JP2000030254A - Recording strategy evaluation method and optimum strategy evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording strategy evaluation method and an optimum strategy evaluation device permitting easy determination of a recording strategy which is suitable for each optical information recording medium. SOLUTION: In a recording method for recording marks on an optical information recording medium using recording strategies differing at least to a shortest mark and the other marks, the recording strategies are selected so that a recording power in which jitters containing all recording marks or jitters containing only the shortest recording symbol becomes minimum, so that a recording power, in which a deviation from the theoretical value of the longest recording mark becomes minimum, become approximately equal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording strategy evaluation method and an optimum strategy evaluation device for finding a recording strategy suitable for an optical information recording medium.

[0002]

2. Description of the Related Art As an optical information recording apparatus, there is known an optical information recording apparatus which modulates the light emission power of a laser light source according to a mark recording strategy to record a mark on an optical information recording medium. In this optical information recording apparatus, for example, JP-A-7-22
As disclosed in JP-A-5948 and JP-A-10-64065, the optical information recording medium has many characteristics such as the thermal decomposition characteristic of the recording material, the cohesive state change characteristic, the groove shape of the substrate, the recording density, and the recording linear velocity. The recording strategy is an important factor influencing the recording characteristics because the recording characteristics change depending on the conditions.

In order to minimize jitter, there are many cases where recording power alone cannot be sufficient. In recent years, a signal generator that can arbitrarily change the recording strategy including the relationship between the front and rear marks and spaces has also been marketed. The conventional write strategy evaluation method or write strategy determination method basically focuses on the jitter value and evaluates or determines the write strategy only on the condition that the jitter becomes minimum. There is also a write strategy evaluation method or a write strategy determination method for evaluating the theoretical deviation of each mark or space. However, usually, different write strategies are used depending on the mark length.

[0004]

In the conventional write strategy evaluation method or write strategy determination method, the theoretical deviation of each mark or space may be evaluated, but basically the focus is on the jitter value. Since the recording strategy is evaluated or determined only on the condition that the jitter becomes minimum, even if a long mark such as a synchronization mark has a theoretical deviation depending on the optical information recording medium, it is not evaluated. There is.

A write strategy evaluation method or a write strategy determination method for changing the write strategy so as to optimize the deviation of all the marks from the theoretical values is usually performed by the following method.
Since the recording strategy of the short mark and the long mark is often used separately, the optimization efficiency is low, and there is a possibility that the optimization may be meaningless. In addition, the method of optimizing the crossroads strategy, including the relationship between the front and rear marks and the space, is easy because the number of setting points is very large, the procedure is complicated, and it takes a lot of time. There is a problem that cannot be automated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a recording strategy evaluation method and an optimum strategy evaluation device which can easily determine a recording strategy suitable for each optical information recording medium.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a mark is recorded on an optical information recording medium by using different recording strategies for at least a shortest mark and other marks. In the recording method, the recording power that minimizes the jitter including all the recording marks or the jitter of only the shortest recording mark is substantially equal to the recording power that minimizes the deviation from the theoretical value of the longest recording mark. It is characterized in that a recording strategy is selected.

According to a second aspect of the present invention, there is provided a recording method for recording a mark on an optical information recording medium using a recording strategy, wherein the recording power is changed using an arbitrarily set recording strategy. The amount of deviation of the longest recording mark from the theoretical mark length was measured, and the recording power that minimized this deviation was determined. The recording power of the short mark is continuously changed with the recording power determined in step 2, jitter including all recording marks,
Alternatively, an optimal strategy for a short mark that minimizes the jitter of only the shortest recording mark is determined, and Using the recording strategy determined in step (1), the recording power was changed to measure the amount of deviation of the longest recording mark from the theoretical mark length, and the recording power that minimized this deviation was determined. Until the recording power obtained in step 4 becomes substantially equal to the recording power obtained in step 4, and finally determine a recording strategy in which the recording power obtained in step 4 is substantially equal to the recording power obtained in step 4 as an optimum recording strategy. It is characterized by.

