JP2011054240A - Optical disk recording and reproducing device and optical disk recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve recording quality by properly correcting recording strategy. <P>SOLUTION: A system controller 7 changes a duty ratio of a recording pulse train with respect to the recording strategy so that a modulation degree of a reproduction signal of data written on trial with an optimal recording power required by OPC processing is equal to or greater than a threshold, and improves edge shift by changing the timing of an edge of the recording pulse train for the recording strategy with corrected duty ratio so that a jitter of the reproduction signal of the data written on trial using the recording strategy with corrected duty ratio becomes equal to or lower than the threshold. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical disc recording / reproducing apparatus and an optical disc recording method for recording on an optical disc.

  In general, in an optical disk recording / reproducing apparatus, a recording operation on a recordable optical disk such as a BD-R (Blu-ray Disc Recordable), a BD-RE (Blu-ray Disc Rewritable), and a DVD-R (Digital Versatile Disk Recordable) is performed. Prior to this, OPC (Optimum Power Control) processing is performed so that a recording pulse having an optimum recording power in a predetermined recording strategy can be generated. The recording strategy refers to a control rule for the recording pulse.

  Usually, the recording strategy is registered in advance in the optical disc recording / reproducing apparatus for each optical disc ID. The optical disc recording / reproducing apparatus reads out a recording strategy corresponding to the optical disc to be recorded from the registered recording strategy and adopts it.

  When recording on an unknown disc that is not registered in the optical disc recording / reproducing device, the optical disc recording / reproducing device reads disc information from the optical disc (unknown disc), and this disc information The recording strategy included in is adopted.

  However, the recording strategy included in the disc information corresponds to the case where recording is performed under the recording conditions defined in the optical disc standard, and generally differs from the recording conditions of the optical disc recording / reproducing apparatus. The optimum recording pulse edge position of the recording strategy may vary due to such a difference in recording conditions. If the pulse edge position of the recording pulse is not appropriate, the mark length or edge position of the recording mark recorded on the optical disc is out of the appropriate range, and the reproduction quality of information such as jitter characteristics is deteriorated during reproduction. For this reason, it may be necessary to correct the recording strategy read from the unknown disk.

  As a technique for correcting the recording strategy, for example, there are techniques described in Patent Documents 1 to 3.

  In the technique of Patent Document 1, first, disk information is read from an optical disk (unknown disk) to be recorded, and an OPC process is executed using a recording strategy included in the disk information to obtain an optimum recording power. Next, trial writing is performed with the obtained optimum recording power using the recording strategy included in the disc information, and the edge shift amount of the recording mark, the jitter of the reproduction signal, based on the reproduction signal obtained by reproducing the trial written data, Measure.

  If the jitter exceeds a predetermined threshold, the recording strategy is corrected so as to improve the edge shift, test writing is performed with the optimum recording power using the corrected recording strategy, and the edge shift amount and the jitter are calculated. taking measurement. Until the jitter of the reproduction signal falls below the threshold, the correction of the recording strategy for improving the edge shift and the trial writing are repeated, and the recording strategy at which the jitter is below the threshold is determined as the recording strategy used for the optical disc to be recorded. .

  Patent Document 2 also discloses a method for measuring the edge shift amount of a recording mark formed based on a set recording strategy and calculating the sensitivity of the edge shift amount of the recording mark with respect to the edge correction amount of the recording pulse. A technique for calculating a simple recording strategy is disclosed.

  Patent Document 3 discloses a technique for calculating a suitable recording strategy by calculating an optimum recording pulse width from a β value that is a parameter indicating the asymmetry of a reproduction signal of a test-written signal. .

JP 2008-103017 A JP 2007-226916 A JP 2005-149610 A

  When the modulation degree of the reproduction signal of the data recorded with the optimum recording power obtained by the OPC process is small, the jitter of the reproduction signal becomes large even if the edge position of the recording mark is appropriate. Therefore, in such a case, even if the recording strategy is corrected by the technique as described in Patent Documents 1 to 3 to improve the edge shift, the jitter characteristic of the reproduction signal cannot be improved, and the recording quality is sufficiently improved. I could not.

  The present invention has been made in view of the above, and an object of the present invention is to provide an optical disc recording / reproducing apparatus and an optical disc recording method capable of improving the recording quality by appropriately correcting the recording strategy.

  According to one aspect of the present invention, optimal recording for the main recording of the optical disc is performed from a reproduction signal obtained by performing trial writing on the optical disc with a plurality of recording powers according to a recording strategy registered in the optical disc and reproducing the trial written data. An optimum recording power calculating means for calculating an optimum recording power as power, a modulation degree calculating means for calculating a modulation degree of a reproduction signal obtained by reproducing data trial-written on the optical disc, and a duty of a recording pulse train corresponding to the recording strategy Optimal when the modulation ratio of the reproduction signal corresponding to the optimum recording power calculated by the optimum recording power calculation means is smaller than a predetermined modulation degree threshold, and the duty ratio correction means for correcting the recording strategy so as to change the ratio The duty ratio compensation is performed until the modulation level of the reproduction signal corresponding to the recording power becomes equal to or higher than the modulation level threshold. After correcting the recording strategy so as to change the duty ratio of the recording pulse train by means, the process of calculating the optimum recording power by the optimum recording power calculation means according to the corrected recording strategy after changing the duty ratio is repeated. The optimum recording power is calculated with the optimum recording power calculated by the duty ratio correction control means and the optimum recording power calculation means, and the modulation degree of the reproduction signal of the test-written data is not less than the modulation degree threshold value. Test writing means for performing trial writing on the optical disc in accordance with the recording strategy used in the optimum recording power calculation means, and each recording mark recorded on the optical disc from a reproduction signal of data trial-written by the trial writing means. Edge shift amount measuring means for measuring the edge shift amount of Jitter measuring means for measuring jitter of a reproduction signal of data written by trial writing by a writing means, and pulse edge timing for correcting the recording strategy so as to change the timing of the edge of the recording pulse train in order to reduce the edge shift amount When the jitter measured by the correcting means and the jitter measuring means is greater than a predetermined jitter threshold, the recording is performed by the pulse edge timing correcting means until the jitter measured by the jitter measuring means is less than or equal to the jitter threshold. After correcting the recording strategy so as to change the timing of the edge of the pulse train, control is performed so as to repeat the process of performing the trial writing by the test writing means according to the corrected recording strategy of changing the edge timing of the recording pulse train Pulse edge timing correction control hand And a recording strategy in which a jitter of a reproduction signal of data trial-written by the trial writing means is equal to or less than the jitter threshold is determined as a recording strategy used by the optical disc recording / reproducing apparatus for the optical disc, and the recording strategy is determined. There is provided an optical disc recording / reproducing apparatus comprising recording strategy determining means for writing to the optical disc.

