JP2004199848A - Information recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve the high density of recorded information and a high transfer speed and to improve reliability by controlling a recording signal based on recording characteristics especially by the combination of a recording medium and a recording device regarding an information recording/reproducing device for recording/reproducing a digital signal in/from a recording medium such as an optical disk. <P>SOLUTION: A plurality of recording patterns are recorded on a recording medium, the edge position of a reproducing signal from the plurality of recording patterns is measured, the amount of shifting between the edge position and a laser pulse position during writing is measured, a data table regarding the amount of shifting measured for each of the plurality of recording patterns is created, and these operations are carried out for each exchange of a recording medium. Edge correction with a preceding recording pattern row taken into consideration is carried out. The change of the recording recording device with time is absorbed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for recording / reproducing a digital signal to / from a recording medium such as an optical disk, and more particularly to controlling a recording signal based on recording characteristics of a combination of a recording medium and a recording device, thereby achieving high density recording information. The present invention relates to a recording / reproducing apparatus suitable for realizing high performance, high transfer speed, and improvement in reliability.
[0002]
[Prior art]
An optical disk device is one of means for recording a digital signal on a recording medium. In an optical disk, a laser beam is focused on a recording surface by a lens, the intensity of which is changed according to the information to be recorded, and the reflectivity of a recording film in an area irradiated with the laser beam, or in the case of magneto-optical recording. Information is recorded by changing the magnetization direction by external magnetization or the like. When reproducing the recorded information, irradiate a laser beam of lower intensity than at the time of recording, and detect the change in the amount of light or the polarization plane rotation due to the difference in the magnetization direction from the reflected light from the recording film. Performed by The recording density is mainly determined by the size of the spot of the laser beam condensed on the recording surface, and since the size is as small as about 1 μm at present, high-density recording about 10 times that of a magnetic disk can be realized.
[0003]
Further, the mark length recording method in which information is recorded at positions before and after a recording mark recorded by modulating the irradiation light power is used because two or more data are recorded in one recording mark. This is an effective method for realizing density.
[0004]
As described above, in the mark length recording method for recording and reproducing information on an optical disk at high density, various signal processings are performed at the time of recording and reproducing data in order to realize high reliability of information. .
[0005]
For example, generally, when the irradiation light power at the time of recording is small, the shape of a recording mark formed tends to be unstable. Further, if the recording linear velocity is different, the amount of heat applied per unit area and the heat distribution are changed, so that the shape of the recording mark is different. Therefore, in order to actually perform recording and reproduction by forming a stable recording mark shape, "application of pit edge recording to a PbTbSe film" (Proceedings of the 70th Anniversary of IEICE, p4-176) In, the recording irradiation light pulse is set to be relatively large, and the laser pulse length is shortened during recording so that the mark length does not become excessive according to the linear velocity, or the pulse length of the binarized signal during reproduction is reduced. Adjustments such as shaving.
[0006]
In general, the shape of a recorded mark mainly depends on the recording sensitivity, thermal conductivity, and intensity distribution of a focused laser beam used for recording, wavefront aberration, and the like of the recording medium. When the combination changes, the characteristics change. Further, the level of the irradiation light power at the time of recording on the apparatus side changes with time. This phenomenon is inevitable for a certain range of fluctuation even when an automatic laser power control mechanism (APC) is provided, and this factor causes fluctuation in recording / reproducing characteristics. This change leads to a change in the recording mark length during recording and a change in the pulse interval of the reproduced signal during reproduction.
[0007]
Therefore, when the recording correction amount and the recording optical power are set to predetermined values before shipment of the apparatus, these setting specifications are determined after measuring the recording / reproducing characteristics with a combination of many recording media and recording apparatuses. At this time, in consideration of the range of variation in the recording / reproducing characteristics due to the difference in the combination, in order to guarantee the reliability at the time of detection in all cases, a large margin is given to the recording density, and the recording density is sacrificed.
[0008]
Therefore, in order to absorb the variation in characteristics due to the combination of the recording medium and the recording device, and to increase the recording density, a method has been proposed in which a test pattern is recorded in advance and information for adjusting recording conditions is obtained from a reproduced signal thereof. ing. For example, in the apparatus described in JP-A-61-239441, the irradiation light power level which is a constant value at the time of recording is set. In the apparatus described in JP-A-61-74178, a constant adjustment amount relating to the recording pulse width is set. In the device described in JP-A-61-304427, both of them and the automatic equalization coefficient during reproduction are adjusted simultaneously.
[0009]
In addition, since an optical disk is basically a recording method using thermal diffusion, a phenomenon in which the shape of a recording mark changes due to the diffusion of heat distribution due to a plurality of recording pulses before and after the recording mark (hereinafter referred to as thermal interference). Call) exists. This phenomenon also leads to variations in the pulse interval of the reproduced signal during reproduction. Therefore, it is necessary to consider the influence of the thermal interference in order to perform the optimum correction at the time of recording. As a countermeasure, in the recording method described in JP-A-63-48617, the width of each recording pulse is changed according to the interval to the immediately preceding recording pulse.
[0010]
[Problems to be solved by the invention]
Among the above prior arts, the method of adjusting the recording pulse width according to the interval up to the immediately preceding recording pulse has the following problems.
[0011]
That is, when it is attempted to increase the recording density so that the recording mark shape and the interval between the recording marks are about the same size as the size of the laser spot focused on the recording film surface, the thermal interference of the optical disc is reduced. The range of influence is larger than the shortest recording mark length used. That is, the length of the interval between a plurality of recording pulses of the recording irradiation light pulse affects the amount of change in the edge position of one recording mark. In particular, in the case of a recording medium that has high recording sensitivity with respect to the intensity of laser light and can perform recording with a low laser power, the thermal conductivity is generally large, and the range affected by the thermal interference is large.
[0012]
Further, in the method of adjusting the recording pulse interval, since the information on the adjustment amount uses a preset value, the adjustment amount on the fluctuation of the recording characteristic cannot be changed, and the recording characteristic is shifted from the setting. However, it appears as an error in the adjustment, and the adjustment is not accurate.
[0013]
On the other hand, in the method of obtaining the information for adjusting the recording condition described above, the adjustment amount of the recording irradiation light power and the recording pulse width is a single value, and the recording mark length and fluctuation due to thermal interference cannot be reduced. .
[0014]
Conventionally, as a countermeasure against intersymbol interference components, in the field of communication and magnetic recording, a linear equalizer such as a transversal filter is generally used on the reproduction side. This is to reduce linear intersymbol interference generated by superimposing on a nearby waveform, because the frequency band of the signal reproduction system is narrow and the bottom of the reproduction signal pulse is widened.
