JPH05161877A - Piezoelectric ceramic oscillator - Google Patents

Abstract

PURPOSE:To provide a piezoelectric ceramic oscillator generating ultrasonic wave by transmitting mechanical vibration to a diaphragm. CONSTITUTION:A piezoelectric oscillator 1 consists of a piezoelectric porcelain 3 and electrodes 4 and 5 provided on both end faces being vertical to its thickness direction. The piezoelectric ceramic oscillator 1 forms an ultrasonic wave generating element by fixing a tongue piece-like diaphragm 2 on one of the end faces having the electrodes. The piezoelectric oscillator 1 is excitedly oscillated by applying high frequency electric voltage and the oscillation is transmitted to the diaphragm 2, which is oscillated. The structure becomes thereby simple, small and lightweight. When it is applied for an ultrasonic atomizing apparatus, atomizing efficiency, a large amt. of atomizing, fineness of particles and uniformity of particles can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention transmits a mechanical vibration to a diaphragm which is excited by a high frequency voltage and mechanically vibrates at a frequency of the high frequency voltage, and a part of which is fixed to the surface and the rest of which is projected from the surface. The present invention relates to a piezoelectric ceramic vibrator that generates an ultrasonic wave by doing so.

[0002]

2. Description of the Related Art An ultrasonic atomizer is one of the applications of piezoelectric ceramic vibrators. Examples of the conventional ultrasonic atomizer include an ultrasonic atomizer and a nebulizer to which a bolted Langevin type vibrator is applied. The atomization device using the bolted Langevin type vibrator uses ultrasonic waves with a frequency of several tens of kHz, and has the advantage of being able to generate a large amount of fog, but it has the disadvantages of a complicated structure and large-scale element. Hold. On the other hand, the nebulizer uses ultrasonic waves in the MHz range and has the advantage that the particles are minute and has excellent uniformity, but it has the disadvantage that atomization efficiency is poor and it is difficult to generate a large amount of fog with low power. Hold. That is, the conventional ultrasonic atomizer has a problem in atomization efficiency, large amount of atomization, fineness of particles, or driving power supply cost.

[0003]

However, the conventional ultrasonic atomizer has a problem in atomization efficiency, large amount atomization at low power, fineness of particles, or driving power supply cost.

The object of the present invention is to improve atomization efficiency, large amount of atomization, fineness and uniformity of particles, small size and light weight of device, simple structure and cost of driving power source. The object is to provide a piezoelectric ceramic oscillator which forms part of a satisfactory ultrasonic atomizer.

[0005]

A piezoelectric ceramic vibrator according to claim 1 is excited by a high-frequency voltage and mechanically vibrates at a frequency of the high-frequency voltage, and a part of the surface is fixed and the rest is projected from the surface. Piezoelectric ceramic vibrators that generate ultrasonic waves by transmitting the mechanical vibrations to a vibrating plate, and a piezoelectric ceramic and first and second piezoelectric elements provided on both end surfaces of the piezoelectric ceramic perpendicular to the thickness direction. And an electrode of.

The piezoelectric ceramic vibrator according to a second aspect of the invention is characterized in that at least one of the first and second electrodes is divided into two portions which are insulated from each other.

According to a third aspect of the present invention, there is provided a piezoelectric ceramic vibrator which is a rectangular plate having a length-width dimension ratio close to 1 and not equal to 1 in a cross section perpendicular to the thickness direction. ..

According to another aspect of the piezoelectric ceramic vibrator of the present invention, the dimensional ratio between the thickness in the thickness direction and the length of one side in a cross section perpendicular to the thickness direction is close to 1 and is not equal to 1. It is characterized by being a prismatic shape.

According to a fifth aspect of the present invention, there is provided a piezoelectric ceramic vibrator having a through hole penetrating in parallel with the thickness direction.

According to a sixth aspect of the present invention, the piezoelectric ceramic vibrator has a frame-shaped structure in a cross section perpendicular to the thickness direction,
The ratio of the length in the thickness direction to the shortest distance between the outer edge and the inner edge of the frame mold is substantially equal to 1.

According to a seventh aspect of the present invention, there is provided a piezoelectric ceramic vibrator in which the frame shape is an annular shape.

[0012]

A piezoelectric ceramic vibrator according to a first aspect of the invention comprises a piezoelectric ceramic and first and second electrodes formed on both end faces perpendicular to the thickness direction thereof. When a high frequency voltage is applied through the electrodes, the piezoelectric ceramic vibrator is excited and mechanically vibrates at the frequency of the high frequency voltage. Since the diaphragm is fixed to the piezoelectric ceramic vibrator via a part of the diaphragm, the mechanical vibration is transmitted to the diaphragm. In this way, the piezoelectric ceramic vibrator of the present invention generates ultrasonic waves by transmitting the mechanical vibration to the diaphragm. An ultrasonic atomization device is formed by providing the piezoelectric ceramic vibrator with the vibrating plate and providing the vibrating plate with appropriate water supply means. When the ultrasonic atomizer is used, an AC signal having a frequency substantially equal to the resonance frequency of the composite of the piezoelectric ceramic oscillator and the vibration plate is applied to the piezoelectric ceramic oscillator, Be excited. The excitation of the piezoelectric ceramic vibrator vibrates the diaphragm, and the liquid supplied to the diaphragm is atomized. Therefore, since the ultrasonic atomizing device having such a simple structure is formed by adopting the piezoelectric ceramic vibrator of the present invention, it is possible to reduce the size and weight of the ultrasonic atomizing device and atomize the liquid with high efficiency. be able to.

In the piezoelectric ceramic vibrator according to a second aspect of the invention, the electrode formed on the one end face is divided into two parts which are insulated from each other, so that the piezoelectric ceramic vibrator is provided on one of the parts. The electrodes can be used as electrodes for self-excited power supplies. Therefore, not only the structure is simple, but also the elastic vibration can be generated with low power consumption, stable and efficient.

The piezoelectric ceramic vibrator according to a third aspect of the invention is a rectangular plate in which the dimension ratio of length to width in a cross section perpendicular to the thickness direction is close to 1 and is not equal to 1. The coupled vibration of the composite of the ceramic vibrator and the diaphragm is enhanced. Therefore, the excitation of the piezoelectric ceramic vibrator is effectively transmitted to the diaphragm.

According to another aspect of the piezoelectric ceramic vibrator of the present invention, the dimensional ratio between the thickness in the thickness direction and the length of one side in a cross section perpendicular to the thickness direction is close to 1 and is not equal to 1. Since it is a prismatic shape, the combined vibration of the composite of the piezoelectric ceramic vibrator and the vibration plate is enhanced. Therefore, the excitation of the piezoelectric ceramic vibrator is effectively transmitted to the diaphragm.

Since the piezoelectric ceramic vibrator according to claim 5 has a through hole penetrating in parallel with the thickness direction, the piezoelectric ceramic vibrator is provided at a position covering the opening of the through hole or inside the through hole. The vibrating plate can be provided substantially parallel to the end surface of the porcelain perpendicular to the thickness direction. Therefore, since the diaphragm vibrates integrally with the piezoelectric ceramic vibrator, the vibration energy of the piezoelectric ceramic vibrator efficiently propagates to the diaphragm to vibrate the diaphragm.

According to a sixth aspect of the piezoelectric ceramic vibrator, a cross section perpendicular to the thickness direction has a frame structure.
Since the ratio of the length in the thickness direction to the shortest distance between the outer edge and the inner edge of the frame mold is substantially equal to 1, the coupled vibration of the composite of the piezoelectric ceramic oscillator and the diaphragm is enhanced.
Therefore, the vibration energy of the piezoelectric ceramic vibrator efficiently propagates to the diaphragm, causing the diaphragm to vibrate.

In the piezoelectric ceramic vibrator according to a seventh aspect of the present invention, since the frame is annular, the ratio of the length in the thickness direction to the shortest distance between the outer edge and the inner edge of the annular ring is almost equal. Since it is equal to 1, the combined vibration of the composite body of the piezoelectric ceramic vibrator and the vibration plate is enhanced. Therefore, the vibration energy of the piezoelectric ceramic vibrator efficiently propagates to the diaphragm, causing the diaphragm to vibrate.

