JP2002319137A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device improving the deterioration of performance such as the increase of access time generated by the variance of the disk and the impossibility of data reproduction, by preventing too much or too little of the amplitude of a reproduced signal at the time right after the start of the AGC operation. SOLUTION: The device is furnished with an amplitude control means for controlling the reproducing signal produced by an optical head to the amplitude suitable for an information reproducing means, a waveform equalizing circuit 107 for equalizing the waveform of the reproduced signal, an amplitude detecting circuit 109 for measuring the amplitude of the equalized signal, and the information reproducing means for extracting the information from the equalized signal. In the amplitude control means, the gain fixing function for optionally fixing the gain of an AGC circuit 105 and a gain setting circuit 106 are furnished. The amplitude of the equalized signal, the gain of which is settled by this gain fixing function, is measured by the amplitude detecting circuit 109, then the gain value learning function is provided for adjusting the gain setting so as to become the amplitude of the equalized signal suitable for the information reproducing means while changing the setting to the gain setting circuit 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus for performing recording and reproduction, and more particularly to a field of signal processing having a function of controlling a reproduction signal amplitude.

[0002]

2. Description of the Related Art In recent years, the density of optical discs has been accelerated, and accordingly, in the field of signal processing, Viterbi decoding and PRML (Partial Response M / L) have been required.
Digital signal processing techniques such as aximumLikelihood) are being used. In these signal processing techniques, an A / D converter is required to convert a reproduced signal, which is an analog signal, into a multi-valued digital signal.
The information in the amplitude direction is important information together with the information in the time axis direction of the reproduction signal. That is, inputting a reproduction signal with an optimum amplitude with respect to the dynamic range of the A / D converter is a necessary condition for performing optimum digital signal processing.

In a read-only disk such as a DVD or a CD in which a signal is present without interruption, the amplitude of the reproduced signal can be kept almost constant by always configuring an AGC circuit. However, in a rewritable disk such as a DVD-RAM, since there is an unrecorded area, operating the AGC circuit constantly causes saturation of the AGC circuit or depletion of the gain. If the reproduction of the signal is started in this state, since the AGC circuit is in an improper state, it takes time to return to an appropriate amplitude of the reproduced signal, and reproduction failure or a retry occurs, thereby deteriorating the performance of the apparatus.

In order to avoid such a state, the gain of the AGC circuit is fixed to one appropriate gain in the reproduction standby state, or the response of the AGC circuit is made faster at the start of reproduction, so that For example, the configuration is provided with a switching function for setting an appropriate reproduction signal amplitude to an appropriate value.

[0005]

However, in the above-described configuration in which the gain of the AGC circuit is fixed, the phenomenon that the amplitude of the reproduction signal differs for each disk due to variations in the reflectance and modulation rate of the disk is described. Immediately after the start of reproduction, that is, immediately after the start of the AGC operation, the amplitude of the reproduced signal does not become appropriate. As a result, the data cannot be reproduced or the amplitude of the reproduced signal is too short or short immediately after the start of reproduction,
There has been a problem that the access time is increased due to the retry and the reproduction performance of the apparatus is deteriorated.

SUMMARY OF THE INVENTION In view of the above problems, the present invention prevents the amplitude of a reproduction signal from being excessively short or short immediately after the start of an AGC operation, and improves the access time caused by the disc variations and the performance deterioration such as the inability to reproduce data. It is intended to provide a device.

[0007]

In order to solve the above-mentioned problems, an optical disk device of the present invention has the following configuration. Amplitude control means for controlling a reproduction signal generated by the optical head to have a predetermined amplitude, waveform equalization means for equalizing a signal output by the amplitude control means, and an equalization signal output by the waveform equalization means. An amplitude measuring means for measuring the amplitude and an information reproducing means for extracting information from the equalized signal are provided.
The amplitude control means includes an amplification circuit, a gain control means for determining a gain of the amplification circuit, and a holding means for holding control of the amplitude control means, and the gain control means holds the control of the amplitude control means. A fixed gain function for fixing the gain of the amplifier circuit; and gain setting means for setting an arbitrary gain for the amplifier circuit when the gain of the amplifier circuit is fixed or when the amplitude control means holds the control. In addition. At the start of the apparatus, the amplitude measuring means measures the amplitude of the equalized signal according to the gain of the amplifier circuit determined by the gain setting means, and the amplitude of the equalized signal becomes suitable for the information reproducing means. And a gain value learning function for obtaining a set value of the gain setting means for setting the gain, and a process of setting the obtained set value to the gain setting means.

