JP2002237088A - Optical information recording medium and method for recording onto the medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rewritable optical information recording medium which has the same capacity with that of a DVD-ROM and has excellent recording characteristics in high-linear-speed recording and superior storage stability, and to provide a method for recording onto the medium. SOLUTION: On a transparent substrate 1, a 1st dielectric layer 2, a phase change recording layer 3, a 2nd dielectric layer 4, and a metal reflecting layer 6 are deposited by sputtering in this order and a 3rd dielectric layer 5 is deposited of a material other than sulfide between the 2nd dielectric layer and the metal reflecting layer. When optical information is recorded on the thus obtained optical information recording medium, a recording pulse train of a plurality of on pulses and off pulses is used as the emission waveform of laser beam and the recording frequency is varied continuously from the inner periphery to the outer periphery or vice versa according to a recording radial position; and parts where the widths of the on pulses are all fixed with the same time constant and parts where a window width is multiplied by a constant are successively combined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium and a recording method for the medium.
The present invention relates to a phase-change optical information recording medium capable of causing an optical change in a recording layer material by irradiating a light beam, recording and reproducing information, and rewritable, and a recording method for the medium.

[0002]

2. Description of the Related Art As one of optical information recording media capable of recording, reproducing and erasing information by irradiating a laser beam,
2. Description of the Related Art A so-called phase-change optical information recording medium utilizing a transition between a crystal and an amorphous phase or a transition between a crystal and a crystal phase is known. This is characterized by being capable of overwriting with a single beam and being simpler than the optical system on the drive side, and has been applied as a computer-related or recording medium for video and audio.

The recording materials include GeTe, GeT
eSe, GeTeS, GeSeS, GeSeSb, Ge
AsSe, InTe, SeTe, SeAs, Ge-Te
-(Sn, Au, Pd), GeTeSeSb, GeTe
Sb, Ag-In-Sb-Te and the like are used. Among them, particularly, Ag-In-Sb-Te has a feature of high sensitivity and a clear outline of an amorphous portion, and C / N, erasing ratio, sensitivity, and recording. JP-A-8-22644 discloses a composition of an optical information recording medium capable of achieving a dramatic improvement in the erasure repetition characteristics.

The constituent elements of this recording layer are mainly A
g, In, Sb, and Te, and their respective composition ratios α,
β, γ, and δ (atomic%) have the following relationship. 0 <α ≦ 30 0 <β ≦ 30 10 ≦ γ ≦ 50 10 ≦ δ ≦ 80 α + β + γ + δ = 100

[0005] In particular, as an application to a rewritable compact disc (CD) using this material system,
The rotational linear velocity of the disk is from 1.2 m / s to 5.6 m / s
In the recording method of performing recording and erasing in the area of No. 1, the constituent elements of the recording layer of the medium are mainly Ag, In, Te, and Sb as the optimum optical information recording medium, and the respective composition ratios α, β, and γ , Δ (atomic%) has an optical information recording medium having a relationship represented by the following formula: Japanese Patent Application Laid-Open No. 9-263055. 1 ≦ α <67 7 ≦ β ≦ 20 20 ≦ γ ≦ 35 35 ≦ δ ≦ 70 α + β + γ + δ = 100

In the current optical disk, a 4.7 GB capacity DVD-ROM has already been commercialized, and a high recording density medium such as a DVD-RW has been proposed as an optical information recording medium having the same capacity and high compatibility. I have. Since the disk rotation speed of the DVD-ROM is 3.49 m / s, a recording material used for an optical information recording medium having a constant speed is disclosed in Japanese Patent Laid-Open No. 9-263.
The composition disclosed in Japanese Patent No. 055 can also be used. However, experiments have shown that it is difficult to realize a recording medium that has the same capacity as a DVD-ROM and has a high-density recording and a recording linear velocity of 2 × or more (about 7 m / s or more).

