JP2002358645A - Recording method, recording device and phase change type optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the lowering of the quality of a recording signal when information is rewritten to a phase change type optical recording medium. SOLUTION: A trial writing is performed to the phase change type optical recording medium while the output power of a light emitting element is changed. The optimum recording power obtained based on a reproducing signal in an area where the trial writing is performed and the output power corresponding to the asymmetry judged to be in a prescribed range previously set are compared with each other to judge whether the optimum recording power is in a suitable range or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method, a recording apparatus, and a phase change type optical recording medium.

[0002]

2. Description of the Related Art For example, a CD-R (Compact Disk Record)
There are large-capacity information recording media such as Able) and CD-RW (Compact Disk ReWritable).

[0003] Above all, phase-change optical recording media such as CD-RW in CD format and DVD-RW and DVD + RW in DVD (Digital Versatile or Video Disc) format have the convenience that information can be rewritten a plurality of times. Due to its height, it is expected to spread widely in the future.

A recording apparatus for recording information on a phase change type optical recording medium includes a light emitting element for emitting a laser beam. In a recording apparatus, information can be recorded or reproduced by a single light emitting element by appropriately changing the output power of laser light emitted from the light emitting element. Thereby, high convenience can be provided to the user.

However, for example, it is assumed that the output power of the light emitting element for recording information becomes inappropriate for the target phase change type optical recording medium due to a difference in the specifications of the recording apparatus. There is a concern that the recording quality of the phase-change optical recording medium will be degraded. There is a concern that such a problem may occur due to a variation in the quality of the phase change optical recording medium.

For this reason, conventionally, when a phase change type optical recording medium is inserted or when recording on a phase change type optical recording medium is started,
Test writing is performed on the target phase-change optical recording medium, and the optimum recording power is obtained based on the characteristics of the reproduction signal obtained by reproducing the test writing area. There are recording devices that perform recording / reproduction or overwriting.

In such a recording apparatus, for example, a method of obtaining an optimum recording power for a CD-RW, which is a typical phase-change optical recording medium, is disclosed in Japanese Patent No. 0308551.
Or the gamma curve method disclosed in Japanese Patent No. 03124721 is used to obtain the optimum recording power.

Here, the γ curve method is to derive a curve called a γ curve derived from a change amount of a recording signal amplitude, which is a difference between signal amplitudes, and to evaluate whether recording power is excessive or insufficient based on the curve. The method is used to obtain the optimum recording power for CD-RW and the like.

[0009]

By the way, as described above, the γ curve method is a method for obtaining an optimum recording power based on a γ curve derived from a change amount of a recording signal amplitude which is a difference between signal amplitudes. The derived γ curve depends on the measurement accuracy of the amplitude of the reproduced signal, the recording quality of the reproduced signal, the amount of change in the output power of the light emitting element during test writing, and the like.

For this reason, depending on the measurement accuracy of the amplitude of the reproduced signal, the recording quality of the reproduced signal, the amount of change in the output power of the light emitting element during test writing, etc., the γ curve deviated from the ideal curve. It is feared that the optimum recording power will be obtained based on this, and that the reliability of the optimum recording power will be reduced.

An object of the present invention is to provide a recording method, a recording apparatus, and a phase-change optical recording medium capable of suppressing a decrease in the quality of a recording signal when information is rewritten.

[0012]

According to a first aspect of the present invention, there is provided a recording method, comprising: changing an output power of a light emitting element of a recording apparatus for optically recording and reproducing information on a phase change type optical recording medium; Trial writing on a phase change optical recording medium,
An optimum recording power is obtained based on a reproduction signal in a test-written area of the phase change type optical recording medium, and the RF of the reproduction signal fluctuates according to a change in output power of the light emitting element.
It is determined whether the asymmetry (Asymmetry) obtained based on the signal and representing the difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark is in a predetermined range, and the asymmetry is determined. When it is determined that the optimum recording power is within a predetermined range, the optimum recording power is determined to be within an appropriate range.

Therefore, it is possible to determine, for each recording device, whether or not the optimum recording power obtained based on the reproduction signal from the test-written area is within an appropriate range.

According to a second aspect of the present invention, in the recording method of the first aspect, the optimum recording power is obtained by using a γ curve method.

Therefore, it is possible to easily apply the present invention to a recording apparatus that obtains the optimum recording power by using the γ-curve method that is already widely used.

The third aspect of the present invention is the first or second aspect.
In the recording method described above, the light emitting element optically records information by outputting a recording power to the phase-change optical recording medium and outputs an erasing power different from the recording power to thereby optically record information. When performing the test writing on the phase-change optical recording medium in which a parameter for obtaining the optimum recording power is stored, based on the parameter. Then, only the recording power is changed as the output power while the erasing power obtained is fixed.

Therefore, if the erasing power is fixed, it is determined whether the optimum recording power is within an appropriate range based on the asymmetry in which the variation with respect to the variation of the output power is made larger than when the erasing power is changed. It is possible to determine whether or not.