The optical disk apparatus further comprises a temperature detecting means for detecting the internal temperature, and the gain value learning is performed when the temperature detected by the temperature detecting means changes.

The apparatus has a reproduction signal amplitude control means, a gain setting means for setting a gain in the amplitude control means, and a storage element storing device individual information. A process of recording the gain setting value obtained by the gain value learning and the device individual information of the device in a specific area on the optical disk is performed.

[0010] The optical disc apparatus further comprises a temperature detecting means for detecting an internal temperature. The gain value learning is performed in accordance with a change in the temperature detected by the temperature detecting means. Is recorded in a specific area on the optical disk.

The apparatus has a collating means for reading the gain setting value and the device individual information existing in a specific area on the optical disk, and collating the device individual information with its own device individual information. Then, the read gain setting value is set in the gain setting means.

The apparatus includes a collating means for reading a gain set value, apparatus individual information, and temperature information existing in a specific area on the optical disc, and collating the individual apparatus information with its own apparatus individual information, and a temperature detecting means. When the information matches and the temperature detected by the temperature detecting means matches the temperature information, the read gain setting value is set in the gain setting means.

[0013] An apparatus having amplitude control means for a reproduction signal, gain setting means for setting a gain in the amplitude control means, and further comprising a storage element, wherein disc individual information described in a specific area of the optical disc is stored. Reading and gain value learning are performed, and the gain setting value and the disc individual information obtained by the gain value learning are stored in the storage element.

A temperature detecting means for detecting the internal temperature of the optical disk device is provided. Gain value learning is performed in accordance with a change in the temperature detected by the temperature detecting means, and a gain set value obtained by the gain value learning, Is stored in the storage element.

A discriminating means for reading disc individual information described in a specific area of the optical disc and comparing disc individual information with disc individual information stored in the storage element is provided. If there is, the gain setting value is set in the gain setting means.

A discriminating means for reading disc individual information written in a specific area of the optical disc, collating disc individual information with disc individual information stored in the storage element, and a temperature detecting means are provided. When the temperature detected by the temperature detecting means matches the temperature information stored in the storage element, the gain setting value read is set in the gain setting means.

[0017]

(Embodiment 1) Hereinafter, an optical disk device according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of the optical disc device according to Embodiment 1 of the present invention. 1, reference numeral 101 denotes an optical disk, and 102 denotes an optical disk 101.
An optical head including a laser for irradiating a laser beam, a focus and tracking actuator, and a photodetector for detecting return light from the optical disc 101; a focus error signal, a tracking error signal, and a reproduction signal 103 detected from a signal detected by the optical head 102; A signal generation circuit 104 that generates a signal is a servo controller that optimally controls the focus state and tracking state of the optical head and further controls the rotation state of the motor in accordance with the focus error signal and the tracking error signal.

Reference numeral 105 denotes an AGC circuit for controlling the amplitude of the reproduction signal to a predetermined amplitude; 106, a gain setting circuit for setting a gain when the AGC circuit is not operating; 107, a waveform equalization circuit for equalizing the waveform of the reproduction signal; Reference numeral 108 denotes an A / D converter for analog-to-digital conversion of a waveform-equalized signal; 109, an amplitude detection circuit for detecting the amplitude of a signal input to the A / D converter; 110, reproduction converted to a digital value A PLL circuit that extracts a clock component from a signal to generate a read clock, and synchronizes with the A / D conversion data to generate read data. A PLL circuit 111 reads data from the read clock and the read data extracted by the PLL circuit according to a modulation method. Is a data demodulation circuit for demodulating the data. A system controller 112 controls each block. 113 is a storage element. Reference numeral 114 denotes a laser control circuit that controls the amount of emitted laser light.

FIG. 2 is a block diagram showing the configuration of the AGC circuit 105 in detail. 2, reference numeral 201 denotes a voltage control amplifier, 202 denotes a resistor, 203 denotes a capacitor for holding a voltage that determines the gain of the voltage control amplifier 201, and 204 denotes a voltage according to the gain value output from the gain setting circuit 106 instantaneously. A switch for charging the capacitor 203; a high-pass filter 210 for removing low-frequency fluctuations contained in the equalized signal; a full-wave rectifier circuit 208 for full-wave rectification of the output of the high-pass filter 210;
Is a comparator, 209 is an amplitude setting circuit that outputs a comparison voltage of the comparator 207 according to the amplitude setting, and 206 is a capacitor 20 according to the output state of the comparator 207.
3 is a charge pump for charging and discharging current, and 205 is a charge pump 206 according to a hold signal.
And a switch for separating the capacitor 203 and the voltage control amplifier 201 from each other.

