JP2008287783A - Recording power optimizing method and recording power optimizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decide optimum recording power which forms a good mark and a good space in test recording under the limited condition for an optical information recording medium in which manufacturer recommended recording power and also recording power of the previous time are recorded. <P>SOLUTION: Disk management information of an optical information recording medium 1 is read, and manufacturer recommended recording power described in the disk management region is decoded (S3), recording power during the previous time recording is decoded (S4), these powers are compared with each other (S5), test recording power during test recording is calculated by the comparison result (S7), test recording is executed (S8), the signal formed by the test recording is reproduced and jitter values corresponding to respective test recording powers are obtained (S9), an approximation formula indicating relation between respective test recording powers and jotter values corresponding to them is calculated (S10), the optimum recording power in which a jitter value becomes the smallest is calculated from the approximation formula(S11), the calculated optimum recording power is set (S12), and normal data recording is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a recording power optimum for obtaining an optimum recording power by performing test recording on an optical information recording medium in which the recording power recommended by the optical information recording medium manufacturer is recorded in advance and the recording power at the previous recording is recorded. And a recording power optimization apparatus.

  Conventionally, data rewritable optical information recording media include CD-R, CD-RW, DVD-R, DVD-RW, DVD-RAM, MD, MO, and more recently, larger capacity BD- RE and BD-R have been developed and are generally sold. In order to realize high density optical information recording media, BD-RE and BD-R have a narrower track pitch than DVD, and the recorded mark / space length is shortened in the linear density direction, so that the laser wavelength can be shortened. In order to condense a light beam from a light source such as a laser beam into a smaller spot, the numerical aperture of the lens is increased. However, when the numerical aperture of the lens is increased, coma aberration is likely to occur with respect to the warp or tilt of the optical information recording medium. In this case, a thinner cover layer on the reading surface of the optical information recording medium is advantageous in that the occurrence of coma aberration can be reduced.

  The transparent substrate that protects the reading surface (recording surface) of the optical information recording medium is 0.6 mm for DVD, but the cover thickness of this reading surface is 0.1 mm for BD-RE and BD-R, Instead of the transmissive substrate, a transmissive sheet is bonded to the substrate with an adhesive, or a transmissive layer is formed by resin spin coating. In this case, the influence of the thickness error of the transmission sheet and the adhesive or the thickness error of the transmission layer due to spin coating is far greater than that of DVD, and the recording power and recording pulse as recording sensitivity unevenness. It will also affect the width.

  In the optical information recording medium, recording power setting necessary for recording and recording condition setting information recommended by the manufacturer such as recording pulse width are stored in advance. However, the manufacturer recommended recording management information (recording conditions) stored in the optical information recording medium is formed on the substrate as ROM information, and then the recording medium is stacked on the substrate. The characteristics of the recording conditions vary depending on the formation state of the medium.

  That is, even when information is recorded with the same recording power and the same recording pulse width, the size of the recorded mark / space varies depending on the structure of the optical information recording medium, the composition of the recording medium, the ambient temperature, and the like. In particular, in high-density optical recording in which mark edge recording is often performed to provide information at the edge of the mark / space, the change in the recorded mark / space length causes jitter of the reproduced signal and the reproduced data The error rate will be worsened. For this reason, in general, in recording / reproduction of an optical information recording medium, test recording on the optical information recording medium is performed, a recording state obtained from the reproduction signal is determined, and recording conditions are optimized as necessary. Yes.

As a conventional technique for optimizing the recording conditions, for example, there is a technique described in Patent Document 1 for optimizing the recording power. According to Patent Document 1, a test recording of a pattern composed of an unrecorded portion and a recorded portion is performed while sequentially changing the recording power, and information is reproduced from the recorded test pattern, and a signal amplitude corresponding to the recording power P is recorded. , The standardized slope g (P) or the standardized h (P) is obtained, the excess or shortage of the recording power is evaluated based on g (P) or h (P), and the optimum recording power is determined. Looking for.
Further, the technique described in Patent Document 2 below performs test recording, reproduces a test area after the test recording, determines reproduction signal quality and determines an optimum recording power, and then in advance in the optical recording / reproducing apparatus. An optimization correction factor is calculated from the ratio of the standard recording power stored in the memory circuit and the optimum recording power, and the standard erasing power stored in the memory circuit is corrected with the calculated optimization correction factor. ing.
Japanese Patent No. 3124721 (Claim 1) Japanese Patent No. 2697658 (Claim 1)

