Patent Application
20100039912
The present invention relates to an optical information recording/reproducing unit, a method of measuring a recorded-mark quality, and a record control method and, more particularly, to an optical information recording/reproducing unit that irradiates a laser beam onto an optical information recording medium, to perform data recording and data reproduction, as well as a method of measuring a recorded-mark quality and a record control method used in such an optical information recording/reproducing unit.
In the field of data storage, the data volume to be treated is ever increasing together with the diversification of information, etc. In the optical disc, effort of increasing the memory capacity has been continued from CDs to DVDs by increasing the memory density. For the effort of technical development toward the higher density, there have been developed a technique of accurately recording marks with a size as small as possible, a technique of accurately reproducing data even below the vicinity of limit of optical reproduction. Hereinafter, these techniques will be described with reference to recordable DVDs.
As the recordable DVDs, optical discs such as DVD-RAM, DVD-R, DVD-RW, DVD+R, and DVD+RW, have appeared on the market. Some optical disc drives that perform recording/reproducing on the recordable optical discs have a recording speed as high as up to a 16× speed. Generally, the recordable optical disc has an area (PCA: power calibration area) in a part of the disc area for calibrating therein the recording power, and the optical disc drive uses this area to perform control of the optical power (OPC: optimum power control) at a suitable timing. The optical disc drive, upon the data recording, performs recording using the power obtained by the recording power calibration. Known examples of the recording power calibration include a beta technique that obtains a beta (β) value by inspecting asymmetry from the reproduced amplitude of a long mark and the reproduced amplitude of a short mark, a gamma technique that judges a state from the degree of amplitude saturation of a recorded mark, etc.
As to the recording-laser-pulse waveform (laser-emitted waveform during the recording), referred to as recording strategy, is selected based on the information provided beforehand on the disc, and/or information stored in the optical disc drive depending on the specification and type of the optical disc medium.
As the techniques for calibration of the recording waveform, there are techniques described in, for example, Patent Publications-1 to -3. Patent Publication-1 uses a technique of optimizing the recording pulse without being affected by the skill etc. of the engineer, by iterating a combination of test recording while changing the pulse setting and measuring of the jitter obtained by detecting the signal reproduced therefrom to thereby optimize the recording pulse. Patent Publication-2 performs correction of the time width of the recording waveform based on the error between the data width of the reproduced signal reproduced from the recorded data and the reference data width. Patent Publication-2 describes that the recording accuracy can be improved by using a specific pattern in this process. Patent Publication-3 discloses a technique of detecting the edge interval of the recorded mark or space (duty ratio of mark or space) and the change of recording condition, to adjust the edge position of the recording pulse. These techniques obtain the error of the reproduced signal with respect to the reference, i.e., a deviated amount along the time axis (such as jitter or time interval) after directly converting the reproduced signal into pulses.
Next, a reproduction technique will be described. Conventionally, binarization of data used a slice-discrimination technique. This technique uses an equalizer that performs filtering of the reproduced waveform so as to reduce the intersymbol interference. In this case, since the equalizer increases the noise component while suppressing the intersymbol interference, it is difficult to decode the recorded original data from the reproduced signal if a higher-density-recording is used. On the other hand, there is a partial-response maximum likelihood (PRML) technique, as a technique effective to accurately decode the data recorded with a higher density. In this technique, the reproduced waveform is subjected to partial-response (referred also to as PR hereinafter) equalization to be converted into a waveform having an intersymbol interference, and then to a data discrimination using a technique known as Viterbi decoding (ML). The PR equalization is specific by the amplitude of each data period (clock), and PR(abc), for example, is such that the amplitude at time instant 0 is “a”, amplitude at time instant T is “b”, the amplitude at time instant 2T is “c”, and the amplitude at other time instants is zero. The total number of components having an amplitude not zero is referred to as restricted length. For improvement of the density, it is effective to use a partial-response waveform having a longer restricted length. This conversely means the assumption that “a longer restriction-length waveform corresponds to a waveform having a larger intersymbol interference.”
As an example, a PR(1,2,2,2,1) characteristic will be described. The PR(1,2,2,2,1) characteristic means the characteristic wherein the reproduced signal corresponding to binary bit “1” assumes “12221”, and computation of convolution between the binary bit series and series “12221” showing the PR characteristic provides a reproduced signal. For example, the reproduced signal calculated from a binary bit series “0100000000” assumes “0122210000.” Similarly, the reproduced signal calculated from a binary bit series “0110000000” assumes “0134431000” the reproduced signal calculated from a binary bit series “011100000” assumes “0135653100”, the reproduced signal calculated from a binary bit series “0111100000” assumes “0135775310”, and the reproduced signal calculated from “0111110000” assumes “0135787531.” Such a reproduced signal calculated by the calculation of convolution is an ideal reproduced signal (path).
The reproduced signal assumes nine levels in the PR(1,2,2,2,1) characteristic. However, the actual reproduced signal does not necessarily have the PR(1,2,2,2,1) characteristic, and includes a degradation factor, such as noise. In the PRML detection, the reproduced signal is rendered close to the PR characteristic by using the equalizer. The reproduced signal rendered close to the PR characteristic is referred to as an equalized reproduced signal. Thereafter, a discriminator (such as Viterbi decoder) is used to select a path having a smallest Euclid distance with respect to the equalized reproduced signal. The path and binary bit series have therebetween a 1:1 relationship. The Viterbi decoder that performs Viterbi decoding operation outputs the binary bit series corresponding to the selected path, as the decoded binary data. A system using the PRML premises that the reproduced signal has three- or more-value data, i.e., multiple-value data instead of the binary data. The slice-discrimination detection technique judges presence or absence of the pit by using a suitable slicing, and then uses binary equalization for the data reproduction. On the other hand, the PRML detection premising the multiple-value data requires a recording/reproducing waveform that is suitable for the PRML detection, unlike the slice-discrimination detection.
