JP4148822B2 - Optical disc apparatus and control program therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk apparatus that records and / or reproduces information by irradiating an information recording surface of a mounted optical disk with a light spot from a pickup and detecting the reflected light.
[0002]
[Prior art]
The optical disk devices that are widely used today include those that only reproduce information recorded on read-only optical disks (CD, CD-ROM, DVD, DVD-ROM, etc.) and write-once optical disks (CD-R, CD). -RW, DVD-R, DVD-RW, etc.) for recording / reproducing information. These optical disc apparatuses are configured to record and / or reproduce information by irradiating an information recording surface of a mounted optical disc with a light spot from a pickup and detecting the reflected light.
[0003]
In such an optical disc apparatus, it is necessary to accurately irradiate a track on which information on the optical disc is recorded with a light spot, and therefore it is necessary to adjust the relative position between the optical disc and the pickup with high accuracy. For this reason, the optical disc apparatus described above is detected by the pickup with tracking drive means for adjusting the tracking for the loaded optical disc, focus drive means for adjusting the depth of focus of the light spot, sled drive means for adjusting the thread position of the pickup, and pickup. And a control means for controlling each drive means based on the error signal.
[0004]
In the optical disk apparatus having the above-described configuration, when performing a track jump operation in which a plurality of tracks are jumped to a target track at a time, the pickup is first performed by the tracking drive means while detecting the tracking error signal output from the pickup. Driving control (so-called traverse movement) in which the posture of the objective lens is adjusted and the center of the light spot is moved to the target track, and then the pickup is moved directly below the target track by the sled driving means accordingly. ) Was done. In the drive control described above, by using an auto sequencer in the control DSP [Digital Signal Processor], both the drive means cooperate in accordance with the tracking error signal output from the pickup, and the traverse moving speed is constant. .
[0005]
[Patent Document 1]
JP 2002-208154 A
[Patent Document 2]
Japanese Patent Laid-Open No. 11-213395
[0006]
[Problems to be solved by the invention]
Certainly, like the optical disk apparatus having the above-described configuration, the tracking drive signal and the thread drive signal are generated based on the tracking error signal output from the pickup, and the thread drive means when the thread drive signal exceeds a predetermined threshold value If the tracking driving means and the sled driving means cooperate with each other, the traverse moving speed can be kept constant and the track jump operation can be performed with high accuracy.
[0007]
However, an eccentric component of the optical disc is superimposed on the tracking drive signal. Therefore, in the optical disk apparatus having the above configuration, when a tracking error signal is generated due to the eccentricity of the optical disk, the tracking error signal is within a range that can be processed only by the tracking drive means (only the attitude adjustment of the objective lens). Even so, the operation control of the thread driving means is performed in response to this, and there is a problem that the thread driving means unnecessarily sensitively reacts. When the sled driving means reacts sensitively in this manner, the tracking driving and sled driving of the pickup are in opposite phases, which may cause a hunting phenomenon. In particular, as the density of information recorded / reproduced with respect to an optical disc increases, the hypersensitive reaction of the thread driving means caused by disturbance such as eccentricity has become a factor of deteriorating information recording / reproduction accuracy.
[0008]
As a means for solving the above-described problem, a method is conceivable in which the thread driving means is not operated for a tracking error signal that is equal to or less than a predetermined threshold by passing the tracking error signal through a low-pass filter. However, in such a configuration, if the detection sensitivity of the error signal is increased, it becomes impossible to prevent the hypersensitive reaction of the thread driving means, and if the detection sensitivity is decreased, the cut-off frequency of the low-pass filter must be set considerably low, and the thread position Because of the dilemma that adjustments are less responsive, it was not the best configuration.
[0009]
Conventionally, the offset representative value is calculated from the tracking drive offset value for one rotation of the optical disc, and the comparison result between the offset representative value and the offset center value (tracking drive offset value when tracking adjustment is not performed) is used. Based on this, an optical disc apparatus that performs sled drive determination has been disclosed and proposed (see, for example, Patent Document 1). Conventionally, a track pitch measurement method for calculating a track pitch by moving a pickup by a predetermined step and counting the number of tracks crossing between the steps has been disclosed and proposed (for example, see Patent Document 2).
