An aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming substrate

Abstract

The present disclosure relates to an aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming substrate. The device comprises a device housing comprising a cavity configured to removably receive an aerosol-forming substrate to be heated. The device further comprises an induction heating device comprising at least one induction coil for generating a varying magnetic field within the cavity, wherein the induction coil is arranged around at least a portion of the receiving cavity. In addition, the device comprises a flux concentrator arranged around at least a portion of the induction coil and configured to distort the varying magnetic field of the at least one induction heating device towards the cavity during use of the device. The flux concentrator comprises a multi-layer flux concentrator foil having at least one magnetic layer laminated with at least a first support layer, wherein the magnetic layer comprises a plurality of separate flakes of a soft magnetic alloy. The present disclosure also relates to an aerosol-generating system comprising such a device and an aerosol-generating article, wherein the article comprises an aerosol-forming substrate to be heated. Moreover, the present disclosure relates to a method for manufacturing a multi-layer flux concentrator foil for such a device.

Description

[0001] This disclosure relates to an aerosol generating apparatus for generating aerosols by induction heating of an aerosol forming matrix, wherein the apparatus includes a flux concentrator foil. This disclosure also relates to an aerosol generating system including such an apparatus and an aerosol generating article, wherein the article includes an aerosol forming matrix to be heated. Furthermore, this disclosure relates to a method for manufacturing a multilayer flux concentrator foil for such an apparatus.

[0002] Aerosol generation systems for induction heating of an aerosol-forming matrix capable of forming inhalable aerosols are generally known in the prior art. Such systems may include an aerosol generation apparatus having a cavity for receiving a matrix to be heated. The matrix may be an integral part of an aerosol-generating article configured for use with the apparatus. To heat the matrix, the apparatus may include an induction heating device comprising an induction coil for generating a changing magnetic field within the cavity. This field is used to induce at least one of eddy currents or hysteresis losses in a sensor, which is arranged in thermal proximity or direct physical contact with the matrix during system use for heating. Typically, the sensor may be an integral part of the apparatus or an integral part of the article.

[0003] Magnetic fields can not only induce heating sensors but also interfere with other sensitive components of the aerosol generating device or sensitive external objects adjacent to the device. To reduce such undesirable interference, the aerosol generating device may be equipped with a flux concentrator arranged around the induction heating element, which is generally used to confine the magnetic field generated by the heating element essentially within the volume enclosed by the flux concentrator. However, it has been observed that when the device is subjected to excessive impact or vibration, such as after an accidental drop, the confinement effect usually diminishes or even disappears. In addition, many flux concentrators are quite large, thus significantly increasing the overall mass and size of the aerosol generating device. Moreover, it has been observed that the flux concentrator itself undesirably heats up during device use, particularly when the device is operated with a varying magnetic field in the megahertz range.

[0004] Therefore, there is a need for an aerosol generation apparatus and system for induction heating aerosol forming matrix that combines the advantages of existing technological solutions while mitigating their limitations. In particular, there is a need for an aerosol generation apparatus and system that includes a flux concentrator with enhanced robustness and a compact design, yet generates less heat during device use.

[0005] According to one aspect of the invention, an aerosol generating apparatus is provided for generating an aerosol by inductively heating an aerosol forming matrix. The apparatus includes an apparatus housing comprising a cavity configured to removably receive an aerosol forming matrix to be heated. The apparatus also includes an induction heating device comprising at least one induction coil for generating a varying magnetic field within the cavity, wherein the induction coil is arranged around at least a portion of the receiving cavity. Additionally, the apparatus includes a flux concentrator arranged around at least a portion of the induction coil and configured to distort the varying magnetic field of the at least one induction heating device toward the cavity during use of the apparatus. The flux concentrator comprises a multilayer flux concentrator foil having at least one magnetic layer laminated with at least a first support layer, wherein the magnetic layer comprises a plurality of separated fragments of a soft magnetic alloy.

[0006] According to the present invention, flux concentrators comprising or made of flux concentrator foil have been found to be more flexible than other flux concentrator constructions (e.g., solid ferrite bodies). For this reason, flux concentrator foil provides excellent damping characteristics and can therefore withstand higher excessive impacts or vibrations without breaking. For example, compared to sensors made of sintered ferrite powder, flexible flux concentrator foil provides substantially improved resistance to impact loads such as those caused by accidental drops. Furthermore, due to its smaller size, flux concentrator foil allows for more compact designs of aerosol generating devices. In particular, flux concentrator foil can be made significantly thinner compared to sintered ferrite flux concentrators. Moreover, compared to solid flux concentrators, flux concentrator foil also allows for compensation of manufacturing tolerances and fine-tuning of inductance. In particular, flux concentrator foil can advantageously help enhance the impedance stability of the induction coil with temperature. Generally, the impedance of the induction coil is affected by the presence of a flux concentrator. When using flux concentrator foil, the conductivity of the induction heating system may change less with temperature due to the small size of the foil, especially compared to large-volume solid flux concentrators. Therefore, the impedance may also change less with temperature. Furthermore, flux concentrator foil is easy to manufacture.

[0007] Most importantly, because the magnetic layer comprises multiple separate fragments, the formation of eddy currents within the magnetic layer is partially suppressed because each individual fragment provides only a limited space for eddy current formation. That is, the fragmented magnetic layer has a reduced AC resistance compared to the non-fragmented magnetic layer. As a result, there is no or only minimal energy dissipation in the fragments, causing the flux concentrator foil as a whole to heat up only slightly (if any). Therefore, the vast majority of the energy provided by the changing magnetic field can be dissipated in the sensor and thus effectively used for the aerosol-forming matrix in the heating chamber.

[0008] As used in this article, the term "concentrated magnetic field" refers to the ability of a flux concentrator to distort the magnetic field, thereby increasing the magnetic field density within the cavity.

[0009] By distorting the magnetic field toward the cavity, the flux concentrator reduces the extent to which the magnetic field propagates outside the induction coil. In other words, the flux concentrator acts as a magnetic shield. This reduces unwanted heating of adjacent sensitive components of the device (e.g., the metal casing) or adjacent sensitive objects outside the device. By reducing unwanted heat loss, the efficiency of the aerosol generating device can be further improved.

[0010] Furthermore, by twisting the magnetic field toward the cavity, the flux concentrator can advantageously concentrate or focus the magnetic field within the cavity. Compared to an induction coil without a flux concentrator, this increases the level of heat generated in the sensor for a given power level passing through the induction coil. Therefore, the efficiency of the aerosol generating device can be improved.

[0011] As used herein, the term "foil" refers to a thin sheet material whose thickness is much smaller than its dimension in any direction perpendicular to the thickness. As used herein, the term "thickness" refers to the dimension of the foil perpendicular to its principal surface. The thickness of the flux concentrator foil can be between 0.02 mm and 0.25 mm, particularly between 0.05 mm and 0.2 mm, and preferably between 0.1 mm and 0.15 mm. For example, the flux concentrator foil can have a thickness of 62 micrometers. The thickness of the flux concentrator foil can be up to 150 micrometers, particularly up to 100 micrometers, and preferably up to 80 micrometers. Such values ​​of thickness allow for a particularly compact design of the aerosol generating apparatus. However, these values ​​are still large enough to sufficiently distort the alternating magnetic field of the induction heating device toward the cavity during use of the apparatus.

[0012] The thickness of a flux concentrator can be substantially constant along any direction perpendicular to its thickness. In other instances, the thickness of the flux concentrator can vary along one or more directions perpendicular to its thickness. For example, the thickness of the flux concentrator can taper or decrease from one end to the other or from the center of the flux concentrator toward both ends. The thickness of the flux concentrator can be substantially constant around its circumference. In other instances, the thickness of the flux concentrator can vary around its circumference.

[0013] The thickness of the magnetic layer can be between 15 micrometers and 100 micrometers, particularly in the range of 18 micrometers and 40 micrometers, for example, 20 millimeters. The thickness of the magnetic layer can be up to 100 micrometers, particularly up to 50 micrometers, preferably up to 40 micrometers. The thickness of the magnetic layer can be up to 75% of the thickness of the flux concentrator foil, particularly 50%, more particularly at least 40%, preferably at least 35%.

[0014] Advantageously, the first support layer is used to bond and support debris laminated with the first support layer. Preferably, the multilayer flux concentrator foil may also include a second support layer opposite to the first support layer on one side of at least one magnetic layer or (as further described below) on one side of a plurality of adjacent magnetic layers. Like the first support layer, the second support layer is preferably laminated with at least one magnetic layer or (if applicable) with a plurality of adjacent magnetic layers. Advantageously, the second layer is also used to bond and support debris.

[0015] At least the first support layer and (if present) the substrate layer of the second support layer may comprise a polymer film. The polymer film may be selected from polyester, polyimide, polyol, or combinations thereof. The substrate layer may comprise a release liner. Preferably, at least one of the first support layer and (if present) the second support layer may be an adhesive layer, an electrically insulating layer, or an electrically insulating adhesive layer. Using an electrically insulating adhesive layer advantageously avoids short circuits of debris within at least one magnetic layer, or (if applicable) avoids short circuits of debris within a plurality of adjacent magnetic layers respectively adjacent to the first or second support layer.

[0016] The first support layer and (if present) the second support layer may be the edge layer of the multilayer flux concentrator foil, that is, one of the two outermost layers of the multilayer flux concentrator foil.

[0017] As used herein, the term "magnetism" refers to either ferromagnetism or ferrimagnetism. That is, soft magnetic alloys are either ferromagnetic or ferrimagnetic.

[0018] As used herein, the term soft magnetic alloy refers to a magnetic alloy having low magnetic coercivity, particularly at most 100 A / m, preferably at most 50 A / m, more preferably at most 10 A / m, and most preferably at most 5 A / m. Magnetic coercivity is a measure of the ability of a magnetic material to withstand an external magnetic field without becoming demagnetized. Due to its low magnetic coercivity, soft magnetic alloys advantageously exhibit low hysteresis losses.

[0019] Preferably, the soft magnetic alloy is brittle. This proves advantageous in breaking the soft magnetic alloy into multiple separate fragments.

[0020] The soft magnetic alloy of the flux concentrator foil may include any material or combination of materials suitable for distorting the magnetic field, or may be made of any material or combination of materials suitable for distorting the magnetic field.

[0021] Preferably, the soft magnetic alloy can be a metallic glass (amorphous metal) or a nanocrystalline soft magnetic alloy, particularly a nanocrystalline soft magnetic iron-based alloy.

[0022] In particular, the soft magnetic alloy of the flux concentrator foil may be or may include Fe. 100-a-b-c-x-y-zCu a M b T c Si x Z z and a composition with up to 0.5 atomic % of contaminants, where M is one or more of Nb, Mo, and Ta, T is one or more of V, Cr, Co, and Ni, and Z is one or more of C, P, and Ge, and where 0.5 atomic % < a < 1.5 atomic %, 2 atomic % ≤ b < 4 atomic %, 0 atomic % ≤ c < 5 atomic %, 12 atomic % < x < 18 atomic %, 5 atomic % < y < 12 atomic %, and 0 atomic % ≤ z < 2 atomic %.

[0023] For example, the soft magnetic alloy of the flux concentrator foil may include, or may be made of, an alloy sold by VACUUMSCHMELZE GmbH & Co. KG under the trademark or may be made therefrom. The alloy is a nanocrystalline soft magnetic alloy. For example, the flux concentrator foil may include Vitroperm 220, Vitroperm 250, Vitroperm 270, Vitroperm 400, Vitroperm 500, or Vitroperm 800, or may be made of these. In particular, the soft magnetic alloy may be or may include Fe 73.8 Nb3Cu1Si 15.6 B 6.6 composition. This composition corresponds to Vitroperm 800.

[0024] As used herein, the term "flux concentrator" refers to a component having a high relative magnetic permeability, which is used to concentrate and guide the magnetic field or magnetic field lines generated by an induction coil. As used herein, the term "high relative magnetic permeability" means a relative magnetic permeability of at least 10, particularly at least 1000, preferably at least 10000, even more preferably at least 50000, and most preferably at least 80000. These exemplary values refer to the maximum relative magnetic permeability for frequencies up to 50 kHz and a temperature of 25 degrees Celsius. The term "relative magnetic permeability" refers to the ratio of the magnetic permeability of a material or medium (such as a flux concentrator) to the magnetic permeability μ_0 of free space, where μ_0 is 4π·10 -7 N·A -2 (4·Pi·10E - 07 newtons per square ampere). Thus, the relative magnetic permeability of the soft magnetic alloy is preferably at least 100, particularly at least 1000, preferably at least 10000, even more preferably at least 50000, and most preferably at least 80000. These values preferably refer to the maximum relative magnetic permeability at frequencies up to 50 kHz and a temperature of 25 degrees Celsius.

[0025] As will be described in further detail below with respect to the method of the present invention, the fragmented magnetic layer can be generated by a multilayer flux concentrator foil having at least one magnetic layer of a soft magnetic alloy laminated with at least a first support layer, wherein the magnetic layer fragments into multiple separate fragments. For example, the fragmentation of the magnetic layer can be achieved by applying an external force transversely to the plane of the foil to the flux concentrator foil. Although the magnetic layer fragments into multiple fragments, the first support layer and (if present) the second support layer remain intact and do not fragment, so as to hold the fragmented magnetic layer together.

[0026] Depending on the tools and methods used to break the magnetic layer into fragments, multiple fragments can be arranged in a pattern comprising multiple crack centers, wherein multiple cracks extend radially outward from each crack center in a mesh pattern.

[0027] Depending on the tools and methods used, fragments can have different types of shapes. For example, fragments can have a sheet-like shape.

[0028] Preferably, the size of each individual fragment can be at most 1 millimeter, particularly at most 750 micrometers or at most 500 micrometers. Similarly, the average fragment size of multiple separated fragments can be at most 1 millimeter, particularly at most 750 micrometers or at most 500 micrometers. Such values ​​of fragment size allow for a further reduction in the AC resistance of the magnetic layer, and thus allow for a further reduction in eddy current losses in the flux concentrator foil.

[0029] Generally, a multi-layer flux concentrator foil may comprise a single magnetic layer. A multi-layer flux concentrator foil may also comprise multiple adjacent magnetic layers. Multiple adjacent magnetic layers enhance the flux concentration effect. Furthermore, using a foil with multiple adjacent magnetic layers reduces the workload of arranging the flux concentrator foil around the induction coil, because a single winding of a multi-layer flux concentrator foil can achieve the same effect as a single-layer flux concentrator foil arranged with multiple windings stacked on top of each other around the induction coil.

[0030] Regarding flux concentrator foils having multiple adjacent magnetic layers, multilayer flux concentrator foils may include an adhesive film, particularly an electrically insulating adhesive film, disposed between each pair of adjacent magnetic layers. Advantageously, the adhesive film is used to bond and support multiple fragments of each magnetic layer. Using an electrically insulating adhesive film avoids short-circuiting of fragments within one magnetic layer or multiple adjacent layers via the adhesive film. The adhesive film disposed between each pair of adjacent magnetic layers may also be represented as an intermediate support layer. That is, the flux concentrator foil may also include at least one intermediate support layer. The intermediate support layer may be disposed between a pair of adjacent magnetic layers. Further details will be further described below with respect to the method according to the invention, and equally applicable to the aerosol generating apparatus according to the invention as described herein.

[0031] For example, a multilayer flux concentrator foil may include the following layers (from bottom to top):

[0032] - Adhesive (non-PET) first support layer,

[0033] - A first magnetic layer, the first magnetic layer comprising or made of a soft magnetic alloy.

[0034] - Adhesive (non-PET) intermediate support layer

[0035] - A second magnetic layer, the second magnetic layer comprising or made of a soft magnetic alloy, and

[0036] - Adhesive (PET-based) second support layer.

[0037] As will be described in more detail below, a multi-layer flux concentrator foil can be a sealed multi-layer flux concentrator foil. That is, the multi-layer flux concentrator foil can be sealed to prevent debris from laterally escaping from the foil. For this purpose, a sealing adhesive tape can be disposed on one or both sides of the (unsealed) flux concentrator foil, wherein the adhesive sealing tape has a width extension in a direction transverse to the opposite (cut) edges of the flux concentrator foil, said width extension being greater than the width extension of the unsealed flux concentrator foil in the same direction (that is, in a direction transverse to the opposite cut edges of the (unsealed) flux concentrator foil). As a result, the sealing adhesive tape on each side of the (unsealed) flux concentrator foil includes laterally projecting wings that can make adhesive contact with each other to seal the edges of the (unsealed) flux concentrator. For example, a sealed multi-layer flux concentrator foil may include the following layers (from bottom to top):

[0038] - A first three-layer adhesive sealing laminate, comprising a (PEN-based or PI-based) film sandwiched between a first adhesive layer and a second adhesive layer.

[0039] - Adhesive (non-PET) first support layer,

[0040] - A first magnetic layer, the first magnetic layer comprising or made of a soft magnetic alloy.

[0041] - Adhesive (non-PET) intermediate support layer

[0042] - A second magnetic layer, the second magnetic layer comprising or made of a soft magnetic alloy.

[0043] - Adhesive (PET-based) second support layer, and

[0044] - A second or third adhesive sealing laminate, comprising a (PEN-based or PI-based) membrane sandwiched between a first adhesive layer and a second adhesive layer.

[0045] As another example, a sealed multilayer flux concentrator foil may include the following layers (from bottom to top):

[0046] -The first PET-based adhesive film,

[0047] - Adhesive (non-PET) first support layer,

[0048] - A first magnetic layer, the first magnetic layer comprising or made of a soft magnetic alloy.

[0049] - Adhesive (non-PET) intermediate support layer

[0050] - A second magnetic layer, the second magnetic layer comprising or made of a soft magnetic alloy.

[0051] - Adhesive (PET-based) second support layer, and

[0052] - Second PET-based adhesive film.

[0053] The first and second three-layer adhesive sealing laminates may include a PEN (polyethylene terephthalate)-based film sandwiched between the first and second adhesive layers. Similarly, the three-layer adhesive sealing laminate may include a PI (polyimide)-based film sandwiched between the first and second adhesive layers. The thickness of the PEN (polyethylene terephthalate)-based film may be 2-5 micrometers, particularly 3 micrometers. Likewise, the thickness of the PI (polyimide)-based film may be 2-8 micrometers, particularly 5-7 micrometers. In general, the thickness of the three-layer adhesive sealing laminate may be 3-15 micrometers, particularly 4-13 micrometers, for example 5 micrometers, or 7 micrometers, or 9 micrometers, or 13 micrometers. The first and second adhesive layers of the three-layer sealing adhesive tape may include an adhesive not based on PET (polyethylene terephthalate).

[0054] The first and second PET-based adhesive films may have a thickness of 2-5 micrometers, particularly 3 micrometers.

[0055] The thickness of the first and second support layers of the adhesive (non-PET based) and the third support layer of the adhesive (PET based) can be in the range of 2 micrometers to 10 micrometers, particularly in the range of 2 micrometers to 5 micrometers, for example 3 micrometers.

[0056] The thickness of the first magnetic layer and the second magnetic layer can be in the range of 15 micrometers to 25 micrometers, especially in the range of 18 micrometers to 23 micrometers, for example 21 micrometers.

[0057] Further details of the various strips, films, and layers will be described below with respect to the method according to the invention, and equally applicable to the aerosol generating apparatus according to the invention as described herein.

[0058] As used herein, the term "separated fragments" refers to the construction of a magnetic layer comprising multiple fragments or clusters of fragments that are not in indirect contact, and in particular not in electrical contact with adjacent fragments or clusters of fragments, in order to allow suppression of eddy current effects.

[0059] The gaps between multiple separated fragments or clusters of fragments may be at least partially filled with an electrically insulating material, such as an adhesive, for example, a polymer such as silicone. Specifically, the gaps between multiple separated fragments or clusters of fragments may be at least partially filled with at least one of the material of a first support layer, or (if present) the material of a second support layer, or (if present) the material of an adhesive film between adjacent magnetic layers, or filled with a matrix material of a soft magnetic alloy (adhesive). Filling the gaps advantageously helps to permanently separate the multiple fragments or clusters of fragments from each other, and thus keeps eddy current effects permanently suppressed, even when the flux concentrator foil deforms as a whole.

[0060] Additionally, the aerosol generating device may include a radial gap between at least one induction coil and a flux concentrator, which at least partially surrounds the induction coil. Therefore, the gap also at least partially surrounds the induction coil. The gap may have a radial extension between 40 micrometers and 400 micrometers, particularly between 100 micrometers and 240 micrometers, for example, 220 micrometers. Advantageously, the gap can help reduce losses in the induction coil and increase losses in the sensor to be heated, that is, increase the heating efficiency of the aerosol generating device.

[0061] The gap may be an air gap or a gap at least partially filled with a filler material, such as polyimide, for example poly(4,4'-oxophenylene-pyromellitic tetracarboxylate), also known as... Or any other suitable dielectric material. Specifically, the first dielectric package may be arranged around at least a portion of the induction coil between the induction coil and the flux concentrator. For example, the induction coil may be wrapped with one or more layers of Kapton tape to fill at least one radial gap between the induction coil and the flux concentrator. A single layer of Kapton tape may have a thickness in the range of 40 micrometers to 80 micrometers.

[0062] Furthermore, the aerosol generating apparatus may include conductive shielding packaging arranged around the flux concentrator. Advantageously, the conductive shielding packaging serves to protect the environment of the apparatus from the influence of magnetic fields within the apparatus.

[0063] Additionally, the aerosol generating apparatus may include a second dielectric package arranged around the flux concentrator, and particularly (if present) around the shielding package. Like the first dielectric package, the second dielectric package can help reduce losses in the induction coil and increase losses in the sensor to be heated, that is, increase the heating efficiency of the aerosol generating apparatus.

[0064] Generally, flux concentrators can have any shape, but preferably have a shape that matches the shape of at least one inductor, the flux concentrator being arranged at least partially around the at least one inductor.

[0065] For example, the flux concentrator can have a substantially cylindrical shape, particularly a sleeve shape or a tubular shape. That is, the flux concentrator can be a tubular flux concentrator, a flux concentrator sleeve, or a cylindrical flux concentrator. Such shapes are particularly suitable when at least one induction coil is a helical induction coil with a substantially cylindrical shape. In such configurations, at least a portion of the flux concentrator extending along the axial length of the coil completely defines at least one induction coil. Tubular or sleeve shapes have proven particularly advantageous with respect to the cylindrical shape of the cavity and to the cylindrical and / or helical configuration of the induction coil. For this shape, the flux concentrator can have any suitable cross-section. For example, the flux concentrator can have a square, elliptical, rectangular, triangular, pentagonal, hexagonal, or similar cross-sectional shape. Preferably, the flux concentrator has a circular cross-section. For example, the flux concentrator can have a circular or cylindrical shape.

[0066] The flux concentrator may also extend only around a portion of the circumference of at least one induction coil.

[0067] In any of these configurations, the flux concentrator is preferably arranged coaxially with the centerline of at least one induction coil. Even more preferably, the flux concentrator and at least one induction coil are coaxial with the centerline of the cavity.

[0068] Generally, an induction heating device may include a single induction coil or multiple induction coils, particularly two induction coils. In the case of a single induction coil, the flux concentrator may be arranged around at least a portion of the single induction coil, preferably entirely around the induction coil. In the case of multiple induction coils, the flux concentrator may be arranged around at least a portion of one of the induction coils, preferably around at least a portion of each of the induction coils, and even more preferably entirely around each induction coil.

[0069] Flux concentrator foil can be wound, particularly with the ends overlapping or adjacent to each other, to form a tubular flux concentrator or flux concentrator sleeve. The overlapping or adjacent ends can be attached to each other. Similarly, the overlapping or adjacent ends can be loosely overlapping or loosely adjacent to each other.

[0070] Specifically, the flux concentrator foil may be wound as a single winding to form a tubular flux concentrator or flux concentrator sleeve comprising a single winding of the flux concentrator foil. Alternatively, the flux concentrator foil may be wound as multiple turns / windings to form a tubular flux concentrator or flux concentrator sleeve comprising multiple, in particular, helical windings of the flux concentrator foil.

[0071] The flux concentrator foil can also be helically wound in the axial direction relative to the winding axis to form a tubular flux concentrator or flux concentrator sleeve comprising one or more helical windings of flux concentrator foil overlapping each other.

[0072] Flux concentrator foils can also be individual concentric windings wound on top of each other. That is, a flux concentrator can comprise multiple flux concentrator foils wound with individual concentric single (turn) windings wound on top of each other. Similarly, flux concentrator foils can also be individual multiple spirals or multiple windings wound on top of each other. That is, a flux concentrator can comprise multiple flux concentrator foils wound with individual concentric multiple spiral or coil (turn) windings wound on top of each other.

[0073] Furthermore, the flux concentrator may include multiple flux concentrator foils arranged side by side next to each other, wherein each flux concentrator foil is wound with a single winding, or with multiple helical windings overlapping each other, or with individual concentric windings stacked on top of each other.

[0074] Constructions comprising multiple (particularly multiple helical or coiled) windings of flux concentrator foil, or multiple individual concentric windings stacked on top of each other, can advantageously be used to generate multilayer flux concentrator foils or multilayer flux concentrators, wherein each winding corresponds to one layer. For example, a flux concentrator may comprise two, three, four, five, six, or more than six helical or coiled windings or multiple individual concentric windings. Thus, such multilayer flux concentrator foils or multilayer flux concentrators can have a thickness substantially corresponding to the thickness of a single layer or foil multiplied by the number of windings or layers. For example, when the foil has a thickness between 0.02 mm and 0.25 mm, particularly between 0.05 mm and 0.2 mm, and preferably between 0.1 mm and 0.15 mm, the multilayer flux concentrator foil or a multilayer flux concentrator comprising six layers may have a thickness between 0.12 mm and 1.5 mm, particularly between 0.3 mm and 1.2 mm, and preferably between 0.6 mm and 0.9 mm.

[0075] When the flux concentrator foil is wound in a single winding to form a tubular flux concentrator or flux concentrator sleeve, the flux concentrator foil can be force-fitted to the inner surface of the device housing due to the partial release of the elastic restoring force of the wound flux concentrator foil. That is, the elastic restoring force presses the flux concentrator foil radially outward against the inner surface of the device housing. In this configuration, the ends of the wound foil preferably loosely overlap or loosely abut each other. Advantageously, this configuration allows for simple installation of the flux concentrator, especially without the need for any additional fixing devices.

[0076] Flux concentrators can also be produced by directly extruding a flux concentrator foil into its final shape. Specifically, the flux concentrator may include or be an extruded flux concentrator foil, for example, an extruded tubular flux concentrator foil, an extruded flux concentrator foil sleeve, or an extruded cylindrical flux concentrator foil. The extruded tubular flux concentrator foil, extruded flux concentrator foil sleeve, or extruded cylindrical flux concentrator foil may have a wall thickness between 0.05 mm and 0.25 mm, preferably between 0.1 mm and 0.15 mm. The wall thickness may also be between 0.12 mm and 1.5 mm, particularly between 0.3 mm and 1.2 mm, preferably between 0.6 mm and 0.9 mm.

[0077] The induction heating device may include at least one sensor element as part of the device. Similarly, the at least one sensor element may also be an integral part of an aerosol-generating article comprising an aerosol-forming matrix to be heated. As part of the device, the at least one sensor element is arranged, or may be arranged, at least partially within the cavity to be in thermal proximity or thermal contact, preferably physical contact, with the aerosol-forming substrate during use.

[0078] As used herein, the term "receptor element" refers to a component capable of converting electromagnetic energy into heat when subjected to a changing magnetic field. This can be a result of at least one of hysteresis loss or eddy currents induced in the receptor, depending on the electrical and magnetic properties of the receptor material. In ferromagnetic or ferrimagnetic receptors, hysteresis loss occurs due to the transformation of magnetic domains within the receptor material under the influence of a changing magnetic field. If the receptor is conductive, eddy currents can be induced. In the case of conductive ferromagnetic or ferrimagnetic receptors, heat can be generated due to both eddy currents and hysteresis loss.

[0079] Therefore, the sensor element can be formed from any material capable of being inductively heated to a temperature sufficient to generate aerosols from the aerosol-forming matrix. Preferred sensor elements comprise metals or carbon. Preferred sensor elements may comprise ferromagnetic materials, such as ferrite iron or ferromagnetic steel or stainless steel. Suitable sensor elements may be aluminum or include aluminum. Preferred sensor elements may be formed from 400 series stainless steel, such as grade 410, 420, or 430 stainless steel.

[0080] The receptor element may include a variety of geometries. The receptor element may include or may be a receptor needle, receptor rod, receptor plate, receptor strip, or receptor plate. When the receptor element is part of an aerosol generation apparatus, the receptor needle, receptor rod, receptor plate, receptor strip, or receptor plate may protrude into a cavity of the apparatus, preferably toward an opening of the cavity, to insert an aerosol-generated article into the cavity.

[0081] The receptor element may include or may be a filament receptor, a mesh receptor, or a core receptor. Similarly, the receptor element may include or may be a receptor sleeve, a receptor cup, a cylindrical receptor, or a tubular receptor. Preferably, the internal voids of the receptor sleeve, receptor cup, cylindrical receptor, or tubular receptor are configured to removably receive at least a portion of the aerosol-forming matrix or an aerosol-generating article comprising the aerosol-forming matrix to be heated.

[0082] The aforementioned receptor element may have any cross-sectional shape, such as circular, elliptical, square, rectangular, triangular or any other suitable shape.

[0083] As used herein, the term "aerosol generating device" generally refers to an electrically operated device capable of interacting with at least one aerosol forming matrix, particularly with an aerosol forming matrix disposed within an aerosol generating article, in order to generate an aerosol by heating the matrix. Preferably, the aerosol generating device is a suction device for generating an aerosol that can be directly inhaled by a user through their mouth. In particular, the aerosol generating device is a handheld aerosol generating device.

[0084] In addition to the induction coil, the induction heating device may include an alternating current (AC) generator. This AC generator may be powered by the power source of the aerosol generating device. The AC generator is operatively coupled to at least one induction coil. Specifically, the at least one induction coil may be an integral part of the AC generator. The AC generator is configured to generate a high-frequency oscillating current passing through the induction coil to generate a changing magnetic field. The AC current may be continuously supplied to the induction coil after system activation, or it may be supplied intermittently, for example, on a per-port suction basis.

[0085] Preferably, the induction heating device includes a DC / AC converter connected to a DC power supply comprising an LC network, wherein the LC network comprises a capacitor and an induction coil connected in series.

[0086] The induction heating device is preferably configured to generate a high-frequency changing magnetic field. As mentioned herein, the high-frequency changing magnetic field can be between 500 kHz (kilohertz) and 30 MHz (megahertz), particularly between 5 MHz (megahertz) and 15 MHz (megahertz), and preferably in the range between 5 MHz (megahertz) and 10 MHz (megahertz).

[0087] The aerosol generating apparatus may also include a controller configured to control the operation of the device. Specifically, the controller may be configured to control the operation of the induction heating device, preferably in a closed-loop configuration, for controlling the heating of the aerosol forming matrix to a predetermined operating temperature. The operating temperature for heating the aerosol forming matrix may be at least 180 degrees Celsius, particularly at least 300 degrees Celsius, preferably at least 350 degrees Celsius, more preferably at least 370 degrees Celsius, and most preferably at least 400 degrees Celsius. These temperatures are typical operating temperatures for heating but not burning the aerosol forming matrix. For example, the operating temperature is between 180 degrees Celsius and 370 degrees Celsius, particularly between 180 degrees Celsius and 240 degrees Celsius or in the range between 280 degrees Celsius and 370 degrees Celsius. Generally, the operating temperature may depend on at least one of the type of aerosol forming matrix to be heated, the construction of the sensor, and the arrangement of the sensor relative to the aerosol forming matrix when using the system. For example, when the sensor is constructed and arranged to surround the aerosol-forming matrix, for example, during system use, the operating temperature can be in the range of 180 degrees Celsius to 240 degrees Celsius. Similarly, when the sensor is constructed, for example, within the aerosol-forming matrix during system use, the operating temperature can be in the range of 280 degrees Celsius to 370 degrees Celsius. The operating temperature described above preferably refers to the temperature of the sensor in use.

[0088] The controller may include a microprocessor, such as a programmable microprocessor, microcontroller, or application-specific integrated circuit (ASIC), or other electronic circuitry capable of providing control. The controller may include other electronic components, such as at least one DC / AC inverter and / or power amplifier, such as a Class C, Class D, or Class E power amplifier. In particular, the induction heating device may be part of the controller.

[0089] The aerosol generating device may include a power source, particularly a DC power source, configured to provide a DC power supply voltage and a DC power supply current to the induction heating device. Preferably, the power source is a battery, such as a lithium iron phosphate battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require charging; that is, the power source may be rechargeable. The power source may have a capacity that allows sufficient energy to be stored for one or more user experiences. For example, the power source may have sufficient capacity to allow continuous aerosol generation in time intervals of approximately six minutes or multiples of six minutes. In another example, the power source may have sufficient capacity to allow a predetermined number of suctions or intermittent activation of the induction heating device.

[0090] The aerosol generating apparatus may include a body, which preferably includes at least one of an induction heating device (in particular at least one induction coil), a flux concentrator, a controller, a power supply, and at least a portion of a cavity.

[0091] In addition to the main body, the aerosol generating apparatus may also include a mouthpiece, particularly where the aerosol generating article to be used with the apparatus does not include a mouthpiece. The mouthpiece may be mounted to the main body of the apparatus. The mouthpiece may be configured to close a receiving cavity when mounted to the main body. To attach the mouthpiece to the main body, the proximal portion of the main body may include a magnetic or mechanical mounting element, such as a bayonet mount or snap-fit ​​mount, which engages with a corresponding element at the distal portion of the mouthpiece. Where the apparatus does not include a mouthpiece, the aerosol generating article to be used with the aerosol generating apparatus may include a mouthpiece, such as a filter tip section.

[0092] Aerosol generating apparatus may include at least one air outlet, such as an air outlet in a mouthpiece (if present).

[0093] Preferably, the aerosol generating device includes an air path extending from at least one air inlet through a receiving cavity, and possibly further extending, if present, to an air outlet in the mouthpiece. Preferably, the aerosol generating device includes at least one air inlet in fluid communication with the receiving cavity. Therefore, the aerosol generating system may include an air path extending from at least one air inlet into the receiving cavity, and may further enter the user's mouth through an aerosol forming matrix within the article and the mouthpiece.

[0094] At least one induction coil and flux concentrator may be part of an induction module arranged within the device housing and forming at least a portion of the cavity of the device or arranged circumferentially around at least a portion of the cavity of the device, particularly arranged removably.