According to a third aspect of the present invention, there is provided an optical information recording apparatus for recording marks on an optical information recording medium using different recording strategies for at least the shortest mark and the other marks, including all recording marks. Means for searching for a recording strategy so that the recording power at which the jitter or the jitter of only the shortest recording mark is minimized is substantially equal to the recording power at which the deviation of the longest recording mark from the theoretical value is minimized. It is a feature.

According to a fourth aspect of the present invention, there is provided an optical information recording apparatus for recording a mark on an optical information recording medium by using a recording strategy.
A first means for measuring the deviation of the longest recording mark from the theoretical mark length by changing the recording power and obtaining a recording power that minimizes the deviation, and a short recording power obtained by the first means. By continuously changing the mark recording strategy,
Second means for determining an optimum strategy for a short mark in which the jitter including all the recorded marks or the jitter of only the shortest recorded mark is minimized, and the recording power is determined by using the recording strategy determined by the second means. The third means for measuring the amount of deviation of the longest recording mark from the theoretical mark length by changing the length of the recording mark, and obtaining the recording power that minimizes this amount of deviation, the recording power obtained by the first means and the third power The first to third means are repeatedly operated until the recording power obtained by the means is substantially equal to the recording power obtained by the first means and the recording power obtained by the third means. And a fourth means for finally determining a recording strategy that is substantially equal to the optimal recording strategy.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A recording strategy evaluation method and an optimum strategy evaluation apparatus according to an embodiment of the present invention provide only a jitter including all recording marks, or a jitter of a shortest recording mark and a deviation amount from a theoretical value of a longest recording mark. There is a feature in using. Basically, since the shortest recording mark having a high recording frequency is less likely to form a recording mark than other recording marks, the recording strategies of the shortest recording mark and other recording marks are generally independent in many cases.

The so-called teardrop-shaped recording mark (asymmetry) of the longest recording mark is most remarkable due to the influence of heat conduction of the recording laser beam. Therefore, the difference in the recording state between the shortest recording mark and the longest recording mark becomes most noticeable. Embodiments of the present invention use this phenomenon to determine an optimum recording strategy.

In the embodiment of the present invention, as the evaluation of the shortest recording mark, the jitter including all the recording marks or the jitter of the shortest recording mark is used. This is because the jitter of the shortest recording mark should be evaluated, but since the frequency of the shortest recording mark is usually the highest, the jitter including all the recording marks greatly depends on the jitter of the shortest recording mark. Either the jitter including all recording marks or the jitter of the shortest recording mark may be used for the convenience of measurement.

The longest recording mark is evaluated based on the amount of deviation from the theoretical value of the longest recording mark. The longest record mark is
Since it is usually used as a synchronization mark, it can be easily distinguished from other recording marks and measurement can be simplified. The reason for not using the jitter of the longest recording mark as the evaluation of the longest recording mark is that the deviation amount from the theoretical value of the recording mark can be measured more stably than the jitter. This is because there is no possibility of interference with the recording mark.

The reason why the deviation of the recording mark width from the theoretical value is not used as the evaluation of the shortest recording mark is that when the recording state is not good (when the jitter is bad), the shortest recording mark is the same as the next longest recording mark. This is because it is difficult to measure both of them independently because they are close to each other in length and length and interfere with each other. That is, when there is interference between the recording marks described above, the average value of the shortest recording marks cannot be measured accurately. The embodiment of the present invention makes it possible to easily determine a recording strategy suitable for each optical information recording medium by using such a recording strategy determination method.

This recording strategy determination method can also be applied to a recording / reproducing drive device. That is, the recording laser beam intensity optimization (OPC: Optimal Power Control) is performed even with the current CD-R or the like.
1) or a system for changing the recording strategy for each optical information recording medium maker is incorporated in a recording / reproducing drive (Japanese Patent Laid-Open No. Hei 8-249662).
This is due to the fact that the optical information recording medium cannot perform the same recording / reproduction under the same recording conditions due to environmental temperature, wavelength fluctuation of the laser light source, and the like.

If the recording strategy determination method according to the embodiment of the present invention is used, more reliable recording can be performed by using the conventional OPC together. The recording strategy determination method according to the embodiment of the present invention is applicable regardless of the type of the optical information recording medium and the recording / reproducing wavelength.

