Aerosol generator comprising supply element

Abstract

To provide an aerosol-generator for an aerosol-generating device.SOLUTION: An aerosol generator 100 includes a surface acoustic wave atomizer 102 and a supply element 104. The surface acoustic wave atomizer includes: a substrate 106 including an active surface 110 defining at least one atomization region 116; and at least one transducer 108 positioned on the active surface to generate surface acoustic waves on the active surface. The supply element is arranged to supply a liquid aerosol-forming substrate to the at least one atomization region, and includes a channel 118 extending through the substrate between an inlet to receive a supply of the liquid aerosol-forming substrate and an outlet positioned within the at least one atomization region of the active surface of the substrate. The channel has at least one of a cross-sectional area that varies in a direction from the inlet to the outlet and a portion that extends in a non-perpendicular direction with respect to the active surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to aerosol generators for aerosol generating devices, each of which includes a surface acoustic wave atomizer and a supply element. The present disclosure also relates to aerosol generating devices that include the aerosol generator. [Background technology]

[0002] Aerosol-generating systems in which the aerosol-forming substrate is heated rather than combusted are well known in the art. Typically, in such aerosol-generating systems, the aerosol is generated by the transfer of energy from an 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 a consistent user experience for users of aerosol generating devices. However, known aerosol generating devices may provide insufficient control over the rate at which a liquid aerosol-forming substrate is supplied to an aerosol generator, such as a heater. Known aerosol generating devices may also provide insufficient control over the rate at which the aerosol generator vaporizes the liquid aerosol-forming substrate. Both of these shortcomings of known aerosol generating devices may result in an inconsistent user experience. Summary of the Invention [Problem to be solved by the invention]

[0004] It would be desirable to provide an aerosol generator for an aerosol generating device that offers improved control of the rate at which a liquid aerosol-forming substrate is delivered to the atomization region of the aerosol generating device.

[0005] It would be desirable to provide an aerosol generator for an aerosol generating device that offers improved control of the rate at which a liquid aerosol-forming substrate is atomized from the atomization region of the aerosol generating device. [Means for solving the problem]

[0006] According to a first aspect of the present disclosure, there is provided an aerosol generator for an aerosol generating device, the aerosol generator comprising a surface acoustic wave atomizer and a supply element. The surface acoustic wave atomizer comprises a substrate having an active surface defining at least one atomization region. The surface acoustic wave atomizer also comprises at least one transducer positioned on the active surface of the substrate for generating surface acoustic waves on the active surface of the substrate. The supply element is arranged to supply a liquid aerosol-forming substrate to the at least one atomization region of the surface acoustic wave atomizer. The supply element comprises a channel extending through the substrate between an inlet for receiving a supply of the liquid aerosol-forming substrate and an outlet positioned within the at least one atomization region of the active surface of the substrate. The channel has at least one of a cross-sectional area that varies in a direction from the inlet to the outlet and a portion that extends in a direction non-perpendicular to the active surface.

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

[0008] Advantageously, using a surface acoustic wave atomizer to atomize a liquid aerosol-forming substrate provides improved control of the atomization 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 consistent amount of atomized liquid aerosol-forming substrate.

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

[0010] Advantageously, the channels of the feed element of the aerosol generator according to the present disclosure facilitate improved control of the rate at which the liquid aerosol-forming substrate is fed to at least one atomizer region of the surface acoustic wave atomizer. In particular, the channels of the feed element facilitate improved control of the flow rate of the liquid aerosol-forming substrate compared to known liquid transfer elements such as capillary wicks. For example, one or more dimensions of the channel may be selected to provide a desired volumetric flow rate of the liquid aerosol-forming substrate through the channel.

[0011] Advantageously, the varying cross-sectional area of ​​the channel may facilitate providing both a desired flow rate of the liquid aerosol-forming substrate through the channel and at least one of a desired size and shape of the channel at an outlet positioned within the at least one atomization region. The desired size or shape of the channel at the outlet may be selected to increase or optimize the transfer of energy from surface acoustic waves generated by the surface acoustic wave atomizer to the liquid aerosol-forming substrate in the at least one atomization region.

[0012] Advantageously, the portion of the channel that extends non-perpendicularly to the active surface may provide increased mechanical stability for the substrate at the outlet.

[0013] At least a portion of the channel may have a substantially straight cross-sectional shape. In embodiments where the channel has a portion that extends non-perpendicularly relative to the active surface, the substantially straight portion of the channel preferably extends non-perpendicularly relative to the active surface. The substantially straight portion of the channel preferably slopes towards the at least one transducer.

[0014] In embodiments in which the channel has a cross-sectional area that varies from the inlet to the outlet, at least a portion of the channel preferably has an increasing cross-sectional area from the inlet to the outlet. Advantageously, a channel having an increasing cross-sectional area from the inlet to the outlet may increase or optimize the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate in at least one atomization region. Preferably, at least a portion of the channel having an increasing cross-sectional area from the inlet to the outlet is near the outlet.

[0015] The channel may comprise a first portion defining a minimum cross-sectional area of ​​the channel to determine the flow rate of the liquid aerosol-forming substrate through the channel. The first portion preferably extends from the inlet. The channel may comprise a second portion having a different cross-sectional area compared to the first portion. The second portion preferably has a larger cross-sectional area than the first portion. The second portion preferably extends between the first portion and the outlet. The second portion preferably has a cross-sectional area that increases in the direction from the inlet to the outlet.

[0016] At least a portion of the channel may have a funnel, cone or wedge shape. Preferably, at least a portion of the channel having a funnel, cone or wedge shape is near the outlet.

[0017] In embodiments in which at least a portion of the channel has a funnel shape, the funnel shape may comprise a first portion having a substantially constant cross-sectional area extending from the inlet and a second portion extending between the first portion and the outlet, the second portion having a cross-sectional area that increases in a direction from the inlet to the outlet. The second portion may have a conical shape. The second portion may have a frusto-conical shape. The conical shape of the second portion may be a right cone shape. The conical shape of the second portion may be a curved-sided cone shape.

[0018] In embodiments in which at least a portion of the channel has a conical shape, the conical shape may be a frusto-conical shape. A truncated end of the conical shape may define the entrance. The conical shape may be a right circular cone. The conical shape may be a curved-sided cone.

