JPH0644567A - Optical memory device and its recording and reproducing control method - Google Patents

Abstract

PURPOSE:To stably read and write data by controlling a shortest pit and a shortest gap pulse width with a recording pulse width control means and controlling other pulse widths with another recording pulse width control means. CONSTITUTION:Reproduced data 10 and recorded pulses are inputted to terminals 9 and 7, respectively. A recording pulse width control means 2 controls the pulse widths of a shortest pit and a shortest gap among recording pulses and a recording pulse width control means 3 increases/decreases total pulse widths uniformly and performs the control. A recording power control means 4 controls the power at the time of recording, a semiconductor laser driving circuit 5 drives a semiconductor laser 6 by the outputs of the means 3 and 4. A pulse width detecting means 1 detects the pit sections of the reproduced data 10 or the pulse width between pit sections.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling recording / reproducing means of an optical memory device.

[0002]

2. Description of the Related Art A conventional optical memory device is disclosed in JP-A-2-627.
As shown by 26, recording is performed using a recording pulse width correction circuit that delays the rising edge of the recording pulse and accelerates the falling edge. The correction amount is adjusted by detecting the reproduction pulse width.

[0003]

However, in the above-mentioned prior art, the control of the recording pulse width is performed uniformly for all pulses. Due to variations in the characteristics of the optical system, the correction state of the reproduction system deviates from the optimum state, and as a result, the pulse width when reproducing the shortest pit or shortest gap deviates from the ideal value, and the margin of the reproduction system disappears. In particular, when the density is increased, this effect becomes remarkable, and there is a problem that data cannot be reproduced correctly.

Therefore, the present invention solves such a problem, and an object of the present invention is to provide an optical memory device capable of always maintaining an optimum recording / reproducing state.

[0005]

An optical memory device and a recording pulse control method therefor according to the present invention include: (1) Recording is performed by a pit edge method in which information is provided at both edge portions of a pit by using a semiconductor laser or the like as a light source. In an optical memory device for reproducing data by the second-order differential method, a) pulse width detecting means for detecting a pulse width of a pit portion or a gap portion between the pits from the reproduced data, and b) from the pulse width detecting means. Recording pulse width control means 1 for controlling the recording pulse width of the shortest pit and the shortest gap by the output of c), and c) recording pulse width control for controlling the pulse width of the entire recording pulse train by the output from the pulse width detecting means. Means 2 and d) recording power control means for controlling the power of the light source at the time of recording by the output from the pulse width detecting means. And wherein the door.

(2) A data pattern which does not become at least the shortest pit and the shortest gap is recorded / reproduced in a specific area on the recording medium, the pulse width of the pit or the gap is measured, and the recording power is adjusted so that this value becomes an optimum value. Control and control to uniformly reduce or increase the entire recording pulse train, then record / reproduce an isolated pattern of the shortest pit or shortest gap in a specific area on the recording medium, and measure the pulse width to find the optimum value. Therefore, the pulse width of the shortest pit and the shortest gap in the recorded data sequence is controlled so that

(3) Using a semiconductor laser or the like as a light source,
In an optical memory device for recording / reproducing information by a pit edge recording method in which information is provided on both edge portions of pits formed on a medium, a) detecting the pulse width of a pit portion or a gap portion between pits from reproduced data Pulse width detection means; b) recording control means for controlling the recording pulse width and the output of the light source by the output from the pulse width detection means; and c) the reproduction system equalizer circuit by the output from the pulse width detection means. It is characterized by comprising reproduction control means for controlling a constant and d) pulse generation means for generating a pulse for recording a pit for reproduction pulse width detection.

(4) While the equalizer in the reproduction control means is not operating, the shortest pit and the data pattern that is not the shortest gap among the modulated data patterns are recorded in a predetermined area on the recording medium, and the formed pit is reproduced. After measuring the pulse width and controlling the recording means to optimize this value, the shortest isolated pattern is recorded in a specified area on the recording medium, and the formed pits are reproduced to produce a pulse. The width is measured, and the constant of the equalizer circuit in the reproducing means is controlled so that this value becomes optimum.

