JP7599098B2 - Atomization device - Google Patents

Description

The present disclosure relates to a nebulization device.

Conventionally, there are atomization devices that generate mist for use in sterilization, deodorization, etc. (See, for example, Patent Document 1). Patent Document 1 discloses a device that atomizes liquid using an ultrasonic generator.

Special Publication No. 6-507836

When ultrasonic vibrations emitted from an ultrasonic transducer are applied to a liquid, a liquid column rises from the surface of the liquid that has received the vibration energy. Microscopic waves called capillary waves are generated on the surface of the liquid column, and it is thought that when the amplitude of the waves exceeds a critical point, the top of the wave breaks off, generating mist.

Here, when atomizing a liquid using ultrasonic vibrations, the higher the frequency of the vibrations applied to the liquid, the smaller the size of the mist generated from the liquid column.

For example, from the perspective of effectiveness, mist used for sterilization, deodorization, etc. is required to have a particle size on the order of nanometers to micrometers. If the mist is finely divided and sprayed into space, the probability of collision with bacteria, foul-smelling gases, etc. present in the space and the diffusion of the mist can be improved.

However, in order to increase the natural frequency (fundamental resonant frequency) at which an ultrasonic transducer operates, it is necessary to reduce the thickness of the ultrasonic transducer. Therefore, the higher the fundamental resonant frequency at which an ultrasonic transducer operates, the more difficult it becomes to manufacture the ultrasonic transducer. This makes it difficult to reduce the size of the mist when atomizing liquids using an ultrasonic transducer.

It is also known that if the frequency of vibration applied to the liquid is increased, the amount of mist generated decreases significantly.

The present disclosure provides a nebulization device that can control the particle size of the mist to an appropriate size and suppress a decrease in the amount of mist generated.

The atomization device according to one aspect of the present disclosure comprises an ultrasonic vibrator having multiple resonance points, a drive control unit that causes the ultrasonic vibrator to oscillate, and a member having a through hole through which the sound waves emitted by the ultrasonic vibrator and the liquid propagating the sound waves pass and which has an outlet for ejecting the liquid in a columnar form, and the drive control unit causes the ultrasonic vibrator to oscillate at a higher resonance frequency than the first resonance frequency of the ultrasonic vibrator.

According to the present disclosure, it is possible to provide a nebulization device that can control the particle size of the mist to an appropriate size and suppress a decrease in the amount of mist generated.

FIG. 1 is a schematic cross-sectional view showing the configuration of the atomization device according to the first embodiment. FIG. 2 is a perspective view showing members included in the atomization device according to the first embodiment. FIG. 3 is a diagram showing an example of the impedance characteristics of an ultrasonic transducer. FIG. 4 is a diagram showing the particle size of the mist relative to the vibration frequency applied to the liquid. FIG. 5 is a schematic cross-sectional view showing a configuration of a spray device according to a modified example of the first embodiment. FIG. 6 is a schematic cross-sectional view showing the configuration of the atomization device according to the second embodiment. FIG. 7 is a diagram for explaining the relationship between the nozzle diameter and the beam diameter. FIG. 8 is a schematic cross-sectional view showing the configuration of the atomization device according to the third embodiment.

Below, the embodiments of the present disclosure are described in detail with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement and connection of the components, steps, order of steps, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

In addition, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scale and the like do not necessarily match in each figure. In addition, in each figure, substantially the same configuration is given the same symbol, and duplicate explanations may be omitted or simplified.

In addition, in this specification and the drawings, the X-axis, Y-axis, and Z-axis refer to the three axes of a three-dimensional Cartesian coordinate system. In each embodiment, the Z-axis direction is the vertical direction, and the direction perpendicular to the Z-axis (parallel to the XY plane) is the horizontal direction. Note that in each embodiment, the positive direction of the Z-axis is described as being vertically upward.

(Embodiment 1)
[composition]
FIG. 1 is a schematic cross-sectional view showing the configuration of the atomizing device 100 according to the first embodiment. FIG. 2 is a perspective view showing a member 130 included in the atomizing device 100 according to the first embodiment. In FIG. 1, the control unit 150 is illustrated as a functional block. The control unit 150 is controllably connected to the ultrasonic transducer 120 and the supply unit 140 by a control line or the like, and controls each device. The control unit 150 is realized, for example, by a microcomputer (microcontroller) or the like, and is disposed inside an outer shell housing (not shown) of the atomizing device 100. The control unit 150 may be attached, for example, to the outside of the outer shell housing (not shown).

The mist generating device 100 is a mist generating device that turns (atoms) the liquid 200 into mist and generates the mist 220 that has buoyancy and floats in the atmosphere. For example, the mist generating device 100 uses sound waves (hereinafter referred to as beam 230) emitted from the ultrasonic vibrator 120 when the ultrasonic vibrator 120 vibrates ultrasonically to eject a liquid column 210 made of the liquid 200 from a nozzle 132 provided (formed) in a member 130. Countless mist particles 220 are emitted from the surface of the liquid column 210 ejected from the nozzle 132. In this way, the mist generating device 100 generates the mist 220.

The mist 220 is one of multiple liquid particles formed by misting the liquid 200. The misting device 100 is used, for example, in a humidifier, a deodorizer, or a sterilizer.

The liquid 200 is water, but any liquid such as oil may be used. The liquid 200 may also contain a fragrance component or a sterilizing component. For example, if the liquid 200 contains a fragrance component, the mist generation device 100 is a fragrance generator that generates a mist 220 containing the fragrance component. Alternatively, for example, if the liquid 200 contains a sterilizing component such as hypochlorous acid, the mist generation device 100 is a sterilizing device.

