Aerosol-generating device and system

Abstract

This invention discloses an aerosol generation apparatus. The apparatus includes: a membrane having an aerosol generation region, wherein the aerosol generation region includes a plurality of nozzles, the plurality of nozzles being the only nozzles in the aerosol generation region; and an actuator coupled to the membrane; wherein the actuator is configured to excite the membrane to induce vibration of the membrane at one or more predetermined modal frequencies, so as to aerosolize a liquid aerosol passing through the plurality of nozzles into a matrix aerosol in use; wherein the plurality of nozzles are preferentially positioned close to antinodes of the membrane corresponding to the one or more predetermined modal frequencies at which the membrane is excited. The thickness of the membrane gradually changes from the central region of the membrane toward the periphery of the membrane.

Description

Technical Field

[0001] This disclosure relates to an aerosol generation apparatus and system for aerosolizing a liquid aerosol into a matrix by using a vibrating perforated membrane. Background Technology

[0002] Known vibratory atomizers for aerosolizing liquid aerosol-forming matrix employ a membrane with uniformly distributed nozzles. "Uniformly distributed" means that the nozzles are evenly distributed above the membrane surface, with all nozzles having the same profile and size. The membrane is coupled to an actuator, which induces vibration of the membrane. When the membrane comes into contact with the liquid aerosol-forming matrix, the vibration causes the liquid aerosol-forming matrix to be propelled through the nozzles to form aerosol droplets. However, such known vibratory atomizers exhibit inconsistent aerosol quality above the membrane area.

[0003] An improved method is needed to use vibratory perforated membranes to form matrix aerosols from liquid aerosols. Summary of the Invention

[0004] According to one aspect of the present invention, an aerosol generating apparatus is provided, the aerosol generating apparatus comprising:

[0005] A membrane having an aerosol generation zone, wherein the aerosol generation zone includes a plurality of nozzles, the plurality of nozzles being the only nozzles in the aerosol generation zone; and

[0006] An actuator, the actuator being coupled to the membrane;

[0007] The actuator is configured to excite the membrane to cause vibration of the membrane at one or more predetermined modal frequencies, so as to form a matrix aerosol from the liquid aerosol passing through the plurality of nozzles during use.

[0008] The plurality of nozzles are preferably positioned close to the antinodes of the membrane corresponding to the one or more predetermined modal frequencies of the membrane.

[0009] As used herein, the term "nozzle" refers to an opening, hole, or pore through a membrane that provides a pathway for the movement of a liquid aerosol-forming matrix across the membrane.

[0010] As used in this article, the term "antinode" refers to those locations on the membrane where the displacement amplitude of the membrane is greatest between adjacent nodal lines when the membrane vibrates at its modal frequency.

[0011] As used in this paper, the term "node" refers to those locations on the membrane where the displacement of the membrane is always zero when the membrane vibrates at its modal frequencies. When a given vibrational mode of the membrane is excited at the corresponding modal frequency, the nodes are defined along one or more lines, called "nodal lines".

[0012] As used herein, the term "modal frequency" refers to either the natural or resonant frequency of the membrane. Each vibrational mode of the membrane will have a different frequency and shape, referred to as the modal frequency and modal shape, respectively. The lowest (or first) modal frequency of the membrane is called the fundamental frequency. The modal frequencies of the membrane will be affected by its physical properties and any boundary conditions applied to the membrane. For example, Young's modulus, Poisson's ratio, and the mass density of the membrane, as well as any constraints on the membrane, can each individually affect the modal response of the membrane in terms of the modal frequency and modal shape associated with a given mode.

[0013] As used in this article, the term “predetermined modal frequency” refers to the modal frequency of the membrane to which the actuator is specifically designed to excite.

[0014] In cases where this application relates to a first predetermined modal frequency and a second predetermined frequency, the terms "first" and "second" indicate that the corresponding frequencies relate to different vibration modes, and it is not required that the first predetermined modal frequency is the fundamental frequency of the membrane, and the second predetermined modal frequency is a second overtone or harmonic of the membrane.

[0015] As used herein, the term “preferential positioning” means that more than 50% of a plurality of nozzles are positioned close to the antinodes of the membrane corresponding to one or more predetermined modal frequencies of the membrane.

[0016] As used herein, the term "closer" means that the nozzle is closer to the antinode than the node, where the antinode and node correspond to the membrane being excited at one or more predetermined modal frequencies of the membrane.

[0017] Preferentially positioning multiple nozzles close to antinodes of the membrane corresponding to one or more predetermined modal frequencies excited at the membrane helps maximize the energy and velocity imparted to individual aerosol droplets by the membrane vibrations. Increasing the velocity imparted to individual aerosol droplets has the benefit of increasing the distance these droplets are ejected from the nozzles of the membrane. Preferably positioning the nozzles close to antinodes also provides aerosol droplet formation with increased uniformity above the aerosol generation region compared to aerosol droplet formation produced by a membrane with uniformly distributed nozzles.

[0018] Preferably, multiple nozzles are non-uniformly distributed above the aerosol generation zone.

[0019] Different aerosol droplet formation schemes can be quantified by referring to various parameters, where the values ​​of the parameters provide a measure of the quality of aerosol droplet formation. An example of such a parameter is the Weber number, We. For a membrane with a nozzle arrangement in an aerosol generation region, where the nozzles are circular when viewed in a plan view, and where all nozzles have the same diameter, the membrane vibrates at a given frequency f and contacts a given liquid aerosol forming matrix with the vibrating membrane such that the liquid aerosol forming matrix is ​​aerosolized through the nozzles, the Weber number can be expressed as:

[0020]

[0021] in:

[0022] It is the mass density of the matrix formed by the liquid aerosol;

[0023] v is the velocity at which liquid aerosols form matrix droplets;

[0024] D is the diameter of each nozzle;

[0025] σ is the surface tension of the matrix formed by the liquid aerosol.

[0026] A lower Weber number (We) is associated with the formation of low-quality aerosol droplets. To explain further, the lower the Weber number, the greater the likelihood that a single aerosol droplet will break down into smaller droplets. In extreme cases, the energy imparted to the liquid aerosol formation matrix by membrane vibrations may be so low that some droplets fall back after passing through the nozzles in the membrane to settle on the membrane surface. The phenomenon of a single aerosol droplet breaking down into smaller droplets with the same total volume but smaller surface area is called Rayleigh decomposition or Rayleigh instability. Rayleigh decomposition is highly undesirable and indicates the formation of low-quality aerosol droplets. Conversely, higher Weber numbers are associated with the formation of high-quality aerosol droplets and indicate an increase in the energy and velocity imparted to the aerosol droplets. High-quality aerosol droplet formation will be indicated by the lack of Rayleigh decomposition and the lack of fallback and sedimentation of aerosol droplets on the membrane surface. In summary, droplet size, droplet mass, and droplet velocity are parameters related to the quality of quantitative aerosol droplet formation.

[0027] Preferably, in use, the aerosol generating device generates aerosol droplets comprising droplets with diameters ranging from 0.1 μm to 5 μm.

[0028] For the equation defining the Weber number, the velocity *v* can be expressed as the characteristic velocity of the membrane when excited at a frequency *f*. For a given location on the membrane, this characteristic velocity can be expressed as the displacement of the membrane at that location multiplied by the frequency *f*. Therefore, it can be seen that positioning the nozzle at or as close as possible to an antinode helps to maximize the amount of energy and velocity imparted to the individual liquid aerosol droplets forming the matrix through the membrane. This helps to increase the Weber number of the resulting aerosol droplet formation, where the droplets have a reduced likelihood of Rayleigh decomposition. Positioning multiple nozzles at or as close as possible to an antinode also increases the distance these droplets can eject from the membrane.

[0029] Preferably, the nozzle is circular in shape. Using a circular nozzle is preferred because the circular shape maximizes the area-to-perimeter ratio, thus reducing viscous forces and boundary layer accumulation. However, it has also been found that using an elliptical nozzle results in acceptable performance in the formation of the resulting aerosol droplets.

[0030] Membranes can be formed from polymeric materials, thus offering the advantages of reduced mass and inertia. However, membranes can be formed from any other material, such as metallic materials. A membrane can be a composite of two or more different materials. Factors influencing the selection of membrane materials can include the specific liquid aerosol forming matrix intended for use with and aerosolized by the aerosol generating device. For example, it is highly desirable to select materials for the membrane that will not chemically react or degrade upon contact with the specific liquid aerosol forming matrix. By way of example only, membranes can be formed from any of palladium, stainless steel, copper-nickel alloys, polyimide, polyamide, silicon, or aluminum nitride.

