JPH08147906A - Disk reproducing device - Google Patents

Abstract

PURPOSE: To secure the speed at the high speed feed time of a slide part and also to perform a stable slow speed feed by executing changing control for supplying a pulse-like voltage of which peak voltage value is lower than a DC voltage supplied at the high speed feed time to a slide feed motor at the low speed feed time. CONSTITUTION: The device is provided with a slow speed feed time changeover control device for changing and controlling so that a pulse-like voltage of which peak voltage value is lower than the DC voltage supplied at the high speed feed time is supplied to the slide feed motor at the slow speed feed time of the slide part 2. Thus, the feed speed at the high speed feed time can be secured, and also the stable slow speed feed can be performed without being influenced by variations of the individual min. starting voltages of the motor at the slow speed feed time. Brake force is further applied to a stop from the time of detecting a prescribed pulse width by a time (t) evaluated by t=mv<2> /2T, where (v) is a speed of the slide part, obtained from a track crossing signal at the time of detecting the prescribed pulse width, while (m) is mass of the slide part, and torque of the motor is denoted by T.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus equipped with a slide feed motor for moving a pickup in the radial direction of a disc when reproducing information recorded on the disc.

[0002]

2. Description of the Related Art As a slide feed motor as described above, a linear motor is used in some middle and high class machines. However, the slide feeding by the linear motor complicates the peripheral circuit for speed control and requires a high-precision slide mechanism, resulting in high cost. Moreover, power consumption increases when trying to realize a high-speed search.

Therefore, in the conventional popular type disk reproducing apparatus, the DC brush motor is used in combination with a rack and pinion mechanism, a ball screw or the like in most of the slide feeding motor of the pickup.

In the slide feed by the DC brush motor, as shown in FIG. 8, an input signal (Tracking Drive Signal: to the following) to a BTL (Balanced Transformer Less) driver 52 for driving the radial actuator coil 51 in the tracking servo loop. , T
The low-pass component is extracted from the RD signal) through the low-pass filter 53, and this signal is used as a slide feed motor D via the slide motor driver 54.
The C brush motor 55 is driven to perform the slide feeding of the slide portion 57 having the pickup 56 mounted thereon.

The DC brush motor 55 as described above is
If a BTL motor driver or the like having a low output impedance is used, the motor coil is connected to the driver output when it is not driven due to the circuit structure, that is, it is in a low impedance state. Therefore, when the drive output from the motor triber is stopped, the brake is applied by the counter electromotive force accompanying the subsequent inertial rotation.

Therefore, with the DC brush motor,
When performing a high-speed search operation by track counting, as shown in FIG. First, the tracking servo is turned off at the start point (point a). B. Start the rotation of the slide feed motor in the specified direction (point b). C. A predetermined value is set in the counter that counts the track cross signal of the tracking error signal (c
point). D. When the counter reaches a predetermined value by the track cross signal, the slide feed motor is stopped (point d). → The back electromotive force brake is applied naturally. E. Wait until the slide is sufficiently stopped by the back electromotive force brake of the slide feed motor and the loss torque of the slide mechanism (the period indicated by e), and turn on the tracking servo (point f). The procedure is as follows. As described above, in the DC brush motor, the high-speed search based on the track count is performed with relatively easy control.

However, in the DC brush motor, since the brush contact exists in the power (current) supply path, the occurrence of sparks is unavoidable, and there is a big problem in durability. Generally, the continuous operating life of a DC brush motor is about 1,000 hours. Therefore, it is possible to use a three-phase brushless motor as the slide feed motor. Such a three-phase brushless motor does not have a brush structure as compared with a DC brush motor, so its durability is 5,000.
It is 0 to 10000 hours, which is 5 to 10 times that of the DC brush motor.

A motor driver for driving the above three-phase brushless motor has a circuit configuration as shown in FIG. 10, for example. That is, a switching circuit including a pair of upper switching transistors Tr1 to Tr3 and lower switching transistors Tr4 to Tr6 is provided corresponding to each of the three-phase motor coils C1 to C3. In addition, the control PNP transistor Tr is provided on each base of the upper switching transistors Tr1 to Tr3.
7 to Tr9 are connected to control PNP transistor
And the emitter of the Tr7 ~Tr9, to the collector of the upper switching transistor Tr1 ~Tr3, motor voltage V _M through the motor voltage supply terminal T23 · T24 each are supplied.

In such a circuit configuration, each coil C1
The actual voltage V _L applied to ~ C3 depends on the upper switching transistors Tr1 to Tr3 and the lower switching transistor Tr.
The voltage drop V _CESAT due to the ON resistance with 4 to Tr6 is reduced from the motor voltage V _M. Also, control PNP transistors Tr7 to Tr9 and the upper switching transistor Tr
Between 1 and Tr3, a diode is provided in place of the external resistor CS in the figure, and as a result, in a motor driver that shares the motor voltage supply terminals T23 and T24,
Furthermore, it is further reduced by the voltage drop V _D across the diode. Therefore, _{V L = V M -2V CESAT (} -V D).

Therefore, even when the motor operates stably with V _L of 1 V or more, the motor voltage V _M is
At least 2.0 to 3.0V is required. Therefore, assuming that the maximum value of the variable range of the motor voltage V _M is 8 V, the dynamic range of the voltage at which the motor can operate is 20 log 8 / in the above three-phase brushless motor.
It becomes about 2 to 20 log 8/3 (12 dB to 8.5 dB). This is much smaller than the DC brush motor of about 20 dB described above.