[0095] In this regard, the present invention also provides a sensing module that can be arranged within an aerosol generating apparatus to form at least a portion of a cavity of the apparatus or to be circumferentially arranged around at least a portion of a cavity of the apparatus, wherein the cavity is configured to removably receive an aerosol forming matrix to be inductively heated. The sensing module includes at least one induction coil for generating a changing magnetic field within the cavity during use, wherein when the sensing module is arranged in the apparatus, the at least one induction coil is arranged around at least a portion of the receiving cavity. The sensing module also includes a flux concentrator arranged circumferentially around at least a portion of the at least one induction coil and configured to twist the changing magnetic field of the induction coil toward the cavity during use when the sensing module is arranged in the apparatus. The flux concentrator comprises, or is made from, a flux concentrator foil according to the invention and as described herein. That is, the flux concentrator foil is a multilayer flux concentrator foil having at least one magnetic layer laminated with at least a first support layer, wherein the magnetic layer comprises a plurality of separate fragments of a soft magnetic alloy.

[0096] Other features and advantages of the induction module, particularly the induction coil and flux concentrator, have been described with respect to the aerosol generating device and are equally applicable.

[0097] According to another aspect of the invention, an aerosol generation system is also provided, comprising an aerosol generation apparatus according to the invention and as described herein. The system also includes an aerosol generation article for use with the apparatus, wherein the article comprises an aerosol forming matrix to be inductively heated by the apparatus. The aerosol generation article is at least partially received or can be received in a cavity of the apparatus.

[0098] As used herein, the term "aerosol generation system" refers to a combination of an aerosol generation article as further described herein and an aerosol generation apparatus according to the invention and as described herein. In the system, the article and apparatus cooperate to generate inhalable aerosols.

[0099] As used herein, the term "aerosol-generating article" refers to an article comprising at least one aerosol-forming matrix that releases volatile compounds capable of forming aerosols upon heating. Preferably, the aerosol-generating article is a heated aerosol-generating article. That is, the aerosol-generating article comprises at least one aerosol-forming matrix intended to be heated rather than burned in order to release volatile compounds capable of forming aerosols. The aerosol-generating article may be a consumable, particularly one to be discarded after a single use. For example, the article may be a cartridge comprising a liquid aerosol-forming matrix to be heated. Alternatively, the article may be a rod-shaped article, particularly a tobacco article, similar to a conventional cigarette.

[0100] As used herein, the term "aerosol forming matrix" refers to a matrix formed by or containing an aerosol forming material that, upon heating, releases volatile compounds to generate aerosols. The aerosol forming matrix is ​​intended to be heated, rather than burned, to release the volatile compounds that form the aerosols. An aerosol forming matrix can be a solid aerosol forming matrix, a liquid aerosol forming matrix, a gel-like aerosol forming matrix, or any combination thereof. An aerosol forming matrix may include tobacco-containing material containing volatile tobacco flavor compounds that are released from the matrix upon heating. Alternatively or additionally, an aerosol forming matrix may include non-tobacco materials. An aerosol forming matrix may also include an aerosol forming agent. Examples of suitable aerosol forming agents are glycerol and propylene glycol. An aerosol forming matrix may also include other additives and ingredients, such as nicotine or flavorings. The aerosol forming matrix can also be a paste-like material, including porous material pouches of the aerosol forming matrix, or loose tobacco mixed with a gelling agent or adhesive, which may include common aerosol forming agents such as glycerol, and is compressed or molded into rods.

[0101] As previously described, at least one sensor element for inductively heating the aerosol-forming matrix may be an integral part of the aerosol-generating article, rather than a part of the aerosol-generating apparatus. Therefore, the aerosol-generating article may include at least one sensor element positioned in thermal proximity or thermal contact with the aerosol-forming matrix, such that, in use, when the article is received in the cavity of the apparatus, the sensor element can be inductively heated by the inductive heating device.

[0102] Other features and advantages of the aerosol generation system according to the invention have been described with respect to the aerosol generation apparatus and are equally applicable.

[0103] According to another aspect of the invention, a method for manufacturing a multilayer flux concentrator foil for an aerosol generating apparatus according to the invention and as described herein is also provided. The method includes:

[0104] - Provide a multilayer flux concentrator foil, the multilayer flux concentrator foil having at least one magnetic layer of a soft magnetic alloy laminated with at least a first support layer;

[0105] -By applying an external force transversely to the foil plane to the flux concentrator foil, the at least one magnetic layer is broken into multiple fragments; and

[0106] - The flux concentrator foil is stretched by pulling the flux concentrator foil under a tensile force parallel to the plane of the foil.

[0107] In particular, stretching the flux concentrator foil by pulling can include pulling the flux concentrator foil across at least one edge, and more particularly across only one edge, under a tensile force parallel to the plane of the foil.

[0108] According to the invention, it has been found that by first applying an external force transverse to the foil plane to the flux concentrator foil, and then stretching the flux concentrator foil under a tensile force parallel to the foil plane, particularly by stretching it past at least one edge, the magnetic layer of the flux concentrator foil can be reliably fragmented into multiple separate fragments. The first step results in the magnetic layer fracturing into multiple fragments, while the second step causes the fragments to fractured into even smaller fragments, and (most importantly) be pulled apart to separate from each other. Advantageously, due to the fragments being pulled apart, the second step further reduces the AC resistance of the magnetic layer, and thus further reduces the eddy current loss of the magnetic layer of the flux concentrator foil.

[0109] Breaking at least one magnetic layer into multiple separate fragments may involve passing a flux concentrator foil through at least one pair of rollers, particularly counter-rotating rollers, which apply pressure to the flux concentrator foil passing through it. That is, pressure is applied to press the rollers together, causing the foil passing through it to be squeezed between the two rollers. At least one of the rollers may include multiple protrusions on its outer surface, each of which applies force locally to the flux concentrator foil transversely to the plane of the foil. A corresponding other roller may serve as a counter-rotating roller. Breaking may be enhanced when each of the rollers includes multiple protrusions on its outer surface. The multiple protrusions on the two rollers may be formed as complementary protrusions. For example, in operation, the protrusions of one roller may mate between the protrusions of a corresponding other roller. Alternatively, only one of the rollers may include multiple protrusions, while the corresponding other roller includes a smooth outer surface. Rollers with multiple protrusions may be made of metal (e.g., stainless steel). Rollers with smooth outer surfaces may be made of rubber. The rubber material should have suitable hardness to achieve breaking. The flux concentrator foil may pass through a pair of rollers or a series of pairs of rollers. To break at least one magnetic layer into multiple separate fragments, a breaking pressure of 4 to 8 bar, for example 6 bar, is applied transversely to the foil plane, specifically via rollers, to the flux concentrator foil. The flux concentrator foil can be unwound and rewound separately before and after passing through at least one pair of rollers. The unwound and rewound of the flux concentrator foil can be performed with a tensile force of 40-60 N (e.g., 50 N) and a winding speed of 5 to 10 m / min (e.g., 7 m / min) before and after passing through at least one pair of rollers.

[0110] The step of breaking at least one magnetic layer into multiple fragments by applying an external force transversely to the foil plane can be repeated multiple times, for example, once or twice. Therefore, the flux concentrator foil can pass through at least one pair of rollers two or three times. Alternatively, the flux concentrator foil can pass through at least one pair of rollers only once.

[0111] Pulling the flux concentrator foil across at least one edge may include pulling the flux concentrator foil back and forth, particularly repeatedly, for example, four to six times across at least one edge. Pulling back and forth enhances the separation of fragments.

[0112] Preferably, at least one edge is a sharp edge. That is, at least one edge may include a corner radius of up to 1 mm, particularly up to 0.3 mm, preferably up to 0.2 mm, and more preferably up to 0.15 mm.

[0113] The pulling over the edge can be performed at an angle between 60 and 120 degrees, particularly between 80 and 100 degrees, preferably 90 degrees. That is, the flux concentrator foil bends at this angle as it is pulled over the edge. This angle is measured between a portion of the foil upstream of the edge and a portion of the foil downstream of the edge.

[0114] During the pulling of the flux concentrator foil, the tensile force can be between 20 N and 60 N, particularly between 25 N and 40 N, for example, 30 N. These values ​​have proven particularly beneficial for pulling apart fragments. The flux concentrator foil can be pulled past the edge at speeds of 5 to 15 m / min, for example, 10 m / min.

[0115] The step of providing a multilayer flux concentrator foil having at least one magnetic layer of a soft magnetic alloy laminated with at least a first support layer may include at least one of the following:

[0116] -Provide strips made of or composed of soft magnetic alloys;

[0117] - Annealing of strips containing or made of soft magnetic alloys;

[0118] - Provide a first adhesive tape including a first support layer, wherein the first support layer is adhesive;

[0119] -Laminate the first support layer and a strip comprising a soft magnetic alloy or an annealed strip made of a soft magnetic alloy together to produce a first laminated arrangement;

[0120] The step of providing a multilayer flux concentrator foil may further include at least one of the following:

[0121] - Repeat the above steps of providing a strip, annealing the strip, providing an intermediate adhesive strip including an viscous (intermediate) support layer, and laminating the (intermediate) support layer and the (annealed) strip to produce an intermediate laminate arrangement including an intermediate adhesive strip that includes an intermediate support layer.

[0122] - Provide a second adhesive tape including a second support layer, wherein the second support layer is adhesive;

[0123] -Laminate a first lamination arrangement, an intermediate lamination arrangement, and a second adhesive tape to produce an (unsealed) multilayer flux concentrator foil, wherein the intermediate lamination arrangement is sandwiched between the first lamination arrangement and the second adhesive tape.

[0124] The thickness of the strip, comprising or made of a soft magnetic alloy, can be in the range of 15 micrometers to 25 micrometers, particularly in the range of 18 micrometers to 23 micrometers, for example, 21 micrometers. Preferably, the strip comprising or made of a soft magnetic alloy is disposed on a spool or bobbin. Before annealing the strip comprising or made of a soft magnetic alloy, the strip can be rewound from one spool or bobbin support to another one or more times to adjust the tension of the strip. For example, the strip comprising or made of a soft magnetic alloy can be rewound in a first step with a tensile force of 20 N (Newtons) ± 10%, and in a second step with a tensile force of 10 N (Newtons) ± 10%. The winding speed can be 30 m / min ± 10% during the first step and 20 m / min ± 10% during the second step.

[0125] The step of annealing a strip comprising or made of a soft magnetic alloy may include heating the strip comprising or made of a soft magnetic alloy at a temperature in the range of 450 degrees Celsius to 520 degrees Celsius (e.g., 495 degrees Celsius) for a period of time in the range of 300 minutes to 500 minutes (e.g., 450 minutes).

[0126] The first support layer of the first adhesive tape and the intermediate support layer of the intermediate adhesive tape may comprise an adhesive, particularly an adhesive based on non-PET (polyethylene terephthalate). The thickness of the first support layer and the intermediate support layer may be between 2 micrometers and 10 micrometers, particularly in the range between 2 micrometers and 5 micrometers, for example, 3 micrometers. In addition to the first / intermediate support layer, the first / intermediate adhesive tape may include a first release film and a second release film on both sides of the adhesive first / intermediate support layer before attaching the first / intermediate adhesive tape to the (annealed) strip. That is, the first and / or second release films are removed before attaching the adhesive first / intermediate support layer to any other object. Therefore, the step of laminating the first / intermediate support layer to the strip comprising or made of a soft magnetic alloy may include removing the first release film from the first / intermediate adhesive tape, attaching the (annealed) strip to the adhesive first / intermediate support layer on the side opposite to the second release film, and preferably reattaching the first release film on top of the (annealed) strip comprising or made of a soft magnetic alloy. The above steps can be achieved by: unwinding the first / intermediate adhesive tape and the (annealed) strip; removing the first release film, bringing the unwound (annealed) strip and the unwound adhesive first / intermediate tape (without the first release film) into contact with each other and attaching them together; reinstalling the first release film; applying pressure to the resulting first / intermediate laminate arrangement; and optionally rewinding the first / intermediate laminate arrangement. Unwinding the first / intermediate adhesive tape and the (annealed) strip can be done with a tensile force of 40-60 N (Newtons) (e.g., 50 N (Newtons)) and a winding speed of 5 to 10 m / min (e.g., 7 m / min). Similarly, rewinding the first / intermediate laminate arrangement can be done with a tensile force of 40-60 N (Newtons) (e.g., 50 N (Newtons)) and a winding speed of 5 to 10 m / min (e.g., 7 m / min).

[0127] Similarly, the second support layer of the second adhesive tape may include a PET (polyethylene terephthalate) based adhesive. The thickness of the second support layer may be in the range of 2 micrometers to 10 micrometers, particularly in the range of 2 micrometers to 5 micrometers, for example, 3 micrometers. In addition to the second support layer, the second adhesive tape may include a first release film and a second release film on both sides of the adhesive second support layer before the second adhesive tape is attached to the intermediate lamination arrangement. That is, the first and / or second release films are removed before the adhesive second support layer is attached to any other object. Therefore, the step of laminating the second support layer to the intermediate lamination arrangement may include removing the second release film from the second adhesive tape and attaching the adhesive second support layer to the intermediate lamination arrangement on the side opposite to the second release film. The above steps can be achieved by: unfolding the second adhesive tape, the first laminate arrangement, and the intermediate laminate arrangement; removing the second release film from the second adhesive tape; removing the first and second release films from the intermediate laminate arrangement, and removing the first release film from the first laminate arrangement; bringing the unfolded first laminate arrangement (without the first release film), the intermediate laminate arrangement (without the first and second release films), and the second adhesive tape (without the second release film) into contact with each other and attaching them together; applying pressure to the resulting (unsealed) multilayer flux concentrator foil and subsequently rewinding the multilayer flux concentrator foil. Unfolding the second adhesive tape, the first laminate arrangement, and the intermediate laminate arrangement can be performed using a tensile force of 40-60 N (e.g., 50 N) and a winding speed of 5 to 10 m / min (e.g., 7 m / min). Similarly, rewinding the multilayer flux concentrator foil can be performed using a tensile force of 40-60 N (e.g., 50 N) and a winding speed of 5 to 10 m / min (e.g., 7 m / min).

[0128] The aforementioned process can produce (unsealed) multilayer flux concentrator foil, which includes the following layers (from bottom to top):

[0129] - Adhesive (non-PET) first support layer (derived from the first laminate arrangement),

[0130] - The first magnetic layer of the (annealed) strip, the first magnetic layer comprising or made of a soft magnetic alloy (derived from the first laminate arrangement),

[0131] - Adhesive (non-PET) intermediate support layer (derived from intermediate lamination arrangement),

[0132] - A second magnetic layer of (annealed) strips, the second magnetic layer comprising or made of a soft magnetic alloy (derived from a second laminate arrangement), and

[0133] - Adhesive (PET-based) second support layer (derived from second adhesive tape).

[0134] Additionally, the multilayer flux concentrator foil may include a first release film (derived from a second adhesive tape) on top of the adhesive second support layer and a second release film (derived from a first adhesive tape in a first laminated arrangement) below the adhesive first support layer. The first release film (derived from the second adhesive tape) and the second release film (derived from the first adhesive tape in a first laminated arrangement) are removed before the multilayer flux concentrator foil is arranged around at least a portion of the induction coil of the aerosol generating device (where the multilayer flux concentrator foil will be used). Similarly, the first release film (derived from the second adhesive tape) and the second release film (derived from the first adhesive tape in a first laminated arrangement) may be removed before any other steps of the method described herein, particularly before sealing one or more cut edges of the (unsealed) flux concentrator, and even more particularly before attaching the adhesive sealing tape to one side or each side of the (unsealed) flux concentrator foil.

[0135] Alternatively, the method may include pulling the flux concentrator foil over at least one roller, particularly a series of rollers, under a tensile force parallel to the foil plane to bend the flux concentrator foil. Advantageously, this step can break the fragment into even smaller pieces, thus further reducing the AC resistance of the magnetic layer. Pulling the flux concentrator foil over at least one roller may be performed before pulling the flux concentrator foil over at least one edge.

[0136] The radius of at least one roller may be up to 50 mm, particularly up to 30 mm, and preferably up to 10 mm.

[0137] The tensile force used to pull the flux concentrator foil across at least one roller can be between 20 N (Newtons) and 60 N (Newtons), particularly between 25 N (Newtons) and 40 N (Newtons), for example, 30 N (Newtons).

[0138] The method may also include cutting the flux concentrator foil to a predetermined size. The cutting may be performed before the magnetic layer is broken into multiple pieces, or before the flux concentrator foil is pulled over at least one edge, or after the flux concentrator foil is pulled over at least one edge.

[0139] The method may also include sealing one or more cut edges of a flux concentrator foil cut to a specified size. Advantageously, this prevents debris from escaping laterally from the foil.

[0140] Sealing one or more cut edges of a (unsealed) multilayer flux concentrator foil cut to a specified size may include attaching a sealing adhesive tape to one or each side of the flux concentrator foil cut to a specified size, wherein the adhesive sealing tape has a width extension in a direction transverse to the opposite cut edges of the flux concentrator foil, said width extension being greater than the width extension of the flux concentrator foil cut to a specified size in the same direction (i.e., in a direction transverse to the opposite cut edges of the flux concentrator foil). As a result, the sealing adhesive tape on each side of the (unsealed) flux concentrator foil includes laterally projecting wings that can make adhesive contact with each other to seal the cut edges of the (unsealed) flux concentrator.

[0141] The adhesive sealing tape may include a three-layer adhesive sealing laminate comprising a PEN (polyethylene terephthalate)-based film sandwiched between a first adhesive layer and a second adhesive layer. Similarly, the adhesive sealing tape may include a three-layer adhesive sealing laminate comprising a PI (polyimide)-based film sandwiched between a first adhesive layer and a second adhesive layer. The thickness of the PEN (polyethylene terephthalate)-based film may be 2-5 micrometers, particularly 3 micrometers. Likewise, the thickness of the PI (polyimide)-based film may be 2-8 micrometers, particularly 5-7 micrometers. In general, the thickness of the three-layer adhesive sealing laminate may be 3-15 micrometers, particularly 4-13 micrometers, for example 5 micrometers, or 7 micrometers, or 9 micrometers, or 13 micrometers. The first and second adhesive layers of the three-layer sealing adhesive tape may comprise non-PET (polyethylene terephthalate)-based adhesives. In addition to the three-layer adhesive sealing laminate, the adhesive sealing tape may include a first release film on the first adhesive layer (opposite to a PEN or PI-based film) and a second release film on the second adhesive layer (opposite to a PEN or PI-based film), wherein one of the first and second release films will be removed before attaching the sealing adhesive tape to the flux concentrator foil cut to a certain size, and wherein the corresponding other of the first and second release films will be removed before arranging a sealed multilayer flux concentrator foil around at least a portion of the induction coil of the aerosol generating device (where multilayer flux concentrator foil will be used).

[0142] Similarly, the adhesive sealing tape may include a PET (polyethylene terephthalate) based adhesive film. The PET (polyethylene terephthalate) based adhesive film may have a thickness of 2-5 micrometers, particularly 3 micrometers. In addition to the PET-based adhesive film, the adhesive sealing tape may include a first and second release film clamping the PET (polyethylene terephthalate) based adhesive film, wherein one of the first and second release films is removed before attaching the sealing adhesive tape to a flux concentrator foil cut to a certain size, and wherein the corresponding other of the first and second release films is removed before arranging a sealed multilayer flux concentrator foil around at least a portion of the induction coil of the aerosol generating device (where a multilayer flux concentrator foil will be used).

[0143] Therefore, the step of attaching the sealing adhesive tape to the multilayer flux concentrator foil cut to a certain size may include removing one of the first and second release films from each of the two sealing adhesive tapes, and attaching the sealing adhesive tape to the multilayer flux concentrator foil, one on each side of the multilayer flux concentrator foil. The above steps can be achieved by: unfolding the two sealing adhesive tapes; removing one of the first and second release films from the sealing adhesive tapes, and (if applicable) removing the first release film (derived from the second adhesive tape) and the second release film (derived from the first adhesive tape in the first laminated arrangement) from the multilayer flux concentrator foil; bringing the multilayer flux concentrator foil (without the first and second release films) and the unfolded sealing adhesive tape (without either the first or second release film) into contact with each other and attaching them together (one sealing adhesive tape on each side of the multilayer flux concentrator foil), such that the laterally projecting wings of the sealing adhesive tapes are in adhesive contact with each other; applying pressure to the resulting sealed multilayer flux concentrator foil; and optionally rewinding the sealed multilayer flux concentrator foil.

[0144] The above process can produce a sealed multilayer flux concentrator foil, which includes the following layers (from bottom to top):

[0145] - A first three-layer adhesive sealing laminate, comprising a (PEN-based or PI-based) film sandwiched between a first adhesive layer and a second adhesive layer.

[0146] - Adhesive (non-PET based) first support layer (derived from the first laminate arrangement),

[0147] - The first magnetic layer of the (annealed) strip, the first magnetic layer comprising or made of a soft magnetic alloy (derived from the first laminate arrangement),

[0148] - Adhesive (non-PET based) intermediate support layer (derived from the second lamination arrangement),

[0149] - A second magnetic layer of (annealed) strips, the second magnetic layer comprising or made of a soft magnetic alloy (derived from the second laminate arrangement),

[0150] - Adhesive (PET-based) second support layer (derived from third adhesive tape), and

[0151] - A second or third adhesive sealing laminate, comprising a (PEN-based or PI-based) membrane sandwiched between a first adhesive layer and a second adhesive layer.

[0152] Similarly, the above process can produce a sealed multilayer flux concentrator foil, which comprises the following layers (from bottom to top):

[0153] -The first PET-based adhesive film,

[0154] - Adhesive (non-PET based) first support layer (derived from the first laminate arrangement),

[0155] - The first magnetic layer of the (annealed) strip, the first magnetic layer comprising or made of a soft magnetic alloy (derived from the first laminate arrangement),

[0156] - Adhesive (non-PET based) intermediate support layer (derived from the second lamination arrangement),

[0157] - A second magnetic layer of (annealed) strips, the second magnetic layer comprising or made of a soft magnetic alloy (derived from the second laminate arrangement),

[0158] - Adhesive (PET-based) second support layer (derived from third adhesive tape), and

[0159] - Second PET-based adhesive film.

[0160] Additionally, the sealed multilayer flux concentrator foil may include a first release film on top of the second or third layer adhesive sealing laminate or the second PET-based adhesive film, and a second release film below the first or third layer adhesive sealing laminate or the first PET-based adhesive film. The first and second release films may be derived from the sealing adhesive tape and will be removed before the sealed multilayer flux concentrator foil is arranged around at least a portion of the induction coil of the aerosol generating device (where the multilayer flux concentrator foil will be used).

[0161] Preferably, the flux concentrator foil is provided as a flux concentrator strip, and particularly as a continuous flux concentrator foil. Advantageously, this makes it possible to implement the method as a roll-to-roll process.

[0162] Further features and advantages of the method according to the invention have been described with respect to an aerosol-generating device and are equally applicable.

[0163] The invention is defined in the claims. However, a non-exhaustive list of non-limiting examples is provided below. Any one or more features of these examples may be combined with any one or more features of another example, embodiment or aspect described herein.

[0164] Example Ex1: An aerosol-generating device for generating an aerosol by inductively heating an aerosol-forming substrate, the device comprising:

[0165] - a device housing including a chamber configured to removably receive an aerosol-forming substrate to be heated;

[0166] - an inductive heating device including at least one induction coil for generating a varying magnetic field within the chamber, wherein the induction coil is arranged around at least a portion of the receiving chamber;

[0167] - a flux concentrator arranged around at least a portion of the induction coil and configured to distort the varying magnetic field of at least one inductive heating device towards the chamber during use of the device, wherein the flux concentrator comprises a multi-layer flux concentrator foil having at least one magnetic layer laminated to at least a first support layer, and wherein the magnetic layer comprises a plurality of discrete fragments of a soft magnetic alloy.

