RU2375765C2 - Method and device for determining recording power - Google Patents

Abstract

FIELD: physics; computer engineering.

SUBSTANCE: in the method, test data are recorded on an information carrier for several values of recording power. The signal modulation depth, corresponding to each value of test recording power, is then measured. After this the product of the n-power of each value of test recording power and the corresponding modulation depth are calculated. The value of the first recording power is then calculated based on correlation between the set of values of test recording power and the set of multiplications. Finally, recording power is then calculated based on the first power recording.

EFFECT: design of an efficient method of determining power of and optical beam with the aim of recording data onto a carrier.

4 cl, 24 dwg

Description

Technical field

The present invention relates to a method for determining recording power and a device for determining recording power for determining recording power for recording data on an information storage medium.

State of the art

Optical discs are known as storage media (medium) for recording data. An optical disc device irradiates an optical disc with an optical beam to record data or reproduce data recorded on the optical disc. Even if optical disks and optical disk devices are manufactured in the same way, there are individual differences between optical disks and optical disk devices. Due to individual differences, there may be a problem in that the data cannot be recorded properly on the optical disc or the data recorded on the optical disc cannot be properly reproduced.

As one of the ways to prevent such a problem, an approach is known that consists in determining the recording power in such a way that it corresponds to an individual optical disk and an individual optical disk device, for example, when installing an optical disk.

FIG. 16 is a schematic diagram showing a conventional optical disk 601. As shown in FIG. 16, the optical disk 601 has a track 602 formed thereon in a helical manner. By irradiating the track 602 with an optical beam having a variable recording power, a plurality of marks and a plurality of gaps are formed on the track 602. Thus, data is recorded. The optical disk 601 includes a user data area used to record data by the user, and a recording power determination area used to determine the recording power of the optical beam. A recording power determination area is provided in a region other than the user data area (in particular, the innermost region or the outermost region of the optical disc 601).

FIG. 17 is a schematic diagram showing a conventional optical disk device 700. The optical disk device 700 includes an optical head 702, a reproducing section 704, a demodulation / ECC (FEC, error correction coding) circuit 706, a recording power determination section 708, a section 710 setting the recording power, the laser control circuit 712 and the recording data generating section 714.

When the optical disk 601 is mounted on the optical disk device 700, the type of optical disk 601 is identified and the optical disk 601 is rotated. The optical head 702 has a semiconductor laser (not shown). During rotation, the optical disk 601 is illuminated by an optical beam emitted from the semiconductor laser of the optical head 702.

To write data to the optical disk 601, the optical head 702 illuminates the optical disk 601 with an optical beam having a predetermined recording power to form marks on the optical disk 601. In this example, the data of the modulation system with recording length limitation (1, 7) are recorded by the edge recording method (borders) labels. In this case, seven types of marks and spaces are formed on the optical disk 601 on the basis of a reference (reference) cycle T, which is 2T at least and 8T at most.

To read data from the optical disk 601, the optical head 702 illuminates the optical disk 601 with an optical beam having a reproduction power that is lower than the recording power and receives the light reflected by the optical disk 601. The optical head 702 performs optical / electrical conversion of the received light so that generate a signal indicating the data recorded on the optical disk 601. The playback section 704 measures the modulation coefficient of the signal generated by the optical head 702, and digitizes the signal l formed by the optical head 702. The modulation coefficient is described below with reference to Fig.19.

The demodulation / ECC circuit 706 demodulates the signal digitized by the reproducing section 704 and corrects the errors. The recording power determining section 708 determines the recording power for recording data based on the modulation coefficient measured by the reproducing section 704. The recording power setting section 710 sets the recording power determined by the recording power determining section 708 in the laser control circuit 712. The recording data generating section 714 generates data to be recorded on the optical disk 601. The laser control circuit 712 controls the optical head 702 to write data generated by the recording data generating section 714 to the optical disk 601 at a recording power set by the recording power setting section 710 .

FIG. 18 is a schematic diagram showing a reproducing section 704 in a conventional optical disc device 700. As shown in FIG. 18, the reproducing section 704 includes a preamplifier 801, a sampling and storage circuit 802, an analog-to-digital converter 803, an arithmetic operator 804 and section 805 generating binary data.

The binary data generating section 805 digitizes the signal generated by the optical disk 702 to generate digitized data (binary data), and provides a signal 705 indicating these binary data to the demodulation / ECC circuit 706 and the recording power determining section 708.

A preamplifier 801 amplifies the signal generated by the optical head 702. A sampling and storage circuit 802 samples a signal amplified by the preamplifier 801 and stores the peak value and lower value of the signal. An analog-to-digital converter 803 digitizes the peak value and the lower value stored by the sample and store circuit 802. An arithmetic operator (arithmetic operator execution unit) 804 performs an arithmetic operation on a digitized peak value and a lower value to obtain a modulation coefficient.

Fig. 19 is a schematic diagram showing the waveform that is output from the preamplifier 801. As shown in Fig. 19, the modulation coefficient is represented as (AB) / A, where amplitude A is the amplitude of the signal level when there is no the optical beam is not emitted by the semiconductor laser in the optical head 702, or signal level, when no influence is exhibited by the light reflected from the optical disk 601, even if the optical disk 601 is illuminated by an optical beam having a reproduction power emitted by by a semiconductor laser of the optical head 702, to a signal level corresponding to the mark; and the amplitude B is the amplitude from the signal level when no optical beam is emitted by the semiconductor laser of the optical head 702, to the signal level corresponding to the gap.

Returning to FIG. 17, a conventional method for determining recording power is described.

A constant parameter is recorded on the optical disk 601 for use in order to determine the recording power. The optical head 702 generates a signal 703 indicating this constant parameter (hereinafter referred to as a "predetermined value") read from the optical disk 601, and provides a signal 703 to the playback section 704. The binary data generating section 805 of the reproducing section 704 generates a binary signal 705 obtained by binarizing a signal 703 indicating a predetermined value, and provides a signal 705 to the recording power determining section 708.

The recording power setting section 710 sets the test recording power of the optical beam in the laser control circuit 712. The recording power setting section 710 sets eight different test recording power values A-H. In this example, the test recording power A is the highest power, and the test recording power decreases from the value B of the test recording power to the value H of the test recording power.

The recording data generating section 714 generates test data and provides a signal 715 indicating the generated test data to the laser control circuit 712. The laser control circuit 712 controls the optical head 702 to record test data substantially one revolution of the track continuously from a predetermined position in the recording power determination area of the optical disk 601. The recording data generating section 714 generates test data so that the optical head 702 continuously generates 8T marks and 8T of the gaps on the optical disk 601. Test data is repeated in a repeating manner per essentially one revolution of the optical disk 601 at A-H test recording powers. FIG. 20 depicts regions of an optical disk 601 corresponding to A-H values of test recording power, with characters “A” through “H”.

When the test data recording is completed, the optical head 702 illuminates the optical disk 601 with an optical beam having a reproduction power. By this, the test data recorded on the track is read and a signal is generated indicating the test data. The amplitude of the signal generated by the optical head 702 varies in accordance with whether marks are formed on the optical disk 601. The signal 703 generated by the optical head 702 is input to the reproducing section 704.

With reference to FIG. 18: the pre-amplifier 801 in the playback section 704 amplifies the signal 703. The sampling and storage circuit 802 stores the peak value and lower value of the signal amplified by the pre-amplifier 801. An analog-to-digital converter 803 digitizes the peak value and the lower signal value stored 802 sampling and storage circuitry. The arithmetic operator 804 performs an arithmetic operation on the digitized peak value and the lower value to obtain a signal modulation coefficient. Since the amplitude of the signal 703 is different in accordance with the values A – H of the test recording power, the modulation coefficient is also different in accordance with the values A – H of the test recording power. The arithmetic operator 804 generates a signal 707 indicating the modulation coefficients of the signal, and provides a signal 707 to the recording power determination section 708.

The recording power determining section 708 determines the recording power based on the modulator coefficients corresponding to the test recording power values A — H by one of two conventional methods for determining the recording power described below.

21 is a view for describing a first conventional method for determining recording power and is a graph illustrating the relationship between test recording power and modulation coefficient. According to a first conventional method for determining recording power, the recording power determining section 708 selects a recording power P0 corresponding to a modulation coefficient M0 based on a correlation between a plurality of test recording power values and a plurality of modulation coefficient values corresponding to a plurality of test recording power. Section 70 determine the recording power calculates the product of the recording power P0 and a predetermined value read from the optical disk 601, and thus determines the recording power used to record data. The recording power determining section 708 provides a signal 709 indicating the calculated recording power to the recording power setting section 710.

22 is a view for describing a second conventional method for determining recording power and is a graph illustrating the relationship between (i) test recording power and (ii) the product of modulation coefficient and recording power. According to a second conventional method for determining recording power, the recording power determining section 708 calculates the product of each of a plurality of test recording powers and a modulation coefficient corresponding thereto, and thereby constructs (creates) an approximated line indicating a correlation between (i) the test recording power and (ii ) the product of the modulation coefficient and the value of the test recording power. Then, the recording power determining section 708 obtains the recording power Pthr at which the product is 0 on this approximated line. Then, the recording power determining section 708 calculates the product of the recording power Pthr and the predetermined value read from the optical disk 601, and determines the recording power used for recording data. The recording power determining section 708 outputs a signal 709 indicating the calculated value to the recording power setting section 710.

Disclosure of invention

Problems to be Solved by the Present Invention

However, a suitable recording power cannot be determined by either the first conventional method of determining the recording power or the second conventional method of determining the recording power.

In the case where the recording power determining section 708 determines the recording power according to the first conventional recording power determination method, the recording power determining section 708 cannot determine the corresponding recording power when, for example, there is a relative tilt between the optical disk 601 and the optical head 702. Hereinafter, with reference to FIG. 23, recording power is described when there is such a slope.

23 is a graph illustrating the relationship between recording power and modulation coefficient. In the graph of FIG. 23, the solid line 1101 represents the result obtained for the case where there is no slope during data recording or while reading recorded data. Solid line 1102 represents the result obtained for the case when there is a slope during data recording, but there is no slope during data reading. The solid line 1103 represents the result obtained for the case when there is a slope both during data recording and during data reading. The modulation coefficient is lower when there is a slope than when there is no slope. In the case where there is no slope during data reading, but there is a slope during data recording, the modulation coefficient corresponding to the recording power H, which is the smallest among the eight write power values, cannot be measured. Similarly, in the case where there is a slope both during data recording and during data reading, the modulation coefficient corresponding to the recording power H cannot be measured.

Test data is written and read before user data is written. Test data is read immediately after recording. Accordingly, when the test data is written and read, while there is a relative slope, the result represented by the solid line 1103 in FIG. 23 is obtained. When determining the recording power by the first conventional method for determining the recording power, the recording power determining section 708 selects the recording power P1103 corresponding to the modulation coefficient M0. This result was obtained under the influence of the slope during the recording of test data and also the slope when reading the test data (hereinafter referred to as "during the reading of test data").

In the case where there is a slope during recording of test data, it is considered that there is also a slope during recording of user data. However, when reading user data, there is not necessarily a slope. It is very rare that user data is read immediately after writing. In many cases, user data is read by another optical disk device or after the optical disk is reinstalled on the optical disk device. Therefore, there is no tilt while reading user data. Accordingly, to determine the recording power, only the influence of the slope during the recording of test data should be considered. There is no need to consider the effect of tilt while reading test data. Therefore, the recording power to be selected when there is a relative slope is not the recording power P1103, but the recording power P1102 in FIG. 23. When determining the recording power by the first conventional method for determining the recording power, the recording power determining section 708 selects the recording power P1103, which is greater than the recording power P1102. Therefore, the optical head 702 records data with unnecessarily high power. As a result, when using the first conventional method for determining the recording power, the optical disc 601 is degraded too quickly by re-recording.

When using the second conventional method for determining the recording power to determine the recording power, the following occurs, as shown in FIG. When the recording power determination section 708 selects four large test recording power values from eight test recording values and constructs an approximate line indicating a correlation between (i) each of these four test recording power values and (ii) the product of the modulation coefficient and each of these four values recording power, recording power at which the product is 0 on the approximated line is the recording power Pthr1. Conversely, when the recording power determination section 708 selects four lower test recording power values from eight test recording power values and constructs an approximate line indicating a correlation between (i) each of these four test recording power values and (ii) the product of the modulation coefficient and each of of these four values of the recording power, the recording power at which the product is 0 on the approximated line is the recording power Pthr2.

As is clear from FIG. 24, the recording power at which the product is 0 on the approximated line is significantly different compared to the test recording power. Namely, when determining the recording power by the second conventional way of determining the recording power, the recording power to be determined is significantly different depending on the test recording power that is used to record the test data, and depending on the value of the test recording power, the result of which is used to determining recording power. Accordingly, when using the second conventional method for determining the recording power, the recording power determining section 708 cannot unambiguously determine a suitable recording power. In addition, when the recording power determining section 708 determines a recording power greater than a suitable recording power, the optical disc deteriorates unnecessarily quickly. Conversely, when the recording power determining section 708 determines a recording power lower than a suitable recording power, data cannot be recorded properly on the optical disc.

