JP4670815B2 - Optical disc apparatus and control method thereof - Google Patents

Description

  The present invention relates to an optical disc apparatus that performs at least one of recording and reproduction of information on an optical disc and a control method thereof.

  A drive current supplied from a drive unit that drives an objective lens in a conventional optical disc apparatus will be described.

  When tracking control is stopped in the optical disc apparatus, the laser beam emitted from the objective lens does not follow the information track of the optical disc and crosses the information track. At this time, the reflected light from the optical disc becomes a laser beam in which the balance of light and darkness in the light beam changes remarkably. Since the focus error signal is also generated from the laser beam whose balance of light and dark changes significantly, the waveform is more distorted than during tracking control. Since the focus drive signal for driving the objective lens in the focus direction is generally generated by amplifying particularly the high frequency component of the focus error signal, if the waveform of the focus error signal is disturbed while tracking control is stopped, The amplitude of the focus drive signal is further amplified and increased, and the drive unit that drives the objective lens flows a larger current than necessary while the tracking control is stopped.

  The drive current supplied from the drive unit that drives the objective lens when an optical disk with large surface wobbling is mounted on such a conventional optical disk apparatus will be described with reference to FIG.

  FIG. 9 is a diagram showing a tracking drive signal in a conventional optical disc apparatus. 9, (a) shows the position of the objective lens 5 in the focus direction, (b) shows the focus drive signal during tracking control, (c) shows the focus drive signal when tracking control is stopped, d) shows the limited focus drive signal when the tracking control is stopped.

  When the optical disc 1 having a surface shake that varies in height during one rotation is mounted on the optical disc apparatus, the position of the objective lens 5 in the focus direction is information on the optical disc 1 as shown in FIG. Moves up and down during one rotation following the recording surface.

  For this reason, as shown in FIG. 9B, the focus drive signal during the tracking control has a minute fluctuation component generated due to a deviation between the information recording surface of the optical disk 1 and the focus of the objective lens 5, as shown in FIG. The signal fluctuates so as to swell greatly in the vertical direction due to surface wobbling.

  On the other hand, since the focus error signal while tracking control is stopped is generated from reflected light whose brightness balance changes significantly across the information track, the waveform is disturbed. The focus drive signal is generated by amplifying the high frequency component of the focus error signal as described above. As a result, the focus drive signal during the stop of the tracking control has an amplitude of a minute fluctuation component generated due to a deviation between the information recording surface of the optical disc 1 and the focus of the objective lens 5 as shown in FIG. 9C. The increased signal becomes a signal that fluctuates up and down due to the shake of the surface of the optical disk 1 as in the tracking control, and the drive unit that drives the objective lens 1 passes a larger current than necessary. .

Conventionally, there has been a technique of limiting the drive current supplied to the actuator to a predetermined value based on the limit current stored in the storage unit to reduce power consumption (see, for example, Patent Document 1).
JP 08-265960 A

  However, the above-described conventional optical disk apparatus has the following problems.

  In other words, when the drive current supplied to the actuator that drives the objective lens is limited to a predetermined value based on the limit current stored in the storage unit, when an optical disc with a large surface shake is mounted on the optical disc apparatus, the focus drive signal There is a possibility that the portion necessary for following the information recording surface of the objective lens is limited, and the objective lens cannot follow the information recording surface of the optical disc.

  However, since the focus drive signal does not limit the part necessary for tracking, as shown in FIG. 9B, during tracking control in which the laser beam emitted from the objective lens follows the information track of the optical disk. Then, the maximum value FODmax and the minimum value FODmin of the focus drive signal are detected, and a margin is provided. As shown in FIG. 9D, tracking during stoppage of tracking control is performed with FODmax + c and FODmin-c as limit values. Even if the control signal is limited, only the portion above the FODmax + c and the portion below the FODmin-c are removed from the focus drive signal indicated by the broken line in FIG. However, the power consumption cannot be reduced.

  Accordingly, the present invention has been made in view of the above-described problems, and an optical disc apparatus and a control method thereof that can appropriately reduce power consumption even when an optical disc to be mounted has a large surface shake. The purpose is to provide.

  The present invention has been made to solve the above problem, and calculates a limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal based on the focus drive signal during tracking control. The servo processing unit generates a focus drive signal by removing a signal component of the focus drive signal exceeding a predetermined width indicated by the limit value while the tracking control is stopped.

  In the present invention, even if the optical disk has a large surface shake, the limit value is set along the waveform of the rotation frequency component generated by the optical disk surface shake in the focus drive signal. Electric power can be reduced.

  In order to solve the above-described problem, an optical disc apparatus according to claim 1 includes a signal processing unit that generates a servo error signal based on reflected light from an optical disc, and a focus drive signal and a tracking drive signal based on the servo error signal. A servo processing unit to be generated, a detection unit for detecting the rotational frequency component of the optical disc from the focus drive signal, and a drive for performing focus control of the objective lens based on the focus drive signal and performing tracking control of the objective lens based on the tracking drive signal And a control unit that calculates a limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal based on the focus drive signal during tracking control, and sets the limit value in the servo processing unit. The servo processing unit is a predetermined value indicated by the limit value while the tracking control is stopped. By removing the signal components of the focus drive signal exceeding and generates a focus drive signal.

  According to the present invention, during tracking control, a limit value indicating a predetermined width along the focus drive signal waveform is calculated based on the focus drive signal and set in the servo processing unit, and the servo processing unit stops tracking control. By generating a focus drive signal by removing the signal component of the focus drive signal that exceeds a predetermined width indicated by the limit value, the focus drive signal when tracking control is stopped traverses the information track unless it is limited. Although the amplitude increases due to the influence of the laser beam, by limiting the amplitude of the focus drive signal that is unnecessary for focus control, the drive unit that drives the objective lens does not flow more current than necessary. The power consumption when tracking control is not performed can be reduced.

  Further, by calculating a limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal and setting it in the servo processing unit, even if the optical disc has a large surface blur, the focus drive Since the limit value is set along the waveform of the rotation frequency component generated due to the surface shake of the optical disk in the signal, the power consumption can be appropriately reduced.

  According to a second aspect of the present invention, in the optical disc apparatus of the first aspect, the detection unit includes a band pass filter that includes the rotation frequency of the optical disc in the pass band, and the band pass filter detects the focus drive signal. The rotational frequency component of the optical disk is detected.

  According to the present invention, the detection unit includes a band-pass filter that includes the rotation frequency of the optical disk in the pass band, and the band-pass filter detects the rotation frequency component of the optical disk from the focus drive signal in the band-pass filter. Since the rotation frequency component of the optical disc can be detected from the focus drive signal simply by providing a filter and inputting the focus drive signal, the rotation frequency component of the focus drive signal used for calculating the limit value of the focus drive signal with a simple configuration Can be detected.

  An optical disk device according to a third aspect is the optical disk device according to the second aspect, further comprising a high-pass filter whose pass band is a frequency band higher than the rotational frequency of the optical disk. A frequency component higher than the rotational frequency component of the optical disc is detected from the focus drive signal using a pass filter, a predetermined width is determined based on the detected fluctuation range of the high frequency component, and the focus drive signal is detected using a band pass filter. A predetermined width is added to the detected rotational frequency component of the optical disc to calculate a limit value indicating the predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal.

  According to the present invention, the high-pass filter having a pass band that is a frequency band higher than the rotation frequency of the optical disc is provided, and the control unit uses the high-pass filter to detect the rotational frequency component of the optical disc from the focus drive signal. By detecting a high frequency component and determining a predetermined width based on the detected fluctuation range of the high frequency component, a high-pass filter is provided in the optical disc apparatus, and only a focus drive signal is input. Rotational frequency components, which are large fluctuation components caused by surface blurring, are removed, and a minute amount generated due to a deviation between the information recording surface of the optical disc and the focal point of the objective lens, which is necessary for determining a predetermined width of the focus drive signal. Since only the fluctuation component can be detected, the predetermined width can be determined with a simple configuration.

  A limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disk of the focus drive signal by adding a predetermined width to the rotational frequency component of the optical disk detected from the focus drive signal using a band pass filter. Is calculated by adding the predetermined width of the limit value for the focus drive signal determined using the high-pass filter to the rotation frequency component that is the reference for the limit value for the focus drive signal detected by the band pass filter. The limit value of the focus drive signal can be calculated with a simple configuration using two types of filters, a band pass filter and a high pass filter.

  The optical disk apparatus according to claim 4 is the optical disk apparatus according to claim 3, wherein the control unit adds a predetermined width to the rotation frequency component for each rotation phase of the optical disk, and limits the rotation for each rotation phase of the optical disk. The value is calculated.

  According to the present invention, the control unit adds a predetermined width to the rotation frequency component for each rotation phase of the optical disc, and calculates the limit value for each rotation phase of the optical disc, thereby making one rotation with the surface shake of the optical disc. Since the limit value is calculated in accordance with the state of the focus drive signal that changes within the range, the optimum limit value can always be set in the servo processing unit in accordance with the rotational phase of the optical disk.

  The optical disk apparatus according to claim 5 is the optical disk apparatus according to claim 1, wherein the detection unit includes a low-pass filter including a rotation frequency of the optical disk in a pass band, and focus driving is performed in the low-pass filter. The rotational frequency component of the optical disk is detected from the signal.

  According to the present invention, the detection unit includes the low-pass filter including the rotation frequency of the optical disk in the pass band, and the focus drive signal is detected by detecting the rotation frequency component of the optical disk from the focus drive signal in the low-pass filter. Is the rotational frequency component of the optical disk, so the rotational frequency component of the focus drive signal used to set the limit value of the focus drive signal can be detected with a simple configuration in which a low-pass filter is provided in the optical disk device. can do.

  The band pass filter cuts off the high-frequency component and low-frequency component of the focus drive signal, but the low-pass filter only cuts off the high-frequency component from the focus drive signal, so it cuts off the low-frequency component. Therefore, the calculation to be performed is unnecessary, and the calculation load on the detection unit can be reduced.

  An optical disk device according to a sixth aspect is the optical disk device according to the fifth aspect, further comprising a high-pass filter whose pass band is a frequency band higher than the rotation frequency of the optical disk. A frequency component higher than the rotational frequency component of the optical disk is detected from the focus drive signal using a pass filter, a predetermined width is determined based on the detected fluctuation range of the high frequency component, and the focus drive signal is determined using a low-pass filter. A predetermined value is added to the rotational frequency component of the optical disc detected from the above, and a limit value indicating the predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal is calculated.

  According to the present invention, the high-pass filter having a pass band that is a frequency band higher than the rotation frequency of the optical disc is provided, and the control unit uses the high-pass filter to detect the rotational frequency component of the optical disc from the focus drive signal. By detecting a high frequency component and determining a predetermined width based on the detected fluctuation range of the high frequency component, a high-pass filter is provided in the optical disc apparatus, and only a focus drive signal is input. Rotational frequency components, which are large fluctuation components caused by surface blurring, are removed, and a minute amount generated due to a deviation between the information recording surface of the optical disc and the focal point of the objective lens, which is necessary for determining a predetermined width of the focus drive signal. Since only the fluctuation component can be detected, the predetermined width can be determined with a simple configuration.

  Further, a restriction indicating a predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal by adding a predetermined width to the rotational frequency component of the optical disc detected from the focus drive signal using a low-pass filter. By calculating the value, the predetermined width of the limit value for the focus drive signal determined using the high-pass filter is added to the rotation frequency component that serves as a reference for the limit value for the focus drive signal detected by the low-pass filter. Therefore, it is possible to calculate the limit value of the focus drive signal with a simple configuration using two types of filters, a low-pass filter and a high-pass filter.

  The optical disk device according to claim 7 is the optical disk device according to claim 6, wherein the control unit adds a predetermined width to the rotation frequency component for each rotation phase of the optical disk and limits the rotation for each rotation phase of the optical disk. The value is calculated.

  According to the present invention, the control unit adds a predetermined width to the rotation frequency component for each rotation phase of the optical disc, and calculates the limit value for each rotation phase of the optical disc, thereby making one rotation with the surface shake of the optical disc. Since the limit value is calculated in accordance with the state of the focus drive signal that changes within the range, the optimum limit value can always be set in the servo processing unit in accordance with the rotational phase of the optical disk.