  According to another aspect of the present invention, a test writing is performed on the optical disc with a plurality of recording powers according to a recording strategy registered on the optical disc, and the optimum recording for the main recording of the optical disc is performed from a reproduction signal obtained by reproducing the trial written data. The optimum recording power calculating means for calculating the optimum recording power, which is the recording power, the modulation degree calculating means for calculating the modulation degree of the reproduction signal obtained by reproducing the data written on the optical disc, and the optimum recording power calculating means. When the modulation degree of the reproduction signal corresponding to the optimum recording power is smaller than a predetermined modulation degree threshold, it corresponds to the optimum recording power changing means for changing the optimum recording power and the optimum recording power calculated by the optimum recording power calculating means. When the modulation degree of the reproduction signal is smaller than a predetermined modulation degree threshold, the recording pulse train due to the recording strategy is reduced. A duty ratio correction unit that corrects the recording strategy so as to change the ratio, and an optimum recording power that has been changed by the optimum recording power change unit, and the optical disc is tested according to the recording strategy that has been corrected by the duty ratio correction unit. Trial writing means for writing, edge shift amount measuring means for measuring an edge shift amount of each recording mark recorded on the optical disc from a reproduction signal of data trial-written by the trial writing means, and the trial writing Jitter measuring means for measuring jitter of a reproduction signal of data written by trial writing by means, and pulse edge timing correction for correcting the recording strategy so as to change the timing of the edge of the recording pulse train in order to reduce the edge shift amount And the jitter measured by the jitter measuring means is a predetermined jitter. The recording strategy is corrected so that the edge timing of the recording pulse train is changed by the pulse edge timing correction means until the jitter measured by the jitter measurement means is less than or equal to the jitter threshold. Thereafter, pulse edge timing correction control means for controlling to repeat test writing by the test writing means in accordance with the corrected recording strategy by changing the edge timing of the recording pulse train, and test writing by the test writing means A recording strategy in which the jitter of the reproduced signal of the reproduced data is equal to or less than the jitter threshold is determined as a recording strategy used by the optical disc recording / reproducing apparatus for the optical disc, and a recording strategy determining means for writing the recording strategy to the optical disc; With features An optical disc recording / reproducing apparatus is provided.

  According to another aspect of the present invention, a test writing is performed on the optical disc with a plurality of recording powers according to a recording strategy registered on the optical disc, and the optimum recording for the main recording of the optical disc is performed from a reproduction signal obtained by reproducing the trial written data. An optimum recording power calculating step for calculating an optimum recording power that is a recording power, and an optimum recording power when the modulation degree of the reproduction signal corresponding to the optimum recording power calculated in the optimum recording power calculation step is smaller than a predetermined modulation degree threshold value. Correction after changing the duty ratio after correcting the recording strategy so as to change the duty ratio of the recording pulse train according to the recording strategy until the modulation degree of the reproduction signal corresponding to the power becomes equal to or higher than the modulation degree threshold. The duty ratio correction process is repeated for calculating the optimum recording power using the recording strategy later. And the optimum recording power calculated at the optimum recording power calculation step or the duty ratio correction step, and the optimum recording power at which the modulation degree of the reproduction signal of the test-written data is equal to or greater than the modulation degree threshold. A trial writing step for performing trial writing on the optical disc in accordance with the recording strategy used, and a reproduction signal of the data trial-written by the trial writing step, and an edge shift amount and a reproduction signal of each recording mark recorded on the optical disc A measurement step for measuring jitter, and when the jitter measured in the measurement step is greater than a predetermined jitter threshold, the edge shift amount is decreased until the jitter of the reproduction signal of the trial-written data becomes equal to or less than the jitter threshold. In order to change the timing of the edge of the recording pulse train, After correcting the strategy, the pulse edge timing correcting step of repeating test writing according to the corrected recording strategy in which the edge timing of the recording pulse train is changed, and the test trial writing step or the pulse edge timing correcting step And a determination step of determining a recording strategy used for the trial writing in which the jitter of the reproduction signal is equal to or less than the jitter threshold as a recording strategy used by the optical disc recording / reproducing apparatus for the optical disc, and writing to the optical disc. An optical disc recording method is provided.

