JP2006012222A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device which allows power adjustment by the degree of modulation to be properly performed by easily and smoothly detecting a space level (Is) without using a peak holding circuit or the like. <P>SOLUTION: When recording is performed by a recording laser power Pp, a reproduced RF signal inputted from a signal amplification circuit is monitored, and a signal level Im of a mark area and a signal level Ib of a space area are acquired on the basis of a sampling and holding (S/H) signal. Is=Ib×(Pp/Pb) is calculated on the basis of the acquired signal level Im, the recording laser power set value Pp in the mark area, and a reference laser power set value Pb in the space area, and a signal level Is corresponding to the intensity of reflected light just after the rise of recording power is acquired. The degree of modulation M(M=(Is-Im)/Is) is calculated by signal levels Is and Im, and the laser power is so adjusted that the degree of modulation M becomes a target value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an optical disk apparatus that records and / or reproduces information using laser light, and is particularly suitable for use in adjusting laser power.

  Currently, various optical recording media such as CD (Compact Disc) and DVD (Digital Versatile Disc) have been commercialized and are widely used. Among these recording media, write-once media such as CD-R and DVD-R use an organic dye as a recording layer material, so that the reflectance of the recording layer changes according to the change in wavelength. That is, these media have wavelength dependency in recording characteristics.

  On the other hand, the temperature of the semiconductor laser rises with time after lighting, and the wavelength of the emitted laser light shifts accordingly. For this reason, in a recording medium having wavelength dependency such as CD-R and DVD-R, it is necessary to dynamically change the recording power in accordance with the wavelength fluctuation after lighting. On the other hand, Patent Document 1 shown below describes a technique for dynamically changing a set value of recording power based on an RF signal being recorded.

  FIG. 7A schematically shows an RF signal detected during the recording operation. In the figure, laser light is irradiated to the recording layer at the reproduction power level in the space portion, and the laser power is raised to the recording power level in the mark portion. However, since the mark is not formed immediately after the rise of the recording power, the same reflected light amount (RF signal = Is) as that obtained when the laser light of the recording power level is irradiated onto the space portion can be obtained. Thereafter, when the mark starts to be formed with the temperature rise of the recording layer, the reflected light level (RF signal) falls accordingly, and gradually shifts to the reflected light level after the mark formation (RF signal = Im). .

Here, if the reflected light level (RF signal = Is) immediately after the rise of the recording power and the reflected light level (RF signal = Im) of the mark portion are known, the modulation degree (Is−Im) / Is of the reflected light intensity is calculated. In addition, the recording mark formation state can be monitored in real time during recording. Therefore, in Patent Document 1, the space level (Is) and the mark level (Im) are detected from the RF signal being recorded, and the recording laser power is adjusted based on the degree of modulation of the reflected light intensity.
Japanese Patent No. 3096239

  However, in the above adjustment method, since the generation period of the space level (Is) is extremely short, a special hardware configuration such as a peak hold circuit is separately required to detect this. On the other hand, if the laser power adjustment is performed only from the mark level (Im) without using the space level (Is), a special hardware configuration such as a peak hold circuit is not required, and the configuration can be simplified. . However, in this case, since the sensitivity of the recording layer fluctuates due to temperature changes, there arises a problem that stable laser power adjustment cannot be performed.

  FIG. 7A shows an RF signal in the case of a so-called high-to-low disk in which the reflectivity is reduced by mark formation, but the reflectivity is increased by mark formation. The RF signal in the case of a low-to-high disc has a waveform as shown in FIG. In this case, as shown in the figure, since the space level (Is) does not become a peak, even if a peak hold circuit or the like is used, the level cannot be detected accurately. Therefore, the space level (Is) is not detected by any method. As long as it is not possible to adjust the power by the degree of modulation.

Accordingly, an object of the present invention is to provide an optical disc apparatus that can easily and smoothly detect a space level (Is) without using a peak hold circuit or the like and thereby appropriately adjust power according to the degree of modulation. .

  In view of the above problems, the present invention has the following features.

  An optical disc apparatus according to a first aspect of the present invention comprises laser power setting means for setting a recording laser power and power adjustment means for adjusting a power setting value set by the laser power setting means. The adjusting means includes a first level obtaining means for obtaining a signal level Im corresponding to the amount of reflected disk light after the recording mark is formed when the mark section is scanned with the laser light having the recording power setting value Pp, and a space. Second level acquisition means for acquiring a signal level Ib corresponding to the amount of reflected light of the disk when the section is scanned with laser light having a reference power setting value Pb, and signal level Ib acquired by the second level acquisition means Based on the power setting values Pp and Pb, the recording mark is formed when the mark section is scanned with the laser beam having the power setting value Pp. Third level acquisition means for acquiring a signal level Is corresponding to the amount of disk reflection before being performed, and the power setting value based on the signal levels Im and Is acquired by the first and third level acquisition means Setting value adjusting means for adjusting Pp.