[0007]

SUMMARY OF THE INVENTION The present invention relates to a DVD-R
A rewritable optical information recording medium having the same capacity as the OM, which has good recording characteristics at high linear velocity recording and excellent storage stability, and a recording method for this medium. It is an object of the present invention to provide

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have focused on the composition of the recording layer, the constituent metal of the metal reflective layer and the dielectric layer, and as a result of intensive studies, have found that The invention has been completed.

That is, according to the present invention, first, a first dielectric layer, a phase change recording layer, a second dielectric layer, and a metal reflection layer are formed on a transparent substrate by sputtering in this order, First
The material of the second dielectric layer is a mixture of ZnS and SiO _2, and the composition of the material of the phase change recording layer is Ag _a In _b Sb _c T
An optical information recording medium with e _d, the composition Ag _a an In _b
To sb _c Te _d, with the addition of element X _e other than said set forming component, the metal reflective layer and Ag or an Ag alloy, other than sulfide between the second dielectric layer and the metal reflective layer An optical information recording medium characterized by comprising a third dielectric layer made of a material [where a, b, c, and d are represented by the following formula (1):
４ (4), and when c / (c + d) is r, cd is assumed to be in the following equation (5)]. 0 <a ≦ 0.01 (1) 0.03 ≦ b ≦ 0.10 (2) 0.40 ≦ d ≦ 0.70 (3) a + b + c + d = 1 (4) 0.60 ≦ r ≦ 0.85 ( 5)

[0010] The first invention includes an optical information recording medium in which the element Xe is Ge [provided that the amount of addition e has a relationship represented by the following formula (6)]. 0.005 ≦ e ≦ 0.07 (6)

Further, according to the first invention, the thickness ratio of the second dielectric layer to the first dielectric layer (R1 = second dielectric layer thickness / first dielectric layer thickness) is as follows: The optical information recording medium having the relationship of the following equation (7) is included. 0.1 ≦ R1 ≦ 0.5 (7)

Further, the first invention includes an optical information recording medium in which the thermal conductivity of the third dielectric layer is higher than the thermal conductivity of the second dielectric layer.

In the first invention, the thickness ratio of the third dielectric layer to the second dielectric layer (R2 = third dielectric layer thickness / second dielectric layer thickness) may be as follows: The optical information recording medium having the relationship of the following equation (8) is included. 0.1 ≦ R2 ≦ 0.5 (8)

The first invention further provides an optical information recording medium in which the material of the third dielectric layer is a metal carbide or a mixture of a metal carbide and a metal oxide or a metal nitride. An optical information recording medium in which the metal is Si and the metal of the metal oxide or metal nitride is Si, Ti or Al is included.

According to the present invention, secondly, in recording optical information on the optical information recording medium according to any of the above,
Optical information to be recorded by changing the recording frequency continuously from the inner circumference to the outer circumference or from the outer circumference to the inner circumference in accordance with the recording radius position, with the emission waveform of the laser light as a recording pulse train consisting of a plurality of ON pulses followed by OFF pulses. What is claimed is: 1. A recording method for a recording medium, comprising continuously combining a part for fixing the widths of the plurality of on-pulses with the same time constant and a part for multiplying the window width by a constant. A method is provided.

According to the second aspect of the present invention, information is recorded on the optical information recording medium by changing the length of a recording mark which forms an amorphous portion generated by irradiating the LD in the crystal of the recording layer. The length of the recording mark is controlled by the number of the recording pulse trains (n + 1) (where n is an integer of 1 to 13), and 14 of the two recording pulse trains are used. The n + 1 falling pulse position X in which up to the pulse train is used at random is such that when recording at the same recording linear velocity, it always falls at the same position within the reference clock width on the optical information recording medium. Methods included.