[0019]

1 is a side view showing an embodiment of an ultrasonic wave generating element formed by a piezoelectric ceramic vibrator of the present invention. The ultrasonic wave generating element of the present embodiment is a composite body including a piezoelectric vibrator 1 to which terminals P and Q made of copper foil are attached and a diaphragm 2. The piezoelectric vibrator 1 has a rectangular plate-shaped piezoelectric ceramic 3, and the material of the piezoelectric ceramic 3 is TDK72A material (product name), and the length is 22 mm, the width is 20 mm, and the thickness is 1 mm. Since the TDK72A material has a large electromechanical coupling coefficient, it is used in this example. Piezoelectric ceramic 3
The direction of the polarization axis of is aligned with the thickness direction, and Au electrodes 4 and 5 are formed on both end faces perpendicular to the thickness direction.
The Au electrode 4 covers one surface of the piezoelectric ceramic 3 and the Au electrode 5
Covers the other surface of the piezoelectric ceramic 3. Au electrode 4
Has a terminal P attached thereto, and the Au electrode 5 has a terminal Q attached thereto. The terminals P and Q are arranged at one edge of the piezoelectric ceramic 3 along the width direction. A tongue-shaped diaphragm 2 is attached to one surface of the piezoelectric vibrator 1.

FIG. 2 is a plan view of the ultrasonic wave generating element of FIG. The vibrating plate 2 is made of nickel and is fixed integrally with the piezoelectric vibrator 1 at the long and thin plate-shaped fixing portion 6. The vibrating plate 2 protruding from the piezoelectric vibrator 1 forms the vibrating part 7. ing. The fixing portion 6 is bonded to the piezoelectric vibrator 1 via the Au electrode 4 with an adhesive. The diaphragm 2 has a length of 20 mm, a width of 20 mm and a thickness of 0.05 mm. Fixed part 6
Has a length of 20 mm, a width of 3 mm and a thickness of 0.05 mm. The vibrating portion 7 extends and protrudes outward from an edge portion along the width direction of the piezoelectric vibrator 1 in parallel to the plate surface of the piezoelectric vibrator 1. The vibrating portion 7 has a length of 17 mm, a width of 20 mm, and a thickness of 0.05 mm.

FIG. 3 is a partially enlarged plan view of the vibrating portion 7 in FIG. 2, and FIG. 4 is a sectional view of the vibrating portion 7 that appears when cut along a plane perpendicular to the plate surface. The vibrating portion 7 is provided with a large number of fine holes 8 penetrating in the thickness direction thereof. The hole 8 is shaped like a mortar, and one having an opening area larger than that of the other is used in this embodiment, and one opening serves as an inlet side and the other serves as an outlet side. The diameter of the inlet side is 0.1 mm, the diameter of the outlet side is 0.02 mm, and the holes 8 are arranged at the same pitch.

FIG. 5 shows a piezoelectric vibrator 11 having a length of 20 mm, a width of 5 mm and a thickness of 6 mm, and a length of 10.5 mm, a width of 5 mm and a thickness of 0.0.
4mm vibrating part 17 and length 1.5mm, width 5mm, thickness 0.0
FIG. 3 is a perspective view showing an example of an ultrasonic wave generation element provided with a vibration plate 16 having a fixing portion 18 of 4 mm. The vibrating portion 17 is provided with a large number of fine holes penetrating in its thickness direction, and the shape of the holes is the same as the hole 8 in FIGS. 3 and 4, but the diameter on the inlet side is 0.06 mm. , The diameter of the outlet side is 0.
It is 01 mm. Electrodes 13, 14, and 15 are formed on both end surfaces of the piezoelectric ceramic 12 perpendicular to the polarization axis. The electrodes 13 and 14 are provided on the same surface and are insulated from each other. The electrode 13 is 15 mm from the end of the piezoelectric ceramic in the length direction.
And is used as an electrode for applying an alternating voltage to the piezoelectric vibrator 11. Electrode 14 is from electrode 13 to 1
It covers the rest of mm apart and is used as an electrode for a self-excited power supply. It was confirmed that the ultrasonic atomizing device using the ultrasonic wave generating element of the present example has a maximum atomization amount at a frequency of about 100 kHz and the particles of the fog are minute and uniform.

FIG. 6 is a sectional view showing an embodiment in which the ultrasonic wave generating element shown in FIG. 1 is applied to an ultrasonic atomizing device. In this embodiment, the ultrasonic wave generating element shown in FIG.
1, a liquid retaining material 22 and a support 23. FIG. 6 also shows a power supply circuit for supplying an AC voltage to the piezoelectric vibrator 1, and the liquid storage chamber 21 is filled with an appropriate amount of liquid during use. The tip of the liquid retaining material 22 is in contact with the lower surface of the diaphragm 2. The end of the liquid retaining material 22 is fixed to the lower end of the liquid storage chamber 21, and sucks the liquid in the liquid storage chamber 21 and contacts the vibration plate 2 to supply the liquid to the lower surface of the vibration plate 2.

When the ultrasonic atomizer of FIG. 6 is driven, an AC signal having a frequency substantially equal to the intermediate value of the two resonance frequencies in the composite of the piezoelectric vibrator 1 and the diaphragm 2 is applied to the terminals P and Q. It is applied to the piezoelectric vibrator 1 via At this time, the frequency of the AC signal substantially matches the resonance frequency of the piezoelectric vibrator 1. The piezoelectric vibrator 1 is excited, and the vibrating plate 2 is vibrated in the form of a cantilever whose fixed end 6 is a fixed end. The support base 23 that fixes the piezoelectric vibrator 1 to the liquid storage chamber 21 is made of styrofoam, and has a lower acoustic impedance than the piezoelectric vibrator 1 and is used in this embodiment. Since the support base 23 is made of styrofoam, the ultrasonic waves from the piezoelectric vibrator 1 are prevented from propagating to the support base 23 itself and being lost, and the diaphragm 2 is efficiently vibrated. On the other hand, the liquid in the liquid storage chamber 21 is sucked up by the liquid retaining material 22 and reaches the lower surface of the diaphragm 2. Liquid retaining material 2
No. 2 is made of sponge and not only has a high liquid absorption capacity, but also has a lower acoustic impedance than the piezoelectric vibrator 1, and therefore is used in this example. Since the liquid retaining material 22 is made of sponge, ultrasonic waves from the piezoelectric vibrator 1 are transmitted to the liquid retaining material 2.
The vibration plate 2 is suppressed from propagating through the liquid and being scattered, and the diaphragm 2 is efficiently vibrated. The elastic vibration generated in the vibrating portion 7 effectively functions for atomizing the liquid. With the vibration of the vibrating portion 7, the liquid supplied to the lower surface of the vibrating plate 2 is guided to each hole 8 by the capillary phenomenon. When the liquid passes through the holes 8, the passage area of the liquid in the holes 8 decreases from the inlet side to the outlet side, so that the liquid receives the throttling action by the holes 8 and flows out to the upper surface of the vibrating portion 7. To do. As a result, the liquid flowing out from the hole 8 is efficiently atomized by the diaphragm action and the bending vibration of the vibrating portion 7. According to the ultrasonic atomizing device of this embodiment, when the applied voltage is 9.8V, the frequency is 114.
The amount of atomization becomes maximum at 6kHz, and the power consumption at that time is 2
94mW, current is 30mA. The power consumption of the entire device including the power supply is 588 mW and the current is 60 mA.

FIG. 7 is a characteristic diagram showing the relationship between the length of the vibrating portion 7 and the atomization amount when the length of the vibrating portion 7 is changed in the ultrasonic wave generating element shown in the embodiment of FIG. is there. The maximum amount of atomization is 27.5 ml when the length of the vibrating part is 17 mm.
Indicates / min. FIG. 8 is a characteristic diagram showing the relationship between the length of the vibrating portion 7 and the height of the mist jet. However, the height at this time is the value that is what is ejected in the oblique direction converted to the value above vertically. When the vibrating part 7 has a length of 17 mm, the fog height is 1
The maximum value of 12 cm is reached.