FIGS. 1 and 2 show a recording strategy evaluation method and an optimum strategy evaluation device according to an embodiment of the present invention. This embodiment is an embodiment of the first and third aspects of the present invention. This optimal strategy evaluation device has a recording strategy determining means 1. The optical information recording device rotates the optical information recording medium with a spindle motor and records marks on the optical information recording medium using different recording strategies for at least the shortest mark and other marks. This optical information recording device has a modulator 2, an optical pickup 3, and the like. The recording strategy determining means 1 comprises an optimum recording power determining means 4 based on the longest mark, a minimum jitter recording power determining means 5, a recording strategy determining means 6 and a strategy adjusting means 7, and a recording strategy suitable for each optical information recording medium 8. To determine.

First, the optimum recording power determining means 4 for the longest mark uses the modulator 2 to continuously change the recording power according to the recording strategy arbitrarily set for the longest recording mark.
Output to The modulator 2 changes the recording power of the semiconductor laser as a laser light source in the optical pickup 3 continuously by using a recording strategy set arbitrarily by a signal from the optimum recording power determining means 4 based on the longest mark. Drive modulation. The optical pickup 3 irradiates the optical information recording medium 8 with a laser beam having a recording power from the semiconductor laser via an optical system, and records all recording marks or the shortest recording marks and the longest recording marks on the optical information recording medium 8. Recording is performed, and a laser beam of reproducing power from the semiconductor laser is irradiated on the optical information recording medium 8 through the optical system, and the reflected light is received by the light receiving element through the optical system to obtain a reproduction signal.

The optimal recording power determining means 4 by the longest mark evaluates the longest longest record mark from the reproduction signal for the recorded marks optimum recording power P ₁ from the optical pickup 3, the longest amount of deviation from the theoretical value of the recording mark is minimized the optimum recording power P ₁ to be determined. The jitter minimum recording power determination means 5 determines the recording power P ₂ that minimizes the jitter of only the shortest recording mark (or the jitter including all recording marks) from the reproduction signal of the shortest recording mark (or all recording marks) from the optical pickup 3. to evaluate, determine the recording power P _2.

The recording strategy judging means 6 judges whether the optimum recording power P ₁ obtained by the optimum recording power judging means 4 for the longest mark is substantially equal to the recording power P ₂ obtained by the minimum jitter recording power judging means 5. to decide. The strategy adjusting means 7 changes the set recording strategy and repeats the above procedure if P ₁に よ り P _{2 is} not satisfied according to the judgment result of the recording strategy judging means 6.

As described above, while the recording strategy is changed by the strategy adjusting means 7, the optimum recording power determination means 4 based on the longest mark is used by the optimum recording power judging means 4 to minimize the amount of deviation of the longest recording mark from the theoretical value until P ₁ ≒ P _2. Recording power P ₁
And the recording power P ₂ that minimizes the jitter of only the shortest recording mark (or the jitter including all recording marks) is evaluated by the minimum jitter recording power judging means 5, and the recording strategy judging means 6 evaluates P ₁ ≒ It becomes P ₂ when determining that time recording strategy is set as the optimum recording strategy. According to this embodiment, a recording strategy suitable for each optical information recording medium can be easily obtained.

3 and 4 show a recording strategy evaluation method and an optimum strategy evaluation device according to another embodiment of the present invention. This embodiment is one embodiment of the invention according to claims 2 and 4. FIG. This optimum strategy evaluation device has a recording strategy determining means 11 for rotating the optical information recording medium 8 by a spindle motor. The optical information recording device records a mark on the optical information recording medium 8 using a recording strategy. This optical information recording device has a modulator 2, an optical pickup 3, and the like. The recording strategy determining means 11 comprises an optimum recording power determining means 12 based on the longest mark, a strategy adjusting means 13 for the shortest mark, an optimum recording power determining means 14 based on the longest mark, and a recording strategy determining means 15, and is suitable for the optical information recording medium 8. Determine the recording strategy used.

First, the optimum recording power judging means 12 based on the longest mark outputs a signal for continuously changing the recording power to the modulator 2 using the recording strategy S ₁ arbitrarily set. Modulator 2, the signal from the optimum recording power determining means 12 according to the longest mark, by using the recording strategy S ₁ set arbitrarily, modulates and drives a semiconductor laser as a laser light source in the optical pickup 3. The optical pickup 3 irradiates the optical information recording medium 8 with a laser beam having a recording power from the semiconductor laser via an optical system, and records all recording marks or the shortest recording marks and the longest recording marks on the optical information recording medium 8. Recording is performed, and a laser beam of reproducing power from the semiconductor laser is irradiated on the optical information recording medium 8 through the optical system, and the reflected light is received by the light receiving element through the optical system to obtain a reproduction signal.

The longest mark by the optimum recording power determining means 12 evaluates the maximum amount of deviation from the theoretical value of the longest recording mark in the recording strategy S ₁ from the reproduced signal to the recording marks from the optical pickup 3, in the recording strategy S ₁ the longest recording mark of the optimum recording power P of the longest recording than the amount of deviation from the theoretical value of the recording mark strategy S ₁ of
Decide ₁₀ .

Next, the strategy adjustment means 1 for the shortest mark
3 outputs a signal to the optimum recording power continuously changing the recording strategy of a short mark with the optimum recording power P ₁₀ was determined by determining means 12 according to the longest mark to the modulator 2, modulator 2 strategy adjustment means for the shortest mark The semiconductor laser of the optical pickup 3 is modulated and driven by the signal from 13.

The optical pickup 3 irradiates a laser beam of the recording power from the semiconductor laser to the optical information recording medium 8 via an optical system, and records all recording marks on the optical information recording medium 8.
Alternatively, the shortest recording mark and the longest recording mark are recorded, and a laser beam of reproducing power from the semiconductor laser is irradiated on the optical information recording medium 8 via the optical system, and the reflected light is received by the light receiving element via the optical system. To obtain a reproduction signal. The strategy adjustment means 13 for the shortest mark is an optical pickup 3
Optimum recording power P ₁₀ in jitter that includes all recording marks or jitter of only the shortest recording mark, the reproduction signal from determines the optimum recording strategy S ₂ for short marks is minimized.

Next, the optimum recording power judging means 14 for the longest mark outputs a signal for continuously changing the recording power to the modulator ₂ by using the recording strategy S ₂ determined by the shortest mark strategy adjusting means 13. I do. The modulator 2 receives the signal from the optimum recording power determining means 14 based on the longest mark and uses the shortest mark strategy adjusting means 13
In using the recording strategy S ₂ were determined, modulates and drives to the semiconductor laser of the optical pickup 3 records power changes continuously. The optical pickup 3 irradiates the optical information recording medium 8 with a laser beam having a recording power from the semiconductor laser via an optical system, and records all recording marks or the shortest recording marks and the longest recording marks on the optical information recording medium 8. Recording is performed, and a laser beam of reproducing power from the semiconductor laser is irradiated on the optical information recording medium 8 through the optical system, and the reflected light is received by the light receiving element through the optical system to obtain a reproduction signal.

The optimal recording power determining means 14 according to the longest mark evaluates the longest amount of deviation from the theoretical value of the recording mark in the recording strategy S ₂ from the reproduced signal with respect to the longest recording mark of the optical pickup 3, the recording strategy S ₂ determining the longest recording mark of the optimum recording power P ₂₀ in the longest than the amount of deviation from the theoretical value of the recording mark strategy S ₂ in.

The recording strategy determining unit 15, the optimum recording power P ₁₀ obtained by the optimum recording power determining means 12 according to the longest mark, is substantially equal to the optimum recording power P ₂₀ obtained by the optimum recording power determining means 14 according to the longest mark Determine whether or not. Procedure shortest mark strategy adjustment means 13 which clears the recording strategy S ₂ by changing the optimum recording power unless P ₁₀ ≒ P ₂₀ from P ₁₀ to P _20, again obtains the first recording strategy S ₂ of the short mark Return to.

Therefore, the above-mentioned optimum recording power P ₁₀
In jitter that includes all recording marks, or operation of the jitter of the shortest recording mark only to determine the optimum recording strategy S ₂ for short marks is minimized, the amount of deviation from the theoretical value of the longest recording mark in the recording strategy S ₂ evaluate and longest recording mark of the optimum recording operation for determining the power P _20, whether by determining P ₁₀ ≒ P ₂₀ unless the optimum recording is P ₁₀ ≒ P ₂₀ in the recording strategy S ₂ from the shift amount the power was changed from P ₁₀ to P ₂₀ recording strategy S ₂ was clear operation to continuously change the recording strategy of a short mark again P
Repeat until the ₁₀ ≒ P ₂₀ is carried out.

However, at this time, if P ₁₀ = P ₂₀ is not reached, it may be displayed that there is no optimum recording power, or the initial strategy may be adjusted and the optimum recording power and optimum strategy may be adjusted again. You may ask for it.

The recording strategy determining means 15 determines that P ₁₀ 10P
When it reaches ₂₀ , the recording strategy set at that time is determined as the optimal recording strategy. According to this embodiment, a recording strategy suitable for each optical information recording medium can be easily obtained.

Next, an embodiment of the present invention will be described.
This embodiment is an embodiment of a method for determining an optimum recording strategy according to the present invention.
ons for Recordable Disk (D
VD-R) Part1 PHYSICAL SPECI
FICTIONS Version 1.0 Jul
y Using the recommended strategy described in 1997,
A linear velocity of 3.84 (m / s) and a recording frequency of 26.16 (MHz) were applied to a DVD substrate (track pitch 0.8 μm) / an optical information recording medium mainly composed of a porphyrazine-based dye / gold reflective layer. ) To increase the recording power to 11.0
(Mw) to 14.0 (mw).

As shown in FIG. 5, the recommended strategy is composed of a top pulse and a multi-pulse in each recording pulse (write pulse) of 4T (T is a clock cycle) to 14T. The pulse width is Tmp. The 3T recording pulse is only the top pulse. The pulse width Ttop of the top pulse is selected according to the length Twd of the recording data. Here, Ttop = 1.25 When Twd = 3T Ttop = 1.20 When Twd ≧ 4T Tmp = 0.66T.

An experiment for measuring the jitter and the difference SP between the 14T space (S) width S and the 14T mark (Pit) width P was performed. Recording / reproducing is performed by Pulstec Industrial Co., Ltd. DDU-1000 (wavelength 635 nm,
The time / interval analyzer TA320 manufactured by Yokogawa Electric Corporation was used for measurement of mark / space width and jitter.

The result is as shown in FIG.
The power at which the T mark is optimally recorded (the recording power (Wri at which the difference between the 14T space width and the 14T mark width is minimized)
tePower). The recording power at which short marks such as 3T and 4T are optimally recorded (the measured jitter includes the jitter (Jitter) of all marks from 3T to 14T). However, from the frequency of each mark, the jitter is dominated by marks such as 3T, 4T, etc.), and short marks are not recorded satisfactorily at the power at which 14T marks are optimally recorded (long marks are not satisfactorily recorded). The short mark has insufficient sensitivity at the recording power capable of recording.)

Therefore, based on this result, the recording power (11.5 (m
In w)), recording was performed by changing the pulse width of 3T.
The recording conditions at this time are the same as in the above experiment except for the 3T pulse width. The results are as shown in FIG. 7. When the jitter and the difference SP between the 14T space width S and the 14T mark width P were measured in the same manner as in the above-described experiment, the recording power of this optical information recording medium was 11.5 ( mw), recording strategy Ttop = 1.30 When Twd = 3T Ttop = 1.20 When Twd ≧ 4T Tmp = 0.66T, the 3T pulse width at which the 14T mark is optimally recorded and the 3T mark at which the short mark is optimally recorded are: It was found that good recording was performed in which the fields were substantially the same (that is, the power at which 14T was optimally recorded and the power at which the short marks were optimally recorded). In addition, it was found from this experiment that by repeating this operation easily, a finer optimal strategy was required.