  The optical disk apparatus according to claim 8 is the optical disk apparatus according to claim 1, wherein the control unit calculates a limit value indicating a predetermined width at least every time a different optical disk is loaded in the optical disk apparatus. .

  According to the present invention, the control unit calculates a limit value indicating a predetermined width at least every time a different optical disk is loaded in the optical disk device, thereby limiting the focus drive signal according to the state of surface blurring that differs for each optical disk. Since a value can be set, a limit value corresponding to each optical disc can always be appropriately determined.

  The optical disk apparatus according to claim 9 is the optical disk apparatus according to claim 8, wherein the control unit at least every time a different optical disk is mounted in the optical disk apparatus, the fluctuation range of the rotational frequency component of the mounted optical disk. When the measured fluctuation width is equal to or greater than a predetermined value, a limit value indicating the predetermined width is calculated.

  According to the present invention, the control unit measures the fluctuation width of the rotational frequency component of the loaded optical disk at least every time a different optical disk is loaded in the optical disk device, and when the measured fluctuation width is equal to or greater than a predetermined value, By calculating a limit value indicating a predetermined width, the limit value is changed according to the waveform of the rotational frequency component of the optical disk only when an optical disk having a large surface shake is mounted. Since the limit value is not changed, the calculation load on the control unit can be reduced.

  The optical disk apparatus according to claim 10 is the optical disk apparatus according to claim 1, wherein the servo processing unit removes a signal component of the focus drive signal exceeding a predetermined width indicated by the limit value only when the tracking control is stopped. Thus, a focus drive signal is generated.

  If a limit value is set in the focus drive signal when a situation occurs in which the optical disk moves significantly due to an unexpected impact during tracking control, the objective lens can be driven greatly to follow the optical disk. Therefore, there is a possibility that the quality of recording and reproducing information on the optical disk is deteriorated.

  Therefore, the servo processing unit generates the focus drive signal by removing the signal component of the focus drive signal that exceeds the predetermined width indicated by the limit value only when the tracking control is stopped, thereby recording and reproducing information on the optical disc. During tracking control, no limit value is provided for the focus drive signal, so that the objective lens can be driven greatly, and the quality of recording and reproducing information on the optical disk can be kept good.

  The optical disk apparatus control method according to claim 11 generates a servo error signal based on reflected light from the optical disk, generates a focus drive signal and a tracking drive signal based on the servo error signal, and generates a focus drive signal. Detects the rotational frequency component of the optical disk from the optical disk, performs focus control of the objective lens based on the focus drive signal, performs tracking control of the objective lens based on the tracking drive signal, and performs focus control based on the focus drive signal during tracking control. A limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disk is calculated and set in the servo processing unit, and the servo processing unit drives the focus to exceed the predetermined width indicated by the limit value while tracking control is stopped. Generate focus drive signal by removing signal component of signal It is intended.

  According to the present invention, during tracking control, a limit value indicating a predetermined width along the focus drive signal waveform is calculated based on the focus drive signal and set in the servo processing unit, and the servo processing unit stops tracking control. By generating a focus drive signal by removing the signal component of the focus drive signal that exceeds a predetermined width indicated by the limit value, the focus drive signal when tracking control is stopped traverses the information track unless it is limited. Although the amplitude increases due to the influence of the laser beam, by limiting the amplitude of the focus drive signal that is unnecessary for focus control, the drive unit that drives the objective lens does not flow more current than necessary. The power consumption when tracking control is not performed can be reduced.

  Further, by calculating a limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disc in the focus drive signal and setting it in the servo processing unit, even if the optical disc has a large surface blur, the focus drive Since the limit value is set along the waveform of the rotation frequency component generated due to the surface shake of the optical disk in the signal, the power consumption can be appropriately reduced.

  An optical disc apparatus according to claim 12 is a signal processing unit that generates a servo error signal based on reflected light from an optical disc, and a servo processing unit that generates a focus drive signal and a tracking drive signal based on the servo error signal. A drive unit that performs focus control of the objective lens based on the focus drive signal and performs tracking control of the objective lens based on the tracking drive signal, and a plurality of maximum values of the focus drive signal based on the focus drive signal during tracking control Servo processing by calculating a plurality of limit values constituting the first imaginary line that fluctuates in response to a plurality of values and a plurality of limit values constituting the second imaginary line that fluctuates in response to a plurality of minimum values of the focus drive signal A servo processing unit configured to configure the first virtual line while tracking control is stopped. Removing signal components of a plurality of limit value and the focus drive signal exceeding a plurality of limit values constituting the second imaginary line to and generates a focus drive signal.

  According to the present invention, during the tracking control, the limit value constituting the first imaginary line that varies corresponding to the maximum value of the focus drive signal and the minimum value of the focus drive signal vary based on the focus drive signal. The limit value constituting the second virtual line is calculated and set in the servo processing unit, and the servo processing unit sets the limit value constituting the first virtual line and the limit constituting the second virtual line while the tracking control is stopped. By generating the focus drive signal by removing the signal component of the focus drive signal that exceeds the value, the focus drive signal while tracking control is stopped will have an amplitude due to the influence of the laser beam crossing the information track unless it is limited However, by limiting the amplitude of the focus drive signal that is unnecessary for focus control, a drive unit that drives the objective lens is required. Does not shed more current, it is possible to reduce power consumption when the tracking control is not performed.

  In addition, a plurality of limit values constituting a first virtual line that fluctuates corresponding to a plurality of maximum values of the focus drive signal and a plurality of second virtual lines that fluctuate corresponding to a plurality of minimum values of the focus drive signal. By calculating the limit value and setting it in the servo processing unit, even if the optical disc has large surface shake and the focus drive signal fluctuates up and down due to the surface shake, the signal of the focus drive signal Since the limit value along the waveform envelope is set, the power consumption can be appropriately reduced.

  The optical disk apparatus according to claim 13 is the optical disk apparatus according to claim 12, wherein the control unit configures a plurality of limit values and the second virtual line that configure the first virtual line for each rotational phase of the optical disk. A plurality of limit values are calculated.

  According to the present invention, the control unit calculates a plurality of limit values constituting the first imaginary line and a plurality of limit values constituting the second imaginary line for each rotational phase of the optical disc, thereby causing the surface blur of the optical disc. Accordingly, the limit value composed of the limit value is calculated according to the state of the focus drive signal that changes in one rotation, so that the optimum limit value is always set in the servo processing unit according to the rotation phase of the optical disk. be able to.

  The optical disk apparatus according to claim 14 is the optical disk apparatus according to claim 12, wherein the control unit includes a plurality of limit values constituting the first virtual line at least each time a different optical disk is loaded in the optical disk apparatus. A plurality of limit values constituting the second virtual line are calculated.

  According to the present invention, the control unit calculates a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line at least each time a different optical disk is loaded in the optical disk device. As a result, the limit value of the focus drive signal can be set according to the surface shake state that differs for each optical disc, so that the limit value corresponding to each optical disc can always be appropriately determined.

  The optical disk apparatus according to claim 15 is the optical disk apparatus according to claim 14, wherein the control unit varies at least every time a different optical disk is loaded into the optical disk apparatus, and the fluctuation range of the rotational frequency component of the loaded optical disk. When the measured fluctuation width is equal to or greater than a predetermined value, a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line are calculated.

  According to the present invention, the control unit measures the fluctuation width of the rotational frequency component of the loaded optical disk at least every time a different optical disk is loaded in the optical disk device, and when the measured fluctuation width is equal to or greater than a predetermined value, By calculating a plurality of limit values constituting the first imaginary line and a plurality of limit values constituting the second imaginary line, the waveform of the rotational frequency component of the optical disk is only applied when an optical disk having a large runout is loaded. The limit value is changed in accordance with the above, and the limit value is not changed for an optical disc with small surface blurring. Therefore, the calculation load of the control unit can be reduced.

  The optical disk device according to claim 16 is the optical disk device according to claim 12, wherein the servo processing unit includes a plurality of limit values and the second virtual line constituting the first virtual line only when the tracking control is stopped. The focus drive signal is generated by removing the signal component of the focus drive signal that exceeds a plurality of limit values constituting the.

  If a limit value is set in the focus drive signal when a situation occurs in which the optical disk moves significantly due to an unexpected impact during tracking control, the objective lens can be driven greatly to follow the optical disk. Therefore, there is a possibility that the quality of recording and reproducing information on the optical disk is deteriorated.

  Therefore, the servo processing unit removes the signal component of the focus drive signal that exceeds the plurality of limit values constituting the first virtual line and the plurality of limit values constituting the second virtual line only when tracking control is stopped. By generating a focus drive signal, a limit value is not set for the focus drive signal during tracking control in which information is recorded or reproduced on the optical disc, so that the objective lens can be driven to a large extent. The recording and reproduction quality of the information can be kept good.

  According to a seventeenth aspect of the present invention, there is provided a control method for an optical disc device, wherein a servo error signal is generated based on reflected light from an optical disc, a focus drive signal and a tracking drive signal are generated based on the servo error signal, and a focus drive signal is generated. The focus control of the objective lens is performed based on the tracking control signal, the tracking control of the objective lens is performed based on the tracking drive signal, and the first variable fluctuates corresponding to the plurality of maximum values of the focus drive signal based on the focus drive signal during the tracking control. A plurality of limit values constituting the virtual line and a plurality of limit values constituting the second virtual line that fluctuate corresponding to a plurality of minimum values of the focus drive signal are calculated and set in the servo processing unit. However, when the tracking control is stopped, a plurality of limit values constituting the first imaginary line and a plurality of controls constituting the second imaginary line are provided. And it generates a focus drive signal to remove signal components of the focus drive signal exceeding the value.

  According to the present invention, during the tracking control, the limit value constituting the first imaginary line that varies corresponding to the maximum value of the focus drive signal and the minimum value of the focus drive signal vary based on the focus drive signal. The limit value constituting the second virtual line is calculated and set in the servo processing unit, and the servo processing unit sets the limit value constituting the first virtual line and the limit constituting the second virtual line while the tracking control is stopped. By generating the focus drive signal by removing the signal component of the focus drive signal that exceeds the value, the focus drive signal while tracking control is stopped will have an amplitude due to the influence of the laser beam crossing the information track unless it is limited However, by limiting the amplitude of the focus drive signal that is unnecessary for focus control, a drive unit that drives the objective lens is required. Does not shed more current, it is possible to reduce power consumption when the tracking control is not performed.

  In addition, a plurality of limit values constituting a first virtual line that fluctuates corresponding to a plurality of maximum values of the focus drive signal and a plurality of second virtual lines that fluctuate corresponding to a plurality of minimum values of the focus drive signal. By calculating the limit value and setting it in the servo processing unit, even if the optical disc has large surface shake and the focus drive signal fluctuates up and down due to the surface shake, the signal of the focus drive signal Since the limit value along the waveform envelope is set, the power consumption can be appropriately reduced.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  FIG. 1 is a basic block diagram of an optical disc apparatus according to an embodiment of the present invention. In FIG. 1, 1 is an optical disk, 2 is a pickup module, 3 is a spindle motor, 4 is a lens holder, 5 is an objective lens, 6 is an actuator, 7 is a carriage, 8 is an optical pickup, 9 is a feed unit, and 10 is a feed motor. , 11 is an analog signal processing unit, 12 is a servo processing unit, 13 is a motor driving unit, 14 is a controller, 15 is a ROM, and 16 is a RAM. In FIG. 1, 101 is a pickup output signal output from the optical pickup 8 to the analog signal processing unit 11, 102 is a servo error signal output from the analog signal processing unit 11 to the servo processing unit 12, and 103 is a pickup module 2. Spindle FG signal output from the controller 14 to the controller 14, 104 a focus drive signal output from the servo processor 12 to the controller 14, 105 a control signal output from the controller 14 to the servo processor 12, and 106 a servo processor 12 Is a pickup module control signal output from the motor drive unit 13 to the motor drive unit 13, and 107 is a pickup module drive signal output from the motor drive unit 13 to the pickup module 2.

