JP4725381B2 - Optical disk device - Google Patents

Description

  The present invention relates to an optical disk device, and more particularly to transfer control of an optical pickup.

  Conventionally, in an optical disc apparatus, a seek operation is performed by transferring an optical pickup in a radial direction of the optical disc by a stepping motor.

  5 and 6 show the configuration of the optical disc apparatus and the configuration of the transfer mechanism disclosed in the prior art described below. The optical pickup 310 has a semiconductor laser (LD), emits laser light modulated in accordance with recording data, records data on the optical disk 10, and irradiates a laser beam with reproduction power to reflect light from the optical disk 10. Is received and a reproduction signal is generated.

  The decoder 320 decodes the reproduction signal from the optical pickup 310, generates an address signal or the like, and supplies it to the control unit 330.

  The control unit 330 includes a CPU, a ROM, a RAM, and the like, and controls a seek operation. Specifically, when a seek operation command including a target address corresponding to the transfer destination of the optical pickup 310 is received from a host device such as a personal computer, the number of pulses applied to the stepping motor 100 is calculated and supplied to the controller 340. The controller 340 supplies a drive control signal to the driver 350 based on a command from the control unit 330. The driver 350 controls the rotation speed and rotation speed of the stepping motor 100 according to the drive control signal.

  As shown in FIG. 6, the stepping motor 100 is provided with a lead screw 110 in which spiral grooves are formed at a constant pitch P. The lead screw 110 is attached in parallel with the radial direction of the optical disc 10. The optical pickup 310 is arranged so as to be movable along the groove of the lead screw 110 and moves in the radial direction of the optical disk 10 by one pitch P of the lead screw 110 every time the stepping motor 100 makes one rotation.

  In such a configuration, the control unit 330 calculates the difference between the current address supplied from the decoder 320 when the seek operation is completed and the target address received from the host device when the seek operation starts, and the calculated displacement amount is When the allowable amount is exceeded, it is determined that the stepping motor 100 is out of step, and the rotation speed of the stepping motor 100 is decreased. Here, “step-out” refers to a phenomenon in which the stepping motor 100 does not rotate even when a pulse voltage is applied because the torque of the stepping motor 100 is insufficient due to an increase in the pulse frequency applied to the stepping motor 100 or the like.

JP 2003-100041 A

  However, in the problem of the transfer mechanism, not only the stepping motor 100 does not step out, but also the problem of so-called “tooth skipping” in which the optical pickup 310 and the lead screw 110 are disengaged. There is a problem that a discrepancy occurs between the current address and the current address. Note that tooth skipping is considered to occur mainly due to wear or damage of the tooth portion 310a due to operation over time or impact, vibration, or the like, and can occur in the same manner when not only the stepping motor 100 but also a DC motor is used. . Further, since tooth skipping is considered to be caused by vibration as described above, it is difficult to prevent tooth skipping simply by reducing the rotation speed of the stepping motor.

  An object of the present invention is to provide an apparatus capable of executing appropriate processing when an abnormality such as tooth skipping occurs between an optical pickup and a lead screw, thereby preventing a deviation between a target address and a current address. It is in.

The present invention includes a motor, a transfer mechanism that engages with the motor and moves the optical pickup in the radial direction of the optical disk by the rotation of the motor, and when the step-out or tooth skip occurs in the transfer mechanism, optical disks have a control means for reducing the rotational speed of the spindle motor for rotatably driving the said control means, the step-out or tooth jump does not occur in the transfer mechanism after reducing the rotational speed of the spindle motor When the number of times reaches a predetermined number, the rotational speed of the spindle motor is returned to the original rotational speed, and the rotational speed is reduced again after the rotational speed of the spindle motor is restored to the original rotational speed. When the number of repetitions reaches a second predetermined number, the rotation speed of the spindle motor is maintained in a reduced state .

