JP2003162817A - Optical storage medium recording method, optical storage medium recording apparatus, and optical storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical storage medium recording method, an optical storage medium recording apparatus, and an optical storage medium, capable of precisely recording/reproducing a recorded multi-valued data signal. <P>SOLUTION: A recording signal (test data, including all patterns) is generated (S2), and mark lengths or space lengths before and after the signal to be recorded are detected (S3). The timing for the laser irradiation corresponding to this is read out (S4), and the signal is recorded (S5). Then, the recorded signal is reproduced (S6), and the reproduced signal waveform is compared with an ideal signal waveform (S7). When the comparison result is equal to or more than a prearranged value (S8; N), the timing for the laser irradiation is corrected (S9), returning to the step 4. When the comparison result is not equal to or more than the prearranged value (S8; Y), the process is completed. Finally, the mark which is approximately equal to the ideal signal waveform in every pattern and which can precisely reproduce the multi-valued data is recorded. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method of an optical disc (optical storage medium) capable of recording information, an optical disc recording apparatus and an optical disc, and more particularly to an optical storage medium recording method and an optical storage medium recording by a multi-value recording system. The present invention relates to a device and an optical storage medium.

[0002]

2. Description of the Related Art As a technique for increasing the density of an optical disc, a technique for forming smaller pits and recording marks on the optical disc has been proposed. Since the wavelength of the light source of the recording / reproducing apparatus and the NA (numerical aperture) of its objective lens are limited, the size of the pits and recording marks that can be formed is limited by the wavelength of the light source of the recording / reproducing apparatus and the objective lens thereof. Determined by NA (numerical aperture). Recently, as a technique for further increasing the recording capacity without changing the NA of the light source and the objective lens of the recording / reproducing apparatus, an optical disc of a multi-valued recording system of three or more values is proposed instead of the conventional binary recording. , Has been announced.

This multi-valued recording system uses a phase change type optical disk and detects a signal level (amount of reflected light) corresponding to the size of a recording mark as one of multi-valued data.
The size of the recording mark is smaller than the reproduction light spot diameter,
The average reflected light amount including the target recording mark and the adjacent recording mark is detected as a signal. FIG. 11 is a diagram showing an RF signal, a recording mark, and a reproduction spot light of the multilevel recording system. In FIG. 11A, an RF signal of four-value recording is shown as an example. Figure 11
11A is a conceptual diagram of the recording mark and the reproduction spot light at the signal levels LV1 and LV3 of FIG.
This is shown in (b) and FIG. 11 (c). Since the recording mark is smaller than the reproduction spot diameter, even if there are four recording marks, they cannot be separated, and the reproduction signal becomes a stepwise signal as shown in FIG. In binary recording, information is detected as a mark position, whereas in multi-valued recording, it is detected as a mark reflectance. By combining this technology with signal processing, CD-RW
(Compact Disc-ReWritable)
3 times the capacity can be achieved.

By the way, in Japanese Patent Laid-Open No. 10-134353, in order to accurately reproduce multi-value recorded data,
After recording the test data on the optical disc master, by reproducing this, by correcting the laser irradiation conditions for forming pits that can be accurately reproduced from this reproduction result, by switching the pit depth of the optical disc in multiple stages, An optical recording device, an optical recording medium and an optical recording method for recording multi-valued data in each pit are described.

[0005]

However, in the above-mentioned optical disc, since the size of the recording mark is smaller than the reproducing light spot diameter, the difference in signal level between the marks becomes small and the data is accurately recorded. It is difficult to record and reproduce. Further, since the signal level varies depending on the size of the adjacent recording marks, erroneous detection of data is likely to occur. The erroneous detection of data will be described with reference to FIG. FIG. 12C is a diagram showing the relationship between the recording mark and the recording / reproducing light spot. The recording mark is formed in a cell having a fixed length, and the spot diameter of the recording / reproducing light is a size that extends over three cells.
Here, marks of level 3, level 1, and level 2 are recorded in order from the left cell. After that, the center of the recording / reproducing light spot having such a pattern is located at the center of the cell recording level 1, the level 3 is recorded in the preceding cell, and the level 2 is recorded in the subsequent cell. The pattern is {3, 1, 2}.

