JP2006221808A - Feed controller for optical pickup - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide operating performance that is not changed at all the time even when an operating temperature environment is different or there is a response delay at the detection part of an error signal. <P>SOLUTION: A feed controller comprises an optical pickup 4 for recording or reproducing information on a disk 1, a traverse motor 5 for moving the optical pickup 4 via a power transmitting mechanism 6, and a controller 10 for controlling the driving force of this traverse motor 5. In this case, after the time point when a lens shift quantity detected by a lens shift detecting means 8 exceeds a prescribed threshold value, a driving voltage corresponding to the lens shift quantity is calculated by a traverse motor drive output operating means 103 and applied to the traverse motor 5. After this driving voltage is outputted to the traverse motor 5 just for the specified time set by a motor voltage application time setting means 105, the supply of the driving voltage is controlled to be stopped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a feed control device for an optical pickup used in an optical disk device, and in particular, an optical that can prevent the occurrence of malfunction even when the operating temperature environment is different or there is a response delay in an error signal detection unit. The present invention relates to a pickup feed control device.

  This type of conventional optical pickup feed control device will be described with reference to FIGS.

  In FIG. 10, the disk 1 is rotated by a spindle motor 2, and the spindle motor 2 is controlled by a spindle motor driver 3 so that the linear velocity on the optical head is constant. The optical pickup 4 optically reads information recorded on the disk 1 and converts it into an electrical signal, or optically writes information on the disk 1. The optical pickup 4 collects a laser beam on the disk 1. An objective lens 4a for reading data composed of pits on the disk 1, a dense actuator 4b for minutely moving the objective lens 4a in the vertical direction (focus direction) and the radial direction of the disk 1 (tracking direction), A carriage 4c on which the objective lens 4a and the dense actuator 4b are mounted is provided.

  The feed mechanism that moves the optical pickup 4 in the radial direction (tracking direction) of the disk 1 includes a traverse motor 5 and a power transmission mechanism 6 that includes a feed screw that transmits the driving force of the traverse motor 5 to the carriage 4c. Is done.

  The controller 7 controls the fine actuator 4b and the traverse motor 5, has a spindle motor driver 3, and includes a fine actuator drive output means 71 and a constant voltage pulse generation means 72. The voltage pulse generating means 72 is connected to a lens shift detecting means 8 for detecting an amount of deviation of the objective lens 4a from the carriage center (hereinafter referred to as a lens shift amount). The fine actuator drive output means 71 sends a drive output signal to the fine actuator 4b in accordance with the lens shift amount detected by the lens shift detection means 8, and performs fine feed control of the fine actuator 4b in the tracking direction. The constant voltage pulse generating means 73 applies a constant voltage pulse generated according to the lens shift amount detected by the lens shift detecting means 8 to the traverse motor 5 to control the movement of the carriage 4c.

  Next, the operation of the optical pickup feed control device configured as described above will be described. When information recorded on the disk 1 is reproduced, an operation (hereinafter referred to as optical axis correction feed) is performed in which the carriage 4c is sent in the disk radial direction (hereinafter referred to as tracking direction). Hereinafter, this operation will be described.

  During the reproducing operation, the objective lens 4a of the optical pickup 4 traces the track of the rotating disk 1 and reads data while moving finely toward the outer periphery in the tracking direction by the dense actuator 4b. In this case, the dense actuator 4b is configured to be able to move precisely, but its movable range is narrow, and therefore when the objective lens 4a is displaced from the center of the carriage 4c by a predetermined distance or more (hereinafter, a lens shift occurs). It is necessary to move the carriage 4c and return the objective lens 4a to the vicinity of the center position of the carriage 4c again. In order to move the carriage 4c, a constant voltage pulse that exceeds the friction load of the power transmission mechanism 6 is output from the constant voltage pulse generating means 72, and the constant voltage pulse is applied to the traverse motor 5 and driven to drive the power. This is done by moving the carriage 4c in the tracking direction via the transmission mechanism 6.

  For this reason, the controller 7 normally controls the dense actuator 4b to follow the track of the disk 1 (tracking control) and drives the traverse motor 5 as necessary to control the objective lens 4a near the center position of the carriage 4c ( Traverse control) is performed simultaneously.

  Hereinafter, this operation will be described in detail with reference to FIGS. FIG. 11 is a flowchart showing the operation procedure of the conventional optical axis correction feed, and FIG. 12 is an explanatory diagram of the operation of the conventional optical axis correction feed.