[0009]

【Example】

(Embodiment 1) FIG. 1 shows a block diagram of claim 1 of an optical memory device of the present invention. Reproduction data 10 is input from the terminal 9 and recording pulse 8 is input from the terminal 7. The recording pulse width control means 1 of 2 controls the pulse width of the shortest pit and the shortest gap in the recording pulse. The recording pulse width control means 2 of 3 performs control to uniformly increase or decrease the pulse width of the entire recording pulse. The recording power control means 4 controls the power during recording. The semiconductor laser drive circuit 5 outputs the recording pulse width control means 2 and the recording power control means,
The semiconductor laser 6 is driven. The pulse width detection means 1 detects the pulse width of the pit portion or the inter-pit portion of the reproduction data 10, and the pulse width signal 11 is recorded by the recording pulse width control means 1 of 2, the recording pulse width control means 2 of 3, and the recording. Output to the power control means 4.

FIG. 2 shows a circuit diagram of one embodiment of the recording pulse width control means 1 and the recording pulse width control means 2. A portion 2 surrounded by a dotted line in the drawing is a recording pulse width control means 1 and a portion 3 is a recording pulse width control means 2. Recording pulse 1 from terminal 12
3 is input. The shortest pit detection circuit 14 detects the shortest pit from the recording pulse 13, and the pulse width control circuit 15 controls the pulse width of the shortest pit. On the other hand, the shortest gap is detected by the shortest gap detection circuit 17, and the gap width control circuit 18 controls the gap width of the shortest gap. Then, the pulse synthesizing circuit 16 synthesizes the pulses to obtain the recording pulse 19 in which the widths of the shortest pit and the shortest gap are controlled.

Next, the recording pulse width control means 2 will be described. Reference numeral 22 denotes a delay element, which produces a signal 24 obtained by delaying the recording pulse 19. The delay time is determined by the control signal 21 input from the terminal 20. By ANDing the recording pulse 19 and the delayed signal 24 by the AND gate 23, the recording pulse 25 whose pulse width is shortened by the delay time of the delay element 22 is output from the terminal 26. In this embodiment, the recording pulse width control means 2 is a circuit for shortening the recording pulse, but in the case of uniformly lengthening it, an OR gate may be used instead of the AND gate. Of course, the pulse width may not be changed depending on the situation. FIG. 3 shows the signal waveform of each part of the recording pulse width control circuit 2 in FIG.

FIG. 4 shows the shortest pit detection circuit 14 in FIG.
It is a concrete circuit diagram of one example. In addition, FIG.
3 is a signal waveform diagram of each part of FIG. The operation of the circuit will be described below with reference to these figures. The circuit consists of a shift register and a logical operation element. A recording pulse 28 is input to the terminal 27, and a write clock 30 is input to the terminal 29. Three
From each of the shift registers 1 to 36, signals 37, 38, 39, 40, 41, 4 obtained by sequentially shifting the recording pulse 28 are provided.
2 is output. Here, the signal shifted by one stage is S1,
The signal shifted by 2 steps is S2, and the signal shifted by 3 steps is S
A signal shifted by 3, 4 stages is S4, a signal shifted by 5 stages is S5, and a signal shifted by 6 stages is S6. In this example, 1-7 modulation is assumed as the modulation method. When the 1-7 modulated data is recorded on both edges, the shortest pit data pattern becomes "101", so the recording pulse is "H" for two write clocks. The shift register output patterns S1 to S6 are changed to "LHHL" by the logic element 43.
The signal 44 is output at the time of LL ". This signal is the case where the leading edge is isolated at the shortest pit. Further, the signal 46 is output by the logic element 45 when the pattern is" LLLHHL ". Is the case where the trailing edge is isolated at the shortest pit.
Is the case where both edges are isolated. Signals 44, 4
6 has a pulse width of one half of the input, that is, one clock, and the timing is also different, the shift registers 47, 48, 49,
The shortest pit pulse is shaped by 50, 51, 52, 53 and AND gates 54, 55. The shortest pit pulse 57 whose front edge is isolated from the terminal 56 is
Shortest pit pulse 59 whose rear edge is isolated from 8
Is output.

