Aerosol-generating device including sensing assembly having heat dissipation structure

Abstract

The present invention relates to an aerosol-generating device comprising a chamber for receiving an aerosol-forming substrate and a sensing assembly for detecting the aerosol-forming substrate in the chamber. The sensing assembly includes a multi-layer substrate including a first outer layer defining a first side of the substrate and a second outer layer defining a second side of the substrate; an emitter configured to emit electromagnetic radiation into the cavity and disposed on the first outer layer on the first portion of the substrate; a sensor configured to measure the received electromagnetic radiation of at least one wavelength and disposed on the first outer layer on the second portion of the substrate; and at least one heat dissipation structure selected from the group consisting of a metal backing layer disposed on a surface of the second outer layer of the substrate and an extended end portion of the substrate positioned adjacent to the first portion or adjacent to the second portion. The extended end portion extends at least 5 millimeters beyond the first portion or the second portion and is free of any conductive rails on a surface thereof.

Description

Technical Field

[0001] The present invention relates to an aerosol generating device. The present invention also relates to an aerosol generating system. Background Art

[0002] There are known aerosol generating devices for generating an inhalable vapor. Such devices can heat an aerosol-forming substrate to a temperature at which one or more components of the aerosol-forming substrate are volatilized without burning the aerosol-forming substrate. The aerosol-forming substrate can be provided as part of an aerosol-generating article. The aerosol-generating article can have a strip shape for inserting the aerosol-generating article into a cavity (such as a heating chamber) of the aerosol generating device. A heating assembly can be arranged in or around the heating chamber to heat the aerosol-forming substrate once the aerosol-generating article is inserted into the heating chamber of the aerosol generating device.

[0003] Aerosol generating devices generally include a number of electronic components for enabling different functions of the device. Due to heat conduction away from the hot heating chamber during use, the temperature of such electronic components can rise to an unfavorable high temperature. This can be particularly severe for electronic components that need to be located very close to the heating chamber and are not tolerant of very high temperatures. For example, an optical component can be positioned near an opening of the heating chamber to identify the insertion of the aerosol-generating article into the heating chamber. At the same time, electronic components such as optical components generally may not operate at overly high temperatures. Summary of the Invention

[0004] Accordingly, there is a desire to provide an aerosol generating device that reduces the temperature rise of electronic components during use. There is a desire to provide an aerosol generating device with improved heat dissipation.

[0005] According to an embodiment of the present invention, there is provided an aerosol generating device. The aerosol generating device can include a cavity for receiving an aerosol-forming substrate. The aerosol generating device can include a sensing assembly for detecting the aerosol-forming substrate in the cavity. The sensing assembly can include a multi-layer substrate. The multi-layer substrate can include a first outer layer defining a first side of the substrate. The multi-layer substrate can include a second outer layer defining a second side of the substrate. The sensing assembly can include a transmitter configured to emit electromagnetic radiation into the cavity. The transmitter can be disposed on the first outer layer on a first portion of the substrate. The sensing assembly can include a sensor configured to measure the received electromagnetic radiation at at least one wavelength. The sensor can be disposed on the first outer layer on a second portion of the substrate. The sensing assembly can include at least one heat dissipation structure. The heat dissipation structure can be selected from a metal backing layer disposed on a surface of the second outer layer of the substrate, and an extended end portion of the substrate located adjacent to the first portion or adjacent to the second portion. The extended end portion can extend beyond the first portion or the second portion by at least 5 millimeters. The extended end portion can have no conductive tracks on its surface.

[0006] According to an embodiment of the present invention, an aerosol generating device is provided. The aerosol generating device includes a chamber for receiving an aerosol-forming substrate and a sensing assembly for detecting the aerosol-forming substrate in the chamber. The sensing assembly includes a multilayer substrate. The multilayer substrate includes a first outer layer defining a first side of the substrate and a second outer layer defining a second side of the substrate. The sensing assembly includes a transmitter configured to emit electromagnetic radiation into the chamber. The transmitter is disposed on the first outer layer on a first portion of the substrate. The sensing assembly includes a sensor configured to measure the received electromagnetic radiation at at least one wavelength. The sensor is disposed on the first outer layer on a second portion of the substrate. The sensing assembly includes at least one heat dissipation structure. The at least one heat dissipation structure is selected from one or both of a metal backing layer and an extended end portion of the substrate. The metal backing layer is disposed on a surface of the second outer layer of the substrate. The extended end portion is positioned adjacent to the first portion or adjacent to the second portion. The extended end portion extends beyond the first portion or the second portion by at least 5 millimeters. The outer surface of the extended end portion of the substrate has no conductive tracks.

