An aerosol generator including a plurality of atomizers

Abstract

The aerosol generator (200) for an aerosol generating device (300) includes the aerosol generator (200), the aerosol generator (200) including a plurality of surface acoustic wave atomizers (202, 203) and a supply element (205). Each surface acoustic wave atomizer (202, 203) includes a substrate (206, 211) including an active surface (208, 213) and at least one transducer (207, 212) positioned on the active surface (208, 213) of the substrate (206, 211) for generating surface acoustic waves on the active surface (208, 213) of the substrate (206, 211). An atomization region (204) is defined between the substrates (206, 211) of the plurality of surface acoustic wave atomizers (202, 203). The supply element (205) is positioned to supply a liquid aerosol-forming substrate to the atomization region (204).

Description

Technical Field

[0001] The present disclosure relates to an aerosol generator for an aerosol generating device, the aerosol generator including a plurality of surface acoustic wave atomizers and supply elements, respectively. The present disclosure also relates to an aerosol generating device including the aerosol generator.

Background Art

[0002] Aerosol generating systems in which an aerosol forming substrate is heated rather than burned are known in the art. Typically, in such aerosol generating systems, the aerosol is generated by the transfer of energy from the aerosol generator of the aerosol generating device to the aerosol forming substrate. For example, known aerosol generating devices include a heater arranged to heat and vaporize a liquid aerosol forming substrate.

[0003] It is desirable to provide an aerosol generator for an aerosol generating device that is compact and optimized for efficiency and flexibility.

Summary of the Invention

[0004] According to a first aspect of the present disclosure, there is provided an aerosol generator for an aerosol generating device, the aerosol generator including a plurality of surface acoustic wave atomizers and supply elements. Each surface acoustic wave atomizer includes a substrate including an active surface and at least one transducer located on the active surface of the substrate for generating a surface acoustic wave on the active surface of the substrate. A spray region is defined between the substrates of the plurality of surface acoustic wave atomizers. The supply element is arranged to supply a liquid aerosol forming substrate to the spray region.

[0005] The term "surface acoustic wave" is used herein to include Rayleigh waves, Lamb waves, and Love waves.

[0006] Advantageously, using a surface acoustic wave atomizer to spray a liquid aerosol-forming substrate provides improved control of the spraying process compared to other known aerosol generators such as electric heaters. In other words, the surface acoustic wave atomizer of the aerosol generator according to the present disclosure provides a reliable and constant amount of atomized liquid aerosol-forming substrate.

[0007] Advantageously, the power required by a surface acoustic wave atomizer to spray a liquid aerosol-forming substrate is less than the power required to spray the same amount of liquid aerosol-forming substrate using a known aerosol generator such as an electric heater.

[0008] Advantageously, by providing a plurality of surface acoustic wave atomizers, the control of the atomization of the liquid aerosol-forming substrate can be improved. Advantageously, providing a plurality of surface acoustic wave atomizers directed at a single spraying area can increase the area of the spraying area where the surface acoustic waves are delivered. In other words, by providing a plurality of surface acoustic wave atomizers directed at a single spraying area, the area within the spraying area where the liquid aerosol-forming substrate is sprayed can be increased.

[0009] The plurality of surface acoustic wave atomizers enables the surface acoustic waves to be directed at the spraying area from different directions. The plurality of surface acoustic wave atomizers may comprise a first surface acoustic wave atomizer configured to generate surface acoustic waves in a first direction and a second surface acoustic wave atomizer configured to generate surface acoustic waves in a second direction, the second direction being different from the first direction. In particular, by providing a plurality of surface acoustic wave atomizers configured to direct surface acoustic waves at a single spraying area from different directions, the area of the spraying area where the surface acoustic waves are delivered can be increased. Advantageously, providing a plurality of surface acoustic wave atomizers directed at a single spraying area from different directions may help prevent the liquid aerosol-forming substrate from being supplied to areas of the spraying area that do not receive the surface acoustic waves.

[0010] In some embodiments, a plurality of surface acoustic wave atomizers may be capable of directing surface acoustic waves having different characteristics toward a spray region. Thereby, a single aerosol generator having a single liquid supply may be optimized to generate aerosols from liquid aerosol-forming substrates having different characteristics.

[0011] The spray region is a common spray region for each of the plurality of surface acoustic wave atomizers and is defined between the substrates of the plurality of surface acoustic wave atomizers. Each of the plurality of surface acoustic wave atomizers is arranged such that the surface acoustic wave is directed toward the spray region.

[0012] Advantageously, providing a common spray region may reduce or minimize the size of each of the plurality of surface acoustic wave atomizers and the overall size of the aerosol generator. Advantageously, providing a common spray region may simplify the design and manufacture of an aerosol generating device including the aerosol generator. For example, providing a common spray region may facilitate a simple air flow path through the aerosol generating device.

[0013] The aerosol generator includes a plurality of surface acoustic wave atomizers. The aerosol generator may include any suitable number of surface acoustic wave atomizers. For example, the aerosol generator may include two, three, four, five, six, seven, eight, or nine surface acoustic wave atomizers. The plurality of surface acoustic wave atomizers may include at least two surface acoustic wave atomizers. The plurality of surface acoustic wave atomizers may include at least three surface acoustic wave atomizers. The plurality of surface acoustic wave atomizers may be composed of two surface acoustic wave atomizers. The plurality of surface acoustic wave atomizers may be composed of three surface acoustic wave atomizers.

[0014] In some preferred embodiments, the aerosol generator includes an even number of surface acoustic wave atomizers. When the aerosol generator includes an even number of surface acoustic wave atomizers, the surface acoustic wave atomizers may be provided in pairs of opposing surface acoustic wave atomizers. A pair of opposing surface acoustic wave atomizers may include a first surface acoustic wave atomizer arranged to direct surface acoustic waves in a first direction towards the spray region, and a second surface acoustic wave atomizer arranged to direct surface acoustic waves in a second direction towards the spray region, the second direction being parallel and opposite to the first direction.

[0015] The following preferred and optional features of the surface acoustic wave atomizer may be applied to the surface acoustic wave atomizers of the present disclosure.

[0016] Each of the plurality of surface acoustic wave atomizers includes a substrate including an active surface, and at least one transducer located on the active surface of the substrate for generating surface acoustic waves on the active surface of the substrate.

[0017] The substrate is formed from a substrate material. The substrate may be a piezoelectric material. The substrate may include a crystalline material. The substrate material may include a single crystal material. The substrate material may include a polycrystalline material. The substrate material may include at least one of quartz, ceramic, barium titanate (BaTiO3), and lithium niobate (LiNbO3). The ceramic may include lead zirconate titanate (PZT). The ceramic may include a doping material such as Ni, Bi, La, Nd, or Nb ions. The substrate material may be polarized. The substrate material may not be polarized. The substrate material may include both polarized and non-polarized materials.

[0018] In some embodiments, the substrate material may include an amorphous base material. The amorphous base material may include any material on which a piezoelectric material can be deposited. The amorphous base material may include a polymeric material. The amorphous base material may include a flexible or bendable material such as a flexible film. The flexible or bendable amorphous base material can be formed from any suitable material such as a plastic material. Nanocrystals or microcrystals of the piezoelectric material can be deposited on or otherwise fixed to the amorphous base material. The nanocrystals or microcrystals of the piezoelectric material may include any material that exhibits piezoelectric properties. For example, the piezoelectric material may include one or more of lead zirconate titanate (PZT), aluminum nitride (AlN), zinc oxide (ZnO), barium titanate (BaTiO3), and lithium niobate (LiNbO3). For example, the amorphous base material may include nanocrystals or microcrystals of zinc oxide (ZnO). In some embodiments, a flexible film of the piezoelectric material can be deposited on the amorphous base material. In some embodiments, a flexible film of a single-crystalline piezoelectric material can be deposited on the amorphous base material. For example, the piezoelectric material may include polyvinylidene fluoride (PVDF). The substrate material may include a flexible film of the amorphous base material and a flexible film of polyvinylidene fluoride (PVDF) deposited on the amorphous base material. The flexible film of polyvinylidene fluoride (PVDF) may be a single crystal.

