Heating assembly for an aerosol generating device

Abstract

The present invention relates to a heating assembly for an aerosol generating device. The heating assembly may include a first substrate layer that is an electrically insulating substrate layer. The heating assembly may further include a heating element disposed on the first substrate layer. The heating assembly may further include a second substrate layer that may be an electrically insulating substrate layer. The second substrate layer may be disposed to cover the heating element and the first substrate layer. The heating assembly may further include a temperature sensor. The temperature sensor may be disposed on the second substrate layer. The heating assembly may further include a third substrate layer that may be an electrically insulating substrate layer. The third substrate layer may be disposed to at least partially cover the temperature sensor and to cover the second substrate layer.

Description

[Technical Field]

[0001] The present invention relates to a heating assembly for an aerosol generating device. The present invention further relates to an aerosol generating device and a method for manufacturing the heating assembly. [Background technology]

[0002] It is known to provide aerosol-generating devices for producing inhalable vapors. Such devices may heat an aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate volatilize, without burning the aerosol-forming substrate. The aerosol-forming substrate may be provided as part of an aerosol-generating article. The aerosol-generating article may have a rod shape for insertion of the aerosol-generating article into a cavity (e.g., a heating chamber) of the aerosol-generating device. A heating assembly may be disposed in or around the heating chamber to heat the aerosol-forming substrate when the aerosol-generating article is inserted into the heating chamber of the aerosol-generating device. Summary of the Invention [Problem to be solved by the invention]

[0003] It would be desirable to have a heating assembly for an aerosol generating device that has improved reliability.It would be desirable to have a heating assembly for an aerosol generating device that has improved manufacturing quality.It would be desirable to have a heating assembly for an aerosol generating device that has improved robustness during manufacturing. [Brief explanation of the drawings]

[0004] [Figure 1] 1 shows a heating assembly. [Figure 2] 1 shows the layers that make up the heating assembly. [Figure 3] 1 shows the layers that make up the heating assembly, including the third insulating layer. [Figure 4] 1 shows different perspective views of the heating assembly, in particular the electrical connections. DETAILED DESCRIPTION OF THE INVENTION

[0005] According to one embodiment of the present invention, a heating assembly for an aerosol generating device is provided. The heating assembly may include a first substrate layer that is an electrically insulating substrate layer. The heating assembly may further include a heating element disposed on the first substrate layer. The heating assembly may further include a second substrate layer that may be an electrically insulating substrate layer. The second substrate layer may be disposed to cover the heating element and the first substrate layer. The heating assembly may further include a temperature sensor. The temperature sensor may be disposed on the second substrate layer. The heating assembly may further include a third substrate layer that may be an electrically insulating substrate layer. The third substrate layer may be disposed to at least partially cover the temperature sensor and to cover the second substrate layer.

[0006] According to one embodiment of the present invention, there is provided a heating assembly for an aerosol generating device. The heating assembly includes a first substrate layer that is an electrically insulating substrate layer. The heating assembly further includes a heating element disposed on the first substrate layer. The heating assembly further includes a second substrate layer that is an electrically insulating substrate layer. The second substrate layer is disposed to cover the heating element and the first substrate layer. The heating assembly further includes a temperature sensor. The temperature sensor is disposed on the second substrate layer. The heating assembly may further include a third substrate layer that is an electrically insulating substrate layer. The third substrate layer may be disposed to at least partially cover the temperature sensor and to cover the second substrate layer.

[0007] Providing a third substrate layer on top of the temperature sensor facilitates manufacturing. In particular, conventionally, it has been problematic for the temperature sensor to be placed on the adhesive layer of the second substrate layer. Adhesion between any of the layers discussed herein, particularly between the temperature sensor and the second substrate layer, can be created by an assembly process based on the application of pressure and high temperature (hot melt press). The press is applied on the temperature sensor, which is then placed on the adhesive layer. The problem is that because the adhesive layer is applied evenly over the surface of the second substrate layer and the temperature sensor occupies only a limited area, the press surface comes into contact with the adhesive layer, creating significant difficulties during the assembly process.