The main signal flow and the operation of the AGC circuit will be described with reference to FIGS. First, the usual
The case where the C circuit 105 operates as a loop will be described. After the reproduced signal generated by the signal generation circuit 103 is equalized by the waveform equalization circuit 107,
The threshold value of the comparator 207 is set in the amplitude setting circuit 209 so as to be optimal for the input range of the D converter 108. The comparison result of the output amplitude of the full-wave rectifier circuit 208 with respect to the output voltage of the amplitude setting circuit 209 according to the set threshold value is the output of the comparator 207. The charge pump 206 is controlled according to the state of the output of the comparator 207, and when the amplitude of the output of the full-wave rectifier circuit 208 is small (that is, the gain of the voltage control amplifier is low), the upper current source of the charge pump 206 is turned on. Capacitor 20
The voltage is increased by charging the current to No. 3 and the gain of the voltage controlled amplifier 201 is controlled to be increased. Conversely, if the output voltage of the full-wave rectifier circuit 208 is larger than the output voltage of the amplitude setting circuit 209, the charge pump 2
06 is turned on, the current is discharged from the capacitor 203 to lower the voltage, and the voltage control amplifier 2
Control is performed to decrease the gain of 01.

When the current value of the upper current source of the charge pump 206 is equal to the current value of the lower current source, the AGC circuit 1
Reference numeral 05 indicates that an equilibrium state is maintained when the high level and the low level of the output level of the comparator 207 continue to be equal, and the state of the optimum amplitude is maintained. When the current value of the upper current source of the charge pump is different from the current value of the lower current source, for example, in the case of 10: 1,
The AGC circuit 105 determines that the interval between the high level and the low level of the output level of the comparator 207 is also 10: 1.
Is maintained in equilibrium.

The resistor 202 is connected to the gain setting circuit 10.
Even if the potential of the capacitor 6 differs from that of the capacitor 203, the resistance value is set to a large value such that a current value sufficiently smaller than the current value of the charge pump 206 flows.

Next, a case where the loop of the AGC circuit 105 is broken will be described. When the optical disc 101 is a write-once disc or a rewritable disc, there is an unrecorded area where the amplitude of the reproduced signal is lost. for that reason,
When the AGC circuit 105 operates, the full-wave rectifier circuit 208
, The output of the comparator 207 is fixed, the charge pump 206 continues to discharge current, the voltage of the capacitor 203 increases, and the gain of the voltage control amplifier 201 also becomes maximum. In this state, when the recording operation is started and the reproducing operation is started, the voltage control amplifier 201
Is maximized, the amplitude of the equalized signal also saturates, and a signal exceeding the dynamic range is input to the A / D converter 108, so that the AGC circuit 105 normally operates. It is difficult to reproduce data until the amplitude of the coded signal becomes normal.

In order to prevent such a state, the switch 205 is turned off in an area other than the unrecorded area or during data reproduction, thereby cutting the loop of the AGC circuit 105 to a hold state. In the hold state, the current of the charge pump 206 charges the capacitor 203,
Since the capacitor 203 is not discharged, the voltage of the capacitor 203 is charged to the voltage output by the gain setting circuit 106 via the resistor 202, and the gain of the voltage control amplifier 201 also becomes a gain according to the voltage.

If the voltage output from the gain setting circuit 106 is close to the voltage of the capacitor 203 when the normal AGC circuit 105 is in an equilibrium state, it enters the recording area and closes the AGC loop to reproduce data. Even if you start
Since the equalized signal amplitude is close to the proper amplitude, data reproduction is possible without difficulty. Assuming that there is no resistor 202,
If the above hold state continues for a long time, the voltage of the capacitor 203 is gradually discharged due to the leakage current of the capacitor 203, the switch 205, or the voltage control amplifier 201, and finally reaches zero. At this time, since the gain of the voltage control amplifier 201 is minimum, it enters the recording area in that state and starts the reproducing operation.
Even if the loop of the GC circuit 105 is closed, the amplitude of the equalized signal is small, and it is still difficult to reproduce data until the AGC circuit operates normally and reaches an appropriate amplitude.