  A pickup module 2 that records and / or reproduces information on the optical disk 1 using a laser emission pattern condenses the laser on the information recording surface of the spindle motor 3 that holds and rotates the optical disk 1. An objective lens 5, a lens holder 4 that is provided so as to be movable with respect to the carriage 7, and a feed motor 10 that moves the carriage 7 on which the lens holder 4 is mounted in the radial direction of the optical disk 1. And the feed unit 9. The lens holder 4 and the carriage 7 are provided with a coil and a magnet (not shown), and an actuator 6 is configured to drive the lens holder 4 in the focus direction and the tracking direction by passing a current through the coil. The objective lens 5 is driven via the lens holder 4. The analog signal processing unit 11 generates a servo error signal 102 such as a focus error signal and a tracking error signal based on a pickup output signal 101 that is an output signal from a not-shown split optical sensor inside the optical pickup 8 to generate a servo processing unit 12. Output to. Here, the focus error signal in the servo error signal 102 indicates a deviation in the thickness direction of the optical disc 1 between the light spot and the recording surface on which the information track of the optical disc 1 is located. This is used for focus control for causing 5 to follow the focus direction. Further, the tracking error signal of the servo error signal 102 indicates a deviation in the radial direction of the optical disc 1 between the light spot and the information track of the optical disc 1, and causes the objective lens 5 to follow the information track of the optical disc 1 in the tracking direction. Used for tracking control.

  Based on the servo error signal 102 from the analog signal processing unit 11, the servo processing unit 12 outputs a pickup module control signal 106 including a focus drive signal for driving the objective lens 5 in the focus direction and a tracking drive signal for driving in the tracking direction. Generated and output to the motor drive unit 13. Further, at the time of driving limit value learning according to the embodiment of the present invention, the generated focus driving signal 104 is output to the controller 14. The servo processing unit 12 is a digital signal processing unit that performs digital signal processing.

  The motor drive unit 13, based on the pickup module control signal 106 sent from the servo processing unit 12, a focus drive current signal output to the pickup module 2 to drive the objective lens 5 in the focus direction, and the objective lens 5. To drive the objective lens 5 by generating a pickup module drive signal 107 including a tracking drive current signal output to the pickup module 2 in order to drive in the tracking direction. In other words, the motor drive unit 13 that is a driver IC drives the spindle motor 3, the actuator 6, and the feed motor 10 by passing a current based on the pickup module control signal 106 from the servo processing unit 12. Further, the motor drive unit 13 performs feed control using the low frequency component of the tracking error signal in the servo error signal 102 so that the objective lens 5 maintains a substantially neutral position. The feed unit 9 includes a feed motor 10 and a gear, a screw shaft, and the like (not shown), and the carriage 7 moves as the feed motor 10 rotates.

  The controller 14, which is a control means, receives signals from each unit such as the pickup module 2 and the servo processing unit 12, performs arithmetic processing on these signals, and sends the result (signal) of this arithmetic processing to each unit. Each part is driven and processed to control each part. The controller 14 includes at least an arithmetic processing device such as a CPU and MPU having an arithmetic function, and a storage unit such as a ROM 15 and a RAM 16. The controller 14 is a digital signal processing unit that performs digital signal processing.

  In the optical disk apparatus having the above-described configuration, the configuration of the servo processing unit 12 that is a characteristic part of the embodiment of the present invention will be described in more detail with reference to FIG.

  FIG. 2 is a detailed block diagram of the optical disk apparatus according to the first embodiment. In FIG. 2, 1201 is an AD converter, 1202 is a focus filter, 1203 is a low-pass filter, 1204 is a high-pass filter, 1205 is a limiter controller, 1206 is a RAM, 1207 is a limiter, and 1208 is a DA converter. The AD converter 1201, the focus filter 1202, the low-pass filter 1203, the high-pass filter 1204, the limiter controller 1205, the RAM 1206, the limiter 1207, and the DA converter 1208 are provided in the servo processing unit 12. Of these, the RAM 1206 is the limiter controller. 1205.

  Each signal shown in FIG. 2 will be described.

  Reference numeral 102 a denotes a focus error signal among the servo error signals 102 output from the analog signal processing unit 11 to the servo processing unit 12 described with reference to FIG. 1, and the analog signal processing unit 11 supplies the AD converter 1201 of the servo processing unit 12. Entered. The focus error signal 102a is an analog signal.

  A focus error signal 108 is output from the DA converter 1201 to the focus filter 1202. The focus error signal 108 is a digital signal.

  Reference numeral 104 a denotes a rotation frequency component of the focus drive signal 104 output from the servo processing unit 12 to the controller 14, and is output from the low-pass filter 1203 to the controller 14.

  Reference numeral 104 b denotes a high-frequency component in the focus drive signal 104 output from the servo processing unit 12 to the controller 14, and is output from the high-pass filter 1204 to the controller 14.

  Reference numeral 109 denotes a limiter control signal output from the limiter controller 1205 to the limiter 1207.

  Reference numeral 110 denotes a limited focus drive signal output from the limiter 1207 to the DA converter 1208. The limited focus drive signal 110 is a digital signal.

  Reference numeral 106 a denotes a limited focus drive signal among the pickup module control signal 106 output from the servo processing unit 12 to the motor drive unit 13 described with reference to FIG. 1, and is output from the DA converter 1208 to the motor drive unit 13. The limited focus drive signal 106a is an analog signal.

  Moreover, it demonstrates from a viewpoint of the function of each part in FIG.

  The AD converter 1201 AD-converts the focus error signal 102a, which is an analog signal, into a digital signal focus error signal 108, and outputs the focus error signal 108 to the focus filter 1202.

  The focus filter 1202 amplifies the focus error signal 108 with a predetermined frequency characteristic to generate the focus drive signal 104 and outputs the focus drive signal 104 to the low-pass filter 1203, the high-pass filter 1204, the controller 14, and the limiter 1207.

  The low-pass filter 1203 is a filter that includes the rotation frequency of the optical disc 1 in the pass band. The low-pass filter 1203 extracts the rotation frequency component 104 a that is a component of the rotation frequency band of the optical disc 1 from the focus drive signal 104 and outputs it to the controller 14. . The waveform of the rotation frequency component 104a extracted from the focus drive signal 104 is a linear waveform that slowly and greatly fluctuates with respect to the waveform of a high frequency component 104b described later.

  Here, the rotational frequency component 104a is extracted using the low-pass filter 1203. However, if the filter includes the rotational frequency of the optical disc 1 in the pass band, the rotational frequency component 104a is extracted using the band-pass filter. It can be implemented as well. In this case, the band-pass filter detects the rotational frequency component 104a of the optical disc 1 from the focus drive signal 104, thereby providing a band-pass filter in the optical disc apparatus. Therefore, the rotation frequency component 104a of the focus drive signal 104 used for calculating the limit value Xφ of the focus drive signal 104 can be detected with a simple configuration.

  On the other hand, in the present embodiment, the rotation frequency component 104a is extracted using the low-pass filter 1203 as shown in FIG.

  As described above, the low-pass filter 1203 including the rotation frequency of the optical disc 1 in the pass band is provided, and the focus drive signal is detected by detecting the rotation frequency component 104a of the optical disc 1 from the focus drive signal 104 in the low-pass filter 1203. Since the lowest AC frequency component in 104 is the rotational frequency component 104a of the optical disc 1, the focus drive signal used for setting the limit value Xφ of the focus drive signal 104 with a simple configuration in which the optical disk device is provided with the low-pass filter 1203. 104 rotational frequency components 104a can be detected.

  In addition, since the band pass filter cuts off the high frequency component and the low frequency component of the focus drive signal 104, it is necessary to calculate to cut off both components. Since only the band component is cut off, the calculation performed to cut off the low band component is unnecessary, and the calculation load in the detection unit can be reduced.

  The high-pass filter 1204 is a filter that uses a frequency band higher than the rotation frequency of the optical disc 1 as a pass band, and a high-frequency component that is a component of a frequency band higher than the rotation frequency of the optical disc 1 in the focus drive signal 104. 104 b is extracted and output to the controller 14. The waveform of the high frequency component 104b extracted from the focus drive signal 104 is a waveform that fluctuates quickly and minutely with respect to the waveform of the rotation frequency component 104a.

  The controller 14 measures the fluctuation range of the rotation frequency component 104a. If the measured fluctuation range is equal to or greater than a predetermined value, the controller 14 sets a predetermined width that includes the amplitude of the high-frequency component 104b that fluctuates quickly and slightly. It is determined from 104b. Then, the determined predetermined width is added to the rotation frequency component 104a which is a linear waveform for each rotation phase based on the spindle FG signal 103, and the limit value Xφ along the waveform of the rotation frequency component 104a is calculated. Conversely, when the measured fluctuation width is not equal to or greater than the predetermined value, a fixed limit value Xφ is calculated from the focus drive signal 104 itself. In any case, the limit value Xφ is output as a control signal 105 to the limiter controller 1205 of the servo processing unit 12.

  As described above, the high-pass filter 1204 whose pass band is a frequency band higher than the rotation frequency of the optical disc 1 is provided, and the controller 14 uses the high-pass filter 1204 to convert the rotation frequency of the optical disc 1 from the focus drive signal 104. A high-pass filter 1204 is provided in the optical disc apparatus by detecting a high-frequency component 104b, which is a higher frequency component than the component 104a, and determining a predetermined width based on the detected fluctuation range of the high-frequency component 104b. By simply inputting the drive signal 104, the rotational frequency component 104a, which is a large fluctuation component generated by the surface shake of the optical disc 1, is removed from the focus drive signal 104, and the focus drive signal 104 is necessary for determining a predetermined width. Deviation between the information recording surface of the optical disc 1 and the focal point of the objective lens 5 Can be detected only small variation component generated, it is possible to determine the predetermined width with a simple structure.

  Further, a predetermined width is added to the rotation frequency component 104a of the optical disc 1 detected from the focus drive signal 104 using the low-pass filter 1203, and the waveform of the rotation frequency component 104a of the optical disc 1 in the focus drive signal 104 is added. A high-pass filter 1204 is used as the rotation frequency component 104a that serves as a reference for the limit value Xφ for the focus drive signal 104 detected by the low-pass filter 1203 by calculating the limit value Xφ indicating the predetermined width along the line. Since the predetermined width of the limit value Xφ for the determined focus drive signal 104 is added, the limit value Xφ of the focus drive signal 104 is calculated with a simple configuration using two types of filters, a low-pass filter 1203 and a high-pass filter 1204. can do.

  In addition, the controller 14 adds a predetermined width to the rotation frequency component 104a for each rotation phase of the optical disc 1 and calculates the limit value Xφ for each rotation phase of the optical disc 1, so Since the limit value Xφ is calculated in accordance with the state of the focus drive signal 104 that changes during rotation, the optimum limit value Xφ can always be set in the servo processing unit 12 in accordance with the rotation phase of the optical disc 1.

  Further, when the fluctuation range of the rotational frequency component 104a is measured and the measured fluctuation range is equal to or larger than a predetermined value, a limit value Xφ indicating the predetermined width is calculated, whereby the optical disc 1 having a large surface shake is mounted. However, since the limit value Xφ is changed in accordance with the waveform of the rotational frequency component 104a of the optical disc 1 and the limit value Xφ is not changed for the optical disc 1 with small surface wobbling, the calculation load of the controller 14 can be reduced. .

  The limiter controller 1205 stores the limit value Xφ input from the controller 14 in the RAM 1206, and reads the limit value Xφ stored in the RAM 1206 for each rotation phase of the optical disc 1 based on the spindle FG signal 103 input from the pickup module 2. The limiter 1207 is set.

  The RAM 1206 holds the limit value Xφ input from the controller 14 in association with the rotation phase of the optical disc 11.

  The limiter 1207 generates a limited focus drive signal 110 by removing a signal component exceeding a predetermined width indicated by the limit value Xφ set in the limiter controller 1205 from the focus drive signal 104, and outputs the limited focus drive signal 110 to the DA converter 1208.

  In this way, the limit value Xφ indicating the predetermined width along the focus drive signal waveform is calculated based on the focus drive signal 104 during the tracking control and set in the servo processing unit 12, and the servo processing unit 12 performs the tracking control. By removing the signal component of the focus drive signal 104 exceeding the predetermined width indicated by the limit value Xφ during the stop of the focus control signal 110 and generating the limited focus drive signal 110, the focus drive signal 104 during the stop of the tracking control is limited. Otherwise, the amplitude increases due to the influence of the laser beam crossing the information track, but the motor drive unit that drives the objective lens 5 by limiting the amplitude of the focus drive signal 104 that is unnecessary for focus control. 13 does not pass more current than necessary, so power consumption when tracking control is not performed Can be reduced.