However, in the technique disclosed in Patent Document 1, in order to reduce the occurrence of coma aberration for increasing the density, an optical information recording medium having a structure in which the cover layer on the reading surface of the optical information recording medium is thin is used. If the inclination g (P) or h (P) cannot be obtained with high accuracy due to uneven thickness of the cover layer, the accuracy is lost.
In the technique disclosed in Patent Document 2, a reproduction test after test recording is performed, an optimum recording power is determined based on a reproduction quality judgment result, and the optimum recording power and the standard recording power stored in the memory circuit are determined. It is described that the standard erasing power is corrected and the optimum erasing power is obtained with the optimization correction rate determined from the ratio. It must be stored in the memory circuit in the apparatus, and it is practically difficult to store the standard recording power corresponding to all types of recording disks in the memory circuit.

  The present invention is an optical information recording medium in which the recording power recommended by the optical information recording medium manufacturer is recorded in advance and the recording power at the time of the previous recording is recorded in test recording under limited recording power conditions. It is an object of the present invention to provide a recording power optimizing method and apparatus capable of determining an optimum recording power for forming a good mark and space on an optical information recording medium and improving a reproduction signal quality.

In order to achieve the above object, the present invention provides an optical information recording medium in which the first recording power recommended by the optical information recording medium manufacturer is recorded in advance and the second recording power at the previous recording is recorded. It is a recording power optimization method for performing test recording against the optimum recording power,
Reading the first and second recording powers recorded on the optical information recording medium;
Comparing the read first and second recording powers;
Determining the first and second recording powers as the optimum recording powers when the first and second recording powers are equal;
When the first and second recording powers are different, the first and second recording powers are set as the first and second test recording powers, and the third test is performed from the first and second recording powers. Calculating the recording power;
Performing test recording on the optical information recording medium with the first, second and third test recording powers;
A physical quantity necessary for calculating the quality of a reproduction signal is obtained from each reproduction signal obtained by reproducing the areas recorded on the optical information recording medium with the first, second, and third test recording powers. Measuring for each of the first, second and third test recording powers;
Relationship between the first, second, and third test recording powers test-recorded on the optical information recording medium and the calculated physical quantities for the first, second, and third test recording powers Obtaining an approximate expression indicating:
Determining a recording power that minimizes the physical quantity in the approximate expression as the optimum recording power;
Prepared.

In order to achieve the above object, the present invention provides the optical information recording in which the first recording power recommended by the optical information recording medium manufacturer is recorded in advance and the second recording power at the previous recording is recorded. A recording power optimization device that performs test recording on a medium and obtains an optimum recording power,
Means for reading the first and second recording powers recorded on the optical information recording medium;
Means for comparing the read first and second recording powers;
Means for determining the first and second recording powers as the optimum recording power when the first and second recording powers are equal;
When the first and second recording powers are different, the first and second recording powers are set as the first and second test recording powers, and the third test is performed from the first and second recording powers. Means for calculating the recording power;
Means for performing test recording on the optical information recording medium with the first, second and third test recording powers;
A physical quantity necessary for calculating the quality of a reproduction signal is obtained from each reproduction signal obtained by reproducing the areas recorded on the optical information recording medium with the first, second, and third test recording powers. Means for measuring each of the first, second, and third test recording powers;
Relationship between the first, second, and third test recording powers test-recorded on the optical information recording medium and the calculated physical quantities for the first, second, and third test recording powers Means for obtaining an approximate expression indicating:
Means for determining, as the optimum recording power, a recording power at which the physical quantity in the approximate expression is minimum;
Prepared.

  The present invention is advantageous when test recording is performed using a limited test recording area because test recording can be performed under a limited number of types of recording power conditions, particularly in a write once optical information recording medium. It is effective and the test recording can be shortened, so that the processing time of the test recording can be shortened. In addition, since the optimum recording power for the optical information recording medium can be determined, information can be written satisfactorily and the reproduction signal quality can be improved.

The best mode for carrying out the present invention will be described below with reference to the drawings.
<First Embodiment>
FIG. 1 is a block diagram showing a first embodiment of an optical recording / reproducing apparatus that realizes a recording power optimization method and apparatus according to the present invention, FIG. 2 is an explanatory diagram showing a laser emission waveform during recording, and FIG. FIG. 4 to FIG. 10 are flowcharts for explaining the test recording process of the first embodiment of the recording power optimization method according to the present invention, and FIGS. 4 to 10 show the first embodiment of the recording power optimization method and apparatus according to the present invention. It is a figure which shows the relationship between recording power and a jitter value when performing the test recording process of a form.

