JP4555371B2 - Optical information recording method - Google Patents

Description

The present invention is, for example, such as an optical disk, optically relates to an information recording how to perform a test recording before recording information signals to optimize recording conditions for the optical information recording medium for recording and reproducing information.

  In recent years, optical discs, optical cards, optical tapes, and the like have been proposed and developed as optical recording media. Among them, the optical disk is attracting attention as a medium capable of recording and reproducing information with a large capacity and high density.

  One type of rewritable optical disk is a phase change optical disk. The recording film used for the phase change type optical disk is in an amorphous state or a crystalline state depending on a heating condition and a cooling condition by a laser beam. Note that the amorphous state and the crystalline state are reversible. The optical constant (refractive index and extinction coefficient) of the recording film differs between the amorphous state and the crystalline state. In a phase change type optical disc, two states are selectively formed on a recording film in accordance with an information signal, and the resulting optical change (change in transmittance or reflectance) is used to record information signals. Perform playback.

  In order to obtain the above two states, an information signal is recorded by the following method. When the recording film of the optical disc is irradiated with laser light (power level Pp) focused by the optical head in a pulsed manner (this is called a recording pulse) and the temperature of the recording film is raised beyond the melting point, As the laser beam passes, it is rapidly cooled to become an amorphous recording mark. Further, when a laser beam (power level Pb, where Pb <Pp) is high enough to raise the temperature of the recording film to a temperature not lower than the crystallization temperature but not higher than the melting point, the recording film in the irradiated portion is in a crystalline state. become. This power level Pb is called erasing power.

  In this way, a recording pattern of a recording mark made of an amorphous region corresponding to a recording data signal and a non-mark portion made of a crystal region (this is called a space) is formed on the track of the optical disk. An information signal can be reproduced by utilizing the difference in optical characteristics between the crystalline region and the amorphous region.

  In recent years, a mark edge recording (also referred to as PWM recording) method has been frequently used instead of a mark position recording (also referred to as PPM recording) method. In mark position recording, information is provided only at the position of the recording mark itself, whereas in mark edge recording, information is provided at both the front edge and the rear edge of the recording mark. There is a merit of improvement.

  Further, a Z-CLV (Zoned Constant Line-ar Velocity) format has been proposed as a method for facilitating the rotation control of the spindle motor of the recording / reproducing apparatus while increasing the recording capacity of the optical disk. An optical disk in the Z-CLV format is a disk in which the recording area is divided into zones composed of a predetermined number of tracks, and the number of sectors per round is increased from the inner zone to the outer zone. It is.

  An apparatus for recording and reproducing such a Z-CLV disc gradually decreases the rotational speed of the disc from the inner periphery to the outer periphery of the disc (here, the rotational speed in each zone is constant), Recording and reproduction are performed so that the linear velocity is substantially constant over the entire circumference of the disk.

  The Z-CLV format is described, for example, as “M-CLV (Modified Constant Linear Velocity) format” on page 223 of “Optical Disc Technology” (1988), Radio Technology Co., Ltd.

  By the way, since the optical disk is an exchangeable recording medium, the optical disk recording / reproducing apparatus is required to be able to stably record and reproduce a plurality of different optical disks. However, even in an optical disc manufactured under the same conditions, the power level of laser light optimal for recording and reproduction may differ from each other due to variations in manufacturing and changes with time. In addition, the power of the laser light reaching the recording film of the optical disk may vary due to contamination on the substrate surface of the optical disk, a decrease in transmission efficiency of the optical system of the recording / reproducing apparatus, or a change in operating state.

  In addition, especially in the case of the mark edge recording method, variations in the thermal characteristics of the optical disk affect the formation state of the recording marks themselves and the degree of thermal interference between the recording marks. Therefore, there is a possibility that the optimum edge position of the recording pulse is different for each optical disc.

  An example of a method for stably recording / reproducing an information signal without being affected by the fluctuation of the optimum power level of the laser beam and the fluctuation of the optimum edge position of the recording pulse is disclosed in Japanese Patent Laid-Open No. 4-137224. Has been. This is because, prior to recording an information signal, after performing test recording with a specific data pattern (referred to as a test signal), the recorded test signal is reproduced, the reproduced signal is measured, and a recording mark is recorded. The edge position of the recording pulse is controlled so as to be optimum by obtaining the edge position.

  As another example, Japanese Patent Application Laid-Open No. 6-195713 discloses a technique for controlling at least one of a recording pulse edge position and a recording power after obtaining an edge position of a recording mark. Japanese Laid-Open Patent Publication No. 9-63056 discloses a method for determining the optimum recording power from the power dependency of the bit error rate. Further, Japanese Patent Laid-Open No. 7-129959 discloses a method for controlling the edge position of a recording pulse according to the length of a recording mark and the length of a space before and after the recording mark.

On the other hand, a method for improving the number of rewritable times of an optical disk is proposed in Japanese Patent Laid-Open No. 9-219022. This is to reverse the polarity (1 or 0) of the recording data signal at random, thereby avoiding that the damage to the recording film is concentrated at a specific position and suppressing the deterioration of the recording film.
JP-A-4-137224 JP-A-6-195713 Japanese Patent Laid-Open No. 9-63056 JP-A-7-129959 Japanese Patent Laid-Open No. 9-219022

  However, the above-described conventional method has a problem in that an error may occur in the determination of the edge position of the recording pulse because the measurement value of the edge position of the recording mark is biased. Hereinafter, this problem will be described with reference to FIGS.

  FIGS. 11 to 14 show examples of mark distortion caused by the positional relationship between a previously recorded recording mark and an overwritten recording mark. 11 to 14, the state of the track of the optical disc before the recording mark is overwritten in the upper stage, the pattern of the test signal (as a recording data signal) to be overwritten in the middle stage, and the recording mark is overwritten in the lower stage. Each of the track states after writing is shown.

  Usually, a predetermined track is often assigned as a track for recording a recording mark for test recording. In this case, the recording mark is repeatedly overwritten on the predetermined track. Therefore, when some test signal (or information signal) is already recorded on the track to be test-recorded, the shape of the recording mark recorded by overwriting is distorted due to the influence of the recording mark already recorded. .

  In the case of a phase change optical disc, the optical absorption characteristics are different between an amorphous region (that is, a region where a recording mark exists) and a crystalline region. Therefore, even when the laser beam with the same energy is irradiated, the temperature rising rate in the recording film of the optical disc differs between the amorphous region and the crystal region. Thereby, in the case of a disk configuration in which the optical absorption in the amorphous region is larger than that in the crystal region, the overwritten recording mark tends to be large on the amorphous region. As a result, the edge position of the recording mark moves in the direction in which the recording mark extends, as shown by hatching in FIGS. This is called mark distortion. In the case of a disk configuration in which the optical absorption in the amorphous region is smaller than that in the crystal region, the above may be reversed.

  Accordingly, the shape of the recording mark changes depending on the overlap between the recording mark to be recorded in the test recording and the previous recording mark. As a result, the edge position of the recording mark varies. If the signal already recorded on the track and the test signal to be overwritten are the same or similar, the overlap between the previous recording mark and the overwritten recording mark will be sufficient unless the disc rotational fluctuation is large. It will always be the same. Therefore, the measurement value of the measured edge position is biased due to the phase relationship between the previous data pattern and the overwritten data pattern.

  For example, as shown in the upper part of FIG. 11, when the recording mark is overwritten using the test signal having the pattern shown in the middle part of the track 111 in which the recording mark 113 already exists, the lower part of the figure shows. As described above, when the overwritten recording mark 112 overlaps the previous recording mark 113, the mark distortion 114 occurs.

  Here, when the front end interval x of the recording mark 112 and the recording mark 115 is measured to determine the front end edge position of the recording pulse of 3T (T is the clock cycle of the recording data signal), as shown in FIG. When the mark distortion 114 occurs only at the rear end portion of the written recording mark 112, the mark distortion 114 does not affect the front end interval x. However, as shown in FIG. 12, when the front end of the recording mark 115 of the overwriting 3T recording pulse overlaps the previous recording mark 113, a mark distortion 116 occurs at the front end of the recording mark 115, and the measured front end interval Becomes x−Δ1.

  Further, as shown in FIG. 13, when the front end of the recording mark 112 of the 10T recording pulse overlaps the previous recording mark 113, a mark distortion 114 occurs at the front end of the recording mark 112, and the measured front end interval is x + Δ2. Become.

  Further, as shown in FIG. 14, the measurement is performed when both the front end of the recording mark 115 of the 3T recording pulse and the front end of the recording mark 112 of the 10T recording pulse overlap the previous recording marks 113 and 116. The front end interval is x−Δ1 + Δ2.