[0019] Preferably, at least a portion of the channel is curved. Advantageously, the curved portion of the channel may facilitate the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate in at least one atomization region.

[0020] At least a portion of the channel at the outlet is preferably curved to form a continuous transition between the channel and the active surface of the substrate.

[0021] Preferably, at least a portion of the channel at the outlet extends tangentially to the active surface of the substrate. Advantageously, the tangentially extending portion of the channel at the outlet may facilitate the formation of a thin film of the liquid aerosol-forming substrate within at least one atomization region on the active surface of the substrate. Advantageously, the thin film of the liquid aerosol-forming substrate facilitates aerosolization of the liquid aerosol-forming substrate by surface acoustic waves generated by the surface acoustic wave atomizer.

[0022] The outlet may have a first side and a second side opposite the first side, the first side being positioned between the second side and the at least one transducer. The channel may have a first outlet portion on the first side of the outlet and a second outlet portion on the second side of the outlet, the first outlet portion extending tangentially to the active surface and the second outlet portion extending perpendicularly to the active surface.

[0023] Advantageously, the first outlet portion extending tangentially to the active surface may increase or optimize the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate in the at least one atomization region.

[0024] Advantageously, the first outlet portion extending tangentially to the active surface may facilitate the formation of a thin film of the liquid aerosol-forming substrate within at least one atomization region on the active surface of the substrate. Advantageously, the thin film of the liquid aerosol-forming substrate facilitates aerosolization of the liquid aerosol-forming substrate by surface acoustic waves generated by the surface acoustic wave atomizer.

[0025] Advantageously, the second outlet portion extending perpendicular to the active surface may function as a reflector to reflect the surface acoustic waves toward the at least one atomization region. Advantageously, reflecting the surface acoustic waves toward the at least one atomization region may reduce or minimize the power input required for the at least one transducer. In other words, using a reflector to reflect the surface acoustic waves toward the at least one atomization region may increase the efficiency of the surface acoustic wave atomizer.

[0026] The substrate may define a recess in the active surface of the substrate. Preferably, the recess extends between the at least one transducer and the outlet. Preferably, the at least one transducer and the outlet are both positioned within the recess. The substrate may include a wall at least partially defining the recess, the wall extending perpendicular to the active surface. Preferably, the wall is positioned to reflect surface acoustic waves from the at least one transducer towards the outlet.

[0027] Preferably, the channel has a minimum cross-sectional area. The term "minimum cross-sectional area" is used herein to refer to the narrowest portion of the channel. The minimum cross-sectional area of ​​the channel at least partially determines the flow rate of the liquid aerosol-forming substrate along the channel. The channel has a minimum cross-sectional area of ​​at least about 8×10 -3 It is preferred to have a minimum cross-sectional area of ​​square millimeters.

[0028] The supply element may comprise a single channel, in other words the channel may be the only channel of the supply element.

[0029] The supply element may comprise a plurality of channels. The channel may be a first channel, and the supply element may comprise at least one additional channel extending through the substrate.

[0030] The inlet may be a first inlet and the outlet may be a first outlet, and the supply element comprises at least one additional inlet for receiving a supply of liquid aerosol-forming substrate and at least one additional outlet positioned within at least one atomization region of the active surface of the substrate. Preferably, each of the at least one additional channel extends between one of the additional inlets and one of the additional outlets. Preferably, each of the at least one additional channel has a cross-sectional area that varies in a direction from the respective additional inlet to the respective additional outlet.

[0031] Each of the at least one additional channel may comprise any of the optional and preferred features described herein with respect to the first channel.

[0032] Each of the channels, inlets, and outlets may be formed in the substrate using any suitable manufacturing process, including mechanical drilling, mechanical grinding (e.g., abrasive blasting using at least one of sand and water), laser ablation, laser drilling, etching (e.g., reactive ion etching), and combinations thereof.

[0033] According to a second aspect of the present disclosure, there is provided an aerosol generator for an aerosol generating device, the aerosol generator comprising a surface acoustic wave atomizer and a supply element. The surface acoustic wave atomizer comprises a substrate having an active surface defining at least one atomization region. The surface acoustic wave atomizer also comprises at least one transducer positioned on the active surface of the substrate for generating surface acoustic waves on the active surface of the substrate. The supply element is arranged to supply a liquid aerosol-forming substrate to the at least one atomization region of the surface acoustic wave atomizer. The supply element comprises a plurality of interconnected channels extending through the substrate between at least one inlet for receiving a supply of the at least one liquid aerosol-forming substrate and at least one outlet positioned within the at least one atomization region of the active surface of the substrate.

[0034] Advantageously, using a surface acoustic wave atomizer to atomize a liquid aerosol-forming substrate provides improved control of the atomization 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 consistent amount of atomized liquid aerosol-forming substrate.

[0035] Advantageously, the power required by a surface acoustic wave atomizer to atomize a liquid aerosol-forming substrate is less than the power required to atomize the same amount of liquid aerosol-forming substrate using known aerosol generators such as electric heaters.

[0036] Advantageously, the multiple interconnected channels of the feed element of the aerosol generator according to the present disclosure facilitate improved control of the rate at which the liquid aerosol-forming substrate is fed to at least one atomizer region of the surface acoustic wave atomizer. In particular, the multiple interconnected channels of the feed element facilitate improved control of the flow rate of the liquid aerosol-forming substrate compared to known liquid transfer elements such as capillary wicks. For example, one or more dimensions of the multiple interconnected channels may be selected to provide a desired volumetric flow rate of the liquid aerosol-forming substrate through the multiple interconnected channels.

[0037] Advantageously, multiple interconnected channels may facilitate supplying a single liquid aerosol-forming substrate to multiple outlets within at least one atomization region.

[0038] Advantageously, the plurality of interconnected channels may facilitate mixing of two or more liquid aerosol-forming substrates by the supply element. Advantageously, mixing of two or more liquid aerosol-forming substrates by the supply element enables the mixed liquid aerosol-forming substrate to be provided to at least one atomization region. Advantageously, mixing of two or more liquid aerosol-forming substrates by the supply element facilitates separate storage of the two or more liquid aerosol-forming substrates and mixing of the two or more liquid aerosol-forming substrates only during use.