According to a fourth aspect of the present invention, in the recording method according to the first, second or third aspect, the asymmetry is based on a linear approximation formula showing a relationship between each of the output powers distributed in a plurality of stages and the asymmetry. Is in a predetermined range set in advance.

Therefore, it is possible to determine whether or not the optimum recording power is within an appropriate range, based on the relationship between the output power and the asymmetry expressed linearly.

According to a fifth aspect of the present invention, in the recording method according to the first, second or third aspect, the asymmetry includes:
Obtained by measurement.

Therefore, it is possible to determine whether or not the optimum recording power is within an appropriate range based on the relationship between the output power and the asymmetry based on the actually measured value.

The invention according to claim 6 is the first or second invention.
6. In the recording method according to 3, 4, or 5, when it is determined that the asymmetry is not within the predetermined range, the optimum recording power is obtained again.

Therefore, the optimum recording power can be reliably set within a predetermined range.

According to a seventh aspect of the present invention, there is provided a recording apparatus which emits a laser beam for irradiating the phase change type optical recording medium, a rotation driving means for driving the phase change type optical recording medium to rotate, Test writing means for rotating the phase-change optical recording medium by rotation driving means to change the output power of the light emitting element to perform test writing on the phase-change optical recording medium; and An optimal recording power acquisition unit for acquiring an optimal recording power based on a reproduction signal in a test-written area of the medium; and a longest recording based on an RF signal of the reproduction signal that varies according to a change in output power of the light emitting element. Asymmetry obtaining means for obtaining an asymmetry (Asymmetry) representing the difference between the amplitude center value of the mark and the amplitude center value of the shortest recording mark, and the asymmetry obtaining means obtained by the asymmetry obtaining means Symmetry is anda asymmetry determination means for determining whether the optimum recording power is within a proper range by determining whether the predetermined range set in advance.

Therefore, the phase change type optical recording medium is rotated by the rotation driving means, and the output power of the light emitting element is changed by the test writing means to perform test writing on the phase change type optical recording medium. The optimum recording power is obtained by the optimum recording power obtaining means based on the reproduction signal in the test-written area of the recording medium, and the asymmetry obtaining means is obtained based on the RF signal of the reproduction signal that fluctuates according to the change in the output power of the light emitting element. The asymmetry determination means determines whether or not the acquired asymmetry is within a predetermined range, thereby determining whether or not the optimum recording power is within an appropriate range. by this,
For each recording device, it is possible to determine whether or not the optimum recording power obtained based on the reproduction signal from the test-written area is within an appropriate range.

According to an eighth aspect of the present invention, in the recording apparatus according to the seventh aspect, the optimum recording power obtaining means obtains the optimum recording power using a γ curve method.

Therefore, the control method can be easily constructed by obtaining the optimum recording power using the γ curve method which is already widely used.

The invention according to claim 9 is the invention according to claim 7 or 8.
In the recording apparatus described above, the light-emitting element optically records information by outputting recording power to the phase-change optical recording medium and outputs an erasing power different from the recording power, thereby optically recording information. At the time of performing the test writing on the phase-change optical recording medium in which the parameters for obtaining the optimum recording power are stored. And only the recording power is changed as the output power.

Therefore, by fixing the erasing power by the test writing means and changing only the recording power as the output power, the erasing power is changed as compared with the case where the erasing power is changed.
It is possible to determine whether or not the optimum recording power is within an appropriate range based on asymmetry in which the amount of change with respect to the amount of change in output power is increased.

According to a tenth aspect of the present invention, in the recording apparatus of the seventh, eighth or ninth aspect, the asymmetry determining means includes a linear approximation indicating a relationship between each of the output powers divided into a plurality of stages and the asymmetry. It is determined whether or not the asymmetry is within a predetermined range based on the equation.

Therefore, the relationship between the output power obtained by the asymmetry obtaining means and the asymmetry becomes linear, and it is possible to determine whether or not the optimum recording power is within an appropriate range based on this asymmetry. .

According to an eleventh aspect of the present invention, in the recording apparatus according to the seventh, eighth or ninth aspect, the asymmetry is obtained by measurement.

Therefore, it is possible to determine whether or not the optimum recording power is within an appropriate range based on the relationship between the output power and the asymmetry based on the actually measured value.

According to a twelfth aspect of the present invention,
12. The recording apparatus according to 9, 10, or 11, further comprising an optimum recording power reacquiring means for acquiring the optimum recording power again when the asymmetry judging means judges that the asymmetry is not within the predetermined range.

Therefore, it is possible to set the optimum recording power within a predetermined range without fail.

The phase-change recording medium according to the invention of claim 13 is used in the recording apparatus according to any one of claims 7 to 12, and is composed of Ag or Ge or Ag and Ge, In.
Or Ga or In and Ga, Sb, Te, N or O
Are included as constituent elements, and the respective composition ratios α, β, γ,
δ and ε (atomic%) are 0 <α ≦ 6 (Ag or Ge or Ag and Ge), 3 ≦ β ≦ 15 (In or Ga or In and Ga), 50 ≦ γ ≦ 90 (Sb), 20 ≦ δ ≦ 3
5 (Te), 0 ≦ ε ≦ 5 (N or O), α + β + γ +
δ + ε + ζ = 100 (where ζ: atomic% of other constituent elements).

Therefore, it is possible to stably obtain the signal level of the reproduced signal in the test-written area for each changed output power.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. This embodiment shows an example of application to an optical information recording / reproducing apparatus that records information on a recordable phase-change optical information recording medium such as a CD-R / RW as a recording apparatus.

FIG. 1 is a front view showing a basic configuration example of the optical information recording / reproducing apparatus of the present embodiment. The optical information recording / reproducing apparatus 1 has an LD 3 as a light emitting element which is driven by an LD (Laser Diode) modulation circuit 2 and emits a laser beam. The laser light emitted from the LD 3 is supplied to a collimator lens 4, a beam splitter 5, and an objective lens 6.
Is applied to the phase-change type optical information recording medium 7 in a condensed state via a laser beam, and is rotationally driven in a plane direction orthogonal to the laser beam irradiated by a spindle motor (not shown) as a rotary drive means. It is used for recording, trial writing, reproducing, and erasing information on the optical information recording medium 7.

As the phase-change type optical information recording medium 7, for example, CD-R / RW, DVD-RW, DVD + RW, D
There are various optical recording media, such as VD-RAMs, which use a phase-change material that changes on the recording layer by laser light irradiation.

Although a detailed illustration and detailed description of the structure of the phase change type optical information recording medium 7 are omitted because it is a known technique, the phase change type optical information recording medium 7 of this embodiment is omitted.
Has a recording layer formed of an Ag-In-b-Te-based phase change recording material. Ag-In-b on the recording layer
It has been confirmed by experiments and the like that the recording sensitivity can be favorably maintained by using the -Te phase change type recording material. Further, Ag-In-b-Te is added to the recording layer.
It has been confirmed by experiments and the like that the use of a system phase-change recording material can maintain excellent characteristics with little signal degradation even after about 1,000 overwrite recordings.

Specifically, the recording layer of the phase-change optical information recording medium 7 of the present embodiment includes Ag or Ge or Ag and Ge, In or Ga or In and Ga, Sb, Te,
N or O is contained as a constituent element. The respective composition ratios α, β, γ, δ, and ε (atomic%) of the respective constituent elements are as follows:
0 <α ≦ 6 (Ag or Ge or Ag and Ge), 3 ≦
β ≦ 15 (In or Ga or In and Ga), 50 ≦
γ ≦ 90 (Sb), 20 ≦ δ ≦ 35 (Te), 0 ≦ ε ≦
5 (N or O), α + β + γ + δ + ε + ζ = 100
(However, ζ: atomic% of other constituent elements).

As a result, the level of each recording signal of the reproduced signal is stabilized, and for example, asymmetry (Asymmetr
It becomes easy to accurately measure recording characteristics such as y).

In particular, it was found that by substituting part or all of Ag with Ge and substituting part or all of In with Ga, the recording linear velocity can be increased and the storage reliability can be improved. And so on.

In the optical information recording / reproducing apparatus 1, the reflected light from the phase-change type optical information recording medium 7 passes through the objective lens 6 again, and the path is bent at a right angle by the beam splitter 5.
The light receiving element 9 receives light via the detection lens 8.

The light receiving element 9 outputs a detection signal corresponding to the received laser beam via the head amplifier 10 to the controller 1.
Output to 1 The controller 11 includes the light receiving element 9
For example, an RF signal (see FIG. 2) of the reproduced signal is taken in from the detection signal output from the.

The controller 11 also controls the driving of the LD modulation circuit 2.

In addition, although not particularly shown, the controller 11 has a microcomputer including a CPU, a ROM, a RAM, and the like. The microcomputer calculates I11t, I11b, I3 from the RF signal of the reproduction signal in the test writing area described later.
of t and I3b (both are described later), a function of measuring and digitizing necessary signal levels, a function of calculating M11 described later and an asymmetry described later from each signal level,
11 for calculating the optimum recording power for the phase-change optical information recording medium 7 from Asymmetr
It has a function of acquiring y, a function of comparing the acquired Asymmetry with a range set in the optical information recording / reproducing device, and the like.

Further, the microcomputer determines the type, maker, product number, etc. of the recording medium based on the laser beam input to the controller 11, or calculates an erasing power Pe described later based on the determined information. Has functions.

In the optical information recording / reproducing apparatus 1, when recording information, the controller 11 generates a pulse control signal based on the recording data, and the LD modulation circuit 2 drives the LD 3 with a drive current corresponding to the pulse control signal. At the same time, the phase change optical information recording medium 7 is rotated by the spindle motor. As a result, laser light is emitted from the LD 3 toward the phase-change optical information recording medium 7, and the laser light changes the phase of the recording layer according to the recording data, thereby recording information.

In the optical information recording / reproducing apparatus 1, at the time of reproduction, the LD modulation circuit 2 drives the LD 3 so as to emit light with reproduction power, and rotates the phase-change optical information recording medium 7 by the spindle motor. As a result, laser light is emitted from the LD 3 toward the phase-change optical information recording medium 7, and information is read according to the laser light reflected from the recording layer.

