JP2002074819A - Disk damping system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a rotating speed of a spindle motor with accuracy even when using an IC of a circuit configuration difficult to detect the rotating speed of a disk using a synchronous signal. SOLUTION: In a disk damping system comprising a tracking means 7 for allowing a pickup 3 to follow up a track based on a tracking error signal 32, and a spindle control means 11 for controlling the rotation of a spindle motor 2, the tracking means 7 is provided with a rotating speed calculation means 8 for obtaining a rotating speed of a disk 1 on the basis of a variation period of the tracking error signal 32 level in the state in which the tracking means 7 halts the operation to allow the pickup 3 to follow up the track, and the spindle control means 11 reduces the rotating speed of the spindle motor 2 based on the calculation result of the rotating speed calculation means 8 when stopping the rotation of the spindle motor 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for reproducing a disc such as a DVD or a CD, and more particularly, to a reproducing apparatus for reproducing a disc such as a DVD or a CD.
The present invention relates to a disk braking device that obtains a rotation speed of a disk from a cycle of a level change of a tracking error signal when tracking is stopped, and controls to stop the rotation of the disk based on the obtained rotation speed.

[0002]

2. Description of the Related Art When stopping the rotation of a disk,
A configuration is used in which the rotation of the spindle motor is rapidly reduced by applying a braking voltage of the opposite polarity to the spindle motor. Therefore, if the period for applying the braking voltage is too long, the spindle motor may rotate in the reverse direction. On the other hand, if the period during which the braking voltage is applied is too short, the deceleration is not sufficient, and the disk may rotate on the disk tray and damage the disk. For this reason, conventionally, an FG signal generating means for generating an FG signal indicating the rotation speed is provided in the spindle motor, and when the rotation speed indicated by the FG signal is reduced to a predetermined rotation speed, the application of the braking voltage is stopped. I was trying to do it.

However, the provision of the FG signal generating means complicates the apparatus and increases the cost of the apparatus. For this reason, a conventional technique for reducing the rotation speed of a disk without providing an FG signal generating means is disclosed in Japanese Patent Laid-Open Publication No. Hei.
No. 183064. That is, in this technique, there is provided a position detecting means for obtaining the reading position of the pickup at the time of generation of the stop command as position information on the radius of the disk. Further, a control means for applying a reverse rotation force to the spindle motor only during a period corresponding to the obtained position information is provided. For this reason, the period during which the reverse rotation force is applied to the spindle motor changes in accordance with the rotation speed of the spindle motor, so that the rotation of the spindle motor can be stopped accurately (the first conventional technique). Technology).

In the prior art proposed in Japanese Patent Application Laid-Open No. 1-128263, the following configuration is disclosed. That is, in this technique, the pattern length of the synchronization signal in the EMF signal is detected, and from the detected pattern length,
The rotation speed of the CD is detected. Then, when the detected rotation speed becomes a rotation speed of 1/3 of the specified value, the operation of the timer is started. Next, when the timer finishes the time counting operation, the application of the reverse voltage to the spindle motor is stopped (referred to as a second related art).

[0005]

However, when the first prior art is used, the following problems have occurred. That is, the time at which the application of the reverse rotation force to the spindle motor is stopped is the time after the period obtained by the calculation has passed. On the other hand, there are individual variations in the characteristics of the spindle motors. For this reason, the degree of deceleration of the spindle motor when the reverse rotation force is applied varies depending on the device. As a result, the rotation speed of the spindle motor when the application of the reverse rotation force is stopped may be different for each device. Therefore, the period from when the application of the reverse rotation force is stopped to when the rotation of the spindle motor stops is varied depending on the apparatus. Therefore, it is necessary to allow sufficient time for the disk to be lowered to the tray position after the application of the reverse rotation force is stopped. As a result, the period from when the stop operation is performed to when the disk can be taken out has been long.

When the second conventional technique is used,
The following problems have occurred. That is, in order to detect the pattern length of the synchronization signal in the EMF signal, an IC
It is necessary to provide a circuit for detecting the pattern length of the synchronization signal inside the IC, or take out the synchronization signal outside the IC and detect the pattern length of the taken-out synchronization signal.
Therefore, when an IC that does not have a circuit for detecting the pattern length of the synchronization signal and does not have a terminal for extracting the synchronization signal to the outside is used, the present invention is applicable. It was difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to detect the rotation speed of a spindle motor based on a period of a level change of a tracking error signal when tracking is stopped. By performing deceleration control of the spindle motor based on the detected rotational speed, even when using an IC having a circuit configuration in which it is difficult to detect the rotational speed of the disk using the synchronization signal,
An object of the present invention is to provide a disk braking device capable of accurately reducing the rotation speed of a spindle motor.

In addition to the above object, a coefficient based on the correspondence between the rotation speed of the spindle motor before the rotation speed is reduced and the period of the level change of the tracking error signal is obtained. An object of the present invention is to provide a disk braking device that can calculate a rotational speed with high accuracy even when a disk is eccentric by calculating a rotational speed from a cycle of a level change and the coefficient. .

In addition to the above object, when a predetermined period elapses after the tracking is stopped, the period used for calculating the coefficient is detected, so that the driving of the tracking actuator is stopped. An object of the present invention is to provide a disk braking device capable of removing an error.

[0010]

According to the present invention, there is provided a disk brake apparatus comprising: a pickup for detecting data recorded along a spiral track of a disk rotated by a spindle motor; The present invention is applied to a reproducing apparatus including tracking means for causing a pickup to follow the track based on an error signal, and spindle control means for controlling rotation of a spindle motor, and the tracking means stops the operation of causing the pickup to follow the track. Rotation speed calculating means for determining the rotation speed of the disk based on the period of the level change of the tracking error signal in the state in which the rotation of the spindle motor is stopped. Spindle model based And slow down the rotation speed of the motor.

That is, the cycle of the level change of the tracking error signal when the tracking is stopped has a value corresponding to the rotation speed of the spindle motor. Therefore, the rotation speed obtained by the rotation speed calculation means is a value that accurately indicates the rotation speed of the spindle motor.

In addition to the above configuration, the rotation speed calculating means may stop the operation of causing the pickup to follow the track before the spindle control means starts to reduce the rotation speed of the spindle motor. A relationship coefficient indicating the relationship between the cycle of the level change of the tracking error signal in the state where the spindle motor is rotated and the rotation speed of the spindle motor before the spindle control unit starts to reduce the rotation speed of the spindle motor. When the rotation speed is reduced, the rotation speed of the spindle motor is calculated from the obtained relation coefficient and the period of the level change of the detected tracking error signal.

That is, the correspondence between the period of the level change of the tracking error signal and the rotation speed of the spindle motor changes according to the eccentricity of the disk. On the other hand, the relation coefficient is a value for correcting the above-mentioned correspondence that changes according to the eccentricity of the disk. For this reason, the rotation speed of the spindle motor calculated from the relationship coefficient and the period of the level change of the detected tracking error signal is a value from which the change in the correspondence caused by the eccentricity of the disk is removed.

In addition to the above configuration, the rotation speed calculating means detects a cycle used for calculating the relation coefficient when a predetermined time has elapsed after the tracking means stopped the operation of causing the pickup to follow the track. Is going.

That is, when the tracking means stops the operation of causing the pickup to follow the track, the driving of the tracking actuator is stopped. As a result, the correction force of the actuator applied to the pickup becomes zero, and the detection position of the pickup moves in the radial direction. However, the time when the predetermined period has elapsed is the time at which the movement of the detection position of the pickup in the radial direction ends and the detection position stops at a constant position in the radial direction.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. FIG. 1 is a block diagram showing an electrical configuration of a disc reproducing apparatus using one embodiment of a disc braking apparatus according to the present invention.
1 shows a DVD reproducing apparatus capable of reproducing D and DVD.

In FIG. 1, a spindle motor 2 is a motor for rotating a DVD (disc) 1 so that a linear velocity is constant. The pickup 3 is a block that detects data recorded along a spiral track formed on the DVD 1 using a laser beam and sends the data to an analog signal circuit 4 (tracking actuator, focusing Actuators and sledge mechanism are not shown).

The analog signal circuit 4 is a block that generates a focusing error signal 31 and a tracking error signal 32 by amplifying and calculating a signal transmitted from the pickup 3. Then, the generated focusing error signal 31 is sent to the tracking means 7. Further, it sends a tracking error signal 32 to the tracking means 7 and the rotation speed calculating means 8. In addition, while generating a signal indicating data,
The data signal obtained by binarizing this signal is converted to a digital processing circuit 6.
To send to.

The digital processing circuit 6 is a block for reading data recorded on the DVD 1 by performing decoding processing and error correction on the data signal transmitted from the analog signal circuit 4. Then, the read data is sent to the D / A converter 5. Further, the clock signal reproduced based on the data signal is transmitted to the servo unit 2.
3 Also, data indicating the read frame is sent to the control unit 12.

The D / A converter 5 is a block that converts data sent from the digital processing circuit 6 into an analog signal representing an image and an analog signal representing audio, and sends the converted signal to the outside.

The tracking means 7 is a block for driving the actuator of the pickup 3 based on the focusing error signal 31 and the tracking error signal 32 to cause the pickup 3 to follow the track of the DVD 1. When an instruction to stop tracking is issued from the rotation speed calculating means 8, the tracking operation is stopped by stopping the driving of the tracking actuator.

The spindle control means 11 rotates the spindle motor 2 based on the clock signal (reproduced clock signal) sent from the digital processing circuit 6 and a reference clock (not shown) in accordance with the detected position of the pickup 3. It is a block for rotating at speed. When stopping the rotation of the spindle motor 2, the rotation speed of the spindle motor 2 is reduced based on the calculation result of the rotation speed calculation means 8. For this purpose, a servo unit 23, a stop unit 22, and a drive circuit 21 are provided.

More specifically, the drive circuit 21 includes the servo unit 2
3 is an amplifier circuit for driving the spindle motor 2 with a drive current corresponding to the output of the spindle motor 2. Stop means 2
When the brake signal is transmitted by the motor 2, an output for driving in the reverse rotation direction is supplied to the spindle motor 2. The servo means 23 controls the rotation of the spindle motor 2 via the drive circuit 21 so that the clock signal sent from the digital processing circuit 6 is phase-synchronized with the reference clock, thereby detecting the DVD 1 and detecting the pickup 3. The block rotates at a rotation speed corresponding to the position.

The stopping means 22 is a block for performing control to stop the rotation of the spindle motor 2 based on the calculation result of the rotation speed calculating means 8. That is, when the rotation speed calculating means 8 instructs the stop of the rotation, a braking signal is transmitted to the drive circuit 21 so that
A reverse rotation force is applied to the spindle motor 2 to reduce the rotation speed of the spindle motor 2. During the deceleration, when the rotation speed calculated by the rotation speed calculation means 8 indicates a sufficiently reduced speed (when the rotation speed has decreased to a speed indicating the stop of the deceleration), the braking signal is output. The transmission is stopped, and the driving by the driving circuit 21 in the reverse rotation direction is stopped.

The rotation speed calculation means 8 is a block for calculating the rotation speed of the DVD 1 based on the period of the level change of the tracking error signal 32 in a state where the tracking means 7 stops the operation of causing the pickup 3 to follow the track. I have. Then, the calculated rotation speed is sent to the stopping means 22.

More specifically, the rotation speed calculation means 8 performs an operation before the spindle control means 11 starts to reduce the rotation speed of the spindle motor 2 and the tracking means 7 causes the pickup 3 to follow the track. In the stopped state, the time of the level change of the tracking error signal 32 is detected by sequentially detecting the time when the tracking error signal 32 crosses zero. And
From the relationship between the detected cycle and the rotational speed of the spindle motor 2 (given from the control means 12) corresponding to the detected position of the pickup 3, the cycle and the spindle motor 2
The relationship coefficient with the rotation speed is determined.

Next, a deceleration instruction is sent to the spindle control means 11. In response to this instruction, when the spindle control means 11 is performing control to reduce the rotation speed of the spindle motor 2, the tracking means 7
The operation of detecting the cycle of the level change of the above is repeated. Then, every time the cycle of the level change is detected, the rotation speed of the spindle motor 2 is calculated from the detected cycle and the obtained relation coefficient, and the calculated rotation speed is sent to the stopping means 22.

