JP2599844B2 - Ultrasonic generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave generating element having a vibration plate fixed to a piezoelectric vibrator.

[0002]

2. Description of the Related Art An ultrasonic atomizer is one of the applications of ultrasonic generators. Examples of the ultrasonic atomizing device using the conventional ultrasonic wave generating element include an ultrasonic atomizing device and a nebulizer to which a bolted Langevin type vibrator is applied. The atomization device using a bolted Langevin type vibrator uses ultrasonic waves with a frequency of several tens of kHz and has the advantage of generating a large amount of fog, but also has the disadvantage of a complicated structure and a large element Have. Nebulizers, on the other hand, use ultrasonic waves in the MHz range and have the advantage of fine particles and excellent uniformity, but have the disadvantage of poor atomization efficiency and the difficulty of generating large amounts of fog with low power. Hold. That is, the conventional ultrasonic atomizer has a problem in atomization efficiency, mass atomization, fineness of particles, or driving power supply cost.

[0003]

A conventional ultrasonic atomizing apparatus using an ultrasonic generating element has a disadvantage in atomizing efficiency, large-volume atomization with low power, fineness of particles, or driving power supply cost. was there.

It is an object of the present invention to provide an atomizing efficiency, a large amount of atomization, fine and uniform particle size, a small and lightweight device, a simple structure, and a low driving power cost. It is to provide an ultrasonic generating element for a satisfactory ultrasonic atomizing device.

[0005]

An ultrasonic wave generating element according to claim 1 is an ultrasonic wave generating element in which a vibration plate is fixed to a piezoelectric vibrator, and the vibration plate penetrates in the thickness direction thereof. A large number of holes are provided, and the piezoelectric vibrator includes a columnar piezoelectric ceramic, and electrodes formed on both end surfaces perpendicular to the thickness direction of the piezoelectric ceramic, and one of the vibration plates in the hole. The opening area is different from the other opening area.

According to another aspect of the ultrasonic wave generating element of the present invention, the vibrating plate is integrally and fixedly adhered to at least one end surface of the piezoelectric vibrator, the end surface having electrodes of the piezoelectric vibrator. A vibrating part projecting substantially in parallel to the end face of the piezoelectric vibrator toward the side, and the hole is provided in the vibrating part.

According to a third aspect of the present invention, in the ultrasonic generating element, a resonance frequency of the piezoelectric vibrator is substantially equal to an intermediate value between two resonance frequencies in a composite body of the piezoelectric vibrator and the vibration plate. And

According to a fourth aspect of the present invention, in the ultrasonic generating element, the piezoelectric vibrator is a rectangular plate whose dimensional ratio between length and width is close to 1 and not equal to 1.

According to a fifth aspect of the present invention, in the ultrasonic generating element, the piezoelectric vibrator is a rectangular prism having a dimensional ratio of thickness to width close to 1 and not equal to 1.

According to a sixth aspect of the present invention, in the ultrasonic wave generating element, the electrodes formed on the one end face are insulated from each other.
It is divided into two parts.

An ultrasonic generating element according to a seventh aspect is provided. The piezoelectric ceramic has a through hole penetrating in parallel with the polarization axis of the piezoelectric ceramic, and the vibration plate has an end surface perpendicular to the polarization axis at a position covering the opening of the through hole or inside the through hole. The vibrating plate is fixed to at least one place substantially in parallel with the piezoelectric vibrator, and a peripheral edge of the vibrating plate is fixed to the piezoelectric vibrator. And the hole is provided in the vibrating part.

According to another aspect of the present invention, one of the resonance frequencies of the piezoelectric vibrator is substantially equal to one of the resonance frequencies of a composite of the piezoelectric vibrator and the vibration plate. It is characterized by

In the ultrasonic wave generating element according to claim 9, the piezoelectric vibrator is rectangular or annular, and the length in the direction of the polarization axis of the piezoelectric vibrator and the shortest distance between the outer edge and the inner edge of the end face. Is characterized in that the ratio to and is approximately equal to 1.