  First, a first embodiment of an optical recording / reproducing apparatus that realizes a recording power optimization method and apparatus according to the present invention will be described with reference to the block diagram of the optical recording / reproducing apparatus shown in FIG. In the optical recording / reproducing apparatus shown in FIG. 1, a phase change type optical information recording medium 1 capable of repeatedly recording / reproducing information is rotationally driven by a spindle motor 2 so that a recording track of the optical information recording medium 1 is optically picked up. By scanning with laser light emitted from (optical PU), digital data of a predetermined data format (here, the mark length / space length is 2T, 3T to 8T with respect to the write clock period: 1T, and the sync data is converted into the sync data. Data including 9T included) is optically recorded and reproduced. Here, an optical recording / reproducing apparatus capable of recording / reproducing the phase change type optical information recording medium 1 will be described as an example, but light capable of recording / reproducing an optical information recording medium using a magneto-optical type or dye-based recording medium will be described. It can also be realized using a recording / reproducing apparatus.

  In the optical pickup 10, laser light from a semiconductor laser 11 that is a laser light source is converted into a parallel light beam by a collimator lens 12, passes through a beam splitter 13, and is applied to a signal recording surface on the optical information recording medium 1 by an objective lens 14. Irradiated to be condensed. The reflected light beam (returned laser light) of the laser light projected and reflected on the signal recording surface of the optical information recording medium 1 is collected by the objective lens 14, then reflected by the beam splitter 13, and cylindrical (condensed). The lens 15 is guided to a photodetector 16 which is a light receiving element.

  The photodetector 16 has a structure in which, for example, the light receiving unit is divided into four parts, and a light detection signal from each of these light receiving units is supplied to the matrix circuit 21 through the preamplifier 20, whereby the sum or difference of these signals is obtained. Is taken out as a so-called RF signal (analog signal), a focus error signal (not shown), a tracking error signal, or the like. Here, the photodetector 16 and the preamplifier 20 have been described separately. However, a photodetector with a built-in preamplifier function may be used. In addition, here, a photodetector having a structure in which the light receiving unit is divided into four parts has been described as an example. However, a photodetector having another structure may be used.

  A focus error signal and a tracking error signal (not shown) are passed through a phase compensation circuit (not shown), and further via a servo drive circuit (not shown), and each driving coil (see FIG. (Not shown), focus servo and tracking servo are performed. The RF signal is a sum signal of output signals from the respective light receiving units, and is supplied to an EQ (equalizer) 22.

  The RF signal output from the matrix circuit 21 is shaped by the EQ 22, and the next binarization circuit 23 compares the RF signal shaped by the EQ 22 with a predetermined threshold value and binarizes the threshold value. Thereby, the RF signal shaped by the EQ 22 is converted into a digital signal by the binarization circuit 23. A PLL (phase lock loop circuit) 24 synchronizes a digital signal with a reference clock signal.

  Area in which information (Disc Information: DI) stored in advance in the disc management area of the optical information recording medium 1 and recording conditions at the time of the previous recording are recorded at the time of starting or immediately before the recording operation The recording power information is demodulated by the recording power information demodulating unit 25 and the recording pulse information is recorded by the recording pulse information demodulating unit 26 among the digital signals obtained through the above path. Is demodulated. The demodulated recording power information is sent to the recording power determination unit 27, and the recording pulse information is sent to the recording pulse determination unit 28.

  Next, recording power information and recording pulse information described in DI will be described using an example of a laser emission waveform during recording shown in FIG. Here, FIG. 2 shows a laser emission waveform when recording mark length / space length = 4T. This laser emission waveform includes a leading pulse (pulse width Ttop), two subsequent pulses (pulse width Tmp), It is composed of multi-pulses including a cooling pulse (power Pco) and an erasing pulse (front end position dTe). In this example, description will be made in a form including information for OPC in addition to recording power information and recording pulse information described in DI stored in advance in the optical information recording medium 1. The following parameters are recorded in the information described in DI.

As recording power information,
“Recording peak power Pind as an index for obtaining the optimum recording peak power Pwo”,
“Multiplier ρ (Pwo = ρ × Pind)”,
“Modulation degree when recording with the recording power described in the recording peak power Pind”,
“Bias power / recording peak power ratio εbw (Pbwo = Pwo × εbw) for obtaining the optimum recording bias power Pbwo”,
“Cooling power / recording peak power ratio εc (Pco = Pwo × εc) for obtaining optimum recording cooling power Pco”,
“Erasing power 1 / recording peak power ratio εe1 (Pe1 = Pwo × εe1) for obtaining optimum erasing power Pe1”,
“Erase power 2 / recording peak power ratio εe2 (Pe2 = Pwo × εe2) for obtaining optimum erase power Pe2”,
“Target ratio κ (κ = Pw / Pthr) of recording peak power Pw and recording threshold peak power Pthr indicating a point on the modulation degree curve at which OPC is executed”.

