JP2001070880A - Maltifunctional vibration actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multifunctional vibration actuator which minimizes the influence of the production variations of the minimum resonance frequency by a vibration actuator and a casing and the variations by a temperature change or change with lapse of time, or the like, and renders stable mechanical vibrations at a low cost with a less space and lower electric power consumption. SOLUTION: After the resonance frequency of the vibration actuator 101 is detected, its drive frequency is selected from fixed three frequencies and the actuator is driven. The vibration actuator 101 is otherwise driven while the drive frequency is regulated to the resonance frequency of the actuator. Further, the vibration actuator 101 is driven while the drive frequency is iteratively swept in a specified range inclusive of the resonance frequency of the vibration actuator 101.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical vibration generator for a device having a method of transmitting a signal with mechanical vibration, and more particularly to a portable telephone, a PDA, and the like.
(Personal Digital Assistants) The present invention relates to a multifunctional vibration actuator for a portable terminal, a toy, and the like, and a drive circuit thereof.

[0002]

2. Description of the Related Art Conventionally, in a cellular phone or the like, a method of rotating a motor inside the cellular phone has been generally used to realize mechanical vibration for transmitting an incoming call regardless of a ringing tone. However, mounting the motor inside the housing of the mobile phone has increased the size of the housing of the mobile phone. In addition, the life of the battery is shortened because the battery is used and the motor is rotated.

In place of such a method of rotating a motor, a speaker (vibration actuator) having a vibration function, that is, a signal transmission function by mechanical vibration, is becoming mainstream. According to this method, it is possible to reduce not only the power consumption but also the number of mounted components. As a method of driving the speaker with the vibration function, the lowest resonance frequency (100 to 200 Hz) of the speaker (vibration actuator) itself is used.
There is a method of driving the housing itself that supports the speaker.

[0004]

However, the lowest resonance frequency of the speaker (vibration actuator) often fluctuates around 10 Hz from the center frequency for the following reasons. That is, (1) the manufacturing variation of the vibration actuator itself, (2) the variation due to the temperature change of the vibration actuator itself, (3) the variation due to the temporal change of the vibration actuator itself, and (4) the variation due to the housing itself when attached to the housing. Variation, (5) variation due to temperature change of the casing when attached to the casing, (6) variation due to temporal change of the casing when attached to the casing, (7) variation when attached to a different casing. It is. Due to these variations, there is a problem that stable mechanical vibration cannot be obtained.

Therefore, in the present invention, the influence of the manufacturing variation of the minimum resonance frequency due to the vibration actuator and the housing, the variation due to temperature change, aging change, and the like is minimized, and low cost, space saving, low power consumption and stable. It is an object of the present invention to provide a multi-functional vibration actuator that provides a mechanical vibration.

[0006]

According to the present invention, in order to solve the above-mentioned problems, first, second and third oscillating circuits which oscillate at three different fixed frequencies are provided. A switching circuit that switches and operates the oscillation circuit of No. 3, a frequency detection circuit that detects a resonance frequency of the vibration actuator, and a frequency setting circuit that controls the switch circuit according to the frequency detected by the frequency detection circuit. Further, a three-point frequency supply with a frequency detection function comprising an amplifier using a positive-phase amplifier and a negative-phase amplifier, which amplifies the output of an oscillator selected from the first to third oscillators and supplies the amplified output to a vibration actuator. The vibration actuator is driven by the circuit.

Further, according to the present invention, a frequency detection circuit for detecting a resonance frequency of a vibration actuator, a frequency-to-voltage conversion circuit for converting a frequency detected by the frequency detection circuit to a voltage, and a frequency-to-voltage conversion circuit A voltage-controlled oscillation circuit that changes the oscillation frequency in accordance with the obtained voltage value; and an amplifier including a positive-phase amplifier and a negative-phase amplifier that amplifies the output of the voltage-controlled oscillation circuit and supplies the output to the vibration actuator. The driving frequency can be adjusted to the resonance frequency of the vibration actuator by the driving circuit to drive the vibration actuator.

Further, according to the present invention, a triangular wave or
It consists of a sawtooth wave oscillation circuit, a voltage controlled oscillation circuit that changes the oscillation frequency according to the voltage, and an amplifier with a positive-phase amplifier and a negative-phase amplifier, and continuously extends a certain frequency range including the resonance frequency of the vibration actuator. It is also possible to drive the vibration actuator while sweeping repeatedly.

