JP2003331460A - Optical information recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phase transition type optical information recording medium having the high stability with respect to a reproduced light while allowing the high linear speed recording. <P>SOLUTION: In the optical information recording medium, whereon at least a phase transition type recording layer is provided on a transparent substrate having a concentric or spiral guide groove and the phase transition is generated in the recording layer by emitting semiconductor laser beams to record or rewrite the information and also the reproduction of the recorded information is performed by utilizing a reflected light at the emission of the semiconductor laser beams, the activated energy Ea of the signal deterioration at the reproduction is arranged to be 0.8-1.5 eV, or the activated energy Ea of the signal deterioration when the reproduced light having the wavelength λ of 640-670 nm of semiconductor laser beams, the number of openings NA of 0.64-0.66 of an optical lens and the laser power Pr of 0.6-0.8 mW is emitted at the reproducing linear speed of 3.5 m/s, is arranged to be 0.8-1.5 eV. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase change type optical information recording medium which records, reproduces and rewrites information by causing a phase change in a recording layer material by irradiating a laser beam.

[0002]

2. Description of the Related Art Recording is possible only once as an optical information recording medium for recording / reproducing by irradiation of laser light (write-once type).
CD-R, DVD-R, rewritable MD, MO
Disc, CD-RW, DVD-RAM, DVD-R
Various media such as W and DVD + RW have been put to practical use, and as removable media, demand is increasing year by year in place of magnetic recording media such as cassette tapes and floppy (registered trademark) disks. Among these optical information recording media, CD-RW, DVD-RAM, DVD-R
W, DVD + RW, etc. are crystalline-type materials for the recording layer.
A so-called phase change material is used which utilizes a transition between an amorphous phase or a crystal-crystal phase. Generally, when information is recorded on a phase-change optical information recording medium, pulsed light in which the power level of laser light is modulated in three stages is irradiated to irradiate the recording layer with a crystalline phase (1 signal) in a high reflectance state. And a non-crystalline (amorphous) phase with low reflectance (0 signal), recording and rewriting (direct overwrite)
Since recording, erasing, and rewriting can be performed by controlling heating by irradiation of laser light, overwriting with a single beam is easy, unlike magneto-optical memory, and recording / reproducing is performed. The optical system on the device side can be further simplified. Therefore, in the field of rewritable optical information recording media, demand for phase change optical information recording media is increasing.

However, in the phase change type optical information recording medium, since the state change of the recording material is controlled by heating by irradiation with laser light, the recording mark ( The quality of the reproduction signal may deteriorate due to crystallization of the amorphous phase). This quality deterioration is more strongly influenced as the heat storage amount increases. Therefore, as the wavelength of the reproduction laser light is shorter, the spot diameter is smaller, the power is larger, and the reproduction linear velocity is faster (the irradiation interval of light is shorter), the degree of deterioration becomes larger. Further, in a phase change type information recording medium compatible with high linear velocity recording, a phase change material that is more easily crystallized is often used in order to secure the characteristics, and the degree of deterioration with a reproduction laser beam becomes large. There is. Therefore, the wavelength of the recording / reproducing laser beam is λ780n.
m, a CD recording / reproducing apparatus having an optical lens numerical aperture NA of 0.5, records at 1 to 4 times speed (recording linear velocity: 1.2 to
4.8 m / s) When recording on a compatible CD-RW disc and reproducing it, the stability to the reproducing light, which had no problems, is the wavelength of the recording / reproducing laser light λ655.
nm and an optical lens numerical aperture NA of 0.65, a DVD recording / reproducing apparatus for 1 to 2.4 times speed recording (recording linear velocity: 3.49 to 8.44 m / s) records a DVD + RW disc. When playing, it could be a problem.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a phase change type optical information recording medium capable of high linear velocity recording and having high stability against reproducing light.