  When a command for reproducing operation is received, first, the lens shift detecting means 8 detects the lens shift amount (step S111), and determines whether or not the carriage 4c needs to be moved. That is, it is determined whether or not the lens shift amount is greater than or equal to a threshold value (step S112). Here, when the shift amount is less than the threshold value and within the movable range of the fine actuator 4b, a drive output signal is output from the fine actuator drive output means 71 to the fine actuator 4b, and the fine actuator 4b is finely fed in the tracking direction. (Step S113). Then, by executing the processing of step S111 to step S113, the lens shift amount gradually increases, and when it exceeds the threshold value, the process shifts to the optical axis correction feed processing (step S114).

  In the optical axis correction feed process, as shown in FIG. 12A, when the lens shift amount becomes equal to or larger than the threshold value, a constant voltage pulse (motor drive pulse) is sent from the constant voltage pulse generating means 72 as shown in FIG. ) And applying this constant voltage pulse to the traverse motor 5, thereby moving the carriage 4c in the direction in which the lens shift amount is canceled (usually the outer circumferential direction of the disk) (step S115). Then, it is determined whether or not the lens shift amount is equal to or larger than the threshold value due to the movement of the carriage 4c (step S116). If the lens shift amount is equal to or larger than the threshold value, the process proceeds to step S65 and the processes of steps S115 to S116 are executed. To do. When the lens shift amount decreases and becomes less than the threshold value again, the supply of the drive voltage to the traverse motor 5 is stopped (step S117), and the first optical axis correction feed process ends (step S118). ), The process returns to step S111 again, and only the lens movement is controlled by the dense actuator 4b. Thus, the above-described operation is repeated during the reproduction operation.

In this way, an optical axis correction feed operation can be performed even with a conventional optical pickup feed control device.
JP-A-6-119650

  In general, the dense actuator 4b has good movement accuracy and is less affected by the operating environment temperature. However, the driving force transmission mechanism 6 that performs the feeding operation of the carriage 4c is easily influenced by the operating environment temperature. That is, since the grease hardens at low temperatures and the frictional load of the power transmission mechanism 4c increases, a larger driving force is required than at normal temperatures. On the other hand, the braking force due to the viscosity of the grease decreases at high temperatures. Increases the amount of movement.

  Therefore, in the conventional optical pickup feed control device as described above, when applied to a vehicle-mounted device whose operating environment temperature is greatly different, the friction load of the power transmission mechanism fluctuates greatly, and the pulse height of the constant voltage pulse is increased. The relative relationship of the friction load changes, the carriage stops moving due to the increase in load due to grease hardening at low temperature, and if the drive voltage is set high to prevent this, the carriage feed amount becomes excessive at high temperatures. There was a problem that operation became unstable.

  Further, in the conventional optical pickup feed control device, a constant voltage pulse is applied to the traverse motor to drive the traverse motor according to the detected magnitude of the lens shift amount and the threshold value, so whether to supply the motor drive voltage is determined. Due to the presence of the response delay time of the lens shift amount detection unit, the detected value of the lens shift amount does not fall below the threshold value even though the carriage has actually moved. There is a problem that the operation becomes unstable due to excessive carriage feed amount.

  Furthermore, the conventional optical pickup feed control device is driven by applying a constant voltage pulse to the traverse motor depending on the detected lens shift amount and the threshold value, so that a disc with an off-center eccentricity is reproduced. Further, there is a problem that an eccentric component is superimposed on the lens shift detection signal, and a motor drive voltage is generated as a feed voltage in both forward and reverse directions, and the carriage feed operation becomes unstable.

  The present invention solves such a conventional problem, and a first object of the present invention is to provide a feed control device for an optical pickup that can always obtain an operating performance that is not changed even if the operating temperature environment is different. It is to provide.

  A second object of the present invention is to provide an optical pickup feed control device that can always obtain the same operation performance even when a delay time exists in the lens shift amount detection unit.

  A third object of the present invention is to provide a feed control device for an optical pickup which can always obtain the same operation performance even when a disc having a non-standard eccentricity is reproduced.

  In order to achieve the first object, in the optical pickup feed control apparatus according to the present invention, the lens shift detecting means for detecting the lens shift amount of the lens system, and the lens shift amount detected by the lens shift detecting means are predetermined. And a traverse motor drive output calculating means for applying a drive voltage corresponding to the lens shift amount to the traverse motor from the time when the threshold value is exceeded, and a control for stopping the supply of the drive voltage after outputting the drive voltage for a specified time Means.

  According to the present invention, it is possible to obtain an operation performance that does not change even when the operating temperature environment is different.