When the potential difference between the voltage of the gain setting circuit 106 and the capacitor 203 exceeds a certain level, a current larger than the above-described leakage current flows through the resistor 202 and the resistor 202 The current is set to be negligibly small. For example, assuming that the current of the charge pump 206 is 1 mA, the control voltage range of the voltage control amplifier is 1 V, and the total leakage current is 10 nA, it may be set to about 100 kΩ. With the configuration described so far, a certain degree of reliability can be realized in data reproduction from the unrecorded area into the recording area or in data reproduction immediately after holding the AGC circuit for a long time.

However, in the case of a removable medium such as an optical disk, the amplitude of a reproduced signal varies greatly due to variations in disk reflectance, variations in disk sensitivity, variations in data modulation, and contamination. for that reason,
In order to make the equalized signal input to the A / D converter 108 to an appropriate amplitude when the reproduced signal amplitude varies, the gain of the voltage control amplifier 201 must be made different depending on the disk. At this time, if the output voltage of the gain setting circuit 106 is kept constant, data reproduction from a non-recorded area to a recorded area or a long time A
In the data reproduction immediately after holding the GC circuit, if there is a certain difference between the voltage of the capacitor 203 by the gain setting circuit 106 and the voltage of the capacitor 203 having an appropriate equalized signal amplitude, data reproduction immediately after the start of reproduction is unstable. Becomes In this case, a reproduction retry may occur, or a reproduction error may occur in some cases.

In order to avoid such a situation, it is necessary to previously set the voltage of the gain setting circuit 106 to a voltage having an appropriate equalized signal amplitude according to the disk. A learning method for detecting and setting a voltage having an appropriate equalized signal amplitude will be described below using a DVD-RAM as an example.
In the present embodiment, the main learning will be referred to as AGC learning. In the DVD-RAM disk format, a predetermined number of drive test zones exist on the inner and outer circumferences of the disk, and the apparatus can independently perform recording laser power adjustment and servo adjustment in those areas. This disc format is described in DVD Specifications for Rewritable Disc Part1 V
er.2.0.

FIG. 3 is a flowchart of the AGC learning, and FIG. 4 is a diagram showing the operation of the method for detecting the amplitude of the equalized signal by the amplitude detecting circuit 109. The learning method will be described below with reference to FIGS. When the apparatus is started, the apparatus is in a state where normal recording and reproduction can be performed on the disk, and then the apparatus is moved to the drive test zone (step 301). A 6T signal is recorded for several sectors at the recording power (process 30).
2). At this time, the control of the apparatus, such as the focus state and the tracking state, must be made almost optimal. Here, it is assumed that 25 sectors, which is one round of the disk, are recorded. By recording one round of the disk, disturbance factors such as uneven recording sensitivity and surface runout in the circumferential direction in the disk can be averaged. Also, the 6T signal has almost the maximum amplitude in the modulated random signal,
Since it is hardly affected by a decrease in amplitude due to waveform equalization and is substantially a sine wave, it is one of the signals whose amplitude can be detected most easily.

Next, the amplitude of the waveform equalized signal of the recorded 6T signal is measured. In order to perform this measurement, first, the switch 204 is turned on with a gain fixed control signal,
The voltage control amplifier 201 is fixed to a gain corresponding to the voltage output from the gain value setting circuit 106 (process 303), the switch 205 is turned off by a hold signal, and an appropriate gain setting value (E0) for the gain value setting circuit 106 is set. Is set by the system controller 112 (process 304). At this time, the average full amplitude (S0) of the recorded 6T equalized signal is detected by the amplitude detection circuit 109.

FIG. 5 shows the relationship between the gain setting value of the gain setting circuit 106 and the output voltage.
FIG. 6 shows the relationship between the gain of 1 and the control voltage. When the switch 204 is turned on and the switch 205 is turned off, the output voltage of the gain setting circuit 106 becomes equal to the control voltage. As shown in FIG. 5, the gain setting circuit 106 can be configured by a D / A converter that operates so that the voltage increases in proportion to the gain setting. As shown in FIG. 6, the voltage control amplifier 201 is an amplifier whose gain increases in proportion to an increase in the output voltage of the gain setting circuit, that is, the control voltage. These gain setting ranges, output voltage ranges, and gain ranges are merely examples, and there is no problem even if the values are changed.

In FIG. 4, reference numeral 401 denotes an equalized signal of the recorded 6T signal, which is input to the A / D converter 108. A is the maximum value on the upper side, and B is the maximum value on the lower side, which is the input dynamic range of the A / D converter 108. The circles in FIG. 4 indicate sampling points for A / D conversion.
The sampling cycle is a data channel clock cycle T. When the 6T equalization signal 401 is sampled, upper peak points (A0), (A1), and so on from the zero level are obtained.
, (An), and lower peak points (B0), (B
1),..., (Bn) can be obtained as digital values.
Assuming that the average signal amplitude S of the equalized signal 401 is N, the sampling number is: S = | (A0 + A2 +... + An) / N | + | (B1 +
B2 + ... + Bn) / N | (process 307).