Further, the present invention relates to a motor, a transfer mechanism that engages with the motor and moves the optical pickup in the radial direction of the optical disk by the rotation of the motor, and when the step-out or tooth skip occurs in the transfer mechanism. And a control means for reducing the rotational speed of the spindle motor that rotationally drives the motor and the optical disk, and the control means reduces the rotational speed of the spindle motor and reduces the rotational speed of the motor. When the number of times that the step-out or tooth skip does not occur in the transfer mechanism reaches a predetermined number later, at least one of the rotational speed of the spindle motor or the rotational speed of the motor is returned to the original rotational speed, and After returning the rotational speed of the spindle motor or the rotational speed of the motor to the original rotational speed, the spindle motor again. And wherein the number of repetitions with a reduced rotational speed or the rotational speed of the motor of the motor is maintained in a state with a reduced rotational speed of the rotational speed or the motor of the spindle motor when it reaches a second predetermined number of times To do.

  According to the present invention, when a step-out or tooth skip occurs, the rotation speed of the spindle motor is decreased, or the rotation speed of the spindle motor is decreased and the rotation speed of the motor is decreased to transfer the optical pickup. It is possible to reliably carry out and prevent wear and damage of the tooth portion due to deviation from the target address and tooth skipping.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same member as the conventional apparatus shown in FIG.

<First Embodiment>
As shown in FIG. 1, the configuration of the optical disk apparatus of this embodiment is almost the same as that of the conventional apparatus shown in FIG. 5, and a seek operation start command from a host device such as a personal computer is supplied to the control unit 330. . The controller 330 supplies a control signal to the controller 340, and the stepping motor 100 is rotationally controlled by the controller 340 and the driver 350. As shown in FIG. 6, the optical pickup 310 is connected to the lead screw 110 via the tooth portion 310 a and moves in the radial direction of the optical disc 10 by the rotation of the lead screw 110. The optical pickup 310 records data by irradiating the optical disk 10 rotated by the spindle motor 11 with a recording power laser beam or irradiates a reproducing power laser beam to reproduce the recorded data. A reproduction signal from the optical pickup 310 is supplied to the decoder 320, and the decoder 320 decodes the reproduction signal and supplies decoded data and address data to the control unit 330.

  The control unit 330 compares the address (current address) supplied from the decoder 320 after transferring the optical pickup 310 in response to a seek operation start command from the host device with the target address, It is determined whether tooth skipping has occurred. Alternatively, the control unit 330 determines whether or not step-out or tooth skip has occurred using a servo signal from the focus servo 12 that performs focus control on the optical pickup 310 based on the focus error signal FE generated from the reproduction signal of the optical pickup 310. Determine whether.

  FIG. 2 shows a processing flowchart of the present embodiment. First, when a seek operation start command is received from the host device, the tracking servo is turned off (S101), and the stepping motor 100 is driven to start macro seek (S102). Here, the macro seek refers to transferring the optical pickup 310 itself in the radial direction of the optical disc 10. On the other hand, the micro jump described later refers to moving only the objective lens in the track direction without transferring the optical pickup 310 itself. The controller 330 calculates the distance (transfer distance) from the current address until the target address given from the host device is reached, calculates the necessary number of pulses, and drives the stepping motor 100. The rotation angle of the stepping motor 100 is defined by the number of pulses, and the rotation speed is defined by the pulse frequency.

  After completing the macro seek (S103), the tracking servo is turned on again (S104). Then, the current address after completion of the macro seek is read by the decoder 320 (S105) and supplied to the control unit 330. The control unit 330 compares the current address at the completion of the macro seek supplied from the decoder 320 with the target address supplied from the host device (S106). Then, as a result of the comparison, it is determined whether or not step-out or tooth skipping has occurred during macro seeking (S107). For example, the amount of deviation between the target address and the current address is calculated, the magnitude of the calculated amount of deviation is compared with the pitch P of the lead screw 110, and if the amount of deviation is equal to or greater than the pitch P, it is determined that tooth skipping has occurred. Even if the amount is smaller than the pitch P, if it is equal to or greater than a predetermined allowable threshold (pitch P> allowable threshold), it is determined that a step-out has occurred. Of course, step-out or tooth skipping may be determined by other methods.