[0031] Different membrane profiles correspond to different modal frequencies and modal shapes. Advantageously, the membrane is circular in profile. It has been found that circularly profiled membranes are advantageous when the aerosol generating device is used in a smoking system in the form of an elongated cylindrical smoking article. Furthermore, the use of circularly profiled membranes also reflects the corresponding circular shape usually associated with common liquid feeding mechanisms such as cores or tubes.

[0032] The liquid aerosol forming matrix may include nicotine. The nicotine comprising the liquid aerosol forming matrix may be a nicotine salt matrix. The liquid aerosol forming matrix may include plant substrate material. The liquid aerosol forming matrix may include tobacco. The liquid aerosol forming matrix may include homogenized tobacco material. The liquid aerosol forming matrix may include tobacco-free material. The liquid aerosol forming matrix may include homogenized plant substrate material.

[0033] A liquid aerosol forming matrix may include at least one aerosol forming agent. An aerosol forming agent is any suitable known compound or mixture of compounds that contributes to the formation of a dense, stable aerosol during use. Suitable aerosol forming agents are well known in the art and include, but are not limited to: polyols, such as triethylene glycol, 1,3-butanediol, and glycerol; esters of polyols, such as mono-, di-, or triacetic acid esters of glycerol; and fatty acid esters of mono-, di-, or polycarboxylic acids, such as dimethyl dodecanoate and dimethyl tetradecanoate. The aerosol forming agent may be a polyol or a mixture thereof, such as triethylene glycol, 1,3-butanediol, and glycerol. A liquid aerosol forming matrix may include other additives and ingredients, such as fragrances.

[0034] Liquid aerosol matrix may include water.

[0035] The liquid aerosol forming matrix may include nicotine and at least one aerosol forming agent. The aerosol forming agent may include glycerol. The aerosol forming agent may include propylene glycol. The aerosol forming agent may include both glycerol and propylene glycol. The liquid aerosol forming matrix may have a nicotine concentration between about 2% and about 10%.

[0036] Conveniently, the actuator may include one or more piezoelectric actuators. A piezoelectric actuator is defined as a piezoelectric actuator. Piezoelectric actuators are preferred because they provide an efficient and lightweight means of inducing vibration of the membrane, exhibiting high energy conversion efficiency from electrical to acoustic / mechanical energy. Furthermore, piezoelectric actuators are provided in a wide variety of materials and shapes. For a piezoelectric actuator, inputting an electrical drive signal to it results in a mechanical output in the form of a vibration signal. The piezoelectric actuator can be coupled to the membrane so that the vibration signal is transmitted to it. Tuning and adjusting the electrical drive signal input to the piezoelectric actuator can result in corresponding changes in the output vibration signal, thereby enabling the actuator to activate different vibration modes of the membrane. Other types of actuators or transducers may be used. For example, magnetostrictive transducers can be used, but they require greater input power than piezoelectric actuators, have a more limited operating frequency range, and require a magnetic field. As another example, electrostrictive transducers can be used, but they require higher drive currents and are more sensitive to temperature changes than piezoelectric actuators, thus affecting performance. Bipolar piezomagnetic transducers can also be used, but they are subject to similar limitations as magnetostrictive transducers. Combinations of different types of actuators or transducers are possible, for example, in a layered or parallel configuration, but this increases the design complexity of the aerosol generation device.

[0037] When all nozzles are positioned precisely at the antinode, optimal energy transfer from the membrane to individual aerosol droplets occurs. However, if most of the multiple nozzles are spatially distributed within a short distance on either side of the antinode, it may result in the formation of aerosol droplets with acceptable quality (e.g., no visible Rayleigh decomposition, or little or no change in droplet size and velocity).

[0038] Preferably, at least 60% of the plurality of nozzles are positioned within a region extending on either side of the antinode, a region in which the membrane displacement amplitude is at least 60% of the membrane displacement amplitude at the antinode for one or more predetermined modal frequencies. All nozzles of the plurality of nozzles may be positioned within this region. In other embodiments, at least 70%, or at least 80%, or at least 90%, or all of the plurality of nozzles are positioned within a region extending on either side of the antinode, a region in which the membrane displacement amplitude is at least 60%, or at least 70%, or at least 80% of the membrane displacement amplitude at the antinode for one or more predetermined modal frequencies. The greater the proportion of the plurality of nozzles positioned close to the antinode, and the closer the proportion of nozzles to the antinode, the greater the quality of aerosol droplet formation produced by the aerosol generating device. As discussed above, the improvement in quality can be indicated by a decreasing trend in Rayleigh decomposition or by a decreasing change in aerosol droplet size and velocity.

[0039] Conveniently, less than 5% of the nozzles are positioned in a region extending on either side of the node, where the membrane displacement amplitude does not exceed 20% of the membrane displacement amplitude at the antinode for one or more predetermined modal frequencies. At the node, zero or minimal energy is delivered to any liquid aerosol forming matrix in contact with the membrane. Therefore, avoiding or minimizing the presence of nozzles at the node helps reduce the likelihood of aerosol droplets falling back and settling onto the membrane surface. Thus, it should be understood that avoiding or minimizing the presence of nozzles at the node helps reduce waste of the liquid aerosol forming matrix during the use of the device. Advantageously, there are no nozzles in a region extending on either side of the node, where the membrane displacement amplitude does not exceed 10% of the membrane displacement amplitude at the antinode for one or more predetermined modal frequencies. Having no nozzles in this region on either side of the node avoids the presence of nozzles in those portions of the membrane, which will impart minimal energy to the liquid aerosol forming matrix and thus reduce the likelihood of Rayleigh decomposition and aerosol droplets falling back and settling onto the membrane surface.

[0040] Conveniently, one or more predetermined modal frequencies are in the frequency range of approximately 50 kHz to approximately 300 kHz. This range has been found to be suitable for aerosol generation. Frequencies that are too low may reduce the volumetric throughput of the liquid through the nozzle of the membrane and negatively impact hydrodynamics and droplet disintegration mechanisms. Frequencies that are too high may pose a risk of acoustic absorption of energy in the liquid and may lead to undesirable heating effects.

[0041] To modify aerosol properties, frequency tuning can be employed using one or more of the following:

[0042] i) Change the frequency of either side of the resonant mode, such as either side of one or more predetermined modal frequencies;

[0043] ii) Changing from one resonant mode to a different resonant mode, such as by changing from one predetermined modal frequency to a different predetermined modal frequency.

[0044] To reduce the complexity of actuator configuration, it may be desirable to limit the number of predetermined modal frequencies that the actuator is configured to excite. Conveniently, the actuator is configured to excite the membrane at a single modal frequency, thereby simplifying the complexity of actuator design. However, preferably, the actuator is configured to excite the membrane at two or more modal frequencies. The ability to excite the membrane at two or more modal frequencies allows the aerosol droplet formation process to be varied. When an aerosol generation device is used to aerosolize a given liquid aerosol forming matrix, the use of different modal frequencies results in correspondingly different aerosol droplet formation; aerosol droplet formation can vary in one or more aspects of velocity, droplet size, and droplet formation density. When the actuator is configured to induce membrane vibration at two or more modal frequencies, the actuator can be configured to automatically switch between different vibration modes. Alternatively or additionally, switching can be achieved through manual intervention by a user interacting with the actuator to switch it between different vibration modes. As a non-limiting example, the actuator may include or be coupled to a dial, button, switch or any equivalent feature that a user may use to engage their finger in order to switch the actuator between different vibration modes.

[0045] One or more predetermined frequencies may include multiple modal frequencies, such as a lowest first modal frequency, a second modal frequency higher than the first modal frequency, a third modal frequency higher than the second modal frequency, and so on. Limiting the number of discrete modal frequencies excited in the membrane by the actuator provides a balance between: i) the ability to generate different aerosol droplet formations during the use of the aerosol generation device, and ii) reducing the complexity and weight of the actuator and the device.

[0046] Preferably, one or more predetermined modal frequencies include a first predetermined modal frequency and a second predetermined modal frequency of the membrane, wherein a plurality of nozzles are preferentially positioned in a first cross region and a second cross region of the aerosol generation region, wherein: for the first cross region, antinodes corresponding to the first predetermined modal frequency of the membrane are close to nodes corresponding to the second predetermined modal frequency of the membrane; and for the second cross region, antinodes corresponding to the second predetermined modal frequency of the membrane are close to nodes corresponding to the first predetermined modal frequency of the membrane. In the context of this preferred embodiment, the term "preferentially positioned" means that more than 50% of the plurality of nozzles are positioned in the first cross region and the second cross region. Furthermore, in the context of this preferred embodiment, the term "close to" means that antinodes corresponding to the first predetermined modal frequency of the membrane are closer to nodes corresponding to the second predetermined modal frequency than antinodes corresponding to the second predetermined modal frequency (and vice versa). As described above, the advantage of preferentially positioning a plurality of nozzles in the first cross region and the second cross region is that excitation of the membrane at the first predetermined modal frequency will result in most aerosol droplets being generated by nozzles in the first cross region. Switching to excitation of the membrane at the second predetermined modal frequency will subsequently result in most aerosol droplets being generated instead by nozzles in the second cross region. It is desirable to increase the proportion of multiple nozzles located in the first and second cross regions.

[0047] Advantageously, all the multiple nozzles in the aerosol generation zone are positioned in the first and second cross regions. In such advantageous examples, exciting the membrane at a first predetermined modal frequency will result in aerosol droplets being generated only by the nozzles in the first cross region, while switching to exciting the membrane at a second predetermined modal frequency will result in aerosol droplets being generated only by the nozzles in the second cross region instead. The features described in this paragraph provide the possibility of generating different aerosol droplet formations from different portions of the membrane at different corresponding modal frequencies.

[0048] For the first cross region, the node corresponding to the second predetermined modal frequency may be located within a first region extending on either side of the antinode corresponding to the first predetermined modal frequency. The first region is a region where, for the first predetermined modal frequency, the membrane displacement amplitude is at least 60%, at least 70%, or at least 80% of the membrane displacement amplitude at the antinode. Alternatively, for the second cross region, the node corresponding to the first predetermined modal frequency may be located within a second region extending on either side of the antinode corresponding to the second predetermined modal frequency. The second region is a region where, for the second predetermined modal frequency, the membrane displacement amplitude is at least 60%, at least 70%, or at least 80% of the membrane displacement amplitude at the antinode. This relative spacing (and vice versa) between the antinodes of the first predetermined modal frequency and the nodes of the second predetermined modal frequency provides the benefit of increasing the uniformity of aerosol droplet formation (and its properties) emanating from the holes in each cross region.

[0049] Conveniently, the nozzle of the first cross region differs from the nozzle of the second cross region in one or both of its shape and size. This difference in shape and size provides additional customization for the formation (and properties) of aerosol droplets generated by the first and second cross regions.

[0050] The modal frequencies and corresponding displacement responses of a membrane will depend on the membrane's physical properties, as well as the loads and boundary constraints acting on it. For example, the membrane's Young's modulus, Poisson's ratio, and mass density can each individually affect the membrane's modal response, for instance, when one or both of the modal frequencies and modal shapes associated with a given vibrational mode are changed. To further explain, assuming all other parameters remain constant, an increase in the membrane's mass density will lead to a decrease in the modal frequency of a given vibrational mode. Providing a membrane with uniform material properties throughout makes the membrane easier to manufacture. However, conveniently, membranes can be formed with non-uniform material properties. Such non-uniform material properties allow for tuning of the modal shape, modal frequencies, and thus the formation of aerosol droplets.

[0051] Preferably, the device is configured to selectively apply and release constraints to the membrane to adjust the membrane's response to one or more predetermined modal frequencies. Changing the boundary constraints acting on the membrane when it is excited at a given frequency will also have the effect of changing the membrane's displacement response at that frequency. This change in the membrane's displacement response at a given frequency can lead to a change in the position of antinodes. Preferably, the device is configured to selectively apply and release constraints along one or more portions of the membrane's periphery. For example, the constraint may be a clamping constraint. The aerosol generating device may also include an electromechanical switch, wherein the operation of the electromechanical switch selectively applies and releases constraints from the membrane. Using an electromechanical switch provides a simple yet effective means of changing the constraints acting on the membrane to adjust the membrane's response to excitation at a given frequency. The electromechanical switch is conveniently used to selectively apply and release constraints near the peripheral edges of the membrane.

[0052] As a non-limiting example, the membrane can be held in place around its periphery using segmented clamps, wherein discrete clamp segments extend around the periphery, and the device is configured to selectively release and apply one or more of the clamp segments. Conveniently, the segmented clamps are configured as part of the actuator of an aerosol generating device.

[0053] Preferably, the actuator is configured to selectively excite different portions of the membrane. As a non-limiting example, the actuator may include multiple actuator segments, each coupled to a different portion of the membrane. Conveniently, each of the multiple actuator segments is a distinct and physically separated element; by way of example only, each distinct and separated element may be provided with its own set of electrodes for actuating it. To provide additional customization of the vibrational modes to be excited in the membrane, each of the actuator segments may be driven independently of the other segments. Independently drivable actuator segments allow the operating phases of one or more segments to vary relative to the other segments, thereby providing the ability to excite vibrational modes in membranes with complex displacement responses. Conveniently, the multiple actuator segments are coupled to the membrane near its periphery.

[0054] The actuator can be configured to apply a modulated drive signal to the membrane to excite it. For example, the spectrum of the modulated signal may contain frequency components that are the natural frequency of the membrane and its higher harmonic frequencies. In one embodiment, the actuator can be configured to excite a vibration mode having a sinusoidal carrier wave of 100 kHz to 200 kHz and an AM sinusoidal modulation of 1 kHz to 20 kHz.

[0055] The modal frequencies and corresponding displacement responses of the membrane will also vary depending on the physical dimensions of the membrane. The membrane thickness can gradually change as it moves from the central region toward the periphery. Preferably, the membrane thickness gradually decreases from the central region toward the periphery. For example, in the case of a circular or elliptical membrane clamped around its periphery, when the membrane is excited at one of the higher harmonic frequencies, the gradual decrease in membrane thickness as it moves away from the center will reduce the displacement change at antinodes across the membrane diameter. Alternatively, the membrane thickness can gradually increase from the central region toward the periphery.

[0056] According to another aspect of the present invention, an aerosol generation system is provided, the aerosol generation system comprising:

[0057] The aerosol generating apparatus as described above;

[0058] The system also includes:

[0059] Liquid feed, operable to supply a liquid aerosol forming matrix to the membrane.

[0060] Conveniently, the aerosol delivery system also includes a replaceable cartridge containing a reservoir for the liquid aerosol forming matrix. The cartridge may additionally include a liquid feed.

[0061] Liquid feed may include tubing for conveying the liquid aerosol forming matrix from a reservoir to the membrane. The liquid feed may also include a feed nozzle through which the liquid aerosol forming matrix can be ejected from a surface adjacent to the membrane. Conveniently, the liquid feed is in the form of tubing extending between the reservoir end and the membrane end, wherein the tubing terminates in the feed nozzle at the membrane end. The liquid feed may include one or more wicking materials. Using wicking materials in the liquid feed allows for a more gradual and controlled pathway from the liquid aerosol forming matrix to the membrane.

[0062] The liquid feed can be static relative to the membrane, thereby simplifying the design of the aerosol generation apparatus. However, preferably, the liquid feed is configured to move laterally along the aerosol generation region of the membrane during membrane arousal by an actuator, in order to supply the liquid aerosol forming matrix to a nozzle located near an antinode corresponding to the membrane being aroused at one or more predetermined modal frequencies. Using such a traversable liquid feed can help reduce the weight of the apparatus by allowing the use of a liquid feed with a smaller surface area coverage than a static liquid feed capable of covering the same surface area of ​​the aerosol generation region.