[0015]
However, the above-mentioned influence due to thermal diffusion mainly appears as a waveform shift in the time direction during reproduction. This is a non-linear intersymbol interference component that cannot be expressed simply as a linear superposition of basic waveforms according to the recorded information. Therefore, the edge position fluctuation component due to the thermal interference generated at the time of recording cannot be handled by the linear equalizer, and it is actually very difficult for the reproducing side to deal with the interference component in real time.
[0016]
For the above reasons, even if the conventional method can cope with the fluctuation of the recording characteristics, the fluctuation of the recording mark length due to the influence of the thermal interference has not been reduced at all, or the recording mark length due to the influence of the thermal interference has not been reduced. There is an adjustment error in the fluctuation, and it cannot respond to the recording characteristic fluctuation at all. In particular, in mark length recording in magneto-optical recording using a recording medium having a large heat conduction, these fluctuation components are large, and a margin is provided for the fluctuation components, so that the recording density has to be sacrificed greatly.
[0017]
[Means for Solving the Problems]
According to the present invention, in a combination of a recording medium to be recorded / reproduced and a recording apparatus, various recording patterns are recorded in a plurality of areas on the recording medium at necessary timings, and the recorded data is reproduced. The recording characteristics are measured in the above manner, a data table relating to the recording pulse interval adjustment amount is created from the measurement result, and based on the data table, for each recording pulse interval, the immediately preceding data obtained by conversion is obtained. By using a plurality of recording irradiation light pulse intervals, the amounts of adjustment of the leading edge and the trailing edge of the pulse are sequentially obtained and assigned to make the recording irradiation light pulse interval, so that the desired recording mark length and the reproduction signal can be obtained. It is characterized by obtaining a pulse interval. According to the present invention, more accurate edge position control of a recording mark for high-density recording by mark length recording can be realized.
[0018]
In the combination of a recording medium and a recording device for which recording and reproduction are to be performed, its recording characteristics are measured in advance, and before each pulse, the recording pattern sequence immediately before that is also considered for each recording pulse based on the result. By sequentially allocating the correction amounts of the edge and the trailing edge, a difference in recording characteristics due to a combination of a recording medium and a recording device, and a variation in a recording mark length when a recording pattern row is different due to the influence of thermal interference. Can be absorbed.
[0019]
Further, by using a plurality of recording characteristics measured in different regions on the recording medium, it is possible to perform recording correction at a place where the linear velocity is different.
[0020]
In addition, when the use of the apparatus is started, when the recording medium is replaced, and at regular time intervals, or at a timing corresponding to a change in temperature on the recording film and a change in recording irradiation light power, the recording characteristics are measured. By doing so, it is possible to absorb the change in the characteristics of the recording apparatus over time.
[0021]
As described above, it is possible to more accurately control the edge position of a recording mark in high-density recording using mark length recording.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. FIGS. 3 to 11 are diagrams showing the configuration of the elements in FIG. 1 in more detail. Further, in this configuration example, the amount of recording irradiation light pulse interval that needs to be considered to reduce the amount of edge fluctuation is affected by the amount of change in the edge position of one recording mark due to thermal interference. Are described before the corresponding edge timing, but the present invention is not limited to this.
[0024]
In FIG. 1, an optical disc 1 is rotated at a constant angular velocity by a spindle motor 2, and a laser beam for recording and reproduction is condensed by an optical pickup 3 on a recording film surface on the disc 1 by a focusing lens. The optical pickup 3 can move in the radial direction of the disc in accordance with the information recording position.
[0025]
A signal detected by a detector in the optical pickup 3 is amplified to a desired level by an amplifier 4 and then, by an equalizing circuit 5, in accordance with a rotational linear velocity of the optical disk at a laser light focusing position on a recording surface. Waveform equalization is performed. Thereafter, the signal is converted into a reproduced binary signal 7 which is a digital signal by the binary lower circuit 6. At the time of information reproduction, the reproduced binary signal 7 is separated into a data signal and a clock signal by a PLL (phase locked loop) circuit 8 and becomes reproduction data by a demodulation circuit 9.
[0026]
The above is the data reproduction signal processing system in the optical disk system employing the mark length recording method. In addition to the reproduction signal processing system, the recording characteristics are detected and the pulse interval adjustment amount during recording, and the recording power is calculated or updated in the recording characteristics measurement mode. There is a recording characteristic measurement system that operates in a recording condition check mode in which a recording condition such as a recording power and an environmental temperature at that time is checked using a recording condition check pattern recorded in a recording condition. This measurement system is operated by a controller that controls the entire optical disk system, and operates in a recording characteristic measurement mode and a recording condition check mode.
[0027]
There are two types of recording characteristic measurement modes: a pulse width adjustment table creation mode and a recording power search mode. In the recording characteristic measurement mode, first, the recording power search mode is executed, and thereafter, the pulse width adjustment table creation mode is continuously executed. In both modes, the recording power level is input from the controller to the laser driver 12 in the dedicated test pattern and the recording power search mode, and the laser in the optical pickup 3 is modulated according to these signals. The laser light is focused from the optical pickup 3 onto the optical disk surface, and a test signal is recorded. Then, using the reproduction signal of the recording mark corresponding to the test signal, a characteristic detection and change operation is performed in the recording characteristic measuring system.
[0028]
Hereinafter, the recording characteristic measuring system will be described.
[0029]
In the recording characteristic measurement mode and the recording condition check mode, the operation up to the binarization circuit 6 is the same as in normal data reproduction, and a reproduction binarization signal 7 for the test signal is obtained. The reproduced binary signal 7 is input to an edge timing detection circuit 13 and converted into a polarity inversion interval signal 14 which is a digital signal and a polarity inversion timing signal 15 which is a pulse signal. The edge timing detection circuit 13 performs the same operation in the pulse width adjustment table creation mode, the recording power search mode, and the recording condition check mode. The polarity inversion interval signal 14 is a digital value representing information on the length of the interval at which the polarity of the reproduced binary signal 7 changes, and the polarity inversion timing signal 15 changes the polarity of the reproduced binary signal 7. A pulse-like waveform is assigned to the timing.
[0030]
An output signal of the edge timing detection circuit 13 is input to a recording power setting determination circuit 16 and a pulse width setting determination circuit 17. The recording power setting determination circuit 16 operates in the recording power search mode and the recording condition check mode, and the pulse width setting determination circuit 17 operates in the pulse width adjustment table creation mode.
[0031]
The recording power setting determination circuit 16 determines the duty of the reproduction signal for each recording power setting value (strictly speaking, the average value of the difference between the rise-fall interval and the fall-rise interval of the binarized reproduction signal). Is calculated. In the recording power search mode, the recording power set value of the data is transmitted to the laser driver 12 simultaneously with the calculation result, and the laser driver 12 sets the recording power set value when the duty becomes 50%. In the recording condition check mode, it is checked whether or not the result is within a certain range, and the result is transmitted to the controller. The controller receives this signal and performs a procedure for entering the recording characteristic measurement mode when the signal is not within the predetermined range.
[0032]
The pulse width setting determination circuit 17 calculates the average value of the edge fluctuation amount for each pattern. In this circuit, data including pulse interval information of the test pattern for characteristic measurement is stored as reference data in the internal ROM in chronological order. Each time the polarity inversion interval signal 14 is received, it is converted into an edge variation using this reference data. Then, the accumulated value of the conversion result for each recording pattern is stored internally. An error in the detection signal due to a defect in the recording medium or the like is automatically detected in this circuit, and the occurrence of the error is notified to the controller. If no error has occurred, the average value of the edge fluctuation amount is calculated from the addition result stored at the end of the reception of the polarity inversion interval signal 14 and transmitted to the data conversion circuit 17.
[0033]
The data conversion circuit 17 operates in the pulse width adjustment table creation mode. The data conversion circuit 17 creates the pulse width adjustment table 19 based on the edge variation data transmitted from the determination circuit 17.
[0034]
As described above, the components from the edge timing detection circuit 13 to the data conversion circuit 17 detect the recording characteristics in the optical disk system, calculate and update the pulse interval adjustment amount during recording, and the recording power, and check the recording conditions at each recording. It is a circuit system.
[0035]
During normal information recording, the pulse width adjustment circuit 21 refers to the pulse width adjustment table 19 for the data that has been code-modulated by the modulation circuit 20 and adjusts the rising position and falling position of each recording pulse for each recording pulse. And correct it. Then, the recording pulse is input to the laser driver circuit 12, and the laser in the optical pickup 3 is modulated in accordance with the recording pulse and recorded on the disk 1.
[0036]
FIG. 2 shows an example of a characteristic detection test pattern waveform used in the recording characteristic measurement mode. FIG. 2A shows a waveform for the recording power search mode, in which the shortest recording pulse interval used for mark length recording is repeated. Then, the recording power set value is gradually changed every predetermined number of repetitions to increase the recording power. This recording power change range is set so as to include the signal amplitude at the optimum recording power as long as the use environment of the apparatus is within the guaranteed range.
[0037]
When recording general data, this waveform is also used for a recording condition check pattern that is usually recorded before data for each sector. However, at that time, the recording power setting value is not changed while it is already set. Further, for simplicity in this embodiment, the number of repetitions is also made to match the number of repetitions at each recording power at the time of recording power search.
[0038]
FIG. 2B is a waveform for the pulse width adjustment table creation mode, which is a waveform including a plurality of patterns having different combinations of three consecutive pulse intervals. In general, the greater the number of combinations, the more accurate a recording pulse adjustment table can be created. In the pulse width adjustment table creation mode, this pattern is repeatedly recorded, and an average value operation is performed on the calculated edge variation to improve the measurement accuracy.
[0039]
Here, the number of repetitions at each recording power of the characteristic measurement test pattern in the recording power search mode is 2 ＾ C.₂Times, the recording power increment is S₂The number of pulse intervals included in one cycle of the characteristic measurement test pattern in the pulse width adjustment table creation mode is represented by S₁, The number of times of repetition₁Explanation will be given as times.
[0040]
In FIG. 1, the optical disk 1, spindle motor 2, optical pickup 3, amplifier 4, binarization circuit 6, PLL circuit 8, and demodulation circuit 9 may have the configuration and function used in the conventional optical disk device. , And a detailed description thereof will be omitted.
[0041]
Hereinafter, other components will be described.
[0042]
FIG. 3 is a diagram showing one configuration example of the equalization circuit 5, and FIG. 4 is a diagram for explaining the operation thereof. Here, an equalizing circuit when the number of taps is three will be described. 3, the data signal amplified by the amplifier 4 is converted into a low impedance signal by a voltage follower 301 by an operational amplifier, and is input to a delay element 302. The resistors 303 and 304 before and after the resistor 303 are for matching with the characteristic impedance of the delay element 302.
[0043]
Of the signals delayed by the delay element 302, the center tap signal, which is an output signal from the center tap position, is directly input to the addition circuit 305 including an amplifier. One of the outputs from the tap positions closer to the delay line input side than the center tap position is selected by the multiplexer 306 and input to the addition / inversion amplifier circuit 307. Similarly, one of the outputs from the tap positions farther from the delay line input side than the center tap position is selected by the multiplexer 308 and input to the addition / inversion amplifier circuit 307. The amplification factor in the addition / inversion amplifier circuit 307 is variable by switching the value of the feedback resistor 309 by the multiplexer 310. The output signal of the addition / inversion amplification circuit 307 is input to the addition circuit 305, and is input to the binarization circuit 6 as the output signal of the equalization circuit 5.
[0044]
Next, the operation of the equalization circuit 5 of FIG. 3 will be described with reference to FIG. In FIG. 4, f (t) is a waveform corresponding to the data signal input to the equalizer circuit 5 shown in FIG. 3, and here represents a reproduced signal for an isolated recording mark for easy understanding. Generally, an optical disk has a finite light spot size, which cannot be ignored compared to the size of a recording mark. Therefore, for example, even if the center of the light spot is on the recording film surface at a position where there is no recording mark, the end of the light spot may cover a part of the adjacent recording mark, and the end of the light spot may Appears as an interference component of the waveform. This is the intersymbol interference caused by the low optical frequency band. In addition, the characteristics of the reproduction signal detection system are also reduced on the high frequency side, causing intersymbol interference.
[0045]
In the inter-symbol interference, since the rise and fall of the signal amplitude at the sampling point t = NT are slow in the data signal f (t), the components thereof are in the vicinity of the sampling points t = (N−1) T and (N + 1). ) Even in T, it appears as a signal amplitude in the reproduced signal. In a general reproduced waveform in which a plurality of recording marks exist and such waveforms overlap, this intersymbol interference causes the amplitude degradation of the reproduced signal, and the signal determination is apt to be erroneous due to the influence of superimposed noise. I have.
[0046]
The equalizing circuit 5 of FIG. 3 has an effect of compensating for such a deterioration in characteristics on the high frequency side and reducing the influence of intersymbol interference. In FIG. 4A, when the center tap signal is f (t), the output signals of the delay element 302 are signals f (t−τ) and f (t + τ) obtained by delaying f (t) by ± τ, respectively. Hit. Output signals of these delay elements 302 are subjected to signal processing in an addition / inversion amplification circuit 307 and an addition circuit 305,
[0047]
f (t) −K {f (t−τ) + f (t + τ)} (Equation 1)
As a result, an output signal as shown in FIG. 4B is obtained. This signal waveform is steeper than the waveform of f (t), and the influence of the signal amplitude at the sampling point t = NT is suppressed small at the sampling points t = (N−1) T and (N + 1) T in the vicinity. Thus, the effect of intersymbol interference is reduced.
