JPH11313396A - Piezoelectric vibrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric vibrator that employs a piezoelectric drive vibration element so as to easily obtain a sufficiently large vibration displacement. SOLUTION: The vibrator is provided with a metallic vibration plate whose one end acts like a fixed end and whose other end acts like a free end with a low frequency vibration weight attached thereto, a piezoelectric drive vibration element 3 placed on a front side of the metallic vibration plate, a vibration piece vibration detection element, a switch means 32 that is operated based on a feedback signal (f) outputted from the vibration piece vibration detection element, a bias oscillation circuit 33 that provides an oscillation output based on the feedback signal (f) and an amplifier means 34, and a drive signal (d) with a prescribed frequency is given to the vibration piece vibration detection element through the switch means 31 that is turned on/off synchronously with the vibration of the vibration piece vibration detection element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrator for calling an incoming call of various communication devices by low frequency vibration, and more particularly to a vibrator using a piezoelectric driving vibration element.

[0002]

2. Description of the Related Art Conventionally, a dilator has mainly connected an electromagnetic motor and an eccentric weight, and operates the eccentric weight by rotation of the motor to generate low-frequency vibration.
Then, the communication device and the entire independent calling device indicate an incoming call with this vibration.

In such a vibrator in which an electromagnetic motor and an eccentric weight are combined, the electromagnetic motor must be operated, and a relatively large current must be supplied to the motor coil. For this reason, the battery consumption of the communication device and the like was extremely large.

Further, since an electromagnetic motor is used as a vibration source, the vibrator itself becomes very large, which is against the miniaturization of communication devices and the like, and is not practical.

Therefore, as a method of reducing power consumption and miniaturization, it is conceivable to use a piezoelectric driving vibration element as a vibration source.

[0006]

However, a vibrator using a piezoelectric driving vibration element as the vibration source has not yet been put to practical use. This is because it is necessary to supply a high-voltage driving signal to the piezoelectric driving vibration element in order to largely displace the low-frequency vibration weight by the piezoelectric driving vibration element. Also, when a deviation occurs between the vibration of the piezoelectric driving vibration element and the natural vibration (actual vibration) of the metal vibrating body (the vibrating piece) including the low-frequency vibrating weight, the vibrations cancel each other, and the vibration displacement becomes extremely large. This is due to the problem of becoming weak.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a piezoelectric vibrating element capable of easily obtaining a sufficiently large vibration displacement, and a metal vibration including a low-frequency vibrating weight. An object of the present invention is to provide a piezoelectric vibrator in which vibration displacement of a piece is not attenuated.

[0008]

According to a first aspect of the present invention, there is provided a plate-shaped metal vibrating piece having one end serving as a fixed end and the other end serving as a free end having a low-frequency vibrating weight attached thereto. A piezoelectric drive vibration element and a vibration piece vibration detection element disposed on the surface, switch means that operates based on a feedback signal output from the vibration piece vibration detection element, and a bias oscillation circuit that oscillates and outputs based on the feedback signal And amplifying means, wherein the oscillation output of the bias oscillation circuit is amplified by the amplifying means, and the switching means, which operates based on the feedback signal, causes the piezoelectric driving vibration to be performed by a driving signal having a predetermined frequency synchronized with the feedback signal. This is a piezoelectric vibrator in which an element is operated.

According to a second aspect of the present invention, there is provided a plate-shaped metal vibrating piece having one end serving as a fixed end and the other end serving as a free end having a low-frequency vibrating weight attached thereto, and a piezoelectric member disposed on the surface of the plate-shaped metal vibrating piece. A driving vibration element and a vibration piece vibration detection element, an oscillation circuit that generates a rectangular wave clock signal based on a feedback signal output from the vibration piece vibration detection element, and adding the rectangular wave clock signal based on the feedback signal And a clock signal adding logic circuit for increasing the wave height. The piezoelectric vibrator operates the piezoelectric driving vibration element using an output of the clock signal adding logic circuit corresponding to the feedback signal as a drive signal.

[0010]

In each of the inventions, a piezoelectric vibrating element for generating vibration in the metal vibrating piece and a vibrating piece vibration detecting element for detecting actual vibration of the metal vibrating piece are arranged on the metal vibrating piece. I have.

In the first invention, the drive signal supplied to the piezoelectric drive vibration element is controlled by the switch element that turns on and off based on the feedback signal from the vibration piece vibration detection element. Therefore, the ON-OFF cycle is
The metal vibrating reed can be made to follow the actually vibrating metal vibrating reed, and the metal vibrating reed can be operated with the most stable large displacement vibration.