  If it is determined that step-out or tooth skipping has not occurred, it is determined that the macro seek operation has been completed normally, and then normal re-seek processing is executed (S108). In normal re-seek processing, macro seek is executed again according to the amount of deviation between the target address and the current address, or micro jump is executed to move only the objective lens.

  On the other hand, when it is determined that step-out or tooth skipping has occurred, the seek condition is changed and the macro seek is executed again. That is, the rotational speed (rotational speed) of the spindle motor 11 is reduced (S109). For example, when the optical disk 10 is rotationally driven by the spindle motor 11 at 8 times speed, the speed is reduced to 6 times speed or 4 times speed. The reason why the rotational speed of the spindle motor 11 is decreased is to suppress vibrations that cause step-out or tooth skipping. If the optical disk 10 has an eccentric center of gravity, the spindle motor 11 vibrates during high-speed rotation, and the vibration is transmitted to a transfer mechanism such as the optical pickup 310, the teeth portion 310a, the lead screw 110, etc., and causes step-out or tooth jump. . Therefore, if the rotation speed of the spindle motor 11 is reduced, vibration can be suppressed. Further, not only the rotation speed of the spindle motor 11 is reduced, but also the drive characteristic (profile) of the stepping motor 100 is changed from the normal profile to the low profile (S110). After changing the rotation speeds of the spindle motor 11 and the stepping motor 100, the optical pickup 310 is transferred to the innermost circumference of the optical disc 10, the address of the optical pickup 310 is reset, and the processing after S101 is executed again to perform macro seek. Try again. Alternatively, since the distance from the current address to the target address is known in S105 and S106, the macro seek is re-executed accordingly. When the macro seek is re-executed, the rotation speed of the spindle motor 11 and the rotation speed of the stepping motor 100 are reduced, so that the possibility of seeking to the target address without causing step-out or tooth skipping increases.

  FIG. 3 shows an example of a low profile in S110. The horizontal axis represents the number of pulses supplied from the driver 350, and the vertical axis represents the rotation speed of the stepping motor 100. In the figure, a is a normal profile and b in the figure is a low profile. In the normal profile, the maximum rotation speed is N1, but in the low profile, the maximum rotation speed is N2. Further, the acceleration in the low profile is smaller than that in the normal profile. Therefore, step-out or tooth skipping can be prevented by changing to a low profile.

  As described above, in this embodiment, it is determined whether or not step-out or tooth skip has occurred when macro seek is completed, and when it is determined that step-out or tooth skip has occurred, the seek condition is changed and macro seek is re-executed. Therefore, the optical pickup 310 can be reliably sought to the target address commanded from the host device. Further, it is possible to prevent the tooth portion 310a from being worn or damaged due to tooth skipping or the like.

  In this embodiment, when it is determined that step-out or tooth skipping has occurred, the rotational speed of the spindle motor 11 is decreased and the rotational speed of the stepping motor 100 is decreased. However, only the rotational speed of the spindle motor 11 is decreased. May be.

Moreover, even if the rotation speed of the spindle motor 11 is decreased, or both the rotation speed of the spindle motor 11 and the rotation speed of the stepping motor 100 are decreased and the macro seek is executed again, it is determined that the step-out or tooth skipping has occurred. In this case, the rotation speed of the spindle motor 11 is further reduced, or the rotation speed of the spindle motor 11 is reduced and the rotation speed of the stepping motor 100 is reduced. First, the rotation speed of the spindle motor 11 is decreased and the macro seek is re-executed. If it is still determined that step-out or tooth skipping has occurred, the rotation speed of the stepping motor 100 may be decreased. For example, if it is determined that a step-out or tooth skip has occurred after completion of the first macro seek, the macro seek is re-executed by reducing the rotational speed of the spindle motor 11 from 8 × to 6 × (2nd) ), When it is determined that step-out or tooth skipping has occurred after completion of the macro seek, the rotational speed of the stepping motor 100 is decreased by one step. When it is determined that step-out or tooth skipping has occurred after completion of the first macro seek, the rotation speed of the spindle motor 11 is reduced from 8 × to 6 ×, and the macro seek is re-executed and re-executed (second time). If it is determined that step-out or tooth skipping has occurred after completion of the macro seek, the macro seek may be re-executed by further reducing the rotation speed of the spindle motor from 6 × speed to 4 × speed.

