Aerosol-generating device configured to operate with an aerosol-generating substrate

Abstract

The present invention relates to an aerosol generating device configured to operate with a flat tobacco article (12) and including a planar heating chamber (50) extending along a device longitudinal axis (X'). The heating chamber (50) is configured to receive at least a tobacco portion (15) of the flat tobacco article (12) and includes a continuous heating surface (72A) configured to contact a first outer surface of the tobacco portion (15). The area of ​​the heating surface (72A) is comprised between 35% and 99% of the area of ​​the first outer surface of the tobacco portion (15).

Description

[Technical Field]

[0001] The present disclosure relates to an aerosol-generating device configured to operate with an aerosol-generating substrate.

[0002] In particular, the aerosol-generating device according to the present invention is configured to operate with tobacco articles, e.g., flat tobacco articles, that include, e.g., a solid substrate that is capable of forming an aerosol when heated. Thus, these types of aerosol-generating devices, also known as non-combustion heating devices, are adapted to heat, by conduction, convection, and / or radiation, rather than burning, the substrate, to generate an aerosol for inhalation. [Background technology]

[0003] The popularity and use of risk-reducing or risk-modifying devices (also known as vaporizers) has grown rapidly in recent years as aids to assist regular smokers who wish to quit smoking traditional tobacco products such as cigarettes, cigars, cigarillos, and cigarettes. A variety of devices and systems are available that heat or warm a vaporizable substance, as opposed to burning tobacco in traditional tobacco products.

[0004] Commonly available risk reduction or risk modification devices are substrate-heated aerosol generating devices or non-combustion-heated devices. These types of devices typically generate aerosol or vapor by heating an aerosol substrate containing moist tobacco or other suitable vaporizable material, typically to temperatures ranging from 150°C to 350°C. By heating, rather than burning or combusting, the aerosol substrate releases an aerosol containing the ingredients desired by the user but without the toxic and carcinogenic by-products of combustion and burning. Furthermore, aerosols produced by heating tobacco or other vaporizable material typically do not contain the burnt or bitter tastes associated with combustion and burning, which can be unpleasant to users. Thus, the substrate does not require sugars and other additives typically added to such materials to make the smoke and / or vapor more palatable to users.

[0005] Aerosol generating devices generally include at least one heating plate intended to heat the aerosol substrate. During operation, heat transfer occurs between the heating plate and the aerosol substrate. However, the heating plate has the disadvantage of consuming a large amount of energy to raise the temperature and thus heat the tobacco article to the target temperature. This limits the autonomy of the aerosol generating device, and users must frequently recharge or replace the device's electric battery. Summary of the Invention [Problem to be solved by the invention]

[0006] One object of the present invention is to provide an aerosol generating device that requires less energy to heat vaporizable material to vaporize it from the tobacco article. [Means for solving the problem]

[0007] To this end, the present invention relates to an aerosol generating device configured to operate with a flat tobacco article and including a planar heating chamber extending along a longitudinal axis of the device, wherein the flat tobacco article extends along the article longitudinal axis and includes a tobacco portion and a non-tobacco portion arranged consecutively along the article longitudinal axis, the tobacco portion defining a first outer surface and a second outer surface opposite the first outer surface, the heating chamber configured to receive at least the tobacco portion of the flat tobacco article and including a first heating plate partially forming a wall of the heating chamber, the first heating plate including a continuous first heating surface configured to contact the first outer surface of the tobacco portion, the area of ​​the heating surface being between 35% and 99% of the area of ​​the first outer surface of the tobacco portion.

[0008] The inventors have surprisingly found that the heating surface in contact with the outer surface of the tobacco portion can be smaller than said outer surface while still providing sufficient heat to vaporize the vaporizable material.

[0009] These features make it possible to provide an aerosol generating device that requires less energy to heat the vaporizable material to evaporate from the tobacco article while optimally heating the tobacco article. In particular, the first heating surface, due to its small size, allows the tobacco article to be heated quickly to a predetermined temperature and maintained at or near this predetermined temperature with less energy than a larger heating plate.