The inventors of the present invention disclose, in Patent Publication-4, means for detecting an item corresponding to the amplitude or asymmetry in the case of using the PRML detection. In this publication, an asymmetry detection circuit includes a timing adjustment circuit that receives a digitized sampled value, a Viterbi detector that receives the sampled value, a reference-level judgment unit that receives the output of the Viterbi detector, a filter circuit that receives the output of the Viterbi detector, an error calculation unit that calculates a difference between the output of the filter and the output of the timing adjustment circuit, a plurality of discrimination circuits that discriminate the output of the error detection circuit by using the output of the reference-level judgment unit as a discriminating signal, a plurality of integration circuits that integrate the output of the plurality of discrimination circuits, and an average calculation circuit that calculates the average of the maximum integrated reference level and the minimum integrated reference level selected from among the outputs of the integration circuits, and executes a calculation operation that calculates the difference between the median integrated reference level corresponding to the central level of the plurality integrated reference values and the above average.
A system is practically used that applies the technique of PRML (partial-response maximum-likelihood) technique onto an optical disc having a higher recording density than the DVD. Non-Patent-Document-1 reports that it is possible to calibrate the recording power by using the PRSNR as the SNR (signal-to-noise ratio) of the PR system in such a system. Non-Patent-Document-2 reports the PRSNR.
Patent Publication-1 (JP-2005-216347A);
Patent Publication-2 (JP-2002-230770A);
Patent Publication-3 (JP-1993-135363A);
Patent Publication-4 (JP-2002-197660A);
Non-Patent-Document-1 (Jpn. J. Appl. Phys., Vol. 43, No. 7B (2004), “Optimization-of-Write-Conditions-with-a New Measure in High-Density-Optical-Recording”, M. Ogawa et al.; and
Non-Patent-Document-2 (ISOM2003 (International Symposium Optical Memory 2003), Technical Digest pp. 164-165 “Signal-to-Noise Ratio in a PRML Detection” S. OHKUBO et al.
In the conventional calibration of the recording condition, the quality of signal recorded at a recording density comparable to that of the DVD and CD is obtained by using a deviation of the reproduced signal, which is directly binarized as by level-slicing the reproduced signal, with respect to the reference level, detecting the deviated amount of the jitter, time interval etc. in the time axis direction, and optimizing the recording power and recording waveform by performing correction based on these values. On the other hand, for a signal recorded at a higher density up to the degree of allowing use of the PRML detection technique, a level slice detection cannot be applied to a short mark, and is unable to directly measure the signal deviation in the view point of the accuracy, unlike to the conventional technique. Thus, the recording quality of the signal recorded at a higher recording density is obtained by optimization of the recording power and recording waveform by using the PRSNR, error rate, and/or asymmetry correlated with these values.
In the optimization of recording condition, a large number of parameters are optimized to determine the optimum condition. However, the optimization of recording condition may in fact encounter locally-optimized parameters, even if an apparently suitable result is obtained. For example, even if the recording waveforms (time widths) are the same in the time direction with respect to the recording compensation setting in a specific pattern during the recording, there may be a difference therebetween in the power margin for the same power and the same performance if the recording start positions of the recording waveforms are different.
In the conventional techniques, there is no known technique that is capable of easily confirming whether or not the recorded signal that is recorded after optimizing the large number of parameters is optimum to the PRML detection technique, especially including the view point of margin. Thus, there arise the problem that, upon determining the recording power based on the performance index, a locally-optimized condition may be determined as the optimum recording condition if it is found optimum in the local condition, although there may exist in fact a recording condition that achieves a wider power margin.
With reference to
For the above problem of local optimality, it may be considered to measure the margin for all the parameter conditions, and select the condition therefrom; however, this requires a larger time length for obtaining the optimum solution, and consumes a larger area. In addition, if the optical heads have a significant range of variation therebetween in the performance thereof, determination of the condition by using a specific optical head after a long-time operation thereof cannot necessarily provide the optimum condition for a number of drives, if such drives are manufactured in a mass production. In this case, there arises the problem that the drives manufactured in the mass production suffer from a lower product yield, as a result of poor adaptability.
It is an object of the present invention to solve the above problems of the conventional techniques and to provide a method of measuring the quality of recorded mark in an optical information recording/reproducing unit, which is capable of detecting with a higher degree of accuracy the deviation of the position at which the recorded mark is formed by a high-density recording, and the optical information recording/reproducing unit that uses the method.
The present invention provides an optical information recording/reproducing unit including: a reproducing section (10) that reads out a mark and a space recorded on an optical information recording medium to generate a reproduced signal waveform; a reference-waveform generation section that generates a reference reproduced-waveform obtained by applying a specific response characteristic to a data train corresponding to the reproduced signal waveform; a transient-equalization-error calculation section that calculates, as a transient equalization error, a difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value group at m channel clocks (m is an integer not less than one) before or after the time instant of the specific level-value satisfy therebetween a specific relationship.
The present invention provides a method for measuring a recorded-mark quality of an optical information recording medium, that finds the recorded mark quality from a reproduced signal that is read from a mark and a space recorded on the optical information recording medium, the method including: generating a reproduced signal waveform from the recorded mark and space; generating a reference reproduced-waveform obtained by applying a specific response characteristic to a data train corresponding to the reproduced signal waveform; calculating, as a transient equalization error, a difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value group at m channel clocks (m is an integer not less than one) before or after the time instant satisfy therebetween a specific relationship.
The present invention provides a record controlling method for an optical information recording medium in an optical information recording/reproducing unit, including: generating a reproduced signal waveform from a recorded mark and space recorded on the optical information recording medium; generating a reference reproduced-waveform obtained by applying a specific response characteristic to a data train corresponding to the reproduced signal waveform; calculating, as a transient equalization error, a difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value group at m channel clocks (m is an integer not less than one) before or after the time instant satisfy therebetween a specific relationship; and controlling a shape of a recording laser pulse that irradiates the optical information recording medium upon data recording so that the transient equalization error decreases.
The above and other objects, features and advantages of the present invention will be more apparent from the following description, referring to the accompanying drawings.
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
The controller 50 controls the drive for the overall operation thereof. The PUH 10 configures a reproducing section in the present invention, and irradiates a laser beam onto the optical disc 60 to receive the reflected light thereof. The servo information detector 70 generates a signal for servo-driving the PUH 10 based on the information from the PUH 10. In the servo technique, the PUH 10 itself or the objective lens 11 of the PUH 10 is finely or roughly controlled for positioning-control thereof in the radial direction of the optical disc 60, and in the direction perpendicular to the recording surface of the optical disc 60. In addition, based on the tilt detected between the optical disc 60 and the PUH 10, the tilt is controlled for correction thereof. These units have their own parameters.