[0011]

As described above, since the three-phase brushless motor has a smaller dynamic range of the operable voltage of the motor than the DC brush motor, the same rotation as when the DC brush motor is used. If a motor with a number / torque characteristic is used and the same slide feed gear ratio is used, the slide feed speed during high-speed search or track counting is increased to reduce the search time. Causes the problem shown in.

First, as shown in FIG. 11, in the case of the motor A having a small rising time constant Zm _A , its rotation speed /
The torque characteristic is as shown by A in FIG. In the case of the three-phase brushless motor having such characteristics, the track count can be made faster, but as described above, since the operable voltage range is smaller than that of the DC brush motor, the motor voltage at the time of slow-speed slide feed during normal reproduction is high. Can't be lowered. As a result, the acceleration of the slide feed at this time becomes large, which makes it easy to deviate from the margin of the servo characteristic, resulting in an unstable system.

On the other hand, in the motor having the characteristics shown by B in FIGS. 11 and 12, the starting torque is small and the rising time constant Zm _B is large, so that the high speed search by the track count becomes slow. That is, as shown in FIG. 13, EFM (Eight to Fourt) of pits on the disc
een Modulation) Due to the limitation of the upper limit frequency f _LIM determined by the S / N due to noise, when it is attempted to perform track counting until the same area as the A motor (the area indicates the track count number), the time is long. Therefore, the high-speed search by the track count becomes slow.

As described above, when the three-phase brushless motor is used as the slide feed motor, the operable motor drive voltage range is narrower on the low voltage side than the DC brush motor due to the three-phase motor drive circuit. It becomes impossible or difficult to achieve stable servo characteristics at the time of searching and at the time of fine speed feeding during reproduction. Note that D
The C brush motor also causes the same problem when driven at a low voltage.

In a three-phase brushless motor, DC
When a coil is short-circuited like a brush motor and a braking force due to a back electromotive force is generated at the time of stopping, a large number of external parts that form a short circuit corresponding to each coil are required.

On the other hand, in the coil short-circuit type brake by the back electromotive force, the magnetic circuit section, the motor mechanism section, and
In consideration of variations in motor characteristics such as loss torque, it is necessary to set the braking time assuming the worst conditions. Therefore, it is difficult to reduce the braking time during high-speed search and track counting.

Further, when the reverse rotation brake is used to shorten the braking time at the time of track counting, it is necessary to detect the speed of the slide portion to determine the brake release point. A control circuit and the like are separately required, resulting in high cost.

In the high-speed search based on the track count, the following problem occurs in the brake area due to the reverse brake. Generally, as indicated by a solid line in the graph of FIG. 4, a slide speed change point, particularly an acceleration start point (point a)
At the brake start point (point b), the pickup vibrates at its self-resonance frequency and higher-order resonance frequency.
Therefore, no matter what method is used to detect the slide stop, the Q of the radial actuator of the pickup will be detected.
If the acceleration at the brake start point is too large for the (quality factor), or if the load load on the slide part is small and the braking time becomes too short with respect to the torque during reverse braking, the pickup vibration will continue even after the slide part is stopped. The remaining landing accuracy of the track count deteriorates.

The same applies to the above DC brush motor when the reverse brake is also used.

High-speed search by track count
As shown in Fig. 5, targeting a small number of tracks, at this time, a track cross signal is input to the counter for speed control / stop detection during reverse braking of the slide feed motor, and pulse width detection based on this track cross signal is performed. When it is performed, the above-mentioned erroneous detection due to the vibration of the pickup easily occurs. Therefore, the timing to stop the brake is advanced, and the required braking time is not given,
The position where the slide portion stops moves forward, and as a result, the landing accuracy of the track count deteriorates and a singular point occurs.

If the track count is started (tracking servo OFF) when the pickup is not in the free center due to eccentricity of the disk, the vibration of the pickup is increased or the phase is shifted, and the track count is landed. Accuracy deteriorates. Further, even if an erroneous detection occurs due to scratches on the disc, dirt, impact from the outside, etc., the brake may be released at a significantly early point. Even in the DC brush motor, if the reverse brake is used together to shorten the braking time, the same problem as described above occurs.

In the track jump by the kick operation, when the three-phase brushless motor is used to slide-feed by the amount of compensation of the amount of movement of the radial actuator by the kick (hereinafter, this slide-feed is referred to as kick assist), Depending on how the state of the motor was just before the assist of, the amount of slide feed by the kick assist changes significantly.

This is a configuration in which there is no short circuit for short-circuiting each coil when stopped in a three-phase brushless motor (the full-wave drive circuit of the three-phase motor driver in FIG. 10, without connecting a short circuit to the terminal T20). It occurs when assisting kicks,
In this case, since each coil becomes OPEN when the motor is stopped, it is necessary to consider the charging / discharging current of the coil. That is, the slide feed amount by assisting the kick changes depending on how the state of the motor immediately before was.

In the DC brush motor as well, although it depends on the impedance of the short circuit and the impedance of the motor coil, the influence from the time immediately before the operation of the motor to the kick assist starts from around 10 msec or less.