[0005]

[Means for Solving the Problems] The above problems are solved in the following 1) to
It is solved by the invention of 4) (hereinafter, referred to as the inventions 1 to 4). 1) At least a phase-change recording layer is provided on a transparent substrate having concentric or spiral guide grooves, and a semiconductor laser beam is irradiated to cause a phase change in the recording layer to record and rewrite information. In addition, in the optical information recording medium in which the reflected light when the semiconductor laser light is irradiated is used for reproducing the recorded information, the activation energy Ea for signal deterioration at the time of reproduction is 0.8 to 1. 5 eV
An optical information recording medium characterized by: 2) At least a phase-change recording layer is provided on a transparent substrate having concentric or spiral guide grooves, and a semiconductor laser beam is irradiated to cause a phase change in the recording layer to record and rewrite information. In the optical information recording medium in which the reflected light when the semiconductor laser light is irradiated is used for reproducing the recorded information, the wavelength of the semiconductor laser light is λ640 to 670 nm, and the numerical aperture NA of the optical lens is
0.64 to 0.66, laser power Pr 0.6 to 0.
The activation energy Ea of signal deterioration when the reproduction light of 8 mW is irradiated at the reproduction linear velocity of 3.5 m / s is
An optical information recording medium having a voltage of 0.8 to 1.5 eV. 3) When recording information with mark edge recording,
Recording when recording or rewriting a 0 signal whose signal width is nT (T is a clock time) is continuous light of power level Pe, and recording when rewriting or rewriting a 1 signal whose signal width is nT. The pulse includes a pulse portion fp having a power width Pw with a time width xT and a total of (n-
The time width (1−y) T between the high level pulse of the power level Pw ′ and the high level pulse with the time width yT of n ′) times.
And a pulse part ep having a power level Pb of a low level pulse and a power level Pb ′ having a time width zT, where 0 ≦ x, y, z ≦.
1, n and n ′ are positive integers satisfying n ′ ≦ n, recording is performed as a pulse pattern of recording light having power levels (Pw and Pw ′)>Pe> (Pb and Pb ′), and the recorded information is recorded. When erasing is performed, a recording method for an optical information recording medium that irradiates continuous light of power level Pe is used in the same manner as the recording of the 0 signal, and the wavelength of the semiconductor laser light λ640 to 640
670 nm, numerical aperture NA of optical lens 0.64 to 0.6
6, or 0.59 to 0.61, laser power Pr
Characteristic values when reproduced at 0.6 to 0.8 mW and a reproduction linear velocity of 3.5 m / s are jitter (σ / T) of 8.0% or less, reflectance of 18% or more, and modulation degree of 0.60 or more. The optical information recording medium according to 1) or 2), wherein the recording signal can be recorded at a recording linear velocity of 3.0 to 8.5 m / s. 4) When recording information with mark edge recording,
Recording when rewriting or rewriting a 0 signal having a signal width of nT (T is a clock time) is continuous light of a power level Pe, and recording when rewriting or rewriting of a 1 signal having a signal width of nT. The pulse includes a pulse portion fp having a power width Pw with a time width xT and a total of (n-
The time width (1−y) T between the high level pulse of the power level Pw ′ and the high level pulse with the time width yT of n ′) times.
And a pulse part ep having a power level Pb with a low level pulse and a power level Pb ′ with a time width zT, where 0 ≦ x, y, z ≦.
1, n and n ′ are positive integers satisfying n ′ ≦ n, recording is performed as a pulse pattern of recording light having a power level of (Pw and Pw ′)>Pe> (Pb and Pb ′), and the recorded information is recorded. When erasing data, the method of recording on the optical information recording medium which irradiates continuous light of power level Pe is used similarly to the recording of 0 signal, and the wavelength of the semiconductor laser light λ640 to 640
670 nm, numerical aperture NA of optical lens 0.64 to 0.6
6, or 0.59 to 0.61, laser power Pr
Characteristic values when reproduced at 0.6 to 0.8 mW and a reproducing linear velocity of 3.5 m / s are jitter (σ / T) of 8.0% or less, reflectance of 18% or more, and modulation degree of 0.60 or more. The optical information recording medium as described in 1) or 2) above, wherein the recording signal can be recorded at a recording linear velocity of 10.0 to 14.0 m / s.