Upon recording onto the optical disc 60, binary recording data is input to the LD drive circuit 13. The binary recording data has been converted by a modulator not shown into a series of data wherein the minimum run length assumes “1”, i.e., “0” or “1” in the binary bit series continues at least two in number. The binary recording data is converted into a recording waveform by the LD drive circuit 13 in accordance with the recording condition (parameters) output from the controller 50. The recording waveform of the electric signal is converted into an optical signal in the optical head, and irradiated onto the optical disc from the LD 12. Recorded marks are formed on the optical disc 60 in accordance with the irradiation of laser.
The spindle drive circuit 18 rotates the optical disc 60 upon recording and reproduction. An optical disc attached with a guide groove is used as the optical disc 60. The controller 50 iterates the judgment of whether or not a record-interrupt condition defined beforehand is satisfied after the recording is started. The controller 50 interrupts the recording, upon judging that the record-interrupt condition is satisfied, and then performs reproduction of the recorded area including the area in which the record is interrupted.
Back to
The signal-quality detector 40 calculates a transient equalization error based on the equalized reproduced signal output from the equalizer 22 and the binary data (estimated data train) output from the discriminator 30.
The equalization-error calculation unit 43 calculates equalization error information showing the error between the reference reproduced-waveform and the equalized reproduced-signal waveform. The transient-equalization-error detector 44 extracts the equalization error information as the transient equalization error at a time instant at which the reference reproduced-waveform assumes a specific value, and at which the specific value and the reference reproduced-waveform at another time instant which is m channel clocks (m is an integer not smaller than 1) before or after the time instant satisfy therebetween a specific relative relationship. The transient-equalization-error detector 44 includes an integration circuit that integrates together the transient equalization errors extracted and an average calculation circuit that calculates the average from the integrated value integrated by the integration circuit, although illustration thereof is omitted herein. The integration and calculation of the average by theses circuits are performed in an arbitrary period, for example, by ECC block. In an alternative, the integration and calculation may be performed by a plurality of ECC blocks as a unit, may be performed by a sector or frame, or may be performed by a combination of those periods as a unit.
In the above description, calculation of the equalization error used the estimated data train output from the discriminator 30; however, the equalization error information may be calculated using the data train (original data) actually used for the recording instead.
Hereinafter, description is given to the quality index that is used in the present exemplary embodiment and shows the positional deviation of the recorded mark. The condition assumed here is such that a mark or space recorded in a (1, 7) RLL constraint is to be subjected to a PR(12221)+ML detection, such that the reproduced signal waveform is reproduced from the information including the mark and space recorded on the optical information recording medium and the reference reproduced-waveform is obtained by inputting the reproduced signal waveform to the discriminator, which provides an estimated data train therefrom, and by applying the PR12221 thereto, as the specific response characteristic, and such that the equalized error waveform that is calculated as the difference between these waveforms is obtained as a continuous train of level-values corresponding to the channel clock.
The controller 50 (
Hereinafter, the level-value recognition will be described. Considering that the level changes to level “4” from a time instant one channel clock before, for example, the state transition diagram shown in
As to the above path-1, the specific value (level-value “4”) corresponds to the mark, and the level-value at one channel clock before corresponds to the space because the level is different from the specific value, whereby it is defined that the level “4” in the path-1 corresponds to the front edge of a 2T mark. Similarly, the specific value in the path-2 corresponds to the space, the level at one channel clock before corresponds to the mark because the level is different from the specific value, whereby it is determined that the level “4” in the path-2 corresponds to the front edge of a 2T space. In other word, for the case where the level-value “4” is the specific value, the transition of level-value is such that the path-1 corresponds to 5(space)→4 (mark) and the path-2 corresponds to 3(mark)→4(space). The transient equalization error corresponding to the path-1 is denoted by a transient equalization error (LH 2TF) that corresponds to the front edge of the 2T mark, whereas the transient equalization error corresponding to the path-2 is denoted by a transient equalization error (HL 2TF) that corresponds to the front edge of the 2T space.
Considering the case, where the level changes from the level-value “4” at one channel clock after, in the state transition diagram showing in
As to the front edge and rear edge of a 3T mark or 3T space, since the level-values “2” and “6” are the values that only the 3T pattern assumes after the PR(1,2,2,2,1) equalization, these level-values can be defined by the level-values “5” and “3” in a transition from the level-value “5” to the level-value “6” or in the opposite direction thereof, and a transition from the level-value “3” to the level-value “2” or in the opposite direction thereof. As to the front edge and rear edge of a 4T or longer mark or a 4T or longer space, these level-values can be defined by the level-values “5” and “3” in a transition from the level-value “5” to the level-value “7” or in the opposite direction thereof, and a transition from the level-value “1” to the level-value “3” or in the opposite direction thereof. The equalization error for the front edge and rear edge of these marks or space are defined as a transient equalization error corresponding to the respective mark lengths or respective space lengths.
The following Table 1 shows the transient equalization errors for the front edge and rear edge of those mark lengths and space lengths.
Table 1 shows that the specific value is determined at, for example, “4” and that the transient equalization error (LH 2TF) corresponding to the front edge of the 2T mark, for example, is defined by the equalization error at the level-value “4” during the transition from “5” to “4” in the level-value.
It is to be noted that the optical disc media include ones wherein the reflectance thereof changes from “low” to “high” along with a change from the non-recorded state to the recorded state. i.e., the mark is recorded to be brighter than the space, and others wherein the reflectance thereof changes from “high” to “low” along with the same state change, i.e., the mark is recorded to be darker than the space. With respect to the mark or space in those media, the correspondence (polarity) of the reproduced (input) signal is arbitrarily changed by the signal processing performed later, and handled in the specific definition of the device, controller measurement unit and human operation, whereby the correspondence of the mark or space is arbitrarily changed for the use thereof.
All the marks or spaces that range 2T to 4T or longer as well as the front edge and rear edge thereof are not necessarily needed for the processing, and specific values may be suitably used. These transient equalization errors may be used in a form that is easy to handle after the arithmetic processing thereof to obtain an average or variance thereof. In consideration of the circuit operation in an actual processing, those values may be used in a chronological order; however, use of the integral or average of those values over a fixed period allows the tendency of the recorded state to be judged with ease, thereby facilitating the recognition processing, correspondence processing, etc.
