JP2000215610A - Optical disk apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust the amplitude of reproduced signals to a target amplitude in an optical disk recording/reproducing apparatus regardless of the variations of disks and the apparatus and an operation state of the apparatus. SOLUTION: An output signal of a pickup 2 is changed in amplitude by an attenuator 7 and output as a reproduced signal. The amplitude of the reproduced signal is detected by an envelope detect circuit 3. The reproduced signal is input to an attenuator control part 13 through a low-pass filter 9 and an averaging process part 10. The attenuator control part 13 sets the attenuator 7 so that the reproduced signal has a target amplitude. In the optical disk apparatus of this constitution, characteristics of the low-pass filter 9 and an average number of times of the averaging process part 10 are changed in accordance with the operation of a tracking control part 20 and a rotational speed of a motor 4, and also a switch 11 is turned off in accordance with an output of an address part detect circuit 16, whereby the amplitude of the reproduced signal can be adjusted without being influenced by the disk types and an operation state of the apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a function for adjusting the amplitude of a reproduced signal used in an optical disk recording / reproducing apparatus.

[0002]

2. Description of the Related Art In recent years, as an optical disk recording / reproducing apparatus, an apparatus for recording / reproducing various kinds of optical disks having different reflectances has been developed. In order to reproduce optical disks having different reflectivities, it is necessary to adjust the amplitude of a reproduced signal for each disk having a different reflectivity. In the related art, there is known a method of detecting the amplitude of a reproduction signal amplitude and controlling an amplifier having a variable gain so that the amplitude becomes a target value (for example, Japanese Patent Application Laid-Open No. Hei 9-115142).

FIG. 19 shows a general example of a conventional optical disk apparatus having a function of adjusting the amplitude of a reproduced signal. Information recorded on the optical disk 1 is read by the pickup unit 2 and converted into an electric signal. The output of the pickup unit 2 is input to an amplifier 191 whose gain can be variably set, and the signal amplified by the amplifier 191 is output as a reproduction signal to a circuit for restoring and reproducing data recorded on a disc not shown in FIG. And output to the envelope detection circuit 3. The envelope detection circuit 3 detects and outputs the amplitude of the signal input from the amplifier 191. The output of the envelope detection circuit 3 is output to the control circuit 192. The control circuit 192 compares a target value preset inside with a signal input from the envelope detection circuit 3,
The gain of the amplifier 191 is adjusted so that the difference disappears. The amplifier 191 whose gain has been adjusted outputs a reproduced signal with a target amplitude.

[0004]

In the prior art, when the tracking control is not operating, every time the light beam crosses the track, the light beam passes through a portion where data is not recorded between the tracks. The envelope of the reproduction signal fluctuated greatly, and it was not possible to output the reproduction signal of the target amplitude. Also, when the rotation speed of the disk is increased, the band of the reproduction signal is increased accordingly, while the band of the envelope detection circuit of the reproduction signal is not infinite but is actually limited, so that the output of the envelope detection circuit is limited. The amplitude of the actual reproduced signal may be different, and the amplitude of the reproduced signal cannot be adjusted to the target value. Further, the output of the envelope detection circuit changes in accordance with the offset of the circuit or the scratch or defect of the disk, so that there is a problem that an error occurs in the adjustment result. Therefore, in the related art, the operation state of the apparatus when adjusting the amplitude of the reproduction signal is limited. However, in recent years, an optical disk device for reproducing a plurality of types of disks in the same device has been developed, and it has become necessary to be able to adjust the amplitude of a reproduced signal without depending on the operation state of the device. For example, a specific description will be given using a procedure for performing focus position adjustment for moving a focus lens to an optimum position. The focus position adjustment is a control for finding the optimum focus position so that the amplitude of the reproduction signal is maximized. However, since the maximum amplitude of the reproduction signal differs for each disc type, the input range of the output signal of the envelope detection circuit is increased. Need to be taken. On the other hand, the resolution of the circuit that handles input values is limited,
The accuracy of the input signal decreases, and as a result, the adjustment accuracy of the focus position adjustment deteriorates. To increase the accuracy of the focus position adjustment, before adjusting the focus position,
It is necessary to adjust the amplitude of the reproduced signal to a substantially constant amplitude irrespective of the type of the disk to reduce the input range of the output signal of the envelope detection circuit. Here, if the focus position is not adjusted, a tracking error signal used for tracking control may not be output correctly, and tracking control may not be performed. Therefore, it is necessary to adjust the focus position before performing the tracking control. However, as described above, in the related art, it is necessary to perform tracking control in order to adjust the amplitude of the reproduction signal, and as a result, the adjustment accuracy of the focus position adjustment cannot be increased. In order to solve this problem, it is sufficient that the amplitude of the reproduced signal can be adjusted before the tracking control is performed. In the above example, the operation state of the tracking control has been described. However, it is desirable that the amplitude of the reproduction signal can be adjusted without being limited to the operation state of the apparatus such as the rotation speed of the disk. The present invention
An object of the present invention is to adjust the amplitude of a reproduction signal without being affected by the operation state of the device.

In a rewritable disk or the like, there is an area where data is not recorded (unrecorded portion), and no reproduced signal is output. Therefore, in the related art, if the amplitude of the reproduction signal is adjusted when the light beam is positioned at the unrecorded portion, the output of the envelope detection circuit does not change even if the gain is changed. There was a problem that you can not. SUMMARY OF THE INVENTION It is an object of the present invention to detect an unrecorded portion and reliably adjust the amplitude of a reproduced signal when a light beam is positioned at a recorded portion of a disk.

When adjusting the amplitude of a reproduction signal in a disk having an area (address section) in which an address for identifying data is recorded, the amplitude of the reproduction signal is adjusted when the light beam is positioned at the address section. Because of the difference, the output of the envelope detection circuit fluctuates, so that the conventional technique has a problem that an adjustment error occurs. The present invention
An object of the present invention is to adjust the amplitude of a reproduction signal without being affected by an address portion in a disk having an address portion.

[0007]

In order to solve the above-mentioned problems, the present invention provides a low-pass filter and an averaging section for averaging and outputting an input signal as means for inputting an output signal of an envelope detection circuit. In accordance with the operation state of the device such as the operation state of the tracking servo and the rotation speed of the spindle motor, conditions such as the pass characteristics of the low-pass filter and the average number of times of the averaging unit can be variably set, and The adjustment target value can be set variably.

In order to prevent the reproduction signal amplitude from being erroneously adjusted when the light beam is located in the unrecorded portion, a threshold value is provided for the output of the envelope detection circuit. Without executing, after the position of the light beam is changed by a certain distance, the output of the envelope detection circuit is again compared with the threshold value, and the operation of moving the light beam until the output value becomes equal to or more than the threshold value is repeated, so that the recording unit is securely performed. This makes it possible to adjust the amplitude of the reproduction signal.

Further, in order to adjust the amplitude of the reproduced signal in the disk having the address portion without being affected by the fluctuation of the envelope signal in the address portion, the address portion is detected and the envelope signal is detected during the period in which the address portion is detected. Output is stopped.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention provides a reproducing means for reproducing information recorded on a disc,
An amplification unit that can variably set a gain for amplifying an output of the reproduction unit, an amplitude detection unit that detects an amplitude from an output of the amplification unit, and a smoothing processing unit that smoothes an output of the amplitude detection unit, A gain setting unit that sets the gain of the amplifying unit according to the output of the smoothing processing unit and sets the output of the amplifying unit to a predetermined amplitude, and the gain setting unit according to the operation state of the device. An optical disk device characterized by changing the smoothing process, and has an effect that the operation state of the device when adjusting the amplitude is not limited.

[0011] The invention described in claim 2 of the present invention is claim 1.
In the optical disc device described, the gain setting unit sets the output of the amplification unit to a predetermined amplitude by setting the gain of the amplification unit so that the output of the smoothing processing unit becomes a predetermined target value. This has the effect that the operation state of the apparatus when adjusting the amplitude of the reproduction signal is not limited.

The invention according to claim 3 of the present invention is the invention according to claim 2.
In the optical disk device described above, the target value is changed in accordance with the operation state of the apparatus, and has the effect of reducing the alignment error generated in accordance with the operation state of the apparatus when adjusting the amplitude of the reproduction signal.

The invention according to claim 4 of the present invention is the invention according to claim 3.
In the optical disc device described above, the target value is changed when the tracking control for causing the reproducing means to follow the track on the disk is operating and when it is not operating. Is not limited.

[0014] The invention according to claim 5 of the present invention is the invention according to claim 4.
In the optical disk device described above, when the tracking control is not operating, the target value is set lower than when the tracking control is operating, and the tracking control state when adjusting the amplitude of the reproduction signal is not limited. Have.

The invention according to claim 6 of the present invention is the invention according to claim 1.
In the optical disc device described above, the smoothing processing of the smoothing processing unit is changed between when the tracking control for causing the reproducing means to follow the track on the disk is operating and when it is not operating. This has the effect that the tracking control state at the time of performing is not limited.

The invention according to claim 7 of the present invention is directed to claim 4
In the optical disc device according to the fifth and fifth aspects, the gain setting unit is operated to set the gain of the amplification unit when the tracking control is not operating, and then the gain setting unit is operated when the tracking control is operating and the gain of the amplification unit is again adjusted. Set the output of the width detector to the amplitude necessary to improve the adjustment accuracy of the focus position adjustment when the tracking control is not operating, and it is recorded on the disk when the tracking control is operating This has the effect that the amplitude can be adjusted to the amplitude required to reproduce the information.

The invention according to claim 8 of the present invention is directed to claim 7
The optical disc device according to the above, further comprising a setting storage means for storing a setting value of the amplifying unit, wherein the setting value of the amplifying unit when the tracking control is not operating is stored in the storage means, and the tracking control is operated. When the tracking control is in operation, the settable range of the gain of the amplifying unit is limited to a range that is increased or decreased by a fixed amount with respect to the set value stored in the setting storage unit. This has the effect that the time for adjusting the amplitude can be reduced.

According to the ninth aspect of the present invention, an eighth aspect is provided.
In the optical disc device described above, the output of the amplitude detector is changed to a target value by changing the gain from the lowest settable range of the amplifying section to the largest setting. Has the effect of shortening the time for adjusting the amplitude of.

