JPS59165273A - Controller with brush motor of disc record player - Google Patents

Abstract

PURPOSE:To eliminate harsh noise due to a pulse voltage and to attain sure rotating speed control by providing the pulse voltage only when an insulating film is produced and the rotation of a brush motor is stopped so as to destruct said insulating film. CONSTITUTION:When the brush motor 23 for carrying optical pickup is driven, the output terminal of a comparator 28 goes to an L level, a switching circuit 30 is turned off and a tracking error signal is applied to a motor 23 via an amplifier circuit 22. When the insulating film is produced between the brushes and a rotor and the rotation is stopped, a motor stop detector 29 detects the stop state, supplies a stop detecting signal to the comparator 28, whose output terminal is brought into an H level, thereby turning on the circuit 30 so as to apply the pulse voltage to an adder 25 from a pulse generator 24, the tracking error signal added with the pulse voltage is applied to the motor 23 via the amplifier circuit 22 so as to destroy the insulating film. When the motor 23 is driven again, the output terminal of the comparator 28 is brought into the L level so as to turn off the switching circuit 30.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention is applicable to, for example, a CD (optical compact disc).
The present invention relates to DAD (digital audio disc) disc record players, and particularly to improvements to brush motor control devices thereof.

[Technical background of the invention and its problems]

Recently, in audio equipment, for the purpose of high-fidelity, high-density recording and reproduction of information signals such as audio signals and image signals, digitally encoded signals are converted into i PCM (Halse code modulation). An optical disc record player has been developed in which the calyx is directly recorded on a disc, and during playback, a digitally encoded signal is extracted from the disc and demodulated using an optical pickup. In other words, in this type of device, a digitally encoded signal obtained by converting an information signal into PCM is directly recorded on one side of the disk as uneven bit string buttons with different on/off and intervals. A light beam is emitted from an optical pickup. Then, this light beam hits the bit string, is reflected, and is received by the optical pickup. For this reason, this optical pickup detects the intensity and temporal length of light and outputs a ventilation signal in accordance with this, from which the digitally encoded signal recorded on the disk is read out.

By the way, what is particularly important in the above-mentioned optical disc record player is the tracking system and tracking system that allows the light beam to accurately trace the bit string without deviation from the bit string in order to clearly read out the digitally encoded signal. The objective is to reliably control the optical pickup by applying a focus servo to ensure that the focus of the light beam is always on the disk.

FIG. 1 shows the tracking servo system of the optical pickup. That is, numeral 11 in the figure is a disk, and a focusing lens control section 12 is provided below the disk. This focusing lens control section 2 works together with a focusing lens 13 and a magnet (not shown) to move the focusing lens to an arrow mark in the figure.
A) Moving coil 1 for moving in the (B) direction
4th place is better. Then, the focusing lens 13
A light beam emitted from a laser emitter 15 is irradiated via a beam splitter 16 . Therefore, the light beam is focused on the surface of the disk 11 by the focusing lens 13, changes depending on the presence or absence of pits on the disk 11, and is reflected, and travels backward through the focusing lens 13 to the beam spot. 16, the light is reflected by one corner and is received by a photodetector 17.

Here, the upper photodetector 17 is of a so-called 4-division type, and includes four light-receiving areas made up of, for example, photodiodes. Four signals outputted corresponding to the amount of light received by the four light receiving areas of the photodetector 170 are supplied to the tracking error signal generation circuit 18. This tracking signal generation circuit 18 has an IJx circuit configuration.
By adding and subtracting the four signals output from the photodetector 17, the focus of the light beam relative to the bit string on the disk 1 is shifted (tracking error).
The system generates and outputs a tracking error signal corresponding to the following.

The l.racking error signal outputted from the tracking error signal generation circuit 18 is transmitted to the phase compensation circuit 19.
and an amplifier circuit 20f: the moving coil 14 via
The focusing lens 13 is controlled so that the tracking error is corrected.

On the other hand, the tracking error signal outputted from the amplifier circuit 20 is supplied to a brushed motor 23 for feeding the optical big amplifier via a low-frequency wave generator 21 and an amplifier circuit 22.