[0048]
The parameters that determine the characteristics of the equalization circuit 5 shown in FIG. 3 include the delay time τ and the amplification factor K. The delay time τ can be changed by multiplexers 306 and 308, and the amplification factor K can be changed by multiplexer 310. In the case of an optical disk, the optical frequency characteristics differ due to the difference in linear velocity between the inner and outer peripheral sides of the disk. That is, for example, when the recording linear density is the same on the inner and outer circumferences of the disk and the recording mark shape is the same, the spatial frequency characteristics are the same, but the linear velocity is different on the inner and outer sides, so The frequency characteristics are different. In many actual cases, the recording linear density and the recording mark shape also differ between the inner and outer circumferences of the disk, so that the frequency characteristics differ spatially and temporally. Accordingly, since the optimum characteristics of the equalizing circuit 5 also change between the inner and outer circumferences of the disk, the delay amount τ and the amplification factor K are set with respect to the disk radial position based on the track address value on the disk. By this operation, it is possible to always realize a nearly optimal equalization condition regardless of the radius of the disk.
[0049]
As described above, the case where the number of taps of the equalizing circuit 5 is three has been described. However, it is necessary to design the number so that the influence can be sufficiently reduced from the range of the intersymbol interference in the waveform of f (t). is there.
[0050]
FIG. 5 is a diagram showing one configuration example of the edge timing detection circuit 13 in FIG. 1, and FIG. 6 is a diagram for explaining the operation thereof.
[0051]
The reproduced binary signal 7, which is the output of the binary circuit 6, is input to the impulse signal generation circuit 501. The impulse signal generation circuit 501 outputs an impulse-like signal waveform at each timing when the polarity of the input signal changes, and this output signal is input to the determination circuit 16 and the A / D converter 502 as the polarity inversion timing signal 15. .
[0052]
On the other hand, the reproduced binary signal 7 is also input to an integration circuit 503 composed of an amplifier. The "H" level of the reproduced binary signal 7 is set to V_H, “L” level to V_L-(V_H+ V_L) / 2 are also input. Then, an integration signal 505 of the difference between the reproduction binary signal 7 and the integration reference signal 504 is detected from the integration circuit 503 and input to the A / D converter 502.
[0053]
A characteristic measurement mode signal 506 and a recording condition check mode signal 507, which are signals from the controller, are input to an OR circuit 508, and the result is input to a flip-flop 509. The polarity determination timing signal 15 is also input to the flip-flop 509 as a clock signal. The output of the flip-flop 509 is input to the switching terminal of the analog switch 510 as a signal representing the interval measurement period upon detecting the first rise of the reproduced binary signal 7 after entering the recording characteristic measurement mode or the recording condition check mode. You. Except at the time of characteristic measurement, the analog switch 510 is turned on by this signal, and the output of the integrating circuit 503 is initialized to zero. Then, when the characteristic measurement starts, the analog switch 510 is turned off, and the operation of the integration circuit 503 is started.
[0054]
The A / D converter 502 converts the integration signal 505, which is an input signal, into a digital signal using the polarity inversion timing signal 15 as a timing clock for performing a digital conversion operation. The conversion result is output as the polarity inversion interval signal 14 and input to the determination circuits 16 and 17. The conversion accuracy of the A / D converter 502, that is, the polarity inversion interval signal 14 has a sufficient accuracy that its value is used as a pulse interval adjustment amount, and a quantization accuracy and each interval so that overflow does not occur. Has the number of digits (the number of bits) for representing the value of.
[0055]
Next, the operation of the edge timing detection circuit 13 of FIG. 5 will be described with reference to FIG. The reproduction binarization signal 7 is a digital signal output from the binarization circuit 6, and has a level of "H" or "L" depending on whether or not there is a recording mark at the irradiation light spot position on the recording film surface. . The reproduced binarized signal 7 passes through an impulse signal generation circuit 501 and becomes a polarity inversion timing signal 15 to which an impulse waveform is assigned at a timing when its polarity changes, and is used by the determination circuits 16 and 17 and an A / D converter 502. It is used to generate a trigger signal and a signal indicating the start and end timings of the operation of the integration circuit 503.
[0056]
An output signal of the characteristic measurement mode signal 506 and the recording condition check mode signal that have passed through the OR circuit 508 is a digital signal representing the operation state of this circuit, and is “H” when this circuit is in operation state, and “H” otherwise. L "level. The flip-flop 507 uses the polarity inversion timing signal 15 to obtain an accurate characteristic measurement period, and operates the period integration circuit 503 for that period.
[0057]
In the integration circuit 503, the pulse interval of the reproduced binary signal 7 is calculated and output. In general, when the input signal is X (t), the integrating circuit 503 generates an output signal Y (t) as
[0058]
Y (t) = ∫₀ ^tX (τ) dτ + Y (0) (Equation 2)
Is obtained. Let the pulse interval of the reproduced binary signal 7 be P₁, P₂, P₃, ……, P_N, The output signal level V of the integrating circuit 503₀  At the time when the i-th pulse of the polarity inversion timing signal 15 rises, if i is an even number,
[0059]
V₀= A (-P₁+ P₂-P₃+ ...- P_i-1)… (Equation 3)
If i is odd,
[0060]
V₀= A (-P₁+ P₂-P₃+ …… + P_i-1)… (Equation 4)
Becomes Here, A in the above equation is a constant determined by the amplification factor of the integration circuit 503. That is, the output signal level at this point represents the result of integrating the pulse interval when the "H" level is represented by a negative value and the "L" level is represented by a positive value for the pulse interval of the reproduced binary signal 7. ing. Therefore, the A / D converter 502 converts the integrated signal level at that time into a digital value using the polarity determination timing signal 15, and inputs the conversion result to the determination circuit 16 as the polarity inversion interval signal 14.
[0061]
It is necessary to design the quantization accuracy of the A / D converter 502 so as to obtain sufficient accuracy for detecting the edge fluctuation amount of the reproduced binary signal. Further, since the integration signal 505 and the polarity determination interval signal 14 represent the cumulative number of the reproduced binary signal 7, these values are always in a range that can be used by the integration circuit 503 and are converted by the A / D converter 502. It is desirable to devise a characteristic measurement test pattern so as to fall within the range as possible.