  Further, the conventional method has a problem that the recording power is not necessarily optimum after the recording pulse is controlled to the optimum edge position. Hereinafter, this problem will be described with reference to FIG.

  FIG. 15 shows a case where a periodic signal of a shortest mark (for example, a recording mark by a 3T recording pulse in the case of 8-16 modulation, hereinafter referred to as a 3T mark) is recorded while changing a recording pulse width. The relationship between the recording peak power Pp and the bit error rate (or may be jitter) is shown.

  When the edge position of the recording pulse is adjusted by test recording, the length of the recording pulse (or recording pulse train) changes. Therefore, the energy that the recording pulse gives to form the recording mark is affected by the adjustment of the edge position. This effect is particularly noticeable when a short mark such as the shortest mark is formed. As a result, the optimum recording power also changes.

  For example, when the length of the recording pulse for forming the 3T mark, which is the shortest mark in 8-16 modulation, is reduced by adjusting the edge position, the energy for forming the 3T mark is reduced, so that the bit error rate is reduced. The peak power dependency changes from g1 to g2 shown in FIG. As a result, the optimum recording power (this is often determined by multiplying the power Pth1 or Pth2 when the bit error rate reaches the predetermined threshold Bth by a constant value) is higher than before the edge position adjustment. Will be.

  Contrary to the above problem, the conventional method sometimes has a problem that the edge position of the recording pulse is not always optimal after adjusting the recording power. This will be described below.

  When the recording power is adjusted by test recording, the energy given to the recording film of the optical disk by the laser light changes. Therefore, even if the length of the recording pulse or the recording pulse train is the same, when the recording power changes, the length of the recording mark formed on the track on the optical disk, that is, the edge position also changes. This effect is particularly noticeable when a short mark is formed. As a result, the optimum edge position of the recording pulse for optimizing the edge position of the recording mark changes. For example, when the recording power is increased by test recording, the front edge of the edge position of the 3T mark extends forward, and the rear edge of the edge position extends backward, so the edge position of the recording pulse for recording the 3T mark is not optimal. It will disappear.

  Further, in the Z-CLV format, the optical disk is rotated at a constant rotational speed in each zone, so that the linear velocity and the linear density differ depending on the radius in each zone. That is, the linear velocity and the recording linear density decrease as it goes to the outer periphery in each zone. Therefore, in the conventional method, when performing test recording on an optical disc in the Z-CLV format, the optimum recording power or the optimum edge position of the recording pulse is not necessarily obtained over the entire area in each zone. there were.

  Further, for example, in the method disclosed in Japanese Patent Laid-Open No. 9-219022, the polarity of the data pattern is randomly reversed when the edge position of the recording pulse is determined by test recording. Depending on the polarity, the relationship between the recording mark and the space (that is, the relationship between the front end edge and the rear end edge of the recording mark) may be reversed. In this case, there is a problem that the front edge and the rear edge of the recording mark cannot be distinguished.

The present invention, these in order to solve the conventional problems, recording power and by appropriately determining the test recording the recording conditions such as the edge positions of recording pulses, the recording capable optical histological information precise information signal an object of the present invention is to provide a recording how.

In order to achieve the above object, a first optical information recording method of the present invention uses a rewritable optical information recording medium, and performs test recording before recording an information signal on the optical information recording medium. In the optical information recording method to be performed, the step (a) of setting the recording power of the light source to an initial value and recording the first test signal on the optical information recording medium, and the step (a) from the optical information recording medium Step (b) for determining an appropriate value of the edge position of the recording pulse based on the result of reproducing the first test signal recorded in step (b), and determining the appropriate edge position of the recording pulse in step (b). (C) recording the second test signal on the optical information recording medium, and reproducing the second test signal recorded in the step (c) from the optical information recording medium. Shi Based on the result seen including a step (d) to determine the proper value of the recording power, in the step (a), a plurality of sectors of the optical information recording medium, the starting point of the test recording, random for each sector And in step (b), based on the average of the results of reproducing the first test signal from the plurality of sectors, an appropriate value of the edge position of the pulse of the recording data signal is obtained. It is characterized by determining .

  In this method, after determining the appropriate value of the edge position of the recording pulse, test recording is further performed with the recording pulse set to the appropriate value to optimize the recording power. As a result, both the edge position of the recording pulse and the recording power can be optimized, so that the information signal can be accurately recorded on the optical information recording medium.

Also , it is possible to average the deviation of the edge interval of the test signal caused by overwriting the recording mark of the test signal on the recording mark already recorded in the area where the test recording is to be performed on the optical information recording medium. And the edge position of the recording data signal can be optimized more precisely.

  According to this method, since the correlation between the recording mark of the test signal that is overwritten in the area where the test recording is to be performed and the recording mark that has already been recorded further decreases, the deviation in the edge interval of the test signal is reduced. Averaging can be performed, and the edge position of the recording data signal can be optimized more precisely.

In the first optical information recording method, prior to the step (a), a recording pulse edge position is set to a predetermined value and a second test signal is recorded on the optical information recording medium. (E-1) and a step (e-2) of determining an appropriate value of the recording power based on the result of reproducing the second test signal recorded in the step (e-1) from the optical information recording medium. And an appropriate value of the recording power determined in the step (e-2) is preferably used as the initial value of the recording power in the step (a).

  As a result, both the edge position of the recording pulse and the recording power can be optimized more precisely, and the information signal can be recorded accurately on the optical information recording medium.

In the first optical information recording method, the step (b) includes an edge interval of the first test signal and a reproduction signal obtained by reproducing the first test signal from the optical information recording medium. It is preferable that the method includes a step of comparing with the edge interval of.

Alternatively, in the first optical information recording method, any one of a bit error rate and jitter of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium in the step (b) Preferably, the edge position of the recording pulse that minimizes the measurement result is determined as an appropriate value.

Alternatively, in the first optical information recording method, in the step (d), any one of a bit error and jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium is calculated. It is preferable that an appropriate value of the recording power is determined based on a recording power value that includes a measurement step and the measurement result is a predetermined value or less.

Furthermore, in the first optical information recording method, the step (e-2) includes any one of a bit error and a jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium. It is preferable to determine an appropriate value of the recording power based on the value of the recording power such that the measurement result is equal to or less than a predetermined value.

In order to achieve the above object, a second optical information recording method of the present invention uses a rewritable optical information recording medium, and performs test recording before recording an information signal on the optical information recording medium. In the optical information recording method, the step (a) of setting the edge position of the recording pulse to the initial position and recording the first test signal on the optical information recording medium, and the step from the optical information recording medium are performed. (B) determining an appropriate value of the recording power of the light source based on the result of reproducing the first test signal recorded in (a), and based on the recording power determined in the step (b), A step (c) of recording a second test signal on the optical information recording medium, and a recording based on a result of reproducing the second test signal recorded in the step (c) from the optical information recording medium. (D) determining an appropriate value of the edge position of the pulse, and in step (c), the start point of the test recording is randomly shifted for each sector in the plurality of sectors of the optical information recording medium. In step (d), an appropriate value of the edge position of the pulse of the recording data signal is determined based on the average of the results of reproducing the second test signal from the plurality of sectors. It is characterized by that.

  In this method, after determining the appropriate value of the recording power, test recording is further performed with the recording power set to the appropriate value to optimize the edge position of the recording pulse. As a result, both the edge position of the recording pulse and the recording power can be optimized, so that the information signal can be accurately recorded on the optical information recording medium.

Also , it is possible to average the deviation of the edge interval of the test signal caused by overwriting the recording mark of the test signal on the recording mark already recorded in the area where the test recording is to be performed on the optical information recording medium. And the edge position of the recording data signal can be optimized more precisely.

  According to this method, since the correlation between the recording mark of the test signal that is overwritten in the area where the test recording is to be performed and the recording mark that has already been recorded further decreases, the deviation in the edge interval of the test signal is reduced. Averaging can be performed, and the edge position of the recording data signal can be optimized more precisely.

In the second optical information recording method, prior to step (a), a recording power is set to a predetermined value, and a first test signal is recorded on the optical information recording medium (e- 1) and determining an appropriate value of the edge position of the recording pulse based on the result of reproducing the first test signal recorded in step (e-1) from the optical information recording medium (e-2) And an appropriate value of the edge position of the recording pulse determined in the step (e-2) is preferably used as the initial position of the edge position of the recording pulse in the step (a).

  As a result, both the edge position of the recording pulse and the recording power can be optimized more precisely, and the information signal can be recorded accurately on the optical information recording medium.

  Furthermore, in the step (e-1), it is preferable that the recording start point on the optical information recording medium is randomly shifted at at least one timing for each sector and each overwrite.

  Moreover, it is preferable to include a step of recording a data pattern uncorrelated with the test signal in an area where test recording is performed on the optical information recording medium before the step (e-1).