[0063] Conveniently, the plurality of nozzles includes a first plurality of nozzles and a second plurality of nozzles respectively positioned in a first region and a second region of the aerosol generation zone. The liquid feed may include a first liquid feed and a second liquid feed, wherein the first liquid feed is operable to supply a first liquid aerosol forming matrix to the first region, and the second liquid feed is operable to supply a second liquid to the second region, wherein the first liquid aerosol forming matrix and the second liquid aerosol forming matrix are different from each other. An actuator is operable to excite the membrane at one or more predetermined modal frequencies to aerosolize the first liquid aerosol forming matrix and the second liquid aerosol forming matrix passing through the respective first plurality of nozzles and the second plurality of nozzles during use. This embodiment has the advantage of allowing different liquid aerosol forming matrices to be aerosolized from different regions of the membrane. The first liquid aerosol forming matrix and the second liquid aerosol forming matrix may differ in any aspect of their physical and chemical properties; for example, in one or more aspects of their mass density, viscosity, and surface tension. When excited at a given modal frequency, the first region and the second region of the aerosol generation zone can be selected to have different vibrational characteristics from each other. The selection of the first and second regions may be influenced by the physical properties of the corresponding first and second liquid aerosol forming matrices; for example, such that aerosol droplets from the first liquid aerosol forming matrix in the first region are similar or identical to aerosol droplets from the second liquid aerosol forming matrix in the second region in one or more aspects of droplet velocity, droplet size, and Weber number.

[0064] Conveniently, the membrane is elliptical or circular in planar shape, wherein the first and second regions are arranged concentrically relative to each other. Furthermore, the first and second liquid feeds can be arranged concentrically to supply the corresponding first and second liquid aerosol forming matrices to the corresponding first and second regions. Providing the concentrically arranged first and second liquid feeds with a membrane that is circular or elliptical in planar shape utilizes the fact that the vibration modes of such a circular or elliptical membrane will include displacement modes in which antinodes and nodes are arranged in concentric bands.

[0065] The first and second liquid feeds may alternatively include corresponding first and second linear channels, wherein the first and second linear channels are arranged to supply the first and second liquid aerosol forming matrices to corresponding first and second regions of the aerosol generation zone. Furthermore, the first and second linear channels can be conveniently incorporated into a monolithic structure located above the aerosol generation zone to ensure that the first and second linear channels are positioned adjacent to their corresponding first and second regions. When using membranes with rectangular or square planar shapes, the use of liquid feeds in the form of linear channels as described in this paragraph is particularly suitable because antinodes for different vibration modes of the membrane may also follow linear paths.

[0066] Conveniently, both the first and second plurality of nozzles are preferentially positioned close to antinodes corresponding to a common predetermined modal frequency of the membrane, and the actuator is configured to excite the membrane to induce a vibrational response at the common predetermined modal frequency. The first and second liquid feeds can be configured to simultaneously supply corresponding first and second liquid aerosol forming matrices to corresponding first and second regions. The first and second plurality of nozzles can be configured, in one or both of their size and shape, such that when the membrane is excited at the common predetermined modal frequency, the Weber number of the first liquid aerosol forming matrix passing through the first plurality of nozzles is within 10% of the value of the Weber number of the second liquid aerosol forming matrix passing through the second plurality of nozzles.

[0067] In another non-limiting embodiment, a first plurality of nozzles may be preferentially positioned near antinodes of the membrane corresponding to those excited at a first predetermined modal frequency of the membrane, and a second plurality of nozzles may be preferentially positioned near antinodes of the membrane corresponding to those excited at a second predetermined modal frequency of the membrane, wherein a first liquid aerosol forming matrix feed is configured to supply the first liquid aerosol forming matrix to a first region in synchronization with an actuator that excites the membrane at the first predetermined modal frequency, and a second liquid aerosol forming matrix feed is configured to supply the second liquid aerosol forming matrix to a second region in synchronization with an actuator that excites the membrane at the second predetermined modal frequency. Preferably, the aerosol delivery system is in the form of a consumable device for delivering non-thermally generated aerosols. Advantageously, the aerosol delivery system is a smoking system for non-thermally generated inhalable aerosols. For example, during use of the aerosol delivery system, aerosol droplets generated by the vibration of the membrane of the aerosol generating device form inhalable aerosols. The smoking system may be in the form of an elongated smoking article. The smoking system may include an elongated housing containing an aerosol generating device and a liquid feed, the elongated housing having a distal end and a mouthpiece disposed at the mouthpiece. Conveniently, the elongated housing is cylindrical. The aerosol generating device and the liquid feed are preferably arranged within the elongated housing such that aerosol droplets ejected from the membrane subsequently flow through the mouthpiece to exit the housing. Preferably, the size and shape of the elongated housing are designed to facilitate holding the housing between the thumb and fingers of the user of the smoking system. The smoking system may also include a power supply and electronic control circuitry, the electronic control circuitry being configured to control the operation of an actuator, and the power supply being configured to provide power to the electronic control circuitry and the actuator of the aerosol generating device. The electronic control circuitry and the power supply are preferably contained within the elongated housing. Preferably, the power supply is rechargeable; for example, the power supply may include a lithium-ion battery. When the power supply is rechargeable, the electronic control circuitry may also be configured to control the charging of the power supply. Since no heat is used in the generation of the aerosol, the risk of generating harmful compounds is reduced, as these harmful compounds are generally associated with chemical reactions that occur at higher temperatures. Furthermore, because the membrane of the aerosol generation device responds to changes caused by the actuator, aerosol properties can be modified within the duration of a single suction (typically 2-3 seconds). This is achieved by modifying the electrical drive signal of the actuator during the suction duration, allowing aerosol generation to rapidly adapt to the user's needs. The aerosol delivery system can be described as an "on-demand suction" system.

[0068] In various embodiments of an aerosol delivery system, different liquids can be fed separately to the membrane; for example, a first liquid containing nicotine or other irritants and a second liquid containing flavorings can each be fed separately to the membrane. These different liquids can be fed to different regions of the membrane, each region responding to a different vibrational mode activated by an actuator. Such an aerosol delivery system can result in the ejection of droplets from different regions of the membrane with different chemical compositions. For example, when nicotine is present in the first liquid and flavorings are present in the second liquid, delivering these two different liquids to different regions of the membrane allows nicotine to be present in smaller aerosol droplets and flavorings in larger aerosol droplets, thereby improving user satisfaction. Conversely, presenting nicotine in relatively large aerosol droplets would have the disadvantage of irritating the user's throat. The supply of liquids can be synchronized with the actuation signal of the actuator. For example, when the actuator is activated in one mode, a micropump or valve can be operated to supply one liquid, while when the actuator is activated in another mode, different liquids can be supplied by operating different micropumps or switching the state of the valve. Users can adjust or select their own personalized suction profile, which can take the form of a given electrical drive signal characteristic of the actuator to provide preferred aerosol characteristics.

[0069] While the fumigation system is preferably used for non-thermal aerosol generation, it optionally includes a heater element configured to apply heat to the liquid aerosol-forming matrix before or after matrix aerosolization (i.e., upstream or downstream of the membrane). Preferably, the fumigation system includes a replaceable cartridge located within an elongated housing and housing a reservoir of the liquid aerosol-forming matrix. Optionally, the cartridge further includes a liquid feed.

[0070] The invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0071] Example Ex1: An aerosol generation apparatus comprising: a membrane having an aerosol generation region, wherein the aerosol generation region includes a plurality of nozzles, the plurality of nozzles being only nozzles in the aerosol generation region; and an actuator coupled to the membrane; wherein the actuator is configured to excite the membrane to induce vibration of the membrane at one or more predetermined modal frequencies, so as to aerosolize a liquid aerosol passing through the plurality of nozzles into a matrix aerosol in use; wherein the plurality of nozzles are preferentially positioned close to antinodes of the membrane corresponding to the one or more predetermined modal frequencies at which the membrane is excited.

[0072] Example Ex2: The aerosol generating apparatus according to Example Ex1, wherein the plurality of nozzles are non-uniformly distributed above the aerosol generating area.

[0073] Example Ex3: An aerosol generating apparatus according to any one of Examples Ex1 or Ex2, wherein at least 60%, or at least 70%, or at least 80%, or at least 90% of the plurality of nozzles are located in a region extending on either side of the antinode, the region being a region in which the displacement amplitude of the membrane at the antinode is at least 60%, or at least 70%, or at least 80% for the one or more predetermined modal frequencies.

[0074] Example Ex4: The aerosol generating apparatus according to Example Ex3, wherein all of the plurality of nozzles are positioned within a region extending on either side of the antinode.

[0075] Example Ex5: An aerosol generating apparatus according to any one of Examples Ex1 to Ex3, wherein less than 5% of the plurality of nozzles are positioned in a region extending on either side of the node, the region being a region in which the displacement amplitude of the membrane does not exceed 20% of the displacement amplitude of the membrane at the antinode for the corresponding one or more predetermined modal frequencies.

[0076] Example Ex6: An aerosol generating apparatus according to any one of Examples Ex1 to Ex5, wherein the aerosol generating region extends in a region on either side of the node without a nozzle, the region being a region in which the displacement amplitude of the membrane does not exceed 10% of the displacement amplitude of the membrane at the antinode for the corresponding one or more predetermined modal frequencies.

[0077] Example Ex7: An aerosol generating apparatus according to any one of Examples Ex1 to Ex6, wherein the one or more predetermined frequencies include a plurality of modal frequencies.

[0078] Example Ex8: An aerosol generating apparatus according to any one of Examples Ex1 to Ex7, wherein the one or more predetermined modal frequencies include a first predetermined modal frequency and a second predetermined modal frequency of the membrane, wherein the plurality of nozzles are preferentially positioned in a first cross region and a second cross region of the aerosol generating region, wherein: for the first cross region, an antinode corresponding to the first predetermined modal frequency of the membrane is close to a node corresponding to the second predetermined modal frequency of the membrane; and for the second cross region, an antinode corresponding to the second predetermined modal frequency of the membrane is close to a node corresponding to the first predetermined modal frequency of the membrane.

[0079] Example Ex9: The aerosol generating apparatus according to Example Ex8, wherein all of the plurality of nozzles are positioned in the first intersection region and the second intersection region.

[0080] Example Ex10: An aerosol generating apparatus according to any one of Examples Ex8 or Ex9, wherein: for the first cross region, the node corresponding to the second predetermined modal frequency is located in a first region extending on either side of the antinode corresponding to the first predetermined modal frequency, the first region being a region in which the displacement amplitude of the membrane at the antinode is at least 60%, at least 70%, or at least 80% of the displacement amplitude of the membrane at the antinode for the first predetermined modal frequency; and for the second cross region, the node corresponding to the first predetermined modal frequency is located in a second region extending on either side of the antinode corresponding to the second predetermined modal frequency, the second region being a region in which the displacement amplitude of the membrane at the antinode is at least 60%, at least 70%, or at least 80% of the displacement amplitude of the membrane at the antinode for the second predetermined modal frequency.

[0081] Example Ex11: An aerosol generating apparatus according to any one of Examples Ex1 to Ex10, wherein the apparatus is configured to selectively apply and release constraints to the membrane in order to adjust the response of the membrane to the one or more predetermined modal frequencies.

[0082] Example Ex12: An aerosol generating apparatus according to Example Ex11, wherein the apparatus is configured to selectively apply and release the constraint along one or more portions of the periphery of the membrane.

[0083] Example Ex13: An aerosol generating apparatus according to any one of Examples Ex11 or Ex12, wherein the constraint is a clamping constraint.

[0084] Example Ex14: An aerosol generating apparatus according to any one of Examples Ex11 to Ex13, the apparatus further comprising an electromechanical switch, wherein the constraint is selectively applied and released from the membrane by operation of the electromechanical switch.

[0085] Example Ex15: The aerosol generating apparatus according to Example Ex14, wherein the electromechanical switch is configured to selectively apply and release the constraint near the peripheral edge of the membrane.

[0086] Example Ex16: An aerosol generating apparatus according to any one of Examples Ex1 to Ex15, wherein the actuator is configured to selectively excite different portions of the membrane.

[0087] Example Ex17: The aerosol generating apparatus according to Example Ex16, wherein the actuator includes a plurality of actuator segments, each actuator segment being coupled to a different portion of the membrane.

[0088] Example Ex18: The aerosol generating apparatus according to Example Ex17, wherein the plurality of actuator sections are coupled to the membrane near the periphery of the membrane.

[0089] Example Ex19: An aerosol generating apparatus according to any one of Examples Ex1 to Ex18, wherein the actuator is configured to apply a modulated drive signal to the membrane to excite the membrane.

[0090] Example Ex20: An aerosol generating apparatus according to any one of Examples Ex1 to Ex19, wherein the thickness of the membrane gradually decreases from the central region of the membrane toward the periphery of the membrane.

[0091] Example Ex21: An aerosol delivery system comprising: an aerosol generating apparatus according to any one of Examples Ex1 to Ex20; the system further comprising: a liquid feed, the liquid feed being operable to supply a liquid aerosol forming matrix to the membrane.

[0092] Example Ex22: According to the aerosol delivery system of Example Ex21, the liquid feed is configured to move laterally along the aerosol generation region of the membrane during excitation of the membrane by the actuator, so as to supply the liquid aerosol forming matrix to a nozzle near an antinode of the membrane corresponding to the one or more predetermined modal frequencies.

[0093] Example Ex23: An aerosol delivery system according to any one of Examples Ex21 or Ex22, wherein the plurality of nozzles includes a first plurality of nozzles and a second plurality of nozzles respectively positioned in a first region and a second region of the aerosol generation zone; the liquid feed includes a first liquid feed and a second liquid feed, wherein the first liquid feed is operable to supply a first liquid aerosol forming matrix to the first region, and the second liquid feed is operable to supply a second liquid to the second region, wherein the first liquid aerosol forming matrix and the second liquid aerosol forming matrix are different from each other; the actuator is operable to excite the membrane at one or more predetermined modal frequencies so as to aerosolize the first liquid aerosol forming matrix and the second liquid aerosol forming matrix passing through the respective first plurality of nozzles and second plurality of nozzles during use.

[0094] Example Ex24: According to the aerosol delivery system of Example Ex23, wherein the membrane is elliptical or circular, the first region and the second region are arranged concentrically relative to each other, and the first liquid feed and the second liquid feed are arranged concentrically relative to each other, so as to supply the corresponding first liquid aerosol forming matrix and the second liquid aerosol forming matrix to the corresponding first region and the second region.

[0095] Example Ex25: An aerosol delivery system according to any one of Examples Ex23 or 24, wherein the first plurality of nozzles and the second plurality of nozzles are preferentially positioned close to antinodes corresponding to a common predetermined modal frequency of the stacked films, and the actuator is configured to excite the films to cause vibrations of the films at the common predetermined modal frequency.

[0096] Example Ex26: According to the aerosol delivery system of Example Ex25, the first liquid feed and the second liquid feed are configured to simultaneously supply the corresponding first liquid aerosol forming matrix and the second liquid aerosol forming matrix to the corresponding first region and the second region.

[0097] Example Ex27: An aerosol delivery system according to any one of Examples Ex25 or Ex26, wherein the first plurality of holes and the second plurality of holes are configured in one or both of their size and shape such that when the membrane is excited at the common predetermined modal frequency, the Weber number of the first liquid aerosol forming matrix passing through the first plurality of holes is within 10% of the value of the Weber number of the second liquid aerosol forming matrix passing through the second plurality of holes.

[0098] Example Ex28: An aerosol delivery system according to any one of Examples Ex23 or Ex24, wherein the first plurality of holes are preferentially positioned near the antinodes of the membrane corresponding to a first predetermined modal frequency of the membrane, and the second plurality of holes are preferentially positioned near the antinodes of the membrane corresponding to a second predetermined modal frequency of the membrane, wherein the first liquid feed is configured to supply the first liquid aerosol forming matrix synchronously with the actuator that excites the membrane at the first predetermined modal frequency, and the second liquid feed is configured to supply the second liquid aerosol forming matrix synchronously with the actuator that excites the membrane at the second predetermined modal frequency.

[0099] Example Ex29: An aerosol delivery system according to any one of Examples Ex21 to Ex28, wherein the aerosol delivery system is a smoking system for generating an inhalable aerosol.

[0100] Example Ex30: An aerosol delivery system according to Example Ex29, wherein the aerosol delivery system includes an elongated housing containing the aerosol generating device and the liquid feed, the elongated housing having a distal end and an inlet end, wherein a mouthpiece is disposed at the inlet end.

[0101] Example Ex31: The aerosol delivery system according to Example Ex30 further includes a power supply and an electronic control circuit, the electronic control circuit being configured to control the operation of the actuator, and the power supply being configured to provide power to the electronic control circuit and the actuator, wherein the electronic control circuit and the power supply are contained within the elongated housing. Attached Figure Description

[0102] Several examples will now be described further with reference to the accompanying drawings, in which:

[0103] Figure 1 A schematic diagram of an aerosol delivery system is shown, which takes the form of a smoking article for generating inhalable aerosols.

[0104] Figure 2 A perspective view of an aerosol generating apparatus according to one embodiment is shown.

[0105] Figure 3 It shows Figure 2 A plan view of the membrane of the aerosol generation device.

[0106] Figure 4 A graph showing the displacement of a circular membrane clamped around its periphery in response to activation of vibration mode (0,3) is presented as a function of radial distance. The graph also includes an indication of the position of the nozzles within the membrane.

[0107] Figure 5a A plan view of a circular membrane clamped around its periphery and covered with a contour line is shown, which indicates the displacement of different portions of the membrane in response to the activation of vibrational modes (0,2) within the membrane.

[0108] Figure 5b A plan view of a circular membrane clamped around its periphery and covered with a contour line is shown, which indicates the displacement of different portions of the membrane in response to the activation of vibrational modes (1,2) within the membrane.

[0109] Figure 5c A plan view of a circular membrane clamped around the periphery and covered with a contour line is shown, which indicates the displacement of different portions of the membrane in response to the activation of vibrational modes (3,1) within the membrane.

[0110] Figure 6aA plan view of a square membrane with its periphery simply supported and covered by a contour line is shown, which indicates the displacement of different portions of the membrane in response to the activation of vibrational modes (1, 2) within the membrane.

[0111] Figure 6b A plan view of a square membrane with its periphery simply supported and covered by a contour line is shown, which indicates the displacement of different parts of the membrane in response to the activation of vibrational modes (3,3) in the membrane.

[0112] Figure 7 A graph showing the displacement of a circular membrane clamped around its periphery as a function of radial distance in response to two separate vibrational modes (0,3) and (4,1) activated within the membrane is presented. The graph also includes an indication of the position of the nozzles within the membrane.

[0113] Figure 8a and Figure 8b A side front view of an embodiment of an aerosol generation device is shown, which is configured to selectively apply and release constraints to a membrane. Figure 8a The constraint applied to the membrane is shown, while Figure 8b The constraint released from the membrane is shown.

[0114] Figure 9 A side front view of an embodiment of an aerosol generating apparatus in which the thickness of the membrane gradually decreases as it travels from the central region toward the periphery of the membrane is shown.

[0115] Figure 10 A side front view of an embodiment of an aerosol generating apparatus in which the membrane gradually increases in thickness as it travels from the central region toward the periphery of the membrane is shown.

[0116] Figure 11 A perspective view of a first embodiment of the liquid feeding assembly is shown.

[0117] Figure 12 A perspective view of a second embodiment of the liquid feeding assembly is shown.

[0118] Figure 13 A perspective view of a third embodiment of the liquid feeding assembly is shown. Detailed Implementation

[0119] Figure 1 This is a schematic diagram of an aerosol delivery system 100. For Figure 1The embodiment shown, aerosol delivery system 100, is a smoking system for generating an inhalable aerosol 101. System 100 has an elongated housing 102. The elongated housing 102 includes a power source 103, an electronic control circuit 104, a cartridge 105, a liquid feed assembly 106, and an aerosol generating device 107. The power source 103 is coupled to the electronic control circuit 104 and the aerosol generating device 107 to provide them with power. The electronic control circuit 104 is configured to control the operation of the aerosol generating device 107. In an alternative embodiment where the power source 103 is a rechargeable battery, the electronic control circuit 104 is also configured to control the charging of the rechargeable battery. The elongated housing 102 has a distal end 108 and a mouthpiece 109. A mouthpiece 110 is disposed at the mouthpiece 109 of the housing 102. The cartridge 105 contains a reservoir of a liquid forming matrix (not shown). Figure 1 Not shown, but the cylinder 105 is replaceable, wherein the elongated housing 102 is adapted to allow the cylinder to be removed and replaced. Suitable for use with Figure 1 An embodiment of the exemplary aerosol generating apparatus 107 used in conjunction with the aerosol delivery system 100 shown is described in subsequent paragraphs.

[0120] Figure 2 An embodiment of an aerosol generation apparatus 107 is shown. Apparatus 107 includes a membrane 20 and an actuator 40 coupled to the membrane. For Figure 2 In the embodiment shown, the membrane 20 has a circular shape when viewed in a plan view. The actuator 40 is segmented around its periphery, having four discrete segments 41, 42, 43, and 44. Each segment 41, 42, 43, and 44 has an upper and lower half acting on the corresponding upper and lower surfaces of the corresponding segment of the membrane 20. Each actuator segment 41, 42, 43, and 44 thus serves to constrain the corresponding segment of the membrane 20. Each actuator segment 41, 42, 43, and 44 is designed to be driven independently of the other segments. During operation of the actuator 40, segments 41, 42, 43, and 44 can be driven such that they are in phase with each other or in any desired phase relationship. In an alternative embodiment not shown in the figure, the actuator 40 may be continuous and non-segmented.

[0121] Figure 3 A plan view of the membrane 20 of the aerosol generating device 107 is shown, i.e., when in Figure 2 When viewed in the direction of arrow A. When viewed in a plan view, membrane 20 is circular. For convenience, Figure 3 The actuator 40 is not included. The membrane 20 has an aerosol generation region 21 (whose periphery is...) Figure 3 (Indicated by dashed lines). The aerosol generation zone 21 is provided with multiple nozzles 22. The nozzles 22 are in the form of holes extending through the thickness of the membrane 20. For Figure 3In the embodiment shown, multiple nozzles 22 are positioned only in two annular regions 23, 24. An annular gap 25 exists between the periphery 26 of the membrane 20 and the periphery of the aerosol generation region 21. The annular gap 25 provides space for sections of the actuator 40 (see example...) Figure 2 It can be connected to membrane 20.

[0122] Actuator 40 is configured to excite membrane 20 to induce vibration of the membrane at one or more predetermined modal frequencies. In various embodiments, actuator 40 may be configured to excite membrane 20 to induce vibration of the membrane at multiple discrete modal frequencies. However, for ease of understanding, the displacement of membrane 20 of actuator 40 in response to a single vibration mode of the excited membrane will be discussed first, see [reference to...]. Figure 4 Each vibration mode of membrane 20 will have a corresponding modal frequency.

[0123] Figure 4 The diagram shows the displacement of the circular membrane 20 relative to the radial distance r from the center 27 of the membrane 20 for the membrane vibration mode (0,3) (see [link]). Figure 3 The entire periphery 26 of the membrane is clamped by the actuator 40. Figure 4 The radial distance r in the figure represents a portion of the radius R of the aerosol generation region 21. For mode (0,3), the number 0 indicates that no circumferential vibration mode is activated in the membrane 20, while the number 3 indicates that the third harmonic vibration mode is activated in the radial direction (relative to the center 27 of the membrane).

[0124] like Figure 4 As shown, when mode (0,3) is activated in membrane 20, antinodes exist in three regions of the membrane. For mode (0,3), Figure 4 The displacement shown is an annular region around the center 27 of the membrane 20, with three defined antinode regions 201, 202, and 203 corresponding to the antinode positions. The amplitude of the antinode displacement is at its maximum at the center 27 of the membrane 20 (i.e., in antinode region 201) and gradually decreases with increasing radial distance from the center of the membrane toward the periphery 26 (i.e., see antinode regions 202 and 203). The decrease in displacement amplitude at the antinodes with increasing radial distance r is due to the periphery 26 of the membrane 20 being clamped by the actuator 40 (see...). Figure 2 ). Figure 4 Includes a gray band showing the width of annular regions 23, 24 in which multiple nozzles 22 are disposed. Annular regions 23, 24 surround (i.e., approach) the corresponding antinodes (see...). Figure 4 The antinodes (202, 203) are located in the waveform. The wavelength λ of the waveform associated with this vibration mode (0,3) is... Figure 4 As shown in the image.

[0125] When the liquid aerosol forming matrix is ​​supplied to the membrane 20 in mode (0,3) when the actuator 40 activates the membrane, aerosol droplets will be generated by nozzles 22 positioned in annular regions 23, 24. Since these annular regions 23, 24 and thus the plurality of nozzles 22 are positioned about the antinodes of the vibrational mode (0,3) (i.e., antinode regions 202, 203), the energy and velocity imparted to the aerosol droplets by the membrane 20 will be maximized. This arrangement of nozzles 22 positioned about the antinodes 202, 203 will also increase the Weber number and the distance the membrane 20 can eject aerosol droplets from the membrane. Conversely or additionally, if the actuator 40 is configured to excite different vibrational modes in the membrane, the plurality of nozzles 22 will be preferentially positioned close to the antinodes corresponding to the different vibrational modes.