  According to another aspect of the present invention, a test writing is performed on the optical disc with a plurality of recording powers according to a recording strategy registered on the optical disc, and the optimum recording for the main recording of the optical disc is performed from a reproduction signal obtained by reproducing the trial written data. An optimum recording power calculating step for calculating an optimum recording power that is a recording power, and an optimum recording power when the modulation degree of the reproduction signal corresponding to the optimum recording power calculated in the optimum recording power calculation step is smaller than a predetermined modulation degree threshold value. An optimum recording power changing step for changing power, and a recording pulse train corresponding to the recording strategy when the modulation degree of the reproduction signal corresponding to the optimum recording power calculated in the optimum recording power calculation step is smaller than a predetermined modulation degree threshold value. The duty ratio correction step for correcting the recording strategy so as to change the duty ratio. A trial writing step for performing trial writing on the optical disc in accordance with the recording strategy after the correction by the duty ratio correction step at the optimum recording power after the change in the optimum recording power changing step, and a trial writing by the trial writing step. A measurement step for measuring the edge shift amount of each recording mark recorded on the optical disc and the jitter of the reproduction signal from the data reproduction signal, and when the jitter measured in the measurement step is larger than a predetermined jitter threshold, After correcting the recording strategy so as to change the timing of the edge of the recording pulse train so as to reduce the edge shift amount until the jitter of the reproduced signal of the trial written data becomes equal to or less than the jitter threshold, The corrected recording stroke after changing the edge timing A pulse edge timing correction step that repeats the process of performing test writing according to the stage, and a recording strategy in which the jitter of the reproduced signal is equal to or less than the jitter threshold used in the test writing in the test trial writing step or the pulse edge timing correction step, An optical disc recording method comprising: determining a recording strategy to be used by the optical disc recording / reproducing apparatus for the optical disc and writing to the optical disc.

  According to the optical disc recording / reproducing apparatus and the optical disc recording method of the present invention, it is possible to improve the recording quality by appropriately correcting the recording strategy.

It is a block diagram which shows the structure of the optical disk recording / reproducing apparatus which concerns on embodiment of this invention. It is a block diagram which shows the structure of the recording state detection part of the optical disk recording / reproducing apparatus shown in FIG. It is a wave form diagram which shows an example of the reproduction | regeneration signal from which the direct-current component was cut. It is a figure which shows an example of the recording pulse train of the laser beam comprised according to a recording strategy. FIG. 2 is a diagram showing a combination of a mark length and a space length of a recording mark that can measure an edge shift amount in the optical disc recording / reproducing apparatus shown in FIG. 1. 2 is a flowchart showing an operation of correcting a recording strategy in the optical disc recording / reproducing apparatus shown in FIG. It is a figure which shows the step change of the recording peak power of the laser beam used for an OPC process. It is a figure which shows an example of the modulation | alteration degree of a reproduction signal with respect to recording peak power, and the characteristic of (beta) value. It is a figure which shows the method of the duty ratio correction | amendment of a recording strategy. FIG. 11 is a diagram illustrating recording characteristics when correction for changing a duty ratio is not performed on a recording strategy in an HTL type BD-R. FIG. 11 is a diagram illustrating recording characteristics when correction for changing a duty ratio is performed on a recording strategy in an HTL type BD-R. FIG. 11 is a diagram illustrating recording characteristics when correction for changing a duty ratio is not performed on a recording strategy in an LTH type BD-R. FIG. 6 is a diagram illustrating recording characteristics when correction is performed to change a duty ratio with respect to a recording strategy in an LTH type BD-R. It is a figure which shows an example of the measurement result of edge shift amount when the correction | amendment of a recording strategy is not performed. It is a figure which shows an example of the measurement result of the edge shift amount at the time of performing the correction which changes a duty ratio with respect to a recording strategy. It is a figure which shows an example of the measurement result of the edge shift amount at the time of performing the correction which changes a duty ratio with respect to a recording strategy, and the correction which improves an edge shift. It is a figure which shows an example of the jitter characteristic of a reproduction signal. It is a figure which shows an example of the correlation characteristic of (beta) value and modulation degree in HTL type BD-R. It is a figure which shows an example of the correlation characteristic of (beta) value and modulation degree in LTH type BD-R. It is a figure which shows an example of the correlation characteristic of the amount of correction | amendment of the recording start timing of the recording mark, and (beta) value in HTL type BD-R. It is a figure which shows an example of the correlation characteristic of the amount of correction | amendment of the recording start timing of the recording mark in LTH type BD-R, and (beta) value. It is a flowchart which shows the operation | movement which correct | amends a recording strategy with the optical disk recording / reproducing apparatus which concerns on the modification of embodiment of this invention.

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

  FIG. 1 is a block diagram showing a configuration of an optical disc recording / reproducing apparatus according to an embodiment of the present invention. As shown in FIG. 1, an optical disc recording / reproducing apparatus 1 according to the present embodiment includes an optical pickup 2, a recording / reproducing unit 3, an FEP (front end processor) 4, a recording state detecting unit 5, and reproduction signal processing. A unit 6, a system controller 7, a program memory 8, a data memory 9, an internal bus 10, and an IF (interface) unit 11 are provided.

  The optical pickup 2 records information by irradiating the optical disk 20 with laser light from a laser diode (not shown) as a light source, and receives reflected light from the optical disk 20 and converts it into an electrical signal during reproduction. And output. The optical disc 20 is a recordable optical disc, for example, a BD-R.

  During recording, the recording / reproducing unit 3 generates a recording pulse train for driving the light source of the optical pickup 2 based on the recording data and the recording strategy, and supplies this to a light source driving circuit (not shown) of the optical pickup 2. To do. During reproduction, the recording / reproducing unit 3 emits reproduction laser light from the optical pickup 2.

  The FEP 4 generates a reproduction signal (reproduction RF signal) obtained by reading information recorded on the optical disc 20, a focus error signal, a tracking error signal, and the like based on the electric signal supplied from the optical pickup 2.

  The recording state detection unit 5 obtains data necessary for calculating a modulation level of a reproduction signal obtained by reproducing data recorded by trial writing on the optical disc 20 and a β value indicating the degree of asymmetry of the reproduction signal. To detect.

  FIG. 2 is a block diagram illustrating a configuration of the recording state detection unit 5. As shown in FIG. 2, the recording state detection unit 5 includes an HPF (High Pass Filter) 51, a peak level detection unit 52, a bottom level detection unit 53, and a peak level detection unit 54.

