JP2002329317A - Optical recording medium and optical recording / reproducing method - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To provide a method capable of performing recording efficiently and an optical recording medium used therefor. Kind Code: A1 A recording power P of 15 to an optical recording medium is set.
Test recording and reproduction of information in a pattern consisting of a low reflectivity portion and a high reflectivity portion while sequentially changing in a region including 18 mW, monitoring of a recording signal amplitude m corresponding to a recording power P, and standardization. The gradient g (P) is obtained by the following equation: g (P) = (Δm / m) / (ΔP / P) ΔP: a minute change in the vicinity of P Δm: a minute change in the vicinity of m The optimum recording power is determined by evaluating the excess or deficiency of the recording power based on the slope g (P), and a specific value S selected from the range of 0.2 to 2.0 is set, and the standardization is performed. The recording power Ps at which the slope g (P) coincides with S is detected, and the optimum recording power Po is set by multiplying Ps by a specific value R selected from the range of 1.0 to 1.7. Optical recording / reproducing method characterized by performing

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording and reproducing information on and from an information recording medium such as a compact disc,
The present invention also relates to a rewritable information recording / reproducing method and an optical recording medium.

[0002]

2. Description of the Related Art Conventionally, as described in JP-B-63-29336, an optical recording / reproducing apparatus scans a light spot such as a laser beam while irradiating the light spot on an optical recording medium. There is known a method of recording an information signal on an optical recording medium by intensity-modulating the information signal. Also,
There is also known a method of reproducing a signal recorded on an optical recording medium and optimizing recording conditions such as a recording (light) power and a recording light pulse width by monitoring the amplitude of the reproduced signal and the length of a recording mark. Have been. In the above method, even if an information signal is actually recorded on an optical recording medium using a mass-produced optical recording / reproducing apparatus, it is practically difficult to always set optimal conditions for the following reasons.

That is, in the above method, the amplitude (difference between a signal level from an unrecorded portion and a signal level from a recorded portion) of a recording signal, which is a typical reproduction signal on an optical recording medium, is monitored and individually. There is a method of setting the optimum recording power for the optical recording / reproducing apparatus of the above. However, the amplitude value of the recording signal is not only the recording power, but also the numerical aperture of the optical pickup, the rim intensity (incident to the condensing lens). Of the laser beam, the size and shape of the light spot, and the contamination of the optical system with the lapse of time, the offset usually being about 20% to 40% for each optical pickup. Therefore, the set value of the optimum recording power is largely shifted due to the influence of the offset. For this reason, it is extremely difficult for an optical recording / reproducing apparatus designed for mass production to set the optimum recording power with sufficient accuracy (about 5%) for practical use. Even if the recording power is the same, the recording power level will not be the same even if the recording power is the same, so it is necessary to fine-tune the recording power for each individual optical recording / reproducing device. There was a title.

In an optical recording medium capable of re-recording repeatedly, an optical recording / reproducing apparatus performs test recording on an information track in advance to set an optimum recording power, and then sets an optimum recording power on the information track on which the test recording is performed. On the other hand, the information can be erased and recorded again, or the information can be directly overwritten, so that there is no need to provide a dedicated information track for the test unlike the one-time recording type optical recording medium. However, the risk that the information track was damaged due to excessive recording power in the test recording was inevitable. For this reason, in practice, an extra information track dedicated to the test must be provided and used, and the setting error of the optimum recording power due to the difference in the recording characteristics caused by the error between the positions of the information tracks becomes large. There is a disadvantage that the dedicated information track is wasted for the user.

[0005] The present inventors have previously discussed the effects of offsets of both the recording signal amplitude m and the recording power P, which are likely to occur between individual optical information recording / reproducing devices, or the recording signal amplitude m.
Optimal recording power can be set without being affected only by the offset of an optical information recording / reproducing device designed especially for mass production. An optical information recording / reproducing method capable of eliminating the need for useless test-dedicated tracks for the user and improving the setting accuracy of the optimum recording power has been proposed (JP-A-3-138946). No.). However, in this method, the recording power P is 15 to 18
In order to efficiently perform recording in a high power region of mW, there is still room for improvement.