[0019] Advantageously, by providing an amorphous base material, particularly a flexible or bendable amorphous base material, to the substrate material, the substrate can be formed in a curved or bent shape.

[0020] The substrate may include a surface treatment. The surface treatment may be applied to the active surface of the substrate. The surface treatment may include a coating. The coating may include a hydrophobic material. The coating may include a hydrophilic material. The coating may include a lipophobic material. The coating may include a lipophilic material.

[0021] In some preferred embodiments, each of the plurality of surface acoustic wave atomizers may include the same substrate material. In some embodiments, at least one of the plurality of surface acoustic wave atomizers includes a substrate material different from another one of the plurality of surface acoustic wave atomizers.

[0022] The substrate can have any suitable shape. In some embodiments, at least one of the plurality of surface acoustic wave atomizers includes a substrate having a shape different from another one of the plurality of acoustic wave atomizers. In some preferred embodiments, each of the substrates has the same shape.

[0023] The substrate may have a planar shape. In other words, the substrate may generally extend in one plane. In some embodiments, at least one of the plurality of surface acoustic wave atomizers includes a substrate having a planar shape. In some preferred embodiments, each of the substrates has a planar shape.

[0024] The substrate may have a non-planar shape. In other words, the substrate may have sections that extend in different planes. In some embodiments, the substrate may have a curved shape. In some embodiments, the substrate may have a first section extending in a first plane and a second section extending in a second plane, and the second plane is not parallel to the first plane.

[0025] In some embodiments, at least one of the surface acoustic wave atomizers includes a substrate having a planar shape, and at least one of the surface acoustic wave atomizers includes a substrate having a non-planar shape. In some embodiments, each of the surface acoustic wave atomizers includes a substrate having a planar shape. In some embodiments, each of the surface acoustic wave atomizers includes a substrate having a non-planar shape.

[0026] The substrate may have a cylindrical shape or a polyhedral shape. The substrate can have a cylindrical shape, an elliptical cylindrical shape, a cubic shape, a prismatic shape, a triangular prismatic shape, a trapezoidal prismatic shape, or an isosceles trapezoidal prismatic shape. In some preferred embodiments, each of the substrates has the shape of an isosceles trapezoidal prism.

[0027] The substrate includes an active surface on which surface acoustic waves are generated. The active surface may be planar. The active surface may be a non-planar surface. In some embodiments, all of the active surfaces of the substrates of the plurality of surface acoustic wave atomizers are planar active surfaces. In some embodiments, all of the active surfaces of the substrates of the plurality of surface acoustic wave atomizers are non-planar active surfaces. In some embodiments, some of the active surfaces of the substrates of the plurality of surface acoustic wave atomizers are planar active surfaces, and some of the active surfaces of the substrates of the plurality of surface acoustic wave atomizers are non-planar active surfaces.

[0028] The active surface may have any suitable shape. The active surface may have a circular shape, an elliptical shape, or the shape of any suitable polygon. The active surface may have a triangular, square, rectangular, pentagonal, hexagonal, or trapezoidal shape. In some preferred embodiments, the active surface has the shape of an isosceles trapezoid.

[0029] In some preferred embodiments, the active surface of each substrate of the plurality of surface acoustic wave atomizers has the same shape. In some embodiments, at least one of the surface acoustic wave atomizers includes a substrate having an active surface with a shape different from the shape of the active surface of at least one of the substrates of the other surface acoustic wave atomizers.

[0030] When the substrate includes a crystalline material, the active surface of the substrate may be defined by the lattice plane of the crystalline material.

[0031] The substrates of the plurality of surface acoustic wave atomizers may be arranged in any suitable arrangement.

[0032] In some embodiments, the substrates of the plurality of surface acoustic wave atomizers may be spaced apart. In other words, a gap or space may be provided between adjacent surface acoustic wave atomizers.

[0033] Preferably, the substrates of the plurality of surface acoustic wave atomizers are adjacent to each other. In other words, preferably, the substrates of the plurality of surface acoustic wave atomizers are in contact with each other. The plurality of surface acoustic wave atomizers may be in direct contact with each other. The plurality of surface acoustic wave atomizers may be in indirect contact with each other. When the substrates of the plurality of surface acoustic wave atomizers are adjacent to each other, the substrates may be connected to each other. For example, the substrates may be fixed together. The substrates may be fixed together by an adhesive. When adjacent substrates are fixed together by an adhesive, the adjacent substrates are in indirect contact with each other via a layer of adhesive between the substrates.

[0034] The substrates may be arranged to define an opening. Preferably, the substrates of the plurality of surface acoustic wave atomizers are adjacent to each other to define an opening surrounded by the substrates. The opening surrounded by the substrates is preferably in the spraying area. In some embodiments, the opening surrounded by the substrates may form a spraying area.

[0035] In some embodiments where each substrate has a planar active surface, the active surfaces of the substrates of the plurality of surface acoustic wave atomizers are positioned in a common plane. Advantageously, positioning the active surfaces of the substrates of the plurality of surface acoustic wave atomizers in a common plane can simplify the manufacture of the aerosol generator.

[0036] In some embodiments where each substrate has a planar active surface, the active surfaces of the substrates of the plurality of surface acoustic wave atomizers are positioned in a non-coplanar arrangement relative to each other. Advantageously, positioning the active surfaces of the substrates of the plurality of surface acoustic wave atomizers in a non-coplanar relationship with each other can make the aerosol generator more compact. Advantageously, positioning the active surfaces of the substrates of the plurality of surface acoustic wave atomizers in a non-coplanar relationship with each other can provide a space or volume between the substrates to accommodate a liquid supply or to provide an air flow path. Advantageously, positioning the active surfaces of the substrates of the plurality of surface acoustic wave atomizers in a non-coplanar relationship with each other can make it possible to control the air flow on the active surfaces.

[0037] In some preferred embodiments where each substrate has a planar active surface, the substrates of the plurality of surface acoustic wave atomizers are arranged to form a polyhedral shape. Advantageously, arranging the substrates of the plurality of surface acoustic wave atomizers in a polyhedral shape can make the aerosol generator compact.

[0038] In some preferred embodiments where the substrates of the plurality of surface acoustic wave atomizers are adjacent to each other and define an opening surrounded by the substrates, the opening is surrounded by the substrate forming the spray region, and the plurality of surface acoustic wave atomizers includes at least three surface acoustic wave atomizers. In some preferred embodiments where the plurality of surface acoustic wave atomizers includes at least three surface acoustic wave atomizers, each of the substrates may have an isosceles trapezoidal prism shape.

[0039] In some particularly preferred embodiments where the plurality of surface acoustic wave atomizers comprises at least three surface acoustic wave atomizers and each substrate has an isosceles trapezoidal prism shape, the active surface may have an isosceles trapezoidal shape, and the shortest ends of each planar isosceles trapezoidal shape may together define an opening. In these particularly preferred embodiments, the active surfaces of the substrates of the plurality of surface acoustic wave atomizers may be arranged in a non-coplanar arrangement such that the plurality of surface acoustic wave atomizers form a pyramid shape with the tips cut off. When the plurality of surface acoustic wave atomizers form a pyramid shape with the tips cut off, the spray region may be positioned at the narrow end of the pyramid with the tip cut off. When the plurality of surface acoustic wave atomizers form a pyramid shape with the tips cut off and the substrates are arranged to form an opening, the opening may be positioned at the narrow end of the pyramid with the tip cut off.

[0040] Advantageously, arranging the substrates of the plurality of surface acoustic wave atomizers in a substantially pyramid shape with the tips cut off can make it possible to make the aerosol generator compact.

[0041] In some embodiments, the substrate may comprise a flexible or bendable material. In these embodiments, the substrate may be formed in a bent or curved shape. When the substrate is formed in a bent or curved shape, the plurality of surface acoustic wave atomizers may be arranged in the form of a cylinder or a cone.

[0042] In embodiments where the substrates of the plurality of surface acoustic wave atomizers are adjacent to each other and define an opening surrounded by the substrates, the opening surrounded by the substrate forming the spray region may be such that the ends of each substrate may partially define the opening. Each end may have any suitable contour. For example, each end may have one of a square contour, a round contour, a triangular contour, or an inclined contour. Advantageously, providing a round, triangular, or inclined contour to each end may facilitate the delivery of the liquid aerosol forming substrate to the spray region.

