KR20070090746A - Method for controlling write power in optical recording and reproducing apparatus - Google Patents

Abstract

A method and an apparatus for calibrating recording power in an optical recording/reproducing apparatus is provided to overcome the individual difference of recording power sufficiently in the optical recording/reproducing apparatus. An apparatus for calibrating recording power calibrates the recording power of a laser diode by performing test writing with respect to a test writing area of an optical disc. The apparatus includes a calculation unit, the first order approximate equation forming unit, and the optimum recording power calculating unit. The calculating unit calculates the correlations corresponding to an n^th power equation of various kinds of recording power and modulation calculated from an RF(Radio Frequency) signal in each recording power. The first order approximate equation forming unit selects an n^th power value representing the most correlation from among the correlations corresponding to the n^th power equation, and forms the first order approximate equation based on the selected optimum n^th power value. The optimum recording power calculating unit calculates the optimum power based on the first order approximate equation.

Description

Method for controlling recording power in optical recording and reproducing apparatus {Method for controlling write power in optical recording and reproducing apparatus}

1 is a functional block diagram showing an embodiment of a recording power adjusting method in the optical recording and reproducing apparatus according to the present invention.

2 is an operation flowchart for determining an optimal n power value and kappa? For each optical disk in the present embodiment.

3 is an operation flowchart until the optimum recording power Pwo is set in the optical recording and reproducing apparatus according to the present embodiment.

4 is an operation flowchart until the optimum recording power Pwo is set in the optical recording and reproducing apparatus according to the present embodiment.

5 is an explanatory diagram for explaining the recording power Pw.

6 is a waveform diagram showing an example of an RF signal when the modulation (m) is obtained.

FIG. 7 is a graph example in the present embodiment when data is plotted in a graph in which the vertical axis is m * Pw ⁿ and the horizontal axis is Pw ⁿ .

8 is a graph example in which graphs are plotted with data when the DOW is executed to obtain the standard recording power Pws.

Fig. 9 is an example of data when actual measurement data of the optical recording / reproducing apparatus #A is collected by applying the present embodiment.

FIG. 10 is a calculation example showing a calculation result of a calculation item such as optimum recording power Pwo based on the data of FIG. 9.

FIG. 11 shows an example of data when actual measurement data of the optical recording / reproducing apparatus #B is collected by applying the present embodiment.

FIG. 12 is a calculation example showing a calculation result of a calculation item such as optimum recording power Pwo based on the data in FIG.

FIG. 13 is a graph example when the graph is plotted with data obtained when the n power value is 5 power in the present embodiment.

14 is another example of a graph obtained by graph plotting data when the n power value is 5 power in the present embodiment.

FIG. 15 is an explanatory diagram for demonstrating the effectiveness of this embodiment in which the relationship between the jitter value and the recording power is graphed in the optical recording / reproducing apparatus #A and the optical recording / reproducing apparatus #B.

FIG. 16 shows an example of data when data is collected under the same conditions in this embodiment with the source in the optical recording / reproducing apparatus # 1.

FIG. 17 is an explanatory diagram showing the effectiveness of the present embodiment by calculating the source in the range A and the range B and the P threshold Pthr in the present embodiment from the data shown in FIG. 16 and showing the difference ΔPthr. to be.

18 shows an example of data when data is collected under the same conditions in this embodiment with the source in the optical recording / reproducing apparatus # 2.

FIG. 19 is an explanatory diagram showing the effectiveness of this embodiment by calculating the source in the range A and the range B and the P threshold Pthr in the present embodiment from the data shown in FIG. 18 and showing the difference ΔPthr. to be.

20 is a graph showing an example when the obtained data is graph plotted in the prior art.

(Explanation of the sign)

One . . . Optical disc

2 . . . Optical disk device

3. . . Personal computer

200. . . Spindle motor

202. . . Optical pickup

206. . . Stepping motor

208. . . driver

210. . . Analog front end

212. . . The signal processing circuit

214. . . Encoder / Decoder

216. . . Buffer memory

218. . . Host interface

220. . . MPU

222. . . Flash memory

The present invention relates to an optical recording and reproducing apparatus, and more particularly, to a method of adjusting laser power in a rewritable optical recording and reproducing apparatus.