[0010]
In view of the above-mentioned problems, the present invention improves the information recording / reproducing accuracy by preventing the hypersensitive reaction of the sled driving means due to the eccentricity of the optical disk and ensuring sufficient responsiveness of the sled position adjustment. It is an object of the present invention to provide an optical disc apparatus and a control program for the same.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, an optical disc apparatus according to the present invention includes a pickup that irradiates a beam onto an optical disc and detects reflected light thereof, a spindle motor that rotates the optical disc, and the pickup in the radial direction of the optical disc. A rotation monitoring means for monitoring the number of rotations of the disk in an optical disk device that records and / or reproduces information on the optical disk, One step From the feed amount and the track pitch of the optical disc, One step The disk rotation speed corresponding to the feed amount is obtained as a threshold value, and the threshold value is compared with the disk rotation speed obtained by the rotation monitoring means. Above Thread drive determination means for determining whether the thread motor can be driven; Based on the determination result of the thread drive determination means, a control means for causing the thread motor to send only one step when the disk rotation speed reaches the threshold value; It is set as the structure which has. By adopting such a configuration, it is possible to prevent the hypersensitive reaction of the sled driving means due to the eccentricity of the optical disk and to sufficiently ensure the responsiveness of the sled position adjustment, thereby improving the information recording / reproducing accuracy. Is possible.
[0012]
The optical disk apparatus having the above-described structure is obtained when a predetermined amount of tracking drive signal detection means for detecting a tracking drive signal for detecting a tracking focus signal for causing the beam focusing point of the pickup to follow the track of the optical disk is driven by a predetermined amount. Track pitch calculation means for calculating the track pitch of the optical disk from the amount of change in the tracking drive signal obtained and the amount of change in the tracking drive signal obtained when the optical disk is rotated with the sled motor stopped. It is good to have a configuration comprising As described above, by calculating the track pitch of the optical disc one by one and performing the sled drive determination using the calculated value, it is possible to further improve the thread feeding accuracy.
[0013]
The optical disk apparatus having the above-described configuration may be configured to include a low-pass filter that selectively passes only the low frequency component of the tracking drive signal to the tracking drive signal detection means. As described above, the configuration in which the thread feeding control is performed using the signal obtained by removing the eccentric component (AC component) from the tracking drive signal instead of the tracking error signal is hardly affected by the eccentric component of the optical disk. Thus, it is possible to realize highly accurate feed control.
[0014]
Further, in the optical disc apparatus having the above-described configuration, the tracking drive signal detecting means detects the tracking drive signal in a timely manner during the reproduction of the optical disc, calculates the amount of change thereof, and compares the calculated value with the previous calculated value. The tracking gain correction may be performed based on this. With such a configuration, the tracking gain is always corrected even during reproduction of the optical disc, so that it is possible to further improve the accuracy of tracking drive control and sled drive control.
[0015]
Further, a control program according to the present invention includes a pickup that irradiates a beam to an optical disc and detects reflected light thereof, a spindle motor that rotates the optical disc, a sled motor that moves the pickup in the radial direction of the optical disc, and a system A control program for controlling an optical disk device that records and / or reproduces information on the optical disk in a control program for monitoring the rotational speed of the disk. Monitoring means , Of the thread motor One step From the feed amount and the track pitch of the optical disc, One step The disk rotation speed corresponding to the feed amount is obtained as a threshold value, and the threshold value is compared with the disk rotation speed obtained by the rotation monitoring means. Above Thread drive determination means for determining whether or not the thread motor can be driven; And, based on the determination result of the sled drive determining means, a control means for sending the sled motor by one step when the disk rotation speed reaches the threshold value, It is good to make it function as. By adopting such a configuration, it is possible to prevent the hypersensitive reaction of the thread driving means due to the eccentricity of the optical disk without incorporating a DSP dedicated to the thread adjustment into the optical disk apparatus, and to provide sufficient responsiveness of the thread position adjustment. By securing it, it becomes possible to improve the recording / reproducing accuracy of information. Therefore, it is possible to reduce the manufacturing cost of the optical disc apparatus and to change the control method easily because only the software needs to be replaced when changing the thread adjustment control method.
[0016]
Further, the control program configured as described above drives the system controller by a predetermined amount of tracking drive signal detection means for detecting a tracking drive signal for causing the beam focusing point of the pickup to follow the track of the optical disc, and the thread motor. The track pitch of the optical disc is calculated from the amount of change in the tracking drive signal obtained when the optical disc is rotated and the amount of change in the tracking drive signal obtained when the optical disc is rotated with the sled motor stopped. It may be configured to function as a track pitch calculation means. By adopting such a configuration, it is possible to further improve the thread feeding accuracy by calculating the track pitch of the optical disk one by one and performing the thread drive determination using the calculated value. It becomes.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing an embodiment of an optical disc apparatus according to the present invention. An optical disk apparatus 1 that performs recording / reproduction of the optical disk X is referred to as a pickup 2, a thread motor 3 (configured by a stepping motor), a spindle motor 4, and a high-frequency processing circuit 5 (hereinafter referred to as an RF [Radio Frequeny] processing circuit 5). ), An analog / digital converter 6 (hereinafter referred to as ADC [Analog / Digital Converter] 6), a signal processing circuit 7, a system controller 8, and a digital servo processing circuit 9 (mainly DSP [Digital Signal Processor]. ], Hereinafter referred to as DSP 9), PWM [Pulse Width Modulation] signal generation circuit 10, PWM driver 11, low-pass filter 12 (hereinafter referred to as LPF [Low Pass Filter] 12), spindle And a motor driver 13.
[0018]
The optical disk X is an information recording medium such as a magneto-optical disk or a phase change disk, and information is recorded along spiral or concentric tracks. When the optical disk X is a magneto-optical disk, at the time of the recording operation, the recording surface (magnetic film) uniformly magnetized in advance is irradiated with a laser beam, and the film temperature is locally raised to near the Curie point, A magnetic field corresponding to the recorded information is externally applied to the irradiated portion (portion where the coercive force is lost). As a result, the magnetic film is magnetized in the magnetic field direction and information is recorded. In the erasing operation, an erasing magnetic field opposite to the recording magnetic field is applied while the laser beam is continuously irradiated. The reproduction of the magneto-optical disk is performed using the Kerr effect in which the deflecting surface of the reflected light is slightly rotated according to the magnetization direction.
[0019]
Further, when the optical disc X is a phase change disc, the recording operation is performed using the characteristic that the multi-element material reversibly changes between crystalline and amorphous. That is, during the recording operation of the phase change disk, the recording surface (multi-element material film) is irradiated with a laser beam, the film temperature is rapidly heated to the melting point or more locally, and then the irradiated part is rapidly cooled. As a result, an amorphous phase corresponding to the recording information is formed on the recording surface and information is recorded. Further, at the time of erasing operation, the recording surface is gradually heated and cooled at a temperature not lower than the crystallization temperature and not higher than the melting point by the laser beam to return the amorphous phase to the crystalline phase. The phase change disk is reproduced by detecting a change in the amount of reflected light in view of the difference in reflectance between the crystalline phase (high reflectance) and the amorphous phase (low reflectance).
[0020]
The pickup 2 is means for recording and reproducing information on the optical disc by irradiating the optical disc X with laser light. The pickup 2 detects two photodetectors (RF signals) for detecting reflected light returning from the optical disc X. And a second optical detector for detecting a tracking error signal and a focus error signal (both not shown), and the optical detection signals obtained by these are both RF It is sent to the processing circuit 5 and subjected to IV conversion (current signal → voltage signal). The pickup 2 includes an LD driver (not shown) that performs pulse generation at the time of pulse emission and laser power control.
[0021]
The photodetection signal corresponding to the RF signal is composed of two signals whose phases are opposite to each other, and the RF processing circuit 5 obtains a difference signal (substantially a sum signal) of both signals, and AGC [Automatic Gain Control] Processing is performed. The processed signal is sent to the signal processing circuit 7 and then subjected to error correction, deinterleaving, NRZI (Non Return to Zero Invert) conversion, Viterbi decoding, and the like. In addition to the above signal processing, the signal processing circuit 7 also generates a spin error signal based on a spindle rotation signal (FG [Frequency Generator] pulse) generated by the spindle motor driver 13. The spin error signal is sent to the DSP 9.