[0039] The at least one inlet may comprise a single inlet, and the at least one outlet may comprise multiple outlets, with the multiple interconnected channels providing fluid communication between the inlet and each of the multiple outlets. Advantageously, the single inlet and multiple outlets may facilitate supplying a single liquid aerosol-forming substrate to multiple locations within the at least one atomization region. Advantageously, the multiple outlets may facilitate uniform distribution of the liquid aerosol-forming substrate across the at least one atomization region.

[0040] The plurality of outlets may comprise at least two outlets, at least three outlets, at least four outlets, or at least five outlets.

[0041] The plurality of outlets may comprise 20 or fewer outlets, 18 or fewer outlets, 16 or fewer outlets, 14 or fewer outlets, 12 or fewer outlets, or 10 or fewer outlets.

[0042] The multiple outlets may be positioned within the at least one atomization region in any suitable arrangement.

[0043] The multiple outlets may be randomly positioned within the at least one atomization region.

[0044] The plurality of outlets may be arranged in a pattern within the at least one atomization region. The plurality of outlets may be arranged symmetrically within the at least one atomization region. The plurality of outlets may be arranged in one or more rows. The plurality of outlets may be arranged in at least one of a grid, a spiral, and one or more concentric circles.

[0045] The at least one outlet may comprise a single outlet, and the at least one inlet may comprise a plurality of inlets, with the plurality of interconnected channels providing fluid communication between the outlet and each of the plurality of inlets. Advantageously, the single outlet and the plurality of inlets may facilitate mixing of two or more liquid aerosol-forming substrates via the plurality of interconnected channels.

[0046] The plurality of inlets may comprise at least two inlets, at least three inlets, at least four inlets, or at least five inlets.

[0047] The plurality of inlets may comprise 20 inlets or less, 18 inlets or less, 16 inlets or less, 14 inlets or less, 12 inlets or less, or 10 inlets or less.

[0048] The multiple inlets may be positioned on the surface of the substrate in any suitable arrangement.

[0049] The multiple inlets may be randomly positioned on the surface of the substrate.

[0050] The plurality of inlets may be arranged in a pattern on the surface of the substrate. The plurality of inlets may be arranged symmetrically on the surface of the substrate. The plurality of inlets may be arranged in one or more rows. The plurality of inlets may be arranged in at least one of a grid, a spiral, and one or more concentric circles.

[0051] Each of the at least one inlet has at least about 8×10 -3 It preferably has a cross-sectional area of ​​square millimeters.

[0052] The at least one inlet, the at least one outlet, and each of the plurality of interconnected channels may be formed in the substrate using any suitable manufacturing process, including mechanical drilling, mechanical grinding, laser ablation, laser drilling, etching (e.g., reactive ion etching), and combinations thereof.

[0053] According to a third aspect of the present disclosure, an aerosol generator for an aerosol generating device is provided, the aerosol generator comprising a surface acoustic wave atomizer and a supply element. The surface acoustic wave atomizer comprises a substrate having an active surface defining at least one atomization region. The surface acoustic wave atomizer also comprises at least one transducer positioned on the active surface of the substrate for generating surface acoustic waves on the active surface of the substrate. The supply element is arranged to supply a liquid aerosol-forming substrate to the at least one atomization region of the surface acoustic wave atomizer. The supply element comprises at least one channel extending through the substrate between at least one inlet for receiving a supply of the liquid aerosol-forming substrate and at least one outlet positioned within the at least one atomization region of the active surface of the substrate. The substrate is a laminate material comprising multiple layers of substrate material. At least one of the layers of substrate material defines at least one outlet, at least one of the layers of substrate material defines at least one inlet, and at least one of the layers of substrate material defines at least one channel.

[0054] Advantageously, forming the substrate from multiple layers of substrate material that define at least one inlet, at least one outlet, and at least one channel may facilitate the formation of channels having non-linear shapes.

[0055] Preferably, at least two of the layers of substrate material define at least one channel. Advantageously, defining the at least one channel with multiple layers of substrate material may further facilitate forming channels having non-linear shapes. Preferably, the at least two layers of substrate material comprise a first layer of substrate material defining a first portion of the at least one channel and a second layer of substrate material defining a second portion of the at least one channel.

[0056] The multiple layers of substrate material may be secured together by at least one of bonding, clamping, and one or more adhesives.

[0057] The aerosol generator according to the third aspect of the present disclosure may be the aerosol generator according to the first aspect of the present disclosure or the aerosol generator according to the second aspect of the present disclosure.

[0058] The following preferred optional features of the aerosol generator may be applied to the aerosol generator according to the first, second and third aspects of the present disclosure.

[0059] At least one transducer may comprise an interdigital transducer comprising a plurality of electrodes, preferably substantially parallel to one another. Preferably, the interdigital transducer comprises a first array of electrodes and a second array of electrodes interleaved with the first array of electrodes. Preferably, the first array of electrodes is substantially parallel to the second array of electrodes.

[0060] The 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 multiple electrodes, each electrode may be substantially linear.

[0061] The transducer may be configured to generate surface acoustic waves having a curved wavefront. In embodiments where the transducer is an interdigital transducer comprising multiple electrodes, each electrode may be curved. The transducer may be configured to generate surface acoustic waves having a convex wavefront. Preferably, the transducer may be configured to generate surface acoustic waves having a concave wavefront. Advantageously, a concave wavefront may provide a focusing effect. In other words, a concave wavefront may focus the generated surface acoustic waves toward an atomization region that is smaller than the transducer. Advantageously, focusing the generated surface acoustic waves may increase the rate at which energy is delivered to the liquid aerosol-forming substrate in the atomization region.

[0062] The at least one transducer may be a single transducer. The at least one transducer may be multiple transducers. In embodiments in which the surface acoustic wave atomizer includes multiple transducers, each transducer is preferably disposed on the active surface of the substrate such that surface acoustic waves generated by the transducer propagate toward at least one atomization region.

[0063] The surface acoustic wave atomizer may include at least one reflector, preferably located on the active surface of the substrate. The at least one reflector is preferably arranged to reflect surface acoustic waves from the at least one transducer toward the at least one atomization region. Advantageously, a reflector arranged to reflect surface acoustic waves toward the at least one atomization region may increase or maximize the efficiency of the surface acoustic wave atomizer.

[0064] At least one reflector may comprise one or more electrodes.

