Ultrasonic nebulizer with acoustic focusing device

Abstract

This disclosure provides an "ultrasonic atomizer with an acoustic focusing device." An atomizer for applying a coating includes a nozzle plate, an actuator, and an acoustic focusing device. The nozzle plate defines at least one orifice. The actuator is configured to oscillate to generate a pressure wave within a fluid, thereby ejecting the fluid from the nozzle plate. The acoustic focusing device focuses the pressure wave toward the orifice.

Description

Technical Field

[0001] This disclosure relates to high-capacity coating equipment, and more specifically to a fluid atomizer with a focusing device. Background Technology

[0002] The descriptions in this section are provided only as background information in connection with this disclosure and may not constitute prior art.

[0003] Applying coatings (e.g., primers, base coats, clear coats, etc.) to motor vehicles (e.g., frames, bodies, panels, etc.) in high-volume production environments involves significant capital costs, not only for coating application and control but also for equipment used to capture overspray. Up to 40% of the coating can leave the applicator, or in other words, up to 40% of the purchased and applied coating is wasted (i.e., a transfer efficiency of approximately 60%). The equipment for capturing overspray in a paint shop involves substantial capital expenditure, including large air handling systems to direct overspray downwards through the spray booth, structures for continuous water flow under the spray booth floor to capture overspray, filtration systems, and treatment. Furthermore, operating the equipment is costly because the airflow through the spray booth must be regulated (flowing at speeds greater than 200,000 cubic feet per minute), water flow must be maintained, compressed air must be supplied, and complex electrostatics must be applied to improve transfer efficiency.

[0004] Using known production equipment, a liquid coating is atomized through a nozzle comprising a rotating bell, which is essentially a rotating disk or bowl-shaped object rotating at approximately 20,000–80,000 revolutions per minute. The liquid is typically ejected from an annular slit on the surface of the rotating disk and propelled towards the edge of the bell by centrifugal force. The liquid then forms a ribbon at the edge of the bell, and subsequently, droplets. Despite the device being used for its intended purpose, various problems arise due to its design. First, the momentum of the liquid coating is predominantly lateral, meaning it moves parallel to the vehicle rather than towards it. To compensate for this motion, shaping air is applied, which redirects the droplets toward the vehicle. Furthermore, electrostatics are used to guide the droplets toward the vehicle. The droplets have a fairly wide size distribution, which can cause appearance issues.

[0005] Ultrasonic atomization is an effective means of generating droplets with a narrow size distribution and droplet momentum perpendicular to the surface of the applicator (e.g., towards a vehicle). However, viscous coatings may require a large amount of energy to be ejected from the small aperture size used for ultrasonic atomization.

[0006] This disclosure addresses these problems associated with traditional high-volume production spray booth operations. Summary of the Invention

[0007] This section provides a general overview of this disclosure and is not a full disclosure of the entire scope or all features of this disclosure.

[0008] In one embodiment, an atomizer for applying a coating includes a nozzle plate, an actuator, and an acoustic focusing device. The nozzle plate defines at least one orifice. The actuator is configured to oscillate the nozzle plate to generate a pressure wave within a fluid, thereby ejecting fluid from the nozzle plate. The acoustic focusing device is configured to focus the pressure wave toward the at least one orifice. In various alternative forms of this disclosure: the acoustic focusing device is an acoustic reflector having a concave side facing the nozzle plate; the focal point of the acoustic focusing device is located at the at least one orifice; the at least one orifice is a plurality of orifices; the acoustic focusing device focuses a pressure wave toward the plurality of orifices; the atomizer further includes a plurality of the acoustic focusing devices, each focusing the pressure wave toward a corresponding orifice among the orifices; the atomizer further includes a plurality of the nozzle plates and a plurality of the actuators, each actuator being configured to oscillate a corresponding nozzle plate among the nozzle plates, wherein the atomizer includes a plurality of acoustic focusing devices, each acoustic focusing device being associated with a corresponding nozzle plate among the nozzle plates; the actuator is integrally formed with the nozzle plate; the actuator is a piezoelectric material.