[0008] The proposed solution is to apply a third substrate layer over the temperature sensor to avoid contact between the press surface and the adhesive layer, which may have one or more openings so that the electrical contacts of the temperature sensor track can still be connected to the temperature sensor, as explained in more detail below.

[0009] The term "covering" or "covering" may mean that a first layer has substantially the same size as a second layer so that the first layer can be placed on the second layer such that the surface area of ​​the second layer facing the first layer is overlapped by the first layer. When the first layer is placed to cover the second layer, the surface size of the first layer may be at least 90% of the surface area of ​​the second layer, preferably at least 80% of the surface area of ​​the second layer, more preferably at least 70% of the surface area of ​​the second layer, and most preferably at least 60% of the surface area of ​​the second layer.

[0010] The heating element can be sandwiched between the first substrate layer and the second substrate layer. The heating element can cover only a portion of the surface of the first substrate layer. When the second substrate layer is disposed on the first substrate layer and the heating element, the second substrate layer preferably covers the heating element and the remaining portion of the surface of the first substrate layer on which the heating element is disposed and that is not covered by the heating element.

[0011] Similarly, the temperature sensor can be sandwiched between the second and third substrate layers. The temperature sensor can cover only a portion of the surface of the second substrate layer. When the third substrate layer is disposed over the second substrate layer and the temperature sensor, the third substrate layer preferably covers the temperature sensor and the remaining portion of the surface of the second substrate layer on which the temperature sensor is disposed and not covered by the temperature sensor.

[0012] In the final heating assembly, the heating element and temperature sensor are preferably located on opposing surfaces of the second substrate layer, such that the heating element is electrically insulated from the temperature sensor by the second substrate layer.

[0013] The heating element is protected by a first substrate layer and by a second substrate layer.

[0014] The temperature sensor is protected by a second substrate layer and by a third substrate layer.

[0015] The heating element may be a resistive heater. The heating element may comprise a heating track. The heating element may be a heating track. The heating track may be configured to generate heat. The heating track may be an electrical resistive heating track. The heating element may comprise electrical contacts for electrically contacting the heating track. The electrical contacts may be attached to the heating track by any known means, for example by soldering or welding. A first electrical contact may be attached to a first end of the heating track and a second electrical contact may be attached to a second end of the heating track. The first end of the heating track may be a proximal end of the heating track and the second end of the heating track may be a distal end of the heating track, or vice versa.

[0016] The heating track may be made of stainless steel. The heating track may be made of stainless steel about 50 μm thick. The heating track may preferably be made of stainless steel about 25 μm thick. The heating track may be made of Inconel about 50.8 μm thick. The heating track may be made of Inconel about 25.4 μm thick. The heating track may be made of copper about 35 μm thick. The heating track may be made of constantan about 25 μm thick. The heating track may be made of nickel about 12 μm thick. The heating track may be made of brass about 25 μm thick.

[0017] The heating elements, preferably heating tracks, may be printed onto the first substrate layer. The heating tracks may be photoprinted onto the substrate layer. The heating tracks may be chemically etched onto the substrate layer.

[0018] The term "heat track" includes a single heat track. The heating element or heat track may be printed on the first substrate layer.

[0019] The heating track may be centrally located on the first substrate layer. The heating track may have a bent shape. The heating track may have a curved shape. The heating track may have a zigzag shape. The heating track may have a serpentine shape.

[0020] The heating assembly can be rolled into a tubular shape. The heating track can be flat before the substrate layer is rolled into a tubular shape. The heating track or heating element can be flexible. The heating track or heating element can conform to the tubular shape of the substrate layer when it is rolled into a tubular shape.

[0021] The third substrate layer may include at least two openings. The two openings are provided to allow electrical contacts of the temperature sensor to make contact through the third substrate layer.

[0022] The two openings may be aligned such that the two contacts of the temperature sensor are not covered by the third substrate layer. The two openings may be located adjacent opposite ends of the third substrate layer. The two openings may correspond to the locations of the electrical contacts on the temperature sensor.

[0023] In addition to the two openings, an additional opening may be provided in the third substrate layer. The third opening may be centrally located in the third substrate layer. This third opening may improve the mechanical strength of the third substrate layer in this region. In particular, the central opening in the third substrate layer may strengthen the fixation of the electrical wires that contact the electrical contacts of the temperature sensor, since the electrical wires contact the adhesive layer underlying the second substrate layer in this region.