[0065] The at least one reflector may comprise one or more metal portions positioned on the active surface of the substrate. Each metal portion may have a linear shape. Each metal portion may have a curved shape. The at least one reflector may comprise a plurality of metal portions. The plurality of metal portions may be arranged in a pattern on the active surface of the substrate. Preferably, each metal portion is substantially parallel to an adjacent metal portion forming the at least one reflector.

[0066] A portion of the substrate may form at least a portion of the at least one reflector. The substrate may define at least one protrusion, the at least one protrusion forming at least a portion of the at least one reflector. The substrate may define at least one recess, the at least one recess forming at least a portion of the at least one reflector.

[0067] The at least one atomization region may be positioned between the at least one transducer and the at least one reflector.

[0068] The at least one reflector may be a single reflector. The at least one reflector may be a plurality of reflectors.

[0069] In embodiments where the surface acoustic wave atomizer includes multiple transducers, the at least one reflector may be multiple reflectors, each of which may be positioned opposite one of the reflectors such that at least one atomization region is positioned between the transducer and the corresponding reflector.

[0070] The substrate is formed from 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, 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 poled. The substrate material may not be poled. The substrate material may include both polarized and non-polarized materials.

[0071] 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 oleophobic material. The coating may include an oleophilic material.

[0072] According to a fourth aspect of the present disclosure, there is provided an aerosol generation device comprising the aerosol generator according to the first, second or third aspect of the present disclosure, The aerosol generation device also comprises a controller for controlling the at least one transducer, a power source and at least one liquid storage portion for receiving a liquid aerosol-forming substrate, the supply element being arranged to supply the liquid aerosol-forming substrate from the at least one liquid storage portion to the at least one atomization region.

[0073] The at least one liquid storage portion may be reusable. In other words, the at least one liquid storage portion may be refillable by a user to replenish the liquid aerosol-forming substrate in the at least one liquid storage portion. The at least one liquid storage portion may include a refill opening for inserting the liquid aerosol-forming substrate into the liquid storage portion. The at least one liquid storage portion may include a refill valve between the refill opening and the at least one liquid storage portion. Advantageously, the refill valve may allow the liquid aerosol-forming substrate to flow into the at least one liquid storage portion through the refill opening. Advantageously, the refill valve may prevent the liquid aerosol-forming substrate from flowing out of the at least one liquid storage portion through the refill opening.

[0074] The at least one liquid reservoir may be replaceable. The at least one liquid reservoir may be removable from the aerosol generation device. The aerosol generation device may comprise a cartridge, the cartridge being removable from the aerosol generation device and comprising the at least one liquid reservoir.

[0075] The aerosol generating device may comprise a liquid aerosol-forming substrate contained within at least one liquid reservoir.

[0076] The liquid aerosol-forming substrate may comprise nicotine. The nicotine-containing liquid aerosol-forming substrate may be a nicotine salt matrix. The liquid aerosol-forming substrate may comprise a plant-derived material. The liquid aerosol-forming substrate may comprise tobacco. The liquid aerosol-forming substrate may comprise a homogenized tobacco material. The liquid aerosol-forming substrate may comprise a non-tobacco-containing material. The liquid aerosol-forming substrate may comprise a homogenized plant-derived material.

[0077] The liquid aerosol-forming substrate may contain at least one aerosol former. The aerosol former is any suitable, well-known compound or mixture of compounds that facilitates the formation of a dense, stable aerosol upon use. Suitable aerosol formers are well-known in the art and include, but are not limited to, polyhydric alcohols (e.g., triethylene glycol, 1,3-butanediol, glycerin), esters of polyhydric alcohols (e.g., glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic, dicarboxylic, or polycarboxylic acids (e.g., dimethyl dodecanedioate, dimethyl tetradecanedioate). The aerosol former may be a polyhydric alcohol or a mixture thereof (e.g., triethylene glycol, 1,3-butanediol, and glycerin). The liquid aerosol-forming substrate may contain other additives and ingredients (e.g., flavoring agents).

[0078] The liquid aerosol-forming substrate may comprise water.

[0079] The liquid aerosol-forming substrate may include nicotine and at least one aerosol former. The aerosol former may include glycerin. The aerosol former may include propylene glycol. The aerosol former may include both glycerin and propylene glycol. The liquid aerosol-forming substrate may have a nicotine concentration of about 0.1 percent to about 10 percent.

[0080] In embodiments in which the inlet of the supply element comprises multiple inlets, the at least one liquid reservoir may comprise a first liquid reservoir for receiving a first liquid aerosol-forming substrate, the first liquid reservoir being in fluid communication with a first inlet of the multiple inlets, and a second liquid reservoir for receiving a second liquid aerosol-forming substrate, the second liquid reservoir being in fluid communication with a second inlet of the multiple inlets.

[0081] The aerosol generating device may comprise a flow control element arranged to control the flow rate of the liquid aerosol-forming substrate from the at least one liquid reservoir into the channel of the supply element.

[0082] The 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.

[0083] The flow control element may include at least one active element, which may include at least one of a micropump, a syringe pump, a piston pump, and an electroosmotic pump. The controller is preferably 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 the at least one liquid reservoir to the channel of the supply element.

[0084] The controller may comprise an electrical circuit connected to the power source and the at least one transducer. The electrical circuit may comprise a microprocessor. The microprocessor may be a programmable microprocessor, a microcontroller, or an application specific integrated chip (ASIC), or other electronic circuit capable of providing control. The electrical circuit may comprise additional electronic components. The electrical circuit may be configured to regulate the supply of power from the power source to the at least one transducer. The controller may be configured to continuously supply power to the at least one transducer after activation of the aerosol generating device. The controller may be configured to intermittently supply power to the at least one transducer. The controller may be configured to supply power to the at least one transducer with every puff.

[0085] The controller and power supply are preferably configured to provide an AC voltage to the at least one transducer. The AC voltage is preferably a radio frequency AC voltage. The AC voltage preferably has a frequency of at least about 20 megahertz. The AC voltage preferably has a frequency of about 20 megahertz to about 100 megahertz, more preferably about 20 megahertz to about 80 megahertz. Advantageously, AC voltages within these ranges may provide at least one of a desired rate of aerosol generation and a desired droplet size.