  In order to achieve the second object, in the optical pickup feed control apparatus according to the present invention, the lens shift detecting means for detecting the lens shift amount of the lens system, and the lens shift amount detected by the lens shift detecting means are predetermined. A traverse motor drive output calculating means for applying a driving voltage corresponding to the lens shift amount to the traverse motor from the time when the threshold value is exceeded, and a first driving voltage output from the traverse motor drive output calculating means for a specified time. Control means and second control means for stopping and controlling the output of the drive voltage from the traverse motor drive output calculating means for a specified time from the time when the specified drive voltage is output.

  According to the present invention, even if there is a delay time in the lens shift amount detection unit, it is possible to always obtain the same operating performance.

  In order to achieve the third object, in the optical pickup feed control apparatus of the present invention, the lens shift detection means for detecting the lens shift amount of the lens system, and the lens shift amount detected by the lens shift detection means are predetermined. A traverse motor drive output calculating means for applying a driving voltage corresponding to the lens shift amount to the traverse motor from the time when the threshold value is exceeded, and a first driving voltage output from the traverse motor drive output calculating means for a specified time. Control of the drive voltage output from the traverse motor drive output calculation means from the time when the specified time drive voltage is output based on the drive voltage stop time calculated from the control means and the relative position of the optical pickup to the disk And a second control means.

  According to the present invention, even when a disc having a non-standard eccentricity is reproduced, it is possible to always obtain the same operating performance.

  According to the present invention, as is clear from the above-described embodiment, it is possible to prevent an excessive supply of drive voltage caused by a lens shift detection delay, and it is possible to prevent the occurrence of excessive feed and stabilize feed.

  The present invention relates to an optical pickup having a lens system that records or reproduces information by condensing light on a disk, and controls the relative position between the optical pickup and the disk while moving the optical pickup in the disk radial direction. In a feed control device for an optical pickup having a traverse motor to be moved, a lens shift detection unit for detecting a lens shift amount of the lens system, and a lens shift amount detected by the lens shift detection unit exceeds a predetermined threshold value. A traverse motor drive output calculating means for applying a driving voltage corresponding to the lens shift amount from the time point to the traverse motor; a first control means for outputting a driving voltage from the traverse motor drive output calculating means for a specified time; The traverser for a specified time from the time when the driving voltage is output In which and a second control means for stopping controlling the output of the driving voltage from the motor drive output calculating means.

  In the present invention, the first control means starts counting at the same time as the start of the optical axis correction feed control and counts the elapsed time, and the traverse motor drive output computing means changes the traverse motor during the optical axis correction feed control. The motor voltage application time setting means for setting the application time of the supplied voltage, the motor voltage application time set by the motor voltage application time setting means and the elapsed time counted by the timer counter are compared, and the elapsed time And a comparison means for sending a stop signal to the traverse motor drive output calculation means when the motor voltage application time is longer than or equal to the motor voltage application time. Motor supply voltage stop time setting means for setting a voltage supply stop time to the traverse motor, and the traverse motor drive Only a force calculation means and the motor supply voltage time set by the stop time setting means are those composed of a stop control means for stopping.

  Therefore, in the optical axis correction feeding operation of the optical disc apparatus, the lens shift amount is detected, and the driving voltage corresponding to the lens shift amount is applied to the traverse motor from the time when the lens shift amount exceeds a predetermined threshold value. By supplying only the specified time t1, and then controlling the motor voltage to stop only for the specified time t2, appropriate driving force is supplied even if the frictional load fluctuates due to temperature change, load variation, etc., and lens shift at the same time It has the effect of canceling the influence of the delay in the detection response time, preventing the occurrence of overfeeding, and stabilizing the feed.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an optical pickup feed control apparatus according to Embodiment 1 of the present invention, FIG. 2 is a flowchart showing an optical axis correction feed operation according to Embodiment 1 of the present invention, and FIG. FIG. 6 is a waveform diagram for explaining operations during optical axis correction feeding in the first embodiment.

  In FIG. 1, 1 is a disk, and 2 is a spindle motor that rotates the disk 1. Reference numeral 4 denotes an optical pickup that optically reads information recorded on the disk 1 and converts it into an electrical signal, or optically writes information on the disk 1. The optical pickup 4 is a laser on the disk 1. The objective lens 4a for reading the data composed of the pits on the disk 1 by focusing the light and the objective lens 4a for minute movement in the vertical direction (focus direction) and the radial direction of the disk 1 (tracking direction). And a carriage 4c on which the objective lens 4a and the dense actuator 4b are mounted. Reference numeral 8 denotes lens shift detection means for detecting a shift amount of the objective lens 4a from the carriage center (hereinafter referred to as a lens shift amount).