In the second optical information recording method, the step (b) is any one of a bit error rate and a jitter of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium. It is preferable to determine an appropriate value of the recording power based on the value of the recording power such that the measurement result becomes a predetermined value or less.

In the second optical information recording method, the step (d) includes an edge interval of the second test signal and a reproduction signal obtained by reproducing the second test signal from the optical information recording medium. It is preferable that the method includes a step of comparing with the edge interval of.

In the second optical information recording method, any one of a bit error rate and jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium in the step (d) Preferably, the edge position of the recording pulse that minimizes the measurement result is determined as an appropriate value.

  The step (e-2) compares the edge interval of the first test signal with the edge interval of the reproduction signal obtained by reproducing the first test signal from the optical information recording medium. Preferably a step is included.

  The step (e-2) includes a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium. Preferably, the edge position of the recording pulse that minimizes the result is determined as an appropriate value.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of a recording / reproducing apparatus (optical information recording apparatus) according to the first embodiment of the present invention.

  This recording / reproducing apparatus is an apparatus for recording / reproducing information using the optical disc 1, and includes a spindle motor 10 for rotating the optical disc 1 and a laser light source (not shown), and a laser beam at a desired location on the optical disc 1. And an optical head 9 for focusing the light. The operation of the entire recording / reproducing apparatus is controlled by the system control circuit 2 (recording condition determining means). As the optical disk 1, it is preferable to use a phase change disk whose recording film is made of a phase change material.

  This recording / reproducing apparatus determines a recording start point shift circuit 3 (recording start point shifting means) that randomly shifts a recording start point for each sector and records a recording pulse edge position in order to record information on the optical disc 1. An edge test signal generation circuit 4 (test signal generation means) for generating a test signal for performing the test.

  The recording / reproducing apparatus generates, as recording means, a modulation circuit 5 that generates a binarized recording data signal according to an information signal to be recorded, and a recording pulse for driving a laser according to the recording data signal. A recording signal generation circuit 6 and a recording pulse edge adjustment circuit 7 for adjusting the edge position of the recording pulse output from the recording signal generation circuit 6 are provided. Further, a laser driving circuit 8 is provided for modulating a current for driving the laser light source in the optical head 9 in accordance with the recording pulse output from the recording pulse edge adjusting circuit 7.

  The recording / reproducing apparatus detects a timing of the edge of the reproduction signal and a reproduction signal processing circuit 11 that performs waveform processing of the reproduction signal based on the reflected light from the optical disk 1 as reproduction means for reproducing information from the optical disk 1. An edge timing detection circuit 12 for performing reproduction, and a demodulation circuit 13 for obtaining reproduction information.

  Next, the operation of the recording / reproducing apparatus of the present embodiment will be described using the flowchart of FIG.

  At the time of test recording, first, the optical head 9 seeks to a predetermined track on the optical disk 1 (step 1, hereinafter abbreviated as S1), and the system control circuit 2 sets the set value of the recording power in the laser drive circuit 8. Determine (S2). The edge test signal generation circuit 4 generates a test signal and sends it as a recording data signal to the recording signal generation circuit 6 (S3).

  The recording signal generating circuit 6 detects how many times the channel inversion interval of the recording data signal corresponds to the channel clock period T. Then, a predetermined number and a predetermined width of recording pulses are generated at a predetermined timing according to the length of the recording mark.

  Here, the recording start point shift circuit 3 randomly shifts the start position of the recording gate signal for each sector and sends it to the recording signal generation circuit 6. The recording gate signal is a digital signal “1” or “0”, which is “1” only when information is recorded on the optical disc 1, and is “0” otherwise. On the other hand, the signal may be “0” when recording and “1” at other times.

  By thus shifting the start position of the recording gate signal at random, the recording start point of a series of recording data signals recorded in the sector of the optical disc 1 is randomly shifted for each sector (S4). Thereafter, the recording pulse edge adjusting circuit 7 inputs a recording pulse for driving the laser light source to the laser driving circuit 8.

  The laser driving circuit 8 modulates the current for driving the laser light source in accordance with the recording pulse, and performs recording in the corresponding sector (S5). The recording operation from S3 to S5 is repeated until a predetermined number of sectors have been recorded (Yes in S6).

  As a result, even when a test signal having the same pattern is overwritten on the same track, the phase relationship between the new recording mark and the old recording mark changes randomly from sector to sector. Therefore, mark distortions in various states shown in FIGS. 11 to 14 exist with an equal probability.

  After recording the test signal, the optical head 9 reproduces the corresponding sector (S7), and the reproduction signal processing circuit 11 performs equalization and binarization of the reproduction signal. The edge timing detection circuit 12 slices the binarized reproduction signal and detects the signal inversion interval (S8), thereby measuring the edge interval of the recording mark. The measured edge interval is stored in a memory (not shown) in the system control circuit 2 (S9). The processes from S7 to S9 are repeated for all the sectors on which test recording has been performed (until S10 becomes Yes).

  Thereafter, the system control circuit 2 calculates an average of the measured values of the edge interval accumulated in the memory (S11). As described above, in S4, since the recording start point of the test signal is recorded by being shifted at random for each sector, the edge interval shift (i.e., the influence of various mark distortions as shown in FIGS. 11 to 14) The influences of Δ1 and Δ2 in FIGS. 11 to 14 are averaged. Therefore, the average value of the edge interval calculated in S11 does not have a bias due to the phase relationship with the previous data pattern. As a result, it is possible to obtain an ideal edge interval in the same state as when an actual information signal is overwritten.

  Next, a difference between the edge interval calculated from the reproduced signal obtained by reproducing the test recording result and the edge interval of the test signal (for example, in the case of the test signal as shown in FIGS. 11 to 14, the calculated edge interval). The difference between the time corresponding to and 15T is obtained (S12). Then, the edge position of the recording pulse (for example, the leading edge of the recording pulse for recording the 3T mark in the examples shown in FIGS. 11 to 14) is determined as a position corrected by the above difference (S13). The edge correction amount is set in the recording pulse edge adjustment circuit 7 (S14), and the test recording is finished. Thereafter, when the information signal is actually recorded, the recording is performed according to the edge position of the recording pulse set by the recording pulse edge adjusting circuit 7, so that the recording mark can be formed at an ideal edge position.

  As described above, in the present embodiment, the recording start point of the test signal is randomly shifted for each sector, test recording is performed in a plurality of sectors, and the average value of the edge intervals of the recording marks obtained from the reproduction signal is calculated. As a result, test recording can be performed in which the edge position of the recording mark is accurately determined without deviation, and more accurate information signal recording can be performed.

  In the above description, an example in which a random shift of the recording start point of the test signal is performed for each sector has been described. However, the recording start point may be shifted randomly each time overwriting is performed. Alternatively, the recording start point may be shifted randomly every time the sector changes and overwriting is performed.

(Second Embodiment)
FIG. 3 is a block diagram showing a schematic configuration of a recording / reproducing apparatus according to the second embodiment of the present invention.

  This recording / reproducing apparatus is an apparatus for recording / reproducing information using the optical disc 1, and includes a spindle motor 10 for rotating the optical disc 1 and a laser light source (not shown), and a laser beam at a desired location on the optical disc 1. And an optical head 9 for focusing the light. The operation of the entire recording / reproducing apparatus is controlled by the system control circuit 22.

  This recording / reproducing apparatus has, as recording means (or recording / erasing means), an edge test signal generation circuit 4 for generating a test signal for determining the edge position of a recording pulse, and binarization according to the information signal to be recorded A modulation circuit 5 for generating a recorded data signal, a recording signal generation circuit 6 for generating a recording pulse for driving a laser in accordance with the recording data signal, and an edge of a recording pulse output from the recording signal generation circuit 6 And a recording pulse edge adjusting circuit 7 for adjusting the position. Further, a laser driving circuit 8 is provided for modulating a current for driving the laser light source in the optical head 9 in accordance with the recording pulse output from the recording pulse edge adjusting circuit 7.

  In addition, the recording / reproducing apparatus detects a reproduction signal processing circuit 11 that performs waveform processing of a reproduction signal based on reflected light from the optical disc 1 and an edge timing of the reproduction signal in order to reproduce information from the optical disc 1. An edge timing detection circuit 12 and a demodulation circuit 13 for obtaining reproduction information are provided.

  The recording / reproducing apparatus of this embodiment generates a data pattern for generating a data pattern to be recorded prior to the recording of the test signal on the track on which the test signal is to be recorded, instead of the recording start point shift circuit 3 in the first embodiment. A generation circuit 21 is provided. As this data pattern, data having no correlation with the test signal is used.

  Next, the operation of the recording / reproducing apparatus of this embodiment controlled by the system control circuit 22 will be described with reference to the flowchart of FIG.