The present invention, made in light of the problems described above, has the task of providing a method for determining recording power and a device for determining recording power to determine a suitable recording power.

Problem Solving Tools

The method for determining the recording power according to the present invention for determining the recording power of an optical beam for recording data on an information storage medium (medium) comprises the step of recording test data, comprising recording test data on an information storage medium with a plurality of test recording powers; the step of measuring the modulation coefficient, which consists in reading the test data recorded at each of the plurality of test recording power values, generating a signal and measuring the modulation coefficient of the signal corresponding to each of the plurality of test recording power values; the step of obtaining the product, which consists in calculating the product of the nth degree of each of the many values of the test recording power and the modulation coefficient corresponding to it, thereby obtaining a set of products corresponding to the set of values of the test recording power, where n is the value of the exponent and is a real number, different from 1; a step of calculating a first recording power to calculate a first value of a recording power based on a correlation between a plurality of test recording power values and a plurality of products; and a step of calculating the recording power to calculate the recording power based on the first recording power.

In one embodiment, the step of calculating the first recording power includes the step of constructing an approximated line indicating a correlation between the plurality of test recording powers and the plurality of products, and calculates a first recording power at which the product is 0 on the approximated line.

In one embodiment, at the stage of obtaining the product, the exponent n is equal to 2.

In one embodiment, the method for determining the recording power further comprises the step of reading a value for reading a value recorded on the information storage medium (medium). The information storage medium (medium) has a Pind value, a ρ value, and a k value recorded thereon; the step of reading the value includes the step of reading the value of Pind, the value of ρ, and the value of k; the step of recording test data includes the step of setting the range of the plurality of test recording powers to the range of 0.9-1.1 of the Pind value; the step of calculating the first recording power includes the step of constructing an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and calculating a first recording power at which the product is 0 on the approximated line; and this step of calculating the recording power includes a step of calculating the product of the value of the first recording power, (-1 / (value k) +2) and the value of ρ.

In one embodiment, the method for determining the recording power further comprises the step of reading a value for reading a value recorded on the information storage medium. The information storage medium has an exponent n recorded on it; this step of reading the value includes the step of reading the exponent n; and the step of obtaining the product includes the step of using the read exponent n degree.

In one embodiment, the step of recording test data includes the step of recording test data so that the signal generated in the step of measuring the modulation coefficient includes a plurality of one-cycle cycle signals.

In one embodiment, the information storage medium has a plurality of marks and a plurality of gaps formed thereon by an optical beam that is modulated; and the step of recording test data includes the step of generating a plurality of marks, so that the amplitude of the signal generated in the step of measuring the modulation coefficient is substantially the same as the amplitude of the longest mark of the plurality of marks formed on the information storage medium.

In one embodiment, the information storage medium has a plurality of tracks formed concentrically or helically thereon.

In one embodiment, the step of obtaining a work includes the step of obtaining a plurality of works corresponding to a plurality of test recording power values with respect to each of a plurality of values provided as an exponent n; this method of determining the recording power further comprises the step of determining a value for calculating the linearity of the correlation between the plurality of test recording power values and the plurality of products with respect to each of the plurality of values, thereby calculating the plurality of linearity values corresponding to this plurality of values, and determining one of this plurality of values, which corresponds to the largest linearity value; and the step of calculating the first recording power includes the step of calculating the first recording power using a plurality of products corresponding to the plurality of test recording power values with respect to one of the plurality of values that corresponds to the largest linearity value.

In one embodiment, the plurality of values includes a first value and a second value; and the first value is 2, and the second value is 3.

In one embodiment, the method for determining the recording power further comprises the step of reading a value for reading a value recorded on the information storage medium. The information storage medium has a Pind value, a ρ value, and a k value recorded thereon; the step of reading the value includes the step of reading the value of Pind, the value of ρ, and the value of k; a test data recording step includes: setting a range of a plurality of test recording powers to a range of 0.9 to 1.1 from the Pind value; and the step of calculating the first recording power includes the step of constructing an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and calculating a first recording power at which the product is 0 on the approximated line.

In one embodiment, the step of calculating the recording power includes the steps according to which if the linearity when the exponent n is equal to 2 is higher than the linearity when the exponent n is equal to 3, the product of the first recording power is calculated (-1 / (k value) +2) and ρ values; and in the case where the linearity, when the exponent n is equal to 3, is higher than the linearity, when the exponent n is equal to 2, the product of the value of the first recording power is calculated, (3 × (value k) -2) / (2 × (value k) -1) and the values of ρ.

In one embodiment, the plurality of values includes a first value and a second value; and the step of determining the value includes the step of setting a first group of test recording power values with respect to the first value, selecting at least two test recording values from a plurality of test recording power values, and setting a first group of test recording power values, including selected at least at least two values of test recording power; the step of calculating the first gradient to build the first straight line based on all the values of the test recording power included in the first group of test recording power values and the products corresponding to all the values of test recording power included in the first group of test recording power values and calculating the first gradient of the first straight line; the step of setting a second test recording power value, with respect to the first value, selecting at least two test recording values that are not completely the same as at least two test recording power values included in the first group of test recording power values from the plurality test recording power values and setting a second group of test recording power values including at least two selected test recording power values; a second gradient calculation step for constructing a second straight line based on all test recording power values included in the second group of test recording power values and products corresponding to all test recording power values included in the second group of test recording power values and calculating the second gradient of the second straight line; the step of obtaining a first relationship to obtain a first relationship corresponding to the first value based on the first gradient and the second gradient; the step of setting a third group of test recording power values with respect to the second value, selecting at least two test recording power values from a plurality of test recording power values and setting a third group of test recording power values including at least two test recording power values selected ; a third gradient calculation step for creating a third straight line based on all test recording power values included in the third group of test recording power values and products corresponding to all test recording power values included in the third group of test recording power values and calculating the third gradient of the third straight line; the step of setting a fourth group of test recording power values in relation to the second value by selecting at least two test recording power values that are not completely the same as at least two test recording power values included in the third group of test recording power values, from a plurality of test recording power values, and setting a fourth group of test recording power values including at least two test recording power values selected; a fourth gradient calculation step for creating a fourth straight line based on all test recording power values included in the fourth group of test recording power values and products corresponding to all test recording power values included in the fourth group of test recording power and calculating the fourth gradient of the fourth straight line; the step of obtaining a second relationship to obtain a second relationship corresponding to the second value based on the third gradient and the fourth gradient; and a comparison step for comparing the first relationship and the second relationship.

In one embodiment, the step of setting the first group of test recording power values includes the step of selecting the two largest test recording power values from the plurality of test recording power values; the step of setting the second group of test recording power values includes the step of selecting the two smallest test recording power values from the plurality of test recording power values; the step of setting the third group of test recording power values includes the step of selecting the two largest test recording power values from the plurality of test recording power values; and the step of setting the fourth group of test recording power values includes the step of selecting the two smallest test recording power values from the plurality of test recording power values.

In one embodiment, the method for determining recording power further comprises the steps of calculating a first average power value indicating an average value of the entire set of test recording power values with respect to the first value; and calculating a second average power value indicating an average value of the entire set of test recording power values with respect to the second value. The step of setting the first group of test recording power values includes the step of selecting test recording power values to be included in the first group of test recording power values from the plurality of test recording power values, so that the average value of the test recording power included in the first group values of test recording power, is greater than the first average power; the step of setting a second group of test recording power values includes a step of selecting test recording power values to be included in the second group of test recording power values from the plurality of test recording power values, so that the average value of test recording power included in the second group values of test recording power, is less than the first average power; the step of setting a third group of test recording power values includes a step of selecting test recording power values to be included in the third group of test recording power values from the plurality of test recording power values, so that the average value of test recording power included in the third group of values test recording power is greater than the second average power; and the step of setting the fourth group of test recording power values includes a step of selecting test recording power values to be included in the fourth group of test recording power values from the plurality of test recording power values, so that the average value of the test recording power included in the fourth group values of the test recording power, is less than the second average power.

In one embodiment, the method for determining the recording power further comprises the step of recording one of a plurality of values that corresponds to the largest linearity value on the information storage medium.

In one embodiment, the information storage medium has identification information recorded thereon for identifying the information storage medium; and the method for determining the recording power further comprises the step of storing the identification information and one of the plurality of values, which corresponds to the largest linearity value and corresponds to the identification information, in the identification information storage section.

In one embodiment, the method for determining the recording power further comprises the step of reading the identification information recorded on the information storage medium. The step of obtaining the product includes a step of determining whether the read identification information is really the same as the identification information stored in the identification information storage section, and when the read identification information is determined to be the same as the identification information stored in the information storage section identification, use of the value corresponding to the identification information stored in the identification information storage section.

In one embodiment, the identification information includes data indicating a manufacturer or a batch of information storage medium.

The program according to the present invention causes the information recorder to perform the steps of the method for determining the recording power described above.

A recording power determining apparatus according to the present invention for determining a recording power of an optical beam used when a recording section is recording data on an information storage medium, comprises an input section for receiving a signal indicating a plurality of modulation coefficients corresponding to a plurality of test recording power values; a calculation section for calculating an nth power product of each of a plurality of test recording power values and a modulation coefficient corresponding thereto so as to obtain a plurality of products corresponding to a plurality of test recording power, calculating a first recording power based on a correlation between a plurality of test recording power and a plurality of products and calculating the recording power based on the first recording power, where n is an exponent and is a real number other than 1; and an output section for outputting a signal indicating a recording power calculated by the calculation section to the recording section.

In one embodiment, the calculation section constructs an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and calculates a first recording power at which the product is 0 on the approximated line.

In one embodiment, the exponent n is 2.

In one embodiment, the input section receives a signal indicating a Pind value, a ρ value, and a k value; the output section gives a signal indicating the values of the test recording power in the range from 0.9 to 1.1 from the Pind value, to the recording section; and the calculation section builds an approximated line indicating the correlation between the set of test recording power values and the set of products, calculates the first recording power at which the product is 0 on the approximated line, and calculates the product of the first recording power, (-1 / (k value) +2 ) and ρ values to calculate the recording power.

In one embodiment, the input section receives a signal indicating an exponent n; and the calculation section uses an exponent n.

In one embodiment, the computing section obtains a plurality of products corresponding to a plurality of test recording power values for each of a plurality of values provided as an exponent n, calculates a linearity of correlation between a plurality of test recording power values and a plurality of products for each of a plurality of values, to calculate the set of linearity values corresponding to the set of values, determines one of the set of values that corresponds to a large linearity value, and calculates a first recording power using a plurality of products corresponding to a plurality of test recording power values relating to one of a plurality of values that corresponds to the largest linearity value.

In one embodiment, the plurality of values includes a first value and a second value; and the first value is 2, and the second value is 3.

In one embodiment, the input section receives a signal indicating a Pind value, a ρ value, and a k value; the output section gives a signal indicating the values of the test recording power in the range from 0.9 to 1.1 from the Pind value, to the recording section; and the calculation section constructs an approximated line based on the correlation between the plurality of test recording power values and the plurality of products, and calculates a first recording power at which the product is 0 on the approximated line.

In one embodiment, in the case where the linearity, when the exponent n is 2, is higher than the linearity, when the exponent n is 3, the calculation section calculates the product of the first recording power (-1 / (value k) +2) and the value ρ; and in the case where the linearity, when the exponent n is 3, is higher than the linearity, when the exponent n is 2, the calculation section calculates the product of the first recording power, (3 × (value k) -2) / (2 × (value k ) -1) and the values of ρ.

In one embodiment, the plurality of values includes a first value and a second value; and the calculation section with respect to the first value selects at least two test recording power values from the plurality of test recording power values and sets a first group of test recording power values including the selected at least two test recording power values; creates a first straight line on the basis of all test recording power values included in the first group of test recording power values and products corresponding to all test recording power values included in the first group of test recording power values, and calculates a first gradient of the first straight line; in relation to the first value, selects at least two test recording power values that are not completely the same as the at least two test recording power values included in the first group of test recording power values from the plurality of test recording power values and sets a second group test recording power values including at least two test recording power values selected; creates a second straight line based on all test recording power values included in the second group of test recording power values and products corresponding to all test recording power values included in the second group of test recording power values, and calculates a second gradient of the second straight line; receives a first ratio corresponding to a first value based on a first gradient and a second gradient; in relation to the second value, selects at least two test recording power values from a plurality of test recording power values and sets a third group of test recording power values including at least two test recording power values selected; creates a third straight line on the basis of all test recording power values included in the third group of test recording power values and products corresponding to all test recording power values included in the third group of test recording power values, and calculates a third gradient of the third straight line; in relation to the second value - selects at least two test recording power values that are not completely the same as at least two test recording power values included in the third group of test recording power values from the plurality of test recording power values and sets the fourth a group of test recording power values including at least two test recording power values selected; creates (builds) a fourth straight line based on all values of test recording power included in the fourth group of test recording powers and products corresponding to all values of test recording power included in the fourth group of test recording powers, and calculates the fourth gradient of the fourth straight line ; receives a second ratio corresponding to the second value based on the third gradient and the fourth gradient; and compares the first relation and the second relation so as to determine one of the first value and the second value, which corresponds to a higher linearity value.

