generated by the energy beam. Is not particularly limited to rewritable optical discs,
It can also be applied to a write-once optical disc.

Embodiment 4 In the optical disc of the present invention, there are regions suitable for the thicknesses of the first reflection layer and the second reflection layer. If the first reflective layer is too thin, problems such as a decrease in recording sensitivity and an increase in jitter due to unerased recording marks may occur. If the first reflective layer is too thick, the productivity may decrease, and the recording mark shape may fluctuate. (Effects of generated coarse crystal grains) causes a problem such as an increase in jitter. Also, if the second reflective layer is too thin, problems such as recording mark shape fluctuation jitter increase and recording film flow will occur. If the second reflective layer is too thick, problems such as a decrease in recording sensitivity and an increase in jitter due to remaining disappearance will occur. The composition of the first reflective layer
An experiment was conducted with the composition of Al77Cr23 and the second reflective layer being Al95Cu5, and the relationship between the thickness of the first reflective layer and the reproduction signal jitter was determined.

When the thickness of the first reflective layer is thinner than 30 nm or thicker than 300 nm, the jitter value increases and a practical jitter value of 10% or less could not be obtained. When the thickness is 300 nm or less, a good jitter of 10% or less can be obtained. At this time, the reflectivity, the reproduction signal modulation degree, and the recording power showed good values of 20%, 65%, and 9.5 to 12.5 mW, respectively.

Further, the dependency of the reproduction signal jitter and the recording power of the optical disc of the present invention after 100,000 rewritings was measured for the thickness of the second reflective layer. At this time, the composition of the first reflection layer was changed to Al77.
The composition of Ni28 and the second reflective layer was Mo.

When the film thickness of the second reflective layer was less than 50 nm, a good recording power of 9.5 mW or less could be obtained, but the reproduction signal jitter after 100,000 rewrites was 10
%, Which was not practical. On the other hand, the second
When the thickness of the reflective layer was greater than 250 nm, the reproduction signal jitter after rewriting 100,000 times was as good as 8% or less, but the recording power was 13 mW or more, which was not a practical value. When the thickness of the second reflective layer was 50 nm or more and 250 nm or less, both a good jitter value of 10% or less and a high recording sensitivity of 13 mW or less could be achieved. At this time, the reflectance, the modulation degree of the reproduction signal, and the recording power are 15
% And 55%. Further, by using Mo for the second reflection layer, the flow of the recording film was significantly suppressed.

Embodiment 5 In the optical disc of the present invention, the reflectance of the first reflection layer is Al, C
Since there is a tendency that the thickness of the first protective layer, the intermediate layer, and the recording layer is 15% or more, the thickness of the first protective layer, the intermediate layer, and the recording layer is higher than that of the high reflectivity metal such as u, Au, Ag, Pt, and Pd. In order to achieve a signal modulation degree of 50% or more, it is necessary to control to an appropriate region. The first protective layer may have a wavelength of λ / (3n) to λ / (6n), where λ is the laser wavelength and n is the refractive index of the first protective layer. By doing so, laser light interferes between the surface of the recording layer and the surface of the transparent substrate, and a high reproduction signal modulation degree can be obtained.

The first protective layer may be made of an oxide, a low oxide, a sulfide, a nitride having a refractive index of 1.5 or more, or a semiconductor such as Si having a small absorptance.
iO2, In2O3, Al2O3, GeO, GeO2, PbO, SnO, SnO2, Bi2O
3, TeO2, WO2, WO3, Ta2O5, TiO2, ZrO2, CdS, ZnS, Cd
Se, ZnSe, In2S3, InSe3, Sb2S3, Sb2Se3, Ga2S3, Ga2S
e3, MgF2, GeS, GeSe, GeSe2, SnS, SnSe, PbS, PbSe,
It is preferable that the composition has a composition close to at least one of Bi2S3, Bi2Se3, TaN, Si3N4, AlN, and Si or a mixture of two or more of them. Generally, a film thickness of at least about 50 nm is required in order to prevent mechanical strength or chemical change of the recording layer and moisture penetrating from the polycarbonate substrate.

If the thickness of the first protective layer is too thick, the laser light interference condition is deviated, so the upper limit is about 100 nm. Particularly, the thickness of the first protective layer is 70 to 90 n.
In the case of m, the condition that the reflectance is 15% or more and the reproduction signal modulation degree is 50% or more can be satisfied, sufficient mechanical strength can be obtained, and moisture permeating from the polycarbonate substrate and chemical change of the recording layer can be prevented. it can. In particular, recording layer flow occurs due to multiple recordings such as a phase-change recording layer,
In the case where the reproduction signal is degraded, the flow of the recording film can be suppressed by setting the thickness of the first protective layer to 70 to 90 nm.

Optically, the thickness of the recording layer is
10 nm or more and 30 nm or less are suitable. In particular, when the thickness of the recording layer is 15 nm or more and 25 nm or less, the reflectance is 1
5% or more, and the reproduction signal modulation degree can be 50% or more. However, in a recording layer such as a phase-change recording layer in which a reproduction signal deteriorates due to a recording film flow, when the recording layer is 25 nm or less, the strength of the recording layer is weak and easily deteriorates. The first reflective layer used in the present invention has a smaller coefficient of thermal expansion than a normal high-reflectivity metal, and therefore is excellent in strength and has a recording layer thickness of 25.
Even when the thickness is less than nm, the flow of the recording film can be suppressed.

As the substance that can be used for the intermediate layer, the same substance as that for the first protective layer can be used. Optically, it is required to be as thin as possible. However, in order to facilitate the reaction between the recording layer and the first reflective layer or to heat the recording layer, 10 n
m or more and 40 nm or less is suitable. Especially 15 nm or more 3
When it is 0 nm or less, good thermal characteristics and optical characteristics can be obtained.

In the above description, the first protective layer, the intermediate layer,
Although the case where the recording layer is constituted by a single layer has been described, the important point is that the transparent substrate positioned on the light incident side of the recording layer and the recording layer satisfy the above-described laser light interference condition. That is, a protective layer having a thickness of 50 nm or more and 100 nm or less is provided. Even if a second protective layer having a composition different from that of the first protective layer is present adjacent to the first protective layer, it does not matter. In particular, when a second protective layer is present between the first protective layer and the recording layer, and a compound of Al and O is added to the second protective layer, a change in reflectivity due to multiple rewriting or a reproduction signal modulation. The degree change can be suppressed. In addition, the recording layer and the intermediate layer do not need to be particularly constituted by a single layer, and may be constituted by a plurality of layers having different compositions.

Embodiment 6 In the optical disc of the present invention, between the intermediate layer and the first reflection layer,
By providing a third reflective layer having a higher content of a high reflectivity metal such as Al, Cu, Ag, Au, Pt, and Pd than the first reflective layer,
Further, both the reflectance and the modulation degree of the reproduced signal are improved (FIG. 3). However, there is an appropriate region in the thickness of the third reflective layer. If the third reflective layer is too thick, problems such as an increase in jitter and a decrease in recording sensitivity occur.

Therefore, the dependency of the recording power and the modulation degree of the reproduction signal of the optical disk of the present invention on the thickness of the third reflective layer was measured.
At this time, the composition of the first reflective layer was Al71Co29, the composition of the second reflective layer was Al98Ti2, and the composition of the third reflective layer was Al98Ti2.

When the film thickness of the third reflective layer was larger than 30 nm, the recording power increased, and recording could not be performed with a practical value of 13 mW or less.
In the case of 0 nm or less, recording could be performed with a recording power of 13 mW or less. At this time, the reproduction signal modulation degree is the third
The value increased with the thickness of the reflective layer, and reached about 70% when the thickness of the third reflective layer was 30 nm. At this time, the reflectivity was as good as 17%.

Embodiment 7 In the optical disc of the present invention, the following metal (semiconductor) oxides, low oxides, sulfides, nitrides, and semiconductors such as Si are provided between the first reflection layer and the second reflection layer. , For example, SiO, SiO2, I
n2O3, Al2O3, GeO, GeO2, PbO, SnO, SnO2, Bi2O3, TeO
2, WO2, WO3, Ta2O5, TiO2, ZrO2, CdS, ZnS, CdSe, Zn
Se, In2S3, InSe3, Sb2S3, Sb2Se3, Ga2S3, Ga2Se3, Mg
F2, GeS, GeSe, GeSe2, SnS, SnSe, PbS, PbSe, Bi2S
3. By laminating an intermediate layer containing at least one of Bi2Se3, TaN, Si3N4, AlN, and Si, it is possible to suppress recording film flow, improve recording sensitivity, and reduce jitter (FIG. 4). ). Further, as the intermediate layer, a material obtained by adding a semiconductor such as an oxide, a low oxide, a sulfide, a nitride, or Si to a metal may be used. A necessary condition for the intermediate layer of the present invention is that the thermal conductivity is at least smaller than that of the second reflective layer. Further, it is desirable that the size be smaller than the first reflection layer. When an intermediate layer is provided between the first reflection layer and the second reflection layer, the optimum thickness of the first reflection layer is 30.
nm or more and 100 nm or less. If the thickness is smaller than 30 nm, the first reflection layer transmits laser light, and the optical properties (refractive index and film thickness) of the intermediate layer undesirably affect the reproduction signal. When the thickness is larger than 100 nm,
The cooling rate of the recording layer is excessively reduced, and the recording layer is deteriorated and the shape of the recording mark is distorted due to recrystallization. When the thickness of the first reflective layer is 50 nm or more and 80 nm or less, a particularly large effect is exhibited.

There is an appropriate value for the thickness of the intermediate layer. When the thickness of the intermediate layer is larger than 200 nm, the recording sensitivity is good, but the jitter of the reproduced signal is greatly increased due to the influence of coarse crystal grains generated around the recording mark. When the thickness of the intermediate layer was 200 nm or less, the jitter of the reproduced signal was 10% or less, which is a practical level. Further, the thickness of the intermediate layer is 50 nm or more and 100 nm or more.
In the following cases, the recording film flow peculiar to the phase change recording film was suppressed, and a good jitter value and the effect of suppressing the recording film flow appeared even after rewriting 100,000 times.

Embodiment 8 When recording video information compressed by an image compression method such as MPEG2 on the information recording medium of the present invention, or at an information transfer rate equivalent to the information transfer rate required for recording the video information Or the information recording / reproducing system of the present invention is designed to record video information compressed by an image compression method such as MPEG2, or the information transfer rate required for recording the video information. When recording is performed at the same information transfer rate, or when a reproduction-only optical disc on which a video compressed by such a compression method is recorded is designed to be reproduced, an optimal area for the composition of the recording layer is obtained. Exists. The reason will be described below.

Normally, when information is reproduced from a read-only optical disk recorded by a video compression system such as MPEG2, or when video information is compressed by a video compression system such as MPEG2 and recorded on an information recording medium, There is an appropriate value for the data transfer rate (information transfer rate) during information recording. For example, the data transfer rate of video information compressed by MPEG2 is about 6 Mb / s, and information of such a transfer rate is recorded on the information recording medium of the present invention. Or, when reproducing, it is necessary to record and reproduce at a disk linear velocity of 3 to 12 m / s. If the disk linear velocity is lower than this, it becomes impossible to record and reproduce video information in real time. If the disk linear velocity is higher than this, video information that is continuously transferred cannot be processed at high speed. It is because.

Further, the recording layer of the phase change recording system has an optimum composition corresponding to the structure of the information recording medium and the linear velocity of the disk. When the information recording medium of the present invention is used, a general information recording medium without the first reflection layer is present between the intermediate layer and the second reflection layer because the first reflection layer having a relatively small thermal conductivity exists between the intermediate layer and the second reflection layer. A recording layer having a composition in a range different from that described above is effective.

As a result of earnest study, the linear velocity of the disk was set to 3 to 1
When recording information on the information recording medium of the present invention so that the shortest mark length is 0.2 to 0.7 μm, at least Ge, Sb, and Te are used as main components, and Ge, Sb, and
Te, Ag, In, Co, Se, Ti, Cr, Ni, M
g, Si, V, Ca, Fe, Zn, Zr, Nb, Mo,
An additive element M comprising at least one element selected from the group consisting of Rh, Sn, Ta, W, Ir, Pb, B and C is added, and the composition ratio is (Ge2Sb2Te5) (1-
x) + Mx (provided that 0.015 <x <0.20) was found to be suitable.

Here, M does not necessarily have to indicate a single element and may be composed of a plurality of elements. What is important here is that one or more of the above-mentioned additional elements are added to the compound having the Ge2Sb2Te5 composition, and the sum of the composition ratios of the above-mentioned additional elements is 1.5% or more and 10% or less. If the sum of the composition ratios of the above-mentioned additional elements is smaller than 1.5%, a recrystallized (coarse-crystallized) region which causes an increase in noise around the recording mark becomes large.
When the sum of the above-mentioned additional elements is more than 10%, erasing (crystallization) of the recording mark becomes impossible (erasing remains), and information is superimposed. Since writing (overwriting) cannot be performed, the reproduction signal jitter greatly increases. When the sum of the composition ratios of the added elements is 1.5% or more and 10% or less, noise rise due to recrystallization around the recording mark and jitter rise due to remaining disappearance do not occur, and good recording / reproduction is realized.