[0024] The electrical contacts of the temperature sensor may be attached to the temperature sensor by any known means, illustratively by soldering or welding. A first electrical contact may be attached to a first end of the temperature sensor, and a second electrical contact may be attached to a second end of the temperature sensor. The first end of the temperature sensor may be the proximal end of the temperature sensor, and the second end of the temperature sensor may be the distal end of the temperature sensor, or vice versa.

[0025] The temperature sensor may include a temperature sensor track.

[0026] The heating assembly may include a tube, preferably a metal tube, wrapped around or wound with a substrate layer. The metal tube is preferably a stainless steel tube. Alternatively, the tube may be a ceramic tube. The tube may define the tubular shape of the heating assembly. The outer diameter of the tube may correspond to the inner diameter of the first substrate layer after rolling the substrate layer.

[0027] The heating assembly may further include a heating chamber that conforms to the tubular shape of the heating assembly. The substrate layer may be rolled with the heating element and temperature sensor to fit the tube that forms the heating chamber. In this configuration, the first substrate layer may form the inner layer facing the tube, and the third substrate layer may be the outer layer. The first substrate layer may be adjacent to the metal tube that forms the innermost layer of the heating assembly.

[0028] The tube may be made of stainless steel. The tube may have a length of 10 mm to 35 mm, preferably 12 mm to 30 mm, preferably 13 mm to 22 mm. The tube may be hollow. The hollow tube may have an inner diameter of 4 mm to 9 mm, preferably 5 mm to 6 mm, or 6.8 mm to 7.5 mm, preferably about 5.35 mm or about 7.3 mm. The tube may have a thickness of 70 μm to 110 μm, preferably 80 μm to 100 μm, preferably about 90 μm. The tube may have a cylindrical cross section. The tube may have a circular cross section.

[0029] The length of the first substrate layer can be equal to or less than the circumference of the tube. The first substrate layer can completely wrap around the tube. The first substrate layer can be wrapped once around the tube so that the surface of the tube is covered by the first substrate layer after it has wrapped around the tube.

[0030] The tube of the heating chamber may have a thickness of 70 μm to 110 μm, preferably 80 μm to 100 μm, preferably about 90 μm.

[0031] The temperature sensor can be an NTC, Pt100, or preferably a Pt1000 temperature sensor. The temperature sensor can be attached to the second substrate layer by an adhesive layer. The temperature sensor can be photoprinted on the second substrate layer. Chemical etching can be used to form one or both of the heating element heating track and the temperature sensor track. The temperature sensor contacts can then be welded onto the temperature sensor track through the opening in the third substrate layer.

[0032] The temperature sensor may be disposed on the second substrate layer such that, when the heating assembly is wound, the temperature sensor may be located in an area corresponding to the center of the first substrate layer. By positioning the temperature sensor in this manner, the heating element may be mapped such that the temperature sensor is located adjacent to the hottest portion of the heating element. The hottest portion adjacent to the temperature sensor may be the center of the first substrate layer. The heating element may be located at the center of the first substrate layer. The temperature sensor may be located directly adjacent to the heating element, spaced from the heating element by the thickness of the second substrate layer.

[0033] One or more of the following additional layers may be provided: A first adhesive layer may be provided between the first substrate layer and the heating element; A second adhesive layer may be provided between the heating element and the second substrate layer; A third adhesive layer may be provided between the second adhesive layer and the temperature sensor. A fourth adhesive layer may be provided between the temperature sensor and the third substrate layer.

[0034] The first adhesive layer may facilitate attachment between the first substrate layer and the heating element. The first adhesive layer may further facilitate attachment between the first substrate layer and the second substrate layer in areas of the first substrate layer not covered by the heating element. The second adhesive layer may facilitate attachment between the heating element and the second substrate layer. The third adhesive layer may facilitate attachment between the second substrate layer and the temperature sensor. The third adhesive layer may further facilitate attachment between the second substrate layer and the third substrate layer in areas of the third adhesive layer not covered by the temperature sensor. The fourth adhesive layer may facilitate attachment between the temperature sensor and the third substrate layer.

[0035] One or more of the adhesive layers may have a thickness of from 2 μm to 10 μm, preferably from 3 μm to 7 μm, more preferably about 5 μm.

[0036] One or more of the adhesive layers may be a silicone-based adhesive layer. The adhesive layers may include one or both of a PEEK-based adhesive and an acrylic adhesive.

[0037] One or more of the first substrate layer, the second substrate layer, and the third substrate layer may comprise a polyamide or polyimide film. Any of the substrate layers may be made from a polyimide or polyamide. The substrate layers may be configured to withstand temperatures of 220°C to 320°C, preferably 240°C to 300°C, and preferably about 280°C. Any of the substrate layers may be made from Pyralux.

[0038] A heat shrink layer may be placed around the heating assembly.

[0039] The heat shrink layer can be disposed around the heating assembly when it is rolled into a tubular shape. The heat shrink layer can be configured to shrink when heated. The heat shrink layer can hold the heating assembly tightly together. The heat shrink layer can be configured to apply uniform inward pressure to the heating assembly. The heat shrink layer can improve contact between the tubing and one or both of the first substrate layer and the second substrate layer and the third substrate layer. The heat shrink layer can hold most or all of the components of the heating assembly tightly together. The heat shrink layer can be used in place of the glue or adhesive layer described herein. Alternatively, the heat shrink layer can be used in addition to the glue or adhesive layer described herein.

[0040] The thickness of the heat shrinkable layer can be between 100 μm and 300 μm, preferably about 180 μm.

[0041] The heat shrink layer may be made of PEEK. The heat shrink layer may be made of or include one or more of Teflon and PTFE.

[0042] One or more of the substrate layers may have a thickness of from 10 μm to 50 μm, preferably from 20 μm to 30 μm, more preferably about 25 μm.

[0043] The heating element, preferably when made from stainless steel, may have a thickness of 20 μm to 60 μm, preferably 30 μm to 50 μm, more preferably about 40 μm. The heating track, preferably when made from stainless steel, may have a thickness of 20 μm to 60 μm, preferably 30 μm to 50 μm, more preferably about 40 μm.

[0044] Surrounding the heat shrink layer may be provided an insulating layer, which is preferably made of aerogel.

[0045] The present invention further relates to an aerosol generating device comprising a heating assembly as described herein.

[0046] The aerosol-generating device may include a cavity for receiving the aerosol-generating article. The heating assembly may be positioned at least partially surrounding the cavity.

[0047] The sidewalls of the cavity may be formed from tubing as described herein, preferably stainless steel tubing, and the heating assembly may be mounted on the stainless steel tubing, or the tubing may be part of the heating assembly and may be mounted within the housing or inner frame of the aerosol generating device.

[0048] The present invention further relates to a method of manufacturing a heating assembly for an aerosol generating device, the method comprising: providing a first substrate layer, the first substrate layer being an electrically insulating substrate layer; disposing a heating element on the first substrate layer; disposing a second substrate layer overlying the heating element and the first substrate layer, the second substrate layer being an electrically insulating substrate layer; disposing a temperature sensor on the second substrate layer; disposing a third substrate layer at least partially covering the temperature sensor and overlying the second substrate layer, wherein the third substrate layer is an electrically insulating substrate layer.

[0049] The present invention further relates to a method of manufacturing a heating assembly for an aerosol generating device, the method comprising: providing a first substrate layer, the first substrate layer being an electrically insulating substrate layer; disposing a heating element on the first substrate layer; disposing a second substrate layer overlying the heating element and the first substrate layer, the second substrate layer being an electrically insulating substrate layer; disposing a temperature sensor on the second substrate layer; and disposing a third substrate layer at least partially covering the temperature sensor and overlying the second substrate layer, the third substrate layer being an electrically insulating substrate layer.

[0050] As used herein, the terms "upstream" and "downstream" are used to describe the relative location of a component or part of a component of an aerosol-generating device with respect to the direction of airflow through the aerosol-generating device during use. An aerosol-generating device according to the present invention has a proximal end through which the aerosol exits the device during use. The proximal end of an aerosol-generating device may also be referred to as the mouth end or downstream end. The mouth end is downstream of the distal end. The distal end of an aerosol-generating article may also be referred to as the upstream end. Components or parts of components of an aerosol-generating device may be described as being upstream or downstream of one another based on their relative location with respect to the airflow path of the aerosol-generating device.

[0051] In all aspects of the present disclosure, the heating element may comprise an electrically resistive material. Suitable electrically resistive materials include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, alloys, and composites made of ceramic and metallic materials. Such composites may comprise doped or undoped ceramics.

[0052] As described, in any of the aspects of the present disclosure, the heating element may comprise an external heating element, where "external" refers to the aerosol-forming substrate. The external heating element may take any suitable form. For example, the external heating element may take the form of one or more flexible heating foils or heating tracks on a dielectric substrate such as polyimide. The dielectric substrate is the substrate layer. The flexible heating foils or heating tracks may be shaped to fit the periphery of the heating chamber. Alternatively, the external heating element may take the form of a metal grid, a flexible printed circuit board, a molded-in circuit component (MID), a ceramic heater, a flexible carbon fiber heater, or may be formed using a coating technique such as plasma deposition on an appropriately shaped substrate layer. The external heating element may also be formed using a metal with a defined temperature-resistivity relationship. In such an exemplary device, the metal may be formed as a track between the first and second substrate layers. The external heating element thus formed may be used for both heating and temperature monitoring of the external heating element during operation.

[0053] The heating element advantageously heats the aerosol-forming substrate by means of conduction. Alternatively, heat from either an internal or external heating element may be conducted to the substrate by a thermally conductive element.

[0054] In operation, the aerosol-forming substrate may be completely contained within the aerosol-generating device, in which case the user may puff on the mouthpiece of the aerosol-generating device. Alternatively, in operation, the smoking article containing the aerosol-forming substrate may be partially contained within the aerosol-generating device, in which case the user may puff on the smoking article directly.

[0055] The heating element may be configured as an induction heating element. The induction heating element may comprise an induction coil and a susceptor. Generally, a susceptor is a material capable of generating heat when penetrated by an alternating magnetic field. According to the present invention, the susceptor may be conductive, magnetic, or both conductive and magnetic. The alternating magnetic field generated by one or several induction coils heats the susceptor, which then transfers heat to the aerosol-forming substrate so that an aerosol is formed. Heat transfer may be primarily by thermal conduction. Such heat transfer is best when the susceptor is in close thermal contact with the aerosol-forming substrate. When an induction heating element is employed, the induction heating element may be configured as an external heater as described herein. When the induction heating element is configured as an external heating element, the susceptor element is preferably configured as a cylindrical susceptor at least partially surrounding the heating chamber. The heating track described herein may be configured as a susceptor. The susceptor can be disposed between the first substrate layer and the second substrate layer. The second portion of the substrate layer can be surrounded by an induction coil. The susceptor and induction coil can be part of a heating assembly.

[0056] Preferably, the aerosol generating device includes a power supply configured to provide power to one or both of the heating element and the heating assembly. Preferably, the power supply includes a power source. Preferably, the power source is a battery, such as a lithium-ion battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for approximately six minutes, or a multiple of six minutes. In another example, the power source may have a capacity sufficient to allow a predetermined number of puffs, or discontinuous activation of the heating assembly.

[0057] The aerosol generating device may comprise control electronics. The control electronics may comprise a microcontroller. The microcontroller is preferably a programmable microcontroller. The electrical circuit may include further electronic components. The electrical circuit may be configured to regulate the supply of power to the heating assembly. Power may be supplied to the heating assembly continuously after activation of the system, or may be supplied intermittently (e.g., between puffs). Power may be supplied to the heating assembly in the form of pulses of current.

[0058] The control electronics may include a printed circuit board. The control electronics may be configured as a printed circuit board.

[0059] The temperature sensor may be electrically connected to the control electronics. The length of the electrical connection between the temperature sensor and the control electronics may be longer than the distance between the temperature sensor and the control electronics. This may have the beneficial effect of preventing detrimental effects on the electrical contact between the temperature sensor and the control electronics due to thermal expansion of the contact during operation of the aerosol generating device. The electrical connection is preferably configured as an electrical wire.

[0060] Similarly, the length of the electrical connection between the heating element and the control electronics may be longer than the distance between the heating element and the control electronics, which can have the beneficial effect of preventing detrimental effects on the electrical contacts between the heating element and the control electronics due to thermal expansion of the contacts during operation of the aerosol generating device. The electrical connection is preferably configured as an electrical wire.

[0061] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing a volatile compound capable of forming an aerosol. The volatile compound can be released by heating or burning the aerosol-forming substrate. As an alternative to heating or burning, in some cases, the volatile compound can be released by a chemical reaction or by mechanical stimulation such as ultrasound. The aerosol-forming substrate can be solid or liquid, or can contain both solid and liquid components. The aerosol-forming substrate can be part of an aerosol-generating article.

[0062] As used herein, the term "aerosol-generating article" refers to an article that includes an aerosol-forming substrate capable of emitting a volatile compound that can form an aerosol. The aerosol-generating article may be disposable.

[0063] As used herein, the term "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-generating device may interact with one or both of an aerosol-generating article including an aerosol-forming substrate and a cartridge including an aerosol-forming substrate. In some examples, the aerosol-generating device may heat the aerosol-forming substrate to facilitate release of volatile compounds from the substrate. An electrically operated aerosol-generating device may include an atomizer, such as an electric heater, for heating the aerosol-forming substrate to form an aerosol.

[0064] As used herein, the term "aerosol-generating system" refers to the combination of an aerosol-generating device with an aerosol-forming substrate. When the aerosol-forming substrate forms part of an aerosol-generating article, the aerosol-generating system refers to the combination of an aerosol-generating device with an aerosol-generating article. In an aerosol-generating system, the aerosol-forming substrate and the aerosol-generating device work together to generate an aerosol.

[0065] Features described with respect to one embodiment may equally apply to other embodiments of the invention.

[0066] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:

[0067] 1 shows a heating assembly 10. The heating assembly 10 comprises a stainless steel tube 12. The stainless steel tube 12 forms the inner layer of the heating assembly 10. The stainless steel tube 12 is tubular. The stainless steel tube 12 forms the heating chamber 14 such that an aerosol-generating article comprising an aerosol-forming substrate can be placed within the heating chamber 14 to heat the aerosol-forming substrate and create an inhalable aerosol.

[0068] Figure 1 further shows a first substrate layer 16. Disposed on the first substrate layer 16 is a heating element 18 in the form of a heating track. Electrical heater contacts 20 of the heating element 18 are also shown in Figure 1. Disposed on the first substrate layer 16 is a first adhesive layer 22 for attachment between the first substrate layer 16 and the heating element 18. Additionally, the surface area of ​​the first substrate layer 16 not covered by the heating element 18 may be attached to a second substrate layer 24 via the first adhesive layer 22.

[0069] FIG. 1 also shows a second substrate layer 24. A second adhesive layer 26 is disposed on the second substrate layer 24. The second adhesive layer 26 functions to enable attachment between the second substrate layer 24 and the temperature sensor 28. The second adhesive layer 26 further facilitates attachment between the second substrate layer 24 and the sensor contact 30 of the temperature sensor 28. Finally, the second adhesive layer 26 facilitates attachment between the second substrate layer 24 and a third substrate layer 38. The third substrate layer 38 is disposed over the temperature sensor 28, as described in more detail below with reference to FIG. 3. The third substrate layer 38 is not shown in FIG. 1. Finally, a heat shrink layer 32 is positioned over the heating assembly 10. Heating the heat shrink layer 32 facilitates secure retention of all components of the heating assembly 10.

[0070] 2 shows the layers of the heating assembly 10 in more detail. The inner layer is formed by the stainless steel tube 12. A tube adhesive layer 34 is utilized to connect the stainless steel tube 12 to the first substrate layer 16. As the next layer, the heating element 18 is positioned on the first substrate layer 16 via the first adhesive layer 22. A heater adhesive layer 36 is positioned between the heating element 18 and the second substrate layer 24. Finally, the temperature sensor 28 is positioned on the second substrate layer 24 via the second adhesive layer 26.

[0071] FIG. 2 further illustrates the preferred thicknesses of all layers.

[0072] Figure 3 shows the additional placement of a third substrate layer 38 over the temperature sensor 28 via a sensor adhesive layer 40. The third substrate layer 38 is provided with at least two openings 42 to allow the sensor contacts 30 to be contacted through the third substrate layer 38. Figure 3 also shows the preferred thicknesses of all layers.

[0073] FIG. 4 shows a different view of the heating assembly 10 from above, showing the heating assembly 10 before it is rolled into a tube.

[0074] The heating tracks of the heating element 18 are illustrated in Figure 4. Two heater contacts 20 are provided to allow for the supply of electrical energy to the heating element 18. Additionally, two sensor contacts 30 are provided to electrically contact the temperature sensor 28. Openings in the third substrate layer 38 are shown in Figure 4 to allow for contact with the temperature sensor 28 via the sensor contacts 30. Additionally, Figure 4 shows a third opening in the center of the third substrate layer 38 to improve the mechanical strength of the connection of the temperature sensor 28, as the contacts can make contact with the sensor adhesive layer 40 through this opening.

Claims

1. 1. A heating assembly for an aerosol generating device, the heating assembly comprising: a first substrate layer, the first substrate layer being an electrically insulating substrate layer; a heating element disposed on the first substrate layer; a second substrate layer, the second substrate layer being an electrically insulating substrate layer and disposed to cover the heating element and the first substrate layer; a temperature sensor disposed on the second substrate layer; a third substrate layer, the third substrate layer being an electrically insulating substrate layer at least partially covering the temperature sensor and positioned to cover the second substrate layer, the third substrate layer comprising: a first adhesive layer is provided between said first substrate layer and said heating element; a second adhesive layer is provided between the heating element and the second substrate layer; a third adhesive layer is provided between said second substrate layer and said temperature sensor; a fourth adhesive layer is provided between said temperature sensor and said third substrate layer.

2. The heating assembly of claim 1 , wherein the heating element is a resistive heater.

3. 3. The heating assembly of claim 1 or 2, wherein the heating element comprises a heating track, preferably the heating element is a heating track.

4. The heating assembly of any one of claims 1 to 3, wherein the heating element is printed onto the first substrate layer.

5. The heating assembly of any one of claims 1 to 4, wherein the heating assembly is rolled into a tube.

6. The heating assembly of any preceding claim, wherein the temperature sensor comprises two contacts.

7. The heating assembly of any preceding claim, wherein the third substrate layer includes at least two openings.

8. 8. The heating assembly of claim 7, which is dependent on claim 6, wherein the two openings are aligned such that the two contacts are not covered by the third substrate layer.

9. The heating assembly of any preceding claim, wherein a heat shrink layer is disposed around the heating assembly.

10. The heating assembly of any preceding claim, wherein one or more of the first substrate layer, the second substrate layer, and the third substrate layer comprises a polyamide film.

11. An aerosol generating device comprising a heating assembly according to any one of claims 1 to 10.

12. 12. The aerosol generating device of claim 11, wherein the aerosol generating device includes a cavity for receiving an aerosol-generating article, and the heating assembly is positioned to at least partially surround the cavity.

13. 13. The aerosol generating device of claim 12, wherein the sidewall of the cavity is formed from a stainless steel tube, and the heating assembly is mounted on the stainless steel tube.

14. 1. A method of manufacturing a heating assembly for an aerosol generating device, the method comprising: providing a first substrate layer, said first substrate layer being an electrically insulating substrate layer; disposing a heating element on the first substrate layer; disposing a second substrate layer covering the heating element and the first substrate layer, the second substrate layer being an electrically insulating substrate layer; disposing a temperature sensor on the second substrate layer; disposing a third substrate layer at least partially covering the temperature sensor and overlying the second substrate layer, the third substrate layer being an electrically insulating substrate layer, wherein the third substrate layer is an electrically insulating substrate layer; - providing a first adhesive layer between said first substrate layer and said heating element; - providing a second adhesive layer between the heating element and the second substrate layer; - providing a third adhesive layer between said second substrate layer and said temperature sensor; - providing a fourth adhesive layer between the temperature sensor and the third substrate layer.

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