In one embodiment, the calculation section when setting the first group of test recording power values selects the two largest test recording power values from the plurality of test recording power values; when setting the second group of test recording power values, selects the two smallest test recording power values from a plurality of test recording power values; when setting the third group of test recording power values, selects the two largest values of test recording power from a plurality of test recording power values; and when setting the fourth group of test recording power values, selects the two smallest test recording power values from the plurality of test recording power values.

In one embodiment, the calculation section calculates a first average power indicating an average value of the entire set of test recording power values with respect to the first value; calculates a second average power indicating an average value of the entire set of test recording power values with respect to the second value; when setting the first group of test recording power values, selects the test recording power values that should be included in the first group of test recording power values from the set of test recording power, so that the average value of the test recording power included in the first group of test recording power is greater than the first average power; when setting the second group of test recording power values, selects the test recording power values that should be included in the second group of test recording power values from the set of test recording power values, so that the average value of the test recording power included in the second group of test recording power values is less than the first average power; when setting the third group of test recording power values, selects the test recording power values that should be included in the third group of test recording power values from the set of test recording power, so that the average value of test recording power included in the third group of test recording power is greater than the second average power; and when setting a fourth group of test recording power values, selects test recording power values to be included in a fourth group of test recording power values from a plurality of test recording power values, so that the average value of test recording power included in the fourth group of test power values recording, is less than the second average power.

In one embodiment, the output section outputs a signal to the recording section, so that the recording section writes one of a plurality of values, which corresponds to the largest linearity value, to the information storage medium.

An information recording apparatus according to the present invention comprises a recording section for recording data on an information storage medium using an optical beam; a reading section for reading data recorded on the information storage medium; and a recording power determining apparatus for determining a recording power of the optical beam used when the recording section writes data to the information storage medium. The recording section writes test data to the information storage medium with a plurality of test recording powers; the reading section reads the test data recorded on the information storage medium at each of the plurality of test recording power values, generates a signal and measures a signal modulation coefficient corresponding to each of the plurality of test recording power values; and the recording power determining apparatus calculates an nth power product of each of a plurality of test recording power values and a modulation coefficient corresponding thereto to obtain a plurality of products corresponding to a plurality of test recording power, calculates a first recording power based on a correlation between a plurality of test recording power and many products and calculates the recording power based on the first recording power, where n is an exponent and is a real number, tlichnym 1.

In one embodiment, the exponent n is 2; the information storage medium has a value of Pind, a value of ρ, and a value of k recorded thereon; the read section reads the Pind value, the ρ value, and the k value; a recording power determining device determines a range of a plurality of test recording power values to a range from 0.9 to 1.1 of a Pind value; and the recording power determining apparatus constructs an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, calculates a first recording power at which the product is 0 on the approximated line, and calculates a product of the first recording power, (-1 / (k value) +2) and the values of ρ.

In one embodiment, the recording section records test data so that a signal generated by the reading section includes a plurality of single-period signals.

In one embodiment, the recording section forms a plurality of marks and a plurality of gaps on the information storage medium by means of an optical beam that has been modulated; and the recording section forms a plurality of marks, so that the amplitude of the signal generated by the reading section is substantially the same as the amplitude of the longest mark of the plurality of marks formed on the information storage medium.

In one embodiment, the recording power determining apparatus obtains a plurality of products corresponding to a plurality of test recording powers for each of a plurality of values provided as an exponent n, calculates a linearity of correlation between a plurality of test recording powers and a plurality of works for each of a plurality values, so as to calculate the set of linearity values corresponding to this set of values, and determines one of the set of values which corresponds to the largest linearity value; and the recording section records one of a plurality of values, which corresponds to the largest linearity value, on the recording information medium.

In one embodiment, the recording power determining apparatus includes a memory for storing one of a plurality of values that corresponds to the largest linearity value.

In one embodiment, the information storage medium has identification information recorded thereon for identifying the information storage medium; a read section reads identification information; the memory includes an identification information storage section for storing identification information and one of a plurality of values that corresponds to the largest linearity value and corresponds to identification information; identification information and one of a plurality of values that corresponds to the largest linearity value and corresponds to identification information are stored in the identification information storage section; and the recording power determining apparatus reads identification information recorded on the information storage medium, determines whether the read identification information is really the same as the identification information stored in the identification information storage section, and when it is determined that the read identification information is the same as the identification information stored in the identification information storage section, a value corresponding to the identification information stored in sections for storing identification information.

In one embodiment, the identification information includes data indicating a manufacturer or a batch of information storage medium.

The information storage medium according to the present invention includes a region for storing an exponent n corresponding to a linearity value that is the highest of a plurality of linearity values, the highest linearity being obtained by: computing an nth degree product of each of a plurality of test recording power values and the modulation coefficient corresponding to it, thus obtaining a plurality of products corresponding to the plurality of test recording power values, and to obtain Ia linearity correlation values between the plurality of test recording powers and the plurality of products regarding each of a plurality of degree n metrics based on the plurality of test recording powers and the plurality of products corresponding to the plurality of test recording powers.

A method for determining a recording power according to the present invention for determining a recording power of an optical beam for recording data on an information storage medium, the information storage medium having a Mind value and a ρ value recorded thereon, comprises a step of reading a value for reading a value recorded on the information storage medium , including the step of reading the Mind value and the ρ value; the step of confirming the recording of test data on the information storage medium with a plurality of test recording power values, reading out the test data recorded for each of the plurality of test recording power, generating a signal, measuring a plurality of signal modulation coefficients corresponding to the plurality of test recording power, and confirming that the largest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and that the smallest modulation coefficient of many the set of modulation coefficients is less than the Mind value; a step of calculating a first recording power to calculate a value of a first recording power based on a plurality of test recording power values and a plurality of modulation coefficients; and a step of calculating the recording power to calculate the recording power based on the first recording power and the value of ρ.

In one embodiment, the confirmation step includes the steps of determining whether the largest modulation coefficient of the plurality of modulation coefficients is less than the Mind value, and when it is determined that the largest modulation coefficient of the plurality of modulation coefficients is less than the Mind value, re-recording the test data with a plurality of large values of the test recording power until it is measured that the modulation coefficient, which is greater than the Mind value; and determining whether the smallest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and when it is determined that the smallest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, the test data is re-recorded for a plurality of smaller test values recording power until it is measured that the modulation coefficient is less than the Mind value.

In one embodiment, the step of calculating the first recording power includes the steps of calculating the product of the nth power of each of the plurality of test recording powers and the modulation coefficient corresponding thereto, thereby obtaining a plurality of products corresponding to the plurality of test recording powers, where n is an indicator degrees and is a real number; and calculating a first recording power based on a correlation between a plurality of test recording power values and this plurality of products.

In one embodiment, the step of calculating the first recording power includes the step of constructing an approximated line indicating a correlation between the plurality of test recording powers and the plurality of products, and calculating a first recording power at which the product is 0 on the approximated line.

In one embodiment, the exponent n is 1.

In one embodiment, the information storage medium has a Pind value and a k value recorded thereon; the step of reading the value includes the step of reading the value of Pind and the value of k; the confirmation step includes the step of setting the range of the plurality of test recording powers to a range from 0.9 to 1.1 of the Pind value; the step of calculating the first recording power includes the step of constructing an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and calculating a first recording power at which the product is 0 on the approximated line; and the step of calculating the recording power includes a step of calculating a product of the first recording power, the value of k, and the value of ρ.

In one embodiment, the exponent n is 2.

In one embodiment, the information storage medium has a Pind value and a k value recorded thereon; the step of reading the value includes the step of reading the value of Pind and the value of k; the confirmation step includes the step of setting the range of the plurality of test recording powers to a range from 0.9 to 1.1 of the Pind value; the step of calculating the first recording power includes the step of constructing an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and calculating a first recording power at which the product is 0 on the approximated line; and the step of calculating the recording power includes the step of calculating the product of the first recording power, (-1 / (value k) +2) and the value ρ.

In one embodiment, the confirmation step includes the steps of calculating a predetermined recording power at which the modulation factor is a Mind value; and setting a range of a plurality of test recording powers so that the smallest test recording power among a plurality of test recording powers is greater than a product of 0.9 by a predetermined recording power.

In one embodiment, the confirmation step includes the steps of calculating a predetermined recording power at which the modulation factor is a Mind value; and setting a range of a plurality of test recording powers so that the largest test recording power among a plurality of test recording powers is less than a product 1.1 by a predetermined recording power.

In one embodiment, the confirmation step includes the step of recording test data so that the generated signal includes a plurality of one-period signals.

In one embodiment, the information storage medium has a plurality of marks and a plurality of spaces formed by an optical beam that has been modulated; and the confirmation step includes the step of generating a plurality of marks, so that the amplitude of the generated signal is substantially the same as the amplitude of the longest mark of the plurality of marks formed on the information storage medium.

In one embodiment, the information storage medium has a plurality of tracks formed concentrically or helically thereon.

The program according to the present invention causes the information recorder to perform the steps of the method for determining the recording power described above.

The recording power determining apparatus according to the present invention for determining a recording power of an optical beam used when a recording section is recording data on an information storage medium, comprises an input section for receiving a signal indicating a plurality of modulation coefficients corresponding to a plurality of test recording powers, a Mind value and a value ρ; a calculation section for confirming that the largest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and that the smallest modulation coefficient of the plurality of modulation coefficients is smaller than the Mind value, calculating the first recording power based on the plurality of test recording power values and a plurality of modulation coefficients and calculating a recording power value based on a first recording power value and a ρ value; and an output section for outputting to the recording section a signal indicating the recording power calculated by the calculation section.

In one embodiment, the calculation section calculates the product of the nth power of each of the plurality of test recording powers and the modulation coefficient corresponding to it to obtain a plurality of products corresponding to the plurality of test recording powers, where n is a power exponent and is a real number; calculates a first recording power based on a correlation between a plurality of test recording powers and a plurality of products, and calculates a product of a first recording power and a ρ value.

In one embodiment, the calculation section constructs an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and calculates a first recording power at which the product is 0 on the approximated line.

In one embodiment, the exponent n is 1; the input section takes the value Pind and the value k; the output section gives a signal indicating the value of the test recording power in the range from 0.9 to 1.1 of the Pind value, to the recording section; and the calculation section constructs an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, calculates a first recording power at which the product is 0 on the approximated line, and calculates a product of the first recording power, k value, and ρ value.

In one embodiment, the exponent n is 2; the input section takes the value Pind and the value k; the output section provides a signal to the recording section indicating the value of the test recording power in the range from 0.9 to 1.1 of the Pind value; and the calculation section builds an approximated line indicating the correlation between the set of test recording power values and the set of products, calculates the first recording power at which the product is 0 on the approximated line, and calculates the product of the first recording power, (-1 / (k value) +2 ) and the values of ρ.

In one embodiment, the calculation section calculates a predetermined recording power at which the modulation coefficient is the Mind value, and sets a plurality of test recording powers so that the smallest test recording power from the plurality of test recording powers is greater than a product of 0.9 at a predetermined recording power; and the output section gives a signal indicating the set of test recording power values to the recording section.

In one embodiment, the calculation section calculates a predetermined recording power at which the modulation coefficient is a Mind value and sets the set of test recording powers so that the largest test recording power from the set of test recording powers is less than the product 1,1 at a predetermined recording power; and the output section provides a signal indicating the set plurality of test recording power to the recording section.

An information recording apparatus according to the present invention comprises a recording section for recording data on an information storage medium using an optical beam; a reading section for reading data recorded on the information storage medium; and a recording power determining apparatus for determining a recording power for the optical beam used when the recording section writes data to the information storage medium. The information storage medium has a Mind value and a ρ value recorded thereon; the reading section reads the Mind value and the ρ value; the recording section records test data on the information storage medium with a plurality of test recording powers; the reading section reads the test data recorded on the information storage medium at each of the plurality of test recording power values, generates a signal and measures a plurality of signal modulation coefficients corresponding to the plurality of test recording power values; and the recording power determining apparatus confirms that the largest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and that the smallest modulation coefficient of the plurality of modulation coefficients is smaller than the Mind value, calculates the first recording power based on the plurality of test power values recording and the set of modulation coefficients and calculates the recording power based on the first recording power and the value of ρ.

In one embodiment, the recording power determining apparatus determines whether the largest modulation coefficient of the plurality of modulation coefficients is less than the Mind value, and when the largest modulation coefficient of the plurality of modulation coefficients is determined to be smaller than the Mind value, determines the plurality of large values test recording power until the read section measures a modulation coefficient that is greater than the Mind value; and the recording power determining apparatus determines whether the smallest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and when the smallest modulation coefficient of the plurality of modulation coefficients is determined to be larger than the Mind value, determines the plurality of lower test recording power values until the read section measures that the modulation coefficient is less than the Mind value.

In one embodiment, the recording power determination apparatus calculates an nth power product of each of a plurality of test recording powers and a modulation coefficient corresponding thereto to obtain a plurality of products corresponding to a plurality of test recording powers, where n is an exponent and is a real number; calculates a first recording power based on a correlation between a plurality of test recording powers and a plurality of products, and calculates a product of a first recording power and a ρ value.