  The high pass filter 51 cuts the direct current component of the reproduction signal input from the optical pickup 2. An example of the reproduction signal from which the direct current component is cut is shown in FIG. This signal is input to the peak level detector 52 and the bottom level detector 53.

  The peak level detection unit 52 detects, by analog processing, a peak on the + side of the reproduction signal whose DC component has been cut by the high-pass filter 51. The output of the peak level detector 52 is A1.

  The bottom level detection unit 53 detects the negative peak of the reproduction signal from which the direct current component has been cut by the high-pass filter 51 by analog processing. The output of the bottom level detector 53 is A2.

  The peak level detector 54 detects the + side peak of the reproduction signal input from the optical pickup 2 by analog processing. The output of the peak level detector 54 is A3. The data A1 to A3 detected by the recording state detection unit 5 is sent to the reproduction signal processing unit 6.

  The reproduction signal processing unit 6 calculates the modulation degree and β value of the reproduction signal from A1 to A3 detected by the recording state detection unit 5. The modulation degree m is obtained by the following (Equation 1), and the β value is obtained by the following (Equation 2).

m = (A1-A2) / A3 (Formula 1)
β = (A1 + A2) / (A1-A2) (Formula 2)
In addition, the reproduction signal processing unit 6 uses an optical disk based on a phase difference between a signal obtained by binarizing the reproduction signal and a PLL clock generated from the reproduction signal by a PLL (Phase Locked Loop) circuit (not shown). Then, the edge shift amount of the recording mark recorded in the recording medium 20 and the jitter of the reproduction signal are measured.

  The system controller 7 has a CPU (Central Processing Unit) and controls the operation of the entire optical disc recording / reproducing apparatus 1 by performing processing according to a control program.

  The program memory 8 stores a control program for the system controller 7. The data memory 9 temporarily stores data to be recorded on the optical disc 20, data reproduced from the optical disc 20, and the like.

  The internal bus 10 is a path for transmitting information of the entire optical disc recording / reproducing apparatus 1. The IF unit 11 performs an interface between the host device 30 and the internal bus 10.

  The host device 30 is, for example, a personal computer, and instructs the optical disc recording / reproducing device 1 to record or reproduce the optical disc 20. The host device 30 and the optical disc recording / reproducing device 1 may be housed in the same housing. Such a form is adopted, for example, in a BD recorder.

  Recording on the optical disk 20 is performed by using laser light emitted from the optical pickup 2 as a light emission waveform of a pulse train. An example of a recording pulse train of laser light configured according to the recording strategy is shown in FIG. A recording pulse train of laser light as shown in FIG. 4C is based on a clock as shown in FIG. 4A, for example, a data pattern (2T mark, 3T space, 3T mark, 2T space, 5T mark). T is a clock cycle.

  In FIG. 4C, Pw is a level as recording peak power, Pm is a level as intermediate power, Ps is a level as space power, and Pc is a level as cooling power.

  The recording strategy has parameters for configuring a recording pulse train corresponding to the length of the recording mark (mark length) as shown in FIG. This parameter includes Tstp indicating the recording start timing time (start timing time of the first pulse) of each recording mark, Tscp indicating the start timing time of the cooling pulse, Tecp indicating the end timing time of the cooling pulse, and the intermediate power pulse. A parameter indicating the start timing time is included. Such parameters are set according to each mark length (2T, 3T,...) And a space length at both ends of each recording mark (time length between recording marks).

  During the high level period of the data pattern, the recording layer of the optical disk 20 is subjected to a rapid cooling condition of heating → cooling by outputting laser light in combination with the recording power of the levels Pw and Pm and the cooling power of the level Pc. Recording marks as shown in 4 (d) are formed. In FIG. 4, 2M, 3M, and 5M indicate recording marks with mark lengths of 2T, 3T, and 5T, respectively, and 2S and 3S indicate spaces with space lengths of 2T and 3T, respectively.

  Here, a combination of the mark length and the space length of the recording mark capable of measuring the edge shift amount in the optical disc recording / reproducing apparatus 1 will be described with reference to FIG. 5A is an example of a recording pulse train corresponding to the recording strategy, FIG. 5B is a recording mark recorded on the optical disc 20, and FIG. 5C is a mark length that can measure the edge shift amount. It is a table | surface which shows the combination of and space length. The edge shift amount is an amount by which the edge of the recording mark deviates from the reference position of the clock.

  In the optical disc, the mark length and the space length used for recording are determined. For example, in the BD-R, the mark length and the space length are 2T to 9T. FIG. 5 shows a combination in this case.

  In FIG. 5A, the horizontal axis is a time axis indicating pulse timing, and the vertical axis indicates a recording power level. In FIG. 5B, the left side in the figure is the front and the right side in the figure is the rear. In FIG. 5C, “≧ 5M” indicates a recording mark having a mark length of 5T or more (5T to 9T), and “≧ 5S” indicates a space having a space length of 5T or more (5T to 9T).

  In the optical disc recording / reproducing apparatus 1, the reproduction signal processing unit 6 uses the spaces 2S, 3S, and 2S for the front edge (starting edge) and the rear edge (termination) of the recording marks 2M, 3M, 4M, and 5M or more. The amount of edge shift between 4S and 5S or more is measured.

  For example, at the front edge of the recording mark 2M, the edge shift amount can be measured for each of the four types of space of 2S, 3S, 4S, 5S or more in front of the recording mark 2M. Even at the 2M rear edge, the edge shift amount can be measured for each of the four types of space of 2S, 3S, 4S, 5S or more behind the recording mark 2M.