Next, the pulse width control circuit will be described.
FIG. 6 shows a specific circuit example of an embodiment of the pulse width control circuit. Further, FIG. 7 shows the signal waveforms of the respective parts of FIG. The isolated shortest pit signal 62 is input from the terminal 61. The shortest pit width is Tp, and the delay time of the delay element 63 is t
1 and the delay time of the delay element 66 is t2. However, between these values, 0 ≦ t1 <t2 ≦ Tp, t
There is a relation of 1 + t2 = Tp.

The AND gate 65 outputs signals 62 and 62 to t
By taking the AND of the signal 64 delayed by 1,
From the terminal 71, the pulse signal 70 whose rising edge is shorter than Tp by t1 is output. Meanwhile, gate 6
The signal 6 by 8 and the signal 6 obtained by delaying 62 by t2
By taking the AND of the inverted signal of 7
Outputs a pulse signal 75 whose falling edge is shorter than Tp by t1. Also, AND gate 69
By taking the AND of the pulse signals 70 and 75 at
A pulse signal 72 in which both rising and falling edges are shortened by t1 with respect to p is output from a terminal 73. The circuit selects these three signals.

In FIG. 2, the shortest gap detection circuit 17
Can be realized by a circuit similar to the shortest pit detection circuit of FIG. The gap width control circuit 18 can also be realized by a circuit similar to the pulse width control circuit of FIG.

FIG. 8 shows a circuit diagram of an embodiment of the recording power control means and the semiconductor laser driving means of the present invention. A portion 4 surrounded by a dotted line in the drawing is a recording power control means, and 5 is a semiconductor laser driving means. First, the fourth recording power control means will be described. A pulse width detection signal 77 is input from the terminal 76. Based on the pulse width detection signal 77, the CPU 78 gives the D / A converter 79 data for determining the pulse current at the time of recording. The D / A converter 79 converts the signal 80 into an analog control signal. A constant current circuit is composed of the operational amplifier 81, the transistor 82, and the resistor. Since the current value is determined by the analog signal 80, the recording power can be controlled by changing the data given to the D / A converter 79.

Next, the semiconductor laser driving means 5 will be described. A recording pulse 86 is input from the terminal 85. Here, the recording pulse is a pulse whose pulse width is controlled by the recording pulse width control means 1 and 2 described above. The digital element 87 has a non-inverted output 88 when the input is "H".
Becomes "H", the inverted output 89 becomes "L", and the input becomes "L".
At the time of, it operates so that the non-inverted output becomes "L" and the inverted output becomes "H". Switching of the pulse current 83 is performed by the transistors 90 and 92. When the recording pulse is "H", the transistor 92 is turned on, the transistor 90 is turned off, and the pulse current flows into the semiconductor laser 6. At this time, the optical output of the semiconductor laser becomes a high output level during recording.
On the contrary, when the recording pulse is "L", the transistor 92 is turned off and the transistor 90 is turned on, and the pulse current flows into the resistor 91.

(Embodiment 2) FIG. 9 shows a flow chart of a recording pulse control method of an optical memory device according to a second aspect of the present invention. The control method will be described below with reference to the flowchart. When the control is started, the initial values of the recording power and the recording pulse width are set at 101. At 102, pattern 1 is recorded. The pattern recorded here is a pattern that does not become the shortest pit or the shortest gap. For example, consider 1-7 modulation with double-edge recording as a modulation method. In 1-7 modulation, 1 to 7 0s can be set between 1 and 1. Therefore, if the data pattern is "101",
Since it becomes the shortest pit or the shortest gap, a pattern other than this, for example, "10001" may be selected. The ideal reproduction pulse width at this time is T01.

Here, a recording area will be described.
FIG. 10 shows a magneto-optical disk format standardized by ISO. One sector has 1024 bytes. 115 ODF Flag and Gaps in FIG.
FIG. 10B shows a magnified area called "."
Gap of 116 and 117 usually does not record anything. 11
The ALPC area 8 is an area which can be freely used by the user to correct the output of the semiconductor laser of the light source. The recording / reproducing of the pattern can be performed by using the areas not used for the normal recording / reproducing. It is also possible to use an unused user data area.

Returning to FIG. 9, the explanation of the control will be continued. At 103, the pattern 1 recorded previously is reproduced and the pulse width T1 is detected. At 104, a deviation amount dT = T01-T1 between the ideal pulse width T01 and the reproduction pulse width T1 is calculated. 105
Then, it is determined whether the deviation amount dT is within the allowable range. No, that is, if it is determined that the allowable range is exceeded, 106
Move on to the judgment.

In step 106, it is judged whether or not the deviation amount dT is larger than Te1. This judgment is used to select whether to control only the power as the control of the recording pulse or to control both the power and the pulse width. The recording pulse width is controlled by switching the delay time of the delay element as described above, but it is difficult to perform fine control, so it is effective to make large adjustments with the pulse width and fine adjustments with power. . When the deviation amount dT is larger than Te1, the pulse width of 107 and the recording power of 108 are adjusted. When dT is Te1 or less, the recording power of 109 is adjusted. After completion of the adjustment, the process returns to 102 again to record the pattern 1, the reproduction pulse width is detected, and the deviation amount is set within the allowable range.

FIG. 11 shows the relationship between the recording power and the reproduction pulse width. When the power is near the optimum power, as shown by the solid line 119, there is a linear relationship between the recording power and the reproduction pulse width. Tc is the ideal reproduction pulse width, and the area indicated by 120 is the allowable range. First, recording is performed with the recording power Pa to obtain the reproduction pulse width Ta. First, if the recording power is adjusted and then the reproduction pulse width Tc is obtained by recording with Pb, the equation representing the straight line 119 is obtained from these two quantities, and the optimum power Pc can be calculated. . Figure 9 again
Returning to step 105, when dT is judged to be within the allowable range at 105, the pattern 2 recording at 110 is started. The area to be recorded is the same as in the case of the pattern 1 described above. Pattern 2 is a pattern having the shortest pit or the shortest gap. For example, in the case of 1-7 modulation, it becomes "101". The reproduction pulse width T2 is detected at 111, and the deviation amount dT = T02-T2 between the ideal reproduction pulse widths T02 and T2 is calculated at 112. At 113, it is determined whether the deviation amount dT is within the allowable range. If No, that is, if it is determined that the allowable range is exceeded, the recording pulse width of 114 shortest pits and gaps is adjusted. And then back to 110 pattern 2 recording again,
Repeat steps 110 to 114 until dT is within the allowable range. When the result in 113 is Yes, that is, within the allowable range, the control ends.

FIG. 12 shows the relationship between the recording pulse width control amount and the reproduction pulse width change amount. This is the case where the straight line 121 is a long pattern other than the shortest pit and the shortest gap. The recording pulse width control amount and the reproduction pulse width change amount match.
Reference numeral 122 denotes the shortest pit and the shortest gap, in which the reproduction pulse width change amount with respect to the recording pulse width control amount is smaller than that of the long pattern. In the experiment, the proportional constant was about 0.5. This means that the precision of setting the pulse width of the shortest pit and the shortest gap shown at 122 is half that of other patterns. Therefore, the shortest pit and the shortest gap can be controlled with sufficient accuracy even if the pulse width is used.

(Embodiment 3) FIG. 13 shows a block diagram of an optical memory device according to a third aspect of the present invention. First, recording is performed by the recording control unit 203 with the recording pulse 208 of the pattern that does not form the shortest pit and the shortest gap created by the pulse generation unit 204. The recording control unit 203 controls the semiconductor laser with a predetermined light output.
The recorded pit is reproduced, and the reproduction signal 204 of the pit recorded on the recording medium is input from the terminal 205. After the reproduction control means 201 controls the reproduction system signal processing, the pulse width detection means 202 detects the reproduction pulse width of the pit. The recording control means 203 controls the recording conditions so that the output 207 of the pulse width detection means 202 becomes an optimum value. When the control of the recording system by the recording control means 203 is completed, recording is performed by the recording pulse of the shortest pit pattern created by the pulse generation means 204, and the reproduction control means 201 is detected by the pulse width detection means 202. The reproduction condition is controlled so that the pulse width becomes the optimum value, and the reproduction condition is controlled to the optimum condition.