  At the time of test recording, first, the optical head 9 seeks a predetermined track on the optical disc 1 (S21), and the system control circuit 22 determines a set value of recording power in the laser drive circuit 8 (S22). Then, the data pattern generation circuit 21 generates a data pattern that has no correlation with the test signal pattern, and sends it to the recording signal generation circuit 6 as a recording data signal (S23). The recording data signal is converted into a recording pulse by the recording signal generating circuit 6, the laser driving current is modulated by the laser driving circuit 8, and recording is performed in the sector to be subjected to test recording later (S24).

  Thereafter, the test signal is sent as a recording data signal from the edge test signal generation circuit 4 to the recording signal generation circuit 6 (S25). Similarly, the recording data signal is converted into a recording pulse by the recording signal generation circuit 6, the laser driving current is modulated by the laser driving circuit 8, and the recording of the data pattern from the data pattern generation circuit 21 is performed in S24. The overwritten sector is overwritten (S26).

  Here, since the data pattern recorded in S24 before overwriting in S26 is a pattern having no correlation with the pattern of the test signal, the degree of overlap between the recording mark by the test signal and the previous recording mark is random. Thus, various mark distortion states shown in FIGS. 11 to 14 exist with an equal probability.

  After recording the test signal, the sector overwritten in S26 is reproduced by the optical head 9 (S27), and the reproduction signal processing circuit 11 equalizes and binarizes the reproduction signal. Then, the edge timing detection circuit 12 slices the binarized signal and detects the signal inversion interval (S28), thereby measuring the edge interval of the recording mark. The measured edge interval is stored in the memory in the system control circuit 22 (S29).

  Next, the system control circuit 22 calculates the average of the measured values of the edge interval (S30). Since the data pattern recorded before overwriting as described above is a pattern having no correlation with the pattern of the test signal, the edge interval shift (i.e., the influence of various mark distortions shown in FIGS. 11 to 14) The influences of Δ1 and Δ2 in FIGS. 11 to 14 are averaged. Therefore, the calculated edge interval value is not biased due to the phase relationship with the previous data pattern. As a result, it is possible to obtain a precise recording mark edge interval.

  Then, the difference between the edge interval calculated from the reproduced signal of the test recorded test signal and the original edge interval of the test signal (for example, in the case of a test signal as shown in FIGS. The difference between the corresponding time and 15T is obtained (S31). Then, the edge position of the recording pulse (for example, the leading edge of the recording pulse for recording the 3T mark in the examples shown in FIGS. 11 to 14) is determined to be a position corrected by the above difference (S32). The edge correction amount is set in the recording pulse edge adjusting circuit 7 (S33), and the test recording is finished. Thereafter, when the information signal is actually recorded, since the recording is performed at the edge position of the recording pulse set by the recording pulse edge adjusting circuit 7, a recording mark can be formed at an ideal edge position.

  As described above, in the present embodiment, prior to the test recording, the data pattern having no correlation with the test signal pattern is recorded on the track on which the test signal is to be recorded, so that the edge position of the recording mark is not biased. Precise determination test recording is possible, and more accurate information signal recording is possible.

  In the present embodiment, the recording start point shift circuit 3 for randomly shifting the recording start point as described in the first embodiment is provided, and the method for recording and reproducing the test signal for a plurality of sectors is used together. For example, since the correlation between the data pattern before the test recording and the data pattern of the test signal is further reduced, it is more preferable in that the edge position of the recording pulse can be determined more precisely.

  In the present embodiment, the data pattern to be recorded prior to recording the test signal is a pattern having no correlation with the test signal pattern. However, a random pattern may be used as the data pattern. In this case, if the system control circuit 22 has random recording information in advance and the recording information is modulated by the modulation circuit 5, the data pattern generation circuit 21 can be omitted, and the recording / reproducing apparatus It is more preferable in that the configuration can be simplified. Alternatively, the same effect can be achieved by a configuration in which random recording information is sent to the system control circuit 22 from an external device (for example, a computer) connected to the recording / reproducing apparatus, and the recording information is modulated by the modulation circuit 5. Is obtained.

  The uncorrelated data pattern recorded prior to recording the test signal may be a data pattern of another test signal having a different pattern cycle. Also in this case, the data pattern generation circuit 21 can be omitted, and the configuration of the recording / reproducing apparatus is simplified, which is more preferable.

  Further, instead of recording a data pattern uncorrelated with the test signal prior to recording the test signal, the test signal is attempted to be recorded by irradiating the optical disc 1 with a laser beam with a certain level of erasing power (Pb). You may make it erase | eliminate all the signals currently recorded on the track. When the optical disc 1 is a phase change type optical disc, the recorded information is erased when the portion of the recording film continuously irradiated with the laser beam having the erasing power Pb is in a crystalline state. Also in this case, it is more preferable in that the data pattern generation circuit 21 can be omitted and the recording / reproducing apparatus can be simplified.

(Third embodiment)
FIG. 5 is a block diagram showing a schematic configuration of a recording / reproducing apparatus according to the third embodiment of the present invention.

  This recording / reproducing apparatus is an apparatus for recording / reproducing information using the optical disc 1, and includes a spindle motor 10 for rotating the optical disc 1 and a laser light source (not shown), and a laser beam at a desired location on the optical disc 1. And an optical head 9 for focusing the light. The operation of the entire recording / reproducing apparatus is controlled by the system control circuit 32.

  This recording / reproducing apparatus includes an edge test signal generation circuit 4 that generates a test signal for determining an edge position of a recording pulse, and a modulation circuit 5 that generates a recording data signal binarized in accordance with an information signal to be recorded. A recording signal generation circuit 6 for generating a recording pulse for driving the laser in accordance with the recording data signal, and a recording pulse edge adjustment circuit 7 for adjusting the edge position of the recording pulse output from the recording signal generation circuit 6; It has. Further, a laser driving circuit 8 is provided for modulating a current for driving the laser light source in the optical head 9 in accordance with the recording pulse output from the recording pulse edge adjusting circuit 7.

  In addition, the recording / reproducing apparatus detects a reproduction signal processing circuit 11 that performs waveform processing of a reproduction signal based on reflected light from the optical disc 1 and an edge timing of the reproduction signal in order to reproduce information from the optical disc 1. An edge timing detection circuit 12 and a demodulation circuit 13 for obtaining reproduction information are provided.

  The above is almost the same as the configuration shown in FIG. 1 in the first embodiment. The recording / reproducing apparatus of the present embodiment is particularly different from the first embodiment in that it does not include the recording start point shift circuit 3 and a bit error rate (abbreviated as BER in the figure) measurement circuit 31 that determines recording power. And a power test signal generation circuit 33 for generating a test signal for determining the recording power.

  Next, the operation of the recording / reproducing apparatus of this embodiment controlled by the system control circuit 32 will be described using the flowchart of FIG.

  At the time of test recording, first, the optical head 9 seeks to a predetermined track on the optical disk 1 (S41), and the system control circuit 32 determines a set value of recording power in the laser drive circuit 8 (S42). Then, the test signal for determining the edge position of the recording pulse (first test signal) is sent from the edge test signal generation circuit 4 to the recording signal generation circuit 6 as a recording data signal (S43). The recording signal generation circuit 6 converts the recording data signal into a recording pulse, and the laser driving circuit 8 modulates the laser driving current based on the recording pulse, and records it in the corresponding sector for test recording (S44).

  After the recording of the test signal, the sector recorded in S44 is reproduced by the optical head 9 (S45), and the reproduction signal processing circuit 11 equalizes and binarizes the reproduction signal. Then, the edge timing detection circuit 12 slices the binarized signal and detects the signal inversion interval (S46), thereby measuring the edge interval of the recording mark and storing the measurement value in the memory in the system control circuit 32. (S47).

  Thereafter, the system control circuit 32 calculates an average of the measured values of the edge interval (S48). Then, the difference between the edge interval calculated from the reproduced signal of the test recorded test signal and the original edge interval of the test signal (for example, in the case of a test signal as shown in FIGS. A difference between the corresponding time and 15T is obtained (S49). Then, the edge position of the recording pulse (for example, the leading edge of the recording pulse for recording the 3T mark in the example shown in FIGS. 11 to 14) is determined as the position corrected by the above difference (S50). The edge correction amount is set in the recording pulse edge adjusting circuit 7 (S51).

  Next, the recording power is set to the minimum value of the power adjustment range (S52), and the power test signal generation circuit 33 sends a power determination test signal (second test signal) to the recording signal generation circuit 6. (S53). Then, based on the recording pulse generated from the test signal, recording is performed in the corresponding sector for performing test recording (S54). Thereafter, the recorded test signal is reproduced (S55), and the reproduction signal processing circuit 11 performs equalization, binarization and the like.