  According to a second aspect, in the optical disc apparatus according to the first aspect, the third level acquisition unit acquires the signal level Is by calculating Is = Ib × (Pp / Pb).

  According to a third aspect of the present invention, in the optical disc apparatus according to the first or second aspect, the set value adjusting unit obtains a modulation degree in the recording mark from the signal levels Im and Is, and calculates the obtained modulation degree and the target value. And the power setting value Pp is adjusted.

  According to a fourth aspect of the present invention, in the optical disc apparatus according to the third aspect of the invention, the set value adjusting means performs the first and second when the trial write is performed with the recording power set value set as the optimum value. The signal levels Im and Is are acquired by the third level acquisition means, the modulation degree at the time of the trial writing is obtained based on the acquired signal levels Im and Is, and the obtained modulation degree is set as the target value. .

  According to a fifth aspect of the present invention, in the optical disc apparatus according to the fourth aspect, the signal levels Im and Is obtained at the time of the trial writing and / or the modulation degree obtained based on these signal levels are used as target value data. The target value data is recorded on the optical disc, and the target value data is read from the disc and used as reference value data in the set value adjusting means during a recording operation.

  An optical disc apparatus according to a sixth aspect of the invention obtains a signal level Im corresponding to a disc reflection light amount after a recording mark is formed when a mark section is scanned with a laser beam having a recording power setting value Pp. Level acquisition means, second level acquisition means for acquiring a signal level Ib corresponding to the amount of reflected disk light when the space section is scanned with laser light having a predetermined power setting value Pb, and the second level acquisition means Based on the signal level Ib and the power setting values Pp and Pb acquired in this manner, a signal corresponding to the amount of reflected disk light before the recording mark is formed when the mark section is scanned with the laser beam having the power setting value Pp. Third level acquisition means for acquiring the level Is, and when the test writing is performed with the recording power setting value set as the optimum value, the first, second and second The signal levels Im and Is are acquired by the third level acquisition means, and the acquired signal levels Im and Is, and / or the modulation degree at the time of the trial writing obtained based on these signal levels Im and Is, It is recorded on the disc.

According to a seventh aspect, in the optical disc apparatus according to the sixth aspect, the third level acquisition means acquires the signal level Is by calculating Is = Ib × (Pp / Pb). And

  According to the present invention, the signal level Is is obtained based on the signal level Ib acquired by the second level acquisition means, the recording power setting value Pp, and the reference power setting value Pb. The signal level Is can be acquired without using a special hardware configuration, and the signal level Is can be obtained even when the signal level Is is not a peak value as in the case of a low-to-high disk. Can be obtained smoothly. Therefore, according to the present invention, laser power adjustment can be performed easily and appropriately while using the signal levels Is and Im.

  As in the sixth and seventh inventions, the signal levels Is, Im, and / or the modulation degree obtained based on these values when trial writing is performed with the optimum laser power are recorded on the disc. If this is the case, it is not necessary to perform trial writing again each time recording is performed or when a disc is mounted on a different device, thereby simplifying the process and suppressing waste of the recording area due to trial writing. Can do.

In addition, the characteristics and significance of the present invention will be further clarified by the following description of embodiments. However, the following embodiment is one exemplary embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to the following embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, FIG. 1 shows a configuration of a disc (DVD + R) according to the embodiment. As illustrated, the disk 100 is divided into an inner drive area, a lead-in area, a data area, a lead-out area, and an outer drive area in the radial direction. In addition, the inner drive area and outer drive area are divided into various zones. Of these, the laser power initial setting (OPC: Optimum Write Power Control) is performed using the inner disk test zone and outer disk test zone. Is called.

  Further, a spiral groove is formed on the disk 100 from the inner periphery toward the outer periphery, and data is recorded on the groove. Here, the groove meanders (wobbles) in the radial direction, and address information is held by the wobble. That is, a phase modulation section called ADIP (Address in pre-groove) is inserted in a monotonous meandering section at a constant period, and when the beam scans the phase modulation section, the change in reflected light intensity causes Address information is read and played back. The ADIP in the lead-in area records various control data for the disc by phase modulation, and includes identification information (manufacturer ID) of the disc manufacturer that produced the disc. ing.

