Smoking device and method for aerosol-generation

Abstract

A smoking device for generating aerosols from a liquid aerosol-forming substrate comprises a device housing (10) that includes a liquid storage unit (16) for the liquid aerosol-forming substrate. The device further comprises a spray area (40), a surface acoustic wave sprayer (SAW sprayer, 15) that includes at least one transducer (20) for generating surface acoustic waves and propagating them along the surface of a SAW sprayer (15), at least a second transducer (20), and a supply element (30) arranged to supply the liquid aerosol-forming substrate from the liquid storage unit (16) to the spray area (40) on the SAW sprayer (15). The device further comprises a control system (14) configured to operate the SAW sprayer (15) to generate an aerosol by spraying the liquid aerosol-forming substrate into the spray area (40). A cartridge for such a smoking device and a method for generating an aerosol in a smoking system are also provided.

Description

Technology Field

[0001] The present invention relates to a smoking device, a method for generating an aerosol of a liquid aerosol-forming substrate, a smoking system, and a cartridge for the smoking device. The smoking device and the aerosol generating device are electrically operated devices and systems. Background Technology

[0002] In electric smoking systems, for example, a liquid aerosol-forming substrate is atomized to form an aerosol. Typically, in a nebulizer, a coil of heat wire is wound around a slender wick submerged in the liquid aerosol-forming substrate. Another type of nebulizer uses ultrasonic vibrations rather than heat to atomize the liquid substrate. Here, vibrations are used to push or draw the liquid through a mesh and to atomize the liquid. A problem with most nebulizers using ultrasonic vibrations is that they cannot atomize high-viscosity liquids, such as those typically used in electric smoking systems. Additionally, many nebulizers require high power to achieve the desired atomization rate.

[0003] A smoking device for aerosol generation of a liquid aerosol-forming substrate is required to improve these problems. A smoking device for aerosol generation of a liquid aerosol substrate requiring low power is required to achieve effective atomization.

[0004] According to a first aspect of the present invention, a smoking device for generating an aerosol of a liquid aerosol-forming substrate is provided as described in claim 1. The smoking device comprises a device housing comprising a liquid reservoir having a housing for holding a liquid aerosol-forming substrate. For example, the device housing may include a cavity for receiving a cartridge inside, the cartridge comprising a liquid aerosol-forming substrate. The smoking device further comprises a surface acoustic wave (SAW) atomizer (SAW atomizer) comprising a spray area, at least one input transducer for generating a surface acoustic wave (SAW) and propagating it along the surface of the SAW atomizer having the spray area, and at least one output transducer for converting the surface acoustic wave into an electrical signal representing physical information of the spray area. A supply element is arranged to supply the liquid aerosol-forming substrate from the liquid reservoir to the spray area on the SAW atomizer. The supply element may fluidly connect the liquid reservoir, for example, a cartridge, with the SAW atomizer, particularly the spray area on the SAW atomizer. The control system is configured to operate a SAW atomizer according to an electrical signal to generate an aerosol by spraying a liquid aerosol-forming substrate into a spray area. The control system may include, for example, a power supply and control electronics connected to the SAW atomizer. The control system is configured to provide an RF signal, for example, to at least one transducer. The generated aerosol can then be transported within the device housing to a downstream end of the smoking device and to the user of the smoking device.

[0005] When in use, the user may operate the device by manipulating a switch or inhaling through the device's mouthpiece. Power is supplied to the SAW atomizer to activate at least one input transducer to generate surface acoustic waves (Rayleigh waves) that can propagate along the surface of the SAW atomizer. The energy of these surface acoustic waves is transferred to a liquid aerosol-forming substrate supplied to the spray area. The energy supplied into the liquid causes the formation of aerosol droplets in the liquid aerosol-forming substrate, thereby atomizing the liquid aerosol-forming substrate from the spray area. The surface acoustic waves transmitted into the liquid, which cause the droplet surface to break and form a mist of aerosol droplets, essentially destabilize the liquid droplets on the surface of the SAW atomizer.

[0006] This method of generating aerosols has been proven to provide a reliable and consistent amount of aerosol from a liquid aerosol-forming substrate for a convenient smoking experience. Furthermore, aerosol generation requires less power than when generated by known vibrating elements, such as those utilizing heat.

[0007] As a SAW atomizer, a generally known SAW sensor chip may be used. This chip typically comprises at least an interdigital (or interdigitated) transducer containing (metal) electrodes, for example, printed on a substrate, disposed on a piezoelectric substrate. Due to alternating regions of tensile and compressive strain within the piezoelectric substrate created between the fingers, an AC voltage applied to the individual 'fingers' of the transducer electrodes mechanically deforms the piezoelectric substrate. Since the fingers on the same side of the transducer are in the same level of compressive or tensile state, the gap (known as pitch) between them corresponds to the wavelength of the mechanical wave.

[0008] The waves generated in this way typically have a nanometer-sized amplitude and propagate along the surface of the piezoelectric substrate at a frequency of MHz.

[0009] Preferably, at least one input converter of the SAW atomizer used in the smoking device according to the present invention is an interdigital converter comprising an electrode disposed on a piezoelectric substrate.

[0010] The transducer may include a reflector to support the directionality of the generated surface elastic waves in one direction. This can increase the power efficiency of the system.