[0007] The sensing assembly may include a metal backing layer. The sensing assembly may include an extended end portion of the substrate. The sensing assembly may include both a metal backing layer and an extended end portion of the substrate.

[0008] By means of the sensing assembly including at least one heat dissipation structure, an aerosol generating device with reduced temperature rise of electronic components during use can be provided. By means of the sensing assembly including at least one heat dissipation structure, an aerosol generating device with improved heat dissipation can be provided.

[0009] The aerosol generating device including the sensing assembly can advantageously be capable of detecting the presence and type of the aerosol-forming substrate at least partially received in the chamber based on the measurement of the received electromagnetic radiation at at least one wavelength obtained by the sensor. The aerosol-forming substrate may be included in an aerosol generating article at least partially received in the chamber. In use, the transmitter can advantageously emit electromagnetic radiation into the chamber in which at least partially the aerosol-forming substrate is received. The electromagnetic radiation incident on the aerosol-forming substrate or the aerosol generating article may undergo one of the following: absorption, reflection, or transmission. The amount of absorption, reflection, or transmission of the electromagnetic radiation at different wavelengths may depend on the chemical structure of the aerosol-forming substrate or the article. Therefore, the chemical structure of the aerosol-forming substrate or the article may affect the electromagnetic radiation received by the sensor from the chamber. Different aerosol-forming substrates or articles may have different chemical structures and thus may affect the electromagnetic radiation differently. Therefore, measuring the received electromagnetic radiation can advantageously be used to determine the presence and type of the aerosol-forming substrate received in the chamber.

[0010] Preferably, the sensor is configured to measure the intensity of electromagnetic radiation at at least one wavelength. The measurement may include comparing the intensity of electromagnetic radiation at at least one wavelength with a threshold.

[0011] By means of a sensing assembly including at least one heat dissipation structure of the present invention, the temperature rise of the sensing assembly during use can be reduced by virtue of the heat dissipation function of the at least one heat dissipation structure.

[0012] The chamber of the aerosol generating device may include an opening at a first end through which an aerosol-forming substrate can be received. The chamber may be configured to receive the aerosol-forming substrate along a longitudinal axis of the chamber. The longitudinal axis of the chamber may be parallel to the longitudinal axis of the aerosol generating device.

[0013] The emitter and the sensor may be positioned at substantially the same height relative to the longitudinal axis of the chamber. In other words, the emitter and the sensor may be positioned in a plane substantially perpendicular to the longitudinal axis of the chamber. The emitter and the sensor may be positioned such that an electromagnetic radiation beam travels from the emitter to the sensor in a direction substantially perpendicular to the longitudinal axis of the chamber.

[0014] The chamber may include a second end opposite the first end. The second end may include a base of the chamber.

[0015] The emitter and the sensor may be positioned to emit electromagnetic radiation to and receive electromagnetic radiation from the chamber at a region between the first end and the second end of the chamber. The emitter may be positioned outside the chamber. The sensor may be positioned outside the chamber.

[0016] The emitter and the sensor may be positioned distally of the second end of the chamber along the longitudinal axis of the chamber. The emitter and the sensor may be positioned to emit electromagnetic radiation to and receive electromagnetic radiation from the second end of the chamber, respectively.

[0017] The sensing assembly may include a shielding plate configured to block electromagnetic radiation. The shielding plate may be positioned outside the chamber. The shielding plate may be positioned outside the chamber such that the sensor is disposed between the chamber and at least a portion of the shielding plate. The shielding plate may be positioned outside the chamber such that the sensor is disposed between the longitudinal central axis of the chamber and at least a portion of the shielding plate. The sensor may be positioned between a first portion of the shielding plate and the chamber, and the emitter may be positioned between a second portion of the shielding plate and the chamber.