The level-value recognition unit (
The level-value recognition unit 45 recognizes whether the reproduced signal waveform corresponds to the mark or space on the optical information recording medium based on the level-value or transition of the level-value of the reference reproduced-waveform. In an alternative, the level-value recognition unit 45 recognizes whether the reproduced waveform corresponds to the front edge or rear edge of the mark or space on the optical information recording medium for the transition of the level-value of the reference reproduced-waveform (step B300). The transient-equalization-error detector 44 extracts the transient equalization error that is classified as the front edge or rear edge in accordance with the state as to whether the reproduced waveform is the mark or space, or the transition state as to whether it is a transition from the space to the mark or a transition from the mark to the space, that is recognized by the level-value recognition unit 45 from the equalization error information calculated by the equalization-error calculation unit 43 (step B400). The transient equalization error extracted is used as the quality index showing the positional deviation of the recorded mark.
The level-group recognition unit 46 stores therein, as the level group, the transition pattern of the level-value within a plurality of channel clocks until the reproduced signal waveform assumes the specific level-value, and the transition pattern of the level-value within a plurality of channel clocks after the reproduced signal reaches the specific level-value. The level-group recognition unit 46 stores, as the level group, transition of the level-value within (n−1)T clocks, for example, with respect to a record length of nT (n is a natural number) for the recorded mark or the recorded space to be detected. The level-group recognition unit 46 monitors transition of the level-value of the reproduced signal waveform, to detect a transition pattern that matches one stored in the level group.
The level-values obtained by performing the PR12221 equalization onto patterns 2T-8T of (1,7) RLL include nine values having nine levels, and the reproduced signal waveform (reference reproduced-waveform) assumes level-values of 0-8, as shown in
In the case of PR12221, the correspondence of the recorded mark or space at the level-value “4” is determined by the relationship with respect to the value ahead or behind the-level value “4”. The level-group recognition unit 46 classifies the level-value “4”, for example, by using the level group wherein the level-value assumes 2→3→4 (path of S6 →S1→S2→S4 in the state transition diagram of
Next, a case is considered where the level-value “3” in the 4T pattern, i.e., n is equal to 4 in the nT pattern, is to be judged. With reference to
Similarly, a case is considered where the level-value “5” in the 4T pattern is to be judged. This level-value “4” exists in the 5T, 6T, 7T, and 8T other than the 3T. Comparing these patterns in the transition of level-value before the time instant of level-value “5” including the same time instant, the transition advances along “7”, “7”, and “5” in the 4T pattern, whereas the transition advances along “7”, “8”, “7”, and “5” in the 5T pattern, and along “7”, “8”, “8”, “7”, and “5” in the 6T pattern, whereby the way of transition is different between the patterns. Since the level-value higher than “4” corresponds to the recorded mark, use of the level group of “7”, “7”, and “5” allows recognition of the level-value “5” corresponding to the 4T mark.
In the above description, the nT mark or space is recognized using the level group including transition of level-value within (n−1)T clocks. However, a variety of cases may be classified corresponding to the recorded marks or recorded spaces, so long as the transition of level-value in the level group is not limited to that within the (n−1)T clocks. Preparation of level groups corresponding to other level-values ahead or behind the specific level-value, if any, allows classification of the marks or spaces ahead or behind the specific level-value, whereby a detailed classification such as the nT mark or space succeeding to a mT mark or space, or a mT mark or space succeeding to an nT mark or space (m is an integer) may be possible. It is to be noted that m and n satisfy m>1 and n>1 in the (1,7) RLL.
For example, a case is considered wherein a 3T mark and a 4T or longer mark are classified therebetween, when provided ahead or behind a 2T space (level-value “4”). The following four level groups are prepared:
2,3,4,4,3,2;
2,3,4,4,3,1;
1,3,4,4,3,2; and
1,3,4,4,3,1.
In this case, use of the level group “2,3,4,4,3,2” provides recognition of the level-value “4” in the case of sequential arrangement of a 3T mark, a 2T space and a 4T or longer mark. Use of the level group “2,3,4,4,3,1” provides recognition of the level-value “4” in the case of sequential arrangement of a 3T mark, a 2T space and a 4T or longer mark. Use of the level group “1,3,4,4,3,2” provides recognition of the level value “4” in the case of sequential arrangement of a 4T or longer mark, a 2T space and a 3T mark, and use of the level group “1,3,4,4,3,1” provides recognition of the level-value “4” in the case of sequential arrangement of a 4T or longer mark, a 2T space and a 4T or longer mark.
The result of recognition by the level-group recognition unit 46 shows which combination of the marks and spaces the level-value of the reproduced signal waveform at the time instant of obtaining the transient equalization error corresponds. The transient-equalization-error detector 44 classifies the transient equalization error for each recognized combination based on the result of recognition by the level-group recognition unit 46.
The level-group recognition unit 46 judges using the level group which combination of the marks and spaces the level-value of the reference reproduced-waveform at the time instant of obtaining the transient equalization error corresponds (step C300). The transient-equalization-error detector 44 classifies the combination of the marks and spaces based on the result of recognition by the level-group recognition unit 46, to extract the transient equalization error (step C400). The transient equalization error thus extracted is used as the quality index showing the positional deviation of the recorded mark.
Hereinafter, the advantages will be described using the results of investigation performed until the present invention could be accomplished. Two conditions (condition-1 () and condition-2(
)) are considered that provide different recording positions to the 2T mark shown in
) and condition- 2 (
), under which the 2T mark, i.e., the shortest mark, is formed at different positions while using a power ratio of 1.
The average (Ave) means the average of the value of the front edge and rear edge of each pattern. In
Comparing the condition-1 (
Verification was performed as to whether the quality of the recorded mark can be improved by the recording control so as to reduce the transient equalization error a whether or not the recording control is applicable in the case of raising the recording density by using another type of disc medium for which a different process is used for forming the recorded mark (rewritable-type phase change medium). The optical head used herein was one that had a numerical aperture, NA, of 0.65 for the objective lens, and a LD wavelength, λ, of 405 nm, similarly to that described above, and the optical disc used was one that had a diameter of 120 mm, a polycarbonate substrate which had a substrate thickness of 0.6 mm, and on which a guide groove for a land/groove format was formed. The density of recorded data was such that the bit pitch was 0.13 μm, and the track pitch was 0.34 μm, and the recording film used was a phase-change recording film (rewritable type) for which recording is performed by phase change.