[0011] The transducer can be configured to generate parallel waves, for example, by means of a linear electrode array arranged in parallel.

[0012] The transducer may be configured to have a focusing effect on the generated waves. For example, the transducer may be equipped with electrodes having a parallel but curved shape to focus the generated waves onto an area.

[0013] Preferably, the transducer includes a reflector and has a focusing effect.

[0014] The control system of the smoking device is configured to operate the SAW atomizer to generate surface acoustic waves at a predetermined frequency. The predetermined frequency may be about 20 MHz or higher, for example, from about 20 MHz to about 100 MHz, or from about 20 MHz to about 80 MHz. This can provide a desired aerosol output rate and a desired droplet size for a good user experience.

[0015] The control system may include an electrical circuit connected to a SAW sprayer and a power source.

[0016] The electrical circuit may include a microprocessor, which may be a programmable microprocessor. The electrical circuit may include additional electronic components. The electrical circuit may be configured to regulate the power supply to the SAW atomizer. Power may be supplied continuously after the device is activated or intermittently, for example, on a puff-by-puff basis, to the SAW atomizer.

[0017] The SAW sprayer may be of any suitable shape. The SAW sprayer may be substantially circular or elliptical. The SAW sprayer may be substantially triangular or square, or of any regular or irregular shape. Preferably, the SAW sprayer is substantially flat. The SAW sprayer may be curved. The SAW sprayer may be dome-shaped. The SAW sprayer may be a substantially square flat plate. The SAW sprayer may be a substantially circular or elliptical disc.

[0018] The SAW atomizer may be reusable. The SAW atomizer may be disposable. The SAW atomizer may be an individual component or a part of the cartridge described below.

[0019] SAW atomizers are generally small and lightweight. Furthermore, SAW atomizers, which have a size particularly suitable for use in electric smoking devices, use less power than known vibrating elements, such as those that use heat for aerosol production. Additionally, SAW atomizers generally have the ability to generate aerosols with small droplet sizes. These advantages of SAW atomizers improve the smoking device of the present invention and enable the provision of an efficient and economical smoking device.

[0020] A smoking device according to the present invention may further include a heater disposed to heat a liquid aerosol-forming substrate, preferably a liquid aerosol-forming substrate within a spray area. The heater may be disposed to heat at least a portion of a SAW-sprayer and thereby heat the aerosol-forming substrate on the SAW-sprayer. Preferably, the heater is disposed to heat at least the spray area of ​​the SAW-sprayer and thereby heat the aerosol-forming substrate within the spray area.

[0021] The heater can heat the liquid aerosol-forming substrate and reduce the viscosity and surface tension of the liquid. Preferably, by heating the liquid before and during atomization, the heater can increase the atomization rate. Heating the aerosol-forming substrate and reducing the viscosity of the liquid aerosol-forming substrate may also increase the reliability of the device or smoking system.

[0022] The heater can heat the liquid aerosol-forming substrate to a uniform predetermined temperature for atomization. This allows the aerosol-forming substrate to be atomized with a uniform viscosity, and enables the generation of aerosols by the device to occur at a uniform atomization rate. This can improve the user experience.

[0023] The viscosity of the liquid aerosol-forming substrate can significantly affect the spray rate and the droplet size of the aerosol generated by the device or system. Therefore, heating the liquid aerosol-forming substrate to a uniform predetermined temperature before spraying can facilitate the generation of aerosols with a uniform droplet size distribution.

[0024] In addition, heating the liquid aerosol-forming substrate to a temperature higher than the ambient temperature before spraying can reduce the system's sensitivity to changes in ambient temperature and provide a uniform aerosol to the user every time it is used.

[0025] As used herein, the term 'droplet size' is used to mean the aerodynamic droplet size, which is the size of a spherical unit-density droplet falling at the same velocity as the droplet in question. Various methods are used in the art to describe aerosol droplet size. These methods include the mass median diameter (MMD) and the mass median aerodynamic diameter (MMAD). As used herein, the term 'mass median diameter (MMD)' is used to mean the diameter of a droplet such that half of the aerosol mass is contained within small-diameter droplets and the other half within large-diameter droplets. As used herein, the term 'liquid median aerodynamic diameter (MMAD)' is used to mean the diameter of a unit-density sphere having the same aerodynamic properties as a droplet consisting of the median mass of the aerosol.

[0026] The mass median aerodynamic diameter (MMAD) of a droplet generated by the smoking device and system of the present invention may be about 1 μm to about 10 μm, or the MMAD may be about 1 μm to about 5 μm. The MMAD of the droplet may be 3 μm or less. The preferred droplet size of the droplet generated by the smoking device of the present invention may be any of the aforementioned MMADs. The desired droplet size (MMAD) may be 3 μm or less.

[0027] The control system of the smoking device may preferably be configured to heat at least a portion of the SAW atomizer to a predetermined temperature, thereby operating a heater to heat the liquid aerosol forming substrate to a predetermined temperature. The predetermined temperature may be above the ambient temperature. The predetermined temperature may be above room temperature. This can reduce the viscosity as well as the surface tension of the aerosol forming substrate compared to the viscosity of the unheated aerosol forming substrate. This can increase the spraying speed and facilitate the generation of aerosols having a desirable droplet size. This can reduce the sensitivity of the system to the ambient temperature. The predetermined temperature may be below the vaporization temperature of the liquid aerosol forming substrate or lower than its boiling point. The predetermined temperature may be 18°C ​​to 80°C, or 30°C to 60°C, or 35°C to 45°C. The predetermined temperature may be 20°C to 30°C, 30°C to 40°C, 40°C to 50°C, 50°C to 60°C, 60°C to 70°C, or 70°C to 80°C. Preferably, the predetermined temperature of the heated part of the SAW atomizer corresponds to the predetermined temperature of the liquid aerosol-forming substrate within the atomization area.

[0028] As used herein, the term 'ambient temperature' refers to the temperature of the surrounding environment in which an aerosol generating device or system is being used. The ambient temperature generally corresponds to a temperature of about 10°C to 35°C. As used herein, the term 'room temperature' refers to standard ambient temperature and pressure, typically a temperature of about 25°C and an absolute pressure of about 100 kPa (1 atmosphere).

[0029] The control system configured to operate the heater may be integrated with or separate from the control system of the smoking device.

[0030] The control system may include an electrical circuit connected to a heater and a power source. The electrical circuit may be configured to monitor the electrical resistance of the heater and control the power supply to the heater based on the electrical resistance of the heater. The electrical circuit may include a microprocessor, which may be a programmable microprocessor. The electrical circuit may include additional electronic components. The electrical circuit may also be configured to regulate the power supply to the heater. Power may be supplied continuously after the device is activated or intermittently, for example, on a puff-by-puff basis. Power may be supplied to the heater in the form of pulses of current.

[0031] The heater may be positioned on the surface of the SAW atomizer, preferably next to or opposite the atomizing area. For example, the heater may be positioned on the same surface as the atomizing area and the SAW atomizer. This arrangement allows direct physical or close contact between the heater and the liquid aerosol-forming substrate to be heated to be particularly close to the atomizing area. The heater may, for example, surround or partially surround the aerosol-forming substrate within the atomizing area.

[0032] In an arrangement where a heater is positioned on the surface of a SAW atomizer facing the spray area, the supply of the aerosol-forming substrate to the spray area is not altered by the presence of the heater. Additionally, the heater may be positioned at one location within the spray area, but may also be positioned on the opposite side of the substrate of the SAW atomizer. The size of the heater may correspond to the size of the SAW atomizer. The size of the heater may be limited to the size of the spray area. The size of the heater may correspond to at least the size of the spray area. The position of the heater may be displaced in the direction of the supply element. This enables heating of the liquid before it enters the spray area. Preferably, the heat from the heater is transferred through the substrate of the SAW atomizer by thermal conduction.

[0033] As described, the position of the heater can improve heat transfer between the heater and the liquid aerosol forming substrate on the SAW sprayer.

[0034] The heater may be attached to the SAW sprayer or be a separate heater arranged next to or near the SAW sprayer.

[0035] The heater can be integrated with the SAW sprayer. This can reduce the number of component parts of the device and facilitate simple manufacturing.

[0036] Preferably, the heater is in a heat conduction relationship with the SAW sprayer.

[0037] The heater may also be placed on or inside the housing of the liquid storage unit. Subsequently, the liquid aerosol forming material is at an elevated temperature when supplied from the liquid storage unit to the SAW atomizer.

[0038] The heater may be any suitable heater capable of heating the liquid aerosol-forming substrate. The heater may be an electric heater. The heater may be a resistive heater. The heater may include an induction heating means. The heater may be substantially flat so that it can be manufactured simply. As used herein, the term 'substantially flat' means formed in a single plane and not wrapped around a curved shape or other non-planar shape, or otherwise identified as fitting thereto. A flat heater can be easily handled during manufacturing and can provide a rigid structure.

[0039] The heater may include one or more electrically conductive tracks on an electrically insulating substrate. The electrically insulating substrate may comprise any suitable material and may be a material capable of withstanding high temperatures (exceeding 150°C) and rapid temperature changes. An example of a suitable material is a polyimide film such as Kapton®.

[0040] A control system configured to operate a heater or a SAW atomizer or both may include an ambient temperature sensor to detect the ambient temperature. The control system may include a temperature sensor on the SAW atomizer to detect the temperature of the liquid aerosol-forming substrate within the atomization area. One or more temperature sensors may communicate with the control electronics of the aerosol generator so that the control electronics maintain the temperature of the liquid aerosol-forming substrate at a predetermined temperature. One or more temperature sensors may be thermocouples or resistive temperature sensors. A heater may be used to provide information related to temperature. The temperature-dependent resistivity of the heater may be known and may be used to determine the temperature of at least one heater in a manner known to those skilled in the art.

[0041] In the smoking device according to the present invention, a portion of the supply element may be positioned adjacent to the spray area of ​​the SAW atomizer, while another portion of the supply element may be fluidically connected to the liquid reservoir. The portion of the supply element positioned adjacent to the spray area may extend into the spray area. When the smoking device is ready for use, the supply element may allow the transport of a liquid aerosol-forming material from the liquid reservoir to the spray area, for example, within a cartridge. By doing so, another portion of the supply element may be directly connected to the liquid reservoir, for example, inserted into the contents of the liquid reservoir or positioned adjacent to the contents of the liquid reservoir. However, the aerosol-forming material may also be transported from the liquid reservoir, for example, through a liquid passage, and may be fluidly connected to another portion of the supply element further downstream of the liquid transport from the reservoir to the SAW atomizer. Separation of the liquid transport can improve variability and optimization in the means of transporting the liquid from the liquid reservoir to the SAW atomizer. In particular, the supply element for supplying the liquid aerosol-forming substrate to the SAW sprayer can be optimized for liquid supply to the spray area and distribution across the spray area. Meanwhile, the transport of liquid from the liquid storage unit can be optimized.

