Cartridge having a reflective surface for use in an aerosol-generating system

Abstract

A cartridge (10) for an aerosol-generating device, the cartridge comprising: a housing (12) defining a chamber (18) containing an aerosol-generating substrate (16); a heating element (14) for heating the aerosol-generating substrate, at least a portion of the heating element extending into the chamber; wherein the housing comprises a reflective surface (25) facing an interior of the chamber; wherein the aerosol-generating substrate comprises a solid aerosol-generating substrate.

Description

[0001] CARTRIDGE HAVING A REFLECTIVE SURFACE FOR USE IN AN AEROSOLGENERATING SYSTEM

[0002] The present disclosure relates to a cartridge for use with an aerosol-generating device. In particular, but not exclusively, the present disclosure relates to a cartridge having a reflective surface for use with an aerosol-generating device, and which is configured to generate an aerosol and deliver the aerosol into the mouth of a user. The present disclosure also relates to an aerosol-generating system comprising the cartridge and an aerosol-generating device.

[0003] Aerosol-generating articles in which an aerosol-generating substrate, such as a tobacco-containing substrate, is heated rather than combusted, are known in the art. Such articles typically generate an aerosol by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material, which is arranged in thermal contact with the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

[0004] Electrically heated aerosol-generating devices for use with the aerosol-generating articles described above are also known. Such devices typically include a power source for supplying electrical power to one or more electrical heating elements for heating the aerosolgenerating substrate of the aerosol-generating article. The one or more electrical heating elements can either be part of the aerosol-generating device or part of the aerosol-generating article. Where the heating element is part of the aerosol-generating article, the heating element typically has electrical contacts which are arranged to connect to corresponding electrical contacts arranged in the aerosol-generating device. Electrical power is supplied to the heating element via the electrical contacts.

[0005] A problem that can be encountered with conventional aerosol-generating articles is heat losses through the walls of the container holding the aerosol-generating substrate. This can result in heat transfer to the exterior surface of the container and an increased temperature profile on the exterior surface of the container, which can make the aerosol-generating article uncomfortable, or even unsafe, to handle. Furthermore, the loss of heat from the container means less heat is available to heat the aerosol-generating substrate, which can result in less aerosol, or an aerosol of reduced quality, being produced. This adversely affects the performance of the aerosol-generating article and can detract from the consumer experience.

[0006] It would be desirable to provide a cartridge for an aerosol-generating device that is more energy efficient and comfortable to handle. In particular, it would be desirable to provide a cartridge for an aerosol-generating device that reduces energy losses from the cartridge and reduces the temperature of the external surface of the cartridge following heating.

[0007] According to an example of the present disclosure, there is provided a cartridge for an aerosol-generating device. The cartridge may comprise a housing. The housing may define a chamber. The chamber may contain an aerosol-generating substrate. The cartridge may comprise a heating element for heating the aerosol-generating substrate. At least a portion of the heating element may extend into the chamber. The housing may comprise a reflective surface. The reflective surface may face an interior of the chamber.

[0008] According to an example of the present disclosure, there is provided a cartridge for an aerosol-generating device. The cartridge comprising: a housing defining a chamber containing an aerosol-generating substrate; and a heating element for heating the aerosolgenerating substrate. At least a portion of the heating element extends into the chamber. The housing comprises a reflective surface facing an interior of the chamber.

[0009] As used herein, the term “cartridge” relates to a component that interacts with an aerosol-generating device to generate an aerosol.

[0010] As used herein, the term “aerosol-generating device” relates to a device that interacts with a cartridge to generate an aerosol.

[0011] As used herein, the term “reflective surface” refers to a surface that reflects more radiation, in particular more thermal radiation, than it emits.

[0012] Advantageously, providing the cartridge with a housing having a reflective surface facing an interior of the chamber may help to reduce thermal energy losses from the cartridge compared to a cartridge housing that does not have a reflective surface. Furthermore, the reflective surface may help to reduce heat transfer to the outer surface of the cartridge by reflecting more heat inwardly, that is, back into the chamber. This reduces the temperature of the external surface of the cartridge during and following heating and reduces the likelihood of hotspots forming on the outer surface of the cartridge. This may make the cartridge more comfortable and safe to handle when the cartridge is separated from the device shortly after heating, for example, if the cartridge needs replacing. Furthermore, the reflective surface may help to reduce thermal energy losses from the cartridge and improves heat retention within the chamber containing the aerosol-generating substrate. This may help to improve the energy efficiency of the cartridge and the aerosol-generating device used to supply power to the cartridge. This may also help generate a more consistent and better quality aerosol, thereby improving the consumer experience.

[0013] The reflective surface may have an emissivity of less than 0.2, preferably less than 0.15, and more preferably less than 0.1.

[0014] As used herein, the term “emissivity” is defined as the ratio of the energy radiated from a material's surface to that radiated from a perfect emitter (known as a blackbody), at the same temperature and wavelength. It is a dimensionless number between 0 (for a perfect reflector) and 1 (for a perfect emitter).

[0015] The housing may comprise a reflector component arranged on an inner surface of the housing. The reflector component may comprise the reflective surface. A reflector component has been found to be one effective way of providing a reflective surface within a cartridge.

[0016] The reflector component may comprise a polished metallic or ceramic layer that forms the reflective surface.

[0017] The housing may comprise a reflective coating arranged on an inner surface of the housing. The reflective coating may form the reflective surface. A reflective coating has been found to be another effective way of providing a reflective surface within a cartridge. An advantage a reflective coating is that it is compatible with existing cartridge designs and can be applied without substantial modification to the overall structure of the cartridge or housing. This enables easy integration with existing production methods. Techniques such as physical vapor deposition (PVD) or chemical vapor deposition (CVD) make it possible to add the reflective coating without altering the cartridge’s dimensions or significantly impacting production costs.

[0018] The reflective coating can be made from any suitable material. For example, the reflective coating may comprise a metal, metal alloy or ceramic. The reflective coating may comprise a material selected from one or more of aluminium, silver, gold, zirconia, alumina, titanium nitride, chromium, and stainless steel.

[0019] The reflective coating may be polished. The reflective coating may have a surface roughness of less than 0.20 micrometres Ra, preferably less than 0.15 micrometres Ra, and more preferably less than 0.10 micrometres Ra.

[0020] As used herein, the term “surface roughness” refers to the measurement of the relative smoothness of a surface’s profile, which is calculated via the microscopic deviations (peaks and valleys) in a surface's true form. As used herein, the term “Ra” refers to the “average roughness” of a surface and is the arithmetic average between peaks and valleys on a surface. A lower Ra value is indicative of less variation between the peaks and troughs on a surface, that is, a smoother surface.

[0021] The reflective coating may have a thickness of between 5 nanometres and 200 nanometres, optionally between 5 nanometres and 150 nanometres, optionally between 5 nanometres and 100 nanometres and further optionally between 5 nanometres and 50 nanometres.