FIG. 12A shows four-value recording (level 0,
It is a figure showing the RF signal waveform of 1, 2, 3), and the vertical axis is standardized by the signal level of level 0. The signal level is captured at fixed time intervals Ts, and its timing is synchronized with the cell cycle. TL1 to TL3 are thresholds for detecting reproduced signals of levels 1 to 3. The problem here is that the level 1 signal level in the pattern {3, 1, 3} becomes smaller than the level 1 signal level in the pattern {0, 1, 0}. Therefore, the level 1 in the pattern {3, 1, 3} will be erroneously detected as the level 2 during reproduction. FIG. 12B is a diagram showing an RF signal level distribution when recording and reproducing all patterns. The distribution of each multilevel signal level has a range,
There is a portion where the distributions overlap (hatched portion). It is not possible to determine a multi-valued level for the signal level located in this shaded area. That is, it indicates that there is a possibility of misreading. In order to reproduce the multi-valued data accurately, it is necessary to narrow the width of this distribution and arrange the multi-valued levels so that they do not overlap.

Therefore, a first object of the present invention is to provide an optical storage medium recording method, an optical storage medium recording device and an optical storage medium which can accurately record and reproduce recorded multi-valued data signals. A second object of the present invention is to provide an optical storage medium recording method, an optical storage medium recording device, and an optical storage medium capable of recording a new mark while erasing an existing mark with one laser beam. . A third object of the present invention is to provide an optical storage medium recording method, an optical storage medium recording device, and an optical storage medium capable of forming a recording mark smaller than the recording laser spot diameter.

[0008]

According to a first aspect of the present invention, by irradiating an optically rewritable optical storage medium with a laser, multi-valued data which is multi-valued according to information to be recorded. In the optical recording medium recording method for recording a mark as a mark, when recording a mark on the optical storage medium, a first step of detecting a mark length before and after, and the mark before and after detected by the first step A second step of setting the timing of irradiating the optical storage medium with laser light according to the length, and recording a mark of multi-valued data by performing laser irradiation at the set timing. Achieve the first objective.

According to the second aspect of the invention, by irradiating an optically rewritable optical storage medium with a laser beam, multi-valued data which is multi-valued according to information to be recorded is recorded as a mark. In the storage medium recording method, when recording a mark on the optical storage medium, a first step of detecting a space length between a front and a rear mark and a front and rear space length detected by the first step are performed. And a second step of setting a timing of irradiating the optical storage medium with laser light and recording a mark of multi-valued data by performing laser irradiation at the set timing. Achieve the purpose.

According to a third aspect of the present invention, in the first or second aspect of the invention, multi-valued data is recorded in the optical storage medium by the second step and then recorded in the optical storage medium. A third step of reproducing multi-valued data and acquiring it as a reproduction result, and a fourth step of correcting the laser irradiation timing set in the second step based on the reproduction result acquired in the third step. The first object is achieved by the following steps. According to a fourth aspect of the present invention, in the third aspect of the invention, the correction of the laser irradiation timing in the fourth step is performed so as to minimize intersymbol interference, thereby achieving the first object. To achieve.

According to a fifth aspect of the present invention, by irradiating the optically rewritable optical storage medium with a laser, multi-valued data which is multi-valued according to the information to be recorded is recorded as a mark, In the optical storage medium recording method capable of reproducing the recorded marks, a first step of outputting a test signal to the optical storage medium in which the multi-valued data is recorded and detecting the mark length and space length before and after When,
A second step of setting the irradiation timing based on the front and rear mark lengths and the space length detected in the first step, and performing laser irradiation at the set timing; Is recorded as a threshold value, the third step of recording the timing of laser irradiation in the second step, and the optical storage based on the threshold value recorded in the third step. A fourth step of reproducing the multi-valued data recorded on the medium, and a fifth step of resetting the threshold value recorded in the third step based on the result reproduced by the fourth step. The first object is achieved by the following steps. In the invention according to claim 6, in the invention according to claim 5, the fourth
A step of dividing the recorded mark into a plurality of data recording units and reproducing a timing signal for reading a multilevel signal level at the head of the divided data recording unit when reproducing the multilevel data by the step Steps of
A seventh aspect of rotating the optical storage medium such that the timing signal recorded in the sixth step has a predetermined frequency.
The first object is achieved by the following steps.