[0042] The supply element may be a capillary element, for example, a wick or paper strip, a capillary or penetrating element for penetrating a cartridge containing a liquid aerosol-forming substrate, but is not limited thereto.

[0043] Preferably, the feed element is a capillary element having a capillary action on a liquid aerosol-forming substrate. Preferably, the feed element in the form of a capillary element allows the liquid aerosol-forming substrate to be supplied to the spray area of ​​the SAW atomizer. The capillary element is composed of or includes a material that allows the liquid aerosol-forming substrate to be delivered by the capillary effect. The capillary material is a material that actively delivers liquid from one end to the other. The capillary material is advantageously oriented within the device to transport the liquid aerosol-forming substrate to the spray area on the surface of the SAW atomizer. The capillary material may have a fibrous structure or a sponge structure. The capillary material may include a capillary bundle, a plurality of fibers, a plurality of threads, or a micro-bore tube. The capillary material may include a combination of fibers, threads, and micro-bore tubes. Fibers, threads, and micro-bore tubes can generally be aligned to transport the liquid to the SAW atomizer. The capillary material may include a sponge-like material or a foam-like material. The structure of the capillary material can form multiple small bores or tubes through which liquid can be transported by capillary action.

[0044] Capillary materials may include any suitable material or combination of materials. Examples of suitable materials include sponge or foam materials, ceramic-based, paper-based, or graphite-based materials in the form of fibers or calcined powders, foamed metal or plastic materials, fibrous materials composed of, for example, spun or extruded fibers, such as cellulose acetate, polyester, or combined polyolefin, polyethylene, tylene or polypropylene fibers, nylon fibers, or ceramics. Capillary materials may be paper-based. Capillary materials may have any suitable capillary action and porosity to be used with different liquid properties.

[0045] The liquid aerosol forming substrate has physical properties including, but not limited to, viscosity, surface tension, density, thermal conductivity, and boiling point, which allow the liquid to be transported through the capillary material by capillary action. The capillary material can be configured to transport the liquid aerosol forming substrate to the spray area of ​​a SAW nebulizer. The capillary element is in the form of a sheet. Some capillary materials, such as paper-based wick materials, may additionally have the ability to filter contaminants from the liquid, thereby supporting the spraying of the pure liquid aerosol forming substrate.

[0046] The supply element may be a separate element or a part of the SAW sprayer. Preferably, the supply element is a part of the SAW sprayer, for example, integral with the SAW sprayer.

[0047] The supply element may be a wick element known in the art that utilizes the capillary effect to transport liquid. The supply element may also transport liquid to the spray area, for example, using the Venturi effect. The supply element may be, for example, a microchannel integrated within the substrate of a SAW sprayer, or any combination of the supply elements mentioned above.

[0048] A SAW atomizer may include at least one piezoelectric transducer. A SAW atomizer may include at least one interdigital transducer. The piezoelectric transducer may preferably include a single-crystal material, but may also include a polycrystalline material. The piezoelectric transducer may include quartz, ceramic, barium titanate (BaTiO3), or lithium niobate (LiNbO3). The ceramic may include lead zirconate titanate (PZT). The ceramic may include doping materials such as Ni, Bi, La, Nd, or Nb ions. The piezoelectric transducer may have polarity. The piezoelectric transducer may not have polarity. The piezoelectric transducer may include both polarized and non-polarized piezoelectric materials.

[0049] A SAW atomizer may include a single transducer to generate surface acoustic waves. A SAW atomizer may include one or more transducers to generate surface acoustic waves. The transducer that generates surface acoustic waves is called an input transducer. The input transducer receives an electrical signal and generates surface acoustic waves according to the input signal. One or more input transducers can generate surface acoustic waves to interfere with each other, and preferably, positive interference enhances the energy input into the atomization area. Additional input transducers may be used to center the liquid within the atomization area or, generally, to center the liquid in a small area.

[0050] A SAW atomizer includes one or more transducers. At least one of the one or more transducers is used to generate an electrical signal.

[0051] A transducer that generates an electrical signal is called an output transducer. The output transducer converts surface acoustic waves into an output signal. The surface acoustic waves received by the output transducer are generated by at least one input transducer and propagate along the spray area of ​​the SAW atomizer to the output transducer. The output signal contains information regarding physical processes in the spray area, for example, regarding the amount of liquid present in the spray area. Thus, the SAW atomizer is used as a SAW sensor to obtain information regarding the spraying process. This information is used to control the spraying process. Sensor information is used in a control system that controls the operation of the SAW atomizer. Sensor information can also be used, for example, to control a heater. Control of the spraying process can be achieved, for example, by adjusting the power supplied to the SAW atomizer.

[0052] The SAW atomizer includes at least one output converter. The at least one output converter is used to generate an electrical signal representing physical information of the atomization area. The SAW atomizer may include an additional input converter for generating other surface acoustic waves.