Embodiment 9 In the optical disc of the present invention, the reflectance of the first reflection layer is Al, C
Since there is a tendency that the thickness of the first protective layer, the intermediate layer, and the recording layer is 15% or more, the thickness of the first protective layer, the intermediate layer, and the recording layer is higher than that of the high reflectivity metal such as u, Au, Ag, Pt, and Pd. In order to achieve a signal modulation degree of 50% or more, it is necessary to control to an appropriate region. The first protective layer may have a wavelength of λ / (3n) to λ / (6n), where λ is the laser wavelength and n is the refractive index of the first protective layer. By doing so, laser light interferes between the surface of the recording layer and the surface of the transparent substrate, and a high reproduction signal modulation degree can be obtained.

The first protective layer can be made of an oxide, a low oxide, a sulfide, a nitride having a refractive index of 1.5 or more, or a semiconductor such as Si having a small absorptance.
iO2, In2O3, Al2O3, GeO, GeO2, PbO, SnO, SnO2, Bi2O
3, TeO2, WO2, WO3, Ta2O5, TiO2, ZrO2, CdS, ZnS, Cd
Se, ZnSe, In2S3, InSe3, Sb2S3, Sb2Se3, Ga2S3, Ga2S
e3, MgF2, GeS, GeSe, GeSe2, SnS, SnSe, PbS, PbSe,
It is preferable that the composition has a composition close to at least one of Bi2S3, Bi2Se3, TaN, Si3N4, AlN, and Si or a mixture of two or more of them. Generally, a film thickness of at least about 50 nm is required in order to prevent mechanical strength or chemical change of the recording layer and moisture penetrating from the polycarbonate substrate.

If the thickness of the first protective layer is too large, the condition for interference of the laser light is deviated from the above condition. Therefore, the upper limit is about 100 nm. Particularly, the thickness of the first protective layer is 70 to 90 n.
In the case of m, the condition that the reflectance is 15% or more and the reproduction signal modulation degree is 50% or more can be satisfied, sufficient mechanical strength can be obtained, and moisture permeating from the polycarbonate substrate and chemical change of the recording layer can be prevented. it can. In particular, recording layer flow occurs due to multiple recordings such as a phase-change recording layer,
In the case where the reproduction signal is degraded, the flow of the recording film can be suppressed by setting the thickness of the first protective layer to 70 to 90 nm.

Optically, the thickness of the recording layer is
10 nm or more and 30 nm or less are suitable. In particular, when the thickness of the recording layer is 15 nm or more and 25 nm or less, the reflectance is 1
5% or more, and the reproduction signal modulation degree can be 50% or more. However, in a recording layer such as a phase-change recording layer in which a reproduction signal deteriorates due to a recording film flow, when the recording layer is 25 nm or less, the strength of the recording layer is weak and easily deteriorates. The first reflective layer used in the present invention has a smaller coefficient of thermal expansion than a normal high-reflectivity metal, and therefore is excellent in strength and has a recording layer thickness of 25.
Even when the thickness is less than nm, the flow of the recording film can be suppressed.

As the substance that can be used for the intermediate layer, the same substance as that for the first protective layer can be used. Optically, it is required to be as thin as possible. However, in order to facilitate the reaction between the recording layer and the first reflective layer or to heat the recording layer, 10 n
m or more and 40 nm or less is suitable. Especially 15 nm or more 3
When it is 0 nm or less, good thermal characteristics and optical characteristics can be obtained.

In the above description, the first protective layer, the intermediate layer,
Although the case where the recording layer is constituted by a single layer has been described, the important point is that the transparent substrate positioned on the light incident side of the recording layer and the recording layer satisfy the above-described laser light interference condition. That is, a protective layer having a thickness of 50 nm or more and 100 nm or less is provided. Even if a second protective layer having a composition different from that of the first protective layer is present adjacent to the first protective layer, it does not matter. In particular, when a second protective layer is present between the first protective layer and the recording layer, and a compound of Al and O is added to the second protective layer, a change in reflectivity due to multiple rewriting or a reproduction signal modulation. The degree change can be suppressed.

In this embodiment, the first protective layer 2 is made of (ZnS)
₈₀ (SiO ₂ ) ₂₀ (molar ratio)
Instead, recording sensitivity and jitter will be slightly worse,
What changed the mixing ratio of ZnS and SiO ₂ (SiO ₂ is 15
２０20 mol%), ZnS and the following oxides 10 to 40 mol%
Are preferred. The oxides to be mixed are SiO ₂ , SiO, TiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , C
_{eO, La 2 O 3, In} 2 O 3, GeO, GeO 2, PbO,
SnO, SnO ₂ , Bi ₂ O ₃ , TeO ₂ , WO ₂ , WO ₃ ,
Sc ₂ O ₃ , Ta ₂ O ₅ and ZrO ₂ are preferred. S
i-O-N-based material, Si-Al-O-N-based material, Cr ₂
O _3, Cr-O-based material, such as, oxides such as CoO material such as _{Co 2 O 3, CoO, TaN} , AlN, Si 3 N 4
Such as Si-N-based materials, Al-Si-N-based materials (eg, AlSiN ₂ ),
Nitride such as Ge—N based material, ZnS, Sb ₂ S ₃ , Cd
S, In ₂ S ₃ , Ga ₂ S ₃ , GeS, SnS ₂ , PbS, B
sulfides such as i ₂ S ₃ , SnSe ₃ , Sb ₂ S ₃ , Cd
Se, ZnSe, In ₂ Se ₃ , Ga ₂ Se ₃ , GeS
e, GeSe ₂ , SnSe, PbSe, Bi ₂ Se ₃ and other selenides; CeF ₃ , MgF ₂ and CaF ₂ and other fluorides; Good. Further, a layer of these mixed materials may be used. Further, as in this embodiment, a multi-layered protective layer in which a protective layer made of ZnS and an oxide and a second protective layer of the above-mentioned material having different components are stacked may be used. In this case, among materials other than the above-mentioned material composed of ZnS and oxide, any one of oxide, nitride, and fluoride is more preferable.

In addition to the above, as a material instead of Al ₂ O ₃ of the second protective layer, a material mainly composed of Al ₂ O ₃ , Si 2
A material containing O ₂ or SiO ₂ as a main component is more preferable because it can reduce a rise in jitter which is observed in the vicinity of the number of times of rewriting of the trailing edge of 10 to 100 times.

The effect of the second protective layer is to prevent the reflectance from being changed by multiple overwrites due to the mutual diffusion of the material of the first protective layer and the material of the recording film. If less than 2 nm, the effect was small. Above 2 nm, the change in reflectance can be suppressed to 3% or less of the practical level.
Then, the change in reflectance was 2%. At a film thickness larger than that, the change in reflectance is not much different from that at 4 nm. However, the thermal conductivity of the material of the second protective layer is higher than that of (ZnS) ₈₀ (SiO ₂ ) _20. Exceeds 10%, and when it exceeds 20 nm, the decrease in recording sensitivity exceeds 15%. Therefore, the thickness of the second protective layer is preferably in the range of 2 nm to 20 nm, and particularly preferably in the range of 4 nm to 8 nm. Such a two-layer protective layer has a structure in which the first reflective layer of the present invention is not provided, the first reflective layer is made of Si, and furthermore, 50% or more of read light is transmitted between the substrate and the first protective layer. Even in a laminated structure other than this example, such as a laminated structure in which another layer is added, such as a laminated structure in which a reflective layer thin enough to be added, the adverse effect due to the diffusion of the first protective layer material into the recording film is prevented. It has the effect of doing.

A second material made of any material which can be used also for the second protective layer between the recording film and the intermediate layer.
The effect was further enhanced by providing an intermediate layer. The film thickness was the same as that of the second protective layer.

Further, the recording layer and the intermediate layer do not need to be particularly constituted by a single layer, but may be constituted by a plurality of layers having different compositions.

Embodiment 10 (Structure, Manufacturing Method) FIG. 5 is a sectional structural view of a disc-shaped information recording medium according to an embodiment of the present invention. This medium was manufactured as follows.

First, (ZnS) was deposited on a polycarbonate substrate 11 having a diameter of 12 cm, a thickness of 0.6 mm, and pits indicating addresses and the like on its surface and tracking grooves.
The first protective layer 2 consisting of 80 (SiO2) 20 film is
nm. Next, a second protective layer 13 made of an Al2O3 film
With a film thickness of about 5 nm and an Ag2Ge20Sb22Te56 recording film 14
The intermediate layer 15 made of a (ZnS) 80 (SiO2) 20 film having a thickness of about 20 nm and the first
The reflective layer 16 was formed to have a thickness of about 90 nm, and the second reflective layer 17 made of an Al97Ti3 film was formed to have a thickness of about 200 nm.
The formation of the laminated film was performed by a magnetron sputtering apparatus. Further, a protective coating layer 18 of an ultraviolet curable resin was formed thereon. Thus, a first disk member was obtained.

On the other hand, a second disk member having the same configuration as the first disk member was obtained in exactly the same manner.

Thereafter, the first disk member and the second disk member are respectively provided with the respective protective coating layers 1.
8 and 18 'were bonded together via an adhesive layer 19 to obtain a disc-shaped information recording medium shown in FIG.

For comparison, FIG. 6 is a structural sectional view of a disk-shaped information recording medium having a conventional structure. This medium has the same manufacturing method, except that the film structure is a four-layer structure without the Si layer as the first reflection layer. A protective layer 12 made of a (ZnS) 80 (SiO2) 20 film is formed on a polycarbonate substrate 11 to a thickness of about 110 nm by using Ag2Ge20Sb22.
The Te56 recording film 14 has a thickness of about 20 nm and (ZnS) 80
An intermediate layer 15 composed of a (SiO2) 20 film has a thickness of about 20 nm.
The reflection layer 20 made of an Al97Ti3 film is
nm, and two disk members similarly prepared were adhered to obtain a disk-shaped information recording medium shown in FIG.

(Initial Crystallization) Initial crystallization was performed on the recording films 14 and 14 'of the medium manufactured as described above as follows. Note that the recording film 14 'is completely the same, so that only the recording film 14 will be described below.

When the linear velocity at a point on the recording track is 8 m /
The recording film 14 was irradiated through the substrate 11 with the laser light power of an oblong semiconductor laser (wavelength: about 810 nm) having a spot shape elongated in the radial direction of the medium at 800 mW. The recording head was driven while performing automatic focusing so that the laser beam was focused on the recording film 14. The movement of the spot was shifted by 1/16 of the spot length in the radial direction of the medium. Thus, initial crystallization was performed. This initialization may be performed once, but when it is repeated three times, the rise in noise due to the initial crystallization can be reduced slightly. This initial crystallization has the advantage that it can be performed at high speed. Further, it is preferable that the initial crystallization be performed at a laser wavelength at which recording / reproducing is performed or at a wavelength close thereto (670 nm to 700 nm), since the laser power can be reduced.

The initial crystallization may be performed in a drive having a semiconductor laser (having a wavelength of 680 nm).
In this case, the medium is rotated at a linear velocity of 6 m / s, and the laser beam power is set to a level at which recording or erasing is not performed (about 1 mW).
) And the laser light is applied to the numerical aperture (N
A) was condensed by a 0.6 lens, and the recording film 14 was irradiated through the substrate 11. The reflected light from the recording film 14 was detected, tracking was performed, and the recording head was driven while performing automatic focusing so that the laser light was focused on the recording film 14. The laser beam irradiation is a continuous (DC) laser beam on the same recording track, and is crystallized twice (4 mW) at the level of amorphization (10 mW).
Was performed twice. Each irradiation time (light spot transit time)
Is about 0.18 μsec. When the laser beams having different powers are irradiated as described above, the initial crystallization can be sufficiently performed.

In the initialization, light from a xenon lamp close to a point light source is condensed on a mask having slits radially opened in the radial direction of the disk in the vicinity of a disk rotated by an ellipsoidal mirror. It may be performed by passing light. A slit having a width of 0.5 mm or more is preferable because initialization can be performed in a short time, and a slit of 3 mm or less is preferable because initialization power can be reduced. When the length of the slit is 5 mm or more, the initialization time can be reduced, and when it is 30 mm or less, the initialization power can be reduced, which is preferable. The distance between the disk and the slit is preferably 1 mm or less because the power can be reduced. This initialization is preferable because the initial crystallization can be completed only by rotating the medium a few times.

(Recording and erasing) Next, while performing tracking and automatic focusing on the recording area of the recording film 14 on which the initial crystallization has been completed as described above, the power of the recording laser beam is changed to the intermediate power level Pm ( 5mW) and the high power level Ph (10mW) to record information. The linear velocity of the recording track is 6 m / s, the wavelength of the semiconductor laser is 680 nm, and the numerical aperture (NA) of the lens is 0.6.
An amorphous portion or a portion close to the amorphous portion formed in the recording area by the recording laser beam is a recording point.