As the recording pulse information, the following parameters are recorded.
"Lead pulse width Ttop",
“Start pulse front end position information dTtop”,
“Subsequent pulse width Tmp”,
“Erasing pulse front end position information dTe”
(In some cases, each mark length is set according to the space length).
By combining these, a laser emission waveform with respect to the mark length (and space length) is realized as shown in FIG.

  Next, returning to FIG. 1, the recording power determining unit 27 selects the recording power information demodulated by the recording power information demodulating unit 25 or the recording power information stored in the memory 30 obtained via the CPU 29 to perform a test. The setting value of the recording power and the optimum recording power is determined. This output signal is sent to the laser drive circuit 31 and becomes a target value when the semiconductor laser 11 is turned on. The memory 30 includes, for example, a nonvolatile memory such as a ROM that stores system operation programs and data, and a RAM that temporarily stores information read from the optical information recording medium 1 by the optical pickup 10 and a necessary control program. And volatile memory.

  The recording pulse determining unit 28 sends a pulse output for optical modulation to the laser driving circuit 31 based on the recording data from the recording pulse information from the recording pulse information demodulating unit 26. The semiconductor laser 11 is pulse-driven by the laser drive circuit 31 by the combination of the recording power information from the recording power determination unit 27 and the pulse signal at the time of recording from the recording pulse determination unit 28, and recording is performed on the optical information recording medium 1. I can do it.

  The jitter measuring unit 32 reproduces a recording signal obtained by performing test recording on the optical information recording medium 1 as described above, and measures jitter on the recording signal from the PLL 24. The measurement result is sent to the CPU 29, and an approximate expression is calculated between each test recording power and the corresponding jitter value, and used to obtain the recording power that minimizes the jitter value as the optimum recording power in the approximate expression. Is called.

  In this embodiment, the recording power information (DI value) recommended by the disc manufacturer described in the DI, the recording power information (DSI value) at the previous recording described in the DSI, and the DI value and the DSI value are calculated. Test recording with test recording power, obtaining jitter values of these playback signals, calculating an approximate expression indicating the relationship between each test recording power and the corresponding jitter value, and making the jitter value minimum with the approximate expression By calculating the recording power as the optimum recording power, good information is written, and the optimum recording power capable of improving the reproduction signal quality is obtained.

Hereinafter, steps S1 to S12 will be described in detail along the flowchart of FIG.
First, in accordance with a test recording command, the spindle motor 2 is rotationally controlled, the semiconductor laser 11 is turned on (LD ON), and the focus servo and tracking servo are turned ON (step S1). If the servo constant has not been calibrated before the operation of step S1, the process is performed here. Subsequently, the optical pickup 10 seeks to a predetermined address in the disk management area of the optical information recording medium 1, and the servo systems are driven in the order of the spindle servo system, the focus servo system, and the tracking servo system (step S2).

  Next, the recording power information recommended by the disk manufacturer described in the DI is read, decoded by the recording power information demodulator 25 as described above, and sent to the CPU 29 (step S3), and then the previous recording time described in the DSI Is read by the recording power information demodulator 25 as described above and sent to the CPU 29 (step S4). There is no problem in either order of step S3 and step S4. Further, the DI and DSI are read before test recording, and when these are stored in the memory 30, they are read from the memory 30 and sent to the CPU 29.

  The CPU 29 compares the recording power information (DI Power: hereinafter referred to as DI value) recommended by the disk manufacturer described in DI with the recording power information (DSI Power: hereinafter referred to as DSI value) at the time of the previous recording described in DSI (step S5) If the DI value is equal to the DSI value as a result of the comparison (“Yes” in FIG. 3), the DI value = DSI value to the recording power determination unit 27 as the optimum recording power for use in normal data recording (Step S6). As a result of the comparison in step S5, if the DI value and the DSI value are different (“No” in FIG. 3), the DI value and the DSI value, and the test recording power 1 obtained from these according to the difference between the DI value and the DSI value 3 or more kinds of test recording powers including 2 are calculated (step S7). A method for calculating the test recording powers 1 and 2 will be described with reference to FIGS.