[0168] Example Ex2: The aerosol-generating device according to Example Ex1, wherein the soft magnetic alloy is a nanocrystalline soft magnetic alloy, particularly a nanocrystalline soft magnetic iron-based alloy.

[0169] Example Ex3: The aerosol-generating article according to any one of the preceding examples, wherein the soft magnetic alloy comprises Fe 100-a-b-c-x-y-z Cu a M b T c Si x Z z and a composition of up to 0.5 atomic % contaminants, wherein M is one or more of Nb, Mo and Ta, T is one or more of V, Cr, Co and Ni, and Z is one or more of C, P and Ge, and wherein 0.5 atomic % < a < 1.5 atomic %, 2 atomic % ≤ b < 4 atomic %, 0 atomic % ≤ c < 5 atomic %, 12 atomic % < x < 18 atomic %, 5 atomic % < y < 12 atomic %, and 0 atomic % ≤ z < 2 atomic %.

[0170] Example Ex4: The aerosol-generating article according to any one of the preceding examples, wherein the soft magnetic alloy comprises Fe73.8 Nb3Cu1Si 15.6 B 6.6 The composition.

[0171] Example Ex5: An aerosol generating apparatus according to any one of the preceding examples, wherein the size of each individual fragment is at most 1 millimeter, particularly at most 750 micrometers or at most 500 micrometers.

[0172] Example Ex6: In any of the preceding examples, the aerosol generating apparatus wherein the average size of the plurality of separated fragments can be up to 1 millimeter, particularly up to 750 micrometers or up to 500 micrometers.

[0173] Example Ex7: In any of the preceding examples, the aerosol generating apparatus wherein the relative maximum permeability of the soft magnetic alloy is at least 100, particularly at least 1000, preferably at least 10000, and even more preferably at least 50000.

[0174] Example Ex8: An aerosol generating apparatus according to any one of the preceding examples, wherein the plurality of separated fragments are arranged in a pattern comprising a plurality of crack centers, wherein the plurality of cracks extend radially outward from each crack center in a mesh pattern.

[0175] Example Ex9: An aerosol generating apparatus according to any one of the preceding examples, wherein the multilayer flux concentrator foil comprises a plurality of adjacent magnetic layers.

[0176] Example Ex10: The aerosol generating apparatus according to Example Ex9, wherein an adhesive film, particularly an electrically insulating adhesive film, is arranged between each pair of adjacent magnetic layers.

[0177] Example Ex11: An aerosol generating apparatus according to any one of the preceding examples, wherein the multilayer flux concentrator foil includes a second support layer on one side of the at least one magnetic layer, or (if applicable) on one side of the plurality of adjacent magnetic layers opposite to the first support layer.

[0178] Example Ex12: An aerosol generating apparatus according to any one of the preceding examples, wherein at least one of the first support layer and (if present) the second support layer is an adhesive layer, an electrically insulating layer, or an electrically insulating adhesive layer.

[0179] Example Ex13: An aerosol generating apparatus according to any one of the preceding examples, wherein the gaps between the plurality of separated fragments are at least partially filled with an electrically insulating material, particularly the material of the first support layer, or (if present) the material of the second support layer, or (if present) the material of the adhesive film between the adjacent magnetic layers, or the matrix material of the soft magnetic alloy.

[0180] Example Ex14: The aerosol generating apparatus according to any one of the foregoing examples, wherein the thickness of the flux concentrator foil is between 0.02 mm and 0.25 mm, particularly between 0.05 mm and 0.2 mm, and preferably between 0.1 mm and 0.15 mm.

[0181] Example Ex15: An aerosol generating apparatus according to any one of the preceding examples, wherein a first dielectric package is arranged around at least a portion of the induction coil between the induction coil and the flux concentrator.

[0182] Example Ex16: An aerosol generating apparatus according to any one of the preceding examples, wherein a conductive shielding package is arranged around the flux concentrator.

[0183] Example Ex17: An aerosol generating apparatus according to any one of the preceding examples, wherein a second dielectric package is arranged around the flux concentrator, and in particular (if present) around the shielding package.

[0184] Example Ex18: The aerosol generating apparatus according to any one of the foregoing examples further includes at least one sensor element disposed at least partially within the cavity.

[0185] Example Ex19: The aerosol generating apparatus according to Example Ex18, wherein the sensor is a tubular sensor or a sensor sleeve.

[0186] Example Ex20: An aerosol generation system comprising an aerosol generation apparatus according to any one of the foregoing examples and an aerosol generation article that at least partially receives or can be received in a cavity of the apparatus, wherein the aerosol generation article comprises an aerosol forming matrix to be heated.

[0187] Example Ex21: According to the aerosol generation system of Example Ex20, the aerosol generation article includes at least one sensor, the at least one sensor being positioned in thermal proximity or thermal contact with the aerosol forming matrix, such that in use, when the article is received in the cavity of the device, the sensor can be inductively heated by the induction heating device.

[0188] Example Ex22: A method for manufacturing a multilayer flux concentrator foil for an aerosol generating apparatus according to any one of the foregoing examples, the method comprising:

[0189] - Provide a multilayer flux concentrator foil, the multilayer flux concentrator foil having at least one magnetic layer of a soft magnetic alloy laminated with at least a first support layer;

[0190] - The magnetic layer is broken into multiple separate fragments by applying an external force transversely to the foil plane onto the flux concentrator foil; and

[0191] - The flux concentrator foil is stretched by pulling the flux concentrator foil under a tensile force parallel to the plane of the foil.

[0192] Example Ex23: According to the method of Example Ex22, wherein breaking the magnetic layer into multiple separate fragments includes passing the flux concentrator foil through at least one pair of rollers, the at least one pair of rollers applying pressure to the flux concentrator foil passing through it, wherein at least one of the rollers includes multiple protrusions on its outer surface.

[0193] Example Ex24: According to the method described in Example Ex23, the other corresponding roller includes a smooth outer surface, or each of the rollers includes a plurality of protrusions on its outer surface.

[0194] Example Ex25: The method according to any one of Examples Ex22 to Ex25, wherein stretching the flux concentrator foil by pulling comprises pulling the flux concentrator foil over at least one edge, particularly over only one edge, under a tensile force parallel to the plane of the foil.

[0195] Example Ex26: According to the method of Example Ex25, pulling the flux concentrator foil over at least one edge includes pulling the flux concentrator foil back and forth, particularly repeatedly, preferably 4 to 6 times, over at least one sharp edge.

[0196] Example Ex27: According to any one of Examples Ex25 or Ex26, the at least one edge includes a corner radius of up to 1 mm, particularly up to 0.3 mm, preferably up to 0.2 mm, and more preferably up to 0.15 mm.

[0197] Example Ex28: The method according to any one of Examples Ex22 to Ex27, wherein the tensile force is in the range of 20N to 60N, particularly 25N to 40N, for example 30N.

[0198] Example Ex29: The method according to any one of Examples Ex22 to Ex28 further includes pulling the flux concentrator foil through at least one roller, particularly a series of rollers, under a tensile force parallel to the plane of the foil, so as to bend the flux concentrator foil.

[0199] Example Ex30: According to the method described in Example Ex29, the radius of the at least one roller is at most 50 mm, particularly at most 30 mm, preferably at most 10 mm.

[0200] Example Ex31: The method according to any one of Examples Ex29 or Ex30, wherein the tensile force is in the range of 20N to 60N, particularly 25N to 40N, for example 30N.

[0201] Example Ex32: The method according to any one of Examples Ex22 to Ex31, wherein the flux concentrator foil is provided as a flux concentrator strip.

[0202] Example Ex33: The method according to any one of Examples Ex22 to Ex32, wherein the flux concentrator foil is provided as a continuous flux concentrator foil.

[0203] Example Ex34: The method according to any one of Examples Ex22 to Ex33 further includes cutting the flux concentrator foil to a predetermined size.

[0204] Example Ex35: The method according to Example Ex34 further includes sealing one or more cut edges of the flux concentrator foil cut to a certain size.

[0205] Example Ex36: The method described in Examples Ex22 to Ex35, wherein the method is implemented as a roll-to-roll process.

[0206] Several examples will now be described further with reference to the accompanying drawings, in which:

[0207] Figure 1 A schematic longitudinal cross-sectional view of an aerosol generation system according to a first embodiment of the present invention is shown;

[0208] Figure 2 It is based on Figure 1 A detailed view of the sensing module;

[0209] Figure 3 , 4a -4b shows that, according to Figure 1 Details of the multilayer flux concentrator foil used in the device;

[0210] Figure 5-8 Different arrangements of the flux concentrator foil according to the present invention are shown;

[0211] Figure 9 An exemplary embodiment of a multilayer flux concentrator foil comprising multiple magnetic layers is schematically illustrated.

[0212] Figure 10 This is a detailed view of the sensing module according to a second embodiment of the present invention;

[0213] Figure 11 A schematic longitudinal cross-sectional view of an aerosol generation system according to another embodiment of the present invention is shown;

[0214] Figure 12-15 The various steps of the method according to the present invention are illustrated by way of example;

[0215] Figure 16 It shows that it can be used according to Figure 1 Details of another example of a device including a multilayer flux concentrator foil with multiple magnetic layers; and

[0216] Figure 17 The following is shown: sealed by sealing adhesive tape. Figure 16 Multilayer flux concentrator foil.

[0217] Figure 1 A schematic cross-sectional view of a first exemplary embodiment of the aerosol generation system 1 according to the present invention is shown. The system 1 is configured to generate aerosols by induction heating of an aerosol forming matrix 91. The system 1 includes two main components: an aerosol generation article 90 including the aerosol forming matrix 91 to be heated; and an aerosol generation device 10 used with the article 90. The device 10 includes a receiving cavity 20 for receiving the article 90, and an induction heating device for heating the matrix 91 within the article 90 when the article 90 is inserted into the cavity 20.

[0218] Article 90 has a rod shape similar to that of a conventional cigarette. In this embodiment, article 90 includes four elements arranged coaxially: a matrix element 91, a support element 92, an aerosol cooling element 94, and a filter tip section 95. The matrix element is arranged at the distal end of article 90 and includes an aerosol-forming matrix to be heated. The aerosol-forming matrix 91 may include, for example, a rolled sheet of homogenized tobacco material, which includes glycerol as an aerosol forming agent. The support element 92 includes a hollow core forming a central air passage 93. The filter tip section 95 serves as a mouthpiece and may include, for example, cellulose acetate fibers. All four elements are generally cylindrical elements arranged sequentially one after another. These elements have substantially the same diameter and are defined by an outer wrapping 96 made of cigarette paper to form a cylindrical rod. The outer wrapping 96 may wrap around the aforementioned elements such that the free ends of the wrapping overlap each other. The wrapping may also include an adhesive for adhering the overlapping free ends of the wrapping to each other.

[0219] Device 10 includes a generally rod-shaped body 11 formed by a generally cylindrical device housing. Within the distal portion 13, device 10 includes a power source 16, such as a lithium-ion battery, and circuitry 17 including a controller for controlling the operation of device 10, particularly for controlling the heating process. Within the proximal portion 14 opposite the distal portion 13, device 10 includes a receiving cavity 20. Cavity 20 is open at the proximal end 12 of device 10, thereby allowing article 90 to be easily inserted into receiving cavity 20.

[0220] The bottom portion 21 of the receiving cavity separates the distal portion 13 of the device 10 from the proximal portion 14 of the device 10, particularly from the receiving cavity 20. Preferably, the bottom portion is made of an insulating material such as PEEK (polyetheretherketone). Thus, the electronic components within the distal portion 13 can remain separate from aerosols or residues generated within the cavity 20 by the aerosol generation process.