According to a tenth aspect of the present invention, there is provided the optical disk apparatus according to the first aspect, further comprising a defect detecting section for detecting scratches, dust adhesion, or defects on the disk. Stops the output of the amplitude detector when dust is attached or a defect is detected, so that the amplitude of the playback signal can be adjusted without affecting the output of the amplitude detector due to disc scratches, dust, or defects. Having.

According to an eleventh aspect of the present invention, in the optical disk device of the first aspect, there is provided an off-track detecting section for detecting that the reproducing means has deviated from the track being scanned. The output of the amplitude detection unit is stopped when it is detected that the reproducing means has come off the track under investigation. This has the effect that the amplitude of the signal can be adjusted.

According to a twelfth aspect of the present invention, in the optical disk device according to the tenth aspect, when the tracking control is not operating, the operation of the defect detection unit is stopped. It has the effect of preventing the effect of the detection unit malfunctioning.

According to a thirteenth aspect of the present invention, in the optical disk device according to the eleventh aspect, the operation of the off-track detecting unit is stopped when the tracking control is not operating. This has the effect of preventing the effect of the off-track section malfunctioning.

According to a fourteenth aspect of the present invention, there is provided the optical disk apparatus according to the first aspect, further comprising a period detector for detecting a rotation period of the disk, and a smoothing processing unit in accordance with an output of the period detector. It changes the smoothing process, and has the effect of removing the effect of the fluctuation of the output of the amplitude detector changing according to the disk rotation cycle.

According to a fifteenth aspect of the present invention, in the optical disk device according to the fourteenth aspect, the smoothing process is performed over a period equal to or longer than the disk rotation time detected by the period detector. It has the effect of removing the effect that the fluctuations change due to disk eccentricity.

According to a sixteenth aspect of the present invention, in the optical disk device according to the third aspect, there is provided a period detector for detecting a rotation period of the disk, and a target value is changed according to an output of the period detector. When a signal having a frequency exceeding the operating band of the amplitude detector is input from the reproducing means in accordance with the rotation cycle of the disk, a target value is set in accordance with a decrease in the output of the amplitude detector. This has the effect that the amplitude of the reproduction signal can be adjusted without limiting the disk rotation cycle.

According to a seventeenth aspect of the present invention, in the optical disk device of the sixteenth aspect, the target value is reduced as the output of the period detector decreases. When a signal with a frequency exceeding the operating band of the amplitude detector is input, the target value is set lower as the output from the amplitude detector decreases, so that the disk rotation cycle is not limited and the amplitude of the reproduced signal is not limited. It has the effect that adjustment can be performed.

According to an eighteenth aspect of the present invention, in the optical disk device according to the first aspect, the smoothing processing unit includes a low-pass filter capable of changing a cutoff characteristic. Can be easily configured.

According to a nineteenth aspect of the present invention, in the optical disk device according to the first aspect, the smoothing processing of the smoothing processing unit is an averaging process in which the number of additions can be set from the outside. Can be easily configured.

According to a twentieth aspect of the present invention, in the optical disk device according to the nineteenth aspect, when tracking control is not operating, the number of additions of the averaging process is increased compared to when tracking control is operating. This has the effect of smoothing the fluctuation of the output of the amplitude detector, which becomes larger when the tracking control is not operating than when the tracking control is operating.

According to a twenty-first aspect of the present invention, in the optical disk device according to the first aspect, the reproducing means includes a light source for irradiating the disk with a light beam and a detector for receiving light reflected or transmitted from the disk. Offset storage means for storing the output value of the amplitude detection unit when the light source is not emitting light, the value stored in the offset storage means from the output value of the amplitude detection unit when the light source is emitting light The subtraction has the effect of removing the influence of the offset generated by the amplitude detector and different for each device.

According to a twenty-second aspect of the present invention, in the optical disk apparatus, the reproducing means for reproducing the information recorded on the disk, the moving means for moving the reproducing means in the radial direction of the disk, and the reproducing means are not provided. An unrecorded portion detection unit that detects that the recording unit is located, an amplification unit that can variably set a gain for amplifying an output of the reproduction unit, an amplitude detection unit that detects an amplitude from an output of the amplification unit, A gain setting unit that sets a gain of the amplifying unit in accordance with an output of the amplitude detecting unit and sets an output of the amplifying unit to a predetermined amplitude; The reproducing means is moved by the moving means to a position where the reproduction means is not detected when it is detected that the reproduction signal amplitude is erroneously adjusted in an unrecorded portion.

According to a twenty-third aspect of the present invention, in the optical disk device according to the twenty-second aspect, the unrecorded portion detecting means is such that the reproducing means is located in the unrecorded portion when the output of the amplitude detecting portion is equal to or less than a predetermined value. This has the effect of easily configuring the unrecorded portion detection section.

According to a twenty-fourth aspect of the present invention, there is provided a reproducing means for reproducing information recorded on a disk in an optical disk device, an amplifying section capable of variably setting a gain for amplifying an output of the reproducing means; An amplitude detection unit that detects an amplitude from an output of the unit, a gain setting unit that sets a gain of the amplification unit according to an output of the amplitude detection unit and sets an output of the amplification unit to a predetermined amplitude, An address section detecting section for detecting that the reproducing section is located at an address section in which an address for identifying an area is recorded; and detecting that the reproducing section is located at the address section. When the means detects the output, the output of the amplitude detector is stopped, and the effect of removing the influence of the fluctuation of the output of the amplitude detector in the address section is provided.

According to a twenty-fifth aspect of the present invention, in the optical disk device of the twenty-fourth aspect, when the tracking control is not operating, the operation of the address portion detecting means is stopped, and the tracking control operation is not performed. It has an effect of preventing the influence of the address detecting means from sometimes malfunctioning.

(Embodiment 1) FIG. 1 is a block diagram showing an optical disk apparatus according to a first embodiment of the present invention. In FIG. 1, reference numeral 2 denotes a pickup unit which converts reflected light of a light beam applied to the disk 1 into an electric signal and outputs the electric signal. Reference numeral 4 denotes a spindle motor for rotating the disk 1; Is a traverse motor that can move in the radial direction of the disk 1 and that drives the traverse 5 in the radial direction of the disk 1 in response to a traverse control signal from a traverse control unit 19 that performs traverse control and search control.

The output signal of the pickup section 2 is an attenuator 7 whose attenuation rate can be switched in multiple stages.
The attenuator 7 changes the attenuation rate of the input signal according to the set value from the attenuator set value control unit 13 and then amplifies the signal at a fixed amplification rate and outputs the amplified signal. The signal output from the attenuator 7 is detected by the envelope detection circuit 3 and output. The output signal of the envelope detection circuit 3 is input to the A / D converter 8. A
The output of the / D converter 8 is input to a low-pass filter 9 composed of a first-order lag element.

The output of the low-pass filter 9 is connected to a switch 11
Is input to the averaging processing unit 10 via an input terminal, and the input to the averaging processing unit 10 can be switched ON / OFF by input to the control terminal of the switch 11. Details of the control signal of the switch 11 will be described later.

The averaging unit 10 receives data indicating the number of times of averaging for performing the averaging process from the attenuator set value control unit 13. The averaging unit 10 adds the input values every 140 μs, and counts the number of additions. The addition is repeated until the added count reaches the average number set by the attenuator set value controller 13. When the counted number reaches the average number, a value obtained by dividing the added sum by the average number is output as an average value. Averaging unit 10
Indicates that when the switch 11 is turned off during the addition processing, the processing of adding the value added immediately before
Repeat until N.

The output of the averaging section 10 is input to the attenuator set value control section 13.

The attenuator set value control section 13 sets the attenuator 7 so that the input value becomes the adjustment target value set in the attenuator set value control section 13. The detailed operation of the attenuator set value control unit 13 will be described later with reference to the flowchart of FIG.

An output signal from the pickup unit 2 is scanned by a defect detection circuit 14 for detecting that the light beam is positioned on a defect which is a scratch or dust on the disk, and when the light beam follows a track. The signal is also input to an off-track detection circuit 15 for detecting that the track is coming off the middle track. The defect detection circuit 14 determines that the light beam is on the defect when the amplitude of the output signal of the pickup unit 2 becomes equal to or less than a predetermined value, and sets the signal to an “H” level otherwise. Is output. The output signal is input to the control terminal of the switch 11 through the OR circuit A and the AND circuit B.

The off-track detection circuit 15 outputs an "L" signal when the light beam is positioned on the track of the disk by using the output signal from the pickup unit 2,
This is a circuit that outputs an H signal when a track goes off track.
The operation principle of the off-track detection circuit 15 will be described later. The output signal is input to the control terminal of the switch 11 through the OR circuit A and the AND circuit B.

Reference numeral 16 denotes an address part detection circuit for detecting an area in which an output signal of the pickup part 2 is inputted and which records an address for identifying data recorded on a disk or recorded data. It outputs 'H' when passing through an area where an address is recorded, and outputs 'L' when passing through an area where data is recorded. The operation of the address section detection circuit 16 will also be described later. The output signal is input to the control terminal of the switch 11 through the OR circuit A and the AND circuit B.

The tracking control section 20 is a control block for performing a tracking servo for causing a light beam to follow a track formed on the disk 1. Although the description of the specific configuration and operation of the tracking control is omitted, the tracking control unit 20 operates when the tracking servo operates and the light beam follows the track.
It outputs a binary signal that is H ', otherwise' L '.
The output of the tracking control unit 20 is input to the AND circuit B. It is also input to the attenuator set value control unit 13.

The OR circuit A is a defect detection circuit 1
4 and the output signal of the off-track detection circuit 15 and the output signal of the address part detection circuit 16 are ORed and output to one input terminal of the logical circuit B. AND circuit B
Is the output signal of the OR circuit A and the tracking control unit 20
And outputs a signal to the control terminal of the switch 11 by taking the logical product of the output signals.

The control terminal of the switch 11 is "H".
The switch is turned off when an input of “L” is received, and the switch is turned on when an input of “L” is received. The switching operation of the switch 11 will be described with reference to the table shown in FIG. Switch 1
1 is always ON when the tracking control unit 20 is not performing the tracking control operation and outputting the L signal. When the tracking control unit 20 operates and the light beam follows the track, the defect detection circuit 14
And off-track detection circuit 15 and address section detection circuit 16
Switch 11 becomes "H"
Becomes OFF.

The spindle motor 4 is provided with an FG circuit 17 for generating 24 pulses per rotation, and its output is input to a cycle counter 18 for counting the cycle of the pulse. The cycle counter 18 counts the time of one cycle of the input pulse using a clock generated internally, and counts the count value to the attenuator set value control unit 13.
Output to The operation of the attenuator setting control unit 13 using the output value of the cycle counter 18 will be described later with reference to FIG.

Reference numeral 12 denotes a laser control unit which is mounted on the pickup unit 2 and controls the emission power of the semiconductor laser that emits a light beam. Although the components and operation of the laser control unit 12 are omitted, a binary signal that outputs “H” when the laser is emitting and outputs “L” when the laser is not emitting is output. The output of the laser controller 12 is input to the attenuator set value controller 13. The operation of the attenuator set value control unit 13 using the output signal of the laser control unit 12 will also be described later with reference to FIG.

The traverse controller 19 receives a control signal for instructing the traverse from the attenuator set value controller 13 and information on the traverse movement distance and the movement direction. Although the description of the specific configuration and operation of the traverse control unit 19 is omitted, the attenuator set value control unit 1
When the traverse 5 is received from the traverse 5, the traverse 5 is driven and moved in the moving direction set by the attenuator set value control unit 13 by a distance corresponding to the moving distance set value.

Next, the function of each part of the components in FIG. 1 will be described in detail.

The configuration of the attenuator 7 will be described. In order to simplify the explanation, first, an attenuator having a configuration that can be set in 2 bits and can switch the attenuation rate in four steps is shown in FIG.
This will be described with reference to FIG. In FIG. 3, the attenuator value setting unit 31 receives a set value in 2 bits from the outside, and sets four switches SW in the attenuator unit 32 according to the set value.
A signal having two values of 'H' and 'L' is output to a control terminal for performing an ON / OFF switching operation of 1 to SW4. Switches SW1 to SW4 are turned on when receiving "H" input
Becomes The attenuator section 32 includes a resistor R1
To R4 are connected, and one side of the resistor R1 is connected to a switch S
W1 is connected to the input terminal to the attenuator section 32, and one side of the resistor R4 is grounded. The contacts between the resistors are connected to switches SW2, SW3, and SW4, respectively, and the other terminal of each switch is connected to the input terminal of the amplifier 33. The attenuator unit 32 includes a switch SW
In response to the switching operation of 1 to SW4, a signal input from the outside is divided and output to the amplifier 33. Resistance R1 to R4
Are set equal. The amplifier 33 amplifies the input signal with a double amplification factor and outputs the amplified signal. The operation of the components in FIG. 3 will be described with reference to FIG. When the set value input to the attenuator value setting unit 31 is 0, SW4 is set to O
N and the other SW1, SW2, and SW3 are turned off. At this time, the input signal to the attenuator unit 32 is R4
/ (R1 + R2 + R3 + R4) = 1/4 is output after being divided by the amplifier 33 and doubled by the amplifier 33 as a result. Attenuator value setting unit 31
When the set value input to the switch is 1, SW3 is turned on and the other switches SW1, SW2, and SW4 are turned off. At this time, the input signal to the attenuator section 32 is a resistor R4 + R3
/ (R1 + R2 + R3 + R4) = 1/2 is output after being divided by the amplifier 33. As a result, the output is multiplied by one and output. When the set value input to the attenuator value setting unit 31 is 2, SW2 is turned on, and the other SW1, SW3, and SW4 are turned off. At this time, the input signal to the attenuator section 32 is a resistor R4 + R3 + R
The output voltage is divided into 2 / (R1 + R2 + R3 + R4) = 3/4 and output by the amplifier 33, so that it is output as 3/2 times. Attenuator value setting unit 3
When the set value input to 1 is 3, SW1 is turned on, and the other SW2, SW3, and SW4 are turned off. At this time, the input signal to the attenuator section 32 is output without being divided, and is output by being doubled by the amplifier 33.
Accordingly, the attenuator 7 amplifies the input signal in a range of 1/2 to 2 times and outputs the amplified signal in four stages.

The attenuator 7 according to the first embodiment has a configuration in which 4-bits can be actually set, and 16 stages of amplification rates can be set. FIG. 5 shows the relationship between the set value of the attenuator 7 and the amplification factor. When the setting value of the attenuator 7 is 0, the output is multiplied by 1/4 and when it is 15, the output is multiplied by 4 and output.

Next, FIG. 6 shows the configuration of the envelope detection circuit 3. Reference numeral 61 in FIG. 6 denotes an amplifier having a constant amplification factor, which amplifies an input signal by a factor of 12.5 and outputs the amplified signal. The signal amplified by the amplifier 61 is input to the clamp circuit 62. The clamp circuit 62 clamps the lower side of the amplitude of the input signal at 0 mV. The output of the clamp circuit 62 is input to the detection circuit 63. Detection circuit 63
Detects and outputs the peak voltage of the input signal with its lower side clamped. Therefore, the envelope detection circuit 3
Outputs a signal corresponding to the AC amplitude of the input signal. Actually, since the clamp circuit 62 is constituted by an analog circuit, the output thereof has a constant offset different for each device, and the clamp level does not become 0 mV. When adjusting the amplitude of the reproduction signal, it is necessary to remove the influence of this offset. Although specifically described with reference to FIG. 2, the output signal of the envelope detection circuit 3 was measured in a state where no signal was input to the envelope detection circuit 3, and the signal was subsequently input to the envelope detection circuit 3. At this time, a process of removing the measured offset from the output of the envelope detection circuit 3 is performed. In the following description, the offset amount generated by the clamp circuit 62 is 370 mV.

The A / D converter 8 converts an input signal of 0 V to 2.5 V into an 8-bit digital value and outputs it. 0 is output when the input is 0 V, and 255 is output when the input is 2.5 V.
Is output. Therefore, an input of about 10 mV is converted to a digital value of 1.

Next, the operation principle of the off-track detection circuit 15 will be briefly described.

Data is recorded on the tracks of the disk 1 in pits having a convex shape. When a light beam is irradiated on the track, a light diffraction phenomenon occurs due to the pits, and the amount of light reflected by the disk and received by the detector inside the pickup unit 2 decreases. Therefore, when the light beam is on the track where data is recorded, the output of the pickup unit 2 is at a low level when the light beam is passing through the pit, and is diffracted when the light beam is passing without the pit. This is a high level because no noise occurs. That is, modulation occurs due to the presence or absence of pits. However, when the light beam deviates from the track being scanned and is at a position where there is no pit row between the tracks, there is no modulation due to the presence or absence of the pit, and the output signal of the pickup unit 2 is DC.
Is output at a high level. FIG. 7A is a diagram schematically showing a cross section of the disk 1 cut in a direction perpendicular to the track and a direction in which the light beam crosses the track off the track being scanned. It is assumed that the light beam traverses the track at a constant speed in the direction of the arrow shown in FIG. (B) shows the waveform of the signal output from the pickup unit 2 in that case on the time axis. When the light beam is positioned on the track, modulation based on the presence or absence of pits is output from the pickup unit 2, and when the light beam is positioned between the tracks, a high level DC value is output from the pickup unit 2. Also, broken lines vertically written in the figure indicate time synchronization with respect to the figures (a) to (d). The off-track detection circuit 15 detects the lower level of the amplitude of the output signal of the pickup unit 2. (C)
3B shows a state in which the lower level of the output waveform of the pickup unit 2 is detected inside the off-track detection circuit 15. Then, the off-track detection circuit 15
Converts a voltage higher than a half level of the peak of the detected signal into a binary signal with “H” and a low voltage with “L” and outputs the binary signal. (D) shows the waveform of the binarized output signal of the off-track detection circuit 15. Therefore, the off-track detection circuit 15 outputs a signal that becomes “L” when the light beam is positioned on the track and becomes “H” when the light beam is off-track.

Next, the operation of the low-pass filter 9 will be described. After detecting the peak level of one cycle of the input signal in the envelope detection circuit 3, the output of the envelope detection circuit 3 decreases at a time constant unique to the detection circuit 63 until the peak level of one cycle that is subsequently input is detected. To go. FIG. 8 shows how the output of the envelope detection circuit 3 decreases with a constant time constant.
FIG. 8A shows the input signal to the envelope detection circuit 3 with the vertical axis representing the voltage and the horizontal axis representing the time axis. In FIG. ) Shows the synchronization of time with respect to the figure. (B) shows the waveform of the signal output by clamping the lower level of the signal shown in (a) by the clamp circuit 62, and (c) detects the signal shown in (b). The figure shows the waveform of a signal output by detecting the peak level of an input signal when input to the circuit 63. As shown in (c), after the detection circuit 63 detects the peak level of the signal shown in (b) at the timing of time t1, the output of the detection circuit 63 is constant until the next peak is detected at the timing of time t2. With the time constant of This decrease causes the output value of the envelope detection circuit 3 to fluctuate. The low-pass filter 9 is used for smoothing a fluctuation component generated due to the above cause. Here, the detection frequency of the peak level in the detection circuit 63, which is the frequency of the fluctuation component, will be described with reference to FIG. FIG. 9A schematically shows a state in which a light beam passes over a pit along a track along with the rotation of a disk, and FIG. 9B shows a vertical broken line in the figure. (A) As shown in FIG.
2 shows the waveform of the signal output from No. 2 with time on the horizontal axis and voltage on the vertical axis. As shown in (a) and (b), when a light beam is applied to a pit having a length equal to or longer than the spot diameter, the output of the clamp circuit 62 has a peak level. Therefore, the frequency of the fluctuation caused by the output decreasing at a constant time constant after detecting the peak in the detection circuit 63 depends on the recorded data, that is, the presence or absence of pits, and the speed at which the light beam scans the track. I do. In order to smooth the fluctuation component caused by the above-described cause, the cutoff frequency of the low-pass filter 9 is set to be equal to or lower than the minimum frequency of the fluctuation. For example, a case where a disc such as a CD is reproduced will be described. Pit length 11T,
When a light beam passes through a portion where a frame synchronization signal having a space length of 11T is recorded, the modulation frequency due to the presence or absence of pits becomes the lowest, and this frequency is about 200 kHz when the disk is rotating at a standard speed. Become. Here, in the low-pass filter 9 having a first-order lag element,
In the case where the fluctuation of the output signal of the envelope detection circuit 3 caused by the above-described cause is suppressed to 1/10, the filter may have a cutoff frequency of 20 kHz or less.

Next, the configuration of the cycle counter 18 will be described. The cycle counter 18 is a counter that receives an output pulse of the FG circuit 17 and counts an interval from a rising edge to a next rising edge by a clock generated internally. For example, the frequency of the internally generated clock is 3.0 MHz, and the disk is 210 rpm
Suppose that it is rotating at m. Since the FG circuit 17 outputs 24 pulses per rotation of the disk, the frequency of the input signal to the period counter 18 is 210 ÷ 60 × 24 = 84
Hz. At this time, the time from the rising edge to the input of the next rising edge is 1/84 = 11.9.
ms, so the output of the period counter 18 is 11.
9 ms × 3000 kHz = 35700.

Next, referring to FIG.
6 will be described. A data slice circuit 101 receives a signal from the pickup unit 2 and binarizes the input signal at a constant slice level. The output of the data slice circuit 101 is input to an address reading circuit 102 for identifying an address. Address reading circuit 102
Determines from the output of the data slice circuit 101 that the light beam is scanning an address for identifying the data recorded on the disk, and at the time when the address is identified, becomes 'H', and the light beam is A signal which becomes "L" when scanning data is sent to the address part gate signal generation circuit 1.
03 is output. Address part gate signal generation circuit 103
Has a built-in timer that counts from the falling edge of the input signal using the internally generated reference clock, and corresponds to the time corresponding to the time for the light beam to reach the area where the next address is recorded After the elapse, the signal becomes “H”, and thereafter, a signal that becomes “L” in synchronization with the address reading circuit 102 becoming “L” is output. Next, the operation of the address part detection circuit 16 will be described with reference to FIG. FIG. 11A schematically illustrates a state in which a light beam moves along a track due to rotation of a disk. The track is formed by equally dividing the sector unit, and an address for identifying data of the sector is recorded at the head of the sector (hereinafter, this area is called an address part, and data is recorded / reproduced). The area to be processed is referred to as a data section). The timing chart of the output of the address reading circuit 102 when the light beam is moving at a constant speed in the direction of the arrow shown in FIG. It is shown in (c). When the light beam is located at the address portion and the address is identified by the address reading circuit 102, the output signal of the address reading circuit 102 becomes "H" as shown in FIG. The address reading circuit 102 determines the position of the light beam on the track from the identified address, and outputs an “L” signal when the light beam reaches the data portion. The address part gate signal generation circuit 103 uses a built-in timer,
After a lapse of a predetermined time from the time when the input signal becomes “L”, a signal that becomes “H” is output. The output of the address section gate signal generation circuit 103 is the address read circuit 102
Becomes 'L' simultaneously with the output of 'L'. The predetermined time measured by the timer of the address part gate signal generation circuit 103 is set so that the light beam is located just after the predetermined time at the head of the next address part following the light beam. Accordingly, as shown in FIG. 11C, the output of the address section gate signal generation circuit 103 becomes “H” during the period when the light beam is located on the address section.

Next, a function realized by the components described above operating in cooperation will be described with reference to FIG. The attenuator set value control unit 13 is composed of a processor such as a microcomputer having an arithmetic unit, a plurality of memories, and an input / output device. FIG. 2 is a flowchart showing the operation of the attenuator set value control unit 13.

Here, in order to explain various functions exerted when adjusting the amplitude of the reproduction signal of a plurality of types of disks having different characteristics, a disk having a sector constituted by a data portion and an address portion is described. Assuming you want to play,
The function of the attenuator set value control unit 13 will be described in time series. The function of the attenuator set value control unit 13 is that the laser is not emitting, the light beam is in an area where no data is recorded, the tracking servo is not operating, and the tracking servo is operating. Time is divided.

First, the operation when the laser does not emit light will be described. Prior to the processing of FIG. 2, it is assumed that the disk 1 is rotated at a predetermined speed by the spindle motor 4, the semiconductor laser is not emitting light, and the laser control unit 12 outputs an "L" signal. At this time, the tracking servo is not operating, and the tracking control unit 20 outputs an “L” signal, and the AND circuit B
Output "L", the switch 11 is always in the ON state. Since the offset generated by the clamp circuit 62 differs for each device, if the amplitude of the reproduced signal is adjusted as it is, an error will occur due to the offset. Therefore, the offset generated by the clamp circuit 62 is measured and corrected. This processing is performed by using that the value output from the A / D converter 8 indicates the offset of the clamp circuit 62 because the signal output from the pickup unit 2 becomes 0 when the laser does not emit light. Hereinafter, the offset of the clamp circuit 62, which differs from device to device, will be described as 370 mV for simplification of the description.

First, since the laser control unit 12 outputs "L", the process branches from the A0 processing unit to the B1 processing unit. The offset output from the envelope detection circuit 3 is DC, which is output as it is through the low-pass filter 9. Since there is no change in the output of the low-pass filter 9, the B1 processing unit sets the average number of times of the averaging processing unit 10 to 1. The averaging unit 10 receives the value from the low-pass filter 9 and outputs the value as it is. Since the offset output from the envelope detection circuit 3 is 370 mV and the input of the A / D converter 8 outputs a 1-bit value per about 10 mV, 37 is output in the case of a decimal number. In the subsequent B2 processing unit, the input value 37 is stored in the memory MEM-OFS for storing the offset, and the processing ends. Hereinafter, in the flowchart and the description thereof, the value stored in the MEM-OFS is represented by X, and in the specific description of the numerical value, 37 is M.
The description will be made assuming that the data is stored in the EM-OFS.

Next, the operation when the light beam is located in an area on the disk where no data is recorded will be described. In the following description, the fact that the light beam is located in an area composed of tracks on which data has not been recorded will be referred to as being in an unrecorded area, and that the light beam will be located in the area composed of tracks on which data is recorded. Is referred to as being in the recording unit.

The disk 1 is rotated at a predetermined speed by a spindle motor 4, a semiconductor laser emits light at a predetermined power by a laser control unit 12, and a light beam is focused on the disk 1 by a focus control means (not shown). It is assumed that it is controlled so that Further, it is assumed that the tracking servo operation is not performed by the tracking control unit 20 and the light beam is in an unrecorded portion of the disk. At this time, the laser control unit 12 outputs an “H” signal, and the tracking control unit 20 outputs an “L” signal. The switch 11 is always on because the AND circuit B outputs “L”. Further, X = 37 is stored in the memory MEM-OFS for storing the circuit offset generated by the envelope detection circuit 3.

When the light beam is in the unrecorded portion of the disk, there is no modulation due to the presence or absence of pits. Further, since the tracking servo operation is not performed, the light beam crosses the groove provided for recording data, and the output of the pickup unit 2 fluctuates between the grooves. However, this variation is clamped by the clamp circuit 62, and the clamp circuit 62 outputs a substantially constant DC value. FIG. 12A shows the output waveform of the pickup section 2 which fluctuates when the light beam crosses the groove, and FIG. 12B shows the output waveform of the clamp circuit 62 which is output simultaneously with FIG. As shown in (b), when there is no modulation due to the presence or absence of a pit, the output of the clamp circuit 62 has a substantially constant DC value. Therefore, if the amplitude of the reproduction signal is to be adjusted when the light beam is in the unrecorded portion of the disk, the output of the clamp circuit 62 is always at the clamp level. I cannot get the signal output I have. For this reason,
When the light beam is in the unrecorded portion of the disc, the light beam is moved to the recorded portion of the disc by performing the processing described below. The determination that the light beam is in the unrecorded portion of the disk is performed by utilizing the fact that the output of the clamp circuit 62 is at the clamp level.

Hereinafter, this processing will be described with reference to FIG.

First, since the output of the laser control unit 12 is "H" in the A0 processing unit, the flow branches to the A1 processing unit. The A1 processing unit performs the initial setting of the attenuator 7. As a set value to be initialized, a value stored in a memory MEM-ATEND described later is used. Here, when the amplitude adjustment of the reproduction signal has not been performed at all, it is assumed that the MEM-ATEND stores, as a fixed set value, a set value at which the amplification factor of the attenuator 7 is doubled. Therefore, a value at which the amplification factor is doubled is set in the attenuator 7. Also, a memory MEM-CNT described later is set to 0. Then, the A2 processing unit sets the average number of times in the averaging processing unit 10. When the light beam is in the unrecorded portion of the disk, the output of the clamp circuit 62 is DC and does not change. Therefore, it is not necessary to increase the average number of times to determine whether the light beam is in the unrecorded portion. However, in order to avoid erroneous determination due to the intrusion of disturbance such as noise, the average number is set to about 10 times. In the subsequent A3 processing unit, the value X = 37 stored in the MEM-OFS to remove the offset generated by the clamp circuit 62 from the output value of the averaging processing unit 10.
Is performed to obtain a result Y. When the light beam is in the unrecorded portion of the disc, the averaging unit 10 outputs 37 for the offset of the clamp circuit 62.
Y becomes 37-37 = 0. The A4 processing unit compares the value Y with a threshold value x, for example, 2 for detecting an unrecorded portion. Since the value Y is 0, it is smaller than the threshold value x = 2, so that the process proceeds to the C1 processing unit. The C1 processing unit adds 1 to the memory MEM-CNT for counting the number of times that it is determined whether the light beam is in the unrecorded part of the disk. In the following C2 processing unit,
It is determined whether or not MEM-CNT is a specific value y, for example, 5 or less, and the process branches. The meaning of y in the C2 processing unit will be described later. The process moves to the C3 processing unit assuming that MEM-CNT is 5 or less. The C3 processing unit outputs a value indicating the moving direction and the moving distance and a traverse movement command signal to the traverse control unit 19 so as to move the traverse 5 by a specific distance, for example, 1 cm in the outer circumferential direction. The traverse control unit 19 receives the traverse movement command signal from the attenuator set value control unit 13, moves the traverse 5 by 1 cm in the outer circumferential direction, and repeats the A4 process again. The C2 processing unit is for determining whether the traverse 5 has moved to the outermost position. More specifically, the number of times the traverse 5 has moved by 1 cm to the MEM-CNT is shown, and the value y indicates the upper limit of the number of times the traverse 5 can be moved. Diameter 12
In the optical disc of cm, the distance that the traverse 5 can move from the innermost position to the outermost position is about 5 cm.

Since the traverse 5 has moved by 5 cm when the MEM-CNT reaches 5 in the C1 processing unit, it means that the traverse 5 has moved to the outermost position. If the value Y does not become equal to or more than x when the traverse 5 is moved from the innermost circumference to the outermost circumference, it means that the traverse 5 has failed to move the light beam to the recording unit of the disk. Terminates as abnormal. When the traverse 5 moves to the recording portion of the disk, the amplification factor of the attenuator 7 is set to be twice. 125mV multiplied by 12.5
Is input to the A / D converter 8. As described above, since the envelope detection circuit 3 has an offset,
By inputting mV + 370 mV = 495 mV to the A / D converter 8, the output of the averaging unit 10 becomes 49. Therefore, the value Y is 49−37 = 12, and the threshold value x is 2
At this time, since the value Y is determined to be equal to or more than x in the A4 processing unit, the processing shifts to the A5 processing unit. Subsequent processing in the A5 processing section and thereafter is processing for adjusting the amplitude of the reproduced signal by operating the set value of the attenuator 7.

The light beam was moved to the recording portion of the disk by performing the above-described processing. Subsequent processing is exactly the same as the processing when the light beam is located at the recording portion of the disk and the tracking servo operation is not performed. Therefore, assuming that the tracking servo operation is not performed, the processing after the A5 processing unit is assumed. The processing will be described. Each component in FIG. 1 operates in the same manner as when the light beam is in an unrecorded portion of the disk.

In general, there is an optical disc apparatus equipped with a focus position adjusting function for changing a focus control target position so as to maximize the amplitude of a reproduction signal from a disc in order to stabilize focus servo. The output of the envelope detection circuit 3 is used to determine the amplitude of the reproduction signal in the focus position adjustment function. Here, the amplitude of the reproduction signal output from the pickup unit 2 differs depending on the disc type, and therefore, the maximum value of the amplitude of the reproduction signal also differs. Here, in order to perform the focus position adjustment in a device configured to be able to reproduce a plurality of types of disks in the same optical disk device, it is necessary to input a circuit for inputting an output signal of the envelope detection circuit 3 in the focus position adjustment function. It becomes necessary to increase the possible range. However, since the resolution of the circuit that handles the input value is limited, the accuracy of the input value is reduced as a result, and the adjustment accuracy of the focus position adjustment is reduced. In order to avoid this problem and increase the adjustment accuracy of the focus position adjustment, it is necessary to reduce the inputtable range of the circuit. Therefore, before performing the focus position adjustment, the amplitude of the reproduction signal is adjusted to affect the disc type. And the amplitude of the reproduced signal is made substantially the same. Here, if the focus position is not adjusted, the tracking error signal used for the tracking control may not be output correctly, and thus the tracking servo operation may not be performed. Therefore, it is better to adjust the focus position before performing the tracking servo operation. Therefore, the amplitude of the reproduction signal is also adjusted before the tracking servo operates.

First, in the A5 processing section, the signal branches from the signal output from the tracking control section 20 depending on the polarity of the two values of 'H' and 'L'. When the tracking servo operation is not being performed, the tracking control unit 20 has output a signal of “L” and shifts to the D1 processing unit. As described above, the low-pass filter 9 smoothes the fluctuation component generated in the detection circuit 63 and outputs the fluctuation component to the averaging processing unit 10.
When the light beam is traversing the track, when the light beam is positioned between the tracks, there is no modulation due to the presence or absence of the pit, so the output of the envelope detection circuit 3 is the circuit offset level generated by the clamp circuit 62. become. This means that the output of the envelope detection circuit 3 fluctuates from the peak level to the level of the circuit offset when the light beam traverses one track. The averaging unit 10 averages this variation and outputs it. The averaging unit 10 needs to perform the averaging process for the maximum time required for the light beam to traverse one track. The maximum time required for a light beam to traverse one track depends on the rotation speed and the amount of eccentricity of the disk.
Fits within the time required for rotation. Therefore, the averaging process is operated for the time required for one rotation of the disk. If the averaging process is not completed in synchronization with the cycle in which the output of the envelope detection circuit 3 varies from the peak level to the offset level due to the light beam traversing the track, the output of the envelope detection circuit 3 will change from the peak level to the offset level. An error corresponding to the maximum half cycle of the cycle changing up to the above occurs in the output result of the averaging unit 10. In order to reduce the influence of this error, time averaging is performed not for one rotation of the disk but for several rotations, for example, three rotations. This will be specifically described. Disk rotation speed is 4320 rpm
, One cycle of the output pulse of the FG circuit 17 is 5.7.
Since it is 8 μs, the period counter 18 outputs 17 to the attenuator set value control unit 13. In the D2 processing unit, the attenuator set value control unit 13 determines that the rotation speed of the disk is 4 because the output value of the cycle counter 18 is 17.
It is determined that the rotation speed is 320 rpm, and the time required for one rotation is 13.8 ms. Therefore, the time required for three rotations is 41.4.
The number of times of averaging is set to 41400 μs２140 μs = 295 times so that the averaging processing unit 10 operates for ms.

Next, a procedure for determining the set value of the attenuator 7 in the attenuator set value control unit 13 will be described. First, in the D2 processing unit, a memory ME for storing a value limiting an upper limit of a settable range of the attenuator 7 is stored.
In the M-ATLMTU, the set value at which the amplification factor, which is the maximum setting limit of the attenuator 7, is quadrupled. Is set to 1/4 times. Next, the adjustment target value used by the attenuator set value control unit 13 in the D3 processing unit is stored in the memory MEM-RF.
Set to REF. The adjustment target value in the attenuator set value control unit will be specifically described. The description will be made on the assumption that the amplitude of the target reproduction signal is 100 mV. Where 10
Since the input of 0 mV is multiplied by 12.5 in the amplifier 61, the output of the envelope detection circuit 3 is 100 × 12.5 =
Since it is 1250, the output of the A / D converter 8 is 125. Therefore, the target value of the output value of the averaging unit 10 is 125. By the way, as the rotation speed of the disk increases, the speed at which the light beam passes through the pit row increases, and as a result, the modulation frequency of the signal input to the envelope detection circuit 3 also increases, but the operating band of the envelope detection circuit 3 is If the input signal is finite and the frequency is close to the operating limit, the peak level may not be detected correctly in the detection circuit 63.
The output of No. 3 becomes low. Assuming that the output of the detection circuit 63 is reduced by 10%, the output value of the averaging unit 10 is also reduced by 10%. Therefore, the rotation speed of the disk is determined from the output value of the cycle counter 18, and if the rotation speed of the disk exceeds the operating band of the envelope detection circuit 3, the adjustment target value is set small according to the decrease in the output of the detection circuit 63.
This will be specifically described. In the case of a disk having the same modulation degree as that of a CD, the highest detection frequency of the peak in the detection circuit 63 is considered when the light beam passes through the pit length 4T and the space length 3T.
939 MHz. At this time, it is assumed that the operating frequency of the detection circuit 63 is exceeded and the output is reduced by 10%. Here, similarly, it is assumed that the frequency is 6.170 MHz at 5400 rpm, which is 15% lower, and that the speed is 5940 rpm, which is 20% lower. The attenuator set value control unit 13 has information for converting the rate at which the output of the detection circuit 63 decreases in accordance with the rotation speed of the disk.
As described above, the attenuator set value control unit 13 determines that the rotation speed of the disk is 4320 rpm because the output of the cycle counter 18 is 17, and the detection circuit 6
From the information for converting the output reduction rate of No. 3, it is determined that the output of the detection circuit 63 is reduced by 10%. And adjustment target value 1
The value 112 obtained by lowering 25 by 10% is set as the adjustment target value. When the tracking control is not operating, as described above, the output of the envelope detection circuit 3 becomes the clamp level when the light beam passes through the area where the pit does not exist between the tracks. The value averaged and output by the averaging unit 10 is output to the detection circuit 63.
For the peak level at. Since the peak level of the clamp circuit 62 changes according to the setting of the attenuator 7, the amount of decrease in the output of the averaging unit 10 also changes according to the setting of the attenuator 7. However, when the outputs of the attenuators 7 are averaged, the amount of reduction is uniformly １ ／ of the value obtained by subtracting the clamp level from the peak level. More specifically, when the output of the attenuator 7 is 100 mV, considering that the offset of the clamp circuit 62 is removed by the above-described processing, the peak level is 100 mV and the clamp level is 0 mV.
It becomes 0 mV. Therefore, the adjustment target value may be reduced to ２. One-half of 125 is further subtracted from the target value 112 to obtain 62. This value is stored in the memory ME in the D3 processing unit.
Set to M-RFREF. Subsequently, the process proceeds to the A9 processing unit.

The operation after the A9 processing unit will be performed using specific numerical values in the description when the tracking servo operation is performed, which will be described later. Here, the outline of the operation shown in the flowchart shown in FIG. 2 will be briefly described.

The A9 processing unit sets the value stored in MEM-ATLMTL indicating the lower limit of the setting range of the attenuator 7 in the attenuator 7. In the subsequent A10 processing unit, the clamp circuit 62 stored in the MEM-OFS
Is subtracted from the output value of the averaging unit 10 by the value X = 37 corresponding to the circuit offset in
And In the subsequent A11 processing unit, the value Y 'is compared with the value stored in MEM-RFREF indicating the adjustment target value. If the input data does not exceed the value stored in the MEM-RFREF, the A12 processing unit determines that the amplitude of the target reproduction signal is not obtained with the currently set value of the attenuator 7, and the MEM-RFREF Is stored in the memory MEM-W1, and the difference value between the adjustment target value stored in
The A13 processing unit sets the attenuator 7 one step higher than the current set value of the attenuator 7 to increase the amplification factor.
In the subsequent A14 processing unit, the current setting value of the attenuator 7 indicates the upper limit value of the setting of the attenuator 7.
If it is determined that the value is smaller than the value stored in U, the set value of the attenuator 7 can be further increased.
The process returns to the 10 processing unit, and the processing after the A10 processing unit is repeated again. In the A14 processing unit, when the set value of the attenuator 7 becomes equal to the value stored in the MEM-ATLMTU indicating the upper limit, the process is terminated because the attenuator 7 cannot be set any more. When the value Y ′ representing the current amplitude of the reproduction signal exceeds the adjustment target value stored in the MEM-RFREF in the A11 processing unit, the value Y ′ representing the current amplitude and the MEM-RFREF are stored in the A15 processing unit. The difference value between the stored adjustment target value and the adjustment target value stored in the MEM-RFREF is stored in the memory MEM-W2 in the A16 processing unit. The value MEM-W1 is compared with the difference value MEM-W2 in the current setting of the attenuator 7. The value stored in MEM-W1 is MEM-W2
If the value is larger than the value stored in the MEM-RFREF, it is considered that the attenuator setting value is closest to the adjustment target value stored in the MEM-RFREF. Change the current setting
Memory MEM- for storing the final set value of the attenuator 7
It stores in ATEND and ends the processing. When the value stored in the MEM-W2 is larger, the previously set value of the attenuator 7 is close to the adjustment target value stored in the MEM-RFREF. Since it is considered to be near the amplitude of the reproduced signal, the setting value of the attenuator 7 is reset by the A17 processing unit so as to reduce the amplification factor by one step from the current setting value, and then the setting value is stored in the MEM-ATEND. And terminate the processing. With the above operation, the amplitude of the target reproduced signal can be adjusted.

Here, the output of the pickup unit 2 is set to 52 m
Specifically, when the attenuator 7 is set to have a double amplification rate, the output of the detection circuit 63 decreases by 10% and the value averaged by the averaging processing unit 10 is set to V. Amplifier 61 taking into account that it becomes 1/2
Has an amplification rate of 12.5 times, so that 52 × 2 × 0.9 ×
1/2 × 12.5 = 585 mV, and therefore the value Y ′
Is 58. In the case where the setting of the attenuator 7 is set to have an amplification factor of 9/4 times higher than that of the other stage, similarly, 52 × 9/4 × 0.9 × 1/2 × 12.5 = 658 mV
Therefore, the value Y ′ is 65. Adjustment target value ME
Since M-RFREF is 62 as described above, the difference value between the adjustment target value and the value Y ′ is smaller when the attenuator 7 is set to have an amplification factor of 9/4, and as a result, the setting of the attenuator 7 The value is set to have an amplification factor of 9/4.

Next, the function when the tracking servo is operating will be described. Adjustment of the amplitude of the reproduced signal performed when the tracking servo is not operating has a problem that an adjustment error is likely to occur. The reason is that, as described above, when the light beam traverses the track, the output of the envelope detection circuit 3 varies from the peak level of the clamp circuit 62 to the offset level. , And the adjustment accuracy is degraded. In addition, since the output of the averaging unit 10 is not completely halved, an adjustment error occurs. Therefore,
It is desirable to adjust the amplitude of the reproduction signal again while the tracking servo is operating. However, in order to shorten the start-up time of the apparatus, the execution time of the process is shortened on the assumption that the amplitude of the reproduced signal is adjusted once. The operation will be specifically described below. Here, the amplitude of the reproduced signal adjusted when the tracking servo is not operating is 52 × 9/4 = 117 mV, and the attenuator 7 at this time is set to have an amplification factor of 9/4. Suppose.

First, the operating state of each component in FIG. 1 when the tracking servo is operating will be described.

The rotation speed of the disk 1 changes from 4320 rpm when the tracking servo is not operating.
It is assumed that the spindle motor 4 is rotating at 2000 rpm. The semiconductor laser emits light at a predetermined power by the laser control unit 12, and is controlled by the focus control unit so as to be in a predetermined focusing state on the disk 1. At this time, the laser control unit 12 outputs an “H” signal. Further, the tracking servo operation is performed by the tracking control unit 20, the light beam follows a track located in the recording unit of the disk, and the tracking control unit 20 outputs an “H” signal. Further, the defect detection circuit 14, the off-track detection circuit 15, and the address section detection circuit 16 output “L”, the AND circuit B becomes “L”, and the switch 11 becomes O.
It is assumed that the state is N. Defect detection circuit 14, off-track detection circuit 15, and address part detection circuit 16
Output 'H' will be described later. Since the time required for one rotation of the disk is 30 ms, the FG circuit 17
Is one cycle of 1.25 ms, and the value of 3753 is obtained from the cycle counter 18 by the attenuator set value control unit 1.
3 has been entered. A memory MEM for storing a circuit offset generated by the envelope detection circuit 3
X = 37 is stored in -OFS, and the memory MEM-ATEND for storing the set value of the attenuator 7 is a 9 / 4-fold amplification finally set in the processing when the tracking servo is not operating. It is assumed that a set value corresponding to the rate is stored.

First, since the output of the laser control unit 12 is H, the process branches from the A0 processing unit to the A1 processing unit. The A1 processing unit performs the initial setting of the attenuator 7. As a setting value to be initially set, a setting value that is 9/4 times the value set in MEM-ATEND is set. Also, the memory MEM-CNT is set to 0. In the subsequent A2 processing unit, as described above, the averaging processing unit 10 sets the average number of times to 10 in consideration of disturbance such as noise. The A3 processing unit performs a process of subtracting the value X = 37 stored in the MEM-OFS from the output value of the averaging processing unit 10 and sets the result to Y. Then, the threshold value x = 2 for detecting that the light beam is in the unrecorded portion is compared with the value Y in the A4 processing unit. At this time, 117 mV is output from the attenuator 7, and the value Y becomes 146. Therefore, the processing shifts to the A5 processing unit. Tracking control unit 2
Since 0 outputs a signal of "H", the process proceeds to the A6 processing unit. In the A6 processing unit, the averaging processing unit 10 sets the average number of times. When the tracking servo is operating, there is no output fluctuation of the envelope detection circuit 3 caused by the light beam crossing the track as described above. However, the film formation of the disk is not uniform, and the output signal of the envelope detection circuit 3 may fluctuate when the light beam scans the track for a time corresponding to one rotation of the disk. Accordingly, the attenuator set value control unit 13 sends the average number of times 300 to the averaging processing unit 10 so that the output of the A / D converter 8 is averaged during the time 30 ms during which the disk rotates once.
00 ÷ 140 = 214 times is set. Here, when the tracking servo is operating, the amplitude of the reproduction signal has been adjusted before, and it can be said that the amplitude of the reproduction signal is near the target amplitude value. It is assumed that the attenuator 7 can be adjusted only by changing the currently set value by two or three steps. Specifically, when the setting value is set to a setting value corresponding to the amplification factor of 9/4, any one of the setting values corresponding to the amplification factor of 7/4 to 11/4 is set. . In order to shorten the processing time in the A7 processing unit, a value corresponding to an amplification factor of 11/4 times is set in a memory MEM-ATLMTU storing a value limiting an upper limit of a settable range of the attenuator 7, and a value limiting a lower limit. Is set to the memory MEM-ATLMTL storing the value corresponding to the amplification factor of 7/4. This processing eliminates the time required by setting unnecessary attenuators 7 in the processing subsequent to the A8 processing unit. The A8 processing unit sets the adjustment target value to MEM-RFREF as in the D3 processing unit. Here, as described above, the amplitude of the target reproduction signal is adjusted so that the output of the attenuator 7 becomes 100 mV. When the output of the attenuator 7 is 100 mV, A /
The output of the D converter 8 is 125. Here, when the disk rotation speed is 2000 rpm, it is assumed that the maximum frequency of the peak detection frequency in the detection circuit 63 is 2.284 MHz and does not exceed the operating frequency limit of the detection circuit 63. The attenuator set value control unit 13 sets the rotation speed of the disk to 2000 rpm based on the value 3753 of the cycle counter 18.
m is determined, and it is determined that it is not necessary to lower the adjustment target value based on information held internally and used for converting the output reduction ratio in the detection circuit 63. Therefore, MEM-RFREF has 12
Set 5. Subsequently, in the A9 processing unit, the attenuator 7
Is set in the attenuator 7 to a value corresponding to a 7 / 4-fold amplification factor stored in the MEM-ATLMTL indicating the lower limit of the setting range. Here, the output of the pickup unit 2 is 52
At mV, the circuit offset generated in the envelope detection circuit 3 is 370 mV. The output of the pickup unit 2 is multiplied by 7/4 by the attenuator 7 to be 91 mV.
Therefore, the output of the envelope detection circuit 3 is multiplied by 12.5 by the amplifier 61, and further added with a circuit offset to 15
07 mV.

At this time, the output of the averaging unit 10 is 15
It becomes 0. In the subsequent A10 processing unit, the value X stored in the MEM-OFS is calculated from the output value 150 of the averaging processing unit 10.
= 37 is subtracted, and the result is set to Y '= 113. In the A11 processing unit, the value of Y ′ and M indicating the adjustment target value are set.
The magnitudes of the values stored in EM-RFREF are compared. Since Y ′ = 113 is equal to or less than 125 stored in the MEM-RFREF, the processing shifts to the A12 processing unit. In the A12 processing unit, the difference value 12 between the value stored in the MEM-RFREF and the value of Y ′ is stored in the memory MEM-W1,
In the A13 processing unit, the attenuator 7 is set to a set value corresponding to a gain two times higher than the current set value corresponding to 7/4 times the gain of the attenuator 7. Subsequently, the process proceeds to the A14 processing unit, where the set value of the attenuator 7 corresponding to the current double amplification factor is compared with the value stored in the MEM-ATLMTU. 11 for MEM-ATLMTU
Since the value corresponding to the amplification factor of / 4 is stored, it is determined that the current setting value of the attenuator 7 is smaller, and the process proceeds to the A10 processing unit. At this time, the output value of the averaging processing unit 10 is 167, and Y ′ = 167−37 = 1 in the A10 processing unit.
It will be 30. In the subsequent A11 processing unit, the value of Y ′ is ME
Since it is larger than the value stored in M-RFREF, A1
The 5 processing unit stores 5 which is a difference value between the value stored in the MEM-RFREF and the value of Y ′ in the memory MEM-W2. Subsequently, the MEM-W1 and ME
Compare the values stored in MW2. MEM-W1
Contains 12 and MEM-W2 contains 5, so it is determined that the current attenuator setting value is close to the value stored in MEM-RFREF which is the adjustment target value, and The set value corresponding to the double amplification rate is stored in the memory MEM-ATEND, and the process ends. Therefore, the set value corresponding to the double amplification factor is selected for the attenuator 7, and the amplitude of the output signal is set to 10 near the target amplitude.
It becomes 4 mV.

Next, the operation when the light beam passes through the defect will be described. Defects are dirt or scratches adhering to the disk surface. When a light beam passes over the defect, the modulation amplitude due to the presence or absence of pits decreases, and as a result, the amplitude of the output signal of the pickup unit 2 decreases. Accordingly, the peak level in the detection circuit 63 decreases, so that the output of the envelope detection circuit 3 fluctuates. Due to this variation, if the averaging processing unit 10 is operated while passing through the defect, an error occurs in the output value of the averaging processing unit 10. When the tracking control unit 20 performs the tracking servo operation, the defect detection circuit 14 outputs a signal “H” when the light beam detects that the light beam passes over the defect, and as a result, the switch 11 It turns off. The averaging processing unit 10 continues the processing of adding the value input immediately before the switch 11 is turned off until the defect detection circuit 14 outputs a signal of “L” and the switch 11 is turned on. Accordingly, it is possible to prevent the fluctuation of the output signal of the envelope detection circuit 3 generated when the light beam passes through the defect from affecting the output value of the averaging processing unit 10. The operation will be briefly described with reference to FIG. FIG. 13- (a) shows the A / D converter 8
Are shown on the horizontal axis as time. (B)
Indicates the output value of the averaging unit 10 when the value shown in (a) is input with the horizontal axis representing time so as to indicate synchronization with the broken line, and (c) shows the defect value when the horizontal axis represents time. The output of the detection circuit 14 is shown. As shown in (c) and (a), while a defect is detected, the envelope detection circuit 3 fluctuates for the above-described reason.
The output of the D converter 8 fluctuates. However, since the switch 11 is turned off, the averaging unit 10 performs an averaging of the input values before the defect is detected.
As shown in (b), there is no influence of the defect on the output.
When the tracking servo operation is not performed, since the light beam crosses the track, the amplitude of the output signal of the pickup unit 2 is reduced, and the defect detection circuit 14 outputs “H”. Therefore, in order to prevent the input of the averaging processing unit 10 from being stopped irregularly, the switch 11 is always ON while the tracking control unit 20 outputs the signal of “L”.

Next, the operation when the light beam goes off-track will be described. Off-track means that the light beam deviates from the track being scanned and is at a position where there is no pit row. When the light beam is off-track, there is no modulation due to the presence or absence of pits in the pickup unit 2,
As a result, the amplitude of the output signal of the pickup unit 2 decreases. This causes the output of the envelope detection circuit 3 to fluctuate. When the tracking control unit 20 is performing the tracking servo operation, when the off-track detection circuit 15 detects that the light beam is off-track, the signal “H” is output.
Is output, and as a result, the switch 11 is turned off. The averaging unit 10 includes an off-track detection circuit 15
Until the switch 11 is turned on and the switch 11 is turned on, the process of adding the value input immediately before the switch 11 is turned off is continued. Thus, it is possible to prevent the fluctuation of the output signal of the envelope detection circuit 3 generated when the light beam goes off-track from affecting the output value of the averaging processing unit 10. The operation will be briefly described with reference to FIG. FIG. 14A shows the output value of the A / D converter 8 with time on the horizontal axis. (B) shows the output value of the averaging unit 10 when the value shown in (a) is input with the horizontal axis representing time so as to indicate synchronization with the broken line, and (c) shows the output value on the horizontal axis. The output of the off-track detection circuit 15 at the time is shown. As shown in (c) and (a), while the off-track is detected, the envelope detection circuit 3
Vary for the above reason, the output of the A / D converter 8 varies. However, since the switch 11 is turned off, the averaging unit 10 adds and averages the input values before the off-track is detected, so that the output does not have the effect of the off-track as shown in FIG. When the tracking servo operation is not performed, the output signal of the off-track detection circuit 15 becomes “H” or “H” every time the light beam crosses the track.
L 'changes. Therefore, in order to prevent the input of the averaging processing unit 10 from being stopped irregularly, the tracking control unit 2
The switch 11 is always turned on while the signal of “0” is output as “L”.

Next, the operation when the light beam passes through the address section will be described. In a disk having an address portion having a structure similar to that of a DVD-RAM disk, the address portion is formed by pits, and the data portion has a structure in which data is recorded by a change in irradiation power of laser. Therefore, the amplitude of the modulation signal output from the pickup unit 2 differs between the address unit and the data unit. The purpose is to adjust the amplitude in the data section to the target amplitude, and a change in the amplitude in the address section causes a change in the output of the envelope detection circuit 3. Therefore, when the tracking control unit 20 is performing the tracking servo operation, when the address unit detection circuit 16 detects that the light beam is passing through the address unit, the signal becomes “H”.
Is output, and as a result, the switch 11 is turned off. The averaging unit 10 is configured such that the address unit detection circuit 16
Until the switch 11 is turned on, the processing of adding the value input immediately before the switch 11 is turned off is continued. Accordingly, it is possible to prevent the fluctuation of the output signal of the envelope detection circuit 3 generated when the light beam passes through the address section from affecting the output value of the averaging processing section 10. The operation will be briefly described with reference to FIG. FIG.
FIG. 3A shows the output value of the A / D converter 8 with time on the horizontal axis. (B) shows the output value of the averaging unit 10 when the value shown in (a) is input with the horizontal axis representing time so as to indicate synchronization with the broken line, and (c) shows the output value on the horizontal axis. The output of the address part detection circuit 16 at the time is shown. While the address portion is detected as shown in (c) and (a), the output of the A / D converter 8 fluctuates because the envelope detection circuit 3 fluctuates for the above reason.
However, since the switch 11 is turned off, the averaging processing unit 10 adds and averages the input values before the detection of the address portion, so that the output has no influence of the address portion as shown in FIG. When the tracking servo operation is not performed, the timer inside the address section gate signal generation circuit 103 uses the timer within the address section gate signal generation circuit 103 until the light beam reaches the address section once after passing through the address section because the light beam crosses the track. The time cannot be obtained accurately, and as a result, the output signal of the address section detection circuit 16 may not be correct. Therefore, in order to prevent the input of the averaging processing unit 10 from being stopped irregularly, when the tracking control unit 20 outputs “L”, the switch 11 is independent of the operation state of the address unit detection circuit 16. Is O
The state becomes N.

As described above, the attenuator set value control unit 1
By operating the function 3, the amplitude of the reproduced signal can be adjusted to the target amplitude without affecting the operation state of the apparatus.

(Embodiment 2) FIG. 17 is a block diagram showing an optical disk device according to a second embodiment of the present invention.
In the description of FIG. 17, the same components as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 17, the output of the switch 11 is input to a low-pass filter 171 whose cutoff characteristic can be set variably. For the low-pass filter 171, a constant indicating a cutoff characteristic is set by the attenuator set value control unit 13. The low-pass filter 171 changes the cutoff characteristic in accordance with the set constant, so that the low-pass filter 9 in FIG.
Function and the function of the averaging processing unit 10 and output to the attenuator set value control unit 13. Specifically, the cutoff frequency of the low-pass filter 171 is set to 2
By setting the frequency to 0 kHz or less, the same function as the low-pass filter 9 in FIG.
The same function as the averaging processing unit 10 is achieved by setting a lower cutoff frequency in accordance with the output value and the operation state of the tracking control unit 20.

The specific operation of the low-pass filter 171 will be described with reference to FIG. Also in the description of FIG. 18, the same processes as those in FIG. 2 are denoted by the same reference numerals as those in FIG.

First, the operation when the laser is not emitting light will be described. Since the laser control unit 12 outputs “L” in the A0 processing unit, a constant for determining the cutoff frequency is set in the low-pass filter 171 in the BS1 processing unit. When the laser is not emitting, the A / D converter 8 outputs the circuit offset generated by the envelope detection circuit 3 as described above. This circuit offset is output as a DC value for each device. Therefore, since the low-pass filter 171 does not need to operate its function, the attenuator set value control unit 13 sets a constant such that the cut-off frequency of the low-pass filter 171 can be set to an upper limit, for example, 50 kHz. . In the subsequent BS2 processing unit, the output of the low-pass filter 171 is stored in a memory MEM-
The information is stored in the OFS, and the processing is terminated.

Next, the operation when the light beam is in the unrecorded portion will be described. Low pass filter 1 in AS1 processing unit
A constant for determining the cutoff frequency is set to 71. As described above, when the light beam is in the unrecorded portion of the disk, the output of the envelope detection circuit 3 is
Since there is no fluctuation of the output due to the clamp level at
The cutoff frequency of the low-pass filter 171 is the maximum of 50 k, as in the case where the laser is not emitting light.
Set Hz. The subsequent AS3 processing unit performs a process of subtracting the value X stored in the MEM-OFS from the output value of the low-pass filter 171 and sets the result to Y. Subsequent processing is the same as in FIG.

Next, the operation when the tracking servo is not operating will be described. First, as described with reference to FIG. 8, the output of the envelope detection circuit 3 decreases at a constant time constant in the detection circuit 63, and thus the output of the envelope detection circuit 3 fluctuates. Low-pass filter 17
1 needs to have a cut-off frequency of 20 kHz or less, similar to the low-pass filter 9 in FIG. When the tracking servo is not operating, the output of the envelope detection circuit 3 is clamped when the light beam crosses the track and when the light beam is located at a place where no pit exists between the tracks. Circuit 62
Of the clamp level. The low-pass filter 171 performs a process of smoothing output fluctuations from the peak level to the clamp level in the clamp circuit 62. This variation varies according to the setting of the attenuator 7. However, it is only necessary to suppress the amount of fluctuation that occurs when the reproduced signal is near the target amplitude, and the operation of setting the attenuator 7 from the lower limit of the setting range is performed as described with reference to FIG. Therefore, it is not necessary to consider a variation larger than the variation when the amplitude becomes close to the target amplitude. Therefore, since the target amplitude of the output signal of the attenuator 7 is 100 mV, it is sufficient to consider a fluctuation amount occurring when the light beam crosses the track to about 100 mV. The frequency of the fluctuation output from the envelope detection circuit 3 when the light beam crosses the track changes according to the eccentricity and the rotation speed of the disk. However, the lowest frequency is uniquely determined according to the rotation speed of the disk. The lowest frequency when a light beam traverses one track is 4320r for a disk.
When rotating at pm, the rotation frequency is 72 Hz. Here, since the A / D converter 8 outputs a value of 1 for an input of 10 mV, the attenuator set value control unit 13
In order to suppress the maximum input error to 1 or less, it is considered that the above fluctuation is suppressed to 1/10 of 10 mV in the low-pass filter 171. At this time, the cutoff frequency may be set to 7.2 Hz. As described above, since the cutoff frequency is 20 kHz or less, the fluctuation component shown in FIG. 8 is also smoothed. Therefore, DS1
In the processing unit, the attenuator set value control unit 13 determines that the rotation speed of the disk is 4320 rpm from the value 17 output from the cycle counter 18, and sets a cut-off frequency of 7.2 Hz for the low-pass filter 171. Set.

The subsequent processing performs the same operation as described with reference to FIG.

Finally, the operation when the tracking servo is operating will be described. While the tracking servo is operating, there is no fluctuation component caused by the light beam crossing the track. Therefore, the low-pass filter 171
Is used to smooth the output fluctuation of the detection circuit 63 described with reference to FIG. Therefore, in the AS6 processing unit, the attenuator set value control unit 13 controls the low-pass filter 1
A constant is set to 71 so that the cutoff frequency is 20 kHz. Subsequent processing performs the same operation as described in FIG. 2 except for the AS109 processing unit.

The AS10 processing unit is a process of setting the value obtained by subtracting the value X stored in the memory MEM-OFS from the output value of the low-pass filter 171 in place of the averaging processing unit 10 in the A10 process as Y '. .

In the above embodiment, each control unit is shown as an independent circuit configuration. However, the components following the A / D converter 8 and below in FIG. 1 include a low-pass filter 9, an averaging unit 10, Switch 11, attenuator set value controller 13, OR circuit A, AND circuit B, and low-pass filter 17 in FIG.
1 can be constituted only by software using a processor such as a microcomputer having an arithmetic unit and a memory, and the other components other than the attenuator 7 are standard components in an existing optical disk device, so that cost is reduced. Can be realized with almost no rise.

[0096]

As described above, according to the present invention, not only the reproduction signal can be adjusted to the target amplitude for each optical disk having a different reflectance, but also the amplitude of the reproduction signal can be adjusted according to the operation state of the apparatus. This has an advantageous effect that the accuracy of the focus position adjustment when the tracking servo is not operating can be improved. Furthermore, since the adjustment can be performed regardless of the operation state of the apparatus, there is an advantageous effect that the amplitude of the reproduction signal can be adjusted again without changing the operation state of the apparatus when a reading error of the reproduction signal occurs. can get. Further, according to the present invention, in an optical disc having many unrecorded areas where no data is recorded,
An advantageous effect that the amplitude of the reproduction signal can be surely adjusted in the recording section is obtained. Further, according to the present invention, an advantageous effect is obtained that the amplitude of the reproduction signal of the data portion can be adjusted to the target amplitude without being affected by the address portion, with respect to the optical disc having the address portion.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of an attenuator set value control unit in FIG. 1;

FIG. 3 is a configuration diagram of an attenuator in FIG. 1;

FIG. 4 is a diagram for explaining the operation of the attenuator in FIG. 1;

FIG. 5 is a diagram showing set values of an attenuator in FIG. 1;

FIG. 6 is a configuration diagram of an envelope detection circuit in FIG. 1;

FIG. 7 is a diagram for explaining the operation of the off-track detection circuit in FIG. 1;

FIG. 8 is a diagram for explaining the operation of the envelope detection circuit in FIG. 6;

9 is a diagram for explaining a frequency at which a peak level is detected in the detection circuit in FIG. 6;

FIG. 10 is a configuration diagram of an address part detection circuit in FIG. 1;

11 is a diagram for explaining the operation of the address section detection circuit in FIG. 1;

FIG. 12 is a diagram for explaining the operation of the clamp circuit in FIG. 1 when a light beam crosses a groove on an unrecorded track;

FIG. 13 is a view for explaining the operation of the averaging unit when the defect detection circuit in FIG. 1 is operating;

14 is a view for explaining the operation of the averaging processing unit when the off-track detection circuit in FIG. 1 is operating;

FIG. 15 is a view for explaining the operation of the averaging processing unit when the address unit detection circuit in FIG. 1 is operating;

FIG. 16 is a diagram for explaining the operation of the switch 11 in FIG. 1;

FIG. 17 is a block diagram showing a second embodiment of the present invention.

18 is a flowchart showing the operation of the attenuator set value control unit in FIG.

FIG. 19 is a block diagram showing an example of an optical disk having a conventional reproduction signal amplitude adjustment function.

[Explanation of symbols]

 Reference Signs List 1 optical disk 2 pickup unit 3 envelope detection circuit 4 spindle motor 5 traverse 6 traverse motor 7 attenuator 8 A / D converter 9 low-pass filter 10 averaging processing unit 11 switch 12 laser control unit 13 attenuator set value control unit 14 defect detection Circuit 15 Off-track detection circuit 16 Address detection circuit 17 FG circuit 18 Period counter 19 Traverse control unit 20 Tracking control unit SW1 Switch 1 SW2 Switch 2 SW3 Switch 3 SW4 Switch 4 R1 Resistance 1 R2 Resistance 2 R3 Resistance 3 R4 Resistance 4 31 Attenuator value setting value 32 Attenuator section 33 Amplifier 61 Amplifier 62 Clamp circuit 63 Detection circuit 101 Data slice circuit 102 Address reading circuit 103 Address section Gate signal generation circuit 171 Low-pass filter 191 Amplifier 192 Control circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Mutsumi Iguchi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 5D044 BC06 CC04 DE46 FG04 5D090 AA01 BB04 CC04 EE13 FF02

Claims (25)

[Claims] 1. A reproducing means for reproducing information recorded on a disk, an amplifier for variably setting a gain for amplifying an output of the reproducing means, and an amplitude detector for detecting an amplitude from an output of the amplifier. A smoothing processor for smoothing the output of the amplitude detector, and a gain setting for setting the gain of the amplifier in accordance with the output of the smoothing processor to set the output of the amplifier to a predetermined amplitude. An optical disc device, comprising: a unit for changing a smoothing process of the smoothing processing unit according to an operation state of the device. 2. The gain setting unit according to claim 1, wherein the gain of the amplifying unit is set to a predetermined amplitude by setting the gain of the amplifying unit so that the output of the smoothing processing unit has a predetermined target value. Item 2. The optical disk device according to item 1. 3. The optical disk device according to claim 2, wherein the target value is changed according to an operation state of the device. 4. The method according to claim 3, wherein the target value is changed when the tracking control for causing the reproducing means to follow the track on the disk is operating and when it is not operating.
An optical disk device as described in the above. 5. The optical disk apparatus according to claim 4, wherein the target value is set lower when the tracking control is not operating than when the tracking control is operating. 6. The smoothing process of the smoothing processing unit according to claim 1, wherein a tracking control for causing the reproducing means to follow a track on the disk is operated and not. Optical disk device. 7. The gain setting section is operated when the tracking control is not operating to set the gain of the amplifier section. Then, when the tracking control is operating, the gain setting section is operated to set the gain of the amplifier section again. 7. The optical disk device according to claim 4, wherein: 8. A setting storage means for storing a set value of the amplifying section, wherein the set value of the amplifying section when the tracking control is not operated is stored in the storage means, and the tracking control is operated. 8. The optical disk apparatus according to claim 7, wherein when the setting is made, the range in which the gain of the amplifying unit can be set is limited to a range obtained by increasing or decreasing a set value stored in the setting storage means by a fixed amount. 9. The optical disk device according to claim 8, wherein the output of the amplitude detector is set to a target value by changing the gain in the amplifying section from the lowest setting in the settable range to the largest setting. 10. A defect detection unit for detecting the attachment or defect of a scratch or dust on a disk, and stopping the output of the amplitude detection unit when the defect detection unit detects the attachment or defect of a disc on the disk. 2. The optical disk device according to claim 1, wherein: 11. An off-track detecting section for detecting that the reproducing means has deviated from the track being scanned, and an amplitude when the off-track detecting section has detected that the reproducing means has deviated from the track being searched. 2. The optical disk device according to claim 1, wherein the output of the detection unit is stopped. 12. The optical disk device according to claim 10, wherein the operation of the defect detection unit is stopped when the tracking control is not operating. 13. The optical disk device according to claim 11, wherein the operation of the off-track detection unit is stopped when the tracking control is not operating. 14. The optical disk according to claim 1, further comprising a period detector for detecting a rotation period of the disk, wherein a smoothing process in a smoothing processing unit is changed in accordance with an output of the period detector. apparatus. 15. The optical disk device according to claim 14, wherein the smoothing process is performed over a period equal to or longer than the disk rotation time detected by the period detector. 16. The optical disk device according to claim 3, further comprising a period detector for detecting a rotation period of the disk, wherein the target value is changed according to an output of the period detector. 17. The optical disk device according to claim 16, wherein the target value is reduced as the output of the period detector decreases. 18. The optical disk device according to claim 1, wherein the smoothing processing unit is constituted by a low-pass filter capable of changing a cutoff characteristic. 19. The optical disk apparatus according to claim 6, wherein the smoothing processing of the smoothing processing section is an averaging processing in which the number of additions can be set from outside. 20. The method according to claim 19, wherein when the tracking control is not operating, the number of additions of the averaging process is increased compared to when the tracking control is operating.
An optical disk device as described in the above. 21. A reproducing means comprising a light source for irradiating a light beam to a disk and a detector for receiving reflected light or transmitted light from the disk, and stores an output value of an amplitude detector when the light source is not emitting light. 2. The optical disk apparatus according to claim 1, further comprising an offset storage unit, wherein the value stored in the offset storage unit is subtracted from an output value of the amplitude detector when the light source emits light. 22. A reproducing means for reproducing information recorded on a disc, a moving means for moving the reproducing means in a radial direction of the disc, and an unrecorded portion detection for detecting that the reproducing means is located at an unrecorded portion. Means, an amplifying unit capable of variably setting a gain for amplifying an output of the reproducing means, an amplitude detecting unit for detecting an amplitude from an output of the amplifying unit, and a gain of the amplifying unit according to an output of the amplitude detecting unit. And a gain setting unit for setting the output of the amplifying unit to a predetermined amplitude, and the moving unit to a position where the unrecorded unit detecting unit does not detect when the reproducing unit is located in the unrecorded unit. An optical disk device characterized in that a reproducing means is moved by the method. 23. The optical disk apparatus according to claim 22, wherein the unrecorded portion detecting means detects that the reproducing means is located in the unrecorded portion when the output of the amplitude detecting portion is equal to or less than a predetermined value. 24. A reproducing means for reproducing information recorded on a disc, an amplifying section capable of variably setting a gain for amplifying an output of the reproducing means, and an amplitude detecting section for detecting an amplitude from an output of the amplifying section. A gain setting unit that sets a gain of the amplifying unit according to an output of the amplitude detecting unit to set an output of the amplifying unit to a predetermined amplitude, and an address for identifying an area on a disk. An address section detecting section for detecting that the reproducing section is located at the address section, and an output of the amplitude detecting section when the address section detecting section detects that the reproducing section is located at the address section. An optical disk device characterized by stopping the operation. 25. The optical disk apparatus according to claim 24, wherein the operation of the address section detecting means is stopped when the tracking control is not operating.