First, in FIG. 4 to FIG. 6, three types of test recording power (DI value, DSI value, test recording power 1) including the DI value, the DSI value, and the test recording power 1 calculated from these DI value and DSI value are shown. The case of using will be described. Here, the recording power refers to the “optimal recording peak power Pwo” described in FIG. 2, and the ratio (ε) described in DI is used for the light intensity of other recording powers. FIG. 4 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is relatively large, DI value <DSI value, and test recording is performed with three types of test recording power. In this case, as the test recording power 1, a value between the DI value and the DSI value is calculated, and it is desirable to select the midpoint.
Test recording power 1 = (DSI + DI) / 2
In FIG. 4, although it is described as DI value <DSI value, when DI value> DSI value, if the difference is relatively large, calculation is performed by switching the relationship between DI value and DSI value by the same method.

FIG. 5 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is relatively small, DI value> DSI value, and test recording is performed with three types of test recording power. In this case, the recording power smaller than the DSI value is calculated as the test recording power 1,
Test recording power 1 = DSI value− (DI value−DSI)
It is desirable to select such that

FIG. 6 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is relatively small, DI value <DSI value, and test recording is performed with three types of test recording powers. In this case, the recording power larger than the DSI value is calculated as the test recording power 1, and
Test recording power 1 = DSI value + (DSI value−DI value)
It is desirable to select such that

Next, referring to FIG. 7 to FIG. 10, test recording powers 1 and 2 are calculated from the DI value and DSI value, and four types of test recording power (DI value, DSI value, test recording power 1 and 2) are obtained. The case of using will be described. FIG. 7 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is large, DI value <DSI value, and test recording is performed with four types of test recording power. In this case, two intermediate values between the DI value and the DSI value are calculated as test recording powers 1 and 2, and the recording power is calculated as two intermediate values between the DI value and the DSI value. 2, it is desirable to select a value that divides the difference between the DSI value and the DI value at equal intervals.
Test recording power 1 = DI value + (DSI value−DI value) / 3
Test recording power 2 = DSI value− (DSI value−DI value) / 3
In FIG. 7, although DI value <DSI value is described, when DI value> DSI value is large, calculation is performed by switching the relationship between DI value and DSI value in the same manner.

FIG. 8 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is relatively small, DI value <DSI value, and test recording is performed with four types of test recording power. In this case, the test recording power 1 between the DI value and the DSI value and the test recording power 2 larger than the DSI value are calculated.
Test recording power 1 = DSI value− (DSI value−DI value) / 2
Test recording power 2 = DSI value + (DSI value−DI value) / 2
It is desirable to select such that

FIG. 9 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is relatively small, DI value> DSI value, and test recording is performed with four types of test recording power. In this case, a test recording power 1 smaller than the DSI value and a test recording power 2 between the DI value and the DSI value are calculated.
Test recording power 1 = DSI value− (DI value−DSI value) / 2
Test recording power 2 = DSI value + (DI value−DSI value) / 2
It is desirable to select such that

FIG. 10 shows the relationship between the recording power and the jitter value when the difference between the DI value and the DSI value is small, DI value <DSI value, and test recording is performed with four types of test recording power. In this case, the test recording power 1 below the DI value and the test recording power 2 above the DSI value are calculated.
Test recording power 1 = DI value− (DSI value−DI value)
Test recording power 2 = DSI value + (DSI value−DI value)
It is desirable to select such that In FIG. 10, although it is described as DI value <DSI value, when DI value> DSI value, if the difference is small, the calculation is performed by switching the relationship between DI value and DSI value by the same method.

  So far, an example of a method for calculating the test recording powers 1 and 2 in the test recording has been described using the first embodiment, but it can be applied to the present invention even if the recording power is obtained by a calculation method other than the above. Not too long.

  Subsequently, test recording is performed using the above-described test recording power (DI, DSI, test recording power 1 (and further 2)) (step S8), and a recording signal formed by the test recording is reproduced, and each test recording is performed. Jitter value corresponding to power (DI, DSI, test recording power 1 (or 2)) is acquired (step S9), and test recording power (DI, DSI, test recording power 1 (or 2)) and corresponding to it An approximate expression indicating the relationship between the above-described jitter values is calculated (step S10). Here, as for the approximate expression, the least square method using a second-order polynomial is used when there are three types of test recording powers as described in FIGS. 4 to 10, and 3 when the test recording power is four types. The least square method using the following polynomial may be used. Further, when there are five or more types of test recording power, a least square method using a third or higher order polynomial may be used.