In the table shown in FIG. 5C, 2S2M is a combination of the space 2S in front of the recording mark 2M and the front edge of the recording mark 2M, and 3S2M is the space 3S in front of the recording mark 2M and the front side of the recording mark 2M. 4S2M is a combination of a space 4S in front of the recording mark 2M and a front edge of the recording mark 2M, and 5S2M is a space 5S or more in front of the recording mark 2M and a front edge of the recording mark 2M. 2M2S is a combination of a rear edge of the recording mark 2M and a space 2S behind the recording mark 2M, and 2M3S is a rear edge of the recording mark 2M and a space 3S behind the recording mark 2M. 2M4S is a combination of a rear edge of the recording mark 2M and a space 4S behind the recording mark 2M. M5S are respectively combined with the side of the trailing edge of the recording mark 2M recording mark 2M behind the space 5S above. The same applies to the recording marks 3M, 4M, 5M or more. That is, in the reproduction signal processing unit 6 of the optical disc recording / reproducing apparatus 1, when information is recorded on the BD type optical disc, the recording mark edge shift is performed for a total of 32 combinations in the table of FIG. Measure quantity.
Next, the operation when the recording strategy is corrected in the optical disc recording / reproducing apparatus 1 will be described with reference to the flowchart shown in FIG.

  The optical disc recording / reproducing apparatus 1 corrects the recording strategy when the optical disc 20 which is an unknown disc is loaded or when instructed by the host device 30. Here, it is assumed that the optical disc 20 is a BD-R, and the O method is used in the OPC process to determine the recording power whose β value matches the preset target β value as the optimum recording power.

  First, in step S10, the system controller 7 reproduces the optical disc 20 by the recording / reproducing unit 3 and the optical pickup 2, and the recording strategy and the target β value included in the disc information of the optical disc 20 are obtained from the reproduction signal obtained by FEP4. read. The read recording strategy and target β value are stored in the data memory 9.

  Next, in step S20, the system controller 7 executes an OPC process to calculate the optimum recording power Po and the modulation degree m.

  In the OPC process, the system controller 7 causes the recording / reproducing unit 3 to generate a test recording pulse train based on the test recording data and the recording strategy read in step S10. A laser beam is emitted, and trial writing is performed in the trial writing area of the optical disc 20. The test recording data used in the OPC process is random pattern data including all 32 combinations shown in FIG. 5C.

  The trial writing in the OPC process is performed at each power by changing the recording peak power Pw stepwise as shown in FIG. As shown in FIG. 7, the range in which the recording peak power Pw is varied is called an OPC range. The OPC range is, for example, a range of + 25% or −25% with respect to the center power as a reference of the range in which the recording peak power Pw is shaken. In FIG. 7, an example in which the recording peak power Pw is shaken in 16 steps within the range. Is shown.

  After the trial writing, the system controller 7 reproduces the trial-written area by the recording / reproducing unit 3 and the optical pickup 2, and causes the recording state detecting unit 5 to detect the data A1 to A3 from the reproduction signal obtained by the FEP4. .

  The system controller 7 uses the data A1 to A3 detected by the recording state detection unit 5 to calculate the modulation degree m by the above-described (Equation 1) for the recording peak power Pw at each stage (Equation The reproduction signal processing unit 6 is controlled so as to calculate the β value according to 2).

  The β characteristic with respect to the recording peak power Pw becomes a linear characteristic in the vicinity of the optimum recording power Po as shown in FIG. The system controller 7 determines the recording peak power Pw corresponding to the target β value read in step S10 as the optimum recording power Po. The calculated modulation degree m, β value, and optimum recording power Po are stored in the data memory 9.

  Next, in step S30, the system controller 7 determines whether or not the modulation degree m of the reproduction signal corresponding to the optimum recording power Po determined in step S20 is greater than or equal to a predetermined modulation degree threshold (for example, 35%). If it is equal to or greater than the modulation degree threshold (step S30: YES), the process proceeds to step S50, and if it is less than the modulation degree threshold (step S30: NO), the process proceeds to step S40.

  In step S40, the system controller 7 corrects the recording strategy so as to change the duty ratio of the recording pulse train corresponding to the recording strategy used in the OPC process in step S20. FIG. 9 shows a method for correcting the duty ratio of the recording strategy. The system controller 7 changes the duty ratio of the recording pulse train corresponding to all the recording marks by changing the recording strategy so that the recording start timing Tstp of all the recording marks is uniformly shifted in the direction of delaying by the same amount ΔTstp. To do. By such correction for changing the duty ratio, the modulation degree m of the reproduction signal can be increased.

  Then, it returns to step S20. Through steps S20 to S40, the system controller 7 determines the modulation degree of the reproduction signal corresponding to the optimum recording power Po when the modulation degree m of the reproduction signal corresponding to the optimum recording power Po calculated by the OPC process is smaller than the modulation degree threshold. After correcting the recording strategy so as to change the duty ratio of the recording pulse train until m becomes equal to or greater than the modulation degree threshold, the process of calculating the optimum recording power Po according to the corrected recording strategy with the changed duty ratio is repeated.

  In step S50, the system controller 7 causes the recording / reproducing unit 3 to generate a recording pulse train for testing with the optimum recording power Po based on the test recording data and the recording strategy, and based on this, the laser beam is emitted from the optical pickup 2 to the laser. Light is emitted, and trial writing is performed in the trial writing area of the optical disc 20. The recording strategy used here is the recording strategy used for calculating the optimum recording power Po at which the modulation degree m of the reproduction signal is equal to or greater than the modulation degree threshold value. This correction is performed when the duty ratio is changed in step S40. This is a later recording strategy.

  Next, in step S60, the system controller 7 causes the recording / playback unit 3 and the optical pickup 2 to play back the area that was trial-written in step S50, and from the playback signal obtained in FEP4, each recording mark recorded on the optical disc 20 is recorded. The reproduction signal processing unit 6 is caused to measure the edge shift amount and the reproduction signal jitter.

  Next, in step S70, the system controller 7 determines whether or not the jitter calculated in step S60 is a predetermined jitter threshold value (for example, 12%) or less. When it is below the jitter threshold (step S70: YES), the process proceeds to step S90, and when larger than the jitter threshold (step S70: NO), the process proceeds to step S80.