FIG. 9 is a characteristic diagram showing the relationship between impedance phase and frequency of the piezoelectric vibrator 1 of the embodiment of FIG. 1, and FIG. 10 shows the piezoelectric vibrator 1 and the diaphragm 2 of the embodiment of FIG. FIG. 3 is a characteristic diagram showing the relationship between impedance phase and frequency for the composite of FIG. Since the value of the frequency when the phase is 0 degree indicates the resonance frequency, the piezoelectric vibrator 1 has four resonance frequencies in FIG. 9. fa represents an intermediate value of two resonance frequencies of the four resonance frequencies. In FIG. 10, the peak near fa is divided into two, and the resonance frequency fb1
, Fb2, and the intermediate value f0 indicates the frequency at which the atomization amount becomes maximum, and f0 substantially matches fa. As the length of the vibrating portion 7 is shortened, fb1 and fb2 shift to the high frequency side and move away from fa, so that the atomization amount decreases.

FIG. 11 is a perspective view showing an embodiment of an ultrasonic wave generating element comprising a piezoelectric vibrator 60 and a vibrating plate 70 (not shown in the figure), and FIG. It is a top view when the sound wave generator is seen from the lower surface direction. This embodiment is used in place of the ultrasonic wave generating element of FIG. 1 attached to the support base 23 in the ultrasonic atomizing device of FIG. The piezoelectric ceramic 61 has a columnar shape, and has holes penetrating in parallel to the polarization axis with both end surfaces perpendicular to the polarization axis as end faces. The material of the piezoelectric ceramic 61 is TDK72A material (product name)
The diameter is 24 mm, the thickness is 6 mm, the through hole is also cylindrical, and the diameter is 12 mm. Since the TDK72A material has a large electromechanical coupling coefficient, it is used in this example. An Au electrode 62 and an Au electrode 63 are formed on both end faces, respectively. A terminal P is attached to the Au electrode 62, and a terminal Q is attached to the Au electrode 63.

A disk-shaped vibrating plate 70 is attached to the lower end surface of the piezoelectric vibrator 60 at a position covering the opening of the through hole. The vibration plate 70 is made of nickel and has a ring-shaped fixing portion 72.
The vibrating plate 70, which is integrally connected to the piezoelectric vibrator 60 and is fixed by the vibrating plate 70, is surrounded by the fixing portion 72 to form the vibrating portion 71. The fixed portion 72 is fixed to the piezoelectric vibrator 60 via the Au electrode 63. The diameter of the diaphragm 70 is 14 m
m, thickness is 0.05 mm. The vibrating portion 71 has a diameter of 12 mm, which corresponds to the diameter of the through hole, and has a thickness of 0.0
It is 5 mm. The vibrating portion 71 is provided with a large number of fine holes penetrating in its thickness direction, and the size and shape of the holes are the same as the holes 8 in FIGS. 3 and 4. The composite body including the piezoelectric vibrator 60 and the vibrating plate 70 is attached to the support plate 23 with the vibrating portion 71 in contact with the liquid retaining material 22.

When the ultrasonic atomizing device of FIG. 6 equipped with the ultrasonic wave generating elements of FIGS. 11 and 12 instead of the ultrasonic wave generating element of FIG. 1 is driven, a frequency substantially equal to the resonance frequency of the composite is generated. The AC signal which it has is applied to the piezoelectric vibrator 60 via the terminal P and the terminal Q. The piezoelectric vibrator 60 is excited, and the vibrating portion 71 surrounded by the fixed portion 72 is the piezoelectric vibrator 60.
It vibrates as a unit. The combined vibration of the vibrating portion 71 effectively functions for atomizing the liquid.