  Further, by calculating a limit value Xφ indicating a predetermined width along the waveform of the rotation frequency component 104a of the optical disc 1 in the focus drive signal 104 and setting it in the servo processing unit 12, the optical disc 1 has a large surface shake. However, since the limit value Xφ is set along the waveform of the rotation frequency component 104a generated by the surface shake of the optical disc 1 in the focus drive signal 104, the power consumption can be appropriately reduced.

  The DA converter 1208 DA-converts the limited focus drive signal 110 that is a digital signal input from the limiter 1207, and outputs it to the motor drive unit 13 (not shown) as an analog signal limited focus drive signal 106a.

  The removal of an unnecessary signal component of the focus drive signal 104 during the tracking control stop when the optical disc 1 having a large surface shake is mounted on the optical disc apparatus having the above configuration will be described with reference to FIG.

  FIG. 3 is a diagram illustrating each signal in the optical disc apparatus according to the first embodiment. 3, (a) shows the spindle FG signal 103, (b) shows the position of the objective lens 5 in the focus direction, (c) shows the focus drive signal 104 during tracking control, and (d) shows the rotation. The frequency component 104a is shown, (e) shows the high frequency component 104b, (f) shows the limit value Xφ of the focus drive signal 104, and (g) shows the limit focus drive signal 110 when the tracking control is stopped. .

  3A shows a spindle FG signal 103 that outputs eight pulses in one rotation, and the controller 14 makes one pulse for one rotation of the optical disk 1 mounted on the spindle motor 3. FIG. It is grasped by dividing into 16 at rising and falling. Here, the rotational phase of the 16-divided optical disc 1 is φa to φp, and represents the rotational phase of the optical disc 1 at a position facing the objective lens 5. When the optical disc 1 having a surface shake that varies in height during one rotation is mounted on the optical disc apparatus, the position of the objective lens 5 in the focus direction is information on the optical disc 1 as shown in FIG. Moves up and down during one rotation following the recording surface. For this reason, as shown in FIG. 3C, the focus drive signal 104 during the tracking control has a minute fluctuation component generated due to a deviation between the information recording surface of the optical disc 1 and the focus of the objective lens 5, as shown in FIG. The signal fluctuates so as to swell greatly up and down due to the surface shake of 1.

  In the optical disk device of the present embodiment, the rotation frequency component 104a shown in FIG. 3D is detected from the focus drive signal 104 during tracking control shown in FIG. 3C, and the rotation frequency component 104a is followed. Then, the predetermined width 2α shown in FIG. 3 (e) is set, and the limit value Xφ shown in FIG. 3 (f) is calculated. Further, this limit value Xφ is set in the servo processing unit 12, and the signal component of the focus drive signal 104 exceeding the limit value Xφ is removed while the tracking control is stopped, as indicated by a broken line in FIG. Then, the limited focus drive signal 110 indicated by the solid line in FIG.

  In this way, the limit value Xφ indicating the predetermined width 2α along the waveform of the focus drive signal 104 is calculated based on the focus drive signal 104 during tracking control and set in the servo processing unit 12, and the servo processing unit 12 By generating the limited focus drive signal 110 by removing the signal component of the focus drive signal 104 exceeding the predetermined width 2α indicated by the limit value Xφ during the stop of the tracking control, the focus drive signal 104 during the stop of the tracking control is If the restriction is not performed, the amplitude increases due to the influence of the laser beam crossing the information track, but the objective lens 5 is driven by limiting the amplitude of the focus drive signal 104 that is unnecessary for focus control. Since the motor drive unit 13 does not pass more current than necessary, the tracking control is not performed. It is possible to reduce the power consumption of.

  Further, by calculating a limit value Xφ indicating a predetermined width 2α along the waveform of the rotation frequency component 104a of the optical disc 1 in the focus drive signal 104 and setting it in the servo processing unit 12, the optical disc 1 has a large surface shake. Even so, the limit value Xφ along the waveform of the rotation frequency component 104a generated by the surface shake of the optical disc 1 in the focus drive signal 104 is set, so that the power consumption can be appropriately reduced.

  Hereinafter, the removal of unnecessary signal components of the focus drive signal 104 while tracking control is stopped when the optical disc 1 with large surface wobbling is mounted on the optical disc apparatus will be described in more detail.

  In the optical disk device of the present embodiment, as shown in FIG. 3D, the difference between the maximum value FLDmax and the minimum value FLDmin of the rotational frequency component 104a detected using the low-pass filter 1203 of FIG. When it is larger, as shown in FIG. 3E, the maximum value FHDmax and the minimum value FHDmin are detected from the high-frequency component 104b detected by using the high-pass filter 1204 in FIG. Then, a predetermined width 2α for limiting the focus drive signal 104 is calculated by providing a margin on the maximum value FHDmax side and the minimum value FHDmin side in the width from the maximum value FHDmax to the minimum value FHDmin. A case where the difference between the maximum value FLDmax and the minimum value FLDmin is not larger than the predetermined value will be described with reference to FIG.

  As described above, the high-pass filter 1204 whose pass band is a frequency band higher than the rotation frequency of the optical disc 1 is provided, and the controller 14 uses the high-pass filter 1204 to convert the rotation frequency of the optical disc 1 from the focus drive signal 104. A high-pass filter 1204 is provided in the optical disc apparatus by detecting the high-frequency component 104b, which is a higher frequency component than the component 104a, and determining the predetermined width 2α based on the detected fluctuation range of the high-frequency component 104b. Necessary for determining the predetermined width 2α of the focus drive signal 104 by removing the rotation frequency component 104a which is a large fluctuation component generated by the surface shake of the optical disc 1 from the focus drive signal 104 only by inputting the focus drive signal 104. The information recording surface of the optical disc 1 and the focal point of the objective lens 5 Since only a minute fluctuation component generated due to the deviation or the like can be detected, the predetermined width 2α can be determined with a simple configuration.

  In the optical disk apparatus according to the present embodiment, as shown in FIG. 3F, the rotation frequency component 104a detected using the low-pass filter 1203 in FIG. Are added together to calculate a limit value Xφ indicating the predetermined width 2α along the waveform of the rotation frequency component 104a for each rotation phase of the optical disc 1. For example, as shown in FIG. 3F, Xφb + = FLDφb + α is calculated as the upper limit value Xφ in the rotational phase φb, and Xφb− = FLDφb−α is calculated as the lower limit value Xφ, which is the upper limit in the rotational phase φc. The limit value Xφ is calculated as Xφc + = FLDφc + α, the lower limit value Xφ is calculated as Xφc− = FLDφc−α, the upper limit value Xφ in the rotational phase φd is calculated as Xφd + = FLDφd + α, and the lower limit value Xφ as Xφd− = FLDφd-α is calculated. In this way, the limit value Xφ that varies along the rotational frequency component 104a of the optical disc 1 is calculated.

  Thus, the predetermined frequency 2α is added to the rotation frequency component 104a of the optical disc 1 detected from the focus drive signal 104 using the low-pass filter 1203, and the rotation frequency component 104a of the optical disc 1 in the focus drive signal 104 is added. By calculating the limit value Xφ indicating the predetermined width 2α along the waveform of the high-pass filter, the rotation frequency component 104a serving as a reference for the limit value Xφ for the focus drive signal 104 detected by the low-pass filter 1203 is added to the high-pass filter. Since the predetermined width 2α of the limit value Xφ with respect to the focus drive signal 104 determined using 1204 is added, the focus drive signal 104 of the focus drive signal 104 can be obtained with a simple configuration using two types of filters, a low-pass filter 1203 and a high-pass filter 1204. The limit value Xφ can be calculated.

  Further, the controller 14 adds a predetermined width 2α to the rotation frequency component 104a for each rotation phase of the optical disk 1 and calculates a limit value Xφ for each rotation phase of the optical disk 1, thereby causing a surface shake of the optical disk 1. Since the limit value Xφ is calculated according to the state of the focus drive signal 104 that changes during one rotation, the optimum limit value Xφ can always be set in the servo processing unit 12 according to the rotation phase of the optical disc 1.

  In the present embodiment, the spindle FG signal 103 is used as means for grasping the rotational phase information of the optical disc 1. However, a clock having a frequency higher than that of the spindle FG signal 103 is generated in synchronization with the spindle FG signal 103. In addition, it is possible to grasp the rotational phase information in more detail. By calculating the limit value Xφ by adding the predetermined width 2α to the rotation frequency component 104a for each rotation phase of the optical disk 1 based on this clock, the limit value Xφ can be set more finely, and the accuracy of the limit value Xφ can be set. Can be raised.

  Further, in the optical disk device of the present embodiment, the limit value Xφ + and limit value Xφ− calculated for each rotation phase of the optical disk 1 shown in FIG. 2 is set to a limiter 1207 for limiting the focus drive signal 104 shown in FIG. 2, and a signal component greater than the limit value Xφ + and the limit value Xφ− from the focus drive signal 104 are set as indicated by a broken line in FIG. Smaller signal components are removed, and a limited focus drive signal 110 indicated by a solid line in FIG. 3G is generated.

  As described above with reference to FIG. 3, the limit value Xφ indicating the predetermined width 2α along the waveform of the focus drive signal 104 is calculated based on the focus drive signal 104 during tracking control and set in the servo processing unit 12. Then, the servo processing unit 12 generates the limited focus drive signal 110 by removing the signal component of the focus drive signal 104 exceeding the predetermined width 2α indicated by the limit value Xφ while the tracking control is stopped, thereby stopping the tracking control. If the focus drive signal 104 is not limited, the amplitude increases due to the influence of the laser beam traversing the information track, but the amplitude of the focus drive signal 104 that is unnecessary for focus control is limited. Therefore, since the motor drive unit 13 that drives the objective lens 5 does not pass more current than necessary, tracking is performed. It is possible to reduce the power consumption when the control is not performed.

  Further, by calculating a limit value Xφ indicating a predetermined width 2α along the waveform of the rotation frequency component 104a of the optical disc 1 in the focus drive signal 104 and setting it in the servo processing unit 12, the optical disc 1 has a large surface shake. Even so, the limit value Xφ along the waveform of the rotation frequency component 104a generated by the surface shake of the optical disc 1 in the focus drive signal 104 is set, so that the power consumption can be appropriately reduced.

  Next, the removal of unnecessary signal components of the focus drive signal 104 while tracking control is stopped when the optical disc 1 with small surface shake is mounted on the optical disc apparatus of the present embodiment will be described with reference to FIG.

  FIG. 4 is a diagram showing each signal in the optical disc apparatus of the first embodiment. 4, (a) shows the spindle FG signal 103, (b) shows the focus drive signal 104 during tracking control, (c) shows the rotation frequency component 104a, and (d) shows that tracking control is stopped. The limited focus drive signal 110 is shown.

  4A shows a spindle FG signal 103 that outputs eight pulses in one rotation, and the controller 14 makes one pulse for one rotation of the optical disk 1 mounted on the spindle motor 3. FIG. It is grasped by dividing into 16 at rising and falling. Here, the rotational phase of the 16-divided optical disc 1 is φa to φp, and represents the rotational phase of the optical disc 1 at a position facing the objective lens 5.

  In the optical disk device of the present embodiment, as shown in FIG. 4C, the difference between the maximum value FLDmax and the minimum value FLDmin of the rotational frequency component 104a detected using the low-pass filter 1203 of FIG. When it is smaller, the maximum value FODmax and the minimum value FODmin are detected from the focus drive signal 104 as shown in FIG. A margin is provided between the maximum value FODmax and the minimum value FODmin so that Xφ + = FODmax + C and Xφ− = FODmin−C, and a fixed limit value Xφ + serving as an upper limit and a fixed limit value Xφ− serving as a lower limit are calculated. For example, as shown in FIG. 4 (d), the limit value Xφ is equal to the limit value Xφ in the rotation phase φb, the limit value Xφ in the rotation phase φc, and the limit value Xφ in the rotation phase φd, and Xφb + = Xφc + = Xφd + = FODmax + C Xφb− = Xφc− = Xφd− = FODmax−C.

  As described above, the fluctuation range of the rotation frequency component 104a is measured, and when the measured fluctuation range is equal to or larger than the predetermined value, the limit value Xφ indicating the predetermined width 2α is calculated, whereby the optical disc 1 having a large surface shake is mounted. Only when the limit value Xφ is changed in accordance with the waveform of the rotational frequency component 104a of the optical disc 1 and the limit value Xφ is not changed for the optical disc 1 with small surface wobbling, the calculation load of the controller 14 is reduced. be able to.