When detecting the period of the level change of the tracking error signal 32, the rotation speed calculating means 8 gives an instruction to stop the tracking to the tracking means 7 to obtain the relation coefficient. ,
When 100 mS) has elapsed, the cycle is detected (the reason will be described later).

The input section 13 is a block to which an instruction such as start of reproduction, stop of reproduction, or power on / off is input. For this reason, a plurality of key switches (playback start instruction key, open / close key of disk tray 2, power key, etc.) provided on the operation panel,
A unit for receiving an infrared signal transmitted from a remote controller (not shown) is provided.

The control means 12 is a block for controlling main operations as a DVD reproducing device. For this reason, when an instruction to stop reproduction is input to the input unit 13, the rotation speed of the spindle motor 2 is calculated based on frame data transmitted from the digital processing circuit 6. Then, the calculated rotation speed is used as the rotation speed calculation means 8.
To send to.

The rotation speed calculating means 8 and the stopping means 2
The control unit 12 and the control unit 12 are mainly constituted by a microcomputer. Also, the digital processing circuit 6 and the servo means 23 are divided into a plurality of dedicated ICs.
It consists of.

FIG. 2 is a flowchart showing the main operation of the embodiment, FIG. 3 is an explanatory diagram showing the locus of the detection position of the pickup 3 when tracking is stopped, and FIG. 4 is a tracking error when tracking is stopped. Signal 3
It is explanatory drawing which shows the level change of 2 typically. The operation of the embodiment will be described with reference to these drawings as necessary.

When it is necessary to stop the rotation of the DVD 1 rapidly, such as when an instruction to open the tray is input during the reproduction of the DVD 1, the control means 12
Stops the drive of the spindle motor 2 by the drive circuit 21 via the stopping means 22 (step S1). Further, the control means 12 calculates the detection position of the pickup 3 in the radial direction of the DVD 1 based on the data of the frame notified by the digital processing circuit 6 at the time when the instruction is input. Then, the rotation speed of the spindle motor 2 is calculated based on the calculated detection position. Next, the calculated rotation speed is sent to the rotation speed calculation means 8 (step S2).

The rotation speed calculating means 8 notified of the rotation speed of the spindle motor 2 determines that the rotation of the spindle motor 2 has stopped, and instructs the tracking means 7 to stop tracking. The tracking means 7 instructed to stop the tracking stops driving of the tracking actuator of the pickup 3 (Step S).
3). As a result, the tracking actuator is
The application of the correction force given to the pickup 3 is stopped.
As a result, the detection position of the pickup 3 moves in the radial direction by the track forced by the correction force of the actuator, and then stops at a constant position in the radial direction.

That is, when the tracking means 7 stops driving the tracking actuator, the detection position of the pickup 3 moves in the radial direction,
It will stop at a certain position. For this reason, after sending the tracking stop instruction to the tracking means 7, the rotation speed calculating means 8 moves the detection position of the pickup 3 in the radial direction and then stops at a fixed position for a predetermined time. A standby (100 mS in this embodiment) is performed (step S4). When the waiting for a predetermined time is completed, the rotation speed calculating means 8 detects the period of the tracking error signal 32.

A spiral curve 41 shown in FIG. 3 schematically shows a track formed on the DVD 1. A circle 42 indicated by a broken line indicates a locus of the detection position of the pickup 3 when the tracking is stopped.

That is, the detection position of the pickup 3 is
When stopping at a fixed position in the radial direction, DVD1
When the is rotated, the track crosses the detection position. On the other hand, due to an error when the DVD 1 is fixed to the axis of the spindle motor 2 and an error when the DVD 1 is formed, the track of the DVD 1 rotates eccentrically with respect to the rotation center of the spindle motor 2. This figure shows a case where the above-described eccentricity occurs. Each time the DVD 1 makes one rotation, the track crosses the detection position of the pickup 3 ten times.

That is, when the detection position of the pickup 3 is stopped at a constant position in the radial direction, the DVD 1
The number of tracks that cross the detection position every time the
The value differs depending on the amount of eccentricity. Also, the number of crossing tracks increases as the eccentricity increases. In addition,
The number becomes the minimum when the eccentricity is 0. In this case, the value becomes one.

Therefore, even when the rotation speed of the DVD 1 is the same, the level change of the tracking error signal 32 changes as shown in FIG. 4 when the eccentricity of the DVD 1 is small, as shown in FIG. When the eccentricity of the DVD 1 is large, the change is as shown in 32b.

From the above, the rotational speed calculating means 8
Based on the rotation speed Na (the rotation speed of the spindle motor 2 when the stop instruction is input) given from the control means 12, the DVD 1 calculates, for example, a period U required for two rotations. Then, in this period U, the number of times that the tracking error signal 32 crosses the 0 level is detected. (Since the time intervals in which the tracking error signal 32 crosses the 0 level are unequal, the period U is the period required for one rotation. It is desirable to be an integer multiple). Then, the average value ta of the period of the level change of the tracking error signal 32 is calculated from the detected number of times (step S5).

Next, from the calculated average value ta and the rotation speed Na given by the control means 12, the rotation speed calculation means 8 calculates a relation coefficient K by calculation (K = ta × Na) ( Step S6). The rotation speed calculating means 8 having calculated the relation coefficient K gives the stop means 22 an instruction to start deceleration. Stop means 22 given this instruction,
By sending a braking signal to the drive circuit 21, an output that applies a reverse rotational force to the spindle motor 2 is output to the drive circuit 21.
To start the deceleration of the rotation speed of the spindle motor 2 (step S7).

After the stop means 22 starts the control for reducing the rotation speed of the spindle motor 2, the rotation speed calculation means 8 detects the tracking error signal 32 by sequentially detecting the time of the zero cross point, thereby obtaining the tracking error signal. The average value of the 32 level change periods is detected (step S8). Then, every time the average value tb of the period is detected, the calculation of (Nb = K / tb) is performed.
The rotation speed Nb of the DVD 1 at each time is calculated. Then, the calculated rotation speed Nb is sent to the stopping means 22 (step S9).

The stop means 22 controls the rotation speed Nb sent from the rotation speed calculation means 8 to control the deceleration (control of applying a reverse rotation force to the spindle motor 2 by sending a braking signal to the drive circuit 21). It is determined whether the rotation speed has decreased to the stop speed (step S10). When the rotation speed Nb sent from the rotation speed calculating means 8 is higher than the rotation speed at which the control is stopped, the deceleration is continued. Therefore, in this case, the operations of steps S8 to S10 are repeated. When the rotation speed Nb sent from the rotation speed calculating means 8 has decreased to the rotation speed at which the deceleration is stopped, the sending of the braking signal is stopped.
The control for applying the reverse rotation force to the spindle motor 2 is stopped (step S11). Therefore, hereinafter, DVD1
Stops rotation quickly due to frictional force or the like.

The present invention is not limited to the above-described embodiment, and includes a pickup for detecting data recorded along a spiral track of a disk rotated by a spindle motor, and a pickup based on a tracking error signal. The present invention can be similarly applied to any other device (for example, a device that reads a CD-ROM or a DVD-ROM) having a configuration including a tracking unit that tracks a track.

A method for acquiring the rotation speed of the spindle motor 2 when a stop instruction is input is described below.
A case has been described in which the detection position of the pickup 3 in the radial direction is obtained from the data indicating the frame, and the rotation speed of the spindle motor 2 is calculated from the obtained detection position. However, the rotation speed is obtained by any other method. Can be a method.

[0046]

As described above, the disk braking device according to the present invention uses a pickup for detecting data recorded along a spiral track of a disk rotated by a spindle motor and a tracking error signal. The present invention is applied to a reproducing apparatus having tracking means for causing a pickup to follow the track, and spindle control means for controlling rotation of a spindle motor, wherein tracking in a state in which the tracking means stops the operation of causing the pickup to follow the track is stopped. A rotation speed calculating means for calculating a rotation speed of the disk based on a cycle of the level change of the error signal; and a spindle control means for stopping the rotation of the spindle motor based on a calculation result of the rotation speed calculation means when stopping the rotation of the spindle motor. Rotation speed And let me fast. That is, the cycle of the level change of the tracking error signal when the tracking is stopped has a value corresponding to the rotation speed of the spindle motor. For this reason, since the rotation speed obtained by the rotation speed calculating means is a value that accurately indicates the rotation speed of the spindle motor, an IC having a circuit configuration that makes it difficult to detect the rotation speed of the disk using the synchronization signal is used. In some cases, the rotation speed of the spindle motor can be accurately reduced.