A smaller value of the transient equalization error corresponds to a smaller deviation, whereby the condition that provides a uniform transient equalization error and a transient equalization close to the reference (target) transient equalization error for the mark or space is equivalent to the condition that allows an excellent recording. This condition corresponds to the integrated value 2T_SUM () being close to zero.
The trial of the balancing calibration is performed by recording/reproducing under the condition of 2Tsfp=0.90 due to the constraint of the setting accuracy of Tsfp, to calculate the transient equalization error and measure the PRSNR at the same time.
As described heretofore, it was confirmed that the positional deviation of the recorded mark can be detected with a higher degree of accuracy by using the transient equalization error as a performance index of the signal quality, and that a high-quality recorded mark can be obtained comprehensively by controlling the recording while calibrating the waveform so as to reduce the transient equalization error. It was also confirmed that this technique can be used to other types of the disc medium for which the recorded mark is formed by different processes, and can be applied in the case of further raising the recording density, to thereby show the validity of this technique.
The present inventors also found that the shortest mark or shortest space or the mark or space having one recording length (one channel clock) longer than the shortest mark or shortest space incurs a significant influence on the recording/reproducing performance, in the case of such a higher recording density that the performance cannot be assured without using the PRML detection.
In
As described above, the present invention allows detection of the positional deviation of the recorded mark with a higher degree of accuracy, which is recorded at a higher recording density on an optical information recording medium. This is because the detection of positional deviation of the recorded mark is suited to the higher-density recording/reproducing/detecting technique The present invention achieves also the advantage that a high-quality mark can be formed in a high density recording due to employing a suitable recording condition that can increase the margin. This is because the positional deviation (error) of the recorded mark recorded in a high density recording is detected with a higher degree of accuracy, which allows control of the recording condition to reduce the positional deviation of the recorded data.
The present invention provides a higher-speed calibration of the recording condition prior to actual recording of information. This is because all the parameters need not be necessarily optimized by measuring the margin for respective parameters, and because correction of the positional deviation of the recorded mark recorded at a higher density can be performed efficiently without waste of time and thus calibration of the recording condition can be performed at a higher speed, by detecting the positional deviation of the recorded mark with a higher degree of accuracy for quantization thereof. In the present invention, a large area is not needed for optimization of the parameters because all the parameters need not be optimized by measuring the margins for the respective parameters, and the positional deviation of the recorded mark can be accurately corrected by accurately detecting the positional deviation of the recorded mark recorded by a higher density recording. This suppresses use of a wasted area and reduces the waste of the calibration area upon calibration of the recoding condition.
The present invention allows formation of the recorded mark more adapted to a higher-density recording/reproducing/detecting technique that is used to reproduce a mark recorded by a higher density recording. This is because the positional deviation of the recorded mark adapted to the higher-density recording/reproducing/detecting technique is detected and used for control of the recording condition under which the mark is to be formed. The configurations of the signal-quality detector shown in
Hereinafter, the description will be given by using examples.
The optical information recording/reproducing unit used in this example was one having a NA of 0.65 for the objective lens in the optical head and a LD wavelength, λ, of 405 nm. The signal-quality detector used therein was the signal-quality detector 40a of the second exemplary embodiment shown in
The signal-quality detector 40a classified the front edge and rear edge of each of the 2T, 3T, and 4T or longer marks or spaces, and the transient-equalization-error detector 44 extracted (calculated) the transient equalization errors that are classified into these items. The optical information recording medium used herein was an optical information recording medium having a substrate thickness of 0.6 mm, and a bit pitch of 0.153 μm and a track pitch of 0.4 μm as the data density for recording. A write-once optical information recording medium was used herein having a recording film including organic dye and no identification code showing the disc manufacturer.
Generally, upon loading a typical optical disc onto an optical information recording/reproducing unit, the optical information recording/reproducing unit judges the type of the optical disc, and distinguishes the manufacturer thereof. Since the optical disc used in the example-1 has no record of the identification code information of the manufacturer, the disc was handled as an unknown disc. The optical information recording/reproducing unit, after calibrating the servo parameters, read the fundamental strategy that determines the recording laser pulse shape as one of the recording condition parameters, set the same on the LD drive circuit 13 (
The optical information recording/reproducing unit, upon judging that calibration of the recording condition is insufficient, performed recording under the recording condition CT5 while further changing the laser pulse shape, and reproduced the recorded area similarly to the case as described above, to measure (calculate) the transient equalization error, average value Ave, and integrated value SUM corresponding to the front edge and rear edge of the mark or space of 2T pattern, 3T pattern, and the 4T or longer pattern.
In order to verify the validity of the above calibration, a margin of the conditions CT4 and CT5 was measured on the tilt of the optical head upon recording in the radial direction with respect to the optical disc.
The optical information recording/reproducing unit used in this example was the same as that used in the first example, and had a NA of 0.65 for the objective lens, and a LD wavelength, λ, of 405 nm. The optical disc used was one having a substrate thickness of 0.6 mm, and a bit pitch of 0.13 μm and a track pitch of 0.34 μm as the recorded data density. The recording film of the optical disc used was a phase-change recording film that performs recording based on the phase change thereof, and thus is of a rewritable type. The recording/reproducing data on the optical disc was performed by the ECC. The configuration was such that the signal-quality detector used herein was the signal-quality detector 40 in the first exemplary embodiment, “4” is employed as the specific level-value in the signal-quality detector 40, and the transient-equalization-error detector 44 calculated the transient equalization error of the 2T pattern.
The controller 50, upon loading of the optical disc onto the optical information recording/reproducing unit, judged the type of optical disc, set the waveform which was calibrated in advance for record compensation, moved the PUH 10 to the specific position, and performed recording while changing the recording power. The controller 50 then reproduced the recorded mark, and performed selection of a suitable power based on the transient equalization error. A recording power was obtained that causes the total value of the transient equalization error (transient equalization error calculated for the mark and space and for the front edge and rear edge and obtained without classification) to approach zero (target), wherein a laser power of Pw=1 was selected as the suitable recording power.