In one embodiment, the exponent n is 1; the information storage medium has a value of Pind and a value of k recorded thereon; the read section reads the value of Pind and the value of k; and the recording power determining device sets the range of the set of test recording powers to the range from 0.9 to 1.1 of the Pind value, builds an approximate line indicating the correlation between the set of test recording powers and the set of products, calculates the first recording power at which the product equals 0 on the approximated line, and calculates the product of the first recording power, the value of k, and the value of ρ.

In one embodiment, the exponent n is 2; the information storage medium has a value of Pind and a value of k recorded thereon; the read section reads the value of Pind and the value of k; the recording power determining device sets the range of the set of test recording powers to the range from 0.9 to 1.1 of the Pind value, builds an approximate line indicating the correlation between the set of test recording powers and the set of products, calculates the first recording power at which the product is equal to 0 on the approximated line, and calculates the product of the first recording power, (-1 / (k value) +2) and ρ value.

In one embodiment, the recording power determining apparatus calculates a predetermined recording power at which the modulation coefficient is a Mind value and sets a range of a plurality of test recording powers so that the smallest test recording power among a plurality of test recording powers is greater than 0, 9 from a predetermined recording power.

In one embodiment, the recording power determining apparatus calculates a predetermined recording power at which the modulation factor is a Mind value and sets a range of a plurality of test recording powers so that the largest test recording power among a plurality of test recording powers is less than 1, 1 from a predetermined recording power.

In one embodiment, the recording section records test data so that the signal generated by the reading section includes a plurality of single-period signals.

In one embodiment, the recording section forms a plurality of marks and a plurality of gaps on the information storage medium by means of an optical beam that has been modulated; and the recording section forms a plurality of marks so that the amplitude of the signal generated by the reading section is substantially the same as the amplitude of the longest mark of the plurality of marks formed on the information storage medium.

Result of invention

According to the recording power determination method and the recording power determination apparatus according to the present invention, a suitable recording power can be determined, and thus data can be properly recorded. In addition, unnecessarily rapid deterioration of the information storage medium can be prevented.

According to the program of the present invention, a suitable recording power can be determined, and thus data can be properly recorded. In addition, unnecessarily rapid deterioration of the information storage medium can be prevented.

According to an information recording apparatus according to the present invention, a suitable recording power can be determined, and thus data can be properly recorded. In addition, unnecessarily rapid deterioration of the information storage medium can be prevented.

According to the information recording apparatus of the present invention, each value corresponding to the largest linearity value of the plurality of values is recorded on the information storage medium as the exponent is read. Using this value, a suitable recording power can be determined quickly without the need for comparisons regarding linearity.

Brief Description of the Drawings

1 is a schematic diagram showing an optical disc of the present invention.

FIG. 2 is a schematic diagram showing an embodiment of an optical disc device according to the present invention.

FIG. 3 is a schematic diagram for describing a relationship between a binary waveform and a pulse waveform for marking according to the present invention.

4 is a schematic diagram showing an embodiment of a reproducing section in an optical disc device according to the present invention.

5 is a schematic diagram showing an embodiment of a recording power determining apparatus in an optical disk device according to the present invention.

6 is a flowchart for describing a first embodiment of a method for determining recording power according to the present invention.

7 is a schematic diagram for describing a recording of test data performed on an optical disc with a plurality of test recording powers in a first embodiment of a method for determining recording power according to the present invention.

FIG. 8 is a view for describing a first embodiment of a method for determining recording power according to the present invention, wherein FIG. 8 (a) is a graph illustrating a relationship between a test recording power and a modulation coefficient, and FIG. 8 (b) is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the square of the value of the test recording power.

FIG. 9 is a view for describing the influence of tilt in a first embodiment of a method for determining recording power according to the present invention, wherein FIG. 9 (a) is a graph illustrating the relationship between recording power and modulation coefficient, and FIG. 9 (b) is a graph, illustrating the relationship between (i) the recording power and (ii) the product of the modulation coefficient and the square of the recording power.

10 is a view for describing a first embodiment of a method for determining recording power according to the present invention, and is a graph illustrating a relationship between a test recording power and a modulation coefficient.

11 is a view for describing a first embodiment of a method for determining recording power according to the present invention, and is a graph illustrating the relationship between (i) a value of a test recording power and (ii) a product of a modulation coefficient and a test recording power.

FIG. 12 is a view for describing the effect of tilt in a second embodiment of a method for determining recording power according to the present invention, wherein FIG. 12 (a) is a graph illustrating a relationship between a test recording power and a modulation coefficient; FIG. 12 (b) is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the square of the test recording power, and FIG. 12 (c) is a graph illustrating the relationship between (i) the test power Strongly recording and (ii) the product of the modulation factor and the cube of the test recording power.

13 is a flowchart for describing a third embodiment of a method for determining recording power according to the present invention.

FIG. 14 is a view for describing a third embodiment of a method for determining recording power according to the present invention, in which FIG. 14 (a) is a graph illustrating a relationship between a test recording power and a modulation coefficient, and FIG. 14 (b) is a graph, illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the square of the value of the test recording power.

FIG. 15 is a view for describing a fourth embodiment of a method for determining recording power according to the present invention, wherein FIG. 15 (a) is a graph illustrating the relationship between the test recording power and the modulation coefficient, and FIG. 15 (b) is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power.

Fig. 16 is a schematic diagram showing a conventional optical disc.

17 is a schematic diagram showing a conventional optical disk device.

Fig. 18 is a schematic diagram showing a reproducing section in a conventional optical disc device.

Fig. 19 is a schematic diagram for describing a modulation coefficient.

FIG. 20 is a schematic diagram for describing a recording of test data performed on an optical disc with a plurality of test recording powers in a conventional manner for determining recording power.

21 is a view for describing a first conventional method for determining recording power, and is a graph illustrating a relationship between a test recording power value and a modulation coefficient.

22 is a view for describing a second conventional method for determining recording power and is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power.

23 is a view for describing the influence of tilt according to a first conventional method for determining recording power, and is a graph illustrating the relationship between the recording power and the modulation coefficient.

24 is a view for describing a second conventional method for determining recording power and is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power.

Description of Reference Positions

100 Optical Disk Device

101 Optical Disc

102 Optical head

104 Playback Section

106 Demodulation scheme / ECC

108 Recording power determination device

110 Recording Power Setting Section

112 Laser control circuit

114 Recording Data Generation Section

210 Recording Section

220 Reading Section

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1)

Below, embodiment 1 of a recording power determination method and a recording power determination apparatus according to the present invention is described with reference to FIGS.

1 is a schematic diagram showing an optical disc 101 in this embodiment. The optical disk 101 has a track 301 formed on it in a spiral. Irradiating the track 301 with an optical beam having a variable recording power, a plurality of marks and a plurality of gaps are formed on the track 301. In this way, data is recorded. The optical disc 101 includes a user data area used to record data by the user, and a recording power determination area used to determine the recording power of the optical beam. A recording power determination area is provided in a region other than the user data area (in particular, the innermost region or the most remote region of the optical disc 101).

FIG. 2 is a schematic diagram showing an optical disk device 100 including a recording power determining apparatus 108 according to this embodiment. The optical disk device 100 includes a recording section 210 for recording data on the optical disk 101 using an optical beam, a reading section 220 for reading data recorded on the optical disk 101, a recording power determining device 108 for determining an optical beam recording power used when the recording section 210 writes data to the optical disc 101, and the demodulation / ECC circuit 106 (error correction code). The recording section 210 includes an optical head 102, a recording power setting section 110, a laser control circuit 112, and a recording data generation section 114. The reading section 220 includes an optical head 102 and a reproducing section 104.

When the optical disk 101 is mounted on the optical disk device 100, the type of the optical disk 101 is identified, and the optical disk 101 rotates. The optical head 102 has a semiconductor laser (not shown). During rotation, the optical disk 101 is illuminated by an optical beam emitted from the semiconductor laser of the optical head 102.

To write data to the optical disk 101, the optical head 102 illuminates the optical disk 101 with an optical beam having a predetermined recording power to form a mark on the optical disk 101. In this example, the data of the modulation system with recording length limitation (1.7) is recorded by the edge recording method tags. In this case, seven types of marks and spaces are formed on the optical disk 101 based on the reference cycle T, which is 2T at least and 8T at most.

To read data from the optical disk 101, the optical head 102 illuminates the optical disk 101 with an optical beam having a reproduction power that is less than the recording power, and receives the light reflected by the optical disk 101. The optical head 102 performs optical / electrical conversion of the received light so that generate a signal indicating the data recorded on the optical disk 101.

Figure 3 depicts a schematic view for describing the relationship between the shape of the binary signal and the shape of the pulse for the formation of labels. FIG. 3 shows a binary waveform corresponding to a 2T mark, and a pulse waveform to form a 2T mark, a binary waveform corresponding to a 3T mark, and a pulse waveform to form a 3T mark, and a binary waveform corresponding to a 4T mark, and a pulse waveform to generate 4T tags.

The recording power parameters are peak power (Pp), bias power (Pe), and lower power value (Pbw). In this embodiment, the relationship between peak power, bias power, and lower power value is constant. As shown in FIG. 3, the number of pulses indicating Pp is one for the 2T tag and two for the 3T tag and increases by one with the tag length T increasing by one T.

The time-related waveform parameters are Ttop, dTtop, Tmp, and dTe. 3, Ttop represents the length of time during which the first pulse indicates Pp, and dTop represents the length of time between the time 1T after the rising edge of the binary signal and the rising time of the first pulse. Tmp represents the length of time during which pulses other than the first pulse indicate Pp, and dTe represents the length of time between the decay time of the binary edge and the time during which the last pulse increases from Pbw to Pe.

In this embodiment, peak power (Pp), bias power (Pe), lower power value (Pbw) are common to all labels (2T-8T). Tmp is also common to all tags. Ttop, dTtop and dTe are set to be classified into three classes 2T, 3T and 4T or more.

Returning to FIG. 2, the reproducing section 104 in the optical disk device 100 measures the modulation coefficient of the signal generated by the optical head 102 and digitizes the signal generated by the optical head 102. The demodulation / ECC circuit 106 demodulates the signal digitized by the reproducing section 104 and corrects the errors. The recording power determining apparatus 108 determines a recording power for recording data based on a modulation coefficient measured by the reproducing section 104. The recording power setting section 110 sets the recording power determined by the recording power determining apparatus 108 in the laser control circuit 112. The recording data generating section 114 generates data to be recorded on the optical disk 101. The laser control circuit 112 controls the optical head 102 to write data generated by the recording data generating section 114 to the optical disk 101 at a recording power set by the recording power setting section 110 .

FIG. 4 is a schematic diagram showing a reproducing section 104 in the optical disc device 100 of this embodiment. As shown in FIG. 4, the reproducing section 104 includes a pre-amplifier 201, a sampling and storage circuit (STX) 202, an analog-to-digital converter 203, an arithmetic operator 204 (an arithmetic operator unit), and a binary data generating section 205.

The binary data generating section 205 digitizes the signal generated by the optical head 102 to generate digitized data (binary data), and provides a binary data indicating signal 105 to the demodulation / ECC circuit 106 and the recording power determining device 108.

The pre-amplifier 201 amplifies the signal generated by the optical head 102. The sampling and storage circuit 202 selects a signal amplified by the pre-amplifier 201 and stores the peak value and the lower value of the signal. A / D converter 203 digitizes the peak value and the lower value stored by the sample and store circuit 202. The arithmetic operator 204 performs an arithmetic operation on the digitized peak value and the lower value to obtain a modulation coefficient, and provides a signal 107 indicating the modulation coefficient to the recording power determining device 108.

5 is a schematic diagram showing a recording power determination apparatus 108 according to this embodiment. As shown in FIG. 5, the recording power determining apparatus 108 includes an input section 401 for receiving a signal 107 indicating a modulation factor, a calculation section 402 for calculating an optical beam recording power used when the recording section 210 writes data to the optical disc 101, an output section 403 for outputting the calculated recording power to a recording power setting section 110 in the recording section 210 and a memory 404.

A method for determining recording power according to this embodiment will be described below with reference to FIG. 6.

A constant parameter is recorded on the optical disc 101, which should be used to determine the recording power. As shown in step S12 in FIG. 6, the optical head 102 generates a signal 103 indicating a constant parameter (hereinafter referred to as a “predetermined value”) read from the optical disk 101, and outputs the signal 103 to the reproducing section 104. The binary data generating section 205 in the reproducing section 104 generates a binary signal 105 obtained by binarizing the signal 103 indicating a predetermined value, and provides a signal 105 to the recording power determining device 108.

As shown in step S14 in FIG. 6, test data is recorded on the optical disc 101 at a plurality of test recording powers. To record the test data, the recording power determining device 108 provides a signal 109 indicating eight predetermined eight different values of the test recording power A to H to the recording power setting section 110. The recording power setting section 110 sets the test recording power AH values in the laser control circuit 112. In this example, the test recording power value A is the largest power, and the test recording power becomes smaller from the test recording power value B to the test power value H.