  In step S80, the system controller 7 corrects the recording strategy so as to change the timing of the edge (starting end, end) of the recording pulse train corresponding to the recording strategy used in the trial writing in step S50. The edge timing of the recording pulse train is changed by changing Tstp, Tscp, and Tecp corresponding to each recording mark so as to reduce the edge shift amount calculated in step S60.

  Thereafter, the process returns to step S50. Through steps S50 to S80, the system controller 7 determines the timing of the edge of the recording pulse train until the jitter of the reproduction signal becomes equal to or less than the jitter threshold when the jitter of the reproduction signal in the region trial-written in step S50 is larger than the jitter threshold. After correcting the recording strategy to be changed, the process of performing test writing is repeated according to the corrected recording strategy.

  In step S90, the system controller 7 uses the recording strategy used for the trial writing in step S50, in which the jitter of the reproduced signal in the trial-written area is equal to or less than the jitter threshold, for the optical disc recording / reproducing apparatus 1 for the optical disc 20. Determine as the recording strategy. Then, the system controller 7 controls the recording / reproducing unit 3 and the optical pickup 2 to write the determined recording strategy to the optical disc 20 in association with the serial number of the optical disc recording / reproducing apparatus 1.

  When the optical disc 20 on which the recording strategy determined by the above procedure is recorded is used in the optical disc recording / reproducing apparatus 1, the recording strategy recorded on the optical disc 20 is used.

  In the HTL (High to Low) type BD-R, the β value characteristic and the modulation degree characteristic with respect to the recording peak power obtained by the OPC process are shown in FIGS. Further, in the LTH (Low to High) type BD-R, the β value characteristic and the modulation degree characteristic with respect to the recording peak power obtained by the OPC process are shown in FIGS.

  FIG. 10 and FIG. 12 show the characteristics when correction for changing the duty ratio is not performed on the recording strategy included in the BD-R disc information as in the prior art. 11 and 13 show characteristics when correction for changing the duty ratio is performed as in the present embodiment. In the HTL type and the LTH type, the β value characteristics with respect to the recording peak power have opposite polarities. 10 to 13, the horizontal axis represents the ratio of the recording peak power used in the OPC process to the optimum recording power included in the BD-R disc information.

  When the correction for changing the duty ratio is not performed as in the prior art, the reproduction signal at the optimum recording power Po ′ at the target β value (for example, 8%) obtained by the OPC process as shown in FIGS. The degree of modulation may be below 30%. In this state, the amplitude of the reproduction signal is too small, and the jitter characteristics cannot be improved only by improving the edge shift, and the recording quality cannot be ensured.

On the other hand, when the correction for changing the duty ratio is performed as in the present embodiment, the reproduction signal is modulated at the optimum recording power Po at which the target β value (for example, 8%) is obtained, as shown in FIGS. The degree can be improved to 40% or more. Thereby, the jitter characteristic of the reproduction signal can be improved.

  FIG. 14 is a diagram showing an example of measurement results of the total 32 edge shift amounts shown in FIG. 5C when the recording strategy is not corrected in the HTL type BD-R. FIG. 14A shows the start edge of the recording mark, and FIG. 14B shows the edge shift amount at the end of the recording mark. On the other hand, FIGS. 15A and 15B show examples of measurement results of edge shift amounts at the start and end of the recording mark when the recording strategy is corrected so as to change the duty ratio of the recording pulse train. FIG. The correction amount ΔTstp of the recording mark recording start timing is 4 (T / 32).

  FIGS. 16A and 16B show a case in which the recording strategy is corrected so as to change the timing of the edge of the recording pulse train in order to improve the edge shift after the correction of the recording strategy for changing the duty ratio. It is a figure which shows an example of the measurement result of the edge shift amount in the start end of a recording mark, and an end.

  As shown in FIG. 15, when the recording strategy is corrected such that the duty ratio of the recording pulse train is changed in order to improve the modulation degree of the reproduction signal, the edge shift amount changes with respect to FIG. In particular, the recording mark 2M changes greatly.

  As described above, since the edge shift amount changes when the duty ratio is changed, a good edge shift amount as shown in FIG. 16 can be obtained by performing correction for improving the edge shift after the duty ratio is changed. Can do.

  FIG. 17 shows reproduction when recording is performed without correcting the recording strategy included in the disc information of the BD-R and when recording is performed using the recording strategy corrected by the procedure shown in FIG. It is a figure which shows an example of the jitter characteristic of a signal. As shown in FIG. 17, the jitter characteristic of the reproduction signal can be improved by correcting the recording strategy in the present embodiment.

  Here, how to determine the correction amount ΔTstp of the recording start timing of the recording mark will be described.

  In the case of the HTL type, it can be seen from FIGS. 10 and 11 that the β value and the modulation factor as shown in FIG. 18 are obtained when the recording strategy is corrected to change the duty ratio and when the correction is not performed. Correlation characteristics are obtained. According to FIG. 18, when the modulation degree changes by 10%, the β value changes by about 10%. Similarly, for the LTH type, a correlation characteristic between the β value and the modulation degree as shown in FIG. 19 is obtained from FIGS. According to FIG. 19, when the modulation degree changes by 10%, the β value changes by about 8%.

  In the case of the HTL type, the β value when the correction amount ΔTstp of the recording start timing of the recording mark is changed changes as shown in FIG. According to FIG. 20, if the correction amount ΔTstp is increased by 4 (T / 32), the β value increases by about 10%. In the case of the LTH type, the β value when the correction amount ΔTstp is changed changes as shown in FIG. According to FIG. 21, if the correction amount ΔTstp is increased by 4 (T / 32), the β value increases by about 10%.