FIG. 13 is a characteristic chart showing the relationship between the applied voltage and frequency and the power consumption and current at that time for the composite body of FIG. 11 having three shapes. Type I and I
In the I type, a vibration plate is fixed to the lower end of the piezoelectric vibrator. I
The II type has the same dimensions as the II type, but the diaphragm is fixed to the upper end surface of the piezoelectric vibrator. Type II is shown in FIG. 11 and FIG.
This is a composite body of the piezoelectric vibrator 60 and the vibration plate 70 shown in FIG. When the applied voltage is 10.7V, the frequency is 290.
The amount of atomization becomes maximum at 6kHz, and the power consumption at that time is 3
20mW, current is 30mA. The power consumption of the entire device including the power supply is 642 mW and the current is 60 mA. It should be noted that if a diaphragm is provided on the upper part of the same structure as the II type, the atomization rate is reduced while maintaining the characteristics of the II type, but it is effective for generating extremely fine mist. confirmed.

In addition to this embodiment as the liquid supply means, when the liquid is dropped on the vibration plate 2 or the vibration plate 70 without using the liquid retaining material 22, or the vibration plate 2 is formed by using the liquid supply tube. Alternatively, when the liquid is supplied to the lower surface of the vibration plate 70, the atomization effect similar to that of the present embodiment was observed.

Further, in addition to the present embodiment as the liquid supply means, the liquid retaining material 22 is fixed to the lower surface of the diaphragm 2 or the diaphragm 70 without being fixed to the lower end of the liquid storage chamber 21, and the liquid retaining material 22 is fixed. The same atomization effect as that of this example was also observed by immersing in the liquid or bringing it into contact with the liquid surface. The liquid retaining material 22 is fixed to a fixed object without using the liquid storage chamber 21, and the liquid is supplied to the liquid retaining material 22 using a liquid supply tube or the like, and the diaphragm 2 or the liquid retaining material 22 is supplied to the liquid retaining material 22. By bringing the diaphragm 70 into contact, the atomization effect similar to that of the present embodiment was observed. Suspend the liquid retaining material 22 from a fixed object with a thread or a string, supply the liquid to the liquid retaining material 22 through the thread or the string, and bring the diaphragm 2 or the diaphragm 70 into contact with the liquid retaining material 22. Also, the atomization effect similar to that of this example was observed. The same atomization effect as in this embodiment can be obtained by bringing the liquid retaining material 22 into contact with the diaphragm 2 or the diaphragm 70 by moving the liquid retaining material 22 or the ultrasonic atomizing device itself. I was seen. At that time, by attaching a timer, atomization can be performed every time, and by attaching a humidity sensor, the liquid retaining material 22 and the diaphragm 2 or the diaphragm 70 come into contact with or separate from each other to maintain a constant humidity. I was able to keep it.

[0033]

The piezoelectric ceramic vibrator of the present invention employs a simple structure including a piezoelectric ceramic and electrodes formed on both end faces perpendicular to the thickness direction of the piezoelectric ceramic. Therefore, the ultrasonic wave generating element including the piezoelectric ceramic vibrator and the vibration plate can be downsized. Further, since the electrode formed on the one end face is divided into two parts insulated from each other, the electrode provided on the one end part can be used as an electrode for a self-excited power supply. it can. Therefore, not only the structure is simple, but also the elastic vibration can be generated with low power consumption, stable and efficient.

By virtue of the adoption of the structure in which the vibration plate of the ultrasonic wave generating element formed by the piezoelectric ceramic vibrator of the present invention is integrally and integrally fixed on at least one surface having the electrodes of the piezoelectric ceramic vibrator, Vibrates with the fixed part as the fixed end. When an ultrasonic atomizing device is formed from such an ultrasonic wave generating element, the liquid supplied to the vibrating portion in the state of strong elastic vibration is atomized vertically upward. The vibrating part has a large number of minute holes, and by adopting a vibrating plate in which one opening area of the hole and the other opening area are different, vibration of the vibrating part The synergistic effect with the action of the holes provided facilitates the atomization action of the liquid, the amount of mist generated is increased, and the diameter of the particles is fine and uniform.

In the ultrasonic wave generating element formed by the piezoelectric ceramic vibrator of the present invention, the intermediate value of the two resonance frequencies in the composite of the piezoelectric ceramic vibrator and the diaphragm is almost equal to the resonance frequency of the piezoelectric ceramic vibrator alone. By adopting such a structure, the combined vibration of the composite of the piezoelectric ceramic vibrator and the diaphragm is enhanced. Therefore, the excitation of the piezoelectric ceramic vibrator is effectively transmitted to the diaphragm. In this way, in the ultrasonic atomization device formed by the piezoelectric ceramic vibrator of the present invention, atomization efficiency is promoted and the amount of fog generated is increased.