The recording data generating section 114 generates test data and provides a signal 115 indicating the generated test data to the laser control circuit 112. The laser control circuit 112 controls the optical head 102 to record test data substantially one revolution of the track continuously from a predetermined position in the recording power determination area of the optical disc 101. The recording data generating section 114 generates test data so that the optical head 102 continuously forms 8T marks and gaps 8T on the optical disc 101. Test data is repeatedly recorded on essentially one revolution of the optical disc 101 at A-H test recording powers. Fig.7 depicts the area of the optical disk 101 corresponding to the values aH test recording power, with the characters "A" - "H". By recording data on essentially one revolution of the optical disk 101 in a plurality of repetitive ways, the influence of tilts dispersed in the direction of the periphery of the optical disk 101 can be eliminated.

Returning to FIG. 6, when the test data recording is completed, as shown in step S16 in FIG. 6, the optical head 102 illuminates the optical disk 101 with an optical beam having a reproduction power. As a result, the test data recorded on the track of the optical disc 101 is read, and a signal is generated indicating the test data. The amplitude of the signal generated by the optical head 102 varies according to whether marks are actually formed on the optical disk 101. The signal 103 generated by the optical head 102 is supplied to the reproducing section 104.

As shown in FIG. 3, the pre-amplifier 201 of the reproducing section 104 amplifies the signal 103. The sample and store circuit 202 stores the peak value and the lower value of the signal amplified by the pre-amplifier 201. The analog-to-digital converter 203 digitizes the peak value and the lower signal value stored by the circuit 202 sampling and storage. The arithmetic operator 204 performs an arithmetic operation on the digitized peak value and the lower value to obtain a modulation coefficient of the signal. Since the amplitude of the signal 703 is different according to the values A – H of the test recording power, the modulation coefficient also differs according to the values A – H of the test recording power. The arithmetic operator 204 generates a signal 107 indicating the modulation factor of the signal, and provides a signal 107 to the recording power determining device 108.

As shown in FIG. 5, a signal 107 indicating a modulation coefficient corresponding to each A-H test recording power is input to an input section 401 of a recording power determining apparatus 108 from an arithmetic operator 204 in a reproducing section 104.

As shown in step S18 in FIG. 6, the calculation section 402 in the recording power determination apparatus 108 calculates a product of the modulation coefficient corresponding to the test recording power and the square of the test recording power A. Section 402 of the calculation also calculates the product of the modulation coefficient corresponding to each of the values BN of the test recording power and the square of each value BH of the test recording power. Thus, the calculation section 402 obtains a plurality of products corresponding to the test recording power A-H values.

Then, as shown in step S20 in FIG. 6, the calculation section 402 calculates the first recording power based on the correlation between the plurality of test recording power AH values and the plurality of products. In particular, the calculation section 402 constructs an approximated line indicating a correlation between the plurality of test recording power values and the plurality of products, and sets the recording power at which the product is 0 on the approximated line as the first recording power. This will be described in more detail below with reference to FIG.

Fig. 8 (a) is a graph illustrating the relationship between the test recording power and the modulation coefficient corresponding to the test recording power. Fig. 8 (b) is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the square of the value of the test recording power. As is clear from FIGS. 8 (a) and 8 (b), the linearity of the correlation between the test recording power and the modulation coefficient is low, while the linearity of the correlation between (i) the test recording power and (ii) the product of the modulation coefficient and squared test recording power is high. In the graph of FIG. 8 (b), eight points corresponding to A-H values of the test recording power are arranged in a substantially straight line.

The calculation section 402 calculates the recording power P500 at which the product of the modulation coefficient and the squared value of the test recording power is 0 on the approximated line shown in the graph of FIG. 8 (b).

Then, as shown in step S22 of FIG. 6, the calculation section 402 calculates the recording power based on the recording power P500. In particular, the calculating section 402 performs an arithmetic operation on the recording power P500 and the predetermined value recorded on the optical disc 101 to calculate the recording power.

The output section 403 outputs a signal 109 indicating the recording power calculated by the calculation section 402 to the recording power setting section 110.

The program may be used such that a central processing unit CPU (not shown) controls the elements of the optical disk device 100 in accordance with the above procedure. The program may be stored on a computer-readable recording medium (not shown) such as EPROM, ROM, RAM, a hard disk drive, a magnetic recording medium, or the like.

Below with reference to Fig.9 describes the relationship between the recording power and the modulation coefficient in the case when there is a relative slope between the optical disk 101 and the optical head 102.

Fig. 9 (a) is a graph illustrating the relationship between the recording power and the modulation coefficient corresponding to the recording power, and is similar to Fig. 23. In the graph of FIG. 9 (a), solid line 1201A represents the result obtained when there is no slope during data recording or while reading recorded data. The solid line 1202A represents the result obtained when there is a slope during data recording, but there is no slope during data reading. The solid line 1203A represents the result obtained when there is a slope both during data recording and during data reading. The modulation coefficient is lower when there is a slope than in the case when there is no slope. In the case where there is no slope during data reading, but there is a slope during data recording, the modulation coefficient corresponding to the value H of the test recording power, which is the smallest among the eight values of the test recording power, cannot be measured. Similarly, in the case where there is a slope both during data recording and during data reading, the modulation coefficient corresponding to the value H of the test recording power cannot be measured.

Fig. 9 (b) is a graph illustrating the relationship between (i) the recording power shown in Fig. 9 (a) and (ii) the product of the modulation coefficient shown in Fig. 9 (a) and the square of the recording power. In the graph of FIG. 9 (b), solid line 1201B represents the result obtained when there is no slope during data recording or while reading recorded data. Solid line 1202B represents the result obtained when there is a slope during data recording, but there is no slope during data reading. The solid line 1203B represents the result obtained when there is a slope both during data recording and during data reading.

As described above, test data is written and read before user data is written. Test data is read immediately after recording. Accordingly, when the test data is recorded and read while there is a relative slope, the results are represented by solid lines 1203A and 1203B.

According to this embodiment, as shown in FIG. 9 (b), the recording power determining apparatus 108 calculates a recording power P1203 at which the product of the modulation coefficient and the square of the test recording power is 0, calculates the recording power based on the recording power P1203 and a predetermined a value recorded on the optical disc 101, and outputs a signal 109 indicating the calculated recording power to the recording power setting section 110.

The result represented by the solid line 1203B is obtained under the influence of tilt during recording and also tilt during reading. As described above, to determine the recording power, only the effect of the tilt during recording should be considered. Therefore, the recording power to be selected at this moment is essentially the recording power P1202, but it has been experimentally confirmed that the recording power P1203 selected by the recording power determination method of this embodiment is generally equal to the recording power P1202 to be selected as shown in Fig. 9 (b).

Namely, the recording power, at which the product of the modulation coefficient and the square of the recording power is 0, is the critical recording power necessary for forming marks on the optical disk 101. When recording power is used that is greater than the critical recording power, a modulation coefficient that is not 0, measured whether or not there is a slope during reading. Therefore, the recording power at which the product of the modulation coefficient and the square of the recording power is 0 is the same regardless of whether there is a slope during reading or not.

As described above, according to this embodiment, even when there is a relative tilt between the optical disk and the optical head, the corresponding recording power can be determined, and thus the data can be recorded properly. According to this embodiment, deterioration of the optical disc is prevented unnecessarily quickly by re-recording.

According to this embodiment, a suitable recording power can be determined for any exposure that degrades the modulation factor both during recording and during playback, not limited to tilt.

This embodiment is particularly effective for an optical disc device conforming to the BD format (Blu-ray disc), which requires more precise adjustment of the recording power for a higher recording density.

Disc manufacturers that produce optical discs that conform to the BD format determine in advance the Pwo recording power, which is recommended for writing data to an optical disc, before shipping the optical discs. The write power Pwo is determined such that when an ideal optical disk device writes data to an ideal optical disk with a write power Pwo and then reads data, the corresponding modulation factor is measured. However, due to individual differences among real optical disks and optical disk devices, even when an optical disk device writes data at a recording power Pwo, a suitable modulation factor is not necessarily measured when data is read.

Accordingly, to write data to an optical disc, the optical disc device determines a suitable recording power after checking the relationship between each of the plurality of test recording power values and the modulation coefficient corresponding thereto. Disc manufacturers pre-store the constant parameters used to determine the appropriate recording power on the optical disc. These constant parameters are Pind, ρ, k and Mind. Although described in more detail below, a suitable recording power for recording data on an optical disc is obtained using the recording power Pind, which is less than the recording power Pwo, and the relationship between the recording power Pind and the modulation factor Mind. It is not recommended to directly determine the recording power Pwo for the following reasons: (1) since the modulation coefficient reaches saturation near the recording power Pwo, it is difficult to detect a change in the optimal recording power caused by external disturbances such as tilt or the like, as described above with reference to Fig.9; and (2) re-determining the recording power leads to deterioration of the optical disc 101.

Below, with reference to FIGS. 10 and 11, the relationship between the recording power Pwo recommended by the optical disc manufacturers Pind, ρ, k and Mind is described.

Disc manufacturers determine the recording power Pwo, then determine the recording power Pind and determine ρ based on the relation ρ = recording power Pwo / recording power Pind.

As shown in FIG. 10, disc manufacturers read data recorded at the recording power Pind to form 8T marks and set the modification coefficient of the signal corresponding to the data as the modification coefficient Mind.

As shown in FIG. 11, disc manufacturers read test data recorded at a plurality of test recording powers within a range of 0.9 to 1.1 of the recording power Pind to form 8T marks, generate a signal, and measure a plurality of signal modulation coefficients. A plurality of modulation coefficients respectively corresponds to a plurality of test recording powers.

Disc manufacturers compute the product of each test recording power and the modulation coefficient corresponding thereto, and calculate the recording power Pthr based on the correlation between the plurality of test recording powers and the plurality of products. In particular, an approximate line is constructed that indicates the correlation between the set of test recording power values and the set of products, and the recording power at which the product is 0 on the approximated line is set as the recording power Pthr. Then, a value of k is determined based on the relation k = recording power Pind / recording power Pthr.

Disc manufacturers pre-store the Pind value, the ρ value, the k value, and the Mind value on the optical disk 101.

In this embodiment, the value corresponding to the recording power Pthr at which the modulation coefficient is 0 is calculated based on the relationship between the test recording power and the modulation coefficient, the recording power (i.e., the value corresponding to Pind) is calculated based on the recording power Pthr and the value k, and the recording power Pw is calculated based on the value of the calculated recording power and the value ρ.

The following describes a method for determining the recording power according to this embodiment in the case where the optical disc conforms to the BD format.

The playback section 104 reads the value of k and the value of ρ recorded on the optical disc 101, and provides a signal 105 indicating the value of k and the value of ρ to the recording power determining device 108.

After the recording section 210 of the optical disc device 100 records test data at test recording power values A-H, the reproducing section 104 measures a plurality of modulation coefficients corresponding to this plurality of test recording power values. The playback section 104 outputs a signal 107 indicating a plurality of modulation coefficients corresponding to a plurality of test recording power values to a recording power determining apparatus 108.

When the result, as shown in FIG. 8 (a), is obtained by reading the test data, the recording power determining device 108 calculates the recording power P500 at which the product of the modulation coefficient and the square of the recording power is 0, as shown in FIG. 8 (b) , and calculates the recording power Pw1 for recording data in accordance with the following expression 1.

Pw1 = P500 × (-1 / k + 2) × ρ Expression 1

The recording power determining device 108 provides a signal 109 indicating the calculated recording power Pw1 to the recording power setting section 110.

As described above, according to this embodiment, since the linearity of the correlation between (i) the test recording power value and (ii) the product of the modulation coefficient and the square of the test recording power value is high, the corresponding recording power can be determined without relying on the range test recording power.

In the above description, the first recording power (P500) is calculated using the product of the modulation coefficient and the square of the test recording power, that is, the product for the case where the exponent n of the test recording power is 2. The present invention is not limited to this. Depending on the structure of the optical disc or the characteristics of the recording film of the optical disc, the linearity of correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the nth degree of the test recording power can be high in the case when the exponent n is not equal to 2 Accordingly, the exponent n is not limited to 2.

It should be noted that, as described above with reference to FIG. 22, such linearity when the exponent is 1, that is, the linearity of the correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power, is low . In the graph of FIG. 22, the points plotted on the graph are not in a straight line.

Accordingly, the value of exponent n is any real number other than 1. The experiments were performed on the value of exponent n using several existing optical disks. When, for example, the exponent n is equal to from 1.5 to 2.5, the linearity of the correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the nth degree of the test recording power was high. However, the value of the exponent n of the degree is not limited to this and can be equal to 0.5, 0 or -1, for example.

According to this embodiment, the linearity of the correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the nth power of the test recording power can be made high. Therefore, the recording power at which the product of the modulation coefficient and the nth power of the test recording power is 0 can be calculated independently of the test recording power.

A suitable recording power P500 can be obtained without recording data at eight test recording values A-H, as shown in FIG. A suitable recording power P500 can be obtained by recording data at four recording values AD, four recording values E-H or four recording values C-F. When determining the recording power using a predetermined area width, the number of repetitions can be increased, and thus the accuracy of the recording power value to be determined can be increased, reducing the number of test recording power values.

Preferably, the value of exponent n is recorded on the optical disc 101. By recording the exponent n on the optical disc 101, the degree of freedom can be extended to design the structure of the optical disc device 101 or the recording film in the optical disc 101.

The recording power determination method of this embodiment is particularly effective for an optical disk device in which it is necessary to control the recording power with higher accuracy to obtain a higher recording density, for example, for an optical disk device corresponding to the BD format.

(Embodiment 2)

Embodiment 2 of a recording power determination method and a recording power determination apparatus according to the present invention will be described below with reference to FIG. 12.

The recording power determining apparatus 108 of this embodiment has substantially the same structure as the recording power determining apparatus described in Embodiment 1 with reference to FIG. 5. The optical disk device 100 including the recording power determining device 108 of this embodiment also has substantially the same structure as the structure in the optical disk device described in Embodiment 1 with reference to FIG. 2. In order to avoid redundancy, the recording power determining apparatus 108 and the optical disc apparatus 100 according to this embodiment are not described with respect to details that are the same as in Embodiment 1.

Unlike in embodiment 1, the recording power determination apparatus 108 according to this embodiment calculates the product of the modulation coefficient and the nth power of the test recording power with respect to each of the plurality of n power indicators, calculates the linearity of the correlation between (i) the test power of the recording and (ii ) by the product of the modulation coefficient and the nth power of the test recording power and determines the recording power using one of the many indicators of the n degree that corresponds to the largest value linearity.

The following describes a method for determining recording power when an exponent n is 2 and 3, with reference to FIGS. 2 and 5.

The playback section 104 outputs a signal 107 indicating a plurality of modulation coefficients corresponding to a plurality of test recording power values to a recording power determining apparatus 108. A signal 107 indicating modulation coefficients corresponding to the values of AH test recording power is supplied to the input section 401 of the input device 108 to determine the recording power from the arithmetic operator 204 in section 104 of the playback.

Section 402 of the calculation calculates the product of the modulation coefficient corresponding to the test recording power A and the square of the value A of the test recording power. Section 402 of the calculation calculates the product of the modulation coefficient corresponding to each of the values B-H test recording power and the square of each value B-H test recording power. Thus, the calculation section 402 obtains a plurality of products corresponding to the values A-H of the test recording power when the exponent n is equal to 2.

Section 402 of the calculation also calculates the product of the modulation coefficient corresponding to the test recording power A and the cube of the value A of the test recording power. Section 402 of the calculation calculates the product of the modulation coefficient corresponding to each value BN of the test recording power and the cube of each value BH of the test recording power. Thus, the calculation section 402 obtains a plurality of products corresponding to the values A-H of the test recording power, in the case when the exponent n is 3.

12 (a) is a graph illustrating a relationship between a test recording power value and a modulation coefficient corresponding to a test recording power. 12 (b) is a graph illustrating the relationship between (i) the test recording power value and (ii) the product of the modulation coefficient and the squared test recording power value. 12 (c) is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the cube of the value of the test recording power.

Section 402 of the calculation compares the linearity obtained when the exponent n of the degree equal to 2, and the linearity obtained when the exponent n of the degree equal to 3, and determines which linearity is higher. A comparison regarding linearity is described below. Here, when, for example, the linearity obtained when the exponent n is equal to 2 is higher than the linearity obtained when the exponent n is equal to 3, calculation section 402 calculates the recording power P500 based on the correlation between the plurality of test recording power A-H values and a plurality of products corresponding to them (calculated above) in the case where the value of the exponent n is 2. In particular, the calculation section 402 constructs an approximated line indicating a correlation between the plurality of test recording power values and the plurality products, and calculates a recording power P500 at which the product is 0 on the approximate line. Then, the calculation section 402 performs an arithmetic operation on the recording power value P500 and the predetermined value read from the optical disc 101 to calculate the recording power. The output section 403 outputs a signal 109 indicating the calculated recording power to the recording power setting section 110, and the recording power setting section 110 sets the recording power in the laser control circuit 112.

With reference to FIGS. 12 (b) and 12 (c), a comparison with respect to linearity is described.

When the exponent is 2, calculation section 402 calculates a linear correlation between (i) the test recording power and the product of the modulation coefficient and the square of the test recording power. For example, calculation section 402 selects the two largest of the test recording power A-H values (test recording power A and B values) and the two smallest test recording power values A-H (test recording power G and H values). With reference to the graph in FIG. 12 (b), calculation section 402 constructs a straight line connecting a point corresponding to a test recording power value A and a point corresponding to a test recording power value B (hereinafter, this straight line is referred to as a “first straight line” ), and computes the gradient of the first straight line (hereinafter referred to as the "first gradient"). Also, with reference to the graph in FIG. 12 (b), the calculation section 402 constructs a straight line connecting a point corresponding to a test recording power G and a corresponding point to a test recording power H (hereinafter, this straight line is called the “second straight line” ), and calculates the gradient of the second straight line (hereinafter referred to as the "second gradient"). Section 402 of the calculation calculates the relationship between the first gradient and the second gradient (hereinafter referred to as the "first ratio").

When the exponent is also equal to 3, calculation section 402 calculates a linear correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the cube of the test recording power. For example, calculation section 402 selects the two largest of the test recording power A-H values (test recording power A and B values) and the two smallest test recording power values A-H (test recording power G and H values). With reference to the graph in FIG. 12 (c), the calculation section 402 constructs a straight line connecting a point corresponding to a test recording power value A and a point corresponding to a test recording power value B (hereinafter, this straight line is referred to as a “third straight line” ), and computes the gradient of the third straight line (hereinafter referred to as the "third gradient"). Also, with reference to the graph in FIG. 12 (c), the calculation section 402 constructs a straight line connecting a point corresponding to a test recording power G value and a point corresponding to a test recording power value H (hereinafter, this straight line is referred to as a “fourth straight line” "), and computes the gradient of the fourth straight line (hereinafter referred to as the" fourth gradient "). Section 402 of the calculation calculates the relationship between the third gradient and the fourth gradient (hereinafter referred to as the "second ratio").

Then, the calculation section 402 compares the first ratio and the second ratio and determines that the linearity of the value for the value of the metric corresponding to one of the first ratio and the second ratio, which is closer to ratio 1, is higher. Then, as described above, the calculation section 402 calculates the recording power based on the correlation corresponding to the value of the indicator, providing a higher linearity. Since the calculation section 402 determines the recording power based on the correlation corresponding to the value of the indicator providing higher linearity, a more suitable recording power can be determined.

However, the method for comparison based on linearity is not limited to this. In the above description, the calculation section 402 compares the gradient near the maximum value of the plurality of test recording powers and the gradient near the minimum value of the plurality of test recording powers. Computing section 402 may use a different method, as described below, to compare a gradient near a maximum value and a gradient near a minimum value from a plurality of test recording power values.

When the exponent n is 2, the calculation section 402 calculates a first average power that indicates an average value of the whole set of test recording power values. Then, the calculation section 402 selects at least two test recording power values as test recording power values belonging to one group of test recording power values (hereinafter referred to as the “first group of test recording power values”) from the plurality of test recording power values. The test recording power values belonging to the first group of test recording power values are selected such that the average value of such test recording power values is larger than the first average power. Then, the calculation section 402 creates a first straight line indicating a correlation between test recording power values belonging to the first group of test recording power values and products corresponding to these test recording power values, and calculates a first gradient of the first straight line. Then, the calculation section 402 selects at least two test recording power values as test recording power values belonging to another group of test recording power values (hereinafter referred to as the “second group of test recording power values”) from the plurality of test recording power values. The test recording power values belonging to the second group of test recording power values are selected such that the average value of such test recording power values is less than the first average power. Then, the calculation section 402 constructs a second straight line indicating a correlation between the test recording power values belonging to the second group of test recording power values and the products corresponding to these test recording power values, and calculates a second gradient of the second straight line. Then, the calculation section 402 calculates a first ratio based on the first gradient and the second gradient.

When the exponent n is also equal to 3, the calculation section 402 calculates a second average power, which indicates the average value of the entire set of test recording power values. Then, the calculation section 402 selects at least two test recording power values as test recording power values belonging to one group of test recording power values (hereinafter referred to as the “third group of test recording power values”) from the plurality of test recording power values. The test recording power values belonging to the third group of test recording power values are selected so that the average value of such test recording power values is greater than the second average power. Then, the calculation section 402 constructs a third straight line indicating a correlation between the test recording power values belonging to the third group of test recording power values and the products corresponding to these test recording power values, and calculates a third gradient of the third straight line. Then, the calculation section 402 selects at least two test recording power values as test recording power values belonging to another group of test recording power values (hereinafter referred to as the “fourth group of test recording power values”) from the plurality of test recording power values. Test recording power values belonging to the fourth group of test recording power values are selected such that the average value of such test recording power values is less than the second average power. Then, the calculation section 402 constructs a fourth straight line indicating a correlation between test recording power values belonging to the fourth group of test recording power values and products corresponding to these test recording power values, and calculates a fourth gradient of the fourth straight line. Then, the calculation section 402 calculates a second ratio based on the third gradient and the fourth gradient.

Then, the calculation section 402 determines that the linearity of the value for the indicator value corresponding to one of the first ratio and the second ratio, which is closer to the ratio of 1, is higher.

As described above, from a plurality of indicators of degree n, a value providing a higher linearity can be selected.

The linear comparison method in this embodiment is not limited to the above. Computing section 402 may perform a linearity comparison as follows. For each of the plurality of n-degree indicators, the calculation section 402 sets one group of test recording power values including at least two test recording power values from the plurality of test recording power, another group of test recording power values including at least at least two values of test recording power from the set of values of test recording power, so the values of test recording power in these two groups of values of test recording power are not are the same. Then, calculation section 402 constructs a straight line for each group of test recording power values and calculates the gradient of each straight line. A linearity comparison can be made in this way.

In more detail, with respect to the value of indicator 2, the calculation section 402 selects at least two test recording power values from a plurality of test recording power values so as to establish a first group of test recording power values including at least two test recording power values selected . Then, the calculation section 402 builds (creates) a first straight line based on all the test recording power values of the first group of test recording power values and products corresponding to all test recording power values of the first group of test recording power values, and calculates a first gradient of the first straight line. Regarding the value of the metric 2, the calculation section 402 selects at least two test recording power values from the plurality of test recording power values so that these test recording power values are not completely the same as those included in the first group of test recording power values to establish a second group of test recording power values including at least two selected test recording power values. Then, the calculation section 402 creates (builds) a second straight line based on all the test recording power values of the second group of test recording power values and products corresponding to all the test recording power values of the second group of test recording power values, and calculates a second gradient of the second straight line. Then, the calculation section 402 calculates a first ratio based on the first gradient and the second gradient.

Regarding the value of the metric 3, the calculation section 402 also selects at least two test recording power values from the plurality of test recording power values to establish a third group of test recording power values including the selected at least two test recording power values. Then, the calculation section 402 creates (builds) a third straight line based on all the test recording power values of the third group of test recording power values and products corresponding to all test recording power values of the third group of test recording power values, and calculates a third gradient of the third straight line. Regarding the value of the indicator 3, the calculation section 402 selects at least two test recording power values from the plurality of test recording power values so that these test recording power values are not completely the same as those included in the third group of test recording power values to establish a fourth group of test recording power values including at least two selected test recording power values. Then, the calculation section 402 constructs a fourth straight line based on all the test recording power values of the fourth group of test recording power values and products corresponding to all test recording power values of the fourth group of test recording power values, and calculates the fourth gradient of the fourth straight line. Then, the calculation section 402 calculates a second ratio based on the third gradient and the fourth gradient.

Section 402 of the calculation compares the first ratio and the second ratio and thus determines that one of the first value and the second value, which corresponds to a higher linearity.

Above are many ways to compare. In any comparison method, when one ratio is equal to or greater than 1 and the other ratio is equal to or less than 1, calculation method 402 can calculate the reciprocal of the ratio that is equal to or greater than 1 to make both ratios equal or less than 1, and select a value that is closer to 1 in this state. Alternatively, when one ratio is equal to or greater than 1 and the other ratio is equal to or less than 1, the calculation method 402 may calculate an inverse value of the ratio that is equal to or less than 1 to make both ratios equal or greater than 1, and select a value closer to 1 in this condition.

The many ways described above for comparison with respect to linearity are just an example. Any method may be used as long as a comparison can be made with respect to linearity of correlation.

As described in Embodiment 1, when the exponent n is also equal to 3, the recording power at which the product of the modulation coefficient and the cube of the test recording power is 0 is the critical recording power for forming marks on the optical disk 101. When the recording power is greater than critical recording power, modulation coefficient is measured whether or not there is a slope during reading. Therefore, the write power at which the product of the modulation coefficient and the cube of write power is 0 is the same regardless of whether or not there is a slope during reading.

Recently, optical discs have been developed, including a plurality of recording films. In this embodiment, an exponent n can be appropriately determined for each of the plurality of values of the recording films of one optical disc.

In the recording power determining device 108 according to this embodiment, the output section 402 outputs a signal to the recording section 210 so that a value from the plurality of exponents n of the degree corresponding to the largest linearity value is recorded on the optical disc 101. The recording section 210 records such a degree exponent on an optical disc 101. The optical disc 101 may have an area for recording such a metric value in advance. Alternatively, such an exponent may be recorded in a user data area of the optical disc 101. In the case where such an exponent is recorded in a predetermined area of the optical disc 101, as described above, the optical disc device 100 having such an optical disc 101 installed therein reads the value recorded on the optical disc 101 to determine the recording power, and can determine the appropriate recording power by quickly using the read value without performing a comparison with respect to linearity.

Alternatively, such an exponent may be recorded on the optical disk device 100.

In this embodiment, the optical disc 101 has identification information recorded thereon for identifying the optical disc 101. The identification information is, for example, information regarding the disc manufacturer of the optical disc 101 or information regarding the batch of the optical disc 101.

The playback section 104 reads the identification information recorded on the optical disc 101, and provides a signal 105 indicating the identification information to the recording power determining apparatus 108.

A signal 105 indicating identification information is supplied to an input section 401 in the recording power determination apparatus 108. The memory 404 in the recording power determination apparatus 108 includes a storage section of identification information. After the index n of the highest linearity value corresponding to the identification information of the optical disk 101 is determined from the plurality of values, the calculation section 402 stores the identification information of the optical disk 101 and the value of the highest linearity corresponding to the identification information of the optical disk 101 in the identification information storage section in memory 404.

The identification information of the optical disk 101 and the highest linearity value corresponding to the identification information of the optical disk 101 are stored in the memory 404. Therefore, when the optical disk 101 is installed in the optical disk device 100, the reproducing section 104 reads the identification information of the installed optical disk 101, and the section 402 the calculation in the recording power determining device 108 determines whether the read identification information is really the same as the identification information, with wounded in the identification information storage section. If it is determined that the read identification information is the same as the identification information stored in the identification information storage section, the calculation section 402 reads out the exponent n corresponding to the highest linearity value from the plurality of values from the memory 404 and can determine a suitable recording power quickly using a read value without comparing over a plurality of values with respect to linearity.

This embodiment is particularly effective in an optical disc device conforming to the BD format, as in Embodiment 1.

As described in Embodiment 1, an optical disc corresponding to the BD format has a Pind value, a ρ value, a k value, and a Mind value previously stored on it. The playback section 104 reads the values of ρ and k.

When the calculation section 402 determines that the linearity obtained when the exponent n is 2 is higher, the calculation section 402 calculates the recording power P500 shown in FIG. 12 (b) and calculates the recording power Pw1 in accordance with the following expression 1.

Pw1 = P500 × (-1 / k + 2) × ρ Expression 1

Conversely, when the calculation section 402 determines that the linearity obtained when the exponent n is 3 is higher, the calculation section 402 calculates the recording power P600 shown in FIG. 12 (c) and calculates the recording power Pw1 in accordance with the following expression 2 .

Pw1 = P600 × (3k-2) / (2k-1) × ρ Expression 2

The output section 403 outputs a signal 109 indicating the recording power Pw1 to the recording power setting section 110.

In the above description, the exponent n is 2 and 3. Depending on the structure of the optical disc or the characteristics of the recording film of the optical disc, linearity can be high when the exponent n is neither 2 nor 3. In this embodiment, the exponent n is not limited a value of 2 or 3 and can be any real number other than 1. To calculate the recording power, the coefficients related to k and ρ are changed in accordance with the value of the exponent n. For example, when the exponent n is equal to 0, the calculating section 402 calculates the recording power Pw1 in accordance with the following expression 2 ′.

Pw1 = P700 × (1 / (2-k)) × ρ Expression 2 ′

Here, the P700 is obtained as follows. An approximated line indicating the correlation between the set of values of the test recording power and the set of products when the exponent n is equal to 0 is plotted and the recording power at which the product is 0 on the approximated line is P700.

In this regard, when the exponent n is equal to 1, the recording power Pw1 is calculated in accordance with the following expression, as described above with reference to FIG. 22.

Pw1 = Pthr × k × ρ

Pthr is prepared as follows. The approximated line indicating the correlation between the set of test recording power values and the set of products when the exponent n is equal to 1 is plotted and the recording power at which the product is 0 on the approximated line is Pthr.

In the above description, a linearity comparison is performed between two values. This embodiment is not limited to this. In this embodiment, a linearity comparison can be made among three values or more. For example, an exponent corresponding to the highest linearity value can be determined among the three values 2, 2.5, and 3.

According to this embodiment, an exponent n corresponding to higher linearity among at least two values is calculated based on a correlation between (i) the test recording power and (ii) the product of the modulation coefficient and the nth degree of the test recording power (n is real a number other than 1). Thus, the corresponding recording power can be determined without relying on the range of test recording power.

(Embodiment 3)

Below, with reference to FIG. 14, an embodiment 3 of a recording power determination method and a recording power determination apparatus according to the present invention is described.

The recording power determining apparatus 108 according to this embodiment has substantially the same structure as the recording power determining apparatus described in Embodiment 1 with reference to FIG. 5. The optical disk device 100 including the recording power determining apparatus 108 according to this embodiment also has substantially the same structure as the structure in the optical disk device described in Embodiment 1 with reference to FIG. 2. In order to avoid redundancy, the recording power determining apparatus 108 and the optical disc apparatus 100 according to this embodiment will not be described with respect to details that are the same as those in Embodiment 1.

The recording power determination method of this embodiment is described with reference to FIG. 13.

As described above, the optical disc 101 corresponding to the BD format has the values Pind, ρ, k and Mind stored on it in a predetermined area. As shown in step S32 in FIG. 13, the reproducing section 104 reads the values of Pind, ρ, k and Mind from the optical disk 101. Then, the reproducing section 104 outputs a signal 105 indicating the values of Pind, ρ, k and Mind to the power determining device 108 records.

As shown in step S34 in FIG. 13, the recording power determining apparatus 108 confirms that the largest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and that the smallest modulation coefficient of the plurality of modulation coefficients is smaller than the Mind value.

Before recording test data, the recording power determining device 108 determines the test recording power values AH, so that the difference between each adjacent test recording power is equal to or less than 10% of the Pind value.

After recording test data at test recording power values A-H, the reproducing section 104 measures a plurality of modulation coefficients corresponding to a plurality of test recording power values. The playback section 104 outputs a signal 107 indicating a plurality of modulation coefficients corresponding to a plurality of test recording power values to a recording power determining apparatus 108.

The calculation section 402 in the recording power determination apparatus 108 confirms that the largest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value, and that the smallest modulation coefficient of the plurality of modulation coefficients is smaller than the Mind value. In particular, the calculation section 402 determines whether the largest modulation factor is really less than the Mind value. If it is determined that the largest modulation coefficient is smaller than the Mind value, the calculation section 402 sets a plurality of test recording powers higher than the previous test recording power, and the output section 403 outputs a signal 109 indicating the newly set test recording powers to section 210 entries. The recording section 210 records test data with newly set test recording powers. The reproducing section 104 reads the newly recorded test data, and the calculating section 402 again determines whether the largest modulation factor is really less than the Mind value. Until the playback section 104 measures a modulation coefficient greater than the Mind value, the calculation section 402 sets a plurality of test recording powers greater than the previous test recording powers.

Section 402 of the calculation also determines whether the smallest modulation factor is greater than the value of Mind. If it is determined that the smallest modulation coefficient is larger than the Mind value, the calculation section 402 sets the plurality of test recording powers lower than the previous test recording powers, and the output section 403 outputs a signal 109 indicating the newly set test recording powers to section 210 entries. The recording section 210 records these test data at newly set test recording powers. The playback section 104 reads this newly recorded test data, and the calculation section 402 again determines whether the smallest modulation factor is really larger than the Mind value. Until the playback section 104 measures that the modulation coefficient is smaller than the Mind value, the calculation section 402 sets the plurality of test recording powers to less than the previous test recording powers.

Thus, the calculation section 402 confirms that the largest modulation coefficient is larger than the Mind value, and that the smallest modulation coefficient is smaller than the Mind value.

14 (a) is a graph illustrating a relationship between a test recording power value and a modulation coefficient. Section 402 of the calculation confirms that the modulation coefficient corresponding to the smallest value H of the test recording power is equal to or less than the value Mind, and that the modulation coefficient corresponding to the largest value A of the test recording power is larger than the value Mind, as shown in FIG. .14 (a).

Then, after confirming that the largest modulation coefficient is larger than the Mind value, and that the smallest modulation coefficient is smaller than the Mind value, calculation section 402 calculates the product of each of the plurality of modulation coefficient values and the square of each of the plurality of test recording powers .

14 (b) is a graph illustrating the relationship between (i) the test recording power value and (ii) the product of the modulation coefficient and the square of the test recording power value.

Then, with reference to S36 in FIG. 13, the calculation section 402 constructs an approximated line indicating a correlation between the plurality of test recording powers and the plurality of products, and calculates the recording power P500 at which the product is 0 on the approximated line, as shown in FIG. .14 (b).

Then, as shown in step S38 in FIG. 13, the calculation section 402 calculates the recording power Pw1 for recording user data based on the recording power P500 in accordance with the following expression 1.

Pw1 = P500 × (-1 / k + 2) × ρ Expression 1

The output section 403 outputs a signal 109 indicating the recording power Pw1 to the recording power setting section 110.

According to this embodiment, the relationship between the modulation coefficient and the Mind value is checked and the smallest modulation coefficient is smaller than the Mind value, and that the largest modulation coefficient is larger than the Mind value. Thus, data is recorded at a test recording power in a range that is close to the range of test recording powers used by the disc manufacturer to determine Pind. Therefore, the recording power recommended by the disc manufacturer can be obtained more accurately.

In the above description, it is confirmed that the smallest modulation coefficient is smaller than the Mind value, and that the largest modulation coefficient is larger than the Mind value. A condition may be added that the smallest test recording power among a plurality of test recording powers should be equal to or greater than 0.9 of the recording power at which the modulation factor is substantially equal to the Mind value. Under this condition, data is recorded at a test recording power in a range closer to that used by the disc manufacturer to determine Pind. Therefore, the recording power recommended by the disc manufacturer can be obtained even more accurately.

A condition may be added that the largest test recording power of the plurality of test recording powers is equal to or less than 1.1 of the recording power at which the modulation factor is substantially equal to the Mind value. Under this condition, data is recorded at a test recording power in a range even closer to the range used by the disc manufacturer to determine Pind. Therefore, the recording power recommended by the disc manufacturer can be obtained even more accurately.

In addition, the condition may be added that the smallest value of the test recording power is equal to or greater than 0.9 of the recording power, at which the modulation coefficient is essentially equal to the value of Mind, and the largest value of the test recording power is equal to or less than 1.1 from the recording power at which the modulation coefficient is essentially equal to the value of Mind. Under this condition, the recording power recommended by the disc manufacturer can be obtained even more accurately.

The boundary of the largest value of the test recording power or the smallest value of the test recording power with respect to the recording power, at which the modulation coefficient is equal to the Mind value, does not have to be 10%, as long as the data is recorded at a test recording power in the range close to the range used by the disk manufacturer to determine Pind.

As can be estimated from the graph in FIG. 14 (a), when the recording power becomes larger, the width of the marks formed on the optical disk 101 increases, leading to an increase in the modulation coefficient. When the recording power reaches a certain value, the width of the marks is limited by the width of the track and thus saturated. Accordingly, the modulation coefficient is also saturated. The value of the recording power can be classified into three ranges in terms of the ratio of the modulation coefficient. In the first recording power range, the modulation coefficient increases without affecting the track width (less than the value H of the test recording power). In the second range of recording power, the modulation coefficient increases under the influence of the track width (from the value H of the test recording power to the value A of the test recording power). In the third recording power range, the modulation coefficient is saturated under the influence of the track width (more than the value A of the test recording power).

As shown in FIG. 14 (b), with a recording power ranging from a test recording power A to a test recording power H, a correlation between (i) the test recording power and (ii) the product of the modulation coefficient and the squared value test recording power detects high linearity. Conversely, when the recording power is greater than the value A of the test recording power, or the recording power is smaller than the value H of the test recording power, the width of the marks is determined by various factors. Therefore, the correlation does not necessarily show high linearity.

The range between the critical recording power for labeling and the test recording power H is very narrow. When the recording power is greater than the value A of the test recording power, it is difficult to detect a change in the optimal recording power caused by external influences, since the modulation coefficient reaches saturation. Accordingly, a suitable range of the modulation coefficient used to determine the recording power is the range in which the modulation coefficient varies under the influence of the track width.

The recording power is in the range in which the modulation coefficient increases without affecting the width of the track in the case when, for example, dust adhered to the optical disk 101 or the optical head 102; external action, such as relative tilt or defocus, takes place between the optical disk 101 and the optical head 102; or the intensity of the optical beam emitted by the optical head 102 decreases when the temperature of the optical head 102 changes. The recording power is in a range in which the modulation coefficient is saturated under the influence of the track width when, for example, the intensity of the optical beam emitted by the optical head 102 increases when the temperature of the optical head 102.