The present invention will be described in detail below. An example of the layer structure of the optical information recording medium of the present invention is shown in FIG. The basic structure is that a lower protective layer 2, a recording layer 3, an upper protective layer 4, a reflective layer 5, and an overcoat layer 6 are provided on a transparent substrate 1 having a guide groove. Further, a printed layer 8 is formed on the overcoat layer, and a hard coat layer 7 is formed on the mirror side of the substrate.
May be provided. Furthermore, the above-mentioned single plate disks may be bonded together via the adhesive layer 9. The disk on the opposite surface to be bonded may be a transparent substrate alone, in addition to the same single plate disk. Alternatively, the single-layer disc may be laminated without forming the printing layer, and after the lamination, the printing layer 8'may be formed on the opposite surface side.

The material of the substrate may be transparent and has a certain degree of rigidity, and is usually glass, ceramics or resin, and a resin substrate is preferable in terms of moldability and cost. Examples of the resin include polycarbonate resin, acrylic resin, epoxy resin, polystyrene resin, acrylonitrile-styrene copolymer resin, polyethylene resin, polypropylene resin, silicone resin, fluorine resin, ABS resin, urethane resin and the like. Polycarbonate resin and acrylic resin, which are excellent in moldability, optical characteristics and cost, are preferable. In addition, a guide groove is usually formed on the substrate.

As a material for the recording layer, a phase-change recording material containing Sb and Te, which is capable of undergoing a phase change between a crystal phase and an amorphous phase and being in a stabilized or meta-stabilized state, is recorded (amorphous). It is suitable because it has good sensitivity and speed, erase (crystallization) sensitivity and speed, and erase ratio. In this SbTe material, Ga, Ge, Ag, In,
By adding elements such as Bi, C, N, O, Si and S, it is possible to improve recording / erasing sensitivity, signal characteristics, reliability and the like. Therefore, by adjusting the composition ratio of the element or material to be added to control the optimum recording linear velocity according to the target recording linear velocity and linear velocity region, at the same time as the reproduction stability of the recorded signal and the signal life (reliability It is desirable to secure

In the phase-change type optical information recording medium used in the present invention, Ag and / or Ge, Ga as constituent elements are used as a material of the recording layer which can satisfy these characteristics comprehensively.
And / or In, Sb, Te, and the composition formula of these elements is (Ag and / or Ge) _α (Ga and / or In) _β Sb _γ Te _δ (α, β, γ, δ are atoms. %, Α
+ Β + γ + δ = 100), a material satisfying the following conditions can record from a low linear velocity region to a high linear velocity region, and has excellent reproduction stability of the recorded signal and excellent signal life. Therefore, it is preferable. 0 <α ≦ 6 2 ≦ β ≦ 10 60 ≦ γ ≦ 85 15 ≦ δ ≦ 27

The thickness of the phase change recording layer as described above is 1
The thickness is 0 to 50 nm, preferably 12 to 30 nm. Considering initial characteristics such as jitter, overwrite characteristics, and mass production efficiency, the thickness is more preferably 14 to 25 nm. When the thickness is less than 10 nm, the light absorption ability is remarkably lowered, and it cannot serve as a recording layer. If it is thicker than 50 nm, it is difficult for a uniform phase change to occur at high speed. Such a phase change recording layer can be formed by various vapor phase growth methods such as vacuum vapor deposition, sputtering, plasma CVD, photo CVD, ion plating and electron beam vapor deposition. Among them, the sputtering method is excellent in terms of mass productivity and film quality.

Protective layers are formed below and above the phase-change recording layer. The material of the protective layer is Si
O, SiO ₂ , ZnO, SnO ₂ , Al ₂ O ₃ , TiO
₂ , metal oxides such as In ₂ O ₃ , MgO, and ZrO ₂ ; S
nitrides such as i ₃ N ₄ , AlN, TiN, BN, ZrN;
ZnS, In ₂ S ₃ , TaS _{4 and} other sulfides; SiC, T
Carbides such as aC, BC, WC, TiC, and ZrC; diamond-like carbon or a mixture thereof. These materials may be used alone as the protective layer, but they may be mixed with each other and may contain additives as required. Further, the structure may be one in which two or more layers are stacked instead of a single layer. However, the melting point of the protective layer needs to be higher than that of the phase change recording layer. Such a protective layer can be formed by various vapor phase growth methods such as vacuum deposition method, sputtering method, plasma CVD method, photo CVD method, ion plating method, and electron beam evaporation method. Among them, the sputtering method is excellent in terms of mass productivity and film quality.