Further, in the second invention, the n = 1-1
Of the three pulse trains, only when n = 1, the other n = 2-
13 and within the reference clock width, other n = 2-
A recording method for an optical information recording medium that falls with a time constant earlier than 13 is included.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION In general, rewritable optical disks compatible with high-density recording use a recording material in the vicinity of a compound composition of Ge ₂ Sb ₂ Te ₅ , and AgInSbT.
Some recording materials mainly use the composition represented by e. However, due to their compatibility with high-density recording and good erasing characteristics at the time of overwriting, CD-RWs that have already been commercialized and are being widely used are being used. Uses the latter material.
The composition of AgInSbTe-based recording materials is disclosed in, for example, JP-A-8-22644 and JP-A-8-263871. And recently,
A DVD-RW medium capable of high-density rewrite recording of 4.7 GB for video applications has also been commercialized.

This rewritable optical disk has the same capacity as DVD-ROMs whose products are already widely available and is capable of recording at a constant speed, and is also used for AgInSbT.
e-based recording materials have compatible properties. However, in the future, development of an optical disc capable of high linear velocity recording is expected for the purpose of performing recording in a short time even in this application.

As a composition capable of recording at a high linear velocity of an AgInSbTe-based recording material, the present applicant has proposed a composition in which the Ag content is reduced (Japanese Patent Application No. 11-15331).
No. 6). Even with this recording material, for example, DVD-R
Although it was possible to record at 1 × to 2.5 × speed of OM,
In particular, at the time of recording at a speed of 2.5 times or more, for example, it is found that the allowable value of the write power for obtaining good recording characteristics between different drives, the overwriting characteristics, or the storage characteristics during overwriting are not sufficient. Was.

As a result of repeated studies for solving these problems, it was confirmed by experiments that the storage reliability was solved by further adding Ge to the recording layer proposed by the present applicant. Japanese Patent Application Laid-Open No. Hei 8-263871 describes that Ge can be added to AgInSbTe to improve the storage reliability. For example, DVD-RO
In a recording linear velocity region corresponding to 2.5 times the speed of M, S
Experiments have also confirmed that the addition amount of b is small, and the addition of Ge also has the disadvantage of lowering the modulation degree of the disk.

This problem can be solved by using Ag or an Ag alloy for the reflective layer.
Alternatively, when an Ag alloy is used for the reflection layer, the conventional ZnS
When -SiO ₂ upper protective layer is in direct contact with Ag or Ag alloy, because the sulfurization of Ag, not good recording characteristics are obtained, in the order to prevent this, between the ZnS-SiO ₂ and the reflective layer, Si It has also been confirmed that carbides or nitrides of these and those or a mixture of these or oxide dielectrics are effective.

[0023] Therefore, in this case, the allowable value of the write power for obtaining good recording characteristics between different drives and the overwrite characteristics are also improved. Also,
When a drive is designed for low power consumption, a CAV method is employed in which recording is performed with the motor rotating at a constant speed.
At the outermost periphery of a disc having the same diameter of 120 mm as the RW,
2.5 times the linear velocity. In order to realize a recording medium corresponding to a linear velocity of 1 to 2.5 times, the above-described medium structure gives a good result. However, by devising a recording strategy, the recording characteristics can be improved. Can be achieved. In particular, in order to make the recording characteristics flat at a linear velocity of 1 to 2.5 times, it is important to adjust the recording strategy.

The present applicant has proposed a strategy effective for recording on a CAV for a SbTe + M recording medium having a four-layer structure using an Al reflective film (Japanese Patent Application No. 11-31926).
), The effectiveness of the recording medium according to the present invention has been confirmed, and further effective improvements have been made.