  Also, when the seek condition is changed by reducing the rotation speed of the spindle motor 11 and the macro seek is re-executed, the macro seek is normally completed when the macro seek is normally completed without step-out or tooth skipping. When the count value reaches a certain number (for example, 100 times), the seek condition may be returned to the original condition, that is, the original rotation speed. This is because if the macro seek succeeds a certain number of times in succession, there is a possibility that the macro seek can be executed normally even if the original rotational speed is restored. For example, when the macro seek is executed by reducing the rotation speed of the spindle motor 11 from 8 × to 6 ×, and the macro seek can be normally completed 100 times in response to a seek operation command from the host device, the control is performed. The unit 330 returns the rotational speed of the spindle motor 11 from 6 × speed to 8 × speed again, and receives the next macro seek operation command from the host device, and executes macro seek under the condition of 8 × speed. When the macro seek can be normally completed 100 times continuously by reducing the rotation speed of the spindle motor 11 and the stepping motor 100, the rotation speed of the spindle motor 11 is returned to the original rotation speed, or the rotation of the stepping motor 100 is performed. The speed may be returned to the original rotation speed, or both the rotation speed of the spindle motor 11 and the rotation speed of the stepping motor 100 may be returned to the original rotation speed. For example, when the macro seek is normally completed 100 times continuously after the rotation speed of the spindle motor 11 is decreased from 8 × to 6 × and the rotation speed of the stepping motor 100 is decreased from the maximum speed N1 to N2, the spindle For example, only the rotational speed of the motor 11 is returned from 6 × to 8 ×.

  Further, after the seek condition is changed, the macro seek is completed normally for a predetermined number of times (for example, 100 times as described above, but may be arbitrarily set), and then returned to the original rotation speed again. When it is determined that step-out or tooth skipping has occurred, it goes without saying that the rotational speed of the spindle motor 11 or both the rotational speed of the spindle motor 11 and the rotational speed of the stepping motor 100 are reduced. However, when the operation of lowering the rotation speed and returning the rotation speed is repeatedly performed a predetermined number of times, the macro seek cannot be stably performed, and thus the number of repetitions reaches a predetermined number (for example, 5 times). In this case, it is preferable to keep the rotation speed of the spindle motor 11 at a reduced value, or to keep both the rotation speed of the spindle motor 11 and the rotation speed of the stepping motor 100 reduced. For example, the rotation speed of the spindle motor 11 was decreased from 8 × to 6 × and the macro seek was completed normally 100 times, so the rotation speed was returned from 6 × to 8 ×. If the rotation speed is reduced again from 8 times to 6 times, a total of 5 times is repeated, thereafter, the rotation speed of the spindle motor 11 is fixed to 6 times and macro seek is executed.

  The threshold number (for example, 100 times) for returning the rotational speed from the reduced rotational speed state and the repeated threshold number (for example, 5 times) for fixing the rotational speed reduced state are stored in the memory of the control unit 330 in advance. It may be sufficient to make it rewritable.

Second Embodiment
In the above embodiment, it is determined whether or not step-out or tooth skipping has occurred when the macro seek is completed. However, it may be determined that step-out or tooth skipping has occurred before and during the macro seek operation. Note that the configuration of the optical disc apparatus of the present embodiment is the same as the configuration shown in FIG.