It is known that when the brushed motor 23 is used for a long period of time, a graphite-like insulating film is formed due to sparks between the brushes and the rotor (comidata) with which the brushes come into contact. I'm here. This insulating coating is particularly likely to occur when the brushed motor 23 is driven to rotate at a very low speed, or is easily destroyed by applying a voltage higher than a certain level to the brushed motor 23. It's something you get.

However, when the supply pressure of the brushed motor 23 is increased, the track direction of the optical pickup (
If the moving speed of the disk 11 (in the radial direction) becomes faster, there is a risk that the tracking servo may become erroneous. For this reason, it is necessary to lower the supply voltage of the first brushed motor 23 to keep the moving speed of the optical pickup to an extremely low speed.

As a result, the brushed motor 23 adds the pulse signal from the pulse generation finger 24 to the tracking error signal from the low-pass filter 21 using the adder 25, and the brushed motor 23 responds. The control signal was configured to be supplied via the amplifier circuit 23 with a pulse voltage that could destroy the insulation coating.

However, in the brushed motor control device configured as described above, since a pulse voltage is constantly applied to the brushed motor 23, unnecessary noise is generated due to the /e russian pressure. Since it has some problems, its improvement will be rejected.

[Purpose of the invention]

This invention has been made in view of the above circumstances, and has a simple configuration that is not affected by the insulating coating, and provides stable rotation of a brushed motor in a low voltage range so as to ensure reliable control of an optical pickup. An object of the present invention is to provide an extremely good brushed motor control device for a disc record player that performs speed control.

[Summary of the invention]

That is, the present invention reads and suspends the digitized data from a disk recorded with digitized data obtained by converting information signals into PCM through an optical pickup that is moved in the radial direction of the disk, and also outputs a tracking error signal. and generate this tracking error signal f)
In a brushed motor control device for a disc record player, which controls the rotational direction and rotational speed wave of a brushed motor for fully moving the optical pickup, a stop state of the brushed motor is detected and a stop detection signal is output. and a first means for controlling the voltage level of the brush motor to be formed between the brushes of the motor and the rotor with which the brushes are in contact in response to the stop detection signal from the first means. The present invention is characterized by comprising a second means for switching to a voltage level sufficient to break the insulating coating.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 shows the main parts of an optical disc record player to which the present invention is applied. In the figure, the same parts as in FIG.

That is, the amplifier circuit 20 supplies the tracking error signal to the moving coil 14 as described above.
The output terminal of the moving coil 14 is commonly connected to each input terminal of the first and second low-frequency di wavers 26 and 27. Among these, the output terminal of the first low-pass filter 26 is connected to one input terminal of the adder 25.

On the other hand, the second low-pass filter 27 has its output terminal connected to one input terminal of the comparator 28.

The other input terminal of the comparator 28 is connected to the output terminal of the motor stop detector 29, and the output terminal thereof is connected to the control input terminal of the switching circuit 300. This switching circuit 30 has a movable terminal connected to the output end of a Norse generator 24 that generates a pulse signal of a predetermined frequency, and a fixed terminal connected to the other input of the adder 25, W,
connected to l. Therefore, the output of this adder 25 is:
is connected via an amplifier circuit 22 to a brush motor 23 for feeding the optical pickup.

Here, the motor stop detector 29 is configured to detect the stopped state of the brush motor 23 using a signal obtained by integrating the voltage that drives the moving coil 14, for example.

Further, when the control input terminal of the switching circuit 30 is at a low level (hereinafter referred to as L level), the switching circuit 30 is in an off state (4), and the control input terminal is at a high level (hereinafter referred to as H level).
When the voltage is on (referred to as level), it is turned on and a pulse voltage is supplied to the adder 25.

That is, in the 1ζ brushy/4 brush motor control device configured as described above, when the brushy motor 23 is being rotated without an insulating film formed, the comparator 28
Since the output terminal of the switching circuit 30 is set to the L level, the switching circuit 30 is turned off. For this reason, the brushed motor 23 is driven to rotate at a very low speed by being supplied with a low voltage range tracking signal from the pulse generator 24 to which the i4 pulse voltage is not added via the amplifier circuit 22fr.

