Aerosol-forming article and device of improved efficiency

Abstract

An aerosol-forming article for use in an aerosol-forming device, comprising a liquid reservoir configured to store a liquid aerosol-forming substrate, a liquid transfer element, comprising a liquid ingress surface fluidically connected to the liquid reservoir, a vapor egress surface fluidically connected to an aerosolization chamber, and a liquid transfer volume between the liquid ingress surface and the vapor egress surface configured to transfer liquid from the liquid ingress surface towards the vapor egress surface, at least two electrodes or at least two electrode receptacles configured to form a dielectric heating zone inside at least a part of the liquid transfer element, wherein the at least two electrode receptacles are each configured to receive an electrode of the aerosol-forming device when the aerosol-forming article is inserted into an aerosol-forming device for use, wherein at least the part of the liquid transfer element is arranged between the at least two electrodes or between the at least two electrode receptacles such that the liquid is guided from the liquid ingress surface through the dielectric heating zone caused by the at least two electrodes or the at least two electrode receptacles towards the vapor egress surface.

Description

[0001] AEROSOL-FORMING ARTICLE AND DEVICE OF IMPROVED EFFICIENCY

[0002] The present disclosure relates to an aerosol-forming article for use in an aerosol-forming device, an aerosol-forming device, particularly for use with the aerosol-forming article, and a system including the aerosol-forming article and device, and a method of heating a liquid aerosolforming substrate in an aerosol-forming article and / or an aerosol-forming device.

[0003] Aerosol-forming or aerosol-generating devices are typically designed as handheld devices that can be used by a user for consuming or experiencing, for instance in one or more inhalations or puffs, aerosol generated from an aerosol-forming substrate or an aerosol-forming article, for example by heating. The aerosol-forming devices of the present disclosure are mainly directed to the field of tobacco and tobacco-substitute products, for example electronic cigarettes, e-vapor devices, and / or vaporisers. The aerosol-forming devices of the present disclosure may also pertain to other types of inhalers, dispensers, or atomizers, for example inhalers, dispensers, or atomizers for medical applications.

[0004] Typical aerosol-forming systems can be designed as one-part systems or devices including an aerosol-forming device that can be operated by a user to generate aerosol. Alternatively, aerosol-forming systems can be designed as two-part systems or devices comprising an aerosolforming device and a companion device for storing and / or charging the aerosol-forming device. In either design or configuration, the aerosol-forming system or device can be used by a user for consuming or inhaling, for instance in one or more inhalations or puffs, aerosol generated based on heating an aerosol-forming article or substrate couplable to the aerosol-forming system. In the context of the present disclosure, an aerosol-forming device can refer to both a one-part device and a two-part device, unless explicitly specified otherwise.

[0005] The aerosol-forming article, also referred to as aerosol-generating article, cartridge, capsule, reservoir, or pod, can comprise an aerosol-generating or aerosol-forming substrate, for example a liquid aerosol-forming substrate, for example a liquid aerosol-forming substrate including nicotine or a nicotine substitute. The aerosol-forming article may be configured in shape and size to be inserted at least partially into the aerosol-forming device or system. In conventional systems or devices, the aerosol-forming article is usually formed as a pod, cartridge, capsule, or reservoir, that can be at least partly inserted into a receiving space of the aerosol-forming device for aerosol consumption.

[0006] Exemplary aerosol-forming substrates can comprise liquid substrate material, containing one or more active ingredients and one or more aerosol formers. The substrate material can, for example, be assembled, often with other elements or components, to form a substantially podshaped aerosol-forming article. Such aerosol-forming article can be configured in shape and size to be inserted at least partially into a receiving space of the aerosol-forming device. The aerosolforming device may comprise a heating element or heater device for heating the substrate of theaerosol-forming article to cause vaporization. The heating element or heater device may be part of the aerosol-forming article and / or the aerosol-forming device. Alternatively or additionally, aerosol-forming substrates can comprise one or more liquids and / or solids, which can, for example, be supplied to the aerosol-forming device in the form of a cartridge or container. Corresponding exemplary aerosol-forming articles can, for example, comprise a cartridge containing or fillable with the liquid and / or solid substrate, which can be vaporized during aerosol consumption by the user based on heating the substrate and / or liquid. Usually, such cartridge or container can be coupled to, attached to or at least partially inserted into the aerosol-forming device. Alternatively, the cartridge may be fixedly mounted to the aerosol-forming device and refilled by inserting liquid and / or solid into the cartridge. The aerosol generated from the aerosolforming substrate or article may comprise or include one or more of nicotine, aroma, sugar, moisturising agent, botanicals such as cannabinoids, preservative, flavouring, for example cocoa, liquorice, menthol and lactic acid or other additives. The aerosol generated from the aerosolforming substrate or article may additionally or alternatively comprise one or more pharmaceutical agents or drugs and may include one or more adjuvants. In addition, the aerosol-forming substrate can further include one or more aerosol formers, for example but not limited to propylene glycol (PG), vegetable glycerin (VG), polyethylene glycol (PEG), glycerol esters, triacetin, or other.

[0007] For generating the aerosol during use or consumption, heat can be supplied by a heating element, heater device or heat source to heat at least a portion or part of the aerosol-forming substrate. The heating element, heater device or heat source can be arranged in the handheld device or a handheld part of the aerosol-forming device. Alternatively or additionally, at least a part of or the entire heating element or heater device or heat source can be fixedly associated with or arranged within an aerosol-forming article, for instance in the form of a cartridge, which can be attached to and / or powered by the handheld device or handheld part of the aerosolforming device.

[0008] Conventionally, resistive heating may be used to heat the liquid substrate. However, the present disclosure relates to dielectric or microwave heating achieved through an alternating electrical field using electrical energy supplied via, drawn from or stored in an energy storage or battery of the aerosol-forming device. As used herein, a battery of the aerosol-forming device can generally refer to an energy storage of the aerosol-forming device configured to store electrical energy. Accordingly, the term energy storage can include one or more batteries, one or more capacitors, one or more accumulators or other types of energy storage. Also, any reference to a battery herein can include a plurality of batteries.

[0009] Typically, aerosol-forming devices comprise an energy storage, for example a battery, providing the electrical energy needed to operate the aerosol-forming device and especially for heating the aerosol-forming substrate and / or article, for example to generate aerosol for one ormore user puffs or inhalations, using one or more aerosol-forming articles. The battery may, for example, be a lithium-ion battery.

[0010] According to aspects of the present invention, aerosol-forming devices may form aerosol by heating a liquid aerosol-forming substrate, the constituents of which may be provided as a liquid from the start or which may at least partly be extracted from solid components included in the aerosol-forming article. Typically, the liquid is transported to the heating device by a liquid transfer element, for example a wicking element. The transport of liquid may be caused by capillary action due to small flow paths in the liquid transfer element, by gravity, or by other means, for example by pumping and / or an actuator, or a combination of these types of liquid transport. To achieve enough flow of the liquid aerosol-forming substrate to the heating device to be able to provide the user with the desired aerosol for consumption, liquid transfer elements of sufficient size are necessary, for example defined as a cross-sectional area of a flow.

[0011] With some aerosol-forming devices using dielectric heating, it is possible that a portion of the volume of the liquid transfer element is heated at locations where it is soaked by the liquid aerosol-forming substrate at a certain distance from the vapor egress surface, leading to undesired volumetric heating of the liquid aerosol-forming substrate, and potentially creating vapor bubbles that can be trapped at undesired locations, causing ejection of liquid droplets from the vapor egress surface of a liquid transfer element.

[0012] In addition, devices using dielectric heating may heat other components of the aerosolforming article or device as well other than just the liquid aerosol-forming substrate. For example, separation walls, aerosol flow pathways, and device walls may be arranged juxtaposed to the electric fields caused by the dielectric heating or even at least partly in the heating zone. Heating these components also leads to a loss of energy and can potentially cause undesired substances.

[0013] It may therefore be desirable to provide for an improved aerosol-forming article and / or device in which heating of liquid aerosol-forming substrate is achieved with more efficiency. In particular, unnecessary heating of the wicking element and / or other components of the article and / or device is to be avoided.

[0014] It is also desirable to have an aerosol-forming article, i.e. a cartridge, capsule, container, or pod, without any electrodes.

[0015] These advantages may be achieved by the features described herein.

[0016] According to an aspect of the present invention, there is provided an aerosol-forming article for use in an aerosol-forming device, comprising a liquid reservoir configured to store a liquid aerosol-forming substrate, a liquid transfer element, comprising a liquid ingress surface fluidically connected to the liquid reservoir, a vapor egress surface fluidically connected to an aerosolization chamber, and a liquid transfer volume between the liquid ingress surface and the vapor egress surface configured to transfer liquid from the liquid ingress surface towards the vapor egresssurface, at least two electrodes or at least two electrode receptacles forming or configured to form a dielectric heating zone inside at least a part of the liquid transfer element, wherein the at least two electrode receptacles are each configured to receive an electrode of the aerosol-forming device when the aerosol-forming article is inserted into an aerosol-forming device for use, wherein at least the part of the liquid transfer element is arranged between the at least two electrodes or between the at least two electrode receptacles such that the liquid is guided from the liquid ingress surface through the dielectric heating zone caused by the at least two electrodes or the at least two electrode receptacles towards the vapor egress surface.

[0017] In the context of the present disclosure, the aerosol-forming device and / or the aerosolforming system may be a portable device and / or system. It may be battery powered. Particularly, the aerosol-forming device and / or the aerosol-forming system may be pocket-size, hand-held, suitable for one-hand use and / or may weigh less than 300 g, preferably less than 200 g. It may be shaped and / or sized to fit snugly into a user’s hand. It may be carried in jacket and / or trouser pockets. Particularly, the aerosol-forming device and / or the aerosol-forming system may be configured to provide aerosol for human inhalation and / or human consumption, particularly inhalation and / or consumption through the mouth.

[0018] That the at least two electrodes are configured to form or cause a dielectric heating zone may mean that they are configured to establish an alternating electric field at or in the heating zone, for example using an oscillation circuit as described herein. The alternating electric field may then lead to dielectric heating of a liquid aerosol-forming substrate of the aerosol-forming article which may be inserted into the heating zone. In other words, the dielectric heating zone may be arranged inside at least a part of the liquid transfer element. That the at least two electrode receptacles are configured to form or cause a dielectric heating zone may mean that the electrode receptacles are configured and / or arranged that each may receive an electrode, and that then an alternating electric field may be established by the electrodes to form the heating zone. The position, size and therefore function of the heating zone in heating a liquid aerosol-forming substrate in the heating zone may therefore be facilitated and / or predefined by the electrode receptacles.

[0019] Moreover, according to at least some embodiments described herein, for example the embodiments using the electrode receptacles in the aerosol-forming article, given the advantages provided by the dielectric heating allowing for non-contact heating, it is possible to provide for an aerosol-forming article, i.e. a cartridge or pod, that does not have any heating elements. Such aerosol-forming articles also do not require any electric terminals that are needed to provide electric power to the cartridge heating elements, for example as seen in the state-of-the-art coil-and-wick or mesh-and-wick heater elements in e-vapor cartridges. The electrodes that can provide for the alternating electric field can be part of the cartridge holder, and the oscillator circuitis thereby fully comprised in the cartridge holder. This also allows making cartridges or pods that do not use any metal parts, which is the case for both resistive heated e-vapor cartridges, and inductively-heated e-vapor cartridges, and thereby it is possible to avoid contamination of the liquids or vapors over time by metal particles and residue. This may also lead to less generation of Harmful and Potentially Harmful Constituents (HPHC) by avoiding metals being in contact with liquid over a long time of the use of the cartridge. In addition, a cartridge or pod can be provided that can be easily recyclable, using a less diverse material composition for the manufacturing. An additional advantage is the simplified design of the system with a cartridge that does not require any electromagnetic shielding, but the shielding can be fully incorporated into the cartridge holder.

[0020] The liquid transfer element may be embodied as a wicking element. It may provide liquid transport from the liquid ingress surface towards the vapor egress surface by capillary action, by gravity, or by a combination of both. Alternatively or additionally, an actuator or a pump may be used to actively move the liquid aerosol-forming substrate from the liquid ingress surface towards the vapor egress surface. The liquid transfer element may be arranged at least partly in the heating zone, particularly with the vapor egress surface. The heating zone may be defined by the portion of the liquid transfer element that is exposed to the alternating electric field caused by the electrodes that is sufficiently strong to cause vaporization of the liquid aerosol-forming substrate. The electrodes may, for example, be arranged in proximity of, at, on, or in contact with the walls of the article that enclose the liquid transfer element so that the heating zone encompasses or substantially encompasses the vapor egress surface of the liquid transfer element. For example, it may be provided that the electrodes and walls of the aerosol-forming article enclosing the liquid transfer element are configured and / or arranged such that there is a press-fitted or interference-fitted arrangement such that the electrodes are slightly pressed against the walls when the aerosol-forming article is inserted into the holder, to minimize the distance between the electrodes and provide efficient dielectric heating. Thereby, the liquid aerosol-forming substrate can be reliably and completely or substantially completely vaporized in the heating zone, even if some of the liquid aerosol-forming substrate may exit the liquid transfer element, i.e. the vapor egress surface, in liquid form. In effect therefore, also in this case, vapor formed from the liquid aerosolforming substrate at the heating zone and thus at the vapor egress surface enters the aerosolization chamber from the heating zone. The liquid transfer element may be at least partly arranged between the at least two electrodes. Therefore, when the liquid is heated by the dielectric heating caused by the alternating electric field by the electrodes, the temperature of the liquid may increase until the vaporization temperature of the one or more components of the liquid is reached inside the liquid transfer element, more specifically at the vapor egress surface. At this point, at least a part of the liquid turns into vapor. For example, the liquid may have various components or constituents with different vaporization temperatures. For example, an aerosol-former and / or a carrier liquid may be vaporized and may carry out one or more active agents in the vapor, so that an inhalable aerosol may be formed in the aerosolization chamber with the one or more active agents, e.g. for example nicotine. Generally, the liquid transfer element may be fully soaked with liquid aerosol-forming substrate all the way to the vapor egress surface. Once dielectric heating occurs, preferably with the strongest intensity of the RF electric field zone at the vapor egress surface, the liquid may be vaporized at or in close proximity to the vapor egress surface, such that the vaporized liquid will exit the liquid transfer element by the vapor egress surface. Preferably only very little or a strongly reduced creation of vapor bubbles inside the liquid transfer element away from the vapor egress surface is caused. Such bubbles could be trapped and cause ejection of non-vaporized liquid from the vapor egress surface, which should be avoided to prevent liquid from dripping from the device.

[0021] The vapor exiting the heating zone may be mixed with incoming air from an air inlet in the aerosolization chamber. For this, the aerosolization chamber may be fluidically connected to the outside environment through an air inlet and air flow path. When the user draws or puffs on the cartridge, i.e. the aerosol-forming article, that is in operative connection with the aerosol-forming device or on a mouthpiece fluidically connected to the aerosol-forming article downstream of the aerosolization chamber, outside air is drawn into the device and through the aerosolization chamber, where it is mixed with the vapor exiting the vapor egress surface. The vapor cools off and small droplets may be formed, ultimately leading to the forming or generation of aerosol from the mixture of vapor and air. This may then be consumed by the user through inhalation.

[0022] The liquid ingress surface may be defined by a surface area of the liquid transfer element directed towards the liquid reservoir or a liquid channel that is fed by liquid from the liquid reservoir. Therefore, the liquid ingress surface may be in direct contact with the liquid aerosolforming substrate stored in the liquid reservoir. The vapor egress surface may be defined as the surface area of the liquid transfer element directed towards the aerosolization chamber. Therefore, the vapor egress surface may be in direct contact with the air, vapor and / or aerosol in the aerosolization chamber. As explained in more detail later, the liquid transfer element may be or may comprise a porous material or a material comprising capillaries or other small flow pathways, forming a plurality of contiguous liquid pathways from the liquid ingress surface to the vapor egress surface. It is also possible that the liquid transfer element is made from a solid body having a plurality of parallelly-arranged flow channels, for example flow channels having dimensions to cause a capillary flow, each leading from the liquid ingress surface to the vapor egress surface. Therefore, the liquid ingress surface and / or the vapor egress surface can be an uneven or rough surface. However, the liquid ingress surface and / or the vapor egress surface may be, for the purposes herein, be understood as a face end or face end surface of the liquid transfer element at the specific sides constituting the liquid ingress surface and / or the vaporegress surface. For example, the liquid ingress surface and / or the vapor egress surface may refer to an area and / or surface and / or plane defining or being defined by said end faces of the liquid transfer element. For example, the liquid ingress surface and / or the vapor egress surface may refer to an area and / or plane parallel to and / or located at and / or following the shape, particularly the macroscopic shape, of the respective end face of the liquid transfer element.

[0023] The aerosol-forming article and / or aerosol-forming device according to aspects of the present disclosure may be configured to be used with dielectric heating. The electrodes may be part of a dielectric heating arrangement, for example including an oscillator which may provide a radio frequency, RF, voltage across the electrodes, to cause the generation of an RF electric field between the electrodes, as explained in more detail below. An alternating electric field may be established between at least two electrodes which together may form a capacitor or load capacitor. The heating zone may therefore be formed at least partly between the at least two electrodes. The heating zone may reach beyond the space between the electrodes, for example for up to several millimetres, for example for up to 3 mm or up to 2 mm or up to 1 mm. The electrodes may be part of and / or may be arranged in the aerosol-forming article or in the aerosolforming device. In other words, the electrodes may be part of and / or may be arranged on the side of the aerosol-forming article or on the side of the aerosol-forming device. This means that either the aerosol-forming article or the aerosol-forming device may be free of the at least two electrodes, for example free of any electrodes configured for dielectric heating. When the electrodes are part of the aerosol-forming article, the aerosol-forming device may comprise electrode connection elements, i.e. electrical connections, to electrically connect the electrodes of the removable aerosol-forming article to the aerosol-forming device, for interconnection with the oscillator, power system and / or power supply of the aerosol-forming device. Apart from the electrodes, the aerosol-forming article may also comprise other passive components of the feedback loop, for example one or more inductors. Alternatively, the feedback loop, for example the one or more inductors, are arranged in the aerosol-forming device, and the aerosol-forming article may exclusively comprise the electrodes and their electrical connections. On the other hand, when the electrodes are part of the aerosol-forming device, the aerosol-forming article may comprise an electrode receptacle for each of the electrodes of the aerosol-forming device. The electrode receptacles may be configured to receive the electrodes of the aerosol-forming device. For this, the electrode receptacles may comprise a structural part, for example a housing or casing part which may be configured to receive the electrodes and which may at least partly or completely surround the electrodes when the aerosol-forming article is inserted into the aerosolforming device. However, the electrode receptacles may also simply be formed by an open space, a recess or a hollowed-out volume in the aerosol-forming article configured in shape and size to receive the electrodes. The electrode receptacles may therefore be positioned inside the aerosol-forming article so that, when the electrodes have been received in the receptacles, the at least one heating zone established by the electrodes is located at the designated position. The electrodes and / or the electrode receptacles may extend against the direction of insertion of the aerosol-forming article into the receiving space of the aerosol-forming device. In other words, a longitudinal axis of the electrodes and / or the electrode receptacles may be parallel to the direction of insertion of the aerosol-forming article into the receiving space of the aerosol-forming device.

[0024] The heating zone may contain at least part of the liquid transfer element or liquid transfer volume. The liquid aerosol-forming substrate may be guided directly through the heating zone, i.e. into the area where the alternating electric field is caused by the at least two electrodes, entering the heating zone on one side and then exiting the heating zone as vapor. The heating zone may contain at least part of the liquid transfer element or liquid transfer volume. For example, the liquid aerosol-forming substrate may exit the liquid transfer element as vapor at the vapor egress surface. Alternatively or additionally, the liquid aerosol-forming substrate may be vaporized after exiting the liquid transfer element at the vapor egress surface as liquid. By performing heating only at the side of the liquid transfer element comprising the vapor egress surface, a constant, sufficient vaporization of liquid aerosol-forming substrate may be achieved through the heating zone, and the heat transfer to the liquid aerosol-forming substrate is efficient and has reduced losses, for example because only a little of the liquid transfer element needs to be heated, thereby saving energy and increasing battery life.

[0025] For example, to further increase this efficiency, it may be provided that the components are arranged and / or designed so that the flow direction or effective flow direction of the liquid aerosolforming substrate and / or vapor does not change, i.e. stays the same, during the transport of the liquid and / or through the heating zone. In other words, it may be provided that an effective flow direction of liquid aerosol-forming substrate and / or vapor formed from the liquid aerosol-forming substrate through the heating zone and / or from the liquid ingress surface to the vapor egress surface is unidirectional, for example substantially orthogonal to a main direction of the strongest amplitudes of an alternating electrical field in the dielectric heating zone. The direction of the strongest amplitudes of the alternating electrical field in the dielectric heating zone may be from one electrode to the other, the field lines always beginning and ending perpendicular to the surface of the electrodes, even if the design of the electrodes also leads to curved field lines. The effective flow direction may be defined as the overall direction in which a fluid predominantly moves through a medium, in this case the liquid transfer element, when observed at a larger scale, averaging out small-scale variations in flow paths. In other words, the effective flow direction may be defined in a quantitative way as the direction in which liquid aerosol-forming substrate enters the heating zone and in which the vapor formed from the liquid aerosol-forming substrate exits the heating zone into the aerosolization chamber and / or as the direction in whichthe liquid aerosol-forming substrate enters the liquid transfer element, i.e. at the liquid ingress surface, is transported through the liquid transfer element and / or liquid transfer volume and exits the liquid transfer element and / or liquid transfer volume, i.e. at the vapor egress surface. While on a microscopic scale, the liquid and / or vapor may flow in different directions, for example in turbulent flow or variable directions of a capillary flow in a porous body, these flow directions may be averaged out in the effective flow direction, leaving only the direction of quantitative transport. The liquid aerosol-forming substrate and the vapor formed from the liquid aerosol-forming substrate may flow between and / or through the at least two electrodes and / or electrode receptacles, for example in a way that in a direction orthogonal to the flow direction, for example in a direction orthogonal to the effective flow direction, the liquid and / or vapor is always between the opposing electrodes and / or electrode receptacles. By providing a unidirectional flow, particularly through the heating zone, the liquid entering the heating zone may be efficiently preheated by the alternating electric field and then, downstream in the heating zone, may be vaporized, the vapor also being transported off in the same direction. In this way, no or only little heat is lost to other components of the device, for example to parts of the liquid transfer element outside, particularly upstream, of the heating zone, and / or to volumes of the liquid aerosol-forming substrate which are not about to undergo heating and vaporization in the heating zone. Therefore, in effect, no or comparatively little heating energy is lost and the overall efficiency of the aerosolforming device as well as battery life is increased, leading to a more efficient use of the alternating electric field for the dielectric heating to cause sufficient volumetric heating power to cause rapid vaporization. Another advantage lies in the fact that the volumetric heating power of the liquid aerosol-forming substrate by dielectric heating will be the largest where the electric field amplitude is the highest, and therefore the liquid transfer element and electrodes and / or electrode receptacles may be designed that the strongest volumetric heating power is caused at the furthest downstream portions of the flow, particularly the flow through the liquid transfer element, right at the liquid egress surface, as will be described in more detail below. In this way, vaporization of liquid away from the vapor egress surface can be avoided, which might lead to ejection of still liquid substrate from the vapor egress surface by the expanding vapor. In this way, the amount of liquid substrate, which has not been vaporized, and which reaches the mouthpiece may be minimized.

[0026] To avoid heating any more components or parts of components of the aerosol-forming device than absolutely necessary for the provision of the vapor and ultimately the aerosol, it may be provided that no other components other than the liquid transfer element or parts of the liquid transfer element, potentially at least a part of the aerosolization chamber, and potentially a housing component separating the liquid transfer element from the electrodes or electrode receptacles, for example a wall component or wall, are arranged inside of the heating zone, e.g.are exposed to a meaningfully strong alternating electric field. In other words, it may be provided that the heating zone is free of components other than the liquid transfer element or parts of the liquid transfer element, potentially at least a part of the aerosolization chamber, and potentially a housing component separating the liquid transfer element from the electrodes or electrode receptacles, for example a wall component or wall. This again ensures an increased efficiency of the heating. Also, the liquid transfer element may be free of aerosol flow pathways. This may mean that no aerosol is guided through a pathway inside or at least partially inside the liquid transfer element. Only vapor may therefore be transported in the liquid transfer element, which is then aerosolized when mixing with air in the aerosolization chamber or space.

[0027] The dielectric heating zone may be defined by the arrangement of the at least two electrodes and / or electrode receptacles. Particularly, the dielectric heating zone may be defined as the volume in which an alternating electrical field of sufficient strength for pre-heating and / or heating and / or vaporization of the liquid aerosol-forming substrate is achieved. The dielectric heating zone may be arranged between the electrodes and / or electrode receptacles and may also reach beyond the volume or space between the electrodes and / or electrode receptacles, for example for a few millimetres, for example for up to 3 mm or up to 2.5 mm or for up to 2 mm or up to 1.5 mm or for up to 1 mm or up to 0.5 mm. The heating zone and / or the volume or space between the electrodes and / or electrode receptacles may comprise parts of the liquid transfer element and / or the aerosolization chamber or aerosolization space. The vapor egress surface of the liquid transfer element may be arranged inside the heating zone and / or the volume or space between the electrodes and / or electrode receptacles and may form an outer surface of the liquid transfer element towards the aerosolization chamber or space. The volume between the electrodes and / or electrode receptacles may partly contain an open space which may be fluidically connected to or be part of the aerosolization chamber and may partly contain a part of the liquid transfer element, for example comprising the vapor egress surface. The volume between the electrodes and / or electrode receptacles may even be filled, for example completely filled, by the liquid transfer element. In this case, the volume between the electrodes and / or electrode receptacles may only contain a part of the liquid transfer element. For instance, the volume between the electrodes and / or electrode receptacles may end with the vapor egress surface of the liquid transfer element, which may be fluidically connected to the aerosolization chamber. These particular arrangements ensure efficient heating and prevent liquid from exiting the heating zone at the vapor egress surface, thereby ensuring complete vaporization of the liquid aerosol-forming substrate.