[0053] In the case where there are two transducers, preferably, the two transducers are positioned facing each other with a spray area placed between the two transducers. The first transducer among the two transducers is an input transducer. The second transducer among the two transducers is an output transducer.

[0054] In a smoking device according to the present invention, a liquid reservoir, a SAW atomizer, and a supply element may form a portion of a cartridge. A cartridge including or excluding a SAW atomizer and a supply element may be pre-manufactured. The cartridge may be removable, replaceable, reusable, or disposable. The cartridge may be refillable with a liquid aerosol forming substrate. With a refillable liquid reservoir or, in particular, a replaceable cartridge, the smoking device becomes reusable. Preferably, the cartridge is not refillable but replaced after each use.

[0055] The device housing may include a cavity for receiving a cartridge.

[0056] The cartridge may be removablely coupled to an aerosol generating device. The cartridge may be removed from the aerosol generating device when the aerosol forming material is consumed. As used herein, the term "removably coupled" is used to mean that the cartridge and the device can be coupled and uncoupled from each other without significantly damaging said device or cartridge.

[0057] The cartridge can be manufactured at a low cost in a reliable and repeatable manner. The cartridge can have a simple design. The cartridge can have a housing that holds an aerosol-forming substrate.

[0058] The cartridge may include a liquid holding material that holds an aerosol-forming liquid. The cartridge may be a tank system filled with liquid.

[0059] The cartridge housing may be a rigid housing. As used herein, 'rigid housing' refers to a self-supporting housing. The housing may comprise a material impermeable to liquids.

[0060] The cartridge may include a lid. The lid may be detachable before the cartridge is coupled to an aerosol generator. The lid may be penetrable, for example, by a supply element.

[0061] A cartridge containing a feed element and a SAW atomizer allows for an entirely 'new' atomization process whenever the cartridge is replaced. Deposits or residues within the feed element or on the SAW atomizer can be removed upon cartridge replacement. The SAW atomizer containing the feed element is also reusable and, preferably, may be a permanently mounted element of the smoking device. This can reduce waste and material costs.

[0062] According to another aspect of the present invention, a method for generating an aerosol within a smoking system is provided. The method comprises the step of providing a surface acoustic wave atomizer (SAW atomizer) comprising a spray area, at least one input converter, and at least a second output converter. The method further comprises the step of providing a liquid aerosol-forming substrate to the spray area of ​​the SAW atomizer and operating the SAW atomizer to generate a surface acoustic wave through at least one input converter, wherein the surface acoustic wave propagates along the surface of the SAW atomizer to the spray area and into the liquid aerosol-forming substrate within the spray area, thereby spraying the liquid aerosol-forming substrate and generating an aerosol. The method further comprises the step of using at least one output converter to convert the surface acoustic wave into an electrical signal representing physical information of the spray area; the step of outputting the electrical signal through at least one output converter; and the step of using the electrical signal to control the operation of the SAW atomizer. The method may be performed using a smoking device, a smoking system, and a cartridge according to another aspect of the present invention.

[0063] The present method may have all the advantages described in relation to other aspects of the present invention. For example, features of the SAW atomizer, such as the operating mode of the supply element, for example, the placement and configuration of the heater, for example, a predetermined temperature, may be the same as those described in relation to other aspects of the present invention.

[0064] The present method may include the step of fluidically connecting a cartridge containing a liquid storage unit, for example, a liquid aerosol forming material, to the spray area of ​​a SAW atomizer.

[0065] The present method may include the step of providing a radio frequency signal to at least one converter.

[0066] The present method may further include the step of supplying a liquid aerosol-forming material in an amount corresponding to one puff to a SAW atomizer.

[0067] The present method may preferably include the step of heating a liquid aerosol-forming substrate within a spray area to a temperature higher than room temperature before spraying. Heating may be performed so that the liquid to be sprayed has a temperature above 50°C, for example, between 50°C and 80°C.

[0068] The method according to the present invention includes the step of providing at least one output converter to a SAW sprayer.

[0069] The present method includes the step of outputting an electrical signal to at least one output converter. The output signal represents a physical process in the spray area. The output signal is used to control the operation of a SAW sprayer. For example, the output signal can be used as an input signal to a control system to control a SAW sprayer or a heater.

[0070] The step of providing a surface acoustic wave atomizer may include the step of providing a plurality of input transducers, and the step of operating the SAW atomizer is performed by generating surface acoustic waves with the plurality of input transducers, and the surface acoustic waves propagate along the surface of the SAW atomizer into the spray area and into the liquid aerosol forming substrate within the spray area.

[0071] According to another aspect of the present invention, an aerosol generating smoking system is provided, comprising a smoking device as described herein. The system also comprises a liquid aerosol forming substrate. A supply element is fluidly connected to the liquid aerosol forming substrate contained in the housing of the liquid reservoir of the smoking device and to a spray area on a surface acoustic wave (SAW) atomizer.

[0072] The liquid aerosol-forming substrate comprises at least one aerosol-forming agent and a liquid additive. The aerosol-forming agent may be, for example, propylene glycol or glycerol.

[0073] The liquid aerosol-forming substrate may contain water.