  FIG. 5 shows the control when calculating the limit value Xφ for removing the unnecessary signal component of the focus drive signal 104 during the tracking control stop in the optical disc apparatus as described above and setting it in the servo processing unit 12 as shown in FIG. It explains using.

  FIG. 5 is a flowchart of the drive limit value learning process of the optical disc apparatus according to the first embodiment.

  In S100, the controller 14 starts the drive limit value learning process when the optical disk apparatus is activated, for example, by mounting the optical disk 1 on the optical disk apparatus. The optical disk device is activated at least when the optical disk 1 is loaded.

  As described above, the limit value Xφ indicating the predetermined width 2α is calculated at least every time a different optical disk 1 is loaded in the optical disk apparatus, so that the limit value Xφ of the focus drive signal 104 is different according to the state of surface blurring that differs for each optical disk. Therefore, the limit value Xφ corresponding to each optical disc can always be appropriately determined.

  In S101, the controller 14 rotates the spindle motor 3 on which the optical disc 1 is mounted, and starts focus control for causing the objective lens 5 to follow the focus direction with respect to the information recording surface of the optical disc 1.

  Next, in S102, the controller 14 starts tracking control for causing the objective lens 5 to follow the information track of the optical disc 1 in the tracking direction.

  Next, in S103, the controller 14 measures the rotational frequency component 104a output from the low-pass filter 1203 in a state in which tracking control is being performed. By measuring the rotational frequency component 104a, it is possible to grasp the state of surface shake of the optical disc 1.

  Next, in S104, the controller 14 measures the maximum value FLDmax and the minimum value FLDmin of the rotation frequency component 104a. If FLDmax−FLDmin, which is the difference between them, is larger than the predetermined value A, the process proceeds to S105. If it is not greater than the predetermined value A, the process proceeds to S111. Since the rotation frequency component 104a of the focus drive signal 104 indicates a change in the focus direction of the objective lens 5 with the rotation of the optical disk 1, the larger the FLDmax−FLDmin is, the more the optical disk 1 mounted on the optical disk device is rotating. It can be seen that this is an optical disc 1 with a large surface fluctuation that fluctuates greatly in the focus direction.

  Therefore, when FLDmax−FLDmin> A, it is determined that the optical disc 1 has a large surface shake, and in the processing from S105, the waveform of the rotation frequency component 104a corresponds to the surface shake of the optical disc 1. A limit value Xφ that varies along the line is calculated.

  On the other hand, if FLDmax−FLDmin> A is not satisfied, it is determined that the surface shake of the optical disc 1 is small, and in the processing from S111, as described with reference to FIG. 9, the fixed limit value Xφ regardless of the rotational frequency component 104a. Is calculated.

  First, in S105, if FLDmax−FLDmin> A in S104, the controller 14 detects the rotation frequency component 104a for each rotation phase of the optical disc 1, and stores it in the RAM 16 as FLDφ. For example, as shown in FIG. 3D, FLDφb is detected as the rotational frequency component 104a in the rotational phase φb, FLDφc is detected as the rotational frequency component 104a in the rotational phase φc, and FLDφd is detected as the rotational frequency component 104a in the rotational phase φd. Each is detected and stored in the RAM 16. Thus, the controller 14 can grasp the fluctuation of the focus drive signal 104 due to the surface shake of the optical disc 1 for each rotation phase.

  As described above, the low-pass filter 1203 including the rotation frequency of the optical disc 1 in the pass band is provided, and the focus drive signal is detected by detecting the rotation frequency component 104a of the optical disc 1 from the focus drive signal 104 in the low-pass filter 1203. Since the lowest AC frequency component in 104 is the rotational frequency component 104a of the optical disc 1, the focus drive signal used for setting the limit value Xφ of the focus drive signal 104 with a simple configuration in which the optical disk device is provided with the low-pass filter 1203. 104 rotational frequency components 104a can be detected.

  The band pass filter blocks the high frequency component and the low frequency component of the focus drive signal 104, but the low frequency filter 1203 only blocks the high frequency component from the focus drive signal 104. The calculation performed to shut off is unnecessary, and the calculation load in the detection unit can be reduced.

  Next, in S106, the controller 14 measures the high-frequency component 104b output from the high-pass filter 1204 during the tracking control. By measuring the high-frequency component 104b, the rotational frequency component 104a is removed from the focus drive signal 104, and a minute fluctuation component of the focus drive signal 104 generated due to a shift between the information recording surface and the focus of the objective lens 5 is obtained. Can be detected.

  Next, in S107, the controller 14 detects the maximum value FHDmax and the minimum value FHDmin from the high frequency component 104b measured in S106, and sets the margin to the maximum value FHDmax side in the width from the maximum value FHDmax to the minimum value FHDmin. A predetermined width 2α for limiting the focus drive signal 104 is calculated by providing (FHDmax−FHDmin) + 2C = 2α respectively on the minimum value FHDmin side.

  As described above, the high-pass filter 1204 whose pass band is a frequency band higher than the rotation frequency of the optical disc 1 is provided, and the controller 14 uses the high-pass filter 1204 to convert the rotation frequency of the optical disc 1 from the focus drive signal 104. A high-pass filter 1204 is provided in the optical disc apparatus by detecting the high-frequency component 104b, which is a higher frequency component than the component 104a, and determining the predetermined width 2α based on the detected fluctuation range of the high-frequency component 104b. Necessary for determining the predetermined width 2α of the focus drive signal 104 by removing the rotation frequency component 104a which is a large fluctuation component generated by the surface shake of the optical disc 1 from the focus drive signal 104 only by inputting the focus drive signal 104. The information recording surface of the optical disc 1 and the focal point of the objective lens 5 Since only a minute fluctuation component generated due to the deviation or the like can be detected, the predetermined width 2α can be determined with a simple configuration.

  Next, in S108, the controller 14 adds X which is half of the predetermined width 2α calculated in S107 to each of FLDφ which is the rotation frequency component 104a for each rotation phase of the optical disc 1 detected in S105, so that Xφ + = FLDφ + α. Then, a limit value Xφ + which is an upper limit of the predetermined width 2α is calculated. For example, as shown in FIG. 3 (f), Xφb + = FLDφb + α is calculated as the limit value Xφ in the rotational phase φb, Xφc + = FLDφc + α is calculated as the limit value Xφ in the rotational phase φc, and Xφd + as the limit value Xφ in the rotational phase φd. = FLDφd + α is calculated. In this way, the controller 14 calculates the limit value Xφ that varies along the rotation frequency component 104a of the optical disc 1.

  Similarly, in S109, the controller 14 subtracts half the α of the predetermined width 2α calculated in S107 from each of the FLDφ that is the rotation frequency component 104a for each rotation phase of the optical disc 1 detected in S105, and Xφ− = FLDφ. A limit value Xφ− that is a lower limit of the predetermined width 2α is calculated as −α. For example, as shown in FIG. 3F, Xφb− = FLDφb−α is calculated as the limit value Xφ in the rotational phase φb, Xφc− = FLDφc−α is calculated as the limit value Xφ in the rotational phase φc, and the rotational phase φd Xφd− = FLDφd−α is calculated as the limit value Xφ in FIG. In this way, the controller 14 calculates the limit value Xφ that varies along the rotation frequency component 104a of the optical disc 1.

  Thus, the predetermined frequency 2α is added to the rotation frequency component 104a of the optical disc 1 detected from the focus drive signal 104 using the low-pass filter 1203, and the rotation frequency component 104a of the optical disc 1 in the focus drive signal 104 is added. By calculating the limit value Xφ indicating the predetermined width 2α along the waveform of the high-pass filter, the rotation frequency component 104a serving as a reference for the limit value Xφ for the focus drive signal 104 detected by the low-pass filter 1203 is added to the high-pass filter. Since the predetermined width 2α of the limit value Xφ with respect to the focus drive signal 104 determined using 1204 is added, the focus drive signal 104 of the focus drive signal 104 can be obtained with a simple configuration using two types of filters, a low-pass filter 1203 and a high-pass filter 1204. The limit value Xφ can be calculated.

  Further, by adding a predetermined width 2α to the rotation frequency component 104a for each rotation phase of the optical disc 1 and calculating the limit value Xφ for each rotation phase of the optical disc 1, the rotation of the optical disc 1 can be performed in one rotation. Since the limit value Xφ is calculated in accordance with the state of the focus drive signal 104 that changes in the above, the optimum limit value Xφ can always be set in the servo processing unit 12 in accordance with the rotational phase of the optical disc 1.

  Next, in S110, the controller 14 outputs the limit value Xφ + calculated in S108 and the limit value Xφ− calculated in S109 to the servo processing unit 12 as the control signal 105, and is provided in the limiter controller 1205 of the servo processing unit 12. Stored in the RAM 1206. Hereinafter, limit value Xφ + and limit value Xφ− are collectively referred to as limit value Xφ.

  In S111, the controller 14 ends the drive limit value learning process when the limit value Xφ is set in the limiter controller 1205 of the servo processing unit 12 in S110.

  As described above, the limit value Xφ indicating the predetermined width 2α along the waveform of the rotational frequency component 104a of the optical disc 1 in the focus drive signal 104 is calculated and set in the servo processing unit 12, so that the optical disc 1 is greatly shaken. Even if the limit value Xφ is set along the waveform of the rotation frequency component 104a generated by the surface shake of the optical disc 1 in the focus drive signal 104, the power consumption can be appropriately reduced. .

  The calculation processing of the limit value Xφ + and the limit value Xφ− when FLDmax−FLDmin> A in S104 has been described above. Hereinafter, a calculation process of the limit value Xφ + and the limit value Xφ− in the case where FLDmax−FLDmin> A in S104 will be described.

  In S112, the controller 14 measures the focus drive signal 104 output from the focus filter 1202 when FLDmax−FLDmin> A is not satisfied in S104.

  Next, in S113, the controller 14 detects the maximum value FODmax and the minimum value FODmin as shown in FIG. 4B from the focus drive signal 104 measured in S112.

  Next, in S114, the controller 14 provides a margin for the maximum value FODmax of the focus drive signal 104 detected in S113 so that Xφ + = FODmax + C, and calculates a fixed limit value Xφ + that is an upper limit. For example, as shown in FIG. 4D, the limit value Xφ in the rotational phase φb, the limit value Xφ in the rotational phase φc, and the limit value Xφ in the rotational phase φd are equal, and Xφb + = Xφc + = Xφd + = FODmax + C. In this way, the controller 14 calculates the fixed limit value Xφ regardless of the rotation frequency component 104a of the optical disc 1.

  Next, in S115, the controller 14 provides a margin for the minimum value FODmin of the focus drive signal 104 detected in S113 so that Xφ− = FODmin−C, and calculates a fixed limit value Xφ− as a lower limit. For example, as shown in FIG. 4D, the limit value Xφ in the rotational phase φb, the limit value Xφ in the rotational phase φc, and the limit value Xφ in the rotational phase φd are equal, and Xφb− = Xφc− = Xφd− = FODmax−C. is there. In this way, the controller 14 calculates the fixed limit value Xφ regardless of the rotation frequency component 104a of the optical disc 1.

  In this way, at least every time a different optical disk 1 is loaded in the optical disk apparatus, the fluctuation width of the rotational frequency component 104a of the loaded optical disk 1 is measured, and when the measured fluctuation width is a predetermined value or more, the predetermined width 2α By calculating the limit value Xφ indicating, the optical disc 1 with small runout is changed by changing the limit value Xφ according to the waveform of the rotational frequency component 104a of the optical disc 1 only when the optical disc 1 having large runout is loaded. Since the limit value Xφ is not changed, the calculation load on the controller 14 can be reduced.

  Next, in S110, the controller 14 outputs the limit value Xφ + calculated in S114 and the limit value Xφ− calculated in S115 to the servo processing unit 12 as the control signal 105, and is provided in the limiter controller 1205 of the servo processing unit 12. Stored in the RAM 1206.

  In S111, the controller 14 ends the drive limit value learning process when the limit value Xφ is set in the limiter controller 1205 of the servo processing unit 12 in S110.