FIG. 14 shows a circuit diagram of an embodiment of the pulse width detecting means, and FIG. 15 shows signal waveforms of respective parts of FIG. Terminal 2
The reproduction pulse 210 is input from 09. As shown in FIG. 3, this signal is a signal that becomes "H" at the pit 211, and the rising edge of the signal is the front edge of the pit.
The falling edge of the signal corresponds to the trailing edge of the pit. The inverter 212 produces a signal 213 by inverting the reproduction pulse 210. Reference numerals 214 and 215 are open collector type buffers. Reproduction pulse 210
Is "L", the output of the buffer 214 is GND and the output of the buffer 215 is open. On the contrary, when the reproduction pulse 210 is "H", the buffer 214
Output is open and the output of buffer 215 is GN.
It becomes D.

The transistor 216 and the resistors around it form a constant current circuit. The constant current generated by this constant current circuit is switched by the transistors 217 and 218. Transistor 2 when playback pulse 210 is "L"
17 turns on and transistor 218 turns off, causing a constant current to flow into the resistor connected to the collector of transistor 217. On the contrary, when the reproduction pulse 210 becomes "H", the transistor 217 turns off and the transistor 21
8 is turned on, and a constant current flows into the capacitor 219 connected to the collector of the transistor 218 to generate a voltage.

The delay element 220 outputs the signal 213 to the time T.
A signal 221 delayed by 1 is created. Nand gate 22
2 produces a reset signal 223 from signals 213 and 221. When the reset signal 223 is "L", the output of the buffer 224 becomes GND and is reset. When the reset signal 223 is "H", the output of the buffer 225 is in an open state, and the constant current described above causes the capacitor 2
The signal 226 rises like a ramp when flowing into 19, and maintains a constant value when a constant current does not flow. In addition, the operational amplifier 227 outputs the signal 226 to the A / D
This is a buffer to be input to the converter 229. The operational amplifier 227 is of a high input impedance type, such as FE.
Use the one with T input. The signals 226 and 228 have the same voltage.

On the other hand, the reproduction pulse 2 is reproduced by the delay element 230.
10 is delayed by time T2, and the one-shot multivibrator 2 is generated at the falling edge of this signal.
31 produces a pulse 232 of width T3. The A / D converter 229 outputs the digital data 233 obtained by A / D converting the signal 228 to the terminal 234. The digital data 233 is latched with the pulse 232.

Next, one embodiment of the reproduction control means will be described. FIG. 16 shows a circuit diagram of the equalizer portion of the reproduction control means of the present invention. A method of adjusting the equalizer will be described. Here, the equalizer is generally expressed by the following equation.

Vout (t) = Vin (t) −k {Vin (t + τ) + Vin (t−τ)} where 0 ≦ k ≦ 1 and τ is the delay line delay time terminal 235 and the reproduction signal 236 is input. It here,
It is assumed that the output impedance of the preceding amplifier connected to the terminal 235 is sufficiently small. Resistors 237, 238, 2
The following relationships exist between 39, 240, and 241.

R2 = R3 = R4 R1 = 7 * R2 R0 = R1 + R2 + R3 + R4 Further, the characteristic impedance of the delay line 242 is set to be the same as the parallel resistance of R0 and (R1 + R2 + R3 + R4). 243 is a differential amplifier. Since the input impedance is sufficiently larger than the characteristic impedance of the delay line, the signal that has passed through the delay line is totally reflected at the + input terminal and then passes through the delay line again. The signal 244, which is the differential signal of the + -input terminals, is output to the terminal 245. 2 to the + input terminal
The signal 247 that has passed through the delay line 242 of the signal of 46
Is entered. The output (OUT) signal 248 of the analog multiplexer 249 is input to the input terminal.