  Reference numeral 10 denotes a controller for controlling the dense actuator 4b and the traverse motor 5. The controller 10 controls the spindle motor 2 by the spindle motor driver 3 so that the linear velocity on the optical head is constant, A fine actuator drive output means 102 that sends a drive output signal to the fine actuator 4b in accordance with the lens shift amount detected by the lens shift detection means 8 and finely controls the fine actuator 4b in the tracking direction, and the lens shift detection means 8 A traverse motor drive output calculating means 103 for calculating a traverse motor drive output corresponding to the lens shift amount detected in step 1, a timer counter 104 for starting counting simultaneously with the start of the optical axis correction feed control and counting the elapsed time tc, Motor voltage application time setting means 105 for setting the application time t1 of the voltage supplied from the traverse motor drive output calculation means 103 to the traverse motor 5 during the optical axis correction feed control, and the motor set by the motor voltage application time setting means 105 Comparing means 106 that compares the voltage application time t1 with the elapsed time tc counted by the timer counter 104 and sends a stop signal when tc> t1 is provided. The traverse motor drive output calculation means 103 starts the calculation of the motor drive output voltage based on the signal at the start of counting by the timer counter 104 and outputs the motor voltage. The traverse motor drive output calculation means 103 outputs the motor voltage based on the output signal from the comparison means 106. The calculation is stopped and the voltage supply to the traverse motor 5 is stopped.

  Next, the operation of the optical pickup feed control apparatus according to Embodiment 1 of the present invention configured as described above will be described with reference to FIGS.

  When a command for reproducing operation is received, first, the lens shift detection means 8 detects the lens shift amount (step S21), and determines whether or not the carriage 4c needs to be moved. That is, it is determined whether the lens shift amount is equal to or greater than a threshold value (step S22). Here, when the shift amount is less than the threshold value and within the movable range of the fine actuator 4b, a drive output signal is output from the fine actuator drive output means 102 to the fine actuator 4b, and the fine actuator 4b is finely fed in the tracking direction. (Step S23). Then, by executing the processing of step S21 to step S23, the lens shift amount gradually increases, and when this lens shift amount becomes equal to or greater than the threshold value as shown in FIG. Step S24).

  When the optical axis correction feed processing starts, the timer counter 104 is first reset and then started (step S25), and then the traverse motor drive output calculation means 103 responds to the lens shift amount detected by the lens shift detection means 8. The drive output voltage is calculated (step S26), and this voltage is applied to the traverse motor 5 (step S27). Thereby, the carriage 4c is moved in the direction in which the lens shift amount is canceled.

  Here, a tracking error signal is normally used as the lens shift amount, and a low-frequency component of this signal is extracted by a filter and amplified to generate a traverse motor drive output. At this time, the frequency band of the traverse servo is very low, and the relationship between the lens shift amount and the traverse motor drive output is approximately proportional.

  The elapsed time tc of the voltage supplied from the traverse motor drive output calculation means 103 to the traverse motor 5 is counted by the timer counter 104. The elapsed time tc is compared with the motor voltage application time t1 set by the motor voltage application time setting means 105 by the comparison means 106 to determine whether the motor voltage application time t1 is tc <t1 (step S28). When tc <t1, the process returns to step S26, and while the elapsed time tc is smaller than the motor voltage application time t1 set by the motor voltage application time setting means 105, the processes of steps S26 to S28 are repeatedly executed. The motor voltage output from the traverse motor drive output calculation unit 103 according to the lens shift amount is continuously supplied to the traverse motor 5.

  If the determination result by the comparison unit 106 is not tc <t1, that is, if the elapsed time tc exceeds the motor voltage application time t1, the traverse motor drive output calculation unit 103 is stopped by a signal output from the comparison unit 106. Then, the supply of the drive output voltage to the traverse motor 5 is stopped (step S29), and the feed of the carriage 4c is stopped. After the carriage 4c is stopped, the lens shift amount is detected again by the lens shift detection means 8, and it is determined again by the controller 10 whether the lens shift amount is equal to or larger than the threshold value (step S30). If the lens shift amount is greater than or equal to the threshold value, the process returns to step S25, and the timer counter 104 is reset and started again until the lens shift amount falls below the threshold value. repeat. As a result, the voltage having the waveform shown in FIG. 3B is intermittently supplied from the traverse motor drive output calculation means 103 to the traverse motor 5.

  At this time, since the lens 4b is always operated by the tracking servo, the lens shift amount becomes a larger value than the previous time. For this reason, the supply start voltage value is also increased, resulting in a drive voltage waveform as shown in FIG. Further, when the friction load and the supply start voltage match, the carriage 4c moves. When the lens shift amount becomes equal to or smaller than the threshold value due to the movement of the carriage 4c, the optical axis correction feeding operation is ended (step S31).