Since the piezoelectric ceramic forming a part of the piezoelectric ceramic vibrator of the present invention is a rectangular plate having a dimensional ratio of length and width in a cross section perpendicular to the thickness direction which is close to 1 and not equal to 1, The coupled vibration of the composite of the piezoelectric ceramic vibrator and the diaphragm is enhanced. Therefore, the excitation of the piezoelectric ceramic vibrator is effectively transmitted to the diaphragm. In this way, in the ultrasonic atomization device formed by the piezoelectric ceramic vibrator of the present invention, atomization efficiency is promoted and the amount of fog generated is increased.

The dimensional ratio between the thickness in the thickness direction of the piezoelectric ceramic forming a part of the piezoelectric ceramic vibrator of the present invention and the length of one side in the cross section perpendicular to the thickness direction is close to 1 and is 1 as well. Since the rectangular prisms are not equal to each other, the combined vibration of the composite of the piezoelectric ceramic vibrator and the vibration plate is enhanced. Therefore, the excitation of the piezoelectric ceramic vibrator is effectively transmitted to the diaphragm. In this way, in the ultrasonic atomization device formed by the piezoelectric ceramic vibrator of the present invention, atomization efficiency is promoted and the amount of fog generated is increased.

In the piezoelectric ceramic vibrator of the present invention, by adopting a columnar structure having a through hole penetrating in parallel to the thickness direction of the piezoelectric ceramic, a position covering the opening of the through hole and the inside of the through hole are adopted. The diaphragm can be provided substantially parallel to the end surface of the piezoelectric ceramic which is perpendicular to the thickness direction. Therefore, the vibrating plate performs combined vibration integrally with the piezoelectric ceramic vibrator, so that the vibration energy of the piezoelectric ceramic vibrator efficiently propagates to the vibrating plate and vibrates the vibrating plate. In this way, in the ultrasonic atomizer formed by the piezoelectric ceramic vibrator of the present invention, when the diaphragm having the structure having the holes in the vibrating part is used, the atomization efficiency of the liquid supplied to the diaphragm is improved. Not only can it be increased in size, but the size of the mist particles can be made minute and uniform. If a plurality of diaphragms are used, the fineness of fog particles can be further improved.

When the ultrasonic ceramic vibrator of the present invention adopts a columnar structure having a through hole, the shape of the cross section perpendicular to the thickness direction of the piezoelectric ceramic forms a frame type structure. Adopting a structure in which the ratio of the length in the thickness direction of the piezoelectric ceramic and the shortest distance between the outer edge and the inner edge of the frame type is approximately equal to 1, the coupled vibration of the composite of the piezoelectric ceramic oscillator and the diaphragm is enhanced. To be done. Therefore,
The vibration energy of the piezoelectric ceramic vibrator efficiently propagates to the diaphragm, causing the diaphragm to vibrate. In this way, in the ultrasonic atomization device formed by the piezoelectric ceramic vibrator of the present invention, atomization efficiency is promoted and the amount of fog generated is increased.

The piezoelectric ceramic vibrator of the present invention employs an annular structure as the frame type, and the ratio of the length in the thickness direction of the piezoelectric ceramic to the shortest distance between the outer edge and the inner edge of the annular ring is approximately 1 By adopting a structure equal to, the combined vibration of the composite of the piezoelectric ceramic vibrator and the diaphragm is enhanced.
Therefore, the vibration energy of the piezoelectric ceramic vibrator efficiently propagates to the diaphragm and vibrates the diaphragm. In this way, in the ultrasonic atomization device formed by the piezoelectric ceramic vibrator of the present invention, atomization efficiency is promoted and the amount of fog generated is increased.

Increasing the applied voltage of the ultrasonic atomizer formed by the piezoelectric ceramic vibrator of the present invention increases the coupled vibration of the composite of the piezoelectric ceramic vibrator and the diaphragm. Therefore, the atomization amount can be freely changed by changing the voltage according to the purpose.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of an ultrasonic wave generation element formed by a piezoelectric ceramic vibrator of the present invention.