Here, the analog multiplexer 249 selects and outputs one output from the four inputs I1, I2, I3 and I4. Select signal 2 input from terminal 250
The signal to be selected is determined by 51. As shown in the figure, the signals divided by R1 to R4 are input to I1 to I4. Further, since the resistors have the above-described relationship, when the signal of 246 is V0, the input signals are as follows. The constant k that determines the characteristics of the equalizer when each input is selected is as follows.

I1 = 0.3V0, k = 0.3 I2 = 0.2V0, k = 0.2 I3 = 0.1V0, k = 0.1 I4 = 0, k = 0 FIG. The relationship between the value and the reproduction pulse width is shown. This figure shows the case where the shortest pit is reproduced. T02 indicated by the straight line 252 is the ideal value of the reproduction pulse width. As the value of k is increased as indicated by the straight line 253, the effect of the equalizer becomes remarkable and the reproduction pulse width becomes shorter. Although not shown in the figure, the Z-CA
It is also possible to support formats such as the V format, which have different transfer rates inside and outside the disc.

FIG. 18 shows an embodiment of the pulse generating means of the present invention. Further, FIG. 19 shows signal waveforms of respective parts of FIG. The sector mark detection circuit 254 detects a sector mark from the prepit reproduction signal input from the terminal 255 and outputs a sector mark signal 256. The write clock generation circuit 257 generates a write clock 258 required for recording. The counter 259 creates the timing of generating the recording pulse, and is reset by the sector mark signal 254 and reaches a certain value.
The output of 0 is made "H". 261,262,263,2
Reference numerals 64, 265 and 266 are D-flip-flops.
These are also reset by the sector mark.

268 pattern selection signals are input from the terminal 267. When the pattern selection signal 268 is "H", the shortest pit pattern is selected. At this time, the output 2 of the D-flip-flop 261 is output by the logic element 272.
69 is "H", output 2 of D-flip-flop 264
Shortest pit pulse 270 that becomes "H" while 71 is "L"
Then, the recording pulse 276 is output from the terminal 277. Since 2-7 modulation is assumed as the modulation method in this embodiment, the shortest pit pulse is three write clocks. FIG. 19 shows the signal waveform of each part in this case.

On the other hand, when the pattern selection signal 268 is "L", a pattern other than the shortest pit is selected. In this embodiment, pulses for five write clocks are created.
The logic element 273 obtains a pulse 274 in which the output 269 of the D-flip-flop 261 is “H” and the output 278 of the D-flip-flop 266 is “H” while it is “L”, and the recording pulse 276 is the recording pulse 276. Is output from.

(Embodiment 4) FIGS. 20 and 21 are flowcharts of a recording / reproducing control method for an optical memory device according to the present invention. The control method will be described below with reference to these flowcharts. When the control is started, the recording power and the initial value of the pulse width are set at 279. Next, at 280, pattern 1 is recorded. Here, the pattern to be recorded is a pattern in which the recorded pit does not become the shortest pit or the shortest gap. For example, when the 2-7 modulation is used as the data modulation method, the modulation data of the shortest pit is "10".
Since this is the case of "01", a pattern other than this may be selected. The area for recording the above pattern is as described in the first embodiment.

Next, the recorded pit is reproduced and the pulse width T is measured at 281. Pulse width T measured at 282
The deviation amount dT1 = T−T1 from the ideal value T1 is calculated.
At 283, it is determined whether the deviation amount dT1 is smaller than the allowable range e0. When No, that is, when it is determined that the allowable range is exceeded, the process proceeds to the determination of 284. At 284, it is determined whether the deviation dT1 amount is larger than e1. This is to judge whether only the recording power is required to control the recording means, or whether it is necessary to control both the recording pulse width and the recording power. Yes
In this case, the recording pulse width control of 286 is performed, and then the recording power control of 285 is performed. 28 for No
5 recording power control is performed. And then back to 280,
The loop is repeated until the deviation amount dT1 becomes smaller than e0. When the deviation amount dT1 becomes smaller than e0, the control of the recording system ends.