[0025]

In order to solve the above-mentioned problems, a disk reproducing apparatus according to claim 1 of the present invention comprises a slide feed motor for feeding a slide portion having a pickup mounted in a radial direction of the disk, In the disc reproducing apparatus that changes the voltage supplied to the slide feed motor to change the feed speed of the slide portion, when the slide portion is fed at a low speed, the peak voltage value is lower than the DC voltage supplied when the feed speed is high, Further, it is characterized in that a switching control means for low speed feeding is provided for switching control so that a pulsed voltage is supplied to the slide feeding motor.

According to a second aspect of the present invention, there is provided a disc reproducing apparatus including a slide feed motor for feeding a slide portion having a pickup in a radial direction of the disc, and after the slide feed, a voltage in a reverse rotation direction is supplied to the slide feed motor to brake. When it is detected that the pulse width of the track cross signal obtained from the pickup during the braking period has changed until it corresponds to the predetermined feed speed in the disc reproducing device that applies a force to brake, the predetermined pulse width is detected. Let v be the speed of the slide part obtained from the track cross signal of, the mass of the slide part be m, and the motor torque be T, and the time t obtained by t = mv ² / 2T Controls the voltage supplied to the slide feed motor so that braking force is applied to stop the motor. Braking control means is characterized in that provided that.

According to a third aspect of the present invention, there is provided the disc reproducing apparatus according to the second aspect, further comprising guard time storage means for storing each guard time corresponding to the number of tracks to be skipped by one slide feed. If the elapsed time from the start of braking to the detection of the predetermined pulse width does not exceed the guard time corresponding to the number of tracks to jump at this time, wait until this guard time elapses, After that, the braking control means is controlled so that the braking force is further applied for the time t.

According to a fourth aspect of the present invention, there is provided a disc reproducing apparatus including a slide feed motor for feeding a slide portion having a pickup in a radial direction of the disc, and after the slide feed, a voltage in a reverse rotation direction is supplied to the slide feed motor for braking. In a disc reproducing device that applies a force to brake, a slide feed control unit that lowers the voltage supplied to the slide feed motor is provided at an acceleration start point when starting the slide feed and a brake start point that switches to the action state of the braking force. It is characterized by being.

According to a fifth aspect of the present invention, there is provided a disc reproducing apparatus including a slide feed motor for feeding a slide portion having a pickup mounted in the radial direction of the disc, and the slide operation of the slide portion is intermittently switched by energizing the slide feed motor. In a disc reproducing device that intermittently performs,
It is characterized in that intermittent feed control means is provided for setting the voltage supplied to the next slide feed motor in accordance with the time elapsed since the last time the power supply to the slide feed motor was stopped.

[0030]

In the disc reproducing apparatus according to the first aspect,
Pulse width control drive is applied to slide feed during fine speed feed,
Thereby, even if the peak voltage value at this time is relatively high, the acceleration applied to the slide portion can be suppressed to be low. That is, the drivable voltage range of the three-phase brushless motor or the DC brush motor is relatively widened. For this reason, it is possible to secure the feed speed at the time of high-speed feed when supplying the DC voltage, and at the time of fine-speed feed, there is no influence of the variation in the minimum starting voltage of each motor
It becomes possible to perform stable fine speed feeding.

In the disc reproducing apparatus according to the second aspect, the pulse width is detected from the track cross signal, the speed of the slide portion is calculated from this signal, and the additional braking time t is set. In this case, as a braking control means, for example, by incorporating software for performing the above calculation in a microcomputer, a counter port for inputting a track cross signal and a slide feed motor are turned on / off to the outside. It can be constructed simply by using conventional connection ports such as output ports and output ports controlling forward / reverse rotation of the slide feed motor. Therefore, separately control peripheral mechanism and circuit,
For example, FG detection and FV conversion are not required, and it is possible to perform the speed control of the reverse brake relatively stably at the minimum necessary cost.

In the disc reproducing apparatus according to the third aspect, even if the pulse width detection indicating that the slide portion has decreased to the predetermined speed is performed within the preset guard time, the brake releasing process is started. do not do. This eliminates the occurrence of insufficient braking caused by erroneous detection of the pulse width due to scratches on the disc, dirt, disturbance, etc., the speed control of the reverse brake is stably performed, and the landing accuracy of the track count can be improved.

In the disk reproducing apparatus according to the fourth aspect, by lowering the voltage supplied to the motor coil at the speed change point, it is possible to suppress the acceleration acting on the pickup at this time as much as possible, and the pickup is picked up. The generated vibration can be suppressed. As a result, even when the slide feed is controlled by the track cross signal detected by the pickup, the detection error due to the vibration of the pickup is suppressed, and thus more accurate slide speed control is possible.

According to another aspect of the disk reproducing apparatus of the present invention, for example, when assisting a kick, the following motor state is taken into consideration, that is, the energy state accumulated in the motor coil at that time. Supply voltage for slide feeding is set. Therefore, variations in the slide movement amount at the time of assist due to the immediately preceding motor state are suppressed as much as possible, and an accurate slide feed amount can be secured.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following will describe one embodiment of the present invention with reference to FIGS.

As shown in FIG. 2, the disc reproducing apparatus according to this embodiment has a slide portion 2 on which a pickup 1 is mounted. The tracking error signal detected by the pickup 1 is amplified by RF / AMP3 and input to the servo LSI 4 as a tracking error signal TE. Phase compensation / filter AM in this servo LSI 4
The tracking error signal TE is converted into the tracking drive signal TRD through P4a. This signal TR
When D is input to the radial actuator driver 5 along the tracking servo loop, the radial actuator coil 1 provided in the pickup 1
A is energized and tracking servo is performed.