The configuration required for the optical information recording / reproducing apparatus 1 of the present invention is not limited to a CD-R / RW drive, but may be a DVD-R drive, DVD-RW drive, DV
It can be easily realized in D + RW drive,
-R / RW, DVD-R, DVD-RW, DVD + RW
And the like, while maintaining high recording / reproducing compatibility of various recording media.

Next, the acquisition of the optimum recording power executed by controlling the driving of each part of the optical information recording / reproducing apparatus 1 by the controller 11 of the optical information recording / reproducing apparatus 1 will be described. Here, the acquisition of the optimum recording power when a CD-RW (hereinafter, described with reference numeral 7) is used as the phase change type optical information recording medium 7 will be described.

First, the information recorded on the CD-RW 7 is read, and the erasing power is obtained based on the read information. Here, the method of acquiring the erasing power is, for example, C
The appropriate erasing power is associated with the type, manufacturer, product number, etc. of the D-RW 7 and stored in the controller 11 or the like in advance, and the type of the CD-RW 7 is determined based on the read information.
The manufacturer and product number may be determined, and the erase power corresponding to the determined type, manufacturer, and product number of the CD-RW 7 may be obtained. Further, for example, the erasing power may be obtained by calculation based on the read information.

In this embodiment, the CD-RW 7 has been described as a phase-change optical recording medium, but the present invention is not limited to this. In the phase change optical recording medium other than the CD-RW7, parameters necessary for selecting the optimum recording power in order to eliminate variations in the recording quality of the phase change optical recording medium and the optical information recording / reproducing apparatus are also provided. Since the information is often recorded, the erasing power can be calculated based on the recorded parameters even in a phase-change optical recording medium other than the CD-RW7.

Subsequently, the output power output from the LD 3 is divided into a plurality of stages, and the LD modulation circuit 2 changes the output power of the laser beam output from the LD 3 according to the output power divided into the plurality of stages. By performing the drive control, test writing is performed on the CD-RW 7. Here, the function as the trial writing means is realized.
Hereinafter, the output power output from the LD 3 during information recording and test writing is referred to as recording power.

In this embodiment, test writing is performed while the erase power obtained from the CD-RW 7 is fixed.

The test writing may be performed on a test writing area (power calibration area) (not shown) provided on the inner peripheral side of the CD-RW 7, or may be performed on a normal information recording area. You may go. When performing test writing on an area for recording normal information, it is necessary to erase the test-written information when recording normal information.

An LD is written for the CD-RW7 on which the test is written.
3 outputs a laser beam having an output power preset for reproduction (hereinafter referred to as reproduction power) from the LD 3 to reproduce the test-written area of the CD-RW 7.

The amplitude M11 of the recording signal is calculated by the equation (1) based on the RF signal (see FIG. 3) of the reproduction signal when reproducing the test-written area of the CD-RW 7.

M11 = (I11t−I11b) / I11t (1) where I11t: the maximum amplitude value of the longest recording mark or the longest space I11b: the minimum amplitude value of the longest recording mark or the longest space

Further, based on the RF signal of the same reproduced signal, Asymmetry, which is the difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark, is calculated by equation (2).

Asymmetry = {(I3t + I3b) / 2− (I11t + I11b) / 2} / (I11t−I11b) (2) where I3t: the shortest recording mark or the maximum amplitude value of the shortest space I3b: the shortest recording mark or Minimum amplitude value of shortest space

In a CD (CD-R / RW), when data is recorded, an EFM (Eightto Fourteen Modula
A modulation method called a pulse is used, and the shortest data length is 3T and the longest data length is 11T.

The optimum recording power is calculated by the γ-curve method based on each recording power distributed in a plurality of stages and M11 calculated by the equation (1). Here, the function as the optimum recording power obtaining means is realized.

The γ curve method is a method for obtaining the optimum recording power from the amount of change in the recording signal amplitude, and is widely used when obtaining the optimum recording power for the CD-RW 7. In the γ curve method, γ is calculated based on the difference between the recording signal amplitudes.
A curve called a curve is derived, and based on this curve, excess or deficiency of the recording power is evaluated.

Specifically, the γ curve can be obtained based on the recording signal amplitude M when the recording power is varied, the amount of change ΔM, the recording power Pw, and the amount of change ΔPw. , (3), and is represented as a curve (γ curve) shown in FIG.

Γ = (ΔM / M) / (ΔPw / Pw) (3)

In general, γ in equation (3) is calculated as ΔPw when the recording power is discretely changed and ΔM when the measured M difference is ΔM.

From the obtained γ curve, a recording power corresponding to a recording signal level satisfying a preset reference value is obtained as an optimum recording power. Here, the reference value means a recording signal level within a range in which the quality of the recording signal is favorably maintained.

By using the γ-curve method in obtaining the optimum recording power for the CD-RW 7, information can be recorded with the recording power Pw set so that the normalized γ becomes the same, and different optical information can be recorded. Even when information is recorded by the recording / reproducing apparatus 1, the information can always be recorded in the same recording state.