  Then, the bit error rate measuring circuit 31 compares the test signal pattern with the reproduced data pattern to measure the bit error rate (S56), and stores the measured value in the system control circuit 32. Until the recording power reaches the maximum value within the adjustment range (Yes in S57), the recording power is increased stepwise (S58), and the steps from S53 to S56 are repeated.

  Then, the system control circuit 32 refers to the measurement value stored in the memory and calculates the value of the recording power when the bit error rate becomes a certain threshold value (Bth in FIG. 15) (S59). Based on the value, for example, processing for multiplying this value by a certain coefficient is performed to determine an appropriate value of the recording power (S60), and the laser driving circuit 8 sets the recording power to an appropriate value ( S61), the test recording is terminated. According to this method, even when the edge width of the recording pulse is adjusted and the pulse width changes, the information signal can be recorded with the optimum recording power.

  As described above, in the present embodiment, after performing test recording for determining the optimum value of the edge position of the recording pulse, the optimum value of the recording power is set in the state where the edge position of the recording pulse is set to the optimum value. Make a test record to determine. Therefore, even when the edge position of the recording pulse is adjusted and the pulse width changes, the recording power can be optimized, so that the information signal can be recorded with the optimum edge position and recording power, and more precise. An excellent effect is obtained in that an information signal can be recorded.

  In this embodiment, the recording power at the time of determining the edge position is set to a predetermined value in S42. However, if a step of performing test recording to determine the value of this recording power is added before S42. It is more preferable because the optimum edge position and recording power of the recording pulse can be determined more precisely.

  In the present embodiment, as described in the first embodiment, a method for determining the optimum edge position of the recording pulse by randomly recording the recording start point and recording / reproducing the test signal from a plurality of sectors. Is more preferable in that test recording for accurately determining the edge position of the recording mark without deviation is possible.

  Further, in this embodiment, as described in the second embodiment, a data pattern that is not correlated with the test signal pattern in advance is recorded on the track on which the test signal for determining the edge position of the recording pulse is recorded. Use of a recording method in combination is more preferable because test recording for accurately determining the edge position of the recording mark without deviation is possible.

  Further, in the present embodiment, random polarity inversion of the recording data signal is prohibited only when recording the test signal for determining the edge position of the recording pulse as in the fifth embodiment described later. Use of a recording method in combination is more preferable in that the number of rewritable times of the optical disk can be improved and a precise information signal can be recorded.

(Fourth embodiment)
The configuration of the recording / reproducing apparatus in the fourth embodiment of the present invention is the same as the configuration shown in FIG. 5 in the third embodiment, but the control by the system control circuit 32 is different.

  Here, the operation of the recording / reproducing apparatus according to the present embodiment controlled by the system control circuit 32 will be described with reference to the flowchart of FIG. 7 and FIG.

  At the time of test recording, first, the optical head 9 seeks to a predetermined track on the optical disc 1 (S71), and the system control circuit 32 sets the edge position of the recording pulse in the recording pulse edge adjustment circuit 7 to a predetermined position. (S72).

  Next, the recording power is set to the minimum value of the power adjustment range (S73), and a power determination test signal (first test signal) is sent from the power test signal generation circuit 33 to the recording signal generation circuit 6 ( In step S74, recording is performed in the sector in which test recording is performed (S75).

  Next, the recorded test signal is reproduced (S76), and the reproduction signal processing circuit 11 performs equalization, binarization and the like. The bit error rate measurement circuit 31 compares the test signal pattern with the reproduced data pattern to measure the bit error rate (S77), and stores the measurement value in the system control circuit 32. Until the recording power reaches the maximum value within the adjustment range (Yes in S78), the recording power is increased stepwise (S79), and the processes from S74 to S77 are repeated.

  Then, the system control circuit 32 calculates the power at which the bit error rate becomes a constant threshold value (Bth in FIG. 15) based on the accumulated measurement value (S80). The recording power is determined from the power (S81), and the recording power is set by the laser drive circuit 8 (S82).

  Next, a test signal for determining the edge position of the recording pulse (second test signal) is sent from the edge test signal generation circuit 4 to the recording signal generation circuit 6 as a recording data signal (S83). The recording signal generation circuit 6 converts this recording data signal into a recording pulse. The laser drive circuit 8 performs recording on the corresponding sector for test recording by modulating the laser drive current based on the recording pulse from the recording signal generation circuit 6 (S84).

  After recording the test signal, the corresponding sector is reproduced by the optical head 9 (S85), and the reproduction signal processing circuit 11 equalizes and binarizes the reproduction signal. Then, the edge timing detection circuit 12 slices the binarized signal and detects the signal inversion interval (S86), thereby measuring the edge interval of the recording mark and storing the measurement value in the memory in the system control circuit 32. (S87).

  Thereafter, the system control circuit 32 calculates the average of the measured values of the edge interval accumulated in the memory (S88). Then, the difference between the edge interval calculated from the reproduced signal of the test recorded test signal and the original edge interval of the test signal (for example, in the case of a test signal as shown in FIGS. The difference between the corresponding time and 15T is obtained (S89). Then, the edge position of the recording pulse (for example, the leading edge of the recording pulse for recording the 3T mark in the example shown in FIGS. 11 to 14) is determined as a position corrected by the above difference (S90). The edge correction amount is set in the recording pulse edge adjustment circuit 7 (S91), and the test recording is finished. By this method, even when the recording power is adjusted, the information signal can be recorded at the optimum edge position of the recording pulse.

  As described above, in this embodiment, after performing test recording for determining the recording power to an appropriate value, the edge position of the recording pulse is determined with the recording power set to the appropriate value. Make a test record. Thereby, even when the recording power is adjusted and the irradiation energy of the laser light is changed, the information signal can be recorded at the optimum edge position of the recording pulse. As a result, an excellent effect can be obtained in that a more precise information signal can be recorded.

  In this embodiment, the edge position when determining the recording power is set to a predetermined value in S72. However, if a step of performing test recording for determining the edge position is added before S72, recording is performed. This is more preferable because the optimum edge position and recording power of the pulse can be determined more precisely.

  Further, in the present embodiment, as described in the first embodiment, a method for determining the optimum edge position of the recording pulse by randomly shifting the recording start point and recording / reproducing a test signal from a plurality of sectors. When used in combination, it is more preferable in that test recording for accurately determining the edge position of the recording mark without deviation is possible.

  Further, in this embodiment, as described in the second embodiment, a data pattern that is not correlated with the test signal pattern in advance is recorded on the track on which the test signal for determining the edge position of the recording pulse is recorded. Use of a recording method in combination is more preferable because test recording for accurately determining the edge position of the recording mark without deviation is possible.

  Further, in the present embodiment, random polarity inversion of the recording data signal is prohibited only when recording the test signal for determining the edge position of the recording pulse as in the fifth embodiment described later. Use of a recording method in combination is more preferable in that the number of rewritable times of the optical disk can be improved and a precise information signal can be recorded.

  Whether to use the method of the present embodiment or the method of the third embodiment described above when performing test recording to determine the optimum recording power and the optimum edge position of the recording pulse depends on whether the optical disk to be recorded is used. What is necessary is just to select according to a structure, a recording density, a modulation system, etc. For example, in the case of an optical disc in which jitter or bit error rate fluctuations are sensitive to edge position fluctuations, the method of this embodiment is preferred, and in an optical disc in which jitter or bit error rate fluctuations are sensitive to recording power fluctuations. The method of the third embodiment is preferred.

  In general, the test recording for determining the edge position of the recording mark and the test recording for determining the recording power require a more complicated configuration for the recording / reproducing apparatus. Therefore, for example, when adjusting (shipping) the recording / reproducing apparatus, test recording for determining the edge position is performed using an external measuring instrument such as a time interval analyzer, and thereafter only test recording for determining recording power is performed. When performed, the method of the third embodiment is preferable in that the configuration of the recording / reproducing apparatus can be simplified.

(Fifth embodiment)
FIG. 8 is a block diagram showing a schematic configuration of a recording / reproducing apparatus according to the fifth embodiment of the present invention.

  This recording / reproducing apparatus is an apparatus for recording / reproducing information using the optical disc 1, and includes a spindle motor 10 for rotating the optical disc 1 and a laser light source (not shown), and a laser beam at a desired location on the optical disc 1. And an optical head 9 for focusing the light. The operation of the entire recording / reproducing apparatus is controlled by the system control circuit 52.

  The recording / reproducing apparatus includes an edge test signal generation circuit 4 that generates a test signal for test recording, a modulation circuit 5 that generates a recording data signal binarized in accordance with an information signal to be recorded, and a recording data signal. In response, a recording signal generation circuit 6 that generates a recording pulse for driving the laser and a recording pulse edge adjustment circuit 7 that adjusts the edge position of the recording pulse output from the recording signal generation circuit 6 are provided. Further, a laser drive circuit 8 is provided for modulating a current for driving a laser light source (not shown) in the optical head 9 in accordance with a recording pulse output from the recording pulse edge adjusting circuit 7.