In the above description, when the modulation coefficient corresponding to the test recording power H is greater than the Mind value, a plurality of test recording powers are set lower than the previous test recording powers and the test data is recorded at newly set test recording powers. Similarly, when the modulation coefficient corresponding to the test recording power value A is smaller than the Mind value, a plurality of test recording power values are set to be larger than the previous test recording power values, and test data is recorded at newly set test recording power values. This embodiment is not limited to this. The recording power can be determined using only a predetermined range of modulation coefficients with an expandable range of test recording powers.

However, in order to expand the range of test recording power, it is necessary either to expand the difference between each adjacent value of the test recording power, or to expand the range used to determine the recording power. The former decreases the accuracy, and the latter increases the time until the recording power is obtained, or excessively quickly wears out the area used to determine the recording power. Especially in the case of write-once-write optical discs, onto which data cannot be overwritten, it is not a preferable option to expand the area used to determine the recording power. Accordingly, it is preferable to make the difference between each adjacent value of the test recording power equal to or less than 10% of the Pind value, record the test data so that the 8T marks in the recording area are equal to or less than one track, and only when the modulation coefficients are not in within a predetermined range, re-set the range of test recording power for recording test data. With this arrangement, the recording power can be determined with high accuracy within a short period of time.

As described above, according to the recording power determination method and the recording power determination apparatus of this embodiment, a suitable recording power can be determined.

(Embodiment 4)

Below, with reference to FIG. 15, an embodiment 4 of a recording power determination method and a recording power determination apparatus according to the present invention is described.

In Embodiment 3, the first recording power is calculated based on the relationship between (i) each of the plurality of test recording powers and (ii) the product of each of the modulation coefficients and the square of each test recording power. The present invention is not limited to this.

In this embodiment, a case is described in which the exponent is 1.

The recording power determining apparatus 108 according to this embodiment has substantially the same structure as the recording power determining apparatus described in Embodiment 1 with reference to FIG. 5. The optical disc device 100 including the recording power determining apparatus 108 according to this embodiment also has substantially the same structure as the structure of the optical disc device described in Embodiment 1 with reference to FIG. 2. In order to avoid redundancy, the recording power determining apparatus 108 and the optical disc apparatus 100 according to this embodiment will not be described with respect to details that are the same as in Embodiment 1.

As described above, the optical disc 101 corresponding to the BD format has the values Pind, ρ, k and Mind stored on it in a predetermined area. The recording power determining apparatus 108 according to this embodiment is substantially the same as the recording power determining apparatus described in Embodiment 3, in which the recording power determining apparatus 108 confirms that the largest modulation coefficient among the plurality of modulation coefficients is larger than the value Mind, and that the smallest modulation coefficient among the plurality of modulation coefficients is smaller than the Mind value. Therefore, the recording power determining apparatus 108 according to this embodiment will not be described with respect to details that are the same as in Embodiment 3.

15 (a) is a graph illustrating a relationship between a test recording power value and a modulation coefficient corresponding to a test recording power. The calculation section 402 in the recording power determination device 108 confirms that the modulation coefficient corresponding to the smallest value of the test recording power H is smaller than the Mind value, and that the modulation coefficient corresponding to the largest value of the test recording power A is greater than the Mind value, as shown in FIG. 15 (a).

Then, after confirming that the largest modulation coefficient is larger than the Mind value, and that the smallest modulation coefficient is smaller than the Mind value, the calculation section 402 calculates the product of each of the plurality of modulation coefficient values and each of the plurality of test recording power values.

15 (b) is a graph illustrating the relationship between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power.

As shown in FIG. 15 (b), the calculation section 402 constructs an approximated line indicating a correlation between the plurality of test recording powers and the plurality of products, and calculates the recording power P1500 at which the product is 0 on the approximated line. Then, the calculation section 402 calculates the recording power Pw1 for recording data in accordance with the following expression 3.

Pw1 = P1500 × k × ρ Expression 3

According to this embodiment, the relationship between the modulation coefficient and the Mind value is checked, and it is confirmed that the smallest modulation coefficient of the plurality of modulation coefficients is smaller than the Mind value, and that the largest modulation coefficient of the plurality of modulation coefficients is larger than the Mind value. Thus, data is recorded at a test recording power in a range that is close to the range of test recording powers used by the disc manufacturer to determine Pind. Therefore, the recording power recommended by the disc manufacturer can be obtained more accurately.

In the above description, it is confirmed that the smallest modulation coefficient is smaller than the Mind value, and that the largest modulation coefficient is larger than the Mind value. A condition may be added that the smallest value of the test recording power is equal to or greater than 0.9 of the recording power at which the modulation factor is substantially equal to the value of Mind. Under this condition, data is recorded at a test recording power in a range close to the range used by the disc manufacturer to determine Pind. Therefore, the recording power recommended by the disc manufacturer can be obtained even more accurately.

A condition may be added that the largest value of the test recording power is equal to or less than 1.1 of the recording power at which the modulation coefficient is substantially equal to the value of Mind. Under this condition, data is recorded at a test recording power in a range closer to the range used by the disc manufacturer to determine Pind. Therefore, the recording power recommended by the disc manufacturer can be obtained even more accurately.

In addition, a condition may be added that the smallest value of the test recording power is equal to or greater than 0.9 of the recording power, at which the modulation coefficient is substantially equal to the value of Mind, and the largest value of the test recording power is equal to or less than 1.1 of the recording power at which the modulation factor is substantially equal to the Mind value. Under this condition, the recording power recommended by the disc manufacturer can be obtained even more accurately.

The boundary of the largest value of the test recording power or the smallest value of the test recording power with respect to the recording power, at which the modulation coefficient is equal to the Mind value, does not have to be 10%, while the data is recorded at a test recording power in the range close to the range used manufacturer of discs for determining pind.

In the case where the exponent is 1, as shown in FIG. 15 (b), the linearity of the correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power cannot be as high as the linearity of the correlation in in the case where the exponent is 2. Due to the difference in the established range of the test recording power, the recording power Pthr at which the product is 0 may fluctuate slightly. Therefore, in the case where the exponent is 1, it is preferable to record data at test recording power values in a range that is closer to the range used by the disc manufacturer to determine Pind than the range in Embodiment 3. In Embodiment 3, the linearity of correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the test recording power is high.

In the above description, when the modulation coefficient corresponding to the test recording power H is greater than the Mind value, a plurality of test recording powers lower than the previous test recording powers are set again, and the test data is recorded at the newly set test power values records. Similarly, when the modulation coefficient corresponding to the test recording power A is lower than the Mind value, a plurality of test recording powers greater than the previous test recording powers are set again, and test data is recorded at newly set test power values records. Alternatively, the recording power can be determined using only a predetermined range of modulation coefficients with an expandable range of test recording powers.

However, in order to expand the range of test recording power, it is necessary either to increase the difference between each adjacent value of the test recording power, or to expand the range used to determine the recording power. The former decreases accuracy, and the latter increases time until the recording power is determined. Accordingly, like in Embodiment 3, it is preferable to make the difference between each adjacent test recording power value equal to or less than 10% of the Pind value, to record test data in the recording area equal to or less than one track, and only when the recording power cannot be determined, re-set the range of test recording power for recording test data. With this arrangement, the recording power can be determined with high accuracy within a short period of time.

In embodiments 3 and 4, the values of the exponent are 1 and 2. The exponent can be any real number. In Embodiments 3 and 4, as described above in Embodiment 2, an exponent n can be chosen such that the linearity of the correlation between (i) the value of the test recording power and (ii) the product of the modulation coefficient and the n-th degree of the test recording power is high. In this case, since the linearity of the correlation corresponding to the value of the exponent n is high, the recording power at which the product is 0 is determined essentially unique, even if the range of the test recording power is wide. Therefore, the corresponding recording power can be determined in a shorter period of time. In this case, it is also preferable to write the selected value of the exponent n to the optical disc. By recording the exponent n on an optical disc, the degree of freedom of the disc manufacturer can be expanded to create a recording film.

As described above in embodiments 3 and 4, the Mind value is read from the optical disc 101, and the product of the modulation coefficient and the nth power of the write power is calculated with respect to the Mind value so that a suitable write power for recording data can be determined.

The optical disk device in embodiments 1-4 writes data to the optical disk and reproduces data recorded on the optical disk. The present invention is not limited to this. The present invention is applicable to any information recording apparatus for recording data at a plurality of test recording powers before recording data.

In embodiments 1 through 4, the optical disk is used as an information storage medium. The present invention is not limited to this. The present invention is applicable to any information storage medium for which recording power is to be determined.

In embodiments 1 through 4, data is recorded in a modulation system with a limited recording length (1, 7). The present invention is not limited to this. Other recording systems may be used according to the present invention. In the case where a modulation system other than a modulation system with a recording length restriction is used (1, 7), it is preferable to record test data corresponding to a signal indicating a large number of the longest marks and the longest intervals of the system, continuous with respect to each other. According to the present invention, any single period signal may be used. In the case where a single-period signal is used, it is preferable that the signal amplitude is approximately the same as the signal amplitude of the longest marks and the longest gaps.

In embodiments 1 to 4, peak power (Pp), bias power (Pe), and lower power value (Pbw) are common to all marks, and Tmp is also common to all marks. The present invention is not limited to this. Other parameters can be used to determine the recording power.

In embodiments 1 to 4, Ttop, dTtop, and dTe are classified into three classes of 2T, 3T, and 4T or more. The present invention is not limited to this. Ttop, dTtop and dTe can be classified in any other way.

In embodiments 1 to 4, the relationship between peak power, bias power, and lower power value is constant. The present invention is not limited to this. Peak power, bias power and lower power value can be determined independently. For example, these power values may be separately determined such that the bias power and the lower power value are fixed during peak power determination.

In embodiments 1 through 4, test data is recorded at eight test recording powers. The present invention is not limited to this. The present invention is applicable to any case where data is recorded at a plurality of test recording powers.

In embodiments 1 to 4, the recording power determining device 108 determines the test recording power AN values in advance. The present invention is not limited to this. It is not necessary that the recording power determination device 108 determines the test recording power AH values in advance. The recording power setting section 110 may provide a signal indicating A-H test recording powers in the laser control circuit 112 to the recording power determining apparatus 108.

In embodiments 1 through 4, the recording power determining device 108 determines the recording power. The present invention provides essentially the same effect, even when a recording power determination apparatus and other peripheral elements are integrated in the ICs.

Industrial applicability

According to the recording power determination method and the recording power determination apparatus according to the present invention, a suitable recording power can be determined, and therefore, data can be recorded properly. In addition, the optical disc can be prevented from unnecessarily rapid deterioration. The present invention is particularly effective in an optical disc device conforming to the BD format, which requires more precise adjustment of the recording power for a higher recording density.

Claims (4)

1. A device for recording information containing:
a recording section for recording data on an information storage medium using an optical beam;
a reading section for reading data recorded on the information storage medium; and
a recording power determining apparatus for determining an optical beam recording power used when the recording section writes data to the information storage medium;
wherein
the recording section writes test data to the information storage medium with a plurality of test recording power values;
the reading section reads the test data recorded on the information storage medium at each of the plurality of test recording power values, generates a signal and measures a signal modulation coefficient corresponding to each of the plurality of test recording power values; and
the recording power determination apparatus calculates an nth power product of each of a plurality of test recording power values and a modulation coefficient corresponding thereto to obtain a plurality of products corresponding to a plurality of test recording power, calculates a first recording power based on a correlation between a plurality of test recording power and a set of works and calculates the recording power based on the first recording power, where n is an exponent and is a real number, from personal from 1, and the recording section writes data to the information storage medium with the calculated recording power of the optical beam. 2. An information storage medium having an information recording area for determining an optical beam recording power for recording data, wherein
the information is n, where n is an exponent and is a real number other than 1, and the product of the nth degree of each of the set of test recording powers and the modulation coefficient corresponding to it is used to obtain a correlation between the test recording powers and works. 3. A computer-readable recording medium storing instructions for determining a recording power of an optical beam for recording data on an information storage medium that, when executed by a computer, forces the computer to perform a method comprising the steps of:
receiving a signal indicating a plurality of modulation coefficients corresponding to a plurality of test recording power values;
obtaining a plurality of products corresponding to a plurality of test recording power values by calculating a product of the nth power of each of the plurality of test recording power values and a modulation coefficient corresponding to it, where n is an exponent and is a real number other than 1;
calculating a first recording power based on a correlation between a plurality of test recording power values and a plurality of products; and
calculating the recording power based on the first recording power; and recording data at this calculated recording power. 4. A method of recording information for recording data on an information storage medium with recording power after determining the recording power of the optical beam for recording data, comprising the steps of:
write test data to the information storage medium with a plurality of test write power values,
reading test data recorded at each of the plurality of test recording power values, generating a signal and measuring a modulation coefficient of this signal corresponding to each of the plurality of test recording power;
calculating the product of the nth power of each of the plurality of test recording powers and the modulation coefficient corresponding to it, thereby obtaining a plurality of products corresponding to the plurality of test recording powers, where n is an exponent and is a real number other than 1;
calculating a first recording power based on a correlation between a plurality of test recording power values and a plurality of products;
calculating the recording power based on the first recording power and recording data at this recording power.

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