The thickness of the lower protective layer has a great influence on the reflectance, the degree of modulation, and the recording sensitivity. Therefore, in order to obtain good signal characteristics, the thickness is preferably 60 to 120 nm. The thickness of the upper protective layer is 5 to 45 nm, preferably 7 to 40 nm
And When the thickness is less than 5 nm, the function as the heat resistant protective layer is not fulfilled and the recording sensitivity is lowered. On the other hand, when the thickness is more than 45 nm, interfacial peeling is likely to occur and the repetitive recording performance is also deteriorated.

As the reflective layer, Al, Au, Ag, C
A metal material such as u, Ta, Ti, W, or an alloy containing these elements can be used. Further, in order to improve corrosion resistance, thermal conductivity, etc., the above materials should be made of Cr, T
Elements such as i, Si, Cu, Ag, Pd and Ta may be added. The addition ratio is suitably 0.3 to 2 atomic%. If it is less than 0.3 atomic%, the effect of corrosion resistance is poor. If it exceeds 2 atomic%, the thermal conductivity will increase too much,
It becomes difficult to form an amorphous state. Such a reflective layer can be formed by various vapor deposition methods such as a vacuum vapor deposition method, a sputtering method, a plasma CVD method, a photo CVD method, an ion plating method and an electron beam vapor deposition method. The thickness of the reflective layer is 50 to 200 nm, preferably 70 to
It is 160 nm. It is also possible to make the reflective layer multi-layered. In the case of multilayering, the thickness of each layer must be at least 10 nm, and the total thickness of the multilayered film is 50 to 1
The thickness is preferably 60 nm.

An overcoat layer is formed on the reflective layer to prevent its oxidation. As the overcoat layer, an ultraviolet curable resin produced by a spin coating method is generally used. The appropriate thickness is 3 to 15 μm. Three
When the thickness is less than μm, an increase in error may be observed when the printing layer is provided on the overcoat layer. On the other hand, if it is thicker than 15 μm, the internal stress becomes large and the mechanical properties of the disk are greatly affected.

As the hard coat layer, an ultraviolet curable resin produced by a spin coat method is generally used. The appropriate thickness is 2 to 6 μm. If it is thinner than 2 μm,
Sufficient scratch resistance cannot be obtained. If it is thicker than 6 μm,
The internal stress becomes large, which greatly affects the mechanical properties of the disk. Its hardness must be equal to or higher than the pencil hardness H, which does not cause a large scratch even if it is rubbed with a cloth. If necessary, mix conductive materials to prevent static electricity,
It is also effective to prevent adhesion of dust and the like.

The printing layer is for the purpose of ensuring scratch resistance, label printing of brand names and the like, formation of an ink receiving layer for an ink jet printer, etc., and generally an ultraviolet curable resin is formed by a screen printing method. Is. A suitable thickness is 3 to 50 μm. If the thickness is less than 3 μm, unevenness occurs during layer formation. If it is thicker than 50 μm, the internal stress becomes large and the mechanical properties of the disk are greatly affected.

As the adhesive layer, an adhesive such as an ultraviolet curable resin, a hot melt adhesive or a silicone resin can be used. The material of such an adhesive layer is applied on the overcoat layer or the printing layer by a method such as spin coating, roll coating, or screen printing according to the material,
Ultraviolet irradiation, heating, pressurization, etc. are performed and the disc on the opposite side is attached. The disk on the opposite surface may be the same single plate disk or only a transparent substrate, and the bonding surface of the disk on the opposite surface may or may not be coated with the material of the adhesive layer. A pressure-sensitive adhesive sheet can also be used as the adhesive layer. The thickness of the adhesive layer is not particularly limited, but is preferably 5 to 100 μm in consideration of the coating properties of the material, the curability, and the influence on the mechanical properties of the disk. The range of the adhesive surface is not particularly limited, but D
When applied to an optical information recording medium capable of VD and / or CD compatibility, it is desirable that the position of the inner peripheral edge is within φ15-40 mm, preferably within φ15-30 mm in order to secure the adhesive strength. .