[0126] Figures 5a to 5c and Figures 6a to 6b The displacement response of different membrane geometries to different vibration modes is shown.

[0127] Figures 5a to 5c A plan view of the circular membrane 20 clamped around the periphery 26 of the membrane is shown for different vibration modes. Each vibration mode will have its own corresponding modal frequency. For Figures 5a to 5c Each of these has a scaled outline overlaid on membrane 20, showing the displacement response of different portions of the membrane to a specific vibration mode.

[0128] Figure 5a The displacement of the clamped circular membrane 20 for vibration mode (0,2) is shown. For mode (0,2), the number 0 indicates that no circumferential vibration mode is activated in the membrane 20, while the number 2 indicates that a second harmonic vibration mode is activated in the radial direction (relative to the center 27 of the membrane). The displacement response of the membrane 20 to this vibration mode has two defined antinode regions along a line extending radially outward from the center 27 of the membrane.

[0129] Figure 5b The displacement of the clamped circular membrane 20 for vibration modes (1,2) is shown. For modes (1,2), number 1 indicates that the fundamental circumferential vibration mode is activated in the membrane 20, while number 2 indicates that the second harmonic vibration mode is activated in the radial direction (relative to the center 27 of the membrane). The displacement response of the membrane 20 for this vibration mode has a single antinode region in the circumferential direction for each half of the membrane, and two antinode regions along a line extending radially outward from the center 27 of the membrane.

[0130] Figure 5cThe displacement response of the clamped circular membrane 20 for vibration mode (3,1) is shown. For mode (3,1), the number 3 indicates that the third harmonic circumferential vibration mode is activated in the membrane 20, while the number 1 indicates that the fundamental vibration mode in the radial direction (relative to the center 27 of the membrane) is activated. The displacement response of the membrane 11 for this vibration mode has three antinode regions in the circumferential direction for each half of the membrane, and one antinode region along a line extending radially outward from the center 27 of the membrane.

[0131] Figure 6a and Figure 6b A plan view of a square membrane 20' simply supported around its perimeter 26' for different vibration modes is shown. Each vibration mode will have its own corresponding modal frequency. For Figure 6a and 6b Each of the figures shown has a scaled outline overlaid on the membrane 20, illustrating the displacement response of different portions of the membrane to a specific vibration mode.

[0132] Figure 6a The displacement of a simply supported square diaphragm 20' for vibration modes (1,2) is shown. For modes (1,2), numeral 1 indicates that the fundamental vibration mode in the y-direction is activated in diaphragm 20', while numeral 2 indicates that the second harmonic vibration mode in the x-direction is activated. The displacement response of diaphragm 20' to this vibration mode has a single antinode region in the y-direction and two antinode regions in the x-direction.

[0133] Figure 6b The displacement (3,3) of a simply supported rectangular membrane 20' for a vibration mode is shown. For mode (3,3), the number 3 indicates that the second harmonic vibration mode in both the x and y directions is activated in membrane 20'. The displacement response of membrane 20' for this vibration mode has three antinode regions in each of the x and y directions.

[0134] If actuator 40 is configured to activate Figures 5a to 5c Circular clamping film 20 or Figure 6a and Figure 6b For any vibration mode shown by a simple square support membrane 20', the displacement response profile provides an indication of the location where peak displacement amplitudes (i.e., crests or troughs) are likely to occur within the membrane. Such a profile can help preferentially position multiple nozzles 22 within the membrane 20 such that they are close to those regions of the membrane experiencing the highest displacement amplitudes (i.e., antinodes). As previously mentioned, this preferential positioning of the nozzles near antinodes helps to maximize the energy and velocity imparted to the aerosol droplets during use of the aerosol generation device 107.

[0135] In an alternative embodiment of the aerosol generation device, the actuator 40 is configured to excite the membrane 20 of the aerosol generation device 107 at two discrete predetermined modal frequencies. Each discrete modal frequency is associated with a corresponding vibration mode. For illustration, Figure 7 The vibration response of the clamped circular membrane 20 is shown for two different vibration modes of the membrane as the radial distance r from the membrane center 27 increases. The two vibration modes are modes (0,3) and (4,1), respectively... Figure 7 The solid and dashed lines represent the modes. For mode (0,3), the number 0 indicates that no circumferential vibration mode is activated in membrane 20, while the number 3 indicates that the third harmonic vibration mode is activated in the radial direction (relative to the center 27 of the membrane). For mode (4,1), the number 4 indicates that the fourth harmonic circumferential vibration mode is activated in membrane 20, while the number 1 indicates that the fundamental vibration mode is activated in the radial direction (relative to the center 27 of the membrane). In this alternative embodiment, a plurality of nozzles 22 are positioned in two discrete regions 231, 241 of the aerosol generation zone 21. The first region 231 of these regions defines a circle positioned at the center of membrane 20, while the second region 241 of these regions takes the form of an annular band. The first region 231 is a first cross region in which the antinodes corresponding to vibration mode (0,3) are positioned close to the node corresponding to vibration mode (4,1). The second region 241 is a second cross region in which the antinodes corresponding to vibration mode (4,1) are positioned close to the node corresponding to vibration mode (0,3). When actuator 40 is in excitation mode (0,3) and the liquid aerosol forming matrix is ​​fed to membrane 20, aerosol droplets are ejected primarily from nozzle 22 in the first cross region 231. However, once actuator 40 switches to excitation mode (4,1), aerosol droplets are instead ejected primarily from nozzle 22 in the second cross region 241.

[0136] Figure 8a and Figure 8b A schematic diagram is shown of an embodiment in which the aerosol generating device 107 is configured to selectively apply and release constraints to the membrane 20. For convenience, Figure 8a or Figure 8b The locations of the plurality of nozzles 22 in the membrane 20 used in this embodiment are not shown. Figure 8a As shown, the two opposite edges of membrane 20 are clamped. A clamp 41 is disposed on the left edge of membrane 20. Clamp 41 is fixed, meaning that clamp 41 continues to clamp the left edge of membrane 20 during operation of the actuator 40 of aerosol generating device 107. A releasable clamp 42 is disposed on the right edge of membrane 20. The releasable clamp 42 is connected to electromechanical switch 43. Figure 8a and Figure 8bAs shown (see arrow B), the electromechanical switch 43 is operable to move the upper half 42a of the releasable clamp 42 relative to the lower half 42b of the clamp, selectively applying and releasing the upper half 42a from the membrane 20, thereby applying and releasing a clamping force on the right edge of the membrane. Releasing and reapplying the clamping force to the edge of the membrane 20 when the membrane is excited by the actuator 40 at a given predetermined modal frequency has the effect of altering the membrane's displacement response to that modal frequency. By preferentially positioning the plurality of nozzles 22 near antinodes corresponding to the displacements of the membrane 20 in each of the different constraint states of the membrane, the altered displacement response of the membrane 20 in response to changes in the constraints applied to the membrane can be utilized.

[0137] Figure 9 and Figure 10 Two different embodiments of the aerosol generating apparatus 107 are shown, wherein the thickness of the membrane 20 gradually changes as it is moved laterally from the central region of the membrane toward the periphery. The nozzle 22 is in... Figure 9 and Figure 10 Both schematically show that the actuator 40 is connected to the upper and lower surfaces of the membrane in the peripheral region of the membrane. Figure 9 An example is shown in which the thickness of the membrane 20 gradually decreases as it moves from the center of the membrane toward the periphery. Figure 10 The opposite case is illustrated, where the thickness of membrane 20 gradually increases as it moves from the center toward the periphery of the membrane. The thickness of membrane 20 is shown in terms of a radial position r relative to the center of the membrane, where the thickness is represented by the symbol t. r express.

[0138] The liquid aerosol forming matrix can be fed to the membrane 20 of the aerosol generating device 107 in various ways. Figure 11 , Figure 12 and Figure 13 An example of a liquid feed assembly 106, 106', 106" for supplying one or more liquid aerosol forming matrices to the membrane 20 of the aerosol generating apparatus 107 is shown. For convenience, actuator 40 is... Figures 11 to 13 None of them are shown in the text.

[0139] Figure 11 A liquid feed assembly 106 operable to supply a liquid aerosol forming matrix to membrane 20 is shown. The liquid feed assembly 106 has a movable stage 1061. A flexible tube 1062 extends between a reservoir of the liquid aerosol forming matrix (not shown) and a feed nozzle 1063. Arrow L indicates the pathway of the liquid aerosol forming matrix from the reservoir through the flexible tube 1062. Although... Figure 11Not shown, but an electric motor is connected to the movable stage 1061. Operation of the motor causes the movable stage 1061 to move laterally along path P along the aerosol generation region 21 of the membrane 20. During excitation of the membrane 20 by the actuator 40, the movable stage 1061 moves laterally above the membrane to supply a liquid aerosol forming matrix through a supply nozzle 1063 near the antinodes corresponding to a predetermined modal frequency and the nozzle 22. Figure 11 The liquid feed assembly 106 shown can be applied to membranes 20 of any shape.

[0140] Figure 12 An alternative liquid feed assembly 106' is shown. The liquid feed assembly 106' is shown together with the circular membrane 20. The liquid feed assembly 106' has three concentrically arranged tubes 1064, 1065, and 1066. The innermost radial tube 1064 defines a first concentric liquid aerosol forming matrix feed channel for feeding a first liquid aerosol forming matrix into the membrane 20. An annular gap between the innermost radial tube 1064 and the intermediate tube 1065 defines a second concentric liquid aerosol forming matrix feed channel for feeding a second liquid aerosol forming matrix into the membrane 20. An annular gap between the intermediate tube 1065 and the outermost radial tube 1066 defines a third concentric liquid aerosol forming matrix feed channel for feeding a third liquid aerosol forming matrix into the membrane 20. Each of the concentrically arranged feed channels feeds or fills a corresponding liquid aerosol forming matrix from a reservoir (not shown). The concentrically arranged first, second, and third liquid aerosol forming matrix feed channels supply their respective liquid aerosol forming matrices to corresponding annular regions of the membrane 20. In an alternative embodiment (not shown), wicking material may be positioned in each of the concentrically arranged first, second, and third liquid aerosol forming matrix feed channels, wherein the wicking material for each concentric feed channel is used to wet the corresponding liquid aerosol forming matrix of that channel. In another alternative embodiment, the liquid feed assembly 106' may also be used in conjunction with an elliptical membrane.

[0141] Figure 13Another alternative liquid feed assembly 106” is shown. Liquid feed assembly 106” is shown together with square membrane 20’. Liquid feed assembly 106” has three linear channels 1067, 1068, 1069 defined in matrix 1070. Each of linear channels 1067, 1068, 1069 feeds a corresponding liquid aerosol forming matrix from a reservoir (not shown) via a corresponding liquid aerosol forming matrix inlet 1071, 1072, 1073. Linear channels 1067, 1068, 1069 feed their respective liquid aerosol forming matrix into a corresponding linear region of membrane 20’. In an alternative embodiment (not shown), wicking material is positioned in each of linear channels 1067, 1068, 1069, wherein the wicking material for each channel is used to wet the corresponding liquid aerosol forming matrix of said channel.

[0142] although Figures 11 to 13 Not shown, but the liquid feed assemblies 106, 106', 106' include one or more micropumps to actively feed the liquid aerosol forming matrix to the membranes 20, 20'. The micropumps of the liquid feed assemblies 106, 106', 106'' will be coupled to a power source (e.g., ...). Figure 1 Power supply 103 shown - see Figure 1 (The dashed line in the diagram connects to the liquid feed assembly 106) and is powered by it.

[0143] For the purposes of this specification and the appended claims, unless otherwise stated, all figures representing quantities, quantities, percentages, etc., shall be understood to be modified by the term “about” in all cases. Furthermore, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges that may be specifically listed or not listed herein. Thus, in this document, the numeral “A” is understood to be “A” ± 10%. In this document, the numeral “A” may be considered to include a value within the general standard error of the measurement of the property modified by the numeral “A”. In certain instances used in the appended claims, the numeral “A” may deviate from the percentages listed above, provided that the amount of deviation from “A” does not materially affect the essential and novel features of the claimed invention. Furthermore, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges that may be specifically listed or not listed herein.

Claims

1. An aerosol generating apparatus, the aerosol generating apparatus comprising: A membrane having an aerosol generation zone, wherein the aerosol generation zone includes a plurality of nozzles, the plurality of nozzles being the only nozzles in the aerosol generation zone; as well as An actuator, the actuator being coupled to the membrane; The actuator is configured to excite the membrane to cause vibration of the membrane at one or more predetermined modal frequencies, so as to form a matrix aerosol from the liquid aerosol passing through the plurality of nozzles during use. More than 50% of the plurality of nozzles are positioned closer to the antinodes than the nodes of the membrane, wherein the antinodes and the nodes correspond to the membrane being excited at one or more predetermined modal frequencies of the membrane; The thickness of the membrane gradually increases from the center of the membrane to the peripheral edge of the membrane, or the thickness of the membrane gradually decreases from the center of the membrane to the peripheral edge of the membrane.

2. The aerosol generating apparatus according to claim 1, wherein the plurality of nozzles are non-uniformly distributed above the aerosol generating area.

3. The aerosol generating apparatus according to claim 1 or 2, wherein at least 60% of the plurality of nozzles are positioned in a region extending on either side of the antinode, the region being a region in which the displacement amplitude of the membrane at the antinode is at least 60% of the displacement amplitude of the membrane at the corresponding one or more predetermined modal frequencies.

4. The aerosol generating apparatus according to claim 3, wherein all of the plurality of nozzles are positioned in a region extending on either side of the antinode.

5. The aerosol generating apparatus according to claim 1 or 2, wherein the one or more predetermined modal frequencies include a first predetermined modal frequency of the membrane and a second predetermined modal frequency of the membrane, wherein the plurality of nozzles are positioned in a first intersection region and a second intersection region of the aerosol generating region, wherein: For the first cross region, the antinode corresponding to the first predetermined modal frequency of the membrane is close to the node corresponding to the second predetermined modal frequency of the membrane; as well as For the second cross region, the antinode corresponding to the second predetermined modal frequency of the membrane is close to the node corresponding to the first predetermined modal frequency of the membrane.

6. The aerosol generating apparatus according to claim 5, wherein all of the plurality of nozzles are positioned in the first intersection region and the second intersection region.

7. The aerosol generating apparatus according to claim 5, wherein: For the first cross region, the node corresponding to the second predetermined modal frequency is located in a first region extending on either side of the antinode corresponding to the first predetermined modal frequency, the first region being a region where the displacement amplitude of the membrane at the antinode is at least 60% of the displacement amplitude of the membrane at the antinode for the first predetermined modal frequency. as well as For the second cross region, the node corresponding to the first predetermined modal frequency is located in a second region extending on either side of the antinode corresponding to the second predetermined modal frequency, the second region being a region where the displacement amplitude of the membrane at the antinode is at least 60% of the displacement amplitude of the membrane at the antinode for the second predetermined modal frequency.

8. The aerosol generating apparatus according to claim 1 or 2, wherein the aerosol generating apparatus is configured to selectively apply and release constraints to the membrane in order to adjust the response of the membrane to the one or more predetermined modal frequencies.

9. The aerosol generating apparatus of claim 8, wherein the aerosol generating apparatus is configured to selectively apply and release the constraint along one or more portions of the periphery of the membrane.

10. The aerosol generating apparatus according to claim 1 or 2, wherein the actuator is configured to selectively excite different portions of the membrane.

11. The aerosol generating apparatus of claim 10, wherein the actuator comprises a plurality of actuator segments, each actuator segment being coupled to a different portion of the membrane.

12. The aerosol generating apparatus according to claim 1 or 2, wherein the actuator is configured to apply a modulated drive signal to the membrane to excite the membrane.

13. The aerosol generating apparatus according to claim 1 or 2, wherein the thickness of the membrane gradually decreases from the center of the membrane to the peripheral edge of the membrane.

14. The aerosol generating apparatus according to claim 1 or 2, wherein the thickness of the membrane gradually increases from the center of the membrane to the peripheral edge of the membrane.

15. An aerosol delivery system, the aerosol delivery system comprising: The aerosol generating apparatus according to any one of claims 1 to 14; The aerosol delivery system also includes: Liquid feed, operable to supply a liquid aerosol forming matrix to the membrane.

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