FIG. 2 is a plan view of the ultrasonic wave generation element of FIG.

FIG. 3 is a partially enlarged plan view of a vibrating section 7 of FIG.

FIG. 4 is a cross-sectional view of the vibrating portion 7 that appears when cut along a plane perpendicular to the plate surface.

FIG. 5 is a perspective view showing an embodiment of an ultrasonic wave generating element including the piezoelectric ceramic vibrator of the present invention.

6 is a cross-sectional view showing an embodiment in which the ultrasonic wave generating element shown in FIG. 1 is applied to an ultrasonic atomizing device.

FIG. 7 is a diagram showing an ultrasonic wave generating element shown in the embodiment of FIG.
The characteristic view which shows the relationship between the length of the vibration part 7 and the amount of atomization when changing the length of the vibration part 7.

FIG. 8 is a diagram showing an ultrasonic wave generating element shown in the embodiment of FIG.
FIG. 6 is a characteristic diagram showing the relationship between the length of the vibrating section 7 and the height of mist ejection.

9 is a characteristic diagram showing the relationship between impedance phase and frequency of the piezoelectric vibrator 1 of the embodiment of FIG.

10 is a characteristic diagram showing the relationship between impedance phase and frequency for a composite of the piezoelectric vibrator 1 and the diaphragm 2 of the embodiment of FIG.

FIG. 11 is a perspective view showing an embodiment of an ultrasonic wave generating element including a piezoelectric vibrator 60 and a vibration plate 70 (not shown in the figure).

FIG. 12 is a plan view of the ultrasonic wave generation element of FIG. 11 when viewed from the bottom surface direction.

13 is a characteristic diagram showing the relationship between applied voltage and frequency and power consumption and current at that time for the composite body of FIG. 11 having three types of shapes.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric vibrator 2 Vibrating plate 3 Piezoelectric ceramic 4 Electrode 5 Electrode 6 Fixing part 7 Vibrating part 8 Hole 11 Piezoelectric vibrator 12 Piezoelectric vibrator 13 Electrode 14 Electrode 15 Electrode 16 Vibrating plate 17 Vibrating part 18 Fixing part 21 Liquid storage chamber 22 Liquid material 23 Support base 60 Piezoelectric vibrator 61 Piezoelectric ceramics 62 Electrode 63 Electrode 70 Vibrating plate 71 Vibrating part 72 Fixed part

Claims (7)

[Claims] 1. An ultrasonic wave is generated by being excited by a high-frequency voltage to cause mechanical vibration at the frequency of the high-frequency voltage, and transmitting the mechanical vibration to a diaphragm that is partially fixed to the surface and overhangs the rest from the surface. A piezoelectric ceramic oscillator generated, comprising: a piezoelectric ceramic and first and second electrodes provided on both end faces perpendicular to the thickness direction of the piezoelectric ceramic. 2. The piezoelectric ceramic vibrator according to claim 1, wherein at least one of the first and second electrodes is divided into two parts which are insulated from each other. 3. The piezoelectric ceramic according to claim 1, which is a rectangular plate having a dimensional ratio of length to width in a cross section perpendicular to the thickness direction close to 1 and not equal to 1. Oscillator. 4. A rectangular prism having a dimensional ratio close to 1 and not equal to 1 in the dimensional ratio between the thickness in the thickness direction and the length of one side in a cross section perpendicular to the thickness direction. The piezoelectric ceramic oscillator according to claim 1. 5. The piezoelectric ceramic vibrator according to claim 1, wherein the piezoelectric ceramic vibrator has a through hole penetrating in parallel with the thickness direction. 6. The shape of a cross section perpendicular to the thickness direction forms a frame-shaped structure, and the ratio of the length in the thickness direction to the shortest distance between the outer edge and the inner edge of the frame shape is substantially equal to 1. The piezoelectric ceramic vibrator according to claim 5, wherein 7. The piezoelectric ceramic vibrator according to claim 6, wherein the frame shape is an annular shape.