The spread of optical discs as a recording medium of digital information such as data, music or video is remarkable in recent years. As this type of optical disk, for example, a recordable optical disk such as CD-R, a rewritable optical disk such as CD-RW, or a shorter wavelength of a semiconductor laser as a laser light source, having a high numerical aperture (Numerical Aperture) A large capacity optical disk such as DVD ± R, DVD ± RW, DVD-RAM, etc. is known due to the reduction in spot diameter by the high NA objective lens and the adoption of a thin substrate.

In this type of optical disc, information is recorded by a laser diode. The optimum recording parameters differ from each other by the characteristics of the optical disc and the compatibility with the optical disc apparatus. In other words, even for the same type, the optimum recording power of the laser diode is different for each manufacturer and for each media. For this reason, in the optical recording / reproducing apparatus for recording and reproducing on the optical disk, test writing is performed in the test area so that the recording power of the laser diode is optimal according to the individual optical disks, and the recording power is adjusted from the results. The research is done to carry out.

Among these optical discs, in a rewritable optical disc such as CD-RW or DVD ± RW, it is common to find the optimum recording power of the laser diode using the adjustment method of the recording power by the value of ν ( ν method). For example, it is recommended to use the Linear Fit method for the DVD + RW specification. This linear fit method is m * from the modulation power (m) of the reproducible reflected light intensity when test writing is performed on the write powers (Pw) of several types of laser diodes set during test writing. Find Pw. Then, a linear first-order approximation is made from data obtained by plotting the value of the recording power Pw on the horizontal axis of the graph and the m * Pw value on the vertical axis, and the value Pthr and the light obtained therefrom. The optimal recording power Pwo is calculated using ? Target and?, Which are disc information.

In this way, the linear fit method assumes that a linear approximation formula holds for the relational property of the recording power Pw and m * Pw multiplied by this value and the modulation degree (m). Not bent and slightly bent. With such curvature, since the inclination of the first approximation straight line varies depending on the data to be used, the optimal recording power may not be constant, and in the worst case, the recording power may be selected that becomes impossible to reproduce.

Therefore, it was found that only about two or three m * Pw can be used to accurately perform straight line approximation, and an accurate recording power cannot be obtained without a significant number of test writes and m * Pw operations. If the test write is repeated many times, the processing burden during adjustment for optimizing the recording power increases, and the adjustment time becomes long.

For this reason, for example, Japanese Patent Laid-Open No. 2005-209287 discloses a prior art which can obtain an optimum recording power with relatively high accuracy even with a small number of test writes. That is, in this prior art, as shown in FIG. 20, instead of m * Pw, the m * Pw ² value obtained by multiplying the modulation degree m by the power of the recording power Pw is used, and this is made the vertical axis of the graph On the horizontal axis, the recording power Pw is kept as it is, and the recording power is optimized with relatively high accuracy even with a small number of test writes.

However, in the technique disclosed in Japanese Patent Laid-Open No. 2005-209287, the optimization of recording power can be stabilized rather than using the linear fit method as it is, but even in this conventional technique, individual differences and the like of the optical recording / reproducing apparatus cannot be sufficiently absorbed. It was found through experiments that there are cases.

An object of the present invention is to solve such a problem of the prior art, and to provide a recording power adjusting method in an optical recording / reproducing apparatus that can sufficiently absorb the recording power individual difference of the optical recording / reproducing apparatus.

SUMMARY OF THE INVENTION In order to solve the above problems, the invention described in claim 1 is a recording power adjusting method in an optical recording / reproducing apparatus which adjusts the recording power of a laser diode by performing a test writing to a test writing area of an optical disk. N power of the modulation (m) and the recording power (Pw) from the modulation (m) calculated from the various types of recording power (Pw) set at the time of test writing and the RF signal at each recording power (Pw). multiplication value (m * Pw ⁿ⁾ and, from the relation of Pw ⁿ w n (n≥2) of the recording power, the recording in the optical recording and reproducing apparatus, characterized in that to create the primary approximate expression of ≥2) How to adjust the power.

In the invention according to claim 2, in the recording power adjustment method according to claim 1, the n-th power value having the strongest correlation is selected from the correlations of the n-th power expressions calculated, and a first approximation equation is made by the selected n-th power value. The optimum recording power Pwo is calculated from the first approximation formula thus created.

In the invention according to claim 3, in the recording power adjustment method according to claim 2, when the P threshold Pthr required for calculating the optimal recording power Pwo is set to the first approximation straight line y = ax + b, It is characterized by calculating in Pthr =-(b / a) ^{(1 / n)} .