In the present example, the transient equalization error was calculated by the signal-quality detector 40 shown in
The optical information recording/reproducing unit used in the present example was the same as that used in the first example. The optical disc used herein had a bit pitch of 0.13 μm and a track pitch of 0.34 μm as the data density for recording, and included a phase-change recording film that performs recording by the phase change thereof. The optical disc used in the present example was a disc of a rewritable type (HLRW disc), wherein recording of the mark reduces the reflectance. Recording/ reproduction of data is performed by the ECC. The signal-quality detector used herein was a type of the signal-quality detector 40a used in the second exemplary embodiment and shown in
The controller 50, upon loading of the optical disc onto the optical information recording/reproducing unit, judged the type of the optical disc and recognized the same as the HLRW disc. The optical information recording/reproducing unit read out the correlation shown in
The controller 50 obtains which power ratio the recording corresponds, thereafter sets the recording power so that the recording is performed at a power ratio (0.95) that is the target position shown by o in
The optical information recording/reproducing unit used in the present example was the same as that used in the first example. The optical disc used herein was a write-once disc having a substrate thickness of 0.6 mm, a bit pitch of 0.153 μm and a track pitch of 0.4 μm as the density for recorded data, and including an organic dye for the recording film. The signal-quality detector used herein is the signal-quality detector 40a in the second exemplary embodiment shown in
The recording is first performed under the calibration condition A1, and the data is then reproduced to calculate the transient equalization error. The transient equalization errors obtained at the front edge and rear edge of the mark and space of each pattern are those shown in
The controller 50 refers to the transient equalization error (
The controller 50 recognizes that the 2T is turned into a positive value with reference to the transient equalization error under the condition A3 (
The controller 50 recognizes that the 3T is turned into a positive value with reference to the transient equalization error under the condition A4 (
The controller 50 recognizes that there is no trouble state, with reference to the transient equalization error (
It is known that the PRSNR should assume around 20 or above including the device margin. The PRSNR already exceeds 25 at the initial stage of calibration, and thus there is substantially no trouble on the reproduction even without changing the PRSNR. However, the total device margin is likely to be reduced due to a variety of factors in the case of handling a large number of devices. Thus, as shown in the present example, it is highly desirable that the respective margins have a sufficient excessive margin. The validity of the present example could be assured by the capability of improving the PRSNR up to a value of 39, even in the case where the PRSNR already exceeds 25, by later calibrating the pulse waveform parameters of the respective patterns based on the transient equalization error.
The optical information recording/reproducing unit used in the present example had a NA of 0.65 for the objective lens in the optical head and a LD wavelength, λ, of 405 nm, similarly to the first example. The optical disc used herein was a write-once disc having a substrate thickness of 0.6 mm, a bit pitch of 0.153 μm and a track pitch of 0.4 μm as the data density for recording, and including an organic dye in the recording film. The optical information recording/reproducing unit included a storage section 80 (
The optical information recording/reproducing unit, upon loading of the optical disc thereto, read out the identification information of the manufacturer of the thus loaded optical disc and judged that the disc was one manufactured by the disc manufacturer A. The optical information recording/reproducing unit moved the PUH 10 (
The recorded pattern recorded in the drive test zone was such that the seed of M-sequence belongs to the same random pattern. The random pattern recorded in the ECC blocks is the same pattern. The recorded pattern is saved in the storage section 80. The reference-waveform generation unit 42 (
The optical information recording/reproducing unit used in the present example had a NA of 0.65 for the objective lens in the optical head and a LD wavelength, λ, of 405 nm, similarly to the first example. The optical disc used herein was a write-once disc having a substrate thickness of 0.6 mm, and a bit pitch of 0.153 μm and a track pitch of 0.4 μm as the density of recorded data, and included an organic dye in the recording film. The signal-quality detector used herein was the signal-quality detector 40b in the third exemplary embodiment shown in
The controller 50 (
With reference to
As described heretofore, according to the present invention, it is possible to detect, with a higher degree of accuracy, the positional deviation of the recorded mark recorded with a higher density, whereby formation of a higher-quality recorded mark having a larger margin can be achieved. Upon calibration of the recording condition, it is possible to achieve the advantage of a higher-speed calibration without involving waste of the calibration area. The present invention also provides a method of measuring the signal quality of the recorded mark suitable for a higher-density recording/reproduction, thereby allowing formation of the recorded mark more suitable for the higher-density recording/reproduction.
The reproduction/detection technique for a high-density-recorded mark as typified, in particular, by the PRML may include a conventional level-slice detection technique. Thus, it is apparent that the technique of the present invention can be applied to the PRML detection technique even if it is applied to such a recording density that allows detection by the level-slice detection technique. The NA related to the beam diameter in the configuration of the optical head is not limited to 0.65, and the present invention may be applied as well to a system having a NA of 0.85 and thus forming a smaller recorded mark.
In the above description, the PR12221 is exemplified; however, quality measurement of the recorded mark and calibration of the recording condition can be performed in a similar way for other PR classes. Hereinafter, a case will be described where PR 1221 is used.
In the PR12221, the reference reproduced-waveform is classified into nine levels (
In the case of PR1221, the transient equalization error is calculated at the specific level-value, for example, the central level-value “3” selected from among the levels of “0” to “6”. More specifically, among the equalization errors that are obtained as the difference between the reproduced signal waveform and the reference reproduced-waveform, an equalization error obtained at the level “3” upon transition of the level thereto from another level at one or two channel clocks before or upon transition of the level therefrom to another level at one or two channel clocks after is selected as the transient equalization error. The following table 3 shows the transient equalization errors at the front edge and rear edge of each mark length or space length, similarly to table 1.
As described before, as to the correspondence of the mark and space, optical information recording media include one wherein the reflectance changes from low to high along with a change from a non-recorded state to a recorded state, and another wherein, to the contrary, the reflectance changes from high to low along with a change to a recorded state. Although the correspondence of the mark and space may be reversed depending on the medium used therein, this can be handled by suitably changing the signal processing etc. depending on the type of the medium.