The power ratio between the high level and the intermediate level of the recording laser beam is particularly preferably in the range of 1: 0.3 to 1: 0.6. In addition, other power levels may be set for each short time. As shown in FIG. 7, during the formation of one recording mark, the power is repeatedly reduced to a level lower than the intermediate power level by a half (Tw / 2) of the window width, and
1 time to keep high power level at the beginning of recording mark formation
When recording / reproducing was performed using a device having a means for generating a recording waveform in which the time width Tc of the cooling pulse for lowering the power Tw was finally set to 1 Tw, a particularly low jitter value and error rate of the reproduced signal waveform were obtained. . In this figure, 4T
Although only the recording waveforms of w and 11 Tw are shown,
In the case of 10 Tw, before the Tc of the 4 Tw waveform, one set of waveforms each maintaining Tw / 2 at the high power level and the low power level is added. 11 Tw is obtained by adding 7 sets to 4 Tw. For 3Tw, the time to maintain the high power level at the beginning of recording mark formation is 1.
The recording waveform becomes 5 Tw. The shortest recording mark length corresponding to 3 Tw was 0.62 μm. After passing through the portion to be recorded, the laser light power is reduced to the low power level Pr (1 mW) of the reproducing (reading) laser light.

In such a recording method, if new information is recorded by overwriting without erasing a portion in which information has already been recorded, the information is rewritten with new information. That is, overwriting with a single substantially circular light spot is possible.

However, during the first rotation or multiple rotations of the disk at the time of rewriting, continuous light having the intermediate power level (5 mW) of the power-modulated recording laser light or a power (6 mW) close to the intermediate power level is irradiated. Information is erased once, and then between the low power level (1 mW) and the high power level (10 mW) or the intermediate power level (5 mW) and the high power level (10 mW) in the next rotation. In the meantime, recording may be performed by irradiating a laser beam whose power is modulated according to the information signal. As described above, if the information is erased before recording, the previously written information is less likely to be erased, and a particularly low jitter value can be obtained. Therefore, recording with the shortest recording mark length shorter than 0.62 μm is also facilitated.

These methods are effective not only for the recording film used for the medium of the present invention but also for the recording film of another medium.

In the information recording medium of this embodiment, when recording and erasing are repeated under severe conditions in which the power of the laser beam is 15% higher than the optimum value, as shown in FIG. The jitter of the trailing edge (σ / Tw) and the jitter of the leading edge can be reduced by about 5% and about 3%, respectively, as compared with the information recording medium No. Further, it was possible to reduce the jitter of the leading edge even when the rewriting was performed 105 times or more. The window width (Tw) in jitter measurement is 34 ns, the shortest recording signal is 3 Tw, and the longest recording signal is 11 Tw, and these are recorded at random. No regenerative equalization circuit was used for these measurements. When a reproduction equalizer circuit was used, an effect of reducing jitter by 1 to 3% was further observed. In addition, the width of the region where the recording film flows and the recording material runs short at the recording start end and a large distortion of the reproduced signal waveform due to accumulation at the end end, is set to 15 at the start end.
It could be reduced to less than Byte equivalent or less than 5 Byte equivalent at the end. In the case of a conventional structure disk, the size is 20 bytes and 30 bytes, respectively.

In the case where the intermediate layer 15 was omitted from this disk, the jitter was increased by one digit less rewriting than the above. However, the increase in jitter was smaller than in the case where the intermediate layer 15 was omitted in the conventional structure disk. Also, the recording power Ph is 1 m, compared to the case where a part of the intermediate layer 15 on the recording film side is changed to Al2O3.
W lowered.

(Spectral Characteristics of Information Recording Medium) Two similar test pieces were produced with the same structure as the above disk member except that the substrate was changed to glass, and the wavelength was 400 to 1000 nm.
The spectral characteristics were examined. FIG. 9 shows the reflectance in the wavelength range of 500 to 850 nm. That is, a glass face plate having a thickness of about 1 mm that has been optically polished is used as a substrate, and a first protective layer 12 made of a (ZnS) 80 (SiO2) 20 film is formed on the substrate.
Was formed to a thickness of about 90 nm. Next, a second protective layer 13 made of an Al2 O3 film is formed to a thickness of about 5 nm with a thickness of Ag2 Ge20 Sb22 Te5.
6 The recording film 14 is made of (ZnS) 80 (SiO
2) The intermediate layer 15 made of 20 films is about 20 nm thick, the first reflective layer 16 made of Si is about 90 nm thick, and Al97Ti
A second reflective layer 17 composed of three films was formed in a thickness of about 200 nm sequentially in the same manner as in the disk member. One of the test pieces obtained in this way is intact and the other is 30
Heat treatment was performed at 0 ° C. for 5 minutes. Each test piece was irradiated with light from the substrate side, and the wavelength dependence of the reflectance was measured. The reflectance in the case where the heat treatment was performed is shown by Rc in the figure, and the reflectance in the state as it is is shown by Ra in the figure. When the heat treatment is performed, the same optical characteristics as those in the state where the initial crystallization is performed using the elliptical semiconductor laser beam are obtained.

From this, it was found that in the disk having good rewritability described in this example, the reflectance had a minimum value in the wavelength range of 400 nm to 800 nm. In addition, the recording / reproducing wavelength remains unchanged (Ra)
At a reflectance of 10% or less, and 15 after heating (Rc).
% Or more.

With respect to the disc having the conventional structure, a test piece having the same structure as that of the disc except for the substrate was prepared, and the same measurement was carried out.
In the range of 0 nm to 850 nm, it was found that there was no minimum value.

When these spectral characteristics are measured with a disk, the wavelength dependence of the light absorption of the substrate is observed, so that it may be difficult to determine the positions of the minimum value and the maximum value. In particular, when the wavelength is 650 nm or less, the reflectance tends to be considerably lower than the actual value.

In the disk having good rewriting characteristics described in this example, the disk member was peeled off between the recording film and the intermediate layer, and the reflectance was measured from the intermediate layer side to the reflective layer (Rupl). The measurement was also performed when the disk member was peeled off between the intermediate layer and the reflective layer (Rref). As partially shown in FIG. 10, it was found that the wavelength dependence of the reflectance was large, and the difference between the maximum value and the minimum value was 20% or more in the wavelength range of 400 nm to 850 nm. It was found that the difference was greater than 40% for the larger disks.

When the same measurement is performed on the conventional structure disk, the difference between the maximum value and the minimum value is 5% or less when the recording film is peeled off from the intermediate layer, and when the recording film is peeled off between the intermediate layer and the reflection layer. Was found to have a difference of 10% or less.

As described above, it was found that the spectral characteristics of the disk having good rewritability described in the present embodiment were different from the spectral characteristics of the conventional structure disk.

(Material for Recording Film) In this embodiment, the recording films 14, 1
As a material of the recording film instead of Ag2Ge20Sb22Te56 used for 4 ', Ag5Ge20Sb20Te55, Ag1
In the case of materials such as Ge21Sb23Te55 and Ag-Ge-Sb-Te having different composition ratios, the number of rewritable times hardly decreases. As the amount of Ag increases, the recording sensitivity improves, but the disappearance increases. Further, when the Ag amount is reduced, the erasing characteristics are improved, but the recording sensitivity is reduced. Ag-Ge-Sb-T
In the e system, Ag is 1 to 5 atomic%, Ge is 17 to 23 atomic%, Sb is 19 to 25 atomic%, and Te is 53 to 59 atomic%.
It has been found that a composition in the range of (1) does not particularly cause a decrease in the number of rewritable times. It is also found that a composition in which AgSbTe2 or a material close thereto is 2 to 20% and Ge2Sb2Te5 or a material close thereto occupies the remainder has a large reflectance difference between a crystalline state and an amorphous state, and is preferable because a reproduced signal becomes large. Was.

Next, ((Cr4Te5) 10 (Ge2Sb)
Even with a Cr-Ge-Sb-Te-based recording film such as 2Te5) 90), the jitter of 30,000 times or more of rewriting increases, but similar good results were obtained in many other characteristics. W-Ge-
In the Sb-Te system, W is 1 to 5 atomic% and Ge is 17 to 2%.
3 atomic%, Sb is 19-25 atomic%, Te is 53-59
It has been found that the composition in the range of atomic% reduces the unerased residue particularly during rewriting.

In general, such a recording film is made of Ge—Sb—
This is a recording film to which a phase change component containing Te as a main component and a high melting point component having a higher melting point are added. 95% or more of the total number of atoms of the phase change component is composed of a combination of GeTe and Sb2Te3, and 95% or more of the total number of atoms of the high melting point component is Cr-T.
e, Cr-Sb, Cr-Ge, Cr-Sb-Te, Cr
-Sb-Ge, Cr-Ge-Te, Co-Te, Co
-Sb, Co-Ge, Co-Sb-Te, Co-Sb-
Ge, Co-Ge-Te, Cu-Te, Cu-Sb,
Cu-Ge, Cu-Sb-Te, Cu-Sb-Ge, C
u-Ge-Te, Mn-Te, Mn-Sb, Mn-G
e, Mn-Sb-Te, Mn-Sb-Ge, Mn-Ge
-Te, V-Te, V-Sb, V-Ge, V-Sb-
Te, V-Sb-Ge, V-Ge-Te, Ni-Te,
Ni-Sb, Ni-Ge, Ni-Sb-Te, Ni-S
b-Ge, Ni-Ge-Te, Mo-Te, Mo-S
b, Mo-Ge, Mo-Sb-Te, Mo-Sb-G
e, Mo-Ge-Te, W-Te, W-Sb, WG
e, W-Sb-Te, W-Sb-Ge, W-Ge-T
e, Ag-Te, Ag-Sb, Ag-Ge, Ag-Sb
When the composition is at least one of -Te, Ag-Sb-Ge, and Ag-Ge-Te, or a composition close to this, the number of rewritable times is less likely to decrease. Cr4Te5, Cr
2Te3, Cr5Te8, Cr-Te, etc.
It was found that the jitter of 0 to 10,000 times was particularly low. W
-Te, W-Sb, W-Ge, W-Sb-Te, WS
It has been found that b-Ge and W-Ge-Te have a particularly small number of unerased portions during rewriting. Ag2Te, A
gSbTe2 and the like have a large signal intensity even when the light source wavelength is short, and it has been found that Ag-Te and Ag-Sb-Te are particularly good.

If the composition of 95% or more of the total number of atoms of the phase change component is Ge2Sb2Te5, the proportion of the high melting point component atoms in the total number of atoms of the recording film is 5 atomic% or more and 20 atomic% or less. Good characteristics. If the content is 5 at% or more and 15 at% or less, the erasing characteristics are good, so the rewriting characteristics are better.

Further, Ge2Sb2Te5, G
eSb2Te4, GeSb4Te7, In3SbTe2, In
35Sb32Te33, In31Sb26Te43, GeTe, Ag
-In-Sb-Te, Co-Ge-Sb-Te, V-Ge-S
b-Te, Ni-Ge-Sb-Te, Pt-Ge-Sb-T
e, Si-Ge-Sb-Te, Au-Ge-Sb-Te, Cu
-Ge-Sb-Te, Mo-Ge-Sb-Te, Mn-Ge-S
b-Te, Fe-Ge-Sb-Te, Ti-Ge-Sb-T
e, Bi-Ge-Sb-Te, W-Ge-Sb-Te, and at least one of the compositions close to these, or even if a part of Ge is replaced with In, a characteristic close to this is obtained. Can be

When the composition of each recording film contains 15 atomic% or less of nitrogen, the reproduction signal output is slightly reduced, but has the advantage that the recording film flow at the time of rewriting many times is suppressed.

The impurity element in the recording film, that is, an element not described above, is preferably 10 atomic% or less of the recording film component because the deterioration of the rewriting characteristics can be reduced. More preferably, the content is 5 atomic% or less.

The thickness of the recording film is preferably 10 nm or more and 30 nm or less, since the degree of modulation is large and flow is unlikely to occur. 26
nm or less is more preferable.

In the recording film of the present invention, recording is performed by a change in the atomic arrangement. The change in the atomic arrangement refers to a change in the atomic arrangement that hardly involves a change in the outer shape of the film such as a phase change.

(Protective Layer, Intermediate Layer, Substrate Material, etc.) In this embodiment, the first protective layer 12 is made of (ZnS) 80 (SiO2) 20.
(Molar ratio), but instead of this, the recording sensitivity and jitter slightly deteriorate, but ZnS and SiO2
(SiO 2 is 15 to 20 mol%), and a material having a composition close to the mixed composition of ZnS and the following oxide 10 to 40 mol% is preferable. The mixed oxide is SiO
2, SiO, TiO2, Al2O3, Y2O3, CeO, La
2O3, In2O3, GeO, GeO2, PbO, SnO,
SnO2, Bi2O3, TeO2, WO2, WO3, Sc2O
3, Ta2O5 and ZrO2 are preferred. In addition, oxides such as Si-N-based materials, Si-ON-based materials, Si-Al-ON-based materials, TaN, AlN, Si3N4, Al-Si
-Nitrides such as N-based materials 2), ZnS, Sb2S3, Cd
S, In2S3, Ga2S3, GeS, SnS2, PbS,
Sulfides such as Bi2S3, SnSe2, Sb2Se3, Cd
Se, ZnSe, In2Se3, Ga2Se3, GeSe,
Selenides such as GeSe2, SnSe, PbSe, Bi2Se3, fluorides such as CeF3, MgF2, CaF2,
Alternatively, Si, Ge, or a material having a composition close to the above materials may be used. Further, a layer of these mixed materials may be used. Further, a multi-layer protective layer in which protective layers having different components are stacked as in this embodiment may be used.

As a material instead of the second protective layer Al2O3, a material mainly composed of Al2O3, SiO2, SiO2
Is more preferable because it has a high thermal conductivity and can reduce an increase in jitter which is observed in the vicinity of the rewriting of the rear edge 10 to 100 times.

