Aerosol generator comprising a plurality of supply elements

Abstract

An aerosol generator (100) for an aerosol generating device (300) is provided. The aerosol generator comprises a surface acoustic wave nebulizer (102), a first supply element (104), a second supply element (105), and a controller (132). The surface acoustic wave nebulizer (102) comprises at least one substrate (106), the at least one substrate comprising an active surface (110) defining at least one atomization zone (116, 117). The surface acoustic wave nebulizer (102) further comprises a first transducer (108) positioned on the active surface (110) of the at least one substrate (106) and a second transducer (109) positioned on the active surface (110) of the at least one substrate (106). The first supply element (104) is arranged to supply a first liquid aerosol-forming substrate to the at least one atomization zone (116, 117). The second supply element (105) is arranged to supply a second liquid aerosol-forming substrate to the at least one atomization zone (116, 117). The controller (132) is configured to provide a first drive signal to the first transducer (108) for generating surface acoustic waves on the active surface (110) of at least one substrate (106). The controller (132) is configured to provide a second drive signal to the second transducer (109) for generating surface acoustic waves on the active surface (110) of at least one substrate (106). The controller (132) is configured to provide the first drive signal to the first transducer (108) only when the first liquid aerosol-forming substrate is supplied to at least one atomization region (116, 117) by the first supply element (104). The controller (132) is configured to provide the second drive signal to the second transducer (109) only when the second liquid aerosol-forming substrate is supplied to at least one atomization region (116, 117) by the second supply element (105).

Description

Technical Field

[0001] The present disclosure relates to an aerosol generator for an aerosol generating device, the aerosol generator comprising a surface acoustic wave nebulizer and a first supply element and a second supply element. The present disclosure also relates to an aerosol generating device comprising the aerosol generator.

[0002] Aerosol generating systems in which an aerosol-forming substrate is heated without combustion are known in the art. Typically, in such aerosol generating systems, an aerosol is generated by energy transfer from an aerosol generator of an aerosol generating device to the aerosol-forming substrate. For example, a known aerosol generating device comprises a heater arranged to heat and evaporate a liquid aerosol-forming substrate. Background Art

[0003] Typically, an aerosol generating device is designed and optimized for vaporizing or atomizing a specific liquid aerosol-forming substrate. For example, an aerosol generating device may be designed and optimized for vaporizing a liquid having a specific volatility, viscosity, etc.

[0004] It is desirable to provide an aerosol generator for an aerosol-generating device that facilitates the aerosolization of a variety of liquid aerosol-forming substrates. Summary of the invention

[0005] According to a first aspect of the present disclosure, an aerosol generator for an aerosol generating device is provided. The aerosol generator comprises a surface acoustic wave nebulizer, a first supply element, a second supply element and a controller. The surface acoustic wave nebulizer comprises at least one substrate, the substrate comprising an active surface defining at least one atomization zone. The surface acoustic wave nebulizer also comprises a first transducer positioned on the active surface of at least one substrate and a second transducer positioned on the active surface of at least one substrate. The first supply element is arranged to supply a first liquid aerosol-forming substrate to at least one atomization zone.

[0006] The second supply element is arranged to supply the second liquid aerosol-forming substrate to at least one atomization zone. The controller is configured to provide a first drive signal to the first transducer for generating surface acoustic waves on the active surface of at least one substrate. The controller is configured to provide a second drive signal to the second transducer for generating surface acoustic waves on the active surface of at least one substrate. The controller is configured to provide the first drive signal to the first transducer only when the first liquid aerosol-forming substrate is supplied to at least one atomization zone by the first supply element. The controller is configured to provide the second drive signal to the second transducer only when the second liquid aerosol-forming substrate is supplied to at least one atomization zone by the second supply element.

[0007] The term "surface acoustic wave" is used herein to include Rayleigh waves, Lamb waves, and Love waves.

[0008] Advantageously, using a surface acoustic wave nebulizer to atomize the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate provides improved control over the atomization process when compared to other known aerosol generators such as electric heaters. In other words, the surface acoustic wave nebulizer of the aerosol generator according to the present disclosure provides a reliable and consistent amount of atomized liquid aerosol-forming substrate.

[0009] Advantageously, the power required by a surface acoustic wave nebuliser for aerosolising a liquid aerosol-forming substrate is less than the power required to aerosolise the same amount of liquid aerosol-forming substrate using known aerosol generators such as electric heaters.

[0010] Advantageously, the use of a single surface acoustic wave nebuliser for aerosolising the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate simplifies the design and manufacture of the aerosol generator.

[0011] Advantageously, the use of a surface acoustic wave nebuliser comprising a first transducer and a second transducer facilitates each transducer being optimised for nebulising the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate respectively.

[0012] Preferably, the at least one substrate comprises a common substrate on which the first transducer and the second transducer are positioned. Advantageously, the common substrate simplifies the design and manufacture of the surface acoustic wave atomizer.

[0013] At least one atomization region may be a common atomization region. In embodiments where the at least one substrate comprises a common substrate, the common atomization region is defined by the common substrate.

[0014] Advantageously, providing a common substrate defining a common atomization region can reduce or minimize the size of the surface acoustic wave nebulizer. Advantageously, providing a common atomization region can simplify the design and manufacture of an aerosol generating device including an aerosol generator. For example, providing a common atomization region can facilitate a simple airflow path through the aerosol generating device.

[0015] In the embodiment where the aerosol generator includes a common atomization zone, the aerosol generator may include a common supply element that provides a fluid communication between the common atomization zone and each of the first supply element and the second supply element. The common supply element may include a common channel extending at least partially through the substrate. The common supply element may include a common outlet on the active surface of the substrate and positioned in the common atomization zone. Preferably, the common channel is in fluid communication with the common outlet.

[0016] The first supply element may include a first channel extending at least partially through the substrate. The first channel may extend between a first inlet on the passive surface of the substrate and a common channel. The first channel may be a capillary. The second supply element may include a second channel extending at least partially through the substrate. The second channel may be a capillary. The second channel may extend between a second inlet on the passive surface of the substrate and the common channel.

[0017] The first supply element may include a first transducer. During use, the surface acoustic waves generated by the first transducer can draw the first liquid aerosol-forming substrate into at least one atomization zone. In other words, the first liquid aerosol-forming substrate is drawn into at least one atomization zone only when the controller provides the first drive signal to the first transducer. In embodiments where the first supply element includes a first channel, the surface acoustic waves generated by the first transducer can draw the first liquid aerosol-forming substrate through the first channel.

[0018] The second supply element may include a second transducer. During use, the surface acoustic waves generated by the second transducer can draw the second liquid aerosol-forming substrate into at least one atomization zone. In other words, the second liquid aerosol-forming substrate is drawn into at least one atomization zone only when the controller provides the second drive signal to the second transducer. In an embodiment in which the second supply element includes a second channel, the surface acoustic waves generated by the second transducer can draw the second liquid aerosol-forming substrate through the second channel.

[0019] The first supply element may comprise a first flow control element arranged to control the flow of the first liquid aerosol-forming substrate to the common atomisation region. In embodiments where the first supply element comprises a first channel, preferably the first flow control element is arranged to control the flow of the first aerosol-forming substrate through the first inlet and into the first channel.

[0020] The second supply element may comprise a second flow control element arranged to control the flow of the second liquid aerosol-forming substrate to the common atomisation region. In embodiments where the second supply element comprises a second channel, preferably the second flow control element is arranged to control the flow of the second aerosol-forming substrate through the second inlet and into the second channel.

[0021] Each of the first flow control element and the second flow control element may include at least one passive element. The at least one passive element may include at least one of a capillary tube and a capillary wick.

[0022] Each of the first flow control element and the second flow control element may include at least one active element. The at least one active element may include at least one of a micro pump, a syringe pump, a piston pump, and an electroosmotic pump.

[0023] Preferably, the controller is configured to provide a first flow signal to the first flow control element so that the first liquid aerosol-forming substrate can flow to the common atomization area. Preferably, the controller is configured to provide a second flow signal to the second flow control element so that the second liquid aerosol-forming substrate can flow to the common atomization area. Preferably, the controller is configured to provide a first stop signal to the first control element to deactivate the flow of the first liquid aerosol-forming substrate when the controller provides the second flow signal to the second control element. Preferably, the controller is configured to provide a second stop signal to the second control element to deactivate the flow of the second liquid aerosol-forming substrate when the controller provides the first flow signal to the first control element.

[0024] Advantageously, a controller configured to provide a flow signal and a stop signal to the first flow control element and the second flow control element can prevent the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate from being simultaneously supplied to the common atomization region. Advantageously, supplying only one of the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate to the common atomization region at a time facilitates the controller to drive only the first transducer or the second transducer. In other words, the need to drive the first transducer and the second transducer simultaneously can be reduced or eliminated. Advantageously, reducing or eliminating the need to drive the first transducer and the second transducer simultaneously can reduce the power requirements of the aerosol generating device including the aerosol generator.

[0025] The controller may be configured to alternate between providing the first flow signal and providing the second flow signal.In other words, the controller may be configured to switch back and forth between supplying the first liquid aerosol-forming substrate to the common aerosolization region and supplying the second liquid aerosol-forming substrate to the common aerosolization region.

[0026] Advantageously, alternating between atomizing the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate provides for alternating delivery of the first aerosol and the second aerosol to the user. The controller may be configured to receive a user input indicating a user selection between delivering the first aerosol or the second aerosol. The controller may be configured to provide the first flow signal or the second flow signal depending on the user input.

[0027] The controller may be configured to rapidly alternate between providing the first flow signal and the second flow signal. The controller may be configured to alternate between providing the first flow signal and the second flow signal at least once every 1 second, preferably at least once every 0.1 second. Advantageously, the rapid alternating delivery of the first aerosol and the second aerosol may be perceived by the user as simultaneous delivery of the first aerosol and the second aerosol.

[0028] At least one atomization zone may include a first atomization zone positioned on the active surface of the substrate to receive surface acoustic waves generated by the first transducer, and a second atomization zone positioned on the active surface of the substrate to receive surface acoustic waves generated by the second transducer. Preferably, the first supply element is arranged to supply the first liquid aerosol-forming substrate to the first atomization zone, and the second supply element is arranged to supply the second liquid aerosol-forming substrate to the second atomization zone.

[0029] Advantageously, the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate are supplied to the first atomization zone and the second atomization zone to facilitate the simultaneous but separate atomization of the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate. Advantageously, the simultaneous atomization of the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate facilitates the mixing of aerosols generated by the first aerosol-forming substrate and the second aerosol-forming substrate. Advantageously, the separate atomization of the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate facilitates the customization of atomization parameters for each of the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate. For example, each of the first transducer and the second transducer can be specifically configured to be used to atomize the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate, respectively. Specifically, the configuration of each of the first transducer and the second transducer can depend on one or more fluid properties of the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate, such as volatility or viscosity.

[0030] The first supply element may include a first channel extending through the substrate. The first channel may be a capillary tube. The first channel may extend between a first inlet on the passive surface of the substrate and a first outlet on the active surface of the substrate, wherein the first outlet is positioned within the first atomization zone.

[0031] The second supply element may include a second channel extending through the substrate. The second channel may be a capillary tube. The second channel may extend between a second inlet on the passive surface of the substrate and a second outlet on the active surface of the substrate, wherein the second outlet is positioned in the second atomization zone.

[0032] The first supply element may include a first transducer. During use, the surface acoustic waves generated by the first transducer can draw the first liquid aerosol-forming substrate into at least one atomization zone. In other words, the first liquid aerosol-forming substrate is drawn into at least one atomization zone only when the controller provides the first drive signal to the first transducer. In embodiments where the first supply element includes a first channel, the surface acoustic waves generated by the first transducer can draw the first liquid aerosol-forming substrate through the first channel.

[0033] The second supply element may include a second transducer. During use, the surface acoustic waves generated by the second transducer can draw the second liquid aerosol-forming substrate into at least one atomization zone. In other words, the second liquid aerosol-forming substrate is drawn into at least one atomization zone only when the controller provides the second drive signal to the second transducer. In an embodiment in which the second supply element includes a second channel, the surface acoustic waves generated by the second transducer can draw the second liquid aerosol-forming substrate through the second channel.

[0034] The first supply element may comprise a first flow control element arranged to control the flow of the first liquid aerosol-forming substrate to the first atomisation region. In embodiments wherein the first supply element comprises a first channel, preferably the first flow control element is arranged to control the flow of the first aerosol-forming substrate through the first inlet and into the first channel.

[0035] The second supply element may comprise a second flow control element arranged to control the flow of the second liquid aerosol-forming substrate to the second atomisation region. In embodiments where the second supply element comprises a second channel, preferably the second flow control element is arranged to control the flow of the second aerosol-forming substrate through the second inlet and into the second channel.

[0036] Each of the first flow control element and the second flow control element may include at least one passive element. The at least one passive element may include at least one of a capillary tube and a capillary wick.

[0037] Each of the first flow control element and the second flow control element may include at least one active element. The at least one active element may include at least one of a micro pump, a syringe pump, a piston pump, and an electroosmotic pump.