[0028] The liquid transfer element may be made of or may comprise a wicking material, for example a porous or fibrous material or a material comprising channels or microchannels, for example a porous ceramic material, for example a porous silicon ceramic material. The liquid transferelement can also comprise a plurality of fluidically parallelly arranged flow channels, leading from liquid ingress surface to the vapor egress surface. The liquid transfer element and / or the wicking material may be configured to cause capillary flow of the liquid aerosol-forming substrate, particularly in the effective flow direction. The liquid transfer element can also be arranged to cause gravitational flow of the liquid to the heating zone, or a combination of gravitational and capillary flow. For example, the liquid transfer element may be made of or may comprise food and / or medical grade silicate-based or clay-based ceramic. Other suitable materials may include alumina oxide ceramics. As another example, a material used for the liquid transfer element can be glass-based. Glass is an inert material that does not degrade with repeated heating cycles and also has a low relative permittivity or dielectric constant, thereby absorbing substantially less dielectric energy than a liquid aerosol-forming substrate or e-liquid. For example, the material for the glass can be primarily vitreous silica or quartz glass. The liquid transfer element may have a porosity of from 50% to 70%, for example from 55% to 65%, for example of 60%. An average pore size may be from 10 pm to 50 pm, for example from 15 pm to 40 pm or from 20 pm to 30 pm. The liquid transfer element may also have a variable porosity, for example a higher porosity at the liquid ingress surface and a lower porosity at the vapor egress surface or a lower porosity at the liquid ingress surface and a higher porosity at the vapor egress surface. Analogously, the liquid transfer element can be made of a plurality of flow channels having a larger cross-sectional flow area at the vapor egress surface as compared to the liquid ingress surface or having a larger cross-sectional flow area at the liquid ingress surface as compared to the vapor egress surface. In other words, the porosity of the liquid transfer element may diminish or become smaller or increase or become bigger, either stepwise or continually, in a direction from the liquid ingress surface towards or to the vapor egress surface, for example in the direction of the effective flow direction as described herein. This change in porosity or overall cross-sectional flow surface allows to facilitate the evacuation of vapor of the liquid aerosol-forming substrate that expands relative to its liquid state. All of these features may be used to improve flow parameters. In case flow channels are used, a cross-section of the flow channels can increase from the liquid ingress surface to the vapor egress surface.

[0029] As already mentioned, only a part of the liquid transfer volume or the liquid transfer element may be arranged in or inside the heating zone and / or the volume between the electrodes. For example, a maximum of 50% or a maximum of 40% or a maximum of 30% or a maximum of 20% or a maximum of 15% or a maximum of 10% of the liquid transfer volume or the liquid transfer element may be arranged in or inside the dielectric heating zone and / or the volume between the electrodes. In this way, heating or volumetric heating of a part of the liquid transfer volume or the liquid transfer element not necessary for preheating and vaporizing the liquid aerosol-forming substrate is avoided. In other words, in this way, only a small part of the liquid transfer volume orliquid transfer element is heated which is necessary for efficient preheating and vaporization of the liquid aerosol-forming substrate, whereas areas not contributing to vapor and ultimately the aerosol flow are not heated, saving energy and improving efficiency.

[0030] The heating zone may define a heating volume in which the liquid aerosol-forming substrate is preheated and vaporized while flowing through the heating zone. The heating volume may also be defined as the volume in which an alternating electrical field of sufficient strength for preheating and / or heating and / or vaporization of the liquid aerosol-forming substrate is achieved. The dimensions and features as previously described for the heating zone may also be applicable to the heating volume. Both the preheating and the vaporization of the liquid aerosol-forming substrate is implemented, for example exclusively implemented, inside of the heating volume. That the preheating and the vaporization of the liquid aerosol-forming substrate is exclusively implemented inside of the heating volume may mean that no active heating of liquid aerosolforming substrate may be implemented anywhere outside of the heating volume. While it may still be possible that heat is passively transported to liquid outside of the heating volume, for example by heat conduction, no active heating is implemented.

[0031] To effectively and completely vaporize the liquid aerosol-forming substrate and simultaneously avoid unnecessary heating of liquid aerosol-forming substrate which is not about to be vaporized, the highest heating power may be directed at the vapor egress surface. The highest heating power is achieved where the amplitude of the alternating electric field reaches its maximum. Positioning this location or volume of space at the vapor egress surface may be achieved by suitable electrode shapes and / or their arrangement relative to each other, as explained herein. Thus, the at least two electrodes may be arranged, shaped and / or configured to generate a maximal or maximum electric field amplitude at the vapor egress surface and / or in a volume of space up to 2 mm or up to 1 mm before and / or behind the vapor egress surface, for example in a direction orthogonal to a direction of an alternating electrical field in the dielectric heating zone. In other words, the vapor egress surface may be arranged at most 2 mm or at most 1 mm away from the location in which the amplitude of the alternating electric field reaches its maximum. The distances mentioned may also be measured in a normal direction of the vapor egress surface and / or in the effective flow direction or an extrapolation of the effective flow direction of the liquid aerosol-forming substrate. Particularly, the at least two electrodes may be arranged, shaped and / or configured so that the amplitude of the alternating electric field reaches its maximum at or substantially at or directly at the vapor egress surface.

[0032] To further reduce the necessary energy for heating, it may be provided that the distance between the electrodes or the electrode receptacles is made small. For example, the heating volume of the heating zone may be made small so that higher heating temperatures may be reached by the same voltage used for the dielectric heating. The dielectric heating zone and / orthe heating volume may therefore be implemented as a constriction and / or a bottleneck, for example in that the liquid transfer element tapers towards the dielectric heating zone and / or the heating volume and / or the vapor egress surface. In other words, it may be provided that a cross-sectional area of the liquid transfer element in the dielectric heating zone is smaller than a cross-sectional area of the liquid transfer element outside the dielectric heating zone, for example a cross-sectional area of the liquid transfer element upstream and / or downstream of the dielectric heating zone. Upstream and / or downstream as used herein may refer to the effective flow direction of the liquid and / or vapor as defined above. The cross-sectional areas may be measured in a plane perpendicular to the effective flow direction. The cross-sectional area of the liquid transfer element may be the smallest in the dielectric heating zone and / or the heating volume. The liquid ingress surface may be larger than the vapor egress surface and the liquid transfer element may be tapered towards the vapor egress surface. In this way, the volume in which high temperatures need to be reached can be made small, reducing energy costs and increasing efficiency.

[0033] In general, the at least two electrodes or the at least two electrode receptacles may be arranged in parallel to each other. In this way, the electric field strength may be approximately uniform throughout the heating zone except for fringe effects, and heating is also uniform. In an alternative embodiment, the at least two electrodes or the at least two electrode receptacles may be at least partly arranged obliquely to each other such that the dielectric heating zone is tapered towards the vapor egress surface, particularly wherein a constriction and / or bottleneck is formed by the vapor egress surface. In other words, the at least two electrodes or the at least two electrode receptacles may be arranged non-parallelly to each other, particularly in a way that they are further apart from each other at the entrance of the heating zone and that they are closer together at the outlet of the heating zone. In this case, the electric field strength is strongest where the distance between the electrodes and / or electrode receptacles is smallest and drops against the effective flow direction. The most heating power is therefore applied at or in direct vicinity of the vapor egress surface and / or outlet of the heating zone, facilitating reliable vaporization of the liquid aerosol-forming substrate before any liquid reaches the aerosolization chamber. The reduced field strength upstream of the vapor egress surface may be used for preheating the liquid aerosol-forming substrate before it is then vaporized at the point of highest field strength.

[0034] In the case of a rounded liquid transfer element and / or the vapor egress surface, but also in other cases, the at least two electrodes may be configured and / or arranged with respect to each other such that the volume between the at least two electrodes forms a constriction on a side facing the vapor egress surface. The at least two electrodes may be configured and / or arranged with respect to each other such that the distance between the at least two electrodes is smallest where the distance of the at least two electrodes to the vapor egress surface is smallest.In other words, a bottleneck between the electrodes is formed in close proximity or in the closest possible proximity to the vapor egress surface. I.e., the bottleneck may be directed towards the vapor egress surface. For example, when the electrodes have a rectangular cross-section, they may be tilted with respect to each other so that a bottleneck is formed between the closest corners of the rectangular cross-section. These corners may then be the ones directed towards the vapor egress surface. The strength of the electric field may be strongest where the distance between the electrodes is smallest. By arranging the electrodes in this way, the volume of space with the strongest electric field may be brought close to or may comprise the vapor egress surface, facilitating reliable vaporization of the liquid aerosol-forming substrate.

[0035] The at least two electrodes or the at least two electrode receptacles may comprise a planar or rounded surface towards the dielectric heating zone. For example, the electrodes may be implemented as planar or rounded metal strips. In the case of non-parallel arrangement to each other, the at least two electrodes or the at least two electrode receptacles may be arranged such that the smallest distance between them coincides with the vapor egress surface. In other words, the heating zone may taper towards the vapor egress surface. By tailoring the dimensions and the form of the electrodes and / or electrode receptacles to the specific use case, a desired combination of preheating power and heating power at the point of the strongest field strength, where the liquid aerosol-forming substrate is vaporized, may be achieved.

[0036] As mentioned, it may be advantageous to make the distance between the electrodes and / or the electrode receptacles small, particularly the smallest distance at a constriction or bottleneck formed by the electrodes and / or the electrode receptacles. The at least two electrodes or the at least two electrode receptacles may therefore be arranged such that a distance between them, particularly at the vapor egress surface or on a side oriented towards the vapor egress surface, is at most 2 mm or at most 1.75 mm or at most 1.5 mm or at most 1.25 mm or at most 1 mm. Particularly, an extension of the vapor egress surface between the at least two electrodes or the at least two electrode receptacles is at most 2 mm or at most 1.75 mm or at most 1.5 mm or at most 1.25 mm or at most 1 mm. Using these dimensions, a high heating power may be achieved with minimal energy consumption.

[0037] The aerosol-forming article may further comprise an aerosolization chamber arranged in fluid connection to the vapor egress surface. The aerosolization chamber may, for example, be formed by a part of the housing of the aerosol-forming article and / or the containment walls as mentioned later. This may also apply to the liquid reservoir, which may also be formed by a part of the housing of the aerosol-forming article and / or the containment walls. A constriction or bottleneck may be formed between the liquid reservoir and the aerosolization chamber. The constriction may be narrowest at the vapor egress surface and / or the dielectric heating zone. In this way, a large volume of the liquid transfer element is provided for transporting liquid into thesmall heating zone, where little power is used to achieve high temperatures, and vapor may leave the heating zone into a larger volume of the aerosolization chamber. Such an arrangement has advantageous effects on the flow parameters and therefore on the continuous provision of high quality aerosol for the user.

[0038] The at least two electrodes and / or the at least two electrode receptacles may be separated from the liquid transfer element by a housing part, for example a containment wall. For example, the housing part or containment wall may be part of the electrode receptacles. Therefore, the aerosol-forming article may further comprise two containment walls between the at least two electrodes or the at least two electrode receptacles, wherein the liquid transfer element may be arranged between the two containment walls, for example wherein the two containment walls are part of a housing of the liquid reservoir and / or the aerosolization chamber. In this way, contact between the electrode and the liquid may be avoided.

[0039] As the presence of the containment walls increases the distance of the electrodes from each other, heating efficiency may be increased by implementing thin containment walls. For example, the two containment walls may each have a thickness of at most 0.8 mm or at most 0.7 mm or at most 0.6 mm or at most 0.5 mm or at most 0.4 mm or at most 0.3 mm or at most 0.2 mm or at most 0.1 mm, or at most 0.05 mm. Particularly, these thicknesses apply to the containment walls in the volume between the electrodes and / or electrode receptacles, i.e. in the heating zone or heating volume. Outside of the heating zone or the heating volume, the housing or containment walls may have a different thickness and may, for example, be thicker than in the heating zone or the heating volume.

[0040] In summary, the aerosol-forming article may be very slim or thin in the region of the heating zone, where, for example, only the liquid transfer element, the containment walls and the electrodes and / or electrode receptacles may be arranged. Due to the small dimensions of the aerosol-forming article in this area, there is a risk that the article may be easily damaged or broken apart. Therefore, it may be provided that the aerosol-forming article may further comprise an outer shell or protective shell, wherein the outer shell may be arranged to cover at least the at least two electrodes or the at least two electrode receptacles. In other words, the outer shell may be arranged on the opposite side of the electrodes as the heating zone. The outer shell may be arranged distanced from the electrodes and / or the electrode receptacles and / or may be an outer housing of the aerosol-forming article. For instance, the outer shell may provide the aerosolforming article with an outer shape and / or outer contour that is complementary to an inner shape and / or contour of a receiving space of the aerosol-forming device configured to receive the aerosol-forming article. The outer shell of the aerosol-forming article may therefore provide a snap-fit or form-fit with the aerosol-forming device and may simultaneously provide protection for otherwise easily breakable or damageable parts of the article. The shape or outer shape of theaerosol-forming article may be oblong and / or elongated, for example in the insertion direction, and may comprise rounded or angled corners.

[0041] According to the present disclosure, at least one heating zone is provided by the at least two electrodes and / or electrode receptacles. However, additional heating zones may be provided by adding more electrodes and / or electrode receptacles. For example, the aerosol-forming article may comprise at least one additional electrode or at least one additional electrode receptacle configured to receive an electrode of the aerosol-forming device when the aerosol-forming article is inserted into an aerosol-forming device for use. At least one additional dielectric heating zone may be formed and / or established by the at least one additional electrode and another electrode or by the at least one additional electrode receptacle and another electrode receptacle. In this embodiment, therefore, at least one electrode or electrode receptacle may be used twice, i.e. may be used to establish two heating zones. This may mean that, in use, at least one electrode is used to establish an alternating electric field with at least two other electrodes. Therefore, two heating zones may be established directly next to each other, separated only by the double-use electrode itself.

[0042] Additionally or alternatively, the aerosol-forming article may comprise at least two additional electrodes or at least two additional electrode receptacles configured to receive an electrode of the aerosol-forming device when the aerosol-forming article is inserted into an aerosol-forming device for use. An additional dielectric heating zone may be formed and / or established by the at least two additional electrodes or by the at least two additional electrode receptacles. In this embodiment, the established additional heating zone may be arranged anywhere in the aerosolforming article, for example distanced from the first heating zone. It may also be provided that two pairs of electrodes form at least three heating zones, for example wherein electrodes of opposite polarity are arranged neighbouring each other on opposite sides of the respective heating zones.