Therefore, the present invention firstly provides a transparent substrate
A first dielectric layer, a phase change recording layer, a second dielectric layer, and a metal reflective layer are formed by sputtering in that order, and the material of the first and second dielectric layers is a mixture of ZnS and SiO ₂ ; the composition of the material of the phase-change recording layer an optical information recording medium with _{Ag a in b Sb c Te d} , to the composition _{Ag a in b Sb c Te d} , adding an element X _e other than said set forming component And the metal reflection layer is made of Ag or an Ag alloy, and a third dielectric layer made of a material other than sulfide is provided between the second dielectric layer and the metal reflection layer. Optical information recording medium [However, a, b, c, and d have the relationship of the following formulas (1) to (4), and when c / (c + d) is r, the relationship of the following formula (5) Shall be provided). 0 <a ≦ 0.01 (1) 0.03 ≦ b ≦ 0.10 (2) 0.40 ≦ d ≦ 0.70 (3) a + b + c + d = 1 (4) 0.60 ≦ r ≦ 0.85 ( 5)

When the composition of the recording layer material is represented by the above formula (1)
In the relationship between (4) and (5), when (1) exceeds this range, the optical recording medium used for CAV recording, particularly at a high linear velocity recording speed, has a jitter, a reflectance, and a modulation factor. And other basic characteristics. If not added at all, the storage stability deteriorates.
If (2) exceeds this range, the amorphous mark will be crystallized by the reading light of the drive, and there is a high possibility that the shape of the mark of the optical recording medium will be damaged.
If the amount is small, it is difficult to obtain a modulation degree, and as a result, the reproduction jitter is deteriorated. When (3) exceeds this range, as in (1), the optical information recording medium used for CAV recording, particularly at a recording speed on the high linear velocity side, has basic characteristics such as jitter, reflectance, and modulation. If the characteristics are deteriorated, and if the amount is small, a problem that storage stability is deteriorated occurs, which is not preferable.

The element Xe is preferably Ge. [However, the addition amount e is assumed to be in the relationship of the following formula (6)]. 0.005 ≦ e ≦ 0.07 (6) When the addition amount is too large in the above formula (6), basic recording conditions such as jitter, reflectance, and degree of modulation at a high linear velocity side recording speed are obtained. This leads to deterioration of the characteristics, and if the amount is small, there is a problem that storage stability deteriorates.
Not desirable.

The ratio of the thickness of the second dielectric layer to the first dielectric layer (R1 = the thickness of the second dielectric layer / the thickness of the first dielectric layer) satisfies the following equation (7). Is preferred. 0.1 ≦ R1 ≦ 0.5 (7)

Further, in the optical information recording medium of the present invention, it is preferable that the thermal conductivity of the third dielectric layer is higher than the thermal conductivity of the second dielectric layer. The relationship between the thickness and the thermal conductivity of the third dielectric layer is the second dielectric layer.
By being larger than that of the dielectric layer,
This is because heat generated by absorbing the LD light in the recording layer is efficiently radiated to the reflective heat radiation layer, so that a stable amorphous mark can be obtained even at the time of high linear velocity recording.

Further, the thickness ratio of the third dielectric layer to the second dielectric layer (R2 = third dielectric layer thickness / second dielectric layer thickness) is expressed by the following equation (8). Preferably, there is. 0.1 ≦ R2 ≦ 0.5 (8)

Further, the material of the third dielectric layer is a metal carbide or a mixture of a metal oxide and a metal oxide or a metal nitride, and the metal of the metal carbide is Si;
Preferably, the metal of the metal oxide or metal nitride is Si, Ti or Al. The metal of the metal carbide is Si, and the metal of the metal oxide or metal nitride is Si
Or by Al, the relationship of the thermal conductivity,
This is because the film becomes favorable from the viewpoint of the uniformity of the film.

Secondly, in recording optical information on the optical information recording medium, the present invention uses a recording pulse train composed of a plurality of on-pulses followed by off-pulses in the emission waveform of the laser light, and records the recording from the inner periphery to the outer periphery or from the outer periphery. What is claimed is: 1. A recording method for an optical information recording medium in which recording is performed by continuously changing a recording frequency in accordance with a recording radius position on an inner circumference, wherein a portion in which the widths of the plurality of on-pulses are all fixed by the same time constant and a window width And a part for multiplying a constant by a constant is provided.

[0033] In this recording method, as shown in FIG. 2, at the time of recording at the same linear velocity, (n + 1) in each reference clock × T _w, the same position of falling positions in each reference clock of each pulse train By adjusting the pulse width so as to satisfy the above condition, good jitter characteristics can be obtained. Here, n is an integer of 1 to 13. This width is preferably in the range of 0.2 to 0.8 of the width of each reference clock. If it exceeds the range represented by the above formula, the off-pulse portion becomes too short, and sufficient cooling time is reduced, so that a stable amorphous mark cannot be obtained. This is because it is too narrow to obtain a sufficient amount of heat for obtaining an amorphous mark.

Further, in the recording method of the present invention, only the falling position of n = 1 (first pulse) is
The jitter characteristic can be further reduced by using one that falls with a time constant earlier than n = 2-13. At this time, the falling position of n = 1 (first pulse) with respect to the rear end of each pulse train of 2 ≦ n ≦ 13 is set to 2
≦ n ≦ 13 from the rear end position of each pulse train.
The case of 3T is preferable. By fixing the time constant in this way, in an amorphous mark having a length of n = 1 to 13, it is possible to suppress a variation in the overall length of each mark with respect to each reference clock.

Hereinafter, the present invention will be described specifically.
FIG. 1 is a schematic view of an optical recording medium structure of the present invention. The optical information recording medium of the present invention comprises a first dielectric layer 2, a phase-change recording layer 3, a second dielectric layer 4 as an upper protective layer, and a lower protective layer formed on a polycarbonate substrate 1 having a guide groove by sputtering. The third dielectric layer and the metal reflective layer 6 are formed, and the opposite substrate that adheres to the opposite substrate may or may not have each layer functioning as a medium. In the adhesive layer,
An adhesive sheet, a radical ultraviolet curable resin, a cationic polymerization resin, or the like can be used. Further, an environmental protection layer 7 made of an ultraviolet curable resin applied by spin coating may be laminated on the metal reflection layer.

The film forming conditions for each layer are as follows: the first and second dielectric layers have a power supply of 3 kW and an Ar gas pressure (pressure in the film forming chamber).
2 mTorr, and the phase change recording was performed with an input power of 1 kW and A
The r gas pressure (atmosphere of the film forming chamber) was 2 mTorr, the third dielectric layer had a power of 1 kW, and the Ar gas pressure (atmospheric pressure of the film forming chamber).
2 mTorr, the metal reflective layer was 9 kW input power, and A
The r gas pressure (atmospheric pressure in the film forming chamber) was 2 mTorr. First,
The second dielectric layer can be formed by various vapor deposition methods, for example, a vacuum deposition method, a sputtering method, an electron beam deposition method, or the like.

The material of each layer is as follows. The phase change recording layer is formed by adding Ge to conventional AgInSbTe. In order to obtain an optical disk having a higher linear velocity, the Ag content is preferably 1% or less in atomic ratio. Ge is used as an element added for improving storage stability. In addition to Ge, good results can be obtained with AgInSbTe as long as it is an element that lowers the crystallization rate and simultaneously raises the crystallization temperature.
i, N, etc. have similar effects. However,
For a high linear velocity optical disk, this content needs to be suppressed to 7% or less, and particularly, addition of 5% or less is desirable.

The first and second dielectric layers are made of the same Z as in the prior art.
A mixed target of nS (80%) and SiO ₂ (20%) is used. This mixing ratio may be adjusted for the adjustment of the thermal conductivity, but the mixing ratio of SiO ₂ is desirably in a range not exceeding 50%.

For the third dielectric layer, a mixture of SiC and SiO ₂ is used, but it is sufficient that the third dielectric layer has a higher thermal conductivity than the first and second dielectric layers and the main component is a dielectric material other than oxide. . The content of the oxide is preferably at most 20% by weight.

The material used for the metal reflection layer is Ag or Ag.
On the other hand, an element such as Pd, In, Cu, Si, Ge or a mixture thereof, and a metal which becomes eutectic at a content of up to 10% with respect to Ag may be used.
nm is preferred. If it is less than 60 nm, a heat radiation effect cannot be obtained. On the other hand, if the film layer is too thick, it is not preferable because interface peeling tends to occur.

The thickness ratio R1 between the first dielectric layer and the second dielectric layer
= (Second dielectric / first dielectric) preferably satisfies 0.1 ≦ R1 ≦ 0.5. If the first dielectric layer is too thin, the heat absorbed by the recording layer during recording with a laser beam is trapped on the substrate side, and the overwrite characteristics are undesirably deteriorated.

The third dielectric layer preferably has a higher thermal conductivity than the second dielectric layer, and further has a thickness ratio R2
= (Third dielectric / second dielectric) preferably has the following range. 0.1 ≦ R2 ≦ 0.5 When the third dielectric layer is too thick, the heat absorbed by the recording layer during recording with laser light is radiated, and the temperature rise of the recording layer becomes insufficient, and the decrease in recording sensitivity is reduced. It is not preferable because it invites.

As described above, by optimizing the film thickness of the first, second, and third dielectric layers, for example, a DVD-RO
High linear velocity recording of 2.5 times or more of M can be performed, and an optical disk with good overwrite characteristics can be realized.

Recording of information on the optical information recording medium is performed by changing the length of a recording mark (forming an amorphous portion generated by irradiating LD in the crystal of the recording layer). The length of the recording mark is controlled by the number of recording pulse trains (n + 1) described in claim 8, and n is an integer of 1 to 13. As a result, a recording strategy as shown in FIG. 2 is obtained. However, only the first pulse forms a pulse using 2T of the clock, and in the other cases, one pulse rises and rises with respect to the 1T clock. Go down. By using this recording strategy, a recording mark having a length of 3 to 14 times the reference clock width Tw can be formed. A method of performing mark length modulation using a length of 3 to 14 times the clock width Tw is called an EFM + modulation method, and is a known recording modulation method.

Further, the falling pulse position X of each recording pulse train (n + 1, that is, 2 to 14 pulse trains are used at random) according to claim 8
When recording at the same recording linear velocity (same Tw), the mark always falls at the same position within each reference clock width, so that a mark having a length of 3 × T is converted to a length of 14 × T. A recording method in which the length changes relatively linearly up to the mark can be realized. As a result, good jitter characteristics can be recorded. In the present invention, however, only the trailing end of the first pulse is made shorter than the trailing end of the other pulse trains to reduce the length of the 3T-14T mark. The linearity can be further improved.

FIG. 2 is a timing chart showing the pulse arrangement of the recording strategy. The strategy specified in the present invention is disclosed in Japanese Patent Application No. 11-1 proposed by the present applicant.
Although the strategy is basically the same as that shown in JP-A-31926, the recording characteristics of the recording medium of the present invention are also improved by using this strategy.
It was found that a flat jitter characteristic was obtained at a linear velocity of 1.0 to X2.5.

Further, as a result of experimenting on the optimal conditions of the strategy, it was found that it is effective to move only the first pulse of the pulse train forward in time series with respect to the other subsequent pulses. This is shown in FIG.

Table 1 shows the number of repetitive recordings at a recording linear velocity of 8.5 m / s of the optical recording medium of the present invention, together with comparative examples. The number of repetitive recordings is determined by the maximum number of times that the value of the jitter σ / Tw normalized by the window width Tw satisfies the standard value. The track pitch is 0.74 μm.

[0049]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Example 1 A recording layer having the composition shown in Table 1 was
70 nm of the first dielectric layer using the mixed target of ₂ ,
Optical information recording formed by a sputtering method on a polycarbonate substrate, with the second dielectric layer being 15 nm, the third dielectric layer using a mixed target of SiCSiO ₂ being 5 nm, and the metal reflecting layer being using an Ag-Pd alloy target being 140 nm. Recording was performed on the medium using the recording strategy described in claims 8 and 9, and its recording characteristics and storage stability were evaluated. Storage stability is as follows: jitter characteristic is 85 ° C, 85% R
It was judged by the storage time exceeding the reference value under the condition of H.

Example 2 The procedure of Example 2 was repeated except that the composition of the recording layer was changed.

Example 3 Recording was performed on the composition of the recording layer of Example 1 using the recording strategy described in claim 10.

Example 4 Recording was performed on the same recording layer composition as in Example 2 by using the recording strategy described in claim 10. Table 1 shows the conditions and results in Examples 1 to 4.

Example 5 FIG. 3 shows the results of CAV recording using the recording strategy of the eighth and ninth aspects and the recording strategy of the tenth aspect with respect to the recording layer composition of the first example. As a comparative example, a result of performing CAV recording using a strategy in which, of the portion where the same time constant is fixed and the portion where the window width Tw is multiplied by a constant, the portion where the same time constant is fixed is eliminated is described. Shown at the same time. A relatively flat jitter characteristic from the inner circumference to the outer circumference can be obtained by using the recording strategy described in claims 8 and 9, and the jitter characteristic can be improved by using the recording strategy described in claim 10. I understand. It was found that when CAV recording was performed using a strategy in which a portion fixed at the same time constant was eliminated, the jitter rise on the low linear velocity side became remarkable.
This is considered to be because in the strategy in which the part fixed with the same time constant is eliminated, the pulse on the low linear velocity side becomes too narrow.

Comparative Example 1 The recording characteristics and storage stability of the recording layer composition of Example 1 were evaluated using AgInSbTe alone.

Comparative Example 2 In the layer structure of the recording medium of Example 1, the material of the reflective layer was Ag.
Recording characteristics and storage stability were evaluated in the same manner as in Example 1 except that the alloy was changed to an Al-Ti alloy.

Comparative Example 3 Recording was performed using the recording layer composition of Example 1 using a strategy having a recording pulse train one less than the recording strategy described in claims 8 and 9. The length of the entire pulse train was adjusted so as to be the same as the recording strategy described in claims 8 and 9. At the linear recording speed corresponding to the DVD-ROM 1 × speed, the recording characteristics are almost the same as those of the recording strategy according to claims 8 and 9, but the recording characteristics at the recording linear speed corresponding to the 2.5 × speed are poor. Was. Table 1 shows the conditions and results in Comparative Examples 1 to 3.

[0058]

[Table 1]

[0059]

According to the present invention, there is provided a rewritable optical information recording medium having the same capacity as a DVD-ROM, having good recording characteristics at high linear velocity recording, especially good characteristics relating to modulation. Further, an optical information recording medium having improved storage stability, particularly, an overwrite archival life, and a recording method for this medium are provided, which greatly contributes to the optical information recording field.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical information recording medium of the present invention.

FIG. 2 is a timing chart showing a pulse arrangement of a recording strategy.

FIG. 3 is a diagram showing a state of a recording strategy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 1st dielectric layer 3 Recording layer 4 2nd dielectric layer 5 3rd dielectric layer 6 Metal reflection layer 7 Environmental protection layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G11B 7/24 538 G11B 7/24 538E B41M 5/26 7/0045 A G11B 7/0045 B41M 5/26 X (72) Inventor Takashi Shibaguchi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Hajime Hajime 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Eiko Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Nobuaki Onagi 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Hiroko Tashiro, Inventor 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 2H111 EA04 EA12 EA23 FA01 FA12 FA21 FA23 FA25 FA27 FA28 FB05 FB09 FB12 FB17 FB2 1 FB30 GA03 5D029 JA01 LA17 LB01 LB07 LB11 LC17 MA13 5D090 AA01 BB05 BB17 CC01 CC12 DD03 EE02 FF21 KK04 KK05

Claims (10)

[Claims] 1. A first dielectric layer, a phase-change recording layer, a second dielectric layer, and a metal reflective layer are formed on a transparent substrate by sputtering in this order, and materials of the first and second dielectric layers are formed. the an optical information recording medium mixture and then, the composition of the material of the phase change recording layer was Ag _a in _b Sb _c Te _d of ZnS and SiO _2,
The composition Ag _a In _b Sb _c Te _d respect, the addition of element X _e other than said set forming component, the metal reflective layer Ag or A
g information alloy, wherein a third dielectric layer made of a material other than sulfide is provided between the second dielectric layer and the metal reflection layer, wherein a, b , C, d
Is in the relationship of the following formulas (1) to (4), and c / (c
When + d) is r, the following equation (5) is assumed. 0 <a ≦ 0.01 (1) 0.03 ≦ b ≦ 0.10 (2) 0.40 ≦ d ≦ 0.70 (3) a + b + c + d = 1 (4) 0.60 ≦ r ≦ 0.85 ( 5) 2. The optical information recording medium according to claim 1, wherein said element Xe is Ge [where the addition amount e is represented by the following formula (6):
It is assumed that there is a relationship]. 0.005 ≦ e ≦ 0.07 (6) 3. The thickness ratio of the second dielectric layer to the first dielectric layer (R1 = second dielectric layer thickness / first dielectric layer thickness).
3. The optical information recording medium according to claim 1, wherein the optical information recording medium has a relationship represented by the following expression (7). 0.1 ≦ R1 ≦ 0.5 (7) 4. The thermal conductivity of the third dielectric layer is higher than the thermal conductivity of the second dielectric layer.
The optical information recording medium according to any one of the above. 5. The thickness ratio of the third dielectric layer to the second dielectric layer (R2 = third dielectric layer thickness / second dielectric layer thickness).
The optical information recording medium according to any one of claims 1 to 4, wherein the optical information recording medium has a relationship represented by the following formula (8). 0.1 ≦ R2 ≦ 0.5 (8) 6. The optical information recording medium according to claim 1, wherein the material of the third dielectric layer is a metal carbide or a mixture of a metal carbide and a metal oxide or a metal nitride. 7. The metal of the metal carbide is Si, and the metal of the metal oxide or metal nitride is Si, Ti or A.
The optical information recording medium according to claim 6, which is 1. 8. When recording optical information on the optical information recording medium according to any one of claims 1 to 7, the emission waveform of the laser light is a recording pulse train composed of a plurality of on-pulses followed by off-pulses. A recording method for an optical information recording medium in which recording is performed by continuously changing a recording frequency in accordance with a recording radius position from an outer circumference or an outer circumference to an inner circumference, wherein the widths of the plurality of on-pulses are all fixed at the same time constant. A recording method for an optical information recording medium, characterized by continuously combining a portion to be performed and a portion for multiplying a window width by a constant. 9. Recording of information on an optical information recording medium is performed by changing the length of a recording mark that forms an amorphous portion generated by irradiating an LD in a crystal of a recording layer. The length is controlled by the number of the recording pulse train (n + 1) (however,
n is an integer of 1 to 13), and n + 1 falling pulse positions X, in which each of the recording pulse trains from 2 pulse trains to 14 pulse trains are randomly used, are recorded at the same recording linear velocity. 9. The recording method for an optical information recording medium according to claim 8, wherein the data always falls at the same position in each reference clock width. 10. In the pulse train of n = 1-13, n =
Only when it is 1, the other n in the reference clock width
10. The recording method for an optical information recording medium according to claim 8 or 9, wherein the optical information recording medium falls with a time constant earlier than 2-13.