[0012] The drive signal has the oscillation output of the bias oscillation circuit raised in potential by the amplifying means. For this reason, a signal necessary to generate a sufficiently large vibration in the piezoelectric driving vibration element can be obtained.

According to a second aspect of the present invention, an oscillating circuit generates an amplified rectangular wave clock signal based on a feedback signal of the resonator element vibration detecting element, and generates the clock signal based on the feedback signal. The addition is performed by the addition logic circuit to obtain drive vibration to be supplied to the piezoelectric drive vibration element.
That is, the drive signal is a rectangular wave having a high wave height at a cycle corresponding to the actual vibration of the metal vibrating reed and can be directly generated.

By using the piezoelectric vibration driving element as the vibration source of the DC-DC converter circuit and the vibrator as described above, the miniaturization can be easily achieved as compared with the prior art, and the actual size of the metal vibrating piece can be improved. Vibration can be generated in the piezoelectric driving vibration element following the above vibration, and the vibration of the metal vibrating piece is not attenuated. In addition, a high-potential drive signal can be easily generated and generated.

Therefore, a sufficiently large vibration displacement can be easily obtained by using the piezoelectric driving vibration element. In addition, the natural vibration of the vibrating piece including the low frequency vibration weight and the piezoelectric driving vibration element is made the same, and the vibration displacement is reduced. The piezoelectric vibrator does not decrease.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A piezoelectric vibrator according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a piezoelectric vibrator, and FIG. 2 is a plan view of a metal vibrating piece of the piezoelectric vibrator.

The piezoelectric vibrator includes a plate-shaped metal vibrating reed 1,
It comprises a low-frequency vibrating weight 2, a piezoelectric vibration driving element 3, and a piezoelectric vibration extracting element 4.

The plate-shaped metal vibrating piece 31 is made of a predetermined elastic metal member such as phosphor bronze, 42 alloy, Kovar, and has a length of 18.0 to 22.0 mm and a maximum width of 3.0.
mm, minimum width of constricted part 2.0 mm, thickness about 0.3 m
m is a metal plate-shaped piece.

The other end of the plate-shaped metal vibrating piece 1 is a free end, and a low-frequency vibrating weight 2 is integrally attached to the tip.

A housing-like container 5 made of resin or the like
, The fixed end of the metal vibrating reed 1 is fixed, and the low-frequency vibrating weight 2, which is a free end, extends outside the container 5 and relatively vibrates.

The low-frequency vibrating weight 2 is made of, for example, tungsten metal and has a rectangular parallelepiped shape of 3 mm × 3 mm × 4 mm. The low-frequency vibrating weight 2 is, for example, 0.1 mm.
It weighs 9 to 1.6 g.

The piezoelectric vibrating element 3 and the vibrating piece vibration detecting element 4 are adhered to one main surface of the metal vibrating piece 1, respectively.

The piezoelectric vibration driving element 3 and the vibrating piece vibration detecting element 4 are substantially piezoelectric elements, and are made of a piezoelectric ceramic substrate, such as PZT (lead zirconate titanate), which has been subjected to polarization processing and electrodes on both main surfaces. It is composed of

The above-described piezoelectric drive vibration element 3 vibrates in response to a drive signal of a predetermined alternating voltage, and this vibration affects the plate-shaped metal vibrating piece 31 and causes the plate-shaped metal vibrating piece 1 to vibrate.
At a predetermined frequency in the vertical direction. The vibrating reed vibration detecting element 4 converts the actual vibration state of the metal vibrating reed 1 into an electric signal (an operation opposite to that of the piezoelectric driving vibrating element 3), and outputs the vibration information to an external drive circuit as a feedback signal. Output.

It is described that the piezoelectric vibration drive element 3 and the vibrating piece vibration detecting element 4 have electrodes formed on both main surfaces of the piezoelectric ceramic substrate. By omitting the electrodes, the metal vibrating reed 1
The piezoelectric vibration drive element 3 and the vibrating piece vibration detection element 4 may be adhered to the above.

A drive circuit for supplying a predetermined drive signal to the piezoelectric vibration drive element 3 and simultaneously performing a predetermined process based on a feedback signal of the resonator element vibration detection element 4, for example, an IC chip, is provided inside the container 5. And various electronic components are arranged.

The above-described piezoelectric vibrator is driven by the operation shown in the block circuit diagram of FIG.

In FIG. 3, reference numeral 31 denotes the piezoelectric vibration driving element 3.
And a vibrating element in which the vibrating piece vibration detecting element 4 and the vibrating piece vibration detecting element 4 are integrally symbolized, 32 is a switching means of a transistor, 33 is a bias oscillating circuit, and 34 is mainly composed of an amplifying means such as a transistor and a buffer. Have been.

The driving signal d is obtained by amplifying the oscillation output of the bias oscillation circuit 33 by the amplifying means 34, and the amplified signal is supplied to the piezoelectric vibration driving element 3 of the vibrating element 31 via the switching means 34. become.

Here, the important point is that the piezoelectric vibration driving element 3
Vibrating piece 1 including resonance frequency of
Is related to the natural frequency (frequency). That is, the natural frequency (frequency) of the metal vibrating reed 1 including the low-frequency vibrating weight 2
When the resonance frequency of the piezoelectric vibration driving element 3 is matched with the resonance frequency of the piezoelectric vibration driving element 3, the vibration energy of the piezoelectric vibration driving element 3 can be given to the metal vibrating piece 1 to the maximum. Will be done. Therefore, it is necessary to set the resonance frequency of the piezoelectric vibration drive element 3 so as to match the natural frequency of the metal vibrating reed 1, for example, 70 Hz. However, in practice, it is very difficult to match the resonance frequency of the piezoelectric vibration driving element 3 to the natural resonance frequency of the metal vibrating reed 1, and as a result, the vibration of the piezoelectric vibration driving element 3 can be efficiently reduced. 1 cannot be propagated.

In order to solve this problem, based on the feedback signal f of the vibrating element vibration detecting element 4 of the vibrating element 31,
The drive signal d supplied to the piezoelectric vibration drive element 3 is controlled so as to promote the actual vibration of the metal vibrating reed 1.

Since the feedback signal f is arranged on the surface of the metal vibrating reed 1, it is a signal indicating the actual vibration frequency of the metal vibrating reed 1.

In FIG. 3, the feedback signal f is supplied to the switch 32. Therefore, the drive signal d supplied to the piezoelectric vibration drive element 3 via the switch means 32 is
ON-OFF in synchronization with the HL fluctuation of the feedback signal f.
Operate. That is, the operating frequency of the switch means 32 can be matched with the vibration frequency of the metal vibrating reed 1 that actually vibrates.

As a result, the piezoelectric vibration drive element 3 can generate a vibration that causes the most efficient vibration of the actual metal vibrating reed 1.

The feedback signal f is supplied to the bias oscillation circuit 33 at the same time. And the bias oscillation circuit 33
The oscillating output output from is amplified by the amplifying means 34, and the oscillating output is converted into a high voltage that can cause the piezoelectric vibration driving element 3 to perform a large displacement operation.

More specifically, the bias oscillation circuit 33 performs a logical operation, for example, a NAND operation, on the clock signal of the bias clock generation unit and the feedback signal f, and amplifies a signal synchronized with the feedback signal d with a buffer amplifier. ing. The oscillation output thus amplified is further amplified by the amplification means 34.

In the drawing, a resistor R is a resistor for removing noise of a harmonic component generated by processing a rectangular signal.

The driving signal d supplied to the piezoelectric vibration driving element 3 for driving the metal vibrating reed 1 is based on the feedback signal f indicating the actual vibration state of the metal vibrating reed 1, Vibration is a signal that can efficiently give vibration energy to the metal vibrating reed 1. Moreover, the processing is performed so that the piezoelectric vibration drive element 3 can be largely displaced by the clock signal amplification processing.

FIG. 4 is a block circuit diagram of another drive circuit.

In FIG. 3, although the oscillation output is amplified by the amplifying means 34 and the like, and the switch means 32 which turns on and off finally in synchronization with the actual vibration of the metal vibrating piece 1 is used, In this embodiment, a drive signal d of a high voltage (high wave height) rectangular wave is directly derived without using a switch means.

That is, in the figure, reference numeral 41 denotes a clock generation circuit, and reference numeral 42 denotes a clock signal addition logic circuit for adding a clock signal.

The feedback signal d is supplied to a clock signal addition logic circuit 42 via a clock generation circuit 41.