[0043] In any of the described embodiments, a plurality of heating zones may be established, for example two or three or four or five or six or more than six heating zones. The heating zones may be arranged in a stacked or juxtaposed manner, such that the heating zones are all arranged in the same plane. Alternatively, the heating zones may be radially arranged with respect to each other. Other arrangements may also be possible. In the middle of the radially arranged heating zones, for example the liquid reservoir may be arranged. The heating zones may each comprise their own, separate liquid transfer element to supply the heating zones with liquid aerosol-forming substrate from the liquid reservoir. Alternatively, all the heating zones may be supplied by liquid aerosol-forming substrate by a single, common liquid transfer element. Each of the heating zones may be associated with and / or comprise and / or be arranged at a separate vapor egress surface, irrespective of whether each heating zone has its own liquid transfer element or a common liquidtransfer element is used. By establishing more than one heating zone, more aerosol may be produced per unit of time.

[0044] In case the aerosol-forming article and / or the aerosol-forming device comprises at least two heating zones, at least two of these heating zones may be separately and / or individually activated. For example, the electrodes establishing the respective heating zones may be separately and / or individually powered and / or connected to the feedback loop such that a controller may activate only one of the heating zones at a time or both heating zones simultaneously. The individually controllable heating zones may be associated with the same or different liquid transfer elements and liquid reservoirs. For example, each of the separately controllable heating zones may be associated with a separate liquid transfer element and / or a separate liquid reservoir. For example, in this way, different liquid aerosol-forming substrates may be used, each in their own liquid reservoir. These separate and different liquid aerosol-forming substrates may then be vaporized and aerosolized independently from each other, either one at a time, or simultaneously as a mixture. Different aerosols and / or aerosol mixtures may in this way be provided to the user with only one device.

[0045] In use, the aerosol-forming article is inserted into the receiving space of the aerosol-forming device. For heating in the heating zones, the electrodes of the aerosol-forming article need to be connected to the parts of the oscillator circuit arranged in the device and a power supply of the aerosol-forming device. For this purpose, the aerosol-forming article may further comprise at least two electrode connection terminals in electrical connection with the at least two electrodes. The at least two electrode connection terminals may be connectable to at least two electrode connection elements of the aerosol-forming device when the aerosol-forming article is removably inserted into or coupled to the aerosol-forming device for use. When the aerosol-forming article is inserted into the aerosol-forming device, the electrode connection terminals electrically contact the electrode connection elements so the power from the aerosol-forming device may be used for dielectric and / or resistive heating by the at least two electrodes.

[0046] For the dielectric heating, it may be preferred that the polarization of the electrodes is changed in radio frequency, e.g. an alternating RF voltage is applied across at least one pair of electrodes to cause the RF electric field. The at least two electrode connection terminals and / or the at least two electrode connection elements may be configured and / or shaped such that they have a longer extension in an insertion direction of the aerosol-forming article into the aerosolforming device than in a direction perpendicular to the insertion direction. For example, the at least two electrode connection terminals and / or the at least two electrode connection elements may be configured and / or shaped as pins, rods or cylinders. Specifically, the at least two electrode connection terminals and / or the at least two electrode connection elements may be free of pads or other shapes which might add a capacitance into the circuit with the oscillator. Keeping thecircuit, particularly the radio frequency feedback loop oscillation circuit free from parasitic capacitance increases its energy efficiency and avoids alterations of the oscillation frequency and the impedance or gain achieved by the feedback loop.

[0047] As mentioned, the at least two electrodes may form opposing electrodes of a capacitor, specifically a load capacitor, of a feedback loop of an oscillator circuit, thereby providing the dielectric heating effect in the heating zone. The feedback loop may be used to provide the oscillating current which in turn provides the oscillating electrical field in the heating zone. The feedback loop may include at least one inductor, such as a coil, a choke, or a reactor. The aerosolforming article may include the feedback loop and the at least two electrodes may be fixedly connected to the feedback loop. In this case, therefore, the feedback loop or at least part of the feedback loop comprising the at least one inductor may be part of the aerosol-forming article. Alternatively, the feedback loop may be part of the aerosol-forming device. In this case, the aerosol-forming article may be free of the feedback loop, for instance free of inductors of the feedback loop, and the at least two electrodes may be removably connectable to the feedback loop arranged in the aerosol-forming device. The more elements of the oscillation circuit may be arranged on the aerosol-forming device and not in the aerosol-forming article, the more cost-effective and environmentally sustainable the aerosol-forming article may be.

[0048] According to another aspect of the present invention, there is provided an aerosol-forming device, comprising a receiving space configured to receive the aerosol-forming article according to the present disclosure, at least two electrode connection elements configured to electrically connect to the at least two electrodes of the aerosol-forming article when the aerosol-forming article is inserted into the aerosol-forming device for use or at least two electrodes configured to enter and / or contact the at least two electrode receptacles of the aerosol-forming article when the aerosol-forming article is inserted into an aerosol-forming device for use. All of the features, effects and advantages of the aerosol-forming article according to the present disclosure are also applicable to the aerosol-forming device and vice versa.

[0049] The aerosol-forming device may comprise a protective film covering the at least two electrodes. For example, the protective film may comprise a low-dielectric material and / or may have a thickness of 0.1 mm or less. The protective film may protect the electrodes from abrasive contact with the aerosol-forming article, for example with the electrode receptacles, and may help to ensure a long lifetime of the aerosol-forming device. Also, the protective film may protect the electrodes from contact with the liquid transfer element and / or the liquid aerosol-forming substrate and / or the vapor and / or aerosol.

[0050] The aerosol-forming device may comprise an oscillator circuit electrically connected to the at least two electrode connection elements or the at least two electrodes configured to provide an alternating electrical field in the dielectric heating zone, for example an electric field alternatingdirections with a radio frequency. In other words, the oscillator circuit may be configured to drive the dielectric heating using the electrodes. Possible implementations of the oscillator circuit will be described in more detail below.

[0051] The electrodes may comprise or may be made from metal sheets, for example relatively thin metal sheets. Therefore, they may be prone to damage, for example bending out of shape, especially when an aerosol-forming article is not perfectly aligned when inserted into the aerosolforming device. To avoid damaging or bending the electrodes, it may therefore be provided that the aerosol-forming device may comprise an electrode supporting structure for supporting the at least two electrodes in the receiving space. Particularly, every electrode may be supported on an electrode supporting structure. The electrode supporting structure may be part of the housing of the aerosol-forming device and / or the receiving space. For example, the electrode supporting structure may be made from or may comprise plastic material and / or thermal insulating material. The electrode supporting structure may have a polygonal, for example a rectangular, crosssection, particularly when the electrodes are plane. Alternatively, the electrode supporting structure may have a rounded, for example oval or circular, cross-section, particularly when the electrodes are rounded. The electrode supporting structure may be complementarily shaped to the electrodes. The electrodes may be arranged and / or positioned on the outside surface of the electrode supporting structure, particularly so that the heating zone established by the electrodes is free of any part of the electrode supporting structure.

[0052] According to another aspect of the present invention, there is provided an aerosol-forming system, comprising the aerosol-forming article according to the present disclosure and an aerosol-forming device, for example the aerosol-forming device according to the present disclosure. The aerosol forming device may be configured to form or generate aerosol using the aerosol-forming article. All of the features, effects and advantages of the aerosol-forming article and / or the aerosol-forming device according to the present disclosure are also applicable to the aerosol-forming system and vice versa.

[0053] According to another aspect of the present invention, there is provided a method of heating a liquid aerosol-forming substrate in an aerosol-forming article, for example an aerosol-forming article according to the present disclosure, and / or an aerosol-forming device, for example an aerosol-forming device according to the present disclosure, comprising: establishing a dielectric heating zone by two electrodes; guiding the liquid aerosol-forming substrate from a liquid reservoir through the dielectric heating zone; and dielectric heating and vaporization of the liquid aerosolforming substrate in the dielectric heating zone; wherein an effective flow direction of liquid aerosol-forming substrate and / or vapor formed from the liquid aerosol-forming substrate through the dielectric heating zone is unidirectional, for example orthogonal to a direction of an alternating electrical field in the dielectric heating zone. All of the features, effects and advantages of theaerosol-forming article and / or the aerosol-forming device and / or the aerosol-forming system according to the present disclosure are also applicable to the method and vice versa.

[0054] The invention is defined in the claims. However, below there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0055] Example 1. An aerosol-forming article for use in an aerosol-forming device, comprising a liquid reservoir configured to store a liquid aerosol-forming substrate,

[0056] a liquid transfer element, comprising a liquid ingress surface fluidically connected to the liquid reservoir, a vapor egress surface fluidically connected to an aerosolization chamber, and a liquid transfer volume between the liquid ingress surface and the vapor egress surface configured to transfer liquid from the liquid ingress surface towards the vapor egress surface,

[0057] at least two electrodes or at least two electrode receptacles configured to form a dielectric heating zone, for example inside at least a part of the liquid transfer element, wherein the at least two electrode receptacles are each configured to receive an electrode of the aerosol-forming device when the aerosol-forming article is inserted into an aerosol-forming device for use, wherein at least a part, for example the part, of the liquid transfer element is arranged between the at least two electrodes or between the at least two electrode receptacles such that the liquid is guided from the liquid ingress surface through the dielectric heating zone, for example the dielectric heating zone caused by the at least two electrodes or the at least two electrode receptacles, towards the vapor egress surface.

[0058] Example 2. The aerosol-forming article according to Example 1,

[0059] wherein an effective flow direction of liquid aerosol-forming substrate and / or vapor formed from the liquid aerosol-forming substrate from the liquid ingress surface to the vapor egress surface is unidirectional, for example orthogonal to a direction of an alternating electrical field in the dielectric heating zone.

[0060] Example 3. The aerosol-forming article according to any one of the previous Examples, wherein an effective flow direction of vapor formed from the liquid aerosol-forming substrate through the vapor egress surface is the same as an effective flow direction of liquid aerosolforming substrate through the liquid ingress surface and / or the liquid transfer volume.

[0061] Example 4. The aerosol-forming article according to any one of the previous Examples, wherein the liquid transfer element is free of aerosol flow pathways.

[0062] Example 5. The aerosol-forming article according to any one of the previous Examples, wherein the liquid transfer element is made of or comprises one or more of

[0063] a material comprising channels or microchannels, for example a plurality of channels or microchannels, anda wicking material, for example a porous material, for example a glass-based material, for example a material comprising or primarily comprising vitreous silica or quartz glass, or a porous ceramic material, for example a porous silicon ceramic material,

[0064] for example wherein the liquid transfer element is configured to cause capillary flow of the liquid aerosol-forming substrate or wherein the liquid transfer element is configured to facilitate flow of the liquid aerosol-forming substrate by gravity.

[0065] Example 6. The aerosol-forming article according to any one of the previous Examples, wherein only a part of the liquid transfer volume is arranged in the dielectric heating zone, for example a maximum of 50% or a maximum of 40% or a maximum of 30% or a maximum of 20% or a maximum of 15% or a maximum of 10%.

[0066] Example 7. The aerosol-forming article according to any one of the previous Examples, wherein the at least two electrodes are arranged, shaped and / or configured to generate a maximal electric field amplitude at the vapor egress surface and / or in a volume of space up to 2 mm or up to 1 mm before and / or behind the vapor egress surface, for example in a direction orthogonal to a direction of an alternating electrical field in the dielectric heating zone.

[0067] Example 8. The aerosol-forming article according to any one of the previous Examples, wherein the dielectric heating zone defines a heating volume in which the liquid aerosolforming substrate is preheated and vaporized while flowing through the dielectric heating zone.

[0068] Example 9. The aerosol-forming article according to any one of the previous Examples, wherein a cross-sectional area of the liquid transfer element in the dielectric heating zone is smaller than a cross-sectional area of the liquid transfer element outside the dielectric heating zone, for example a cross-sectional area of the liquid transfer element upstream and / or downstream of the dielectric heating zone.

[0069] Example 10. The aerosol-forming article according to any one of the previous Examples, wherein a cross-sectional area of the liquid transfer element is the smallest in the dielectric heating zone.

[0070] Example 11. The aerosol-forming article according to any one of the previous Examples, wherein the liquid ingress surface is larger than the vapor egress surface and wherein the liquid transfer element is tapered towards the vapor egress surface.

[0071] Example 12. The aerosol-forming article according to any one of the previous Examples, wherein the at least two electrodes or the at least two electrode receptacles are at least partly arranged obliquely to each other such that the dielectric heating zone is tapered towards the vapor egress surface, particularly wherein a constriction and / or bottleneck is formed by the vapor egress surface.

[0072] Example 13. The aerosol-forming article according to any one of the previous Examples,wherein the at least two electrodes are configured and / or arranged with respect to each other such that the volume between the at least two electrodes forms a constriction on a side facing the vapor egress surface.

[0073] Example 14. The aerosol-forming article according to any one of the previous Examples, wherein the at least two electrodes or the at least two electrode receptacles comprise a planar or rounded surface towards the dielectric heating zone.

[0074] Example 15. The aerosol-forming article according to any one of the previous Examples, wherein the at least two electrodes or the at least two electrode receptacles are arranged such that a distance between them, particularly on a side oriented towards the vapor egress surface, is at most 2 mm or at most 1.75 mm or at most 1.5 mm or at most 1.25 mm or at most 1 mm.

[0075] Example 16. The aerosol-forming article according to any one of the previous Examples, wherein an extension of the vapor egress surface between the at least two electrodes or the at least two electrode receptacles is at most 2 mm or at most 1.75 mm or at most 1.5 mm or at most 1.25 mm or at most 1 mm.

[0076] Example 17. The aerosol-forming article according to any one of the previous Examples, further comprising an aerosolization chamber arranged in fluid connection to the vapor egress surface,

[0077] for example wherein a constriction is formed between the liquid reservoir and the aerosolization chamber, wherein the constriction is narrowest at the vapor egress surface and / or the dielectric heating zone.

[0078] Example 18. The aerosol-forming article according to any one of the previous Examples, further comprising two containment walls between the at least two electrodes or the at least two electrode receptacles, wherein the liquid transfer element is arranged between the two containment walls, for example wherein the two containment walls are part of a housing of the liquid reservoir.

[0079] Example 19. The aerosol-forming article according to the previous Example, wherein the two containment walls each have a thickness of at most 0.8 mm or at most 0.7 mm or at most 0.6 mm or at most 0.5 mm or at most 0.4 mm or at most 0.3 mm or at most 0.2 mm or at most 0.1 mm or at most 0.05 mm.

[0080] Example 20. The aerosol-forming article according to any one of the previous Examples, further comprising an outer shell, wherein the outer shell is arranged to cover at least the at least two electrodes or the at least two electrode receptacles.

[0081] Example 21. The aerosol-forming article according to any one of the previous Examples,further comprising at least one additional electrode or at least one additional electrode receptacle configured to receive an electrode of the aerosol-forming device when the aerosolforming article is inserted into an aerosol-forming device for use,

[0082] wherein at least one additional dielectric heating zone is formed by the at least one additional electrode and another electrode or by the at least one additional electrode receptacle and another electrode receptacle.

[0083] Example 22. The aerosol-forming article according to any one of the previous Examples, further comprising at least two additional electrodes or at least two additional electrode receptacles configured to receive an electrode of the aerosol-forming device when the aerosolforming article is inserted into an aerosol-forming device for use,

[0084] wherein an additional dielectric heating zone is formed by the at least two additional electrodes or by the at least two additional electrode receptacles.

[0085] Example 23. The aerosol-forming article according to any one of Examples 21-22, wherein each of the heating zones ends in a separate vapor egress surface.

[0086] Example 24. An aerosol-forming device, comprising

[0087] a receiving space configured to receive the aerosol-forming article according to any one of the previous Examples,

[0088] at least two electrode connection elements configured to electrically connect to the at least two electrodes of the aerosol-forming article when the aerosol-forming article is inserted into the aerosol-forming device for use or

[0089] at least two electrodes configured to enter the at least two electrode receptacles of the aerosol-forming article when the aerosol-forming article is inserted into an aerosol-forming device for use.

[0090] Example 25. The aerosol-forming device according to the previous Example, further comprising a protective film covering the at least two electrodes, for example wherein the protective film comprises a low-dielectric material and / or has a thickness of 0.1 mm or less.

[0091] Example 26. The aerosol-forming device according to any one of Examples 24-25, further comprising an oscillator circuit electrically connected to the at least two electrode connection elements or the at least two electrodes configured to provide an alternating electrical field in the dielectric heating zone.

[0092] Example 27. The aerosol-forming device according to any one of Examples 24-26, further comprising an electrode supporting structure for supporting the at least two electrodes in the receiving space.

[0093] Example 28. An aerosol-forming system, comprising

[0094] the aerosol-forming article according to any one of Examples 1-23, andan aerosol-forming device, for example the aerosol-forming device according to any one of Examples 24-27.

[0095] Example 29. A method of heating a liquid aerosol-forming substrate in an aerosolforming article, for example an aerosol-forming article according to any one of Examples 1-23, and / or an aerosol-forming device, for example an aerosol-forming device according to any one of Examples 24-27, and / or an aerosol-forming system, for example an aerosol-forming system according to the previous Example, comprising:

[0096] establishing a dielectric heating zone by two electrodes;

[0097] guiding the liquid aerosol-forming substrate from a liquid reservoir through the dielectric heating zone; and

[0098] dielectric heating and vaporization of the liquid aerosol-forming substrate in the dielectric heating zone;

[0099] wherein an effective flow direction of liquid aerosol-forming substrate and / or vapor formed from the liquid aerosol-forming substrate through the dielectric heating zone is unidirectional, for example orthogonal to a direction of an alternating electrical field in the dielectric heating zone.

[0100] Examples will now be further described with reference to the figures in which:

[0101] Figure 1 shows an aerosol-forming system;

[0102] Figure 2 shows a schematic illustration of an oscillation circuit for use in an aerosolgenerating system;

[0103] Figure 3a shows a schematic illustration of an oscillation circuit;

[0104] Figure 3b shows a schematic illustration of another oscillation circuit;

[0105] Figure 4 shows an oscillation circuit diagram;

[0106] Figure 5 shows an oscillation circuit comprising an inductor pair;

[0107] Figure 6 shows a longitudinal section view of an aerosol-forming article;

[0108] Figure 7 shows an aerosol-forming article in cross-section through the heating zone and the fluid transfer element;

[0109] Figure 8 shows an aerosol-forming article in cross-section through the heating zone and the fluid transfer element with rounded electrodes or electrode receptacles;

[0110] Figure 9 shows a cross-section of the receiving space of an aerosol-forming device;

[0111] Figure 10 shows a cross-section of an aerosol-forming article fitting into the receiving space as shown in Figure 9;

[0112] Figure 11 shows a cross-section of another receiving space of an aerosol-forming device; Figure 12 shows a cross-section an aerosol-forming article in the receiving space as shown in Figure 11;

[0113] Figure 13 shows another embodiment of an aerosol-forming article;

[0114] Figure 14 shows a longitudinal section view of another aerosol-forming article;Figure 15 shows a cross-section of another receiving space of an aerosol-forming device; Figure 16 shows a cross-section another aerosol-forming article;

[0115] Figure 17 shows a cross-section the aerosol-forming article of Figure 16 in the receiving space of Figure 15;

[0116] Figure 18 shows a sectional view along line C1 of Figure 15;

[0117] Figure 19 shows a sectional view along line C2 of Figure 15

[0118] Figure 20 shows a two-part system with an aerosol-forming article removably couplable to the aerosol-forming device;

[0119] Figure 21 shows a one-part system with an aerosol-forming article fixedly coupled to the aerosol-forming device; and

[0120] Figure 22 shows a flowchart of the method.

[0121] The figures are schematic only and not to scale.

[0122] Figure 1 shows an aerosol-forming or aerosol-generating system 1 for forming or generating aerosol, for example for consumption or inhalation by a user in one or more user puffs or inhalations. The system 1 may comprise at least one of cartridge holder 2, which may also be referred to as an aerosol-forming device, for generating aerosol and a companion device 3 for at least partially receiving the cartridge holder 2. The companion device 3 may be a charging device for charging the cartridge holder 2 and / or an energy storage 15 or battery thereof.

[0123] The cartridge holder 2 may comprise a receiving space or receptable chamber 29 for at least partially inserting or receiving an aerosol-forming article 18 or cartridge. The aerosol-forming article 18 may comprise a reservoir that is filled with a liquid aerosol-forming substrate, such as a nicotine containing substrate, for example a liquid that can be vaporized and thereafter aerosolized for inhalation, the article 18 being in the form of a cartridge, pod, capsule, or container. The aerosol-forming article 18 may at least partly protrude from the cartridge holder 2 when it is inserted into the cartridge holder 2, for example into the receiving space 29 of the cartridge holder 2. For example, the aerosol-forming article 18 may comprise a mouthpiece 4, through which a user may inhale aerosol provided by the cartridge holder 2 for consumption during a user puff or inhalation. The mouthpiece 4 may be a part of the aerosol-forming article 18 protruding from the cartridge holder 2. Another part of the aerosol-forming article 18 may be arranged inside the cartridge holder 2 and is therefore not visible in Figure 1. It is also possible that the aerosolforming article is fully inserted into the cartridge holder 2, with the mouthpiece 4 being part of the cartridge holder 2.

[0124] The cartridge holder 2 may further include processing circuitry or control circuitry with at least one controller 5 and one or more processors 6. For generating the aerosol during the inhalation or puff by the user, the cartridge holder 2 and article 18 may comprise a dielectric heating arrangement 7 to apply an alternating electric field to the liquid aerosol-forming substrate,to cause dielectric heating and vaporization. The processing circuitry and / or the controller 5 and / or the processor 6 may be configured to control actuation, activation and / or deactivation of the dielectric heating arrangement 7, for example using a puff sensing mechanism. Particularly, the dielectric heating arrangement 7 may comprise an oscillation circuit or at least parts of an oscillation circuit including a switching device used for dielectric heating, for example in conjunction with electrodes that are located in the aerosol-forming article 18, as explained in more detail below. The dielectric heating arrangement 7 may therefore not itself be heated, but be used to heat the liquid aerosol-forming substrate of the aerosol-forming article 18.

[0125] A puff sensor 39 may be arranged in the cartridge holder 2. The puff sensor 39 may be in fluid connection with an air flow path through the cartridge holder 2 and the aerosol-forming article 18. For example, the puff sensor 39 may be or may comprise a pressure or differential pressure sensor and may detect when the user draws or puffs on the cartridge holder 2. The detected puff may then be used by the controller 5 to activate the dielectric heating arrangement 7. Heating of the aerosol-forming substrate may therefore be implemented on-demand, for example as puff-on-demand and / or response to draw. Alternatively, heating of the aerosol-forming substrate may be implemented to be user activated by the user performing an action, for example, for example button-activated by the user pressing a button or performing some other action triggering a control signal.

[0126] For powering the at least one dielectric heating arrangement 7 with electrical power, the cartridge holder 2 may further comprise the at least one energy storage 15, for example in the form of a battery, for storing electrical energy or power. In Figure 1, both the cartridge holder 2 and the companion device 3 each comprise an energy storage 15 and the energy storage 15 is electrically coupled to the respective device 2, 3. In particular, energy storage 15 may be removably couplable to the cartridge holder 2 and / or the companion device 3. In other words, energy storage 15 may be a replaceable energy storage or battery. The connection between the energy storage 15 and the devices 2, 3 may be configured so that the devices 2, 3 may be run by electrical energy provided by the energy storage 15. Additionally, the connection between the energy storage 15 and the cartridge holder 2 and / or the companion device 3 may be configured so that data may be transmitted between the processing circuitries of the cartridge holder 2 and / or the companion device 3 and the energy storage 15.

[0127] The cartridge holder 2 may further comprise at least one electrical connector 12 for coupling to a corresponding at least one electrical connector 13 of the companion device 3 and / or an electrical connector of an external power supply (not shown), e.g., a USB charger. For example, when the cartridge holder 2 is at least partially inserted into the opening 14 of the companion device 3, the one or more electrical connectors 12 of the cartridge holder 2 may be coupled withthe one or more electrical connectors 13 of the companion device 3 to charge the at least one energy storage 15 of the cartridge holder 2.

[0128] The cartridge holder 2 may further comprise a communications arrangement 9 or communication circuitry 9 with one or more communications interfaces 10 for communicatively coupling the cartridge holder 2 with the companion device 3 or other devices, for example, via an Internet connection, a wireless LAN connection, a WiFi connection, a Bluetooth connection, a mobile phone network, a mobile data connection for example but not limited to a 3G / 4G / 5G connection, an edge connection, an LTE connection, a BUS connection, a wireless connection, a wired connection, an optical data connection such as but not limited to IrDa, a radio connection, a near field connection, and / or an loT connection.

[0129] The cartridge holder 2 may further comprise a data storage 11 or memory for storing information, program code or data. Data storage 11 may also store collected values of sensors and / or one or more mathematical functions or formulas, software and computer instructions that can be executed by the processing circuitry, particularly controller 5 and / or processor 6. One or more sensors 16 may be arranged on, at or in the cartridge holder 2 or the companion device 3 to collect data. One or more of the sensors 16 may for example be temperature sensors, strain sensors, puff sensors, accelerometers or any other suitable sensors.

[0130] The cartridge holder 2 may further comprise user interface components, for example comprising an input element or input device 8, for example in the form of a push button or a capacitive button. The input device 8 may be used as a power button to activate or deactivate the dielectric heating arrangement 7 for vaporization, thereby to activate or deactivate the cartridge holder 2. Also, a puff sensor 39 can be arranged to detect a user inhalation or puff, to active the dielectric heating arrangement 7 during the puff. Upon activation of the cartridge holder 2, the dielectric heating arrangement 7 may be activated to rapidly vaporize the liquid aerosol-forming substrate of the aerosol-forming article 18, such that vapor and aerosol can be generated for consumption or inhalation by the user. The cartridge holder 2 and / or the companion device 3 may each comprise one or more output elements, such as a display device 17 and / or one or more LEDs, for outputting a signal and / or displaying information to a user, for example a user interface such as a GUI, or haptic and acoustic data output devices. The display device 17 may be, for example, a touchscreen and may therefore be configured as both an output and an input element.

[0131] Figure 2 is a schematic illustration of an exemplary oscillation circuit 250 that can be used as or for the dielectric heating arrangement 7 for aerosol-forming system 1 or cartridge holder 2. Oscillation circuit 250 may comprise a switching unit 260 interconnected with a resonator feedback loop 270 to provide for a self-oscillating signal to the switching unit 260. The switching unit 260 may comprise a single transistor, such as a bipolar junction transistor (BJT) or a field effect transistor (FET). The oscillation circuit described herein is exemplary only, and other typesof oscillation circuits can be used, for example other types of resonant oscillator circuits where the load capacitor for causing the dielectric heating is part of the resonant feedback loop, or signal oscillators that are connected to an amplifier and an impedance matching circuit to apply an RF voltage to the electrodes for causing the alternating electric field for dielectric heating. Forced oscillators or forced oscillation circuits may also be used. The given embodiments of the oscillation circuits 250 and 355 (Figure 4) are therefore merely exemplary and not intended to limit the invention.