In the invention according to claim 7, in the invention according to any one of claim 1, claim 2, claim 3, claim 4, claim 5, and claim 6, the second step A mark is recorded by switching the intensity of the laser irradiated in the first stage, the second stage, and the third stage, and the switching of the laser intensity is performed in the second stage higher than the first stage. It is said that the laser intensity is raised, and after the laser intensity is raised, the laser intensity is reduced to the third stage, which is lower than the first stage and the second stage, and the laser intensity is raised to the first stage again. The size of the recorded mark is determined by the switching timing of the intensity of the laser, thereby achieving the second object.

According to an eighth aspect of the present invention, by irradiating an optically rewritable optical storage medium with a laser beam, multi-valued data which is multi-valued according to information to be recorded is recorded as a mark. In a recording medium recording device, when recording a mark on the optical storage medium, a detecting unit that detects a space length between a front mark and a rear mark, and the optical disc according to the front and rear space lengths detected by the detecting unit. Recording means for recording a mark of multi-valued data by setting laser irradiation timing on the storage medium and performing laser irradiation at the set timing, and multi-valued data recorded on the optical storage medium by the recording means. After that, based on the reproduction result acquired by the acquisition unit that reproduces the multi-valued data recorded in the optical storage medium and acquires the reproduction result, and the acquisition unit, And correcting means for correcting the timing of the laser irradiation is set by the serial recording means, by having a, to achieve the first object. In the invention according to claim 9, by irradiating an optically rewritable optical storage medium with a laser, multi-valued data which is multi-valued according to information to be recorded is recorded as a mark, and the mark is recorded. In an optical storage medium recording device capable of reproducing marks, a detection means for outputting a test signal to the optical storage medium on which the multi-valued data is recorded to detect the mark length and the space length, and the detection means. Based on the mark length and the space length detected by, the irradiation timing is set, the irradiation means for performing laser irradiation at the set timing, and the threshold when the mark of the multi-valued data is recorded. As a value, based on the recording means for recording the timing of laser irradiation by the irradiation means and the threshold value recorded by the recording means, the optical recording is performed. Reproducing means for reproducing the multi-level data recorded on the medium,
The first object is achieved by including setting means for setting and adjusting the threshold value recorded by the recording means on the basis of the result reproduced by the reproducing means.

According to a tenth aspect of the invention, in the ninth aspect of the invention, when the multi-valued data is reproduced by the reproducing means, the recorded mark is divided into a plurality of data recording units, and the divided marks are divided. Signal recording means for recording a timing signal for reading a multilevel signal level at the head of the data recording unit, and rotating means for rotating the optical storage medium so that the timing signal recorded by the signal recording means has a predetermined frequency. And (1) are further provided, thereby achieving the first object.

According to an eleventh aspect of the present invention, by irradiating an optically rewritable optical storage medium with a laser, the multivalued data multivalued according to the information to be recorded can be obtained. Claim 2, claim 3, claim 4, claim 5,
7. An optical storage medium recorded as a mark by the optical storage medium recording method according to claim 6, wherein a test signal for correcting laser irradiation timing other than the mark area recorded on the optical storage medium. By providing the recording area for recording, the first object is achieved. According to a twelfth aspect of the present invention, in the eleventh aspect of the present invention, the recording area is recorded with a test signal serving as a reference for setting a threshold value for discriminating the multi-valued data. Achieve the purpose of.

According to a thirteenth invention, in the invention according to the eleventh or the twelfth invention, the storage area is
The first object is achieved by being divided into a plurality of data recording units and recording a timing signal serving as a reference for detecting the multi-valued data at the head of the data recording unit. In the invention according to claim 14, in the invention according to any one of claim 11, claim 12, and claim 13, the optical storage medium is a phase-change optical disk, and thus the third object To achieve.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described in detail below with reference to FIGS.
As described above, thermal interference at the time of mark recording can be considered as a cause of the signal level fluctuation. For example, when the recording marks immediately before or immediately after are large, heat at the time of recording those marks is transmitted, and the target mark may be formed larger than the designed value. Therefore, in the present embodiment, the multi-level signal data is accurately reproduced by setting the timing of laser irradiation in accordance with the adjacent mark length or the space length and recording in consideration of thermal interference due to the adjacent marks during recording. It is supposed to do.