[0038] Preferably, the controller is configured to provide a first flow signal to the first flow control element to enable the first liquid aerosol-forming substrate to flow to the first atomization zone. Preferably, the controller is configured to provide a second flow signal to the second flow control element to enable the second liquid aerosol-forming substrate to flow to the second atomization zone. Preferably, the controller is configured to provide a first stop signal to the first control element to deactivate the flow of the first liquid aerosol-forming substrate. Preferably, the controller is configured to provide a second stop signal to the second control element to deactivate the flow of the second liquid aerosol-forming substrate.

[0039] Preferably, the controller is configured to provide a first drive signal to the first transducer only when the first liquid aerosol-forming substrate is supplied to the first atomization zone by the first supply element.Preferably, the controller is configured to provide a second drive signal to the second transducer only when the second liquid aerosol-forming substrate is supplied to the second atomization zone by the second supply element.

[0040] The surface acoustic wave atomizer may include at least one reflector. Preferably, the at least one reflector is positioned on the active surface of at least one substrate. Preferably, the at least one reflector is arranged to reflect the surface acoustic waves generated by at least one of the first transducer and the second transducer. Preferably, the at least one reflector is arranged to reflect the surface acoustic waves generated by at least one of the first transducer and the second transducer toward at least one atomization area. Advantageously, a reflector arranged to reflect the surface acoustic waves toward at least one atomization area can increase or maximize the efficiency of the surface acoustic wave atomizer. At least one reflector may be arranged to reflect the surface acoustic waves generated by each of the first transducer and the second transducer toward at least one atomization area.

[0041] In an embodiment wherein at least one atomization zone comprises a first atomization zone and a second atomization zone, at least one reflector may comprise a common reflector, wherein the first atomization zone is positioned between the common reflector and the first transducer, and wherein the second atomization zone is positioned between the common reflector and the second transducer.

[0042] Advantageously, providing a common reflector may simplify the design and construction of the surface acoustic wave nebulizer.

[0043] Advantageously, the common reflector may prevent the surface acoustic waves generated by the first transducer from being transmitted to the second atomization zone.

[0044] Advantageously, the common reflector may prevent surface acoustic waves generated by the second transducer from being transmitted to the first atomization zone.

[0045] At least one reflector may include one or more electrodes.

[0046] At least one reflector may include one or more portions of metal positioned on the active surface of at least one substrate. Each portion of metal may have a linear shape. Each portion of metal may have a curved shape. At least one reflector may include multiple portions of metal. Multiple portions of metal may be arranged in a certain pattern on the active surface of at least one substrate. Preferably, each portion of metal is substantially parallel to an adjacent portion of metal forming at least one reflector.

[0047] A portion of at least one substrate may form at least a portion of at least one reflector. At least one substrate may define at least one protrusion, wherein at least one protrusion forms at least a portion of the at least one reflector. At least one substrate may define at least one recess, wherein at least one recess forms at least a portion of at least one reflector.

[0048] The surface acoustic wave atomizer may comprise at least one absorber. Preferably, the at least one absorber is positioned on an active surface of the at least one substrate. Preferably, the at least one absorber is arranged to absorb surface acoustic waves generated by at least one of the first transducer and the second transducer.

[0049] In embodiments where at least one atomizing region comprises a first atomizing region and a second atomizing region, at least one absorber may comprise a common absorber, wherein the first atomizing region is positioned between the common absorber and the first transducer, and wherein the second atomizing region is positioned between the common absorber and the second transducer.

[0050] Advantageously, providing a common absorber may simplify the design and construction of the surface acoustic wave nebulizer.

[0051] Advantageously, the common absorber may prevent the surface acoustic waves generated by the first transducer from being transmitted to the second atomization zone.

[0052] Advantageously, the common absorber may prevent surface acoustic waves generated by the second transducer from being transmitted to the first atomization zone.

[0053] At least one absorber may include a material having at least one of low density, low acoustic velocity, and high viscosity. At least one absorber may include polydimethylsiloxane.

[0054] A portion of at least one substrate may form at least a portion of at least one absorber. At least one substrate may define at least one protrusion, wherein at least one protrusion forms at least a portion of the at least one absorber. At least one substrate may define at least one recess, wherein at least one recess forms at least a portion of at least one absorber.

[0055] The aerosol generator may include a third transducer positioned on the active surface of at least one substrate and a third supply element arranged to supply a third liquid aerosol-forming substrate to at least one atomization zone. Preferably, the controller is configured to provide a third drive signal to the third transducer for generating surface acoustic waves on the active surface of at least one substrate, wherein the controller is configured to provide the third drive signal to the third transducer only when the third liquid aerosol-forming substrate is supplied to the at least one atomization zone by the third supply element.

[0056] In embodiments wherein at least one substrate comprises a common substrate, preferably the third transducer is located on the common substrate.

[0057] In embodiments where the aerosol generator comprises a common supply element, the third supply element may comprise a third channel extending at least partially through the substrate. The third channel may be a capillary tube. The third channel may extend between a third inlet on the passive surface of the substrate and the common channel.

[0058] The third supply element may include a third transducer. During use, the surface acoustic waves generated by the third transducer can draw the third liquid aerosol-forming substrate into at least one atomization zone. In other words, only when the controller provides the third drive signal to the third transducer, the third liquid aerosol-forming substrate is drawn into at least one atomization zone. In an embodiment in which the third supply element includes a third channel, the surface acoustic waves generated by the third transducer can draw the third liquid aerosol-forming substrate through the third channel.

[0059] The third supply element may comprise a third flow control element arranged to control the flow of the third liquid aerosol-forming substrate to the common atomisation region. In embodiments where the third supply element comprises a third channel, preferably the third flow control element is arranged to control the flow of the third aerosol-forming substrate through the third inlet and into the third channel.

[0060] The third flow control element may include at least one passive element. The at least one passive element may include at least one of a capillary tube and a capillary wick.

[0061] The third flow control element may include at least one active element. The at least one active element may include at least one of a micro pump, a syringe pump, a piston pump, and an electroosmotic pump.

[0062] Preferably, the controller is configured to provide a third flow signal to the third flow control element to enable the third liquid aerosol-forming substrate to flow to the common atomization area. Preferably, the controller is configured to provide a third stop signal to the third control element to deactivate the flow of the third liquid aerosol-forming substrate when the controller provides the first flow signal to the first control element or provides the second flow signal to the second control element.

[0063] In an embodiment in which at least one atomization zone includes a first atomization zone and a second atomization zone, at least one atomization zone may further include a third atomization zone positioned on the active surface to receive surface acoustic waves generated by a third transducer, wherein a third supply element is arranged to supply a third liquid aerosol-forming substrate to the third atomization zone.

[0064] The third supply element may include a third channel extending through the substrate. The third channel may be a capillary. The third channel may extend between a third inlet on the passive surface of the substrate and a third outlet on the active surface of the substrate, wherein the third outlet is positioned in the third atomization zone.

[0065] The third supply element may include a third transducer. During use, the surface acoustic waves generated by the third transducer can draw the third liquid aerosol-forming substrate into at least one atomization zone. In other words, only when the controller provides the third drive signal to the third transducer, the third liquid aerosol-forming substrate is drawn into at least one atomization zone. In an embodiment in which the third supply element includes a third channel, the surface acoustic waves generated by the third transducer can draw the third liquid aerosol-forming substrate through the third channel.

[0066] The third supply element may comprise a third flow control element arranged to control the flow of the third liquid aerosol-forming substrate to the third atomisation zone. In embodiments where the third supply element comprises a third channel, preferably the third flow control element is arranged to control the flow of the third aerosol-forming substrate through the third inlet and into the third channel.

[0067] The third flow control element may include at least one passive element. The at least one passive element may include at least one of a capillary tube and a capillary wick.

[0068] The third flow control element may include at least one active element. The at least one active element may include at least one of a micro pump, a syringe pump, a piston pump, and an electroosmotic pump.

[0069] Preferably, the controller is configured to provide a third flow signal to the third flow control element to enable the third liquid aerosol-forming substrate to flow to the third aerosolization zone.Preferably, the controller is configured to provide a third stop signal to the third control element to deactivate the flow of the third liquid aerosol-forming substrate.

[0070] Preferably, the controller is configured to provide the third drive signal to the third transducer only when the third liquid aerosol-forming substrate is supplied to the third aerosolisation region by the third supply element.

[0071] In embodiments where the surface acoustic wave nebulizer comprises at least one reflector, the at least one reflector may be arranged to reflect the surface acoustic waves generated by the third transducer.The at least one reflector may be arranged to reflect the surface acoustic waves generated by the third transducer towards the at least one nebulization region.

[0072] In an embodiment wherein at least one atomization zone comprises a first atomization zone, a second atomization zone, and a third atomization zone, at least one reflector may comprise a common reflector, wherein the first atomization zone is positioned between the common reflector and the first transducer, wherein the second atomization zone is positioned between the common reflector and the second transducer, and wherein the third atomization zone is positioned between the common reflector and the third transducer.

[0073] The common reflector may have a tricuspid shape.Advantageously, the tricuspid shape may facilitate efficient arrangement of the first transducer, the second transducer and the third transducer on an active surface of the at least one substrate.

[0074] In embodiments wherein the surface acoustic wave nebulizer comprises at least one absorber, the at least one absorber may be arranged to absorb the surface acoustic waves generated by the third transducer.

[0075] In an embodiment wherein at least one atomization zone comprises a first atomization zone, a second atomization zone, and a third atomization zone, at least one reflector may comprise a common absorber, wherein the first atomization zone is positioned between the common absorber and the first transducer, wherein the second atomization zone is positioned between the common absorber and the second transducer, and wherein the third atomization zone is positioned between the common absorber and the third transducer.

[0076] The common absorber may have a tricuspid shape. Advantageously, the tricuspid shape may facilitate efficient arrangement of the first transducer, the second transducer and the third transducer on an active surface of the at least one substrate.

[0077] The following preferred and optional features of the aerosol generator may apply to any of the aspects and embodiments described herein.

[0078] Each of the first transducer, the second transducer and the third transducer may comprise an interdigital transducer comprising a plurality of electrodes. Preferably, the plurality of electrodes are substantially parallel to each other. Preferably, the interdigital transducer comprises a first electrode array and a second electrode array interlaced with the first electrode array. Preferably, the first electrode array is substantially parallel to the second electrode array.

[0079] Each of the first transducer, the second transducer and the third transducer may be configured to generate a surface acoustic wave having a substantially linear wavefront.In embodiments where the transducer is an interdigital transducer comprising a plurality of electrodes, each electrode may be substantially linear.

[0080] Each of the first transducer, the second transducer, and the third transducer can be configured to generate a surface acoustic wave with a curved wave front. In an embodiment in which the transducer is an interdigital transducer comprising a plurality of electrodes, each electrode can be curved. The transducer can be configured to generate a surface acoustic wave with a convex wave front. Preferably, the transducer can be configured to generate a surface acoustic wave with a concave wave front. Advantageously, the concave wave front can provide a focusing effect. In other words, the concave wave front can focus the generated surface acoustic wave toward an atomization zone that is 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 atomization zone.

[0081] The substrate is formed of a substrate material. The substrate may be a piezoelectric 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, lithium titanate (BaTiO3) and lithium dioxide (LiNbO3). The ceramic may include lead zirconate titanate (PZT). The ceramic may include a doping material, for example, Ni, Bi, La, Nd or Nb ions. The substrate material may be polarized. The substrate material may be non-polarized. The substrate material may include both polarized and non-polarized materials.

[0082] The substrate may include a surface treatment. The surface treatment may be applied to an 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 an oily material. The coating may include an oily material.

[0083] According to a second aspect of the present disclosure, an aerosol generating device is provided according to any embodiment described herein, comprising an aerosol generator according to the first aspect of the present disclosure. The aerosol generating device also includes a power source, a first liquid storage portion and a second liquid storage portion. The first liquid storage portion is used to receive a first liquid aerosol-forming substrate, wherein the first supply element is arranged to supply the first liquid aerosol-forming substrate from the first liquid storage portion to at least one atomization zone. The second liquid storage portion is used to receive a second liquid aerosol-forming substrate, wherein the second supply element is arranged to supply the second liquid aerosol-forming substrate from the second liquid storage portion to at least one atomization zone.

[0084] In embodiments wherein the aerosol generator comprises a third transducer and a third supply element, the third supply element is arranged to supply a third liquid aerosol-forming substrate to the at least one atomization zone, preferably the aerosol generating device comprises a third liquid storage portion. Preferably, the third liquid storage portion is for receiving a third liquid aerosol-forming substrate, wherein the third supply element is arranged to supply the third liquid aerosol-forming substrate from the third liquid storage portion to the at least one atomization zone.

[0085] Each of the first liquid storage portion, the second liquid storage portion and the third liquid storage portion may be reusable. In other words, each liquid storage portion may be refilled by a user to replenish the liquid aerosol-forming substrate in at least one liquid storage portion. Each liquid storage portion may include a refilling orifice for inserting the liquid aerosol-forming substrate into the liquid storage portion. Each liquid storage portion may include a refilling valve between the refilling orifice and the liquid storage portion. Advantageously, the refilling valve may allow the liquid aerosol-forming substrate to flow through the refilling orifice into the liquid storage portion. Advantageously, the refilling valve may prevent the liquid aerosol-forming substrate from flowing out of the liquid storage portion through the refilling orifice.

[0086] Each of the first liquid storage portion, the second liquid storage portion and the third liquid storage portion may be replaceable. Each liquid storage portion is removable from the aerosol generating device. The aerosol generating device may comprise a cartridge, wherein the cartridge is removable from the aerosol generating device, and wherein the cartridge comprises the first liquid storage portion, the second liquid storage portion and the third liquid storage portion.

