JPH07288991A - Information recorder/reproducer - Google Patents

Abstract

PURPOSE:To reduce unnecessary radiation and noise caused by the switching noise of a motor. CONSTITUTION:A signal reproduced from an optical disc 1 through a head 2 is delivered through a head amplifier 3 to a signal processing circuit 4 where an information signal containing address information is reproduced. The information signal is delivered to an address separation circuit 5 where the address information is separated. The address information is delivered to a target speed setting ROM 6 and then the inclination of a trapezoidal drive signal for a motor 10 is determined at a phase conduction circuit 7. The phase conduction circuit 7 detects a voltage generated from the motor 10 through a counter electromotive force detecting circuit 9 thus controlling the phase switching timing of the phase conduction circuit 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording and reproducing information such as music signals and image signals on a disc-shaped information recording carrier, particularly an optical disc.

[0002]

2. Description of the Related Art In recent years, in information recording / reproducing apparatus, there is a remarkable tendency to record a large amount of data on a medium such as high density recording. In this field, a lot of research announcements on high density recording have been made. However, high-density recording is still in the research stage, and it is easier to compress the amount of data from the viewpoint of practicality of industrialization, and in terms of voice recording, in combination with the development of effective compression algorithms in recent years, Has been commercialized.

For example, a so-called "mini disc" (hereinafter abbreviated as MD) or "digital compact disc"
"Cassette". Among them, the MD is smaller and lighter than an uncompressed so-called "compact disc" (hereinafter, abbreviated as CD), and is easier to carry than a conventional CD player.

In such an MD player, it is important to reduce the thickness, and a coreless motor or the like is usually used for the disk rotation drive section. However, the coreless motor has a problem that it has a short life because it has a brush. For this reason, recently, attempts have been made to use a brushless motor that is sensorless. As a drive system for such a sensorless brushless motor, there is, for example, the invention disclosed in Japanese Patent Laid-Open No. 4-359693.

[0005]

However, in the conventional sensorless brushless motor driving method as described above, in the case of a three-phase motor, square waves with a phase difference of 120 degrees are used as driving signals. However, there is a problem in that it causes unnecessary radiation and motor noise due to switching noise.

An object of the present invention is to solve the above-mentioned conventional problems, and an object thereof is to provide an information recording / reproducing apparatus capable of reducing unnecessary radiation and noise due to motor switching noise.

[0007]

In order to achieve this object, an information recording / reproducing apparatus of the present invention comprises a reproducing head for reproducing a signal from a disc-shaped information recording carrier on which address information is recorded in advance, and this disc-shaped information. A motor having a plurality of phases for rotating the record carrier, driving means for driving the motor, phase passing means for determining the timing of phase switching in the driving means, and address information separated from the output of the reproducing head. And a changing means for changing the phase passing timing of the phase passing means according to the output of the address separating means.

Further, the changing means changes the inclination in the drive signal of each phase outputted by the driving means according to the address information outputted by the address separating means.

A motor having a plurality of phases for rotating a disc-shaped information record carrier in which address information of a constant period is recorded on concentric or spiral information tracks,
Drive means for driving the motor, phase passing means for determining the timing of phase switching in the drive means, setting means for setting a target address to be searched from outside the device,
And changing means for changing the phase-communication timing of the phase-communication means according to the output of the setting means.

Further, the changing means changes the inclination in the drive signal of each phase output from the drive means according to the address information received by the setting means.

[0011]

The information recording / reproducing apparatus of the present invention has the above-mentioned structure.
By utilizing the fact that the target speed is determined 1: 1 by the address information, the slope of the drive signal for generating the trapezoidal wave with no pause section at the target speed is determined, thereby reducing the switching noise. And reduction of noise due to motor vibration.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a first embodiment of an information recording / reproducing apparatus of the present invention. An optical disk 1 which is a disk-shaped information recording carrier has concentric circular or spiral information tracks with a constant period. The address information is recorded, is rotationally driven by the three-phase motor 10, is recordable / reproducible, and is recorded / reproduced by the recording / reproducing head 2. This recording / reproducing operation is directly controlled by the head amplifier 3. In addition, the MD has a magnetic head (not shown), and at the time of recording, the magnetic field generated by the magnetic head is heated to the Curie point of the base material of the optical disc 1 by the infrared laser light output from the recording / reproducing head 2. Is modulated by the recorded signal and recorded.