FIG. 1 is a flow chart showing the flow until the recording parameters are set. First, a recording signal (including test data and all patterns) is generated (step 2), and the mark length or space length before and after the signal to be recorded is detected (step 3). Then, the laser irradiation timing corresponding to this is read (step 4) and the signal is recorded (step 5). Next, the recorded signal is reproduced (step 6), and the reproduced signal waveform and the ideal signal waveform are compared (step 7). If this comparison result is greater than or equal to the predetermined value (step 8; N), the laser irradiation timing is corrected (step 9), and step 4
Return to. If the comparison result is not equal to or more than the predetermined value (step 8; Y), the process ends. At the end, a mark capable of reproducing multi-valued data, which is almost equal to the ideal signal waveform, is recorded in every pattern. Here, the ideal signal waveform is a waveform in which each multi-valued data signal can be reliably discriminated regardless of the pattern.

FIG. 2 is a diagram showing a laser emission waveform for forming a recording mark. The optical disc is a rewritable phase change type optical disc, and the recording track is in a crystalline state. Further, a case will be described in which the reference time for recording is T and the recording data is 3T. The laser power is changed from P1 to P2 after τa with reference to the time t0 when the pulse of the recording data rises,
It changes from P2 to P3 after τb, and from P3 to P1 after τc. When such a laser is applied to the optical disc,
A recording mark is formed between τa and τc on the recording film,
The mark is erased by P1 after τc. The size of the recording mark depends on the timing of laser irradiation τa, τb, τ
It changes according to c. With this laser emission waveform, marks can be formed and erased at the same time, and the marks can be formed smaller than the recording laser spot diameter by setting respective timings. Where τ
a and τb are parameters relating to the front mark length (front space length), and τc is a parameter relating to the rear mark length (rear space length). Since the influence of heat varies depending on the length of the adjacent mark or the length of the adjacent space, it is possible to record a mark that gives a desired reproduction signal by correcting the laser irradiation timing accordingly.

FIG. 3 is a diagram showing the cell length and the mark length in the case of 4-level recording. Here, 1 cell length is 7T,
Marks of levels 1, 2, and 3 are set to 1, 3, and 5T, respectively, and spaces 3, 2, and 1T are arranged in front of and behind them.
FIG. 4 is a diagram showing a timing chart when recording the pattern {3, 1, 2}. When recording level 1, the front and rear mark lengths or front and rear space lengths are detected and the timing [τa31, τ] set as shown in FIG.
b31, τc21]. The method of correcting the laser irradiation timing first detects a pattern that deviates from the reference level. This can be detected, for example, by subtracting the ideal signal waveform from the reproduced signal waveform. If both the reproduced signal waveform and the ideal signal waveform match, the difference signal becomes zero, and the unmatched portion appears as a signal, which is detected. Τ if a pattern is lower than the ideal signal waveform
Increase a and τb, or shorten τc. On the contrary, when it is large, τa is shortened or τb and τc are lengthened. Correction is continued until the level of the difference signal falls below the default value. Figure 6
FIG. 6 is a diagram showing a laser irradiation timing correction area.
As an area for recording the above test data, the user
A laser irradiation timing correction area as shown in FIG. 6 is provided on the optical disc in an area other than the user area for recording, reproducing, and erasing data, for example, on the inner circumference side.

FIG. 7 is a block diagram showing the structure of the optical disk recording / reproducing apparatus. First, test data including all patterns is output from the modulation signal generator and input to the front and rear mark length discriminator (discriminator) to identify the mark length to be recorded and the mark lengths before and after it. To do. Next, the laser irradiation timing corresponding thereto is read from the laser irradiation timing table, and the recording waveform corresponding to the setting is output from the recording waveform generation circuit. This is input to a laser drive circuit, a laser beam is emitted from a semiconductor laser provided in the optical head, and is focused on the optical disc by the optical head to form a recording mark. During reproduction, the reflected light from the optical disc is taken into a light receiver provided in the optical head and converted into an electric signal. This electric signal is input to the comparator through the reproduction signal amplifier. Here, the reproduced signal is compared with the ideal signal waveform, and the discriminator detects an error. For a pattern having an error larger than a specified value, the laser irradiation timing is corrected and the timing table is rewritten. By repeating this until the error becomes equal to or smaller than the predetermined value, the optimum laser irradiation timing can be obtained.