[0062]
FIG. 7 shows an example of the configuration of the recording power setting determination circuit 16 in FIG. The circuit receives a characteristic measurement mode signal 506, a power / pulse width signal 701, and a recording condition check mode signal 507 from a controller. The characteristic measurement mode signal 506 indicates “H” level in the characteristic measurement mode, and “L” level in other cases. The power / pulse width signal 701 indicates “H” level in the recording power search mode and “L” level in the pulse width adjustment table creation mode. The recording condition check mode signal 507 is at the “H” level in the recording condition check mode, and is at the “L” level otherwise. Therefore, the result of these signals passing through the AND circuit 702 and the OR circuit 703 becomes "H" level in the recording power search mode and the recording condition check mode. At that time, these circuits are constituted by the counter circuits 704, 705 and flip-flops. The clear level of the latch circuit 706 and the flip-flops 707 and 708 is released, and the recording power setting determination circuit 16 operates.
[0063]
Each time the data of the polarity reversal interval signal 14 from the edge timing detection circuit 13 is updated, the addition circuit 709 calculates the sum of the data and the output data of the latch circuit 706. Then, the polarity inversion timing signal 15 sent at the same timing as the data update of the polarity inversion interval signal 14 passes through the delay element 710 and is input as a clock signal to the latch circuit 706 at the timing when the result of the addition circuit 709 is obtained. Is done. The latch circuit 706 latches the addition result at that time, and holds the result as an output signal until the next clock is input. Therefore, this output signal indicates the accumulated result of the polarity inversion interval signal 14 up to that point. The polarity inversion interval signal 14 indicates that the length of the "L" level of the reproduced binary signal 7 is positive and the length of the "H" level is negative. It represents the cumulative value of the difference between the length of the “H” level and the length of the “L” level.
[0064]
The output of the delay element 710 is also input to the counter circuit 704 as a clock signal. Then, the count number is input to the decoder circuit 711, and the number of repetitions (more precisely, the number of pulse intervals) for each power setting value of the test pattern₁, The output of the decoder circuit 711 becomes "H" level. This signal passes through a NOT circuit 712 and an AND circuit 713 and is input to a latch circuit 706 to clear its contents to zero. The output of the AND circuit 713 is also input to the counter circuit 705 and the flip-flops 707 and 708 as a clock signal. The output value of the counter circuit 705 is counted up by one to indicate the next recording power set value. In the flip-flops 707 and 708, the operation results of the addition circuit 709 and the subtraction circuits 714 and 715 with the output data immediately before the latch circuit 706 is cleared to zero are latched.
[0065]
The MSB (Most Significant Bit) signal is input to the flip-flop 707 among the output signals of the adder circuit 709. This signal indicates the sign of the addition result of the addition circuit 709, and is "L" when positive and "H" when negative. That is, this signal is “L” when the “L” level of the reproduced binary signal is longer than the “H” level from the time when the recording power set value is switched to the present time, and the “H” level is higher than the “L” level. When it is long, it is "H". Therefore, when the data latched by the flip-flop 707 is "L" by the clock signal which is the output signal of the AND circuit 713, the "L" level of the reproduced binary signal is longer than the "H" level, and This means that the recording power was low. Conversely, when it is at the "H" level, it means that the recording power at that time was high. Therefore, when the recording characteristic measurement test pattern recorded with the recording power gradually increased is reproduced, this data is switched from "L" to "H" in the middle, and the output value of the counter circuit 705 at that time is set as the optimum recording power. Set.
[0066]
The output signal of the addition circuit is also input to the subtraction circuits 714 and 715. In the subtraction circuits 714 and 715, the upper limit and the lower limit of the allowable range in the recording condition check mode are set as the other input signals. Therefore, by inputting only the MSB signal of both subtraction results to the AND circuit 716, an "L" level is output as an output signal when the value is out of the allowable range in the recording condition check mode. This signal is input to the flip-flop, latched as a determination result when a clock signal output from the AND circuit is input, that is, when the recording condition check pattern is completed, and sent to the controller side. When the controller detects that this signal is at the "L" level, a procedure for entering the recording characteristic measurement mode is performed.
[0067]
FIG. 8 shows an example of the configuration of the pulse width setting determination circuit 17 in FIG. This circuit receives a characteristic measurement mode signal 506 and a power / pulse width signal 701 from a controller. The result of these signals passing through the NOT circuit 801 and the AND circuit 802 becomes “H” level in the pulse width adjustment table creation mode. At that time, the counter circuits 803 and 804, the M−1 stage shift registers 805 to 810, The clear level of the latch circuit 811 including flip-flops and the flip-flops 812 and 813 is released, and the recording power setting determination circuit 17 operates.
[0068]
The polarity inversion timing signal 15 from the edge timing detection circuit 13 is an input signal of the counter circuit 803. Every time a pulse signal is input, the output data of the counter circuit 803 increases by one and the value is stored in the ROM circuit 814. Input as an address signal. At that time, the data at the corresponding address is read from the ROM circuit 814 and input to the adding circuit 815. The polarity inversion interval signal 14 from the edge timing detection circuit 13 updated at the same time as the pulse signal of the polarity inversion timing signal 15 is also input to the addition circuit 815, and the addition result is output.
[0069]
In the ROM circuit 803, data indicating cumulative values up to each polarity inversion position are stored in order from address 0, with the length of the “H” level of the characteristic measurement test pattern being positive and the length of the “L” level being negative. ing. That is, the pulse interval of the characteristic measurement test pattern is T₁, T₂, T₃, ……, T_N, The data R at the address i (i ≦ M) of the ROM circuit 803_iIs when i is even,
[0070]
R_i= A (T₁−T₂+ T₃+ …… + T_i-1)… (Equation 5)
If i is odd,
[0071]
R_i= A (T₁−T₂+ T₃+ ...- T_i-1)… (Equation 6)
Becomes The quantization accuracy of the pulse interval is equal to the quantization accuracy when the pulse interval of the reproduced binary signal 7 is converted into the polarity inversion interval signal 14. That is, A in the above equation is equal to a constant A determined by the amplification factor of the integration circuit 503. Therefore, for example, the pulse intervals during recording and during reproduction are equal, that is, P₁= T₁, P₂= T₂, …… P_N= T_N, The data R at the address j stored in the ROM circuit 803_jAnd the data V of the j-th polarity inversion interval input to the pulse width setting determination circuit 17₀Are different in sign and have the same absolute value. That is, the k-th output of the adder circuit 815 is defined as the recording pulse and the leading pulse edge position in the pulse of the reproduced binary signal, and the edge position of the k-th recording pulse and the k-th reproduced binary signal. , The amount of deviation from the position of the pulse edge, that is, the amount of edge fluctuation.