[0014]

When the ultrasonic atomizer using the ultrasonic generator according to claim 1 is used, the piezoelectric vibrator has a frequency substantially equal to a resonance frequency of a complex of the piezoelectric vibrator and the vibration plate. Is applied, and the piezoelectric vibrator is excited. Excitation of the piezoelectric vibrator causes the vibrating plate to vibrate, and the liquid supplied to the vibrating plate is atomized by the effect of a large number of holes provided in the vibrating plate. The piezoelectric vibrator comprises a piezoelectric ceramic and electrodes formed on both surfaces of the piezoelectric ceramic perpendicular to the thickness direction, and an alternating voltage is applied to the piezoelectric vibrator via the electrodes. In the ultrasonic generating element of the present invention, a piezoelectric vibrator having such a simple structure is employed, and a vibration plate is provided at a predetermined position with respect to the piezoelectric vibrator. Therefore, the ultrasonic atomizing device using the ultrasonic wave generating element of the present invention can downsize the device and can atomize the liquid with high efficiency. In addition, since the opening area of one of the holes provided in the diaphragm is different from the opening area of the other hole, the fineness and uniformity of the mist particles can be promoted. Further, by using a plurality of diaphragms, the fineness of the particles of the mist of the ultrasonic atomizing device can be improved.

According to a second aspect of the present invention, in the ultrasonic generating element, the vibrating plate is integrally and continuously fixed on at least one surface of the piezoelectric vibrator having electrodes.
Since the diaphragm vibrates in the form of a cantilever having the fixed portion as a fixed end, when liquid is supplied to the diaphragm, the liquid is atomized by its elastic vibration, and is vertically above the diaphragm. It is released as a fog toward. Due to the synergistic effect of the vibration of the vibrating part and the function of the hole provided in the vibrating part, the atomizing action of the liquid is promoted, and the amount of generated mist increases and the particle diameter becomes uniform.

In the ultrasonic wave generating element according to claim 3, since the resonance frequency of the piezoelectric vibrator is substantially equal to the intermediate value of the two resonance frequencies in the composite of the piezoelectric vibrator and the vibration plate, they are common. By applying a voltage having the resonance frequency of 1 to the piezoelectric vibrator, the diaphragm is efficiently excited. Therefore, when liquid is supplied to the diaphragm, atomization efficiency is promoted, and the amount of mist generated further increases.

In the ultrasonic wave generating device according to the fourth aspect, the piezoelectric vibrator has a dimension ratio of length to width close to 1 and 1
By virtue of the rectangular plate not being equal to, the coupled vibration of the composite of the piezoelectric vibrator and the vibration plate is enhanced.
Therefore, the atomization efficiency of the ultrasonic atomizer using the ultrasonic generating element of the present invention is promoted.

In the ultrasonic wave generating device according to the fifth aspect, the piezoelectric vibrator has a dimensional ratio of thickness to width close to one, and moreover, one.
Due to the rectangular prism not equal to the above, the combined vibration of the composite body of the piezoelectric vibrator and the vibration plate is enhanced. Therefore, the atomization efficiency of the ultrasonic atomizing device using the ultrasonic wave generating element of the present invention is promoted.

In the ultrasonic wave generating device according to the sixth aspect, since the electrode formed on the one end face is divided into two parts insulated from each other, it is provided on one of the parts. The electrodes can be used as electrodes for self-excited power supplies. Therefore, the ultrasonic generating element of the present invention can generate stable and efficient elastic vibration with low power consumption, so that the atomizing efficiency of the ultrasonic atomizing apparatus using the ultrasonic generating element of the present invention is improved. Be promoted.

[0020] In the ultrasonic generating element according to claim 7, the piezoelectric ceramic has a through-hole penetrating in parallel with the polarization axis of the piezoelectric ceramic, and the diaphragm covers an opening of the through-hole. Alternatively, the vibration energy of the piezoelectric vibrator is efficiently propagated to the vibration plate because the vibration energy is provided in at least one position substantially parallel to the end surface perpendicular to the polarization axis inside the through hole, and the vibration plate is Since it vibrates, the atomization efficiency of the ultrasonic atomization device using the ultrasonic wave generation element of the present invention can be increased. The vibrating part forms a vibrating part, and the vibrating part performs combined vibration integrated with the piezoelectric vibrator by forming a vibrating part. The supplied liquid is atomized by the combined vibration, and is emitted as a mist toward the upper side perpendicular to the diaphragm. Due to the synergistic effect of the vibration of the vibrating part and the action of the hole provided in the vibrating part, the atomization efficiency of the liquid supplied to the vibrating part is promoted, the amount of mist generated increases, and The diameter becomes uniform.