[0043] Preferably, each of the at least one transducer is arranged to generate surface acoustic waves in a direction towards the spray region. When the substrate is arranged to define an opening, preferably, each of the at least one transducer is arranged to generate surface acoustic waves in a direction towards the opening.

[0044] The at least one transducer may comprise an interdigital transducer including a plurality of electrodes. The at least one transducer may comprise an interdigital transducer including an interleaved array of electrodes. Preferably, the plurality of electrodes are preferably substantially parallel to each other. Preferably, the interdigital transducer comprises a first electrode array and a second electrode array interleaved with the first electrode array. The first electrode array is preferably substantially parallel to the second electrode array.

[0045] The transducer may be configured to generate surface acoustic waves having a substantially linear wavefront. In embodiments where the transducer is an interdigital transducer including a plurality of electrodes, each electrode may be substantially linear.

[0046] The transducer can be configured to generate a surface acoustic wave having a curved wavefront. In an embodiment where the transducer is an interdigital transducer including a plurality of electrodes, each electrode may be curved. The transducer can be configured to generate a surface acoustic wave having a convex wavefront. Preferably, the transducer may be configured to generate a surface acoustic wave having a concave wavefront. Advantageously, the concave wavefront can provide a focusing effect. In other words, the concave wavefront can focus the generated surface acoustic wave towards a spray region smaller than the transducer. Advantageously, focusing the generated surface acoustic wave can increase the rate at which energy is delivered to the liquid aerosol forming substrate in the spray region.

[0047] The array of interleaved electrodes of the interdigital transducer may have a symmetric shape including a symmetry axis extending in one direction.

[0048] When the substrate comprises a crystalline material and the active surface of the substrate can be defined by the lattice planes of the crystalline material, the direction of the symmetry axis of the array of interleaved electrodes can be aligned with the lattice vectors of the lattice planes. Advantageously, aligning the direction of the symmetry axis of the array of interleaved electrodes with the lattice vectors of the lattice planes of the substrate can facilitate the generation of an acoustic wavefront having a desired shape. The desired shape may be a symmetric shape.

[0049] At least one transducer may be a unidirectional transducer or a bidirectional transducer. In some preferred embodiments, at least one transducer is a single-phase unidirectional transducer.

[0050] At least one transducer may be a single transducer. At least one transducer may be a plurality of transducers. In an embodiment where the surface acoustic wave atomizer comprises a plurality of transducers, preferably, each transducer is arranged on the active surface of the substrate such that the surface acoustic wave generated by the transducer moves towards the spray region.

[0051] Each surface acoustic wave atomizer may include any suitable number of transducers. For example, the surface acoustic wave atomizer may include one, two, three, or four transducers. Preferably, each surface acoustic wave atomizer includes the same number of transducers. The surface acoustic wave atomizer may include different numbers of transducers.

[0052] When a surface acoustic wave atomizer includes a plurality of transducers, preferably, each of the plurality of transducers is identical. However, in some embodiments, a surface acoustic wave atomizer including a plurality of transducers may include different transducers.

[0053] In embodiments where a surface acoustic wave atomizer includes a plurality of transducers, each transducer may include an impedance matching component. Providing an impedance matching component may be advantageous when the load impedances of the transducers are significantly different from each other. Providing an impedance matching component may be advantageous when the load impedance of the transducer is significantly different from the source impedance of the control device that generates the drive signal provided to the transducer.

[0054] In embodiments where a surface acoustic wave atomizer includes a plurality of transducers, the transducers may be connected in series. In embodiments where a surface acoustic wave atomizer includes a plurality of transducers, the transducers may be connected in parallel.

[0055] The spray region is defined between the substrates of the plurality of surface acoustic wave atomizers. Each of the plurality of surface acoustic wave atomizers is arranged such that the surface acoustic wave is directed toward the spray region. When the substrate is arranged to define an opening, the opening may be arranged within the spray region. In some embodiments, the opening may define the spray region. Preferably, each of at least one transducer is arranged to generate a surface acoustic wave in a direction toward the opening.

[0056] The aerosol generator may comprise a supply element. The supply element is arranged to supply a liquid aerosol-forming substrate to the spray region. If the substrate is arranged to define an opening, the supply element may be arranged in the opening.

[0057] The supply element may include any suitable type of supply element capable of supplying a liquid aerosol-forming substrate to the spray region.

[0058] The supply element may include at least one of an elongate channel or an elongate core. In some preferred embodiments, the supply element includes an elongate core extending into the spray region.

[0059] The supply element may include a channel extending at least partially through a substrate of at least one of a plurality of surface acoustic wave atomizers. The channel may extend between an inlet on an inert surface of a substrate of at least one of the plurality of surface acoustic wave atomizers and an outlet of the spray region. In these embodiments, the active surface of the substrate may be curved, inclined, or angled in the direction towards the inert surface in or around the spray region. Advantageously, curving or angling the active surface in or around the spray region towards the inert surface may facilitate delivery of the surface acoustic wave to the outlet.

[0060] In some preferred embodiments, each of the substrates includes an inert surface opposite the active surface. In these embodiments, the supply element may comprise a groove formed in the inert surface of at least one substrate, the groove having an end in fluid communication with the spray region.

[0061] In some particularly preferred embodiments, the plurality of surface acoustic wave atomizers includes a first surface acoustic wave atomizer including a first substrate and a second surface acoustic wave atomizer including a second substrate. In these preferred embodiments, the first substrate channel is in fluid communication with the spray region. In these particularly preferred embodiments, the first and second grooves may have complementary shapes.

[0062] The supply element may include a flow control element arranged to control the flow of the liquid aerosol-forming substrate into the spraying area. In embodiments where the supply element comprises a channel, preferably, the first flow control element is arranged to control the flow of the aerosol-forming substrate through the inlet of the channel.

[0063] The flow control element may include at least one inert element. The at least one inert element may include at least one of an elongate tube and an elongate core.

[0064] The flow control element may include at least one active element. The at least one active element may include at least one of a micropump, a syringe pump, a piston pump, and an electroosmotic pump.

[0065] Preferably, the control device is configured to provide a flow signal to the flow control element to enable the flow of the liquid aerosol-forming substrate into the common spraying area. The control device may be configured to provide a stop signal to the control element to disable the flow of the first liquid aerosol-forming substrate.

[0066] The aerosol generator may comprise a control device. Preferably, the control device is configured to provide a drive signal to at least one transducer of each of the plurality of surface acoustic wave atomizers to generate surface acoustic waves on the active surface of the substrate. In order to provide a drive signal to at least one transducer of each of the plurality of surface acoustic wave atomizers, the control device may comprise a signal generator configured to generate the drive signal and an amplifier configured to amplify the drive signal generated by the signal generator, such that the amplified drive signal can be supplied to at least one transducer.

[0067] In an embodiment where the surface acoustic wave atomizer comprises a plurality of transducers connected in series and the control device comprises an amplifier and a signal generator, the drive signal generated by the signal generator may be amplified by the amplifier and supplied to each of the plurality of transducers connected in series.

[0068] In an embodiment in which a surface acoustic wave atomizer includes a plurality of transducers connected in parallel and a control device includes an amplifier and a signal generator, a drive signal generated by the signal generator may be amplified by the amplifier and supplied to each of the plurality of transducers connected in parallel.

[0069] The control device may be configured to provide the same drive signal to at least one transducer of each of the plurality of surface acoustic wave atomizers. The control device may be configured to provide different drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers. Advantageously, by providing different drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers, the aerosol generator can change the characteristics of the aerosol generated by the generator, and the aerosol generator can be optimized to evaporate different liquid aerosol-forming substrates.

[0070] When the control device is configured to provide the same drive signal to at least one transducer of each of the plurality of surface acoustic wave atomizers, a splitter may be disposed between the control device and at least one transducer of each of the plurality of surface acoustic wave atomizers to split the drive signal into a plurality of channels, and each channel may be connected to only one of the at least one transducer. The use of a splitter can be beneficial in that the output of the splitter for each of the plurality of channels is independent of the load characteristics of each channel. This can be advantageous in that the provision of the drive signal to the remaining transducers can be maintained under the same conditions even if one of the at least one transducer is malfunctioning.