[0074] The liquid additive may be any one or a combination of liquid flavorings or liquid stimulating substances. Liquid flavorings may include, for example, tobacco flavorings, tobacco extracts, fruit flavorings, or coffee flavorings. For example, the liquid additive may be a sweet liquid, such as, for example, vanilla, caramel, and cocoa; an herbal liquid; a spicy liquid; or a stimulating liquid containing, for example, caffeine, taurine, nicotine, or other stimulating agents known for use in the food industry.

[0075] According to another aspect of the present invention, a cartridge for a smoking device for generating an aerosol is provided. The cartridge comprises a liquid reservoir having a housing for holding a liquid aerosol-forming material. The cartridge further comprises a surface acoustic wave (SAW) atomizer (SAW atomizer) having a spray area, at least one input transducer for generating surface acoustic waves and propagating them along the surface of the SAW atomizer having the spray area, and at least one output transducer for converting the surface acoustic waves into an electrical signal representing physical information of the spray area. A supply element is provided and arranged to supply the liquid aerosol-forming material from the housing of the liquid reservoir to the spray area on the SAW atomizer.

[0076] The liquid reservoir, SAW atomizer, supply element, or heater may include any features or may be arranged in any configuration as described above with respect to the liquid reservoir, SAW atomizer, supply element, and heater of the aerosol generating device as described herein. The advantages and features of the cartridge have been described in relation to the smoking device and will not be repeated. Brief explanation of the drawing

[0078] The present invention will be further explained merely by example with reference to the attached drawings: FIG. 1 schematically illustrates an aerosol generator having a SAW sprayer including a focusing transducer and a penetrable cartridge; FIG. 2 schematically illustrates an aerosol generator having a SAW sprayer comprising two focusing transducers; FIG. 3 schematically illustrates an aerosol generator having a pointed SAW sprayer including a focusing transducer and a penetrable cartridge; FIG. 4 shows a SAW sprayer having a linear converter; FIG. 5 shows the SAW sprayer of FIG. 4 having a reflector; FIG. 6 shows a SAW atomizer comprising a linear converter having different reflectors and additional heating elements; FIG. 7 shows a SAW sprayer having a focusing transducer; FIGS. 8 and 9 show a plan view and a cross-sectional view (along the midline AA) of a SAW atom having a focusing converter, a heating element, and a capillary element, wherein the output converter is not shown; FIGS. 10 and 11 show a cross-sectional view along the midline of another embodiment of a SAW atomizer having a heating element, wherein the output converter is not shown; FIGS. 12 and 13 show a plan view of a SAW sprayer having two focusing transducers according to the present invention and a cross-sectional view passing through it (along the median line BB); FIGS. 14 and 15 show a plan view of a SAW atomizer having a supply element containing a microchannel and a cross-sectional view passing through it (along the midline CC), wherein the output converter is not shown; FIGS. 16 and 17 show a plan view of a SAW sprayer having a countersunk feed element and a cross-sectional view passing through it (along the centerline DD), wherein the output converter is not shown; Fig. 18 The figure shows the surface treatment of a SAW sprayer, where the output converter is not shown. Specific details for implementing the invention

[0079] Fig. 1The figure shows an electronic aerosol generator comprising a housing (10) and a mouthpiece (11). The housing comprises a cartridge (16) containing an aerosol-forming liquid, a surface acoustic wave (SAW) atomizer chip (15), an electronic device (14) for operating and controlling the SAW atomizer, and a battery (13) for supplying power to the electronic device (14) and the SAW atomizer (15). The SAW atomizer chip (15) is a rectangular chip comprising a focusing interdigital converter (20) that includes a reflector, which will be described in more detail below.

[0080] A cylindrical cartridge (16) is closed at its distal end toward the SAW atomizer chip by a sealing element, for example, a penetrable or perforable foil (160). The sealing element is penetrated by a supply element in the form of a pointed capillary element (30), for example, a needle or a strip of paper. The other distal end of the capillary element (30) reaches a focusing area of ​​a transducer (20) on the chip, which corresponds to a spray area (40) or vaporization area on the chip (15).

[0081] Fig. 2 Figure 2 shows another embodiment of an electronic aerosol generator, wherein the same reference numbers are used for the same or similar elements. In Figure 2, the SAW atomizer (15) includes two focused interdigital converters (20) positioned facing each other. The atomization area (40) is located between the two converters (20).

[0082] Both transducers can be operated to generate surface acoustic waves. By doing so, atomization in the spray area (40) can be improved, or less power may be required to achieve the same vaporization rate. Alternatively, one of the two transducers can be operated to provide a signal indicating an effect or state in the spray area, such as the vaporization rate or the presence or absence of liquid. The signal can be used within an electronic device (14) to control and enable adjustment of the spraying process.

[0083] In the embodiment of FIG. 2, the distal end of the cartridge (16) is closed by a porous material layer (161). The porous material is in contact with a wick (31), for example, a strip or strand of fiber or a strip of paper, and the wick (31) extends from the porous material (161) to a spray area (40) on the chip (15). Due to the arrangement of two transducers (20) having a wave propagation direction substantially perpendicular to the longitudinal axis of the device, the wick (31) is positioned between the two transducers.

[0084] Fig. 3 FIG. 1 shows another embodiment of an electronic aerosol generating device similar to that illustrated in FIG. 1, and the same reference numerals are used for the same or similar elements. In FIG. 3, the SAW atomizer chip (15) includes a pointed tip portion (150) that supports a penetration portion of the penetrable membrane (160) of the cartridge. A capillary (32) is positioned to extend between the interior of the cartridge (16) and the atomizing area (40) of the chip (15). The capillary (32) may be, for example, a microchannel.