  FIG. 4 is a process flowchart for determining whether or not step-out or tooth skipping has occurred before, during, or after completion of the macro seek operation. When a seek operation start command is received from the host device, the tracking servo is turned off (S201), and in the case of the stepping motor 100, it is determined whether or not step-out or tooth skipping has occurred based on whether or not a logical contradiction has occurred. (S202). The stepping motor 100 is managed by a stepper pointer, and represents a rotation amount obtained by integrating seek commands from the innermost position of the stepping motor. The stepper pointer has a microstep as a unit, the innermost peripheral position of the optical pickup 310 is set to 0, and becomes larger toward the outer periphery. For example, 1 microstep is 1/256 rotation by the stepping motor 100, and the optical pickup 310 moves 7.8 μm in 1 microstep. The movable range of the optical pickup 310 is 38000 μm, and the stepper pointer is 4864 when it is located on the outermost periphery. Therefore, the lower limit of the stepper pointer is 0 and the upper limit is 4864. In this way, the stepper pointer does not measure the actual rotation of the lead screw 110 or the amount of movement of the optical pickup 310, but only counts the input to the stepping motor 100. Therefore, when the optical pickup 310 does not move due to step-out or tooth skipping, an error occurs between the actual position of the optical pickup 310 and the stepper pointer. A situation may occur in which the value of the stepper pointer exceeds the upper limit of 4864 despite being located inside the outermost periphery. When such a logical contradiction occurs, it is determined that there is a step-out or tooth skip. If it is determined that there is step-out or tooth skipping (YES in S202), the seek condition is changed, specifically, the macro motor seek is executed by reducing the rotation speed of the spindle motor 11 and the rotation speed of the stepping motor 100 (S212). , S213). At this time, the optical pickup 310 is transferred to the innermost circumference of the optical disc 10 to reset the address of the optical pickup 310, and the processing from S201 is executed.

  When step-out or tooth skipping has not occurred (NO in S202), the stepping motor 100 is driven to start macro seek (S203). After the macro seek is started and the transfer of the optical pickup 310 is started, the control unit 330 determines whether or not step-out or tooth skipping has occurred (S204). In this determination, for example, it is determined whether or not focus down has occurred based on a servo signal from the focus servo 12. Focus down occurs when the level of the focus error signal FE exceeds a predetermined range and the focus servo is disabled. When tooth skipping occurs, the tooth portion 310a provided in the optical pickup 310 and the lead screw. 110 is disengaged and the teeth 310a provided on the optical pickup 310 rides up from the groove of the lead screw 110, and the impact and vibration cause the objective lens of the optical pickup 310 to move steeply in the focus direction. Therefore, it can be considered that the level of the focus error signal FE has increased. Of course, the level of the focus error signal FE may be compared with a threshold value, and if the threshold value is exceeded, it may be determined that a step-out or tooth skip has occurred.

  When it is determined that step-out or tooth skipping has occurred (YES in S204), the control unit 330 interrupts the macro seek (S211). Subsequent processing is the same as in the first embodiment, and the seek condition is changed, specifically, the rotation speed of the spindle motor 11 and the rotation speed of the stepping motor 100 are decreased, and macro seek is executed again (S212, S213). . Even when the macro seek is interrupted, it is preferable to transfer the optical pickup 310 to the innermost periphery, reset the current address to 0, and then execute the macro seek again. After the transfer to the innermost periphery, the macro seek is re-executed after confirming that the address is read and reset to 0.

  On the other hand, if step-out or tooth skipping has not occurred (NO in S204), the macro seek is terminated (S205), and the tracking servo is turned ON again (S206). Then, the current address after completion of the macro seek is read by the decoder 320 (S207) and supplied to the control unit 330. The controller 330 compares the current address at the completion of the macro seek supplied from the decoder 320 with the target address supplied from the host device (S208), and determines whether a step-out or tooth skip has occurred (S208). S209). For example, the amount of deviation between the target address and the current address is calculated, and the calculated amount of deviation and the pitch P of the lead screw 110 are compared in magnitude. Even if it is smaller, if it is equal to or greater than a predetermined threshold value, it is determined that the step-out has occurred. If step-out or tooth skipping has not occurred, that is, step-out or tooth skipping has not occurred during macro seek operation or at the completion of macro seek, normal re-seek processing is executed (S210). On the other hand, when it is determined that step-out or tooth skipping has occurred (YES in S209), the seek condition is changed and the macro seek is executed again as in the first embodiment. That is, the rotational speed (rotational speed) of the spindle motor 11 is reduced (S212), and the drive characteristic (profile) of the stepping motor 100 is changed from the normal profile to the low profile (S213). After changing the rotation speeds of the spindle motor 11 and the stepping motor 100, the optical pickup 310 is transferred to the innermost circumference of the optical disc 10, the address of the optical pickup 310 is reset, and the processing after S201 is executed again to perform macro seek. Try again. In the case of seek re-execution after macro seek, since the current address is known, the rest may be sought again under different conditions. That is, the macro seek after S201 may be executed by the deviation amount.