  In addition, the recording / reproducing apparatus detects a reproduction signal processing circuit 11 that performs waveform processing of a reproduction signal based on reflected light from the optical disc 1 and an edge timing of the reproduction signal in order to reproduce information from the optical disc 1. An edge timing detection circuit 12 and a demodulation circuit 13 for obtaining reproduction information are provided.

  The recording / reproducing apparatus further inverts the polarity of the recording data signal from the polarity inversion circuit 54 and the output destination of the signal sent from the modulation circuit 5 or the edge test signal generation circuit 4 to the recording signal generation circuit 6. A selection circuit 55 having a built-in switch for switching between the circuit 54 and a polarity inversion control circuit 53 for prohibiting and releasing random polarity inversion is provided.

  Next, the operation of the recording / reproducing apparatus of this embodiment will be described using the flowchart of FIG.

  At the time of test recording, first, the polarity inversion control circuit 53 performs control to fix the output of the selection circuit 55 to the recording signal generation circuit 6 side, and all the data from the edge test signal generation circuit 4 passes through the polarity inversion circuit 54. (S101). Thereby, the polarity inversion of the recording data signal is prohibited.

  Next, the optical head 9 seeks to a predetermined track on the optical disk 1 (S102), and the system control circuit 52 sets the recording power in the laser drive circuit 8 to a predetermined value (S103). Then, the edge test signal generation circuit 4 sends a test signal to the selection circuit 55 as a recording data signal (S104). Here, since the selection circuit 55 is switched to the recording signal generation circuit 6 side in S101, all the test signals sent from the edge test signal generation circuit 4 do not pass through the polarity inversion circuit 54. Input to the generation circuit 6.

  The recording signal generation circuit 6 converts the input test signal into a recording pulse for driving the laser in the same manner as in the above-described embodiment. The laser drive circuit 8 modulates the laser drive current based on this recording pulse, and records it in the corresponding sector for test recording (S105).

  After recording the test signal, the optical head 9 reproduces the sector on which the test recording was performed (S106), and the reproduction signal processing circuit 11 performs equalization and binarization of the reproduction signal. Further, the edge timing detection circuit 12 slices the binarized signal and detects the signal inversion interval (S107). Based on the detected inversion interval, the system control circuit 52 measures the edge interval of the recording mark and accumulates the measured value in the memory in the system control circuit 52 (S108).

  Next, the system control circuit 52 calculates the average of the measured values of the edge interval accumulated in the memory (S109). The system control circuit 52 determines the difference between the edge interval calculated in S109 and the original edge interval of the test signal (for example, in the case of a test signal as shown in FIGS. 11 to 14, a time corresponding to the calculated edge interval). And the difference between 15T) (S110). Then, the edge position of the recording pulse (for example, the leading edge of the recording pulse for recording the 3T mark in the examples shown in FIGS. 11 to 14) is determined to be a position corrected by the above difference (S111). The edge correction amount is set in the recording pulse edge adjustment circuit 7 (S112).

  Finally, the polarity reversal control circuit 53 cancels the polarity reversal prohibition set in S101 so that the switch in the selection circuit 55 can be switched randomly for each sector (S113), and the test recording is completed.

  When the information signal is actually recorded after the test recording, the switch in the selection circuit 55 is randomly switched for each sector. As a result, the information signal is inverted from the modulation circuit 5 via the polarity inversion circuit 54 and sent to the recording signal reproduction circuit 6, and the modulation circuit 5 does not pass through the polarity inversion circuit 54. One of the non-inverted states sent directly to the recording signal reproduction circuit 6 is randomly selected for each sector. As a result, even when a similar information signal is repeatedly recorded in the same sector, damage to a specific position of the recording film of the optical disc 1 is avoided. Note that the switching of the selection circuit 55 at the time of recording the information signal is not limited to each sector but may be performed for each overwrite.

  As described above, in this embodiment, the front end of the recording mark is determined when determining the edge position of the recording mark by performing control to prohibit random polarity inversion of the recording data signal only when performing test recording. The edge and the trailing edge can be distinguished from each other, and a precise information signal can be recorded. Moreover, when actually recording an information signal, it is possible to improve the number of times that the optical disk can be rewritten by controlling the polarity of the recording data signal to be randomly inverted for each sector or each overwrite. Excellent effect is obtained.

  In S101, contrary to the above, the polarity inversion control circuit 53 selects the selection circuit 55 so that all the test signals sent from the edge test signal generation circuit 4 are sent to the polarity inversion circuit 54 and the polarity is inverted. The switching control of these switches may be performed. In short, it is sufficient that the polarity of the recording data signal is always the same during a series of test recordings.

  In the present embodiment, the configuration and method for determining the optimum edge position of the recording pulse by the test recording provided with the edge test signal generation circuit 4 have been described. However, as in the third embodiment, the power test signal generation is performed. The circuit 33 may be further provided, and a method for determining the recording power may be used in combination. In this case, in the process of determining the recording power, it is preferable to perform control so as to cancel the prohibition of polarity inversion. This is because in test recording to determine the recording power, there is a high possibility that recording will be performed at a higher recording power than test recording to determine the edge position of the recording pulse or normal information signal recording. This is because it is possible to suppress the deterioration of the recording film when the recording is repeatedly performed on the test track.

  In the present embodiment, as described in the first embodiment, a method for determining the optimum edge position of the recording pulse by randomly recording the recording start point and recording / reproducing the test signal from a plurality of sectors. Is more preferable in that test recording for accurately determining the edge position of the recording mark without deviation is possible.

  Further, in this embodiment, as described in the second embodiment, a data pattern that is not correlated with the test signal pattern in advance is recorded on the track on which the test signal for determining the edge position of the recording pulse is recorded. Use of the recording method in combination is more preferable in that test recording for accurately determining the edge position of the recording mark without deviation is possible.

(Sixth embodiment)
The sixth embodiment of the present invention uses the recording / reproducing apparatus having the configuration shown in FIG. 1 in the first embodiment described above, but uses an optical disk of Z-CLV format as the optical disk 1. Hereinafter, the operation of the recording / reproducing apparatus of this embodiment will be described with reference to the flowchart of FIG. 10 and FIG.

  At the time of test recording, first, the optical head 9 seeks to a track near the innermost periphery of any zone of the recording area on the optical disc 1 (S121), and the system control circuit 2 determines the recording power in the laser drive circuit 8 as follows. The set value is set to a predetermined value (S122). Then, the edge test signal generation circuit 4 sends the test signal to the recording signal generation circuit 6 as a recording data signal (S123). The recording signal generation circuit 6 converts the recording data signal into a recording pulse, and the laser driving circuit 8 modulates the driving current of a laser light source (not shown) of the optical head 9 to perform test recording in the corresponding sector. Perform (S124).

  After recording the test signal, the optical head 9 reproduces the sector on which the test recording has been performed (S125), and the reproduction signal processing circuit 11 equalizes and binarizes the reproduction signal. Then, the edge timing detection circuit 12 slices the binarized signal and detects the signal inversion interval (S126), thereby measuring the edge interval of the recording mark, and a memory (not shown) in the system control circuit 2. ) Is stored (S127). Further, the system control circuit 52 calculates the average value of the edge intervals from the measurement values stored in the memory (S128).

  Then, the system control circuit 2 corresponds to the difference between the edge interval calculated in S128 and the original edge interval of the test signal (for example, in the case of the test signal as shown in FIGS. 11 to 14, it corresponds to the calculated edge interval). The difference between the time to perform and 15T is obtained (S129). Then, the edge position of the recording pulse (for example, the leading edge of the recording pulse for recording the 3T mark in the examples shown in FIGS. 11 to 14) is determined as the position corrected by the above difference (S130). The edge correction amount is set in the recording pulse edge adjustment circuit 7 (S131).

  Next, a comparative experiment conducted to confirm the effect of this embodiment will be described. In this experiment, instead of measuring the bit error rate, the jitter of the reproduced signal was measured by a time interval analyzer. A time interval analyzer was also used to detect the edge timing of the reproduced signal.

  Table 1 shows the zone format of the substrate of the optical disc 1 used in this experiment. In this format, a recording area having a radius of 25.0 mm to 50 mm (that is, an area in which information signals are actually recorded) is divided into 10 zones, and a Z-CLV format in which the rotation speed is constant in each zone. The clock cycle is the same over the entire recording area. In this embodiment, the format is such that the linear velocity is the same at the innermost circumference of each zone, but the linear velocity need not necessarily be the same at the innermost circumference of each zone.