[0086] 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 also 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 the storage of sufficient energy 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 approximately 6 minutes, or a multiple of 6 minutes, corresponding to the typical time it takes to smoke a 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 range of about 2.5 watts to about 45 watts).

[0087] 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 disposed between the power source and the at least one transducer.

[0088] The aerosol generating device may further include a DC / DC converter between the power supply and the DC / AC inverter.

[0089] The aerosol generating device may include a device housing. The device housing may be elongated. The device housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composites containing one or more of these materials, or thermoplastics suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), or polyethylene. Preferably, the material is lightweight and not brittle.

[0090] 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 region of the aerosol generator. The device may include any suitable number of air inlets. The device may include multiple air inlets.

[0091] 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 a user. The air outlet may be in fluid communication with at least one atomization region 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 multiple air outlets.

[0092] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0093] [Figure 1] FIG. 1 shows a top view of an aerosol generator according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 shows a cross-sectional view of the aerosol generator of FIG. 1 taken along line 1-1. [Figure 3] FIG. 3 shows a perspective view of the channel of the aerosol generator of FIG. [Figure 4] FIG. 4 shows a top view of an aerosol generator according to a second embodiment of the present disclosure. [Figure 5] FIG. 5 shows a cross-sectional view of the aerosol generator of FIG. 4 taken along line 4-4. [Figure 6] FIG. 6 shows a perspective view of the channels of the aerosol generator of FIG. [Figure 7] FIG. 7 shows a top view of an aerosol generator according to a third embodiment of the present disclosure. [Figure 8] FIG. 8 shows a cross-sectional view of the aerosol generator of FIG. 7 taken along line 7-7. [Figure 9] FIG. 9 shows a perspective view of the channels of the aerosol generator of FIG. [Figure 10] FIG. 10 shows a first variant of the aerosol generator of FIG. [Figure 11] FIG. 11 shows a second variant of the aerosol generator of FIG. [Figure 12] FIG. 12 shows a top view of an aerosol generator according to a fourth embodiment of the present disclosure. [Figure 13] FIG. 13 shows a cross-sectional view of the aerosol generator of FIG. 12 taken along line 10-10. [Figure 14] FIG. 14 shows a perspective view of the aerosol generator of FIG. [Figure 15] FIG. 15 shows a top view of an aerosol generator according to a fifth embodiment of the present disclosure. [Figure 16] FIG. 16 shows a cross-sectional view of the aerosol generator of FIG. 15 taken along line 13-13. [Figure 17] FIG. 17 shows an exploded perspective view of the base plate of the aerosol generator of FIG. [Figure 18] FIG. 18 shows a cross-sectional view of an aerosol generating device including the aerosol generator of FIG. [Figure 19] FIG. 19 shows a cross-sectional view of an aerosol generator according to a sixth embodiment of the present disclosure. [Figure 20] FIG. 20 shows an exploded perspective view of the base plate of the aerosol generator of FIG. [Figure 21] FIG. 21 shows a cross-sectional view of an aerosol generating device including the aerosol generator of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0094] 1 and 2 show an aerosol generator 100 according to a first embodiment of the present disclosure. The aerosol generator 100 comprises a surface acoustic wave atomizer 102 and a supply element 104 for supplying a liquid aerosol-forming substrate to the surface acoustic wave atomizer 102.

[0095] The surface acoustic wave atomizer 102 comprises a substrate 106 comprising a sheet of piezoelectric material and a transducer 108 disposed on an active surface 110 of the substrate 106. The transducer 108 comprises a first electrode array 112 and a second electrode array 114 interleaved 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, the transducer 108 generates surface acoustic waves on the active surface 110 of the substrate 106. The curved shapes of the first electrode array 112 and the second electrode array 114 result in surface acoustic waves having concave wavefronts concentrated toward the atomization region 116 on the active surface 110 of the substrate 106.

[0096] The supply element 104 comprises a channel 118 extending through the substrate 106 between an inlet 120 on a passive surface 122 of the substrate 106 and an outlet 124 on an active surface 110 of the substrate 106. The outlet 124 is positioned within the atomization region 116. In use, a liquid aerosol-forming substrate is supplied through the channel 118 to the atomization region 116, where it is atomized by surface acoustic waves generated by the transducer 108.

[0097] 3 , which shows a perspective view of the channel 118, the channel 118 has a cross-sectional area that varies in the direction from the inlet 120 to the outlet 124. In particular, the channel 118 has a funnel shape such that the cross-sectional area of ​​the channel 118 increases in the direction from the inlet 120 to the outlet 124. The smaller cross-sectional area of ​​the channel 118 at the inlet 120 facilitates control of the flow rate of the liquid aerosol-forming substrate into the channel 118. The larger cross-sectional area of ​​the channel 118 at the outlet 124 provides a larger surface area of ​​the liquid aerosol-forming substrate at the atomization region 116, facilitating atomization of the liquid aerosol-forming substrate. The curved transition at the inlet 120 between the active surface 110 and the channel 118 facilitates the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate.

[0098] 4 and 5 show an aerosol generator 200 according to a second embodiment of the present disclosure. The aerosol generator 200 comprises a surface acoustic wave atomizer 202 and a supply element 204 for supplying a liquid aerosol-forming substrate to the surface acoustic wave atomizer 202.

[0099] The surface acoustic wave atomizer 202 comprises a substrate 206 comprising a sheet of piezoelectric material and a transducer 208 disposed on an active surface 210 of the substrate 206. The transducer 208 comprises a first electrode array 212 and a second electrode array 214 interleaved with the first electrode array 212. The first electrode array 212 and the second electrode array 214 are linear and parallel to each other. During use, the transducer 208 generates surface acoustic waves on the active surface 210 of the substrate 206. The linear shapes of the first electrode array 212 and the second electrode array 214 result in surface acoustic waves having linear wavefronts directed toward the atomization region 216 on the active surface 210 of the substrate 206.

[0100] The supply element 204 comprises a channel 218 extending through the substrate 206 between an inlet 220 at a passive surface 222 of the substrate 206 and an outlet 224 at an active surface 210 of the substrate 206. The outlet 224 is positioned within the atomization region 216. In use, a liquid aerosol-forming substrate is supplied through the channel 218 to the atomization region 216, where it is atomized by surface acoustic waves generated by the transducer 208.