  Returning to FIG. 3, after calculating the approximate expression, the recording power (the “calculated value” in FIGS. 4 to 10) that minimizes the jitter value is calculated from the approximate expression (step S11). The recording power calculated in step S11 is set and sent to the recording power determination unit 27 as the optimum recording power for use in normal data recording (step S12). This makes it possible to use a recording power for performing optimum recording during normal data recording.

  The optimum recording power (calculated value) obtained here can be recorded in the DSI area or the like in the disk management area of the optical information recording medium 1 and used for the next recording. Further, storing together with the disc type or the like in the memory 30 in the optical recording / reproducing apparatus can also be used for the recording power when the optical information recording medium 1 is recorded next time. The timing when these recording power optimization methods are performed is assumed to be performed before normal data recording, and may be performed at the time of starting or immediately before recording. Although an example of a method for calculating the test recording powers 1 and 2 in the test recording has been described using the second embodiment, it goes without saying that the present invention can be applied even if the recording power is obtained by a calculation method other than the above. Absent.

<Second Embodiment>
FIG. 11 is a block diagram showing a second embodiment of an optical recording / reproducing apparatus for realizing a recording power optimization method and apparatus according to the present invention. FIG. 12 shows a second embodiment of the recording power optimization method according to the present invention. FIG. 13 to FIG. 19 are flowcharts for explaining the test recording process of the embodiment, and FIG. 13 to FIG. 19 show the recording power and error when the test recording process of the second embodiment of the recording power optimization method and apparatus according to the present invention It is a figure which shows the relationship of a rate.

  First, a second embodiment of the optical recording / reproducing apparatus that realizes the recording power optimization method and apparatus according to the present invention will be described with reference to the block diagram of the optical recording / reproducing apparatus shown in FIG. The operation is the same as the block diagram of the optical recording / reproducing apparatus shown in FIG. 1, but the following description focuses on the differences.

  The error rate measuring unit 33 reproduces the recording signal obtained by performing test recording on the optical information recording medium 1 as described above, and measures the error rate for the recording signal from the PLL 24. The measurement result is sent to the CPU 29, and an approximate expression showing the relationship between each test recording power at the time of test recording and the corresponding error rate is calculated, and the recording power that minimizes the error rate in the approximate expression is optimized. Used for recording power.

  In this embodiment, the recording power information (DI value) recommended by the disc manufacturer described in the DI, the recording power information (DSI value) at the previous recording described in the DSI, and the DI value and the DSI value are calculated. Test recording with test recording power, obtaining the error rate of these playback signals, calculating an approximate expression showing the relationship between each test recording power and the corresponding error rate, By calculating the recording power as the optimum recording power, good information is written, and the optimum recording power capable of improving the reproduction signal quality is obtained.

  Hereinafter, steps S21 to S32 will be described in detail along the flowchart of FIG. First, since the process of step S21-S27 is the same as step S1-S7 shown in FIG. 3, description is abbreviate | omitted. In the second embodiment, if the DI value is equal to the DSI value (“Yes” in FIG. 12) as a result of the comparison in step S25, DI value = DSI value is used for normal data recording. The optimum recording power is sent to the recording power determination unit 27 (step S26). As a result of the comparison in step S25, if the DI value and the DSI value are different (“No” in FIG. 12), the DI value and the DSI value, and the test recording power 1 obtained from these according to the difference between the DI value and the DSI value 3 or more kinds of test recording powers including 2 are calculated (step S27). A method for calculating the test recording powers 1 and 2 will be described with reference to FIGS.

First, in FIG. 13 to FIG. 15, three types of test recording power (DI value, DSI value, test recording power 1) including the DI recording value and the DSI value and the test recording power 1 calculated from these DI value and DSI value are shown. The case of using will be described. Here, the recording power refers to the “optimal recording peak power Pwo” described in FIG. 2, and the ratio (ε) described in DI is used for the light intensity of other recording powers. FIG. 13 shows the relationship between the recording power and error rate when the difference between the DI value and the DSI value is relatively large, DI value <DSI value, and test recording is performed with three types of test recording power. In this case, as the test recording power 1, a value between the DI value and the DSI value is calculated, and it is desirable to select the midpoint.
Test recording power 1 = (DSI + DI) / 2
In FIG. 13, although DI value <DSI value is described, if DI value> DSI value is relatively large, the calculation is performed by switching the relationship between DI value and DSI value in the same manner.