[0018] The shielding plate may be positioned outside the chamber such that at least a portion of the substrate is disposed between the chamber and at least a portion of the shielding plate. The shielding plate may be positioned outside the chamber such that at least a portion of the substrate is disposed between the longitudinal central axis of the chamber and at least a portion of the shielding plate.

[0019] The first and second portions of the substrate can be planar. The planar first and second portions of the substrate can be non-coplanar. The angle between the normal of the planar first portion of the substrate and the normal of the planar second portion can be between 60 degrees and 100 degrees, preferably between 70 degrees and 90 degrees, and more preferably can be about 80 degrees.

[0020] The substrate includes a first side to which the emitter and the sensor are attached. The substrate can include a second side opposite the first side to which a shielding plate is attached. This can advantageously be a simple arrangement that is easy to manufacture. The substrate can include one or more printed circuit boards (PCBs). The substrate can be a printed circuit board (PCB). The substrate can include more than one PCB. The substrate can include one or more flexible PCBs or consist of one or more flexible PCBs.

[0021] The substrate can include a flexible portion. The flexible portion can be configured such that the emitter is movable relative to the sensor by bending the flexible portion. The angle between the emitter and the sensor can preferably be between 20 and 120 degrees, preferably between 60 and 100 degrees, and even more preferably between 70 and 90 degrees. Most preferably, the angle between the sensor and the emitter can be about 80 degrees. A substrate including a flexible portion can advantageously allow the angle between the emitter and the sensor to be controlled in a simple manner during the manufacturing process. Using a substrate including a flexible portion can advantageously eliminate the need to pre-mold the substrate into a desired shape. The angle between the emitter and the sensor can be modified during or after the manufacture of the aerosol forming device. When referring herein to the angle between the emitter and the sensor, this angle is defined between the central optical axis of the emitter and the central optical axis of the sensor. This can be the same as the angle defined between the surface of the aerosol forming substrate or article at least partially received in the cavity and the emitter and the sensor. The angle between the normal of the plane of the first portion and the normal of the plane of the second portion can be substantially the same as the angle between the sensor and the emitter.

[0022] The substrate can be bent such that the emitter and the sensor are adjacent to different portions of the cavity and such that the angle between the central optical axes of the emitter and the sensor is between 20 degrees and 120 degrees, preferably between 60 degrees and 100 degrees, and even more preferably between 70 degrees and 90 degrees. Most preferably, the angle between the sensor and the emitter can be about 80 degrees.

[0023] The substrate can include a third portion between the first and second portions. At least the third portion can be flexible such that the first portion is movable relative to the second portion. As described above, this can allow the angle between the emitter and the sensor to be controlled.

[0024] Preferably, a metal backing layer is not provided on the surface of the second outer layer of the third portion of the substrate.

[0025] Preferably, the first part of the substrate can be rigid. The second part of the substrate can be rigid. In this way, the flexible third part acts as a hinge between the rigid first part and the second part.

[0026] Preferably, the third part of the substrate can be impermeable to electromagnetic radiation of each wavelength emitted by the emitter. This can advantageously ensure that the electromagnetic radiation emitted by the emitter is not directly received by the sensor before being reflected or absorbed by the aerosol-forming matrix received in the cavity and emitted.

[0027] The substrate can include one or more PCBs. The substrate can be composed of one or more flexible PCBs. At least the third part of the substrate can include a flexible PCB or be composed of a flexible PCB.

[0028] Preferably, the first part and the second part of the substrate can include rigid PCBs, and the third part can include a flexible PCB.

[0029] The shielding plate can include a planar first part and a planar second part. The planar first part and the planar second part of the shielding plate can be non-coplanar. The first part of the shielding plate can be coplanar with the first part of the substrate. The second part of the shielding plate can be coplanar with the second part of the substrate.

[0030] The sensor can be positioned between the first part of the shielding plate and the cavity. The emitter can be positioned between the second part of the shielding plate and the cavity.