When the brushed motor 23 stops rotating due to the formation of an insulating coating, the motor stop detector 29 detects the stop as described above. At this time, the motor stop detector 29 supplies its stop detection signal to the comparator 28, and sets the output terminal of the comparator 28 to H level. Therefore, the switching circuit 30 is turned on and supplies a pulse voltage from the pulse generator 24 to the adder 25. As a result, the brushed motor 23 is supplied with a tracking error signal to which the adder 25 adds a pulse voltage sufficient to destroy the insulating film through the amplifier circuit 23, thereby destroying the insulating film.

At this time, the brushed motor 23 is rotated again, so that the output terminal of the comparator 28 reaches the iKL level, thereby turning off the switching circuit 30. For this reason, the brushed motor 23 is again in the low I\ pressure region where the NOP pulse voltage generated by the pulse generator 24 is not added, and the tracking error occurs in the amplifier circuit 23.
It is supplied through the motor and rotated at an extremely low speed.

Here, the above-mentioned pulse voltage +dJ is 1% when there is no problem with the rotation of the brushy motor 23 (1), j is the value of the blade V1.

In this way, when the brushed motor 23 is rotated with a measurement, Q and (pulse voltages are not applied in the driving state, S and Δ edge distortion occurs and its rotation stops, and only in the ζ state. A voltage is applied to destroy the insulating film, and the brushed motor 23 is always
It is configured to maintain all the rotation at ultra-low speeds. For this reason,
The brushed motor 23 does not generate any noise due to the pulse voltage under normal rotational driving conditions.

In addition, with the above configuration, the brushed motor 23 can be operated using its rotary seat 1til+f: low foot pressure area, so reliable rotational speed control is achieved, and the pickup truck skips, etc. This can be prevented.

Here, without being limited to the above embodiment, the brushed motor 2
For example, as shown in FIG. 3, the motor stop detection means for detecting rotation stop of No. 3 detects the rotation speed of the brushed motor 23 using bridge resistors R1, R2, and R3, and detects the rotation speed of the brushed motor 23 using the output signal and the timer 31. It is equally effective to configure the rotation stoppage to be detected by taking the difference from the set time.

It goes without saying that the present invention is not limited to the above embodiments, and that various modifications can be made without departing from the gist of the invention.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to control the rotational speed of a brushed motor stably in a low voltage region without being affected by an insulating coating and with a simple configuration, and to ensure reliable control of an optical pickup. It is possible to provide an extremely good brushed motor control device for a 7" and 7" record player.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional brushed motor control device for a disc record player, FIG. 2 is a block diagram showing a brushed motor control device for a disc record player according to an embodiment of the present invention, and FIG. FIG. 7 is a circuit diagram showing another embodiment of the motor stop detector. 11...Disk, 12...Focusing lens lightning lj1'
a11 part, 13...Focusing lens part, 14...Moving coil, 15...Laser emitter, 16...Beam sinter, 17...-Photodetector, 18...
- Tracking error signal generation circuit, 19... Phase compensation circuit, 20... Amplification circuit, 22... Amplification circuit, 23
...Brushed motor, 24...Pulse generator, 2
5... Adder, 26... First filter, 22...2
≧! No. 2 wave generator, 28... Comparator, 29... Motor stop detection signal, 30... Switching circuit, 31...
・Timer, R1, R2' +R3...Resistance.

Claims (1)

[Claims] The digitized data is read out through an optical pickup that is moved in the radial direction of the disk on which the digitized data obtained by converting the information signal into PCM is recorded, and a tracking error signal is generated to detect the tracking error. In a brushed motor control device for a disc record player, which controls the rotational direction and rotational speed of a brushed motor that moves the optical pickup according to a signal, a stoppage detection method is provided by detecting a stopped state of the brushed motor. The first output signal
means, and in response to a stop detection signal from the first means, the voltage level of the brushed motor is changed to destroy an insulating coating formed between the brushes of the motor and the rotor with which the brushes are in contact. Switch to a voltage level sufficient for the second
A brushed motor control device for a disc record player, characterized in that the brushed motor control device comprises the following means.