[0022]
On the other hand, a light detection signal corresponding to the error signal is also sent to the RF processing circuit 5, and the RF processing circuit 5 generates error signals for tracking and focusing. The generated error signal is converted into a digital signal by the ADC 6 and then sent to the DSP 9. In the DSP 9, a final error signal is generated based on the digital signal input from the ADC 6. The generated final error signal is equalized by the phase compensation circuit and then sent to the PWM signal generation circuit 10. Here, the final error signal converted into PWM is used as an actuator drive signal (tracking drive signal and focus drive signal) via the PWM driver 11, and the tracking actuator 21 and the focus actuator for driving the objective lens provided in the pickup 2. 22 is sent out. Both actuators 21 and 22 perform posture control of an objective lens (not shown) based on the tracking drive signal and the focus drive signal input from the PWM driver 11.
[0023]
The spin error signal input from the signal processing circuit 7 to the DSP 9 is also equalized by the phase compensation circuit, and then sent to the PWM signal generation circuit 10. Here, the PWM spin error signal is converted into a spindle drive signal via the spindle motor driver 13 and sent to the spindle motor 4. The spindle motor 4 rotates the optical disc X at a constant linear velocity based on the spindle drive signal input from the spindle motor driver 13.
[0024]
A system controller 8 that controls the entire control of the system includes a control unit 81 that controls the signal processing circuit 7 and the DSP 9 as necessary, and a tracking drive signal detection unit 82 that detects a tracking drive signal input via the LPF 12. A rotation monitoring means 83 for detecting a spindle rotation signal (FG pulse) generated by the spindle motor driver 13; and a track pitch for calculating a track pitch based on both outputs of the tracking drive signal detection means 82 and the rotation monitoring means 83. The calculation means 84, and the thread drive determination means 85 for determining whether or not the thread drive is possible based on both outputs of the rotation monitoring means 83 and the track pitch calculation means 84 are provided. The track pitch calculation and sled drive determination will be described in detail later.
[0025]
In the optical disk apparatus 1 having the above configuration, for example, when the sled motor 3 is moved by a specified distance, the system controller 8 issues a control command to the DSP 9 from the control means 81, and the DSP 9 that receives the control command 3 control signals are generated. The generated control signal is sent to the PWM signal generation circuit 10. Here, the PWM control signal is converted into a thread drive signal via the PWM driver 11 and sent to the thread motor 3. The sled motor 3 is driven based on a sled drive signal input from the PWM driver 11, and the pickup 2 is connected to the optical disc X via intermediate transmission means (not shown) that converts the rotational drive of the sled motor 3 into linear drive. The thread is moved in the radial direction.
[0026]
The above-described drive control of the thread motor 3 will be described in more detail with reference to FIGS. FIG. 2 is a block diagram showing in detail the drive control unit of the sled motor 3, and FIG. 3 is a waveform diagram showing a sled drive signal.
[0027]
As shown in FIG. 2, when the thread motor 3 is driven, a control command is first issued from the system controller 8 to the DSP 9. In the DSP 9 that has received the command, the thread motor control signals SLIN 1 and SLIN 2 (see FIG. 3) are generated using the thread feed control means 91, and both control signals are sent to the PWM signal generation circuit 10. Here, both control signals converted into PWM are converted into thread drive signals via the PWM driver 11 and sent to the A phase and B phase of the thread motor 3.
[0028]
As a feed control method of the thread motor 3, a full step drive system, a half step drive system, a micro step drive system, and the like are generally used. In FIG. 2 shows signal waveforms in the case of half-step driving. As can be seen from this figure, the half-step drive method achieves twice the feed accuracy with respect to the full-step drive method. That is, if the feed amount of one step in the full step drive is 150 [μm], the one step feed amount of the half step drive method is 75 [μm]. Further, although not shown in the figure, the microstep drive system further improves the feeding accuracy. For example, when a feed accuracy of 128 times that of the full-step drive system is realized, the feed amount is 4.68 [μm]. The above-mentioned feed amount is an example of a set value that is usually used.