[0009] In another form, an atomizer for applying a coating includes a nozzle plate, an actuator, and an acoustic focusing device. The nozzle plate defines at least one orifice. The actuator is configured to oscillate fluid to form a pressure wave in the fluid. The acoustic focusing device is disposed between the actuator and the nozzle plate and is configured to focus the pressure wave toward the at least one orifice. In various alternative forms of this disclosure: the acoustic focusing device is an acoustic lens having a concave side facing the at least one aperture; the acoustic focusing device is configured such that the sound velocity through the acoustic focusing device varies along the acoustic focusing device to focus the pressure wave toward the at least one aperture; the acoustic focusing device includes a planar body arranged parallel to the nozzle plate, through which the sound velocity varies to focus the pressure wave toward the at least one aperture; the density of the acoustic focusing device varies along the acoustic focusing device to focus the pressure wave toward the at least one aperture; the at least one aperture is a plurality of apertures; the acoustic focusing device focuses the pressure wave toward the plurality of apertures; the atomizer further includes a plurality of acoustic focusing devices, each focusing the pressure wave toward a corresponding aperture among the apertures; the atomizer further includes a plurality of the nozzle plates and a plurality of the actuators, each actuator being configured to oscillate a corresponding nozzle plate among the nozzle plates, wherein the atomizer includes a plurality of acoustic focusing devices, each acoustic focusing device being associated with a corresponding nozzle plate among the nozzle plates.

[0010] In another embodiment, an atomizer for applying a coating includes a nozzle plate, an actuator, and a reservoir. The nozzle plate defines an orifice. The actuator is spaced apart from the nozzle plate. The reservoir is located between the nozzle plate and the actuator. The actuator is configured to oscillate to form a pressure wave through fluid in the reservoir. The actuator is shaped to focus the pressure wave, such that the pressure wave becomes more focused as it moves closer to the nozzle plate. In one of the various alternative embodiments of this disclosure, the actuator is a piezoelectric element having a curved shape with a focal point toward the nozzle plate.

[0011] Other areas of application will become apparent from the description provided herein. It should be understood that the descriptions and specific examples are intended for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0012] To better understand this disclosure, its various forms will now be described by way of example with reference to the accompanying drawings, in which:

[0013] Figure 1 This is a plan view of an exemplary coating spraying system based on the teachings of this disclosure;

[0014] Figure 2 schematically depicted Figure 1 A plan view of the applicator of a spraying system, the applicator having an array of micro-applicators according to the teachings of this disclosure;

[0015] Figure 3 schematically depicted Figure 2 A portion of the applicator, showing one of the microapplicators in a microapplicator;

[0016] Figure 4 schematically depicted Figure 3 The side sectional view of section 4-4 in the figure shows a nozzle with an acoustic focusing device in accordance with the teachings of this disclosure;

[0017] Figure 5 It schematically depicts something similar to Figure 4 A side sectional view showing the nozzle of an acoustic focusing device with a second structure according to the teachings of this disclosure;

[0018] Figure 6 schematically depicted Figure 5 A portion of the side sectional view;

[0019] Figure 7 It schematically depicts something similar to Figure 4 A side sectional view showing the nozzle of an acoustic focusing device with a third structure according to the teachings of this disclosure;

[0020] Figure 8 It schematically depicts something similar to Figure 4 A side sectional view showing the nozzle of an acoustic focusing device with a fourth structure according to the teachings of this disclosure;

[0021] Figure 9 It schematically depicts something similar to Figure 4 A side sectional view showing the nozzle of an acoustic focusing device with a fifth structure according to the teachings of this disclosure;

[0022] Figure 10 It schematically depicts something similar to Figure 4 A side sectional view showing the nozzle of an acoustic focusing device with a sixth structure according to the teachings of this disclosure;

[0023] Figure 11 It schematically depicts something similar to Figure 4 A side sectional view showing the nozzle of an acoustic focusing device with a seventh structure according to the teachings of this disclosure; and

[0024] Figure 12 It schematically depicts something similar to Figure 4A side sectional view showing the nozzle of an acoustic focusing device with an eighth structure according to the teachings of this disclosure.

[0025] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way. Detailed Implementation

[0026] The following description is merely exemplary in nature and is not intended to limit the scope of this disclosure, its application, or its uses. It should be understood that throughout the drawings, corresponding reference numerals indicate similar or corresponding parts and features. Examples are provided to fully convey the scope of this disclosure to those skilled in the art. Numerous specific details, such as the types of specific components, devices, and methods, are set forth to provide a thorough understanding of variations of this disclosure. It will be apparent to those skilled in the art that specific details are not required, and the examples provided herein may include alternative embodiments and are not intended to limit the scope of this disclosure. In some examples, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.