[0072]
The output signal of the addition circuit 815 is input to the addition circuit 816, and is added to the outputs of the shift registers 805 to 810. The result is input to the latch circuit 811 and then to the shift registers 805 to 810. The shift registers 805 to 810 and the latch circuit 811 constitute a ring-shaped storage circuit (M stages), and the addition circuit 816 calculates and stores the accumulated value of the edge variation amount every M pieces. Since the number of pulse intervals in one cycle of the test pattern in the pulse width adjustment table creation mode is M, an accumulated value is calculated for each of the same patterns. A polarity inversion timing signal is input to the clock signals of the shift registers 805 to 810, and a signal obtained by passing the polarity inversion timing signal through the delay element 817 is input to the clock signal of the latch circuit 811. Perform the latch.
[0073]
When an overflow occurs in the operation result of the addition circuits 815 and 816, the level of each carry signal becomes “H”. This occurs when a location where the recording characteristic measurement pattern could not be recorded normally due to a defect or the like of the optical disc 1 is detected. This result passes through the OR circuit 818 and generates an "H" level as a measurement error when an overflow occurs on one side. Then, the output signal of the delay element 817 is input to the flip-flop 812 as a clock signal, the data is latched at the timing when the data is determined, and the data is transmitted to the controller. When an error occurs, the characteristic measurement is stopped.
[0074]
The output of the counter circuit 803 is also input to the decoder circuit 819. The decoder circuit 819 outputs an “H” level when the output value of the counter circuit 803 becomes M−1. The signal is input as a clear signal of the counter circuit 803 through the NOT circuit 820 and the AND circuit 821, and the counter circuit 803 is initialized each time the characteristic measurement test pattern has been reproduced for one cycle.
[0075]
The output signal of the decoder circuit 819 is also input to the counter circuit 804, and counts the number of cycles of the reproduced characteristic measurement test pattern. The output of the counter circuit 804 is input to the decoder circuit 822, and the characteristic measurement test pattern is set to 2 ° C.₂"H" level is output from the decoder circuit 822 at the start of the -1 period, and the start of data transmission is transmitted to the data conversion circuit 18 as the conversion start signal 823. Also, when data transmission to the data transmission circuit 18 is started, the data conversion circuit 18 simultaneously starts updating the pulse width adjustment table 19, and even if an error occurs at this point, the characteristic measurement cannot be stopped. At this time, the signal masks the output of the decoder circuit 822 by the NOT circuit 824 and the AND circuit 825. However, at that time, the flip-flop 813 and the selector circuits 826 to 831 perform control so as to output the accumulated value up to the previous time, instead of outputting the output signal of the latch circuit 811 including the error. This output signal is sent to the data conversion circuit 18 as an edge shift signal 832.
[0076]
As the transfer timing, a signal whose output is delayed from the output of the delay element 817 as a timing signal 833 in which the output data of the selector circuits 826 to 831 is determined is further generated through the delay element 834 and transmitted to the data conversion circuit 18. .
[0077]
FIG. 9 is a configuration example of the data conversion circuit 18 and the pulse width adjustment table 19 in FIG. The conversion start signal 823, the edge shift signal 832, and the timing signal 833 are input from the pulse width setting determination circuit 17 to this circuit. Each time a pulse signal is input by the timing signal 833, the output data of the counter circuit 901 increases by one, and the value is input to the ROM circuits 902 to 904 as an address signal. The output signal of the counter circuit 901 is input to the decode circuit 905, and the output of the decode circuit 905 becomes "H" level only when its value is 1, that is, when the pulse waveform input of the first timing signal is received. This signal is input to the clear terminal of the pulse width adjustment table 19, and the contents of the table are cleared to zero when the output of the decoder circuit 905 becomes "H" level, that is, when the table update starts.
[0078]
The ROM circuit 902 stores the pulse interval T of the characteristic measurement test pattern.₁, T₂, T₃, ……, T_NAre sequentially stored from the head address + 2 (address 2).
[0079]
Also, the ROM circuit 903 has T₁, T₂, T₃, ……, T_NAre sequentially stored from the start address + 1 (address 1).₁, T₂, T₃, ……, T_NAre sequentially stored from the head address (address 0). Data 0 is stored in the addresses 0 and 1 of the ROM circuit 902 and the address 0 of the ROM circuit 903 (actually, any value that cannot be obtained at the recording pulse interval may be used).
[0080]
The outputs of the ROM circuits 902 to 903 are input as address signals to the pulse width adjustment table 19 through the gate circuits 906 to 907. On the other hand, the output of the ROM circuit 904 is input as a data signal to the pulse width adjustment table 19 through the gate circuit 908. The output signal of the same ROM circuit 904 is input to the addition / subtraction circuit 909, and the addition / subtraction is performed with the edge shift signal 832 from the pulse width setting determination circuit 17. The LSB (Least Significant Bit) of the output signal of the counter circuit 901 is input to the addition / subtraction circuit 909 as a selector signal. This is because the edge shift direction when the value of the edge shift signal 832 is positive is alternately changed, so that the addition and subtraction are switched for each one to make the edge shift direction constant. The output of the addition / subtraction circuit 909 is input as an address signal to the pulse width adjustment table 19 through the gate circuit 910. Gate circuits 906 to 908 and 910 send signals from ROM circuits 902 to 904 and addition / subtraction circuit 909 to pulse width adjustment table 19 as these output signals while edge shift signal 832 is being transmitted. . In addition, a timing signal 833 is input to the chip select terminals of both pulse width adjustment tables 19 through NOT circuits 911 and AND circuits 912 and 913 in order to distribute the data for the front edge and the data for the rear edge of the pulse width adjustment table 19. ing.
[0081]
As described above, when the i-th data is input from the edge shift signal 832, the edge fluctuation amount is set to e._i(Where the spot traveling direction is positive), the address (T_1-2, T_i-1, T_i+ E_i) To data T_iIs performed. Therefore, when data is actually recorded, for example, T_1-2, T_i-1, T_i+ E_iWhen a pattern such as “T” appears, the address (T_1-2, T_i-1, T_i+ E_i) With reference to the data T stored at that position._iTo T_i+ E_iAnd use it as the recording pulse interval. As a result, the recording mark becomes e_iAnd the desired pulse interval T_i+ E_iThus, the effect of the edge shift can be canceled.
[0082]
However, it is generally difficult to prepare the pulse interval of the test pattern for characteristic measurement in a number including all cases. In actuality, in order to complete the empty area of the pulse width adjustment table 19, the edge shift is performed. After all the signals 832 have been received, the data interpolation circuit 914 is operated. In this circuit, data where the content of the pulse width adjustment table 19 is 0 is found in the vicinity thereof as non-zero data, and interpolation calculation is performed. When the calculation is completed, the data interpolation circuit 914 notifies the controller that the characteristic measurement / pulse width adjustment table updating operation has been completed, and the recording characteristic measurement mode ends.