  For the substrate of the optical disc 1, a polycarbonate resin having a diameter of 120 mm and a thickness of 0.6 mm was used. This resin substrate was preformatted with uneven phase pits as address information, and recording tracks were formed in the sector area. The track pitch is 1.2 μm. A protective film, a phase change recording film, a protective film, and a reflective film were formed on the substrate by a sputtering method, and a protective substrate was adhered thereon.

  ZnS—SiO 2 was used as the protective film, Te—Sb—Ge was used as the phase change recording film, and Al was used as the reflective film. Then, the optical disk 1 was rotated by the spindle motor 10 at the rotational speed shown in Table 1, and laser light having a wavelength of 660 nm was focused by an objective lens having a numerical aperture (NA) of 0.6 to perform recording / reproduction. The full width at half maximum of the spot size is 0.62 μm.

  The power of the laser beam at the time of test recording was Pp = 11 mW, Pb = 5 mW, and Pr = 1 mW. As a modulation method of recording information, (8-16) pulse width modulation used in DVD was used. The shortest 3T mark length was 0.42 μm.

  Prior to recording the information signal, test recording was performed on a track near the innermost periphery of the zeroth zone to determine the edge position of the recording pulse. The determination method followed the procedure shown in the flowchart of FIG. 2 in the first embodiment.

  However, the front end of the edge position of the recording pulse is the length of the mark to be recorded (3T mark, 4T mark, 5T or more mark) and the length of the space immediately before the mark (3T space, 4T space, 5T or more space). ) And 9 combinations were determined respectively. The trailing edge of the edge position of the recording pulse is the length of the mark to be recorded (3T mark, 4T mark, 5T mark or more) and the length of the immediately following space (3T space, 4T space, 5T or more space). Nine combinations were determined. The edge position adjustment accuracy is 0.5 ns.

  The edge position adjustment values for the 3T mark, 4T mark, and 5T mark or more are made different because the 3T mark and the 4T mark are in a so-called brush tip recording state, so the mark length is smaller than the spot size. Therefore, it is necessary to make the edge position different from the case of the mark length of 5T or more. The adjustment value of the edge position is changed in the 3T space, the 4T space, and the space of 5T or more because the influence of the thermal interference between the marks cannot be ignored in the 3T space and the 4T space.

  Next, based on the edge position of the recording pulse determined in this test recording, (8-16) pulse width modulation is performed on the track near the innermost circumference (namely, radius 25.0 mm) and the track near the outermost circumference of the zeroth zone. The random information signal was overwritten and recorded 10 times, and the jitter of the reproduced signal was measured.

  Next, in the same manner as described above, test recording was performed on a track near the outermost periphery (namely, radius 27.5 mm) of the zeroth zone, and the edge position of the recording pulse was determined. Then, based on the edge position of the recording pulse recorded in this test recording, (8-16) random information signal of pulse width modulation is performed 10 times on the track near the innermost circumference and the track near the outermost circumference of the 0th zone. Overwrite recording was performed, and the jitter of the reproduced signal was measured. Table 2 shows the above jitter measurement results.

  As shown in Table 2, it was found that the jitter of the random information signal is better near the outermost zone of the zone regardless of whether the test recording is performed on the track near the innermost zone or the outermost zone of the zone. This is because the recording linear density is lower in the outermost zone. For example, as shown in Table 1, in the 0th zone, the shortest mark length on the outermost circumference is 1.1 times the innermost circumference.

  Also, jitter when test recording is performed at the innermost zone and random information signals are recorded at the outermost zone is almost the same as jitter when test recording is performed at the outermost zone and random information signals are recorded at the outermost zone. It is. On the other hand, the jitter when the test recording is performed at the innermost periphery of the zone and the random information signal is recorded at the innermost periphery is the jitter when the test recording is performed at the innermost periphery of the zone and the random information signal is recorded at the innermost periphery. Also increased by about 1%.

  The reason is considered as follows. Since the recording linear density is low at the outermost zone of the zone, the degree of change in the jitter value with respect to the deviation of the edge position of the recording pulse is small when test recording is performed. For this reason, an adjustment error is likely to occur when the edge position is adjusted by test recording, and it can be assumed that the influence appears as an increase in jitter value when recording is performed on the innermost circumference.

  As described above, in the present embodiment, the test signal is recorded with the recording linear density substantially equal to the recording linear density of the information signal in the innermost track of each zone of the Z-CLV disc, and the edge position of the recording pulse is recorded. By determining the value, it is possible to obtain a good jitter (or bit error rate) from the innermost circumference to the outermost circumference of each zone, and an excellent effect is obtained in that precise information signal recording is possible. .

  In this embodiment, the test recording is performed in the vicinity of the innermost circumference in the zone of the recording area of the optical disk, that is, the area in which the information signal is recorded, but the area in the vicinity of the innermost circumference of at least one zone of the optical disk A test recording area may be provided and test recording may be performed in the area.

  Further, as shown in Table 3, test recording areas are provided on the inner and outer peripheral sides of the recording area on the optical disc, and the recording linear density of each area is the recording linear density at the innermost periphery of each zone. Similar effects can be obtained even when the recording linear densities are substantially equal.

  Further, in the present embodiment, the test recording for determining the edge position of the recording pulse has been described. However, for the test recording for determining the recording power, the information signal in the innermost track of each zone of the recording area is used. If the test recording is performed with a recording linear density substantially equal to the recording linear density of each zone, the optimum recording power can be set from the innermost circumference to the outermost circumference of each zone, and the recording of precise information signals becomes possible. Is obtained.

  Further, in the present embodiment, as described in the first embodiment, the method of determining the optimum edge position of the recording pulse by shifting the recording start point at random and recording / reproducing the test signal from a plurality of sectors can be used together. For example, it is more preferable in that test recording for accurately determining the edge position of the recording mark without deviation is possible.

  In this embodiment, as described in the second embodiment, a data pattern having no correlation with the test signal pattern is recorded in advance on the track for recording the test signal for determining the edge position of the recording pulse. If this method is used in combination, it is more preferable in that test recording that accurately determines the edge position of the recording mark without deviation is possible.

  Further, in the present embodiment, as in the fifth embodiment, a method for recording by prohibiting random polarity inversion of the recording data signal only when recording the test signal for determining the edge position of the recording pulse. Is more preferable in that the number of rewritable times of the optical disk can be improved and a precise information signal can be recorded.

  In the first to sixth embodiments, it is desirable that the test recording is performed at least at the time of adjusting the recording / reproducing apparatus, at the time of starting the recording / reproducing apparatus, when a certain time has elapsed since the activation, When the optical disk is replaced, when the bit error rate of the optical disk exceeds a predetermined value, the temperature of the usage environment changes.

  By performing test recording at the time of adjusting the recording / reproducing apparatus, it is possible to compensate for a variation factor between the recording / reproducing apparatuses. Further, by performing test recording when the recording / reproducing apparatus is activated and when a predetermined time has elapsed since the activation, the fluctuation factors of the recording / reproducing apparatus itself can be compensated. In addition, by performing test recording at the time of exchanging the optical disk, it is possible to compensate for the variation factors between the optical disks. Further, by performing test recording when the bit error rate of the optical disc exceeds a predetermined value, the fluctuation factors of the optical disc itself can be compensated. Further, by performing test recording when the temperature of the usage environment changes, it is possible to compensate for fluctuation factors due to the temperature dependence of the recording / reproducing apparatus and the optical disc.

  In the first to sixth embodiments, the edge position of the recording pulse is determined by recording a specific test signal and measuring the edge interval of the reproduction signal. However, the edge position is changed. Measure the bit error rate (or jitter) by recording multiple types of test signals (for example, multiple types of random signals), and record the recording pulse set by the test signal with the minimum bit error rate (or jitter). The same effect can be obtained by the method of determining the edge position as the optimum value.

  In the above first to sixth embodiments, in order to determine the edge position of the recording pulse, the difference between the edge interval of the recording mark measured by recording a specific test signal and the optimum edge interval is determined. Was corrected by an edge position adjustment circuit. However, a plurality of types of test signals, in which the edge position of the recording pulse is changed in stages, are recorded, and the edge interval of the recording mark is measured for each test signal, and the recording with the test signal that provides the most optimal edge interval The same effect can be obtained by setting the edge position of the pulse as an optimum value in the edge position adjustment circuit.

  In the first to sixth embodiments, the edge interval of the recording mark is measured by the edge timing detection circuit, and the measured edge interval is accumulated and the average value is calculated by the system control circuit. These processes may be performed by a measuring device outside the recording / reproducing apparatus, such as a time interval analyzer.