  FIG. 2 shows a configuration of the optical disc apparatus according to the embodiment.

  As shown in the figure, the optical disk apparatus includes an ECC encoder 101, a modulation circuit 102, a laser drive circuit 103, a laser power adjustment circuit 104, an optical pickup 105, a signal amplification circuit 106, a demodulation circuit 107, and an ECC decoder 108. And a servo circuit 109, an ADIP reproducing circuit 110, a controller 111, and a temperature sensor 112.

  The ECC encoder 101 adds an error correction code to the input recording data and outputs it to the modulation circuit 102. The modulation circuit 102 performs predetermined modulation on the input recording data, further generates a recording signal, and outputs the recording signal to the laser driving circuit 103. The laser drive circuit 103 outputs a drive signal corresponding to the recording signal from the modulation circuit 102 during recording to the semiconductor laser 105a, and outputs a drive signal for emitting laser light having a constant intensity to the semiconductor laser 105a during reproduction. Here, the laser power is set to the laser power adjusted and set by the laser power adjustment circuit 104.

  The laser power adjustment circuit 104 initializes the laser power during recording and reproduction, adjusts the set laser power as appropriate according to the adjustment value supplied from the controller 111, and supplies this to the laser drive circuit 103. . Here, the initial setting of the laser power is performed, for example, according to the β method. That is, the β value (βtarget) of the disk is acquired from the controller 111, and the recording laser power for the disk is set to the optimum power based on the acquired βtarget. Details of the setting process will be described later.

  The optical pickup 105 includes a semiconductor laser 105a and a photodetector 105b, and writes / reads data to / from the disk by converging the laser light on the groove. In addition, the optical pickup 105, in addition to the objective lens actuator for adjusting the irradiation state of the laser beam to the groove, guides the laser beam emitted from the semiconductor laser 105a to the objective lens, and reflects the light reflected from the disk 100. Is provided with an optical system or the like for guiding the light to the photodetector 105b.

  The signal amplifying circuit 106 amplifies and arithmetically processes the signal received from the photodetector 105b to generate various signals and outputs them to the corresponding circuit. The demodulation circuit 107 demodulates the reproduction RF signal input from the signal amplification circuit 106 to generate reproduction data, and outputs the reproduction data to the ECC decoder 108. The ECC decoder 108 performs error correction on the reproduction data input from the demodulation circuit 107 and outputs it to the subsequent circuit.

  The servo circuit 109 generates a focus servo signal and a tracking servo signal from the focus error signal and tracking error signal input from the signal amplification circuit 106 and outputs them to the objective lens actuator of the optical pickup 105. Also, a motor servo signal is generated from the wobble signal input from the signal amplifier circuit 106 and output to the disk drive motor.

  The ADIP reproduction circuit 110 reproduces address information and various control information from the wobble signal input from the signal amplification circuit 106 and outputs them to the controller 111.

  The controller 111 stores various data in the built-in memory and controls each unit according to a preset program. The controller 111 holds a β value table in which the manufacture ID and the target β value (β target) are associated with each other. The controller 111 compares the manufacture ID acquired from the lead-in area (ADIP) of the disc with the β value table, reads the corresponding β target, and outputs it to the laser power adjustment circuit 104. Based on this, the laser power adjustment circuit 104 performs initial setting of the recording laser power.

  The temperature sensor 112 detects the temperature in the drive and outputs the detection result to the controller 111. The temperature sensor 112 is preferably arranged so as to detect the temperature near the recording position of the optical disk.

  Next, the laser power initial setting operation (OPC) in the laser power adjustment circuit 104 will be described.

First, FIG. 3 shows a β value calculation method. As shown in the figure, the β value is calculated based on the asymmetry of the reproduction signal. That is, the β value is determined from the asymmetry amplitude values A1 and A2 and the offset value OS.
β = {(A1−OS) − (A2 + OS)} / {(A1−OS) + (A2 + OS)} (1)
It is obtained by calculating.

  FIG. 4 shows an initial setting method (OPC) of the recording laser power Pp. As shown in the figure, the recording laser power Pp was recorded by reproducing the test data in either the inner disc test zone or the outer disc test zone with two kinds of laser power (Pw1, Pw2) determined in advance. Is obtained based on the β value (β1, β2). That is, a linear straight line is obtained from the β values (β1, β2), the intersection of this linear straight line and the β target of the disc supplied from the controller 111 is obtained, and the laser power corresponding to the obtained intersection is recorded on the disc. Temporarily determined as the laser power Pp.