In the optical information recording medium of the present invention, the activation energy for signal deterioration at the time of reproduction by the optical information recording device is determined by the material and film thickness of the recording layer, the upper and lower protective layers, the reflective layer, and the substrate. The activation energy can be controlled by adjusting the heat resistance of the recording material and the heat dissipation of the recording medium by adjusting the shape of the guide groove. For example, the amount of Ge contained in the material of the recording layer may be increased, the amount of In contained may be reduced, the film thickness of the upper protective layer may be reduced, Ag having high thermal conductivity may be used as the reflective layer material, The activation energy can be reduced by narrowing the width of the guide groove of the substrate.

As an example of the method for recording information on the optical information recording medium of the present invention, as shown in FIG. 2, the phase change type optical information recording medium is rotatably driven by a driving means composed of a spindle motor to record / reproduce. Drive the light source consisting of a semiconductor laser by the laser drive circuit of the pickup for
The optical information recording medium is irradiated with laser light through an optical system. At this time, when recording one signal, laser light having a pulse strategy having the fp portion, the mp portion, and the ep portion as shown in FIG. 3 is irradiated. This light irradiation causes a phase change in the recording layer of the optical information recording medium, and the reflected light from the optical information recording medium is received by the recording pickup to record information on the optical information recording medium. As the recording means, a so-called mark edge recording (PWM recording) system is used in which the marks are recorded on the recording layer of the optical information recording medium so that the width of the marks corresponds to the signal. Normally, a signal to be recorded is used in a modulator for a clock, and an EFM (Ei) suitable for recording information on a rewritable compact disc is used.
ght-to-Fourteen Modulatio
n) Recording is performed by modulating with a modulation method or an improved modulation method thereof.

When recording is performed by the PWM recording method, the signal width after modulation is nT (n is a predetermined positive integer value, T is clock time: time corresponding to the cycle of the clock used for signal modulation). The recording pulse for recording (rewriting) the 0 signal is continuous light of power level Pe. On the other hand, as for the recording pulse when recording one signal having a signal width after modulation of nT, as shown in FIG. 3, a pulse of a recording pulse pattern having an fp portion, an mp portion, and an ep portion described below. Let it be light. That is, the time width x
The pulse part fp having the power level Pw at T and the total (n-
A high level pulse of power level Pw ′ with a time width yT of n ′) times and a time width (1-y) between the high level pulses.
It is assumed that the recording light has a pulse pattern composed of a multi-pulse part mp having a low level pulse having a power level Pb at T and a pulse part ep having a power level Pb ′ at a time width zT. Here, 0 ≦ x, y, z ≦ 1, n and n ′ are positive integers of n ′ ≦ n, and the power level is (Pw and P
w ′)>Pe> (Pb and Pb ′). FIG. 3 shows n
= 4, n '= 2.

As an optical system used for recording / reproducing, for example, in a CD-compatible optical information recording apparatus using an infrared semiconductor laser, the wavelength λ770 of laser light is used.
-800 nm, numerical aperture NA of optical lens 0.49-0.
51 or 0.44 to 0.46 is commonly used,
In a DVD-compatible optical information recording device using a red semiconductor laser, the wavelength of laser light is λ640 to 670 nm,
The numerical aperture NA of the optical lens is 0.64 to 0.66, or
0.59 to 0.61 is generally used, and an optical information recording device using a blue semiconductor laser (for example, Blue-r
ay Disc compatible device), laser light wavelength λ395 to 415 nm, optical lens numerical aperture NA 0.8
3 to 0.86 or 0.64 to 0.66 is generally used.