[0083]
FIG. 10 shows a configuration example of the pulse width adjustment circuit 21 and the pulse width adjustment table 19 in FIG. The recording data, which is the output signal of the modulation circuit 20, is obtained by multiplying the number of codes "0" between the codes "1" and "1" after code modulation by a constant, and the quantization accuracy is determined by a pulse width adjustment table. 19, that is, the conversion accuracy of the A / D converter 502, and input to the latch circuits 1001 and 1002. In the recording data, clock signals are alternately input to the latch circuits 1001 and 1002, and the data is alternately latched and output by both. This output signal is added to the immediately preceding edge position adjustment amount (positive in the direction opposite to the spot traveling direction) in the adding circuits 1003 and 1004. By this operation, a longer pulse interval is taken here by the previous edge position adjustment, so that the edge position comes to the same position as before the conversion.
[0084]
The pulse interval after adjustment is obtained by referring to the pulse width adjustment table 19 using the output data of the adders 1003 and 1004. When referring to the pulse width adjustment table 19, the previous pulse interval (after adjustment) from the latch circuits 1005 and 1006 and the last two pulse intervals (after adjustment) from the latch circuits 1006 and 1005 are simultaneously input and after the adjustment. Used for pulse interval determination. This output signal is latched and held by latch circuits 1007 and 1008.
[0085]
The output signal is supplied to the down counter circuits 1010 and 1011 together with the clock signal 1009 having one cycle of the quantization accuracy of the recording data output from the modulation circuit 20 to realize the recording pulse width. Is entered as Since the time from when the initial value is set until the output value becomes 0 is the recording pulse interval, the OR circuits 1012 and 1013 detect that the output values of the down counter circuits 1010 and 1011 become 0. A NAND circuit 1014 and a flip-flop 1015 combine both outputs to generate a pulse, which is input to the laser driver circuit 12 as a pulse signal 1016.
[0086]
The output of the OR circuit is input to the latch circuits 1001, 1002, 1005, and 1006 as a clock signal, and is used as a timing for latching the next data. This signal is input as a clock signal to the latch circuits 1007 and 1008 through the delay elements 1017 and 1018, and latches at the timing when the data is determined. The difference between the signal before the table reference and the signal after the table reference is the adjustment amount of the edge position. This value is calculated by the subtraction circuits 1019 and 1020 and input to the addition circuits 1004 and 1003.
[0087]
With the above circuit, the pulse interval of the recording data is sequentially adjusted according to the pattern by referring to the pulse width adjustment table 19.
[0088]
FIG. 11 shows an example of the configuration of the laser driver circuit 12 in FIG. In this figure, a circuit for driving the semiconductor laser 1101 is a current switch including NPN transistors 1102 and 1103.
[0089]
The pulse signal 1016 is input to the selector circuit 1104. This circuit has a terminal for selecting an input signal, a signal from a controller is input, and an output signal is selected. When recording normal data, the pulse signal is selected as the output signal. Then, only in the recording characteristic measurement mode, a pulse of a pulse width adjustment test pattern or a recording power search test pattern from the controller, which is another input signal, is selected as a signal output signal.
[0090]
This output signal is input to an ECL (emitter coupled logic) AND circuit 1105. The non-inverted signal and the inverted signal of this circuit are level-shifted by zener diodes 1106 and 1107, and then input to base terminals of transistors 1102 and 1103, which are components of a current switch. In this current switch, when the transistor 1103 is turned on, the current is superimposed by the current value set by the transistor 1108. A current source for supplying a current sufficient for the semiconductor laser of the transistor 1109 to emit light at the reproduction level is configured. On the other hand, the transistor circuit 1108 sets a current to be superimposed during recording, applies the output voltage of the D / A converter 1110 to the base terminal of the transistor 1108, and sets a voltage between the emitter terminal of the transistor 1108 and the voltage −V. A current having a value obtained by dividing the potential difference by the value of the resistor 1111 flows. The operational amplifier 1112 forms a voltage follower, and suppresses variation in the potential difference between the base and the emitter of the transistor 1108.
[0091]
The recording power is determined by the input data of the D / A converter 1110. This value is set to the value set by the controller by the selector circuits 1113 to 1116 or the value of the output data of the flip-flop 1117. The signal for making this selection is input from the controller. During normal data recording, the values of the output data of the flip-flop 1117 are selected by the selector circuits 1112 to 1115, and the value set by the controller is selected only when recording the characteristic measurement test pattern in the recording power search mode.
[0092]
At the time of recording the test pattern for characteristic measurement, first, a set value 1 is set in the D / A converter from the controller, and the test pattern is set to 2 ＾ C₁The set value is increased by one each time the recording is repeated, and the recording power is gradually increased. Then, the recording mark is reproduced, and the edge timing detection circuit 13 and the determination circuit 16 for recording power setting determine which recording power is optimal. By storing the number in the flip-flop 1117 and setting it in the D / A converter, the optimum setting of the recording power is realized.
[0093]
The optimum recording power number is determined by the characteristic measurement mode signal 506, power / pulse width signal 701, and recording so that the flip-flop 1116 latches when the recording power is determined in the recording power search mode by the NAND circuit 1118 and the OR circuit 1119. The output of the flip-flop 707 in the power setting determination circuit 16 is used as an input signal.
[0094]
The above is the description of the operation of each component according to the embodiment of the present invention. By using this recording pulse edge adjustment amount calculation method, it is possible to eliminate a change in edge position in a reproduced waveform due to thermal interference, which occurs due to a different recording pattern in the same recording pulse.
[0095]
In the above embodiment, the case where the recording linear velocity is constant has been described. However, since the rotation speed of many optical disks is constant, the linear velocity actually varies depending on the recording radius, and the recording characteristics also differ. In the case of an optical disk, considering that random access is required, it is necessary to perform a detection operation by recording a characteristic measurement test pattern at a plurality of positions on the disk surface having different linear velocities when recording characteristics are measured. A plurality of pulse width adjustment tables 19 are prepared.
[0096]
The area used for this measurement is a plurality of locations including the inner circumference side, the outer circumference side, and between them. The area may be specially provided or a general data recording area. In the latter case, if recording data already exists in the area, use another free area or transfer the information written in the area to use that area to another memory such as a memory in the temporary controller. The process of evacuating to the place is performed.
[0097]
The pulse width setting determination circuit 17 calculates the average value of the edge fluctuation amount for each test pattern (not for each pulse interval but for each combination of a plurality of continuous pulse intervals). This depends on the recording pulse pattern near the laser beam pulse edge at the time of recording corresponding to the reproduced waveform edge due to thermal interference in addition to the combination of the recording device and the recording medium, and the linear velocity. Because it is.