[0022] The housing may comprise a first housing end section. The housing may comprise a second housing end section. The housing may comprise a side wall. The side wall may circumscribe the chamber. The side wall may extend between the first and second housing end sections. The reflective surface may be arranged on an inner surface of the side wall.

[0023] The side wall may be made from any suitable material. The side wall may comprise a metal, metal alloy or ceramic. The side wall may comprise an iron-based alloy such as stainless steel or an iron aluminide. The side wall may comprise a nickel-based alloy such as nichrome. The side wall may comprise a ceramic such as alumina. The side wall may comprise a metal with a ceramic coating.

[0024] The side wall may comprise a material having a thermal conductivity of less than 20 W / m.K.

[0025] The reflective surface may cover a portion of the area of the inner surface of the side wall. The reflective surface may cover more than 50 percent of the inner surface of the side wall. The reflective surface may cover more than 60 percent of the inner surface of the side wall. The reflective surface may cover more than 70 percent of the inner surface of the side wall. The reflective surface may cover more than 80 percent of the inner surface of the side wall. The reflective surface may cover more than 90 percent of the inner surface of the side wall. The reflective surface may cover substantially the entirety of area of the inner surface of the side wall.

[0026] The first housing end section may comprise a proximal end plug. The proximal end plug may be inserted into an opening defined by the inner surface of the side wall at the proximal end of the cartridge. The second housing end section may comprise a distal end plug. The distal end plug may be inserted into an opening defined by the inner end surface of the side wall at the distal end of the cartridge.

[0027] As used herein, the terms “proximal” and “distal” are used to describe the positions of components, or portions of components, of cartridges, aerosol-generating devices and aerosol-generating systems relative to a consumer. Cartridges, aerosol-generating devices and aerosol-generating systems may comprise a proximal end, which, in normal use, is closer to the consumer than the distal end. Cartridges, aerosol-generating devices and aerosolgenerating systems may comprise a distal end opposite the proximal end.

[0028] An inner end of the proximal end plug may comprise a reflective surface. An inner end of the distal end plug may comprise a reflective surface.

[0029] The proximal end plug may define the proximal end of the cartridge.

[0030] The distal end plug may define the distal end of the cartridge.

[0031] The side wall may extend from the proximal end of the cartridge to the distal end of the cartridge. The proximal end plug, the distal end plug and the side wall may define the chamber.

[0032] The distal end plug may comprise one or more electrical contacts arranged at an external surface of the cartridge. The one or more electrical contacts may be connected to the heating element. The one or more electrical contacts may be configured to connect to corresponding electrical contacts arranged in an aerosol-generating device.

[0033] The cartridge may comprise one or more air inlets. Preferably, the one or more air inlets are in the distal end plug. The one or more air inlets may be a single air inlet. The one or more air inlets may be a plurality of air inlets.

[0034] The cartridge may comprise one or more aerosol outlets. Preferably, the one or more aerosol outlets are in the proximal end plug. The one or more aerosol outlets may be a single aerosol outlet. The one or more aerosol outlets may be a plurality of aerosol outlets.

[0035] The chamber may extend between the one or more air inlets and the one or more aerosol outlets.

[0036] The cartridge may have a length between a proximal end of the cartridge and a distal end of the cartridge. The length of the cartridge may be determined in a direction parallel to the longitudinal axis of the cartridge. The length of the cartridge may be greater than or equal to 10 millimetres, preferably greater than or equal to 12 millimetres, or most preferably greater than or equal to 14 millimetres.

[0037] The length of the cartridge may be less than or equal to 40 millimetres, preferably less than or equal to 30 millimetres, or most preferably less than or equal to 20 millimetres.

[0038] For example, the cartridge may have a length of between 10 millimetres and 40 millimetres, preferably between 10 millimetres and 30 millimetres, or most preferably between 14 millimetres and 20 millimetres.

[0039] The cartridge may have a width in a first direction perpendicular to the longitudinal axis of the cartridge. The width of the cartridge may be greater than or equal to 5 millimetres, preferably greater than or equal to 6 millimetres, or most preferably greater than or equal to 7 millimetres.

[0040] The width of the cartridge may be less than or equal to 20 millimetres, preferably less than or equal to 15 millimetres, or most preferably less than or equal to 12 millimetres.

[0041] For example, the cartridge may have a width of between 5 millimetres and 20 millimetres, preferably between 5 millimetres and 15 millimetres, or most preferably between 7 millimetres and 12 millimetres.

[0042] The cartridge may have a thickness in a second direction perpendicular to the longitudinal axis of the cartridge and to the first direction. The thickness of the cartridge may be greater than or equal to 2 millimetres, preferably greater than or equal to 3 millimetres, or most preferably greater than or equal to 4 millimetres.

[0043] The thickness of the cartridge may be less than or equal to 15 millimetres, preferably less than or equal to 10 millimetres, or most preferably less than or equal to 8 millimetres.

[0044] For example, the cartridge may have a thickness of between 2 millimetres and 15 millimetres, preferably between 3 millimetres and 10 millimetres, or most preferably between 4 millimetres and 8 millimetres.

[0045] The side wall of the housing may have a thickness of greater than or equal to 1 millimetre, preferably greater than or equal to 2 millimetres, or most preferably greater than or equal to 3 millimetres.

[0046] The side wall of the housing may have a thickness of less than or equal to 7 millimetres, preferably less than or equal to 5 millimetres, or most preferably less than or equal to 4 millimetres.

[0047] For example, the side wall of the housing may have a thickness of between 1 millimetre and 7 millimetres, preferably between 1 millimetre and 5 millimetres, or most preferably between 1 millimetre and 4 millimetres.

[0048] The proximal end plug may have a dimension along a longitudinal axis of the cartridge of greater than or equal to 2 millimetres, preferably greater than or equal to 3 millimetres, or most preferably greater than or equal to 4 millimetres.

[0049] The proximal end plug may have a dimension along a longitudinal axis of the cartridge of less than or equal to 15 millimetres, preferably less than or equal to 10 millimetres, or most preferably less than or equal to 8 millimetres.

[0050] For example, the proximal end plug may have a dimension along a longitudinal axis of the cartridge of between 2 millimetres and 15 millimetres, preferably between 3 millimetres and 10 millimetres, or most preferably between 4 millimetres and 8 millimetres.

[0051] The distal end plug may have a dimension along a longitudinal axis of the cartridge of greater than or equal to 2 millimetres, preferably greater than or equal to 3 millimetres, or most preferably greater than or equal to 4 millimetres.

[0052] The distal end plug may have a dimension along a longitudinal axis of the cartridge of less than or equal to 10 millimetres, preferably less than or equal to 8 millimetres, or most preferably less than or equal to 6 millimetres.

[0053] For example, the distal end plug may have a dimension along a longitudinal axis of the cartridge of between 2 millimetres and 10 millimetres, preferably between 3 millimetres and 8 millimetres, or most preferably between 4 millimetres and 6 millimetres.

[0054] The dimension of the proximal end plug along a longitudinal axis of the cartridge is preferably greater than the corresponding dimension of the distal end plug along a longitudinal axis of the cartridge.

[0055] The heating element may be mounted on the second housing end section at a distal end of the housing.

[0056] The heating element may be an internal heating element. The internal heating element may be embedded in or at least partially surrounded by the aerosol-generating substrate. The internal heating element may be a pin or a blade.

[0057] The heating element may be a planar heating element. The heating element may comprise one or more heating surfaces for heating the aerosol-generating substrate to form an aerosol. The one or more heating surfaces may be planar heating surfaces. The heating element may be substantially or entirely planar. The heating element may be oriented so that a plane of the heating element extends across the width of the cartridge.

[0058] The heating element may have a serpentine shape. The heating element may comprise a plurality of segments. The heating element may comprise a plurality of segments extending parallel to the longitudinal axis of the cartridge. The heating element may be a self- supporting track which extends through the chamber.

[0059] The heating element may an external heating element. The external heating element may at least partially surround the aerosol-generating substrate.

[0060] The heating element may be a resistive heating element. The heating element may comprise an electrically resistive material.

[0061] The heating element may be formed from an iron-based alloy. The heating element may be formed from a nickel alloy. The heating element may be formed from a ceramic. The heating element may be formed from stainless steel. The heating element may be formed from SS316L stainless steel iron aluminides. The heating element may be formed from nichrome. The heating element may be formed from a ceramic coated metal.

[0062] The heating element may have a length of greater than or equal to 13 millimetres, greater than or equal to 14 millimetres, greater than or equal to 15 millimetres, or greater than or equal to 16 millimetres.

[0063] The heating element may have a length of less than or equal to 20 millimetres, less than or equal to 19 millimetres, less than or equal to 18 millimetres, or less than or equal to 17 millimetres.

[0064] For example, the heating element may have a length of between 13 millimetres and 20 millimetres, between 14 millimetres and 19 millimetres, between 15 millimetres and 18 millimetres, or between 16 millimetres and 17 millimetres.

[0065] The heating element may comprise a susceptor element.

[0066] As used herein, the term “susceptor” denotes a material that is capable of being heated when penetrated by a varying magnetic field.

[0067] The susceptor element may be embedded in or at least partially surrounded by the aerosol-generating substrate.

[0068] The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to generate an aerosol from the aerosol-generating substrate. For example, the susceptor element may comprise a metal or carbon. The susceptor element may comprise or consist of a ferromagnetic material, for example a ferromagnetic alloy, ferritic iron, or a ferromagnetic steel or stainless steel. A suitable material may be, or comprise, aluminium. The susceptor element may be formed from 400 series stainless steels, for example grade 410, or grade 420, or grade 430 stainless steel.

[0069] Where a susceptor element is provided, the cartridge or an aerosol-generating device may comprise an inductor coil arranged to inductively heat the susceptor element. The inductor coil may at least partly circumscribe the susceptor element.

[0070] The heating element may comprise a dielectric heating element. In particular, the dielectric heating element may comprise a dielectric material. The dielectric heating element may be configured to use radio-frequency (RF) electric waves that cause a dipole interaction with the dielectric material to heat the aerosol-generating substrate.

[0071] The heating element may comprise an infrared heating element. The infrared heating element may be configured to heat the aerosol-generating substrate using infrared electromagnetic radiation.

[0072] The chamber of the cartridge of the present disclosure contains an aerosol-generating substrate. As used herein, the term “aerosol-generating substrate” relates to a substrate capable of releasing volatile compounds that can form an aerosol. Such volatile compounds can be released by heating the aerosol-generating substrate.

[0073] Preferably, the aerosol-generating substrate is a solid aerosol-generating substrate.

[0074] As used herein, the term “solid” refers to an aerosol-generating substrate that is not a liquid or a gas and which does not flow such that it retains its shape and form at room temperature. In the context of the present invention, the term “solid” encompasses gel materials and compositions.

[0075] The aerosol-generating substrate may be in the form of one or more sheets of a solid aerosol-generating substrate. Preferably, the one or more sheets of solid aerosol-generating substrate comprise at least one aerosol former and at least one of nicotine and tobacco.

[0076] As used herein, the term “sheet” describes a laminar element having a width and length substantially greater than the thickness thereof.

[0077] The one or more sheets of solid aerosol-generating substrate may be provided on a suitable carrier element. For example, the one or more sheets of solid aerosol-generating substrate may be deposited onto at least one surface a sheet of an inert carrier material, such as paper or cardboard. This may provide improved rigidity to the one or more sheets of solid aerosol-generating substrate, which may facilitate the process of filling the cartridge with the one or more sheets during production.

[0078] The one or more sheets of solid aerosol-generating substrate may be in the form of one or more gathered sheets. As used herein, the term “gathered” denotes that a sheet is convoluted, folded, or otherwise compressed or constricted substantially transversely to a defined axis.

[0079] Alternatively or in addition, the one or more sheets of solid aerosol-generating substrate may be in the form of one or more crimped sheets, preferably, one or more gathered crimped sheets. As used herein, the term “crimped” denotes a sheet having a plurality of substantially parallel ridges or corrugations.

[0080] The one or more sheets of solid aerosol-generating substrate may comprise one or more sheets of homogenised plant material, preferably homogenised tobacco material. The aerosol former content of the homogenised tobacco material is preferably within the ranges defined above for aerosol-generating substrate having a relatively low aerosol former content.

[0081] Alternatively or in addition, the one or more sheets of solid aerosol-generating substrate may comprise one or more sheets comprising an aerosol-generating film, comprising a cellulosic based film forming agent, nicotine and the aerosol former. The aerosolgenerating film may further comprise a cellulose based strengthening agent. The aerosolgenerating film may further comprise water, preferably 30 percent by weight of less of water.

[0082] As used herein, the term “film” is used to describe a solid laminar element having a thickness that is less than the width or length thereof. The film may be self-supporting.

[0083] The aerosol former content of the aerosol-generating film is within the ranges defined above for aerosol-generating substrates having a relatively high aerosol former content.

[0084] In the context of the present invention the term “cellulose based film-forming agent” is used to describe a cellulosic polymer capable, by itself or in the presence of an auxiliary thickening agent, of forming a continuous film. Preferably, the cellulose based film-forming agent is selected from the group consisting of hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), ethylcellulose (EC), hydroxyethyl methyl cellulose (HEMC), hydroxyethyl cellulose (HEC), hydroxypropyl cellulose (HPC), and combinations thereof. In particularly preferred embodiments, the cellulose based film-forming agent is HPMC.