The clock generation circuit 41 generates a rectangular wave having a relatively high frequency, for example, 5 to 10 kHz, following the feedback signal d. A clock signal having an extremely high frequency as compared with the frequency of such an actual vibration is added by the clock signal addition logic circuit 42 based on the feedback signal d. As a result, the driving signal d supplied to the piezoelectric vibration driving element 3 for driving the metal vibrating reed 1
Is a drive signal that gives the vibration of the piezoelectric vibration drive element 3 vibration energy to the metal vibrating reed 1 based on the feedback signal f indicating the actual vibration state of the metal vibrating reed 1. For example, FIG.
The clock signal shown in FIG. 5A is changed into a drive signal d shown in FIG. Therefore, the processing is performed so that the piezoelectric vibration drive element 3 can be largely displaced by the clock signal addition processing.

As described above, in each of the drive circuits, the vibrating bar vibration detecting element 4 for outputting a signal indicating the actual vibration state of the metal vibrating bar 1 is arranged, and the driving is performed based on the feedback signal f. The signal d is formed.

In FIG. 4, the resistor R is a resistor for smoothing the rise and fall of the rectangular wave drive signal and smoothing the operation of the vibrating element R.

The above-mentioned circuit, that is, a DC-DC converter circuit and a piezoelectric vibration driving element which is a vibration source of the vibrator can provide a vibrator which is smaller than the conventional vibrator. In addition, a vibration following the actual vibration of the metal vibrating reed 1 can be generated by the piezoelectric vibration driving element 3, and a high-voltage driving signal can be easily formed. Therefore, even when the piezoelectric driving vibration element is used, a sufficiently large vibration displacement can be easily obtained, and the actual vibration displacement of the metal vibrating piece 1 including the low-frequency vibrating weight 2 is not attenuated.

In the above-described embodiment, the piezoelectric vibration driving element attached to the metal vibrating reed 1 may be of a bimorph type attached to the upper and lower main surfaces of the metal vibrating reed 1.

[0049]

According to the present invention, it is possible to optimally follow the vibration of the piezoelectric vibration driving element according to the actual vibration of the metal vibrating piece. Therefore, there is no deviation between the vibration of the metal vibrating piece and the vibration frequency of the piezoelectric vibration driving element, and the most efficient and large vibration displacement can be generated in the metal vibrating piece.

Further, the driving signal has a high voltage by amplifying, superimposing and adding a rectangular wave. For this reason, large vibration can be easily generated in the piezoelectric driving vibration element.

As a result, the practicality of the piezoelectric vibrator that can be reduced in size and power consumption can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a piezoelectric vibrator according to the present invention.

FIG. 2 is a plan view of a metal vibrating reed of the piezoelectric vibrator according to the present invention.

FIG. 3 is a block circuit diagram of the piezoelectric vibrator of the present invention.

FIG. 4 is another block circuit diagram of the piezoelectric vibrator of the present invention.

5A is a schematic diagram showing a pulse of a clock signal, and FIG. 5B is a schematic diagram showing a pulse of a drive signal in the block circuit diagram shown in FIG. 4;

[Description of Signs] 1... Plate-shaped metal vibrating piece 2... Low-frequency vibrating weight 3... 32 switch means 33 bias oscillation circuit 34 amplifying means 41 clock generation circuit 42 clock signal addition logic circuit d drive signal f feedback signal

Claims (2)

[Claims] A plate-shaped metal vibrating piece having one end serving as a fixed end and the other end serving as a free end to which a low-frequency vibrating weight is attached; a piezoelectric driving vibrating element disposed on a surface of the plate-shaped metal vibrating piece; A vibrating reed vibration detecting element, switch means operating based on a feedback signal output from the vibrating reed vibration detecting element, a bias oscillation circuit for oscillating and outputting based on the feedback signal, and amplifying means; The oscillation output of the oscillation circuit is amplified by the amplification means,
A piezoelectric vibrator, wherein the piezoelectric vibrator is operated with a drive signal of a predetermined frequency synchronized with the feedback signal by the switch means operating based on the feedback signal. 2. A plate-shaped metal vibrating piece having one end serving as a fixed end and the other end serving as a free end having a low-frequency vibrating weight attached thereto, a piezoelectrically driven vibration element disposed on the surface of the plate-shaped metal vibrating piece, and A vibrating bar vibration detecting element, an oscillation circuit that generates a rectangular wave clock signal based on a feedback signal output from the vibrating bar vibration detecting element, and a high wave height by adding the rectangular wave clock signal based on the feedback signal. And a clock signal addition logic circuit for converting the output signal of the clock signal addition logic circuit corresponding to the feedback signal into a drive signal to operate the piezoelectric drive vibration element.