  As described above, in this embodiment, the presence or absence of step-out or tooth skipping is determined before, during or after completion of the macro seek operation, so that step-out or tooth skipping can be reliably detected.

  Although the case of the stepping motor 100 is shown in the present embodiment, the present invention can be similarly applied to the case of driving with a DC motor.

It is a block diagram of the optical disk apparatus in embodiment. It is a processing flowchart of an embodiment. It is explanatory drawing of the low profile of embodiment. It is a processing flowchart in other embodiments. It is a block diagram of a conventional apparatus. It is transfer mechanism explanatory drawing of a conventional apparatus.

Explanation of symbols

  10 optical disk, 12 focus servo, 100 stepping motor, 310 optical pickup, 320 decoder, 330 control unit, 340 controller, 350 driver.

Claims (6)

A motor,
A transfer mechanism that engages with the motor and transfers the optical pickup in the radial direction of the optical disk by the rotation of the motor;
Control means for lowering the rotational speed of a spindle motor that rotationally drives the optical disk when the stepping out or tooth skip occurs in the transfer mechanism;
I have a,
The control means reduces the rotation speed of the spindle motor to the original rotation speed when the number of times that the step-out or tooth skip does not occur in the transfer mechanism after the rotation speed of the spindle motor is reduced is reached. The rotation speed of the spindle motor is reduced when the number of repetitions in which the rotation speed is reduced again after the rotation speed of the spindle motor is restored to the original rotation speed reaches a second predetermined number of times. An optical disk device characterized by maintaining the state in a closed state . A motor,
A transfer mechanism that engages with the motor and transfers the optical pickup in the radial direction of the optical disk by the rotation of the motor;
Control means for lowering the rotational speed of a spindle motor that rotationally drives the motor and the optical disc when a step-out or tooth skip occurs in the transfer mechanism;
Have
The control means reduces the rotation speed of the spindle motor and reduces the rotation speed of the motor, and when the number of times that the step-out or tooth skip does not occur in the transfer mechanism reaches a predetermined number. And at least one of the rotational speed of the motor and the rotational speed of the motor is restored to the original rotational speed, and the spindle motor or the rotational speed of the motor is restored to the original rotational speed, and then the spindle motor again. The rotation speed of the spindle motor or the rotation speed of the motor is maintained in a reduced state when the number of repetitions of decreasing the rotation speed of the motor or the rotation speed of the motor reaches a second predetermined number of times. Optical disk device. The apparatus according to claim 1,
The control means compares the shift amount between the address after the transfer by the transfer mechanism and the target address with the pitch of the transfer mechanism, and when the shift amount is equal to or greater than the pitch, the transfer mechanism generates tooth skipping. An optical disc apparatus characterized by determining that The apparatus according to claim 1,
The control means determines that tooth skipping has occurred in the transfer mechanism when focus control by the focus servo means is interrupted in response to a servo signal from a focus servo means that performs focus control of the optical pickup. Optical disk device to perform. The apparatus according to claim 1,
The optical disk apparatus according to claim 1, wherein the control means determines that tooth skipping has occurred in the transfer mechanism when a level of a focus error signal generated from a reproduction signal of the optical pickup exceeds a predetermined threshold value . The apparatus according to claim 1,
The optical disc apparatus , wherein the control means determines that a step-out has occurred in the transfer mechanism when an amount of deviation between an address after the transfer by the transfer mechanism and a target address is a predetermined threshold value or more .

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