As to 2T in the PR1221, the front edge and rear edge can be distinguished based on the transition from the level at one channel clock before or after; however, as to 3T and 4T (or above), the level transition may be same as the transition at one channel clock before or after, unlike the PR12221. For example, for both the front edge of 3T (LH 3TF) and front edge of 4T (or above) (LH 4TF), the level ahead the level “3” is level “5”. The transition of HL 3TF and HL 4TF, the transition of LH3TR and LH 4TR and the transition of HL 3TR and HL4TR are the same for each two, similarly to the above case. Thus, the level at two channel clocks before or after is used herein for classifying the each two. The “level at two channel clocks before” as to the LH 3TR is “5” and that as to the LH 4TF is “6”. Therefore, if the transition advances 5→5→3, LH 3TF is recognized, whereas if the transition advances 6→5→3, LH 4TF is recognized. As to the other cases, observation of the transition within two channel clocks before or after provides recognition of the front edge and rear edge of 3T and 4T (or above).
Next, the difference in the interval of the transient equalization error depending on the difference in the PR class will be described. In the PR 1221, since the transition from the mark to space and from the space to mark involves the central level “3” without fail, the timing of detection of all the transient equalization errors uses the transition equalization error at the timing of level “3”. For this reason, the front edge of “aT” is the same as the rear edge of “bT”, and the rear edge of “aT” is the same as the front edge of “cT” (a, b, and c are each integer equal to 2, 3, 4 or above). That is, the front edge and rear edge in the PR 1221 are in a strong association with each other. The overlapping of the calculation timing of the transient equalization error between the front edge and the rear edge renders the interval between adjacent transient equalization errors equal to the interval corresponding to the recorded length. For example, in the 3T mark, the transient equalization error corresponding to the rear edge is obtained at three channel clocks after the transient equalization error corresponding to the front edge thereof.
On the other hand, in the PR 12221, the transient equalization errors are classified into six transient equalization errors corresponding to the front edge and rear edge of 2T, front edge and rear edge of 3T, and front edge and rear edge of 4T or longer, and the patterns other than 2T pattern do not assume the central level “4”, and have respective independent levels. More specifically, the PR 12221 allows the front edges and rear edges to be independent from one another. As described before, since the same level (level “3”) is used in the PR 1221 for both the mark and space, the transient equalization errors thereof are in association with one another, whereas since different levels are used in the PR12221 for the mark and space, the transient equalization errors thereof are independent from one another. In any of these transient equalization errors, the improvement of performance can be obtained by adjusting the deviation (balance) of the transient equalization errors with respect to the target.
Independent transient equalization errors may also be used in the PR1221, or transient equalization errors in association with one another may also be used in the PR12221. Although the six transient equalization errors in the PR12221 are independent between the front edge and the rear edge, with one channel clock disposed therebetween, a value of (front edge+rear edge)/2 may be used for the transient equalization error, to obtain mutual association between the transient equalization errors.
Next, considering the transition from the 2T mark to the 3T space in
In the PR1221, the equalization error obtained at the level “3” and the equalization error at one channel clock before or after may be averaged to obtain a transient equalization error, and six independent transient equalization errors may be obtained in this way.
As described above, use of the six transient equalization errors in association with one another the PR1221 and use of the six independent transient equalization errors will also improve the performance, so long as the importance of balance is considered.
The present invention achieves the advantages as described hereinafter.
An optical information recording/reproducing unit according to a preferred embodiment of the present invention calculates, as a transient equalization error, a difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value group at m channel clocks (m is an integer not less than one) before or after the time instant of the specific level-value satisfy therebetween a specific relationship. For example, with the specific level-value being assumed at “4”, a difference between the reference reproduced-waveform and the equalized reproduced waveform at the time instant of transition from another level-value to the level-value “4” or at the time instant of transition from the level-value “4” to another level-value and the reference reproduced-waveform is calculated as the transient equalization error. The transient equalization error obtained in this way assumes a value corresponding to the positional deviation of the recorded mark, and thus can be used as a quality index of the positional deviation of the recorded mark. Since the positional deviation of the recorded mark is detected by a technique suitable to the higher-density recording in the optical information recording/reproducing unit of the present invention, the positional deviation of the recorded mark formed with a higher-density recording technique can be detected with a higher degree of accuracy.
A method for measuring a recorded mark quality of an optical information recording-reproducing unit according to a preferred embodiment of the present invention calculates, as a transient equalization error, a difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value group at m channel clocks (m is an integer not less than one) before or after the time instant satisfy therebetween a specific relationship. Since the method of measuring the recorded mark quality of the present invention detects the positional deviation of the recorded mark by using a technique suited to a higher-density recording, the positional deviation of the recorded mark recorded with a higher density on the medium can be detected with a higher degree of accuracy.
A record controlling method according to a preferred embodiment of the present invention calculates, as a transient equalization error, a difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value group at m channel clocks (m is an integer not less than one) before or after the time instant satisfy therebetween a specific relationship, and controls the shape of a recording laser pulse that irradiates the optical information recording medium upon data recording so that the transient equalization error decreases. The transient equalization error represents the quality of the recorded mark formation, and control of the recording condition by using the transient equalization error so as to improve the quality of recorded mark allows superior recording/reproduction.
The following description comprehensively discloses the preferred embodiments of the present invention.
The optical information recording/reproducing unit according to the present invention may employ a configuration wherein the reference-waveform generation section generates the reference reproduced-waveform by applying the specific response characteristic to an estimated data train estimated based on the reproduced signal waveform. In an alternative, a configuration may be employed wherein the reference-waveform generation section reads out a recording data train recorded on the optical information recording medium from a storage unit, and generates the reference reproduced-waveform by applying the specific response characteristic to the recording data train. A configuration may be employed wherein a recording data train corresponding to the reproduced signal waveform is estimated based on the reproduced signal waveform and used upon generation of the reference reproduced-waveform. In an alternative, a configuration may be employed wherein the data recorded on the medium is stored in a storage section and the reference reproduced-waveform is generated with reference thereto.
The optical information recording/reproducing unit according to the present invention may employ a configuration wherein the reproduced signal waveform and the reference reproduced-waveform are each continuous waveform that has a level-value at each channel clock corresponding to the recorded mark or space recorded on the optical information recording medium.