Further, the rotation speed calculating means may be arranged to operate before the spindle control means starts to reduce the rotation speed of the spindle motor and in a state where the tracking means stops the operation of causing the pickup to follow the track. A relationship coefficient indicating the relationship between the cycle of the level change of the tracking error signal and the rotation speed of the spindle motor before the spindle control unit starts to reduce the rotation speed of the spindle motor is obtained. When the speed of the spindle motor is decelerated, the rotational speed of the spindle motor is calculated from the obtained relation coefficient and the cycle of the level change of the detected tracking error signal. That is, the correspondence between the period of the level change of the tracking error signal and the rotation speed of the spindle motor changes according to the eccentricity of the disk. On the other hand, the relation coefficient is a value for correcting the above-mentioned correspondence that changes according to the eccentricity of the disk. For this reason, the rotation speed of the spindle motor calculated from the relationship coefficient and the period of the level change of the detected tracking error signal is a value from which the change in the correspondence caused by the eccentricity of the disk has been removed.
Even when the disk is eccentric, the calculated rotation speed can be set to a value with high accuracy.

Further, the rotation speed calculating means detects a cycle used for calculating the relation coefficient when a predetermined time has elapsed after the tracking means stopped the operation of causing the pickup to follow the track. . Therefore, even when the force of the actuator applied to the pickup becomes zero and the detection position of the pickup moves in the radial direction, the movement of the detection position of the pickup in the radial direction ends at the time when the predetermined period has elapsed. Since the time to stop at a certain position is reached, it is possible to remove an error caused by stopping the driving of the tracking actuator.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of a disc reproducing apparatus using one embodiment of a disc braking apparatus according to the present invention.

FIG. 2 is a flowchart showing a main operation of the embodiment.

FIG. 3 is an explanatory diagram showing a trajectory of a detection position of a pickup when tracking is stopped.

FIG. 4 is an explanatory diagram schematically showing a level change of a tracking error signal when tracking is stopped.

[Explanation of symbols]

Reference Signs List 1 DVD (disk) 2 spindle motor 3 pickup 7 tracking means 8 rotation speed calculation means 11 spindle control means 32 tracking error signal 41 track 42 track of detection position of pickup when tracking is stopped

Claims (3)

[Claims] 1. A pickup for detecting data recorded along a spiral track of a disk rotated by a spindle motor, a tracking means for causing the pickup to follow the track based on a tracking error signal, and a spindle motor And a spindle control means for controlling the rotation of the disc, wherein the tracking means stops the operation of causing the pickup to follow the track. A rotating speed calculating means for determining a rotating speed, wherein the spindle control means, when stopping the rotation of the spindle motor, reduces the rotating speed of the spindle motor based on the calculation result of the rotating speed calculating means. Braking device. 2. The method according to claim 1, wherein the rotation speed calculating means determines a tracking error before the spindle control means starts to reduce the rotation speed of the spindle motor and the tracking means stops the operation of causing the pickup to follow the track. The spindle control means obtains a relationship coefficient indicating a relationship between the cycle of the signal level change and the rotation speed of the spindle motor before the spindle control means starts to reduce the rotation speed of the spindle motor, and the spindle control means reduces the rotation speed of the spindle motor. 2. The disk braking device according to claim 1, wherein, when performing the rotation, the rotation speed of the spindle motor is calculated from the obtained relation coefficient and the period of the level change of the detected tracking error signal. 3. The method according to claim 1, wherein the rotation speed calculating means detects a cycle used for calculating the relation coefficient when a predetermined time has elapsed after the tracking means stopped the operation of causing the pickup to follow the track. 3. The disk braking device according to claim 2, wherein