[0010] Additionally, the first heating surface achieves uniform heating throughout the vaping session, enhancing the user's experience.

[0011] Furthermore, by providing a heating surface that is smaller than the outer surface of the tobacco portion that it contacts, it is possible to keep the bottom of the tobacco portion from contacting the heating surface, reducing steam that forms at the bottom end of the chamber that could otherwise leak, condense, and then require cleaning by the user.

[0012] According to some embodiments, the area of ​​the first heating surface is comprised between 40% and 95%, preferably between 40% and 90%, more preferably between 45% and 85%, advantageously between 50% and 80%, advantageously between 50% and 75% of the area of ​​the first outer surface of the tobacco portion.

[0013] These features allow the heating of the tobacco portion to be further optimized in terms of energy.

[0014] According to some embodiments, the heating chamber further includes a second heating surface configured to contact a second exterior surface of the tobacco portion.

[0015] Having a second heating surface allows for more uniform heating of the tobacco article throughout the vaping session by allowing for greater heat penetration into the tobacco article, thereby allowing for more vapor to be generated compared to having only a first heating surface.

[0016] As a result, the combination of two heating surfaces, at least one of which is smaller than the outer surface of the tobacco portion, allows for optimized heating of the flat tobacco article while requiring less energy compared to previous aerosol generating devices.

[0017] Furthermore, each heated surface may exhibit different sizes, materials, and / or physical properties to ensure better operation of the aerosol generating device. For example, one heated surface may heat up more quickly, allowing for a rapid preheating phase, while the other heated surface may accumulate thermal energy and heat more uniformly.

[0018] According to some embodiments, the area of ​​the second heating surface is comprised between 35% and 99%, preferably between 40% and 95%, preferably between 40% and 90%, more preferably between 45% and 85%, advantageously between 50% and 80%, advantageously between 50% and 75% of the area of ​​the second outer surface of the tobacco portion.

[0019] These features also reduce the energy required to heat the second heated surface to a predetermined temperature, increasing the autonomy of the aerosol generating device as less energy is required than in previous aerosol generating devices.

[0020] According to some embodiments, the first and second heating surfaces form the same dimensions and are aligned opposite each other according to an up-down axis perpendicular to each of the surfaces.

[0021] These features allow the tobacco portion to be sandwiched between the heating surfaces and heated evenly from both sides, achieving greater heat penetration into the tobacco article, thereby allowing for more vapor to be generated more quickly.

[0022] According to some embodiments, the first and second heating surfaces are positioned opposite each other along an up-down axis that is perpendicular to each of the heating surfaces, and the heating surfaces are offset from each other along an offset axis that is perpendicular to the up-down axis.

[0023] It is thus possible to better control the heating of the tobacco portion performed by the heating surface. In order to optimize the heating of the tobacco portion, it is possible to create different heating zones within the tobacco portion depending on the position of the tobacco portion relative to the heating surface.

[0024] According to some embodiments, the first heated surface and the second heated surface are operated at different target temperatures.

[0025] These features make it possible to control the heating of the tobacco portion performed by the different heating surfaces using different heating profiles, each of which can be selected, for example, based on the characteristics of the heating surface, and thus the heating of the tobacco portion can be optimized for different heating plates.

[0026] The temperature to which each surface is heated can also be adjusted depending on the position of the heated surface relative to the tobacco portion: for example, the heated surface facing the abutment of the tobacco portion may be heated to a lower temperature than the heated surface closer to the mouthpiece to reduce steam forming at the bottom end of the chamber that would otherwise leak, condense, and then require cleaning by the user.

[0027] According to some embodiments, the or each heating surface forms a length, measured along the device longitudinal axis, that is comprised between 60% and 99%, preferably between 70% and 95%, more preferably between 75% and 90%, of the length of the corresponding outer surface of the tobacco portion, measured along the article longitudinal axis.

[0028] According to some embodiments, the or each heating surface defines a width measured along a device transverse axis perpendicular to the device longitudinal axis that is comprised between 60% and 99%, preferably between 70% and 95%, more preferably between 75% and 90% of the width of the corresponding outer surface of the tobacco portion measured along an article transverse axis perpendicular to the article longitudinal axis.

[0029] These features ensure sufficient heating of the tobacco portion.

[0030] According to some embodiments, the heating chamber includes a first plate partially forming a wall of the heating chamber, the first heating plate including a first heating surface, and the heating chamber preferably includes a second heating plate including a second heating surface, the first heating plate and the second heating plate partially forming opposite walls of the heating chamber.

[0031] According to some embodiments, the or each heating plate comprises a planar substrate and a resistive heating track embedded in or mounted on the planar substrate.

[0032] According to some embodiments, the planar substrate of the or each heating plate comprises a hard material, preferably selected between ceramic and metal.

[0033] Both metals and ceramics exhibit favorable physical properties to ensure the operation of the aerosol generating device according to the present invention. For example, ceramics are known to exhibit a higher heat capacity value than metals. While metallic heating plates can heat up more quickly, ceramic heating plates can store more heat energy and heat the tobacco portion more uniformly.

[0034] The heating plates can be made of the same material or different materials depending on the thermal properties required.

[0035] Each heating plate may present a homogenous body made from the same material, such as metal or ceramic.

[0036] For example, at least one heating plate may be made of an oxide ceramic material, such as Al2O3, zirconia, silicon nitride, or aluminum nitride.

[0037] In a variant, the planar substrate of the or each heating plate comprises a flexible, heat-resistant resin, the resin preferably being chosen between polyimide and fluororesin.

[0038] In a variant, the heating chamber includes a long strip of flexible heater that includes two separate track patterns wrapped around the heating chamber such that the two patterns form a first heating surface and a second heating surface, respectively.

[0039] According to some embodiments, the or each heating surface is associated with a unique heating element.

[0040] In other words, each plate is made from a single piece and provides a continuous heating surface, which allows for more uniform heating of the outer surface of the tobacco portion compared to heating plates made from multiple heating elements.

[0041] The invention and its advantages will be better understood from reading the following description, given purely by way of non-limiting example and made with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0042] [Figure 1] 1 is a perspective view of an aerosol generation assembly including an aerosol generation device according to the present invention and a tobacco article usable with the aerosol generation device. [Figure 2] FIG. 2 is a perspective view of the tobacco article of FIG. 1. [Figure 3] 3 is a partial cross-sectional view of the aerosol generation assembly of FIG. 1 taken along plane III. [Figure 4] 2 is a partial perspective view of the aerosol generation assembly of FIG. 1, showing only the tobacco article and the first heating plate of the aerosol generation device. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0043] Before the present invention is described, it is to be understood that the invention is not limited to the details of construction set forth in the following description. It will be apparent to one skilled in the art having the benefit of this disclosure that the invention is capable of other embodiments and of being practiced or carried out in various ways.

[0044] In the following, the expression "substantially equal" is understood to mean equal to ±10%, preferably ±5%.

[0045] As used herein, the terms "aerosol-generating device" or "device" may include a vaping device for delivering an aerosol, including an aerosol for vaping, to a user using a heater element, as described in more detail below. The device may be portable. "Portable" may refer to a device used while held by a user. The device may be adapted to generate a variable amount of aerosol (as opposed to a fixed amount of aerosol), for example, by activating a heater element for a variable amount of time. The variable amount of aerosol may be controlled by a trigger. The trigger may be user-activated, such as a vaping button and / or an inhalation sensor. The inhalation sensor may be sensitive to inhalation intensity and duration, allowing for the provision of a variable amount of vapor (to mimic the smoking effect of a conventional combustible smoking article, such as a cigarette, cigar, or pipe). The device may include a temperature regulation control for driving the temperature of the heater and / or heated aerosol-generating material (aerosol precursor) to a specified target temperature and then maintaining that temperature at a target temperature that enables efficient generation of aerosol.

[0046] As used herein, the term "aerosol" may include a suspension of vaporizable material as one or more of solid particles, liquid droplets, and gas. The suspension may be present in a gas, including air. Aerosol herein may generally refer to / include a vapor. The aerosol may include one or more components of the vaporizable material.

[0047] As used herein, the terms "vaporizable material" or "precursor" may refer to smokable material, which may include, for example, nicotine or tobacco and an aerosol-forming agent. The tobacco may take the form of various materials, such as cut tobacco, granulated tobacco, tobacco leaf, and / or reconstituted tobacco. Suitable aerosol-forming agents include polyols (sorbitol, glycerol, and glycols (such as propylene glycol or triethylene glycol)), non-polyols (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 include at least one of a gelling agent, a binder, a stabilizer, and a humectant.

[0048] 1 shows an aerosol-generating assembly 10 including an aerosol-generating device 11 and a tobacco article 12. The aerosol-generating device 11 is intended to operate with a tobacco article 12, which is shown in more detail in FIG.

[0049] In the example of Fig. 2, the tobacco article 12 is, for example, a flat tobacco article that extends along the article longitudinal axis X and presents a flat rectangular parallelepiped shape with outer dimensions L12 x W12 x D12. In a typical example, the length L12 of the article 12 along the article longitudinal axis X is substantially equal to 33 mm, while the width W12 and depth D12 of the article 12 are substantially equal to 12 mm and 1.2 mm, respectively. According to another example, the values ​​L12, W12, and D12 can be selected, for example, within a range of ±40%. The depth D12 of the tobacco article 12 is formed by a pair of parallel walls 13A, 13B, hereinafter referred to as narrow walls 13A, 13B, and the width W12 of the tobacco article 12 is formed by a pair of parallel walls 14A, 14B, hereinafter referred to as wide walls 14A, 14B. In some embodiments, the edges between the wide walls 14A, 14B and the narrow walls 13A, 13B may be rounded. According to other embodiments of the present invention, the tobacco article 12 may have any other suitable flat shape and / or overall dimensions. According to still other embodiments, the tobacco article 12 may have any other suitable shape, such as a stick shape. According to some embodiments, the wide walls 14A, 14B may be corrugated.

[0050] The tobacco article 12 includes a tobacco portion 15 and a non-tobacco portion 16, also referred to as a mouthpiece portion 16, disposed along the article longitudinal axis X. The tobacco portion 15 may, for example, be slightly longer than the non-tobacco portion 16. The tobacco portion 15 is formed by parallel walls 15A, 15B that are part of the broad walls 14A, 14B of the tobacco article 12. For example, the length L15 of the tobacco portion 15 along the article longitudinal axis X may be substantially equal to 18 mm. The width W15 of the tobacco portion 15 is equal to the width W12 of the tobacco article 12. The length L16 of the mouthpiece portion 16 along the article longitudinal axis X may be substantially equal to 15 mm. The tobacco portion 15 defines an abutting end 18 of the article 12, and the non-tobacco portion 16 defines a mouth end 20 of the article 12.

[0051] The tobacco portion 15 and the non-tobacco portion 16 may be secured together by a wrapper 21 extending about the longitudinal axis X of the article. The wrapper 21 forms the narrow walls 13A, 13B and the broad walls 14A, 14B of the tobacco article 12. In some embodiments, the wrapper 21 is formed from the same wrapping sheet. In some other embodiments, the wrapper 21 is formed by separate wrapping sheets that separately wrap the portions 15, 16 and secure them together by any other suitable means. The wrapper 21 may comprise, for example, paper and / or a nonwoven fabric and / or aluminum foil. The wrapper 21 may be porous or air impermeable and form a plurality of air flow passages extending inside the article 12 between the abutment end 18 and the mouth end 20.

[0052] The non-tobacco portion 16 includes a core 27 intended to act as, for example, a cooler to slightly cool the vapor before it is inhaled by the user. The core 27 may for this purpose include, for example, corrugated paper. Advantageously, the core 27 is arranged inside the non-tobacco portion 16 so as to be in total contact with the inner surface of the wrapper 21 that defines the non-tobacco portion 16.