The mist 220 is, for example, fine liquid particles having a diameter on the order of micrometers, and has the ability to float in the air. For example, the number-average diameter of the mist 220 is about several μm. For example, the number-average diameter of the mist 220 is 1.5 μm or less.

The nebulization device 100 comprises a container 110, an ultrasonic vibrator 120, a member 130, a supply unit 140, and a control unit 150.

The container 110 is a container that contains the liquid 200 and is open at the top. In this embodiment, the container 110 supports the ultrasonic transducer 120 and the member 130. The material used for the container 110 is, for example, a resin material, but is not particularly limited. The container 110 is provided with, for example, a liquid phase section 111 in which the liquid 200 is contained, and a gas phase section 112 in which the liquid 200 is not contained.

The ultrasonic vibrator 120 is a vibrator for applying ultrasonic vibrations to the liquid 200. The ultrasonic vibrator 120 has multiple resonance points (resonance frequencies). Specifically, in addition to the fundamental resonance frequency (first-order resonance frequency), the ultrasonic vibrator 120 has a resonance point that vibrates at a higher-order resonance frequency than the fundamental resonance frequency.

The ultrasonic transducer 120 vibrates ultrasonically when a voltage is applied to the control unit 150 (more specifically, the drive control unit 152). The ultrasonic transducer 120 is, for example, a piezoelectric element. In this embodiment, the ultrasonic transducer 120 is arranged at the bottom of the container 110 so as to vibrate in the Z-axis direction to emit a beam 230 in the positive direction of the Z-axis. A member 130 is arranged in the direction in which the beam 230 is emitted from the ultrasonic transducer 120 (in this embodiment, on the positive Z-axis side of the ultrasonic transducer 120).

The member 130 is a porous body provided with a through hole 131 having a nozzle 132 through which the beam 230 emitted by the ultrasonic transducer 120 and the liquid 200 propagating the beam 230 pass and which ejects the liquid 200 in a columnar shape. The through hole 131 is provided in the member 130 so as to extend in the direction in which the beam 230 emitted by the ultrasonic transducer 120 propagates. The nozzle 132 ejects a liquid column 210 made of the liquid 200 propagating the beam 230 emitted by the ultrasonic transducer 120 that has passed through the through hole 131. In this embodiment, the member 130 is cylindrical, more specifically, angular (horn-shaped) having the through hole 131 and the nozzle 132 in the center.

The through hole 131 has a gradually narrowing diameter toward the side where the ultrasonic transducer 120 emits the beam 230 (the positive Z-axis direction in this embodiment). In this way, the inner wall 134 (also called the inner surface or wall portion) of the member 130 is, for example, an inclined portion that is a tapered surface inclined with respect to the direction where the ultrasonic transducer 120 emits the beam 230 (the Z-axis direction in this embodiment). As a result, the beam 230 is reflected by the inner surface of the member 130 and focused (collected) near the nozzle 132.

The nozzle 132 is an opening for ejecting liquid 200 to form a liquid column 210.

The ratio between the lower hole diameter of the through-hole 131 (the opening on the side where the liquid 200 is introduced into the through-hole 131) and the upper hole diameter of the through-hole 131 (i.e., the hole diameter of the ejection port 132) is not particularly limited. When the hole diameter of the ejection port 132 is about 1 mm, the width of the liquid column 210 (the length in the direction perpendicular to the extension direction of the liquid column 210) is about 1 mm.

In addition, the shape of the opening of the through hole 131 and the nozzle 132 is, for example, circular, but may also be square, rectangular, elliptical, etc.

The end 133 (more specifically, the end surface) of the member 130 on the side where the nozzle 132 is provided is, for example, water-repellent. In other words, the end 133 around the nozzle 132 in the member 130 is water-repellent. For example, a material such as a fluoride having a water-repellent film may be provided on the end 133, or the surface of the end 133 of the member 130 may be processed to have water-repellency. Alternatively, the member 130 may be realized with a material such as a fluoride having water-repellency. In this way, the end 133 located around the nozzle 132 in the member 130 is water-repellent. In other words, the member 130 has, for example, at least the end 133 on the side where the nozzle 132 is formed in the member 130 is water-repellent.

Also, for example, the member 130 is arranged such that the end 133 located around the nozzle 132 is located in the gas phase section 112. In other words, the end 133 of the member 130 on the side where the nozzle 132 is formed is located in the gas phase section 112 of the container 110. For example, the supply section 140 described below supplies the liquid 200 to the container 110 so that the end 133 is not immersed in the liquid 200. Alternatively, the member 130 may be arranged in the container 110 such that the end 133 is located above an opening located above the container 110.

The material used for member 130 is not particularly limited. For example, the material used for member 130 is a resin material. Note that the material used for member 130 may be a reflective material that reflects beam 230.

The supply unit 140 is a water supply unit that supplies the liquid 200 to the container 110. The supply unit 140 includes, for example, an electromagnetic valve for switching between supplying and not supplying the liquid 200 to the container 110, and a pipe through which the liquid 200 passes. The supply unit 140 (more specifically, the electromagnetic valve included in the supply unit 140) is controlled by, for example, the control unit 150 (more specifically, the supply control unit 151) to switch between supply and non-supply as described above. The supply unit 140 is connected to, for example, a tank (not shown) in which the liquid 200 that is the source of the mist 220 sprayed from the atomization device 100 is stored, and the liquid 200 supplied from the tank is supplied to the container 110 in a manner that allows switching between supply and non-supply under the control of the supply control unit 151.

The control unit 150 is a control device that controls the overall operation of the atomization device 100. Specifically, the control unit 150 controls the operation of the ultrasonic vibrator 120 and the supply unit 140.

The control unit 150 includes a supply control unit 151 and a drive control unit 152.

The supply control unit 151 is a processing unit for controlling the operation of the supply unit 140. For example, the supply control unit 151 controls an electromagnetic valve provided in the supply unit 140 to cause the supply unit 140 to supply the liquid 200 to the container 110. In order to control the amount of liquid 200 supplied to the liquid 200 by the supply unit 140, the atomization device 100 may be provided with a measuring device such as a timekeeping unit such as an RTC (Real Time Clock) for measuring time, a water level sensor for measuring the amount of liquid 200 contained in the container 110, or a flow meter for measuring the amount of liquid 200 flowing through the supply unit 140. The supply control unit 151 may control the supply unit 140 based on the measurement result of the measuring device. For example, the supply control unit 151 causes the supply unit 140 to supply the liquid 200 to the container 110 so that the end 133 is not immersed in the liquid 200.

The drive control unit 152 is a processing unit that causes the ultrasonic transducer 120 to oscillate (drive). Specifically, the drive control unit 152 causes the ultrasonic transducer 120 to oscillate at a higher resonant frequency than the first resonant frequency of the ultrasonic transducer 120. For example, the drive control unit 152 controls the timing of applying a voltage to the ultrasonic transducer 120, the magnitude of the voltage, the frequency, etc.

Figure 3 is a diagram showing an example of the impedance characteristics of the ultrasonic transducer 120. For example, the horizontal axis of the graph shown in Figure 3 is the frequency of the voltage (e.g., AC voltage) applied to the ultrasonic transducer 120, and the vertical axis is the impedance of the ultrasonic transducer 120 at the frequency of the applied voltage.

As shown in FIG. 3, for example, the first-order resonant frequency of the ultrasonic transducer 120 is 2.5 MHz. Also, for example, the third-order resonant frequency of the ultrasonic transducer 120 is 8.2 MHz. Also, for example, the fifth-order resonant frequency of the ultrasonic transducer 120 is 13.7 MHz. In this way, the ultrasonic transducer 120 has multiple resonant points.

Figure 4 shows the particle size of mist 220 versus the vibration frequency applied to liquid 200.

Generally, the particle size of the mist 220 relative to the vibration frequency applied to the liquid 200 is expressed by Lang's equation shown in the following equation (1).

In the above formula (1), _dp is the particle diameter of the mist 220, k is a proportionality coefficient obtained experimentally, ρ is the density of the liquid 200, f is the vibration frequency applied to the liquid 200, and σ is the surface tension of the liquid 200. The graph shown in Fig. 4 shows the particle diameter of the mist 220 versus the frequency applied to the liquid 200 when the Lang formula is used in a case where the liquid 200 is water.

As shown in Figure 4, for example, in order to make the particle size of the mist 220 1.5 μm or less, it is necessary to apply vibrations of a frequency of about 5 MHz to the liquid 200. Therefore, for example, the drive control unit 152 causes the ultrasonic transducer 120 to oscillate at a high-order resonant frequency exceeding 5 MHz.

As a result, the drive control unit 152 can control the ultrasonic vibrator 120 to generate a liquid column 210 and generate mist 220 having a particle size of 1.5 μm or less from the liquid column 210.

Also, for example, to generate mist 220 with a particle size of 1 μm, it is necessary to apply vibrations of about 8.5 MHz to the liquid 200. Therefore, the drive control unit 152 causes the ultrasonic transducer 120 to oscillate at a higher resonant frequency (third in this embodiment) than the first resonant frequency of the ultrasonic transducer 120. Specifically, the drive control unit 152 applies a voltage of a higher resonant frequency to the ultrasonic transducer 120, which causes the ultrasonic transducer 120 to vibrate in the direction of arrangement of the ultrasonic transducer 120 and the member 130, thereby vibrating the ultrasonic transducer 120 at the higher resonant frequency.

In this way, the drive control unit 152 controls the ultrasonic vibrator 120 to generate a liquid column 210 and generate mist 220 with a particle size of approximately 1 μm from the liquid column 210.

The control unit 150 is realized, for example, by a microcontroller or the like. Specifically, the control unit 150 is realized by a communication interface for communicating with the ultrasonic transducer 120 and the supply unit 140, a non-volatile memory in which a program is stored, a volatile memory which is a temporary storage area for executing the program, an input/output port, a processor for executing the program, and the like. The control unit 150 may be realized by a dedicated electronic circuit for executing each operation. The control unit 150 may also include, for example, a boost power supply circuit including a converter or the like. For example, the drive control unit 152 generates a voltage of a high-order resonant frequency of the ultrasonic transducer 120 based on power received from an external power source (not shown), such as a commercial power source, and applies the generated voltage to the ultrasonic transducer 120 to vibrate the ultrasonic transducer 120 at the high-order resonant frequency.

The atomizing device 100 may further include a blower that transports the mist 220 into space. The blower is, for example, a DC (Direct Current) fan or other electric fan. The blower generates an airflow toward the outside of the container 110, thereby transporting the mist 220 emitted from the liquid column 210 in a direction away from the container 110. The position where the blower is disposed may be inside the container 110 or outside the container 110, and is not particularly limited.

