Aerosol generating device having a heating coating

Abstract

The present invention relates to an aerosol generating device for generating inhalable aerosols. The device comprises a heating chamber (10) configured to receive an aerosol-generating article (12) containing an aerosol-generating substrate. The heating chamber (10) comprises a heating element. The heating element is an electrically resistive coating (16). [Selected Figure] Figure 1

Description

Technical Field

[0001] The present invention relates to an aerosol generating device for generating an inhalable aerosol. Aerosol generating devices that heat an aerosol generating substrate such as tobacco without combustion are well known. These devices heat the aerosol generating substrate to a temperature high enough to create an aerosol for inhalation by the user.

Background Art

[0002] These aerosol generating devices typically comprise a heating chamber, and a relatively complex heating element is disposed within or surrounds the heating chamber. An aerosol generating article comprising an aerosol generating substrate can be inserted into the heating chamber and heated by the heating element. The heating element is typically configured as a heating blade and penetrates into the aerosol generating substrate of the aerosol generating article when the aerosol generating article is inserted into the heating chamber. Conventional heating elements mainly heat the center of the aerosol generating substrate.

Summary of the Invention

Problems to be Solved by the Invention

[0003] As a result, there is a need to provide a heating element that enables inexpensive and uniform heating.

Means for Solving the Problems

[0004] To solve this and for further purposes, the present invention proposes an aerosol generating device for generating an inhalable aerosol. The device comprises a heating chamber configured to receive an aerosol generating article containing an aerosol generating substrate. The heating chamber comprises a heating element. The heating element is an electrically resistive coating.

[0005] Constituting a heating element as an electrically resistive coating has several advantages. Since the coating can heat a relatively large area of the inserted aerosol-generating article, a more uniform heat distribution can be achieved. The more uniform heat distribution also has the effect that even if the heater is operated at a slightly lower temperature, the energy efficiency of heating may be higher.

[0006] When the heating element is configured as an electrically resistive coating, the possible shapes of the heating element may be diverse. Therefore, the shape of the heating element is not limited to conventional heater shapes such as a shape bent in a single direction, such as a cylinder or a cone. Using an electrically resistive coating allows for irregular shapes (e.g., a domed surface, a parabolic surface, or an irregular surface).

[0007] Conventional coil-shaped heaters may induce an electromagnetic field that can cause electromagnetic interference. Electromagnetic interference requires an additional layer of a metallic material to shield and block the electromagnetic field. In the present invention, due to the fact that the electrically resistive coating does not generate an electromagnetic field that causes electromagnetic interference, such additional components are not necessary.

[0008] The electrically resistive coating (or film) may be formed by atmospheric pressure chemical vapor deposition (APCVD), vacuum evaporation, sputtering, conventional CVD, plasma CVD, or flame pyrolysis. As another method, the material may be applied using other conventional coating methods such as wet spraying, powder coating, or dip coating. In some embodiments, the coating may be applied by powder sintering. Depending on the selected material composition and the method of applying the coating, the coating may require a drying, curing, or fixing step.

[0009] The electrically resistive coating may be applied to the side wall of the heating chamber, particularly to the inner wall of the side wall facing the inside of the heating chamber.

[0010] The coating provided on the side wall of the heating chamber may enable direct heating of the aerosol generating substrate contained in the aerosol generating article inserted into the heating chamber. The side wall of the heating chamber preferably comprises not only the base of the heating chamber but also the wall surrounding the longitudinal axis of the heating chamber. The heating chamber comprises an opening for inserting the aerosol generating article, which does not form part of the side wall. The heating chamber may have a hollow tubular shape for inserting an aerosol generating article having a cylindrical shape similar to a conventional cigarette. The opening of the heating chamber for inserting the article may be circular.

[0011] In addition to a further heating element such as a heating blade disposed centrally in the heating chamber, an electrically resistive coating may be provided. Next, the aerosol generating substrate may be heated uniformly not only from the inside but also from the outside.

[0012] The electrically resistive coating may include electrically resistive particles and a binder.

[0013] The resistive particles provide resistive heating characteristics to the coating. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, conductive ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, metal alloys, composite materials made of ceramic materials or metal materials. Such composite materials may include doped ceramics or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel-based, iron-based, cobalt-based, stainless steel-based superalloys, Timetal, and iron-manganese-aluminum-based alloys. In the composite material, the electrically resistive material may optionally be embedded in, encapsulated in, or coated with the insulating material, or vice versa, depending on the required energy transfer kinetics and external physicochemical properties.

[0014] In another embodiment, the electrically resistive coating material consists of a thin film of a molecularly bonded material such as, but not limited to, doped tin oxide made from tin oxide, or independent precursors such as tin chloride, methyl alcohol, H2O, and dopants DFE (such as difluoroethane (DFE) and antimony pentachloride).

[0015] The binder binds the resistive material particles, and the binder can be a polymer, a ceramic material, or an enamel frit. Suitable polymers include, but are not limited to, fluoropolymers, acrylics, and acrylates.

[0016] The binder may be configured to adhere to the side wall of the heating chamber. The binder may be configured as a material resistant to mechanical damage so that the electrically resistive coating is not damaged during insertion and removal of the aerosol-generating article and during operation of the aerosol-generating device.

[0017] The substrate may be disposed between the electrically resistive coating and the heating chamber.

[0018] The substrate to which the coating material is applied may be configured to withstand the operating temperature of the electrically resistive coating and is preferably not conductive. Suitable materials include, but are not limited to, ceramic materials, beryllium oxide (BeO), glass-ceramics, glass-based materials, aluminum nitride, quartz, and enameled metals. The substrate may optimize the bond between the electrically resistive coating and the side wall of the heating chamber.

[0019] The substrate may be configured to be thermally insulating. Using a thermal insulating material for the substrate inhibits heat transfer through the side wall of the heating chamber and directs the generated heat towards the inside of the heating chamber and thus towards the inserted aerosol-generating article. This increases the energy efficiency and performance of the device.

[0020] The device may further comprise a controller, a power source, and a contact, the contact being in electrical contact with the electrically resistive coating, and the controller being configured to control the supply of power from the power source to the electrically resistive coating via the contact.

[0021] The power source is preferably configured as a battery. The contacts are preferably arranged at a distance from each other at both ends of the electrically resistive coating such that the power supplied to the electrically resistive coating passes uniformly through the coating, thereby creating a uniform heat distribution across the surface of the coating. One contact may be arranged at the base of the side wall of the heating chamber, while the second contact may be in the form of a ring arranged circumferentially in the radial direction of the side wall of the heating chamber. In other words, one contact may be arranged at the base of the heating chamber, while the other contact may be arranged near the opening of the heating chamber.

[0022] The electrically resistive coating may be applied to the entire side wall of the heating chamber. Applying the coating to the entire side wall of the heating chamber may facilitate uniform heating of the aerosol-generating article inserted into the heating chamber.

[0023] The electrically resistive coating may be applied to a section of the side wall of the heating chamber adjacent to the opening of the heating chamber.

[0024] In this embodiment, the electrical resistance coating is not provided at the base of the heating chamber. Therefore, the aerosol-generating article is mainly heated adjacent to the opening of the heating chamber. This has the beneficial effect of having less residue leaking from the aerosol-generating article near the base of the heating chamber. Therefore, the contamination of the heating chamber after removing the aerosol-generating article can be reduced. In this regard, a typical aerosol-generating article includes an outer wrapper disposed around the outer periphery of the aerosol-generating article, while the portion of the aerosol-generating article facing the base of the heating chamber during and after insertion of the aerosol-generating article into the heating chamber is not covered by the wrapper. Therefore, the residue of the aerosol-generating substrate mainly exits the aerosol-generating article through this portion of the article. By not providing the electrical resistance coating at the base of the heating chamber, the heating of the substrate in this area is reduced, thereby reducing the substrate exiting the article adjacent to the base of the heating chamber in solid or gaseous form. Therefore, the contamination of the heating chamber can potentially be efficiently reduced.

[0025] The electrical resistance coating may be applied to a plurality of separate sections of the heating chamber, and each section of the electrical resistance coating may be configured to be separately controllable and operable.

[0026] Providing a plurality of sections of the electrical resistance coating has the effect of creating a plurality of heating elements. These plurality of heating elements can be separately controlled to heat separate portions of the aerosol generating substrate in the aerosol generating article inserted into the heating chamber. During operation of the device, for example when the user is smoking the device, it is preferred that a first portion of the aerosol generating substrate is heated for aerosol generation by operating a first section of the electrical resistance coating. After the user has smoked or after depletion of the aerosol generating substrate after a predetermined time, a second section of the electrical resistance coating may be activated and the first section may be deactivated. In this way, a plurality of portions of the aerosol generating substrate may be subsequently heated for aerosol generation by a plurality of subsequently operating sections of the electrical resistance coating. Separate contacts are provided as a result for different sections of the electrical resistance coating. Also, the controller may comprise a plurality of controller sections for controlling the plurality of sections of the electrical resistance coating.

[0027] The thickness of the electrical resistance coating may be configured to vary at different positions.

[0028] By varying the thickness of the electrical resistance coating at different positions, different electrical resistances are achieved at different positions of the electrical resistance coating. Thus, different heating temperatures are achieved using the same voltage at these different sections or positions of the electrical resistance coating. This may be utilized to volatilize different portions of the aerosol generating substrate in different ways. The plurality of independently controllable sections of the electrical resistance coating as described above may be combined with different thicknesses of these different sections.

[0029] The electrical resistance coating may be applied to the outside of the side wall of the heating chamber, and the side wall may be configured to be thermally conductive.

[0030] This embodiment is particularly advantageous when the electrically resistive coating is fragile, difficult to clean, or prone to organic contamination. As a result, the electrically resistive coating may be applied on the outer surface of the side wall of the heating chamber between the housing of the aerosol generating device and the side wall of the heating chamber. Therefore, not only the housing of the aerosol generating device but also the side wall of the heating chamber prevents the electrically resistive coating from coming into contact with an aerosol generating article, an aerosol generating substrate, or other external elements that may damage the electrically resistive coating. In all embodiments described in the context of the present invention, the electrically resistive coating may be applied directly to the side wall of the heating chamber facing the inside of the heating chamber or to the outside of the side wall of the heating chamber as described in the previous embodiment. Preferably, the coating is applied to the inside of the side wall facing the inside of the heating chamber and not to the outside of the heating chamber.

[0031] The base of the heating chamber may have a hemispherical shape. In this embodiment, the thermal energy generated at the base of the heating chamber within the hemisphere is directed towards the center point of the protruding sphere. Thus, the aerosol generating substrate of the aerosol generating article positioned at this point is rapidly heated to very quickly create an aerosol. In this embodiment, the aerosol generating coating provided at the base of the heating chamber shaped as a hemisphere may be provided as a section of the electrically resistive coating that can be controlled separately. This section may be operated first to very quickly create an aerosol, while a further section of the electrically resistive coating may be operated for a longer period to create an aerosol over a longer time.

[0032] The present invention further relates to a method of manufacturing an aerosol generating device for generating an inhalable aerosol, the method comprising i) providing a heating chamber configured to receive an aerosol generating article containing an aerosol generating substrate; and ii) coating the heating chamber with an electrically resistive coating acting as a heating element.

[0033] The invention will be described in more detail below with reference to the accompanying drawings.

Brief Description of the Drawings

[0034]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0035] Figure 1 shows an aerosol generator according to the present invention. The device includes a heating chamber 10. An aerosol generating article 12 may be inserted into the heating chamber 10. The heating chamber 10 includes a side wall 14. An electrically resistive coating 16 is provided on the side wall 14 of the heating chamber 10 to facilitate a heating element.

[0036] The electrically resistive coating 16 may be provided in addition to a further heating element such as a heating pin or heating blade aligned along the longitudinal axis of the heating chamber 10 and disposed centrally, or a heating coil disposed around the heating chamber 10. However, it is preferable that the electrically resistive coating 16 is the only heating element of the aerosol generator for heating the aerosol generating substrate contained in the aerosol generating article 12.

[0037] In Figure 1, the electrically resistive coating 16 is applied to the inner surface of the side wall 14 of the heating chamber 10. Therefore, the electrically resistive coating 16 radiates heat directly towards the aerosol generating article 12 inserted into the heating chamber 10.

[0038] Figure 1 further shows contacts 18, 20 that are electrically connected to the electrically resistive coating 16 such that current is supplied towards and can pass through the electrically resistive coating 16. As can be seen in Figure 1, the first contact 18 is disposed at the base of the heating chamber 10, while the second contact 20 is disposed near the opening of the heating chamber 10. In this way, the current passing through the electrically resistive coating 16 and provided to the electrically resistive coating 16 by the contacts 18, 20 passes uniformly through the electrically resistive coating 16. The second electrode 20 is preferably provided as a ring-shaped electrode adjacent to the opening of the heating chamber 10.

[0039] A controller 22 is provided that contacts a power source 24 to supply electrical energy towards and through the electrically resistive coating 16. The power source 24 is configured as a battery.

[0040] Figure 2 shows two embodiments of the electrically resistive coating 16. In Figure 2A, the electrically resistive coating 16 is applied directly on the inner surface of the side wall 14 of the heating chamber 10. The electrically resistive coating 16 includes not only electrically resistive particles 26 but also a binder 28. The electrically resistive particles 26 are embedded in the binder 28. Therefore, the binder 28 functions as a carrier.

[0041] In FIG. 2B, the electrically resistive coating 16 is applied to the outside of the side wall 14 of the heating chamber 10. The electrically resistive coating 16 in this embodiment and all other embodiments may be configured as an electrically resistive coating 16 consisting of electrically resistive particles 26 and a binder 28, as depicted in FIG. 2A. In all embodiments, a single layer of material as shown in FIG. 2B may also be utilized for the electrically resistive coating 16. Providing the electrically resistive coating 16 on the outside of the side wall 14 of the heating chamber 10 as depicted in FIG. 2B has the advantage that the electrically resistive coating 16 is protected from contamination or damage by the side wall 14 of the heating chamber 10. In the embodiment shown in FIG. 2B, the side wall 14 of the heating chamber 10 is preferably made of a thermally conductive material such that heat released by the electrically resistive coating 16 is transmitted into the heating chamber 10 and into the aerosol generating substrate disposed within the heating chamber 10 by the insertion of the aerosol generating article 12.

[0042] FIG. 3 shows a plurality of embodiments of the arrangement of the electrically resistive coating 16. In FIG. 3A, the electrically resistive coating 16 is not provided over the entire side wall 14 of the heating chamber 10 as depicted in FIGS. 1 and 2. In the embodiment shown in FIG. 3A, the electrically resistive coating 16 is provided only over a section of the heating chamber 10 adjacent to the opening of the heating chamber 10. In this embodiment, the aerosol generating article 12 inserted into the heating chamber 10 is not uniformly heated by the electrically resistive coating 16 but is selectively heated depending on the positioning of the electrically resistive coating 16. As shown in FIG. 3A, the electrically resistive coating 16 preferably heats the portion of the aerosol generating article 12 positioned adjacent to the opening of the heating chamber 10. In this way, the heating of the aerosol generating substrate near the electrically resistive coating 16 is primarily heated. This can reduce the contamination of the heating chamber 10 by residues of the aerosol generating substrate leaking from the portion of the aerosol generating article 12 facing the base of the heating chamber 10.

[0043] In the embodiment shown in FIG. 3B, a plurality of sections of the electrically resistive coating 16 are provided, which are individually and separately controllable and operable. These different sections of the electrically resistive coating 16 can be utilized to heat different sections of the aerosol generating substrate.

[0044] In FIG. 3C, an embodiment is shown in which different sections of the electrically resistive coating 16 are provided, each of these sections having a different thickness. These different thicknesses result in different electrical resistances for the respective sections and thus different heating temperatures. The sections depicted in FIG. 3C may be separately controllable and operable or may be configured as a single coating layer.

[0045] FIG. 4 shows an embodiment of the heating chamber 10 in which the base of the heating chamber 10 is formed as a hemisphere. As a result, the electrically resistive coating 16 applied to the hemispherical area has a hemispherical shape. The heat released from the coating in this area is thus focused on the central point of the aerosol generating article 12, thereby resulting in rapid heating and aerosol generation at this part of the aerosol generating substrate of the aerosol generating article 12.

Claims

**Claim 1** An aerosol generating device for generating an inhalable aerosol, comprising a heating chamber configured to receive an aerosol generating article containing an aerosol generating substrate, the heating chamber comprising a heating element, and the heating element being an electrically resistive coating, wherein the thickness of the electrically resistive coating is configured to vary at different positions so that different heating temperatures are provided at different positions within the heating chamber, wherein the electrically resistive coating comprises electrically resistive particles and a binder, wherein a substrate is disposed between the electrically resistive coating and the side wall of the heating chamber, wherein the substrate is heat-insulating, an aerosol generating device. **Claim 2** The aerosol generating device according to claim 1, wherein the device further comprises a controller, a power source, and a contact, the contact being in electrical contact with the electrically resistive coating, and the controller being configured to control the supply of power from the power source to the electrically resistive coating via the contact. **Claim 3** The aerosol generating device according to claim 1 or 2, wherein the electrically resistive coating is applied to a plurality of separate sections of the heating chamber, and each section of the electrically resistive coating is configured to be separately controllable and operable. **Claim 4** The aerosol generating device according to any one of claims 1 to 3, wherein the base of the heating chamber has a hemispherical shape. **Claim 5** A method of manufacturing an aerosol generating device for generating an inhalable aerosol, comprising: i) providing a heating chamber configured to receive an aerosol generating article containing an aerosol generating substrate; ii) coating the heating chamber with an electrically resistive coating acting as a heating element, wherein the thickness of the electrically resistive coating is configured to vary at different positions so that different heating temperatures are provided at different positions within the heating chamber, and the electrically resistive coating comprises electrically resistive particles and a binder; including, wherein a substrate is disposed between the electrically resistive coating and the side wall of the heating chamber, wherein the substrate is heat-insulating, a method.

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