  As described above, according to the first embodiment of the present invention, the variation in the friction load due to the difference in the temperature environment and the variation in the load is absorbed by setting the driving voltage of the traverse motor to a value adapted to the friction load. It is possible to prevent the occurrence of an excessive amount of movement and stabilize the feed.

(Embodiment 2)
FIG. 4 is a block diagram showing the configuration of the optical pickup feed control apparatus according to the second embodiment of the present invention, FIG. 5 is a flowchart showing the optical axis correction feed operation according to the second embodiment of the present invention, and FIG. FIG. 11 is a waveform diagram for explaining operations during optical axis correction feeding in the second embodiment.

  In FIG. 4, the same components as those in FIG. 1 are denoted by the same reference numerals, description of the components is omitted, and portions different from those in FIG. The second embodiment is different from FIG. 1 in the internal configuration of the controller 10, and as in the case shown in FIG. 1, the spindle motor driver 101, the fine actuator drive output means 102, the traverse motor drive output calculation means 103, the timer In addition to the counter 104, the motor voltage application time setting means 105, and the comparison means 106, the motor supply voltage stop time setting means 107 and the traverse motor drive output calculation means 103 are newly set by the motor supply voltage stop time setting means 107. The stop control means 108 for stopping only for the time is added.

  The motor supply voltage stop time setting means 107 sets the voltage supply stop time t2 to the traverse motor 5 from the time when the motor voltage application time t1 has passed. The motor voltage supply stop time t2 is the lens shift detection means. 8 is set to a value that is sufficiently larger than the delay time existing inside 8. The stop control means 108 calculates the stop time of the traverse motor drive output calculating means 103 based on the elapsed time tc counted by the timer counter 104 and the motor voltage supply stop time t2, and based on the calculation result, the traverse motor The drive output calculation means 103 is controlled to stop during t2.

  Next, the operation of the optical pickup feed control apparatus according to Embodiment 2 of the present invention configured as described above will be described with reference to FIGS.

  When a command for reproducing operation is received, first, a lens shift amount is detected by the lens shift detecting means 8 (step S51), and it is determined whether or not the carriage 4c needs to be moved. That is, it is determined whether or not the lens shift amount is greater than or equal to a threshold value (step S52). Here, when the shift amount is less than the threshold value and within the movable range of the fine actuator 4b, a drive output signal is output from the fine actuator drive output means 102 to the fine actuator 4b, and the fine actuator 4b is finely fed in the tracking direction. (Step S53). Then, by executing the processing of step S51 to step S53, the lens shift amount gradually increases, and when this lens shift amount becomes equal to or larger than the threshold value as shown in FIG. Step S54).

  When the optical axis correction feed process starts, the timer counter 104 is first reset and then started (step S55), and then the traverse motor drive output calculation unit 103 responds to the lens shift amount detected by the lens shift detection unit 8. The drive output voltage is calculated (step S56), and this voltage is applied to the traverse motor 5 (step S57). Thereby, the carriage 4c is moved in the direction in which the lens shift amount is canceled.

  Here, a tracking error signal is normally used as the lens shift amount, and a low-frequency component of this signal is extracted by a filter and amplified to generate a traverse motor drive output. At this time, the frequency band of the traverse servo is very low, and the relationship between the lens shift amount and the traverse motor drive output is approximately proportional.

  The elapsed time tc of the voltage supplied from the traverse motor drive output calculation means 103 to the traverse motor 5 is counted by the timer counter 104. The elapsed time tc is compared with the motor voltage application time t1 set by the motor voltage application time setting means 105 by the comparison means 106 to determine whether the motor voltage application time t1 is tc <t1 (step S58). When tc <t1, the process returns to step S56, and while the elapsed time tc is smaller than the motor voltage application time t1 set by the motor voltage application time setting means 105, the processes of steps S56 to S58 are repeatedly executed. The motor voltage output from the traverse motor drive output calculation unit 103 according to the lens shift amount is continuously supplied to the traverse motor 5.

  If the determination result by the comparison unit 106 is not tc <t1, that is, if the elapsed time tc exceeds the motor voltage application time t1, the traverse motor drive output calculation unit 103 is stopped by a signal output from the comparison unit 106. Then, the supply of the drive output voltage to the traverse motor 5 is stopped (step S59), and the feed of the carriage 4c is stopped.