  Thereafter, the test data is recorded again in either the inner disk test zone or the outer disk test zone with the temporarily set recording laser power Pp, and temporarily set based on the error rate when this is reproduced. The suitability of the recorded recording laser power is verified. If the error rate is equal to or less than a predetermined threshold, the temporarily set recording laser power Pp is set as the optimum laser power. If the error rate exceeds the threshold, the laser power setting process shown in FIG. 4 is performed. repeat.

  Note that the controller 111 also performs acquisition processing of the signal levels Is and Im for the reproduction RF signal at the time of the initial setting. Details of this processing will be described with reference to FIG.

  When performing trial writing with the temporarily set recording laser power Pp as described above, the controller 111 monitors the reproduction RF signal input from the signal amplification circuit 106 and based on the sample hold (S / H) signal. In addition, the signal level Im of the mark area and the signal level Ib of the space area are acquired. Based on the acquired signal level Im, the recording laser power setting value Pp in the mark area, and the reference laser power setting value Pb in the space area, Is = Ib × (Pp / Pb) is calculated, and the rise of the recording power is calculated. The signal level Is corresponding to the reflected light intensity immediately after is acquired.

  The controller 111 records the acquired signal levels Is and Im in the control area of the disc in response to the temporarily set recording laser power Pp being set as the optimum laser power based on the error rate as described above. . The recorded signal levels Is and Im are used when adjusting the recording laser power Pp during the recording operation, as will be described later.

  The modulation level M (M = (Is−Im) / Is) may be further calculated from these signal levels Is and Im, and this may be recorded together in the control area. Alternatively, the modulation degree M may be recorded in the control area instead of the signal levels Is and Im.

  In addition, in this embodiment, the temperature detected by the temperature sensor 112 at the time of trial writing and the identification information (set number, etc.) for identifying the optical disc apparatus are recorded together in the control area.

  Next, an adjustment operation (R-OPC) for adjusting the recording laser power Pp initially set by the OPC during the recording operation will be described.

  FIG. 5 shows a processing flow of such adjustment operation.

  When there is a request to start a recording operation (S101), the controller 111 first determines whether the recording operation is performed for the first time after the disk is replaced (S102). If this determination is Yes, it is next determined whether or not the identification information (set number, etc.) read from the control area of the disc matches its own identification information (S103).

  Here, it is assumed that the information recorded in the control area is read from the disk when the disk is loaded and stored in the built-in memory of the controller 111 prior to the start of the recording operation. If no identification information has been recorded in the control area of the disc such as an unrecorded disc, the determination in S103 is Yes.

  If the determination in S103 is Yes, the controller 111 executes the OPC operation as described above and sets the recording laser power Pp (S104). At the same time, during the OPC test writing, the signal levels Is and Im are acquired as described above, and the modulation degree Mo (Mo = (Is−Im) / Is) is calculated from the acquired signal levels Is and Im. (S105). Then, the recording laser power Pp, the signal levels Is, Im, the modulation degree Mo, the temperature To detected by the temperature sensor 112 at the time of the OPC, and its own identification information (set number, etc.) are stored in the control area of the disc. Recording is performed (S106). Note that the recording laser power Pp, the signal levels Is, Im, and the modulation degree Mo acquired in S104 and S105 are set as parameters used during the recording operation.

  On the other hand, when it is determined in S102 that the recording operation is not performed for the first time after the disk replacement (S102: N), or the recording operation is performed for the first time after the disk replacement, but in S103. When it is determined that the identification information (set number, etc.) read from the control area of the disc matches its own identification information (S103: N), the controller 111 determines the current temperature Tc as the temperature sensor 112. The difference ΔT between the current temperature Tc and the temperature To acquired from the control area of the disc is calculated (S111). Then, it is determined whether or not the temperature difference ΔT is smaller than the threshold temperature difference Ts (S112). If it is smaller, the recording laser power Pp, signal levels Is, Im, and modulation degree Mo acquired from the control area of the disk are determined. It is set as a parameter used during the recording operation (S113). If the temperature difference ΔT is equal to or greater than the threshold temperature difference Ts, the process proceeds to S104, and the setting of the recording laser power Pp by OPC, acquisition of the signal levels Is, Im, the modulation degree Mo, and the like and the recording process are executed.