In this way, the total amplitude (S0) is measured,
It is determined whether (S0) is the optimum amplitude for the A / D converter 108. This determination is made by the system controller 112. The total amplitude (S
0) is acquired by the system controller 112. Also,
The upper limit (Sp) and the lower limit (Sb) of the equalized signal amplitude range appropriate for the input of the A / D converter 108 are stored in the storage element 113 in advance, and the (Sp) and (Sb) are used. Then, the system controller 112 determines whether or not the acquired amplitude (S) is within the range from (Sp) to (Sb) (determination 308). Here, the storage element 113
Is an EEPROM (Electrically Erasable Programmab)
le Read-Only Memory).

First, if (S) is within the range from (Sp) to (Sb), or (Sp) or (Sb), the voltage control amplifier 201 will determine the optimum amplitude for the disk that has just started. This means that the gain has been set to generate an equalized signal, and that the gain setting circuit 106 has also been set to an optimum gain value. In this case, the gain setting circuit 106 is kept set to (E0), the switch 204 is turned off, the AGC circuit 105 is returned to a normal state (process 312), and the learning ends.

If (S) is smaller than (Sb), the system controller 112 raises and sets the gain setting circuit 106 so as to increase the gain of the voltage control amplifier 201 (step 309). Amplitude detection circuit 10
Assuming that the amplitude of the 6T equalized signal detected in step 9 is (S), the amplitude detection circuit 109 measures (S) again with the gain increased (step 307). The measurement result (S) is determined in decision 31
At 3, it is detected whether the gain of the voltage control amplifier 201 is optimal. Here, if it is determined that the gain of the voltage control amplifier 201 is optimal, the learning is terminated, and the gain setting circuit 106 returns the AGC circuit 105 to the normal state while keeping the gain setting value (processing 312).

If (S1) exceeds (Sp), the set value (E0 in this case) of one step before is set in the gain setting circuit 106 (process 311), and the AGC circuit 105 is set to the normal value. The state is restored (process 312), and the learning ends. If (S1) is still smaller than (Sb),
In order to further increase the gain of the voltage control amplifier 201,
The set value of the gain setting circuit 106 is increased (process 309),
Continue learning with the same procedure. In this operation, the amplitude of the equalized signal is changed from (Sp) including (Sp) and (Sb) to (Sp).
Continue in the same manner until the value falls within the range up to b) or exceeds (Sp).

Next, when (S) is larger than (Sp), the system controller 112 lowers the setting of the gain setting circuit 106 so as to lower the gain of the voltage control amplifier 201 (step 310). ). With the gain reduced, the amplitude (S) of the equalized signal is detected by the amplitude detection circuit 1.
The measurement is performed again at 09 (process 307). Measurement result (S)
Detects whether the gain of the voltage control amplifier 201 is optimal in the judgment 314. Here, the voltage control amplifier 20
If it is determined that the gain of 1 is optimal, the AGC circuit 105 is returned to the normal state with the setting in the gain setting circuit 106 as it is (processing 312), and the learning is terminated.

Even if (S) is smaller than (Sb), the AGC circuit 105 is returned to the normal state with the gain set at that time (process 312), and the learning is terminated. If (S2) is still larger than (Sp), the set value of the gain setting circuit 106 is reduced so that the gain of the voltage control amplifier 201 is further reduced, and learning is continued in the same procedure. In this operation, the amplitude of the equalized signal is (Sp), (S
The same is continued until the value falls within the range from (Sp) to (Sb) including b) or becomes smaller than (Sb).

As described above, in the present AGC learning, the amplitude measurement result of the equalized signal is changed from the optimum amplitude range (Sp) to (Sb).
If not, or if it does not, the gain setting value of the gain setting circuit 106 is set so that the amplitude becomes small. This is to prevent the input dynamic range of the A / D conversion circuit 108 from being exceeded. However, (S
At times other than the optimal range from p) to (Sb), processing may be performed such that the amplitude is small, large, or closer to the optimal range.