When forming the first protective layer or the second protective layer,
After forming the protective layer material with a thickness of 1 nm or more, sputtering may be performed in the opposite direction, that is, the direction in which the substrate material side is etched, and the thicker protective layer material may be etched to have an appropriate thickness. Although this method requires an extra time for the production, the surface of the protective layer can be made flatter and the disk noise can be reduced. This method is more effective when forming a layer in contact with the recording film.

The total thickness of the protective layer is 60 nm or more and 11
A value of 0 nm or less is preferable because the modulation degree can be increased and a rise in jitter upon rewriting many times is small. When the protective layer is composed of only the first protective layer, the total thickness is the thickness of the protective layer,
When it comprises the first protective layer and the second protective layer, it refers to the sum of the thicknesses of both. Further, in this embodiment, the protective layer is formed of the first protective layer and the second protective layer. However, although the formation of a plurality of layers complicates the manufacturing process, the rewriting characteristics can be improved. There is an advantage that the recording sensitivity can be improved. When the protective layer is composed of a single first protective layer, there is a disadvantage that any one of the recording sensitivity and the rewriting characteristic is slightly lowered, but there is an advantage that the manufacturing process is simplified.

In this embodiment, the intermediate layer 15 is made of (ZnS) 80
(SiO 2) 20 (molar ratio), but instead of this, the recording sensitivity and jitter are slightly deteriorated.
In which the mixing ratio of nS and SiO2 is changed (SiO2 is 15 ~
20 mol%), and a material having a composition close to the mixed composition of ZnS and the following oxide 10 to 40 mol% is preferable. Oxides to be mixed are SiO2, SiO, TiO2, Al2 O3, Y2 O3, Ce.
O, La2O3, In2O3, GeO, GeO2, PbO,
SnO, SnO2, Bi2O3, TeO2, WO2, WO3,
Sc2O3, Ta2O5 and ZrO2 are preferred. S
i-N-based material, Si-ON-based material, Si-Al-O-
Oxides such as N-based materials, TaN, AlN, Si3N4, A
nitrides such as l-Si-N-based materials (for example, AlSiN2), ZnS, Sb2S3, CdS, In2S3, Ga2S3,
Sulfides such as GeS, SnS2, PbS, Bi2S3, S
nSe2, Sb2Se3, CdSe, ZnSe, In2Se
3, Ga2Se3, GeSe, GeSe2, SnSe, Pb
Se, selenide such as Bi2 Se3, CeF3, MgF
2. A fluoride such as CaF2, or Si, Ge, or a material having a composition close to the above materials may be used. Further, a layer of these mixed materials or a multilayer thereof may be used.

The ratio of elements in these compounds is, for example, the ratio of metal element to oxygen or the ratio of metal element to sulfur in oxides and sulfides, for Al 2 O 3, Y 2 O 3, La 2
O3 is 2: 3, SiO2, ZrO2, GeO2 is 1: 2,
It is preferable that the ratio of Ta2O5 is 2: 5 and the ratio of ZnS is 1: 1 or close to the ratio, but the same effect can be obtained even if the ratio is out of the ratio.

The thickness of the intermediate layer is preferably 40 nm or less.
In the case of 0 nm, that is, the intermediate layer can be omitted,
In this case, since the number of layers is reduced by one, the production of the information recording medium becomes easy. In order to suppress the flow of the recording film, 40 nm
It is preferable to set the following. In particular, in the structures of Examples 1 to 5, when the thickness of the intermediate layer is 15 to 30 nm, the recording / reproducing characteristics are further improved, which is preferable. These film thicknesses refer to the thickness of the intermediate layer when it is composed of only one layer, and the sum of the film thicknesses of all the layers when the intermediate layer is composed of multiple layers.

In this embodiment, the polycarbonate substrate 11 having pits indicating addresses and the like and tracking grooves directly on the surface is used. Instead, a polyolefin, epoxy, acrylic resin, ultraviolet curable resin is used. Chemically strengthened glass having a resin layer formed on the surface may be used.
Further, not only a substrate of a continuous (continuous) servo format, but also a substrate of a sample servo format or a substrate of another format may be used. A substrate having a land / groove format in which recording and reproduction can be performed on both the groove and the land may be used. 1 disk size
The size is not limited to 2 cm, but may be 13 cm, 3.5 inches, 2.5 inches, or other sizes. 0.6mm disc thickness
However, although it is desirable in that a stop lens having a large NA can be used, other thicknesses such as 1.2 mm and 0.8 mm may be used.

In this embodiment, the intermediate layers 15, 15 'are omitted, and the first reflection layers 16, 16' are formed on the recording films 14, 14 '.
The same characteristics can be obtained by directly forming in this case,
Since the number of layers is reduced by one, the disk can be easily manufactured and the manufacturing time can be shortened.

In this example, two disk members were produced in exactly the same manner, and
A second reflection layer 17 of the first and second disk members,
Although the 17's are bonded together, a disk member of another configuration or a protection substrate may be used instead of the second disk member. When the transmittance in the ultraviolet wavelength region of the disk member or the protective substrate used for bonding is large, the bonding can be performed using an ultraviolet curable resin. The bonding may be performed by another method.

In this embodiment, two disk members are manufactured, and the protective coating layers 18 and 18 'of the first and second disk members are bonded to each other via an adhesive layer. The error rate can be lower than in the case where the two reflection layers 17 and 17 'are bonded together. Further, the second reflection layer 1 of the first and second disk members
When the layers 7 and 17 'are directly bonded to each other, the error rate slightly increases, but the manufacturing time can be reduced.

(First Reflective Layer) In this embodiment, the first reflective layer 1
S as a material for the first reflective layer instead of Si used in No. 6
Ge, Au, Ag, Cu, Al, Ni, Fe, C
o, Cr, Ti, Pd, Pt, W, Ta, Mo, Sb,
Bi, Dy, Cd, Mn, Mg, V, Sn, Zn, I
When n, Ga, Tl, Pb, N, C, B, and S are added,
Since the transmittance of the reflective layer decreases and the absorptance increases, a decrease in sensitivity can be prevented. When the content of the additional element other than Ge, Sn, In, and N is 1 atomic% or more and 25 atomic% or less, a change in the reflectivity level at the time of rewriting many times hardly occurs.

Among the above, the Si-Ge mixed material for both Si can make the light absorption of the recording mark portion smaller than that of the portion other than the recording mark, so that the disappearance due to the difference in the light absorption can be prevented. The number of rewritable times does not decrease. When the content of Ge is 10 atomic% or more and 80 atomic% or less, the number of rewritable times hardly decreases.

Next, Si—N, Si—Sn or Si
Similar results were obtained with the -In mixed material or a mixed material of two or more of these mixed materials. Even if these reflective layer materials are used not only for the phase change film of the present invention but also for the case where another phase change film is used, the number of rewritable times does not decrease as compared with the conventional reflective layer material. When the content of the element added to Si is 3 atomic% or more and 50 atomic% or less, the number of rewritable times hardly decreases. Further, a layer made of a mixed material containing Si and Ge other than those described above, a material having a large refractive index and a small extinction coefficient may be used, or a multi-layer made of those phases may be used. It has been found that the use of a composite layer with another substance such as a substance does not cause a decrease in the number of times of rewriting, which is preferable. Ge can also be used. In addition, various nitrides, sulfides, selenides, and alloy materials having optical constants different from those of the second reflective layer can be used.

In addition, materials other than those described above having a refractive index of 3 or more and an extinction coefficient of 2 or less at a recording wavelength or a reproduction wavelength can be used. For example, an Al alloy or stainless steel in which the amount of an additive to Al is 5 atomic% or more,
Low thermal conductivity metals such as nichrome and Sb-Bi may be used.

It is preferable that the above-mentioned Si and the material of the first reflection layer instead of Si be 90% or more of the total number of atoms of the first reflection layer. When the amount of impurities other than the above-mentioned materials became 10 atomic% or more, deterioration of the rewriting characteristics was observed.

The thickness of the first reflection layer is 50 nm to 100 nm.
It is preferable because recording and reproduction characteristics can be improved.

(Second Reflective Layer) In this embodiment, the second reflective layer 17 is used.
Al-Ti, Al-Ag, Al-Cu, Al-Cr,
A material mainly composed of an Al alloy such as Al-Co is preferable.
Al can also be used. Since the Al alloy is soft, there is an advantage that interfacial peeling or the like due to internal stress does not easily occur.

In the case of an Al alloy, when the content of Al is 50 atomic% or more and 99.9 atomic% or less, the thermal conductivity can be increased, and the number of rewritable times hardly decreases.

In addition, other Al alloys, Au, Ag,
Cu, Al, Ni, Fe, Co, Cr, Ti, Pd, P
t, W, Ta, Mo, Sb, Bi, Dy, Cd, Mn,
Mg, V element simple substance, Au alloy, Ag alloy, Cu
Alloy, Pd alloy, Pt alloy, Sb-Bi, SUS, Ni
-Cr, an alloy containing these as a main component, or a layer made of an alloy of these may be used, a multi-layer made of these layers may be used, or these and other substances such as oxides may be used. Or a composite layer of these with another substance such as another metal. This has a similar effect.

Among them, Cu, Al, Au, Cu alloy,
A disk having a large thermal conductivity, such as an Al alloy or an Au alloy, has a quenched disk structure, and is unlikely to have a change in reflectance due to rewriting many times. Ag, Ag alloy, and the like have similar characteristics. Also, Sb-Bi, Dy, SU
Those having a small thermal conductivity, such as S and Ni-Cr, have an advantage that the recording sensitivity is improved because the temperature is easily maintained.

In the case of using Mo or a Mo compound, the reactivity is low, there is no possibility that the characteristics will be degraded by reacting with the first reflection layer by a large number of laser irradiations, and a hard film having a large Young's modulus is used. Therefore, there is an effect that the flow of the recording film due to thermal deformation is suppressed, and there is an advantage that the rewriting characteristics do not deteriorate. Next, similar results were obtained for W and W compounds. However, for these materials, especially W, it is necessary to select film forming conditions that reduce the internal stress.

Further, compared to Au alone, Au-Ag,
Au alloys such as Au-Co and Au-Al are preferred because they have the advantage of increasing the adhesive strength.

As long as the first reflective layer has a different refractive index and extinction coefficient from the first reflective layer, an alloy containing Si, Ge, Sn, or In as a main component, or a layer made of an alloy of these elements and the above elements may be used. Or a multi-layer of these layers, a composite layer of these with another substance such as an oxide, a composite layer of these with another substance such as another metal, or the like. Good. Further, the extinction coefficient k of the material is preferably 3 or more.

It is preferable that the material of the second reflective layer instead of Al—Ti and Al—Ti is 80% or more of the total number of atoms of the second reflective layer. When the amount of impurities other than the above-mentioned materials became 20 atomic% or more, deterioration of the rewriting characteristics was observed.

As the material of the third reflective layer formed between the first reflective layer and the intermediate layer, any of the above-mentioned materials which can be used for the second reflective layer can be used.

The thickness of the second reflective layer is more preferably at least 50 nm from the viewpoint of increasing the strength and the thermal diffusion, and is preferably at most 350 nm from the viewpoint of reducing the production time. 50 nm to 250 nm
Is more preferable.

(Thickness and Material of Each Layer) The recording and reproducing characteristics and the like can be improved by simply setting the thickness and material of each layer independently. However, by combining the respective preferable ranges, further effects can be obtained. Go up.

(Combination of First Reflective Layer Material and Second Reflective Layer Material) For the first reflective layer material,
As the material for the reflective layer, the materials described in Example 1 and this example can be used, but it was found that the rewriting characteristics were improved by selecting a combination of these materials. A preferred combination is that the first reflective layer is made of Si, Si-Ti, Si-
At least one of Mo, Si-Al, Si-Ge, Ge
Or a composition close thereto, wherein the second reflective layer is made of Al,
Al alloy, Au, Au alloy, Ag, Ag alloy, Cu, C
u alloy, Pt, Pt alloy, Mo, Mo compound, Sb-B
i At least one of the solid solutions or a composition close thereto.

An Al—Cr alloy, a second reflective layer
It is preferable to use an Al-Ti alloy in combination with the reflective layer because the recording sensitivity is increased and the number of rewritable times is increased.

In a preferred combination, 90% or more of the total number of atoms in the first reflective layer is made of Si, and 90% or more of the total number of atoms in the second reflective layer is Al-T.
i, one of Al-Ag, Al-Cu, Al-Cr, and Al-Co. Further, a component that is 90% or more of the total number of atoms of the first reflective layer is Si, Si-T.
i, Si-Mo, Si-Al, Si-Ge, Ge, and at least 90% of the total number of atoms of the second reflective layer are at least one of Mo and Mo compounds. Or the first reflective layer is made of Si, Si-Ti, Si-Mo, Si-Al, S
at least one of i-Ge and Ge, or a composition close thereto, wherein the second reflective layer is made of Al, Al alloy, Au, A
u alloy, Ag, Ag alloy, Cu, Cu alloy, Pt, Pt
In the case of at least one of an alloy, Mo, a Mo compound, and an Sb-Bi solid solution, or a composition close to this, components of 90% or more of the total number of atoms of the first reflective layer are Si-Ti, Si-M
o, at least one of Si-Al, and 90% or more of the total number of atoms of the second reflective layer is Al-T.
i, Al-Ag, Al-Cu, Al-Cr, and Al-Co.