Recording is performed on the optical information recording medium of the present invention by using the above-described recording method, and jitter (clock to data jitter, σ /
T), the reflectance, and the degree of modulation are respectively 8.0% or less, 1
When recording is repeated 8% or more and 0.60 or more, the activation energy Ea when the number of times of reproduction in which the jitter exceeds 9.0% is the life is 0.
8 to 1.5 eV is desirable, and more preferably,
It is desirable that it is 1.1 to 1.4 eV. When the activation energy Ea is less than 0.8 eV, the signal stability is low, the reproduction signal is deteriorated relatively easily, and the durability of repeated reproduction is low. When Ea is larger than 1.5 eV, the fluctuation with respect to the change of the environmental temperature is large, and even a recording medium which has a sufficient durability against repeated reproduction at a general room temperature (25 ° C.) is deteriorated at a high temperature. Is accelerated, and when used in a heated environment or at a high room temperature, the durability against repeated reproduction becomes low. Activation energy Ea is 0.8 eV
FIG. 4 shows an example of the temperature dependence of the number of times of regeneration at 1.5 and 1.5 eV (1.0E on the vertical axis in the figure).
+05 to 1.0E + 10 is 1.0 × 10 ^{5 to} 1.0 ×
10 means 10 ¹⁰ ).

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 A polycarbonate substrate was prepared by injection molding and
Lower protective layer, recording layer, upper protective layer and reflective layer on the plate
The layers were sequentially stacked by the sputtering method. Lower and upper guard
ZnS / SiO for the protective layer_Two, Recording layer is Ag_TwoGe_TwoIn
_FourSb ₆₈Te₂₄Ag for the phase change recording material and reflective layer
The film thickness is 80 nm, 20 nm, 2 from the substrate side in this order.
It was set to 0 nm and 150 nm. In addition, UV-hardening on the reflective layer
Forming an overcoat layer by spin coating of chemical resin
And phase-change optical information compatible with DVD-ROM reproduction
A single disk as a recording medium was created. Then overcoat
Bond the polycarbonate substrate onto the contact layer via the adhesive layer.
The surface of the polycarbonate substrate (
Form a printing layer on the (facing) side to obtain a bonded disc
It was After that, a large-diameter LD (beam diameter 200 × 1 μm)
Of the phase change type optical information recording medium
The entire surface of the recording layer was crystallized. D obtained in this way
For an optical information recording medium having VD-ROM compatibility,
Laser wavelength λ660nm, optical lens NA 0.65
For optical information recording / reproducing device for DVD using optical system
Recording linear velocity 8.5m / s, recording power 13.5m
When recorded at W, jitter is 7.0%, reflection
The signal of the characteristic value of the rate is 20.2% and the degree of modulation is 0.64.
I was able to record. For this recorded area, set the ambient temperature
For each at 25 ℃, 35 ℃, 45 ℃
Then, by the above reproducing apparatus, the reproducing laser power Pr
Repeated reproduction was performed at 0.8 mW. Repeatedly
The correlation graph between the live frequency and the jitter is shown in FIG. 5, and the jitter is 9.0.
Table 1 shows the number of playbacks exceeding%, and the reflectance and modulation at that time.
Shown in. In addition, the number of playback times when the jitter exceeds 9.0%
Fig. 6 shows an Arrhenius plot graph for life.
You In addition, E + 00 to E + 1 in FIGS.
0 is × 10⁰-10¹⁰Means from this result,
The activation energy Ea was 1.20 eV. Obey
Then, the environmental temperature 55 required from this activation energy
The life of the number of times of regeneration at ℃ is> 1 x 10 from Fig. 6.⁶Times
It was a good result.

Example 2 A polycarbonate substrate was produced by injection molding, and a lower protective layer, a recording layer, an upper protective layer and a reflective layer were sequentially laminated on this substrate by a sputtering method. ZnS.SiO ₂ is used for the lower and upper protective layers, and Ge ₅ Ga ₄ Sb is used for the recording layer.
₆₉ Te ₂₂ phase change recording material, Ag used for the reflective layer,
The film thickness is 70 nm, 15 nm, 15 n in order from the substrate side.
m and 130 nm. Furthermore, an overcoat layer is formed on the reflective layer by spin coating an ultraviolet curable resin,
A single plate disk of a phase change type optical information recording medium having DVD-ROM reproduction compatibility was prepared. Next, a polycarbonate substrate was bonded onto the overcoat layer via an adhesive layer, and a printing layer was formed on the surface of the polycarbonate substrate (opposite to the bonding surface) to obtain a bonded disk.
After that, the entire surface of the recording layer of the phase-change optical information recording medium was crystallized by an initialization device having a large diameter LD (beam diameter 200 × 1 μm). DVD obtained in this way
-Recording linear velocity of 14.0 m / s with a DVD compatible optical information recording / reproducing apparatus using an optical system of laser wavelength λ660 nm and optical lens NA 0.65 for an optical information recording medium having ROM compatibility. Power 20.0m
When recording was performed at W, a signal having characteristic values of jitter of 7.8%, reflectance of 19.1% and modulation of 0.62 could be recorded. With respect to each of the recorded portions, the reproduction laser power Pr was set by the above-mentioned reproducing device when the ambient temperature was set to 25 ° C, 35 ° C, and 45 ° C.
Repeated reproduction was performed at 0.8 mW. Table 1 shows the number of times of reproduction in which the jitter exceeds 9.0%, the reflectance and the modulation degree at that time, and the activation energy Ea calculated therefrom. Since the activation energy Ea obtained here is 1.11 eV, a graph similar to that of FIG. 6 of Example 1 was created, and the life of the number of times of regeneration at an environmental temperature of 55 ° C. was> 1 × 10 ⁶ times. Yes, it was a good result.

[0026]

[Table 1]

[0027]

INDUSTRIAL APPLICABILITY According to the present inventions 1 and 2, it is possible to provide an optical information recording medium which is not easily deteriorated by reproduction and has excellent reproduction stability. According to the present inventions 3 to 4, it is possible to provide an optical information recording medium which is excellent in recording with better signal characteristics and reproduction stability of the recorded signal.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a layer structure of an optical information recording medium of the present invention.

FIG. 2 is a diagram showing an example of a method for recording information on the optical information recording medium of the present invention.

FIG. 3 is a diagram illustrating an example of a pulse strategy of irradiation laser light.

FIG. 4 shows activation energy Ea of 0.8 eV and 1.e.
The figure which shows an example about the temperature dependence of the number of times of reproduction | regeneration in the case of 5 eV.

FIG. 5 is a diagram showing a correlation graph of the number of repeated reproductions and jitter when the environmental temperature is 25 ° C., 35 ° C., and 45 ° C.

FIG. 6 is a graph showing an Arrhenius plot with the number of times of reproduction in which the jitter exceeds 9.0% as the life.

[Explanation of symbols]

1 transparent substrate 2 lower protective layer 3 recording layer 4 upper protective layer 5 reflective layer 6 overcoat layer 7 hard coat layer 8 printed layer 8'printed layer 9 adhesive layer T clock time Pe power level Pw power level fp pulse of power level Pw Part x time width of pulse part fp [x (T)] Pw 'power level Pb power level mp power level Pw' or pulse part of Pb y time width of power level Pw 'in the pulse part mp [y
(T)] 1-y Time width of power level Pb in pulse part mp [(1-y) T] Pb 'Power level ep Pulse part z of power level Pb' Time width of pulse part ep [z (T) ]

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaki Kato             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F term (reference) 5D029 JB18 JB46 JB47 JC02 JC09                 5D090 AA01 BB05 CC02 CC04 CC14                       DD01 FF09 KK02 KK04 KK05                       KK06 LL01                 5D119 AA31 BA01 BB04 DA02 DA05                       HA27 HA47 HA54 HA60                 5D789 AA31 BA01 BB04 DA02 DA05                       HA27 HA47 HA54 HA60

Claims (4)