[0039]

As described above, according to the first aspect of the present invention, a recording strategy and an optimum recording power suitable for each optical information recording medium can be easily obtained by the above configuration.

According to the second aspect of the present invention, a recording strategy and an optimum recording power suitable for each optical information recording medium can be easily obtained by the above configuration.

According to the third aspect of the present invention, a recording strategy and an optimum recording power suitable for each optical information recording medium can be easily obtained with the above configuration.

According to the fourth aspect of the present invention, a recording strategy and an optimum recording power suitable for each optical information recording medium can be easily obtained by the above configuration.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a recording strategy evaluation method according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an optimal strategy evaluation device of the embodiment.

FIG. 3 is a flowchart illustrating a recording strategy evaluation method according to another embodiment of the present invention.

FIG. 4 is a block diagram showing an optimal strategy evaluation device of the embodiment.

FIG. 5 is a diagram illustrating a recording strategy according to the embodiment.

FIG. 6 is a characteristic diagram showing experimental results of the example of the present invention.

FIG. 7 is a characteristic diagram showing another experimental result of the example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording strategy determination means 2 Modulator 3 Optical pickup 4 Optimal recording power determination means by longest mark 5 Jitter minimum recording power determination means 6 Recording strategy determination means 7 Strategy adjustment means 8 Optical information recording medium 11 Recording strategy determination means 12 By longest mark Optimal recording power determining means 13 Shortest mark strategy adjusting means 14 Optimal recording power determining means based on longest mark 15 Recording strategy determining means

Claims (4)

[Claims] A recording method for recording marks on an optical information recording medium using different recording strategies for at least a shortest mark and other marks, wherein the jitter includes all recording marks or only the shortest recording mark. A recording strategy evaluation method, wherein a recording strategy is selected such that a recording power at which a jitter is minimized and a recording power at which a deviation of a longest recording mark from a theoretical value are minimized are substantially equal. 2. A recording method for recording a mark on an optical information recording medium using a recording strategy, wherein the recording power is changed by using a recording strategy set arbitrarily. The amount of deviation of the longest recording mark from the theoretical mark length was measured, and the recording power that minimized this deviation was determined. The recording power of the short mark is continuously changed with the recording power determined in step 2, jitter including all recording marks,
Alternatively, an optimal strategy for a short mark that minimizes the jitter of only the shortest recording mark is determined, and Using the recording strategy determined in step (1), the recording power was changed to measure the amount of deviation of the longest recording mark from the theoretical mark length, and the recording power that minimized this deviation was determined. Until the recording power obtained in step 4 becomes substantially equal to the recording power obtained in step 4, and finally determine a recording strategy in which the recording power obtained in step 4 is substantially equal to the recording power obtained in step 4 as an optimum recording strategy. A method for determining an optimum recording strategy. 3. An optical information recording apparatus for recording marks on an optical information recording medium using different recording strategies for at least a shortest mark and other marks, wherein the jitter includes all recording marks or the shortest recording mark. An optimum recording strategy characterized by comprising means for searching for a recording strategy such that the recording power at which the jitter of only the recording mark becomes minimum and the recording power at which the deviation from the theoretical value of the longest recording mark become minimum are substantially equal. Evaluation device. 4. An optical information recording apparatus for recording a mark on an optical information recording medium by using a recording strategy, wherein a recording power is changed by using an arbitrarily set recording strategy and a deviation of a longest recording mark from a theoretical mark length. The first means for measuring the recording power and the recording power at which the deviation amount is minimized, and the recording strategy for the short mark is continuously changed by the recording power obtained by the first means, and all the recording marks are recorded. A second means for determining an optimum strategy for a short mark in which the included jitter or the jitter of only the shortest recording mark is minimized, and a recording strategy obtained by the second means,
A third means for measuring a deviation amount of the longest recording mark from the theoretical mark length by changing the recording power and obtaining a recording power which minimizes the deviation amount, and a recording power obtained by the first means. The first to third means are repeatedly operated until the recording power obtained by the third means becomes substantially equal, and the recording power obtained by the first means and the recording power obtained by the third means are obtained. A fourth means for finally determining a recording strategy having substantially the same recording power as an optimal recording strategy.