[0031] A particularly preferred combination can be the combination of the substrate including a flexible part as described above and the shielding plate as described above when the shielding plate includes a first planar part and a second planar part, and the second part is planar in a plane different from the first part. This is because the shielding plate can advantageously hold the substrate such that the flexible part is bent at a desired angle.

[0032] Preferably, the shielding plate can be attached to the second side of the substrate opposite to the first side. The shielding plate can be rigid.

[0033] The first part of the shielding plate can be attached to the first part of the substrate. The second part of the shielding plate can be attached to the second part of the substrate.

[0034] This arrangement can allow for a simple manufacturing process. Advantageously, the act of attaching the shielding plate to the substrate can hold the substrate at a desired angle.

[0035] The shielding plate may include at least one fixture. The shielding plate may include a first fixture at a first end and a second fixture at a second end. The first end may be at an end of the shielding plate opposite to the second end. One or more fixtures may be configured to connect the fixture to the second side of the substrate. One or more fixtures can advantageously provide a simple and low-cost means of attaching the shielding plate to the substrate. Attaching the shielding plate to the substrate in this way can advantageously ensure simple and low-cost manufacturing of the sensing assembly.

[0036] The shielding plate may be connected to a ground contact of the aerosol generating device. The ground contact may be on the substrate. If the substrate includes a PCB, the ground contact may be on the PCB. At least one fixture of the shielding plate may be in contact with the ground contact. Connecting the shielding plate to the ground contact allows the shielding plate to provide good shielding.

[0037] The shielding plate may be integrally formed. This may include at least one fixture. The shielding plate may be a single-piece. This may include at least one fixture.

[0038] The substrate may include an intermediate layer disposed between a first outer layer and a second outer layer. The substrate may include an intermediate layer disposed between a first outer layer and a second outer layer, and the first outer layer and the second outer layer of the substrate may be printed circuit boards.

[0039] The intermediate layer may include a metal or an alloy. The intermediate layer may be a metal layer. The intermediate layer may include copper. The intermediate layer may be a copper layer.

[0040] An extended end portion of the substrate may include a metal layer or an alloy layer. The metal layer or the alloy layer may be an intermediate layer disposed between the first outer layer and the second outer layer. The metal layer or the alloy layer may include copper. The extended end portion of the substrate may include a copper layer. The copper layer may be an intermediate layer disposed between the first outer layer and the second outer layer.

[0041] The extended end portion of the substrate is positioned adjacent to a first portion or adjacent to a second portion. In the case where the extended end portion is positioned adjacent to the first portion, the first portion is located between the extended end portion and the second portion. In the case where the extended end portion is positioned adjacent to the second portion, the second portion is located between the extended end portion and the first portion.

[0042] In the case where the extended end portion of the substrate is positioned adjacent to the first portion of the substrate, the extended end portion of the substrate may extend beyond the first portion by at least 10 millimeters, preferably at least 12 millimeters, more preferably at least 14 millimeters, more preferably between 10 millimeters and 21 millimeters, more preferably between 14 millimeters and 17 millimeters.

[0043] In the case where the extended end portion of the substrate is positioned adjacent to the second portion of the substrate, the extended end portion of the substrate can extend beyond the second portion by a distance of at least 10 millimeters, preferably at least 12 millimeters, more preferably at least 14 millimeters, more preferably between 10 millimeters and 21 millimeters, and more preferably between 14 millimeters and 17 millimeters.

[0044] The sensing assembly can include both the extended end portion of the substrate and the metal backing layer, and the surface of the second outer layer of the substrate can be free of the metal backing layer in the region of the extended end portion.

[0045] The metal backing layer can be a steel layer. The metal backing layer can be a stainless steel layer. The steel can be steel according to Japanese steel standard JIS SUS304.

[0046] The metal backing layer can have a thickness between 0.1 millimeter and 0.5 millimeter, preferably between 0.2 millimeter and 0.4 millimeter, more preferably between 0.25 millimeter and 0.35 millimeter, and more preferably about 0.3 millimeter.