In one embodiment, one of the resonance frequencies of the piezoelectric vibrator is substantially equal to one of the resonance frequencies of a composite of the piezoelectric vibrator and the vibration plate. When the voltage is applied to the piezoelectric vibrator, the atomization efficiency of the ultrasonic atomizer using the ultrasonic generating element of the present invention is promoted, and the amount of mist generated further increases.

According to a ninth aspect of the present invention, the piezoelectric vibrator has a rectangular or annular shape, and has a length in a direction of a polarization axis of the piezoelectric vibrator and a shortest distance between an outer edge and an inner edge of the end face. By employing a structure having a ratio of approximately equal to 1, the combined vibration of the composite body of the piezoelectric vibrator and the vibration plate is enhanced. Therefore, the atomization efficiency of the ultrasonic atomizer using the ultrasonic generator of the present invention is further increased.

[0023]

1 is a side view showing an embodiment of an ultrasonic wave generating element of the present invention. As shown in this embodiment, the ultrasonic wave generating element of the present invention is a composite body including the piezoelectric vibrator 1 to which terminals P and Q made of copper foil are attached, and the vibrating plate 2. The piezoelectric vibrator 1 has a piezoelectric ceramic 3 having a rectangular plate shape. The material of the piezoelectric ceramic 3 is TDK72A (product name), its length is 22 mm, its width is 20 mm, and its thickness is 1 mm. TDK72
Material A is used in the embodiment here because it has a large electromechanical coupling coefficient. The direction of the polarization axis of the piezoelectric ceramic 3 coincides with the thickness direction, and the Au electrode 4 and the Au electrode 5 are formed on both surfaces perpendicular to this thickness direction. The Au electrode 4 covers one surface of the piezoelectric ceramic 3, and the Au electrode 5
Covers the other side of the. The Au electrode 4 has a terminal P
Are attached, and a terminal Q is attached to the Au electrode 5. 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. 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.
A portion of the vibrating plate 2 protruding from the piezoelectric vibrator 1 forms a vibrating portion 7. The fixing portion 6 is bonded to the piezoelectric vibrator 1 via an Au electrode 4 with an adhesive. The diaphragm 2 has a length of 20
mm, width 20 mm, and thickness 0.05 mm. The fixed portion 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 section 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 cross-sectional view of the vibrating portion 7 which 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 has a mortar shape, and one having an opening area larger than the other opening area is used in this embodiment, and one opening is used as an inlet side and the other is used as an outlet side. The diameter on the inlet side is 0.1 mm and the diameter on the outlet side is 0.02 mm, and the holes 8 are arranged at an equal 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. 4 is a perspective view showing an embodiment of an ultrasonic wave generating element including 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 on the outlet side is 0.
It is 01 mm. Electrodes 13, 14, 15 are formed on both 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 covers a portion 15 mm from the longitudinal end of the piezoelectric ceramic, and is used as an electrode for applying an AC voltage to the piezoelectric vibrator 11. Electrode 14 is 1 mm from electrode 13
Covers the rest of the distance and is used as an electrode for a self-excited power supply. It was confirmed that the ultrasonic atomizer using this example had the maximum amount of atomization at a frequency of about 100 kHz, and the fog particles were fine and uniform.