[0101] 6 , which shows a perspective view of channel 218, channel 218 has a cross-sectional area that varies in the direction from inlet 220 to outlet 224. In particular, channel 218 has a wedge shape such that the cross-sectional area of ​​channel 218 increases in the direction from inlet 220 to outlet 224. The smaller cross-sectional area of ​​channel 218 at inlet 220 facilitates control of the flow rate of the liquid aerosol-forming substrate into channel 218. The larger cross-sectional area of ​​channel 218 at outlet 224 provides a larger surface area for the liquid aerosol-forming substrate at atomization region 216, facilitating atomization of the liquid aerosol-forming substrate.

[0102] 7 and 8 show an aerosol generator 300 according to a third embodiment of the present disclosure. The aerosol generator 300 comprises a surface acoustic wave atomizer 302 and a supply element 304 for supplying a liquid aerosol-forming substrate to the surface acoustic wave atomizer 302.

[0103] The surface acoustic wave atomizer 302 comprises a substrate 306 comprising a sheet of piezoelectric material and a transducer 308 disposed on an active surface 310 of the substrate 306. The transducer 308 comprises a first electrode array 312 and a second electrode array 314 interleaved with the first electrode array 312. The first electrode array 312 and the second electrode array 314 are linear and parallel to each other. During use, the transducer 308 generates surface acoustic waves on the active surface 310 of the substrate 306. The linear shapes of the first electrode array 312 and the second electrode array 314 result in surface acoustic waves having linear wavefronts directed toward the atomization region 316 on the active surface 310 of the substrate 306.

[0104] The surface acoustic wave atomizer 302 also includes a reflector 330 positioned on the active surface 310 of the substrate 306 such that the atomization region 316 is positioned between the transducer 308 and the reflector 330. The reflector 330 includes an array 332 of reflector electrodes, each of which has a linear shape and is arranged parallel to each other and to the first array 312 and second array 314 of electrodes of the transducer 308. During use, a portion of the surface acoustic waves generated by the transducer 308 may be transmitted completely through the atomization region 316. The reflector 330 functions to reflect any transmitted surface acoustic waves back toward the atomization region 316.

[0105] The supply element 304 comprises a channel 318 extending through the substrate 306 between an inlet 320 at a passive surface 322 of the substrate 306 and an outlet 324 at an active surface 310 of the substrate 306. The outlet 324 is positioned within the atomization region 316. In use, a liquid aerosol-forming substrate is supplied through the channel 318 to the atomization region 316, where it is atomized by surface acoustic waves generated by the transducer 308.

[0106] 9 , which shows a perspective view of the channel 318, the channel 318 has a cross-sectional area that varies in the direction from the inlet 320 to the outlet 324. In particular, the channel 318 has a curved wedge shape such that the cross-sectional area of ​​the channel 318 increases in the direction from the inlet 320 to the outlet 324. The smaller cross-sectional area of ​​the channel 318 at the inlet 320 facilitates control of the flow rate of the liquid aerosol-forming substrate into the channel 318. The larger cross-sectional area of ​​the channel 318 at the outlet 324 provides a larger surface area of ​​the liquid aerosol-forming substrate in the atomization region 316, facilitating atomization of the liquid aerosol-forming substrate. The curved transition at the inlet 320 between the active surface 310 and the channel 318 at the side of the channel 318 closest to the transducer 308 facilitates the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate.

[0107] Figure 10 shows a first variation of the aerosol generator 300 of Figures 7 and 8. In the first variation shown in Figure 10, the channel 318 has a cross-sectional shape that decreases in the direction from the inlet 320 to the outlet 324.

[0108] Figure 11 shows a second variation of the aerosol generator 300 of Figures 7 and 8. In the second variation shown in Figure 11, the channel 318 extends in a direction non-perpendicular to the active surface 310. In particular, the channel 318 has a substantially straight cross-sectional shape and is sloped toward the transducer 308. Advantageously, sloped channel 318 toward the transducer 308 facilitates the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate and also increases the mechanical stability of the substrate 306 at the outlet 324.

[0109] 12, 13, and 14 show an aerosol generator 400 according to a fourth embodiment of the present disclosure. The aerosol generator 400 comprises a surface acoustic wave atomizer 402 and a supply element 404 for supplying a liquid aerosol-forming substrate to the surface acoustic wave atomizer 402.

[0110] The surface acoustic wave atomizer 402 comprises a substrate 406 comprising a sheet of piezoelectric material and a transducer 408. The substrate 406 comprises a plurality of walls 442 that define a recess 440 in the surface of the substrate 406. The transducer 408 is disposed on an active surface 410 of the substrate 406 within the recess 440.

[0111] The transducer 408 comprises a first electrode array 412 and a second electrode array 414 interleaved with the first electrode array 412. The first electrode array 412 and the second electrode array 414 are linear and parallel to each other. During use, the transducer 408 generates surface acoustic waves on the active surface 410 of the substrate 406. The linear shapes of the first electrode array 412 and the second electrode array 414 result in surface acoustic waves having linear wavefronts directed toward the atomization region 416 on the active surface 410 of the substrate 406.

[0112] The supply element 404 comprises a channel 418 extending through the substrate 406 between an inlet 420 at a passive surface 422 of the substrate 406 and an outlet 424 at an active surface 410 of the substrate 406. The outlet 424 is positioned within the recess 440 and the atomization region 416. During use, a liquid aerosol-forming substrate is supplied through the channel 418 to the atomization region 416, where it is atomized by surface acoustic waves generated by the transducer 408.

[0113] 9 , which shows a perspective view of the aerosol generator 400, the channel 418 has a cross-sectional area that varies in the direction from the inlet 420 to the outlet 424. In particular, the channel 418 has a curved wedge shape such that the cross-sectional area of ​​the channel 418 increases in the direction from the inlet 420 to the outlet 424. The smaller cross-sectional area of ​​the channel 418 at the inlet 420 facilitates control of the flow rate of the liquid aerosol-forming substrate into the channel 418. The larger cross-sectional area of ​​the channel 418 at the outlet 424 provides a larger surface area of ​​the liquid aerosol-forming substrate at the atomization region 416, facilitating atomization of the liquid aerosol-forming substrate. The curved transition at the inlet 420 between the active surface 410 and the channel 418 at the side of the channel 418 closest to the transducer 408 facilitates the transfer of energy from the surface acoustic waves to the liquid aerosol-forming substrate.