[0085] Suitable aerosol-generating films for use as the aerosol-generating substrate are described in WC-A-2020 / 207733 and WO-A-2022 / 074157.

[0086] Alternatively or in addition, the one or more sheets of solid aerosol-generating substrate may comprise one or more sheets comprising a gel composition that includes nicotine, at least one gelling agent and the aerosol former. The gel composition is preferably tobacco free.

[0087] Suitable gel compositions for use as the aerosol-generating substrate are described in WO-A-2021 / 170642.

[0088] In other embodiments, the aerosol-generating substrate may be in the form of a shredded aerosol-generating substrate. Preferably, the shredded aerosol-generating substrate comprises at least one aerosol former and at least one of tobacco and nicotine.

[0089] As used herein, the term “shredded” describes an aerosol-generating substrate that is in the form of a plurality of shreds or strips. In general, the shredded aerosol-generating substrate is formed by the cutting or shredding of a larger portion of the aerosol-generating substrate, such as a sheet, leaf or other piece of plant material. The individual strips or strands are typically elongate in form, with a length that is greater than the width and thickness.

[0090] The shredded aerosol-generating substrate may be in the form of shredded tobacco material, such as cut filler. Alternatively, the shredded aerosol-generating substrate may be in the form of a shredded sheet of homogenised plant material, such as a homogenised tobacco material. Alternatively, the shredded aerosol-generating substrate may be in the form of a shredded non-tobacco material, as described in more detail below.

[0091] As used herein, the term “cut filler” is used to describe to a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

[0092] According to another example of the present disclosure, there is provided an aerosolgenerating system. The aerosol-generating system may comprise any of the cartridges described above. The aerosol-generating system may comprise an aerosol-generating device. The aerosol-generating device may comprise a power source. The aerosolgenerating device may comprise control circuitry for controlling the supply of power from the power source to the heater.

[0093] According to another example of the present disclosure, there is provided an aerosolgenerating system comprising any of the cartridges described above and an aerosolgenerating device. The aerosol-generating device comprises: a power source; and control circuitry for controlling the supply of power from the power source to the heater.

[0094] The power source may be configured to provide power to the heater element to heat the aerosol-generating substrate to generate an aerosol. The power source may be a DC power source. The power source may a battery. The power source may be rechargeable. The power source may have a capacity that allows for the storage of enough energy for one or more user operations, for example one or more aerosol-generating experiences.

[0095] The aerosol-generating device may further comprise a device cavity configured to receive at least a part of the cartridge. The device cavity may have a closed end and an open end. The cartridge may be insertable into the device cavity via the open end. The device cavity may have substantially the same cross-sectional shape as the cartridge.

[0096] The device cavity of the aerosol-generating device may be at least partially defined by a device housing.

[0097] The device housing may comprise one or more of a metal, a plastic, a composite and a metal alloy. Preferably, the device housing comprises one or more of polycarbonate (PC), acrylonitrile butadiene styrene (ABS), liquid crystalline polymer (LCP), copolyester, polyetheretherketone (PEEK), cyclic olefin copolymer (COC), aluminium, an aluminium alloy, magnesium and carbon fibre reinforced polymer.

[0098] Where a susceptor element is provided either as part of the cartridge, the aerosolgenerating device may comprise the inductor coil arranged to inductively heat the susceptor element. Where the aerosol-generating device comprises a device cavity, the inductor coil may at least partly circumscribe the device cavity. The inductor coil may be arranged to coaxially circumscribe the device cavity.

[0099] The control circuity may comprise a controller. The controller may be configured to control the supply of power from the power supply to the heater element. The controller may be electrically connected to the power supply. The controller may be configured to control the power output from the power supply to control whether the heater element is on or off. The controller may be configured to control the power output from the power supply to control the temperature of the heater element.

[0100] The aerosol-generating device may further comprise a mouthpiece. During use, a user may draw on the mouthpiece to receive aerosol generated in the cartridge.

[0101] The mouthpiece may be configured to move between an open position and a closed position. When the mouthpiece is in the open position, the cartridge may be inserted into or removed from the device cavity. When the mouthpiece is in the closed position, the cartridge may be secured within the aerosol-generating device.

[0102] The mouthpiece may comprise one or more of a metal, plastic and a plant based material. Preferably, the mouthpiece comprises one or more of polycarbonate (PC), acrylonitrile butadiene styrene (ABS), liquid crystalline polymer (LCP), copolyester, polyetheretherketone (PEEK), cyclic olefin copolymer (COC), aluminium, stainless steel, wood and bamboo.

[0103] The aerosol-generating device may comprise a device air inlet. The aerosol-generating device may comprise a device aerosol outlet.

[0104] The device air inlet may be disposed at a distal end of the aerosol-generating device.

[0105] The mouthpiece may comprise the device aerosol outlet. The device aerosol outlet may be disposed at a proximal end of the aerosol-generating device.

[0106] The cartridge and the aerosol-generating device may be configured such that the one or more electrical contacts of the cartridge electrically connect to corresponding electrical contacts of the aerosol-generating device.

[0107] The aerosol-generating system may be configured such that, during use, air passes into the device air inlet, through the device cavity into the one or more air inlets of the cartridge, through the aerosol-generating substrate in the substrate compartment. The aerosolgenerating system may be configured such that, during use, aerosol generated in the substrate compartment is entrained in the air flow and passes to the one or more air outlets of the cartridge, and subsequently to the device aerosol outlet.

[0108] According to another example of the present disclosure, there is provided a method of manufacturing a cartridge for an aerosol-generating system. The method may comprise providing a housing. The housing may define a chamber for containing an aerosol-generating substrate. The method may comprise providing the housing with a reflective surface. The reflective surface may face an interior of the chamber. The method may comprise providing a heating element for heating the aerosol-generating substrate. At least a portion of the heating element may extend into the chamber. The method may comprise providing an aerosol-generating substrate within the chamber.

[0109] According to another example of the present disclosure, there is provided a method of manufacturing a cartridge for an aerosol-generating system. The method comprises: providing a housing defining a chamber for containing an aerosol-generating substrate; providing the housing with a reflective surface facing an interior of the chamber; providing a heating element for heating the aerosol-generating substrate, wherein at least a portion of the heating element extends into the chamber; and providing an aerosol-generating substrate within the chamber.

[0110] The step of providing the housing with a reflective surface may comprise depositing a reflective coating on an inner wall of the housing. The deposition process used to deposit the reflective coating may be selected from one or more of the following: physical vapour deposition, chemical vapour deposition and sputtering. A reflective coating has been found to be another effective way of providing a reflective surface within a cartridge. An advantage a reflective coating is that it is can be applied without substantial modification to the overall structure of the cartridge or housing. This enables easy integration with existing production methods. Techniques such as physical vapor deposition (PVD) or chemical vapor deposition (CVD) enable precise control over the thickness of the coating and make it possible to add the reflective coating without altering the cartridge’s dimensions or significantly impacting production costs.

[0111] The method may further comprise polishing the reflective surface. Advantageously, this improves the surface finish of the reflective surface and therefore its reflectivity.

[0112] Features described in relation to one of the above examples may equally be applied to other examples of the present disclosure.

[0113] The invention is defined in the claims. However, below there is provided a non- exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

[0114] Example Ex1 : A cartridge for an aerosol-generating device, the cartridge comprising a housing defining a chamber for containing an aerosol-generating substrate.

[0115] Example Ex2: A cartridge according to Example Ex1 , further comprising a heating element for heating the aerosol-generating substrate.

[0116] Example Ex3: A cartridge according to Example Ex2, wherein at least a portion of the heating element extending into the chamber.

[0117] Example Ex4: A cartridge according to any of Examples Ex1 to Ex3, wherein the housing comprises a reflective surface facing an interior of the chamber.

[0118] Example Ex5: A cartridge according to Example Ex4, wherein the reflective surface has an emissivity of less than 0.2, preferably less than 0.15, and more preferably less than 0.1.

[0119] Example Ex6: A cartridge according to Example Ex4 or Ex5, wherein the housing comprises a reflector component arranged on an inner surface of the housing, the reflector component comprising the reflective surface.

[0120] Example Ex7: A cartridge according to Example Ex6, wherein the reflector component comprises a polished metallic or ceramic layer that forms the reflective surface.

[0121] Example Ex8: A cartridge according to Example Ex4 or Ex5, wherein the housing comprising a reflective coating arranged on an inner surface of the housing, the reflective coating forming the reflective surface.

[0122] Example Ex9: A cartridge according to Example Ex8, wherein the reflective coating comprises a metal, metal alloy or ceramic.

[0123] Example Ex10: A cartridge according to Example Ex8 or Ex9, wherein the reflective coating comprises a material selected from one or more of aluminium, silver, gold, zirconia, alumina, titanium nitride, chromium, and stainless steel.

[0124] Example Ex11 : A cartridge according to any of Examples Ex8 to Ex10, wherein the reflective coating is polished and has a surface roughness of less than 0.20 micrometres Ra, preferably less than 0.15 micrometres Ra, and more preferably less than 0.10 micrometres Ra.

[0125] Example Ex12: A cartridge according to any of Examples Ex8 to Ex11 , wherein the reflective coating has a thickness of between 5 nanometres and 200 nanometres, optionally between 5 nanometres and 150 nanometres, optionally between 5 nanometres and 100 nanometres and further optionally between 5 nanometres and 50 nanometres.

[0126] Example Ex13: A cartridge according to any preceding example, wherein the housing comprises: a first housing end section; a second housing end section; and a side wall circumscribing the chamber and extending between the first and second housing end sections; wherein the reflective surface is arranged on an inner surface of the side wall.

[0127] Example Ex14: A cartridge according to Example Ex13, wherein the heating element is mounted on the second housing end section at a distal end of the housing.

[0128] Example Ex15: A cartridge according to any one of examples Ex13 or Ex14, wherein the second housing end section comprises one or more electrical contacts arranged at an external surface of the cartridge.

[0129] Example Ex16: A cartridge according to any preceding example, wherein the cartridge comprises one or more air inlets.

[0130] Example Ex17: A cartridge according to any preceding example, wherein the cartridge comprises one or more aerosol outlets.

[0131] Example Ex18: A cartridge according to any preceding example, wherein the aerosolgenerating substrate is a solid aerosol-generating substrate.

[0132] Example Ex19: A cartridge according to any preceding example, wherein the heater element is a resistive heater element.

[0133] Example Ex20: A cartridge according to any preceding example, wherein the housing has a length of between 10 millimetres and 40 millimetres, preferably between 10 millimetres and 30 millimetres, or most preferably between 14 millimetres and 20 millimetres.

[0134] Example Ex21 : A cartridge according to any preceding example, wherein the housing has a width of between 5 millimetres and 20 millimetres, preferably between 5 millimetres and 15 millimetres, or most preferably between 7 millimetres and 12 millimetres.

[0135] Example Ex22: A cartridge according to any preceding example, wherein the housing has a thickness of between 2 millimetres and 15 millimetres, preferably between 3 millimetres and 10 millimetres, or most preferably between 4 millimetres and 8 millimetres.

[0136] Example Ex23: An aerosol-generating system comprising a cartridge according to any of the preceding examples and an aerosol-generating device, the aerosol-generating device comprising: a power source; and control circuitry for controlling the supply of power from the power source to the heater.

[0137] Example Ex24: A method of manufacturing a cartridge for an aerosol-generating system, the method comprising: providing a housing defining a chamber for containing an aerosol-generating substrate.

[0138] Example Ex25: A method according to Example Ex24, further comprising providing the housing with a reflective surface facing an interior of the chamber.

[0139] Example Ex26: A method according to Example Ex24 or Ex25, further comprising providing a heating element for heating the aerosol-generating substrate, wherein at least a portion of the heating element extends into the chamber. Example Ex27: A method according to any of Examples Ex24 to Ex26, further comprising providing an aerosol-generating substrate within the chamber.

[0140] Example Ex27: A method according to any of Examples Ex25 to Ex27, wherein providing the housing with a reflective surface comprises depositing a reflective coating on an inner wall of the housing.

[0141] Example Ex28: A method according to Example Ex27, wherein the reflective surface is deposited using a deposition process selected from one or more of the following: physical vapour deposition, chemical vapour deposition and sputtering.

[0142] Example Ex29: A method according to any of Examples Ex25 to Ex28, further comprising polishing the reflective surface.

[0143] Examples will now be further described with reference to the figures in which:

[0144] Figure 1 is a schematic perspective view of a cartridge according to an example of the present disclosure.

[0145] Figure 2 is a schematic cross-sectional view of the cartridge of Figure 1.

[0146] Figures 3A and 3B are schematic perspective views showing part of a housing of a cartridge showing two different reflective surfaces according to examples of the present disclosure.

[0147] Figure 4 is a schematic cross-sectional view of the cartridge of Figure 1 showing heat transfer within the cartridge.

[0148] Figure 5 is a schematic cross-sectional view of an aerosol-generating system according to an example of the present disclosure comprising the cartridge of Figure 1 and an aerosol-generating device.

[0149] Figure 6 is a flow chart of a method of manufacturing a cartridge for an aerosolgenerating system according to an example of the present disclosure.

[0150] It will be appreciated that at least some of the figures in the present application are schematic and have been simplified for the purposes of clarity. Consequently, some features may have been omitted and the features are not necessarily drawn to scale.

[0151] Referring to Figures 1 and 2, there is shown a schematic perspective view and a schematic cross-sectional view respectively of a cartridge 10 for use with an aerosolgenerating device (not shown). The cartridge 10 comprises a housing 12, a heating element 14 and an aerosol-generating substrate 16. The housing 12 defines a chamber 18 containing the aerosol-generating substrate 16.

[0152] The cartridge 10 comprises a proximal end 20 and a distal end 22. The housing 12 comprises a side wall 24 circumscribing the chamber 18. The side wall 24 extends parallel to a longitudinal axis A-A of the cartridge 10 between the proximal 20 and distal 22 ends of the cartridge 10. An inner surface 24a of the side wall 24, that is, the surface of the side wall 24 facing the interior of the chamber 18, comprises a reflective surface 25. The reflective surface 25 can be provided in a number of different ways, as discussed below with respect to Figures 3A and 3B. The side wall 24 is made from a low thermal conductivity metal such as stainless steel. The reflective surface 24a has an emissivity of less than 0.1.

[0153] The housing 12 further comprises a first housing end section arranged at the proximal end 20 of the cartridge 10 and a second housing end section arranged at the distal end 22 of the cartridge 10. In this example, the first housing end section comprises a proximal end plug 28 that is inserted into an opening 32 defined by the inner surface of the side wall 24 at the proximal end 20 of the cartridge 10. Furthermore, the second housing end section comprises a distal end plug 30 that is inserted into an opening 34 defined by the inner end surface of the side wall 24 at the distal end 22 of the cartridge. However, it will be appreciated that the first 28 and second 30 housing end sections may have a different construction to that shown in Figure 2, for example, at least one of the first 28 and second 30 housing end sections may be integral to the side wall 24. The side wall 24 and proximal 28 and distal 30 end plugs define the chamber 18.

[0154] The cartridge 10 comprises a plurality of air inlets 36, which extend through the distal end plug 30 in a direction parallel to the longitudinal axis A-A of the cartridge 10. The cartridge 10 further comprises a plurality of aerosol outlets 38, which extend through the proximal end plug 28 in a direction parallel to the longitudinal axis A-A of the cartridge 10. The plurality of air inlets 36 are in fluid communication with the plurality of aerosol outlets 38. An airflow pathway extends between the plurality of air inlets 36 and the plurality of aerosol outlets 38 through the chamber 18 and through the aerosol-generating substrate 16. Figure 2 shows the cartridge 10 having four air inlets 36 and four aerosol outlets 38. However, it will be appreciated that the cartridge 10 can have any suitable number of air inlets and aerosol outlets and that the dimensions, shape and number of the air inlets and aerosol outlets can be adapted depending on the characteristics desired of the cartridge 10, for example, the amount of aerosol to be produced or the desired resistance to draw (RTD).

[0155] The heating element 14 is configured to heat the aerosol-generating substrate 16 to generate an aerosol. The heating element 14 is a resistive heating element, which is configured to generate heat upon application of a voltage across the heating element 14. In the example cartridge 10 of Figure 2, the aerosol-generating substrate 16 is a solid, tobaccobased aerosol-generating substrate and the heating element 14 is embedded in the aerosolgenerating substrate 16. The heating element 14 is mounted on the distal end plug 30 and extends into the chamber 18. The heating element 14 has a serpentine shape comprising a plurality of segments that extend parallel to the longitudinal axis A-A of the cartridge 10. The heating element 14 is a self-supporting track and is substantially or entirely planar, with the plane of the heating element 14 extending across the width of the cartridge 10.

[0156] The end portions of the heating element 14 comprise electrical contacts 40 which are arranged to connect the heating element 14 to a power source. The electrical contacts 40 are electrically connected to electrically conductive vias 42 which pass through the thickness of the distal end plug 30 and form corresponding electrical contacts at the distal end of the cartridge 10 by which an electrical connection can be made to the heating element 14.

[0157] Figures 3A and 3B show examples of different ways in which the housing of the cartridge 10 of Figures 1 and 2 can be provided with a reflective surface facing an interior of the chamber. Figure 3A shows part of the housing 12 of the cartridge 10. In particular, it shows part of the side wall 24 of the housing 12 of the cartridge 10. A reflective surface is provided on the inner surface 24a of the side wall 24 by a reflector component 27. The reflector component 27 comprises a thin sheet of material no more than 1.0 millimetre thick which is folded or otherwise shaped to conform to the inner surface 24a of the side wall 24. The reflector component 27 has a inner reflective surface 25a that is arranged to face an interior of the chamber of the cartridge. The reflector component 27 may comprise a metallic or ceramic material in which the inner surface is polished to form the reflective surface 25a. Alternatively, the reflector component 27 may comprise a metallic or ceramic layer or coating on its inner surface that is polished to form the reflective surface 25a, as discussed further below. The reflector component 27 is inserted into the side wall 24 of housing 12 in the direction of arrow C in Figure 3A and held in place by a suitable fastening means.

[0158] Figure 3B shows part of the side wall 24 of the housing 12 of the cartridge 10. In the example of Figure 3B, a reflective surface is provided on the inner surface 24a of the side wall 24 by a reflective coating 25b. In particular, the inner surface 24a of the side wall 24a is coated with a material and provided with a surface finish that is configured to maximize infrared (IR) reflectivity. This helps to provide efficient heat retention within the chamber of the cartridge. The inventors have found that suitable materials for the reflective coating 25b include highly polished metals such as aluminium or silver-based compounds, as well as high-temperature reflective ceramics. These materials provide a combination of high reflectivity in the IR spectrum and low emissivity, typically under 0.1 , which makes them highly effective in redirecting thermal energy back into the chamber.

[0159] The following examples describes coatings that the inventors have found effective for providing a reflective surface on an inner surface of the housing:

[0160] Polished Aluminium Coating

[0161] Aluminium has been found to have good reflective properties in the IR spectrum, with a reflectivity rate that can exceed 95% when polished to a mirror-like finish. It effectively reflects infrared radiation back toward the interior of the chamber of the cartridge, minimizing heat loss to the outer surfaces. Additionally, aluminium possesses natural oxidation resistance and its thermal stability make it durable under high-temperature cycling. This helps to provide the cartridge with consistent performance over time.

[0162] Silver-Based Coating

[0163] Silver has been found to provide good reflectivity across a wide range of wavelengths, including the IR spectrum, with reflectivity often above 98%. Silver-based coatings can be applied using techniques such as sputtering or physical vapor deposition (PVD), resulting in a thin, highly reflective layer that does not add significant bulk to the cartridge. The reflectivity of silver enhances the containment of thermal energy within the chamber, optimizing the cartridge’s internal temperature stability. Silver has also been found to be effective at maintaining reflectivity at higher temperatures, making it a suitable choice for cartridges that undergo repeated heating cycles.

[0164] High-Temperature Reflective Ceramic Coatings

[0165] The inventors have found that reflective ceramics can be engineered to withstand very high temperatures while maintaining strong IR reflectivity. Suitable ceramics include zirconia, alumina and titanium nitride. These ceramics are highly resistant to thermal degradation and provide consistent reflectivity, even in high-temperature environments. High-temperature reflective ceramics can be applied using deposition techniques, such as chemical vapor deposition (CVD), which helps to provide a uniform, durable layer that can withstand repeated heating and cooling. The ceramic coating’s low emissivity and high reflectivity make it especially effective in retaining thermal energy and reducing conductive heat transfer to the cartridge’s outer walls.

[0166] Surface finish has also been found to be an important factor in providing an effective reflective surface on an inner surface of the housing of the cartridge. The reflective coating is applied with a smooth and polished finish to improve thermal efficiency and enhance reflectivity. A polished surface finish helps to achieve effective infrared (IR) reflectivity because it minimizes microscopic surface irregularities that could scatter heat and diminish the coating's reflective properties. By reducing surface roughness to a minimal level, the smooth, polished finish helps to redirect infrared radiation uniformly and efficiently back into the interior of the chamber of the cartridge.

[0167] The reflective surface has a surface roughness of less than 0.20 micrometres Ra, which is equivalent to a smooth, mirror-like surface. Such a surface finish increases the IR reflectivity of the reflective by maximizing specular reflection. In other words, when the infrared radiation encounters a polished surface, it reflects predictably in a controlled direction, as opposed to scattering, which can lead to inefficient thermal containment. Surface irregularities, even at a microscopic level, can disrupt the path of infrared radiation, causing scattering and unintended heat loss from the chamber of the cartridge. By using precise machining or finishing processes, such as electropolishing or controlled abrasion, these surface irregularities can be reduced. Providing the reflective coating with a continuous, uniform surface helps to reduce diffuse reflection and enhances specular reflectivity.

[0168] This controlled reflection reduces the amount of heat escaping to the outer walls of the cartridge so that more thermal energy is retained within the interior of chamber of the cartridge. Furthermore, it assists in providing a stable internal temperature within the chamber and also reduces the amount of energy needed to maintain the interior of the chamber at the aerosol generation temperature, which enhances energy efficiency. This contributes to the overall thermal management and energy efficiency of the cartridge and aerosol-generating device.

[0169] Figure 4 is a schematic cross-sectional view of the cartridge 10 of Figure 1 showing heat transfer (depicted by arrows D and E in Figure 4) within the chamber 18 of the cartridge 10. As illustrated by arrows D, heat is generated and emitted by the heating element 14 and travels outwards through the aerosol-generating substrate (not shown) surrounding the heating element 14 heating the aerosol-generating substrate and producing an aerosol. The heat continues to travel outwards through the chamber 18 until it impinges on the reflective surface 25 arranged on the inner surface 24a of the side wall 24 of the housing 12 of the cartridge 10. At which point, the reflective surface 25 reflects the majority of the heat back into the interior of chamber 18, as illustrated by arrows E. Therefore, the majority of the heat that reaches the housing 12 of the cartridge 10 is reflected off the reflective surface 25 and retained within the chamber 18.

[0170] In contrast, a conventional cartridge without a reflective surface or with a more emissive surface, would allow heat to be transferred through the walls of the housing resulting in hot spots being formed on the external surface of the cartridge, which could make the cartridge uncomfortable or unsafe to handle.

[0171] The reflective surface 25 of cartridge 10 provides a passive insulation effect by continually redirecting heat within the chamber 18. Each time thermal radiation encounters the reflective surface 25, it is redirected inward rather than absorbed or conducted outward. This reflective trapping mechanism effectively insulates the chamber 18 without the need for bulky insulating materials, allowing the cartridge design to remain compact while benefiting from enhanced thermal containment. This passive insulation effect is particularly advantageous in cartridges for use in aerosol-generating device, which require a relatively high internal temperature without excessive heat dissipation to the surroundings. The cartridge 10 of the present disclosure not only provides a cooler outer casing of the cartridge 10, allowing safe removal by the consumer, but also enhances the efficiency of aerosol production due to the improved thermal retention and the maintenance of controlled high temperatures withing the chamber 18. Additionally, the cartridge 10 is more energy efficient, as less energy is required to maintain these high internal temperatures.

[0172] Figure 5 is a schematic cross-sectional view of an aerosol-generating system 200 comprising the cartridge 10 of Figure 1 and an aerosol-generating device 100. The aerosolgenerating device 100 comprises a device cavity 110 and a mouthpiece 112. The device cavity 110 is defined by a device housing 150. The cartridge 10 is configured to be received in the device cavity 110 of the aerosol-generating device 100.

[0173] The mouthpiece 112 is disposed at a proximal end of the aerosol-generating device 100 and is configured to move between an open position and a closed position. When the mouthpiece 112 is in the open position, the cartridge 10 can be inserted into or removed from the device cavity 110. When the mouthpiece 112 is in the closed position, the cartridge 10 is secured within the aerosol-generating device 100. In Figure 5, the mouthpiece 112 is shown in the closed position.

[0174] The aerosol-generating device 100 comprises a device air inlet 108, a device aerosol outlet 109, a power supply 130, and a controller 140. The device air inlet 108 is disposed at a distal end of the aerosol-generating device 100 and the device aerosol outlet 109 is arranged in the mouthpiece 112. The device air inlet 108 is in fluid communication with the plurality of air inlets (not shown) of the cartridge 10 and the device aerosol outlet 109 is in fluid communication with the plurality of aerosol outlets (not shown) of the cartridge 10. Therefore, an airflow pathway extends between the device air inlet 108 and device aerosol outlet 109, which pathway passes through the cartridge 10 to entrain generated aerosol.

[0175] The cartridge 10 and the aerosol-generating device 100 are configured such that the electrical contacts (not shown) of the cartridge 10 electrically connect to corresponding electrical contacts of the aerosol-generating device 100. The electrical contacts of the aerosolgenerating device 100 are electrically connected to the power supply 130, such that power can be supplied from the power supply 130 to the heating element (not shown) of the cartridge 10. In this example, the power supply 130 is in the form of a battery, for example, a rechargeable lithium ion battery.

[0176] The controller 140 is electrically connected to the power supply 130. The controller 140 is configured to control the supply of power from the power supply 130 to the heating element of the cartridge 10. In particular, the controller 140 controls whether the heating element is on or off and the temperature of the heating element.

[0177] In use, a consumer inserts a cartridge 10 into the device cavity 110 of the aerosol- generating device 100 and activates the device. This causes the heating element of the cartridge 10 to start heating the aerosol-generating substrate contained within the cartridge 10. When the heating element and aerosol-generating substrate are at the aerosolization temperature of the aerosol-generating substrate, the consumer can take a puff on the aerosolgenerating system 200. This draws air in through the device air inlet 108, through the device cavity 110 and into the plurality of air inlets 110 of the cartridge 10. The air passes through the aerosol-generating substrate surrounding the heating element in the cartridge 10, which entrains aerosol in the moving airflow. The aerosol laden airflow passes out of the cartridge 10 via the plurality of aerosol outlets of the cartridge 10, and is delivered to the device aerosol outlet 109 in the mouthpiece 112, where it passes into the mouth of the consumer.

[0178] Figure 6 shows a flow chart of a method 300 of manufacturing a cartridge for an aerosol-generating system. The method 300 comprises a first step S1 providing a housing for the cartridge, in which the housing defines a chamber for containing an aerosol-generating substrate. At least a portion of the housing may be formed from a low thermal conductivity metal such as stainless steel.

[0179] In a second step S2, the method 300 comprises providing the housing with a reflective surface facing an interior of the chamber. There are numerous ways in which this can be done, as discussed further below.

[0180] In a third step S3, the method 300 comprises providing a heating element for heating the aerosol-generating substrate. At least a portion of the heating element is arranged such that it extends into the chamber.

[0181] And in a fourth step S4, the method 300 comprises providing an aerosol-generating substrate within the chamber.

[0182] The step S2 of providing the housing with a reflective surface can be done by providing a reflector component on an inner surface of the housing, in which the reflector component comprises the reflective surface. The reflective surface of the reflector component can be formed from a polished metallic or ceramic layer.

[0183] Alternatively, the step S2 of providing the housing with a reflective surface can be done by providing a reflective coating on an inner surface of the housing such that the reflective coating forms the reflective surface. The application of the reflective coating to the inner surface of the housing can be achieved using manufacturing techniques such as physical vapor deposition (PVD), sputtering, or chemical vapor deposition (CVD). These methods were chosen by the inventors due to their ability to produce thin, uniform coatings with high reflectivity in the infrared (IR) spectrum. Each of these deposition processes can be tailored to achieve a precisely controlled thickness of the reflective layer, which maximizes thermal containment efficiency while ensuring long-term durability under repeated heating cycles. PVD deposits a solid material, such as aluminium or silver, as a thin film in a vacuum environment. The key advantages of this deposition method are strong adhesion of the material to the housing, high thermal stability and precise thickness control. This deposition method is suitable for producing a reflective layer that withstands repeated heating cycles.

[0184] Sputtering ejects atoms at a relatively low temperature from a target material to form a uniform coating on the housing’s inner surface. The key advantages of this deposition method are uniform coverage and the ability to cover complex shapes. Furthermore, this method does not distort base material. This deposition method is suitable for cartridges with housings having intricate geometries that require consistent reflectivity.

[0185] CVD uses reactive gases to bond reflective material chemically to the housing inner surface. The key advantages of this deposition method are high durability, strong chemical bonding between the deposited material and underlying housing, thermal degradation resistance and it scalability. This deposition method is suitable for high-volume production where cartridges require good performance in high-temperature applications.

[0186] Each of these deposition methods, that is, PVD, sputtering and CVD, allows for precision control of the thickness of the reflective coating, for example, micron or sub-micron level control of the thickness of the reflective coating can be achieved. This helps to achieve effective infrared reflectivity. The inventors have found that thin coatings, for example, ranging from 5 to 50 nanometres, can be sufficient to achieve high levels of IR reflectivity. This provides efficient heat retention without adding unnecessary mass or bulk to the housing walls of the cartridge. The ability to precisely control the coating thickness also ensures uniform heat reflection across the entire surface, which contributes to consistent thermal containment within the cartridge.

[0187] For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 5 percent (5%) of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

Claims1. A cartridge for an aerosol-generating device, the cartridge comprising: a housing defining a chamber containing an aerosol-generating substrate; a heating element for heating the aerosol-generating substrate, at least a portion of the heating element extending into the chamber; wherein the housing comprises a reflective surface facing an interior of the chamber; wherein the aerosol-generating substrate comprises a solid aerosol-generating substrate.

2. A cartridge according to claim 1 , wherein the reflective surface has an emissivity of less than 0.2.

3. A cartridge according to claim 1 or 2, wherein the housing comprises a reflector component arranged on an inner surface of the housing, the reflector component comprising the reflective surface.

4. A cartridge according to claim 3, wherein the reflector component comprises a polished metallic or ceramic layer that forms the reflective surface.

5. A cartridge according to claim 1 or 2, wherein the housing comprising a reflective coating arranged on an inner surface of the housing, the reflective coating forming the reflective surface.

6. A cartridge according to claim 5, wherein the reflective coating comprises a metal, metal alloy or ceramic.

7. A cartridge according to claim 6, wherein the reflective coating comprises a material selected from one or more of aluminium, silver, gold, zirconia, alumina, titanium nitride, chromium, and stainless steel.

8. A cartridge according to any of claims 5 to 7, wherein the reflective coating is polished and has a surface roughness of less than 0.20 micrometres Ra.

9. A cartridge according to any of claims 5 to 8, wherein the reflective coating has a thickness of between 5 nanometres and 200 nanometres.

10. A cartridge according to any preceding claim, wherein the housing comprises: a first housing end section; a second housing end section; and a side wall circumscribing the chamber and extending between the first and second housing end sections; wherein the reflective surface is arranged on an inner surface of the side wall.

11. A cartridge according to claim 10, wherein the heating element is mounted on the second housing end section at a distal end of the housing.

12. A cartridge according to claim 10 or 11 , wherein the heating element is an internal heating element and is embedded in the aerosol-generating substrate.

13. A cartridge according to any of claims 10 to 12, wherein the heating element is substantially planar and is oriented so that a plane of the heating element extends across the width of the cartridge.

14. A cartridge according to any of claims 10 to 13, wherein the heating element comprises a plurality of segments extending parallel to the longitudinal axis of the cartridge.

15. An aerosol-generating system comprising a cartridge according to any of the preceding claims and an aerosol-generating device, the aerosol-generating device comprising: a power source; and control circuitry for controlling the supply of power from the power source to the heater.

16. A method of manufacturing a cartridge for an aerosol-generating system, the method comprising: providing a housing defining a chamber for containing an aerosol-generating substrate; providing the housing with a reflective surface facing an interior of the chamber; providing a heating element for heating the aerosol-generating substrate, wherein at least a portion of the heating element extends into the chamber; and providing an aerosol-generating substrate within the chamber, the aerosol-generating substrate comprising a solid aerosol-generating substrate.

17. A method according to claim 16, wherein providing the housing with a reflective surfacecomprises depositing a reflective coating on an inner wall of the housing using a deposition process selected from one or more of the following: physical vapour deposition, chemical vapour deposition and sputtering.

18. A method according to any of claims 16 or 17, further comprising polishing the reflective surface.

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