The difference between the refractive index and the extinction coefficient of the first reflective layer and the second reflective layer is 0.5 or more, and at least one of the refractive index and the extinction coefficient of the first reflective layer and the second reflective layer. When the difference is 2 or less, jitter during rewriting can be reduced, which is preferable. The refractive index of the first reflective layer is 5 or less, the refractive index of the second reflective layer is 2 or less, and the extinction coefficient of the first reflective layer is 5 or less, or the extinction coefficient of the second reflective layer is 5 or less. Even with the above, similar characteristics can be obtained. In this case, the first
When the refractive index of the reflective layer is 3 or less, the degree of modulation is further increased, which is preferable. In addition, when a third reflective layer is provided on the other layer side of both the first reflective layer and the second reflective layer, the film forming process becomes complicated, but the unerased portion during rewriting is reduced. have. It is preferable that the thickness of the third reflective layer is smaller than the thickness of any of the first reflective layer and the second reflective layer because the film formation time can be reduced.

Embodiment 11 (Structure and manufacturing method) Intermediate layer 14 (ZnS) 80 of Embodiment 10
The following information recording medium was prepared in the same manner as in Example 10 except that (SiO2) 20 was changed to Al2O3. That is, the information recording medium in Example 11 has a diameter of 12 cm.
Polycarbonate substrate 1 having a thickness of 0.6 mm and pits representing addresses and the like on its surface and tracking grooves
1, a (ZnS) 80 (SiO2) 2 film having a thickness of about 95 nm
A first protective layer 12 made of a 0 film, a second protective layer 13 made of an Al2O3 film having a thickness of about 5 nm, and Ag2Ge20Sb2 having a thickness of about 20 nm.
Recording film 14 of 2Te56 film, Al2O with a thickness of about 25 nm
Intermediate layer 15 made of three films, first reflective layer 16 made of Si
A second reflective layer 17 made of an Al97Ti3 film having a thickness of about 80 nm and a thickness of about 200 nm was laminated. The first disk member and the second disk member thus obtained in exactly the same manner.
The protective coating layers 18 and 18 'of the disk member were bonded together to obtain a disk-shaped information recording medium.

(Recording / Reproducing Characteristics) The recording / reproducing characteristics were examined in the same manner as in Example 10. It was found that in the disk of the present embodiment, the change in reflectivity that occurs after 105 rewritings can be reduced by 5% as compared with a disk whose protective layer material is made of (ZnS) 80 (SiO2) 20. However, the recording sensitivity was reduced by about 5%.

(Protective Layer Material, etc.) In this embodiment, the protective layer is formed by the first protective layer (ZnS) 80 (SiO 2) 20 and the second protective layer Al 2 O 3. Alternatively, it is preferable to use a mixed material of Al2O3 and SiO2 or a mixed material of Al2O3 and ZnS.
Next, Ta2O5 and (ZrO2) 97 (Y2O3) 3 are preferred. Also, La2O3 and GeO2 may be used. The element ratio in these compounds is, for example, the ratio of the metal element to the oxygen element in oxides and sulfides, or the ratio of the metal element to the sulfide element in Al2O3, Y2O3, and La2O3 is 2:
3: SiO2, ZrO2, GeO2 1: 2, Ta2O5
Preferably has a ratio of 2: 5 and ZnS has a ratio of 1: 1 or is close to the ratio, but the same effect can be obtained even if the ratio is out of the ratio.

In the case of such a protective layer, Al 2 O 3
The thickness of the film or an alternative film is preferably 2 to 50 nm because the recording power can be set to an appropriate value. 3 nm or more 2
More preferably, it is 0 nm or less. The thickness of the entire protective layer is preferably from 80 to 110 nm because the degree of modulation during recording can be increased.

The material of the protective layer of the present embodiment is such that the intermediate layer of the recording medium of the tenth embodiment is made of a material other than the Al2O3 film, for example, (ZnS)
The same effects as described above can be obtained by using a material mainly composed of ZnS such as 80 (SiO2) 20 or a material mainly composed of SiO2.

[0276] However, the effect of the Al2O3 film as the intermediate layer, which is an effect of suppressing the increase in jitter at the time of rewriting 100,000 times, is small.

In addition to the disc having the structure shown in the present invention, a disc having a conventional structure and a phase-change disc having a protective layer also include a part of the material of Al 2
Providing the O3 film has the effect of reducing the change in reflectance that occurs during multiple rewriting. However, the effect of suppressing the increase in jitter at the time of rewriting 100,000 times is small.

Even if the protective layer of the present embodiment is used when there is no second reflective layer, the thickness of the first reflective layer must of course be changed so that the reproduction signal modulation degree is large. Has the effect.

Items not described in this embodiment are described in Embodiment 1.
Same as 0.

Embodiment 12 (Structure and manufacturing method)
The following information recording medium was produced in the same manner as in Example 10 except that ZnS was used for a part of the opposite side of the 2O3 recording film. In other words, the information recording medium in Example 12 is (ZnS) 80 having a thickness of about 95 nm in order on a polycarbonate substrate 11 having a diameter of 12 cm, a thickness of 0.6 mm, and pits indicating addresses and the like on its surface and tracking grooves. (S
a first protective layer 12 composed of an (iO2) 20 film, a second protective layer 13 composed of an (Al2O3) 80 film having a thickness of about 5 nm, and a thickness of about 20;
a recording film 14 composed of an Ag2Ge20Sb22Te56 film having a thickness of nm.
An Al2O3 film having a thickness of about 10 nm and (Zn) having a thickness of about 20 nm
S) The intermediate layer 15 made of a 80 (SiO2) 20 film and the first reflective layer 16 made of Si are formed to a thickness of about 80 nm and a thickness of about 200 n.
A second reflective layer 17 made of an Al97Ti3 film was formed. Thus, the protective coating layers 18, 18 'of the first disk member and the second disk member obtained by exactly the same method were adhered to each other to obtain a disk-shaped information recording medium.

(Recording / Reproducing Characteristics) The recording / reproducing characteristics were examined in the same manner as in Example 10. It has been found that the recording power of the disk of this embodiment can be reduced by 5% as compared with a disk in which the intermediate layer is made of Al2O3.

When the disk having the protective layer shown in Embodiment 11 and the intermediate layer of this embodiment are combined, both effects can be obtained. When the protective layer shown in Example 11 and the intermediate layer of this example are combined, a total effect can be obtained. In addition to the disc having the structure shown in the present invention, a disc having a conventional structure and a phase-change disc having an intermediate layer also include Al2O3 and (ZnS) 80 (SiO2) 2
By using the film formed with 0, the effect of reducing the recording power can be obtained.

(Protective Layer Material, etc.) In this embodiment, the intermediate layer 1
5 is made of (ZnS) 80 (SiO2) 20 and Al2 O3, but a material that can replace Al2 O3 is Si.
O2 or a mixed material of Al2 O3 and SiO2 is preferably used. Then, Ta2O5, (ZrO2) 97 (Y2O3) 3,
Is preferred. Also, La2O3 and GeO2 may be used.

In the case of such an intermediate layer, Al2O
It is preferable that the thickness of the three films or the alternative film be 2 to 15 nm because the recording power can be set to an appropriate value.

In particular, in the conventional disk shown in FIG. 6, the intermediate layer 15 is made of (ZnS) 80 (SiO2) 20 and A
In the case of using l2O3, the recording / reproducing characteristics were improved when the total thickness of the intermediate layer was 160 to 210 nm.

When the disk having the protective layer shown in Embodiment 11 and the intermediate layer of this embodiment are combined, both effects can be obtained. When the protective layer shown in Example 11 and the intermediate layer of this example are combined, a total effect can be obtained.

In addition to the disc having the structure shown in the present invention, not only the disc having the conventional structure, but also the phase change disc having the intermediate layer, the recording sensitivity of the recording medium can be reduced by using the intermediate layer as in this embodiment. The decrease is smaller than that in the case of the Al2O3 intermediate layer, and it is possible to reduce the change in the reflectance at the time of rewriting 100,000 times, and it is possible to obtain an effect that the recording power margin is increased. However, the rise of the jitter is larger than that of the disk having the structure shown in the present invention.

Even if the intermediate layer of this embodiment is used without the second reflection layer, the thickness of the first reflection layer must be changed so that the modulation degree of the reproduction signal is large. Has the effect.

Items not described in this embodiment are described in Embodiment 1.
Same as 0.

Embodiment 12 (Structure and manufacturing method)
The following information recording medium was produced in the same manner as in Example 10 except that ZnS was used for a part of the opposite side of the 2O3 recording film. In other words, the information recording medium in Example 12 is (ZnS) 80 having a thickness of about 95 nm in order on a polycarbonate substrate 11 having a diameter of 12 cm, a thickness of 0.6 mm, and pits indicating addresses and the like on its surface and tracking grooves. (S
a first protective layer 12 composed of an (iO2) 20 film, a second protective layer 13 composed of an (Al2O3) 80 film having a thickness of about 5 nm, and a thickness of about 20;
a recording film 14 composed of an Ag2Ge20Sb22Te56 film having a thickness of nm.
An Al2O3 film having a thickness of about 10 nm and (Zn) having a thickness of about 20 nm
S) The intermediate layer 15 made of a 80 (SiO2) 20 film and the first reflective layer 16 made of Si are formed to a thickness of about 80 nm and a thickness of about 200 n.
A second reflective layer 17 made of an Al97Ti3 film was formed. Thus, the protective coating layers 18, 18 'of the first disk member and the second disk member obtained by exactly the same method were adhered to each other to obtain a disk-shaped information recording medium.

(Recording / Reproducing Characteristics) The recording / reproducing characteristics were examined in the same manner as in Example 10. It has been found that the recording power of the disk of this embodiment can be reduced by 5% as compared with a disk in which the intermediate layer is made of Al2O3.

When the disk having the protective layer shown in Embodiment 11 and the intermediate layer of this embodiment are combined, both effects can be obtained. When the first reflective layer, the protective layer shown in Example 11, and the intermediate layer of this example are combined, a total effect can be obtained. In addition, not only the disc of the structure shown in the present invention,
Even in a conventional structure disk and a phase change disk having an intermediate layer, the intermediate layer is made of Al2O3 and (ZnS).
By forming a film made of 80 (SiO2) 20,
There is an effect that the recording power can be reduced.

(Protective Layer Material, etc.) In this embodiment, the intermediate layer 1
5 is made of (ZnS) 80 (SiO2) 20 and Al2 O3, but a material that can replace Al2 O3 is Si.
O2 or a mixed material of Al2 O3 and SiO2 is preferably used. Then, Ta2O5, (ZrO2) 97 (Y2O3) 3,
Is preferred. Also, La2O3 and GeO2 may be used.

In the case of such an intermediate layer, Al 2 O
It is preferable that the thickness of the three films or the alternative film be 2 to 15 nm because the recording power can be set to an appropriate value.

Particularly, in the conventional disk shown in FIG. 6, the intermediate layer 15 is made of (ZnS) 80 (SiO2) 20 and A
In the case of using l2O3, the recording / reproducing characteristics were improved when the total thickness of the intermediate layer was 160 to 210 nm.

When the disk having the protective layer shown in Embodiment 11 is combined with the intermediate layer of this embodiment, both effects can be obtained. When the first reflective layer and the intermediate layer of this embodiment are combined, both effects can be seen. When the first reflective layer, the protective layer shown in Example 11, and the intermediate layer of this example are combined, a total effect can be obtained.

In addition to the disk having the structure shown in the present invention, not only the disk having the conventional structure but also the phase change disk having the intermediate layer, the recording sensitivity of the recording medium can be reduced by using the intermediate layer as in this embodiment. The decrease is smaller than that in the case of the Al2O3 intermediate layer, and it is possible to reduce the change in the reflectance at the time of rewriting 100,000 times, and it is possible to obtain an effect that the recording power margin is increased. However, the rise of the jitter is larger than that of the disk having the structure shown in the present invention.

Even if the intermediate layer of this embodiment is used when there is no second reflective layer, the thickness of the first reflective layer must be changed so that the modulation degree of the reproduction signal is large. Has the effect.

Items not described in this embodiment are described in Embodiment 1.
Same as 0 and 11.

Example 13 (Structure and manufacturing method) The substrate 11 and the first protective layer 12 of Example 10
The following information recording medium was produced in the same manner as in Example 10 except that the high-sensitivity super-resolution readout layer 26 was provided between the two.
(FIG. 11) That is, an example of the information recording medium in the twelfth embodiment has a film thickness of about 12 cm 2 and a thickness of 0.6 mm on a polycarbonate substrate 11 having pits representing addresses and the like and tracking grooves on the surface. 300 nm
[(SiO2) 71 (Na2O) 14 (CaO) 8 (Mg
O) 6 (Al 2 O 3) 1] 80 [(Co 3 O 4)] 20 high-sensitivity super-resolution readout layer 26 with a thickness of about 70 nm (ZnS)
First protective layer 12 of 80 (SiO2) 20 film, about 5 film thickness
second protective layer 13 of Al2O3 film having a thickness of about 20 nm and a thickness of about 20 nm.
Ag2Ge20Sb22Te56 nm recording film 14, thickness of about 2
An intermediate layer 15 of 0 nm (ZnS) 80 (SiO2) 20 film, a first reflective layer 1 of Si of about 80 nm thickness
6. A second reflective layer 17 made of an Al97Ti3 film having a thickness of about 200 nm, and a protective coating layer 18 of an ultraviolet curable resin was formed thereon in this order. Thus, a first disk member was obtained. Thus, the protective coating layers 18, 18 'of the first disk member and the second disk member obtained by exactly the same method were adhered to each other to obtain a disk-shaped information recording medium.

The same conventional disc-shaped information recording medium as that used in Example 10 was used for comparison. The information recording / reproducing method was the same as in Example 10.

(Initial Crystallization) Initial crystallization was performed on the recording films 14 and 14 'of the medium manufactured as described above as follows. Note that the recording film 14 'is completely the same, so that only the recording film 14 will be described below.

When the medium has a linear velocity of 8 m / point at a point on the recording track.
The recording film 14 was irradiated through the substrate 11 with the laser light power of an oblong semiconductor laser (wavelength: about 810 nm) having a spot shape elongated in the radial direction of the medium at 800 mW. The recording head was driven while performing automatic focusing so that the laser beam was focused on the recording film 14. The movement of the spot was shifted by 1/16 of the spot length in the radial direction of the medium. Thus, initial crystallization was performed. This initialization may be performed once, but when it is repeated three times, the rise in noise due to the initial crystallization can be reduced slightly. This initial crystallization has the advantage that it can be performed at high speed. Further, it is preferable that the initial crystallization be performed at a laser wavelength at which recording / reproducing is performed or at a wavelength close thereto (670 nm to 700 nm), since the laser power can be reduced.

[0304] These initial crystallizations may be performed in a drive having a semiconductor laser (wavelength 680 nm).
In this case, the medium is rotated at a linear velocity of 6 m / s, and the laser beam power is set to a level at which recording or erasing is not performed (about 1 mW).
) And the laser light is applied to the numerical aperture (N
A) was condensed by a 0.6 lens, and the recording film 14 was irradiated through the substrate 11. The reflected light from the recording film 14 was detected, tracking was performed, and the recording head was driven while performing automatic focusing so that the laser light was focused on the recording film 14. The laser beam irradiation is a continuous (DC) laser beam on the same recording track, and is crystallized twice (4 mW) at the level of amorphization (10 mW).
Was performed twice. Each irradiation time (light spot transit time)
Is about 0.18 μsec. When the laser beams having different powers are irradiated as described above, the initial crystallization can be sufficiently performed.

In the initialization, the light of the xenon lamp close to the point light source is condensed on a mask having a slit radially opened in the radial direction of the disk in the vicinity of the disk rotated by the ellipsoidal mirror. It may be performed by passing light. A slit having a width of 0.5 mm or more is preferable because initialization can be performed in a short time, and a slit of 3 mm or less is preferable because initialization power can be reduced. When the length of the slit is 5 mm or more, the initialization time can be reduced, and when it is 30 mm or less, the initialization power can be reduced, which is preferable. The distance between the disk and the slit is preferably 1 mm or less because the power can be reduced. This initialization is preferable because the initial crystallization can be completed only by rotating the medium a few times.

(Recording and erasing) Next, while performing tracking and automatic focusing on the recording area of the recording film 14 on which the initial crystallization has been completed as described above, the power of the recording laser beam is changed to the intermediate power level Pm ( 5mW) and the high power level Ph (10mW) to record information. The linear velocity of the recording track is 6 m / s, the wavelength of the semiconductor laser is 680 nm, and the numerical aperture (NA) of the lens is 0.6.
An amorphous portion or a portion close to the amorphous portion formed in the recording area by the recording laser beam is a recording point.

The power ratio between the high level and the intermediate level of the recording laser beam is particularly preferably in the range of 1: 0.3 to 1: 0.6. In addition, other power levels may be set for each short time. As shown in FIG. 7, during the formation of one recording mark, the power is repeatedly reduced to a level lower than the intermediate power level by a half (Tw / 2) of the window width, and
1 time to keep high power level at the beginning of recording mark formation
When recording is performed by a device having a means for generating a recording waveform in which the time width Tc of the cooling pulse for lowering the power Tw is 1 Tw, the distortion of the reproduced signal waveform is reduced, and a particularly low jitter value and error rate are obtained. Was done. In this drawing, only the recording waveforms of 4 Tw and 11 Tw are shown, but in the case of 5 Tw to 10 Tw, before the Tc of the 4 Tw waveform, the high power level and the low power level are Tw / 2, respectively.
The combination of waveforms to be kept is added one by one.
11 Tw is obtained by adding 7 sets to 4 Tw. 3 Tw
Is a recording waveform in which the time for maintaining the high power level at the beginning of the recording mark formation is 1.5 Tw. Recording was performed with the shortest recording mark length corresponding to 3 Tw being 0.62 μm or less. After passing through the portion to be recorded, the laser light power was reduced to the low power level Psl (1 mW) of the super-resolution reproduction (read) laser light.

In such a recording method, if new information is recorded by overwriting without erasing a portion where information has already been recorded, the information is rewritten with new information. That is, overwriting with a single substantially circular light spot is possible.

However, during the first rotation or multiple rotations of the disk at the time of rewriting, continuous light having the intermediate power level (5 mW) of the power-modulated recording laser light or a power (6 mW) close thereto is irradiated to perform recording. Information is erased once, and then between the low power level (1 mW) and the high power level (10 mW) or the intermediate power level (5 mW) and the high power level (10 mW) in the next rotation. In the meantime, recording may be performed by irradiating a laser beam whose power is modulated according to the information signal. As described above, if the information is erased before recording, the previously written information is less likely to be erased, and a particularly low jitter value can be obtained. Therefore, recording with the shortest recording mark length shorter than 0.62 μm is also facilitated.

These methods are effective not only for the recording film used for the medium of the present invention but also for the recording film of another medium.

In the case where the intermediate layer 15 was omitted from this disk, an increase in jitter was observed with the number of rewrites one digit less than the above. However, the increase in jitter was smaller than in the case where the intermediate layer 15 was omitted in the conventional structure disk.

(High-sensitivity super-resolution reading) Next, high-sensitivity super-resolution is performed on the recording area of the recording film 14 on which recording has been completed as described above, while performing tracking and automatic focusing in the same manner as described above. Irradiation was performed at the power level Ps (1 mW) of the reproducing (reading) laser beam, and information was read with high sensitivity and super-resolution. In the reading section, the laser power is changed between the level of Ps and half the power level to form a pulse, and after passing through the reading section, Ps
The level is fixed. Pulsing has the effect of appropriately maintaining the size of the aperture during super-resolution reproduction.

With the above method, the recording mark having the shortest mark length is read out with high sensitivity super-resolution, and the signal wave to noise ratio (C / C
N) was examined (FIG. 13). For comparison, a reproduction result was also shown for a conventional disk having no high-sensitivity super-resolution readout layer 26 in which recording was performed in a similar manner. This disc was reproduced at a conventional reproducing laser beam level Pr. From this, it can be seen that the C / N of the conventional disk decreases when the mark length is 0.4 μm or less, whereas the C / N of the disk of the present embodiment is large, and the reproduction characteristics are better than those of the conventional disk. By providing the high-sensitivity super-resolution readout film in this manner, the apparent spot diameter of the laser can be reduced, and a shorter recording mark can be reproduced. Further, the high-sensitivity super-resolution readout film described in the present embodiment has a high-sensitivity super-resolution reproduction power level Ps having a strength that does not significantly replace the conventional reproduction light level.
With no side effects such as deterioration of the recording film during super-resolution reproduction. Furthermore, even when the high-sensitivity super-resolution reading is repeated 105 times or more, the same reading characteristics as the initial one are obtained, and the number of times of super-resolution reading that can be read is greatly increased as compared with the conventional super-resolution reading disk. Was completed.

(Material for High Sensitivity Super Resolution Readout Layer) The mask layer 26 for high sensitivity super resolution read out, [(SiO 2) 71
(Na2O) 14 (CaO) 8 (MgO) 6 (Al2O3) 1]
As a material instead of 80 [(Co3 O4)] 20, [(S
iO2) 71 (Na2O) 14 (CaO) 8 (MgO) 6 (Al
Materials having different [(Co3O4)] ratios to [2O3) 1] may be used. The more (Co3 O4), the more C /
N increases. Further, (Co3O4) is replaced with CoO, Co2
O3, a mixture thereof, or a composition having a different ratio of metal to oxygen may be used. Further, a transition metal oxide in which Co is replaced by another transition metal element, a mixture thereof, or an oxide having a composition close to this may be used. Of these, Fe oxides and Ni oxides are more preferable because the change in transmittance during laser irradiation is large. Co oxide is particularly preferable because it has a larger change in transmittance.

On the other hand, [(SiO 2) 71 (Na 2 O) 14
(CaO) 8 (MgO) 6 (Al2O3) 1]
2), (Na2O), (CaO), (MgO), (Al2O)
O3) may be replaced with a material having a different composition ratio. In this case, it is more preferable that the SiO2 content be 50% or more of the whole, since the transmittance change during laser irradiation is large. Furthermore, Si
O2, [(SiO2) 72 (Na2O) 16 (CaO) 12 (L
a2O3) 53 (B2O3) 37 (ZrO2) 6 (Ta2O5)
5], B2O3, P2O5, GeO2, As2O3, Li2O-
SiO2, Na2O-SiO2, K2O-SiO2, MgO
-SiO2, CaO-SiO2, BaO-SiO2, Pb
O-SiO2, Na2O-CaO-SiO2, Al2O3-
SiO2, Li2O-B2O3, Na2O-B2O3, K2O-
B2O3, MgO-B2O3, CaO-B2O3, PbO-
B2O3, Na2O-CaO-B2O3, ZnO-PbO-
B2O3, Al2O3-B2O3, SiO2-B2O3, Li2O
-P2O5, Na2O-P2O5, MgO-P2O5, CaO
-P2O5, BaO-P2O5, ZnO-BaO-P2O5,
Al2O3-P2O5, SiO2-P2O5, B2O3-P2O
5, V2O5-P2O5, Fe2O3-P2O5, WO3-P2O
5, Li2O-GeO2, Na2O-GeO2, K2O-G
eO2, B2O3-GeO2, SiO2-GeO2, Na2O
-WO3, K2O-WO3, Na2O-MoO3, K2O-M
oO3, Li2O-MoO3, Na2O-TeO2, Na2O
-B2O3-SiO2, Na2O-Al2O3-SiO2, C
aO-Al2O3-SiO2, Na2O-Al2O3-B2O3
-SiO2, BeF2, NaF-BeF2, ZrF4-Ba
F2-ThF4, GdF3-BaF2-ZrF4, Al (P
Similar characteristics can be obtained by changing to a material having a composition close to O3) -AlF3-NaF-CaF2, inorganic glass, or a mixture thereof.

In addition, it is preferable to add a rare earth element or oxide and optimize the amount, because the apparent spot diameter can be optimized by narrowing it. The addition amount is preferably 1 atomic% or more and 30% or less.

(Film Forming Method) The mask layer 26 for high-sensitivity super-resolution reading was formed by sputtering, but it may be formed by vacuum evaporation. Sputtering has the disadvantage that the film-forming equipment including the apparatus is expensive, but the uniformity of the film is good. Vacuum deposition has inferior film uniformity to sputtering, but has the advantage that the film forming equipment is inexpensive. These sputter sources or vapor deposition sources are preferably made of a target or a vapor deposition base material having a composition close to the composition of the high-sensitivity super-resolution readout mask layer. In addition, similar characteristics can be obtained even when a film is formed from a plurality of targets or deposition base materials having different compositions. In addition to using a target having a composition close to the composition of the mask layer for high-sensitivity super-resolution reading, a target in which chips having different compositions are attached to one target may be used. In this case, the composition stability in performing a large number of sputterings is low, but there is an advantage that the composition adjustment is simple.

Further, it is preferable to provide the following film forming means because the laser beam can be easily focused during recording / reproducing.

FIGS. 14A and 14B schematically show the substrate.

FIGS. 15A to 15D show a part of the creation process. As shown in FIG. 15 (a), when a film is formed on the recording / reproducing area 30 in the substrate of FIG. 14 (b), a part or all of an area 29 for focusing a laser beam during recording / reproducing. Is covered with a mask 31 to form a film. In FIG. 15A, the mask material 3 for high-sensitivity super-resolution reading is shown.
2 is deposited on the substrate. In this way, a place where the high-sensitivity super-resolution readout mask layer 33 is not formed is formed on the area 29 where the laser beam is focused during recording / reproduction. Next, as shown in FIG.
Then, another layer including the reflective layer is formed. FIG.
In (c), a material 34 such as a reflective layer is deposited on the substrate. As a result, the layer 35 including the reflective layer is laminated on the area 29 for focusing the laser beam during recording / reproduction without the mask layer 33 for high-sensitivity super-resolution reading. This portion has a higher reflectance than the portion stacked via the high-sensitivity super-resolution readout mask layer 33. For this reason,
Easy to focus laser light.

Items not described in this embodiment are described in Embodiment 1.
Same as 0-12.