  In this stop state, the stop time calculating means 108 calculates the stop time based on the elapsed time tc counted by the timer counter 104 and the motor voltage supply stop time t2 set by the motor supply voltage stop time setting means 107, It is determined whether the motor voltage supply stop time t2 has been reached (step S60). That is, it is determined whether or not the elapsed time tc from the start of the timer counter 104 in step S55 is within t1 + t2. If it is determined that the elapsed time tc has not reached the time t1 + t2, the process returns to step S59, and the processes in steps S59 and S60 are repeatedly executed until the elapsed time tc becomes equal to or longer than the time t1 + t2. Then, after stopping for the time t2, the lens shift amount is detected again by the lens shift detecting means 8, and it is determined again by the controller 10 whether the lens shift amount is equal to or larger than the threshold value (step S61). If the lens shift amount is greater than or equal to the threshold value, the process returns to step S55, and the timer counter 104 is reset and started again until the lens shift amount falls below the threshold value. repeat. As a result, the voltage having the waveform shown in FIG. 6B is intermittently supplied from the traverse motor drive output calculation means 103 to the traverse motor 5.

  At this time, since the lens 4b is always operated by the tracking servo, the lens shift amount becomes a larger value than the previous time. For this reason, the supply start voltage value is also increased, resulting in a drive voltage waveform as shown in FIG. Further, when the friction load and the supply start voltage match, the carriage 4c moves. When the lens shift amount becomes equal to or smaller than the threshold value due to the movement of the carriage 4c, the optical axis correction feeding operation is ended (step S62).

  As described above, according to the second embodiment of the present invention, the variation in the friction load due to the difference in the temperature environment and the variation in the load can be absorbed by setting the driving voltage of the traverse motor to a value adapted to the friction load, and By stopping the supply of drive power during the response delay time of the lens shift amount detection unit, it is possible to prevent the occurrence of overfeeding and stabilize feed.

(Embodiment 3)
FIG. 7 is a block diagram showing the configuration of the optical pickup feed control apparatus according to the third embodiment of the present invention, FIG. 8 is a flowchart showing the optical axis correction feed operation according to the third embodiment of the present invention, and FIG. FIG. 11 is a waveform diagram for explaining operations during optical axis correction feeding in the third embodiment.

  In FIG. 7, the same components as those in FIG. 1 are denoted by the same reference numerals, description of the components is omitted, and portions different from those in FIG. The second embodiment is different from FIG. 1 in the internal configuration of the controller 10, and as in the case shown in FIG. 1, the spindle motor driver 101, the fine actuator drive output means 102, the traverse motor drive output calculation means 103, the timer In addition to the counter 104, the motor voltage application time setting means 105, and the comparison means 106, the motor voltage supply stop time calculating means 109 for calculating the motor voltage stop time tv from the relative position of the optical pickup 4 with respect to the disk 1, and the timer counter 104 The stop control means 110 for stopping and controlling the traverse motor drive output calculation means 103 for the time tv based on the elapsed time tc counted in the above and the calculated time tv is newly added.

  Next, the operation of the third embodiment configured as described above will be described with reference to FIGS.

  First, prior to explaining the operation of the third embodiment, referring to FIG. 9A, the motor voltage and the carriage displacement with respect to the lens shift amount when a disc having a non-standard eccentric amount in the conventional example is reproduced. explain.

  The lens shift amount with respect to a disc having a non-standard eccentricity changes as shown in FIG. For this reason, when a constant voltage pulse drive is performed on the traverse motor according to the relationship between the lens shift amount detected by the lens shift detection means and the threshold value, both forward and reverse directions as shown in FIG. As a result, a feed motor voltage is generated, and as a result, the displacement of the optical pickup carriage changes in both the inner and outer circumferences of the disk as shown in FIG. .

  Therefore, in the third embodiment of the present invention, the lens shift detection is always performed in the same phase by synchronizing the time interval for comparing the lens shift amount with the threshold value with the eccentric frequency, thereby reducing the influence of the eccentric component. This prevents the generation of a motor voltage for receiving and feeding the disc in both the inner and outer circumferential directions. Hereinafter, the principle of this method will be described.

  The lens shift amount when there is non-standard eccentricity on the disc is the DC component element whose offset value gradually increases with time and the AC component due to the eccentric frequency at the position where the lens is currently reading information. It is the sum of elements.

  Since information is recorded on an optical disk such as a CD at a constant linear velocity, the rotational speed of the disk changes due to the relative displacement of the pickup lens with respect to the disk (from 3.3 (outermost circumference) to 8.9 (maximum outer circumference) to 1-times speed rotation). Inner circumference) Hz). Here, the frequency of the eccentric component of the disk is calculated by the following equation.

fh = VL / (2.pi.r) (1)
fh: disk eccentric frequency (Hz)
VL: Disk linear velocity (m / s)
r: Disc relative position (m)
The relative position r of the disk is calculated by the following equation (1).