FIG. 14 shows the relationship between recording power and error rate when the difference between the DI value and the DSI value is relatively small, DI value> DSI value, and test recording is performed with three types of test recording power. In this case, the recording power smaller than the DSI value is calculated as the test recording power 1,
Test recording power 1 = DSI value− (DI value−DSI value)
It is desirable to select such that

FIG. 15 shows the relationship between the recording power and the error rate in the case where the difference between the DI value and the DSI value is relatively small, DI value <DSI value, and test recording is performed with three types of test recording power. In this case, the recording power larger than the DSI value is calculated as the test recording power 1, and
Test recording power 1 = DSI value + (DSI value−DI value)
It is desirable to select such that

Next, referring to FIGS. 16 to 19, the test recording powers 1 and 2 are calculated from the DI value and the DSI value, and four types of test recording power (DI value, DSI value, test recording power 1 and 2) are obtained. The case of using will be described. FIG. 16 shows the relationship between the recording power and the error rate in the case where the difference between the DI value and the DSI value is large, DI value <DSI value, and test recording is performed with four types of test recording power. In this case, two intermediate values between the DI value and the DSI value are calculated as test recording powers 1 and 2, and the recording power is calculated as two intermediate values between the DI value and the DSI value. 2, it is desirable to select a value that divides the difference between the DSI value and the DI value at equal intervals.
Test recording power 1 = DI value + (DSI value−DI value) / 3
Test recording power 2 = DSI value− (DSI value−DI value) / 3
In FIG. 16, although described as DI value <DSI value, if DI value> DSI value, but the difference is large, the relationship between DI value and DSI value is calculated by the same method.

FIG. 17 shows the relationship between the recording power and the error rate in the case where the difference between the DI value and the DSI value is relatively small, DI value <DSI value, and test recording is performed with four types of test recording power. In this case, the test recording power 1 between the DI value and the DSI value and the test recording power 2 larger than the DSI value are calculated.
Test recording power 1 = DSI value− (DSI value−DI value) / 2
Test recording power 2 = DSI value + (DSI value−DI value) / 2
It is desirable to select such that

FIG. 18 shows the relationship between the recording power and the error rate when the difference between the DI value and the DSI value is relatively small, DI value> DSI value, and test recording is performed with four types of test recording power. In this case, a test recording power 1 smaller than the DSI value and a test recording power 2 between the DI value and the DSI value are calculated.
Test recording power 1 = DSI value− (DI value−DSI value) / 2
Test recording power 2 = DSI value + (DI value−DSI value) / 2
It is desirable to select such that

FIG. 19 shows the relationship between the recording power and the error rate in the case where the difference between the DI value and the DSI value is small, DI value <DSI value, and test recording is performed with four types of test recording power. In this case, the test recording power 1 below the DI value and the test recording power 2 above the DSI value are calculated.
Test recording power 1 = DI value− (DSI value−DI value)
Test recording power 2 = DSI value + (DSI value−DI value)
It is desirable to select such that In FIG. 19, although it is described as DI value <DSI value, when DI value> DSI value, if the difference is small, the calculation is performed by exchanging the relationship between DI value and DSI value by the same method.

  Subsequently, test recording is performed using the above-described test recording power (DI, DSI, test recording power 1 (or 2)) (step S28), and a recording signal formed by the test recording is reproduced, and each test recording is performed. The error rate corresponding to the power (DI, DSI, test recording power 1 (or 2)) is acquired (step S29), and the test recording power (DI, DSI, test recording power 1 (or 2)) and corresponding to it. An approximate expression indicating the relationship between the error rate and the error rate is calculated (step S30). Here, as for the approximate expression, the least square method using a second-order polynomial is used when there are three types of test recording power as described in FIGS. 13 to 19, and 3 when the test recording power is four types. The least square method using the following polynomial may be used. Further, when there are five or more types of test recording power, a least square method using a third or higher order polynomial may be used.

  Returning to FIG. 12, after calculating the approximate expression, the recording power that minimizes the error rate ("calculated value" in FIGS. 13 to 19) is calculated from the approximate expression (step S31). The recording power calculated in step S31 is set and sent to the recording power determination unit 27 as the optimum recording power for use in normal data recording (step S32). This makes it possible to use a recording power for performing optimum recording during normal data recording.

  The optimum recording power (calculated value) obtained here can be recorded in the DSI area or the like in the disk management area of the optical information recording medium 1 and used for the next recording. Further, storing together with the disc type or the like in the memory 30 in the optical recording / reproducing apparatus can also be used for the recording power when the optical information recording medium 1 is recorded next time. The timing when these recording power optimization methods are performed is assumed to be performed before normal data recording, and may be performed at the time of starting or immediately before recording. Although an example of a method for calculating the test recording powers 1 and 2 in the test recording has been described using the second embodiment, it goes without saying that the present invention can be applied even if the recording power is obtained by a calculation method other than the above. Absent.