FIG. 22 shows the relationship between the recording power and the reproduction pulse width. The line 292 is the ideal value T1. ± e0
Is an allowable range, and e0 <e1. When the line 293 is recorded with the pulse width t1, the line 294 is the pulse width t2
The relationship between the recording power and the reproduction pulse width when the straight line 295 is recorded with the pulse width t3. Here, t1 <t2 <t3.

In the initial setting, it is assumed that the state of "a" is obtained when recording is performed with the recording pulse width t1. Since the deviation amount is larger than e1, the recording pulse width and the recording power are controlled. When the recording pulse width is increased from t1 to t2, the state becomes b, and by further increasing the recording power, the state becomes c. The amount of deviation at this time is smaller than ± e0. The slope of the straight line 294 is predetermined as a constant, but may vary depending on the device and the disc. Even in such a case, if the recording power is changed twice and the reproduction pulse width is measured, the slope of the straight line can be found. Therefore, if the recording power is changed up to three times, the reproduction pulse width T should be kept within the range of T01 ± e0. Is possible.

When the control of the recording means is completed, the control of the reproducing means of FIG. 21 is started. Here, the terminals labeled A in FIGS. 20 and 21 are connected. First, at 287, the pattern 2 is recorded. The area to be recorded is the same as in the case of the pattern 1 described above. Here, the pattern 2 is the shortest pit in the modulated data. Considering 2-7 modulation as the modulation method similar to the case of pattern 1, the shortest pit is the case of "1001". Also, 1
In the case of -7 modulation, the pattern is "101".
Next, at 288, the reproduction pulse width T is measured. At 289,
The difference dT2 = T−T2 between T and the ideal value T2 is calculated.

At 290, it is determined whether the deviation amount dT2 is smaller than the allowable range e2. If No, that is, the allowable range is exceeded, the equalizer 291 is adjusted. dT
When 2 is positive, that is, when the reproduction pulse width is wider than the ideal value, this is because the k of the equalizer is too small, so the value of k is increased. On the contrary, when dT2 is negative, the reproduction pulse width is narrower than the ideal value. This is because the value of k of the equalizer is too large and is overcompensated, so the value of k is reduced. After changing the equalizer k in this way, the reproduction pulse width of 288 is measured again, and when the deviation amount dT2 becomes smaller than e2, Y is set at 290.
The control becomes es. For example, as shown in FIG. 17, if k = 0.1 and the state of a is initially set, k
If the value is changed to 0.2, the deviation amount of the reproduction pulse width is set to ± e2.

[0043]

As described above, according to the present invention, the pulse width when reproducing the shortest pit and the gap does not deviate from the optimum value, so that there is an effect that stable data reading and writing can be performed. Further, according to the present invention, even when the ZCAV format in which the recording area is divided in the radial direction into several parts in the radial direction and the capacity per one turn increases from the inner circumference to the outer circumference, the present invention is used. The recording power and pulse width can be controlled so that optimum recording and reproduction can be performed in each area.

Further, there is an effect that it is not affected by changes in the surrounding environment or changes with time. Furthermore, the control of the recording / reproducing system is automatically performed by actually recording / reproducing pits on / from the disc, and the adjustment at the time of assembling becomes unnecessary, so that the man-hours at the time of assembling and adjusting the apparatus can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an optical memory device according to claim 1 of the present invention.

FIG. 2 is a circuit block diagram of an embodiment of the recording pulse width control means 1 and the recording pulse width control means 2 of the optical memory device of the present invention.

3 is a signal waveform diagram of each part of the recording pulse width control circuit 2 in FIG.

FIG. 4 is a circuit diagram of an embodiment of a shortest pit detection circuit according to the present invention.

5 is a signal waveform diagram of each part of FIG.

FIG. 6 is a circuit diagram of an embodiment of a pulse width control circuit according to the present invention.

FIG. 7 is a signal waveform diagram of each part in FIG.