[0009]

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

FIG. 1 shows a driving method of a vibration actuator according to an embodiment of the present invention. The operation principle is as follows. First, an electromotive force is applied to the vibration actuator 101 to obtain a vibration resonance point. This resonance frequency is input to the frequency detection circuit 102, and the resonance frequency is detected. A certain frequency is output from the frequency setting circuit 103 based on the frequency obtained from this. The set frequency is amplified by the amplifier 108 and input to the vibration actuator 101. By this work, the vibration actuator 101 → frequency detection circuit 102 → frequency setting circuit 10
3 → the amplifier 108 → the vibration actuator 101 draws a closed loop, and oscillates autonomously. With the above configuration, when a closed loop is drawn, the closed loop is turned off by the switch circuit 104. Then, according to a command from the frequency setting circuit 103, the first oscillation circuit 105, the second oscillation circuit 106, or the third oscillation circuit 106 closest to the current resonance point frequency.
Turn on one of the oscillator circuits. One of the three oscillation circuits is set to the standard resonance frequency of the vibration actuator 101, one to the standard frequency minus 5 Hz, and one to the standard frequency plus 5 Hz. This frequency is amplified by an amplifier 108 composed of a positive-phase amplifier and a negative-phase amplifier, and input to the vibration actuator 101. As a result, the vibration actuator is driven at a frequency substantially equal to its own resonance frequency. With this method, it is possible to select a frequency oscillation circuit that is closest to the resonance frequency and is stable. Since the state of the oscillation circuit is constantly changing and the temperature characteristics and the like are very delicate, a stable output can be obtained if the oscillation frequency is fixed.

Next, a driving method of a vibration actuator according to another embodiment will be described with reference to FIGS. First, an electromotive force is applied to the vibration actuator 201 to obtain a vibration resonance point. The resonance frequency at this time is detected by the frequency detection circuit 202. Then, this frequency is converted into a voltage by the frequency-voltage conversion circuit 203.
At this time, as shown in FIG. 4, the converted voltage is set in a range of 2 V between 0.5 and 2.5 V in consideration of the allowable voltage of the portable device battery and the voltage loss of the conversion circuit. Next, by inputting a prescribed voltage value, the frequency generated by the voltage control oscillation circuit 204 set in advance is set to a positive-phase amplifier and a negative-phase amplifier so that a desired resonance frequency of the vibration actuator 201 can be obtained. , And input to the vibration actuator 201. Thus, the vibration actuator 201 can be vibrated at a desired resonance frequency. Since this method is a closed loop, it is possible to always convert information obtained from the vibration actuator to an optimum frequency and drive or vibrate the vibration actuator.

Referring to FIGS. 3, 5, and 6, a driving method of a vibration actuator according to still another embodiment will be described. The operation principle is as follows. As described above, the variation in the resonance frequency of the vibration actuator 301 is limited to a certain range. It is also known that the use of a voltage-controlled oscillation circuit makes it possible to output a variable frequency within a certain range. Therefore, if the range of variation in the resonance frequency of each vibration actuator is swept, the drive frequency always passes through the resonance frequency of the vibration actuator 301. Also, by appropriately setting the cycle (time axis) passing through the resonance frequency, the vibration of the vibration actuator felt by the human body can be further increased. The specific circuit operation is as shown in FIG. The cause of the variation in the resonance frequency due to the vibration actuator 301 has been analyzed, and it is possible to grasp the range of the variation in the resonance frequency by an experiment.

A voltage controlled oscillation circuit 303 set in advance to output a frequency within the range of variation of the resonance frequency is prepared. Then, by inputting the output voltage of the triangular wave oscillation circuit 302 oscillating in the range of the control voltage to the voltage control oscillation circuit, a desired range of frequency can be obtained on a desired range of time axis. By using this method, it is possible to supply a frequency corresponding to measurement data from a vibration medium (vibration actuator and housing) obtained in advance to the vibration actuator.

Next, the operation of the specific circuit shown in FIG. 5 will be described in detail. As an operation principle, first, a triangular wave output circuit for generating a reference signal using a time constant of a capacitor is configured. This triangular waveform output circuit includes a triangular wave oscillation circuit and a voltage controlled oscillation circuit. The time constant is adjusted so that the time axis forming the triangular waveform is about 1 sec. Next, a triangular waveform having a time axis of about 1 sec is applied to a time constant of about 7 msec.
The signal is input to a triangular waveform output circuit for generating an output signal set to c (about 140 Hz). With such an input form, a desired sweep signal can be obtained in a frequency range around 140 Hz.