On the other hand, the slide servo loop in the above apparatus is provided with a microcomputer (hereinafter abbreviated as microcomputer) 6. The tracking drive signal TRD is a signal indicating the average deviation amount of the radial actuator coil 1a through the low-pass filter 4b of about 1 to 10 Hz in the servo LSI 4, that is, a Slide Drive signal that moves the slide unit 2 (hereinafter, SLD signal), and is input to the A / D input port of the microcomputer 6 via the A / D input selector switch SW-1.

Further, the above tracking drive signal
TRD passes through a low-pass filter 7 of about 300 to 500 Hz, and high range (disturbance, noise, etc.) that indicates the actual position of the pickup 1 including the eccentricity component of the disc.
Becomes a TRDFS signal from which the signal is removed, and this TRDFS signal is also input to the A / D input port of the microcomputer 6 via the A / D input selector switch SW-1.

The state of the pickup 1 is grasped by the microcomputer 6 from the SLD signal and the TRDFS signal fetched through the AD input port of the microcomputer 6. From V _M control port of the microcomputer 6, V _M control signals for switching and controlling the motor voltage variable circuit 8 is output. In addition, FIG.
The microcomputer 6 outputs an ST / SP signal for starting / stopping the start / stop of the motor and a switching signal (Dir signal) for the rotation direction of the motor to the three-phase motor driver 9 having the same configuration as shown in 0. To be done. A slide feed motor 10 composed of a three-phase brushless motor is connected to the above-mentioned three-phase motor driver 9, and the rotation of the motor 10 causes the slide portion 2 to be slid and fed in the radial direction of the disk.

The microcomputer 6 is further provided with a counter input port to which a track cross signal based on the tracking error signal TE is input. Then, in the microcomputer 6, based on the SLD signal and TRDFS signal and the track cross signal, software that functions as low speed feed switching control means, braking control means, slide feed control means, and intermittent feed control means is installed. It is incorporated. Further, although not shown, a memory serving as a guard time storage means and a timer are incorporated.

Next, the specific control operation at the time of slide feeding controlled by the microcomputer 6 will be divided into fine speed feeding at the time of disc reproduction, high speed search by the track count method, and low speed search by the kick operation. This will be explained sequentially.

[0042] During the fine fast forward during control disc playback during fine fast forward during disc reproduction, in said V _M control signals, switches the motor voltage variable circuit 8 to the low voltage side (2-3 V), AD of the microcomputer 6 A / so that the slide drive (SLD) signal is input to the input control port.
The D input selector switch SW-1 is switched to capture the SLD signal at regular time intervals.

When the value is a predetermined value, that is, when the shift amount of the pickup 1 becomes a predetermined amount, the slide feed direction is judged from the SLD signal and the direction switching signal (Dir signal).
Then, the start / stop control signal as shown in FIG. 1A is sent to the motor driver 9 to drive the slide feed motor 10.

When a pulsed start / stop control signal is input from the microcomputer 6 to the motor driver 9 as shown in FIG. 8A, the coil of the slide feed motor 10 is moved to the coil as shown in FIG. A substantially sawtooth current flows. As you can see from this current waveform,
The pulse width of the stop control signal is made small so as not to exceed the transient response region of the motor current. As a result, the product of the current flowing through the coil is small, and the magnetic energy is relatively small at the same motor voltage V _M. As a result, the acceleration generated in the slide portion is suppressed.

Further, FIG. 6C shows a change in speed of the slide portion 2, and as shown in the figure, by adding a follow-up pulse, it is necessary to increase the instantaneous maximum acceleration above the first pulse. A large amount of slide movement is secured. In the figure, the area that increases with time indicates the movement amount, and the alternate long and short dash line indicates the movement amount of only the first pulse.

Control at High Speed Search by Track Count Method A control procedure at high speed search by the track count method will be described with reference to FIG. First, in the step of "initial setting" shown in S1 in the figure, the number of required track jumps to the target search destination is calculated, and the track count direction is set by the direction switching Dir signal of the microcomputer.

[0047] Then, the voltage V _M applied to the slide feed motor 10, by switching the motor voltage variable circuit 8 in V _M control signal is set to a high voltage side (5~8V),
Slide feed motor 1 with start / stop control signal
Driving of 0 is started (S2). At this time, at the same time, the control signal between the microcomputer 6 and the servo LSI 4 sets the servo LSI 4 in the track count mode and turns off the tracking servo. Then, the start / stop control signal of the microcomputer 6 is started, the slide feed motor 10 is started,
Transition to the track count state.

At this time, the count number calculated in S1 is set in the counter inside the microcomputer 6 to which the track cross signal is input (S3), and based on the track cross signal input in the subsequent slide feeding operation. Track counting is performed, and each count is sequentially subtracted (S4).

When it is determined in step S4 that the count value of the internal counter has reached 0, the motor voltage for starting the reverse brake is the slide feed motor 1
The motor voltage variable circuit 8 is switched so as to be supplied to 0, and at the same time, it is switched in the reverse rotation direction by the direction switching Dir signal (S5). As a result, braking by the reverse brake is started with respect to the slide feed.

At this time, from the table of "minimum required braking time for track count number" obtained in advance by experiment, the guard brake time corresponding to the track count number at this time is set in the guard timer t1. (S6), the internal counter is set to the pulse width detection mode (S7).

Next, it is judged whether the pulse width obtained from the subsequent track cross signal is larger than a predetermined pulse width A, that is, whether the speed of the slide portion has dropped to a value close to a predetermined value (S8) and exceeds A. If it is, it is further determined whether or not the guard timer t1 has reached 0 (S9). That is, even if it is determined based on the track cross signal that the speed of the slide portion has decreased to a predetermined value, if a predetermined time has not elapsed, a result that a predetermined pulse width is detected is output. It is supposed not to. This prevents erroneous detection of the pulse width due to, for example, vibration of the pickup, scratches, dirt on the disc, disturbance or the like.

After that, the speed of the slide portion 2 is calculated based on the point c in FIG. 4, that is, the pulse width when the predetermined pulse width is detected, and the timer t2 is calculated based on the calculated result.
Then, the subsequent brake continuation time is set (S10).
That is, the control until the slide unit 2 stops after that is
Since the pulse width detection based on the track cross signal cannot be accurately performed due to the eccentric component of the disk, the slide unit 2
The time t from the speed of 1 to the stop is calculated by the following formula. That is, the velocity at the point b is v, the mass of the slide portion 2 is m,
The starting torque of the slide feed motor 10 consisting of a three-phase brushless motor as T, and calculates the duration t by the ^{mv 2/2 = T × t} t = mv 2 / 2T. Actually, in consideration of dynamic friction of the input system and the like in T (torque) in the above equation, the time t at which the slide portion 2 is stably stopped is set.

Then, when the above-mentioned duration t has elapsed, the voltage supply to the slide feed motor 10 is stopped (S11, S12). In step S12, a new time is set in the timer t3 at the time of kick operation, which will be described later, but the details will be described later.

[0054] In the above, at the time of high-speed search of the track counting method, an example of performing switching to the high voltage side (5~8V) a motor voltage variable circuit 8 in V _M control signals in FIG. 2, below As described above, in order to reduce the vibration of the pickup 1, it is possible to adopt a control configuration in which the supply voltage during the track counting operation is appropriately switched.

That is, as shown in FIG. 4, the pickup 1 vibrates due to the acceleration from the slide feed motor 10 at the acceleration start point a and the brake start point b, and at the acceleration start point a. When acceleration of the slide portion 2 starts when the amount of deviation from the radial free center of the pickup 1 is large, the vibration amplitude thereof becomes large or the phase of vibration changes. Further, as shown in FIG. 5, when the braking time is shortened, the pulse width detection point is reached before the vibration is substantially reduced. Due to the erroneous detection of the predetermined pulse width detection point c due to these vibrations, the brake area of the track count varies and the landing accuracy deteriorates.

Therefore, as shown in FIG. 2, the signal input to the A / D input port by the AD input switching control signal before the track count is started is changed from the SLD signal to the TRDFS signal, that is, the current pickup 1 signal. Switch to a signal that knows the position, and from this, feed at a fine speed near the free center,
Then track counting can begin. Further, the motor voltage V _M at the start of track counting is switched to the low voltage side by the motor voltage variable circuit 8 and the voltage V _M is raised stepwise after the start of the acceleration of the slide portion 2, whereby the vibration of the pickup 1 during acceleration is increased. Can be suppressed.

Further, the motor voltage V _M at the brake starting point b in FIG. 4 is switched to the low voltage side to suppress the acceleration at the start of braking, and in the case of FIG. 5, the braking time at the time of track counting is shortened. The vibration of the pickup 1 can be reduced as much as possible by preventing it from becoming excessive. As a result, the predetermined pulse width detection point c in FIG. 4 showing the speed reduction of the slide portion 2 is made stable, and the landing accuracy of the track count can be improved. For example, when the disk eccentricity is 50 to 60 μm or less, the landing accuracy can be set to about ± 50 tracks.

Control at low speed search by kick operation Kick assist when the drive circuit of the three-phase brushless motor does not have a function of short-circuiting the motor coil. The amount of movement is greatly affected.

Therefore, in this embodiment, the three-phase motor driver 9 is controlled by the start / stop signal and the direction switching signal Dir from the microcomputer 6 shown in FIG. Assist.

The control procedure at that time will be described with reference to FIG. First, in the "initial setting" of step S21, the number of kicks is calculated, and the calculation result and the kick direction are set. Next, the necessary assist amount corresponding to the number of kicks is read from the table stored in advance (S22). In this table, the relationship of “driving pulse width vs. motor rotation angle” as shown in FIG. 7 is obtained in advance by an experiment, and an assist amount table is created from this. The assist pulse corresponding to the number of kicks is set from this table.

Then, in step S23 of FIG.
It is determined whether or not the kick assist control timer t3 is 0. This timer t3 is used in step S3 described later.
The value set at 0, that is, the value set at the end of the previous kick assist. Therefore, if the set time of the timer t3 has passed after the end of the previous kick assist, and the timer t3 is 0, the step S is performed as it is.
25, and if the set time has not elapsed, in S24, the pulse width of the assist pulse set based on the assist amount table is corrected according to the remaining time at this time, and thereafter, Control goes to step S25.

The above correction corresponds to the presence / absence of accumulation of residual current energy after the energization of the motor coil is stopped. That is, as described above, the three-phase brushless motor is used as the slide feed motor, and at this time, the three-phase full-wave drive circuit does not have a circuit for short-circuiting the motor coil when the motor is stopped, and the immediately preceding motor is used. If the time from the operation to the kick assist is short and there is an influence of the residual energy in the coil, the slide feed amount by the kick assist changes significantly.

[0063] Therefore, keep in store the state immediately before the motor, accumulated in the motor coil were E = LI ^2/2
The energy of (L: motor inductance, I: current flowing in the motor) is calculated, and the pulse width of the assist pulse is corrected. As a result, even if the elapsed time from the previous motor operation is short and the residual energy of the motor coil is not sufficiently self-discharged, stable kick assist can be performed in consideration of the energy storage amount.

In this way, after the correction according to the elapsed time in the timer t3, the kick operation is started (S2).
5). And kick assist started almost at the same time,
The output of the assist pulse is started (S26).
After that, when the timer t4 detects that the predetermined time has elapsed (S27), the kick assist operation is completed (S27).
28), the slide feed motor 10 is stopped.

Thereafter, the length of the kick assist operation period is discriminated (S29), and if it is longer than a predetermined time, an initial value corresponding to the time is set in the kick assist control timer t3 (S30). . Next, wait for the completion of the kick operation in the tracking servo system (S31),
After that, kick end processing is performed (S32), and the kick operation control at this time is ended.

If the previous motor operation was the high speed search based on the track count, the kick assist control timer t3 is set to the initial value in step S12 in FIG.

As described above, in the above embodiment, a highly durable three-phase brushless motor is used as the slide feed motor 10, and a slide feed servo circuit having the above-mentioned control functions is provided. A disk reproducing device is configured.

Particularly, when a three-phase brushless motor is conventionally used as a slide feed motor, the operable motor drive voltage range is limited on the low voltage side by a motor drive circuit as compared with a DC brush motor.
Therefore, there has been a problem that it is impossible or difficult to achieve both the high speed search and the servo characteristic margin at the time of fine speed feeding during reproduction.

On the other hand, in the above embodiment, the pulse width control drive by the software is performed for the slide feed at the time of the fine speed feed, whereby the acceleration applied to the slide portion 2 can be suppressed to a low level even with a relatively high motor voltage. You can do it.

That is, the drivable voltage range of the three-phase brushless motor is relatively widened by the above control. Further, the motor supply voltage V _M that rotates at a very slow speed is used to drive the pulse wave as described above, and the shift amount of the radial actuator 1a is detected and controlled by the A / D input of the microcomputer. It is not affected by the variation in the minimum starting voltage, and stable fine feed can be performed near the free center of the radial actuator.

As a result, it is possible to provide a disc reproducing apparatus which is provided with a highly durable and highly reliable high-speed search and which can stably perform fine speed feeding. If the above control is applied to a slide feed servo with a DC brush motor, a disc reproducing device capable of performing a high-speed search by increasing the feed gear ratio and a high-speed search while lowering the motor voltage can be provided. Is possible.

Further, in the above embodiment, in the high speed search by the track count, when the reverse brake is applied by the three-phase brushless motor after the track count area (the area from point a to point b in FIG. 4) is finished, , The track cross signal is applied to the counter input of the microcomputer 4, the pulse width of the track cross signal is detected, and if it is detected that the slide feed speed has decreased to a predetermined value, then the slide feed speed at that time is detected. T = mv ² / so that the slide part 2 stops completely
2T (m: mass of slide part, T: motor torque, v:
The brake is controlled to continue for a time t determined by the speed of the slide portion).

In this case, only by using the counter port of the microcomputer 6, the output port for turning the slide motor ON / OFF, and the output port for controlling the forward / reverse rotation of the slide motor, a separate peripheral mechanism / circuit for control, for example, FG. It does not require detection and FV conversion, etc., and can control the speed of the reverse brake relatively stably at a minimum cost. Moreover,
The braking area time can be shortened compared to the conventional braking by the reverse activation force in the motor coil short circuit, which enables faster search.

Further, in the above embodiment, in the braking area by the reverse braking of the three-phase motor during the high-speed search by the track counting, when the subsequent braking time is controlled by the detection of the predetermined pulse width, A table of the minimum required braking time correlated with the acceleration time or the specified track count is stored in advance. Even if the predetermined pulse width is detected within the table value of the braking time, that is, the required braking time, the brake release processing is not performed.

As a result, the release of the brake is suppressed and the shortage of the brake is prevented based on the erroneous detection of the pulse width due to the vibration of the pickup in the speed control during braking and the scratches, dirt, and disturbance of the disc. It As a result, the landing accuracy of track count is improved, fail-safe is measured, and a series of operations during seek, that is, track
When moving from the count to the next kick, the number of kicks can be reduced and the average seek time can be shortened.

Further, in the above embodiment, the motor voltage at the speed change point in the track count region (motor acceleration region) and the reverse brake region is lowered in order to suppress the pickup vibration during the high speed search by the track count. We are in control.

That is, in the high-speed search of the track counting method using the three-phase brushless motor as the feed motor, when the speed decrease of the slide portion is detected by the pulse width of the track cross signal, in the track counting area and the braking area. A speed change point of the slide portion 2, that is, a speed difference between the pickup 1 and the slide portion 2 due to vibration of the pickup 1 when acceleration occurs is a problem. In other words, although the speed control is symmetrical with respect to the slide portion 2, the track cross signal obtained from the pickup 1 is used for the speed detection signal, so that accurate vibration control cannot be performed when the vibration of the pickup 1 is large. .

Therefore, as described above, the acceleration of the pickup 1 can be suppressed by decreasing the motor voltage V _M at the speed change point of the slide portion 2 and switching the voltage continuously or stepwise. Further, at the start of track counting, a signal corresponding to the radial deviation of the pickup 1 is passed through the low pass filter 7 to the A of the microcomputer 6.
/ D input port, and by knowing the shift amount of the pickup 1 by this, it is possible to suppress the phenomenon that the vibration becomes large when the shift amount of the pickup 1 is large at the start of track counting, and almost accurate slide speed control Is possible. In particular, by controlling the pickup 1 so that track counting (motor acceleration) is started near the free center in the radial direction, a high-speed search of the track counting method with more stable landing accuracy becomes possible.

Even in the high-speed search of the track count method using the DC brush motor as the slide feed motor, the above control prevents vibration of the pickup, thereby preventing erroneous track count. Further, even when the predetermined pulse width detection is performed in the above-described reverse brake area, the above-described control is used together, so that more stable brake control can be performed.

On the other hand, in the above embodiment, in the assist feed during the kick operation, the motor supply voltage is corrected in accordance with the motor non-operating time immediately before that. That is, when assisting the kick, that is, when the slide unit 2 is moved by the shift of the pickup 1 when the track jump is executed by the shift of the pickup 1, the state of the motor immediately before is stored in software and stored in the coil of the motor. K = assist is performed by making a correction according to E = 1/2 LI ² .

As a result, it is possible to more reliably perform the assist amount that matches the number of kicks. As a result, even when using a general-purpose low-priced 3-phase motor driver without a short brake circuit, stable and highly reliable kick assist can be performed, continuous kick operation can be performed, and seek speed during a short track jump can be improved. It can be configured as a fast disc reproducing device.

Even with a DC brush motor, when the impedance of the short circuit system cannot be lowered so much,
By the control similar to the above, stable assist can be performed. As described above, in the above-described embodiment, the example in which the slide feed motor is configured by the three-phase brushless motor is described, but the present invention can be applied to an apparatus in which the slide feed motor is configured by the DC brush motor. Is.

[0083]

As described above, the disc reproducing apparatus according to the first aspect of the present invention is provided with the slide feed motor for feeding the slide portion having the pickup in the radial direction of the disc, and the voltage supplied to the slide feed motor. In the disc reproducing apparatus in which the feed speed of the slide portion is varied, the peak voltage value is lower than the DC voltage supplied during the high speed feed of the slide portion, and the pulsed voltage is A configuration is provided in which a switching control means for low-speed feeding is provided to perform switching control so as to supply to the slide feeding motor.

As a result, it is possible to secure the feeding speed at the time of high speed feeding, and at the time of fine speed feeding, it is possible to perform stable fine speed feeding without being influenced by the variation of the minimum starting voltage of each motor. .

According to a second aspect of the present invention, there is provided a disc reproducing apparatus including a slide feed motor for feeding a slide portion having a pickup mounted in a radial direction of the disc, and after the slide feed, a voltage in a reverse rotation direction is supplied to the slide feed motor for braking. When it is detected that the pulse width of the track cross signal obtained from the pickup during the braking period has changed until it corresponds to the predetermined feed speed in the disc reproducing device that applies a force to brake, the predetermined pulse width is detected. Let v be the speed of the slide part obtained from the track cross signal of, the mass of the slide part be m, and the motor torque be T, and the time t obtained by t = mv ² / 2T Controls the voltage supplied to the slide feed motor so that braking force is applied to stop the motor. That the brake control means is configured to are provided.

As a result, as the braking control means, for example, a microcomputer can be configured to have built-in software for performing the above-mentioned calculation and the like.
Just use the counter port of the microcomputer and the output port that turns the slide feed motor ON / OFF and the output port that controls the forward / reverse rotation of the slide feed motor.
In addition, it does not require any peripheral mechanism or circuit for control. Therefore, there is an effect that the speed control of the reverse brake can be relatively stably performed with the minimum necessary cost.

According to a third aspect of the present invention, there is provided the disc reproducing apparatus according to the second aspect, further comprising guard time storage means for storing each guard time corresponding to the number of tracks to be skipped by one slide feed. If the elapsed time from the start of braking to the detection of the predetermined pulse width does not exceed the guard time corresponding to the number of tracks to jump at this time, wait until this guard time elapses, After that, the braking control means controls so that the braking force is further applied for the time t.

This eliminates the occurrence of insufficient braking caused by erroneous detection of the pulse width due to scratches on the disk, dirt, disturbance, etc., and speed control of the reverse brake is stably performed.
This has the effect of improving the landing accuracy of the track count.

According to a fourth aspect of the present invention, there is provided a disc reproducing apparatus including a slide feed motor for feeding a slide portion having a pickup mounted in a radial direction of the disc, and after the slide feed, a voltage in a reverse rotation direction is supplied to the slide feed motor for braking. In a disc reproducing device that applies a force to brake, a slide feed control unit that lowers the voltage supplied to the slide feed motor is provided at an acceleration start point when starting the slide feed and a brake start point that switches to the action state of the braking force. It is a configured structure.

As a result, the acceleration acting on the pickup at the speed change point can be suppressed as much as possible, and the vibration of the pickup can be suppressed. Therefore, even when the slide feed is controlled by the track cross signal detected by the pickup, the detection error due to the vibration shift amount of the pickup is suppressed, and as a result, more accurate slide speed control can be performed. .

According to a fifth aspect of the present invention, there is provided a disc reproducing apparatus including a slide feed motor for feeding a slide portion having a pickup mounted thereon in a radial direction of the disc, and the electric power supplied to the slide feed motor is intermittently switched to perform a slide operation of the slide portion. In a disc reproducing device that intermittently performs,
The configuration is provided with intermittent feed time control means for setting the supply voltage to the next slide feed motor in accordance with the elapsed time from the time when the power supply to the slide feed motor was stopped last time.

As a result, for example, when assisting a kick, variations in the amount of slide movement during assist due to the immediately preceding motor state are suppressed as much as possible, and an accurate slide feed amount can be secured.

[Brief description of drawings]

FIG. 1 is a time chart showing a correspondence relationship between a start / stop signal at a fine speed feed, a current flowing in a motor coil, an angular velocity of a motor, and a velocity of a slide portion in a disc reproducing apparatus according to an embodiment of the present invention. is there.

FIG. 2 is a control block diagram showing a main configuration of the disc reproducing apparatus.

FIG. 3 is a flowchart showing a control procedure at the time of high-speed search by a track counting method in the disc reproducing apparatus.

FIG. 4 is a graph for explaining changes in the feed speed of the slide unit, the speed of the pickup unit, and the track count frequency during high-speed search by the track count method.

FIG. 5 is a graph for explaining changes in the feed speed of the slide unit and the speed of the pickup unit when a short track is counted.

FIG. 6 is a flowchart showing a control procedure at a low speed search by a kick operation in the disc reproducing apparatus.

FIG. 7 is a graph showing a relationship between a motor rotation angle and a drive pulse width, which is a reference when creating a table of a motor supply voltage set during a low speed search by the kick operation.

FIG. 8 is a control block diagram showing a main configuration of a conventional disc reproducing apparatus.

FIG. 9 is a time chart showing an operation during a high-speed search by conventional track counting.

FIG. 10 is a circuit diagram showing an example of a configuration of a motor driver that drives a three-phase brushless motor.

FIG. 11 is a graph for explaining a starting characteristic in a three-phase brushless motor.

FIG. 12 is a graph for explaining Tokule-rotational speed characteristics in a three-phase brushless motor.

FIG. 13 is a graph for explaining the relationship between the track count frequency and the elapsed time until the count ends in the track count method.

[Explanation of symbols]

1 Pickup 2 Slide part 6 Microcomputer (low speed feed switching control means, braking control means, slide feed control means, intermittent feed control means, guard time storage means) 10 slide feed motor

Claims (5)

[Claims] 1. A disc reproducing apparatus comprising a slide feed motor for feeding a slide portion having a pickup mounted in a radial direction of a disc, and varying a supply voltage to the slide feed motor to vary a feed speed of the slide portion. When the slide portion is fed at a low speed, the low-speed feed switching control means for controlling the switching so that the peak voltage value is lower than the DC voltage supplied at the high-speed feed and a pulsed voltage is supplied to the slide feed motor. A disk reproducing device characterized by being provided. 2. A disc reproducing device comprising a slide feed motor for feeding a slide portion having a pickup mounted in a radial direction of the disc, and supplying a voltage in a reverse rotation direction to the slide feed motor after the slide feed to apply a braking force for braking. When the device detects that the pulse width of the track cross signal obtained from the pickup during the braking period has changed until it corresponds to the predetermined feed speed, the slide obtained from the track cross signal at the time of detecting the predetermined pulse width is detected. Part speed v
Further, assuming that the mass of the slide portion is m and the motor torque is T, the braking force is further applied from the time when the predetermined pulse width is detected for a time t obtained by t = mv ² / 2T, and the vehicle is stopped. A disc reproducing apparatus characterized in that a braking control means for controlling a voltage supplied to a slide feed motor is provided. 3. A guard time storage means for storing each guard time according to the number of tracks to be jumped over by one slide feed is further provided, and the progress from the start of braking to the detection of the predetermined pulse width. When the time does not exceed the guard time corresponding to the number of tracks to jump over at this time, wait until this guard time elapses, and then apply the braking force for the time t. 3. The disc reproducing apparatus according to claim 2, wherein the braking control means controls the braking control means. 4. A disc reproducing system comprising a slide feed motor for feeding a slide portion having a pickup mounted in a radial direction of the disc, and supplying a voltage in a reverse rotation direction to the slide feed motor after the slide feed to apply a braking force for braking. The apparatus is characterized by being provided with slide feed control means for lowering the voltage supplied to the slide feed motor at an acceleration start point at the time of starting the slide feed or a brake start point at which the brake force is switched to an applied state. Disc player. 5. A disc reproducing apparatus comprising a slide feed motor for feeding a slide portion having a pickup mounted thereon in a radial direction of the disc, and intermittently switching the power supply to the slide feed motor to intermittently perform the sliding operation of the slide portion. Disc playback, characterized in that the device is provided with intermittent feed control means for setting the supply voltage to the next slide feed motor in accordance with the time elapsed since the last stop of power supply to the slide feed motor. apparatus.