Since there are individual differences between the optical disc and the recording / reproducing apparatus, it is not possible to uniquely set the threshold value of the multilevel signal level. Thresholds are set for each combination to reproduce the data correctly. First, data for threshold value calibration is stored in the recording / reproducing apparatus, this is recorded, and the threshold value of the multilevel signal level is set by using this reproduced signal. This allows
A threshold calibration area can be provided in an area other than the user area where the user records, reproduces, and erases data on the optical disc, and the threshold calibration data is recorded in this area (see FIG. 6). Further, in order to accurately reproduce multilevel data, the timing of capturing the multilevel signal level is important, and it is desirable to capture the signal when the center of the reproducing light spot coincides with the center of the cell. The user recording area is divided into a plurality of data recording units, a timing signal recording area is provided at the beginning of the data recording unit, and the timing signal is recorded there (see FIG. 8). After rotating the optical disc so that this timing signal has a predetermined frequency, by capturing the multilevel signal level,
It is possible to prevent a reading error due to a timing shift.

An optical disk recording apparatus for calibrating the slice level will be described with reference to FIG. First, after outputting a slice level calibration test signal from the modulation signal generator, a recording mark is formed through a recording waveform generating circuit. At the time of reproduction, the signal is input from the light receiver to the slice level generator through the reproduction signal amplifier. Here, the slice level of each multi-valued data is generated and input to the multi-valued data discriminator. Next, a recording device that reproduces a multilevel signal using the recorded timing signal will be described with reference to FIG.
First, after outputting the timing signal from the modulation signal generator, the timing signal is recorded through the recording waveform generating circuit. At the time of reproduction, the signal is input from the light receiver through the reproduction signal amplifier to the timing signal detection circuit. Here, a timing signal is extracted, a synchronization signal is generated by a synchronization signal generation circuit, and this is input to a spindle motor drive circuit to control the rotation speed of the optical disc.

The optical storage medium according to the present embodiment has a wavelength of 6
It is assumed that the optical disk is a phase change type optical disk capable of recording with a laser beam of 50 nm. The substrate has a diameter of 120 mm and a thickness of 0.6
The substrate is made of polycarbonate and has a groove formed by injection molding on the surface of the substrate. The groove is
The spiral is continuous from the inner circumference to the outer circumference with a width of about 0.35 μm, a depth of about 40 nm, and a track pitch of 0.74 μm. By sequentially laminating a dielectric film, a phase change recording film, a dielectric film, and a reflective film on this substrate,
A phase change type optical disc is manufactured (see FIG. 9). Data recording / reproduction is performed with a wavelength of 650 nm and an objective lens NA0.
Recording linear velocity of 3.5 m / s using 60 recording / reproducing devices
To record 8 values. Cell length is 0.56 μm (12T, T =
0.133 μs), and the laser power is recorded at P1 = 8 mW, P2 = 15 mW, and P3 = 0.1 mW, respectively. Conventionally, the total sum of deviations at each level after waveform equalization 6σsum (= 6Σσi, i = 0, 1, 2, ...
7) = 1.2, the sum of the deviations at each level after waveform equalization is 6σsum = 0.84 in the recording method of the present embodiment in which the adjacent mark length is taken into consideration. . As shown in FIG. 10, it can be seen that the multi-valued levels are distributed without overlapping and the recorded multi-valued data can be accurately reproduced.

[0025]

According to the first aspect of the invention, when a mark is recorded on the optical storage medium, the first step of detecting the mark lengths before and after the mark and the mark lengths of the mark before and after the mark detected by the first step are performed. Then, the second step of setting the timing of irradiating the optical storage medium with the laser and recording the mark of the multi-valued data by performing the laser irradiation at the set timing is performed. The obtained mark can be recorded, and multi-value recorded data can be reproduced accurately.