[0132] The oscillation circuit 250 may further comprise a choke 280 that acts on an input to the feedback loop 270 to provide for a stimulation signal, for example a stimulation voltage. The oscillation circuit may also comprise a biasing unit 290 acting on the feedback loop 270 for providing a variable or controllable biasing signal, for example a biasing voltage for setting the operating conditions. In the variant shown, the feedback signal can be described as a voltage. The output voltage UOUT of the switching unit 260 may be coupled to the feedback loop 270 providing a feedback switching signal in the form of a voltage U|Nto the switching unit 260. The configuration of the feedback loop 270 may be such that the output signal, e.g. the voltage UOUT of the switching unit 260, can undergo a phase change and arrives inverted at the input U|Nof the switching unit 260 for resonant oscillation. In other configurations, a current could be used as the feedback signal with a switching unit 260 comprising a BJT.

[0133] The feedback loop 270 may be configured to be self-oscillating and may oscillate at or close to a given resonance frequency determined by the values of the passive components of the feedback loop 270. Feedback loop 270 may be configured to provide a 180° phase shift from the output UQUT to input U|Nof switching unit 260 for oscillation, and, in addition, a transistor T (Figure 4) may be configured for inverting operation.

[0134] As shown in Figures 3a and 3b, feedback loop 270 may include a resonant circuit 272 comprising a load capacitor CLproviding for a first 90 degrees phase shift or quarter wave shift to the feedback signal. The heating zone according to the present disclosure may be arranged or may be provided inside the load capacitor CL. Feedback loop 270 may further include a capacitive element 274 providing for a second 90 degrees phase shift or quarter wave shift to the feedback signal, such that the feedback signal reaching the input of the switching unit 260 may be inverted and phase-shifted by 180 degrees. Switching unit 260 may itself be configured for inverted switching operation to provide a 180 degree phase shift between the input U|Nand the output UQUT of the switching unit 260.

[0135] Resonant circuit 272 may comprise first and second electrodes 130, 135 (which may both be referred to as electrodes 26), together forming a load capacitor CL(see Figure 4). When an aerosol-forming substrate, in the present case the liquid aerosol-forming substrate 20 that is brought into the heating zone by a liquid transfer element, is situated between the first and secondelectrodes 130, 135, it may form part of the load capacitor CL. In this non-limiting example of the oscillator, the load capacitor CLmay be formed in the feedback loop 270, and not at a separate output or part of a separate circuitry that is connected to the switching unit 260. This may enable a high-frequency oscillating voltage to be created across the electrodes 130, 135 of load capacitor CL, which is needed for sufficient and efficient dielectric heating of the aerosol-forming substrate 20, without having an additional output or circuit to the already resonating feedback loop 270. This may avoid unnecessary losses and circuit complexity. The resonant circuit 272 may comprise a series resonator circuit or a parallel resonator circuit.

[0136] Figure 4 illustrates an oscillation circuit 355 according to a non-limiting, exemplary embodiment of the present disclosure. Oscillation circuit 355 may comprise a switching unit 260 in the form of a transistor T having an intrinsic capacitance Ci. Moreover, transistor T may be configured for inverting operation, for example as an inverting common source FET, MOSFET, more specifically a LDMOS, or a common emitter BJT. The source terminal of transistor T may be coupled to a DC power supply via a choke 280. Between the gate and source terminals of transistor T a feedback loop 270 may extend. The feedback loop 270 may comprise a resonant circuit 272 including a load capacitor CLhaving a first and second electrode 130, 135 separated by an aerosol-forming substrate 20 supplied from the aerosol-forming article 18. In the variant shown, the resonant circuit 272 may also be connected to ground via a delay line DL and a capacitor C2connected in series to the delay line DL. The circuit 355 may further comprise a biasing unit 290 coupled to the gate terminal of the transistor T via the delay line DL. As shown in Figure 4, the biasing unit 290 may be electrically connected between the delay line DL and the capacitor C2, so that the biasing unit 290 may be somewhat isolated from the high oscillation frequency of the feedback loop 270.

[0137] The delay line DL may be a time delay element, for example an element that has inductive behavior, for slowing down the arriving voltage wave from the feedback loop 270 during a period of the oscillation. This may allow to tune the resonant circuit 272 to a desired switching and oscillation frequency, to move the oscillation frequency away from the natural resonant frequency given by the resonant circuit 272. This may ensure that oscillation circuit 355 remains in a predefined frequency operating range to provide for the requisite inverted or 90° phase shifted feedback and also to make sure that the feedback loop has a low impedance to provide for a high gain.

[0138] The oscillation circuit 355 is shown with electrical contacts 160, 165 that may be arranged on each side of the load capacitor CL. The first and second electrodes 130, 135 are part of the removable aerosol-forming article 18 and are therefore removable from the rest of the oscillation circuit 355. Electrical contacts 160, 165 provide a removable electrical connection between the first and second electrode 130, 135 and the feedback loop 270. As exemplarily shown in theFigure, electrical contacts 160, 165 may be arranged at different positions in the oscillator circuit 355, resulting in different components being arranged on the aerosol-forming article 18 side or the cartridge holder 2 side. For example, electrical contacts 160, 165 may be arranged between the load capacitor CL, i.e. the electrodes 26, 130, 135, and the inductors

[0139]

[0140] and L2. In this case, only the electrodes 26, 130, 135 may be arranged on and removable with the aerosol-forming article 18. As another example, the electrical contacts 160, 165 may be arranged between the inductors and L2and the load capacitor CL, i.e. the electrodes 26, 130, 135, on the one hand, and the rest of the oscillation circuit 355 on the other. In this case, the electrodes 26, 130, 135 and the inductors LT and L2may be arranged on and removable with the aerosol-forming article 18. In embodiments where the load capacitor CLis fixed within the feedback loop 270, e.g. a nonremovable cartridge as the aerosol-forming article 18, for example, electrical contacts 160, 165 provide electrical connections from the first and second electrodes to the next components in the feedback loop 270, e.g. inductors LT and L2or other components. Although two inductors LT and L2are shown, the oscillation circuit 355 may also only comprise one single inductor.

[0141] With respect to the power supply voltage, a DC power supply voltage may be provided, that is preferably in a range that is suitable for battery operation with one or more standard battery cells. Preferably, the DC power supply voltage is below 14V. For example, it is possible to operate the oscillation circuit 355 on a single battery cell, for example an 18650 battery cell (Li-Ion), or a similar battery cell, that provides for 3.2V to 3.9V. However, more preferably, a voltage of one battery cell of an exemplary 3.5V to 7V for power supply can be boosted, for example by a DC-DC converter (e.g. a boost circuit), or a voltage doubler. Alternatively or in addition, two or more battery cells can be used in series, or other configurations or arrangements that allow to increase a voltage from one or more battery cell can be used. It is also possible to have a controllable output voltage (e.g. DC-DC converter, voltage regulator), to control the temperature of heating by a change to the DC supply voltage, or to boost the voltage (for example to 10-12V) for maximum power at the preheating stage, to speed up the preheating stage with the goal to reach the aerosolization temperature quickly. Control of the DC supply voltage is one way that makes it possible to rapidly change heating power despite the oscillation circuit 355 freely oscillating.

[0142] A capacitor C-, may be arranged in parallel to the transistor T and therefore in parallel with the intrinsic capacitor of the transistor T (e.g. a field effect transistor). This may facilitate a less voltage-dependent oscillation and frequency, stabilize the oscillation, and also improve the overall dielectric heating efficiency. Capacitance of capacitor C-j may be chosen to be larger than the maximal intrinsic capacitor Ci of transistor T at the operating conditions, so that the variation of the intrinsic transistor based on frequency, temperature, etc. has much less or negligible influence on the feedback loop 270. For example, in a non-limiting embodiment, the value may be in a range between 2pF to 100pF, more preferably in a range between 5pF and 50pF.Capacitive element 274 may comprise a capacitor C2arranged at the output or end of the resonant circuit 272. In one embodiment, capacitive element 274 may comprise more than one capacitor. As described above, capacitive element 274 may have the function of providing a 90° phase shift to the feedback voltage of feedback loop 270 with minimized losses or other undesired effects, and it therefore needs to have a high-quality factor or Q factor, preferably above 1000 at 100MHz. The capacitance value for capacitor C2of the capacitive element 274 may be relatively high as compared to capacitor

[0143]

[0144] for example in a range between 500pF to 100nF, more preferably between 1 nF and 50nF, which may lead to a low impedance of capacitive element 274. In one embodiment, the capacitive element 274 may be implemented as an RC network to provide for the 90° phase shift, for example using two single-resistor-capacitor networks, having two capacitors in the feedback loop, each capacitor connected to ground via a resistor.

[0145] Resonant circuit 272, together with capacitive element 274, may provide for a 180° phase shift and a voltage gain from the output UOUT to the input U|N, and transistor T (for example a FET) may be configured for inverting operation, thereby also providing for another 180° phase shift. This may result in a resonant or close-to resonant oscillation and an amplified voltage across the electrodes 130 and 135 of the load capacitor CL, as compared to the DC supply voltage. When operating close to resonance, the resonant circuit 272 circuit may behave inductively, having a high Q factor. Furthermore, the feedback loop 270 may be impedance-matched with the transistor T, to provide for a high gain, leading to an increased voltage across the load capacitor CL.

[0146] The combination of capacitor Ci , the feedback loop with resonant circuit 272 and capacitive element 274 may also be described as a bandpass filter or Pi or TT network that generates a 180° phase shift. In the illustrated embodiment, the resonant circuit 272 of the feedback loop 270 may not be connected to ground, but may be suspended with ends at each capacitor C-, and C2, thereby not having a direct ground connection at either end of resonant circuit 272, reducing stray elements and ground influences for more predictable operation.

[0147] At the operating frequency, the resonant circuit 272 including load capacitor CLmay act as an inductive load providing a first 90° phase shift, also referred to as a quarter-wave phase shift, and capacitive element 274, which may exemplarily include a high quality factor capacitor C2 connected to ground, may provide for the second 90° phase shift or quarter-wave phase shift.

[0148] In some embodiments, oscillation circuit 355 may be based on other resonant feedback loop oscillation circuit configurations, for example, but not limited to, the use of a Colpitts or Hartley type oscillator, using an inverting transistor T. In other embodiments, the oscillator may be a forced oscillation circuit with a signal oscillator, RF amplifier, and a impedance matching network connected to the electrodes 26 for generating the alternating electric field.

[0149] Figure 5 illustrates how the electrodes 26 may protrude into the receiving space 29 of the cartridge holder 2. The receiving space 29 may be configured to removably receive the aerosol-forming article 18, wherein the electrodes 26 may be arranged to receive at least part of the aerosol-forming article 18 between them to form the heating zone 28 as explained herein. As also shown in Figure 5, the electrodes 26 may be connected to an oscillation circuit 250, 355, summarily denominated as OSC. The oscillation circuit 250, 355, may comprise two inductor coils or inductors LT and L2. The oscillation circuit 250, 355, may also comprise a magnetic core Mc, although implementations without magnetic core Mcare also possible.

[0150] Figure 6 shows a sectional view through an aerosol-forming article 18 that can be removably connected to a cartridge holder 2. The section is in the longitudinal direction, for example parallel to the insertion direction of the aerosol-forming article 18 into the cartridge holder 2. The aerosolforming article 18 may comprise an article housing 31 and an outer shell 36. The article housing 31 may form separation walls and compartments of the aerosol-forming article 18, for example for the liquid reservoir 19 and / or the aerosolization chamber 24. The outer shell 36 may form the outer contour and the outer shape or form of the aerosol-forming article 18. For example, the outer shell 36 may form a mouthpiece 4, which may, for example, have a tapered shape, and which may protrude from the cartridge holder 2 when the lower part of the aerosol-forming article 18 has been inserted into the receiving space of the cartridge holder 2. The mouthpiece 4 may be directly used by a user to inhale aerosol provided by the dielectric heating of the cartridge holder 2 and the aerosol-forming article 18.

[0151] The aerosol-forming article 18 may further comprise a liquid reservoir 19 containing a liquid aerosol-forming substrate 20, for example an e-liquid. The liquid aerosol-forming substrate 20 may be in contact with a liquid transfer element 21, which may comprise capillaries, microchannels or a porous material, or a plurality of liquid transport channels, and which may therefore transport the liquid aerosol-forming substrate 20 from a liquid ingress surface 22 through the liquid transfer volume 25 of the liquid transfer element 21 into the heating zone 28. The heating zone 28 may be established by the electrodes 26 and may comprise a volume in which the electric field is strong enough for preheating and vaporizing the liquid aerosol-forming substrate 20. The liquid transport may be achieved through capillary action by virtue of small flow pathways inside the liquid transfer element 21, or by gravity, or by a combination of both. The heating zone 28 may be a dielectric heating zone, which may be defined and / or established by a pair of electrodes and / or electrode receptacles, at least one of which may lie above or below the plane of Figure 7 and which is therefore not shown. The electrodes 26 may be connectable or couplable to parts of an oscillation circuit OSC, 250, 355 and a power supply of an cartridge holder 2 by electrode connection terminals 40. The heating zone 28 may be filled with the liquid transfer element 21 and / or may comprise an open space in fluidic connection with the aerosolization chamber 24. In the heating zone 28, for example during the transport of the liquid aerosol-forming substrate 20 through the liquid transfer element 21 , the liquid aerosol-forming substrate 20 may be heated, forexample pre-heated, and then vaporized. The vaporized substrate 20 may then exit the heating zone 28 and / or the liquid transfer element 21 through the vapor egress surface 23 of the liquid transfer element 21. The vapor egress surface 23 of the liquid transfer element 21 may be fluidically connected to, i.e. the liquid transfer element 21 may end in, the aerosol ization chamber 24, which may be part of an air flow path 34 through the cartridge holder 2. Fresh air or outside air or environmental air drawn from the outside of the cartridge holder 2, aerosol-forming article 18, or both may enter the aerosolization chamber 24 through an air inlet 32. The air may then mix with the vapor flowing from the vapor egress surface 23 and / or the heating zone 28, resulting in the formation of droplets and thereby the formation of an aerosol. By the draw or puff of the user, the aerosol may then flow through the air flow path 34 into the mouthpiece 4 to be inhaled by the user.

[0152] Figure 7 shows a cross-section through an aerosol-forming article 18, particularly through the components comprised by the article housing 31, along the line C3 of Figure 6. The Figure illustrates the flow path of the liquid aerosol-forming substrate 20 from the liquid reservoir 19 through the liquid ingress surface 22, traversing the liquid transfer volume 25 of the liquid transfer element 21 into the heating zone 28 and to the vapor egress surface 23 of the liquid transfer element 21. From there, the vapor may exit into the aerosolization chamber 24. The flow direction, particularly the effective flow direction, of the liquid aerosol-forming substrate 20 and the vapor generated or formed from this liquid from the liquid reservoir 19 to the aerosolization chamber 24 may therefore be unidirectional. The substrate and vapor may always move in the same direction, from right to left in the figure, without changing direction or effective direction. This provides for effective heating and minimum leakage, like non-vaporized liquid exiting the vapor egress surface of the fluid transfer element 21.

[0153] As shown in Figure 7, the heating zone 28 comprises a part of the liquid transfer element 21 positioned between electrodes 26 and / or electrode receptacles 27. In particular, electrodes 26 may be part of the aerosol-forming article 18. Alternatively, the electrodes 26 may be part of the cartridge holder 2, and the aerosol-forming article 18 may be free of electrodes 26. In this case, the aerosol-forming article 18 may comprise electrode receptacles 27, which may be configured to receive electrodes 26 and which may be arranged in the positions in which the electrodes 26 need to go to establish and / or define heating zone 28.

[0154] Apart from the liquid transfer element 21, at least a part of the article housing 31 may be arranged between the electrodes 26 and / or the electrode receptacles 27. Particularly, the electrodes 26 and / or the electrode receptacles 27 may be arranged on a containment wall 38 which separates the electrodes 26 and / or the electrode receptacles 27 from the liquid transfer element 21 and therefore prevents contamination of the electrodes 26 with the liquid aerosolforming substrate 20. The containment wall 38 may be especially thin and may, for example, bethinner than other parts of the article housing 31, for example in the region of the liquid reservoir 19 and / or the aerosolization chamber 24.

[0155] As can be seen in Figure 7, the electrodes 26 and / or the electrode receptacles 27 may be arranged parallel to each other, so that the heating zone 28 has a uniform thickness along the effective flow direction of the liquid aerosol-forming substrate 20 and / or the vapor. The liquid transfer element 21 may taper towards the heating zone 28. In other words, the liquid transfer element 21 may be thicker at the end of the liquid ingress surface 22 than at the heating zone 28 and / or the vapor egress surface 23. The thickness of the liquid transfer element 21 may become smaller along the effective flow direction of the liquid aerosol-forming substrate 20 and / or the vapor. This ensures sufficient flow of the liquid aerosol-forming substrate 20 into the heating zone 28 for continuous vapor and ultimately aerosol production for the user during a puff.

[0156] In an alternative embodiment, shown in Figure 8, the electrodes 26 and / or the electrode receptacles 27 may be arranged non-parallelly with regard to each other. In other words, the electrodes 26 and / or the electrode receptacles 27 may be arranged obliquely with regard to each other. Particularly, the arrangement may be such that the distance between the electrodes 26 and / or the electrode receptacles 27 may be smallest near or at the vapor egress surface 23. In this way, the strength of the alternating electrical field between the electrodes 26 is greatest in the vicinity of the vapor egress surface 23 and diminishes in the upstream direction, i.e. against the effective flow direction. The strength of the electrical field is proportional to the heating power at the respective position. Therefore, the heating power may increase along the effective flow direction through the heating zone 28 towards the vapor egress surface 23. In areas of the heating zone 28 with lesser heating power, the liquid aerosol-forming substrate 20 coming from the liquid reservoir 19 may be preheated. The actual vaporization of the liquid aerosol-forming substrate 20 may then be achieved in the area of the heating zone 28 with the most heating power, particularly in the vicinity of or at the vapor egress surface 23. Therefore, in such an embodiment, a vaporization zone 35 may be established at the downstream end of the heating zone 28 and / or the liquid transfer element 21 , i.e. at and / or directly upstream of the vapor egress surface 23. The vaporization zone 35 may be the volume of the heating zone 28 in which the highest temperatures are reached and therefore vaporization of the liquid aerosol-forming substrate 20 is achieved.

[0157] The electrodes 26 and / or the electrode receptacles 27 may be plane, for example in the form of plates and / or strips and / or pins, and / or bolts, as shown in Figure 7, or, alternatively, the electrodes 26 and / or the electrode receptacles 27 may be rounded, as shown in Figure 8. In the case of rounded electrodes 26 and / or electrode receptacles 27, the heating zone 28 may be established on the convex side of the electrodes 26 and / or electrode receptacles 27. By choosing the specific shape of the electrodes 26 and / or the electrode receptacles 27, i.e. plane or rounded, and their arrangement towards each other, i.e. parallel or oblique, the parameters of the electricfield in the heating zone 28 and therefore the parameters of heating the liquid aerosol-forming substrate 20 in the heating zone 28 may be tailored to the specific necessities of each use case. For example, different properties of different liquid substrates and / or individual preferences of users may be considered.

[0158] Figure 9 shows a cross-section through a cartridge holder 2. In particular, the receiving space 29 is shown, which is configured to receive an aerosol-forming article 18. The receiving space 29 may, for example, be part of or be provided by the housing of the cartridge holder 2. It may be shaped and / or configured as an open space corresponding to the shape and / or outer contour of the aerosol-forming article 18. Further, the cartridge holder 2 may comprise at least two electrodes 26, which may be configured to enter and / or contact the electrode receptacles 27 of the aerosol-forming article 18. Alternatively, in the case that the electrodes 26 are part of the aerosol-forming article 18, the cartridge holder 2 may comprise at least two electrode connection elements 30 or terminals, for example spring elements, which may be configured to removably electrically connect electrodes 26 of the aerosol-forming article 18 to the control circuitry and / or the power supply, i.e. the energy storage 15, of the cartridge holder 2.

[0159] Figure 10 shows an aerosol-forming article 18 complementary to the receiving space 29 of the cartridge holder 2 according to Figure 9. In contrast to the rounded aerosol-forming articles 18 shown in Figures 7 and 8, the one according to Figure 10 has an angled or polygonal outer contour. It may therefore be slotted into the angled or polygonal receiving space 29 of the cartridge holder 2 according to Figure 9.

[0160] Figure 11 shows a cross-section through another cartridge holder 2, in particular through the receiving space 29. In contrast to the previous embodiment, the cartridge holder 2 according to Figure 11 may be configured to implement more than one heating zone 28. In particular, the cartridge holder 2 may comprise more than two, in this case for example four (4), electrodes 26 and / or electrode connection elements 30. The electrodes 26 and / or electrode connection elements 30 may be stacked or juxtaposed in such a way that electrodes 26 and / or electrode connection elements 30 which are next to each other are differently charged. In this way, middle electrodes 26 may be arranged between electrodes of different charges and therefore may be used to simultaneously establish an electric field in two juxtaposed or neighboring heating zones 28. In the illustrated embodiment of Figure 11 using four electrodes 26 and / or electrode connection elements 30, a total of three heating zones 28 may be established by using the middle two electrodes 26 or electrode connection elements 34 for two neighboring heating zones 28 each.

[0161] This can also be seen in Figure 12, which shows a complementary aerosol-forming article 18 inserted into the receiving space 29 of the cartridge holder 2 according to Figure 11. Three heating zones 28 may be established by the four electrodes 26. The heating zones 28 may bearranged next to each other and may all lie in the same plane. All of the heating zones 28 may be implemented using the same liquid transfer element 21. In other words, parts of one single liquid transfer element 21 may extend into each of the heating zones 28. Each heating zone 28 may have its own vapor egress surface 23. The vapor exiting each vapor egress surface 23 may flow into a common aerosolization chamber 24 for further transport to the mouthpiece 4. Provision of multiple heating zones 28 may increase the aerosol flow or may otherwise 20 advantageously influence the quality of the aerosol, for example by adjusting the amount of vapor used for forming the aerosol per unit of time.

[0162] Figure 13 shows another exemplary embodiment of an aerosol-forming article 18 placed inside the cartridge holder 2. Specifically, an embodiment is shown in which multiple heating zones 28 may be radially arranged with respect to each other and / or with respect to a longitudinal central axis of the cartridge holder 2 and / or the aerosol-forming article 18. A liquid reservoir 19 may be arranged at least partly inside the liquid transfer element 21, for example in a center thereof. The part of the liquid reservoir 19 arranged inside the liquid transfer element 21 may be larger or bigger than any of the small flow pathways or capillaries inside the liquid transfer element 21. The liquid transfer element 21 may comprise a hollowed out space or compartment in which at least part of the liquid reservoir 19 is arranged, wherein the space or compartment is bigger than any of the pores or capillaries of the liquid transfer element 21. The heating zones 28 may be arranged radially with respect to the liquid reservoir 19. As shown in Figure 13, for example four (4) heating zones 28 may be provided at 90° to each other, but other arrangements and number of heating zones are also possible. Each of the heating zones 28 may be established by two electrodes 26 and / or electrode receptacles 27. The electrodes 26 and / or the electrode receptacles 27 may be separated for each heating zone 28. Therefore, in contrast to the previously explained embodiment, in this embodiment, no electrode 26 and / or electrode receptacle 27 may be doubly used for establishing more than one heating zone 28. Each heating zone 28 may be connected to its own, separate aerosolization chamber 24 through the respective vapor egress surface 23. Optionally, the separate heating zones 28, i.e. the electrodes establishing the heating zones 28, may be controlled separately and / or individually from each other so that the heating zones 28 may be used to heat substrate 20 separately or in combination.

[0163] As shown, the electrodes 26 may be flat but bended in a way to establish a part of the heating zone 28 with a small cross-section and a part of the heating zone 28 with a tapered crosssection, for example tapering towards the vapor egress surface 23. In this way, again, the strength of the electric field in the heating zone 28 and therefore the heating power is biggest closer to the vapor egress surface 23. Although this configuration of the electrodes 26 is shown in the embodiment of Figure 13 with separate, multiple heating zones 28, this configuration of theelectrodes 26 may also be used in other embodiments, for example having more or less, for example only one, heating zone 28.

[0164] Figure 14 shows another embodiment of an aerosol-forming article 18 in a longitudinal section. In the embodiment shown, the aerosol-forming article 18 comprises two different sections, arranged next to each other in longitudinal direction. First, the aerosol-forming article 18 comprises a mouthpiece portion comprising the mouthpiece 4. Adjacent to the mouthpiece portion, aerosol-forming article 18 comprises a neck region 33 comprising the heating zone 28. The electrodes 26 and / or electrode receptacles 27 defining the heating zone 28 may be arranged above and below the plane of the Figure and are therefore not shown. The neck region 33 has a reduced cross-section and / or diameter in relation to the mouthpiece portion. In particular, the entire aerosol-forming article 18 below the mouthpiece portion has a reduced cross-section and / or diameter in relation to the mouthpiece portion. Additionally, the heating zone 28 and therefore the electrodes 26 and / or the electrode receptacles 27 may be distanced from the mouthpiece portion by the neck region 33 by a distance d. In other words, the neck region 33 of reduced diameter in relation to the mouthpiece portion may extend from the mouthpiece portion at least for a distance d. The heating zone 28 and / or the electrodes 26 and / or the electrode receptacles 27 may be arranged a distance d away from the mouthpiece portion. The distance d may be at least 5 mm or at least 7.5 mm or at least 10 mm or at least 12.5 mm or at least 15 mm. This arrangement of the aerosol-forming article 18, and in particular the neck region 33, may allow for proper shielding of the heating zone 28 and particularly the electrodes 26, to the outside and / or other components of the cartridge holder 2.

[0165] Figure 15 shows another possible embodiment of an cartridge holder 2 and its receiving chamber 29 configured to removably receive an aerosol-forming article 18. The cartridge holder 2 comprises an electrode supporting structure 37 for each electrode 26 and / or electrode connection element 30. The electrode supporting structure 37 may, for example, be part of the housing of the cartridge holder 2 and may be made from a non-conductive material, for example a plastic or ceramic material. The electrode supporting structure 37 may be configured to physically support the electrodes 26 and / or the electrode connection elements 30 with the purpose of providing more volume and mechanical support to the electrodes 26 or electrode connection elements 30, to avoid inadvertent damaging, breaking, bending or other deformation that could happen if an object or a user touches them. Therefore, on each electrode supporting structure 37, an electrode 26 and / or an electrode connection element 30 may be arranged. The electrode 26 and / or the electrode connection element 30 may be arranged on the outside surface of the electrode supporting structure 37. The outer surface of the electrode supporting structure 37 may therefore be complementarily shaped to the shape of the electrode 26 and / or the electrode connection element 30. There may be provided one electrode supporting structure 37each for every electrode 26 and / or electrode connection element 30. Alternatively, an electrode supporting structure 37 may be used for more than one electrode 26 and / or electrode connection element 30. Moreover, in this embodiment, electrodes 26 can be arcuate or curved, and arranged such that a line arranged to form the shortest distance between the two opposing electrodes 26 coincides with a surface defined by the vapor egress surface 23. This means that the maximal amplitude or strength of the alternating electric field will also coincide or substantially coincide with the vapor egress surface 23, to focus the strongest heating energy to the vapor egress surface 23. The cartridge holder 2 may also comprise a form-fit element 45 or complementary fit element 45, which may be configured to engage, for example form-fittingly engage, a complementary element 46, for example a form-fit element 46, arranged on the aerosol-forming article 18 (see Figure 16). In this way, proper orientation of the aerosol-forming article 18 and the cartridge holder 2 may be ensured during insertion.