[0087] The aerosol generating device may comprise a first liquid aerosol-forming substrate contained within a first liquid storage portion.

[0088] The aerosol generating device may comprise a second liquid aerosol-forming substrate contained within a second liquid storage portion.

[0089] The aerosol generating device may comprise a third liquid aerosol-forming substrate contained within a third liquid storage portion.

[0090] At least one of the first liquid aerosol-forming substrate, the second liquid aerosol-forming substrate, and the third liquid aerosol-forming substrate may include nicotine. The nicotine containing liquid aerosol-forming substrate may be a nicotine salt substrate. The liquid aerosol-forming substrate may include plant-based materials. The liquid aerosol-forming substrate may include tobacco. The liquid aerosol-forming substrate may include homogenized tobacco materials. The liquid aerosol-forming substrate may include tobacco-free materials. The liquid aerosol-forming substrate may include homogenized plant-based materials.

[0091] At least one of the first liquid aerosol-forming substrate, the second liquid aerosol-forming substrate, and the third liquid aerosol-forming substrate may include at least one aerosol former. An aerosol former is any suitable known compound or mixture of compounds that helps to form a dense and stable aerosol in use. Suitable aerosol formers are well known in the art and include, but are not limited to: polyols, such as triethylene glycol, 1,3-butylene glycol, and glycerol; esters of polyols, such as glycerol mono-, di-, or triacetate; and fatty acid esters of mono-, di-, or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanoic acid. The aerosol former may be a polyol or a mixture thereof, for example, triethylene glycol, 1,3-butylene glycol, and glycerol. The liquid aerosol-forming substrate may include other additives and ingredients, such as flavoring agents.

[0092] At least one of the first liquid aerosol-forming substrate, the second liquid aerosol-forming substrate and the third liquid aerosol-forming substrate may comprise water.

[0093] At least one of the first liquid aerosol-forming substrate, the second liquid aerosol-forming substrate, and the third liquid aerosol-forming substrate may include nicotine and at least one aerosol former. The aerosol former may include glycerol. The aerosol former may include propylene glycol. The aerosol former may include both glycerol and propylene glycol. The liquid aerosol-forming substrate may have a nicotine concentration between about 0.1% and about 10%.

[0094] The controller may include a circuit connected to a power source and the first transducer, the second transducer, and the third transducer. The circuit may include a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, or an application specific integrated chip (ASIC) or other circuit capable of providing control. The circuit may include additional electronic components. The circuit may be configured to regulate the power supply from the power source to each of the first transducer, the second transducer, and the third transducer. The controller may be configured to continuously supply power to at least one of the first transducer, the second transducer, and the third transducer after the aerosol generating device is activated. The controller may be configured to intermittently supply power to at least one of the first transducer, the second transducer, and the third transducer. The controller may be configured to supply power to at least one of the first transducer, the second transducer, and the third transducer in succession.

[0095] Preferably, the controller and the power supply are configured to provide an alternating voltage to each of the first transducer, the second transducer, and the third transducer. 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 between about 20 megahertz and about 100 megahertz, more preferably between about 20 megahertz and about 80 megahertz. Advantageously, alternating voltages within these ranges can provide at least one of a desired aerosol generation rate and a desired droplet size.

[0096] The power supply can be any suitable type of power supply. The power supply can be a DC power supply. In some preferred embodiments, the power supply is a battery, such as a rechargeable lithium-ion battery. The power supply can be another form of charge storage device, such as a capacitor. The power supply may need to be recharged. The power supply can have a capacity that allows enough energy to be stored for one or more uses of the device. For example, the power supply can have enough capacity to allow continuous generation of aerosol for a period of about six minutes, corresponding to the typical time consumed by smoking a conventional cigarette, or for a period of a multiple of six minutes. In another example, the power supply can have enough capacity to allow the use of a predetermined number of times of the device or discontinuous activation. In one embodiment, the power supply is a DC power supply with a DC power supply voltage in the range of about 2.5 volts to about 4.5 volts and a DC power supply current in the range of about 1 ampere to about 10 amperes (corresponding to a DC power supply between about 2.5 watts to about 45 watts).

[0097] The aerosol generating device may advantageously comprise a DC / AC inverter, which may comprise a class C, class D or class E power amplifier.The DC / AC inverter may be arranged between the power supply and each of the first, second and third transducers.

[0098] The aerosol generating device may further comprise a DC / DC converter between the power supply and the DC / AC inverter.

[0099] 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 those materials, or thermoplastic materials suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. Preferably, the material is lightweight and non-brittle.

[0100] 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 at least one atomization zone of the aerosol generator. The device may include any number of air inlets. The device may include a plurality of air inlets.

[0101] The device housing may include an air outlet. The air outlet may be configured to enable air to exit the device housing for delivery to a user. The air outlet may be in fluid communication with at least one atomization zone of the aerosol generator. The aerosol generating device may include a mouthpiece. The mouthpiece may include an air outlet. The device may include any suitable number of air outlets. The device may include a plurality of air outlets. BRIEF DESCRIPTION OF THE DRAWINGS

[0102] The present invention will be further described, by way of example only, with reference to the accompanying drawings, in which:

[0103] Figure 1 shows a top view of an aerosol generator according to a first embodiment of the present disclosure;

[0104] Figure 2 Shown is a view taken along line 1-1 Figure 1 A cross-sectional view of an aerosol generator;

[0105] Figure 3 shows a top view of an aerosol generator according to a second embodiment of the present disclosure;

[0106] Figure 4 Shown is a view taken along line 3-3 Figure 3 A cross-sectional view of an aerosol generator;

[0107] Figure 5 Shown include Figure 3an aerosol generating device of an aerosol generator; and

[0108] Figure 6 A top view of an aerosol generator according to a third embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0109] Figure 1 and 2 An aerosol generator 100 according to a first embodiment of the present disclosure is shown. The aerosol generator 100 comprises a surface acoustic wave nebulizer 102, a first supply element 104 for supplying a first liquid aerosol-forming substrate to the surface acoustic wave nebulizer 102, and a second supply element 105 for supplying a second liquid aerosol-forming substrate to the surface acoustic wave nebulizer 102.