Embodiment 14 (Structure, Manufacturing Method) FIG. 12 shows a cross-sectional structure of a disc-shaped information recording medium using an information recording thin film using a high-sensitivity super-resolution readout mask layer 26 of this embodiment. This medium is
On a polycarbonate substrate 23 having a diameter of 12 cm and a thickness of 0.6 mm on which information was recorded on the surface in an uneven manner, [(SiO 2) 71 (Na 2 O) 14 (Ca 2)
O) 8 (MgO) 6 (Al2O3) 1] 80 [(Co3O4)] 2
High sensitivity super resolution readout layer 26 consisting of 0, film thickness about 50 nm
The reflection layer 27 made of the Al97Ti3 film was laminated. A protective coating layer 18 was provided thereon.

(Material of Reflection Layer) Al97Ti3 of the reflection layer 27
Al-Ti, Al-Ag, A
Those containing an Al alloy as a main component such as l-Cu, Al-Cr, and Al-Co are preferable. Al can also be used. Since the Al alloy is soft, there is an advantage that interfacial peeling or the like due to internal stress does not easily occur.

In the case of an Al alloy, the reflectivity can be increased when the Al content is 50 atomic% or more and 99.9 atomic% or less.
N is good.

In addition, other Al alloys, Au, Ag,
Cu, Al, Ni, Fe, Co, Cr, Ti, Pd, P
t, W, Ta, Mo, Sb, Bi, Dy, Cd, Mn,
Mg, V element simple substance, Au alloy, Ag alloy, Cu
Alloys, Pd alloys, Pt alloys, Sb-Bi, SUS (stainless steel), Ni-Cr, and other alloys containing these as main components, or layers composed of alloys of these alloys may be used. May be used, a composite layer of these with another substance such as an oxide, a composite layer of these with another substance such as another metal, or the like may be used. This has a similar effect.

Further, compared to Au alone, Au-Ag, A
Au alloys such as u-Co and Au-Al are preferred because they have the advantage of increasing the adhesive strength.

In addition, any material having a reflectance of 40% or more may be used. The extinction coefficient k of the material is preferably 3 or more.

The thickness of the reflective layer is at least 30 nm from the viewpoint of increasing the reflectance, and is 200 nm from the viewpoint of reducing the production time.
The following is more preferred. More preferably, the thickness is 50 nm to 100 nm.

Items not described in this embodiment are described in Embodiment 1.
Same as 0-13.

[0330]

As described in detail above, in the information recording medium of the present invention, the reflectivity is set to 15% or more, which is sufficient for tracking servo and focus servo, and the reproduction signal modulation is set to 50% or more. Can be. In addition, since a plurality of reflective layers are provided, optical requirements can be satisfied by reflection of the first reflective layer, and thermal characteristics can be satisfied by heat conduction by other reflective layers.

In particular, when the composition of the first reflection layer is Al, Cu, A
When g, Au, Pt, and Pd are the main components, and the sum of the composition ratios of these atoms is 70% or more and 85% or less, the thermal conductivity is 1/10 or less as compared with the case where the metal is used alone. Therefore, the recording sensitivity at the time of recording is improved.

[0332] Among these high reflectivity metals, A
l is relatively inexpensive because the reflectance has a small dependence on the light wavelength,
The most excellent point is that the thermal conductivity can be easily reduced by a small amount of additives.

A second reflection layer having a composition different from that of the first reflection layer is provided on the side opposite to the light incident side of the first reflection layer, and the composition of the second reflection layer has a higher thermal conductivity than that of the first reflection layer. By setting the rate and the strength to be high, it is possible to provide an information recording medium which has a high effect of suppressing thermal interference between marks during recording, has good reproduction signal quality, and has high mass productivity.

Further, since the first reflective layer having a relatively low thermal conductivity is provided between the second reflective layer having a high thermal conductivity and the intermediate layer, the total thickness of the reflective film can be reduced without lowering the recording sensitivity. Can be thicker. As a result, an information recording medium having a high recording film flow suppression effect can be provided.

Also, the third reflective layer having a higher reflectance than the first reflective layer can be used.
By providing the reflective layer between the intermediate layer and the first reflective layer, the optical characteristics of the information recording medium, such as the reflectance and the degree of modulation, are further improved.

When a non-metal layer having a low thermal conductivity is provided between the first reflective layer and the second reflective layer, the thermal characteristics are further improved, the recording sensitivity is improved, and the thermal interference between recording marks is reduced. Can be suppressed.

Further, the present invention relates to an information recording medium of a system (land / groove recording system) in which a groove is provided on a transparent substrate and recording marks are recorded both in the groove (groove) and between the grooves (land). Is especially effective. Track pitch is energy beam diameter (when laser beam is used as energy beam, it corresponds to λ / NA, when laser wavelength is λ, and when numerical aperture of objective lens for focusing laser on information recording medium is NA, it is λ / NA ), It is possible to realize high-density recording in which cross-erase does not occur.

Further, in the information recording medium of the present invention, the influence of thermal interference between marks during recording is suppressed as much as possible, so that even when mark edge recording is performed, the length of the recording mark is adjusted to an appropriate length. It becomes possible to control.

When used in a method of recording information by irradiating a laser beam of a certain level and modulating the direction of an external magnetic field (magnetic field modulation recording method) as typified by a magneto-optical disk. Although the information recording medium of the present invention is suitable for the above method, a particularly great effect is exhibited when the information recording medium is used in a system for recording information by modulating the power level of an energy beam (laser beam) (light intensity modulation system). I do. That is, in the case of light intensity modulation recording, in a normal information recording medium, since heat is easily transmitted on the recording layer plane, this heat is applied to the shape of a recording mark recorded before or the shape of a recording mark recorded later. Although the influence is likely to occur (thermal interference), in the information recording medium of the present invention, since heat is selectively diffused from the first reflective layer to the second reflective layer, it is possible to minimize the thermal diffusion on the recording layer plane. Because you can.

Further, in the phase change recording method, generally, the recording film tends to flow or change in shape at the time of rewriting many times, but in the information recording medium of the present invention, these deteriorations can be easily suppressed. .

Also, by using a recording layer having a composition suitable for the information recording medium of the present invention, video information compressed by a video compression method such as MPEG2 or equivalent data can be obtained.
This makes it possible to record information on the data transfer rate.

Further, by combining the above-mentioned information recording / reproducing apparatus with the information recording medium of the present invention, high-density recording is possible, a good quality reproduction signal is obtained, and reproduction of a read-only optical disc is also possible. A simple information recording and reproducing system is realized.

Further, as described above, according to the information recording medium of the present invention, while maintaining good recording / reproducing characteristics or good super-resolution reading characteristics, the number of times of rewriting or super-resolution Image readout becomes possible.

According to the information recording / reproducing apparatus of the present invention, good recording / reproducing characteristics or good super-resolution reading characteristics can be obtained even after rewriting has been performed a number of times with the information recording medium of the present invention. .

[Brief description of the drawings]

FIG. 1 is a structural diagram of an information recording medium of the present invention.

FIG. 2 is a block diagram of an information recording / reproducing apparatus used in the information recording / reproducing system of the present invention.

FIG. 3 is a structural diagram of an information recording medium of the present invention.

FIG. 4 is a structural diagram of an information recording medium of the present invention.

FIG. 5 is a structural sectional view of an information recording medium according to one embodiment of the present invention.

FIG. 6 is a structural sectional view of an information recording medium having a conventional structure.

FIG. 7 shows a recording waveform used for evaluating the recording / reproducing characteristics of the information recording medium of the present invention.

FIG. 8 shows the rewriting characteristics of the information recording medium of one embodiment of the present invention and the information recording medium of the conventional structure.

FIG. 9 shows the wavelength dependence of the reflectance of the information recording medium according to the first embodiment of the present invention and the information recording medium having a conventional structure.

FIG. 10 shows the wavelength dependence of the reflectance of the reflective layer, the intermediate layer, and the reflective layer of the information recording medium of one embodiment of the present invention and the information recording medium of the conventional structure.

FIG. 11 is a structural sectional view of an information recording medium according to another embodiment of the present invention.

FIG. 12 is a structural sectional view of an information recording medium according to another embodiment of the present invention.

FIG. 13 shows reproduction characteristics of an information recording medium according to another embodiment of the present invention and an information recording medium having a conventional structure.

FIG. 14 schematically shows an information recording medium according to another embodiment of the present invention.

FIG. 15 shows a part of a process of manufacturing an information recording medium according to another embodiment of the present invention.

[Explanation of symbols]

1: information recording medium 2: motor 3: optical head 4:
Preamplifier circuit 6: Recording waveform generation circuit 7: Laser drive circuit 8: 8-
16 modulator 9: L / G servo circuit 10: 8-16 demodulator. 1
1, 11 ': polycarbonate substrate 12, 12': first protective layer 13, 13 ': first protective layer 14, 14': recording film 15, 15 ': intermediate layer 16, 16': first reflective layer 17, 17 ': Second reflective layer 18, 18': Protective coating layer 19: Adhesive layer T: Window width (Tw) Pr: Low power level
Pm: Intermediate power level Ph: High power level Tc: Time to decrease at the end of recording pulse 23: Substrate having recording pits formed in irregularities 24, 24 ': Super-resolution reading film 25: Recording pit 26, 26' : High-sensitivity super-resolution readout layer 27: Reflective layer 28: Substrate 29: Lead-in area 30: Recording area 31:
Mask 32: High-sensitivity super-resolution readout layer material 33: High-sensitivity super-resolution readout layer partially formed on a substrate 34: Reflective layer material 35: Reflective layer partially formed directly on a substrate .

Continued on front page (72) Inventor Motoyasu Terao 1-280 Higashi Koikekubo, Kokubunji-shi, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Yukio Fukui 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Picture of Hitachi, Ltd. Information Media Division (72) Inventor Nobuhiro Tokujuku 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Hitachi, Ltd.Video Information Media Division (72) Inventor Yasushi Miyauchi 1-280-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo Shares (72) Inventor Keikichi Ando 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Tokyo, Japan Inside (72) Tetsuya Nishida 1-280 Higashi Koigakubo, Kokubunji-shi, Tokyo Hitachi, Ltd. Central Research Laboratory (72) Inventor Koichi Moriya 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Pref. Multimedia Systems Development Division, Hitachi, Ltd.

Claims (67)