[0085] Optional heaters can be placed on each side of the capillary, the top of the capillary, or the back of the chip.

[0086] FIGS. 4 to 17 show different embodiments of the SAW-sprayer chip (15) and examples of the arrangement and embodiment of the converter, capillary element and heating element.

[0087] Fig. 4 In this case, an interdigital converter (21) is disposed on the lateral surface portion of the piezoelectric substrate. The converter (21) includes a series of linear interlacing electrodes (210) arranged in parallel (linear converter). The spray area (40) is indicated by a dotted line and is disposed on the opposite side surface portion of the piezoelectric substrate, close to the converter. Fig. 5 In this case, the same transducer (21) is equipped with a reflector electrode (215). The linear reflector electrode (215) is positioned parallel to the electrode (210) of the transducer (21) and adjacent to the side of the transducer facing the spray area (40). The reflector electrode can reflect surface acoustic waves in the intended direction of propagation (right side of the drawing). The transducer (21) may have 20 electrode pairs and 32 reflector electrodes (215) positioned, for example, on a LiNbO3 substrate. The electrode material may be gold.

[0088] Fig. 6 The linear converter includes a reflector electrode (216) positioned between the converter electrodes (210). A heating element, for example, a resistive heater (50) in the form of a printed circuit path, is positioned on a substrate facing the spray area (40).

[0089] Fig. 7 This is an example of a focusing interdigital converter (20) having a curved and tapering electrode (211) that focuses the generated waves onto a small focusing area (200) on the surface of a substrate. Between the converter electrodes (211), a curved reflector electrode (214) is positioned parallel to the converter electrodes.

[0090] Fig. 8Figure 7 shows a SAW chip (15) having a strip-shaped capillary element (31), e.g. a wick or capillary, placed across the heater (50) along the direction of propagation of the wave generated by the integrated heater (50) on the surface of the chip and substantially the converter (21).

[0091] Fig. 9 is a cross-section of the chip of FIG. 8. The transducer (20) and the heater (50) are placed on the same surface, the top surface, of a piezoelectric substrate (151), for example, a lithium niobate substrate. The wick (31) is partially placed on the heater and attached to the heater to support heating of the liquid carried within the wick (31) into a spray area placed between the transducer (20) and the heater (50) from a cartridge (not shown).

[0092] Fig. 10 and Fig. 11 Figure 10 shows a cross-section of another embodiment of the SAW chip (15). In Figure 10, the heater (50) is positioned on the opposite, rear side of the substrate (151). The heater is positioned to 'extend' into the spray area and 'overlap' with the wick (31), but the substrate (151) is positioned between them. The thickness of the piezoelectric substrate may be reduced to reduce the path that heat must pass through the substrate to reach the liquid within the wick (31) or within the spray area. In Figure 11, the transducer (20) and the wick (31) are positioned on the surface of the piezoelectric layer (152), for example, LiNbO3, ZnO, AlN, or other piezoelectric material suitable for the layer for SAW-spray application. The heater (50) is positioned on the rear side of the layer (152) at the same location as described and illustrated in Figure 10.

[0093] The layer (152) is placed on a substrate made of a support (153), for example, glass, ceramic, silicon, or metal. For manufacturing reasons, a heater may be applied to the substrate (153), and the substrate then has a piezoelectric layer (152).

[0094] Although the heater is shown to be placed on the chip, the heater may also be placed along a capillary material or channel between the chip and a cartridge containing an aerosol-forming liquid, for example.

[0095] Fig. 12 and Fig. 13 In this embodiment, two focusing transducers (20) equipped with reflector electrodes are positioned facing each other on a piezoelectric substrate (151). The two transducers (20) have a common focusing area (200) between the transducers. In the focusing area (200), the substrate (151) is provided with a through hole (155), and an aerosol-forming liquid can be supplied to the uppermost surface of the substrate (151) through this through hole. A capillary element (33) is positioned below the substrate (151) to supply the liquid to the lower part of the through hole (155). Optionally, the through hole (155) can be filled with a capillary material. In this embodiment, the spray area (41) is concentrated on the edge of the through hole (155) on the surface of the substrate (151). The sharp edge supports the formation of a very thin layer of aerosol-forming liquid, which facilitates its vaporization.

[0096] Fig. 14 and Fig. 15 In this case, an aerosol-forming liquid is supplied to the chip through a sheet-shaped capillary element of a wick material (34). The sheet (34) extends over the surface of the substrate (151) and partially lies over a series of parallel microchannels (35) provided on the substrate surface. The microchannels extend into a spray area of ​​a linear transducer (21) also placed on the substrate surface. However, the spray area (41) is concentrated on the edges of the microchannels.

[0097] A similar result in which the spray area (41) is concentrated on the substrate edge (156) is also Fig. 16 and Fig. 17This can be achieved by a countersunk capillary element (36) as illustrated in the figure. A portion of the substrate surface is removed, for example, by etching. On this lower surface portion, a capillary element, such as a strip of paper, is placed coplanar with the edge (156) of the lower portion to enable the liquid to be transported to the edge (156).