[0053] Tobacco portion 15 contains vaporizable material and is intended to be heated by a heating chamber, as will be explained in more detail below.

[0054] The tobacco portion 15 defines a first outer surface 30 and a second outer surface 32 opposite the first outer surface 30. In the example of Figure 2, the first outer surface 30 and the second outer surface 32 correspond to the outer surfaces of the broad walls 14A, 14B.

[0055] 1, the aerosol generating device 11 includes a device body 40 and a mouthpiece 42, which extend along a device axis X'. According to the example described below, the mouthpiece 42 and the device body 40 form two different parts. In particular, according to this example, the mouthpiece 42 is designed to be fixed to a fixed end of the device body 40.

[0056] As shown in FIG. 3 , the mouthpiece 42 includes a central portion 43 and a peripheral portion 44 extending around the central portion 43. The peripheral portion 44 may, for example, define a collar that partially covers the outer surface of the device body 40 when the mouthpiece 42 is secured to the fixed end of the device body 40. For example, the peripheral portion 44 may be designed to cooperate with a gasket 45 disposed on the fixed end of the device body 40 to seal a space formed between the peripheral portion 44 and the outer surface of the device body 40. The central portion 43 of the mouthpiece 42 defines a through-hole 46 adapted to at least partially receive the tobacco article 12. Specifically, the through-hole 46 may be adapted to receive at least a portion of the non-tobacco portion 16 of the tobacco article 12, as shown in FIG. 3 . Advantageously, the through-hole 46 may be adapted to securely fit the non-tobacco portion 16 of the tobacco article 12 to prevent or minimize flow leakage between a wall defining the through-hole 46 and the outer surface of the tobacco article 12. In some embodiments, the tobacco article 12 can be retained within the through-hole 46 by, for example, friction. In this case, for example, the mouthpiece portion 16 of the tobacco article 12 can be inserted into the through-hole 46 first, with both elements then secured to the fixed end of the device body 40. As also shown in FIG. 3 , an interior volume 47 is formed between the inner surface 48 of the mouthpiece 42 and the fixed end of the device body 40. This interior volume 47 is traversed by the tobacco article 12 as it is inserted into the device body 40. For example, the tobacco article 12 can divide the interior volume 47 into two symmetrical portions.

[0057] The device body 40 defines an interior space of the device 11 that houses various elements designed to perform different functions of the device 11. This interior space may house, for example, a battery for powering the device 11, a controller for controlling the operation of the device 11, a planar heating chamber 50 (hereinafter "heating chamber 50") for heating the tobacco portion 15 of the tobacco article 12, etc. Of these elements, only the planar heating chamber 50 will be described in further detail with reference to FIG. 3.

[0058] 3 , the heating chamber 50 is configured to receive the tobacco article 12. The heating chamber 50 has a flat plate shape adapted to receive at least the tobacco portion 15 of the tobacco article 12. Like the tobacco article 12, the heating chamber 50 may also form a rectangular parallelepiped shape extending along the device axis X′, including a pair of parallel narrow walls (not visible) extending along the device axis X, a pair of parallel wide walls 54A, 54B also extending along the device axis X′, and a bottom wall 58 adjacent each of the walls and extending perpendicular to the device axis X. The bottom wall 58 therefore forms a closed end of the chamber 50. Opposite the bottom wall 58, the heating chamber 50 defines an opening configured to receive the tobacco article 12, such that the corresponding wide walls 14A, 14B of the tobacco article 12 face the corresponding wide walls 54A, 54B of the heating chamber 50, the corresponding narrow walls 13A, 13B of the tobacco article 12 face the corresponding narrow walls of the heating chamber 50, and the abutting end 18 of the tobacco article 12 faces the bottom wall 58. In the example of Figure 3, the abutting end 18 of the tobacco article 12 faces the bottom wall 58 without contacting the bottom wall 58. Alternatively, the abutting end 18 of the tobacco article 12 abuts the bottom wall 58. The opposing wide walls 14A, 14B, 54A, 54B and the opposing narrow walls 53A, 53B can contact each other or be spaced apart from each other.