The invention according to claim 4, in the recording power adjustment method according to claim 2, the optimum recording power Pwo is calculated by multiplying the P threshold Pthr obtained from the selected n power value and the coefficient kappa obtained for each optical disk. Characterized in that.

The invention as set forth in claim 5 is an optical recording and reproducing apparatus for adjusting a recording power of a laser diode by performing a test writing to a test writing area of an optical disk, comprising: a plurality of types of recording power Pw set at test writing; Calculation means for calculating the correlation of each nth expression from the modulation m calculated from the RF signals at the respective recording powers Pw, and n having the strongest correlation among the correlations of the nth expressions calculated by the calculation means. The optimal recording power Pwo is calculated from a first approximation formula generating means for selecting a multiplier value and creating a first approximation equation based on the selected optimal n power value and a first approximation formula created with the first approximation formula creation means. And an optimum recording power calculating means.

Hereinafter, with reference to the accompanying drawings, an embodiment of a recording power adjusting method in the optical recording and reproducing apparatus according to the present invention will be described in detail.

Referring to Fig. 1, there is shown a functional block diagram of the optical recording and reproducing apparatus according to the present invention. The optical disc 1 is a recording medium capable of recording, reproducing and erasing information (RW and RAM only) by a semiconductor laser, for example, CD-R, CD-RW, DVD ± R, DVD ± RW. , DVD-RAM, and the like.

The spindle motor 200 is a motor for rotating the optical disk 1, and rotates the linear speed constant or the angular speed constant. The spindle motor 200 is controlled by the driver 208 such as the rotation speed.

The optical pickup device 202 is a device for irradiating laser light onto the recording surface of the optical disk 1 on which the track is formed and receiving light reflected from the recording surface. The optical pickup device 202 includes a laser diode, a collimated lens, a beam splitter, an objective lens, a detection lens, a light receiver, and a drive system such as a focus actuator and a tracking actuator.

The stepping motor 206 is a motor that drives the slider 207 to move the optical pickup device 202 in the track direction. The stepping motor 206 is drive controlled by the driver 208 like the spindle motor 200.

The analog front end 210 is a signal processing circuit for shaping a detection signal from the optical pickup device 202 into a digital signal. The detection signal itself from the optical pickup device 202 is analog and the level to be detected is also very low and unstable. For this reason, the threshold for amplifying or equipping the analog front end 210 or for correcting it with a smooth square wave is always adjusted. The analog front end 210 also notifies the MPU 220 of the level when it receives the reflected light amount from the optical disk 1 being recorded than the optical pickup device 202.

The digital signal processing circuit 212 generates an RF signal indicating the total amount of reflected light to each area of the photo detector, and simultaneously outputs a focus error signal which is a signal for detecting a focus shift of the irradiation laser of the optical pickup device 202. It generates by the astigmatism method and further generates a tracking error signal which is a signal which detects the track shift of the irradiation laser of the optical pickup device 202 by the push-pull method. Also, a focus driving signal and a tracking driving signal are generated based on the generated focus error signal and tracking error signal, and output to the driver 208.

Further, when the digital signal processing circuit 212 receives a control command of the spindle motor 200, the optical pickup device 202, or the stepping motor 206 from the MPU 220, the digital signal processing circuit 212 outputs the control command to the driver 208. When the driver 208 inputs these error signals or control commands, the driver 208 performs drive control of the spindle motor 200, the optical pickup device 202, and the stepping motor 206.

The encoder / decoder 214 encodes the information recorded on the optical disc 1 sent from the personal computer 3, outputs it to the digital signal processing circuit 212, and at the same time, the optical disc 1 This is a circuit that decodes the information read from and sends it to the personal computer 3.

The buffer memory 216 is a memory that temporarily stores information exchanged with the personal computer 3. The host interface 218 is an interface for making a connection at the physical level and the signal level with the personal computer 3.

The MPU 220 is a main CPU that controls the entire optical disk device in accordance with programs and data (firmware) stored in the flash memory 222. In the present embodiment, the MPU 220 performs test writing on the test writing area of the optical disk in addition to the control of the normal optical disk device, and adjusts the recording power Pw in the laser diode of the optical pickup device 202. Equipped with. Specifically, it is provided with the calculation function which calculates the correlation coefficient of each n-th power form from the various types of recording power set at the time of test writing, and the modulation m calculated from the RF signal in each recording power, and a correlation coefficient. The first approximation equation is prepared by using the n-th power value (the n-th power value with the strongest correlation) among the correlations, thereby calculating the optimal recording power. The MPU 220 also has a function of calculating correlation coefficients and P thresholds Pthr.

As described above, the flash memory 222 is a memory in which programs and data necessary for the operation of the MPU 220 are stored. The flash memory 222 also temporarily stores data used for calculating the optimal recording power, correlation coefficient, kappa, and the like. The flash memory 222 also stores data related to the write strategy, write power Pws set by the write strategy designer, and the like.

2 to 4 are production process diagrams showing an embodiment of a recording power adjusting method in the optical recording and reproducing apparatus according to the present invention. The operation in this embodiment will be described below using these drawings.

2 is an operational flowchart for a strategy designer to determine the optimal n power value and kappa κ for each optical disk. Initially, start and end points of the recording power of the laser diode are set. This sets the + 15% to -45% as the start point and the end point with respect to the write power Ps set by the write strategy designer (step S100). In addition, in this specification, the recording power Pw means the power of the peak Pw of the pulse shown in FIG.

Subsequently, the start point and the end point set in step S100 are divided based on 18 steps, and the interval of the recording power Pw is set (step S102). A test write is performed in the OPC area at the recording power Pw of the interval set in step S102, and the modulation (m) is calculated by reading the RF signal (step S104). 6 shows waveforms of an RF signal for explaining the calculation of modulation (m). In FIG. 6, if the strongest RF signal is I 14H and the weakest RF signal is I 14L from the zero level, which is the reference level, modulation (m) is

    m = (I 14H-I 14L) / I 14H.

When the modulation m is calculated, the correlation coefficient is calculated next (step S106). After the modulation (m) is calculated, data having a vertical axis of m * PWn and a horizontal axis of PWn and satisfying 0.2≤m with the recording power of 18 steps set in step S102 is shown in FIG. 7 from the lower limit data. The graph is plotted as described above to find the first-order approximation straight line y = ax + b which is a regression approximation straight line. Perform this graph plot, for example, from powers 2 to 10, and calculate the correlation coefficients for each.

A and b and the correlation coefficient of the first order approximation straight line are obtained by the following equation.

If the first approximation straight line is y = ax + b,

Obtained from

From this, the correlation coefficient is computed by the following formula.

Correlation coefficient

When the correlation coefficient of the 2nd to 10th power is calculated in step S106, the n power value of the correlation coefficient which becomes the maximum is selected from this (step S108). If the n-th power value of the correlation coefficient, which is maximized by the step S108, is selected, the P threshold Pthr is calculated (step S110). Specifically, since the slope a and the piece b of y = ax + b are obtained by the above formula, the P threshold Pthr is thus obtained.

Pthr =-(b / a) ^{(1 / n)}

(N is the selected n power).

If P Threshold Pthr is obtained in step S110, kappa κ is obtained by using this value and the standard power Pws. The formula for kappa (κ) is

κ = Pws / Pthr

Becomes Here, the standard power Pws is determined by evaluating the DOW (Direct 0ver Write) characteristic shown in FIG. 8 in advance. In FIG. 8, for ease of understanding, the error rate specification is assumed to be 280 (linear Ll), and DOW (0), DOW (1), DOW (10), DOW (100), and DOW (1000) (parentheses, respectively). The inside shows a specific example when the data of the number of overwrites) is plotted and graphed.

In the graph of Fig. 8, error rate data E1 means error rate data when DOW (overwrite) is performed once at 16.5mw recording power, and error rate data E2 is recording power of 22mw. Error rate data when DOW (overwrite) is performed 1000 times. Since the error rate specification is 280 or less, the recording power lower limit value P1 and the recording power upper limit value P2 at which the curve of the DOW 1 and the curve of the DOW 1000 contact the straight line L1 are the limits of the recording power Pw. Value. Since the recording power lower limit value P1 is 16.8mw and the recording power upper limit value P2 is 21.2mw, the standard power Pws becomes 19mw from Pws = (P1 + P2) / 2. Therefore, for example, when P threshold Pthr is 12.71, kappa κ becomes 1.495 from κ = 19 / 12.71.

Next, an operation example of the embodiment of the recording power adjusting method according to the present invention will be described with reference to FIGS. 3 and 4. The operation flowchart described below is a process for determining the optimal recording power Pwo actually performed in the optical recording / reproducing apparatus after the optimum n power value and kappa κ shown in FIG. 2 are determined. 3, steps S200 to S204 are the same processes as steps S100 to S104 in FIG.

Fig. 9 shows data of the actual recording and measurement / calculation of the optical recording / reproducing apparatus #A when the optimal n power value is set to 5 power, assuming that Pws is 20mv and kappa is 1.51 in step S200. As shown in step S202, the interval of the recording power Pw is performed in 18 steps. Step S206 shows a process of obtaining, as the optimal recording power Pwt (Pwt = Pthr * κ), the upper limit data that can be used to calculate the optimum recording power Pwo among the data shown in FIG.

In step S208, it is the process of judging whether there are more than a predetermined number of conditions and the number of available data among the data shown in FIG. In this case, four pieces of data in which modulation (m) satisfies 0.2 ≤ m as the lower limit of data and recording power (Pw) satisfies the selection condition of optimal recording power (Pwt) or less (Pw ≤ Pwt) It is judged whether it exists abnormally.

If there are four or more pieces of data satisfying the selection condition according to the determination result of step S208, the process proceeds to step S214, and if no exists, the process proceeds to step S210. In step S210, if the number of retries is less than one (No), the process advances to step S212 to reset the recording power Pw, and returns to the process of step S202. On the other hand, if the number of retries is one, it is determined whether or not the optical disk is known (step S230). If the optical disk is already known, the registration Pws is set to Pwo (step S232). If it is not a known optical disc, the recording power acquired from the disc information of the optical disc is set to Pwo (step S234).

Returning to step S214, this processing determines whether or not the correlation coefficient calculated from the data that satisfies the selection condition of step S208 is 0.9 or more. If the correlation coefficient ≥ 0.9, the optimal recording power Pwo is calculated from the entire data satisfying the data selection condition for calculating the optimal recording power Pwo (step S216), and this is set as the optimum recording power Pwo (step S218). ).

That is, P-threshold Pthr is obtained from the slope a and the piece b of the first approximation equation from the data satisfying the selection condition in step S208 among the data shown in FIG. 9. If the actual data shown in FIG. 9 are graph plotted, the actual value is different, but as shown in FIG. 13 or FIG. 14, the data distribution is very close to a straight line, and the difference almost disappears even if the data satisfying the selection condition is extracted.

Since kappa κ is fixed, the optimum recording power Pwo can be calculated at Pwo = Pthr * κ once the P threshold Pthr is obtained. FIG. 10 shows each calculation item (slope (a), piece (b) of the first approximation equation, correlation coefficient, P-threshold) calculated in step S216 from data satisfying the selection condition of step S208 among the data shown in FIG. Pthr and Pthr ^(1/5) , and the values of the optimum recording power Pwo, and Figs. 11 and 12 show other optical recording and reproducing apparatuses having power characteristics of the optical recording and reproducing apparatus #A and the laser diode. The measured data of (#B) and the calculation result are shown.

Both the optical recording and reproducing apparatus #A and the optical recording and reproducing apparatus #B set the recording power start end point setting standard power Pws to 20mw and the kappa κ to 1.51. From these results, even if the values of standard recording power Pws and kappa κ set by the designer of the strategy are the same, the value of modulation (m) varies depending on the individual difference of the optical recording / reproducing apparatus, so that the optimal recording power ( It can be seen that the values of Pwo) are different.

FIG. 15 shows the recording power of the optical recording / reproducing apparatus #A serving as the actual measurement data of FIG. 9 and the optical recording / reproducing apparatus #B serving as the actual measurement data of FIG. Is a graph of. As can be clearly seen from FIG. 15, in the graph of the optical recording / reproducing apparatus #A, jitter is stable near the optimum recording power (Pwo = 19.93) (see FIG. 10), and the graph of the optical recording / reproducing apparatus #B is The jitter is stabilized in the vicinity of the optimum recording power (Pwo = 18.64) (see Fig. 12). Therefore, it can be understood that the recording power at which the jitter value starts to stabilize can be calculated as the optimum recording power Pwo in either optical recording and reproducing apparatus.

Returning to step S214, if the value of the correlation coefficient is smaller than 0.9, the data is deleted one by one from the upper data having a large modulation (m), and this is repeated until the value of the correlation coefficient is larger than 0.9 (step S220, Step S222). If the correlation coefficient? 0.9 is satisfied in step S222, it is determined whether there are four or more valid data after deletion as in step S208 (step S224). If there are four or more pieces of valid data after deletion, the optimum recording power Pwo is calculated (step S226), and the calculated optimal recording power Pwo is set (step S218).