  As described above, the relationship between the degree of modulation and the β value is obtained from FIGS. 18 and 19, and the relationship between the correction amount ΔTstp and the β value is obtained from FIGS. 20 and 21. Therefore, in the case of the HTL type, the relationship between the modulation factor and the correction amount ΔTstp is obtained from FIG. 18 and FIG. 20 through the β value. Similarly, in the case of the HTL type, the relationship between FIG. 19 and FIG. A relationship between the degree of modulation and the correction amount ΔTstp is obtained.

  As a result, a correction amount ΔTstp for changing the modulation degree by a desired amount is obtained. In the above example, in the case of the HTL type, in order to increase the modulation degree by 10%, the correction amount ΔTstp may be set to 4 (T / 32). In the case of the LTH type, the correction amount ΔTstp may be set to 3 (T / 32) in order to increase the modulation degree by 10%.

  As described above, in the present embodiment, the recording strategy is corrected so as to change the duty ratio of the recording pulse train to improve the modulation degree of the reproduction signal, and then the recording is performed so as to change the timing of the edge of the recording pulse train. By correcting the strategy to improve the edge shift of the recording mark, the recording strategy can be appropriately corrected to improve the jitter characteristic of the reproduction signal, and good recording quality can be obtained.

(Modification)
FIG. 22 is a flowchart showing the operation when the recording strategy is corrected in the optical disc recording / reproducing apparatus according to the modification of the embodiment of the present invention. The optical disc recording / reproducing apparatus according to this modification has the same configuration as the optical disc recording / reproducing apparatus 1 according to the above-described embodiment shown in FIG.

  In FIG. 22, the processing of steps S110 to S130 is the same as the processing of steps S10 to S30 in the flowchart of FIG. If it is determined in step S130 that the modulation degree m of the reproduction signal corresponding to the optimum recording power Po calculated in step S120 is greater than or equal to a predetermined modulation degree threshold (step S130: YES), the process proceeds to step S160, and is less than the modulation degree threshold. (Step S130: NO), the process proceeds to Step S140.

  In step S140, the system controller 7 changes the optimum recording power Po from the value calculated in step S120. As the optimum recording power Po after the change, a recording power having a modulation degree exceeding 40%, for example, is selected from the characteristics shown in FIGS.

  Next, in step S150, the system controller 7 corrects the recording strategy so as to change the duty ratio of the recording pulse train according to the recording strategy used in the OPC process in step S120. The method for correcting the duty ratio of the recording strategy is the same as in step S40 described above.

  Hereinafter, the processing of steps S160 to S200 is the same as the processing of steps S50 to S90 in the flowchart of FIG.

  According to this modification, as in the above embodiment, the recording strategy can be appropriately corrected to improve the jitter characteristic of the reproduction signal, and good recording quality can be obtained, and the OPC process is re-executed. Without changing the optimum recording power Po, the use of the trial writing area of the optical disc 20 can be saved. In addition, the processing time can be shortened.

  In the above-described embodiment and its modifications, the case where the optical disc 20 is a BD-R has been described. However, the optical disc 20 may be a rewritable optical disc such as a BD-RE. In this case, in the OPC process, a known κ method or γ method using a modulation degree is employed instead of the β method.

DESCRIPTION OF SYMBOLS 1 Optical disk recording / reproducing apparatus 2 Optical pick-up 3 Recording / reproducing part 4 FEP
5 Recording State Detection Unit 6 Reproduction Signal Processing Unit 7 System Controller 8 Program Memory 9 Data Memory 10 Internal Bus 11 IF Unit 20 Optical Disk 30 Host Device

Claims (4)