  Note that after the drive limit value learning process is finished, the limiter controller 1205 always sets the limit value Xφ in the limiter 1207 even during tracking control, and the focus drive signal 104 exceeds the predetermined width 2α indicated by the limit value Xφ. The limited focus drive signal 110 may be generated by removing the signal component. However, when a situation occurs in which the optical disc 1 moves greatly due to an unexpected impact or the like during tracking control, a limit value is set in the focus drive signal 104. If Xφ is set, the objective lens 5 cannot be driven greatly to follow the optical disc 1, and the quality of information recording and reproduction on the optical disc 1 may deteriorate. Therefore, only when the tracking control is stopped, the limiter controller 1205 sets the limit value Xφ in the limiter 1207, removes the signal component of the focus drive signal 104 exceeding the predetermined width 2α indicated by the limit value Xφ, and the limit focus drive signal 110. May be configured to generate.

  As described above, the servo processing unit 12 generates the limited focus drive signal 110 by removing the signal component of the focus drive signal 104 exceeding the predetermined width 2α indicated by the limit value Xφ only while the tracking control is stopped. During the tracking control in which information is recorded and reproduced with respect to 1, the focus drive signal 104 is not provided with the limit value Xφ, so that the objective lens 5 can be driven greatly and information can be recorded on the optical disc 1 The reproduction quality can be kept good.

(Embodiment 2)
In the following, the second embodiment of the present invention will be described with reference to the drawings, particularly with respect to differences from the first embodiment of the present invention. In the first embodiment, the limit value Xφ in which the predetermined width 2α is provided in the waveform of the rotation frequency component 104a in the focus drive signal 104 during tracking control is set, but the signal of the focus drive signal 104 itself during tracking control is set. Similarly, by setting the limit value Xφ along the waveform envelope, unnecessary signal components of the focus drive signal 104 during tracking control stop can be removed.

  FIG. 6 is a detailed block diagram of the optical disk apparatus according to the second embodiment. Note that the basic block diagram of the optical disk device according to the second embodiment is the same as that described with reference to FIG. 1 in the first embodiment, and thus the description thereof is omitted here. In FIG. 6, 1201 is an AD converter, 1202 is a focus filter, 1203 is a low-pass filter, 1205 is a limiter controller, 1206 is RAM, 1207 is a limiter, and 1208 is a DA converter. The AD converter 1201, the focus filter 1202, the low-pass filter 1203, the limiter controller 1205, the RAM 1206, the limiter 1207, and the DA converter 1208 are provided in the servo processing unit 12, and of these, the RAM 1206 is provided in the limiter controller 1205. .

  Each signal shown in FIG. 6 will be described.

  Reference numeral 102 a denotes a focus error signal among the servo error signals 102 output from the analog signal processing unit 11 to the servo processing unit 12 described with reference to FIG. 1, and the analog signal processing unit 11 supplies the AD converter 1201 of the servo processing unit 12. Entered. The focus error signal 102a is an analog signal.

  A focus error signal 108 is output from the DA converter 1201 to the focus filter 1202. The focus error signal 108 is a digital signal.

  Reference numeral 104 a denotes a rotation frequency component of the focus drive signal 104 output from the servo processing unit 12 to the controller 14, and is output from the low-pass filter 1203 to the controller 14.

  Reference numeral 109 denotes a limiter control signal output from the limiter controller 1205 to the limiter 1207.

  Reference numeral 110 denotes a limited focus drive signal output from the limiter 1207 to the DA converter 1208. The limited focus drive signal 110 is a digital signal.

  Reference numeral 106 a denotes a limited focus drive signal among the pickup module control signal 106 output from the servo processing unit 12 to the motor drive unit 13 described with reference to FIG. 1, and is output from the DA converter 1208 to the motor drive unit 13. The limited focus drive signal 106a is an analog signal.

  Moreover, it demonstrates from a viewpoint of the function of each part in FIG.

  The AD converter 1201 AD-converts the focus error signal 102a, which is an analog signal, into a digital signal focus error signal 108, and outputs the focus error signal 108 to the focus filter 1202.

  The focus filter 1202 amplifies the focus error signal 108 with a predetermined frequency characteristic to generate the focus drive signal 104 and outputs the focus drive signal 104 to the low-pass filter 1203, the controller 14, and the limiter 1207.

  The low-pass filter 1203 is a filter that includes the rotation frequency of the optical disc 1 in the pass band. The low-pass filter 1203 extracts the rotation frequency component 104 a that is a component of the rotation frequency band of the optical disc 1 from the focus drive signal 104 and outputs it to the controller 14. .

  Here, the rotational frequency component 104a is extracted using the low-pass filter 1203. However, if the filter includes the rotational frequency of the optical disc 1 in the pass band, the rotational frequency component 104a is extracted using the band-pass filter. Can be similarly implemented.

  The controller 14 measures the fluctuation range of the rotation frequency component 104a. When the measured fluctuation range is equal to or greater than a predetermined value, the controller 14 corresponds to the maximum value of the focus drive signal 104 for each rotation phase of the optical disc 1 based on the spindle FG signal 103. Thus, the limit value Xφ that varies and the limit value Xφ that varies in accordance with the minimum value of the focus drive signal 104 are calculated. Conversely, when the measured fluctuation width is not equal to or greater than the predetermined value, a fixed limit value Xφ is calculated from the focus drive signal 104 itself. In any case, the limit value Xφ is output as a control signal 105 to the limiter controller 1205 of the servo processing unit 12.

  According to the present invention, the controller 14 calculates the plurality of limit values Xφ constituting the first imaginary line and the plurality of limit values Xφ constituting the second imaginary line for each rotational phase of the optical disc 1, thereby obtaining the optical disc. Since the limit value Xφ composed of the limit value Xφ is calculated in accordance with the state of the focus drive signal 104 that changes in one rotation with one surface shake, the optimal limit is always set in accordance with the rotational phase of the optical disc 1. The value Xφ can be set in the servo processing unit 12.

  Further, when the fluctuation range of the rotation frequency component 104a is measured and the measured fluctuation range is equal to or greater than a predetermined value, a plurality of limit values Xφ constituting the first imaginary line and a plurality of limit values Xφ constituting the second imaginary line are measured. By calculating the above, only when the optical disc 1 having a large surface shake is mounted, the limit value Xφ is changed in accordance with the waveform of the rotational frequency component 104a of the optical disc 1, and for the optical disc 1 having a small surface shake, Since the limit value Xφ is not changed, the calculation load on the controller 14 can be reduced.

  The limiter controller 1205 stores the limit value Xφ input from the controller 14 in the RAM 1206, and reads the limit value Xφ stored in the RAM 1206 for each rotation phase of the optical disc 1 based on the spindle FG signal 103 input from the pickup module 2. The limiter 1207 is set.

  The RAM 1206 holds the limit value Xφ input from the controller 14 in association with the rotation phase of the optical disc 1.

  The limiter 1207 removes the signal component exceeding the limit value Xφ set in the limiter controller 1205 from the focus drive signal 104, generates the limit focus drive signal 110, and outputs it to the DA converter 1208.

  In this way, the limit value Xφ constituting the first virtual line that fluctuates corresponding to the maximum value of the focus drive signal 104 based on the focus drive signal 104 during the tracking control and the minimum value of the focus drive signal 104. The limit value Xφ constituting the fluctuating second virtual line is calculated and set in the servo processing unit 12, and the servo processing unit 12 sets the limit value Xφ constituting the first virtual line and the second value while the tracking control is stopped. By removing the signal component of the focus drive signal 104 that exceeds the limit value Xφ constituting the imaginary line and generating the limited focus drive signal 110, the focus drive signal 104 during the stop of tracking control must be limited. Although the amplitude increases due to the influence of the laser beam crossing the information track, this focus drive signal 104 is indispensable for focus control. A Limiting the amplitude size, does not shed current than necessary motor drive unit 13 for driving the objective lens 5, it is possible to reduce power consumption when the tracking control is not performed.

  Further, a plurality of limit values Xφ constituting a first virtual line that varies corresponding to a plurality of maximum values of the focus drive signal 104 and a second virtual line that varies corresponding to a plurality of minimum values of the focus drive signal 104 are displayed. By calculating a plurality of limiting values Xφ to be configured and setting them in the servo processing unit 12, the optical disc 1 has a large surface shake, and the focus drive signal 104 fluctuates up and down due to the influence of the surface shake. However, since the limit value Xφ along the envelope of the signal waveform of the focus drive signal 104 is set, power consumption can be appropriately reduced.

  The DA converter 1208 DA-converts the limited focus drive signal 110 that is a digital signal input from the limiter 1207, and outputs it to the motor drive unit 13 (not shown) as an analog signal limited focus drive signal 106a.

  The removal of an unnecessary signal component of the focus drive signal 104 during the tracking control stop when the optical disc 1 having a large surface shake is mounted on the optical disc apparatus having the above configuration will be described with reference to FIG.

  FIG. 7 is a diagram illustrating each signal in the optical disc apparatus according to the second embodiment. 7, (a) shows the spindle FG signal 103, (b) shows the position of the objective lens 5 in the focus direction, (c) shows the focus drive signal 104 during tracking control, and (d) shows the rotation. The frequency component 104a is shown, (e) shows the limit value Xφ of the focus drive signal 104, and (f) shows the limit focus drive signal 110 when the tracking control is stopped.

  7A shows a spindle FG signal 103 that outputs eight pulses in one rotation, and the controller 14 makes one pulse for one rotation of the optical disk 1 mounted on the spindle motor 3. FIG. It is grasped by dividing into 16 at rising and falling. Here, the rotational phase of the 16-divided optical disc 1 is φa to φp, and represents the rotational phase of the optical disc 1 at a position facing the objective lens 5. When the optical disc 1 having a surface shake that varies in height during one rotation is mounted on the optical disc apparatus, the position of the objective lens 5 in the focus direction is information on the optical disc 1 as shown in FIG. Moves up and down during one rotation following the recording surface. For this reason, as shown in FIG. 7C, the focus drive signal 104 during the tracking control has a minute fluctuation component generated due to a deviation between the information recording surface of the optical disc 1 and the focus of the objective lens 5, as shown in FIG. The signal fluctuates so as to swell greatly up and down due to the surface shake of 1.

  In the optical disk apparatus according to the present embodiment, as shown in FIG. 7E, the maximum value of the focus drive signal 104 is handled based on the focus drive signal 104 during tracking control shown in FIG. The limit value Xφ + constituting the first virtual line that fluctuates and the limit value Xφ− constituting the second virtual line that fluctuates corresponding to the minimum value of the focus drive signal 104 are calculated. Further, the limit value Xφ + and the limit value Xφ− are set in the servo processing unit 12 and, as indicated by a broken line in FIG. 7 (f), the limit value Xφ that constitutes the first virtual line while the tracking control is stopped. The signal component of the focus drive signal 104 that exceeds the limit value Xφ constituting the second virtual line is removed, and the limited focus drive signal 110 indicated by the solid line in FIG. 7F is generated.

  In this way, the limit value Xφ constituting the first virtual line that fluctuates corresponding to the maximum value of the focus drive signal 104 based on the focus drive signal 104 during the tracking control and the minimum value of the focus drive signal 104. The limit value Xφ constituting the fluctuating second virtual line is calculated and set in the servo processing unit 12, and the servo processing unit 12 sets the limit value Xφ constituting the first virtual line and the second value while the tracking control is stopped. By removing the signal component of the focus drive signal 104 that exceeds the limit value Xφ constituting the imaginary line and generating the limited focus drive signal 110, the focus drive signal 104 during the stop of tracking control must be limited. Although the amplitude increases due to the influence of the laser beam crossing the information track, this focus drive signal 104 is indispensable for focus control. A Limiting the amplitude size, does not shed current than necessary motor drive unit 13 for driving the objective lens 5, it is possible to reduce power consumption when the tracking control is not performed.

  Further, a plurality of limit values Xφ constituting a first virtual line that varies corresponding to a plurality of maximum values of the focus drive signal 104 and a second virtual line that varies corresponding to a plurality of minimum values of the focus drive signal 104 are displayed. By calculating a plurality of limiting values Xφ to be configured and setting them in the servo processing unit 12, the optical disc 1 has a large surface shake, and the focus drive signal 104 fluctuates up and down due to the influence of the surface shake. However, since the limit value Xφ along the envelope of the signal waveform of the focus drive signal 104 is set, power consumption can be appropriately reduced.