The output from the head amplifier 3 is sent to the signal processing circuit 4 to reproduce an ADIP (Address In Pregroove) signal which is address information included in the tracking error signal. The address separation circuit 5 receives the ADIP signal, extracts address information, and changes means, that is, a speed target setting ROM which is a memory circuit dedicated to reading the speed target setting value.
Numerical data D corresponding to the phase switching cycle Ta of the motor 10 is output from a table stored in (hereinafter abbreviated as ROM) 6. The numerical data D is sent to the phase passing circuit 7 which is a phase passing means.

The table of the ROM 6 can be easily created by the following procedure.

When the track pitch is p, the recording / reproducing linear velocity is v ₁ , the frequency at which the address changes is f _ck , and the radius of the innermost circumference of the disk-shaped optical disc 1 is r ₀ , the radius r is The following relationship is established between the absolute addresses A.

[0017]

[Equation 1]

The following relationship holds between the rotational angular velocity ω and the radius r.

[0019]

[Equation 2]

From the above two equations, the absolute address (AD
IP) A and the recording / reproducing rotation angular velocity ω can be easily obtained. FIG. 2 shows the relationship between the absolute address A and the rotational angular velocity ω,
An example in which actual numerical values in MD are applied will be shown. These two equations can be solved algebraically, but in order to realize with a microprocessor or the like, the solution shown in FIG.
It is prepared on the table of the ROM 6 and searched.

Next, the operation of the phase-pass processing circuit 7 will be described with a focus on the startup.

3 and 4 are flow charts relating to the operation at the time of starting the phase passing circuit 7 in this embodiment. In FIG. 3, T is the internal value of the counter for measuring the phase passing period,
Td is an internal value of a counter for generating a window for detecting the back electromotive force, Mc is a number indicating the phase passing mode, and Md is a number indicating the mode of the detection window. Here, the phase-communication mode Mc and the detection window Md are set in the motor 10 as shown in FIGS.
The electrical angle is switched every 60 degrees, and the phases are shifted by 1/2 cycle.

The phase passing circuit 7 performs trapezoidal wave drive as shown in FIG. 5 (b). The slope S ₀ of this trapezoidal wave is fixed during startup and is proportional to the numerical data D derived from FIG. By performing such trapezoidal wave drive, changes in the drive current signals i ₁ , i ₂ , and i ₃ near the zero cross become gradual, and mechanical fixation due to electrical unwanted radiation and abrupt electromagnetic field changes. Vibration of the child (coil) can be prevented in advance.

Such three-phase drive current signals i ₁ , i ₂ ,
i ₃ is power-amplified by the power amplifier circuit 8 of FIG. 1, which is a driving means, and supplied to the motor 10. At the same time, the back electromotive force detection circuit 9 detects the generated voltage generated in the three-phase coils as the motor 10 rotates. The detected waves have the waveforms e ₁ , e ₂ and e ₃ as shown in FIG. In FIG. 5A, the shaded areas in the voltage signals e ₁ , e ₂ , e ₃ represent the voltage drop due to the coil resistance of the drive current signals i ₁ , i ₂ , i ₃ .

The acceleration processing detects that the zero cross of the voltage waveforms e ₁ , e ₂ , e ₃ shown in FIG. 5 (a) has entered the detection window, and shortens the phase-communication period Ta to a predetermined value. Can be achieved by doing. For example, when Md = 6 in FIG. 5A, if the power generation voltage e ₂ rises in the detection window, the cycle Ta is shortened. In the flowchart shown in FIG. 3, such a detection window Md is 1/1 in a certain phase mode Mc.
After 2 cycles have elapsed, interrupt is set and next phase mode Mc
This can be easily achieved by disabling interrupts at. When a desired back electromotive force edge is input while the detection window Md is open, the processing shown in FIG. 4 is performed.

Although the operation at the time of start-up has been described above, this embodiment is also effective at the time of steady rotation. For example, constant speed rotation can be obtained if the phase-communication cycle Ta is not shortened in the interrupt process. Further, in the deceleration processing, the ROM table may be reversely drawn from the current rotational speed up to the desired rotational speed.

In this embodiment, ADI is used as the address information.
The case of using the P signal has been described, but only during reproduction, the EFM (Eig) which is the recording and reproduction format of MD.
The same effect can be obtained by using the address information included in the sub code in the (htto Fourteen Modulation) signal.

As described above, according to the first embodiment, since the desired starting rotational speed is calculated in advance from the target address, the slope S ₀ of the trapezoidal wave drive can be made as gentle as possible. Therefore, it is possible to prevent mechanical vibrations of the stator (coil) due to unnecessary radiation due to electrical switching and rapid changes in the electromagnetic field.