[Effects, etc.]
As described above, the atomization device 100 according to the first embodiment includes the ultrasonic transducer 120 having a plurality of resonance points, the drive control unit 152 that causes the ultrasonic transducer 120 to oscillate, and the member 130 provided with the through hole 131 through which the beam 230 emitted by the ultrasonic transducer 120 and the liquid 200 propagating through the beam 230 pass and which has the ejection port 132 for ejecting the liquid 200 in a columnar shape. The drive control unit 152 causes the ultrasonic transducer 120 to oscillate at a higher-order resonance frequency than the first-order resonance frequency of the ultrasonic transducer 120.

According to this, the drive control unit 152 oscillates the ultrasonic vibrator 120 at a higher resonance point among the multiple resonance points that the ultrasonic vibrator 120 has, that is, at a higher resonance frequency. Therefore, the drive control unit 152 can vibrate the ultrasonic vibrator 120 at a frequency required to make the particle size of the mist 220 about 1 μm, for example. In addition, according to the member 130, by appropriately setting the size of the nozzle 132, a liquid column 210 with an appropriate diameter is ejected. If the member 130 is not provided, a liquid column 210 with a large diameter is generated. If the diameter of the liquid column 210 becomes large, the vibration energy per unit volume in the liquid column 210 becomes small. As a result, the amount of mist 220 generated is significantly reduced, or the mist 220 is not emitted from the liquid column 210. Therefore, by making the member 130 eject the liquid column 210 with an appropriate diameter from the nozzle 132, the vibration energy transmitted to the surface of the liquid column 210 is increased. This suppresses a decrease in the amount of mist 220 generated. From the above, according to the atomization device 100, it is possible to control the particle size of the mist 220 to an appropriate size, and also to suppress a decrease in the amount of mist 220 generated.

For example, the drive control unit 152 causes the ultrasonic transducer 120 to oscillate at a high-order resonant frequency exceeding 5 MHz.

According to this, for example, if the liquid 200 is water or an aqueous solution, the particle size of the mist 220 can be reduced to about 1 μm as shown in Figure 4. Therefore, for example, compared to when the particle size of the mist 220 is 10 μm or more, the diffusibility of the mist 220 can be improved, and the probability of collision with bacteria, odorous gases, etc. present in the space can be improved.

For example, the atomization device 100 further includes a container 110 having a liquid phase section 111 in which the liquid 200 is contained and a gas phase section 112 in which the liquid 200 is not contained. For example, the member 130 is arranged such that an end 133 located around the nozzle 132 is located in the gas phase section 112.

This prevents the liquid column 210 from coming into contact with the liquid 200 contained in the container 110 immediately after being ejected from the nozzle 132, making it easier to set the diameter of the liquid column 210 to an appropriate size.

For example, the end 133 located around the nozzle 132 in the member 130 has water repellency.

This makes it possible to prevent the liquid 200 from adhering to the end 133 even if the atomizing device 100 continues to generate the mist 220. If the liquid 200 adheres (wets) to the end 133, the diameter of the liquid column 210 may increase, or the generation of the liquid column 210 may become unstable. This may result in a decrease in the amount of mist 220 generated. Therefore, by making the end 133 water-repellent, the diameter of the liquid column 210 can be stabilized, and the decrease in the amount of mist 220 generated can be further prevented.

[Modification]
Next, a modified example of the atomization device according to the embodiment 1 will be described. In the modified example described below, differences from the atomization device 100 according to the embodiment 1 will be mainly described. In the description of the modified example, the same reference numerals will be used for the substantially same configuration as the atomization device 100 according to the embodiment 1, and the description may be partially simplified or omitted.

Figure 5 is a schematic cross-sectional view showing the configuration of a nebulization device 100a relating to a modified example of embodiment 1.

The nebulization device 100a comprises a container 110, an ultrasonic vibrator 120, a member 130, a supply unit 140, and a control unit 150.

In the atomization device 100a, unlike the atomization device 100, the member 130 is inclined. Specifically, the member 130 is arranged in the container 110 so that the hole axis of the ejection port 132 (in this modified example, the extension direction of the through hole 131, an axis parallel to the hole axis of the through hole 131) intersects the vertical direction (in this embodiment, the Z-axis direction). As a result, the extension direction of the liquid column 210 ejected from the ejection port 132 intersects the vertical direction. In other words, the ejection port 132 is provided in the member 130 so that the extension direction of the liquid column 210, which is the columnar liquid 200 ejected from the ejection port 132, intersects the vertical direction. In other words, the ejection port 132 is provided in the member 130 so that the extension direction of the liquid column 210, which is the columnar liquid 200 ejected from the ejection port 132, intersects the vertical direction.

This makes it difficult for the liquid column 210 to be subjected to its own weight. For example, if the extension direction of the liquid column 210 is parallel to the vertical direction, the weight of the upper part of the liquid column 210 is added to the lower part of the liquid column 210. Therefore, if the extension direction of the liquid column 210 is parallel to the vertical direction, the liquid column 210 is difficult to form due to the weight of the liquid column 210. In this way, the liquid column 210 that has lost momentum immediately after being ejected from the ejection port 132 returns to the vicinity of the original ejection port 132 due to its own weight, falling, etc., so that the diameter of the liquid column 210 becomes unstable and the amount of atomization in the liquid column 210 decreases. Therefore, by providing the ejection port 132 in the member 130 so that the extension direction of the liquid column 210 intersects the vertical direction, the weight of the liquid column 210 is difficult to be applied to the liquid column 210. This makes it easier to form the liquid column 210.