FIG. 6 shows the frequency spectrum of the output waveform.
Shown in Energy is dispersed around 140Hz,
It can be seen that the output frequency is swept in this band.

By the way, the time axis of the frequency sweep is set to about 1
The reason for setting to sec is that it is experimentally known in advance that the time interval is such that the human body can greatly sense the vibration. Also, there is no particular limitation on the shape of the triangular wave,
For example, a sawtooth waveform may be used, and a waveform that can be efficiently generated is preferable.

[0017]

As described above, according to the present invention,
Multi-function vibration actuator that minimizes the effects of manufacturing fluctuations of the lowest resonance frequency due to the vibration actuator and the housing, temperature fluctuations, aging, etc., and provides stable mechanical vibration at low cost, space saving, low power consumption Can be provided.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a principle configuration of a driving method of a vibration actuator according to an embodiment of the present invention.

FIG. 2 is a circuit block diagram showing a principle configuration of a driving method of a vibration actuator according to another embodiment of the present invention.

FIG. 3 is a circuit block diagram showing a principle configuration of a driving method of a vibration actuator according to still another embodiment of the present invention.

FIG. 4 is a diagram showing a voltage used for a voltage-controlled oscillation circuit.

FIG. 5 is a configuration diagram of a frequency sweep circuit using a triangular wave oscillation circuit and a voltage controlled oscillation circuit.

6 is an output spectrum diagram of the frequency sweep circuit shown in FIG.

[Explanation of symbols]

 Reference Signs List 101 vibration actuator 102 frequency detection circuit 103 frequency setting circuit 104 switch circuit 105 first oscillation circuit 106 second oscillation circuit 107 third oscillation circuit 108 amplifier 201 vibration actuator 202 frequency detection circuit 203 frequency voltage conversion circuit 204 voltage controlled oscillation Circuit 205 Amplifier 301 Vibration actuator 302 Triangular wave oscillation circuit 303 Voltage controlled oscillation circuit 304 Amplifier R6 to R13 Resistors C2, C3 Capacitors V1, V2 Voltage terminals

Claims (4)

[Claims] 1. A driving circuit for a vibration actuator that transmits a signal not only by a voice vibration but also by a mechanical vibration, wherein the first, second, and third vibration circuits oscillate at three different fixed frequencies. An oscillation circuit, a switch circuit that selectively switches and operates the first to third oscillation circuits, a frequency detection circuit that detects a resonance frequency of the vibration actuator, and a frequency detection circuit that detects a resonance frequency of the vibration actuator. A frequency setting circuit for controlling the switch circuit, and a positive-phase amplifier and a negative-phase amplifier for amplifying an output of an oscillator selected from the first to third oscillators and supplying the amplified output to the vibration actuator. A driving circuit for a vibration actuator, which is a three-point frequency supply circuit with a frequency detection function comprising an amplifier. 2. A driving circuit for a vibration actuator which transmits a signal not only by voice vibration but also by mechanical vibration, comprising: a frequency detection circuit detecting a resonance frequency of the vibration actuator; and a frequency detection circuit detecting the resonance frequency of the vibration actuator. A frequency-to-voltage conversion circuit that converts the converted frequency to a voltage,
A voltage-controlled oscillation circuit that changes the oscillation frequency according to the voltage obtained by the frequency-voltage conversion circuit, and further amplifies the output of the voltage-controlled oscillation circuit and supplies the output to the vibration actuator; A driving circuit for a vibration actuator, comprising: an amplifier using an amplifier. 3. A driving circuit for a vibration actuator which transmits signals not only by voice vibration but also by mechanical vibration, comprising: a triangular wave or sawtooth wave oscillation circuit;
It is composed of a voltage-controlled oscillation circuit that changes the oscillation frequency according to the voltage, and an amplifier with a positive-phase amplifier and a negative-phase amplifier, and continuously repeats a certain frequency range including the resonance frequency of the vibration actuator to sweep. A driving circuit for a vibration actuator, wherein the driving circuit is driven while being driven. 4. A multifunctional vibration actuator, wherein the vibration actuator is driven by the drive circuit for a vibration actuator according to claim 1. Description: