Patent Description:
The aerosol generating device according to the invention is configured to operate with an aerosol generating substrate which presents for example a solid substrate able to form aerosol when being heated. Thus, such type of aerosol generating devices, also known as heat-not-burn devices, is adapted to heat, rather than burn, the substrate by conduction, convection and/or radiation, to generate aerosol for inhalation.

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in the past few years as an aid to assist habitual smokers wishing to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and rolling tobacco. Various devices and systems are available that heat or warm vaporizable substances as opposed to burning tobacco in conventional tobacco products.

A commonly available reduced-risk or modified-risk device is the heated substrate aerosol generation device or heat-not-burn device. Devices of this type generate aerosol or vapour by heating an aerosol substrate, also known as aerosol generating substrate, that typically comprises moist leaf tobacco or other suitable vaporizable material to a temperature typically in the range <NUM> to <NUM>. Heating an aerosol substrate, but not combusting or burning it, releases aerosol that comprises the components sought by the user but not the toxic and carcinogenic by-products of combustion and burning. Furthermore, the aerosol produced by heating the tobacco or other vaporizable material does not typically comprise the burnt or bitter taste resulting from combustion and burning that can be unpleasant for the user and so the substrate does not therefore require the sugars and other additives that are typically added to such materials to make the smoke and/or vapour more palatable for the user.

Heating of the aerosol generating substrate is usually carried out by a heating system integrated within the device. Particularly, in some aerosol generating devices, the heating system provided with a heating chamber is able to receive and heat the substrate by heat transfer.

<CIT>, <CIT>, <CIT> <CIT> and <CIT> disclose such aerosol generating devices.

However, in some cases, the heat transfer is not optimal. This can lead to an inhomogeneous heating of the substrate and deteriorate its aerosol forming capacities. In this case, the substrate is not used efficiently and at least some parts of it may be wasted. Additionally, it can deteriorate or modify the taste of the aerosol that is expected by the user.

One of the aims of the invention is to provide an aerosol generating device which ensures an efficient heating of an aerosol generating substrate.

For this purpose, the invention, as defined in claim <NUM>, relates to an aerosol generating device configured to operate with an aerosol generating substrate and comprising:.

By heating using at least two heating walls of the heating chamber, it is possible to improve heat transfer to the substrate. The substrate can notably be heated homogeneously and without heat loss. Additionally, the controller can choose an optimal heating profile for each operation state of the device. Such heating profile may comprise activating of both heaters or only one of them. Different heating profiles can be carried out by the controller at different instants of the vaping session and may be repeated with different frequencies and depending on different external/internal conditions. Additionally, a heating profile can be chosen be the controller basing on at least one parameter like for example the temperature of at least one heater or of the substrate or of the aerosol.

According to the invention, said group of heating profiles comprises at least:.

Thanks to these features, the heating elements can be operated simultaneously or separately. For example, the heating elements can be operated simultaneously when it is necessary to increase rapidly the substrate temperature. Only one of the heaters may be operated when it is necessary to maintain the substrate temperature substantially unchanged.

According to the invention, the controller is configured to choose the first heating profile during a pre-heating mode of operation of the device and the second heating profile during a floating mode of operation of the device.

Thanks to these features, it is possible to render operable the aerosol generating device to generate aerosol after it has been switched, in a very fast way. Additionally, when it is no more necessary to heat strongly the substrate, as for example during the floating mode of operation, only one heater can be operated to avoid overheating of the substrate.

According to some embodiments, the first target temperature and the second target temperature are equal to a same value, said value being comprised between <NUM> and <NUM>, advantageously between <NUM> and <NUM>.

Thanks to these features, it is possible to avoid burning the substrate and consequently, emission of burnt and unpleasant elements for the user.

According to some embodiments, the controller is further configured to operate, after having carried out the second heating profile, according to at least one heating profile chosen in the group comprising at least:.

Thanks to these features, it is possible to ensure an optimal operation of the device and optimal heat transfer, notably during the floating mode of operation of the device.

According to some embodiments, the heating chamber extends along the device axis and defines a rectangular cross-sectional shape having a first pair of walls facing each other and forming chamber lateral walls, and a second pair of walls facing each other and forming said heating walls.

Thanks to these features, it is possible to obtain a more homogeneous heat transfer inside the substrate.

According to some embodiments, each heating wall at least <NUM> times, advantageously <NUM> times and more advantageously <NUM> times, wider than each chamber lateral wall.

Thanks to these features, the non-heated lateral surfaces of the aerosol generating substrate can be neglected. Thus, the heat transfer inside the substrate can be more optimal.

According to some embodiments, each heating wall defines a contact surface designed to be in a tight contact with an external surface of the aerosol generating substrate when the aerosol generating substrate is inserted into the heating chamber.

Thanks to these features, heat transfer between the heating wall and the substrate can be further improved.

According to some embodiments, each heating element is attached to an outer surface of the corresponding heating wall, opposite to the contact surface of this heating wall.

Thanks to these features, the heating element may be arranged outside the heating chamber while ensuring an optimal heat transfer with the substrate.

According to some embodiments, each chamber lateral wall is designed to be spaced out from an external surface of the aerosol generating substrate when the aerosol generating substrate is inserted into the heating chamber.

Thanks to these features, an airflow channel can be formed between the lateral walls of the chamber and the substrate. This channel can be used to conduct fresh air from outside of the device until a flow inlet of the aerosol generating substrate. This makes it possible to provide the heating chamber only with one opening, i.e. the opening used for inserting the substrate. The opposite end of the heating chamber may be sealed. This can reduce heat loss from the chamber.

According to some embodiments, the heating chamber is configured to compress the heater part of the aerosol generating substrate when it is received in the heating chamber.

Thanks to these features, heat transfer inside the aerosol generating substrate can be further improved. Indeed, compressing the substrate leads to expulsion of air bubbles formed inside the chamber and acting thus as thermal insulators.

According to some embodiments, each heating element is attached to an outer surface of the heating chamber.

According to some embodiments, each heating element is a polyimide film heater.

Thanks to these features, the heating elements can be thin and can be used inside the aerosol generating device while keeping a compact shape of the device.

According to some embodiments, further comprising insulator arranged between an outer surface of the heating chamber and an inner surface of the device body.

Thanks to these features, the device body can be thermally isolated from the heating chamber. This reduces the risks of the device external surface overheating and consequently, of user's injuring.

According to some embodiments, the heating chamber is made of a stainless steel.

Thanks to these features, the walls of the heating chamber can define good heat transfer properties.

The diclosure furthermore relates to an assembly comprising an aerosol generating device as described above and an aerosol generating substrate.

As used herein, the term "aerosol generating device" or "device" may include a vaping device to deliver an aerosol to a user, including an aerosol for vaping, by means of a heater element explained in further detail below. The device may be portable. "Portable" may refer to the device being for use when held by a user. The device may be adapted to generate a variable amount of aerosol, e.g. by activating the heater element for a variable amount of time (as opposed to a metered dose of aerosol), which can be controlled by a trigger. The trigger may be user activated, such as a vaping button and/or inhalation sensor. The inhalation sensor may be sensitive to the strength of inhalation as well as the duration of inhalation to enable a variable amount of vapour to be provided (so as to mimic the effect of smoking a conventional combustible smoking article such as a cigarette, cigar or pipe, etc.). The device may include a temperature regulation control to drive the temperature of the heater and/or the heated aerosol generating substance (aerosol pre-cursor) to a specified target temperature and thereafter to maintain the temperature at the target temperature that enables efficient generation of aerosol.

As used herein, the term "aerosol" may include a suspension of vaporizable material as one or more of: solid particles; liquid droplets; gas. Said suspension may be in a gas including air. Aerosol herein may generally refer to/include a vapour. Aerosol may include one or more components of the vaporizable material.

As used herein, the term "vaporizable material" or "precursor" may refer to a smokable material which may for example comprise nicotine or tobacco and an aerosol former. Tobacco may take the form of various materials such as shredded tobacco, granulated tobacco, tobacco leaf and/or reconstituted tobacco. Suitable aerosol formers include: a polyol such as sorbitol, glycerol, and glycols like propylene glycol or triethylene glycol; a non-polyol such as monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin or vegetable glycerin. In some embodiments, the aerosol generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also comprise at least one of a gelling agent, a binding agent, a stabilizing agent, and a humectant.

<FIG> shows an aerosol generating device <NUM> according to the first embodiment. The aerosol generating device <NUM> is intended to operate with an aerosol generating substrate <NUM> shown in more detail on <FIG>.

In reference to <FIG>, the aerosol generating substrate <NUM> is for example a flat-shaped cuboid extending along a substrate axis X and having external dimensions LxWxD. In a typical example, the length L of the substrate according to the substrate axis X equals substantially to <NUM> while its width W and depth D are substantially equal respectively to <NUM> and <NUM>,<NUM>. According to different examples, the values L, W and D can be selected within a range of +/- <NUM>%, for example. The depth D of the substrate <NUM> is formed by a pair of parallel walls 13A, 13B, called hereinafter substrate lateral walls 13A, 13B, and the width W of the substrate is formed by a pair of parallel walls 14A, 14B, called hereinafter substrate contact walls 14A, 14B. According to other embodiments, the aerosol generating substrate <NUM> can have any other suitable shape and/or external dimensions. For example, the aerosol generating substrate <NUM> may form a circular tube shape.