[0098] Additionally, the surface treatment of the substrate (151) can support the formation of a thin aerosol-forming liquid layer. The surface treatment can also support the localization of this layer. For example, and Fig. 18 As illustrated in [Image], the spray area (40) (indicated by a dotted line) can be treated to form a hydrophilic portion, while the portion outside the concave spray area can be a hydrophobic portion (158).

[0099] An exemplary power range for operating a SAW chip comprising one or two transducers in an aerosol generating device according to the present invention is 5 watts to 15 watts, preferably less than 20 watts. A typical transducer electrode distance is within the range of about 100 μm (linear transducer), while a reflector distance may be within the range of about 50 μm.

[0100] The size of the rectangular SAW chip containing two converters is approximately 50 mm x 20 mm to 55 mm x 25 mm.

[0101] An exemplary aerosol-forming liquid composition was 40% to 80% propylene glycol, 20% water, and 0% to 40% glycerol. The aerosol-forming liquid was heated to about 65°C. About 5 μL of this liquid was sprayed or vaporized within 20 seconds to achieve a vaporization rate of about 0.2 to 0.3 μL / second or higher.

Claims

Claim 1 A smoking device for generating aerosols from a liquid aerosol-forming substrate, wherein the smoking device comprises: a device housing including a liquid storage unit including a housing for holding a liquid aerosol-forming substrate; a surface acoustic wave atomizer (SAW atomizer) including a spray area, at least one transducer for generating surface acoustic waves and propagating them along the surface of the SAW atomizer including the spray area, and at least a second transducer; a supply element arranged to supply a liquid aerosol-forming substrate from the liquid storage unit to a spray area on the SAW atomizer; and a control system configured to operate the SAW atomizer to spray the liquid aerosol-forming substrate into the spray area to generate an aerosol. Claim 2 A smoking device according to claim 1, wherein at least one converter is an interdigital converter comprising an electrode disposed on a piezoelectric substrate. Claim 3 A smoking device according to claim 1 or 2, further comprising a heater arranged to heat a liquid aerosol-forming substrate. Claim 4 A smoking device according to paragraph 3, wherein the control system is configured to operate the heater to heat the liquid aerosol forming substrate to a predetermined temperature. Claim 5 A smoking device according to claim 3 or 4, wherein the heater is disposed on the surface of the SAW-sprayer next to the spray area or on the surface of the SAW-sprayer opposite the spray area. Claim 6 A smoking device according to any one of claims 1 to 5, wherein a part of the supply element is positioned adjacent to the spray area of ​​the SAW-atomizer, and another part of the supply element can be fluidly connected to the liquid storage unit. Claim 7 A smoking device according to any one of claims 1 to 6, wherein the supply element is a capillary element having capillary action on a liquid aerosol-forming substrate to be supplied to the spray area of ​​the SAW-sprayer. Claim 8 A smoking device according to any one of claims 1 to 7, wherein the at least second converter is for generating an electrical signal representing physical information of the spray area or for generating additional surface elastic waves. Claim 9 A smoking device according to any one of claims 1 to 8, wherein the liquid storage portion, the SAW atomizer, and the supply element form a portion of a cartridge, and the device housing includes a cavity for receiving the cartridge. Claim 10 A method for generating an aerosol within a smoking system, the method comprising the steps of: providing a surface acoustic wave atomizer (SAW atomizer) comprising a spray area and at least one transducer; providing a liquid aerosol-forming substrate to the spray area of ​​the SAW atomizer; operating the SAW atomizer to generate a surface acoustic wave through the at least one transducer, wherein the surface acoustic wave propagates along the surface of the SAW atomizer to the spray area and into the liquid aerosol-forming substrate within the spray area, thereby spraying the liquid aerosol-forming substrate and generating the aerosol. Claim 11 A method according to claim 10, further comprising the step of heating the liquid aerosol-forming substrate within the spray area to a temperature above room temperature. Claim 12 A method according to claim 10 or 11, further comprising the steps of: providing at least a second transducer to the SAW-sprayer; and outputting a signal to the at least one second transducer, wherein the output signal represents a physical process in the spray area; and using the output signal to control the operation of the SAW-sprayer, or generating additional surface acoustic waves to the at least one second transducer, wherein the additional surface acoustic waves propagate along the surface of the SAW-sprayer into the spray area and into a liquid aerosol forming substrate within the spray area. Claim 13 An aerosol generating smoking system comprising a smoking device according to any one of claims 1 to 9 and a liquid aerosol forming substrate, wherein a supply element is fluidly connected to a liquid aerosol forming substrate included in the housing of a liquid storage part of the smoking device and to a spray area on a surface acoustic wave atomizer (SAW atomizer). Claim 14 In claim 13, the above-mentioned liquid aerosol forming substrate comprises at least one aerosol forming agent and a liquid additive, in an aerosol generating system. Claim 15 A cartridge for a smoking device for generating an aerosol, wherein the cartridge comprises: a liquid storage portion including a housing for holding a liquid aerosol-forming material; a surface acoustic wave atomizer (SAW atomizer) including a spray area, at least one transducer for generating a surface acoustic wave and propagating it along the surface of the SAW atomizer including the spray area, and at least a second transducer; and a cartridge comprising a supply element arranged to supply the liquid aerosol-forming material from the housing of the liquid storage portion to the spray area on the SAW atomizer.

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