レンズシフト量をしきい値と比較する時間間隔（以下モータ電圧供給停止時間）を偏心周波数に同期するように設定した場合、ｔｖは次式にて求められる。

When the time interval (hereinafter referred to as motor voltage supply stop time) for comparing the lens shift amount with the threshold value is set so as to be synchronized with the eccentric frequency, tv is obtained by the following equation.

tv = 1 / fh (3)
tv: Motor voltage supply stop time (s)
fh: disk eccentric frequency (Hz)
The motor voltage supply stop time calculating means 109 performs the calculation as described above to calculate the lens shift amount detection time interval tv.

  Next, the actual operation will be described with reference to FIG.

  When a command for reproducing operation is received, first, the lens shift detection means 8 detects the lens shift amount (step S81), and determines whether or not the carriage 4c needs to be moved. That is, it is determined whether the lens shift amount is equal to or greater than a threshold value (step S82). Here, when the shift amount is less than the threshold value and within the movable range of the fine actuator 4b, a drive output signal is output from the fine actuator drive output means 102 to the fine actuator 4b, and the fine actuator 4b is finely fed in the tracking direction. (Step S83). Then, by executing the processing of step S51 to step S53, the lens shift amount gradually increases, and when this lens shift amount becomes equal to or larger than the threshold value as shown in FIG. Step S84).

  When the optical axis correction feed process starts, the timer counter 104 is first reset and then started (step S85), and then the traverse motor drive output calculation unit 103 responds to the lens shift amount detected by the lens shift detection unit 8. The drive output voltage is calculated (step S86), and this voltage is applied to the traverse motor 5 (step S87). Thereby, the carriage 4c is moved in the direction in which the lens shift amount is canceled.

  Here, a tracking error signal is normally used as the lens shift amount, and a low-frequency component of this signal is extracted by a filter and amplified to generate a traverse motor drive output. At this time, the frequency band of the traverse servo is very low, and the relationship between the lens shift amount and the traverse motor drive output is approximately proportional.

  The elapsed time tc of the voltage supplied from the traverse motor drive output calculation means 103 to the traverse motor 5 is counted by the timer counter 104. The elapsed time tc is compared with the motor voltage application time t1 set by the motor voltage application time setting means 105 by the comparison means 106 to determine whether the motor voltage application time t1 is tc <t1 (step S88). When tc <t1, the process returns to step S86, and while the elapsed time tc is smaller than the motor voltage application time t1 set by the motor voltage application time setting means 105, the processes of steps S86 to S88 are repeatedly executed. The motor voltage output from the traverse motor drive output calculation unit 103 according to the lens shift amount is continuously supplied to the traverse motor 5.

  If the determination result by the comparison means 106 is not tc <t1, that is, if the elapsed time tc exceeds the motor voltage application time t1, the traverse motor drive output calculation means 103 is stopped by a signal output from the comparison means 106. Then, the supply of the drive output voltage to the traverse motor 5 is stopped (step S89), and the feed of the carriage 4c is stopped. In this stop state, the motor voltage stop time tv is calculated by the motor voltage supply stop time calculating means 109 from the current address, that is, the relative position of the optical pickup 4 with respect to the disk 1 (step S90), and the traverse motor drive is calculated for the calculated time tv. Stop control is performed so that the drive output of the output calculation means 103 is not supplied to the traverse motor 5.

  Next, it is determined whether the motor voltage supply stop time tv has been reached (step S91). That is, it is determined whether the elapsed time tc from the start of the timer counter 104 in step S85 is within t1 + tv or more. If it is determined that the elapsed time tc has not reached the time t1 + tv, the process returns to step S89, and the processes in steps S89 to S91 are repeatedly executed until the elapsed time tc becomes equal to or longer than the time t1 + tv. Then, after stopping for the time tv, the lens shift amount is detected again by the lens shift detecting means 8, and it is again determined by the controller 10 whether the lens shift amount is equal to or larger than the threshold value (step S92). If the lens shift amount is greater than or equal to the threshold value, the process returns to step S85, the timer counter 104 is reset again and started, and a series of processing from step S85 onward is continued until the lens shift amount falls below the threshold value. repeat. As a result, the traverse motor drive output calculation means 103 intermittently supplies the voltage having the waveform shown in FIG. 9B to the traverse motor 5, and the displacement of the optical pickup carriage is as shown in FIG. 9B. In this way, the waveform becomes a stepped waveform that does not change in both the inner and outer circumferences of the disk.