In this modified example, the member 130 is arranged in the container 110 at an angle relative to the atomization device 100 according to embodiment 1, but the nozzle 132 may be provided in the member 130 such that the extension direction of the liquid column 210 intersects with the vertical direction. For example, the member may have a through hole whose hole axis is parallel to the vertical direction, and a nozzle that communicates with the through hole and whose hole axis intersects with the vertical direction. Specifically, the member may be formed such that the hole axis of the nozzle 132 intersects with the hole axis of the through hole 131 in the attitude of the member 130 according to embodiment 1.

(Embodiment 2)
Next, the atomization device according to the embodiment 2 will be described. In the following description of the embodiment 2, differences from the atomization device 100 according to the embodiment 1 will be mainly described. In the description of the embodiment 2, the configurations substantially similar to those of the atomization device 100 according to the embodiment 1 will be denoted by the same reference numerals, and the description may be partially simplified or omitted.

[composition]
FIG. 6 is a schematic cross-sectional view showing the configuration of an atomization device 101 according to the second embodiment.

The nebulization device 101 includes a container 110, an ultrasonic vibrator 120, a member 130, a supply unit 140, a control unit 150, and a sound collection unit 160. In this way, the nebulization device 101 includes the configuration of the nebulization device 100, and further includes the sound collection unit 160.

The sound collection unit 160 is an acoustic lens that receives the sound waves (beam 230) emitted by the ultrasonic transducer 120 and focuses the incident beam 230 through the through hole 131 to a predetermined focal point 240. In other words, the predetermined focal point 240 is the focal point of the sound collection unit 160.

Here, the predetermined focus 240 is (i) located at the nozzle 132, or (ii) located farther away than the nozzle 132 from the sound collection section 160.

In this embodiment, the sound collecting unit 160 is a transparent acoustic lens located between the ultrasonic transducer 120 and the member 130, which transmits and emits the incident beam 230. The exit surface 170 of the sound collecting unit 160, which emits the beam 230, is concave. The member 130 is disposed at a position opposite to the exit surface 170.

In this embodiment, the incident surface of the sound collecting section 160 where the beam 230 is incident is arranged in contact with the ultrasonic transducer 120. This makes it possible to suppress attenuation due to interference of the beam 230 between the ultrasonic transducer 120 and the sound collecting section 160, and the generation of fine bubbles caused by cavitation.

The size of the sound collecting section 160 may be any size. For example, when viewed along the direction of travel of the beam 230 emitted from the ultrasonic transducer 120, the sound collecting section 160 covers the ultrasonic transducer 120 and is the same size as or larger than the ultrasonic transducer 120.

Figure 7 is a diagram illustrating the relationship between the diameter W1 of the nozzle 132 and the beam diameter W2.

The diameter W1 of the nozzle 132 is larger than the beam diameter W2 of the beam 230 focused on the sound collecting unit 160. Specifically, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 at the predetermined focal point 240 of the beam 230 focused on the sound collecting unit 160. In other words, at the predetermined focal point 240, the beam 230 is focused so that the beam diameter W2 is smaller than the diameter W1 of the nozzle 132. In other words, the sound collecting unit 160 is formed so that the beam diameter W2 at the predetermined focal point 240 of the beam 230 is smaller than the diameter W1 of the nozzle 132. The beam diameter W2 is calculated as W2 = a x λ / D x F. a is a proportionality coefficient that is an arbitrary value, λ is the wavelength of the beam 230, D is the diameter of the ultrasonic transducer 120, and F is the focal length of the sound collecting unit 160.

Also, for example, the diameter W1 of the nozzle 132 is 10 times or less than the beam diameter W2. Specifically, for example, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 and is 10 times or less than the beam diameter W2. More specifically, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 at the predetermined focal point 240 and is 10 times or less than the beam diameter W2.

Also, for example, the member 130 is arranged so that the inner wall 134 of the member 130, in other words, the inner wall 134 forming the through hole 131 in the member 130, is located outside the path of the beam 230 that converges from the surface (i.e., the exit surface 170) that emits the beam 230 in the sound collecting unit 160 to the predetermined focal point 240. In other words, the ultrasonic transducer 120, the member 130, and the sound collecting unit 160 are shaped and arranged so that the beam 230 does not come into contact with the member 130 from the exit surface 170 that emits the beam 230 in the sound collecting unit 160 to the predetermined focal point 240.

For example, the drive control unit 152 applies a voltage of a high-order resonant frequency to the ultrasonic transducer 120, which vibrates the ultrasonic transducer 120 in the direction of alignment of the ultrasonic transducer 120 and the sound collecting unit 160, thereby vibrating the ultrasonic transducer 120 at a high-order resonant frequency. As a result, a beam 230 is emitted from the ultrasonic transducer 120 toward the sound collecting unit 160. The beam 230 emitted from the ultrasonic transducer 120 passes through the sound collecting unit 160 and is emitted so as to be focused at a predetermined focal point 240. The beam 230 emitted from the sound collecting unit 160 passes through the through hole 131 and the nozzle 132 so as not to come into contact with the inner wall 134 of the member 130. As a result, the loss of vibration energy due to reflection on the inner wall 134 of the member 130 is suppressed in the liquid column 210, and the beam 230 collected by the sound collecting unit 160 is transmitted.

The material used for the sound collecting section 160 is not particularly limited as long as it has transparency to the beam 230 (for example, the property of transmitting 70% or more of the beam 230). The material used for the sound collecting section 160 is, for example, a resin material such as polycarbonate.

[Effects, etc.]
As described above, the atomization device 101 according to the second embodiment includes the ultrasonic vibrator 120, the drive control unit 152, and the member 130 provided with the through-hole 131 having the nozzle 132, similar to the atomization device 100 according to the first embodiment. The atomization device 101 further includes a sound collecting unit 160 that receives the beam 230 emitted by the ultrasonic vibrator 120, passes through the through-hole 131, and emits the beam 230 so as to be focused on a predetermined focal point 240. The predetermined focal point 240 is (i) located at the nozzle 132, or (ii) located farther away from the sound collecting unit 160 than the nozzle 132.

According to this, the beam 230 emitted from the ultrasonic transducer 120 is focused at the position where the liquid column 210 is formed. This allows the vibration energy of the beam 230 to be appropriately transmitted to the liquid column 210. This makes it even easier to generate mist 220 from the liquid column 210.

For example, the sound collecting unit 160 is located between the ultrasonic transducer 120 and the member 130, and transmits the incident beam 230 and emits it.

In this way, the sound collecting unit 160 may be realized by a transparent acoustic lens that transmits and focuses the beam 230. In this way, the sound collecting unit 160 can focus the beam 230 with a simple configuration.

Also, for example, the exit surface 170 from which the beam 230 is emitted in the sound collecting section 160 is concave.

Accordingly, even if the sound collecting section 160 is arranged so that the surface of the sound collecting section 160 facing the ultrasonic transducer 120 is perpendicular to the traveling direction of the beam 230, the beam 230 can be focused. In this embodiment, the sound collecting section 160 is arranged so as to be in contact with the ultrasonic transducer 120 so that the surface of the sound collecting section 160 facing the ultrasonic transducer 120 is perpendicular to the traveling direction of the beam 230. This suppresses interference of the beam 230 between the ultrasonic transducer 120 and the sound collecting section 160. Therefore, a decrease in the vibration energy of the beam 230 due to the generation of bubbles due to the interference of the beam 230 is suppressed.

Also, for example, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 of the beam 230 focused on the sound collecting section 160.

This allows the beam 230 to pass through the through hole 131 and the nozzle 132 provided in the member 130 without contacting the member 130. Therefore, the vibration energy of the beam 230 can be transmitted to the liquid column 210 without being reduced by the member 130.

Also, for example, the diameter W1 of the nozzle 132 is less than 10 times the beam diameter W2 of the beam 230 focused on the sound collecting section 160.

The diameter of the liquid column 210 depends on the diameter W1 of the nozzle 132. For example, when the diameter W1 of the nozzle 132 is increased, the diameter of the liquid column 210 also increases. Here, if the diameter W1 of the nozzle 132 is too large compared to the beam diameter W2, the vibrational energy of the beam 230 is not easily transmitted to the liquid column 210 (more specifically, to the surface of the liquid column 210). Therefore, by making the diameter W1 of the nozzle 132 10 times or less the beam diameter W2, the vibrational energy of the beam 230 can be appropriately transmitted to the liquid column 210.

Also, for example, member 130 is positioned so that inner wall 134 of member 130 is located outside the path of beam 230 converging from the surface (exit surface 170) in sound collecting section 160 that emits beam 230 to a predetermined focal point 240.

This allows the beam 230 to pass through the through hole 131 and the nozzle 132 provided in the member 130 without contacting the member 130. Therefore, the vibration energy of the beam 230 can be transmitted to the liquid column 210 without being reduced by the member 130.

(Embodiment 3)
Next, the atomization device according to the embodiment 3 will be described. In the following description of the embodiment 3, the differences from the atomization device 100 according to the embodiment 1 or the atomization device 101 according to the embodiment 2 will be mainly described. In the description of the embodiment 3, the configurations substantially similar to those of the atomization device 100 according to the embodiment 1 or the atomization device 101 according to the embodiment 2 will be denoted by the same reference numerals, and the description may be partially simplified or omitted.

[composition]
FIG. 8 is a schematic cross-sectional view showing the configuration of an atomization device 102 according to the third embodiment.

The nebulizer 102 includes a container 110, an ultrasonic vibrator 120, a member 130, a supply unit 140, a control unit 150, and a sound collector 161. In this way, the nebulizer 102 includes the configuration of the nebulizer 100, and further includes a sound collector 161.

The sound collecting unit 161 is an acoustic lens that receives the sound waves (beam 230) emitted by the ultrasonic transducer 120 and focuses the incident beam 230 through the through hole 131 to a predetermined focal point 240. In other words, the predetermined focal point 240 is the focal point of the sound collecting unit 161.

Here, the predetermined focus 240 is (i) located at the nozzle 132, or (ii) located farther away than the nozzle 132 when viewed from the sound collecting section 161.

In this embodiment, the sound collecting unit 161 is a member (i.e., a reflective acoustic lens) that has reflectivity for the outgoing beam 230 by reflecting the incident beam 230. The reflecting surface 171 in the sound collecting unit 161 that reflects the beam 230 is a parabolic surface (parabolic surface-shaped).

Below, we will explain the relationship between the diameter W1 of the nozzle 132 and the beam diameter W2, referring to Figure 8 as well as Figure 7.

The diameter W1 of the nozzle 132 is larger than the beam diameter W2 of the beam 230 focused on the sound collecting unit 161. Specifically, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 at the predetermined focal point 240 of the beam 230 focused on the sound collecting unit 161. In other words, at the predetermined focal point 240, the beam 230 is focused so that the beam diameter W2 is smaller than the diameter W1 of the nozzle 132. In other words, the sound collecting unit 161 is formed so that the beam diameter W2 at the predetermined focal point 240 of the beam 230 is smaller than the diameter W1 of the nozzle 132. The beam diameter W2 is calculated by W2 = a x λ / D x F. a is a proportionality coefficient that is an arbitrary value, λ is the wavelength of the beam 230, D is the diameter of the ultrasonic transducer 120, and F is the focal length of the sound collecting unit 161.

Also, for example, the diameter W1 of the nozzle 132 is 10 times or less than the beam diameter W2. Specifically, for example, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 and is 10 times or less than the beam diameter W2. More specifically, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 at the predetermined focal point 240 and is 10 times or less than the beam diameter W2.

Also, for example, member 130 is arranged so that inner wall 134 of member 130, in other words, inner wall 134 forming through hole 131 in member 130, is located outside the path of beam 230 that converges from the surface that emits beam 230 in sound collecting section 161 (i.e., reflecting surface 171) to the predetermined focal point 240. In other words, the ultrasonic transducer 120, member 130, and sound collecting section 161 are shaped and arranged so that beam 230 does not come into contact with member 130 from reflecting surface 171 that reflects beam 230 in sound collecting section 161 to the predetermined focal point 240.

For example, the drive control unit 152 applies a voltage of a high-order resonant frequency to the ultrasonic transducer 120, which vibrates the ultrasonic transducer 120 in the direction of alignment of the ultrasonic transducer 120 and the sound collecting unit 161, thereby vibrating the ultrasonic transducer 120 at a high-order resonant frequency. As a result, a beam 230 is emitted from the ultrasonic transducer 120 toward the sound collecting unit 161. The beam 230 emitted from the ultrasonic transducer 120 is reflected by the sound collecting unit 161 and emitted from the sound collecting unit 161 so as to be focused at a predetermined focal point 240. The beam 230 emitted from the sound collecting unit 161 passes through the through hole 131 and the nozzle 132 so as not to come into contact with the inner wall 134 of the member 130. As a result, the loss of vibration energy due to reflection on the inner wall 134 of the member 130 is suppressed, and the beam 230 collected by the sound collecting unit 161 is transmitted to the liquid column 210.

The material used for the sound collecting unit 161 is not particularly limited as long as it has reflectivity to the beam 230 (e.g., the property of reflecting the beam 230 by 90% or more). The material used for the sound collecting unit 161 is, for example, a metallic material such as stainless steel (stainless steel/SUS), but is not particularly limited.

[Effects, etc.]
As described above, the atomization device 102 according to the third embodiment includes the ultrasonic vibrator 120, the drive control unit 152, and the member 130 provided with the through-hole 131 having the nozzle 132, similar to the atomization device 100 according to the first embodiment. The atomization device 102 further includes a sound collecting unit 161 that receives the beam 230 emitted from the ultrasonic vibrator 120 and emits the beam 230 so that the beam 230 passes through the through-hole 131 and is focused on a predetermined focal point 240. The predetermined focal point 240 is (i) located at the nozzle 132, or (ii) located farther away from the sound collecting unit 161 than the nozzle 132.

According to this, the beam 230 emitted from the ultrasonic transducer 120 is focused at the position where the liquid column 210 is formed. This allows the vibration energy of the beam 230 to be appropriately transmitted to the liquid column 210. This makes it even easier to generate mist 220 from the liquid column 210.

For example, the sound collecting unit 161 outputs the incident beam 230 by reflecting it.

In this way, the sound collecting unit 161 may be realized by a reflective acoustic lens that reflects and focuses the beam 230. In this way, the sound collecting unit 161 can focus the beam 230 with a simple configuration.

Also, for example, the reflecting surface 171 that reflects the incident beam 230 in the sound collecting section 161 is a paraboloid.

Accordingly, even if the sound collecting unit 161 is arranged so that the surface of the sound collecting unit 161 facing the ultrasonic transducer 120 is perpendicular to the traveling direction of the beam 230, the beam 230 can be focused. In this embodiment, the sound collecting unit 161 is arranged so as to be in contact with the ultrasonic transducer 120 so that the surface of the sound collecting unit 161 facing the ultrasonic transducer 120 is perpendicular to the traveling direction of the beam 230. This suppresses interference of the beam 230 between the ultrasonic transducer 120 and the sound collecting unit 161. Therefore, a decrease in the vibration energy of the beam 230 due to the generation of bubbles due to the interference of the beam 230 is suppressed.

Also, for example, the diameter W1 of the nozzle 132 is larger than the beam diameter W2 of the beam 230 focused on the sound collecting section 161.

This allows the beam 230 to pass through the through hole 131 and the nozzle 132 provided in the member 130 without contacting the member 130. Therefore, the vibration energy of the beam 230 can be transmitted to the liquid column 210 without being reduced by the member 130.

Furthermore, for example, the diameter W1 of the nozzle 132 is less than 10 times the beam diameter W2 of the beam 230 focused on the sound collecting section 161.

The diameter of the liquid column 210 depends on the diameter W1 of the nozzle 132. For example, when the diameter of the nozzle 132 is increased, the diameter of the liquid column 210 also increases. Here, if the diameter W1 of the nozzle 132 is too large compared to the beam diameter W2, the vibrational energy of the beam 230 is not easily transmitted to the liquid column 210 (more specifically, to the surface of the liquid column 210). Therefore, by making the diameter W1 of the nozzle 132 10 times or less the beam diameter W2, the vibrational energy of the beam 230 can be appropriately transmitted to the liquid column 210.

For example, the member 130 is positioned such that the inner wall 134 of the member 130 is located outside the path of the beam 230 that converges from the surface (reflecting surface 171) that emits the beam 230 in the sound collecting section 161 to the predetermined focal point 240.

This allows the beam 230 to pass through the through hole 131 and the nozzle 132 provided in the member 130 without contacting the member 130. Therefore, the vibration energy of the beam 230 can be transmitted to the liquid column 210 without being reduced by the member 130.

Other Embodiments
Although the atomization device according to the present disclosure has been described based on the above-mentioned embodiments, the present disclosure is not limited to the above-mentioned embodiments.

For example, in each of the above embodiments, the external shape of the member 130 is cylindrical, but is not limited to this. The member 130 only needs to have the through hole 131 and the ejection port 132, and the external shape may be any shape, such as a plate shape.

For example, the liquid 200 may be tap water for humidification or cooling, or may be an aqueous liquid containing hypochlorous acid having a sterilizing effect, or may be an oil-based liquid containing fragrances, etc.

For example, the control unit 150 may further include a clock unit for measuring time such as an RTC. For example, the control unit 150 may generate the mist 220 at a time that is arbitrarily determined in advance.

In addition, for example, as a modified example of the atomization device 101 according to embodiment 2 or the atomization device 102 according to embodiment 3, the member 130 may be tilted as in the atomization device 100a according to the modified example of embodiment 1. Specifically, in the configuration of the atomization device 101 according to embodiment 2 or the atomization device 102 according to embodiment 3, the member 130 may be further disposed in the container 110 so that the hole axis of the nozzle 132 intersects with the vertical direction. This further provides the effect of making it easier to form the liquid column 210.

In addition, in each of the above embodiments, all or part of the components of the control unit 150, such as the supply control unit 151 and the drive control unit 152, may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit, such as a CPU (Central Processing Unit) or a processor, reading and executing a software program recorded on a recording medium, such as a HDD (Hard Disk Drive) or a semiconductor memory.

In addition, the components of the control unit 150 may be configured with one or more electronic circuits. Each of the one or more electronic circuits may be a general-purpose circuit or a dedicated circuit.

The one or more electronic circuits may include, for example, a semiconductor device, an integrated circuit (IC), or a large scale integration (LSI). The IC or LSI may be integrated into one chip or into multiple chips. Here, we refer to it as an IC or an LSI, but depending on the degree of integration, it may be called a system LSI, a very large scale integration (VLSI), or an ultra large scale integration (ULSI). Also, a field programmable gate array (FPGA) that is programmed after the LSI is manufactured can be used for the same purpose.

In addition, the general or specific aspects of the present disclosure may be realized as a system, an apparatus, a method, an integrated circuit, or a computer program. Alternatively, the present disclosure may be realized as a computer-readable non-transitory recording medium, such as an optical disk, a HDD, or a semiconductor memory, on which the computer program is stored. The present disclosure may also be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

In addition, this disclosure also includes forms obtained by applying various modifications to each embodiment that may occur to a person skilled in the art, and forms realized by arbitrarily combining the components and functions of each embodiment without departing from the spirit of this disclosure.

100, 100a, 101, 102 Atomization device 110 Container 111 Liquid phase section 112 Gas phase section 120 Ultrasonic transducer 130 Member 131 Through hole 132 Spout 133 End 134 Inner wall 152 Drive control section 160, 161 Sound collection section 170 Emission surface 171 Reflection surface 200 Liquid 210 Liquid column 220 Mist 230 Beam 240 Predetermined focus W1 Diameter W2 Beam diameter

Claims (13)

An ultrasonic transducer having a plurality of resonance points;
A drive control unit that causes the ultrasonic transducer to oscillate;
a member provided with a through hole through which the sound waves generated by the ultrasonic transducer and a liquid that propagates the sound waves pass and which has an ejection port for ejecting the liquid in a columnar shape;
a sound collecting unit that receives sound waves emitted by the ultrasonic transducer, passes through the through hole, and emits the incident sound waves so as to be focused at a predetermined focal point;
The drive control unit causes the ultrasonic transducer to oscillate at a resonance frequency higher than a first resonance frequency of the ultrasonic transducer ,
The predetermined focus is located farther from the sound collecting unit than the outlet.
Atomization device. The atomization device according to claim 1 , wherein the sound collector is located between the ultrasonic transducer and the member, and transmits and emits incident sound waves. The atomization device according to claim 2 , wherein an emission surface of the sound collecting part from which the sound waves are emitted is concave. The atomization device according to claim 1 , wherein the sound collector emits the incident sound waves by reflecting them. The atomization device according to claim 4 , wherein a reflection surface of the sound collecting part that reflects the incident sound wave is a parabolic surface. The atomization device according to any one of claims 1 to 5 , wherein a diameter of the nozzle is larger than a beam diameter of the sound waves focused on the sound collecting portion. The atomization device according to claim 6 , wherein the diameter of the nozzle is 10 times or less the beam diameter. The atomization device according to any one of claims 1 to 7 , wherein the member is arranged such that an inner wall of the member is positioned outside the path of the sound waves that converge from the surface that emits the sound waves in the sound collecting section to the predetermined focal point. The atomization device according to any one of claims 1 to 8 , wherein the drive control unit causes the ultrasonic transducer to oscillate at a high-order resonance frequency exceeding 5 MHz. The liquid storage device further includes a container having a liquid phase portion in which the liquid is stored and a gas phase portion in which the liquid is not stored,
The atomization device according to any one of claims 1 to 9 , wherein the member is disposed such that an end portion thereof located around the nozzle hole is located in the gas phase portion. The atomization device according to any one of claims 1 to 10 , wherein an end portion of the member located around the nozzle has water repellency. The atomization device according to any one of claims 1 to 11 , wherein the nozzle is provided in the member such that an extension direction of a column of the liquid ejected from the nozzle intersects with a vertical direction. The liquid contains a sterilizing component.
The atomization device according to any one of claims 1 to 12.

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