[0027] This disclosure provides various apparatuses, methods, and systems for controlling the application of coatings to motor vehicles in high-volume environments, reducing overspray and improving coating transfer efficiency. It should be understood that the reference to motor vehicles is merely exemplary, and other objects, such as industrial equipment and appliances, can also be coated in accordance with the teachings of this disclosure. Furthermore, the use of "coating" or "paint" should not be construed as limiting this disclosure, and therefore other materials, such as coatings, primers, sealants, cleaning solvents, etc., should be understood to fall within the scope of this disclosure.

[0028] Typically, the teachings of this disclosure are based on droplet spray generating devices in which a perforated membrane is driven by a piezoelectric transducer. Such devices and variations thereof are described in U.S. Patent Nos. 6,394,363, 7,550,897, 7,977,849, 8,317,299, 8,191,982, 9,156,049, 7,976,135, 9,452,442 and U.S. Publications Nos. 2014 / 0110500, 2016 / 0228902, and 2016 / 0158789, the entire contents of which are incorporated herein by reference.

[0029] Now for reference Figure 1 The diagram schematically depicts a paint spraying system 2 for spraying part P using a robotic arm 4. The robotic arm 4 is coupled to at least one material applicator 10 and a frame 5. It includes a material source 8 (e.g., a paint source) and comprises at least one material M (in... Figure 1 The materials shown are M1, M2, M3, ... M n(Hereinafter referred to as "material M"). In some aspects of this disclosure, at least one material M includes different coating materials, different adhesive materials, different sealing materials, etc. Arm 4 moves according to the xyz coordinates relative to the frame 5, causing the material applicator 10 to move across the surface of part P (not marked). Furthermore, power supply 6 is configured to supply power to arm 4 and frame 5. Arm 4 and frame 5 are configured to supply material M from material source 8 to material applicator 10, such that a coating is applied to the surface of part P.

[0030] refer to Figure 2 The diagram schematically illustrates a material applicator 10a or atomizer according to the teachings of this disclosure. In one form of this disclosure, the material applicator 10a includes an array body 100a or nozzle having an applicator array 102a or sub-nozzle comprising a plurality of micro-applicators 110a. In some aspects of this disclosure, the array body 100a having the applicator array 102a is positioned on a base 140a. In one configuration, the base 140a is supported on the end of an articulated robotic arm 4. Figure 1 In another configuration, the base 140a is supported by a spray bar (not shown), which may be fixed or movable relative to the substrate S in one, two, or three dimensions (e.g., Figure 4 As shown). Each of the micro-appliers 110a includes multiple orifices 112a, with material M ( Figure 4 The material is injected through the orifice 112a, causing the atomized droplets 3 ( Figure 4 As described above, material M( Figure 4 The microappliers are typically liquid materials (e.g., primers, base coats, clear coats, etc.), but may optionally include dispersed solids (such as metal microparticles or other particles) to provide a particular aesthetic appearance. The microappliers 110a can be arranged in any configuration, such as a regular or irregular pattern spanning the array body 100a.

[0031] refer to Figure 3 and Figure 4 Each of the microappliers 110a includes a microapplier plate 114a, an actuator 120a, and an acoustic focusing device 124a. Each microapplier plate 114a defines a plurality of holes 112a extending through it. The actuator 120a may be a transducer, such as a piezoelectric material. The microapplier plate 114a is mechanically communicated with the actuator 120a such that activation of the actuator 120a (e.g., supplying power to the actuator 120a) causes the microapplier plate 114a to vibrate or oscillate, as... Figure 4 The horizontal (z-direction) double-headed arrow in the diagram is schematically depicted.

[0032] In the provided example, the array body 100a includes a material inlet 136a corresponding to each microapplier 110a. The array body 100a includes a rear wall 131a and cylindrical sidewalls 132a. A reservoir 134a for receiving material M is defined between the rear wall 131a and the microapplier plate 114a. In the provided example, at least the rear wall 131a and the sidewalls of the microapplier plate 114a facing the rear wall 131a mate to define the reservoir 134a. In the provided example, the reservoir 134a and the microapplier plate 114a... Figure 2 The other microappliers 110a shown are fluidly connected to similar reservoirs, such that all microappliers 110a share a common fluid chamber. In alternative configurations not specifically shown, the reservoirs of some or all microappliers 110a may be separable from each other.