According to the recording strategy registered in the optical disc, trial writing is performed on the optical disc with a plurality of recording powers, and an optimum recording power that is optimum recording power for the main recording of the optical disc is calculated from a reproduction signal obtained by reproducing the trial written data. An optimum recording power calculating means;
A modulation factor calculating means for calculating a modulation factor of a reproduction signal obtained by reproducing data trial-written on the optical disc;
Duty ratio correction means for correcting the recording strategy so as to change the duty ratio of the recording pulse train according to the recording strategy;
When the modulation degree of the reproduction signal corresponding to the optimum recording power calculated by the optimum recording power calculation means is smaller than a predetermined modulation degree threshold, the modulation degree of the reproduction signal corresponding to the optimum recording power becomes equal to or greater than the modulation degree threshold. Until the duty ratio correction means corrects the recording strategy so as to change the duty ratio of the recording pulse train, and the optimum recording power calculation means calculates the optimum recording power according to the corrected recording strategy after changing the duty ratio. Duty ratio correction control means for controlling to repeat the process of calculating
The optimum recording power calculated by the optimum recording power calculating means, and the recording power used by the optimum recording power calculating means for calculating the optimum recording power is the optimum recording power at which the modulation degree of the reproduction signal of the test-written data is equal to or greater than the modulation degree threshold. Trial writing means for performing trial writing on the optical disc in accordance with a strategy;
An edge shift amount measuring means for measuring an edge shift amount of each recording mark recorded on the optical disc from a reproduction signal of data trial-written by the test writing means;
Jitter measuring means for measuring jitter of a reproduction signal of data trial-written by the test writing means;
Pulse edge timing correction means for correcting the recording strategy so as to change the timing of the edge of the recording pulse train in order to reduce the edge shift amount;
When the jitter measured by the jitter measuring means is greater than a predetermined jitter threshold, the pulse edge timing correcting means reduces the edge of the recording pulse train until the jitter measured by the jitter measuring means falls below the jitter threshold. Pulse edge timing for controlling to repeat test writing by the test writing means in accordance with the corrected recording strategy in which the timing of the edge of the recording pulse train is changed after correcting the recording strategy so as to change the timing Correction control means;
A recording strategy in which the jitter of a reproduction signal of data trial-written by the trial writing means is equal to or less than the jitter threshold is determined as a recording strategy used by the optical disc recording / reproducing apparatus for the optical disc, and the recording strategy is stored in the optical disc. An optical disc recording / reproducing apparatus comprising: a recording strategy determining unit for writing. According to the recording strategy registered in the optical disc, trial writing is performed on the optical disc with a plurality of recording powers, and an optimum recording power that is optimum recording power for the main recording of the optical disc is calculated from a reproduction signal obtained by reproducing the trial written data. An optimum recording power calculating means;
A modulation factor calculating means for calculating a modulation factor of a reproduction signal obtained by reproducing data trial-written on the optical disc;
Optimum recording power changing means for changing the optimum recording power when the modulation degree of the reproduction signal corresponding to the optimum recording power calculated by the optimum recording power calculating means is smaller than a predetermined modulation degree threshold;
When the modulation degree of the reproduction signal corresponding to the optimum recording power calculated by the optimum recording power calculation means is smaller than a predetermined modulation degree threshold, the recording strategy is changed so as to change the duty ratio of the recording pulse train corresponding to the recording strategy. Duty ratio correction means for correcting
Test writing means for performing test writing on the optical disc in accordance with the recording strategy after correction by the duty ratio correction means at the optimum recording power changed by the optimum recording power changing means;
An edge shift amount measuring means for measuring an edge shift amount of each recording mark recorded on the optical disc from a reproduction signal of data trial-written by the test writing means;
Jitter measuring means for measuring jitter of a reproduction signal of data trial-written by the test writing means;
Pulse edge timing correction means for correcting the recording strategy so as to change the timing of the edge of the recording pulse train in order to reduce the edge shift amount;
When the jitter measured by the jitter measuring means is greater than a predetermined jitter threshold, the pulse edge timing correcting means reduces the edge of the recording pulse train until the jitter measured by the jitter measuring means falls below the jitter threshold. Pulse edge timing for controlling to repeat test writing by the test writing means in accordance with the corrected recording strategy in which the timing of the edge of the recording pulse train is changed after correcting the recording strategy so as to change the timing Correction control means;
A recording strategy in which the jitter of a reproduction signal of data trial-written by the trial writing means is equal to or less than the jitter threshold is determined as a recording strategy used by the optical disc recording / reproducing apparatus for the optical disc, and the recording strategy is stored in the optical disc. An optical disc recording / reproducing apparatus comprising: a recording strategy determining unit for writing. According to the recording strategy registered in the optical disc, trial writing is performed on the optical disc with a plurality of recording powers, and an optimum recording power that is optimum recording power for the main recording of the optical disc is calculated from a reproduction signal obtained by reproducing the trial written data. Optimal recording power calculation step,
When the modulation degree of the reproduction signal corresponding to the optimum recording power calculated in the optimum recording power calculation step is smaller than a predetermined modulation degree threshold, the modulation degree of the reproduction signal corresponding to the optimum recording power is equal to or greater than the modulation degree threshold. Until the recording strategy is corrected so as to change the duty ratio of the recording pulse train according to the recording strategy, the process of calculating the optimum recording power using the corrected recording strategy after changing the duty ratio is repeated. A duty ratio correction step;
The recording strategy used in the calculation of the optimum recording power at the optimum recording power calculated in the optimum recording power calculating step or the duty ratio correcting step and having a modulation degree of the reproduction signal of the test written data equal to or greater than the modulation degree threshold. A test writing step for performing test writing on the optical disc according to
A measurement step of measuring the edge shift amount of each recording mark recorded on the optical disc and the jitter of the reproduction signal from the reproduction signal of the data trial-written by the trial writing step;
When the jitter measured in the measurement step is larger than a predetermined jitter threshold, the edge of the recording pulse train is reduced so as to reduce the edge shift amount until the jitter of the reproduction signal of the trial written data becomes equal to or lower than the jitter threshold. After correcting the recording strategy so as to change the timing, a pulse edge timing correction step of repeating the test writing according to the corrected recording strategy in which the edge timing of the recording pulse train is changed, and
The recording strategy used for the trial writing in the trial test writing step or the pulse edge timing correction step so that the jitter of the reproduction signal is not more than the jitter threshold is determined as the recording strategy used by the optical disc recording / reproducing apparatus for the optical disc. And a determination step of writing to the optical disc. According to the recording strategy registered in the optical disc, trial writing is performed on the optical disc with a plurality of recording powers, and an optimum recording power that is optimum recording power for the main recording of the optical disc is calculated from a reproduction signal obtained by reproducing the trial written data. Optimal recording power calculation step,
An optimum recording power changing step for changing the optimum recording power when the modulation degree of the reproduction signal corresponding to the optimum recording power calculated in the optimum recording power calculating step is smaller than a predetermined modulation degree threshold;
When the modulation degree of the reproduction signal corresponding to the optimum recording power calculated in the optimum recording power calculation step is smaller than a predetermined modulation degree threshold, the recording strategy is changed so as to change the duty ratio of the recording pulse train according to the recording strategy. A duty ratio correction step for correcting
A test writing step for performing test writing on the optical disc in accordance with the recording strategy after the correction by the duty ratio correction step at the optimum recording power after the change in the optimum recording power changing step;
A measurement step of measuring the edge shift amount of each recording mark recorded on the optical disc and the jitter of the reproduction signal from the reproduction signal of the data trial-written by the trial writing step;
When the jitter measured in the measurement step is larger than a predetermined jitter threshold, the edge of the recording pulse train is reduced so as to reduce the edge shift amount until the jitter of the reproduction signal of the trial written data becomes equal to or lower than the jitter threshold. After correcting the recording strategy so as to change the timing, a pulse edge timing correction step of repeating the test writing according to the corrected recording strategy in which the edge timing of the recording pulse train is changed, and
The recording strategy used for the trial writing in the trial test writing step or the pulse edge timing correction step so that the jitter of the reproduction signal is not more than the jitter threshold is determined as the recording strategy used by the optical disc recording / reproducing apparatus for the optical disc. And a determination step of writing to the optical disc.

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