  Hereinafter, the removal of unnecessary signal components of the focus drive signal 104 while tracking control is stopped when the optical disc 1 with large surface wobbling is mounted on the optical disc apparatus will be described in more detail. Note that the case where the optical disk 1 with small surface shake is mounted is as described with reference to FIG. 4 in the first embodiment, and thus the description thereof is omitted here.

  In the optical disc apparatus of the present embodiment, as shown in FIG. 7D, the difference between the maximum value FLDmax and the minimum value FLDmin of the rotational frequency component 104a detected using the low-pass filter 1203 in FIG. If it is larger, the maximum value FODmax and the minimum value FODmin of the focus drive signal 104 are detected for each rotation phase of the optical disc 1 as shown in FIG. For example, as shown in FIG. 7 (e), FODmaxφb is detected as the maximum value FODmaxφ of the focus drive signal 104 in the rotation phase φb, FODminφb is detected as the minimum value FODminφ, and FODmaxφc as the maximum value FODmaxφ of the focus drive signal 104 in the rotation phase φc. FODminφc is detected as the minimum value FODminφ, FODmaxφd is detected as the maximum value FODmaxφ of the focus drive signal 104 in the rotation phase φd, and FODminφd is detected as the minimum value FODminφ. As a result, the fluctuation of the focus drive signal 104 due to the surface shake of the optical disc 1 can be grasped for each rotation phase.

  Next, a margin is provided for each of the detected maximum value FODmaxφ of the focus drive signal 104 for each rotation phase of the optical disc 1 so that Xφ + = FODmaxφ + C, and the first imaginary line that fluctuates corresponding to the maximum value of the focus drive signal 104. Is calculated as a limit value Xφ +. For example, as shown in FIG. 7E, Xφb + = FODmaxφb + C is calculated as the limit value Xφ in the rotational phase φb, Xφc + = FODmaxφc + C is calculated as the limit value Xφ in the rotational phase φc, and Xφd + as the limit value Xφ in the rotational phase φd. = FODmaxφd + C is calculated. In this way, the limit value Xφ that varies in accordance with the maximum value of the focus drive signal 104 is calculated.

  Similarly, a margin is provided for each minimum value FODminφ of the focus drive signal 104 for each detected rotation phase of the optical disc 1 so that Xφ− = FODminφ−C, and the first value fluctuates corresponding to the minimum value of the focus drive signal 104. The limit value Xφ− constituting the two imaginary lines is calculated. For example, as shown in FIG. 7E, Xφb− = FODminφb−C is calculated as the limit value Xφ in the rotational phase φb, Xφc− = FODminφc−C is calculated as the limit value Xφ in the rotational phase φc, and the rotational phase φd Xφd− = FODminφd−C is calculated as the limit value Xφ in FIG. In this way, the limit value Xφ that varies in accordance with the minimum value of the focus drive signal 104 is calculated.

  In this way, by calculating the plurality of limit values Xφ constituting the first imaginary line and the plurality of limit values Xφ constituting the second imaginary line for each rotational phase of the optical disc 1, the surface shake of the optical disc 1 is accompanied. Since the limit value Xφ composed of the limit value Xφ is calculated according to the state of the focus drive signal 104 that changes during one rotation, the optimum limit value Xφ is always set according to the rotation phase of the optical disc 1. 12 can be set.

  In the present embodiment, the spindle FG signal 103 is used as means for grasping the rotational phase information of the optical disc 1. However, a clock having a frequency higher than that of the spindle FG signal 103 is generated in synchronization with the spindle FG signal 103. In addition, it is possible to grasp the rotational phase information in more detail. By calculating the limit value Xφ by adding the predetermined width 2α to the rotation frequency component 104a for each rotation phase of the optical disk 1 based on this clock, the limit value Xφ can be set more finely, and the accuracy of the limit value Xφ can be set. Can be raised.

  Further, in the optical disc apparatus of the present embodiment, the limit value Xφ + and limit value Xφ− calculated for each rotation phase of the optical disc 1 shown in FIG. 7E are used to calculate the rotation phase of the optical disc 1 based on the spindle FG signal 103. 6 is set to a limiter 1207 for limiting the focus drive signal 104 shown in FIG. 6, and a signal component greater than the limit value Xφ + and the limit value Xφ− from the focus drive signal 104 are set as indicated by a broken line in FIG. Smaller signal components are removed, and a limited focus drive signal 110 indicated by a solid line in FIG. 7F is generated.

  As described above with reference to FIG. 7, the limit value Xφ and the focus drive signal that constitute the first virtual line that varies in accordance with the maximum value of the focus drive signal 104 based on the focus drive signal 104 during tracking control. The limit value Xφ constituting the second virtual line that fluctuates corresponding to the minimum value of 104 is calculated and set in the servo processing unit 12, and the servo processing unit 12 sets the first virtual line while tracking control is stopped. The focus drive signal while the tracking control is stopped is generated by generating the limited focus drive signal 110 by removing the signal component of the focus drive signal 104 exceeding the limit value Xφ constituting the limit value and the limit value Xφ constituting the second virtual line. If the limit is not set, the amplitude increases due to the influence of the laser beam crossing the information track. By limiting the amplitude of the size unnecessary for the waste control, the motor drive unit 13 that drives the objective lens 5 does not flow more current than necessary, thereby reducing the power consumption when the tracking control is not performed. be able to.

  Further, a plurality of limit values Xφ constituting a first virtual line that varies corresponding to a plurality of maximum values of the focus drive signal 104 and a second virtual line that varies corresponding to a plurality of minimum values of the focus drive signal 104 are displayed. By calculating a plurality of limiting values Xφ to be configured and setting them in the servo processing unit 12, the optical disc 1 has a large surface shake, and the focus drive signal 104 fluctuates up and down due to the influence of the surface shake. However, since the limit value Xφ along the envelope of the signal waveform of the focus drive signal 104 is set, power consumption can be appropriately reduced.

  FIG. 8 shows the control when the limit value Xφ for removing the unnecessary signal component of the focus drive signal 104 during the tracking control stop in the optical disc apparatus as described above is calculated and set in the servo processing unit 12. It explains using.

  FIG. 8 is a flowchart of the drive limit value learning process of the optical disc apparatus according to the second embodiment.

  In S200, the controller 14 starts the drive limit value learning process when the optical disk apparatus is activated, for example, by mounting the optical disk 1 on the optical disk apparatus. The optical disk device is activated at least when the optical disk 1 is loaded.

  In this way, the optical disk is calculated by calculating a plurality of limit values Xφ constituting the first imaginary line and a plurality of limit values Xφ constituting the second imaginary line at least every time a different optical disk 1 is loaded in the optical disk apparatus. Since the limit value Xφ of the focus drive signal 104 can be set according to the state of surface blurring that differs every time, the limit value Xφ corresponding to each optical disk can always be appropriately determined.

  In S201, the controller 14 rotates the spindle motor 3 on which the optical disc 1 is mounted, and starts focus control for causing the objective lens 5 to follow the focus direction with respect to the information recording surface of the optical disc 1.

  Next, in S202, the controller 14 starts tracking control for causing the objective lens 5 to follow the information track of the optical disc 1 in the tracking direction.

  Next, in S203, the controller 14 measures the rotational frequency component 104a output from the low-pass filter 1203 in a state in which tracking control is being performed. By measuring the rotational frequency component 104a, it is possible to grasp the state of surface shake of the optical disc 1.

  Next, in S204, the controller 14 measures the maximum value FLDmax and the minimum value FLDmin of the rotation frequency component 104a. If FLDmax−FLDmin, which is the difference between them, is larger than the predetermined value A, the process proceeds to S205. If it is not greater than the predetermined value A, the process proceeds to S209. Since the rotation frequency component 104a of the focus drive signal 104 indicates a change in the focus direction of the objective lens 5 with the rotation of the optical disk 1, the larger the FLDmax−FLDmin is, the more the optical disk 1 mounted on the optical disk device is rotating. It can be seen that this is an optical disc 1 with a large surface fluctuation that fluctuates greatly in the focus direction.

  Therefore, if FLDmax−FLDmin> A, it is determined that the optical disc 1 has a large surface shake, and the processing from S205 corresponds to the surface shake of the optical disc 1 and therefore the waveform of the rotation frequency component 104a. A limit value Xφ that varies along the line is calculated.

  On the other hand, if FLDmax−FLDmin> A is not satisfied, it is determined that the surface shake of the optical disc 1 is small, and in the processing from S209, as described with reference to FIG. 9, the fixed limit value Xφ is used regardless of the rotational frequency component 104a. Is calculated.

  First, in S205, if FLDmax−FLDmin> A in S204, the controller 14 detects the maximum value FODmax of the focus drive signal 104 for each rotation phase of the optical disc 1, and stores it in the RAM 16 as FODmaxφ. Further, the minimum value FODmin of the focus drive signal 104 is detected for each rotation phase of the optical disc 1 and stored in the RAM 16 as FODminφ. For example, as shown in FIG. 7 (e), FODmaxφb is detected as the maximum value FODmaxφ of the focus drive signal 104 in the rotation phase φb, FODminφb is detected as the minimum value FODminφ, and FODmaxφc as the maximum value FODmaxφ of the focus drive signal 104 in the rotation phase φc. FODminφc is detected as the minimum value FODminφ, FODmaxφd is detected as the maximum value FODmaxφ of the focus drive signal 104 in the rotation phase φd, and FODminφd is detected as the minimum value FODminφ, and each is stored in the RAM 16. Thus, the controller 14 can grasp the fluctuation of the focus drive signal 104 due to the surface shake of the optical disc 1 for each rotation phase.

  Next, in S206, the controller 14 provides a margin for each of the maximum values FODmaxφ of the focus drive signal 104 for each rotation phase of the optical disc 1 detected in S205, so that Xφ + = FODmaxφ + C, corresponding to the maximum value of the focus drive signal 104. Then, a limit value Xφ + constituting the first virtual line that fluctuates is calculated. For example, as shown in FIG. 7E, Xφb + = FODmaxφb + C is calculated as the limit value Xφ in the rotational phase φb, Xφc + = FODmaxφc + C is calculated as the limit value Xφ in the rotational phase φc, and Xφd + as the limit value Xφ in the rotational phase φd. = FODmaxφd + C is calculated. In this way, the controller 14 calculates the limit value Xφ that varies in accordance with the maximum value of the focus drive signal 104.

  Similarly, in S207, the controller 14 provides a margin for each minimum value FODminφ of the focus drive signal 104 for each rotation phase of the optical disc 1 detected in S205 so that Xφ− = FODminφ−C, and the focus drive signal 104 is minimized. A limit value Xφ− constituting the second imaginary line that varies in accordance with the value is calculated. For example, as shown in FIG. 7E, Xφb− = FODminφb−C is calculated as the limit value Xφ in the rotational phase φb, Xφc− = FODminφc−C is calculated as the limit value Xφ in the rotational phase φc, and the rotational phase φd Xφd− = FODminφd−C is calculated as the limit value Xφ in FIG. In this way, the controller 14 calculates the limit value Xφ that varies in accordance with the minimum value of the focus drive signal 104.

  In this way, by calculating the plurality of limit values Xφ constituting the first imaginary line and the plurality of limit values Xφ constituting the second imaginary line for each rotational phase of the optical disc 1, the surface shake of the optical disc 1 is accompanied. Since the limit value Xφ composed of the limit value Xφ is calculated according to the state of the focus drive signal 104 that changes during one rotation, the optimum limit value Xφ is always set according to the rotation phase of the optical disc 1. 12 can be set.

  Next, in S208, the controller 14 outputs the limit value Xφ + calculated in S206 and the limit value Xφ− calculated in S207 to the servo processing unit 12 as the control signal 105, and is provided in the limiter controller 1205 of the servo processing unit 12. Stored in the RAM 1206. Hereinafter, limit value Xφ + and limit value Xφ− are collectively referred to as limit value Xφ.

  In S209, when the limit value Xφ is set in the limiter controller 1205 of the servo processing unit 12 in S208, the controller 14 ends the drive limit value learning process.

  As described above, the plurality of limit values Xφ constituting the first virtual line that varies corresponding to the plurality of maximum values of the focus drive signal 104 and the second virtual value that varies corresponding to the plurality of minimum values of the focus drive signal 104. By calculating a plurality of limit values Xφ constituting the line and setting them in the servo processing unit 12, the optical disc 1 has a large surface shake, and the focus drive signal 104 fluctuates up and down due to the influence of the surface shake. However, since the limit value Xφ along the envelope of the signal waveform of the focus drive signal 104 is set, it is possible to appropriately reduce power consumption.