As described above, by performing the AGC learning in the first embodiment of the present invention, the optimum equalized signal amplitude is obtained according to the disc in addition to the AGC operation, so that the AGC operation can be performed smoothly even immediately after the start of data reproduction. Can be migrated. Therefore, for the A / D conversion circuit, an optimum amplitude is obtained immediately after the start of reproduction, and a reproduction error or the like due to an excessive or insufficient amplitude can be prevented. Also, when the temperature inside the device changes, the amplitude of the reproduced signal and the equalized signal changes due to a change in gain due to the temperature characteristics of the reproducing circuit, a change in the intensity of light applied to the optical disk, and a change in tilt or the like generated on the disk. I do.

Even if the temperature inside the apparatus changes, the learning can be performed to absorb the change in the amplitude of the equalized signal caused by the cause, and always obtain the optimum equalized signal amplitude. I can do it. This temperature change can be easily realized if the system controller 112 monitors the change using a temperature detecting element such as a thermistor, for example.

In the first embodiment, the amplitude of an equalized waveform obtained by recording a 6T signal and reproducing the 6T signal is measured. Instead of the 6T, the amplitude of normal random data is measured. You may do it. In this case, the total amplitude can be measured by adding the following processing to the amplitude detection method shown in FIG.

The random signal contains data whose amplitude is smaller than the total amplitude such as 3T, 4T and 5T.
Try to exclude these amplitudes. When sampling the amplitude of the equalized signal, the T of the signal can be determined by counting the number of samples from one zero-cross point to the next zero-cross point. Only when this number of samples is 6 or more, the peak points (A1), (A2).
1), (B2),... Are detected. Also,
Since there are a plurality of peak points in 11T and 14T, it can be dealt with by acquiring only one peak point between the zero cross point and the next zero cross point.

By doing so, the above-described effects can be obtained even when the disc is a read-only disc and cannot record a 6T signal. Even on a recordable disc, if the location where the random signal was recorded is known, learning can be performed without recording by adding a similar process at that location. (302) can be omitted, and the learning time can be reduced.

In the first embodiment, the amplitude detection circuit 109 is configured to detect the equalized signal itself by using a sampled value sampled. However, other methods, for example,
Even if the upper envelope and the lower envelope of the equalized signal are taken and the difference between them is detected, the amplitude of the equalized signal can be detected and the same learning as described in the first embodiment can be realized.

(Embodiment 2) Next, Embodiment 2 will be described below. In the second embodiment, the method of AGC learning itself is the same as that shown in the first embodiment, and the configuration of the optical disc device is also the same as that shown in FIG. Description is omitted.

In a DVD-RAM disk, DIZ (Disc Identific) is stored in an area other than the user data area.
ation zone), and each device is permitted to record information independently. In the device, the storage element 113 stores a serial number representing the individual identification of the device. This may be performed at the time of device manufacturing or factory shipment.

After the learning described in the first embodiment is performed, the learning result, the serial number stored in storage element 113, and information indicating that the information is the AGC learning result are stored in DIZ. Record it. Here, the learning result is a gain setting value set in the gain setting circuit 106. The recorded DIZ information means that the amplitude of the optimum equalization signal obtained by the combination of the device and the disk is the optimum.

FIG. 7 shows a flowchart of the learning process of the optical disk device according to the second embodiment of the present invention, and the procedure will be described below with reference to FIG. Start the device (701),
Before performing the learning described in the first embodiment, the DIZ is reproduced (process 702). The presence or absence of the AGC learning result in the reproduced DIZ information is confirmed (decision 70).
3). If there is a learning result, the system controller 112 checks the own serial number stored in the storage element 113 with the serial number included in the information as a determining means (determination 704). If the serial numbers match, learning is once performed by the combination of the device and the disk, and the optimum amplitude of the equalized signal is known. Therefore, the gain setting value included in the information is set to the gain. The value is set in the setting circuit 106 (process 705), and the process ends. At this time, AGC learning is not performed.

If the information is not available in DIZ, or
If the serial numbers are different, AGC learning described in the first embodiment is performed in a similar procedure. After learning, D
IZ has its own serial number and learning result, and it is A
The information indicating that the result is the GC learning result is newly recorded, and the process ends. This makes it possible to omit the learning process the next time the device is started up by the combination of the device and the disk. Therefore, according to the second embodiment, not only the effects shown in the first embodiment can be obtained, but also the learning time in the learning shown in the first embodiment can be omitted depending on the combination of the device and the disk. Yes, it is possible to reduce the time required for the entire startup.

In the second embodiment, as described in the first embodiment, AGC learning is performed not only at the time of startup but also when the internal temperature of the apparatus changes, and the learning result and The temperature information is D together with the device individual information.
Record it in IZ. In the previously learned device and disk, when the internal temperature of the device changes and the temperature condition is met, the recorded learning result is set in the gain setting circuit 106 so that learning is performed again even when the temperature changes. Optimum gain setting can be achieved without any problem.

Third Embodiment Next, a third embodiment will be described below. Also in the third embodiment, AGC
The method of learning itself is the same as that shown in the first embodiment, and the configuration of the optical disk device is also the same as that shown in FIG. 1, so that the description thereof will be omitted.

After performing the learning described in the first embodiment, the learning result and the individual information of the learned disk are stored in the storage element 113. Here, the individual information of the disc is, for example, a maker that created the disc, and taking a DVD-RAM as an example,
It is described in the control area of the disc. The learning result is a gain setting value set in the gain setting circuit 106.

FIG. 8 shows a flowchart of the learning process of the optical disk device according to the third embodiment of the present invention, and the procedure will be described below with reference to FIG. Start the device (801),
Before the learning described in the first embodiment is performed, information in the control area, in particular, disc individual information is reproduced (process 802). Then, it is determined whether or not there is disc individual information in the information of the control area (determination 80).
3). If there is disc individual information, the same disc individual information as the reproduced disc individual information and the learning result are stored in the storage element 113 or the system controller 1
12 performs collation as a determining means (determination 804). If they are in storage element 113 and match,
The learning result (gain setting value) stored in the storage element 113 is set in the gain setting circuit 106 (step 80).
4), end the process. At this time, AGC learning is not performed.

If there is no disc individual information in the judgment 803, AGC learning is performed (process 806), and the process ends. If the information does not exist in the storage element 113 or does not match in the determination 804, the AGC learning described in the first embodiment is performed in a similar procedure. After the learning is completed, the learning result and the disc individual information are newly stored in the storage element 113, and the processing is terminated. This makes it possible to omit the learning process the next time a disc having this individual information is inserted. Therefore, according to the third embodiment, not only the effect shown in the first embodiment can be obtained, but also the learning time in the learning shown in the first embodiment can be omitted in the optical disc having the individual information. Yes, it is possible to reduce the time required for the entire startup.

The individual information of the disk shown in the third embodiment is not limited to the information of the maker, but is information indicating the characteristics of the recording film of the disk even if it is information indicating the stamper that manufactured the disk. There may be. These pieces of information are also a part of the factors that influence the amplitude of the reproduced signal, and thus are useful information for learning, and have the same effects as those described above.

In the third embodiment, as described in the first embodiment, the AGC learning is performed not only at the time of startup but also when the internal temperature of the apparatus changes, and the learning results and The temperature information is stored in the storage element 113 together with the disk individual information. In the previously learned disk, when the internal temperature of the apparatus changes and the temperature condition is met, the learning result stored in the storage element 113 is set in the gain setting circuit 106 so that the learning is performed again even when the temperature changes. The optimum gain setting can be performed without performing.

[0058]

As described above, according to the optical disk apparatus of the present invention, the change in the amplitude of the equalized signal can be reduced immediately after the start of data reproduction, and the optimum amplitude can be obtained immediately after the start of reproduction. In addition, it is possible to prevent a reproduction error or the like due to an excessive or insufficient amplitude.

As described in the second embodiment, by recording the learning result and the device information on a disc,
Learning can be omitted, and the start-up processing time of the device can be reduced while maintaining the above-described effects. Further, by recording the temperature information on the disc, it is possible to omit the process of re-learning even when the temperature changes, and to obtain the same effect as described above.

Also, as described in the third embodiment, the learning can be omitted by storing the learning result and the disc individual information in the device, and the starting of the device while maintaining the above-mentioned effects can be performed. Processing time can be reduced. Further, by adding the temperature information to the storage element and storing the information, and referring to the information, it is possible to omit the process of re-learning even when the temperature changes, and to obtain the same effect as described above.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an optical disc device according to first and second embodiments.

FIG. 2 is a block diagram illustrating a configuration of an AGC circuit.

FIG. 3 is a flowchart showing a flow of an AGC learning method according to the first and second embodiments;

FIG. 4 is a waveform chart showing the operation of the amplitude detection circuit.

FIG. 5 is a diagram illustrating an example of a characteristic of a gain setting circuit;

FIG. 6 is a diagram showing an example of characteristics of a voltage controlled amplifier.