[0114] The plurality of walls 442 defining the recess 440 includes a pair of angled walls 444 arranged to reflect surface acoustic waves generated by the transducer 408 toward the atomization region 416. The plurality of walls 442 also includes a rear wall 446 arranged to reflect any surface acoustic waves propagating from the transducer 408 in a direction away from the atomization region 416 back toward the atomization region 416. The plurality of walls 442 also includes a front wall 448 that partially defines the inlet 424 and is arranged to reflect any surface acoustic waves transmitted completely through the atomization region 416 back into the atomization region 416. Advantageously, the walls 444, 446, 448 increase or maximize the energy transferred from the surface acoustic waves to the liquid aerosol-forming substrate within the atomization region 416.

[0115] 15 and 16 show an aerosol generator 500 according to a fifth embodiment of the present disclosure. The aerosol generator 500 comprises a surface acoustic wave atomizer 502 and a supply element 504 for supplying a liquid aerosol-forming substrate to the surface acoustic wave atomizer 502.

[0116] The surface acoustic wave atomizer 502 comprises a substrate 506 comprising a sheet of piezoelectric material, a first transducer 508, and a second transducer 509. The first transducer 508 and the second transducer 509 are disposed on an active surface 510 of the substrate 506.

[0117] Each of the first transducer 508 and the second transducer 509 comprises a first electrode array and a second electrode array as described with respect to the transducer 108 of FIG. 1. The first electrode array and the second electrode array of each of the first transducer 508 and the second transducer 509 are curved and parallel to each other. In use, each of the first transducer 508 and the second transducer 509 generates a surface acoustic wave on the active surface 510 of the substrate 506. The curved shape of the first electrode array and the second electrode array of the first transducer 508 results in a surface acoustic wave having a concave wavefront that is concentrated toward the first atomization region 516 on the active surface 510 of the substrate 506. The curved shapes of the first electrode array and the second electrode array of the second transducer 509 result in surface acoustic waves with concave wavefronts concentrated toward the second atomization area 517 on the active surface 510 of the substrate 506.

[0118] The supply element 504 comprises a plurality of interconnected channels extending through the substrate 506 between an inlet 520 at a passive surface 522 of the substrate 506 and a first outlet 524 and a second outlet 525 at an active surface 510 of the substrate 506. The first outlet 524 is positioned within the first atomization region 516, and the second outlet 525 is positioned within the second atomization region 517.

[0119] The plurality of interconnected channels includes an inlet channel 523, a transverse channel 521, a first outlet channel 518, and a second outlet channel 519. The inlet channel 523 extends from the inlet 520. The transverse channel 521 is in fluid communication with the inlet channel 523. The first outlet channel 518 extends between a first end of the transverse channel 521 and a first outlet 524. The second outlet channel 519 extends between a second end of the transverse channel 521 and a second outlet 525. During use, a liquid aerosol-forming substrate is supplied through the plurality of interconnected channels to the first atomization region 516 and the second atomization region 517, where it is atomized by surface acoustic waves generated by the first transducer 508 and the second transducer 509.

[0120] 17 , which shows an exploded perspective view of substrate 506, substrate 506 is formed from multiple layers of substrate material to facilitate the formation of multiple interconnected channels. Specifically, substrate 506 comprises a first layer 550, a second layer 552, and a third layer 554 of substrate material. First layer 550 of substrate material defines first outlet channel 518 and second outlet channel 519. Second layer 552 of substrate material defines transverse channel 521. Third layer 554 of substrate material defines inlet channel 523. First layer 550, second layer 522, and third layer 524 of substrate material are bonded together to form substrate 506.

[0121] 18 shows a cross-sectional view of an aerosol-generation device 600 comprising the aerosol generator 500. The aerosol-generation device 600 also comprises a liquid reservoir 602 containing a liquid aerosol-forming substrate 604, and a flow control element 606 comprising a micropump. The micropump is arranged to deliver the liquid aerosol-forming substrate 604 from the liquid reservoir 602 to the inlet 520 of the aerosol generator 500.

[0122] The aerosol generating device 600 also includes a power supply 608 comprising a rechargeable battery, and a controller 610. The controller 610 is configured to provide a control signal to the flow control element 606 to control the flow rate of the liquid aerosol-forming substrate 604 from the liquid reservoir 602 to the inlet 520 of the aerosol generator 500. The controller 610 is also configured to provide current from the power supply 608 to the aerosol generator 500 to drive the first transducer 508 and the second transducer 509.

[0123] The aerosol generating device 600 also includes a housing 612 within which the aerosol generator 500, the liquid reservoir 602, the flow control element 606, the power supply 608, and the controller 610 are contained. The housing 612 defines an air inlet 614, a mouthpiece 616, and an air outlet 618. During use, a user draws on the mouthpiece 616 to draw air through the housing 612 from the air inlet 614 to the air outlet 618. The aerosol generated by the aerosol generator 500 is entrained in an airflow through the housing 612 for delivery to the user.

[0124] 19 shows a cross-sectional view of an aerosol generator 700 according to a sixth embodiment of the present disclosure. The aerosol generator 700 comprises a surface acoustic wave atomizer 702 and a supply element 704 for supplying a liquid aerosol-forming substrate to the surface acoustic wave atomizer 702.

[0125] The surface acoustic wave atomizer 702 comprises a substrate 706 comprising a sheet of piezoelectric material and a transducer 708 disposed on an active surface 710 of the substrate 706. The transducer 708 is identical to the transducer 108 described with respect to FIG.

[0126] The supply element 704 comprises a plurality of interconnecting channels extending through the substrate 706 between a first inlet 720 and a second inlet 721 at a passive surface 722 of the substrate 706 and an outlet 724 at an active surface 710 of the substrate 706 .