  According to the present invention, as described above, since test recording under a limited number of test recording power conditions is sufficient, it is advantageous when performing test recording using a limited test recording area, particularly write-once type optical information. This is advantageous for the recording medium, and the test recording processing time can be shortened because the test recording can be shortened. In addition, the optimum recording power for the optical information recording medium can be determined, and the reproduction signal quality can be improved by writing information satisfactorily.

1 is a block diagram showing a first embodiment of an optical recording / reproducing apparatus that realizes a recording power optimization method according to the present invention. It is explanatory drawing which shows the laser light emission waveform at the time of recording. 6 is a flowchart for explaining processing in the first embodiment of the recording power optimization method according to the present invention; 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. 3 is an example of a graph showing the relationship between the recording power and the jitter value when test recording is performed in the first embodiment of the recording power optimization method according to the present invention. It is a block diagram which shows 2nd Embodiment of the optical recording / reproducing apparatus which implement | achieves the recording power optimization method based on this invention. It is a flowchart for demonstrating the process in 2nd Embodiment of the recording power optimization method based on this invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention. 6 is an example of a graph showing a relationship between a recording power and an error rate value when test recording is performed in the second embodiment of the recording power optimization method according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical information recording medium 2 Spindle motor 10 Optical pick-up 11 Semiconductor laser 12 Collimating lens 13 Beam splitter 14 Objective lens 15 Cylindrical (condensing) lens 16 Photo detector 20 Preamplifier 21 Matrix circuit 22 EQ (Equalizer)
23 Binarization Circuit 24 PLL (Phase Lock Loop)
25 Recording Power Information Demodulation Unit 26 Recording Pulse Information Demodulation Unit 27 Recording Power Determination Unit 28 Recording Pulse Determination Unit 29 CPU
30 Memory 31 Laser Drive Circuit 32 Jitter Measurement Unit 33 Error Rate Measurement Unit

Claims (3)

Test recording is performed on the optical information recording medium in which the first recording power recommended by the optical information recording medium manufacturer is recorded in advance and the second recording power at the previous recording is recorded, and the optimum recording power is set. A recording power optimization method to be sought,
Reading the first and second recording powers recorded on the optical information recording medium;
Comparing the read first and second recording powers;
Determining the first and second recording powers as the optimum recording powers when the first and second recording powers are equal;
When the first and second recording powers are different, the first and second recording powers are set as the first and second test recording powers, and the third test is performed from the first and second recording powers. Calculating the recording power;
Performing test recording on the optical information recording medium with the first, second and third test recording powers;
A physical quantity necessary for calculating the quality of a reproduction signal is obtained from each reproduction signal obtained by reproducing the areas recorded on the optical information recording medium with the first, second, and third test recording powers. Measuring for each of the first, second and third test recording powers;
Relationship between the first, second, and third test recording powers test-recorded on the optical information recording medium and the calculated physical quantities for the first, second, and third test recording powers Obtaining an approximate expression indicating:
Determining a recording power that minimizes the physical quantity in the approximate expression as the optimum recording power;
Recording power optimization method provided. Test recording is performed on the optical information recording medium in which the first recording power recommended by the optical information recording medium manufacturer is recorded in advance and the second recording power at the previous recording is recorded, and the optimum recording power A recording power optimization device to be obtained,
Means for reading the first and second recording powers recorded on the optical information recording medium;
Means for comparing the read first and second recording powers;
Means for determining the first and second recording powers as the optimum recording power when the first and second recording powers are equal;
When the first and second recording powers are different, the first and second recording powers are set as the first and second test recording powers, and the third test is performed from the first and second recording powers. Means for calculating the recording power;
Means for performing test recording on the optical information recording medium with the first, second and third test recording powers;
A physical quantity necessary for calculating the quality of a reproduction signal is obtained from each reproduction signal obtained by reproducing the areas recorded on the optical information recording medium with the first, second, and third test recording powers. Means for measuring each of the first, second, and third test recording powers;
Relationship between the first, second, and third test recording powers test-recorded on the optical information recording medium and the calculated physical quantities for the first, second, and third test recording powers Means for obtaining an approximate expression indicating:
Means for determining, as the optimum recording power, a recording power at which the physical quantity in the approximate expression is minimum;
A recording power optimization device.   3. The recording power optimization apparatus according to claim 2, wherein the physical quantity necessary for calculating the quality of the reproduction signal is a jitter value or an error rate of the reproduction signal.

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