The aerosol generating substrate <NUM> comprises a heater part <NUM> and a mouthpiece part <NUM> arranged along the substrate axis X. In some embodiments, the aerosol generating substrate <NUM> may comprise only the heater part <NUM>. The heater part <NUM> may for example be slightly longer than the mouthpiece part <NUM>. For example, the length L2 of the heater part <NUM> according to the substrate axis X may be substantially equal to <NUM> and the length L1 of the mouthpiece part <NUM> according to the substrate axis X may be substantially equal to <NUM>. The heater part <NUM> defines an abutting end <NUM> of the substrate <NUM> and the mouthpiece part <NUM> defines a mouth end <NUM> of the substrate <NUM>. The heater part <NUM> and the mouthpiece part <NUM> may be fixed one to the other by a unique wrapper extending around the substrate axis X. In other embodiments, the parts <NUM>, <NUM> may be wrapped by different wrappers and fixed one to the other by any other suitable mean. The or each wrapper may, for example, comprise paper and/or non-woven fabric and/or aluminium. The or each wrapper may be porous or air impermeable. The or each wrapper forms a plurality of airflow channels extending inside the substrate <NUM> between the abutting end <NUM> and the mouth end <NUM>.

The heater part <NUM> is intended to be heated by a heater (using a heating chamber in the present example) and comprises vaporizable material as defined above. According to the first and the second embodiments, the mouthpiece part <NUM> is intended to be received inside a mouthpiece as it will be explained in further detail below. According to other embodiments, the mouthpiece part <NUM> forms itself a mouthpiece intended to be in contact with the user's mouth and/or lips. The mouthpiece part <NUM> comprises a core <NUM> acting for example like a filter. The core <NUM> may for example be a foam, or packed strands or fibres. The core <NUM> may be formed through an extrusion and/or rolling process into a stable shape. The substrate may be shaped to provide one or more airflow channels. In the particular example of <FIG>, the mouthpiece part <NUM> defines a plurality of venting holes <NUM> arranged for example according to the whole perimeter of the mouthpiece part <NUM> along two axis perpendicular to the substrate axis X. In other words, according to this example, the venting holes <NUM> are arranged on each wall of the substrate among the substrate lateral walls 13A, 13B and the substrate contact walls 14A, 14B. According to another example, the venting holes <NUM> are arranged only on the substrate contact walls 14A, 14B or preferably, only on one of the substrate contact walls 14A, 14B. In both examples, the venting holes <NUM> may be aligned perpendicularly to the substrate axis on the or each corresponding wall of the substrate <NUM>, and can be spaced by a same distance. The venting holes <NUM> allow fresh air entering inside the substrate <NUM> to achieve particular vaping/tasting effects.

Referring again to <FIG>, the aerosol generating device <NUM> comprises a device body <NUM> extending along a device axis Y and forming at least one side wall <NUM> of the device <NUM>. The device body <NUM> comprises a mouthpiece <NUM> and a housing <NUM> arranged successively according to the device axis Y. According to the first embodiment, the mouthpiece <NUM> and the housing <NUM> form two different pieces. Particularly, according to this embodiment, the mouthpiece <NUM> is designed to be fixed on or be received in an insertion opening <NUM> formed at one of the ends of the housing <NUM>. This opening <NUM> extends perpendicularly to the device axis Y as it is shown on <FIG> where the mouthpiece <NUM> is removed from the housing <NUM>.

In each cross section, the housing <NUM> may for example form a substantially rectangular shape with rounded edges. In this case, the housing <NUM> with the mouthpiece <NUM> form at least four side walls <NUM>. According to other embodiments, the housing <NUM> can have a round cross-sectional shape. In this case, it can form with the mouthpiece <NUM> only one side wall <NUM>. The housing <NUM> can be sealed at the end opposite to the insertion opening <NUM> receiving the mouthpiece <NUM>. The housing <NUM> can be formed from a single piece or several assembled pieces made of any suitable material like aluminium or plastic. In some embodiments, the material of the housing <NUM> can be a thermally conductive material. In some other embodiments, it can be a thermally insulating material. In some embodiments, the housing <NUM> can form on the corresponding part of the device side wall <NUM> one or several openings suitable for arranging control and/or visual elements. For example, such element may comprise control buttons, touch panels, screens, LEDs, etc. Particularly, in the example of <FIG>, the housing <NUM> forms a slot opening <NUM> receiving for example a LED indicating at least an ON state of the device <NUM>. It can also indicate for example a battery law state, an error state, etc..

The housing <NUM> delimits an internal space of the device <NUM> receiving various elements designed to carry out different functionalities of the device <NUM>. This internal space can for example receive a battery for powering the device <NUM>, a controller <NUM> for controlling the operation of the device <NUM>, a heating chamber <NUM> for heating the aerosol generating substrate <NUM> and at least two heating elements 47A, 47B for heating the heating chamber <NUM>. In some embodiments, the housing <NUM> may further comprise at least one temperature sensor. This temperature sensor can for example generate temperature measurements relative to the temperature of the least one heating element 47A, 47B and/or of the aerosol generating substrate <NUM> and/or of the aerosol generated by the aerosol generating substrate.

<FIG> shows in more detail the mouthpiece <NUM>. In reference to this <FIG>, the mouthpiece <NUM> is delimited by an internal surface <NUM> intended to face the insertion opening <NUM> while assembling the mouthpiece <NUM> with the housing <NUM>, and an external surface <NUM> intended to form with the housing <NUM> at least one side wall <NUM> of the device <NUM>. An external border <NUM> of the internal surface <NUM> is designed to be in a tight contact with a part of an internal border of the insertion opening <NUM> to fix the mouthpiece <NUM> inside the insertion opening <NUM>. The external surface <NUM> has an appropriate shape to be in contact with the user's mouth and/or lips. Each side of the external surface <NUM> can be formed as an extension of the corresponding side of the housing to form an almost continuous side wall <NUM> of the device <NUM>. Particularly, in this case, a discontinuity can be formed in the transition zone between the mouthpiece <NUM> and the housing <NUM>.

The mouthpiece <NUM> is crossed by a through-hole <NUM> extending along the device axis Y between a recess portion <NUM> and a flow outlet <NUM>. Particularly, the through-hole <NUM> is designed to receive the mouthpiece part <NUM> of the aerosol generating substrate <NUM> so as the substrate axis X coincides with the device axis Y. Thus, the through-hole <NUM> has the same cross-sectional shape as the aerosol generating substrate <NUM> and defines internal dimensions slightly greater than the external dimensions of the mouthpiece part <NUM> of the aerosol generating substrate <NUM>. Particularly, in the example of the figures, the through-hole <NUM> defines a rectangular cross-section to be able to receive the mouthpiece part <NUM> of the aerosol generating substrate <NUM> shown on <FIG>. In some embodiments, the through-hole <NUM> may have variable cross-sectional dimensions. For example, the through-hole <NUM> can have gradually decreasing cross-sectional dimensions (notably the width) from the recess portion <NUM> to the flow outlet <NUM>. Additionally, the through-hole <NUM> and the mouthpiece part <NUM> of the aerosol generating substrate <NUM> can have the same length measured respectfully according to the device axis Y and the substrate axis X. According to another embodiment, the length of the mouthpiece part <NUM> of the aerosol generating substrate <NUM> can be less than the length of the through-hole <NUM> so as the mouth end <NUM> of the aerosol generating substrate <NUM> can be flushed at the flow outlet <NUM>.

The recess portion <NUM> corresponds to a cavity formed in both internal and external surfaces <NUM>, <NUM> of the mouthpiece <NUM>. This cavity can be formed by a first opening extending on the internal surface <NUM> on one side of the through-hole <NUM> from the border <NUM> to this through-hole <NUM> and a second opening extending on the external surface <NUM> from the border following d% of the length of the mouthpiece <NUM> measured according to the device axis Y. The value d can be less than <NUM>, advantageously less than <NUM> and more advantageously less than <NUM>. Thus, when the mouthpiece <NUM> is inserted in the insertion opening <NUM>, the recess portion <NUM> forms an opening <NUM> forming a flow inlet <NUM> as shown on <FIG>. In other words, the flow inlet <NUM> is formed on a side wall <NUM> of the device <NUM> in a transition zone between the mouthpiece <NUM> and the housing <NUM>.

In the embodiment where the aerosol generating substrate <NUM> comprises the venting holes <NUM>, at least some of these venting holes <NUM> are arranged to face the flow inlet <NUM>.

According to another embodiment (not shown), a flow inlet is formed at any other wall of the device <NUM>. It can for example be formed at the wall opposite to the mouthpiece <NUM>.

In reference to <FIG>, the heating chamber <NUM> forms a cup-shaped heating chamber extending along the device axis Y between an open end <NUM> and a sealed end <NUM>. The heating chamber <NUM> is designed to receive the heater part <NUM> of the aerosol generating substrate <NUM>. For this purpose, the heating chamber <NUM> defines substantially the same cross-sectional shape as the aerosol generating substrate <NUM>. Particularly, in the example of the figures, the heating chamber <NUM> defines a rectangular cross-sectional shape with two parallel chamber lateral walls 73A, 73B and two parallel chamber contact walls 74A, 74B. Each chamber contact wall 74A, 74B is for example at least <NUM> times, advantageously <NUM> times and more advantageously <NUM> times, wider than each chamber lateral wall 73A, 73B.

Each heating wall 74A, 74B may be for example rigidly fixed to each chamber lateral wall 73A, 73B so as to define the rectangular cross-sectional shape, and in particular to form a cup shape of the heating chamber <NUM>.

The heating walls 74A, 74B may be arranged opposite and in parallel one to another, in particular facing each other for example in the absence of the aerosol forming substrate <NUM>.

According to embodiments, each heating element 47A, 47B may be parallel to a respective heating wall 74A, 74B of the heating chamber <NUM>. For example, each heating element 47A, 47B may be arranged between the aerosol forming substrate <NUM> and the corresponding heating wall 74A, 74B or be integrate inside the corresponding heating wall 74A, 74B.

The heating chamber <NUM> also defines a distal wall <NUM> arranged perpendicularly to the device axis Y and sealing the sealed end <NUM>. Particularly, the distal wall <NUM> is adjacent to each of the walls 73A, 73B, 74A, 74B so as to seal the chamber at the sealed end <NUM> and thus, form a cup shape of the chamber opening at the open end <NUM>. Particularly, in this case, the only air permeable opening of the chamber <NUM> is formed at the open end <NUM>. According to another embodiment (not shown), the distal wall <NUM> defines an opening suitable for air entering inside the chamber <NUM> and notably inside the aerosol forming substrate <NUM>. Each of the walls 73A, 73B, 74A, 74B, <NUM> can be made from a thermally conductive material like a metal, notably a stainless steel. Additionally, at least some of the walls 73A, 73B, 74A, 74B, <NUM> or all of these walls can form one single piece.

The internal dimensions of the heating chamber <NUM> are defined by the length L3 measured according the device axis Y, the width W3 measured as the distance between the chamber lateral walls 73A, 73B and the depth D3 measured as the distance between the chamber contact walls 74A, 74B. These internal dimensions L3, W3, D3 are chosen basing on the external dimensions L2, W, D of the heater part <NUM> of the aerosol generating substrate <NUM>.

Particularly, the depth D3 of the heating chamber <NUM> is chosen slightly greater than the depth D of the aerosol generating substrate <NUM> or substantially equal to this depth D. In this case, the substrate contact walls 14A, 14B can be in contact with the chamber contact walls 74A, 74B and notably with contact surfaces of these walls 74A, 74B, when the heater part <NUM> of the of the aerosol generating substrate <NUM> is received inside the heating chamber <NUM>. Advantageously, in this case, the chamber contact walls 74A, 74B and notably their contact surfaces, are in a tight contact with the substrate contact walls 14A, 14B. In some embodiments, the depth D3 of the heating chamber <NUM> can be even slightly less than the normal depth D of the aerosol generating substrate <NUM>. In this case, the heating chamber <NUM> and/or the mouthpiece <NUM> is(are) configured to compress the heater part <NUM> of the aerosol generating substrate <NUM> by exerting force on the substrate contact walls 14A, 14B. This makes it possible to improve the tight contact between the corresponding contact walls of the heating chamber <NUM> and the substrate <NUM> and thus, to improve heat transfer between these walls.

For example, each substrate contact wall 14A, 14B consists of a first surface area of this wall of the heater part <NUM> and a second surface area of this wall of the mouthpiece part <NUM>. According to some embodiments, each chamber contact wall 74A, 74B presents an area equal to or larger than the corresponding surface area of the heater part <NUM> of the aerosol generating substrate <NUM>, e.g. the first surface area of the substrate contact wall 14A, 14B. This is for example visible in <FIG>. In particular, each chamber contact wall 74A, 74B extends laterally, i.e. in a direction perpendicular to device axis Y, over edges of the surface area of the heater part <NUM>.