  The calculation processing of the limit value Xφ + and the limit value Xφ− when FLDmax−FLDmin> A in S204 has been described above. Hereinafter, a calculation process of the limit value Xφ + and the limit value Xφ− when FLDmax−FLDmin> A is not satisfied in S204 will be described.

  In S210, the controller 14 measures the focus drive signal 104 output from the focus filter 1202 when FLDmax−FLDmin> A is not satisfied in S204.

  Next, in S211, the controller 14 detects the maximum value FODmax and the minimum value FODmin as shown in FIG. 4B from the focus drive signal 104 measured in S210.

  Next, in S212, the controller 14 calculates a fixed limit value Xφ + that is an upper limit by providing a margin for the maximum value FODmax of the focus drive signal 104 detected in S211 so that Xφ + = FODmax + C. For example, as shown in FIG. 4D, the limit value Xφ in the rotational phase φb, the limit value Xφ in the rotational phase φc, and the limit value Xφ in the rotational phase φd are equal, and Xφb + = Xφc + = Xφd + = FODmax + C. In this way, the controller 14 calculates a fixed limit value Xφ regardless of the maximum value of the focus drive signal 104.

  Next, in S213, the controller 14 provides a margin for the minimum value FODmin of the focus drive signal 104 detected in S211 so that Xφ− = FODmin−C, and calculates a fixed limit value Xφ− as a lower limit. For example, as shown in FIG. 4D, the limit value Xφ in the rotational phase φb, the limit value Xφ in the rotational phase φc, and the limit value Xφ in the rotational phase φd are equal, and Xφb− = Xφc− = Xφd− = FODmax−C. is there. In this way, the controller 14 calculates a fixed limit value Xφ regardless of the minimum value of the focus drive signal 104.

  In this way, at least every time a different optical disk 1 is loaded into the optical disk apparatus, the fluctuation width of the rotational frequency component 104a of the loaded optical disk 1 is measured, and if the measured fluctuation width is greater than or equal to a predetermined value, the first virtual By calculating a plurality of limit values Xφ constituting the line and a plurality of limit values Xφ constituting the second imaginary line, the rotational frequency component 104a of the optical disc 1 can be obtained only when the optical disc 1 having a large runout is loaded. Since the limit value Xφ is changed in accordance with the waveform of FIG. 5 and the limit value Xφ is not changed for the optical disc 1 with small surface wobbling, the calculation load of the controller 14 can be reduced.

  Next, in S208, the controller 14 outputs the limit value Xφ + calculated in S212 and the limit value Xφ− calculated in S213 to the servo processing unit 12 as the control signal 105, and is provided in the limiter controller 1205 of the servo processing unit 12. Stored in the RAM 1206.

  In S209, when the limit value Xφ is set in the limiter controller 1205 of the servo processing unit 12 in S208, the controller 14 ends the drive limit value learning process.

  Note that after the drive limit value learning process is completed, the limiter controller 1205 always sets the limit value Xφ in the limiter 1207 even during tracking control, and removes the signal component of the focus drive signal 104 exceeding the limit value Xφ. The limit focus drive signal 110 may be generated, but when a situation occurs in which the optical disk 1 moves greatly due to an unexpected impact or the like during tracking control, the limit value Xφ is set in the focus drive signal 104. If this is the case, the objective lens 5 cannot be driven greatly to follow the optical disc 1, and the quality of information recording and reproduction on the optical disc 1 may deteriorate. Therefore, only when the tracking control is stopped, the limiter controller 1205 sets a plurality of limit values Xφ + constituting the first virtual line and a plurality of limit values Xφ− constituting the second virtual line in the limiter 1207, and the limit value is set. The limited focus drive signal 110 may be generated by removing signal components of the focus drive signal 104 that exceed Xφ + and the limit value Xφ−.

  In this way, the servo processing unit 12 has the focus drive signal 104 that exceeds the plurality of limit values Xφ constituting the first imaginary line and the plurality of limit values Xφ constituting the second imaginary line only when the tracking control is stopped. By generating the limited focus drive signal 110 by removing the signal component, the limit value Xφ is not provided in the focus drive signal 104 during tracking control in which information is recorded or reproduced on the optical disc 1. The objective lens 5 can be driven greatly, and the quality of recording and reproducing information on the optical disk 1 can be kept good.

  The optical disk device and the control method thereof according to the present invention can be applied to applications such as an optical disk device that needs to appropriately reduce power consumption even when the optical disk to be mounted has a large surface shake.

1 is a basic block diagram of an optical disc device according to an embodiment of the present invention. Detailed block diagram of the optical disc apparatus of Embodiment 1 The figure which shows each signal in the optical disk apparatus of Embodiment 1. The figure which shows each signal in the optical disk apparatus of Embodiment 1. Flowchart of drive limit value learning process of optical disc apparatus of Embodiment 1 Detailed block diagram of optical disc apparatus of Embodiment 2 The figure which shows each signal in the optical disk apparatus of Embodiment 2. Flowchart of drive limit value learning process of optical disc apparatus of embodiment 2 The figure which shows the tracking drive signal in the conventional optical disk apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Pickup module 3 Spindle motor 4 Lens holder 5 Objective lens 6 Actuator 7 Carriage 8 Optical pick-up 9 Feed part 10 Feed motor 11 Analog signal processing part 12 Servo processing part 13 Motor drive part 14 Controller 15 ROM
16 RAM
101 Pickup output signal 102 Servo error signal 102a Focus error signal (analog)
102b Tracking error signal 103 Spindle FG signal 104 Focus drive signal 104a Rotational frequency component 104b High frequency component 105 Control signal 106 Pickup module control signal 106a Limited focus drive signal (analog)
107 Pickup module drive signal 108 Focus error signal (digital)
109 Limiter control signal 110 Limit focus drive signal (digital)
1201 AD converter 1202 Focus filter 1203 Low-pass filter 1204 High-pass filter 1205 Limiter controller 1206 RAM
1207 Limiter 1208 DA converter

Claims (17)

A signal processing unit that generates a servo error signal based on reflected light from the optical disc;
A servo processing unit that generates a focus drive signal and a tracking drive signal based on the servo error signal;
A detection unit for detecting a rotation frequency component of the optical disc from the focus drive signal;
A drive unit that performs focus control of the objective lens based on the focus drive signal and performs tracking control of the objective lens based on the tracking drive signal;
A control unit that calculates a limit value indicating a predetermined width along the waveform of the rotation frequency component of the optical disc in the focus drive signal based on the focus drive signal during the tracking control, and sets the limit value in the servo processing unit; Comprising
The optical disc apparatus, wherein the servo processing unit generates the focus drive signal by removing a signal component of the focus drive signal exceeding a predetermined width indicated by the limit value while the tracking control is stopped. The detection unit includes a band pass filter including a rotation frequency of the optical disc in a pass band,
2. The optical disc apparatus according to claim 1, wherein a rotational frequency component of the optical disc is detected from the focus drive signal in the band pass filter. Comprising a high-pass filter whose pass band is a frequency band higher than the rotational frequency of the optical disc;
The control unit detects a frequency component higher than the rotational frequency component of the optical disc from the focus drive signal using the high-pass filter, and determines the predetermined width based on the detected fluctuation range of the high frequency component And
Adding the predetermined width to the rotational frequency component of the optical disc detected from the focus drive signal using the band pass filter;
3. The optical disk apparatus according to claim 2, wherein a limit value indicating a predetermined width along a waveform of a rotation frequency component of the optical disk is calculated from the focus drive signal. The optical disk according to claim 3, wherein the control unit calculates the limit value for each rotation phase of the optical disk by adding the predetermined width to the rotation frequency component for each rotation phase of the optical disk. apparatus. The detection unit includes a low-pass filter including a rotation frequency of the optical disc in a pass band,
2. The optical disc apparatus according to claim 1, wherein a rotation frequency component of the optical disc is detected from the focus drive signal in the low-pass filter. Comprising a high-pass filter whose pass band is a frequency band higher than the rotational frequency of the optical disc;
The control unit detects a frequency component higher than the rotational frequency component of the optical disc from the focus drive signal using the high-pass filter, and determines the predetermined width based on the detected fluctuation range of the high frequency component And
Adding the predetermined width to the rotational frequency component of the optical disc detected from the focus drive signal using the low-pass filter;
6. The optical disc apparatus according to claim 5, wherein a limit value indicating a predetermined width along a waveform of a rotation frequency component of the optical disc is calculated from the focus drive signal. The optical disk according to claim 6, wherein the control unit adds the predetermined width to the rotation frequency component for each rotation phase of the optical disk, and calculates the limit value for each rotation phase of the optical disk. apparatus. 2. The optical disk apparatus according to claim 1, wherein the control unit calculates a limit value indicating the predetermined width at least each time a different optical disk is loaded into the optical disk apparatus. The control unit measures at least a variation width of a rotational frequency component of the mounted optical disc every time the different optical disc is loaded on the optical disc apparatus, and when the measured variation width is a predetermined value or more, 9. The optical disc apparatus according to claim 8, wherein a limit value indicating a predetermined width is calculated. The servo processing unit generates the focus drive signal by removing a signal component of the focus drive signal exceeding a predetermined width indicated by the limit value only when the tracking control is stopped. The optical disk device described. Generate a servo error signal based on the reflected light from the optical disc,
Generate a focus drive signal and a tracking drive signal based on the servo error signal,
Detecting a rotation frequency component of the optical disc from the focus drive signal;
Perform focus control of the objective lens based on the focus drive signal, perform tracking control of the objective lens based on the tracking drive signal,
During the tracking control, based on the focus drive signal, a limit value indicating a predetermined width along the waveform of the rotational frequency component of the optical disc is calculated from the focus drive signal, and set in the servo processing unit,
The method of controlling an optical disc apparatus, wherein the servo processing unit generates the focus drive signal by removing a signal component of the focus drive signal exceeding a predetermined width indicated by the limit value while the tracking control is stopped . A signal processing unit that generates a servo error signal based on reflected light from the optical disc;
A servo processing unit that generates a focus drive signal and a tracking drive signal based on the servo error signal;
A drive unit that performs focus control of the objective lens based on the focus drive signal and performs tracking control of the objective lens based on the tracking drive signal;
Corresponding to a plurality of limit values constituting a first imaginary line that fluctuates corresponding to a plurality of maximum values of the focus driving signal based on the focus driving signal and a plurality of minimum values of the focus driving signal during the tracking control A control unit that calculates a plurality of limit values constituting the second virtual line that fluctuates and sets the limit value in the servo processing unit,
The servo processing unit removes a signal component of the focus drive signal that exceeds a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line while the tracking control is stopped. And generating the focus drive signal. The control unit calculates a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line for each rotation phase of the optical disc. The optical disk device described. The control unit calculates at least a plurality of limit values constituting the first imaginary line and a plurality of limit values constituting the second imaginary line each time a different optical disc is loaded into the optical disc apparatus. The optical disk device according to claim 12, wherein: The control unit measures at least a variation width of a rotational frequency component of the mounted optical disc every time the different optical disc is loaded on the optical disc apparatus, and when the measured variation width is a predetermined value or more, 15. The optical disc apparatus according to claim 14, wherein a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line are calculated. The servo processing unit outputs signal components of the focus drive signal that exceed a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line only when the tracking control is stopped. 13. The optical disc apparatus according to claim 12, wherein the focus drive signal is generated by removing the focus drive signal. Generate a servo error signal based on the reflected light from the optical disc,
Generate a focus drive signal and a tracking drive signal based on the servo error signal,
Perform focus control of the objective lens based on the focus drive signal, perform tracking control of the objective lens based on the tracking drive signal,
Corresponding to a plurality of limit values constituting a first imaginary line that fluctuates corresponding to a plurality of maximum values of the focus driving signal based on the focus driving signal and a plurality of minimum values of the focus driving signal during the tracking control A plurality of limit values constituting the second imaginary line that fluctuates and is set in the servo processing unit,
The servo processing unit removes a signal component of the focus drive signal that exceeds a plurality of limit values constituting the first virtual line and a plurality of limit values constituting the second virtual line while the tracking control is stopped. And generating the focus driving signal.

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