  In the first to sixth embodiments, the test signal generation circuit is provided to generate the test signal. However, a signal modulated by generating a specific information signal from the system control circuit may be used as the test signal. good. This eliminates the need for providing a separate test signal generation circuit, thereby reducing the size of the apparatus. Further, an error correction code added to the test signal or an interleave process may be performed, and the bit error rate may be measured after demodulation and error correction.

  Further, the number of layers, the configuration, and the material of the optical disk are not limited to the above, and any of the above methods can be used as long as the medium has different optical characteristics between the recording mark and the non-marked part, such as a magneto-optical material and a dye material. Can be applied. However, in the case of an optical disk using a phase change material as a recording film, since the optical absorption differs between crystal and amorphous, a particularly great effect can be obtained by the above test recording method.

  In addition, the recording power, linear velocity, modulation method, recording density, length / position of each pulse, test signal pattern, etc. are not limited to those shown in the present embodiment, but depending on recording conditions and media. It goes without saying that it is possible to set an appropriate one. Further, the bit error rate measurement may be replaced with a jitter measurement, and the jitter measurement may be replaced with a bit error rate measurement.

  As described above, according to the optical information recording apparatus of the present invention, the influence of mark distortion on the edge interval of the recording mark is averaged during the test recording. Can be determined precisely. As a result, an optical information recording apparatus capable of recording a more precise information signal can be provided.

  In addition, according to the optical information recording method of the present invention, it is possible to optimize both the recording power and the edge position of the recording pulse by the test recording, so that more accurate information signal recording can be performed.

  Also, according to the optical information recording medium of the present invention, a good jitter or bit error rate can be obtained from the innermost circumference to the outermost circumference of each zone, and precise information signals can be recorded.

The block diagram which shows the structure of the recording / reproducing apparatus which concerns on the 1st and 6th embodiment of this invention Flowchart for explaining the operation of the recording / reproducing apparatus according to the first embodiment. The block diagram which shows the structure of the recording / reproducing apparatus which concerns on the 2nd Embodiment of this invention. Flowchart for explaining the operation of the recording / reproducing apparatus according to the second embodiment. The block diagram which shows the structure of the recording / reproducing apparatus which concerns on 3rd, 4th embodiment of this invention Flowchart for explaining the operation of the recording / reproducing apparatus according to the third embodiment. The flowchart explaining operation | movement of the recording / reproducing apparatus which concerns on the 4th Embodiment of this invention. The block diagram which shows the structure of the recording / reproducing apparatus which concerns on the 5th Embodiment of this invention. Flowchart for explaining the operation of the recording / reproducing apparatus according to the fifth embodiment. The flowchart explaining operation | movement of the recording / reproducing apparatus which concerns on the 6th Embodiment of this invention. FIG. 3 is an explanatory diagram showing an example of a state of a track before performing test recording, a test signal for test recording, and a state of the track when test recording is performed based on the test signal in a conventional optical disc FIG. 3 is an explanatory diagram showing another example of a state of a track before performing test recording, a test signal for test recording, and a state of the track when test recording is performed based on the test signal in a conventional optical disc In the conventional optical disc, description is given showing still another example of the state of a track before performing test recording, a test signal for test recording, and the state of the track when test recording is performed based on the test signal Figure In the conventional optical disc, description is given showing still another example of the state of a track before performing test recording, a test signal for test recording, and the state of the track when test recording is performed based on the test signal Figure A graph showing the relationship between the recording peak power Pp and the bit error rate when a periodic signal of the shortest mark is recorded by changing the recording pulse width in a conventional optical disc.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2.2 / 32/52 System control circuit 3 Recording start point shift circuit 4 Edge test signal generation circuit 5 Modulation circuit 6 Recording signal generation circuit 7 Recording pulse edge adjustment circuit 8 Laser drive circuit 9 Optical head 10 Spindle motor 11 Playback Signal processing circuit 12 Edge timing detection circuit 13 Demodulation circuit 21 Data pattern generation circuit 31 Bit error rate measurement circuit 33 Power test signal generation circuit 54 Polarity inversion circuit 55 Selection circuit 53 Polarity inversion control circuit 111 Track 112/115 Recording mark 114/116 Mark distortion

Claims (15)

In an optical information recording method using a rewritable optical information recording medium and performing test recording before recording an information signal on the optical information recording medium,
Setting the recording power of the light source to an initial value and recording the first test signal on the optical information recording medium;
Determining an appropriate value of the edge position of the recording pulse based on the result of reproducing the first test signal recorded in the step (a) from the optical information recording medium;
Setting the edge position of the recording pulse to the appropriate value determined in step (b), and recording a second test signal on the optical information recording medium (c);
(D) determining an appropriate value of recording power based on a result of reproducing the second test signal recorded in step (c) from the optical information recording medium,
In step (a), test recording is performed by randomly shifting the start point of test recording to a plurality of sectors of the optical information recording medium for each sector,
In the step (b), an appropriate value of an edge position of a pulse of the recording data signal is determined based on an average of results obtained by reproducing the first test signal from the plurality of sectors. Information recording method. Prior to step (a),
Setting the edge position of the recording pulse to a predetermined value and recording the second test signal on the optical information recording medium (e-1);
Further including a step (e-2) of determining an appropriate value of the recording power based on a result of reproducing the second test signal recorded in the step (e-1) from the optical information recording medium,
The optical information recording method according to claim 1, wherein an appropriate value of the recording power determined in the step (e-2) is used as an initial value of the recording power in the step (a). The step (b) includes a step of comparing an edge interval of the first test signal with an edge interval of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium. Item 3. The optical information recording method according to Item 1 or 2 . The step (b) includes a step of measuring one of a bit error rate and a jitter of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium, and the measurement result is minimum. the optical information recording method according to claim 1 or 2 for determining the edge positions of comprising such a recording pulse as a proper value. The step (d) includes a step of measuring either a bit error or a jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium, and the measurement result is a predetermined value. 3. The optical information recording method according to claim 1, wherein an appropriate value of the recording power is determined based on a recording power value as follows. The step (e-2) includes a step of measuring either a bit error or a jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium, and the measurement result is predetermined. The optical information recording method according to claim 2 , wherein an appropriate value of the recording power is determined based on a value of the recording power that is equal to or less than the above value. In an optical information recording method using a rewritable optical information recording medium and performing test recording before recording an information signal on the optical information recording medium,
A step (a) of setting an edge position of a recording pulse to an initial position and recording a first test signal on an optical information recording medium;
Determining an appropriate value of the recording power of the light source based on the result of reproducing the first test signal recorded in the step (a) from the optical information recording medium;
Recording a second test signal on the optical information recording medium based on the recording power determined in the step (b) (c);
(D) determining an appropriate value of an edge position of a recording pulse based on a result of reproducing the second test signal recorded in the step (c) from the optical information recording medium,
In the step (c), test recording is performed by randomly shifting the start point of test recording to a plurality of sectors of the optical information recording medium for each sector,
In the step (d), an appropriate value of an edge position of a pulse of the recording data signal is determined based on an average of results obtained by reproducing the second test signal from the plurality of sectors. Information recording method. Prior to step (a),
Setting the recording power to a predetermined value and recording the first test signal on the optical information recording medium (e-1);
A step (e-2) of determining an appropriate value of the edge position of the recording pulse based on the result of reproducing the first test signal recorded in the step (e-1) from the optical information recording medium. Including
8. The optical information recording method according to claim 7, wherein an appropriate value of the edge position of the recording pulse determined in the step (e-2) is used as an initial position of the edge position of the recording pulse in the step (a). 9. The optical information recording method according to claim 8 , wherein, in the step (e-1), a recording start point on the optical information recording medium is randomly shifted at at least one timing for each sector and each overwrite. 9. The optical information recording method according to claim 8 , further comprising a step of recording a data pattern having no correlation with a test signal in an area where test recording is performed on the optical information recording medium before the step (e-1). . The step (b) includes a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium, and the measurement result is a predetermined value. The optical information recording method according to any one of claims 7 to 10 , wherein an appropriate value of the recording power is determined based on a value of the recording power that is less than or equal to the value. The step (d) includes a step of comparing an edge interval of the second test signal with an edge interval of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium. Item 11. The optical information recording method according to any one of Items 7 to 10 . The step (d) includes a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the second test signal from the optical information recording medium, and the measurement result is minimum. The optical information recording method according to claim 7, wherein an edge position of such a recording pulse is determined as an appropriate value. The step (e-2) includes comparing the edge interval of the first test signal with the edge interval of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium. The optical information recording method according to claim 8 . The step (e-2) includes a step of measuring either a bit error rate or jitter of a reproduction signal obtained by reproducing the first test signal from the optical information recording medium, and the measurement result is 9. The optical information recording method according to claim 8 , wherein an edge position of the recording pulse that is minimized is determined as an appropriate value.

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