JPH03292674A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To surely stop the rotation of a disk by detecting the rotation direction by a signal obtained by A/D conversion of the impressed voltage of a spindle motor to impress a voltage of the opposite rotation direction to the spindle motor at the time of not reading out a signal from the disk. CONSTITUTION:The signal read out by a pickup 5 is inputted to a controller 1 through a signal processing device 2, and the controller 1 discriminates whether the signal is read out by the pickup 5 at present or not. When the mode is switched to the stop mode in the case of the absence of the read signal, the rotation direction of a spindle motor 6 is discriminated by the signal from an A/D converter 10, and the voltage of the opposite rotation direction is impressed for a prescribed time to brake the sindle motor 6. Thus, disk rotation is surely stopped though the read signal of the disk is not outputted from the pickup 5.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a disc playback device for CDs, laser discs, and the like.

<Prior Art> In a disc playback device, a disc is rotated by a spindle motor. Although this spindle motor is sometimes provided with a Hall element, a tacho generator, etc. to detect its rotation direction and rotation speed, generally, a rotation detection sensor is not provided in many cases from the viewpoint of cost reduction.

As described above, in a disc playback device without a rotation detection sensor, the following operation is performed in order to stop the disc rotation from the normal play mode. That is,
A reverse rotation voltage is applied to a spindle motor that is rotating in the forward direction, the period of the read signal from the disk at that time is measured, and the deceleration of the disk rotation is detected by detecting that the period is longer than the normal period. , stop applying the reverse rotation voltage. This applies the brakes to the rotating disc and puts it into stop mode.

<Problem to be solved by the invention> However, in the above-mentioned conventional disc playback device, if the disc signal cannot be read for some reason,
There was a problem that the brake operation of the disc could not be performed smoothly. Inability to read data occurs when the pickup moves outside the signal surface due to scratches or vibrations on the disc. In such cases, the disc is usually in a runaway state, such as spinning at high speed and in the opposite direction. However, if a voltage is applied in the reverse rotation direction while the disk is rotating in the reverse direction, runaway may be further accelerated.

Means for Solving the Problems> The present invention has been made to solve the above-mentioned conventional problems, and includes a means for detecting whether or not a signal is being read from a disk, and a means for detecting whether or not a signal is being read from a disk, and for controlling the voltage applied to a spindle motor to A. /D
When the signal from the disk is not being read out, the rotation direction is detected by the signal from the A/D conversion means, and based on the detection result, a voltage in a rotation direction opposite to the rotation direction is detected. The basic feature is that the motor is provided with means for applying voltage to the spindle motor.

Function> Detects whether or not signals are being read from the disk, and when signals are not being read from the disk, determines the rotation direction of the spindle motor based on the signal obtained by A/D converting the voltage applied to the spindle motor. . Then, a voltage is applied for a certain period of time in a rotation direction opposite to the rotation direction to brake the spindle motor. This makes it possible to reliably apply the brake to the spindle motor even when the signal from the disk cannot be read.

<Example> Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, a control device 1 is mainly composed of a microcomputer, and is configured to control a pickup 5 and a spindle motor 6, which is a DC motor, via a servo device 3 and a driver 4. The disk is rotated by a spindle motor 6 and its information is read out by a pickup 5. The read signal is processed by the signal processing device 2, converted into an analog signal by the D/A converter 7, and outputted as audio from the speaker 9 via the amplifier 8.

The voltage applied to the spindle motor 6 by the driver 4 is converted into a digital quantity by an A/D converter 10 and is input to the control device 1. The signal read out by the pickup 5 is also input to the control device 1 via the signal processing device w2.

The control device [1 determines whether reading is being performed by the pickup 5 or not, and if reading is being performed, when transitioning to the stop mode, it applies reverse rotation voltage to the servo device 3 in the same way as in the past. Outputs an instruction signal. In response to this signal, a reverse rotation voltage is applied to the spindle motor 6 via the driver 4, and the rotation speed of the spindle motor 6 gradually decreases. The control device [1 detects the period of the readout signal from the pickup 5, and when it detects that the period is longer than the normal rotation period, it outputs a command to the servo device [3 to stop applying the reverse rotation voltage. . This applies a brake to the spindle motor 6 to stop the disk rotation.

If there is no read signal from the pickup 5, the control device 1 determines the rotation direction of the spindle motor 6 based on the signal from the A/D converter 10 when shifting to the stop mode. That is, if the voltage signal from the A/D converter 10 is a voltage that requires fast forward rotation, it is determined that forward rotation has runaway, and if the voltage signal is a voltage that requires fast reverse rotation, it is determined that reverse rotation has runaway. The spindle motor 6 is configured to apply a brake to the spindle motor 6 by applying a voltage in a rotation direction opposite to the rotation direction for a predetermined period of time.

In addition, at this time, the time for applying the brake voltage may be changed depending on the size of the disk to ensure that the rotation of the disk is stopped.

Figure 2 shows the operation.

When there is a stop command, the control unit W1 determines whether reading is being performed by the pickup 5 (step 20), and if reading is being performed, the control unit W1 determines whether reading is being performed by the pickup 5 or not.
Output an instruction signal for applying a reverse rotation voltage to Step 3 (Step 2
1). Then, the control device 1 detects the period of the read signal from the pickup 5 and checks whether the period has become longer than the normal rotation (step 22). If it has become longer, it applies a reverse rotation voltage to the servo device 3. A stop command is output (step 23), which causes the spindle motor 6 to
The brake is applied and the disc rotation stops.

If there is no read signal from the pickup 5 in step 20, the rotational direction of the spindle motor is detected based on the signal from the A/D converter 10 (step 24). As a result, in the case of forward rotation runaway, the servo device i3 is instructed to apply a reverse rotation voltage (step 25), and in the case of reverse rotation runaway, the servo device 3 is instructed to apply a forward rotation voltage (step 26). Then, the elapse of a predetermined time is checked (step 27), and when the predetermined time has elapsed, the process jumps to step 23.

This makes it possible to reliably stop the rotation of the disk even when there is no disk read signal from the pickup 5.

As explained above, in the above embodiment, even when there is no read signal from the pickup 5, it is possible to reliably stop the disk.

<Effects of the Invention> As explained above, the disk reproducing apparatus of the present invention includes a means for detecting whether or not a signal is being read from the disk, a means for A/D converting the voltage applied to the spindle motor, and a means for detecting whether or not a signal is being read from the disk. When the signal of A/
It detects the rotational direction based on the signal from the D-converting means, and applies a voltage in the opposite direction to the rotational direction to the spindle motor based on the detection result. Even when reading is not possible, it is possible to reliably apply the brake to the spindle motor and stop its rotation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flowchart for explaining its operation. 1: Control device, 2: Signal processing device, 3: Servo device, 4
: Driver, 5: Pickup, 6: Spindle motor, 7: D/A converter, 8: Amplifier, 9: Speaker, 10: A/D converter.

Claims (1)

[Scope of Claims] Means for detecting whether a signal from the disk is being read; means for A/D converting the voltage applied to the spindle motor; and A/D converting when the signal from the disk is not being read.
A disc playback device comprising: means for detecting a rotational direction based on a signal from a converting means, and applying a voltage in a rotational direction opposite to the rotational direction to a spindle motor based on the detection result. .