[Claims] An information recording thin film on which information (recording mark) is recorded by a change in an atomic arrangement and / or a change in an electronic state by irradiation of an energy beam is provided as a recording layer, and the recording mark recorded on the recording layer is provided. An information recording medium reproduced by energy beam irradiation, comprising at least a first reflection layer and a second reflection layer having different compositions on a side opposite to an energy beam incident side of the recording layer. The composition of the first reflective layer located on the side
An information recording medium comprising l, Cu, Ag, Au, Pt, and Pd as main components, and the sum of the content of these atoms is 60% or more. 2. The information recording medium according to claim 1, wherein said recording medium is Al, Cu, Ag, Au, Pt, P
An information recording medium comprising d and Mo as main components and having a second reflective layer having a sum of the contents of these atoms larger than the sum of the contents of these atoms in the first reflective layer. 3. The information recording medium according to claim 1, wherein
An information recording medium comprising a first reflective layer containing 65% or more and 95% or less of Al. 4. The information recording medium according to claim 1, wherein said first reflective layer is made of Ti, Cr, Co, Ni, M
g, Si, V, Ca, Fe, Zn, Zr, Nb, Mo,
An information recording medium, characterized in that at least one element selected from the group consisting of Rh, Sn, Sb, Te, Ta, W, Ir, Pb, B and C is added to the main component. 5. The information recording medium according to claim 1, wherein said first reflective layer has a thickness of 30 nm or more and 300 nm or less. 6. The information recording medium according to claim 5, wherein:
An information recording medium comprising a second reflective layer containing 90% or more of Al. 7. The information recording medium according to claim 5, wherein said second reflective layer has a thickness of 50 nm or more and 250 nm or more.
m or less. 8. The information recording medium according to claim 1, further comprising a transparent substrate at least on the energy beam incident side, and between the transparent substrate and the first reflection layer. An information recording medium comprising two protective layers, a first protective layer and an intermediate layer, and a recording layer between the first protective layer and the intermediate layer. 9. The information recording medium according to claim 8, wherein:
An information recording medium, characterized in that at least one of the first protective layer and the intermediate layer contains Zn and S. 10. The information recording medium according to claim 9, wherein, of the first protective layer and the intermediate layer, the thickness of the first protective layer near the transparent substrate is 50 nm or more and 100 nm or less, An information recording medium, wherein the thickness of the recording layer is 5 nm or more and 30 nm or less, and the thickness of the intermediate layer is 10 nm or more and 40 nm or less. 11. The information recording medium according to claim 10, further comprising a second protective layer containing a compound of Al and O between the first protective layer and the recording layer. . 12. The information recording medium according to claim 11, wherein said second protective layer has a thickness of 2 nm or more and 20 nm or less. 13. The information recording medium according to claim 8, wherein the sum of the thicknesses of the first reflective layer and the second reflective layer is 130 n.
An information recording medium having a length of at least m and at most 400 nm. 14. The information recording medium according to claim 8, wherein Al, Cu, A is provided between said first reflection layer and said recording layer.
An information recording medium comprising g, Au, Pt, and Pd as main components, and having a third reflective layer in which the sum of the contents of these atoms is larger than the first reflective layer. 15. The information recording medium according to claim 14, further comprising a third reflective layer containing 90% or more of Al. 16. The information recording medium according to claim 14, wherein the first reflection layer and the third reflection layer are adjacent to each other, and the thickness of the third reflection layer is 30 nm or less. Information recording medium. 17. The information recording medium according to claim 8, wherein a thickness between the first reflection layer and the second reflection layer is 200 nm.
An information recording medium having the following non-metal layer. 18. The information recording medium according to claim 1, further comprising a substrate provided with a groove, wherein said substrate has a groove.
An information recording medium, characterized in that an address information mark is provided for recording a recording mark in both the groove and the land (land). 19. An information recording medium according to claim 1, wherein said information recording medium is recorded by a method of recording a recording mark of a plurality of lengths corresponding to an information signal. Information recording medium. 20. An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on said replaceable information recording medium, wherein an atomic arrangement changes by irradiation of an energy beam, and / or An information recording medium comprising, as a recording layer, an information recording thin film on which information (recording mark) is recorded by a change in electronic state, wherein the recording mark recorded on the recording layer is reproduced by energy beam irradiation. A first reflective layer and a second reflective layer having different compositions are provided on the side opposite to the energy beam incident side of the recording layer, and the composition of the first reflective layer located closer to the recording layer is Al, Cu, Ag. , Au, Pt, and Pd as main components, and the sum of the contents of these atoms is 60% or more, and a recording mark is formed on the information recording medium. An information recording / reproducing apparatus comprising: a laser beam irradiating means for addressing; and address information detecting means for detecting address information from an electric signal obtained by reproducing an address information mark provided on the information recording medium. An information recording / reproducing system characterized by the following. 21. An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on said replaceable information recording medium, wherein an atomic arrangement changes by irradiation of an energy beam, and / or An information recording medium comprising, as a recording layer, an information recording thin film on which information (recording mark) is recorded by a change in electronic state, wherein the recording mark recorded on the recording layer is reproduced by energy beam irradiation. A first reflective layer and a second reflective layer having different compositions are provided on the side opposite to the energy beam incident side of the recording layer, and the composition of the first reflective layer located closer to the recording layer is Al, Cu, Ag. , Au, Pt, and Pd as main components, and the sum of the contents of these atoms is 60% or more, and a recording mark is formed on the information recording medium. An information recording / reproducing apparatus having a recording signal modulation circuit and a reproduction signal demodulation circuit for performing recording by a method of recording a recording mark of a plurality of lengths corresponding to an information signal. An information recording / reproducing system characterized by the following. 22. The system according to claim 21, wherein:
A laser having a light wavelength of 600 to 700 nm is used as an energy beam for recording mark recording with a lens numerical aperture of 0.56.
A laser beam condensed by an objective lens having a length of 0.66 or less is used, and the shortest recording mark length among the plurality of lengths of the recording marks is 0.2 to 0.7 μm. Information recording and playback system. 23. The system according to claim 21, wherein:
A laser beam irradiating means for condensing a laser having a light wavelength of 600 to 700 nm by an objective lens having a lens numerical aperture of 0.56 or more and 0.66 or less; An information recording / reproducing system comprising an information recording / reproducing device having a recording waveform generating circuit for controlling an energy beam irradiation time for recording a shortest recording mark so as to be 2 μm or more and 0.7 μm or less. 24. The information recording medium according to claim 1, wherein recording is performed with at least a first power level and a second power level as a power level of the energy beam, and An information recording medium, comprising: a recording layer that changes to a first state by irradiation at a power level of 2 and to a second state by irradiation at a second power level. 25. An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on the replaceable information recording medium, wherein the information recording medium according to claim 24, The power level of the energy beam is the first
An information recording / reproducing system, comprising: an information recording / reproducing device having a power level modulation circuit for modulating between a power level of the first and second power levels. 26. The information recording medium according to claim 1, wherein the first power level is a second power level.
An information recording medium, wherein the first state is an amorphous state and the second state is a crystalline state. 27. An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing device for recording information on said replaceable information recording medium, wherein the information recording medium according to claim 26, The power level of the energy beam is the first
An information recording / reproducing system, comprising: an information recording / reproducing device having a power level modulation circuit for modulating between a power level of (i) and a second power level lower than the first power level. 28. The information recording medium according to claim 26, wherein at least Ge, Sb, and Te are main components, and Ge,
Sb, Te, Ag, In, Co, Se, Ti, Cr, N
i, Mg, Si, V, Ca, Fe, Zn, Zr, Nb,
Mo, Rh, Sn, Ta, W, Ir, Pb, B and C
And at least one additional element M selected from the group consisting of: (Ge2Sb2Te5)
An information recording medium comprising a recording layer satisfying (1−x) + Mx (where 0.015 <x <0.20). 29. An information recording / reproducing system comprising a replaceable information recording medium and an information recording / reproducing apparatus for recording information on the replaceable information recording medium, wherein the information recording medium according to claim 28, The power level of the energy beam is the first
An information recording / reproducing system, comprising: an information recording / reproducing device having a power level modulation circuit for modulating between a power level of (i) and a second power level lower than the first power level. 30. An information recording medium according to claim 1, wherein the level of a reflected light level upon irradiation with an energy beam is converted into an electric signal to reproduce the information. Is performed, using an energy beam defined in the standard for recording and reproduction of the information recording medium, the information recording medium in the width of less than half the width of the energy beam, 1 times or more Reflected light level Rr from an amorphous recording mark recorded in length
And the ratio (Rr / Rn) of the reflected light level Rn from the portion where no recording mark is recorded (crystal state) is 0.5 or less,
Or, an information recording medium characterized by being 2.0 or more. 31. An information recording / reproducing system comprising a replaceable information medium and an information recording / reproducing apparatus for reproducing the replaceable information medium, wherein the information recording medium and the read-only information medium according to claim 30 are provided. 31. At least two types of information media and energy beam irradiation means for irradiating an energy beam, and photoelectric conversion for converting the level of light reflected from the information recording medium and read-only information medium according to claim 30 into an electric signal. An information recording / reproducing system comprising an information recording / reproducing device having means. 32. The information recording medium according to claim 30, wherein the highest reflected light level Rh is 15 to 24%.
An information recording medium, characterized in that: 33. An information recording / reproducing system comprising an exchangeable information medium and an information recording / reproducing apparatus for reproducing the exchangeable information medium, wherein the information recording medium and the read-only information medium according to claim 32 are provided. 33. An energy beam irradiating means for irradiating at least two kinds of information media and an energy beam, and photoelectric conversion for converting a level of a light reflected from an information recording medium and a read-only information medium according to claim 32 into an electric signal. An information recording / reproducing system comprising an information recording / reproducing device having means. 34. The information recording medium according to claim 8, further comprising a second protective layer between said first protective layer and said recording layer, wherein said second protective layer is an oxide, nitride or fluoride. An information recording medium, which is one of the above. 35. The information recording medium according to claim 34, wherein the thickness of the second protective layer is 2 nm or more and 20 nm or less. 36. The information recording medium according to claim 34, further comprising a second intermediate layer between said intermediate layer and said recording layer, wherein said second intermediate layer is any one of an oxide, a nitride and a fluoride. An information recording medium characterized in that: 37. An information recording thin film, which is formed on a substrate directly or through an underlayer and records and / or reproduces information by a change in atomic arrangement caused by irradiation with an energy beam, as a recording layer, and A protective layer, and the reflective layer is composed of at least a first reflective layer and a second reflective layer of a material having at least one of a different refractive index or extinction coefficient, and is laminated in the order of a protective layer and a recording layer from the light incident side;
An information recording medium having a structure in which a first reflective layer and a second reflective layer are stacked in this order directly or via another layer. 38. The difference between the refractive index and the extinction coefficient of the first reflective layer and the second reflective layer is 0.5 or more, and at least the refractive index or the extinction coefficient of the first reflective layer and the second reflective layer. 38. The difference of one of claims 1 or 37, wherein one difference is 2 or less.
An information recording medium according to claim 1. 39. The refractive index of the first reflective layer is 5 or less, the refractive index of the second reflective layer is 2 or less, and the extinction coefficient of the first reflective layer is 5 or less, or the refractive index of the second reflective layer is 5 or less. The information recording medium according to claim 1 or 37, wherein an extinction coefficient is 5 or more. 40. The information recording medium according to claim 1, further comprising a third reflective layer on the recording layer side of both the first reflective layer and the second reflective layer. 41. The information recording medium according to claim 40, wherein the thickness of the third reflection layer is smaller than the thickness of any of the first reflection layer and the second reflection layer. 42. A component which accounts for 90% or more of the total number of atoms of the second reflection layer is made of Al-Ti, Al-Ag, Al-Cu, Al-C.
38. The information recording medium according to claim 1, comprising at least one of r and Al-Co. 43. A component which accounts for 90% or more of the total number of atoms of the second reflection layer is at least one of Al, Au, Cu and Mo.
The information recording medium according to claim 1 or 37, comprising: 44. The information recording medium according to claim 1, wherein a component of 95% or more of the total number of atoms of the recording film is made of Ge-Sb-Te. 45. A composition in which 90% or more of the total number of atoms of the recording film is composed of 1 to 5 atomic% of Ag, 17 to 25 atomic% of Ge, 19 to 25 atomic% of Sb, and 53 of Te. ~ 5
38. The information recording medium according to claim 1, wherein the content is in the range of 9 atomic%. 46. A recording film wherein 90% or more of the total number of atoms is composed of 2 to 20% of a material having a composition close to AgSbTe2;
38. The information recording medium according to claim 1, wherein the balance is made of a material having a composition close to Ge2Sb2Te5. 47. The information recording medium according to claim 1, wherein the first reflection layer is directly laminated on the recording film. 48. The information recording medium according to claim 1, further comprising an intermediate layer between the recording layer and the first reflection layer. 49. The information recording medium according to claim 48, wherein 90% or more of the total number of atoms in said intermediate layer is made of ZnS. 50. The intermediate layer comprises two layers: a film in which 90% or more of all atoms are composed of ZnS and a film in which 90% or more of all atoms are composed of Al oxide. 49. The information recording medium according to claim 48. 51. The information recording medium according to claim 48, wherein a component of 10 atomic% or more and 40 atomic% or less of the total number of atoms of said intermediate layer has an Al—O composition. 52. A composition in which 90% or more of the total number of atoms of the intermediate layer is (ZnS)-(Al2O3), (ZnS)-(Al2
49. The information recording medium according to claim 48, wherein the information recording medium has a composition close to at least one of O3)-(SiO2). 53. The information recording medium according to claim 37, wherein a component of 10 to 40 atomic% of the total number of atoms of the protective layer is made of Al—O. 54. A first protective layer in which the protective layer comprises 90% or more of the total number of atoms of ZnS and a second protective layer wherein 90% or more of the total number of atoms comprises Al-O or Al-Si-O. The information recording medium according to any one of claims 8 and 37, comprising a protective layer. 55. The semiconductor device according to claim 55, wherein the protective layer comprises Al--O or Al
55. The information recording medium according to claim 54, wherein the thickness of the -Si-O film is 2 nm or more and 20 nm or less. 56. A composition in which 90% or more of the total number of atoms of the protective layer is (ZnS)-(Al2O3), (ZnS)-(Al2
38. The information recording medium according to claim 8, wherein the information recording medium has a composition close to at least one of O3)-(SiO2) and (Al2O3)-(SiO2). 57. The recording film has a thickness of 10 nm or more and 30 n or more.
m or less.
8. The information recording medium according to any one of 7. 58. A film thickness of said protective layer is not less than 60 nm and not more than 110.
38. The information recording medium according to claim 1, wherein the information recording medium is in a range of not more than nm. 59. The intermediate layer having a thickness of 15 nm or more and 30 n or more.
53. The range of not more than m.
The information recording medium according to any one of the above items. 60. The film thickness of the first reflection layer is 50 nm or more.
38. The information recording medium according to claim 1, wherein the information recording medium is in a range of not more than 00 nm. 61. A film thickness of the second reflection layer is 50 nm or more.
The information recording medium according to any one of claims 1 to 37, wherein the information recording medium is in a range of 50 nm or less. 62. The information recording medium according to claim 1, further comprising an inorganic super-resolution readout layer on the side of the protective layer opposite to the recording film. 63. The information recording medium according to claim 37, further comprising an inorganic super-resolution readout layer at one of the interfaces of each of the layers. 64. The information recording medium according to claim 37, further comprising an inorganic super-resolution readout layer between said protective layers. 65. An information recording medium, comprising: a mask layer for super-resolution reading of an inorganic substance formed directly or via an underlayer on a substrate on which information is recorded with unevenness. 66. An information recording thin film which is formed on a substrate directly or through an underlayer and records and / or reproduces information by a change in atomic arrangement caused by irradiation of an energy beam, as a recording film or super-resolution. An information recording medium provided as a read mask layer and provided with a reflective layer and having a minimum reflectance in a crystalline state and / or an amorphous state in a wavelength range of 400 nm to 800 nm. 67. A recording film comprising: an information recording thin film formed on a substrate directly or through an underlayer, for recording and / or reproducing information by a change in atomic arrangement caused by irradiation with an energy beam; and An information recording medium comprising a reflective layer and having a difference between a maximum value and a minimum value of 20% or more in a wavelength range of 400 nm or more and 850 nm or less in reflectance of the reflective layer when light is incident from the recording film side.