[0127] The plurality of interconnected channels includes a first inlet channel 723, a second inlet channel 727, a transverse channel 721, and an outlet channel 718. The first inlet channel 723 extends from a first inlet 720. The second inlet channel 727 extends from a second inlet 721. The transverse channel 721 is in fluid communication with the first inlet channel 723 and the second inlet channel 727. The outlet channel 718 extends between the transverse channel 721 and the outlet 724. Advantageously, a first liquid aerosol-forming substrate may be supplied to the first inlet 720, and a second liquid aerosol-forming substrate may be supplied to the second inlet 721. Advantageously, the first liquid aerosol-forming substrate and the second liquid aerosol-forming substrate may be mixed in the plurality of interconnected channels during use to form a mixed liquid aerosol-forming substrate. In use, the mixed liquid aerosol-forming substrate is delivered through a plurality of interconnected channels to outlet 724 for atomization by surface acoustic waves generated by transducer 708 .

[0128] As shown in FIG. 20 , which illustrates an exploded perspective view of substrate 706, substrate 706 is formed from multiple layers of substrate material to facilitate the formation of multiple interconnected channels. Specifically, substrate 706 comprises a first layer 750, a second layer 752, and a third layer 754 of substrate material. First layer 750 of substrate material defines outlet channel 718. Second layer 752 of substrate material defines transverse channel 721. Third layer 754 of substrate material defines first inlet channel 723 and second inlet channel 727. First layer 750, second layer 722, and third layer 724 of substrate material are bonded together to form substrate 706.

[0129] 21 shows a cross-sectional view of an aerosol-generating device 800 comprising an aerosol generator 700. The aerosol-generating device 800 also comprises a first liquid storage portion 802 containing a first liquid aerosol-forming substrate 804, a second liquid storage portion 803 containing a second liquid aerosol-forming substrate 805, and first and second flow control elements 806 and 807, each comprising a micropump. The first flow control element 806 is arranged to supply the first liquid aerosol-forming substrate 804 from the first liquid storage portion 802 to a first inlet 720 of the aerosol generator 700. The second flow control element 807 is arranged to supply the second liquid aerosol-forming substrate 805 from the second liquid storage portion 803 to a second inlet 721 of the aerosol generator 700.

[0130] The aerosol generating device 800 also includes a power supply 808 comprising a rechargeable battery, and a controller 810. The controller 810 is configured to provide control signals to the first flow control element 806 and the second flow control element 807 to control the flow rates of the first and second liquid aerosol-forming substrates 804 to the first inlet 720 and the second inlet 721 of the aerosol generator 700. The controller 810 is also configured to provide electrical current from the power supply 808 to the aerosol generator 700 to drive the transducer 708.

[0131] The aerosol generating device 800 also includes a housing 812 within which the aerosol generator 700, first and second liquid storage portions 802, 803, first and second flow control elements 806, 807, a power supply 808, and a controller 810 are contained. The housing 812 defines an air inlet 814, a mouthpiece 816, and an air outlet 818. During use, a user draws on the mouthpiece 816 to draw air through the housing 812 from the air inlet 814 to the air outlet 818. The aerosol generated by the aerosol generator 700 is entrained in an airflow through the housing 812 for delivery to the user.

Claims

1. An aerosol generator for an aerosol generating device, comprising:

1. A surface acoustic wave atomizer, comprising: a substrate having an active surface defining at least one atomization area; a surface acoustic wave atomizer comprising: at least one transducer positioned on the active surface of the substrate for generating surface acoustic waves on the active surface of the substrate; a supply element arranged to supply a liquid aerosol-forming substrate to the at least one atomization region, the supply element comprising a channel extending through the substrate between an inlet for receiving a supply of liquid aerosol-forming substrate and an outlet positioned within the at least one atomization region of the active surface of the substrate, the channel having at least one of a cross-sectional area that varies in a direction from the inlet to the outlet and a portion that extends in a direction non-perpendicular to the active surface.

2. 10. The aerosol generator of claim 1, wherein at least a portion of the channel has a cross-sectional area that increases in the direction from the inlet to the outlet.

3. 3. The aerosol generator of claim 1 or claim 2, wherein at least a portion of the channel has a funnel shape, a cone shape, or a wedge shape.

4. 4. The aerosol generator according to claim 1, wherein at least a portion of the channel is curved.

5. 5. The aerosol generator of claim 1, wherein at least a portion of the channel at the outlet is curved to form a continuous transition between the channel and the active surface of the substrate.

6. 6. The aerosol generator of claim 1, wherein at least a portion of the channel at the outlet extends tangentially to the active surface.

7. 7. The aerosol generator of claim 1, wherein the outlet has a first side and a second side opposite the first side, the first side being positioned between the second side and the at least one transducer, the channel has a first outlet portion on the first side of the outlet and a second outlet portion on the second side of the outlet, the first outlet portion extending tangentially to the active surface and the second outlet portion extending perpendicularly to the active surface.

8. 8. An aerosol generator as described in any one of claims 1 to 7, wherein the substrate defines a recess in the active surface, the recess extending between the at least one transducer and the outlet, the substrate having a wall at least partially defining the recess, the wall extending perpendicular to the active surface and positioned to reflect surface acoustic waves from the at least one transducer towards the outlet.

9. 9. The aerosol generator of claim 1, wherein the channel comprises a plurality of interconnected channels extending through the substrate between the inlet and the outlet.

10. 10. The aerosol generator of claim 9, wherein the inlet comprises a single inlet, the outlet comprises a plurality of outlets, and the plurality of interconnected channels provide fluid communication between the inlet and each of the plurality of outlets.

11. 10. The aerosol generator of claim 9, wherein the outlet comprises a single outlet, the inlet comprises a plurality of inlets, and the plurality of interconnected channels provide fluid communication between the outlet and each of the plurality of inlets.

12. 12. An aerosol generator as described in any one of claims 1 to 11, wherein the substrate is a laminate material comprising multiple layers of substrate material, at least one of the layers of substrate material defining the outlet, at least one of the layers of substrate material defining the inlet, and at least one of the layers of substrate material defining the channel.

13. An aerosol generating device, comprising: The aerosol generator of claim 11; a controller for controlling the at least one transducer; Power supply and a first liquid reservoir for receiving a first liquid aerosol-forming substrate, the first liquid reservoir being in fluid communication with a first inlet of the plurality of inlets; a second liquid storage portion for receiving a second liquid aerosol-forming substrate, the second liquid storage portion being in fluid communication with a second inlet of the plurality of inlets.

14. An aerosol generating device, comprising: An aerosol generator according to any one of claims 1 to 12; a controller for controlling the at least one transducer; Power supply and an aerosol generating device comprising: 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 at least one atomization region.

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