[0098]
Generally, the edge position of the reproduced waveform corresponding to the laser pulse edge at the time of a certain recording has a large influence from the pattern recorded immediately before that. In contrast, the effect of the subsequent recording pulse pattern is small, and if the thermal conductivity of the recording medium is extremely large, or if the linear velocity during recording is excessively small and the effect of thermal interference is extremely large, the edge of the recording signal This effect is negligible except when the interval is extremely short and when the domain wall energy of the recording medium at the time of forming the recording mark is large.
[0099]
The range of the recording pulse pattern on the front side having the above-mentioned influence can be mainly defined by its length. This depends on the linear velocity, and the range becomes wider toward the inner circumference when considered on the time axis. However, in an actual system, the range may be adjusted to the inner circumference where this condition is poor, or the range may be switched according to the linear velocity. In addition, since this range is generally difficult to handle as the length of time, it is somewhat redundant, but it is handled by the number of recording patterns, and the amount is the worst condition, that is, when the pattern of the minimum polarity inversion interval is continuous. It is better to determine the number of influences. Therefore, in this embodiment, an example in which this range is set to three recording patterns has been described.
[0100]
This recording characteristic measurement operation is performed when the apparatus is turned on, when the disk is replaced, and when an error (that is, the recording condition deviates from the set value) is detected at the time of recording condition check performed at each data recording. To be designed. Further, it is desirable to design so as to perform this operation periodically when there is no recording operation for a while.
[0101]
The present invention provides a description of any information recording method that is rewritable and whose principle is a recording method using heat, and a description of a basic method relating to control of recording conditions such as recording power and recording pulse interval applicable to a recording medium. It is. A recording method and a recording medium which have a particularly high heat diffusion effect and are sensitive to recording conditions, that is, a recording characteristic which appears as a difference in recording characteristics due to a slight change in recording power, environmental temperature, configuration of a recording medium, and characteristics of a recording apparatus. In this case, it is effective in securing the reliability of the recording data.
[0102]
For example, the present invention is particularly useful for a magneto-optical disk, a magneto-optical disk capable of overwriting using exchange coupling force, an optical disk utilizing phase change capable of overwriting, and the like.
[0103]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the fluctuation | variation regarding the edge position of a reproduction signal by heat interference can be eliminated. In addition, in order to always measure and update the recording characteristics whenever the combination of each recording medium and the recording device changes, and with the passage of time, optimal recording conditions are always realized. In addition, higher-density recording can be easily realized without strict adjustment at the time of manufacturing, and the reliability of recorded data is greatly improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.
FIG. 2 is a diagram showing an example of a characteristic detection test pattern waveform used in a recording characteristic measurement mode.
FIG. 3 is a diagram showing one configuration example of an equalization circuit.
FIG. 4 is an explanatory diagram of an operation of the equalization circuit.
FIG. 5 is a diagram showing one configuration example of an edge timing detection circuit.
FIG. 6 is an explanatory diagram of an operation of the edge timing detection circuit.
FIG. 7 is a diagram showing one configuration example of a recording power setting determination circuit.
FIG. 8 is a diagram showing one configuration example of a pulse width setting determination circuit.
FIG. 9 is a diagram showing one configuration example of a data conversion circuit and a pulse width adjustment table.
FIG. 10 is a diagram illustrating a configuration example of a pulse width adjustment circuit and a pulse width adjustment table.
FIG. 11 is a diagram illustrating a configuration example of a laser driver circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Spindle motor, 3 ... Optical pickup, 4 ... Amplifier, 5 ... Equalization circuit, 6 ... Binarization circuit, 7 ... Reproduction binarization signal, 8 ... PLL (phase lock loop) circuit , 9 demodulation circuit, 12 laser driver, 13 edge timing detection circuit, 14 polarity reversal interval signal, 15 polarity reversal timing signal, 16 determination circuit for setting recording power, 17 determination circuit for setting pulse width, 18 data conversion circuit, 19 pulse width adjustment table, 20 modulation circuit, 21 pulse width adjustment circuit 21, 301 voltage follower, 302 delay element, 305 addition circuit, 306 multiplexer, 307 addition addition and inversion Amplifying circuit, 308 multiplexer, 501 impulse signal generating circuit 501, 502 A / D converter, 503 integrating circuit, 504 integrating Reference signal, 505: integration signal, 506: characteristic measurement mode signal, 507: recording condition check mode signal, 509: flip-flop, 510: analog switch, 701: power / pulse width signal, 704, 705: counter circuit, 706 ... Latch circuit, 707, 708 flip-flop, 709 addition circuit, 710 delay element, 711 decoder circuit, 714, 715 subtraction circuit, 803, 804 counter circuit, 805-810 shift register, 811 latch circuit ..., 812, 813 ... flip-flop, 814 ... ROM circuit, 815, 816 ... addition circuit, 817 ... delay element, 819, 822 ... decoder circuit, 823 ... conversion start signal, 826-831 ... selector circuit, 832 ... edge shift signal 833 ... timing signal, 834 ... delay 901: counter circuit, 902 to 904: ROM circuit, 905: decode circuit, 906 to 908, 910: gate circuit, 909: addition / subtraction circuit, 914: data interpolation circuit, 1001, 1002, 1003 to 1008 ... Latch circuit, 1003, 1004 addition circuit, 1009 clock signal, 1010, 1011 down counter circuit, 1015 flip-flop, 1016 pulse signal, 1017, 1018 delay element, 1019, 1020 subtraction circuit, 1101 semiconductor Laser, 1102, 1103, 1108, 1109: transistor, 1104: selector circuit, 1106, 1107: zener diode, 1110: D / A converter, 1112: operational amplifier, 1113 to 1116: selector circuit, 1117: flip-flop.

Claims (2)

An information recording method of irradiating a laser beam in a pulse shape on a recording medium and recording information by a mark length recording method,
Create a correspondence table of the edge fluctuation amount depending on the recording pulse pattern near the laser light pulse edge during recording,
An information recording method, wherein information is recorded by controlling an edge position for each recording pulse pattern based on the correspondence table. An information recording method of irradiating a laser beam in a pulse shape on a recording medium and recording information by a mark length recording method,
Recording a first test pattern having n consecutive pulses (n is an integer) having different pulse intervals, each of which has a plurality of patterns in which the combination of the pulses is different;
The combination is classified for each different pattern to calculate the average value of the edge fluctuation amount, to calculate the recording pulse interval adjustment amount,
An information recording method, wherein the information is recorded by controlling the recording pulse interval adjustment amount for each of the patterns having the different combination based on the correspondence between the pattern having the different combination and the recording pulse interval adjustment amount. .

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