FIG. 8 is a circuit diagram of an embodiment of recording power control means and semiconductor laser driving means of the optical memory device of the present invention.

FIG. 9 is a flowchart of an embodiment of a recording pulse control method according to claim 2 of the present invention.

FIG. 10 is a format diagram of a magneto-optical disk.

FIG. 11 is a diagram showing the relationship between recording power and reproduction pulse width.

FIG. 12 is a relationship diagram of a recording pulse width control amount and a reproduction pulse width change amount.

FIG. 13 is a block diagram of an optical memory device according to claim 3 of the present invention.

FIG. 14 is a circuit diagram of an embodiment of pulse width detection means.

FIG. 15 is a signal waveform diagram of each part of FIG.

FIG. 16 is a circuit diagram of an embodiment of reproduction control means.

FIG. 17 is a diagram showing the relationship between the equalizer k and value and the reproduction pulse width.

FIG. 18 is a circuit diagram of an embodiment of pulse generation means.

FIG. 19 is a signal waveform diagram of each part of FIG. 18.

FIG. 20 is a flowchart showing a recording / reproducing control method of the optical memory device according to claim 4 of the present invention.

FIG. 21 is a flowchart showing a recording / reproducing control method of the optical memory device according to claim 4 of the present invention.

FIG. 22 is a relationship diagram between recording power and reproduction pulse width.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 reproduction control means 2 pulse width detection means 3 recording control means 4 pulse generation means 5 semiconductor laser drive means 6 semiconductor laser 201 reproduction control means 202 pulse width detection means 203 recording control means 204 pulse generation means

Claims (4)

[Claims] 1. An optical memory device for performing recording by a pit edge method in which information is provided on both edge portions of a pit by using a semiconductor laser or the like as a light source, and reproducing data by a second differential method, wherein: a) reproduced data Pulse width detection means for detecting the pulse width of the pit portion or the gap portion between the pits, and b) recording pulse width control for controlling the recording pulse width of the shortest pit and the shortest gap by the output from the pulse width detection means. Means 1, c) recording pulse width control means 2 for controlling the pulse width of the entire recording pulse train by the output from the pulse width detecting means, and d) light source at the time of recording by the output from the pulse width detecting means. And a recording power control means for controlling the power of the optical memory device. 2. A recording power is controlled so that a data pattern which does not become at least the shortest pit and the shortest gap is recorded and reproduced in a specific area on a recording medium, and a pulse width of the pit or the gap is measured so that this value becomes an optimum value. Then, control is performed to uniformly reduce or increase the entire recording pulse train, and then the shortest pit or shortest gap isolated pattern is recorded / reproduced in a specific area on the recording medium, and the pulse width is measured and this value is determined to be the optimum value. 2. The recording / reproducing control method for an optical memory device according to claim 1, wherein the pulse widths of the shortest pit and the shortest gap in the recording data string are controlled so that 3. An optical memory device for recording / reproducing information by a pit edge recording method in which a semiconductor laser or the like is used as a light source, and information is provided on both edge portions of pits formed on a medium. Width detecting means for detecting the pulse width of the gap portion between the parts or pits, b) recording control means for controlling the recording pulse width and the output of the light source by the output from the pulse width detecting means, and c) the pulse. It is characterized by comprising reproduction control means for controlling the constant of the equalizer circuit of the reproduction system by the output from the width detection means, and d) pulse generation means for generating a pulse for recording a pit for reproduction pulse width detection. And optical memory device. 4. The shortest pit in the modulated data pattern and the data pattern that is not the shortest gap are recorded in a predetermined area on the recording medium while the equalizer in the reproduction control means is not operated, and the formed pit is reproduced. After measuring the pulse width and controlling the recording means to optimize this value, the shortest pattern that is isolated in a specified area on the recording medium is recorded, and the formed pit is reproduced to obtain the pulse width. Is measured, and the constant of the equalizer circuit in the reproducing means is controlled so that this value becomes optimum,
A recording / reproducing control method for an optical memory device according to claim 3.