[0033] Inlet 136a is in fluid communication with reservoir 134a, allowing material M to flow through inlet 136a and into reservoir 134a. In the provided example, actuator 120a is positioned between microapplier plate 114a and sidewall 132a, such that array body 100a supports actuator 120a and actuator 120a supports microapplier plate 114a. For example, actuator 120a may be positioned between outer edge surface 115a of microapplier plate 114a and inner surface of array body 100a. In one configuration, actuator 120a is arranged in an annular shape around microapplier plate 114a. In another configuration not specifically shown, actuator 120a may be integrally formed with microapplier plate 114a, such that powering microapplier plate 114a causes plate 114a to oscillate. In the provided example, the control module 164a is electrically connected to the actuator 120a to supply power to the actuator 120a and control the operation of the actuator 120a.

[0034] In the provided example, the rear wall 131a or a portion thereof has a concave surface facing the microapplier plate 114a to define the acoustic focusing device 124a. In the provided example, the acoustic focusing device 124a is an acoustic reflector or acoustic mirror having a curvature (such as parabolic or spherical) with a focal point near the aperture 112a of the microapplier plate 114a. The focal point may be located within the reservoir 134a, at the microapplier plate 114a, or outside the microapplier plate 114a.

[0035] In operation, material M is supplied to reservoir 134a at very low pressure or no pressure, such that the surface tension of material M prevents it from flowing through the orifices 112a of microapplier plate 114a unless actuator 120a is activated and oscillates. The oscillating microapplier plate 114a generates an initial wave Wa that propagates from the microapplier plate 114a toward the rear wall 131a. The initial wave Wa is reflected by acoustic focusing device 124a as a secondary wave Wa' traveling toward the microapplier plate 114a. In the provided example, the initial wave Wa is typically an unfocused parallel wave. Acoustic focusing device 124a focuses the wave, causing the secondary wave Wa' to be focused or concentrated toward the orifices 112a. This focused wave enables material M to be ejected from the orifices 112a. In the provided example, the secondary wave Wa' impacts the microapplier plate 114a across an area surrounding all orifices 112a but smaller than the entire oscillating microapplier plate 114a. Therefore, wave energy is concentrated at orifice 112a to eject material M.

[0036] In other words, when the actuator 120a is activated and vibrates, material M is ejected through and / or from multiple orifices 112a to provide a flow 5 of atomized droplets 3. The flow 5 of atomized droplets 3 propagates generally parallel to the axis 2' of the micro-applier and forms a coating C on the surface s' of the substrate S. The substrate S can be any suitable workpiece, such as a vehicle part, frame, or body. Figure 4 As schematically depicted, the atomized droplets 3 have a narrow droplet size distribution (e.g., average droplet diameter).

[0037] refer to Figure 5 The image shows a cross-section of the material applicator 10b of the second structure. Unless otherwise shown or described herein, the material applicator 10b is similar to material applicators 10 and 10a. Figures 1 to 4 ). Using something similar to Figures 1 to 4 The features indicated by the reference numerals shown and described herein are similar to those of applicators 10, 10a, and only the differences are described herein. The rear wall 131b of the material applicator 10b includes a plurality of acoustic focusing devices 124b, which are acoustic mirrors or reflectors. Each acoustic focusing device 124b is associated with a corresponding aperture in the aperture 112b and has a focal point proximate to that aperture 112b. Similar to applicators 10, 10a (… Figures 1 to 4 The oscillation of the micro-applier plate 114b generates a parallel initial wave Wb. This initial wave Wb is then reflected by the respective acoustic focusing devices 124b into secondary waves Wb' specifically directed at each individual aperture 112b. In an alternative configuration not specifically shown, multiple acoustic focusing devices 124b may be used, but each focusing device 124b focuses on more than one aperture 112b.

[0038] exist Figure 6In one particular configuration shown, the distance d1 between similar points on adjacent acoustic focusing devices can be equal to the distance d2 between similar points on adjacent apertures 112b, but other configurations can be used.

[0039] refer to Figure 7 The diagram shows a cross-section of the material applicator 10c of the third structure. Unless otherwise shown or described herein, the material applicator 10c is similar to material applicators 10, 10a, or 10b. Figures 1 to 6 ). Using something similar to Figures 1 to 6 The features indicated by the reference numerals shown and described herein are similar to those of applicators 10, 10a, and 10b, and only the differences are described herein. In the provided example, the microapplier plate 114c is not supported or oscillated by the actuator 120c. Alternatively, the acoustic focusing device 124c is an acoustic lens disposed between the microapplier plate 114c and the actuator 120c. In the provided example, the acoustic focusing device 124c defines a rear wall 131c and has a concave shape such that the rear wall 131c is concave in the direction facing the microapplier plate 114c. Activation of the actuator 120c forms an initial wave Wc propagating toward the acoustic focusing device 124c. The shape of the acoustic focusing device 124c focuses the sound wave such that secondary waves Wc' (i.e., those passing through the acoustic focusing device 124c) are focused toward the aperture 112c. In the provided example, the secondary waves Wc' are focused toward multiple apertures 112c. The space between the actuator 120c and the acoustic focusing device 124c can be any suitable gas, liquid or solid for propagating the initial wave Wc, or the actuator 120c can be in direct contact with the acoustic focusing device 124c.