[0110] The surface acoustic wave atomizer 102 includes: a substrate 106 including a piezoelectric material sheet, a first transducer 108 arranged on an active surface 110 of the substrate 106, and a second transducer 109 arranged on the active surface 110 of the substrate 106. Each of the first transducer 108 and the second transducer 109 includes a first electrode array 112 and a second electrode array 114 interlaced with the first electrode array 112. The first electrode array 112 and the second electrode array 114 are curved and parallel to each other. During use, each of the first transducer 108 and the second transducer 109 generates a surface acoustic wave on the active surface 110 of the substrate 106. The curved shape of the first electrode array 112 and the second electrode array 114 results in a surface acoustic wave with a concave wave front. The concave wave front of the surface acoustic wave generated by the first transducer 108 is focused toward the first atomization area 116 on the active surface 110 of the substrate 106. The concave wavefront of the surface acoustic wave generated by the second transducer 109 is focused toward the second atomization region 117 on the active surface 110 of the substrate 106 .

[0111] The first supply element 104 includes a first channel 118 extending through the substrate 106 between a first inlet 120 at a passive surface 122 of the substrate 106 and a first outlet 124 at an active surface 110 of the substrate 106. The first outlet 124 is positioned in the first atomization region 116. The first supply element 104 also includes a first flow control element 130, which includes a micro pump. During use, the first liquid aerosol-forming substrate is supplied to the first atomization region 116 by the first flow control element 130 through the first channel 118, where it is atomized by the surface acoustic waves generated by the first transducer 108.

[0112] The second supply element 105 includes a second channel 119 extending through the substrate 106 between a second inlet 121 at the passive surface 122 of the substrate 106 and a second outlet 125 at the active surface 110 of the substrate 106. The second outlet 125 is positioned in the second atomization region 117. The second supply element 105 also includes a second flow control element 131, which includes a micro pump. During use, the second liquid aerosol-forming substrate is supplied to the second atomization region 117 by the second flow control element 131 through the second channel 119, where it is atomized by the surface acoustic waves generated by the second transducer 109.

[0113] The aerosol generator 100 further comprises a controller 132 arranged to control the first and second transducers 108, 109 and the first and second flow control elements 130, 131. Figure 1 In the illustrated embodiment, the controller 132 is positioned on the substrate 106 of the surface acoustic wave nebulizer 102 ; however, skilled artisans will recognize that the controller 132 may be provided separately from the surface acoustic wave nebulizer 102 .

[0114] The controller 132 is configured to provide a first drive signal to the first transducer 108 for generating surface acoustic waves on the active surface 110 of the substrate 106. The controller 132 is also configured to provide a first flow signal and a first stop signal to the first flow control element 130 to start and stop the flow of the first liquid aerosol-forming substrate through the first channel 118 and into the first atomization region 116. The controller 132 is configured to provide the first drive signal to the first transducer 108 only when the first flow control element 130 supplies the first liquid aerosol-forming substrate to the first atomization region 116.

[0115] The controller 132 is configured to provide a second drive signal to the second transducer 109 for generating surface acoustic waves on the active surface 110 of the substrate 106. The controller 132 is also configured to provide a second flow signal and a second stop signal to the second flow control element 131 to start and stop the flow of the second liquid aerosol-forming substrate through the second channel 119 and into the second atomization region 117. The controller 132 is configured to provide the second drive signal to the second transducer 109 only when the second flow control element 131 supplies the second liquid aerosol-forming substrate to the second atomization region 117.

[0116] Figure 3 and 4An aerosol generator 200 according to a second embodiment of the present disclosure is shown. The aerosol generator 200 comprises a surface acoustic wave nebulizer 202, a first supply element 204 for supplying a first liquid aerosol-forming substrate to the surface acoustic wave nebulizer 202, and a second supply element 205 for supplying a second liquid aerosol-forming substrate to the surface acoustic wave nebulizer 202.

[0117] The surface acoustic wave atomizer 202 includes a substrate 206 including a piezoelectric material sheet, a first transducer 208 disposed on an active surface 210 of the substrate 206, and a second transducer 209 disposed on the active surface 210 of the substrate 206. Each of the first transducer 208 and the second transducer 209 includes a Figure 1 The surface acoustic waves generated by the first transducer 208 and the second transducer 209 are focused toward the common atomization area 216.

[0118] The surface acoustic wave nebulizer 202 includes a common passage 240 extending from a common outlet 225 located within a common nebulization zone 216 at an active surface of the substrate 206 into the substrate 206 .

[0119] The first supply element 204 includes a first channel 218 extending from a first inlet 220 at a blunt surface 222 of the substrate 206 into the substrate 206. The first channel 218 is in fluid communication with a common channel 240. The first supply element 204 also includes a first flow control element 230, which includes a micropump. During use, the first liquid aerosol-forming substrate is supplied by the first flow control element 230 through the first channel 218 and the common channel 240 to the common atomization region 216, where it is atomized by the surface acoustic waves generated by the first transducer 208.

[0120] The second supply element 205 includes a second channel 219 extending from a second inlet 221 at a blunt surface 222 of the substrate 206 into the substrate 206. The second channel 219 is in fluid communication with the common channel 240. The second supply element 205 also includes a second flow control element 231, which includes a micro pump. During use, the second liquid aerosol-forming substrate is supplied to the common atomization region 216 by the second flow control element 231 through the second channel 219 and the common channel 240, where it is atomized by the surface acoustic waves generated by the second transducer 209.

[0121] The aerosol generator 200 further comprises a controller 232 arranged to control the first and second transducers 208, 209 and the first and second flow control elements 230, 231. Figure 4In the illustrated embodiment, the controller 232 is positioned on the substrate 206 of the surface acoustic wave nebulizer 202 ; however, skilled artisans will recognize that the controller 232 may be provided separately from the surface acoustic wave nebulizer 202 .

[0122] The controller 232 is configured to provide a first drive signal to the first transducer 208 for generating surface acoustic waves on the active surface 210 of the substrate 206. The controller 232 is also configured to provide a first flow signal and a first stop signal to the first flow control element 230 to start and stop the flow of the first liquid aerosol-forming substrate through the first channel 218 and the common channel 240 to the common atomization region 216. The controller 232 is configured to provide the first drive signal to the first transducer 208 only when the first flow control element 230 supplies the first liquid aerosol-forming substrate to the common atomization region 216.

[0123] The controller 232 is configured to provide a second drive signal to the second transducer 209 for generating surface acoustic waves on the active surface 210 of the substrate 206. The controller 232 is also configured to provide a second flow signal and a second stop signal to the second flow control element 231 to start and stop the flow of the second liquid aerosol-forming substrate through the second channel 219 and the common channel 240 to the common atomization region 216. The controller 232 is configured to provide the second drive signal to the second transducer 209 only when the second flow control element 231 supplies the second liquid aerosol-forming substrate to the common atomization region 216.

[0124] The controller 232 is configured to provide a second stop signal to the second flow control element 231 when the controller 232 provides a first flow signal to the first control element 230. The controller 232 is also configured to provide a first stop signal to the first flow control element 230 when the controller 232 provides a second flow signal to the second flow control element 231.