The optical information recording/reproducing unit according to the present invention may further includes a level-value recognition section that judges, based on a level-value of the reference reproduced-waveform or a transition of the level-value of the reference reproduced-waveform, which of the recorded mark and space or which of a front edge and a rear edge on the optical information recording medium the level-value of the reference reproduced-waveform corresponding to the time instant at which the transient equalization error is obtained corresponds, and may have a configuration wherein the transient-equalization-error calculation section classifies the transient equalization error based on results of the recognition by the level-value discrimination section. In this case, since the level-value recognition section judges whether the specific level-value at the time instant of calculating the transient equalization error corresponds to the mark or space, the transient equalization error can be specified as the mark or space. In addition, by judging whether the transition is a transition from the specific level-value or a transition to the specific level-value, the transient equalization error can be classified corresponding to the front edge and the rear edge of the mark or space.
The optical information recording/reproducing unit according to the present invention may further include level-group recognition section that stores therein a level transition pattern within of a plurality of channel clocks before and/or after the time instant at which the reference reproduced-waveform assumes the level-value, as a level group corresponding to a mark or space having a specific recorded length, and judges based on the level group which of a mark and a space the level-value of the time instant at which the transient equalization error is obtained corresponds, and may have a configuration the transient-equalization-error calculation section classifies the transient equalization error based on a result of judgment by the level-group recognition section. In this case, classification of the transition into detailed classification by using the level group allows the transient equalization error to be classified into combinations of the mark and space having a variety of recorded length.
The optical information recording/reproducing unit according to the present invention may employ a configuration wherein the transient-equalization-error calculation section calculates at least one of a transient equalization error corresponding to a shortest mark or space on the optical information recording medium or another mark or space that is one channel clock longer than the shortest mark or space, and a transient equalization error corresponding to a front edge or rear edge of the shortest mark or space or the another mark or space that is one channel clock longer than the shortest mark or space.
The optical information recording/reproducing unit according to the present invention may further includes a recording-condition control section that controls the shape of a recording laser pulse that irradiates the optical information recording medium upon data recording so that the transient equalization error decreases. By using the transient equalization error as the quality index showing the quality of the recorded mark formation to set the recording condition so as to improve the quality of recorded mark formation, superior recording/reproduction can be obtained.
The optical information recording/reproducing unit according to the present invention may employ a configuration wherein the recording-condition control section controls the shape of the recording laser pulse by changing at least one of a starting position or ending position and a waveform shape of the recording laser pulse for each recording mark, to thereby change a position of the recorded mark or space, so that the transient equalization error decreases. By performing recording while changing the recording condition, reproducing the recorded data to obtain the transient equalization error and adaptively calibrating the recording condition so as to reduce the thus obtained transient equalization error, a recording condition allowing a superior recording/reproduction can be obtained.
The method for measuring a recorded-mark quality of an optical information recording medium according to the present invention may employ a configuration wherein the reference-waveform generating reads out a recording data train recorded on the optical information recording medium from a storage unit, and generates the reference reproduced-waveform by applying the specific response characteristic to the recording data train.
The method for measuring a recorded-mark quality of an optical information recording medium according to the present invention may employ a configuration wherein the reproduced signal waveform and the reference reproduced-waveform are each continuous waveform that has a level-value at each channel clock corresponding to the recorded mark or space recorded on the optical information recording medium.
The method for measuring a recorded-mark quality of an optical information recording medium according to the present invention may further includes: judging, based on a level-value of the reference reproduced-waveform or a transition of the level-value of the reference reproduced-waveform, which of the recorded mark and space or which of a front edge and a rear edge on the optical information recording medium the level-value of the reference reproduced-waveform corresponding to the time instant at which the transient equalization error is obtained corresponds, and classifying the transient equalization error based on a result of the recognition in the judging. In this case, since it is judged whether the specific level-value at the time instant of calculating the transient equalization error corresponds to the mark or space, the transient equalization error can be specified as the mark or space. In addition, by judging whether the transition is a transition from the specific level-value or a transition to the specific level-value, the transient equalization error can be classified corresponding to the front edge and the rear edge of the mark or space.
The method for measuring a recorded-mark quality of an optical information recording medium according to the present invention may further includes: storing a level transition pattern within of a plurality of channel clocks before or after the time instant at which the reference reproduced-waveform assumes the level-value, and judging, based on a level group corresponding to a mark or space having a specific recorded length, which of a mark and space the level-value of the time instant at which the transient equalization error is obtained corresponds; and classifying the transient equalization error based on a result of judgment in the judging. In this case, classification of the transition into detailed classification by using the level group allows the transient equalization error to be classified into combinations of the mark and space having a variety of recorded length.
The method for measuring a recorded-mark quality of an optical information recording medium according to the present invention may employ a configuration wherein the transient-equalization-error calculating calculates at least one of a transient equalization error corresponding to a shortest mark or space on the optical information recording medium or another mark or space that is one channel clock longer than the shortest mark or space, and a transient equalization error corresponding to a front edge or rear edge of the shortest mark or space or the another mark or space that is one channel clock longer than the shortest mark or space.
The record controlling method for an optical information recording medium according to the present invention may further include controlling the shape of the recording laser pulse by changing at least one of a starting position or ending position and a waveform shape of the recording laser pulse for each recording mark, to thereby change a position of the recorded mark or space, so that the transient equalization error decreases.
According to the optical information recording/reproducing unit, method for measuring the quality of recorded mark on an optical information recording medium and the recording control method of the present invention, calculation of the difference between the reference reproduced-waveform and the reproduced signal waveform at a time instant at which the reference reproduced-waveform assumes a specific level-value and at which the specific level-value and a level-value (level-value group) at m channel clocks (m is an integer not less than one) before or after the time instant of the specific level-value satisfy therebetween a specific relationship is performed to obtain the transient equalization error. This transient equalization error can be used as a quality index of the positional deviation of the recorded mark formation. In the present invention, since the positional deviation is detected using a technique that is suited to a higher density recording, the positional deviation of the recorded mark recorded on the medium with a higher density can be detected with a higher degree of accuracy. In addition, control of the recording laser pulse shape so as to reduce the transient equalization error allows a superior recording/reproduction.
While the present invention has been described based on the preferred embodiments thereof, the optical information recording/reproducing unit, method for measuring the quality of recorded mark on an optical information recording medium and the recording control method of the present invention are not limited only to the above embodiments, and a variety of modifications and alterations from the above embodiments may fall within the scope of the present invention.
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2006-245236, field on Sep. 11, 2006, the entire contents of which are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-245236 | Sep 2006 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2007/067648 | 9/11/2007 | WO | 00 | 3/4/2009 |