[0029]
Next, thread feed control, which is a characteristic part of the present invention, will be described in detail. FIG. 4 is a waveform diagram for explaining thread feed control according to the present invention. As shown in this figure, the tracking drive signal generated by the PWM driver 11 is obtained by adding the eccentric component (AC component) of the optical disc X to the DC component that fluctuates according to the inclination (deviation) of the tracking direction of the pickup 2. Signal. On the other hand, the output signal of the LPF 12 is a signal obtained by removing the eccentric component (AC component) from the tracking drive signal, that is, the neutral state of the tracking actuator 21 (the objective lens exists at the center position within the adjustment range of the tracking actuator 21). The center value of the tracking drive signal in the state). As described above, in the optical disc apparatus 1 of the present embodiment, unlike the conventional configuration, the thread feed control is performed using the tracking drive signal via the LPF 12 instead of the tracking error signal, so that the influence of the eccentric component of the optical disc X is affected. Highly accurate feed control can be realized with almost no impact. The spindle rotation signal (FG pulse) is a rectangular pulse signal that is output 6 pulses per rotation of the optical disc X.
[0030]
Consider a case where the reproducing operation of the optical disc X is performed without threading the pickup 2. In such a case, the track to be followed deviates in the radial direction from the in-focus position of the pickup 2 by the track pitch every time the optical disk X rotates once (six spindle rotation signals are detected). By utilizing such a relationship, it is possible to determine whether or not thread driving is possible based on the spindle rotation signal (FG pulse).
[0031]
For example, when the sled motor 3 is driven by the half-step drive method (1 step feed amount: 75 [μm]) with respect to the optical disc X whose track pitch standard value is 0.375 [μm / rotation] Detects when the optical disk X is rotated 200 times (= 75 [μm] ÷ 0.375 [μm / rotation]), that is, the spindle rotation signal is 1200 pulses (= 200 [rotations] × 6 [pulses / rotation]). When this is done, the thread motor 3 need only be sent one step.
[0032]
However, if the value of the standard track pitch (0.375 [μm / rotation] in the above example) is used as it is when calculating the threshold value of the spindle rotation signal, there is an error between the standard value and the actual value. An accurate threshold value cannot be calculated, and the thread feed accuracy is slightly reduced. Therefore, in order to further improve the thread feeding accuracy, the optical disc apparatus 1 according to the present invention calculates the track pitch of the optical disc X by the track pitch calculation unit 84 one by one, and uses the calculated value to set the threshold value of the spindle rotation signal. The configuration is as desired.
[0033]
FIG. 5 is a flowchart showing the track pitch calculation operation of the optical disc X. When insertion of the optical disk X is detected in step S101, rotation of the optical disk X is started in step S102. When the rotational speed reaches a predetermined value, the laser irradiation, focus servo, and tracking servo of the pickup 2 are turned on in steps S103 to S105.
[0034]
Thereafter, in step S106, the pickup 2 is paused at the designated position, and in step S107, the output signal of the LPF 12 at that time (hereinafter referred to as LPF signal A) is taken into the tracking drive signal detector 82. Next, in step S108, the sled motor 3 is sent by one step (for example, 75 [μm]) in the minus direction by the half-step drive method, and the output signal of the LPF 12 (hereinafter referred to as LPF signal B) is again in step S109. Is captured by the tracking drive signal detection means 82. Based on the LPF signals A and B, in step S110, the tracking drive signal change amount V1 (= A−B) per step in the half-step drive method is calculated. In the subsequent step S111, the sled motor 3 is sent one step in the plus direction by the half-step driving method of the pickup 2, and the pickup position is returned to the initial state.
[0035]
Next, in step S112, the playback operation is started with the sled motor 3 stopped, and the spindle rotation signal threshold value (preliminarily calculated using a standard track pitch (0.375 [μm / rotation]) ( In the present embodiment, 1200 [pulse] = 75 [μm] ÷ 0.375 [μm / rotation] × 6 [pulse / rotation]) is detected by the rotation monitoring means 83, and the output signal of the LPF 12 is detected in step S113. (Hereinafter, referred to as a standard tracking drive signal change amount V2) is taken into the tracking drive signal detection means 82.
[0036]
Here, the correlation shown in FIG. 6 is present between the tracking drive signal change amount and the thread feed amount (V1: V2 = 75 [μm]: true track pitch p [μm / rotation] × 200 [rotation]). In step S114, the true track pitch p [μm / rotation] is calculated based on the following equation (1).
p = (75 × V2) / (200 × V1) (1)
[0037]
For example, when V1 = 1.00 [V] and V2 = 0.95 [V], the true track pitch p = 0.356 [μm] is calculated.
[0038]
Based on the above description, an operation flow of thread feed control according to the present invention will be described. FIG. 7 is a flowchart showing the thread feed control operation according to the present invention. In step S201, a one-step thread feed amount (75 [μm] in this embodiment) is set in consideration of the trace performance of the pickup 2 and the thread motor driving method. After the setting is completed, in step S202, the track pitch calculation result (0.356 [μm / rotation] in the present embodiment) obtained by the track pitch calculation means 84 is obtained, and in step S203, the thread feed amount is changed to the spindle rotation signal. It is converted into the number of pulses of (FG pulse). The calculated number of pulses (in this embodiment, 1264 [pulse] = 75 [μm] ÷ 0.356 [μm / rotation] × 6 [pulse / rotation]) is determined by the thread drive determination means 85 in step S204. It is set as a threshold for determining whether or not a thread can be driven.
[0039]
After the above setting, the reproduction operation of the optical disk X is started in step S205, and the spindle rotation signal (FG pulse) is started in step S206. Thereafter, when 1264 [pulses] of the spindle rotation signal (FG pulse) is detected, in step S207, the thread drive determination unit 85 makes a thread drive permission determination, and the control unit 81 sends a thread to the DSP 9 according to the determination result. A feed instruction for the motor 3 is issued. With such an operation, the sled motor 3 is sent one step in the plus direction by the half-step drive method.
[0040]
As described above, in the optical disc apparatus 1 of the present embodiment, the tracking drive and the sled drive can be independently controlled, so that the hypersensitive reaction of the sled drive means due to the eccentricity of the optical disc is prevented, and the sled position It is possible to improve the recording / reproducing accuracy of information by ensuring sufficient adjustment responsiveness.
[0041]
Finally, the tracking gain correction operation in the optical disc apparatus 1 of the present embodiment will be described in detail. FIG. 8 is a flowchart showing the tracking gain correction operation of the present invention. This correction operation flow is a routine that is inserted between step S206 and step S207 constituting the above-described thread feed control flow (see FIG. 7) and is continuously performed during the reproducing operation of the optical disc X.
[0042]
In the tracking gain correction operation, in step S301, the tracking drive signal is detected every time the spindle rotation signal (FG pulse) is detected 1264 [pulses], and in step S302, the tracking drive signal change amount is calculated. Is done. In step S303, the current calculated value and the previous calculated value are compared, and tracking gain correction is performed based on the comparison result. With such a configuration, the tracking gain is always corrected even during reproduction of the optical disc X, so that it is possible to further improve the accuracy of tracking drive control and sled drive control.
[0043]
The tracking drive signal detection means 82, the rotation monitoring means 83, the track pitch calculation means 84, and the thread drive determination means 85 are configured as software developed in the system controller 8 including the control means 81 or in the DSP 9. Good. Thus, by configuring each means 82 to 85 as software, it is not necessary to incorporate a DSP or the like dedicated for thread adjustment into the optical disk apparatus, so that the manufacturing cost of the optical disk apparatus can be reduced and thread adjustment control is performed. Even when the method is changed, it is only necessary to replace the software, so that the control method can be easily changed.
[0044]
【The invention's effect】
As described above, the optical disc apparatus and the control program thereof according to the present invention can prevent the hypersensitive reaction of the sled driving means due to the eccentricity of the optical disc, and sufficiently ensure the responsiveness of the sled position adjustment. Therefore, it is possible to improve the recording / reproducing accuracy of information.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an embodiment of an optical disc apparatus according to the present invention.
FIG. 2 is a block diagram showing in detail a drive control unit of the sled motor 3. FIG.
FIG. 3 is a waveform diagram showing a sled drive signal.
FIG. 4 is a waveform diagram for explaining thread feed control according to the present invention.
FIG. 5 is a flowchart showing a track pitch calculation operation of the present invention.
6 is a diagram for explaining a correlation established between tracking drive signal change amounts V1 and V2 and a thread feed amount. FIG.
FIG. 7 is a flowchart showing a thread feed control operation according to the present invention.
FIG. 8 is a flowchart showing a tracking gain correction operation of the present invention.
[Explanation of symbols]
1 Optical disk device
2 Pickup
21 Tracking actuator
22 Focus actuator
3 Thread motor
4 Spindle motor
5 High-frequency processing circuit (RF processing circuit)
6 Analog / digital converter (ADC)
7 Signal processing circuit
8 System controller
81 Control means
82 Thread drive determination means
83 Track pitch calculation means
84 Tracking drive signal detection means
85 Rotation monitoring means
9 Digital servo processing circuit (DSP)
91 Thread feed control means
10 PWM signal generation circuit
11 PWM driver
12 Low-pass filter (LPF)
13 Spindle motor driver
X optical disc

Claims (4)

A pickup that irradiates the optical disc with a beam and detects the reflected light; a spindle motor that rotates the optical disc; and a sled motor that moves the pickup in the radial direction of the optical disc. In an optical disc apparatus for recording and / or reproducing information,
A rotation monitoring means for monitoring the disk rotation speed, a disk rotation speed corresponding to the one-step feed amount from the one-step feed amount of the sled motor and the track pitch of the optical disk, and a threshold value. Based on the determination result of the sled drive determination means and the sled drive determination means for comparing the disk rotation speed obtained by the rotation monitoring means to determine whether the sled motor can be driven, the disk rotation speed reaches the threshold value. Control means for sending the sled motor by one step, tracking drive signal detecting means for detecting a tracking drive signal for causing the beam focus of the pickup to follow the track of the optical disc, and a predetermined amount of the sled motor. The amount of change in the tracking drive signal obtained when only the The optical disk from a change amount of the tracking drive signal obtained when rotating in a state in which the thread motor is stopped, the track pitch calculation means for calculating a track pitch of the optical disc, and characterized in that it comprises a Optical disk device to perform. 2. The optical disc apparatus according to claim 1, further comprising a low-pass filter that selectively passes only a low frequency component of the tracking drive signal to the tracking drive signal detection means . The tracking drive signal detecting means detects a tracking drive signal in a timely manner during the reproduction of the optical disc, calculates a change amount thereof, and performs tracking gain correction based on a comparison result between the calculated value and the previous calculated value. The optical disc apparatus according to claim 2. A pickup that irradiates the optical disc with a beam and detects reflected light; a spindle motor that rotates the optical disc; a sled motor that moves the pickup in the radial direction of the optical disc; and a system controller that controls the system. In a control program for functioning an optical disc apparatus that records and / or reproduces information on the optical disc,
  The system controller is a rotation monitoring means for monitoring the number of rotations of the disk, a one-step feed amount of the sled motor and a track pitch of the optical disc, and a disk revolution number corresponding to the one-step feed amount is obtained as a threshold value. Based on the determination result of the thread drive determination means, the disk rotation speed is determined based on the determination result of the thread drive determination means by comparing the threshold value with the disk rotation speed obtained by the rotation monitoring means. Control means for sending the sled motor by one step when a threshold value is reached, tracking drive signal detecting means for detecting a tracking drive signal for causing the beam focus of the pickup to follow the track of the optical disc, and the sled motor Obtained by driving a predetermined amount of A track pitch calculating means for calculating a track pitch of the optical disc from a change amount of the tracking drive signal obtained by rotating the optical disc while the sled motor is stopped. Control program to let you.

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