[0221] The induction heating device of apparatus 10 includes an induction source comprising an induction coil 31 for generating an alternating magnetic field, particularly a high-frequency changing magnetic field. In this embodiment, the induction coil 31 is a helical coil circumferentially surrounding a cylindrical receiving cavity 20. The induction coil 31 is formed of wire and has multiple turns or windings extending along the length of the cavity 20. The wire can have any suitable cross-sectional shape, such as square, elliptical, or triangular. In this embodiment, the wire has a circular cross-section. In other embodiments, the wire may have a flat cross-sectional shape.

[0222] The induction heating device also includes a sensor element 60 disposed within the receiving cavity 20 to be subjected to a changing magnetic field generated by the induction coil 31. In this embodiment, the sensor element 60 is a sensor plate 61. The sensor plate is disposed at its distal end 64 at the bottom portion 21 of the receiving cavity 20 of the device. From there, the sensor plate 61 extends into the internal void of the receiving cavity 20 at the proximal end 12 of the device 10 toward an opening in the receiving cavity 20. The other end of the sensor plate 60 (that is, the distal free end 63) is tapered, allowing the sensor plate to penetrate the aerosol forming matrix 91 within the distal portion of the article 90.

[0223] When device 10 is actuated, a high-frequency alternating current passes through induction coil 31. This causes coil 31 to generate a changing magnetic field within cavity 20. Consequently, receptor plate 61 heats up due to eddy currents and / or hysteresis losses, depending on the magnetic and electrical properties of the material of receptor element 60. Receptor 60 then heats the aerosol-forming matrix 91 of article 90 to a temperature sufficient to form an aerosol. The aerosol can then be drawn downstream of article 90 for inhalation by a user.

[0224] The range of the high-frequency changing magnetic field can be between 500 kHz (kilohertz) and 30 MHz (megahertz), especially between 5 MHz (megahertz) and 15 MHz (megahertz), preferably between 5 MHz (megahertz) and 10 MHz (megahertz).

[0225] In this embodiment, the induction coil 31 is part of the induction module 30, which is arranged together with the proximal portion 14 of the aerosol generating device 10. The induction module 30 has a generally cylindrical shape coaxially aligned with the longitudinal central axis C of the generally rod-shaped device 10. Figure 1 It can be seen that the sensing module 30 forms at least a portion of the cavity 20 or at least a portion of the inner surface of the cavity 20.

[0226] Figure 2 The sensing module 30 is shown in more detail. In addition to the induction coil 31, the sensing module 30 also includes a tubular inner support sleeve 32 that carries the helically wound cylindrical induction coil 31. At one end, the tubular inner support sleeve 32 has an annular protrusion 34 extending circumferentially around the inner support sleeve 32 to hold the coil 31 in proper position on the inner support sleeve 32. The inner support sleeve 32 can be made of any suitable material, such as plastic. In particular, the inner support sleeve 32 can be at least a portion of the cavity 20, that is, at least a portion of the inner surface of the cavity 20.

[0227] Both the induction coil 31 and the internal support sleeve 32 (except for the protrusion 34) are surrounded by a tubular flux concentrator 33 extending along the length of the induction coil 3, the length of which can be in the range of 16 mm to 18 mm. The flux concentrator 33 is configured to twist the changing magnetic field generated by the induction coil 31 toward the cavity 20 during use of the device 10. Essentially, the flux concentrator 33 acts as a magnetic shield to reduce undesirable heating or interference from external objects. Additionally, the flux concentrator 33 twists the magnetic field lines within the internal volume of the induction module 30, thereby increasing the density of the magnetic field within the cavity 20. This increases the current generated within the sensor plate 61 located in the cavity 20. In this way, the electromagnetic field can be concentrated toward the cavity 20 to allow for more efficient heating of the sensor element 60.

[0228] According to the present invention, the flux concentrator 33 is made of a multilayer flux concentrator foil 35. Figure 3 (not drawn to scale) and Figures 4a-4b The corresponding portion of the multilayer flux concentrator foil 35 is shown in more detail. Figure 3 This is a cross-sectional view through the multilayer flux concentrator foil 35. Figure 4a This is a black and white photograph of a portion of the sample with magnetic layer 36. Figure 4b Shown in opposite colors according to Figure 4a A magnetic layer 36 is added to enhance the visibility of cracks and fragments 39. For example... Figure 3 As shown, the multilayer flux concentrator foil 35 according to the invention comprises three layers: a magnetic layer 36 of a soft magnetic alloy, a first support layer 37, and a second support layer 38, wherein the magnetic layer 36 is laminated between the first support layer 37 and the second support layer 38. According to the invention, the magnetic layer 36 comprises a plurality of separate fragments 39. Due to fragmentation, the formation of eddy currents in the magnetic layer 36 is partially suppressed, as the sheet-like fragments 39 are separated from each other and each individual fragment 39 thus provides only limited space for eddy current formation. Therefore, the fragmented magnetic layer 36 has a reduced AC resistance compared to a non-fragmented magnetic layer. As a result, when exposed to a changing magnetic field, there is no or only very little energy dissipation in the fragments 39, causing the flux concentrator foil 35 as a whole to heat up only slightly (if present). Therefore, most of the energy provided by the changing magnetic field can be dissipated in the sensor. Figures 4a-4b As shown, multiple separated fragments 39 can be arranged in a pattern comprising multiple crack centers, wherein multiple cracks extend radially outward from each crack center in a mesh pattern. As can be seen, the separated fragments each have a different fragment size. The average fragment size can be up to 1 millimeter, and particularly up to 500 micrometers.

[0229] Preferably, the soft magnetic alloy is, for example, a nanocrystalline soft magnetic alloy made of Vitroperm 800. Vitroperm 800 has a maximum relative permeability greater than 20.0000 at a magnetic field frequency of 50 Hz. Therefore, this material is particularly suitable for concentrating and guiding magnetic fields generated by induction coils. Moreover, Vitroperm 800 is quite brittle and therefore easily breaks into multiple fragments.

[0230] The first support layer 37 and the second support layer 38 are primarily used to protect the brittle magnetic layer 36, particularly by bonding the fragments 39 of the magnetic layer 36 into a laminated structure to prevent the fragmented magnetic layer 36 from detaching. For this purpose, the first support layer 37 and the second support layer 38 are preferably adhesive layers. For example, the first support layer 37 and the second support layer 38 may be made of transparent adhesive or plastic tape. Preferably, the materials of the first support layer 37 and the second support layer 38 are electrically insulating to prevent short circuits from the detached fragments 39.

[0231] In this embodiment, the magnetic layer 36 may have a layer thickness of 20 micrometers. The first support layer 37 and the second support layer 38 may each have a layer thickness of 22 micrometers. Therefore, the flux concentrator foil 35 as a whole may have a thickness of 64 micrometers.

[0232] exist Figure 1 and Figure 2 In the illustrated embodiment, the flux concentrator foil 35 is wound in a single winding to form a tubular flux concentrator or flux concentrator sleeve comprising a single winding of the flux concentrator foil 35 surrounding the induction coil 31. In principle, the flux concentrator foil 35 may be wound around the induction coil 31 in different ways. According to the first embodiment, as... Figure 5 As shown, the flux concentrator foil 35 can be wound with its free ends 351 adjacent to each other. That is, the longitudinal edges of the flux concentrator foil 35 extending along the length axis C of the aerosol generating device 10 are adjacent to each other. According to the second embodiment, as Figure 6 As shown, the flux concentrator foil 35 can be wound by overlapping each other at its free ends 351. That is, the longitudinal edges of the flux concentrator foil 35 extending along the length axis C of the aerosol generating device 10 are adjacent to each other. According to... Figure 7 In the third embodiment shown, the flux concentrator foil 35 can be wound with multiple windings to form a tubular flux concentrator or flux concentrator sleeve comprising multiple windings (particularly helical windings) of flux concentrator foil overlapping each other. Figure 8 In the fourth embodiment shown, the flux concentrator foils 35, 13 may also be spirally wound relative to the winding axis in the axial direction (that is, along the length axis C of the aerosol generating device) to form a tubular flux concentrator or flux concentrator sleeve comprising one or more spiral windings of the flux concentrator foils 35, 135.

[0233] Figure 9 A second embodiment of the multilayer flux concentrator foil 235 is shown. (Compared to...) Figure 2 and Figure 3 Compared to the embodiments shown, according to Figure 9 The multilayer flux concentrator foil 235 includes a plurality of magnetic layers 236 laminated between a first support layer 237 and a second support layer 238. Additionally, an electrically insulating adhesive film 270 is disposed between each pair of adjacent magnetic layers 236. Specifically, regarding... Figure 7 and Figure 8 The multi-winding configuration shown allows multiple magnetic layers 236 to limit the number of turns required for winding. Advantageously, this simplifies the manufacture of the flux concentrator.

[0234] Refer again Figure 1 and Figure 2 The flux concentrator foil 35 is directly wrapped around the induction coil 31, and there is essentially no radial gap between the induction coil 31 and the flux concentrator foil 35.

[0235] Figure 10 Another embodiment of the sensing module 130 is shown, wherein the flux concentrator foil 135 is radially spaced from the induction coil 131. That is, the aerosol generating apparatus includes a radial gap 181 between the induction coil 131 and the flux concentrator foil 135. In this embodiment, the gap 181 is filled with a first dielectric package 182. For example, the induction coil 131 may be wrapped with one or more layers of Kapton tape 182 to fill the radial gap 181 between the induction coil 131 and the flux concentrator 133. The gap 181 or the first dielectric material 182 may each have a radial extension in the range of 40 micrometers to 240 micrometers (e.g., 80 micrometers). Advantageously, the gap 181 can help reduce losses in the induction coil and increase losses in the sensor to be heated, that is, increase the heating efficiency of the aerosol generating apparatus. Alternatively, the gap may be an air gap. Moreover, according to Figure 10 The sensing module 130 includes a conductive shielding package 183 arranged around the flux concentrator to provide additional shielding to the external parts of the device via an electrically closed field loop. For example, the conductive shielding package 180 may be aluminum foil wound in one or more turns around the flux concentrator 135. In addition, the sensing module 130 includes a second dielectric package 185 made of Kapton tape arranged around the flux concentrator 135 and the shielding package 183 to protect both the flux concentrator 135 and the shielding package 183. Furthermore, with... Figure 1 and Figure 2 Compared to the embodiments shown, according to Figure 10The receptor element 160 in the illustrated embodiment is a receptor sleeve 161 disposed on the inner surface of the inner support sleeve 132 to surround the article when it is received in the receiving cavity. In addition, Figure 10 The embodiments shown are similar to Figure 1 and Figure 2 The embodiments shown are very similar. Therefore, the same or similar features are indicated by the same reference numerals but incremented by 100.

[0236] Figure 11 A schematic cross-sectional view of yet another embodiment of the aerosol generation system 1 according to the present invention is shown. In addition to the receptor, the system is connected to... Figure 1 The systems shown are the same. Therefore, the same reference numerals are used for the same features. Figure 1 Compared to the embodiments shown, according to Figure 11 The sensor 68 of the system is not part of the aerosol generating apparatus 10, but rather part of the aerosol generating article 90. In this embodiment, the sensor 68 includes a sensor strip 69 made of metal (e.g., stainless steel) located within the aerosol forming matrix of the matrix element 91. Specifically, the sensor 68 is arranged within the article 90 such that when the article 90 is inserted into the cavity 20 of the apparatus 10, the sensor strip 69 is arranged within the cavity 20, particularly within the induction coil 31, so that during use, the sensor strip 69 experiences the magnetic field of the induction coil 31.

[0237] Figure 12-15 Exemplary examples illustrate some steps of the method according to the invention for manufacturing a multilayer flux concentrator foil for an aerosol generating apparatus according to the invention. As further described above, the method particularly includes the step of breaking one or more magnetic layers of the multilayer flux concentrator foil into multiple fragments by applying an external force transversely to the foil plane. This can be achieved by passing the flux concentrator foil through at least one pair of counter-rotating rollers 710, 720, which press against each other, such that the foil passing through is compressed between the two rollers 710, 720. Figure 12 and Figure 13 As shown, at least one of the rollers 710 includes a plurality of protrusions 711 on its outer surface, each of which applies a force locally to the flux concentrator foil transversely to the foil plane. Figure 12 In this configuration, each of the upper roller 710 and the lower roller 720 includes a plurality of protrusions 711, 721 to enhance the fracturing effect. Preferably, the plurality of protrusions 711, 721 on the two rollers 710, 720 can be formed as complementary protrusions. For example, in operation, the protrusion 711 of the upper roller 710 can fit between the protrusions 721 of the lower roller 720. In contrast, as... Figure 13As shown, it is also possible that only one of the rollers 710 includes a plurality of protrusions 711, while the corresponding other roller 720 includes a smooth outer surface serving as the opposing surface of the protrusions 711. However, it should be noted that, for simplicity, Figure 12 and Figure 13 Only four rows of protrusions 711 and 721 on the respective rollers 710 and 720 are shown. However, the rollers preferably have more than four rows of protrusions evenly distributed around the circumference of the respective roller.

[0238] The method also includes the step of pulling the flux concentrator foil 35 across at least one edge 730 under a tensile force parallel to the foil plane. This is in Figure 14 As shown, arrow 731 indicates a tensile force. This step causes the fragment to break into even smaller pieces and (most importantly) be pulled apart to further separate them from each other. Advantageously, this further reduces the AC resistance of the magnetic layer and thus further reduces the eddy current loss in the magnetic layer of the flux concentrator foil. Preferably, at least one edge 730 includes a corner radius of up to 0.3 mm, particularly up to 0.2 mm, and preferably up to 0.15 mm. The foil 35 can be pulled over the edge 730 at an angle 732 in the range of 60 degrees to 120 degrees (e.g., as shown). Figure 14 The stretching force 731 used to pull the foil 35 over the edge 730 can be between 20N and 60N, particularly in the range between 25N and 40N, for example, 30N.

[0239] In addition, such as Figure 15 As shown, the method may include pulling the flux concentrator foil through a series of rollers 740 under a tensile force 741 parallel to the foil plane to bend the flux concentrator foil 35. Advantageously, this step can break the fragment into even smaller pieces, thus further reducing the AC resistance of the magnetic layer. This step may be performed before the flux concentrator foil is pulled through at least one edge.

[0240] Figure 16 Another example of a multilayer flux concentrator foil according to the invention is shown (not drawn to scale), comprising multiple magnetic layers. From bottom to top, according to Figure 16 The multilayer flux concentrator foil includes the following layers:

[0241] - Adhesive (non-PET) first support layer 340,

[0242] - A first magnetic layer 350, the first magnetic layer comprising or made of a soft magnetic alloy.

[0243] - Adhesive (non-PET) intermediate support layer 360,

[0244] - A second magnetic layer 370, the second magnetic layer comprising or made of a soft magnetic alloy, and

[0245] - Adhesive (PET-based) second support layer 380.

[0246] As described in more detail above, the multilayer flux concentrator foil can be sealed to prevent debris from escaping laterally from the foil. For this purpose, sealing adhesive tapes 330, 390 can be arranged according to... Figure 16 On one side or each side of the (unsealed) flux concentrator foil. This sealed multilayer flux concentrator foil is on Figure 17 As shown here, the adhesive sealing tapes 330, 390 have a width extension in a direction transverse to the opposite edges of the unsealed flux concentrator foil, said width extension being greater than the width extension of the unsealed flux concentrator foil in the same direction (i.e., in a direction transverse to the opposite edges of the unsealed flux concentrator foil). As a result, the sealing adhesive tapes 330, 390 on each side of the unsealed flux concentrator foil include laterally projecting wings 335, 395 that can make adhesive contact with each other to seal the edges of the (unsealed) flux concentrator. Therefore, according to Figure 17 Specific examples of sealed multilayer flux concentrator foils include the following layers (from bottom to top):

[0247] - First PET-based adhesive film 331 (first adhesive sealing tape 330),

[0248] - Adhesive (non-PET) first support layer 340,

[0249] - A first magnetic layer 350, the first magnetic layer comprising or made of a soft magnetic alloy.

[0250] - Adhesive (non-PET) intermediate support layer 360,

[0251] - Second magnetic layer 370, the second magnetic layer comprising or made of a soft magnetic alloy.

[0252] - Adhesive (PET-based) second support layer 380, and

[0253] - Second PET-based adhesive film 391 (second adhesive sealing tape 390).

[0254] The first PET-based adhesive film 331 and the second PET-based adhesive film 391 may have a thickness of 2-5 micrometers, particularly 3 micrometers. The thicknesses of the first support layer 340 and the second support layer 360 (non-PET based) and the third support layer 380 (PET-based) may be in the range of 2 to 10 micrometers, particularly in the range of 2 to 5 micrometers, for example, 3 micrometers. The thicknesses of the first magnetic layer 350 and the second magnetic layer 370 may be in the range of 15 to 25 micrometers, particularly in the range of 18 to 23 micrometers, for example, 21 micrometers.

[0255] Instead of the first PET-based adhesive film 331 and the second PET-based adhesive film 991, the first sealing strip 330 and the second sealing strip 390 may further include a first three-layer adhesive sealing laminate and a second three-layer adhesive sealing laminate, each including a (PEN-based or PI-based) film sandwiched between the first adhesive layer and the second adhesive layer. Figure 17 (Not shown in the image).

[0256] For the purposes of this specification and the appended claims, unless otherwise stated, all figures representing quantities, quantities, percentages, etc., shall be understood to be modified by the term "about" in all cases. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein. Thus, in this context, the number A is understood as A ± 5% A. In this context, the number A can be considered as a value within the general standard error for the measurement of the attribute modified by the number A. In some cases used in the appended claims, the number A may deviate from the percentage listed above, provided that the amount of deviation from A does not materially affect the essential and novel features of the claimed invention. Furthermore, all ranges include the disclosed maximum and minimum points, and include any intermediate ranges therein, which may or may not be specifically listed herein.

Claims

1. An aerosol generating apparatus for generating aerosols by induction heating of an aerosol-forming matrix, the aerosol generating apparatus comprising: A device housing, the device housing including a cavity configured to removably receive an aerosol forming matrix to be heated; An induction heating device, the induction heating device comprising at least one induction coil for generating a changing magnetic field within the cavity, wherein the induction coil is arranged around at least a portion of the receiving cavity; A flux concentrator, arranged around at least a portion of the induction coil and configured to distort a changing magnetic field of at least one induction heating device toward the cavity during use of the aerosol generating device, wherein the flux concentrator comprises a multilayer flux concentrator foil having at least one magnetic layer laminated with at least a first support layer, wherein the magnetic layer comprises a plurality of separate fragments of a soft magnetic alloy, wherein the plurality of separate fragments are arranged in a pattern comprising a plurality of crack centers, wherein the plurality of cracks extend radially outward from each crack center in a mesh pattern.

2. The aerosol generating apparatus according to claim 1, wherein the soft magnetic alloy is a metallic glass or a nanocrystalline soft magnetic alloy.

3. The aerosol generating device according to any one of the preceding claims, wherein the soft magnetic alloy comprises Fe 100-a-b-c-x-y-z Cu a M b T c Si x Z z and a composition of up to 0.5 atomic % of contaminants, wherein M is one or more of Nb, Mo and Ta, T is one or more of V, Cr, Co and Ni, and Z is one or more of C, P and Ge, and wherein 0.5 atomic % < a < 1.5 atomic %, 2 atomic % ≤ b < 4 atomic %, 0 atomic % ≤ c < 5 atomic %, 12 atomic % < x < 18 atomic %, 5 atomic % < y < 12 atomic %, and 0 atomic % ≤ z < 2 atomic %.

4. The aerosol generating apparatus according to claim 1, wherein the multilayer flux concentrator foil comprises a plurality of adjacent magnetic layers.

5. The aerosol generating apparatus according to claim 1, wherein the multilayer flux concentrator foil includes a second support layer on one side of the at least one magnetic layer.

6. The aerosol generating apparatus according to claim 4, wherein the multilayer flux concentrator foil includes a second support layer opposite to the first support layer on one side of the plurality of adjacent magnetic layers.

7. The aerosol generating apparatus according to claim 5 or 6, wherein at least one of the first support layer and the second support layer is an adhesive layer, an electrical insulating layer, or an electrical insulating adhesive layer.

8. The aerosol generating apparatus according to claim 1, wherein the gaps between the plurality of separated fragments are at least partially filled with an electrically insulating material.

9. The aerosol generating apparatus according to claim 1, wherein the gaps between the plurality of separated fragments are at least partially filled with the material of the first support layer, or at least partially filled with the matrix material of the soft magnetic alloy.

10. The aerosol generating apparatus of claim 5, wherein the gaps between the plurality of separated fragments are at least partially filled with at least one of the material of the first support layer or the material of the second support layer, or at least partially filled with the matrix material of the soft magnetic alloy.

11. The aerosol generating apparatus of claim 4, wherein the gaps between the plurality of separated fragments are at least partially filled with at least one of the material of the first support layer or the material of the adhesive film between adjacent magnetic layers, or at least partially filled with the matrix material of the soft magnetic alloy.

12. The aerosol generating apparatus of claim 6, wherein the gaps between the plurality of separated fragments are at least partially filled with at least one of the material of the first support layer, the material of the second support layer, or the material of the adhesive film between adjacent magnetic layers, or at least partially filled with the matrix material of the soft magnetic alloy.

13. The aerosol generating apparatus of claim 1, wherein a first dielectric package is arranged around at least a portion of the induction coil between the induction coil and the flux concentrator.

14. The aerosol generating apparatus according to claim 1, wherein the soft magnetic alloy is a nanocrystalline soft magnetic iron-based alloy.

15. A method for manufacturing a multilayer flux concentrator foil for an aerosol generating apparatus according to any one of the preceding claims, the method comprising: - Provide a multilayer flux concentrator foil, the multilayer flux concentrator foil having at least one magnetic layer of a soft magnetic alloy laminated with at least a first support layer; - The magnetic layer is broken into multiple separate fragments by applying an external force transversely to the foil plane to the flux concentrator foil; as well as - The flux concentrator foil is stretched by pulling the flux concentrator foil under a tensile force parallel to the plane of the foil.

16. The method of claim 15, wherein breaking the magnetic layer into a plurality of separate fragments comprises passing the flux concentrator foil through at least one pair of rollers, the at least one pair of rollers applying pressure to the flux concentrator foil passing through it, wherein at least one of the rollers includes a plurality of protrusions on its outer surface.

17. The method of claim 16, wherein the corresponding other roller includes a smooth outer surface, or wherein each of the rollers includes a plurality of protrusions on its outer surface.

18. The method according to any one of claims 15 to 17, wherein pulling the flux concentrator foil comprises pulling the flux concentrator foil across at least one edge under a tensile force parallel to the plane of the foil.

19. The method of claim 18, wherein pulling the flux concentrator foil comprises pulling the flux concentrator foil across only one edge under a tensile force parallel to the plane of the foil.

20. The method according to any one of claims 15 to 17, further comprising pulling the flux concentrator foil over at least one roller under a tensile force parallel to the plane of the foil to bend the flux concentrator foil.

21. The method of claim 20, further comprising pulling the flux concentrator foil through a series of rollers under a tensile force parallel to the foil plane to bend the flux concentrator foil.

22. The method according to any one of claims 15 to 17, further comprising cutting the flux concentrator foil to a predetermined size.

23. The method of claim 22 further comprises sealing one or more cut edges of the flux concentrator foil cut to a specified size.

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