[0125] Figure 5 Shown include Figure 3 and 4 200. The aerosol generating device 300 further comprises a first liquid storage portion 302 containing a first liquid aerosol-forming substrate 304 and a second liquid storage portion 303 containing a second liquid aerosol-forming substrate 305. The first flow control element 230 of the aerosol generator 200 is arranged to supply the first liquid aerosol-forming substrate 304 from the first liquid storage portion 302 to the first inlet 220 of the aerosol generator 200. The second flow control element 231 of the aerosol generator 200 is arranged to supply the second liquid aerosol-forming substrate 305 from the second liquid storage portion 303 to the second inlet 221 of the aerosol generator 200.

[0126] The aerosol generating device 300 further comprises a power source 308 comprising a rechargeable battery for supplying power to the controller 232 , the first and second transducers 208 , 209 , and the first and second flow control elements 230 , 231 .

[0127] The aerosol generating device 300 also includes a housing 312 in which the aerosol generator 200, the first liquid storage portion 302 and the second liquid storage portion 303 and the power source 308 are housed. The housing 312 defines an air inlet 314, a mouthpiece 316 and an air outlet 318. During use, a user draws on the mouthpiece 316 to draw air from the air inlet 314 to the air outlet 318 through the housing 312. The aerosol generated by the aerosol generator 200 is entrained in the airflow through the housing 312 for delivery to the user.

[0128] Figure 6 FIG. 4 shows a top view of an aerosol generator 400 according to a third embodiment of the present disclosure. The aerosol generator 400 is similar to Figure 1 and Figure 2 The aerosol generator 100 of FIG. 4 is similar to the aerosol generator 100 of FIG. 4 , but includes an additional transducer, atomization zone, and supply element. A skilled person will recognize that the construction and operation of the aerosol generator 400 is otherwise similar to the construction and operation of the aerosol generator 400 .

[0129] The aerosol generator 400 includes a surface acoustic wave nebulizer 402, a first supply element 404 for supplying a first liquid aerosol-forming substrate to the surface acoustic wave nebulizer 402, a second supply element 405 for supplying a second liquid aerosol-forming substrate to the surface acoustic wave nebulizer 402, and a third supply element 454 for supplying a third liquid aerosol-forming substrate to the surface acoustic wave nebulizer 402.

[0130] The surface acoustic wave atomizer 402 includes a substrate 406 including a piezoelectric material sheet, a first transducer 408 disposed on an active surface 410 of the substrate 406, a second transducer 409 disposed on the active surface 410 of the substrate 406, and a third transducer 458 disposed on the active surface 410 of the substrate 406. Each of the first transducer 408, the second transducer 409, and the third transducer 458 includes a first transducer 408, a second transducer 409, and a third transducer 458. Figure 1 The first transducer 108 and the second transducer 109 are the first electrode array and the second electrode array. The surface acoustic waves generated by the first transducer 408 are focused toward the first atomization area 416. The surface acoustic waves generated by the second transducer 409 are focused toward the second atomization area 417. The surface acoustic waves generated by the third transducer 458 are focused toward the third atomization area 466.

[0131] The surface acoustic wave nebulizer 402 also includes a reflector 470 having a tricuspid shape and positioned between the first nebulization area 416, the second nebulization area 417, and the third nebulization area 466. The reflector 470 is arranged to reflect the surface acoustic wave generated by each of the first transducer 408, the second transducer 409, and the third transducer 458 toward the corresponding first nebulization area 416, the second nebulization area 417, and the third nebulization area 466. In an alternative embodiment, the reflector 470 may be replaced by an absorber.

[0132] The first supply element 404 includes a first channel 418, which extends through the substrate 406 between a first inlet at the passive surface of the substrate 406 and a first outlet at the active surface 410 of the substrate 406. The first outlet is positioned in the first atomization zone 416. The first supply element 404 also includes a first flow control element, which includes a micro pump. During use, the first liquid aerosol-forming substrate is supplied to the first atomization zone 416 by the first flow control element through the first channel 418, and in the first atomization zone, it is atomized by the surface acoustic waves generated by the first transducer 408.

[0133] The second supply element 405 includes a second channel 419 extending through the substrate 406 between a second inlet at the passive surface of the substrate 406 and a second outlet at the active surface 410 of the substrate 406. The second outlet is positioned in the second atomization region 417. The second supply element 405 also includes a second flow control element, which includes a micro pump. During use, the second liquid aerosol-forming substrate is supplied to the second atomization region 417 by the second flow control element through the second channel 419, where it is atomized by the surface acoustic waves generated by the second transducer 409.

[0134] The third supply element 454 includes a third channel 468, which extends through the substrate 406 between the third inlet at the passive surface of the substrate 406 and the third outlet at the active surface 410 of the substrate 406. The third outlet is positioned in the third atomization zone 466. The third supply element 454 also includes a third flow control element, which includes a micro pump. During use, the third liquid aerosol forms a substrate that is supplied to the third atomization zone 466 by the third channel 468 by the third flow control element, and in the third atomization zone, it is atomized by the surface acoustic wave generated by the third transducer 458.

[0135] The aerosol generator 400 further comprises a controller 432 arranged to control the first transducer 408, the second transducer 409 and the third transducer 458 and the first flow control element, the second flow control element and the third flow control element. Figure 6In the illustrated embodiment, the controller 432 is positioned on the substrate 406 of the surface acoustic wave nebulizer 402 ; however, skilled artisans will recognize that the controller 432 may be provided separately from the surface acoustic wave nebulizer 402 .

[0136] The controller 432 is configured to provide a first drive signal to the first transducer 408 for generating surface acoustic waves on the active surface 410 of the substrate 406. The controller 432 is also configured to provide a first flow signal and a first stop signal to the first flow control element to start and stop the flow of the first liquid aerosol-forming substrate through the first channel 418 and into the first atomization region 416. The controller 432 is configured to provide the first drive signal to the first transducer 408 only when the first flow control element supplies the first liquid aerosol-forming substrate to the first atomization region 416.

[0137] The controller 432 is configured to provide a second drive signal to the second transducer 409 for generating surface acoustic waves on the active surface 410 of the substrate 406. The controller 432 is also configured to provide a second flow signal and a second stop signal to the second flow control element to start and stop the flow of the second liquid aerosol-forming substrate through the second channel 419 and into the second atomization region 417. The controller 432 is configured to provide the second drive signal to the second transducer 409 only when the second flow control element supplies the second liquid aerosol-forming substrate to the second atomization region 417.

[0138] The controller 432 is configured to provide a third drive signal to the third transducer 458 for generating surface acoustic waves on the active surface 410 of the substrate 406. The controller 432 is also configured to provide a third flow signal and a third stop signal to the third flow control element to start and stop the flow of the third liquid aerosol-forming substrate through the third channel 468 and into the third atomization region 466. The controller 432 is configured to provide the third drive signal to the third transducer 458 only when the third flow control element supplies the third liquid aerosol-forming substrate to the third atomization region 466.

Claims

1. An aerosol generator for an aerosol generating device, the aerosol generator comprising: A surface acoustic wave atomizer, comprising: at least one substrate including an active surface defining at least one atomization zone; a first transducer positioned on an active surface of the at least one substrate; and a second transducer positioned on an active surface of the at least one substrate; a first supply element arranged to supply a first liquid aerosol-forming substrate to the at least one atomization region; a second supply element arranged to supply a second liquid aerosol-forming substrate to the at least one atomisation region; and A controller, wherein the controller is configured to provide a first drive signal to the first transducer for generating surface acoustic waves on the active surface of the at least one substrate to atomize the first liquid aerosol-forming substrate, wherein the controller is configured to provide a second drive signal to the second transducer for generating surface acoustic waves on the active surface of the at least one substrate to atomize the second liquid aerosol-forming substrate, wherein the controller is configured to provide the first drive signal to the first transducer only when the first liquid aerosol-forming substrate is supplied to the at least one atomization zone by the first supply element, and wherein the controller is configured to provide the second drive signal to the second transducer only when the second liquid aerosol-forming substrate is supplied to the at least one atomization zone by the second supply element.

2. The aerosol generator of claim 1, wherein the at least one substrate comprises a common substrate on which the first transducer and the second transducer are positioned.

3. An aerosol generator according to claim 2, wherein the at least one atomization zone is a common atomization zone defined by the common substrate, and wherein the aerosol generator further comprises a common supply element, which provides fluid communication between the common atomization zone and each of the first supply element and the second supply element.

4. An aerosol generator according to claim 3, wherein the first supply element includes a first flow control element, the first flow control element is arranged to control the flow of the first liquid aerosol-forming substrate to the common atomization area, wherein the second supply element includes a second flow control element, the second flow control element is arranged to control the flow of the second liquid aerosol-forming substrate to the common atomization area, wherein the controller is configured to provide a first flow signal to the first flow control element so that the first liquid aerosol-forming substrate can flow to the common atomization area, wherein the controller is configured to provide a second flow signal to the second flow control element so that the second liquid aerosol-forming substrate can flow to the common atomization area, wherein the controller is configured to provide a first stop signal to the first flow control element to deactivate the flow of the first liquid aerosol-forming substrate when the controller provides the second flow signal to the second flow control element, and wherein the controller is configured to provide a second stop signal to the second flow control element to deactivate the flow of the second liquid aerosol-forming substrate when the controller provides the first flow signal to the first flow control element.

5. An aerosol generator according to claim 1 or claim 2, wherein the at least one atomization zone includes a first atomization zone positioned on the active surface to receive surface acoustic waves generated by the first transducer and a second atomization zone positioned on the active surface to receive surface acoustic waves generated by the second transducer, wherein the first supply element is arranged to supply the first liquid aerosol-forming substrate to the first atomization zone, and wherein the second supply element is arranged to supply the second liquid aerosol-forming substrate to the second atomization zone.

6. An aerosol generator according to claim 5, wherein the controller is configured to provide the first drive signal to the first transducer only when the first liquid aerosol-forming substrate is supplied to the first atomization zone by the first supply element, and wherein the controller is configured to provide the second drive signal to the second transducer only when the second liquid aerosol-forming substrate is supplied to the second atomization zone by the second supply element.

7. The aerosol generator of claim 5, further comprising at least one reflector positioned on the active surface of the substrate to reflect surface acoustic waves generated by at least one of the first transducer and the second transducer.

8. An aerosol generator according to claim 7, wherein the at least one reflector comprises a common reflector, wherein the first atomization zone is positioned between the common reflector and the first transducer, and wherein the second atomization zone is positioned between the common reflector and the second transducer.

9. The aerosol generator of claim 5, further comprising at least one absorber positioned on the active surface of the substrate to absorb surface acoustic waves generated by at least one of the first transducer and the second transducer.

10. The aerosol generator of claim 9, wherein the at least one absorber comprises a common absorber, wherein the first atomization zone is positioned between the common absorber and the first transducer, and wherein the second atomization zone is positioned between the common absorber and the second transducer.

11. The aerosol generator according to any one of claims 1 to 4, further comprising: a third transducer positioned on an active surface of the at least one substrate; as well as a third supply element arranged to supply a third liquid aerosol-forming substrate to the at least one atomisation region; wherein the controller is configured to provide a third drive signal to the third transducer for generating surface acoustic waves on the active surface of the at least one substrate, wherein the controller is configured to provide the third drive signal to the third transducer only when the third liquid aerosol-forming substrate is supplied to the at least one atomization zone by the third supply element.

12. An aerosol generator according to claim 11, wherein the at least one atomization zone includes a first atomization zone positioned on the active surface to receive surface acoustic waves generated by the first transducer, a second atomization zone positioned on the active surface to receive surface acoustic waves generated by the second transducer, and a third atomization zone positioned on the active surface to receive surface acoustic waves generated by the third transducer, wherein the first supply element is arranged to supply the first liquid aerosol-forming substrate to the first atomization zone, wherein the second supply element is arranged to supply the second liquid aerosol-forming substrate to the second atomization zone, and wherein the third supply element is arranged to supply the third liquid aerosol-forming substrate to the third atomization zone.

13. The aerosol generator according to claim 12 further comprises a reflector positioned on the active surface of the substrate to reflect surface acoustic waves generated by each of the first transducer, the second transducer and the third transducer, wherein the first atomization zone is positioned between the reflector and the first transducer, wherein the second atomization zone is positioned between the reflector and the second transducer, and wherein the third atomization zone is positioned between the reflector and the third transducer.

14. The aerosol generator according to claim 12 further comprises an absorber positioned on the active surface of the substrate to absorb surface acoustic waves generated by each of the first transducer, the second transducer and the third transducer, wherein the first atomization zone is positioned between the absorber and the first transducer, wherein the second atomization zone is positioned between the absorber and the second transducer, and wherein the third atomization zone is positioned between the absorber and the third transducer.

15. The aerosol generator of claim 13, wherein the reflector has a tricuspid shape.

16. The aerosol generator of claim 14, wherein the absorber has a tricuspid shape.

17. An aerosol generating device comprising: An aerosol generator according to any one of claims 1 to 16; power supply; a first liquid storage portion for receiving the first liquid aerosol-forming substrate, wherein the first supply element is arranged to supply the first liquid aerosol-forming substrate from the first liquid storage portion to the at least one atomisation region; as well as a second liquid storage portion for receiving the second liquid aerosol-forming substrate, wherein the second supply element is arranged to supply the second liquid aerosol-forming substrate from the second liquid storage portion to the at least one atomisation region.

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