[0040] refer to Figure 8 The diagram shows a cross-section of the material applicator 10d of the fourth structure. Unless otherwise shown or described herein, the material applicator 10d is similar to the material applicator 10c. Figure 7Features indicated by reference numerals similar to those shown and described in Figure 7 are similar to those of the applicator 10c, and only the differences are described herein. In the provided example, the acoustic focusing device 124d is an acoustic lens defining a rear wall 131d, but having a non-concave shape. Alternatively, the acoustic focusing device 124d is configured such that the sound velocity through the acoustic focusing device 124d varies across the acoustic focusing device 124d in a manner that causes the acoustic focusing device 124d to focus the secondary wave Wd' toward the aperture 112d. In a non-limiting example, the acoustic focusing device 124d may be configured to have different densities so that the sound velocity varies across the acoustic focusing device 124d, but other configurations may be used. In the provided example, the secondary wave Wd' is focused toward multiple apertures 112d. In alternative configurations, the sound velocity may vary across the acoustic focusing device 124d, and the acoustic focusing device 124d may have a concave shape.

[0041] refer to Figure 9 The diagram shows a cross-section of the material applicator 10e of the fifth structure. Unless otherwise shown or described herein, the material applicator 10e is similar to the material applicator 10c. Figure 7 Features indicated by reference numerals similar to those shown and described in Figure 7 are similar to those of the applicator 10c, and only the differences are described herein. In the provided example, the microapplier 110e includes a plurality of acoustic focusing devices 124e, which are acoustic lenses defining a concave portion of the rear wall 131e facing the aperture 112e. The shape of the acoustic focusing devices 124c focuses the sound waves such that the secondary waves We' are focused toward the respective apertures in the aperture 112e.

[0042] refer to Figure 10 The diagram shows a cross-section of the material applicator 10f of the sixth structure. Unless otherwise shown or described herein, the material applicator 10f is similar to the material applicator 10e. Figure 9Features indicated by reference numerals similar to those shown and described in Figure 9 are similar to those of the applicator 10e, and only the differences are described herein. In the provided example, the acoustic focusing device 124f is an acoustic lens defining a portion of the rear wall 131f, but the acoustic focusing device 124f has a non-concave shape. Alternatively, the acoustic focusing device 124f is configured such that the sound velocity through the acoustic focusing device 124f varies across the acoustic focusing device 124f in such a way that the acoustic focusing device 124f focuses the secondary wave Wf' toward the respective holes in the holes 112f. In a non-limiting example, the acoustic focusing device 124f may be configured to have different densities so that the sound velocity varies across the acoustic focusing device 124f, but other configurations may be used. In alternative structures, the sound velocity may vary across the acoustic focusing device 124f, and the acoustic focusing device 124f may have a concave shape.

[0043] refer to Figure 11 The diagram shows a cross-section of the material applicator 10g of the seventh structure. Unless otherwise shown or described herein, the material applicator 10g is similar to material applicators 10 and 10a. Figures 1 to 4 ). Using something similar to Figures 1 to 4 The features indicated by the reference numerals shown and described herein are similar to those of applicators 10, 10a, and only the differences are described herein. In the provided example, the microapplier plate 114g is not supported or oscillated by the actuator 120g. Instead, the actuator 120g defines at least a portion of the rear wall 131g and has a concave shape facing the microapplier plate 114g. The shape of the actuator 120g causes it to generate a wave Wg that has been focused toward the orifice 112g. Thus, the actuator 120g itself forms an acoustic focusing device 124g. In the provided example, the wave Wg is focused toward the plurality of orifices 112g.

[0044] refer to Figure 12 The image shows a cross-section of the material applicator 10h of the eighth structure. Unless otherwise shown or described herein, the material applicator 10h is similar to the material applicator 10g. Figure 11 ). Using something similar to Figure 11 The features indicated by the reference numerals shown and described herein are similar to those of the applicator 10g, and only the differences are described herein. In the provided example, the microapplier 110h includes a plurality of actuators 120h that define a concave portion of the rear wall 131h facing the orifice 112h. The shape of the actuators 120h forms an acoustic focusing device 124h, such that activating the actuators 120h propagates and focuses the acoustic wave Wh toward the respective orifice in the orifice 112h.

[0045] Therefore, the acoustic focusing device 124a-h focuses the sound waves toward the orifice 112a-h, which can result in higher power efficiency (e.g., lower power required) and higher droplet ejection speed, which can also reduce overspray and allow the use of fluids with higher viscosity.

[0046] As used herein, the phrases A, B, and C at least one should be interpreted as using non-exclusive logical OR to represent logic (A or B or C), and should not be interpreted as meaning "at least one of A, at least one of B, and at least one of C".

[0047] Unless otherwise expressly stated, all numerical values ​​indicating mechanical / thermal properties, percentage of composition, dimensions and / or tolerances or other characteristics should be understood to be modified by the words “about” or “approximately” when describing the scope of this disclosure. Such modifications are necessary for various reasons, including industrial practice, manufacturing techniques, and testing capabilities.

[0048] The terminology used herein is for the purpose of describing particular exemplary forms only and is not intended to be restrictive. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms. The terms “comprising” and “having” are inclusive and therefore specify the presence of the stated feature, integer, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein should not be construed as necessarily requiring performance in the specific order discussed or shown, unless specifically indicated by order. It should also be understood that additional or alternative steps may be employed.

[0049] The description in this disclosure is merely exemplary in nature, and therefore examples that do not depart from the spirit of this disclosure are intended to fall within its scope. Such examples should not be considered as departing from the spirit and scope of this disclosure. The broad teachings of this disclosure can be implemented in various forms. Therefore, while this disclosure includes specific examples, its true scope should not be limited thereto, as other modifications will become apparent upon examination of the drawings, description, and appended claims.

[0050] According to one embodiment of the invention, the acoustic focusing device is an acoustic lens configured such that the sound velocity passing through the acoustic lens varies along the acoustic lens, so as to focus the pressure wave toward the at least one aperture.

[0051] According to one embodiment of the invention, the density of the acoustic focusing device varies along the acoustic focusing device to focus the pressure wave toward the at least one aperture.

Claims

1. An atomizer for applying a coating, the atomizer comprising: A nozzle plate, the nozzle plate defining at least one orifice; An actuator configured to oscillate to generate a pressure wave within the fluid, thereby ejecting the fluid from the at least one orifice; and An acoustic focusing device configured to focus the pressure wave toward the at least one aperture; The acoustic focusing device is an acoustic lens having a concave side facing the at least one aperture, and the acoustic lens having a planar body arranged parallel to the nozzle plate, through which the sound velocity varies across the planar body to focus the pressure wave toward the at least one aperture.

2. The atomizer of claim 1, wherein the actuator is configured to oscillate the nozzle plate.

3. The atomizer of claim 2, wherein the actuator is integrally formed with the nozzle plate.

4. The atomizer of claim 1, wherein the acoustic focusing device is disposed between the actuator and the nozzle plate and is configured to focus the pressure wave toward the at least one orifice.

5. The atomizer of claim 1, wherein the actuator is spaced apart from the nozzle plate to define a reservoir between the nozzle plate and the actuator, wherein the actuator is shaped to focus the pressure wave such that the pressure wave becomes more focused as it gets closer to the nozzle plate.

6. The atomizer of claim 5, wherein the actuator has a curved shape having a focal point toward the nozzle plate.

7. The atomizer according to any one of claims 1-6, wherein the focal point of the acoustic focusing device is located at the at least one orifice.

8. The atomizer according to any one of claims 1-6, wherein the at least one hole is a plurality of holes.

9. The atomizer of claim 8, wherein the acoustic focusing device focuses the pressure wave toward the plurality of orifices.

10. The atomizer of claim 8, further comprising a plurality of the acoustic focusing devices, each acoustic focusing device focusing the pressure wave toward a corresponding aperture in the aperture.

11. The atomizer of claim 1, further comprising a plurality of the nozzle plates and a plurality of the actuators, each actuator configured to oscillate a corresponding nozzle plate among the nozzle plates, wherein the atomizer includes a plurality of acoustic focusing devices, each acoustic focusing device associated with a corresponding nozzle plate among the nozzle plates.

12. The atomizer according to any one of claims 1-6, wherein the actuator is formed of a piezoelectric material.

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