The width W3 of the heating chamber <NUM> is chosen so as at least one pair of facing lateral walls 73A, 13A or 73B, 13B of the heating chamber <NUM> and the aerosol generating substrate <NUM> forms an airflow channel between them. Advantageously, the width W3 of the heating chamber <NUM> is chosen so as each pair of facing lateral walls 73A, 13A or 73B, 13B of the heating chamber <NUM> and the aerosol generating substrate <NUM> forms an airflow channel between them. In other words, the width W3 of the heating chamber <NUM> is chosen so as to form a distance d1 between each pair of facing lateral walls 73A, 13A or 73B, 13B as it is shown on <FIG>. Particularly, in the example of this Figure, W3=W+2d1. The distance d1 may for example be chosen substantially equal to the depth D3 of the heating chamber <NUM>. In this case, when the heater part <NUM> of the aerosol generating substrate <NUM> is inserted in the heating chamber <NUM>, an airflow channel of substantially square cross-section is formed along the device axis Y on either lateral side of the aerosol generating substrate <NUM>. Of course, the distance d1 may be chosen equal to any other value depending on the flow rate required inside the aerosol generating substrate <NUM> while its heating. Additionally, in this case, the distal wall <NUM> of the heating chamber <NUM> can form a rib or any other stopping mean preventing contact of the abutting end <NUM> of the aerosol generating substrate <NUM> with the distal wall <NUM> of the heating chamber <NUM>. In other words, this stopping mean is configured to create an airflow channel connecting each of the airflow channels formed between the chamber lateral walls 73A, 73B and the aerosol generating substrate <NUM>, with each airflow channel formed inside the aerosol generating substrate <NUM>.

According to another embodiment (not-shown), no airflow channel between the pairs of facing lateral walls 73A, 13A or 73B, 13B of the heating chamber <NUM> and the aerosol generating substrate <NUM> is formed. In this case, these pairs of lateral walls 73A, 13A or 73B, 13B may be in contact, advantageously in tight contact between them. This embodiment is notably suitable when the distal wall <NUM> or any other wall of the heating chamber <NUM> forms an opening suitable for air entering.

As shown on <FIG> and <FIG>, each heating element 47A, 47B is arranged in contact with one of the chamber contact walls 74A, 74B outside of the heating chamber <NUM>. Particularly, in the example of these Figures, the heating element 47A is arranged adjacent to an outer surface of the chamber contact wall 74A and the heating element 47B is arranged adjacent to an outer surface of the chamber contact wall 47A. Thus, the chamber contact walls 74A, 74B are also called heating walls 74A, 74B since they ensure heat transfer from the heating elements 47A, 47B to the aerosol generating substrate <NUM>. Each heating element 47A, 47B may comprise a polyimide film heater extending along substantially the total area of said outer surface of the corresponding heating wall 74A, 74B or only along a part of this surface. In this last case, said part may form a width substantially equal to the width W of the aerosol generating substrate <NUM>. According to some embodiments, the aerosol generating device <NUM> further comprises an insulator arranged between each heating element 47A, 47B and an inner surface of the housing <NUM>. The same insulator may also be arranged between an outer surface of each of the chamber lateral walls 73A, 73B and the inner surface of the housing <NUM>.

The controller <NUM> is configured to control the operation of the aerosol generating device <NUM>. For this purpose, the controller <NUM> may present at least one software and/or hardware component able to control the operation of the aerosol generating device <NUM> and notably, the operation of the heating elements 47A, 47B as it will be explained below in further detail. When the controller <NUM> presents at least one software component, this component can be carried out using an appropriate processor and memory comprised in the device <NUM>. When the controller <NUM> presents at least one hardware component, such a component may present a programmable unit such for example Field Programmable Gate Arrays (known as "FPGA").

Particularly, the controller <NUM> may be configured to operate separately the operation of each heating element 47A, 47B, according to a heating profile chosen among a predetermined group of heating profiles. The corresponding heating profile may be chosen according to a mode of operation of the device <NUM> and/or according to at least some external/internal parameters relative to the operation of the device <NUM>.

The operation mode of the device can for example correspond to a pre-heating mode or a floating mode. During the pre-heating mode, the aerosol generating substrate <NUM> is heated from an ambient temperature to a temperature making it possible to generate aerosol. During the floating mode, the aerosol generating substrate <NUM> is heated to generate aerosol further to user puffs. Thus, the floating mode corresponds to a normal operation of the aerosol generating device <NUM> during a vaping session. The parameters relative to the operation of the device <NUM> may correspond to temperature measurements provided by a temperature sensor arranged for example inside the housing <NUM> as previously explained. As mentioned above, these temperature measurements may be relative to the temperature of at least one or both heating elements 47A, 47B, to the temperature of the aerosol generating substrate <NUM> or to the temperature of the produced aerosol.