According to a second aspect of the present invention, when a mark is recorded on the optical storage medium, a first step of detecting a space length between the mark and a front and rear mark, and a front and rear space length detected by the first step. The second step of setting the timing of laser irradiation of the optical storage medium and recording the mark of multi-valued data by performing laser irradiation at the set timing. It is possible to record a mark that gives a level, and it is possible to accurately reproduce multi-value recorded data.

According to the third aspect of the invention, after recording the multi-valued data in the optical storage medium by the second step, the multi-valued data recorded in the optical storage medium is reproduced, and the reproduction result is obtained. And a fourth step of correcting the laser irradiation timing set in the second step based on the reproduction result obtained in the third step,
Therefore, it is possible to accurately reproduce multi-value recorded data.

In the invention of claim 4, the correction of the laser irradiation timing in the fourth step is performed so that the intersymbol interference is minimized, so that a mark capable of obtaining a desired multilevel signal level can be recorded. , It is possible to accurately reproduce multi-value recorded data.

According to a fifth aspect of the present invention, a test signal is output to an optical storage medium on which multi-valued data is recorded, and the mark length and the space length are detected by the first step and the first step. The second step of setting the irradiation timing based on the set mark length and the space length, and performing the laser irradiation at the set timing, and the second step as the threshold value when the mark of multi-valued data is recorded. The third step of recording the timing of laser irradiation by the step of, and the fourth step of reproducing the multivalued data recorded in the optical storage medium based on the threshold value recorded in the third step. And the fifth step of adjusting the threshold value recorded in the third step on the basis of the result reproduced in the fourth step. The data can be reproduced accurately.

According to the sixth aspect of the invention, when the multi-valued data is reproduced by the fourth step, the recorded mark is divided into a plurality of data recording units, and the multi-valued signal is added to the head of the divided data recording units. Since it comprises a sixth step of recording a timing signal for reading a level and a seventh step of rotating the optical storage medium so that the timing signal recorded in the sixth step has a predetermined frequency, The recorded data can be reproduced accurately.

In the invention according to claim 7, a mark is recorded by switching the intensity of the laser irradiated in the second step between the first step, the second step and the third step, and the laser intensity of the laser is changed. Switching is the second higher than the first stage
The laser intensity is increased to the first stage, the laser intensity is decreased to the third stage, which is lower than the first stage and the second stage, and then the laser intensity is increased to the first stage. Since the size of the recorded mark is determined by the switching timing of the laser intensity, the laser power at the time of recording can be recorded in the order of erase power, recording power, cooling power, and erase power. New marks can be recorded while erasing existing marks at the spot.

According to an eighth aspect of the present invention, when a mark is recorded on the optical storage medium, a detecting means for detecting a space length between the front and rear marks, and a front and rear space length detected by the detecting means, After setting the timing of irradiating the optical storage medium with laser light, recording means for recording the mark of multi-valued data by performing laser irradiation at the set timing, and after recording the multi-valued data on the optical storage medium by the recording means, Acquisition means for reproducing multi-valued data recorded in the optical storage medium and acquiring it as a reproduction result, and correction means for correcting the laser irradiation timing set by the recording means based on the reproduction result acquired by the acquisition means. Since it is provided, the signal level difference due to any multi-valued data pattern can be removed, and multi-valued data can be accurately reproduced.

According to a ninth aspect of the invention, detecting means for outputting a test signal to the optical storage medium on which multi-valued data is recorded to detect the mark length and the space length, and the mark length detected by the detecting means. The irradiation timing is set on the basis of the space length and the irradiation means for performing the laser irradiation at the set timing, and the timing at which the laser irradiation is performed by the irradiation means as the threshold when the mark of the multi-valued data is recorded. Recording means for recording, a reproducing means for reproducing the multi-valued data recorded on the optical storage medium based on the threshold value recorded by the recording means, and a recording means for recording based on the result reproduced by the reproducing means. Since the threshold value recorded by the means is set and the threshold value is adjusted,
It is possible to accurately reproduce multi-valued data regardless of individual differences between the optical disc and the optical disc recording device.