[0071] When the control device includes a signal generator and an amplifier, the splitter may be disposed between the amplifier and at least one transducer of each of the plurality of surface acoustic wave atomizers. This can enable the amplified signal to be provided to each of the at least one transducer even in an embodiment where the control device provides the same drive signal.

[0072] The control device can be configured to simultaneously provide drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers. Advantageously, by simultaneously providing drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers, an optimized spraying of the liquid aerosol forming substrate in the spraying area can be provided, which can enable easy programming of the control device.

[0073] The control device can be configured to continuously provide drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers. In other words, the control device can be configured to successively provide drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers. Advantageously, by continuously providing drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers, it can be possible to change the characteristics of the aerosol generated by the generating device over time.

[0074] When the control device is configured to continuously provide drive signals to at least one transducer of each of the plurality of surface acoustic wave atomizers, the control device may comprise a switch configured to select the transducer of at least one transducer to which the drive signal is provided. The control device may comprise a signal source. The signal source may be configured to determine the frequency of the drive signal. The signal source may determine the frequency of the drive signal according to the position of the switch. In other words, the frequency of the drive signal can be adapted to the characteristics of the transducer to which the drive signal is provided.

[0075] The switch can be configured to change its position in less than 1 millisecond. This enables continuous operation of at least one transducer even within a short time interval, and can enable the generation of aerosols with more specific properties over a given period.

[0076] The control device can be configured to provide drive signals to at least one transducer of each of a plurality of surface acoustic wave atomizers. In other words, the control device can be configured to selectively provide drive signals to at least one transducer of each of a plurality of surface acoustic wave atomizers. Advantageously, by providing drive signals to at least one transducer of each of a plurality of surface acoustic wave atomizers, it becomes possible to use the aerosol generator with different liquid aerosol forming substrates, and each surface acoustic wave atomizer is optimized to vaporize a different liquid aerosol forming substrate.

[0077] In some embodiments, the aerosol generator includes a plurality of control devices. In some embodiments, each surface acoustic wave atomizer includes a control device configured to provide a drive signal to at least one transducer.

[0078] In embodiments where the aerosol generator includes a plurality of control devices, each control device may be configured to provide a drive signal to only one of the at least one transducer. This configuration may be useful for each of the at least one transducer in different aerosol generators.

[0079] In embodiments where the surface acoustic wave atomizer includes a plurality of transducers, such as a plurality of transducers connected in series or parallel, the transducers may be arranged to define a resonance system having a characteristic frequency. The resonance system may be arranged to define a resonance frequency that is substantially equal to the resonance frequency of each of the at least one transducer. In the latter embodiment, the control device may be configured to provide a drive signal having a frequency that is substantially equal to the resonance frequency of one of the at least one transducer. When the drive signal has such a frequency, it has been found that the drive signal is mainly transmitted only to the transducer whose resonance frequency substantially matches the frequency of the drive signal. Such a configuration can enable continuous activation of at least one transducer without the need for dedicated components such as switches. In other words, one of the at least one transducers can be selectively activated by selecting an appropriate frequency for the drive signal.

[0080] In an embodiment where the aerosol generator comprises a flow control element and the aerosol generator comprises at least one control device, preferably, the control device is configured to provide a flow signal to the flow control element to enable flow to the spray region of the liquid aerosol forming substrate. Preferably, the control device is configured to provide a stop signal to the control element to disable the flow of the liquid aerosol forming substrate. Preferably, the control device is configured to provide a drive signal to at least one transducer of one or more surface acoustic wave atomizers only when the control device supplies a flow signal to the flow control element.

[0081] At least one of the plurality of surface acoustic wave atomizers may include at least one reflector. In some embodiments, each of the plurality of surface acoustic wave atomizers may include at least one reflector. Preferably, at least one reflector is located on the active surface of the substrate. Preferably, at least one reflector is arranged to reflect the surface acoustic wave generated by at least one transducer. Preferably, at least one reflector is arranged to reflect the surface acoustic wave generated by the transducer towards the spray region. Advantageously, a reflector arranged to reflect the surface acoustic wave towards the spray region can increase or maximize the efficiency of the surface acoustic wave atomizer.

[0082] At least one reflector may comprise one or more electrodes.

[0083] At least one reflector may include one or more portions of metal located on the active surface of the substrate. Each portion of the metal may have a linear shape. Each portion of the metal may have a curved shape. At least one reflector may include a plurality of metal portions. The plurality of metal portions may be arranged in a pattern on the active surface of the substrate. Each portion of the metal is preferably substantially parallel to an adjacent portion of the metal forming at least one reflector.

[0084] A portion of the substrate may form at least a part of at least one reflector. The substrate may define at least one protrusion, and at least one protrusion forms at least a part of at least one reflector. The substrate may define at least one recess, and at least one recess forms at least a part of at least one reflector.

[0085] The spraying region may be positioned between at least one transducer and at least one reflector.

[0086] The at least one reflector may be a single reflector. The at least one reflector may be a plurality of reflectors.

[0087] In an embodiment in which at least one of the plurality of surface acoustic wave atomizers includes a plurality of transducers, the at least one reflector may be a plurality of reflectors. Each transducer may be positioned on the opposite side of one reflector such that the spraying region is positioned between the transducer and the corresponding reflector.

[0088] At least one of the plurality of surface acoustic wave atomizers may include at least one absorber. The at least one absorber is preferably positioned on the active surface of the substrate of the surface acoustic wave atomizer. Preferably, the at least one absorber is arranged to absorb the surface acoustic waves generated by at least one transducer. A portion of the substrate may form at least a part of at least one absorber. The substrate may define at least one protrusion, and at least one protrusion forms at least a part of at least one absorber. The substrate may define at least one recess, and at least one recess forms at least a part of at least one absorber.

[0089] At least one absorber may include a material having a low density and one or more of a high viscosity such as polydimethylsiloxane (PDMS). Advantageously, providing the absorber with one or more materials having a low density and a high viscosity can supply the absorber with a relatively high sound absorption coefficient. Preferably, the absorber includes a material in which the speed of sound is relatively low. The absorber may include a porous material. In some preferred embodiments, the absorber includes polydimethylsiloxane (PDMS).

[0090] A portion of the substrate may form at least a part of at least one absorber. The substrate may define at least one protrusion, and at least one protrusion forms at least a part of at least one absorber. The substrate may define at least one recess, and at least one recess forms at least a part of at least one absorber.

[0091] According to the present disclosure, there is further provided an aerosol generating device including an aerosol generator according to the present disclosure. The aerosol generating device may include a control device for controlling at least one transducer of each surface acoustic wave atomizer. The aerosol generating device may include a power source. The aerosol generating device may include a liquid storage portion for receiving a liquid aerosol forming substrate. A supply element of the aerosol generator may be arranged to supply the liquid aerosol forming substrate from the liquid storage portion to the spraying region.

[0092] At least one liquid storage portion may be reusable. In other words, at least one liquid storage portion may be refillable by a user to refill the liquid aerosol forming substrate in the at least one liquid storage portion. The at least one liquid storage portion may comprise a filling port for inserting the liquid aerosol forming substrate into the liquid storage portion. The at least one liquid storage portion may comprise a filling valve between the filling port and the at least one liquid storage portion. Advantageously, the filling valve may enable the liquid aerosol forming substrate to flow into the at least one liquid storage portion through the filling port. Advantageously, the filling valve may prevent the liquid aerosol forming substrate from flowing out from the at least one liquid storage portion through the filling port.

[0093] At least one liquid storage portion may be replaceable. The at least one liquid storage portion may be removable from the aerosol generating device. The aerosol generating device may comprise a cartridge, the cartridge being removable from the aerosol generating device and the cartridge comprising at least one liquid storage portion.

[0094] The aerosol generating device may comprise a liquid aerosol forming substrate accommodated in the at least one liquid storage portion.