[0166] Figure 16 shows an aerosol-forming article 18 complementarily shaped to be removably received by the cartridge holder 2 according to Figure 15. As can be seen, the heating zone 28 is arranged at a constriction or narrow region of the article housing 31 between the liquid reservoir 19 and the aerosolization chamber 24. As already mentioned, the containment wall 38 in this region may be even thinner than the remaining walls of the article housing 31, to avoid undesired dielectric heating of these. Preferably, containment wall 38 has a thickness of at most 0.8 mm or at most 0.7 mm or at most 0.6 mm or at most 0.5 mm or at most 0.4 mm or at most 0.3 mm or at most 0.2 mm or at most 0.1 mm or at most 0.05 mm. Therefore, there may be a risk of damaging or breaking the aerosol-forming article 18 at the heating zone 28. To prevent this, the aerosolforming article 18 according to Figure 16 comprises an outer shell 36, which may be an additional housing part and which may at least partly surround the electrodes 26 and / or the electrode receptacles 27 and the heating zone 28. In the outer shell 36 may also surround or at least partly surround the liquid reservoir 19 and / or the aerosolization chamber 24 as well as parts of the air flow path 34. For example, when a user handles the aerosol-forming article 18, the user’s fingers may touch the outer shell 36, which may constitute the outer contour of the aerosol-forming article 18. In contrast, the user does not directly touch the article housing 31, for example the housing of the aerosolization chamber 24 and / or the liquid reservoir 19. In this way, the structurally weak point at the heating zone 28 is protected from damage or breaking. The outer shell 36 may also be at least partly insertable into the receiving space 29 and may even be configured to form part of the complementary shape of the aerosol-forming article 18 with regard to the receiving space 29.

[0167] Figure 17 shows the aerosol-forming article 18 of Figure 16 inserted into the receiving space 29 of the cartridge holder 2 according to Figure 15. The outer contour or shape of the outer shell 36 may help to correctly position the aerosol-forming article 18 for insertion into the receivingspace 29 without damaging the aerosol-forming article 18. A form-fitting engagement of the formfit element 45 of the cartridge holder 2 and the form-fit element 46 of the aerosol-forming article 18 may only allow insertion of the aerosol-forming article 18 in the correct alignment.

[0168] Figure 18 shows a section through the receiving space 29 of cartridge holder 2 and in particular the receiving space 29 along line C1 of Figure 15. Figure 19 offers another sectional view of the cartridge holder 2 and the receiving space 29 along line C2 of Figure 15. It can be seen that the electrode supporting structures 37 along with the electrodes 26 and / or electrode connection elements 30 may extend into the receiving space 29 against the direction of insertion of the aerosol-forming article 18.

[0169] As already mentioned, the aerosol-forming system 1 according to aspects of the disclosure may comprise a removable aerosol-forming article 18 or may comprise an aerosol-forming article 18 as a fixedly connected component of the cartridge holder 2. An aerosol-forming system 1 comprising a removable aerosol-forming article 18 is shown in Figure 20. The aerosol-forming article 18 may comprise electrodes 26, 130, 135 forming the load capacitor CL. The aerosolforming article 18 may further comprise an article part 42 of the oscillation circuit 250, 355. The cartridge holder 2 may comprise the holder part 43 of the oscillation circuit 250, 355. The holder part 43 and the article part 42 may together form the oscillation circuit 250, 355. The aerosolforming article 18 may comprise electrode connection terminals 40 for electrically connecting the electrodes 26, 130, 135 and the article part 42 to the holder part 43 via electrode connection elements 30 of the cartridge holder 2. An electrical connection between the electrode connection terminals 40 and the electrode connection elements 30 may be established when the aerosolforming article 18 is inserted into the receiving space 29 of the cartridge holder 2. The article part 42 of the oscillation circuit 250, 355 may simply comprise electrical leads connecting the electrodes 26, 130, 135 to the electrode connection terminals 40. Alternatively, the article part 42 of the oscillation circuit 250, 355 may comprise additional components of the oscillation circuit 250, 355, for example inductor LT and / or inductor L2. As also shown in Figure 20, the oscillation circuit 250, 355 may be supplied with electrical power from the energy storage 15 of the cartridge holder 2 via a DC / DC-converter 41 and the holder part 43.

[0170] An aerosol-forming system 1 comprising a fixedly connected aerosol-forming article 18 is shown in Figure 21. In contrast to the embodiment of Figure 20, the aerosol-forming article 18 may form a permanent part or component of the cartridge holder 2. Therefore, the electrodes 26, 130, 135 and the article part 42 may be permanently electrically connected to the holder part 43. The oscillation circuit 250, 355 may therefore permanently be completed. In this case, the aerosolforming system 1 may comprise a refillable reservoir 44 for liquid aerosol-forming substrate 20. A user may therefore refill the refillable reservoir 44 whenever the liquid aerosol-forming substrate 20 is depleted or partially depleted.Figure 22 shows a flowchart of the method 60 of heating a liquid aerosol-forming substrate 20 in an aerosol-forming article 18 and / or an cartridge holder 2. In case that the aerosol-forming article 18 is a removable cartridge, the method 60 may begin with the insertion or inserting the aerosol-forming article 18 into the receiving space 29 of the cartridge holder 2. At least a part of the aerosol-forming article 18 may be inserted into an area where the heating zone 28 will be established during this insertion. After the insertion, the method 60 may continue in step 61 by establishing a dielectric heating zone 28 by two electrodes 26. In case that the aerosol-forming article 18 is fixedly connected to the cartridge holder 2, the method 60 may begin in step 61 by establishing a dielectric heating zone 28 by two electrodes 26. For this purpose, an oscillator circuit 250, 355 as explained herein may be used. In step 62, liquid aerosol-forming substrate 20 from a liquid reservoir 19 may be guided through the dielectric heating zone 28, for example by capillary action achieved in a liquid transfer element 21. The liquid may be guided through the liquid transfer element 21 and particularly through the heating zone 28 unidirectionally, as explained herein. This may mean that an effective flow direction of the liquid aerosol-forming substrate 20 and / or vapor formed from the liquid aerosol-forming substrate 20 through the dielectric heating zone 28 is unidirectional, for example orthogonal to a direction of an alternating electrical field in the dielectric heating zone 28. Method 60 may further comprise step 63 of dielectric heating and vaporization of the liquid aerosol-forming substrate 20 in the dielectric heating zone 28. The vapor may then be mixed with outside or environmental air to generate, produce or form an aerosol for consumption by a user by inhalation. All of the other features of the present disclosure as explained herein are also applicable to the method 60 and are not repeated.

[0171] In summary, the present disclosure provides for an aerosol-forming article 18, a cartridge holder 2 for the aerosol-forming article 18, and an aerosol-forming system 1 using dielectric heating with high efficiency with reduced losses, and proposing a solution to minimize volumetric heating of the liquid aerosol-forming substrate. Using the invention, a reliable flow of high quality aerosol during each puff of the user can be ensured while simultaneously, the lifetime of the energy supply, for example the battery, of the cartridge holder 2 is increased.

[0172] The terms “upstream” and “downstream” as used in the present disclosure may pertain to a flow direction, for example the effective flow direction, of the liquid aerosol-forming substrate from the liquid reservoir to the aerosolization chamber, for example inside the liquid transfer element. An element arranged upstream of another element is located closer to the liquid reservoir and / or the liquid ingress surface than the other element. In turn, an element arranged downstream of another element is located closer to the aerosolization chamber and / or the vapor egress surface than the other element. These terms therefore signify the relative positioning ofthe respective elements along the flow direction, for example the effective flow direction, of the liquid aerosol-forming substrate from the liquid reservoir to the aerosolization chamber.

[0173] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ±10 % of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

42 / 46CLAIMS1. An aerosol-forming article for use in an aerosol-forming device, comprisinga liquid reservoir configured to store a liquid aerosol-forming substrate,a liquid transfer element, comprising a liquid ingress surface fluidically connected to the liquid reservoir, a vapor egress surface fluidically connected to an aerosolization chamber, and a liquid transfer volume between the liquid ingress surface and the vapor egress surface configured to transfer liquid from the liquid ingress surface towards the vapor egress surface,at least two electrodes or at least two electrode receptacles configured to form a dielectric heating zone inside at least a part of the liquid transfer element, wherein the at least two electrode receptacles are each configured to receive an electrode of the aerosol-forming device when the aerosol-forming article is inserted into an aerosol-forming device for use,wherein at least the part of the liquid transfer element is arranged between the at least two electrodes or between the at least two electrode receptacles such that the liquid is guided from the liquid ingress surface through the dielectric heating zone caused by the at least two electrodes or the at least two electrode receptacles towards the vapor egress surface.

2. The aerosol-forming article according to claim 1 ,wherein an effective flow direction of liquid aerosol-forming substrate and / or vapor formed from the liquid aerosol-forming substrate from the liquid ingress surface to the vapor egress surface is unidirectional, for example orthogonal to a direction of an alternating electrical field in the dielectric heating zone.

3. The aerosol-forming article according to any one of the previous claims,wherein the liquid transfer element is free of aerosol flow pathways, and / orwherein only a part of the liquid transfer volume is arranged in the dielectric heating zone, for example a maximum of 50% or a maximum of 40% or a maximum of 30% or a maximum of 20% or a maximum of 15% or a maximum of 10%.

4. The aerosol-forming article according to any one of the previous claims,wherein the at least two electrodes are arranged, shaped and / or configured to generate a maximal electric field amplitude at the vapor egress surface and / or in a volume of space up to 2 mm or up to 1 mm before and / or behind the vapor egress surface, for example in a direction orthogonal to a direction of an alternating electrical field in the dielectric heating zone.

5. The aerosol-forming article according to any one of the previous claims,43 / 46wherein a cross-sectional area of the liquid transfer element in the dielectric heating zone is smaller than a cross-sectional area of the liquid transfer element outside the dielectric heating zone, for example a cross-sectional area of the liquid transfer element upstream and / or downstream of the dielectric heating zone,and / or wherein a cross-sectional area of the liquid transfer element is the smallest in the dielectric heating zone.

6. The aerosol-forming article according to any one of the previous claims,wherein the at least two electrodes or the at least two electrode receptacles are at least partly arranged obliquely to each other such that the dielectric heating zone is tapered towards the vapor egress surface, particularly wherein a constriction and / or bottleneck is formed by the vapor egress surface.

7. The aerosol-forming article according to any one of the previous claims,wherein the at least two electrodes are configured and / or arranged with respect to each other such that the volume between the at least two electrodes forms a constriction on a side facing the vapor egress surface.

8. The aerosol-forming article according to any one of the previous claims,wherein the at least two electrodes or the at least two electrode receptacles are arranged such that a distance between them, particularly on a side oriented towards the vapor egress surface, is at most 2 mm or at most 1.75 mm or at most 1.5 mm or at most 1.25 mm or at most 1 mm.

9. The aerosol-forming article according to any one of the previous claims,further comprising an aerosolization chamber arranged in fluid connection to the vapor egress surface,for example wherein a constriction is formed between the liquid reservoir and the aerosolization chamber, wherein the constriction is narrowest at the vapor egress surface and / or the dielectric heating zone.

10. The aerosol-forming article according to any one of the previous claims,further comprising two containment walls between the at least two electrodes or the at least two electrode receptacles, wherein the liquid transfer element is arranged between the two containment walls,44 / 46for example wherein the two containment walls are part of a housing of the liquid reservoir, and / or wherein the two containment walls each have a thickness of at most 0.8 mm or at most 0.7 mm or at most 0.6 mm or at most 0.5 mm or at most 0.4 mm or at most 0.3 mm or at most 0.2 mm or at most 0.1 mm or at most 0.05 mm.

11. The aerosol-forming article according to any one of the previous claims,further comprising an outer shell, wherein the outer shell is arranged to cover at least the at least two electrodes or the at least two electrode receptacles.

12. The aerosol-forming article according to any one of the previous claims,further comprising at least one additional electrode or at least one additional electrode receptacle configured to receive an electrode of the aerosol-forming device when the aerosolforming article is inserted into an aerosol-forming device for use,wherein at least one additional dielectric heating zone is formed by the at least one additional electrode and another electrode or by the at least one additional electrode receptacle and another electrode receptacle.

13. An aerosol-forming device, comprisinga receiving space configured to receive the aerosol-forming article according to any one of the previous claims,at least two electrode connection elements configured to electrically connect to the at least two electrodes of the aerosol-forming article when the aerosol-forming article is inserted into the aerosol-forming device for use orat least two electrodes configured to enter the at least two electrode receptacles of the aerosol-forming article when the aerosol-forming article is inserted into an aerosol-forming device for use.

14. An aerosol-forming system, comprisingthe aerosol-forming article according to any one of claims 1-12, andan aerosol-forming device, for example the aerosol-forming device according to the previous claim.

15. A method of heating a liquid aerosol-forming substrate in an aerosol-forming article, for example an aerosol-forming article according to anyone of claims 1-12, and / or an aerosol-forming device, for example an aerosol-forming device according to claim 13, and / or an aerosol-forming system, for example an aerosol-forming system according to the previous claim, comprising:establishing a dielectric heating zone by two electrodes;guiding the liquid aerosol-forming substrate from a liquid reservoir through the dielectric heating zone; anddielectric heating and vaporization of the liquid aerosol-forming substrate in the dielectric heating zone;wherein an effective flow direction of liquid aerosol-forming substrate and / or vapor formed from the liquid aerosol-forming substrate through the dielectric heating zone is unidirectional, for example orthogonal to a direction of an alternating electrical field in the dielectric heating zone.

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