  At this time, since the lens 4b is always operated by the tracking servo, the lens shift amount becomes a larger value than the previous time. For this reason, the supply start voltage value is also increased, resulting in a drive voltage waveform as shown in FIG. Further, when the friction load and the supply start voltage match, the carriage 4c moves. When the lens shift amount becomes equal to or smaller than the threshold value due to the movement of the carriage 4c, the optical axis correction feeding operation is ended (step S93).

  As described above, according to the third embodiment of the present invention, the interval for detecting the lens shift amount is set to a timing synchronized with the eccentric frequency, thereby preventing generation of unnecessary motor voltage, due to temperature variation, load variation, and the like. Appropriate driving power is supplied even if the friction load fluctuates, and at the same time, the influence of the delay in response time for detecting the lens shift amount can be canceled, and the eccentric component is greatly superimposed on the lens shift amount detection signal when using a disc with large eccentricity. Even in the case of the failure, the influence can be canceled, the occurrence of the hunting operation can be prevented, and the feed can be stabilized.

  The optical pickup feed control device according to the present invention can prevent excessive supply of drive voltage caused by detection delay of lens shift, and can prevent the occurrence of overfeed and stabilize feed. It is useful as a feed control device for an optical pickup used in the above.

1 is a block diagram showing the configuration of an optical pickup feed control device in Embodiment 1 of the present invention. The flowchart which shows the operation | movement of the optical axis correction | amendment feed in Embodiment 1 of this invention. Waveform diagram for explaining operation at the time of optical axis correction feeding in Embodiment 1 of the present invention The block diagram which shows the structure of the optical pick-up feed control apparatus in Embodiment 2 of this invention. Flowchart showing the operation of optical axis correction feeding in Embodiment 2 of the present invention. Waveform diagram for explaining operation at the time of optical axis correction feeding in Embodiment 2 of the invention The block diagram which shows the structure of the optical pick-up feed control apparatus in Embodiment 3 of this invention. Flowchart showing the operation of optical axis correction feeding in Embodiment 3 of the present invention. Waveform diagram for explaining operation at the time of optical axis correction feeding in Embodiment 3 of the present invention Block diagram showing the configuration of a conventional optical pickup feed control device Flow chart showing conventional optical axis correction feed operation Waveform diagram for explaining operations during conventional optical axis correction feed

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Disc 2 Spindle motor 4 Optical pickup 4a Lens 4b Dense actuator 4c Carriage 5 Traverse motor 6 Power transmission mechanism 8 Lens shift detection means 10 Controller 101 Spindle motor driver 102 Dense actuator drive output means 103 Traverse motor drive output calculation means 104 Timer counter 105 Motor voltage application time setting means 106 Comparison means 107 Motor supply voltage stop time setting means 108 Stop control means 109 Motor voltage supply stop time calculation means 110 Stop control means

Claims (2)

An optical pickup having a lens system for recording or reproducing information by condensing light on the disc, and a traverse motor for moving the optical pickup in the disc radial direction while controlling the relative position of the optical pickup and the disc A lens shift detecting means for detecting a lens shift amount of the lens system, and a lens shift from a time when the lens shift amount detected by the lens shift detecting means exceeds a predetermined threshold value. A traverse motor drive output calculating means for applying a drive voltage according to the amount to the traverse motor; a first control means for outputting a drive voltage from the traverse motor drive output calculating means for a specified time; and a relative of the optical pickup to the disk Drive voltage stop calculated from position Feed control of an optical pickup, comprising: second control means for stopping and controlling output of the drive voltage from the traverse motor drive output calculation means from the time when the drive voltage is output for a specified time based on the interval apparatus. The first control means includes a timer counter that starts counting simultaneously with the start of the optical axis correction feed control and counts the elapsed time, and a voltage supplied from the traverse motor drive output calculation means to the traverse motor during the optical axis correction feed control. The motor voltage application time setting means for setting the application time of the motor, the motor voltage application time set by the motor voltage application time setting means and the elapsed time counted by the timer counter are compared, and the elapsed time is applied to the motor voltage. Comparing means for sending a stop signal to the traverse motor drive output calculating means when the time is over, the second control means is a motor for calculating the motor voltage stop time tv from the relative position of the optical pickup to the disk. Voltage supply stop time calculation means, elapsed time counted by a timer counter and the calculated time v The optical pickup feed control apparatus according to claim 1 comprised the traverse motor drive output calculation means for a time tv and a stop control means for stopping control based on.

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