FIG. 6 is a sectional view showing an embodiment in which the ultrasonic generator shown in FIG. 1 is applied to an ultrasonic atomizer. 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 an intermediate value between two resonance frequencies in the composite of the piezoelectric vibrator 1 and the diaphragm 2 is applied to the terminals P and Q. To the piezoelectric vibrator 1. 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 having the fixed portion 6 as a fixed end. The support 23 for fixing the piezoelectric vibrator 1 to the liquid storage chamber 21 is made of polystyrene foam, and has a lower acoustic impedance than that of the piezoelectric vibrator 1 and is used in this embodiment. Since the support 23 is made of polystyrene foam, the propagation of the ultrasonic wave from the piezoelectric vibrator 1 to the support 23 itself and the loss of the ultrasonic wave are suppressed, and the diaphragm 2 is vibrated efficiently. 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
2 is made of sponge and used not only in the liquid absorbing ability but also in the acoustic impedance is lower than that of the piezoelectric vibrator 1 in this embodiment. Since the liquid retaining material 22 is made of sponge, the ultrasonic waves from the piezoelectric vibrator 1 are transmitted by the liquid retaining material 2.
The vibration plate 2 is suppressed from propagating through the liquid and dissipating, and the diaphragm 2 is efficiently vibrated. The elastic vibration generated in the vibrating portion 7 effectively functions for atomizing the liquid. Along 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 is subjected to the throttling action by the holes 8 and flows out to the upper surface of the vibrating portion 7. I do. As a result, the liquid that has flowed out of the hole 8 is efficiently atomized by the throttle action and the bending vibration of the vibrating section 7. According to the ultrasonic atomizing device of the present embodiment, the frequency is 114.V when the applied voltage is 9.8V.
The amount of atomization becomes maximum at 6kHz, and the power consumption at that time is 2
94 mW, current is 30 mA. The power consumption of the entire apparatus 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 section 7 and the amount of atomization when the length of the vibrating section 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. Further, FIG. 8 is a characteristic diagram showing the relationship between the length of the vibrating portion 7 and the height of ejection of mist. However, the height at this time is a value obtained by converting what is ejected in an oblique direction into a value vertically upward. When the vibrating part 7 has a length of 17 mm, the fog height is 1
The maximum value of 12 cm was reached.

FIG. 9 is a characteristic diagram showing the relationship between the phase and frequency of the impedance of the piezoelectric vibrator 1 of the embodiment shown in FIG. 1, and FIG. 10 shows the piezoelectric vibrator 1 and the diaphragm 2 of the embodiment shown in FIG. FIG. 5 is a characteristic diagram showing a 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. fa represents an intermediate value of two resonance frequencies among 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 amount of atomization is maximized, and f0 substantially coincides with 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 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 this figure), and FIG. It is a top view when the sound wave generation element 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 vibrator 60 has a columnar piezoelectric ceramic 61 having a hole penetrated in parallel with the polarization axis with both ends perpendicular to the polarization axis as end faces, and the material of the piezoelectric ceramic 61 is TDK72.
Material A (product name) has a diameter of 24 mm and a thickness of 6 mm, and the through-hole is also cylindrical, and its diameter is 12 mm. TDK7
The 2A material has a large electromechanical coupling coefficient and is used in the embodiment here. Au electrodes 6 are provided on both end surfaces, respectively.
2 and an Au electrode 63 are formed. Au electrode 62
Is connected to a terminal P, and a terminal Q is mounted to the Au electrode 63.

A disk-shaped diaphragm 70 is attached to the lower end surface of the piezoelectric vibrator 60 at a position covering the opening of the through hole. The diaphragm 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 to the piezoelectric vibrator 60, 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. Diameter of diaphragm 70 is 14m
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 the thickness direction, and the size and shape of the holes are the same as those of the holes 8 in FIGS. 3 and 4. The composite including the piezoelectric vibrator 60 and the vibrating plate 70 is attached to the support plate 23 in such a manner that the vibrating part 71 is in contact with the liquid retaining material 22.

When the ultrasonic atomizing device shown in FIG. 6 is provided with the ultrasonic generating element shown in FIGS. 11 and 12 instead of the ultrasonic generating element shown in FIG. 1, a frequency substantially equal to the resonance frequency of the complex is changed. The AC signal that it has is applied to the piezoelectric vibrator 60 via the terminals P and Q. The piezoelectric vibrator 60 is excited, and the vibrating part 71 surrounded by the fixing part 72 is
And vibrate together. The combined vibration of the vibrating portion 71 effectively functions to atomize the liquid.

FIG. 13 is a characteristic diagram 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 type II has the same dimensions as the type II, 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 atomization amount 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 source 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 decreases while maintaining the characteristics of the II type, but it is effective for generating extremely fine mist. confirmed.

As a liquid supply means, in addition to the present embodiment, when a liquid is dropped on the vibration plate 2 or the vibration plate 70, or on the lower surface of the vibration plate 2 or the vibration plate 70 using a liquid supply tube. Even when the liquid was supplied, the same atomization effect as in this example was observed.

[0036]

According to the ultrasonic wave generating element of the present invention, as the piezoelectric vibrator, a simple structure including a piezoelectric ceramic and electrodes formed on both surfaces perpendicular to the thickness direction of the piezoelectric ceramic is adopted. Thereby, the element can be downsized. Furthermore, the liquid supplied to the diaphragm is efficiently atomized by the effect of the number of holes provided in the diaphragm, and the atomized mist particles are excellent in fineness and uniformity, with low power consumption. Can be driven.

By adopting a structure in which one opening area of the numerous holes provided in the vibrating portion and the other opening area are different, the fineness and uniformity of the particles of the fog can be further promoted.

By adopting a structure in which the vibrating plate is integrally connected and fixed to at least one surface having the electrodes of the piezoelectric vibrator, the vibrating part vibrates with the fixed part as a fixed end, so that a strong elastic vibration is generated. The liquid supplied to the vibrating section in the state of (1) is atomized vertically upward. Due to the synergistic effect of the vibration of the vibrating part and the function of the holes provided in the vibrating part, the atomization action of the liquid is promoted, the amount of generated fog increases, and the particle diameter becomes minute and uniform.

2 in a composite of a piezoelectric vibrator and a diaphragm
A structure in which the intermediate value of the two resonance frequencies is substantially equal to the resonance frequency of the piezoelectric vibrator alone, and a rectangular plate-like structure in which the dimension ratio between the length and the width is close to 1 and not equal to 1 are used as the piezoelectric vibrator. As a result, the combined vibration of the composite body of the piezoelectric vibrator and the diaphragm is enhanced, so that the amount of fog generated further increases.

By adopting a rectangular prismatic structure in which the dimensional ratio of thickness to width is close to 1 and not equal to 1 as the piezoelectric vibrator, the combined vibration of the composite of the piezoelectric vibrator and the diaphragm is enhanced. Therefore, the amount of fog generated further increases.
In addition, by providing two electrodes that are insulated from each other on one surface perpendicular to the thickness direction of the piezoelectric ceramic, one electrode can be used as an electrode for a self-excited power supply, so that stability and efficiency are improved. It is possible to provide an atomizing device that can be driven with low power consumption.

As the piezoelectric ceramic, a columnar structure having a through-hole penetrated in parallel with the polarization axis of the piezoelectric ceramic is employed. By adopting the structure provided substantially parallel to the vertical end surface, the vibration of the piezoelectric vibrator vibrates the vibrating plate efficiently, so that the atomization efficiency of the liquid supplied to the vibrating plate can be increased. The use of a plurality of diaphragms can further improve the fineness of the fog particles. By adopting a structure in which the vibrating plate is integrally connected and fixed to the inside of the through hole of the piezoelectric vibrator and to the position covering the opening, the vibrating part vibrates integrally with the piezoelectric vibrator. The liquid in contact with the vibrating portion in the vibrating state is atomized vertically upward. Due to the synergistic effect of the action of the hole provided in the vibrating part and the vibration of the vibrating part, the atomizing action of the liquid is promoted, the amount of generated fog increases, and the particle diameter becomes uniform.

A structure in which one of the resonance frequencies of the composite of the piezoelectric vibrator and the diaphragm is substantially equal to one of the resonance frequencies of the single piezoelectric vibrator, and the polarization axis of the piezoelectric vibrator is By adopting a rectangular or annular structure in which the ratio of the length in the direction and the shortest distance between the outer edge and the inner edge of the end face is approximately 1, the coupling vibration of the composite of the piezoelectric vibrator and the diaphragm is enhanced. Therefore, the atomization efficiency can be further increased.

When the applied voltage is increased, the combined vibration of the composite of the piezoelectric vibrator and the vibration plate is increased, so that the atomization amount is also increased. Therefore, if the voltage is changed according to the purpose, the atomization amount is increased. You can change it freely.

[Brief description of the drawings]

FIG. 1 is a side view showing one embodiment of an ultrasonic wave generating element of the present invention.

FIG. 2 is a plan view of the ultrasonic generator of FIG. 1;

FIG. 3 is a partially enlarged plan view of a vibrating section 7 of FIG. 2;

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

FIG. 5 is a perspective view showing one embodiment of the ultrasonic wave generating element of the present invention.

FIG. 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 a vibration unit 7 in the ultrasonic generator shown in FIG.
FIG. 6 is a characteristic diagram showing a relationship between the length of the vibrating section 7 and the amount of atomization when the length of the vibrating portion 7 is changed.

8 is a diagram showing a vibration unit 7 in the ultrasonic wave generating element shown in FIG.
FIG. 4 is a characteristic diagram showing a relationship between the length of the mist and the height of the mist ejection.

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

FIG. 10 is a characteristic diagram showing the relationship between impedance phase and frequency for the 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 vibrating plate 70 (not shown in FIG. 11).

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

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 piezoelectric vibrator 2 diaphragm 3 piezoelectric ceramic 4 electrode 5 electrode 6 fixed part 7 vibrating part 8 hole 11 piezoelectric vibrator 12 piezoelectric ceramic 13 electrode 14 electrode 15 electrode 16 vibrating plate 17 vibrating part 18 fixing part 21 storage chamber 22 storage Liquid material 23 Support base 60 Piezoelectric vibrator 61 Piezoelectric ceramics 62 Electrode 63 Electrode 70 Vibration plate 71 Vibrating part 72 Fixed part

Claims (9)

(57) [Claims] 1. An ultrasonic wave generating element comprising a piezoelectric vibrator and a vibrating plate fixed to the vibrating plate, wherein the vibrating plate is provided with a large number of holes penetrating in the thickness direction thereof, and the piezoelectric vibrator is a columnar piezoelectric element. A porcelain, and electrodes formed on both end surfaces perpendicular to the thickness direction of the piezoelectric ceramic, wherein one opening area and another opening area of the diaphragm in the hole are different. Sound wave generator. 2. The piezoelectric vibrating plate is integrally and continuously fixed on at least one end face having electrodes of the piezoelectric vibrator, and the piezoelectric vibrating plate extends outward from the piezoelectric vibrator. The ultrasonic generating device according to claim 1, further comprising a vibrating portion projecting substantially parallel to an end face, wherein the hole is provided in the vibrating portion. 3. The resonance frequency of the piezoelectric vibrator is substantially equal to an intermediate value between two resonance frequencies of a composite body of the piezoelectric vibrator and the vibration plate. Ultrasonic generator. 4. The ultrasonic generating element according to claim 3, wherein the piezoelectric vibrator is a rectangular plate whose dimensional ratio between length and width is close to 1 and not equal to 1. 5. The ultrasonic wave generating element according to claim 3, wherein the piezoelectric vibrator is a rectangular prism having a thickness-width dimension ratio close to 1 and not equal to 1. 6. The ultrasonic wave generating element according to claim 5, wherein the electrode formed on the one end face is divided into two parts which are insulated from each other. 7. The piezoelectric ceramic has a through hole penetrating in parallel with a polarization axis of the piezoelectric ceramic, and the vibrating plate has the polarization at a position covering an opening of the through hole or inside the through hole. A portion which is provided in at least one place substantially parallel to the end face perpendicular to the axis, the peripheral edge of the vibrating plate is fixed to the piezoelectric vibrator, and which is surrounded by a fixed portion fixed to the piezoelectric vibrator. The ultrasonic wave generating element according to claim 1, wherein the vibrating plate forms a vibrating part, and the hole is provided in the vibrating part. 8. One of the resonance frequencies of the piezoelectric vibrator.
8. The method according to claim 7, wherein one of the resonance frequencies is substantially equal to one of the resonance frequencies of the composite of the piezoelectric vibrator and the vibration plate.
The ultrasonic wave generating element according to 1. 9. The piezoelectric vibrator is rectangular or annular, and the ratio of the length of the piezoelectric vibrator in the direction of the polarization axis to the shortest distance between the outer edge and the inner edge of the end face is substantially equal to 1. The ultrasonic wave generating element according to claim 7, which is characterized in that: