Heater assembly for aerosol generation system

Abstract

The present invention provides a heater assembly for an aerosol generation system, including a liquid storage section for holding a liquid aerosol-forming substrate. [Solution] The heater assembly comprises an electric heater (30) having at least one heating element (36) for heating a liquid aerosol-forming substrate to form an aerosol, and a capillary body (22) for transporting the liquid aerosol-forming substrate from the liquid storage portion of the aerosol generating system to at least one heating element. The at least one heating element is formed of an electrically conductive material that adheres directly to the porous outer surface (32) of the capillary body. A cartridge (20) for use in an aerosol generating system and a method for manufacturing such a cartridge are also provided.

Description

Technical Field

[0001] The present invention relates to an aerosol generation system and a heater assembly for an aerosol generation system, the heater assembly comprising an electric heater suitable for vaporizing an aerosol-forming substrate. In particular, the present invention relates to a portable aerosol generation system, such as an electrically operated smoking system. Aspects of the present invention relate to a heater assembly for an aerosol generation system, a cartridge for an aerosol generation system, and a method of manufacturing such cartridges.

Background Art

[0002] One type of aerosol generation system is an electrically operated smoking system. A portable electrically operated smoking system is well known, which consists of a device part comprising a battery and a control electronic circuit, a cartridge part comprising a supply of an aerosol-forming substrate, and an electrically operated vaporizer. A cartridge comprising both a supply of an aerosol-forming substrate and a vaporizer is sometimes referred to as a "cartomizer". The vaporizer is generally a heater assembly. In some well-known examples, the aerosol-forming substrate is a vaporizer comprising a liquid aerosol-forming substrate and a coil of heater wire wound around an elongate wick immersed in the liquid aerosol-forming substrate. The cartridge part generally includes not only a supply of an aerosol-forming substrate and an electrically operated heater assembly, but also a mouthpiece through which the user draws an aerosol into the mouth during use.

[0003]

[0004] While this type of system may be effective for aerosol generation, it can be difficult to manufacture in a low-cost and repeatable manner. Furthermore, the core and coil assemblies, along with their associated electrical connections, can be fragile and difficult to handle.

[0005] It is desirable to provide heater assemblies for aerosol generating systems, such as handheld electrically operated smoking systems, that improve aerosol properties. It is even more desirable to provide more robust heater assemblies for aerosol generating systems that improve aerosol properties, and to provide cartridges for aerosol generating systems. [Overview of the Initiative]

[0006] According to a first aspect of the present invention, a heater assembly for use in an aerosol generating system having a liquid storage portion for holding a liquid aerosol forming substrate is provided, the heater assembly comprising: an electric heater having at least one heating element for heating a liquid aerosol forming substrate for aerosol formation; and a capillary body for transporting the liquid aerosol forming substrate from the liquid storage portion of the aerosol generating system to at least one heating element, wherein the at least one heating element is formed of an electrically conductive material that adheres directly to the porous outer surface of the capillary body.

[0007] Advantageously, the contact between at least one heating element and the capillary body can be improved by directly attaching an electrically conductive material to the porous outer surface of the capillary body to form at least one heating element. This is done, for example, by compensating for surface roughness or unevenness on the outer surface of the capillary body. This can, in other words, allow for a reduction in many or severe "hot spots" on the outer surface of the capillary body that may occur if the heating element does not contact the capillary body over its length. Thus, this can result in improved aerosol properties. The improved contact between at least one heating element and the capillary body can also allow for improved delivery of the liquid aerosol-forming substrate to the heating element.

[0008] In addition, the heating element is attached to the capillary tube body by forming the heating element by directly adhering an electrically conductive material onto the porous outer surface of the capillary tube body. This reduces the risk of contact loss between the heating element and the capillary tube body caused by deformation of the heating element due to thermal pressure induced, for example, during assembly or use. It also allows for the use of heater geometric arrangements or layouts that would not be possible in other ways. For example, more complex or thinner filament geometric arrangements or layouts of heating elements can be realized using pre-formed electric heaters.

[0009] As used herein, the term “capillary body” means one component of a heater assembly that can transport a liquid aerosol-forming substrate to an electric heater by capillary action.

[0010] As used herein, the term “electrically conductive material” means 1 × 10 -2 This shows materials with resistivity less than Ωm.

[0011] As used herein, the term “adhering” means being added as a coating onto the outer surface of the capillary body, in the form of a liquid, plasma, or vapor that is later condensed or aggregated to form a heating element, rather than simply being placed on the capillary body as a solid or a pre-formed compound.

[0012] As used herein, the term “directly adhering” means that an electrically conductive material adheres to the porous outer surface of the capillary body such that at least one heating element is in direct contact with the porous outer surface.

[0013] As used herein, the term "porous" means formed of a material that is permeable to a liquid aerosol-forming substrate and allows the liquid aerosol-forming substrate to move through it.

[0014] In certain preferred embodiments, the electrically conductive material of at least one heating element is at least partially dispersed within the porous outer surface of the capillary body.

[0015] As used herein, the term “radiated onto the porous outer surface” means that the electrically conductive material is incorporated into or mixed with the material of the porous outer surface at the interface between the electrically conductive material and the capillary body, for example, by extending into the pores of the porous outer surface.

[0016] Using this configuration, the contact area between at least one heating element and the capillary body can be further improved, which leads to a further reduction in numerous or severe "hot spots" on the outer surface of the capillary body and improved aerosol properties. Furthermore, by extending into the porous outer surface of the capillary body, the area of ​​contact between at least one heating element and the capillary body is increased. This can result in further improved delivery of the liquid aerosol-forming substrate to the heating element by the capillary body and improved heating of the liquid aerosol-forming substrate by the heating element. It can also improve adhesion between the heating element and the capillary body, further reducing the risk of loss of contact between the heating element and the capillary body caused by deformation of the heating element due to thermal pressure induced, for example, during assembly or use.

[0017] Thus, an electrically conductive material on which at least one heating element is formed may be attached to the porous outer surface by any suitable method. For example, the electrically conductive material may be attached to the porous outer surface of the capillary body as a liquid by using a supply pipette or syringe, or by using a transport device with a fine tip such as a needle.

[0018] In some embodiments, at least one heating element includes a printable electrically conductive material printed on the porous outer surface of the capillary tube body. In such embodiments, any suitable well-known printing technique can be used, such as one or more of screen printing, gravure printing, flexographic printing, and inkjet printing. Such printing processes may be particularly suitable for high-speed manufacturing processes.

[0019] Alternatively, an electrically conductive material on which at least one heat-generating element is formed may be deposited onto the porous outer surface of the capillary body by one or more vacuum deposition processes, such as evaporation deposition and sputtering.

[0020] At least one heating element may be formed of any suitable electrical conductive material. In certain preferred embodiments, the electrical conductive material includes one or more of metals, electrical conductive polymers, and electrical conductive ceramics.

[0021] Suitable electrically conductive metals include aluminum, silver, nickel, gold, platinum, copper, tungsten, and their alloys. In some embodiments, the electrically conductive material comprises metal powder suspended in an adhesive such as epoxy resin. In one embodiment, the electrically conductive material comprises silver-added epoxy.

[0022] Suitable electrically conductive polymers include PEDOT (poly(3,4-ethylenedioxythiophene)), PSS (poly(p-phenylene sulfide)), PEDOT:PSS (a mixture of both PEDOT and PSS), PANI (polyaniline), PPY (poly(pyrrole)s), PPV (poly(p-phenylene vinylene)), or any combination thereof.

[0023] Suitable examples of electrically conductive ceramics include ITO (indium tin oxide), SLT (lanthanum-doped strontium titanate), SYT (yttrium-doped strontium titanate), or any combination thereof.

[0024] The electrically conductive material may further contain one or more additives selected from the group consisting of solvents, curing agents, adhesion promoters, surfactants, viscosity reducers, and aggregation inhibitors. Such additives may be used before application of the electrically conductive material to the porous outer surface of the capillary body for purposes such as promoting adhesion of the electrically conductive material to the porous outer surface of the capillary body, increasing the amount of electrically conductive material radiated into the porous outer surface of the capillary body, reducing the time required to position the electrically conductive material, increasing the degree of adhesion between the electrically conductive material and the capillary body, or reducing the amount of aggregation of suspended particles such as metal particles or metal powder.

[0025] The heating profile of the electric heater can be substantially constant across the porous outer surface of the capillary body.

[0026] In some embodiments, at least one heating element is arranged such that its temperature profile varies across the electric heater.

[0027] Advantageously, by varying the temperature profile of at least one heating element, the heat generated by the electric heater across the outer surface of the capillary body can be adjusted according to the characteristics of the cartridge (e.g., according to the airflow characteristics of the cartridge).

[0028] In certain preferred embodiments, at least one heating element is arranged such that the electric heater generates more heat across the periphery of the porous outer surface. This enables the electric heater to compensate for heat loss from the periphery of the outer surface (e.g., heat loss by heat conduction), which results in a more uniform temperature across the porous outer surface.

[0029] The heating profile of the electric heater may vary across the porous outer surface by changing the distribution of at least one heating element across the porous outer surface. For example, the heating profile of the electric heater may increase towards the center of the porous outer surface by increasing the distribution density of at least one heating element towards the center of the porous outer surface. As used herein, the term "distribution density" means the proportion of the porous outer surface to which the electrical conductive material of at least one heating element adheres. For example, a 50 percent distribution within a particular area of the porous outer surface indicates that the electrical conductive material adheres to 50 percent of that area and does not adhere to the remaining 50 percent of that area.

[0030] The heating profile of the electric heater may vary across the porous outer surface by changing the resistance of the heating element across the porous outer surface.

[0031] In some embodiments, the resistance of at least one heating element is reduced toward the center of the porous outer surface to alter the heating profile of the electric heater across the porous outer surface. Using this configuration, the electric heater generates more heat toward the periphery of the porous outer surface of the capillary body. This allows the electric heater to compensate for heat loss from the periphery of the outer surface of the capillary body (e.g., heat loss due to heat conduction), which can result in a more uniform temperature across the porous outer surface of the capillary body.

[0032] The resistance of at least one heating element can be varied by using multiple heating elements formed of electrically conductive materials having different resistivity values. For example, the resistance of at least one heating element can be decreased toward the center of the porous outer surface by arranging multiple heating elements on the porous outer surface such that the resistivity of at least one heating element toward the periphery of the porous outer surface of the capillary body is greater than the resistivity of at least one heating element toward the center of the porous outer surface of the capillary body.

[0033] In some embodiments, the cross-sectional area of ​​at least one heating element is varied. This allows the temperature profile of at least one heating element to be adjusted according to the characteristics of the cartridge, since the resistance of at least one heating element is inversely proportional to its cross-sectional area. In such embodiments, at least one heating element may include a heating element having a cross-sectional area that varies along the length of the heating element. Alternatively, or additionally, at least one heating element may include a first heating element having a first cross-sectional area and a second heating element having a second cross-sectional area different from the first.

[0034] In certain preferred embodiments, the cross-sectional area of ​​at least one heating element increases toward the center of the porous outer surface. This results in more heat being generated from at least one heating element toward the periphery of the porous outer surface. This allows the electric heater to compensate for heat loss from the periphery of the outer surface (e.g., heat loss by conduction), which results in a more uniform temperature across the porous outer surface.

[0035] The cross-sectional area of ​​at least one heating element can be changed by changing the thickness of at least one heating element, the width of at least one heating element, or both the thickness and width of at least one heating element.

[0036] As used herein, the terms “vary,” “varies,” “differ,” “differs,” and “different” mean deviations beyond standard manufacturing tolerances, in particular values ​​that deviate from each other by at least 5 percent.

[0037] As used herein, the term "thickness" means the dimensions of the heating element in a direction perpendicular to the porous outer surface of the capillary body and perpendicular to the length of the heating element.

[0038] As used herein, the term "width" means the dimensions of the heating element in a direction parallel to the porous outer surface of the capillary body and perpendicular to the length of the heating element.

[0039] In any of the embodiments described above, adjacent portions of at least one heating element may be arranged with gaps to define a plurality of openings within the electric heater, where the size of the openings varies to change the temperature profile of the electric heater. In such embodiments, the at least one heating element may include a plurality of heating elements arranged with gaps to define a plurality of openings. Alternatively, or additionally, the at least one heating element may include one or more heating elements that form a nonlinear shape such that adjacent portions of one or more heating elements are arranged with gaps to define a plurality of openings.

[0040] In certain preferred embodiments, the size of the opening decreases towards the periphery of the porous surface of the capillary body.

[0041] This results in more heat being generated from at least one heating element toward the periphery of the porous outer surface. This allows the electric heater to compensate for heat loss from the periphery of the outer surface (e.g., heat loss by conduction), which results in a more uniform temperature across the porous outer surface. This configuration also allows more aerosol to pass through the electric heater in the central part of the porous outer surface, which can be advantageous in heater assemblies where the central part of the porous surface is the most important vaporization area. For example, the average size of the openings in the periphery of the porous outer surface of the capillary body is at least 10 percent smaller, preferably at least 20 percent smaller, and more preferably at least 30 percent smaller than the average size of the openings on the outside of the periphery of the porous outer surface of the capillary body. The periphery may have an area smaller than about 80 percent of the total area of ​​the porous outer surface of the capillary body, preferably less than about 60 percent, more preferably less than about 40 percent, and most preferably less than about 20 percent.

[0042] An electric heater may have a single heating element. Alternatively, an electric heater may have multiple heating elements connected in series or in parallel. In such embodiments, the multiple heating elements may be formed from the same electrically conductive material.

[0043] Alternatively, the electric heater may comprise at least one first heating element formed of a first electrically conductive material and at least one second heating element formed of a second electrically conductive material different from the first, wherein the first and second electrically conductive materials are directly attached to the porous outer surface of the capillary body. Preferably, the resistivity of the first electrically conductive material is different from that of the second electrically conductive material.

[0044] Advantageously, this allows the temperature profile of at least one heating element, and consequently the heat generated by the electric heater across the outer surface of the capillary body, to be adjusted according to the desired characteristics.

[0045] In certain preferred embodiments, the electric heater includes a plurality of heating elements formed of an electrically conductive material having different resistivity values. In such embodiments, the plurality of heating elements may be arranged such that the resistivity of at least one heating element toward the periphery of the porous outer surface of the capillary body is greater than the resistivity of at least one heating element toward the center of the porous outer surface of the capillary body. By using this configuration, the electric heater generates more heat toward the periphery of the porous outer surface of the capillary body. This allows the electric heater to compensate for heat loss from the periphery of the outer surface of the capillary body (e.g., heat loss by heat conduction), which can result in a more uniform temperature across the porous outer surface of the capillary body.

[0046] An electric heater may include multiple heating elements formed from multiple different electrically conductive materials. In some embodiments, the electric heater includes multiple heating elements, each formed from a different electrically conductive material.

[0047] One or more of the heating elements may be made of a material with resistance that changes significantly with temperature, such as an iron-aluminum alloy. This allows for measurement of the resistance of the heating element used to determine the temperature or temperature change. This can be used for control in a smoke detection system.

[0048] The electric heater may include first and second conductive contact portions that electrically contact at least one heating element. In such embodiments, the first and second conductive contact portions may be formed of an electrically conductive material that adheres directly to the porous outer surface of the capillary body.

[0049] In some embodiments, the overall electric heater is formed of one or more electrically conductive materials that adhere substantially directly to the porous outer surface of the capillary body.

[0050] The electrical resistance of the electric heater is preferably 0.3 to 4 ohms. More preferably, the electrical resistance of the electric heater is 0.5 to 3 ohms, and even more preferably, it is about 1 ohm.

[0051] If an electric heater has a conductive contact portion for contacting at least one heating element, the electrical resistance of at least one heating element is preferably at least one order of magnitude greater than the electrical resistance of the contact portion, and more preferably at least two orders of magnitude greater. This localizes the heat generated by passing current from the electric heater to at least one heating element. When a cartridge is used in an aerosol generation system where the power source is a battery, it is generally advantageous for the electric heater to have low overall resistance. Minimizing parasitic losses between the electrical contact and the heating element is also desirable to minimize parasitic power loss. A low-resistance, high-current system allows high power to be supplied to the electric heater. This allows the heater to quickly heat the heating element to the desired temperature.

[0052] The conductive contact portion may be directly fixed to at least one heating element. Alternatively, the conductive contact portion may be integrated with at least one heating element. Providing a conductive contact portion that forms part of at least one heating element enables reliable and simple connection to the power supply of an electric heater.

[0053] The capillary body may be of other types or shapes, such as a capillary core or capillary tube. In a preferred embodiment, the capillary body includes capillary material. The capillary material may include any suitable material or combination of materials. The capillary body may also include a single capillary material.

[0054] In some embodiments, the capillary body comprises a first capillary material and a second capillary material, wherein at least one heating element is formed of an electrically conductive material that adheres directly to the porous outer surface of the first capillary material, the second capillary material is in contact with the first capillary material and separated from it by an electric heater and a gap between them, and the first capillary material has a higher thermal decomposition temperature than the second capillary material. The first capillary material effectively acts as a spacer separating at least one heating element from the second capillary material so that the second capillary material is not exposed to temperatures exceeding its thermal decomposition temperature. In some embodiments, the thermal decomposition temperature of the first capillary material is at least 160°C, and preferably at least 250°C.

[0055] As used herein, “thermal decomposition temperature” means the temperature at which a material begins to decompose and loses mass by producing gaseous by-products.

[0056] The second capillary material may advantageously occupy a larger volume than the first capillary material and may hold more aerosol-forming substrates than the first capillary material. The second capillary material may have better core performance than the first capillary material. The second capillary material may be less expensive or have higher filling capacity than the first capillary material. The second capillary material may be polypropylene.

[0057] The first capillary material may be separated from the second capillary material by at least 1.5 mm from the electric heater, and is preferably 1.5 mm to 2 mm in thickness to provide a sufficient temperature drop across the first capillary material.

[0058] If the capillary body contains capillary material, the capillary material may have a fibrous or spongy structure. Preferably, the capillary material contains a bundle of capillaries. For example, the capillary material may contain multiple fibers or threads or other microtubules. The fibers or threads may generally be aligned to move the liquid to the heater. Alternatively, the capillary material may contain a spongy or foamy material. The structure of the capillary material forms multiple small holes or tubes through which the liquid can be transported by capillary action. The capillary material (one or more) may contain any suitable material or combination of materials. Examples of suitable materials include spongy or foamy materials, ceramic or graphite-based materials in the form of fibers or sintered powders, foamy metal or plastic materials, and fibrous materials made of spun or extruded fibers (such as cellulose acetate, polyester, or bonded polyolefins, polyethylene, terylene or polypropylene fibers, nylon fibers or ceramics). Capillary materials may have any suitable capillary action and porosity for use with different liquid physical properties. Liquids have physical properties, including but not limited to viscosity, surface tension, density, thermal conductivity, boiling point, and vapor pressure, that allow them to be transported through capillary devices by capillary action.

[0059] According to a second aspect of the present invention, a cartridge for use in an aerosol generating system is provided, the cartridge comprising a liquid storage portion and a heater assembly for holding a liquid aerosol forming substrate according to any of the embodiments described above.

[0060] In an alternative embodiment, the heater assembly may be provided as an integrated component of the aerosol generating system, rather than as a component forming a cartridge for use in the aerosol generating system.

[0061] The liquid storage portion of the cartridge may be provided by a capillary body. For example, the capillary body may be made of a high-retention capillary material that forms the liquid storage portion of the cartridge. Alternatively, the liquid storage portion and the capillary body may be separate components of the cartridge.

[0062] When the liquid storage portion and the capillary body are separate components of the cartridge, in certain embodiments the capillary body includes a first end extending into the liquid storage portion for contact with the liquid therein and a porous second end opposite the first end, wherein at least one heating element is formed of an electrically conductive material directly attached to the second end of the capillary body. Alternatively, the first end of the capillary body may be outside the liquid storage portion, and the capillary body may include at least one other porous surface for contact with the liquid in the liquid storage portion. For example, the capillary body may include one or more porous sidewalls for contact with the liquid in the liquid storage portion and through which a liquid aerosol-forming substrate moves from the liquid storage portion to an electric heater.

[0063] The liquid storage section may include a housing for holding a liquid aerosol-forming substrate, the housing having an opening, and the capillary body being positioned such that an electric heater extends across the opening.

[0064] The cartridge may comprise a liquid storage section including a housing for holding a liquid aerosol-forming substrate, the housing having an opening. The housing may be rigid and impermeable to fluid. As used herein, “rigid housing” means a self-supporting housing. The capillary body may be a capillary material contained within the housing of the storage section.

[0065] The housing may include two or more different capillary materials, where a first capillary material in contact with at least one heating element has a higher thermal decomposition temperature, and a second capillary material in contact with the first capillary material but not with at least one heating element has a lower thermal decomposition temperature. The first capillary material effectively acts as a spacer, separating the heating elements from the second capillary material so that the second capillary material is not exposed to temperatures above its thermal decomposition temperature. As used herein, “thermal decomposition temperature” means the temperature at which a material begins to decompose and loses mass by generating gaseous byproducts. The second capillary material may advantageously occupy a larger volume than the first capillary material and may hold more aerosol-forming substrates than the first capillary material. The second capillary material may have better core performance than the first capillary material. The second capillary material may be less expensive or have higher packing capacity than the first capillary material. The second capillary material may be polypropylene.

[0066] If the liquid storage portion comprises a housing with an opening, at least one heating element extends across the entire length dimension of the opening in the housing. The width dimension is the dimension perpendicular to the length dimension in the plane of the opening. Preferably, at least one heating element has a width narrower than the width of the opening in the housing. Preferably, the electric heater is spaced between the periphery of the opening and the heating element. The width of at least one heating element may be smaller than the width of the opening in at least the area of ​​the opening. The width of at least one heating element may be smaller than the width of the opening in all areas of the opening. The width of at least one heating element may be less than 90 percent of the width of the opening in the housing, for example, less than 50 percent, for example, less than 30 percent, for example, less than 25 percent. The area of ​​at least one heating element may be less than 90 percent of the area of ​​the opening in the housing, for example, less than 50 percent, for example, less than 30 percent, for example, less than 25 percent. The area of ​​at least one heating element may be, for example, 10 percent to 50 percent of the area of ​​the opening, and preferably 15 to 25 percent of the area of ​​the opening. The area ratio of the opening to the total area of ​​the electric heater, specifically the opening area of ​​at least one heating element, is preferably about 25 percent to about 56 percent. The opening may be of any suitable shape. For example, the opening may be circular, square, or rectangular. The area of ​​the opening may be small, preferably about 25 square mm or less. The distance between the heating element and the periphery of the opening is preferably such that thermal contact is significantly reduced. The distance between the heating element and the periphery of the opening may be 25 μm to 40 μm.

[0067] Preferably, at least one heating element is positioned such that its physical contact area with the liquid storage portion is reduced compared to the case where the heating element of an electric heater is in contact with the entire periphery of the liquid storage portion. Preferably, at least one heating element does not directly contact the periphery of the liquid storage portion. In this way, thermal contact with the liquid storage portion is reduced, and heat loss to the liquid storage portion and further adjacent elements of an aerosol generating system in which the cartridge is used is also reduced.

[0068] While we do not wish to be bound by any particular theory, it is thought that by spacing the heating element away from the liquid storage area, less heat will be transferred to the liquid storage area, thereby improving heating efficiency and, consequently, aerosol generation efficiency.

[0069] An electric heater may comprise a single heating element or multiple heating elements connected in parallel or in series. If the electric heater comprises at least a first conductive contact portion and a second conductive contact portion for contacting at least one heating element, the first and second conductive contact portions may be arranged such that the first contact portion contacts the first heating element and the second contact portion contacts the last heating element in the series. Additional contact portions may be provided to allow all heating elements to be connected in series.

[0070] When an electric heater includes multiple heating elements, the heating elements may be arranged substantially parallel to each other spatially. It is preferable that there are gaps between the heating elements. While we do not wish to be bound by any particular theory, it is thought that spacing the heating elements apart may provide more efficient heating. By appropriately spacing the heating elements, more uniform heating may be achieved, for example, across the area of ​​an opening, compared to when a single heating element of the same area is used.

[0071] If an electric heater includes multiple heating elements, at least one of the heating elements may include a first material, and at least one of the other heating elements may include a second material different from the first material. This may be beneficial for electrical or mechanical reasons. For example, one or more of the heating elements may be made of a material with resistance that changes significantly with temperature, such as an iron-aluminum alloy. This allows for the measurement of the resistance of the heating element used to determine the temperature or temperature change. This can be used in a smoke detection system to control the heater temperature to keep it within a desired temperature range.

[0072] At least one heating element may comprise an array of conductive filaments extending along the length of at least one heating element, with a plurality of openings defined by gaps between the conductive filaments. In such embodiments, the size of the plurality of openings may be varied by increasing or decreasing the size of the gaps between adjacent filaments. This may be achieved by varying the width of the conductive filaments, or by varying the spacing between adjacent filaments, or by varying both the width of the conductive filaments and the spacing between adjacent filaments.

[0073] As used herein, the term “filament” refers to an electrical path arranged between two electrical contacts. The filament may optionally branch into several paths or filaments, or several electrical paths may merge into one. The filament may have a round, square, flat, or any other cross-sectional shape. In a preferred embodiment, the filament has a substantially planar cross-section. The filament may be arranged in a straight or curved manner.

[0074] The conductive filament may be substantially planar.

[0075] As used herein, "substantially planar" preferably means formed within a single plane and not wound around or adapted to, for example, a curved shape or other non-planar shape. Planar electric heaters are easy to handle during manufacturing and are given a robust structure.

[0076] The liquid aerosol-forming substrate is a liquid substrate that has the ability to release volatile compounds capable of forming aerosols. The volatile compounds may also be released by heating the aerosol-forming substrate.

[0077] The aerosol-forming substrate is a liquid. The aerosol-forming substrate may contain plant-derived materials. The aerosol-forming substrate may contain tobacco. The aerosol-forming substrate may contain tobacco-containing materials that contain volatile tobacco-flavored compounds released from the aerosol-forming substrate upon heating. Alternatively, the aerosol-forming substrate may contain non-tobacco-containing materials. The aerosol-forming substrate may contain homogenized plant-derived materials. The aerosol-forming substrate may contain homogenized tobacco materials. The aerosol-forming substrate may contain at least one aerosol-forming compound. The aerosol-forming compound is any suitable known compound or mixture of compounds that facilitates the formation of a dense and stable aerosol during use and is substantially resistant to thermal decomposition at the operating temperature of the system. Suitable aerosol-forming materials are well known in the industry and include, but are not limited to, polyhydric alcohols (such as triethylene glycol, 1,3-butanediol, and glycerin), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, or triacetate), and aliphatic esters of monocarboxylic acids, dicarboxylic acids, or polycarboxylic acids (such as dimethyl dodecanediol and dimethyl tetradecanediol). Preferred aerosol-forming materials are polyhydric alcohols or mixtures thereof (such as triethylene glycol, 1,3-butanediol, and glycerin (most preferred)). The aerosol-forming substrate may also contain other additives and components (such as flavorings).

[0078] According to a third aspect of the present invention, an aerosol generating system is provided comprising an aerosol generator and a cartridge according to any of the embodiments described above, wherein the cartridge is detachably coupled to the aerosol generator, and the aerosol generator includes a power supply for an electric heater.

[0079] As used herein, "removably coupled" to the device means that the cartridge and the device can be coupled to and separated from each other without significant damage to either the device or the cartridge.

[0080] The cartridge is replaceable after use. Since the cartridge holds the aerosol-forming substrate and electric heater, the electric heater is also replaced periodically to ensure optimal vaporization conditions are maintained even after prolonged use of the main unit.

[0081] The aerosol generation system may further include an electric heater and an electrical circuit connected to a power source, the electrical circuit configured to monitor the electrical resistance of the electric heater and control the power supply from the power source to the electric heater depending on the monitored electrical resistance. For example, the electrical circuit may be configured to monitor the electrical resistance of one or more heating elements. By monitoring the temperature of the electric heater, the system can prevent overheating or underheating of the electric heater and ensure that optimal vaporization conditions are provided.

[0082] The electrical circuit may include a microprocessor, which may be a programmable microprocessor, a microcontroller, an application-specific integrated circuit (ASIC), or other electronic circuit capable of providing control. The electrical circuit may include further electronic components. The electrical circuit may be configured to regulate the power supply to the heater. Power may be supplied to the electric heater continuously after the system is started, or intermittently, such as with each smoke extraction. Power may be supplied to the electric heater in the form of current pulses.

[0083] The aerosol generator includes a power source for the cartridge's electric heater. The power source may be a battery in the device, such as a lithium iron phosphate battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have a capacity to store enough energy for one or more smoking experiences. For example, the power source may have a capacity sufficient to continuously generate aerosol for about 6 minutes, or a multiple of 6 minutes, corresponding to the typical time it takes to smoke one conventional cigarette. In another embodiment, the power source may have a capacity sufficient to allow a predetermined number of puffs or discontinuous activations of the heater.

[0084] The liquid storage section may be positioned above the first side of the electric heater, and the airflow channel may be positioned above the electric heater on the opposite side of the storage section so that the airflow passing through the electric heater mixes in the vaporized aerosol-forming substrate.

[0085] The system may be an electrically operated smoking system. The system may be a handheld aerosol generating system. The aerosol generating system may be comparable in size to a conventional cigar or cigarette. The overall length of the smoking system may be approximately 30 mm to approximately 150 mm. The outer diameter of the smoking system may be approximately 5 mm to approximately 30 mm.

[0086] A fourth aspect of the present invention provides a method for manufacturing a cartridge for use in an aerosol generating system, the method comprising the steps of: providing a liquid storage portion for holding a liquid aerosol forming substrate; providing a capillary body having a porous outer surface; forming an electric heating element by directly attaching an electrically conductive material to the porous outer surface of the capillary body; filling the liquid storage portion with the liquid aerosol forming substrate; and connecting the capillary body to the liquid storage portion so that the liquid aerosol forming substrate contained in the liquid storage portion is transported from the liquid storage portion to the electric heating element by the capillary body.

[0087] The liquid storage portion of the cartridge may be provided by a capillary body. For example, the capillary body may be made of a high-retention capillary material that forms the liquid storage portion of the cartridge. Alternatively, the liquid storage portion and the capillary body may be separate components of the cartridge.

[0088] When the liquid storage portion and the capillary body are separate components of the cartridge, in certain embodiments the capillary body includes a first end extending into the liquid storage portion for contact with the liquid therein and a porous second end opposite the first end, wherein at least one heating element is formed of an electrically conductive material directly attached to the second end of the capillary body. Alternatively, the first end of the capillary body may be outside the liquid storage portion, and the capillary body may include at least one other porous surface for contact with the liquid in the liquid storage portion. For example, the capillary body may include one or more porous sidewalls for contact with the liquid in the liquid storage portion and through which a liquid aerosol-forming substrate moves from the liquid storage portion to an electric heater.

[0089] The liquid storage section may include a housing for holding a liquid aerosol-forming substrate, the housing having an opening, and the capillary body being positioned such that an electric heater extends across the opening.

[0090] Thus, the electrically conductive material on which at least one heating element is formed may be attached to the porous outer surface by any suitable method. For example, the electrically conductive material may be attached to the porous outer surface of the capillary body as a liquid by using a supply pipette or syringe, or by using a transport device with a fine tip such as a needle. In certain embodiments, the electrically conductive material is attached directly to the porous outer surface of the capillary body by one or more vacuum deposition methods such as evaporation deposition and sputtering.

[0091] In a preferred embodiment, the electrically conductive material is attached by printing an electrically conductive material that is directly printable onto the porous outer surface of the capillary tube body. In such embodiments, any suitable well-known printing technique may be used. For example, one or more of screen printing, gravure printing, flexographic printing, and inkjet printing may be used. Such printing processes may be advantageous, especially when high-speed manufacturing processes are used.

[0092] The printable electrically conductive material may include any suitable electrically conductive material. In certain preferred embodiments, the electrically conductive material includes one or more of metals, electrically conductive polymers, and electrically conductive ceramics.

[0093] Suitable electrically conductive metals include aluminum, silver, nickel, gold, platinum, copper, tungsten, and their alloys. In some embodiments, the electrically conductive material comprises metal powder suspended in an adhesive such as epoxy resin. In one embodiment, the electrically conductive material comprises silver-added epoxy.

[0094] Suitable electrically conductive polymers include PEDOT (poly(3,4-ethylenedioxythiophene)), PSS (poly(p-phenylene sulfide)), PEDOT:PSS (a mixture of both PEDOT and PSS), PANI (polyaniline), PPY (poly(pyrrole)s), PPV (poly(p-phenylene vinylene)), or any combination thereof.

[0095] Suitable examples of electrically conductive ceramics include ITO (indium tin oxide), SLT (lanthanum-doped strontium titanate), SYT (yttrium-doped strontium titanate), or any combination thereof.

[0096] The printable electrically conductive material may further contain one or more additives selected from the group consisting of solvents, curing agents, adhesion promoters, surfactants, viscosity reducers, and aggregation inhibitors. Such additives may be used before application of the electrically conductive material to the porous outer surface of the capillary body, for example, to promote adhesion of the electrically conductive material to the porous outer surface of the capillary body, to increase the amount of electrically conductive material radiated into the porous outer surface of the capillary body, to reduce the time required to position the electrically conductive material, to increase the degree of adhesion between the electrically conductive material and the capillary body, or to reduce the amount of aggregation of suspended particles such as metal particles or metal powder.

[0097] When printed on the porous outer surface of a capillary tube body, the printed electrically conductive material can be cured by any suitable well-known method to form at least one heating element. For example, the printed electrically conductive material can be cured by exposure to heat or ultraviolet light. Alternatively, or additionally, the printed electrically conductive material can be cured by sintering or by inducing a chemical reaction. In one particular embodiment, the printed electrically conductive material contains copper and is cured to form at least one heating element by inducing a chemical reaction.

[0098] In certain embodiments, the method further includes the step of heat-treating an electrically conductive material to increase the conductivity of at least one heating element. In one particular embodiment, the electrically conductive material includes a conductive ceramic such as indium tin oxide, and the method further includes the step of heat-treating the electrically conductive material to grow fine crystal grains of the ceramic, thereby increasing its conductivity.

[0099] Features described in relation to one or more embodiments may be equally applicable to other embodiments of the present invention. In particular, features described in relation to the heater assembly of the first embodiment may be equally applicable to the cartridge of the second embodiment, and vice versa. Features described in relation to the heater assembly of the first embodiment or the cartridge of the second embodiment may be equally applicable to the aerosol generating system of the third embodiment or the manufacturing method of the fourth embodiment. Herein, embodiments of the present invention will be described, for illustrative purposes only, with reference to the following accompanying drawings. [Brief explanation of the drawing]

[0100] [Figure 1A] Figure 1A is a schematic diagram of a system incorporating a cartridge according to an embodiment of the present invention. [Figure 1B] Figure 1B is a schematic diagram of a system incorporating a cartridge according to an embodiment of the present invention. [Figure 1C]Figure 1C is a schematic diagram of a system incorporating a cartridge according to an embodiment of the present invention. [Figure 1D] Figure 1D is a schematic diagram of a system incorporating a cartridge according to an embodiment of the present invention. [Figure 2] Figure 2 is an exploded view of the cartridge of the system shown in Figure 1. [Figure 3A] Figure 3A shows an embodiment of the first heater assembly. [Figure 3B] Figure 3B shows an example of the second heater assembly. [Figure 3C] Figure 3C shows an example of the third heater assembly. [Figure 3D] Figure 3D shows an embodiment of the fourth heater assembly. [Figure 3E] Figure 3E shows an example of the fifth heater assembly. [Figure 4] Figure 4 shows graphs of temperature as a function of distance across the outer surface of the capillary body for the arrangements shown in Figures 3A and 3E. [Modes for carrying out the invention]

[0101] Figures 1A to 1D are schematic diagrams of an aerosol generating system including a cartridge according to an embodiment of the present invention. Figure 1A is a schematic diagram of the aerosol generating device 10, or main unit, and a separate cartridge 20, which together form the aerosol generating system. In this example, the aerosol generating system is an electrically operated smoking system.

[0102] Cartridge 20 contains an aerosol-forming substrate and is configured to be received in a recess 18 within the device. Cartridge 20 should be replaceable by the user when the aerosol-forming substrate provided in the cartridge is consumed. Figure 1A shows cartridge 20 immediately before insertion into the device, and arrow 1 in Figure 1A indicates the direction of cartridge insertion.

[0103] The aerosol generator 10 is portable and comparable in size to a conventional cigar or cigarette. The device 10 includes a main body 11 and a mouthpiece 12. The main body 11 includes a battery 14 (such as a lithium iron phosphate battery), a control electronic circuit 16, and a recess 18. The mouthpiece 12 is connected to the main body 11 by a hinged connector 21 and can move between an open position shown in Figures 1A to 1C and a closed position shown in Figure 1D. The mouthpiece 12 is positioned in the open position to allow insertion and removal of the cartridge 20, and is positioned in the closed position when the system is used for aerosol generation, as described below. The mouthpiece 12 has multiple air intake ports 13 and air outlet ports 15. When in use, the user inhales or sucks at the outlet ports to draw air from the air intake ports 13 through the mouthpiece 15, and then into the user's mouth or lungs. The internal baffle 17 is provided to force the airflow through the mouthpiece portion 12 to pass through the cartridge, as described below.

[0104] The recess 18 has a circular cross-section and is sized to receive the housing 24 of the cartridge 20. An electrical connector 19 is provided on the side of the recess 18 to provide an electrical connection between the control electronic circuit 16 and the battery 14 and the corresponding electrical contacts of the cartridge 20.

[0105] Figure 1B shows the system of Figure 1A with the cartridge inserted into the recess 18 and the cover 26 removed. In this position, the electrical connector is positioned relative to the electrical contacts on the cartridge, as described below.

[0106] Figure 1C shows the system of Figure 1B with the cover 26 completely removed and the mouthpiece portion 12 in the closed position.

[0107] Figure 1D shows the system of Figure 1C with the mouthpiece portion 12 in the closed position. The mouthpiece portion 12 is held in the closed position by a clasp mechanism (not shown). It will be apparent to those skilled in the art that other suitable mechanisms (such as a snap-on or magnetic closure) may be used to hold the mouthpiece in the closed position.

[0108] The mouthpiece portion 12 in the closed position keeps the cartridge electrically in contact with the electrical connector 19, ensuring good electrical connection during use regardless of the system's orientation. The mouthpiece portion 12 may include an annular elastic element that engages with the surface of the cartridge and is compressed between the rigid mouthpiece housing element and the cartridge when the mouthpiece portion 12 is in the closed position. This ensures that good electrical connection is maintained regardless of manufacturing tolerances.

[0109] Naturally, other mechanisms for maintaining a good electrical connection between the cartridge and the device may be employed in an alternative or additional manner. For example, the housing 24 of the cartridge 20 may be provided with threads or grooves (not shown) that engage with corresponding grooves or threads (not shown) formed in the wall of the recess 18. The threaded engagement between the cartridge and the device can be used not only for correct rotational alignment but also for holding the cartridge in the recess and ensuring a good electrical connection. The threaded connection may extend only half a turn or less of the cartridge, or only a few turns. In an alternative or additional manner, the electrical connector 19 may be biased to contact contacts on the cartridge.

[0110] Figure 2 is an exploded view of a cartridge 20 suitable for use in an aerosol generating system, for example, an aerosol generating system of the type shown in Figure 1. The cartridge 20 includes a generally circular cylindrical housing 24 having a size and shape selected to be received in a corresponding recess of the aerosol generating system, such as the recess 18 of the system in Figure 1, or to be mounted in an appropriate manner using other elements. The housing 24 has an open end and also includes an aerosol-forming substrate. In this embodiment, the aerosol-forming substrate is liquid, and the housing 24 further includes a capillary body 22 containing a capillary material immersed in the liquid aerosol-forming substrate. In this embodiment, the aerosol-forming substrate contains 39 wt percent glycerin, 39 wt percent propylene glycol, 20 wt percent water and flavoring agent, and 2 wt percent nicotine. The capillary material is a material that actively carries the liquid from one end to the other and may be made from any suitable material. In this embodiment, the capillary material is formed from polyester. In other embodiments, the aerosol-forming substrate may be solid.

[0111] The capillary material 22 has a porous outer surface 32 to which an electric heater 30 is fixed. The heater 30 includes a pair of electrical contacts 34 fixed to opposing sides of the porous outer surface 32, and a heating element 36 fixed to the outer surface 32 and the electrical contacts 34. In this example, the heater 30 comprises a single heating element 36 extending between the electrical contacts 34 and having a meandering or zigzag arrangement. However, it will be apparent to those skilled in the art that other arrangements of the heater may be used. For example, the heater may comprise a single heating element in a double helix shape, or a shape following a more complex meandering path, or a shape following a substantially linear path. Similarly, the heater may comprise multiple heating elements (e.g., multiple substantially parallel heating elements).

[0112] The electrical contacts 34 and heater element 36 are integrally formed from an electrically conductive material that is directly deposited as a liquid onto the porous outer surface 32 and then dried. Because the outer surface 32 is porous, the electrically conductive material dissipates into the outer surface 32 during deposition, so that the heater 30 is securely fixed to the capillary material 22 when the electrically conductive material dries. Dissipation of the electrically conductive material into the outer surface 32 also increases the contact area between the heating element 36 and the capillary material 22, thereby improving the efficiency of heat transfer from the heating element 36 to the capillary material 22.

[0113] The heater 30 is covered by a removable cover 26. The cover 26 comprises a liquid-impermeable plastic sheet that is bonded to the heater assembly but can be easily peeled off. Tabs are provided on the sides of the cover so that the user can grasp the cover 26 when peeling it off. Here, bonding is described as a method of securing the impermeable plastic sheet, but it will be apparent to those skilled in the art that other methods familiar to those skilled in the art, including heat sealing or ultrasonic welding, may also be used, as long as the cover 26 can be easily removed by the consumer.

[0114] It is understood that other cartridge designs are also possible. For example, the capillary material used with the cartridge may comprise two or more separate capillary materials, or the cartridge may include a tank for holding a free liquid storage section.

[0115] The heater filament of the heater element 36 is exposed through the opening 35 of the substrate 34 so that the vaporized aerosol-forming substrate can pass through the heater assembly and escape into the airflow.

[0116] During use, the cartridge 20 is placed within the aerosol generating system, and the heater assembly 30 is in contact with a power source provided within the aerosol generating system. An electronic circuit is provided to power the heater element 36 and vaporize the aerosol generating substrate. The vaporized aerosol-forming substrate can then escape into the airflow passing through the heater 30.

[0117] Figures 3A to 3E show first to fifth embodiments of the arrangement of the electric heater 30. In the first embodiment, as shown in Figure 3A, the heater 30 includes diametrically opposed electrical contacts 34 and a single heating element 36 connected to the electrical contacts 34 and extending between the electrical contacts 34 along a meandering or zigzag path. In the second embodiment, as shown in Figure 3B, the heater 30 includes diametrically opposed electrical contacts 34 and a single heating element 36 connected to the electrical contacts 34 and extending between the electrical contacts 34 along a double helix path. In the third embodiment, as shown in Figure 3C, the heater 30 includes diametrically opposed electrical contacts 34 and a single heating element 36 connected to the electrical contacts 34 and extending between the electrical contacts 34 along a winding path. In the fourth embodiment, as shown in Figure 3D, the heater 30 includes electrical contacts 34 facing each other in the diametrical direction and a plurality of heating elements 36 connected to the electrical contacts 34 and extending between the electrical contacts 34 along substantially parallel paths. In the fifth embodiment, as shown in Figure 3E, the heater 30 is substantially identical to the heater of the first embodiment shown in Figure 3A, except that the cross-sectional area of ​​the heating elements 36 varies across the porous outer surface 32 to change the heating profile of the heater 30 across the porous outer surface 32. In particular, the width of the heating elements 36 narrows towards the periphery of the outer surface 32 and widens towards the center of the porous outer surface 32. This results in a decrease in the amount of heat generated by the heating elements relative to the center of the porous outer surface 32 and an increase in the amount of heat generated by the heating elements relative to the periphery of the porous outer surface 32, compared to the arrangement shown in Figure 3A. This allows the electric heater to compensate for heat loss from the periphery of the outer surface (e.g., heat loss due to heat conduction) and lowers the temperature at the center of the porous outer surface. This results in a more uniform temperature across the porous outer surface, as will be explained below in relation to Figure 4.

[0118] Figure 4 shows graphs of temperature as a function of distance across the outer surface of the capillary body for the arrangements in Figures 3A and 3E, respectively. Curve A illustrates the temperature for the heater of the first embodiment in Figure 3A. Curve E illustrates the temperature for the heater of the fifth embodiment in Figure 3E. As shown by curve A, the temperature of the porous outer surface when using the heater of the first embodiment decreases towards the periphery and increases towards the center, forming a hot spot in a narrow area in the center of the heating element. As shown by curve E, the temperature of the porous outer surface when using the heater of the fifth embodiment is higher towards the periphery than the temperature of the porous outer surface when using the heater of the first embodiment. Additionally, as shown by curve E, the temperature at the center of the porous outer surface when using the heating element of the fifth embodiment is lower and extends over a wider area. Therefore, the temperature profile across the porous outer surface is more uniform for the heater of the fifth embodiment than for the heater of the first embodiment, particularly in the central region.

[0119] When the cartridge is assembled, the heating element 36 is in direct contact with the capillary material 22, so that the aerosol-forming substrate can be directly transported to the heater. In this example of the present invention, the aerosol-forming substrate is in contact with most, though not all, of the surface of each heating element 36 so that most of the heat generated by the heater assembly enters the aerosol-forming substrate directly. In contrast, in conventional core and coil heater assemblies, only a very small portion of the heater wire is in contact with the aerosol-forming substrate.

[0120] During use, the heater assembly is preferably operated by resistance heating, but may also be operated using other suitable heating processes such as induction heating. When the heater assembly is operated by resistance heating, current passes through the heater under the control of the control electronic circuit 16, heating the filament to a desired temperature range. The heating element(s) 36 have significantly higher electrical resistance than the electrical contacts 34 so that high temperatures are localized to the heating element. The system may be configured to generate heat by supplying current to the heater in response to user fume extraction, or it may be configured to generate heat continuously while the device is in the "on" state. Different materials for the elements may be suitable for different systems. For example, in a continuous heating system, a material with a relatively low specific heat capacity is suitable because it is compatible with low-current heating. In a system operated by fume extraction where heat is generated by short bursts using high-current pulses, a material with a high specific heat capacity may be more suitable.

[0121] In a system that operates by inhaling smoke, the device may include a smoke sensor configured to detect when the user inhales air through the mouthpiece. The smoke sensor (not shown) is connected to a control electronic circuit 16, which is configured to supply current to the heater 30 only when it is determined that the user is inhaling smoke from the device. Any suitable airflow sensor, such as a microphone, may be used as the smoke sensor.

[0122] In a possible embodiment, a change in the resistivity of at least one heating element may be used to detect a change in temperature. This can be used to adjust the power supplied to the heater so that it is reliably maintained within a desired temperature range. Rapid temperature changes may also be used as a means of detecting changes in the airflow passing through the heating element due to smoke extraction by the system user. One or more of the filaments may be dedicated temperature sensors and may be formed from a material with a suitable temperature resistance coefficient for that purpose, such as an iron-aluminum alloy, Ni-Cr, platinum, tungsten, or an alloy.

[0123] Figure 1D shows the airflow passing through the mouthpiece section when the system is in use. The mouthpiece section is molded integrally with the outer wall of the mouthpiece section and includes an internal baffle 17 that allows air to flow over the heater 30 above the cartridge, where the aerosol-forming substrate is vaporized, as air is drawn from the inlet 13 to the outlet 15. As the air passes through the heater assembly, the vaporized substrate is mixed into the airflow and cooled before exiting the outlet 15 to form an aerosol.

[0124] The described embodiment has a cartridge with a housing having a substantially circular cross-section, but it is of course possible to form a housing for a cartridge with other shapes, such as a rectangular or triangular cross-section. These housing shapes ensure a desirable orientation within a corresponding recess and ensure an electrical connection between the device and the cartridge.

[0125] Those skilled in the art will be able to devise other cartridge designs incorporating the heater assembly according to this disclosure. For example, the cartridge may include a mouthpiece portion and may have any desired shape. Furthermore, the heater according to this disclosure may be used in systems other than those already described (such as humidifiers, air fresheners, and other aerosol generating systems). [Examples]

[0126] Example 1 To form the heating element and electrical contacts of the heater, EpoTek (RTM) H20E, a silver-added epoxy conductive adhesive available from Epoxy Technology Inc. of Billerica Montana, USA, was manually dispersed by a needle tip onto the capillary body formed from Sterlitech GB140, a glass fiber capillary material available from Sterlitech Corporation of Kent, Washington, USA. To measure the heater, an Agilent N6705B programmable power supply was used to supply current to the heater for 3 seconds. The current was supplied at a voltage of 3.55V with a power of 4.3W. An infrared camera was used to record the temperature of the outer surface of the capillary body during the test procedure.

[0127] Example 2 To form the heating element and electrical contacts of the heater, EpoTek (RTM) H20E, a silver-added epoxy conductive adhesive available from Epoxy Technology Inc. of Billerica Montana, USA, was manually dispersed by a needle tip onto a capillary body formed from a porous ceramic capillary material with a pore size of 20 microns and a porosity of 40–45 percent. To measure the heater, an Agilent N6705B programmable power supply was used to supply current to the heater for 3 seconds. The current was supplied at a voltage of 3.55V with a power of 4.3W. The heater resistance was measured to be 2.3 ohms. An infrared camera was used to record the temperature of the outer surface of the capillary body during the test procedure, and the maximum temperature was found to be 185°C.

[0128] The exemplary embodiments described above are illustrative but not limiting. In light of the exemplary embodiments discussed above, other embodiments consistent with the exemplary embodiments will now be apparent to those skilled in the art.

Claims

1. A heater assembly for use in an aerosol generating system having a liquid storage portion for holding a liquid aerosol forming substrate, wherein the heater assembly is An electric heater having at least one heating element for heating the liquid aerosol-forming substrate to form an aerosol, The system comprises a capillary body for transporting the liquid aerosol-forming substrate from the liquid storage portion of the aerosol generating system to the at least one heating element, Herein, the heater assembly wherein the at least one heating element is made of an electrically conductive material that adheres directly to the porous outer surface of the capillary tube body.

2. The heater assembly according to claim 1, wherein the electrically conductive material of at least one heating element is at least partially radiated into the porous outer surface of the capillary body.

3. The heater assembly according to claim 1 or 2, wherein the at least one heating element includes a printable electrically conductive material printed on the porous outer surface of the capillary body.

4. The heater assembly according to any one of claims 1 to 3, wherein the electrically conductive material comprises one or more of a metal, an electrically conductive polymer, and an electrically conductive ceramic.

5. The heater assembly according to any one of claims 1 to 4, wherein the resistance of the at least one heating element decreases toward the center of the porous outer surface to change the heating profile of the electric heater across the porous outer surface.

6. The heater assembly according to any one of claims 1 to 5, wherein the cross-sectional area of ​​at least one heating element increases toward the center of the porous outer surface to change the heating profile of the electric heater.

7. The heater assembly according to any one of claims 1 to 6, wherein a gap is provided between adjacent portions of at least one heating element to define a plurality of openings within the electric heater, where the size of the openings is varied to change the heating profile of the electric heater.

8. The heater assembly according to any one of claims 1 to 7, wherein the electric heater comprises at least one heating element formed of a first electrically conductive material and at least one heating element formed of a second electrically conductive material different from the first electrically conductive material, and the first and second electrically conductive materials are directly attached to the porous outer surface of the capillary body.

9. The heater assembly according to any one of claims 1 to 8, wherein the electric heater comprises first and second conductive contact portions that electrically contact the at least one heating element, and the first and second conductive contact portions are formed of an electrically conductive material that adheres directly to the porous outer surface of the capillary body.

10. The heater assembly according to any one of claims 1 to 9, wherein the capillary body comprises a first capillary material and a second capillary material, the at least one heating element is formed of an electrically conductive material that adheres directly to the porous outer surface of the first capillary material, the second capillary material is in contact with the first capillary material and is separated from the heater assembly by a gap through the first capillary material, and the first capillary material has a higher thermal decomposition temperature than the second capillary material.

11. A cartridge for use in an aerosol generating system, wherein the cartridge comprises a liquid storage portion for holding a liquid aerosol forming substrate and a heater assembly according to any one of claims 1 to 10.

12. The cartridge according to claim 11, wherein the capillary body includes a first end extending into the liquid storage portion for contact with a liquid and a porous second end opposite to the first end, wherein the at least one heating element is formed of an electrically conductive material that is directly attached to the second end of the capillary body.

13. Aerosol generation system, Aerosol generator and The cartridge comprises the cartridge according to claim 11 or 12, An aerosol generating system in which the cartridge is detachably coupled to the aerosol generating device, and the aerosol generating device includes a power supply for the heater assembly.

14. The aerosol generating system according to claim 13, wherein the aerosol generating system is an electrically operated smoking system.

15. A method for manufacturing a cartridge for use in an aerosol generating system, wherein the method is A step of providing a liquid storage portion for holding a liquid aerosol forming substrate, A step of providing a capillary body having a porous outer surface, A step of forming an electrically heating element by directly attaching an electrically conductive material to the porous outer surface of the capillary tube body, The process involves filling the liquid storage portion with a liquid aerosol forming substrate, A method comprising the step of connecting the capillary body to the liquid storage portion such that the liquid aerosol-forming substrate contained in the liquid storage portion is transported from the liquid storage portion to the electric heating element by the capillary body.

16. The method according to claim 15, wherein the electrically conductive material is attached by printing an electrically conductive material that can be directly printed onto the porous outer surface of the capillary body.

17. The method according to claim 16, wherein the printable electrically conductive material comprises one or more additives selected from the group consisting of solvents, curing agents, adhesion promoters, surfactants, viscosity reducers, and aggregation inhibitors.

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