FIG. 6 is a block diagram showing the configuration of the second embodiment of the information recording / reproducing apparatus of the present invention. The optical disc 1, the speed target setting ROM 6, the phase processing circuit 7, the power amplification circuit 8, the back electromotive force detection. The circuit 9 and the motor 10 are the same as the corresponding members in FIG. 1 of the first embodiment, so the same reference numerals are given and detailed description thereof is omitted.

In FIG. 6, a default value (a value corresponding to the innermost rotation speed) is set in the address conversion table 11 stored in the ROM 6 at startup. According to this value, the start-up process as described above is performed by the phase-pass processing circuit 7, the power amplification circuit 8 and the counter electromotive force detection circuit 9, and the TOC (Table Of Content) recorded on the innermost circumference of the optical disc 1 is performed.
read s). After that, the address corresponding to the track number (corresponding to the song number) N of all the music information recorded on the optical disc 1 is created and stored in the address conversion table 11.

The key matrix 12, which is the setting means,
It is used to enter the desired track number N ₀ into the device as desired by the operator. This input track number N
₀ is converted into the address data D in the first embodiment in the address conversion table 11.

This address data D is a speed target setting ROM.
6, the slope S ₀ of the trapezoidal wave drive is determined, and the phase-pass processing circuit 7, the power amplification circuit 8 and the back electromotive force detection circuit 9 are determined.
Then, the same activation as in the first embodiment is performed.

As described above, according to the second embodiment, since the user interface called the key matrix is provided for the first embodiment, it is more convenient and the desired starting rotation speed can be set by the user based on the target address. Since it is designated and started, the slope S ₀ of the trapezoidal wave drive can be set to an optimum gentleness with respect to an arbitrary target track. Therefore, it is possible to more effectively prevent unnecessary radiation accompanying electrical switching and mechanical vibration of the stator (electromagnetic coil) associated with a sudden change in electromagnetic field.

[0034]

As described above, in the information recording / reproducing apparatus of the present invention, according to the invention of claim 1, the phase switching timing in the drive signal of the motor for rotating the disk-shaped information recording carrier is set to the disk. It becomes possible to change it according to the address information from the status information recording carrier so that unnecessary radiation and noise accompanying switching during motor operation do not occur.

According to the invention of claim 3, in any target track set by the setting means,
In the same manner as the described invention, it is possible to suppress the generation of unnecessary radiation and noise accompanying switching during the operation of the motor.

According to the second and fourth aspects of the present invention, an optimum trapezoidal wave drive inclination can be realized according to the starting target rotation speed or the steady drive rotation speed, and low radiation and low noise are possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an information recording / reproducing apparatus of the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the absolute address A and the rotational angular velocity ω in the first embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 4 is a flowchart showing the operation of the first embodiment of the present invention.

FIG. 5 is a waveform chart of a main part of the first embodiment of the present invention.

FIG. 6 is a block diagram showing the configuration of a second embodiment of the information recording / reproducing apparatus of the present invention.

[Explanation of symbols]

1 ... Optical disc (disc-shaped information recording carrier), 2 ... Recording / reproducing head (reproducing head), 3 ... Head amplifier, 4 ... Signal processing circuit, 5 ... Address separation circuit, 6 ... Speed target setting RO
M (change means), 7 ... Phase-pass processing circuit (phase-pass means), 8 ...
Power amplification circuit (driving means), 9 ... Back electromotive force detection circuit,
10 ... Motor, 11 ... Address conversion table, 12 ... Key matrix (setting means)

Claims (4)

[Claims] 1. A reproducing head for reproducing a signal from a disc-shaped information record carrier on which address information is recorded in advance, a motor having a plurality of phases for rotating the disc-shaped information record carrier, and driving this motor. Driving means, phase passing means for determining the timing of phase switching in the driving means, address separating means for separating address information from the output of the reproducing head, and phase passing means for the phase passing means according to the output of the address separating means. An information recording / reproducing apparatus, comprising: changing means for changing the phase-communication timing. 2. The information according to claim 1, wherein the changing unit changes a slope in a drive signal of each phase output by the driving unit according to the address information output by the address separating unit. Recording / playback device. 3. A motor having a plurality of phases for rotating a disk-shaped information record carrier in which address information of a constant period is recorded on concentric or spiral information tracks, and a driving means for driving the motor. Phase passing means for determining the timing of phase switching in the driving means, setting means for setting a target address to be searched from outside the apparatus, and phase passing timing of the phase passing means are changed according to the output of the setting means. An information recording / reproducing apparatus, comprising: 4. The information recording apparatus according to claim 3, wherein the changing unit changes a slope in a drive signal of each phase output from the drive unit according to the address information received by the setting unit. Playback device.