The controller <NUM> may for example be configured to choose a first heating profile during the pre-heating mode of operation of the device <NUM> and a second heating profile during at least at the beginning of the floating mode of operation of the device <NUM>. For example, the first heating profile may comprise activation of both heating elements 47A, 47B until reaching a first target temperature and the second heating profile comprising activation of one of the heating elements (for example of the heating element 47A) until reaching a second target temperature. The second heating profile may further comprise activation/deactivation of the heating element 47A to maintain the second target temperature. In some embodiments, the first target temperature and the second target temperature may be equal to a same value, said value being comprised between <NUM> and <NUM>, advantageously between <NUM> and <NUM>. Advantageously, the value can correspond to the temperature of the aerosol generating substrate <NUM> making it possible to generate aerosol while user puffing, without burning the substrate.

In some embodiments, after having operated the heating elements 47A, 47B according to the second heating profile, the controller <NUM> is configured to operate these elements according to still another heating profile, chosen for example according to temperature measurements provided by the temperature sensor and/or according to predetermined time periods/frequencies. Such a heating profile may be chosen in the group comprising at least:.

Other heating profiles are also possible. Particularly, a heating profile may correspond to any combination of the pre-cited heating profiles. Moreover, in case of more than two heating elements, the heating profiles may be more complex and include activation of at least a first group of heating elements and deactivation of at least a second group of heating elements, according to the mode of operation of the device and/or external/internal parameters such as temperature measurements. Additionally, it is clear that only certain (or only one) of the third to sixth heating profiles may be carried out during a vaping session, according to any suitable order.

The operation of the aerosol generating device <NUM> will now be described. Initially, it is considered that the aerosol generating substrate <NUM> is extracted from the device <NUM>. In order to insert it, the user first takes off the mouthpiece <NUM> from the housing <NUM>. Then, the user inserts the heater part <NUM> of the aerosol generating substrate <NUM> into the heating chamber <NUM> until the abutting end <NUM> of the substrate <NUM> abuts against the stopping mean of the distal wall <NUM>. Then, the user fixes the mouthpiece <NUM> on the housing <NUM> by sliding the mouthpiece part <NUM> of the aerosol generating substrate <NUM> inside the through-hole <NUM> of the mouthpiece <NUM> and by inserting the mouthpiece <NUM> in the insertion opening <NUM> of the housing <NUM>.

Then, the user can activate the operation of the aerosol generating device <NUM> by actuating for example an ON button or by performing a puff. This creates an airflow in an airflow path formed inside the device between the flow inlet <NUM> and the flow outlet <NUM> as it is shown on <FIG>.

Upon activation of the aerosol generating device <NUM>, the controller <NUM> starts the pre-heating mode of the operation and operates the heating elements 47A, 47B according to the first heating profile, as explained above. When the first target temperature is achieved, the controller <NUM> proceeds with the floating mode of operation of the device <NUM> and operates the heating elements 47A, 47B according to the second heating profile. After, the controller <NUM> may operate these heating elements according to at least another heating profile, as previously explained.

As visible in <FIG>, the heater part <NUM> of the aerosol generating substrate <NUM> may have for example a flat-plate shape with slotted grooves on both opposite surfaces.

<FIG> shows an aerosol generating device <NUM> according to a second embodiment. This aerosol generating device <NUM> is similar to the aerosol generating device <NUM> and notably, is configured to operate with the same aerosol generating substrate <NUM> shown on <FIG>.

The aerosol generating device <NUM> according to the second embodiment also comprises a device body <NUM> defining at least one side wall <NUM> of the device <NUM> and comprising a mouthpiece <NUM> and a housing <NUM> having similar external shapes as respectfully the mouthpiece <NUM> and the housing <NUM> explained before in relation with the first embodiment. However, according to the second embodiment, the mouthpiece <NUM> and the housing <NUM> form a single piece. In this case, the aerosol generating substrate can for example be loaded directly from an opening <NUM> of the mouthpiece <NUM>. This opening <NUM> also forms a flow outlet <NUM> similar to the flow outlet <NUM> explained before. The aerosol generating substrate <NUM> can be extracted from the same opening <NUM> using for example an internal extracting mechanism which can be actuated by an actuator <NUM> arranged on the side wall <NUM>.

The or each side wall <NUM> has for example a smooth external surface and defines a transition zone between the mouthpiece <NUM> and the housing <NUM>. Furthermore, as in the previous case, the transition zone defines an opening <NUM> forming a flow inlet <NUM>.