However, the measurement accuracy of the recording signal amplitude,
The γ curve based on the calculated γ may vary from the ideal curve due to errors such as the recording quality of the recording signal and the amount of change in the recording power at the time of test writing. Therefore, when the optimum recording power is obtained using only the γ curve method for obtaining the optimum recording power based on the γ curve derived from the difference between the signal amplitudes, the reliability of the obtained optimum recording power is poor. Is concerned.

On the other hand, in the present embodiment, a linear approximation formula (see FIG. 5) is obtained based on the recording powers divided into a plurality of stages and the Asymmetry calculated by the formula (2). Based on the obtained linear approximation formula, γ shown in FIG.
Corresponds to the optimum recording power obtained based on the curve
Get Asymmetry. Here, a function as an asymmetry acquisition unit is realized.

Here, FIG. 5 is a correlation diagram showing a relationship between Asymmetry obtained from the same recording signal and recording power. As can be seen from FIG. 5, Asymmetry fluctuates almost linearly with the recording power. Since the asymmetry fluctuates almost linearly with the recording power, a linear approximation that shows the relationship between each recording power and the asymmetry, which is obtained by the calculation of Expression (2) and is divided into a plurality of stages, is secured with high accuracy. be able to.

Finding that Asymmetry fluctuates almost linearly with the recording power, and obtaining a linear approximation equation based on each recording power divided into a plurality of stages and Asymmetry calculated by equation (2). Thus, it is possible to shorten the calculation time for obtaining the linear approximation formula and simplify the calculation process.

Further, it is determined whether or not the acquired Asymmetry is within a predetermined appropriate range. Here, a function as an asymmetry determination unit is realized.

When it is determined that the acquired Asymmetry is within a predetermined appropriate range, it is determined that the optimum recording power is within the appropriate range, and the optimum recording power is determined by the optical information recording / reproducing apparatus 1. Set to.

As a result, it is possible to determine whether or not the optimum recording power obtained based on the γ curve is correct. If the optimum recording power is obtained using only the γ curve method, there is a concern about the optimum recording power. It is possible to improve the reliability of the optimum recording power without causing inconvenience such as a decrease in the reliability.

In addition, with the increase in the recording linear speed accompanying the recent increase in the recording speed, it is possible to suppress the deterioration of the recording quality at the time of a plurality of overwrites, which has been a concern in the past.

On the other hand, when it is determined that the acquired Asymmetry is not within the preset proper range, the acquired
The same process is repeated until it is determined that Asymmetry is within a predetermined appropriate range. Here, the function as the optimum recording power reacquisition means is realized.

As a result, the optimum recording power can be set within a certain set range, and the reliability of the obtained optimum recording power can be further improved.

In addition, in this embodiment, at the time of test writing, the erasing power recorded on the CD-RW 7 is read, and the read erasing power is fixed, and only the recording power is changed.

FIG. 6 is a correlation diagram showing the amount of fluctuation of Asymmetry with respect to the fluctuation of recording power. In FIG. 6, a straight line A represents Asym when the erasing power and the recording power are varied.
In FIG. 6, a straight line B indicates an Asymme when the erasing power is fixed and only the recording power is changed.
Shows the variation of try. As can be seen from FIG. 6, the variation (gradient) of Asymmetry with respect to the variation of the recording power when the erasing power is fixed and only the recording power is varied is the case where the erasing power and the recording power are varied. A
Greater than the fluctuation of symmetry.

That is, when the amount of change is the same, the asymmetry for the change in the recording power is larger when the erasing power is fixed and only the recording power is changed than when the erasing power and the recording power are changed. Since the fluctuation amount of the recording power becomes large, the accuracy of checking the appropriateness of the recording power can be further improved.

In the present embodiment, the optimum recording power is calculated by using the γ curve method. However, the quality of the recording power can be determined by using the characteristic that Asymmetry can be approximated to the recording power in a straight line. Any method can be used as long as it is possible, and the method for calculating the optimum recording power is not limited to this.

In general, in a recording signal of an optical recording medium having a shortest recording mark and a large minimum space, the difference between the amplitude center value of the longest recording mark and the shortest recording mark is determined by the top of the longest recording mark obtained by AC-coupling the reproduction signal. And the signal characteristic β may be measured from the bottom level. If the shortest recording mark and space are larger than marks and spaces of other lengths, this β can be used as a substitute characteristic of Asymmetry.

Next, in order to confirm the effect of the present invention, γ
Comparison experiment when the standard deviation of the optimum recording power obtained using the comparison between the curve method and Asymmetry (Example 1) and the optimum recording power obtained using only the γ curve method (Comparative Example 1) is compared explain.

In the experiment, a CD-RW “CD-RW 74-” manufactured by Ricoh Co., Ltd. was used as the phase-change optical information recording medium 7.
AZ2 ″, a CD-R / RW drive MP7040A manufactured by Ricoh Co., Ltd. was used as the optical information recording / reproducing apparatus 1. The recording linear velocity at the time of trial writing in the optical information recording / reproducing apparatus 1 was 4 × CD speed, and recording power and erasing power Were written at a fixed ratio.

Further, the RF from the MP7040A substrate
The signal is output as a playback signal, and based on the RF signal,
Each signal level was calculated based on the amplitude value of the reproduced signal, the center value of the amplitude of the longest recording mark, and the center value of the amplitude of the shortest recording mark measured using an oscilloscope manufactured by ronix.

The optimum recording power is as follows: Optical information recording / reproducing apparatus 1: The recording power in MP7040A is 13.0 ± 0.3 m.
Assuming W, the range of Asymmetry is -7.95 or more.
The determination was made by setting the value to 75 or less. The number of samples is 50.

[0091]

[Table 1]

Table 1 shows the results of comparison between Example 1 and Comparative Example 1. The standard deviation of the recording power at the optimum recording power obtained using only the γ curve method (Comparative Example 1) is 0.3.
70, the standard deviation of the optimum recording power (Example 1) obtained using the comparison between the γ curve method and Asymmetry is 0.21, and the optimum recording power using the comparison between the γ curve method and Asymmetry is obtained. It can be seen that the variation of the optimum recording power is suppressed by obtaining the value of.

Next, under the same experimental conditions as described above, when the erasing power is fixed and only the recording power is changed, the optimum recording power obtained using the γ-curve method and the comparison of Asymmetry (Example 2) A description will be given of a comparative experiment in which the standard deviation is compared with the optimum recording power obtained by using only the γ curve method (Comparative Example 2).

Here, test writing is performed by fixing the erasing power Pe calculated by the equation (4) based on the parameters of the recording linear velocity Pind, ρ, and ε read from the substrate information recorded on the CD-RW. Was done.

Pe = Pind * ρ * ε (4)

In the CD-RW7 used in this embodiment, Pi
nd: 10 mW, ε: 0.5, ρ: 1.2, and Pe =
6.0 mW.

The optimum recording power is as follows: the optical information recording / reproducing apparatus 1: the recording power in MP7040A is 13.0 ± 0.3 m.
Assuming W, the range of Asymmetry is -11.0 or more and -8.
It was set to 5 or less and judged. The number of samples is 50.

[0098]

[Table 2]

Table 2 shows the results of comparison between Example 2 and Comparative Example 2. The standard deviation of the recording power at the optimum recording power obtained using only the γ curve method (Comparative Example 2) is 0.3.
68, the standard deviation of the optimum recording power (Example 2) obtained using the comparison between the γ curve method and Asymmetry is 0.15, and the optimum recording power using the comparison between the γ curve method and Asymmetry is obtained. It can be seen that the variation of the optimum recording power is suppressed by obtaining the value of.

[0100]

According to the recording method of the present invention, the output power of the light emitting element of the recording device for optically recording / reproducing information on / from the phase-change type optical recording medium is changed to change the phase change. Test writing is performed on the optical recording medium, and the optimum recording power is obtained based on the reproduction signal of the test-written area of the phase-change optical recording medium, and the optimum recording power is changed according to the change in the output power of the light emitting element. The asymmetry (A) which is obtained based on the RF signal of the reproduction signal and represents the difference between the amplitude center value of the longest recording mark and the
(symmetry) is determined to be within a predetermined range, and when it is determined that the asymmetry is within a predetermined range, it is determined that the optimum recording power is within an appropriate range. This makes it possible to determine whether or not the optimum recording power obtained based on the reproduction signal from the test-written area is within an appropriate range for each recording device. Information can be recorded with the recording power. As a result, it is possible to suppress a decrease in the quality of the recording signal when rewriting information on the phase-change optical recording medium.

According to a second aspect of the present invention, in the recording method according to the first aspect, the optimum recording power is obtained by using a γ-curve method, thereby using a γ-curve method which is already widely used. Therefore, it is possible to easily apply the present invention to a recording apparatus that obtains an optimum recording power.

According to a third aspect of the present invention, in the recording method according to the first or second aspect, the light emitting element optically records information by outputting recording power to the phase-change optical recording medium. And the phase change type light having a function of optically erasing information by outputting an erasing power different from the recording power, wherein a parameter for obtaining the optimum recording power is stored. When performing the test writing on the recording medium, the erasing is performed by fixing the erasing power obtained based on the parameter, changing only the recording power as the output power, and fixing the erasing power. The optimum recording power is within the appropriate range based on the asymmetry that makes the variation with respect to the variation of the output power larger than when the power is changed. Since it is possible to determine whether there, it is possible to improve the accuracy of the determination of the optimum recording power.

According to the invention set forth in claim 4, according to claim 1,
4. In the recording method according to item 2 or 3, it is determined whether or not the asymmetry is within a predetermined range based on a linear approximation formula indicating a relationship between each of the output powers and the asymmetry allocated to a plurality of stages. As a result, it is possible to improve the determination accuracy of the optimum recording power and to speed up and simplify the determination process.

According to the fifth aspect of the invention,
4. The recording method according to item 2 or 3, wherein the asymmetry is obtained by measurement to determine whether or not the optimum recording power is within an appropriate range based on a relationship between output power and asymmetry based on an actually measured value. Therefore, it is possible to obtain an optimum recording power that is more appropriate for actual use.