In step S224, if the valid data is smaller than four, it is determined whether the number of retries is one (step S228), and if it is one time, the above-described process of step S230 is performed. On the other hand, if the number of retries is not one, the flow returns to step S200 to reset the recording power time point end point.

Next, the difference between the effect of Unexamined-Japanese-Patent No. 2005-209287 and this embodiment described in "Background art" is demonstrated based on an experiment example. 16 and 18 show data obtained by two optical recording / reproducing apparatuses # 1 and # 2 under the same conditions of Japanese Patent Application Laid-Open No. 2005-209287 and this proposal of the present embodiment. As evaluation and comparison conditions of these data, P-threshold Pthr (A) was calculated from the data in which the modulation (m) value became 0.2 or more, with 5 consecutive data as the range A. From the data of which modulation value (m) became 0.2 or more, the 6th-10th 5th data were made into the range B, and P threshold (Pthr) (B) was computed.

FIG. 17 shows the difference between the source patent and the present proposal in the optical recording and reproducing apparatus # 1 shown in FIG. 16, and FIG. 19 shows the source patent and the present patent in the optical recording and reproducing apparatus # 2 shown in FIG. The difference with the proposal is shown. In any of FIG. 17 and FIG. 19, ΔPthr, which is the difference between the P threshold Pthr (A) in the range A and the P threshold Pthr (B) in the range B, is smaller than the source patent (irregular). Narrow), and the validity of the proposal can be confirmed.

As described in detail above, according to the present embodiment, by selecting the n-th power value that maximizes the correlation coefficient, the data having the most linearity can be obtained from the effective data range, so the range of valid data used for calculation Even if different, there is almost no difference in the value of P threshold Pthr, and as a result, it becomes possible to set the ideal optimum recording power Pwo.

According to the present invention, the n-th power value for creating an optimal first approximation equation can be selected for each optical disk. For this reason, when a test write (OPC: Optimum Power Calibration) operation of a rewritable optical disk is performed within a range in which the recording power individual difference of the optical recording / reproducing apparatus is sufficiently taken into consideration, calculation of the recording power is performed on a predetermined number of data. Compared with the prior art, an optimum recording power with high precision can be obtained. In addition, in the present invention, by using kappa (κ) obtained for each optical disk without using v target and β, which are optical disk information, it is possible to obtain an optimal recording power with high accuracy.

Claims (5)

A recording power adjusting method in an optical recording / reproducing apparatus for performing a test writing to a test writing area of an optical disk to adjust the recording power of a laser diode. N of the modulation (m) and the recording power (Pw) from the various kinds of recording power (Pw) set at the time of the test writing and the modulation (m) calculated from the RF signal at each recording power (Pw). The optical recording / reproducing apparatus is characterized by creating a first-order approximation equation from the relationship between the multiplication value m * Pw ^{n of the} power (n≥2) and Pw ⁿ of the n power (n≥2) of the recording power. How to adjust recording power at The method of claim 1, From the correlations of the n-th power equations calculated above, an n-th power value having the strongest correlation is selected, and a first-order approximation equation is made based on the selected n-th power values, The recording power adjusting method in the optical recording / reproducing apparatus, characterized by calculating the optimum recording power (Pwo) from the first approximation formula created above. The P threshold Pthr required for calculating the optimal recording power Pwo is assuming that the first approximation straight line is y = ax + b. Pthr =-(b / a) ^{(1 / n)} The recording power adjusting method of the optical recording / reproducing apparatus, characterized by the above-mentioned. The optical recording and reproducing apparatus according to claim 2, wherein the optimum recording power (Pwo) is calculated by multiplying the P threshold (Pthr) obtained from the selected n-th power value and the coefficient kappa (κ) obtained for each optical disk. How to adjust the recording power. An optical recording and reproducing apparatus for adjusting a recording power of a laser diode by performing a test writing to a test writing area of an optical disk, Calculation means for calculating correlations of the nth power expressions from various types of recording power Pw set at the time of the test writing, and modulation m calculated from RF signals at the respective recording powers Pw; First-order approximation formula creation means for selecting a strongest n-th power value among correlations of each n-th power equation calculated by the calculation means, and creating a first-order approximation expression based on the selected optimal n-th power value; And an optimum recording power calculating means for calculating an optimum recording power (Pwo) from the first approximation formula created by the first approximation formula generating means.

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