  Thereafter, the controller 111 causes the optical pickup 105 to access the recording position, and sequentially records the recording data with the recording laser power Pp (S107).

  When the adjustment timing of the recording laser power Pp arrives during the execution of the recording operation (S108: Y), the controller 111 uses the reproduction RF signal input from the signal amplification circuit 106 at that time as shown in FIG. The signal levels Is and Im are acquired (S109). Then, the modulation degree M (M = (Is−Im) / Is) is calculated from the acquired signal levels Is and Im, the calculated modulation degree M is compared with the modulation degree Mo acquired in S105 or S113, and the comparison result Accordingly, the recording laser power Pp is adjusted.

  Such adjustment is performed as follows, for example.

(1) If M = Mo, Pp = Pp
(2) If M <Mo, Pp = Pp + α
(3) If M> Mo, Pp = Pp-α
In addition, α may be increased or decreased according to the difference between the two modulation degrees.

  Note that the adjustment timing of the recording laser power Pp is, for example, the timing at which a fixed time elapses from the start of the recording operation. Alternatively, it may be a timing when the temperature T detected by the temperature sensor 112 changes by a predetermined temperature range or more with respect to the temperature at the previous recording laser power adjustment.

  As described above, according to the present embodiment, since the signal level Is is obtained based on the signal level Ib, the recording power setting value Pp, and the reference power setting value Pb, a special hardware configuration such as a peak hold circuit is provided. The signal level Is can be acquired without separately using. Thereby, the adjustment operation (R-OPC) of the recording laser power can be performed simply and appropriately.

  In addition, in the above embodiment, the recording laser power Pp, the signal levels Is, Im, the modulation degree Mo, the temperature To detected by the temperature sensor 112 during the OPC, and its own identification information (set number, etc.) If the difference ΔT between the temperature T at the time of R-OPC and the temperature To is within the threshold temperature Ts, the data stored in the control area is used as a reference for the recording operation. Since it is used as data, it is possible to avoid unnecessary OPC operations and operations for obtaining signal levels Is, Im and modulation degree Mo by trial writing. Accordingly, it is possible to reduce the waste of the test area (disk test zone) due to trial writing as well as simplifying the processing.

  In the present embodiment, an optical disk apparatus that records and reproduces data on a DVD + R disk is shown. However, the present invention can of course be applied to other optical disk apparatuses. In the next-generation DVD using blue laser light, a so-called Low-to-High disk whose reflectivity is increased by the formation of a recording mark has been studied, and an optical disk apparatus for recording / reproducing on such a disk. Even when the present invention is applied, the signal levels Is and Im can be acquired smoothly. Therefore, the recording laser power adjustment based on the modulation degree can be appropriately performed.

  FIG. 5B is a diagram showing the relationship between the RF signal and the S / H signal when recording is performed on such a low-to-high disc. Also in this case, the signal level Im of the mark area and the signal level Ib of the space area are obtained based on the sample hold (S / H) signal, and among these, the signal level Im and the recording laser power setting value in the mark area are obtained. Based on Pp and the reference laser power setting value Pb in the space area, Is = Ib × (Pp / Pb) is calculated to obtain the signal level Is corresponding to the reflected light intensity immediately after the rise of the recording power. Can do. Then, M = (Is−Im) / Is can be calculated from the calculated Is and the signal level Im of the mark area to obtain the modulation degree M. By adjusting the recording laser power based on the modulation degree M in the same manner as in the above embodiment, the recording laser power can be made to follow an appropriate value.

  In the flowchart of FIG. 6, when S112 is Yes, the recording laser power Pp acquired from the control area of the disc is set as the recording laser power at the time of the recording operation as it is (S113). The correction coefficient a may be set based on the magnitude of the temperature difference ΔT, and the recording laser power Pp acquired from the control area multiplied by the correction coefficient a may be set as the recording laser power during the recording operation. In this way, the recording laser power at the start of the recording operation can be set to a more appropriate value.

  For setting the correction coefficient a, a table in which the temperature difference ΔT and the correction coefficient a are associated with each other is prepared in the controller 111 in advance, and the correction coefficient a corresponding to the temperature difference ΔT is acquired with reference to this table. The method can be adopted. Alternatively, in the case of a DVD, the relationship between the temperature change and the wavelength shift of the laser beam is known (a shift of about 2 nm at 10 ° C.). From this and the general tendency of the wavelength characteristics of the recording layer, the temperature difference ΔT is The correction coefficient a may be approximated based on the original.