[0059] In the example shown in Figure 3, the heating chamber 50 includes a first heating plate 70A that at least partially forms a wall of the heating chamber 50, more particularly a wide wall 54A of the heating chamber 50. The first heating plate 70A includes a continuous, advantageously smooth, heating surface 72A that is configured to contact the outer surfaces 30, 32 of the tobacco portion 15. For example, as shown in Figure 3, the heating surface 72A of the first heating plate 70A is configured to contact the first outer surface 30 of the tobacco portion 15.

[0060] In a variation (not shown), instead of a heating plate, the heating chamber 50 includes a long strip of flexible heater that includes two separate track patterns wrapped around the heating chamber such that the two patterns form the first heating surface 72A and the second heating surface 72B.

[0061] "Continuous" as used in reference to a heating surface means that the surface has no discontinuities other than its outer boundaries. In other words, a continuous heating surface extends continuously between its outer boundaries. Additionally, if a continuous heating surface is smooth, the continuous heating surface has at least a first derivative at every point except the outer boundaries.

[0062] Advantageously, as can be seen in Figure 3, the heating chamber 50 also includes a second heating plate 70B positioned opposite the first heating plate 70A. The first heating plate 70A and the second heating plate 70B thus at least partially form opposite walls of the heating chamber 50, with the second heating plate 70B forming the wide wall 54B of the heating chamber 50. The tobacco portion 15 is sandwiched between the two heating plates 70A, 70B. The second heating plate 70B includes a heating surface 72B configured to contact the second outer surface 32 of the tobacco portion 15. Advantageously, the heating surface 72B is also continuous and advantageously smooth.

[0063] According to the present invention, at least the heating surface 72A of the first heating plate 70A is designed to extend along only a partial area of ​​the tobacco portion 15. In other words, the area of ​​said heating surface 72A is comprised between 35% and 99% of the area of ​​the first outer surface 30 of the tobacco portion 15. In a preferred embodiment, the heating surface 72B of the second heating plate 70B is also designed to extend along only a partial area of ​​the tobacco portion 15. In other words, the area of ​​said heating surface 72B is comprised between 35% and 99% of the area of ​​the second outer surface 32 of the tobacco portion 15.

[0064] Advantageously, the area of ​​the heating surfaces 72A, 72B of the first heating plate 70A and / or the second heating plate 70B is comprised between 40% and 95%, preferably between 40% and 90%, more preferably between 45% and 85%, advantageously between 50% and 80%, advantageously between 50% and 75% of the area of ​​the corresponding outer surface 30, 32 of the tobacco portion 15.

[0065] In other words, the tobacco portion 15 protrudes from at least one end of the first heating plate 70A and / or the second heating plate 70B. Advantageously, as shown in Figure 4, the length and width of the first heating plate 70A and / or the second heating plate 70B are smaller than the length L15 and width W15 of the tobacco portion 15, so that the tobacco portion 15 protrudes from both ends of the first heating plate 70A and / or the second heating plate 70B.

[0066] Advantageously, the area of ​​the heating surfaces 72A, 72A of the first heating plate 70A and / or the second heating plate 70B is comprised between 15% and 60%, preferably between 20% and 50%, advantageously between 25% and 40% of the area of ​​the outer surface of the flat tobacco article 12.

[0067] In the example shown in Figures 3 and 4, each heating plate 70A, 70B forms a flat rectangular parallelepiped extending along the device longitudinal axis X' and having outer dimensions L70 x W70 x D70.

[0068] In the example of Figure 3, the heating plates 70A, 70B have substantially the same dimensions. Alternatively, the heating plates 70A, 70B have different dimensions.

[0069] Advantageously, the heating surface 72A, 72B of the or each heating plate 70A, 70B defines a length L70, measured along the device longitudinal axis X', that is comprised between 60% and 99%, preferably between 70% and 95%, more preferably between 75% and 90% of the length L15 of the corresponding outer surface 30, 32 of the tobacco portion 15, measured along the article longitudinal axis X.

[0070] Advantageously, the heating plate 70A, 70B, or the heating surface 72A, 72B of each heating plate 70A, 70B, defines a width W70, measured along a device transverse axis Y' perpendicular to the device longitudinal axis X', that is comprised between 60% and 99%, preferably between 70% and 95%, more preferably between 75% and 90% of the width W15 of the corresponding outer surface 30, 32 of the tobacco portion 15, measured along an article transverse axis Y perpendicular to the article longitudinal axis X.

[0071] The depth D70 of the or each heating plate 70A, 70B may depend on the dimensions of the tobacco article 15. For example, the depth D70 of the or each heating plate 70A, 70B is equal to or greater than 0.25 mm and equal to or less than 0.75 mm.

[0072] In the embodiment of FIG. 3, the first heating plate 70A and the second heating plate 70B are of the same dimensions and are aligned and positioned opposite each other along a vertical axis Z that is perpendicular to each of the plates 70A, 70B.

[0073] According to another embodiment (not shown), the first heating plate 70A and the second heating plate 70B are arranged opposite each other according to a vertical axis Z, said plates 70A, 70B being offset from each other according to an offset axis perpendicular to the vertical axis Z. In other words, the first heating plate 70A and the second heating plate 70B are arranged to form in a mid-plane located between the heating plates 70A, 70B at least one first zone corresponding to the overlapping zones of the orthogonal projections of the heating plates in the mid-plane and at least one second zone corresponding to the non-overlapping zones of the orthogonal projections.

[0074] The or each heating plate 70A, 70B may present a homogeneous body 75 made from the same material, such as a metal (such as copper), a ceramic, etc. Preferably, at least one or each heating plate 70A, 70B is made from a ceramic substrate, for example made from Al2O3, zirconia, silicon nitride, or aluminum nitride. In a variant, the or each heating plate 70A, 70B is made from a resin substrate layer, for example polyimide.

[0075] Heating plates 70A, 70B may be made of the same material or different materials (as shown in FIG. 3) depending on the desired thermal properties.

[0076] The or each heating plate 70A, 70B includes a specific heating element, e.g., a resistive element. Such resistive elements form, for example, resistive heater tracks 80 embedded in the body of the heating plate 70A, 70B and connected to a controller, as known per se. In the further description, it will be understood that supplying power to the heating plate will supply power to the resistive element associated with the respective heating plate 70A, 70B.

[0077] A controller (not shown) is configured to control the operation of the or each heating surface 72A, 72B, particularly the supply of power to the or each heating surface 72A, 72B, and in particular to the or each heating plate 70A, 70B, so that the or each heating surface 72A, 72B achieves a desired target temperature.

[0078] The target temperature is, for example, comprised between 240°C and 320°C and is, for example, equal to 280°C.

[0079] The first heating surface 72A and the second heating surface 72B may be operated at different target temperatures. Specifically, the controller may be configured to power the first heating plate 70A according to a first target temperature and power the second heating plate 70B according to a second target temperature. Each target temperature may be selected based on the characteristics of the heating plates, in particular the thermal capacity of the heating plates and / or the position of each heating plate 70A, 70B. Thus, heating of the tobacco portion may be optimized for the different thermal capacities and / or positions of the heating plates 70A, 70B.

[0080] It will be apparent to those skilled in the art that other embodiments can be implemented in various ways by combining different features of the above-described embodiments.

Claims

1. An aerosol generating device (11) configured to operate with a flat tobacco article (12) and including a flat heating chamber (50) extending along a device longitudinal axis (X'), The flat tobacco article (12) extends along an article longitudinal axis (X) and includes a tobacco portion (15) and a non-tobacco portion (16) arranged successively along the article longitudinal axis (X); the tobacco portion (15) defines a first outer surface (30) and a second outer surface (32) opposite the first outer surface (30); the heating chamber (50) is configured to receive at least the tobacco portion (15) of the flat tobacco article (12) and includes a continuous first heating surface (72A) configured to contact the first outer surface (30) of the tobacco portion (15); the area of ​​said heating surface (72A) is comprised between 35% and 99% of the area of ​​said first outer surface (30) of said tobacco portion (15); An aerosol generating device (11).

2. said area of ​​said first heating surface (72A) is comprised between 40% and 95%, preferably between 40% and 90%, more preferably between 45% and 85%, advantageously between 50% and 80%, advantageously between 50% and 75% of said area of ​​said first outer surface (30) of said tobacco portion (15); 2. An aerosol generating device (11) according to claim 1.

3. The heating chamber (50) further includes a second heating surface (72B) configured to contact the second outer surface (32) of the tobacco portion (15); 3. An aerosol generating device (11) according to claim 1 or 2.

4. said area of ​​said second heating surface (72B) is comprised between 35% and 99%, preferably between 40% and 95%, preferably between 40% and 90%, more preferably between 45% and 85%, advantageously between 50% and 80%, advantageously between 50% and 75% of said area of ​​said second outer surface (32) of said tobacco portion (15); 4. An aerosol generating device (11) according to claim 3.

5. the first heating surface (72A) and the second heating surface (72B) are of the same dimensions and are aligned and positioned opposite each other along a vertical axis (Z) perpendicular to each of the surfaces (72A, 72B); 5. An aerosol generating device (11) according to claim 3 or 4.

6. the first heating surface (72A) and the second heating surface (72B) are arranged opposite to each other along a vertical axis (Z) perpendicular to each of the heating surfaces (72A, 72B); The heating surfaces (72A, 72B) are offset from each other according to an offset axis perpendicular to the vertical axis (Z).

5. An aerosol generating device (11) according to claim 3 or 4.

7. the first heating surface (72A) and the second heating surface (72B) are operated at different target temperatures; An aerosol generating device (11) according to any one of claims 3 to 6.

8. the or each heating surface (72A, 72B) defines a length (L70), measured along the device longitudinal axis (X'), which length (L70) is comprised between 60% and 99%, preferably between 70% and 95%, more preferably between 75% and 90% of the length of the corresponding outer surface (30, 32) of the tobacco portion (15), measured along the article longitudinal axis (X); An aerosol generating device (11) according to any one of claims 1 to 7.

9. the or each heating surface (72A, 72B) defines a width (W70), measured along a device transverse axis (Y') perpendicular to the device longitudinal axis (X'), said width (W70) being comprised between 60% and 99%, preferably between 70% and 95%, more preferably between 75% and 90% of the width of the corresponding outer surface (30, 32) of the tobacco portion (15), measured along an article transverse axis (Y) perpendicular to the article longitudinal axis (X); An aerosol generating device (11) according to any one of claims 1 to 8.

10. The heating chamber (50) includes a first plate (70A) partially forming a wall of the heating chamber (50); the first heating plate (70A) includes the first heating surface (72A); The heating chamber (50) preferably includes a second heating plate (70B) that includes the second heating surface (72B); the first heating plate (70A) and the second heating plate (70B) partially form opposite walls of the heating chamber (50); An aerosol generating device (11) according to any one of claims 1 to 9.

11. the or each heating plate (70A, 70B) comprises a planar substrate and a resistive heating track (80) embedded in or mounted on said planar substrate; 11. An aerosol generating device (11) according to claim 10.

12. the planar substrate of the or each heating plate (70A, 70B) comprises a hard material, preferably selected between ceramic and metal; 12. An aerosol generating device (11) according to claim 11.

13. the planar substrate of the or each heating plate (70A, 70B) comprises a flexible, heat-resistant resin, preferably selected between polyimide and fluororesin; 12. An aerosol generating device (11) according to claim 11.

14. the heating chamber (50) comprises a long strip of flexible heater including two separate resistive track patterns wrapped around the heating chamber (50) such that the two separate resistive track patterns form the first heating surface (72A) and the second heating surface (72B), respectively; An aerosol generating device (11) according to any one of claims 1 to 9.

15. the or each heating surface (72A, 72B) is associated with a unique heating element; An aerosol generating device (11) according to any one of claims 1 to 14.

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