According to the tenth aspect of the invention, when the multi-valued data is reproduced by the reproducing means, the recorded mark is divided into a plurality of data recording units, and the multi-valued signal level is set at the head of the divided data recording units. Since it further includes signal recording means for recording a timing signal to be read and rotation means for rotating the optical storage medium so that the timing signal recorded by the signal recording means has a predetermined frequency, multi-valued data can be accurately reproduced. can do.

According to the eleventh aspect of the present invention, since the recording area for recording the test signal for correcting the laser irradiation timing is provided in addition to the mark area recorded on the optical storage medium, the user recording capacity can be reduced. However, it is possible to record a mark that can accurately reproduce multi-valued data.

According to the twelfth aspect of the invention, the recording area is
Since the test signal serving as the reference for setting the threshold value for discriminating the multi-valued data is recorded, the multi-valued data can be accurately reproduced regardless of the variation of the optical disc.

According to a thirteenth aspect of the present invention, the storage area is
Since it is divided into a plurality of data recording units and a timing signal serving as a reference for detecting multi-valued data is recorded at the head of the data recording unit, it is possible to reduce reading errors due to timing deviation.

In the fourteenth aspect of the present invention, since the optical storage medium is a phase change type optical disc, direct overwriting is possible and a mark smaller than the recording laser spot diameter can be formed.

[Brief description of drawings]

FIG. 1 is a flowchart showing a flow until a recording parameter is set.

FIG. 2 is a diagram showing a laser emission waveform for forming a recording mark.

FIG. 3 is a diagram showing a cell length and a mark length in the case of 4-level recording.

FIG. 4 is a diagram showing a timing chart when recording a pattern {3, 1, 2}.

FIG. 5 is a diagram showing a timing of irradiating a laser.

FIG. 6 is a diagram showing an area provided on an optical disc.

FIG. 7 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus.

FIG. 8 is a diagram showing a timing signal recording area for recording a timing signal.

FIG. 9 is a diagram showing a stack of phase change optical disks.

FIG. 10 is a diagram showing standardized RF signal levels.

FIG. 11 is a diagram showing an RF signal, a recording mark, and a reproduction spot light of a multilevel recording system.

FIG. 12 is a diagram showing erroneous detection of data.

[Explanation of symbols]

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5D090 AA01 BB05 CC01 EE03 FF12                       HH03 JJ12 KK03 KK05                 5D119 AA22 BA01 BB04 DA01 HA48                       HA59                 5D789 AA22 BA01 BB04 DA01 HA48                       HA59

Claims (14)