According to the invention described in claim 6, according to claim 1,
In the recording method according to 2, 3, 4, or 5, when it is determined that the asymmetry is not within the predetermined range,
By obtaining the optimum recording power again, the optimum recording power can be reliably set within a predetermined range.

According to the recording apparatus of the invention described in claim 7,
A light-emitting element that emits a laser beam that irradiates the phase-change optical recording medium; rotation driving means that rotationally drives the phase-change optical recording medium; and rotationally drives the phase-change optical recording medium with the rotation driving means. Test writing means for performing test writing on the phase change type optical recording medium by changing the output power of the light emitting element, and optimally based on a reproduction signal of a test written area of the phase change type optical recording medium. An optimum recording power acquisition unit for acquiring recording power, and an amplitude center value of a longest recording mark and an amplitude center value of a shortest recording mark based on an RF signal of the reproduction signal that fluctuates according to a change in output power of the light emitting element. (Asymmetry)
Determining whether the optimum recording power is within an appropriate range by determining whether the asymmetry obtained by the asymmetry obtaining means is within a predetermined range set in advance. And an asymmetry determining means, wherein a test drive is performed on the phase change optical recording medium by rotating the phase change type optical recording medium by the rotation driving means and changing the output power of the light emitting element by the test writing means. The optimum recording power is obtained by the optimum recording power obtaining means based on the reproduction signal of the test-written area of the phase change type optical recording medium, and the RF signal of the reproduction signal fluctuates according to the change of the output power of the light emitting element. The asymmetry determining means determines whether the asymmetry acquired by the asymmetry acquiring means is within a predetermined range based on the asymmetry. By determining whether or not the optimum recording power is within the proper range, the optimum recording power obtained based on the reproduction signal from the test-written area is determined for each recording device. Since it is possible to determine whether the value is within the range, it is possible to record information with an optimum recording power suitable for rewriting. As a result, it is possible to suppress a decrease in the quality of the recording signal when rewriting information on the phase-change optical recording medium.

According to an eighth aspect of the present invention, in the recording apparatus according to the seventh aspect, the optimum recording power obtaining means is already widely used by obtaining the optimum recording power using a γ curve method. By obtaining the optimum recording power using the γ curve method, the construction of the control method can be facilitated.

According to the ninth aspect of the present invention, in the recording apparatus according to the seventh or eighth aspect, the light emitting element optically records information by outputting recording power to the phase change type optical recording medium. A function for optically erasing information by recording and outputting an erasing power different from the recording power is provided, and the test writing means stores a parameter for obtaining the optimum recording power. When performing the test writing on the phase change type optical recording medium, the erasing power obtained based on the parameter is fixed and only the recording power is changed as the output power, so that the erasing power is fixed and the recording is performed. By changing only the power as the output power, the variation with respect to the change in the output power is larger than when the erase power is changed. Based on the Ku let the asymmetry, the optimum recording power becomes possible to determine whether it is within the proper range, it is possible to improve the accuracy of the determination of the optimum recording power.

According to a tenth aspect of the present invention, in the recording apparatus according to the seventh, eighth or ninth aspect, the asymmetry determining means indicates a relationship between each of the output powers divided in a plurality of stages and the asymmetry. By determining whether or not the asymmetry is within a predetermined range based on a linear approximation formula, it is possible to improve the accuracy of determining the optimum recording power and to speed up and simplify the determination process.

According to the eleventh aspect of the present invention, in the recording apparatus according to the seventh, eighth or ninth aspect, the asymmetry is obtained by measurement, so that the asymmetry is based on the relationship between the output power and the asymmetry based on the actually measured value. Thus, it is possible to determine whether or not the optimum recording power is within an appropriate range, so that it is possible to obtain the optimum recording power that is more appropriate for actual use.

According to the twelfth aspect, the seventh aspect, the eighth aspect,
12. The recording apparatus according to 9, 10 or 11, further comprising an optimum recording power reacquiring means for acquiring the optimum recording power again when the asymmetry judging means judges that the asymmetry is not within the predetermined range. And the optimum recording power can be reliably set within a predetermined range.

According to the phase change recording medium of the present invention, the recording medium is used in the recording apparatus according to any one of claims 7 to 12, and used in the recording apparatus according to claim 7. Ag or Ge or Ag and Ge, In or G
a or In and Ga, Sb, Te, N or O as constituent elements, and their respective composition ratios α, β, γ, δ, ε
(Atomic%) is 0 <α ≦ 6 (Ag or Ge or Ag
And Ge), 3 ≦ β ≦ 15 (In or Ga or In and G
a), 50 ≦ γ ≦ 90 (Sb), 20 ≦ δ ≦ 35 (T
e), 0 ≦ ε ≦ 5 (N or O), α + β + γ + δ + ε
+ Ζ = 100 (however, ζ: atomic% of other constituent elements)
, It is possible to stably obtain the signal level of the reproduction signal in the test-written area for each changed output power. Thereby, the reliability of the recorded signal can be improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a basic configuration example of an optical information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is an eye pattern showing an RF signal of a reproduction signal.

FIG. 3 is a correlation diagram showing a relationship between a recording power and an amplitude of a recording signal.

FIG. 4 is a correlation diagram showing a relationship between γ and recording power.

FIG. 5 is a correlation diagram showing a relationship between Asymmetry and recording power.

FIG. 6 is a correlation diagram showing a variation in Asymmetry with respect to a variation in recording power.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording device 3 Light emitting element 7 Phase change type optical recording medium

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H111 EA03 EA04 EA12 EA23 EA31 FB05 FB09 FB12 FB17 FB21 FB25 FB29 FB30 5D029 JA01 5D090 AA01 BB05 CC01 CC02 DD01 EE02 EE05 JJ12 KK03 5D119 AA23 BA01 BB01

Claims (13)

[Claims] 1. A test writing is performed on the phase-change optical recording medium by changing an output power of a light-emitting element of a recording apparatus that optically records and reproduces information on the phase-change optical recording medium. An optimum recording power is obtained based on a reproduction signal of a test-written area of the phase change optical recording medium, and the optimum recording power is obtained based on an RF signal of the reproduction signal that fluctuates according to a change in output power of the light emitting element. It is determined whether or not asymmetry (Asymmetry) representing the difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark is within a predetermined range, and the asymmetry is within a predetermined range. A recording method in which when it is determined that there is, the optimum recording power is determined to be within an appropriate range. 2. The recording method according to claim 1, wherein the optimum recording power is obtained by using a γ curve method. 3. The light-emitting element records information optically by outputting recording power to the phase-change optical recording medium, and optically outputs erasing power different from the recording power. Has a function of erasing information, and when performing the test writing on the phase change optical recording medium in which a parameter for obtaining the optimum recording power is stored, based on the parameter, 3. The obtained erasing power is fixed, and only the recording power is changed as the output power.
The recording method described. 4. A method according to claim 1, wherein a determination is made as to whether or not the asymmetry is within a predetermined range based on a linear approximation formula indicating a relationship between each of the output powers and the asymmetry allocated to a plurality of stages. 4. The recording method according to 2 or 3. 5. The recording method according to claim 1, wherein the asymmetry is obtained by measurement. 6. The recording method according to claim 1, wherein when it is determined that the asymmetry is not within the predetermined range, the optimum recording power is obtained again. 7. A light emitting element for emitting a laser beam for irradiating a phase change type optical recording medium, a rotation driving unit for driving the phase change type optical recording medium to rotate, and the phase change type light by the rotation driving unit. Test writing means for performing test writing on the phase-change optical recording medium by rotating the recording medium and changing the output power of the light-emitting element; and reproducing a test-written area of the phase-change optical recording medium. An optimum recording power obtaining means for obtaining an optimum recording power based on a signal; and an amplitude center value of a longest recording mark and a shortest recording mark based on an RF signal of the reproduction signal which fluctuates according to a change in output power of the light emitting element. Asymmetry acquisition means for acquiring asymmetry (Asymmetry) representing the difference from the amplitude center value of, and the asymmetry acquired by the asymmetry acquisition means is set in advance. Recording anda asymmetry determination means for determining whether the optimum recording power is within a proper range by determining whether the predetermined range. 8. The recording apparatus according to claim 7, wherein said optimum recording power obtaining means obtains said optimum recording power using a γ curve method. 9. The light-emitting element optically records information by outputting recording power to the phase-change optical recording medium, and optically outputs information by erasing power different from the recording power. A function for erasing information, wherein the test writing means performs the test writing on the phase-change optical recording medium in which the parameters for obtaining the optimum recording power are stored. 9. The recording apparatus according to claim 7, wherein an erasing power obtained based on the recording power is fixed, and only the recording power is changed as the output power. 10. The asymmetry determining means determines whether or not the asymmetry is within a predetermined range based on a linear approximation formula indicating a relationship between each of the output powers distributed in a plurality of stages and the asymmetry. The recording apparatus according to claim 7, wherein the determination is performed. 11. The recording apparatus according to claim 7, wherein the asymmetry is obtained by measurement. 12. An optimum recording power reacquiring means for reacquiring the optimal recording power when the asymmetry determining means determines that the asymmetry is not within the predetermined range. 10 or 1
2. The recording device according to 1. 13. A recording medium according to claim 7, wherein said recording medium is Ag, Ge, or Ag.
And Ge, In or Ga or In and Ga, Sb, T
e, N or O as a constituent element, and each composition ratio α, β, γ, δ, ε (atomic%) is 0 <α ≦ 6 (Ag or Ge or Ag and Ge), 3 ≦ β ≦ 15 (In or Ga or In and Ga), 50 ≦ γ ≦ 90 (Sb), 20 ≦ δ ≦ 35 (Te), 0 ≦ ε ≦ 5 (N or O), α + β + γ + δ + ε + ζ = 100 (where Δ: other configurations) A phase change type optical recording medium having a recording layer set to (atomic% of element).