The interior part of the aerosol generating device <NUM> is similar to the interior part of the aerosol generating device <NUM> explained above. Particularly, the aerosol generating device <NUM> comprises the same heating chamber as the heating chamber <NUM> explained before and forming at least two heating walls. As in the previous case, a heating element is attached on the heating wall and can be controlled separately from each other heating element by a controller similar to the controller <NUM> explained above.

The operation of the aerosol generating device <NUM> is also similar to the operation of the aerosol generating device <NUM> explained above. The unique difference consists in the way of loading/extracting of the aerosol generating substrate <NUM>.

<FIG> shows an aerosol generating device <NUM> according to a third embodiment. This aerosol generating device <NUM> is similar to the aerosol generating device <NUM> according to the second embodiment and notably, is configured to operate with the same aerosol generating substrate <NUM> shown on <FIG>.

The aerosol generating device <NUM> according to the third embodiment also comprises a device body <NUM> defining at least one side wall <NUM> of the device <NUM>. Contrary to the previous embodiments, the device body <NUM> according to the third embodiment does not define a mouthpiece. As it is shown on <FIG>, a mouthpiece is formed by at least a part of the mouthpiece part <NUM> of the aerosol generating substrate <NUM>.

Particularly, according to this embodiment, the device body <NUM> forms an insertion opening <NUM> extending perpendicularly to the device axis Y at one of the ends of the device body <NUM>. As in the second embodiment, the opening <NUM> is suitable to receive at least the heater part <NUM> of the aerosol generating substrate <NUM>. Particularly, as in the previous cases, the opening <NUM> communicates with a heating chamber arranged inside the device body <NUM>. This heating chamber is similar to the heating chamber explained above and notably, is adapted to receive the heater part <NUM> of the aerosol generating substrate <NUM>. Additionally, as in the previous cases, at least two heating elements configured to be operated separately by a controller are provided.

Contrary to the previous cases, at least a part of the mouthpiece part <NUM> of the aerosol generating substrate <NUM> protrudes from the opening <NUM> forming thus a mouthpiece. In other words, this protruding part of the aerosol generating substrate <NUM> is designed to be in contact with the user's lips and mouth while using the device <NUM> and forms a flow outlet <NUM>.

As in the previous cases, a flow inlet <NUM> is formed on the side wall <NUM> of the device body <NUM>. This flow inlet <NUM> is in a fluid communication with each of the airflow channels formed between the lateral walls of the heating chamber and the aerosol generating substrate <NUM>. Additionally, as in the previous cases, the flow is forced inside the chamber to follow a "U" turn to flow inside the aerosol generating substrate <NUM> until the flow outlet <NUM>.

When the aerosol generating substrate <NUM> comprises venting holes <NUM>, these venting holes <NUM> may be arranged on the protruding part of the mouthpiece part <NUM> of the substrate <NUM> as it is shown on <FIG>. According to another example, the venting holes <NUM> are arranged on the part of the mouthpiece part <NUM> of the substrate <NUM> which is received inside the device body <NUM>, advantageously to face the flow inlet <NUM> as in the second embodiment.

As in the second embodiment, an actuator <NUM> may be arranged on the side wall <NUM> of the device <NUM> to facilitate the extraction of the aerosol generating substrate <NUM>. According to another example, no actuator is provided on the side wall and the substrate <NUM> is extracted by pulling its protruding part.

Claim 1:
An aerosol generating device (<NUM>; <NUM>; <NUM>) configured to operate with an aerosol generating substrate (<NUM>) and comprising:
- a device body (<NUM>; <NUM>; <NUM>) extending along a device axis (Y);
- a cup-shaped heating chamber (<NUM>) defining an open end (<NUM>) and at least two heating walls (74A, 74B) arranged opposite and in parallel one to another, the cup-shaped heating chamber (<NUM>) being configured to receive a heater part (<NUM>) of the aerosol generating substrate (<NUM>) through the open end (<NUM>);
- two heating elements (47A, 47B), each heating element (47A, 47B) being adjacent and parallel to a respective heating wall (74A, 74B) of the heating chamber (<NUM>);
- a controller (<NUM>) configured to operate separately each heating element (47A, 47B) with the same aerosol generating substrate (<NUM>), according to a heating profile chosen among a predetermined group of heating profiles,
characterized in that said group of heating profiles comprising at least:
a) a first heating profile comprising activation of both heating elements (47A, 47B) until reaching a first target temperature;
b) a second heating profile comprising activation of one of the heating elements (47A, 47B) until reaching a second target temperature,
the controller (<NUM>) being configured to choose the first heating profile during a pre-heating mode of operation of the device (<NUM>; <NUM>; <NUM>) and the second heating profile during a floating mode of operation of the device (<NUM>; <NUM>; <NUM>).