[0006]

SUMMARY OF THE INVENTION The present invention relates to the conventional optical recording / reproducing method, which is used when recording information in a pattern comprising a low reflectance portion and a high reflectance portion while sequentially changing the recording power P. , And its recording power P is 15 to 1
It is an object of the present invention to provide a method capable of efficiently performing recording in a high power region including 8 mW and an optical recording medium used for the method.

[0007]

The present inventors have conducted intensive studies to further improve the above-mentioned conventional method.
Succeeded in efficiently test-recording information in a pattern composed of a low-reflectance portion and a high-reflectance portion while sequentially changing the recording power P in a high recording power region of １８18 mW,
The present invention has been completed. That is, according to the present invention, an optical recording / reproducing method described below and an optical recording medium used therefor are provided.

(1) By irradiating a laser beam onto an optical recording medium, a phase change is caused in a recording layer of the optical recording medium to record and reproduce information on and from the optical recording medium;
In a rewritable optical recording / reproducing method, information is tested in a pattern including a low reflectance portion and a high reflectance portion while sequentially changing the recording power P in the area including 15 to 18 mW with respect to the optical recording medium. The recorded information is reproduced, the recorded information is reproduced, the recording signal amplitude m corresponding to the recording power P is monitored, and the standardized gradient g (P) is obtained.
G (P) = (Δm / m) / (ΔP / P) ΔP: small change amount in the vicinity of P Δm: small change amount in the vicinity of m The standardized slope g (P ) To determine the optimum recording power by evaluating the excess or deficiency of the recording power, set a specific value S selected from the range of 0.2 to 2.0, and set the standardized slope g.
A recording power Ps such that (P) matches S is detected,
An optical recording / reproducing method, wherein an optimum recording power Po is set by multiplying Ps by a specific value R selected from a range of 1.0 to 1.7.

(2) An optical recording medium used in the optical recording / reproducing method of (1), wherein information corresponding to S and R is recorded in advance. (3) In the optical recording medium of (2), 1.2 ≦ S ≦
An optical recording medium, wherein 1.4 and 1.1 ≦ R ≦ 1.3. (4) An optical recording medium used in the optical recording / reproducing method of (1), wherein information corresponding to the Pt is recorded in advance. (5) The optical recording medium according to any one of (2) to (4), wherein PWM recording is possible at a speed of 4.8 m / sec or more and 14.0 m / sec or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. FIG. 1 shows a configuration diagram of the optical recording medium of the present invention. The basic configuration is such that a first protective layer 2, a recording layer 3, a second protective layer 4, a reflective heat radiation layer 5, and an overcoat layer 6 are provided on a substrate 1 having a guide groove.

As a material for the substrate 1, a resin substrate is usually suitable in terms of moldability and cost. Examples of resins 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, etc. Acrylic resins are preferred.

As the material of the recording layer 3, Ag, In, S
Materials containing a quaternary phase-change recording material containing b and Te as the main components have extremely good recording (amorphization) sensitivity / speed, erasure (crystallization) sensitivity / speed, and erasure ratio. Suitable as a material for the recording layer. However, since Ag / In / Sb / Te has an optimum recording linear velocity depending on its composition, it is necessary to adjust the composition according to the recording linear velocity of an optical recording medium using Ag / In / Sb / Te as a recording layer. There is. Further, other elements or impurities can be added to the recording layer material of the present invention for the purpose of further improving the performance and the reliability. Examples include elements (B, N, C, P, Si), O, S, Se, Al, T described in JP-A-5-185732.
i, V, Mn, Fe, Co, Ni, Cu, Zn, Ge,
Preferred examples include Ga, Sn, Pd, Pt, and Au.