[0095] The liquid aerosol forming substrate may contain nicotine. The liquid aerosol forming substrate containing nicotine may be a nicotine salt matrix. The liquid aerosol forming substrate may contain plant-derived materials. The liquid aerosol forming substrate may contain tobacco. The liquid aerosol forming substrate may contain homogenized tobacco materials. The liquid aerosol forming substrate may contain non-tobacco-containing materials. The liquid aerosol forming substrate may contain homogenized plant-derived materials.

[0096] The liquid aerosol-forming substrate may comprise at least one aerosol former. The aerosol former is any suitable known compound or mixture of compounds that facilitates the formation of a high-density and stable aerosol during use. Suitable aerosol formers are well known in the art and include polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate, etc.), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.), but are not limited thereto. The aerosol former may be a polyhydric alcohol or a mixture thereof (such as triethylene glycol, 1,3-butanediol, and glycerin, etc.). The liquid aerosol-forming substrate may contain other additives and components (such as flavoring agents, etc.).

[0097] The liquid aerosol-forming substrate may contain water.

[0098] The liquid aerosol-forming substrate may contain nicotine and at least one aerosol former. The aerosol former may contain glycerin. The aerosol former may contain propylene glycol. The aerosol former may contain both glycerin and propylene glycol. The liquid aerosol-forming substrate may have a nicotine concentration of from about 0.1 percent to about 10 percent.

[0099] In embodiments where the inlet of the supply element comprises a plurality of inlets, at least one liquid storage portion may include a first liquid storage portion and a second liquid storage portion. The first liquid storage portion is for receiving a first liquid aerosol-forming substrate, and the first liquid storage portion is in fluid communication with a first inlet of the plurality of inlets. The second liquid storage portion is for receiving a second liquid aerosol-forming substrate, and the second liquid storage portion is in fluid communication with a second inlet of the plurality of inlets.

[0100] The aerosol generating device may comprise a flow control element arranged to control the flow rate of the liquid aerosol forming substrate from at least one liquid storage part to the channel of the supply element.

[0101] The flow control element may include at least one inert element. The at least one inert element may include at least one of an elongated tube and an elongated core. The at least one inert element may comprise an elongated tube. The at least one inert element may include an elongated core.

[0102] The flow control element may include at least one active element. The at least one active element may comprise a pump. The at least one active element may include at least one of a micropump, a syringe pump, a piston pump, and an electroosmotic pump. Preferably, the control device is arranged to provide a control signal to the at least one active element to control the flow rate of the liquid aerosol forming substrate from at least one liquid storage part to the channel of the supply element.

[0103] The control device may include an electrical circuit connected to a power source and an aerosol generator. The control device may comprise an electrical circuit connected to a power source and at least one transducer of each of a plurality of surface acoustic wave atomizers. When the aerosol generator comprises at least one control device, the control device of the aerosol generating device may be connected to at least one control device of the aerosol generator. The electrical circuit may comprise a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, or an application specific integrated circuit (ASIC) or other electronic circuit capable of providing control. The electrical circuit may comprise further electronic components. The electrical circuit may be configured to regulate the power supply from the power source to the aerosol generator. The electrical circuit may be configured to regulate the power supply from the power source to at least one transducer of each of the plurality of surface acoustic wave atomizers. The control device may be configured to continuously supply power to the aerosol generator after startup of the aerosol generating device. The control device may be configured to intermittently supply power to the aerosol generator. The control device may be configured to supply power to the aerosol generator for each puff.

[0104] Preferably, the control device and the power source are configured to provide an alternating voltage to the aerosol generator. Preferably, the control device and the power source are configured to provide an alternating voltage to at least one transducer of each of the plurality of surface acoustic wave atomizers. Preferably, the alternating voltage is a radio frequency alternating voltage. Preferably, the alternating voltage has a frequency of at least about 20 megahertz. Preferably, the alternating voltage has a frequency of from about 20 megahertz to about 100 megahertz, more preferably from about 20 megahertz to about 80 megahertz. Advantageously, an alternating voltage within these ranges may provide at least one of aerosol generation at a desired rate and a desired droplet size.

[0105] The power source may be any suitable type of power source. The power source may be a DC power source. In some preferred embodiments, the power source is a battery such as a rechargeable lithium-ion battery. The power source may be another form of charge storage device such as a capacitor. The power source may require recharging. The power source may have a capacity that allows for sufficient energy storage for one or more uses of the device. For example, the power source may have a capacity sufficient to allow for continuous generation of aerosol for about six minutes, or a multiple of six minutes, corresponding to the typical time taken to smoke one conventional cigarette. In another example, the power source may have a capacity sufficient to allow for a predetermined number of uses of the device, or for discontinuous activation. In one embodiment, the power source is a DC power source having a DC supply voltage in the range of about 2.5 volts to about 4.5 volts and a DC supply current in the range of about 1 ampere to about 10 amperes (corresponding to a DC power source in the range of about 2.5 watts to about 45 watts).

[0106] The aerosol generating device may advantageously comprise a DC / AC inverter, which may include a class C, class D or class E power amplifier. The DC / AC inverter may be arranged between the power source and the aerosol generator. The DC / AC inverter may be arranged between the power source and at least one transducer of each of a plurality of surface acoustic wave atomizers.

[0107] The aerosol generating device may further comprise a DC / DC converter between the power source and the DC / AC inverter.

[0108] The aerosol generating device may include a temperature sensor disposed in or around the spray region of the aerosol generator. The control device of the aerosol generating device may be configured to control the power supplied to the aerosol generator based on the temperature of the spray region sensed by the temperature sensor.

[0109] The aerosol generating device may include a liquid detection sensor in or around the spraying area of the aerosol generator. The control device of the aerosol generating device may be configured to supply power to the aerosol generator when liquid is detected in the spraying area by the liquid detection sensor.

[0110] For example, the aerosol generating device may include a smoking detector such as an airflow sensor or a pressure sensor. The smoking detector may be disposed within the airflow path of the aerosol generating device. The control device of the aerosol generating device may be configured to supply power to the aerosol generator when smoking on the device is detected by the smoking detector.

[0111] The aerosol generating device may include a device housing. The device housing may be elongated. The device housing may include any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composite materials containing one or more of these materials, or thermoplastic resins suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. The material is preferably light and not brittle.

[0112] The device housing may define an air inlet. The air inlet may be configured to allow ambient air to enter the device housing. The air inlet may be in fluid communication with the spraying area of the aerosol generator. The device may include any number of air inlets. The device may include a plurality of air inlets.

[0113] The device housing may include an air outlet. The air outlet may be configured to allow air to exit the device housing for delivery to the user. The air outlet may be in fluid communication with the spraying area of the aerosol generator. The aerosol generating device may include a mouthpiece. The mouthpiece may include the air outlet. The device may include any suitable number of air outlets. The device may include a plurality of air outlets.

[0114] In some preferred embodiments, the aerosol generator may comprise a device housing, and the aerosol generator is disposed within the device housing. In some of these preferred embodiments, the device housing defines at least one air inlet located upstream of the spraying area and at least one air outlet located downstream of the spraying area.

[0115] Advantageously, providing an air inlet located upstream of the spraying area and at least one air outlet located downstream of the spraying area may ensure that the air flow between the air inlet and the air outlet passes through the spraying area, which may result in vapor generated by the aerosol generator in the spraying area and confined by the air flow between the air inlet and the air outlet.

[0116] The aerosol generator may be disposed within the device housing so as to define an air flow path extending between at least one of a plurality of substrates and a portion of the device housing. The aerosol generator may be disposed within the device housing so as to define an air flow path extending between each of the plurality of substrates and a portion of the device housing.

[0117] Advantageously, defining an air flow path between the substrate and a portion of the device housing facilitates the control of the air flow through the air flow path and enables precise control of the dimensions of the air flow path.

[0118] The aerosol generator may be attached to a support by attachment means. The attachment means may include mechanical attachment. The mechanical attachment may include mechanical fasteners. The mechanical fasteners may comprise recesses in the support into which the aerosol generator can be snap-fitted. The mechanical attachment may include spring clamping. The spring clamping may include flat springs and may also include pogo pins. The attachment means may include an adhesive material such as adhesive tape or an adhesive.

[0119] The support may be provided with a power source. The support may include a control device. The support may include a splitter. The support may be a printed circuit board (PCB). The PCB may include a control device. The PCB may include a splitter.

[0120] When the control device includes an electrical circuit for connecting the power source and the aerosol generator, and the control device is included within the support, a wire bonding electrical connection may be provided between the electrical circuit of the support and the aerosol generator. In particular, when the support is a PCB, a wire bonding electrical connection may be provided between the control circuit of the PCB and the aerosol generator. Providing a wire bonding electrical connection may be advantageous in that the resulting electrical connection can be stable. The wire bonding electrical connection may be directly connected to the electrical circuit, for example, by soldering, screwing or clamping.

[0121] When the control device includes an electrical circuit for connecting the power source and the aerosol generator, the control device is included in the support, and the aerosol generator is attached to the support by spring clamping, and the spring clamping may be configured to provide an electrical connection between the electrical circuit of the support and the aerosol generator. Providing an electrical connection by spring clamping may be useful for the support and the aerosol generator to be easily separated from each other.

[0122] The support may be provided within the aerosol generator. In particular, the support may be provided within the device housing. The device housing may include a conductive piece configured to provide an electrical connection between the support and the aerosol generator. In particular, in embodiments where the support is a PCB, the PCB may include contact pins configured to be disposed in electrical contact with the conductive piece of the device housing. Similarly, the aerosol generator may include contact pins configured to be disposed in electrical contact with the conductive piece of the device housing. The PCB may include contact pins configured to be disposed in electrical contact with the contact pins of the aerosol generator. In embodiments where the PCB includes contact pins configured to be disposed in electrical contact with the contact pins of the aerosol generator, the electrical connection between the PCB and the aerosol generator may be established without the need for an intermediate conductive piece within the device housing. This may facilitate the assembly and replacement of the support and the aerosol generator.

[0123] When the control device is a PCB including an electrical circuit connecting the power supply and the aerosol generator, the contact pins of the PCB may be provided to the control circuit. The contact pins of the aerosol generator may be provided by at least one converter.

Brief Description of the Drawings

[0124] Although for illustrative purposes only, the present invention will be further described with reference to the following attached drawings.

[0125]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0126] FIGS. 1, 2, and 3 show an aerosol generator 100 according to a first embodiment of the present disclosure. The aerosol generator 100 includes a plurality of surface acoustic wave atomizers in the form of a first surface acoustic wave atomizer 102 and a second acoustic wave atomizer 103. The aerosol generator 100 further includes a spraying area 104 and a supply element 105 for supplying a liquid aerosol forming substrate to the spraying area 104.

[0127] The first surface acoustic wave atomizer 102 includes a substrate 106 including a sheet of piezoelectric material and a transducer 107 disposed on the active surface 108 of the substrate 106. The transducer 107 of the first surface acoustic wave atomizer 102 includes a first electrode array 109 and a second electrode array 110 interposed between the first electrode arrays 109. The first and second electrode arrays 109, 110 are linear and parallel to each other. In use, the transducer 107 of the first surface acoustic wave atomizer 102 generates a surface acoustic wave on the active surface 108 of the substrate 106. The linear shape of the first and second electrode arrays 109, 110 results in a surface acoustic wave having a linear wavefront directed towards the spray region 104.

[0128] The second surface acoustic wave atomizer 103 includes a substrate 111 including a sheet of piezoelectric material and a transducer 112 disposed on the active surface 113 of the substrate 111. The transducer 112 of the second surface acoustic wave atomizer 103 includes a first electrode array 114 and a second electrode array 115 interposed between the first electrode arrays 114. The first and second electrode arrays 114, 115 are linear and parallel to each other. In use, the transducer 112 of the second surface acoustic wave atomizer 103 generates a surface acoustic wave on the active surface 113 of the substrate 111. The linear shape of the first and second electrode arrays 114, 115 results in a surface acoustic wave having a linear wavefront directed towards the spray region 104.

[0129] The substrates 106, 111 of the first and second surface acoustic wave atomizers 102, 103 are arranged adjacent to each other at one end and fixed together with an adhesive (not shown). When the substrates 106, 111 are adjacent to each other, the substrates 106, 111 define an opening within the active surfaces 108, 113, which forms the spray region 104. In this embodiment, each substrate 106, 111 has a planar shape, and the substrates 106, 111 are arranged in a common plane as shown in FIG. 2. The first and second surface acoustic wave atomizers 102, 103 are substantially identical and are oriented in opposite directions. The first acoustic wave atomizer 102 generates surface acoustic waves on the active surface 108 in a first direction towards the spray region 104, and the second surface acoustic wave atomizer 103 generates surface acoustic waves on the active surface 113 in a second direction towards the spray region, and the second direction is parallel and opposite to the second direction.

[0130] The supply element 105 is disposed between the substrates 106, 111 located between the first and second surface acoustic wave atomizers 102, 103. The supply element 105 includes a channel 116 that extends through the substrates 106, 111. The inlet 117 of the channel 116 is formed between the inactive surface 118 of the substrate 106 of the first surface acoustic wave atomizer 102 and the inactive surface 119 of the substrate 111 of the second surface acoustic wave atomizer 103. The outlet 120 of the channel 116 is formed between the active surface 108 of the first surface acoustic wave atomizer 102 and the active surface 113 of the second surface acoustic wave atomizer 103. In this embodiment, the outlet 120 has a square shape with an axis parallel to the first and second directions. The channel 116 extends between the inlet 117 and the outlet 120. The outlet 120 is positioned within the spray region 104. During use, the liquid aerosol-forming substrate is supplied through the channel 116 to the spray region 104 and atomized by the surface acoustic waves generated by the first and second transducers 107, 112.

[0131] As shown in FIGS. 2 and 3, the channel 116 has a cross-sectional area that changes direction from the inlet 117 to the outlet 120. In particular, the channel 116 has a curved wedge shape such that the cross-sectional area of the channel 116 increases in the direction from the inlet 117 to the outlet 120. The smaller cross-sectional area of the channel 116 at the inlet 117 facilitates control of the flow rate of the liquid aerosol-forming substrate into the channel 116. The larger cross-sectional area of the channel 116 at the outlet 120 provides a larger surface area of the liquid aerosol-forming substrate in the spray region 104 and promotes atomization of the liquid aerosol-forming substrate. A curved transition is provided between the active surfaces 108, 113 and the channel 116 to facilitate the transfer of energy from the surface acoustic wave to the liquid aerosol-forming substrate within the spray region 104.

[0132] FIGS. 4 and 5 show an aerosol generator 200 according to a second embodiment of the present disclosure. The aerosol generator 200 comprises a plurality of surface acoustic wave atomizers in the form of a first surface acoustic wave atomizer 202 and a second acoustic wave atomizer 203. The aerosol generator 200 further includes a spray region 204 and a supply element 205 for supplying a liquid aerosol-forming substrate to the spray region 204.

[0133] The first surface acoustic wave atomizer 202 includes a substrate 206 including a sheet of piezoelectric material and a transducer 207 disposed on the active surface 208 of the substrate 206. The transducer 207 of the first surface acoustic wave atomizer 202 includes a first electrode array 209 and a second electrode array 210 interposed between the first electrode array 209. The first and second electrode arrays of the electrodes 209, 210 are curved and parallel to each other. In use, the transducer 207 generates a surface acoustic wave on the active surface 208 of the substrate 206. The curved shape of the first and second electrode arrays 209, 210 results in a surface acoustic wave having a concave wavefront that converges towards the spray region 204.

[0134] The second surface acoustic wave atomizer 203 includes a substrate 211 including a sheet of piezoelectric material and a transducer 212 disposed on an active surface 213 of the substrate 211. The transducer 212 of the second surface acoustic wave atomizer 203 includes a first electrode array 214 and a second electrode array 215 interposed between the first electrode arrays 214. The first and second electrode arrays 214, 215 are curved and parallel to each other. In use, the transducer 212 generates surface acoustic waves on the active surface 213 of the substrate 211. The curved shape of the first and second electrode arrays 214, 215 results in surface acoustic waves having a concave wavefront focused towards the spray region 204.

[0135] The substrates 206, 211 of the first and second surface acoustic wave atomizers 202, 203 are arranged to be adjacent to each other at one end and are fixed together with an adhesive (not shown). When the substrates 206, 211 are adjacent to each other, the substrates 206, 211 define an opening in the active surfaces 208, 213, which forms the spray region 204. In this embodiment, each of the substrates 206, 211 has a planar shape and the substrates 206, 211 are arranged in a common plane. The first and second surface acoustic wave atomizers 202, 203 are substantially identical and are oriented in opposite directions, the first acoustic wave atomizer 202 generates surface acoustic waves on the active surface 208 in a first direction towards the spray region 204, and the second surface acoustic wave atomizer 203 generates surface acoustic waves on the active surface 213 in a second direction towards the spray region, the second direction being opposite to the first direction.

[0136] The supply element 205 is disposed between the substrates 206, 211 of the first and second surface acoustic wave atomizers 202, 203, and the supply element 205 includes a channel 216 that extends through the substrates 206, 211. The inlet 217 of the channel 216 is formed between the inert surface 218 of the substrate 206 of the first surface acoustic wave atomizer 202 and the inert surface 219 of the substrate 211 of the second surface acoustic wave atomizer 203. The outlet 220 of the channel 216 is formed between the active surface 208 of the first surface acoustic wave atomizer 202 and the active surface 213 of the second surface acoustic wave atomizer 203. In this embodiment, the outlet 220 has a circular shape having a center that is the focus of the concave wavefront of the surface acoustic waves generated by the transducers 207, 212. The channel 216 extends between the inlet 217 and the outlet 220. The outlet 220 is positioned within the spray region 204. During use, a liquid aerosol-forming substrate is supplied through the channel 216 to the spray region 204 and is atomized by the surface acoustic waves generated by the first and second transducers 207, 212.

[0137] As shown in FIG. 5, the channel 216 has a cross-sectional area that varies in the direction from the inlet 217 to the outlet 220. In particular, the channel 216 has the shape of a curved funnel such that the cross-sectional area of the channel 216 increases in the direction from the inlet 217 to the outlet 220. A curved transition is also provided between the active surfaces 208, 213 and the channel 216.

[0138] FIG. 6 shows a cross-sectional view of an aerosol generating device 300 including an aerosol generator 200. The aerosol generating device 300 also includes a liquid storage portion 302 that includes a liquid aerosol-forming substrate 304 and a flow control element 306 that includes a micropump. The micropump is arranged to supply the liquid aerosol-forming substrate 304 from the liquid storage portion 302 to the inlet 217 of the aerosol generator 200.

[0139] The aerosol generating device 300 also comprises a power supply 308 with a rechargeable battery and a control device 310. The control device 310 is configured to provide a control signal to the flow control element 306 to control the flow rate of the liquid aerosol forming substrate 304 from the liquid storage portion 302 to the inlet 320 of the aerosol generator 200. The control device 310 is also configured to supply current from the power supply 308 to the aerosol generator 200 to drive the first and second transducers 207, 212.

[0140] The aerosol generating device 300 also comprises a housing 312 that includes the aerosol generator 200, the liquid storage portion 302, the flow control element 306, the power supply 308, and the control device 310. The housing 312 defines an air inlet 314, a mouthpiece 316, and an air outlet 318. In use, the user sucks on the mouthpiece 316 to draw air through the housing 312 from the air inlet 314 to the air outlet 318. The aerosol generated by the aerosol generator 200 is entrained in the airflow through the housing 312 for delivery to the user.

[0141] Figures 7 and 8 show an aerosol generator 400 according to a third embodiment of the present disclosure. The aerosol generator 400 comprises a plurality of surface acoustic wave atomizers in the form of a first surface acoustic wave atomizer 402 and a second acoustic wave atomizer 403. The aerosol generator 400 further includes a supply element 405 for supplying a liquid aerosol forming substrate to the spray region 404 and the spray region 404.

[0142] The first surface acoustic wave atomizer 402 includes a substrate 406 including a sheet of piezoelectric material and a transducer 407 disposed on an active surface 408 of the substrate 406. The second surface acoustic wave atomizer 403 includes a substrate 411 including a sheet of piezoelectric material and a transducer 412 disposed on an active surface 413 of the substrate 411. Each of the first and second transducers 407, 412 comprises first and second arrays of interdigitated electrodes as described with respect to the first and second transducers 107, 112 in FIGS. 1, 2 and 3. The first and second electrode arrays of each of the first and second transducers 407, 412 are linear and parallel to each other. In use, the transducer 407 of the first surface acoustic wave atomizer 402 generates a surface acoustic wave on the active surface 408 of the substrate 406. In use, the transducer 412 of the second surface acoustic wave atomizer 403 generates a surface acoustic wave on the active surface 413 of the substrate 411. The linear shape of the electrode arrays of the first and second transducers 407, 412 results in a surface acoustic wave having a linear wavefront directed towards the spray region 404.

[0143] The substrates 406, 411 of the first and second surface acoustic wave atomizers 402, 403 are arranged adjacent to each other at one end and are fixed together at their adjacent ends with an adhesive (not shown). When the substrates 406, 411 are adjacent to each other, the substrates 406, 411 define an opening 420 in the active surfaces 408, 413, which forms the spray region 404. In this embodiment, each of the substrates 406, 411 has a substantially cubic shape and the substrates 406, 411 are arranged in different non-parallel planes that intersect at the location where the substrates 406, 411 abut. Thus, the substrates 606, 411 are arranged in a generally triangular or V-shaped configuration.

[0144] In this embodiment, the supply element 405 is an elongate wick 416 disposed in the space between the substrates 406, 411 and extending from the opening 420 between the substrates 406, 411 at one end to the liquid reservoir 422 at the opposite end. The liquid reservoir 422 is also disposed in the space between the substrates 406, 411. The liquid reservoir 422 contains a liquid aerosol-forming substrate that is supplied to the spray region 404 by the elongate wick 416.

[0145] The aerosol generator 400 disposed in the aerosol generating device 500 is shown in FIG. 8. The aerosol generating device 500 includes a hollow substantially cylindrical housing 512 that defines an air inlet 514, and a mouthpiece 516 having an air outlet 518. The aerosol generator 400 is disposed within the housing 512 between the air inlet 514 and the mouthpiece 516, such that the air inlet 514 is located upstream of the spraying region 404 and the air outlet 518 is located downstream of the spraying region 404.

[0146] In use, the user sucks on the mouthpiece 516 and draws air through the housing 512 from the air inlet 514 to the air outlet 518. The aerosol generated by the aerosol generator 300 is entrained in the airflow through the housing 512 for delivery to the user.

[0147] The airflow between the air inlet 514 and the air outlet 518 is indicated by the dotted arrows in FIG. 8. The aerosol generator is positioned such that the airflow path is defined between the active surfaces 406, 411 of the first and second surface acoustic wave atomizers 402, 403, and the inner surface of the housing 512. The non-coplanar arrangement of the active surfaces 406, 411 allows the aerosol generator 400 and the housing 512 to have complementary shapes, which in turn allows for easy control of the size and shape of the airflow path between the aerosol generator 400 and the housing 512 during manufacture of the aerosol generating device 500. Control of the size and shape of the airflow path ensures that the draw resistance through the device is controlled during manufacture of the aerosol generating device 500.

[0148] FIGS. 9a, 9b, 9c show an aerosol generator 600 according to a fourth embodiment of the present disclosure. The aerosol generator 600 comprises a plurality of surface acoustic wave atomizers in the form of a first surface acoustic wave atomizer 602 and a second acoustic wave atomizer 603. The aerosol generator 600 further includes a spraying region 604 and a supply element 605 for supplying a liquid aerosol forming substrate to the spraying region 604.

[0149] The first surface acoustic wave atomizer 602 includes a substrate 606 including a sheet of piezoelectric material and a transducer 607 disposed on an active surface 608 of the substrate 606. The second surface acoustic wave atomizer 603 includes a substrate 611 including a sheet of piezoelectric material and a transducer 612 disposed on an active surface 613 of the substrate 611. Each of the first and second transducers 607, 612 comprises first and second arrays of interleaved electrodes as described with respect to the first and second transducers 107, 112 in FIGS. 1, 2 and 3. The first and second arrays of electrodes of each of the first and second transducers 607 and 612 are linear and parallel to each other. In use, the transducer 607 of the first surface acoustic wave atomizer 602 generates a surface acoustic wave on the active surface 608 of the substrate 606. In use, the transducer 612 of the second surface acoustic wave atomizer 603 generates a surface acoustic wave on the active surface 613 of the substrate 611. The linear shape of the electrode arrays of the first and second transducers 607, 612 results in a surface acoustic wave having a linear wavefront directed towards the spray region 604.

[0150] In this embodiment, each of the first and second surface acoustic wave atomizers 602, 603 includes substantially identical substrates 606, 611. Accordingly, only the substrate of the first surface acoustic wave atomizer 602 is described herein and shown in FIGS. 9b and 9c.

[0151] The substrate 606 of the first surface acoustic wave atomizer 602 has a generally rectangular profile with a generally planar active surface 608. The transducer 607 is disposed towards one end of the active surface 607 and the spray region 604 is disposed at the opposite end of the active surface 607.

[0152] The substrate 606 also comprises an inert surface 618 facing the active surface 606. The inert surface 618 comprises a groove 621 extending along the center of the length of the inert surface 618 from an opening 620 at an end having the spray region 604 to a cavity 622 formed at the end opposite to the inert surface 618. The groove 621 forms half of the supply element channel 616 of the aerosol generator, and the remaining half of the supply element channel 616 is formed by a corresponding groove in the inert surface of the substrate 613 of the second surface acoustic wave atomizer 603. The cavity 622 forms half of the liquid reservoir of the aerosol generator, and the remaining half of the liquid reservoir is formed by a corresponding cavity in the inert surface of the substrate 613 of the second surface acoustic wave atomizer 603.

[0153] The end of the active surface 608 of the substrate 606 of the first acoustic wave atomizer 602 has a tapered rounded profile towards the opening 620 in the spray region 604. The end of the active surface 608 is also curved or rounded towards the inert surface 618. This rounded profile of the substrate 606 towards the opening 620 and the inert surface 618 facilitates the delivery of the surface acoustic wave from the transducer 607 to the spray region 604.

[0154] When the first surface acoustic wave atomizer 602 and the second surface acoustic wave atomizer 603 are arranged for use, the substrate 606 of the first surface acoustic wave atomizer 602 covers the substrate 611 of the second surface acoustic wave atomizer 603 such that the inert surfaces of the substrates 606, 611 are in contact with each other. The groove 621 in the inert surface 618 of the substrate 606 of the first surface acoustic wave atomizer 602 covers the corresponding groove in the inert surface of the substrate 611 of the second surface acoustic wave atomizer 603, forming the channel 616. The cavity 622 in the inert surface 618 of the substrate 606 of the first surface acoustic wave atomizer 602 covers the corresponding cavity in the inert surface of the substrate 611 of the second surface acoustic wave atomizer 603, forming a liquid reservoir. The liquid reservoir is configured to hold a supply of a liquid aerosol-forming substrate. The channel 616 fluidly connects the liquid reservoir to the opening 620 in the spray region 604. Thus, the channel 616 forms a supply element. Advantageously, such an arrangement of surface acoustic wave atomizers provides a compact aerosol generator that is simple to manufacture.

[0155] Figures 10a and 10b show an aerosol generator 700 according to a fifth embodiment of the present disclosure. The aerosol generator 700 includes a plurality of surface acoustic wave atomizers in the form of six surface acoustic wave atomizers 702. The aerosol generator 700 further includes a spray region 704 and a supply element 705 for supplying a liquid aerosol-forming substrate to the spray region 704.

[0156] Each of the surface acoustic wave atomizers 702 is identical, and thus only one of the atomizers will be described.

[0157] The surface acoustic wave atomizer 702 includes a substrate including a sheet of piezoelectric material and a transducer 707 disposed on the active surface of the substrate. The transducer 707 comprises an array of first and second interleaved electrodes as described with respect to the first and second transducers 107, 112 in FIGS. 1, 2, and 3. The first and second electrode arrays of the transducer 707 are linear and parallel to each other. In use, the transducer 707 generates surface acoustic waves on the active surface of the substrate. The linear shape of the electrode array of the transducer 707 results in surface acoustic waves having a linear wavefront directed towards the spray region 704.

[0158] The substrate of each surface acoustic wave atomizer 702 generally has the shape of an isosceles trapezoidal prism, and the active surface has the shape of an isosceles trapezoid. The substrate is disposed within a generally truncated hexagonal pyramid where the long ends of the substrate are adjacent to each other. In this embodiment, the long ends of adjacent substrates are fixed together with an adhesive (not shown). The shortest ends of each substrate together define an opening 720. In this embodiment, the supply element 705 is in the form of an elongated core, and one end of the elongated core extends through the opening 720 to deliver a liquid aerosol-forming substrate to the opening 720 and the spray region 704. Advantageously, such a substrate configuration and arrangement provides a configuration of an aerosol generator that is relatively simple and compact to manufacture and arrange within an aerosol generating device.

[0159] It will be understood that the above-described embodiments are exemplary embodiments of the present disclosure, and other arrangements and configurations of the features according to the present disclosure are contemplated.

Claims

1. An aerosol generator for an aerosol generating device, wherein the aerosol generator comprises: a plurality of surface acoustic wave atomizers, each surface acoustic wave atomizer comprising: a substrate including an active surface, and at least one transducer located on the active surface of the substrate for generating a surface acoustic wave on the active surface of the substrate; a plurality of surface acoustic wave atomizers; a spray region defined between the substrates of the plurality of surface acoustic wave atomizers; and a supply element arranged to supply a liquid aerosol forming substrate to the spray region, the supply element including an elongated core extending into the spray region; an aerosol generator.

2. The aerosol generator according to claim 1, wherein the substrates of the plurality of surface acoustic wave atomizers abut against each other to define an opening surrounded by the substrates, and the opening forms the spray region.

3. The aerosol generator according to claim 2, wherein each of the at least one transducer is arranged to generate a surface acoustic wave in a direction towards the opening.

4. The aerosol generator according to claim 2 or 3, wherein each of the substrates has a planar shape.

5. The aerosol generator according to claim 4, wherein the substrates of the plurality of surface acoustic wave atomizers are arranged in a common plane.

6. The aerosol generator according to claim 4, wherein the substrates of the plurality of surface acoustic wave atomizers are positioned in non-identical planar arrangements relative to each other.

7. The aerosol generator according to claim 4, wherein the substrates of the plurality of surface acoustic wave atomizers are arranged to form a polyhedral shape.

8. The aerosol generator according to any one of claims 2 to 7, wherein the plurality of surface acoustic wave atomizers includes at least three surface acoustic wave atomizers.

9. The aerosol generator according to claim 8, wherein each of the substrates has a shape of an isosceles trapezoidal prism.

10. The aerosol generator according to claim 9, wherein each of the active surfaces of the substrates has a shape of an isosceles trapezoid, and the shortest ends of each of the isosceles trapezoid shapes together define the opening.

11. The aerosol generator according to any one of claims 2 to 10, wherein the ends of each of the substrates partially define the opening, and each end has a square profile, a round profile, a triangular profile, or an inclined profile.

12. An aerosol generating device, comprising: An aerosol generator according to any one of claims 1 to 11, a control device for controlling the at least one transducer of each surface acoustic wave atomizer, a power supply, and a liquid storage portion for receiving a liquid aerosol-forming substrate, the supply element being arranged to supply the liquid aerosol-forming substrate from the liquid storage portion to the spray region, the aerosol generating device comprising:

13. The aerosol generating device according to claim 12, further comprising a device housing, wherein the aerosol generator is positioned within the device housing, and the device housing defines at least one air inlet positioned upstream of the spray region and at least one air outlet positioned downstream of the spray region.

14. The aerosol generating device according to claim 13, when dependent on claim 6 or 7, wherein the aerosol generator is disposed within the device housing and defines an air flow path extending between at least one of the planar substrates and a part of the device housing.

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