  In the above embodiment, if it is determined that the recording operation is not performed for the first time after the disk replacement (S102: N), or the recording operation is performed for the first time after the disk replacement, the process proceeds to S103. If it is determined that the identification information (set number, etc.) read from the control area of the disc and the identification information of the disc match (S103: N), the current temperature Tc and the control area of the disc are used. Only when the difference ΔT of the acquired temperature To is equal to or greater than the threshold temperature difference Ts, the acquisition operation of the signal levels Is, Im, modulation degree Mo, etc. by the OPC operation or trial writing is performed, but always at the start of the recording operation. The reference data acquisition operation by OPC operation or trial writing may be executed. In such a case, the recording in S106 (recording of laser power Pp, signal levels Is, Im, etc.) can be omitted. However, in this case, since the disc test zone is used by OPC or trial writing for each recording operation, there is a high possibility that the disc test zone will be used up before the data area is used up. .

In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

The figure which shows the structure of the optical disk which concerns on embodiment The figure which shows the structure of the optical disk apparatus which concerns on embodiment The figure explaining the calculation method of beta value concerning an embodiment The figure explaining the setting method of the laser power which concerns on embodiment The figure explaining the adjustment method of the laser power which concerns on embodiment Flowchart showing laser power adjustment processing according to the embodiment Diagram explaining the problems of the prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 103 Laser drive circuit 104 Laser power adjustment circuit 105 Optical pick-up 106 Signal amplification circuit 111 Controller

Claims (7)

A laser power setting means for setting a recording laser power; and a power adjustment means for adjusting a power setting value set by the laser power setting means,
The power adjusting means;
First level acquisition means for acquiring a signal level Im corresponding to the amount of reflected disk light after the recording mark is formed when the mark section is scanned with the laser beam having the recording power setting value Pp;
Second level acquisition means for acquiring a signal level Ib corresponding to the amount of reflected disk light when the space section is scanned with laser light having a reference power setting value Pb;
Based on the signal level Ib acquired by the second level acquisition means and the power setting values Pp and Pb, before the recording mark is formed when the mark section is scanned with the laser beam having the power setting value Pp. Third level acquisition means for acquiring a signal level Is corresponding to the amount of reflected light of the disk;
Setting value adjusting means for adjusting the power setting value Pp based on the signal levels Im and Is acquired by the first and third level acquiring means;
An optical disc device characterized by the above. In claim 1,
The third level acquisition means acquires the signal level Is by calculating Is = Ib × (Pp / Pb).
An optical disc device characterized by the above. In claim 1 or 2,
The set value adjusting means obtains a modulation degree at the recording mark from the signal levels Im and Is, compares the obtained modulation degree with a target value, and adjusts the power set value Pp.
An optical disc device characterized by the above. In claim 3,
The set value adjusting means acquires the signal levels Im and Is by the first, second and third level acquiring means when trial writing is performed with the recording power set value set as the optimum value. , Based on the acquired signal levels Im and Is, the degree of modulation at the time of trial writing is obtained, and the obtained degree of modulation is set as the target value.
An optical disc device characterized by the above. In claim 4,
The signal levels Im and Is acquired at the time of the trial writing and / or the modulation degree obtained based on these signal levels are recorded as target value data on the optical disc, and the target value data is recorded from the disc at the time of recording operation. Is used as reference value data in the set value adjusting means,
An optical disc device characterized by the above. First level acquisition means for acquiring a signal level Im corresponding to the amount of reflected disk light after the recording mark is formed when the mark section is scanned with the laser beam having the recording power setting value Pp;
Second level acquisition means for acquiring a signal level Ib corresponding to the amount of reflected disk light when the space section is scanned with laser light having a reference power setting value Pb;
Based on the signal level Ib acquired by the second level acquisition means and the power setting values Pp and Pb, before the recording mark is formed when the mark section is scanned with the laser beam having the power setting value Pp. Third level acquisition means for acquiring a signal level Is corresponding to the amount of reflected light of the disk,
When the trial writing is performed with the recording power setting value set as the optimum value, the signal levels Im and Is are acquired by the first, second and third level acquisition means, and the acquired signal level Im and Is and / or recording the degree of modulation at the time of the trial writing determined based on the signal levels Im and Is on the disc,
An optical disc device characterized by the above. In claim 6,
The third level acquisition means acquires the signal level Is by calculating Is = Ib × (Pp / Pb).
An optical disc device characterized by the above.

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