The material of the first protective layer 2 and the second protective layer 4 is SiO, SiO ₂ , ZnO, SnO ₂ , Al
Metal oxides such as ₂ O ₃ , TiO ₂ , In ₂ O ₃ , MgO, ZrO ₂ , nitrides such as Si ₃ N 4, AlN, TiN, BN, ZrN, and sulfides such as ZnS, In ₂ S ₃ , TaS ₄ Material, carbides such as SiC, TaC, B ₄ C, WC, TiC, and ZrC, diamond-like carbon, and mixtures thereof. These materials can be used alone as a protective layer, or as a mixture of each other. Further, impurities may be included as necessary. If necessary, the dielectric layer can be multi-layered. However, the first
The melting points of the protective layer and the second protective layer need to be higher than those of the recording layer. As the material of the first protective layer and the second protective layer, various vapor deposition methods, for example, a vacuum deposition method, a sputtering method, a plasma CVD method, and a photo CVD method
It can be formed by a method, an ion plating method, an electron beam evaporation method, or the like. Among them, the sputtering method is excellent in mass productivity, film quality, and the like.

The thickness of the second protective layer 4 is 15 to 45.
nm, preferably 20 to 40 nm. 15n
If the thickness is less than m, the function as a heat-resistant protective layer will not be achieved. Also, the sensitivity is reduced. On the other hand, if it is thicker than 45 nm, when used at a low linear velocity of 1.2 to 5.6 m / s, interface peeling is likely to occur, and the repetitive recording performance also deteriorates.

The material of the reflection heat radiation layer 5 is Al, A
Metal materials such as u, Ag, and Cu, or alloys thereof, and the like can be used. Although the reflective heat radiation layer 5 is not always necessary, it is preferable to provide the heat radiation layer 5 in order to release excessive heat and reduce the heat load on the disk. Such a reflective heat dissipation layer 5 can be formed by various vapor phase growth methods, for example, a vacuum evaporation method, a sputtering method, a plasma CVD method, a photo CVD method, an ion plating method, an electron beam evaporation method, or the like. The thickness of the reflective heat dissipation layer is 70 to 180 nm,
Preferably, the thickness is 100 to 160 nm.

It is desirable that an overcoat layer 6 is provided on the reflective heat radiation layer 5 to prevent oxidation. As the overcoat layer 6, an ultraviolet curable resin produced by spin coating is generally used. An appropriate thickness is 7 to 15 μm. When the thickness is 7 μm or less, an increase in C1 error is observed when a printing layer is provided on the overcoat layer. On the other hand, if the thickness is 15 μm or more, the internal stress becomes large, which greatly affects the mechanical properties of the disk.

The electromagnetic waves used for initializing, recording, reproducing, and erasing the information recording medium of the present invention include laser light, ultraviolet light,
Various things such as visible light, infrared light, and microwave can be adopted. Among them, a small and compact semiconductor laser is most suitable.

FIG. 2 schematically shows an example of a 5T signal of a recording pulse waveform in an embodiment of a phase change optical disk and a phase change type information recording / reproducing apparatus to which the present invention is applied. FIG. 3 shows an example of the optical recording pulse. FIG. 4 is a block diagram showing an embodiment of a phase change type information recording / reproducing apparatus according to the present invention. In the apparatus of the embodiment shown in FIG. 4, a phase change optical recording medium 11 composed of a phase change optical disk is driven to rotate by a driving means 12 composed of a spindle motor, and a recording / reproducing pickup 13 drives a laser as a light source driving means. A light source composed of a semiconductor laser is driven by a drive circuit 14, and the optical recording medium 11 is irradiated with laser light as electromagnetic waves from the semiconductor laser via an optical system (not shown) to change the phase of the recording layer of the optical recording medium. Then, the reflected light from the optical recording medium 11 is received by the recording / reproducing pickup 13 to record / reproduce information on / from the optical recording medium 11.

In the embodiment of the present invention, the recording / reproducing pickup 13 irradiates a laser beam onto the optical recording medium to cause a phase change in the recording layer of the optical recording medium,
An optical recording / reproducing method for recording / reproducing information to / from an optical recording medium and enabling rewriting is included, but a signal to be recorded is modulated by a modulator and recorded on the optical recording medium by a recording / reproducing pickup. Recording means for recording information. Recording means including this pickup records a mark on a recording layer of an optical recording medium so as to record a signal as a mark width, that is, a so-called PW
Information is recorded in the M recording method. The recording means modulates a signal to be recorded by a modulating unit using a clock, for example, by an EFM modulation method suitable for recording information on a rewritable compact disc or an improved modulation method thereof.

The present invention irradiates such a laser beam onto an optical recording medium to cause a phase change in a recording layer of the optical recording medium, thereby recording and reproducing information on and from the optical recording medium; In a rewritable optical recording / reproducing method, a recording power P of 15 to
In a region including 18 mW, information is test-recorded in a pattern composed of a low-reflectance portion and a high-reflectance portion while being sequentially changed, the test-recorded information is reproduced, and the recording power P
Is monitored, and the standardized gradient g (P) is calculated as follows: g (P) = (Δm / m) / (ΔP / P) ΔP: a minute change amount in the vicinity of P Δm: m The optimum recording power is determined by evaluating the recording power based on the standardized gradient g (P), and determining the optimum recording power. A specific value S selected from the range is set, and the standardized slope g is set.
A recording power Ps such that (P) matches S is detected,
An object of the present invention is to provide an optical recording / reproducing method characterized in that the optimum recording power Po is set by multiplying Ps by a specific value R selected from the range of 1.0 to 1.7.

Here, test recording of information on a pattern composed of a low-reflectance portion and a high-reflectance portion while sequentially changing the recording power P on an optical recording medium in an area including 15 to 18 mW is specifically described. In the test recording area of the optical recording medium, 0.5 m
By recording a random EFM pattern while changing the recording power at intervals of W, the portion irradiated with the comb-like pulse in FIG. 3 becomes amorphous and the reflectance becomes low.
The portion irradiated with the e-level DC light is crystallized and the reflectance is increased. By measuring the signal amplitude m of the 13 regions recorded by changing the power, the standardized gradient g (P) is obtained. It means to ask.

Generally, 1 in a phase change type information recording medium
The recording of the signal (the “1” portion of the binary signal) is performed by forming an amorphous portion (amorphous phase) in the recording layer of the phase change type information recording medium. The formation of an amorphous phase in a phase change type information recording medium requires a temperature rise above the melting point of the recording layer and a sufficient cooling rate thereafter. Here, the pulse portion fp raises the temperature of the recording layer of the phase change type information recording medium to a temperature equal to or higher than the melting point to form the head of the recording mark,
The multi-pulse portion mp raises the temperature of the recording layer to form a recording mark intermediate portion, and the pulse portion op cools the recording layer to form a trailing end portion of the recording mark. If the linear velocity of the phase change type information recording medium is varied, the amount of electromagnetic radiation applied to the phase change type information recording medium will change, and the temperature rise above the melting point of the recording layer and the subsequent cooling rate will change. It is effective to appropriately set the temperature rise above the melting point of the recording layer and the subsequent cooling rate by changing the linear velocity of the type information recording medium. On the other hand, when information is recorded on the recording layer of the phase-change type information recording medium by the PWM recording method, information is provided at the edge of the recording mark. In order to avoid obscuration or erasure of the recording portion due to crystallization of the recording portion, heat must be applied to portions of the recording layer other than the portion where recording is desired. As described above, in order to clearly distinguish the temperature rising condition between the portion of the recording layer to be recorded and the portion to be kept at room temperature, it is necessary not to generate excess heat in the recording layer, It is effective to keep the conduction of the heat low. By doing so, the boundary between the recorded portion and the unrecorded portion becomes clear, and a high-quality recorded signal with small jitter can be obtained.

[0023]

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

Example 1 ZnS.SiO ₂ film (90 nm) / Ag / In / Sb / T
e film (18 nm) /ZnS.SiO ₂ film (32 nm) / A
Recording was performed at a recording linear velocity of 12.0 m / sec on a phase change recording medium having a layer structure of 1 alloy film (160 nm). As the optical recording apparatus, an apparatus having a pickup of NA 0.5 and λ 790 nm was used. The recording signal was an EFM modulated input signal. As shown in FIG. 5, S = 1.3, R = 1.
If it is set to 2, Ps = 18 mW, so that the optimum recording power Po = 21.6 mW.

Example 2 The same layer structure as in Example 1 was adopted, where S = 1.25 and R =
The optimum recording power setting parameter information of 1.20 is recorded on the substrate in advance, and the optical recording / reproducing apparatus reads the optimum recording power setting parameter information, and obtains the optimum recording power Po = 21.8 mW using the parameter. Was. As a result, the signal quality was not degraded even by repeated recording, and stable recording could be performed.

[0026]

According to the first aspect of the present invention, the recording signal amplitude m and the recording power P which are likely to be generated between individual optical recording / reproducing apparatuses.
The optimum recording power can be set without being affected by both offsets or the offset of the recording signal amplitude m, and it is particularly suitable for optical recording / reproducing devices designed for mass production with sufficient accuracy for practical use. The recording power can be easily set. According to the second aspect of the present invention, the information corresponding to S and R used in the optical recording / reproducing method of the first aspect is recorded in advance, so that the recording power reflecting the physical recording characteristics of the optical recording medium is selected. In addition, recording can be performed with a recording power capable of obtaining excellent repetitive recording characteristics. According to the invention of claim 3, in the optical recording medium of claim 2, 1.2 ≦ S ≦ 1.4 and 1.1 ≦ R ≦
With 1.3, the error of the signal recorded on the optical recording medium can be made sufficiently small, and the deterioration of the signal quality when repeatedly recorded can be made small. According to the fourth aspect of the present invention, the P used in the optical recording and reproducing method of the first aspect.
Since the information corresponding to t is recorded in the optical recording medium in advance, the optimum recording power can be easily obtained even in various combinations of the optical recording medium and the optical recording / reproducing apparatus. According to the invention of claim 5, in the optical recording medium of claims 2, 3 and 4, 4.8 m / sec or more and 1
Since PWM recording is possible at a speed of 4.0 m / sec or less, high-speed and high-quality signals can be stably recorded.

[Brief description of the drawings]

FIG. 1 shows an explanatory configuration diagram of an optical recording medium of the present invention.

FIG. 2 is an explanatory diagram schematically showing a recording wave pulse waveform 5T signal in a phase change optical disk and a phase change type information recording / reproducing apparatus to which the present invention is applied.

FIG. 3 is a diagram illustrating an example of an optical recording pulse.

FIG. 4 is a block diagram showing an embodiment of a phase change type information recording / reproducing apparatus according to the present invention.

FIG. 5 shows a correlation diagram between values S and m when determining an optimum recording power.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 1st protective layer 3 recording layer 4 2nd protective layer 5 reflective heat dissipation layer 6 overcoat layer 11 optical recording medium 12 drive means 13 recording / reproducing pickup

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5D090 AA01 BB04 CC14 CC18 EE01 GG33 JJ12 KK03 5F073 BA05 EA13 GA12 GA38

Claims (5)

[Claims] 1. A laser beam is applied to an optical recording medium to cause a phase change in a recording layer of the optical recording medium, so that information on the optical recording medium can be recorded, reproduced, and rewritten. In the optical recording / reproducing method, information is test-recorded on the optical recording medium while sequentially changing the recording power P in a region including 15 to 18 mW, in a pattern including a low reflectance portion and a high reflectance portion. The recorded information is reproduced, the recording signal amplitude m corresponding to the recording power P is monitored, and the standardized gradient g (P) is calculated as g (P) = (Δm / m) / (ΔP / P) ΔP: Small change amount in the vicinity of P Δm: Small change amount in the vicinity of m The optimum recording power is determined by evaluating the recording power based on the standardized gradient g (P). With , A specific value S selected from the range of 0.2 to 2.0 is set, and the standardized slope g is set.
A recording power Ps such that (P) matches S is detected,
An optical recording / reproducing method, wherein an optimum recording power Po is set by multiplying Ps by a specific value R selected from a range of 1.0 to 1.7. 2. An optical recording medium used in the optical recording / reproducing method according to claim 1, wherein information corresponding to S and R is recorded in advance. 3. The optical recording medium according to claim 2, wherein
An optical recording medium, wherein ≦ S ≦ 1.4 and 1.1 ≦ R ≦ 1.3. 4. An optical recording medium used in the optical recording / reproducing method according to claim 1, wherein information corresponding to the Pt is recorded in advance. 5. The optical recording medium according to claim 2, wherein PWM recording is possible at a speed of 4.8 m / sec or more and 14.0 m / sec or less.