[Claims] 1. An optical storage medium recording method for recording multi-valued data, which is multi-valued according to information to be recorded, as a mark by irradiating an optically rewritable optical storage medium with a laser, When recording a mark on the optical storage medium, a laser irradiation is performed on the optical storage medium according to a first step of detecting a front and rear mark length and a front and rear mark length detected by the first step. And a second step of recording a mark of multilevel data by irradiating the laser at the set timing, and a second step of recording the mark of the multivalued data. 2. An optical storage medium recording method for recording multi-valued data, which is multi-valued according to information to be recorded, as a mark by irradiating an optically rewritable optical storage medium with a laser, When recording a mark on the optical storage medium, a first step of detecting a space length between a front and a rear mark, and the optical storage medium according to the front and rear space lengths detected by the first step A timing for irradiating the laser beam is set, and the laser irradiation is performed at the set timing to record a mark of multi-valued data.
An optical storage medium recording method, comprising: 3. A third step of recording multi-valued data on the optical storage medium by the second step, reproducing the multi-valued data recorded on the optical storage medium, and acquiring the reproduction result. The fourth step of correcting the laser irradiation timing set in the second step based on the reproduction result obtained in the third step. The optical recording medium recording method described. 4. The optical storage medium recording method according to claim 3, wherein the correction of the laser irradiation timing in the fourth step is performed so that intersymbol interference is minimized. 5. An optical rewritable optical storage medium is irradiated with a laser to record multi-valued data, which is multi-valued according to information to be recorded, as a mark, and reproduction of the recorded mark. In the optical storage medium recording method, it is possible to output a test signal to the optical storage medium in which the multi-valued data is recorded, and detect a mark length and a space length before and after, and the first step. A second step of setting the irradiation timing based on the mark length and the space length detected in step and performing laser irradiation at the set timing; and when the mark of the multi-valued data is recorded. As a threshold value of, the third step of recording the timing of laser irradiation in the second step, and the recording of the timing in the third step. Based on the have value,
A fourth step of reproducing the multi-valued data recorded in the optical storage medium, and a setting step for setting the threshold value recorded in the third step based on the result reproduced by the fourth step. An optical storage medium recording method comprising a fifth step of correcting. 6. When reproducing the multi-valued data in the fourth step, the recorded mark is divided into a plurality of data recording units, and a multi-valued signal level is added to the head of the divided data recording units. A sixth step of recording a timing signal to be read, and a seventh step of rotating the optical storage medium such that the timing signal recorded in the sixth step has a predetermined frequency.
6. The optical storage medium recording method according to claim 5, further comprising: 7. A mark is recorded by switching the intensity of the laser irradiated in the second step between a first step, a second step and a third step, and the switching of the laser intensity is performed by The laser intensity is raised to the second stage, which is higher than the first stage, and after the rise, the laser intensity is reduced to the third stage, which is lower than the first stage and the second stage, and the first intensity is again set. 3. The steps of raising the laser intensity in steps are performed, and the size of the recorded mark is determined by the switching timing of the laser intensity. The optical storage medium recording method according to any one of claim 3, claim 4, claim 5, and claim 6. 8. An optical storage medium recording device for recording, as marks, multi-valued data which is multi-valued according to information to be recorded by irradiating an optically rewritable optical storage medium with a laser, When recording a mark on the optical storage medium, the optical storage medium is laser-irradiated in accordance with a detection unit that detects a space length between the front and rear marks, and the front and rear space lengths detected by the detection unit. Recording means for setting timing and recording a mark of multi-valued data by performing laser irradiation at the set timing; and after recording multi-valued data in the optical storage medium by the recording means, the optical storage medium The multi-valued data recorded on the recording medium is reproduced and is acquired as a reproduction result, and the recording means sets the reproduction result acquired by the acquisition unit. Optical storage medium recording apparatus characterized by comprising a correction means for correcting the timing of the laser irradiation. 9. By irradiating an optically rewritable optical storage medium with a laser, multi-valued data which is multi-valued according to information to be recorded is recorded as a mark, and the recorded mark is reproduced. In the optical storage medium recording device capable of performing the above, a detection unit that outputs a test signal to the optical storage medium on which the multi-valued data is recorded, and detects a mark length and a space length before and after, is detected by the detection unit. Based on the mark length and the space length, the irradiation timing is set, and irradiation means for performing laser irradiation at the set timing, and as a threshold value when the mark of the multi-valued data is recorded, Recording means for recording the timing of laser irradiation by the irradiation means, and recording on the optical storage medium based on the threshold value recorded by the recording means. The reproducing means for reproducing the stored multi-valued data, and the setting means for setting the threshold value recorded by the recording means on the basis of the result reproduced by the reproducing means. Optical storage medium recording device. 10. The timing of dividing the recorded mark into a plurality of data recording units when reading the multi-valued data by the reproducing means, and reading a multi-valued signal level at the head of the divided data recording unit. The signal recording means for recording a signal, and a rotating means for rotating the optical storage medium so that the timing signal recorded by the signal recording means has a predetermined frequency, further comprising: The optical storage medium recording device described. 11. The multi-valued data, which is multi-valued according to information to be recorded, by irradiating an optically rewritable optical storage medium with a laser, the multi-valued data according to claim 1, claim 2, or claim 3. An optical storage medium recorded as a mark by the optical storage medium recording method according to any one of claims 4, 5, and 6, wherein a laser is provided in a region other than the mark region recorded on the optical storage medium. An optical storage medium having a recording area for recording a test signal for correcting irradiation timing. 12. The optical storage medium according to claim 11, wherein a test signal serving as a reference for setting a threshold value for discriminating the multi-valued data is recorded in the recording area. 13. The storage area is divided into a plurality of data recording units, and a timing signal serving as a reference for detecting the multi-valued data is recorded at the head of the data recording unit. The optical storage medium according to claim 11 or 12. 14. The optical storage medium according to claim 11, wherein the optical storage medium is a phase change type optical disc.