FIG. 7 is a flowchart illustrating processing according to the second embodiment;

FIG. 8 is a flowchart illustrating processing according to the third embodiment;

[Explanation of symbols]

 Reference Signs List 101 optical disk 102 optical head 103 signal generation circuit 104 servo controller 105 AGC circuit 106 gain setting circuit 107 waveform equalization circuit 108 A / D converter 109 amplitude detection circuit 110 PLL 111 data demodulation circuit 112 system controller 113 storage element 114 laser control circuit 201 Voltage control amplifier 207 Comparator 206 Charge pump 209 Amplitude setting circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Konishi 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5D044 FG02 FG04 5D090 AA01 CC04 DD03 DD05 EE17 FF30 GG33

Claims (10)

[Claims] 1. An apparatus for reproducing information recorded on an optical disk or recording information on the optical disk by an optical head equipped with a laser for irradiating light on the optical disk, wherein the apparatus is generated by the optical head. Amplitude control means for controlling the reproduced signal to have a predetermined amplitude, waveform equalization means for equalizing the signal output by the amplitude control means, and measurement of the amplitude of the equalized signal output by the waveform equalization means. And an information reproducing unit that extracts information from the equalized signal. The amplitude control unit holds control of an amplifier circuit, a gain control unit that determines a gain of the amplifier circuit, and control of the control unit. And a gain control means for holding the control of the amplitude control means and fixing the gain of the amplifier circuit. Gain setting means for arbitrarily setting the fixed gain when the gain of the amplifier circuit is fixed or when the amplitude control means holds the control, wherein the gain setting means determines the gain when the apparatus is started. The amplitude setting means measures the amplitude of the equalized signal according to the gain of the amplifier circuit, and sets the gain of the amplifier circuit so that the amplitude of the equalized signal is suitable for the information reproducing means. An optical disk device comprising a gain value learning function for obtaining a set value of a means, and setting the obtained set value to the gain setting means. 2. The apparatus according to claim 1, further comprising a temperature detector for detecting an internal temperature of the optical disk device, wherein the gain value learning is performed when the temperature detected by the temperature detector changes by a predetermined value. 2. The optical disc device according to 1. 3. An apparatus for controlling the amplitude of a reproduced signal, comprising: an amplifier circuit; gain setting means for setting a gain of the amplifier circuit; and a storage element storing device individual information. An optical disc, wherein the gain value learning is performed, and a gain setting value obtained by the gain value learning and the device individual information of the device are recorded in a specific area on the optical disc. apparatus. 4. A temperature detecting means for detecting an internal temperature of the optical disk device, wherein the gain value learning is performed in accordance with a change in the temperature detected by the temperature detecting means, and a gain obtained by the gain value learning is provided. 4. The optical disk device according to claim 1, wherein a set value, a temperature at that time, and the device individual information are recorded in a specific area on the optical disk. 5. A device for reading a gain setting value and device individual information present in a specific area on an optical disk, and collating the device individual information with its own device individual information. 4. The optical disk device according to claim 3, wherein when the values match, the read gain setting value is set in the gain setting means. 6. A comparison device for reading a gain set value, device individual information, and temperature information existing in a specific area on an optical disc, and comparing the device individual information with its own device individual information, and a temperature detecting device. Wherein, when the device individual information matches and the temperature detected by the temperature detecting means matches the temperature information, the read gain setting value is set in the gain setting means. The optical disk device according to claim 3 or 4. 7. An apparatus comprising an amplitude control means for a reproduced signal, said amplitude control means comprising an amplifier circuit and a gain setting means for setting a gain of said amplifier circuit, and further comprising a storage element. Reading the disk individual information described in the specific area, performing the gain value learning, and storing the gain set value obtained by the gain value learning and the disk individual information in the storage element. Optical disk device. 8. An optical disk apparatus comprising: a temperature detecting means for detecting an internal temperature of the optical disk device, wherein the gain value learning is performed in accordance with a change in the temperature detected by the temperature detecting means, and a gain obtained by the gain value learning is provided. 8. The optical disk device according to claim 1, wherein a set value, a temperature at that time, and the disk individual information are stored in the storage element. 9. A discriminating means for reading disc individual information described in a specific area of the optical disc, and collating the disc individual information with disc individual information stored in the storage element, and when the collation results match, 8. The optical disk device according to claim 7, wherein when the gain setting value exists, the gain setting value is set in the gain setting means. 10. A disc reading device which reads disc individual information written in a specific area of an optical disc, and compares the disc individual information with disc individual information stored in the storage element, and a temperature detecting means. When the individual information matches, and the temperature detected by the temperature detecting means matches the temperature information stored in the storage element, the read gain setting value is set in the gain setting means. The optical disk device according to claim 7 or 8, wherein