[Claims] 1. A transparent substrate having concentric or spiral guide grooves, and at least a phase-change recording layer, which is irradiated with a semiconductor laser beam to cause a phase change in the recording layer to record information. In the optical information recording medium in which rewriting is performed and the recorded information is reproduced by using the reflected light when the semiconductor laser light is irradiated, the activation energy Ea of signal deterioration at the time of reproduction is 0.8. ~
An optical information recording medium having a voltage of 1.5 eV. 2. A transparent substrate having concentric or spiral guide grooves, and at least a phase-change recording layer, which is irradiated with a semiconductor laser beam to cause a phase-change in the recording layer to record information. In an optical information recording medium in which rewriting is performed and recorded information is reproduced by using reflected light when the semiconductor laser light is irradiated, the wavelength of the semiconductor laser light is λ640 to 670 nm, the numerical aperture NA0 of the optical lens is .64 to 0.66, laser power Pr0.
Activation energy E of signal deterioration when reproducing light of 6 to 0.8 mW is irradiated at a reproducing linear velocity of 3.5 m / s.
The optical information recording medium is characterized in that a is 0.8 to 1.5 eV. 3. When recording or rewriting a 0 signal having a signal width of nT (T is a clock time) when recording information by mark edge recording, the recording pulse is continuous light of power level Pe. , A recording pulse for recording or rewriting one signal having a signal width of nT has a pulse portion fp having a power level Pw with a time width xT and a power level with a total of (n−n ′) time widths yT. Between the high level pulse of Pw ′ and the high level pulse, the time width (1-
y) is composed of a multi-pulse part mp having a low level pulse of power level Pb at T, and a pulse part ep having power level Pb ′ at time width zT, where 0 ≦ x, y,
z ≦ 1, n and n ′ are positive integers of n ′ ≦ n and recording is performed by recording as a pulse pattern of recording light having a power level of (Pw and Pw ′)>Pe> (Pb and Pb ′). When erasing the recorded information, the method of recording on the optical information recording medium which irradiates continuous light of power level Pe is used like the recording of the 0 signal, and the wavelength λ64 of the semiconductor laser light is used.
0 to 670 nm, numerical aperture NA of optical lens is 0.64 to
The characteristic value at the time of reproduction at 0.66 or 0.59 to 0.61, laser power Pr of 0.6 to 0.8 mW, and reproduction linear velocity of 3.5 m / s is jitter (σ / T) 8. 2. A recording signal having a reflectance of 0% or less, a reflectance of 18% or more, and a modulation degree of 0.60 or more can be recorded at a recording linear velocity of 3.0 to 8.5 m / s. 2. The optical information recording medium described in 2. 4. A recording pulse used when recording or rewriting a 0 signal having a signal width of nT (T is a clock time) when recording information by mark edge recording is continuous light of power level Pe. , A recording pulse for recording or rewriting one signal having a signal width of nT has a pulse portion fp having a power level Pw with a time width xT and a power level with a total of (n−n ′) time widths yT. Between the high level pulse of Pw ′ and the high level pulse, the time width (1-
y) is composed of a multi-pulse part mp having a low level pulse of power level Pb at T, and a pulse part ep having power level Pb ′ at time width zT, where 0 ≦ x, y,
z ≦ 1, n and n ′ are positive integers of n ′ ≦ n and recording is performed by recording as a pulse pattern of recording light having a power level of (Pw and Pw ′)>Pe> (Pb and Pb ′). When erasing the recorded information, the method of recording on the optical information recording medium which irradiates continuous light of power level Pe is used like the recording of the 0 signal, and the wavelength λ64 of the semiconductor laser light is used.
0 to 670 nm, numerical aperture NA of optical lens is 0.64 to
The characteristic value at the time of reproduction at 0.66 or 0.59 to 0.61, laser power Pr of 0.6 to 0.8 mW, and reproduction linear velocity of 3.5 m / s is jitter (σ / T) 8. 2. A recording signal having a reflectance of 0% or less, a reflectance of 18% or more, and a modulation degree of 0.60 or more can be recorded at a recording linear velocity of 10.0 to 14.0 m / s. 2. The optical information recording medium described in 2.