[0047] The metal backing layer can include one or more separate metal plates. The metal backing layer can include a first metal plate and a second metal plate. The first metal plate can be disposed on the first portion of the second outer layer of the substrate opposite the first portion of the first outer layer of the substrate. The second metal plate can be disposed on the second portion of the second outer layer of the substrate opposite the second portion of the first outer layer of the substrate. The first metal plate can be disposed on the first portion of the second outer layer of the substrate opposite the emitter. The second metal plate can be disposed on the second portion of the second outer layer of the substrate opposite the sensor.

[0048] The first metal plate can have a width between 0.2 millimeter and 0.6 millimeter, preferably between 0.35 millimeter and 0.45 millimeter, and more preferably about 0.4 millimeter. The first metal plate can have a length between 0.7 millimeter and 1.3 millimeter, preferably between 0.95 millimeter and 1.05 millimeter, and more preferably about 1.0 millimeter. The first metal plate can have a thickness between 0.1 millimeter and 0.5 millimeter, preferably between 0.2 millimeter and 0.4 millimeter, more preferably between 0.25 millimeter and 0.35 millimeter, and more preferably about 0.3 millimeter.

[0049] The first metal plate can have a width between 0.2 millimeter and 0.6 millimeter, preferably between 0.35 millimeter and 0.45 millimeter, and more preferably about 0.4 millimeter. The first metal plate can have a length between 0.7 millimeter and 1.3 millimeter, preferably between 0.95 millimeter and 1.05 millimeter, and more preferably about 1.0 millimeter. The second metal plate can have a thickness between 0.1 millimeter and 0.5 millimeter, preferably between 0.2 millimeter and 0.4 millimeter, more preferably between 0.25 millimeter and 0.35 millimeter, and more preferably about 0.3 millimeter.

[0050] The first metal plate and the second metal plate may have the same shape and size. Preferably, each of the first metal plate and the second metal plate has a width of about 0.4 mm, a length of about 1.0 mm, and a thickness of about 0.3 mm.

[0051] The sensing assembly may include an aerogel layer or an aerogel sheet. The aerogel layer or the aerogel sheet may be disposed between at least a portion of the substrate and the cavity. The sensing assembly may include an aerogel layer or an aerogel sheet. The aerogel layer or the aerogel sheet may be disposed between at least a portion of the substrate and the longitudinal central axis of the cavity. The aerogel layer or the aerogel sheet may have a thickness between 0.1 mm and 0.3 mm, preferably about 0.2 mm. The aerogel layer or the aerogel sheet may act as a thermal barrier. The aerogel layer or the aerogel sheet may help thermally insulate the substrate from the heater assembly. When at least a portion of the cavity is heated during use of the aerosol generating device, the aerogel layer or the aerogel sheet may help thermally insulate the substrate from the cavity.

[0052] The cavity may be defined by a housing of the aerosol generating device. The housing of the aerosol generating device that defines the cavity may include a first portion of the housing that defines the cavity. The first portion of the housing that defines the cavity may be penetrable to at least one wavelength of electromagnetic radiation emitted by the emitter. The first portion of the housing may preferably be penetrable to all wavelengths of electromagnetic radiation emitted by the emitter. The emitter may be configured to emit electromagnetic radiation into the cavity through the penetrable portion.

[0053] The first portion of the housing may separate the emitter from the cavity. Thus, the first portion of the housing may protect the emitter from debris and dirt that may accumulate in the cavity. In particular, the emitter may be protected from residues of the aerosol-forming substrate that may accumulate during use of the aerosol generating device. The first portion may also advantageously be easy to clean so that the device can be simply maintained.

[0054] An air flow path may be defined through the aerosol generating device from an air inlet to an air outlet. The air flow path may pass through the cavity. The emitter may be separated from the air flowing through the air flow path by the penetrable first portion of the housing. The air may carry debris or dirt. Thus, the first portion may protect the emitter from the air passing through the air flow path.

[0055] The size and position of the first portion of the housing may be set to correspond to the viewing angle of the emitter. This may advantageously ensure that substantially all of the electromagnetic radiation emitted by the emitter during use is transmitted into the cavity.

[0056] The housing of an aerosol-generating device defining a cavity may include a second part of the housing defining the cavity. The second part of the housing defining the cavity may be penetrable to electromagnetic radiation of at least one wavelength received by a sensor. The sensor may be configured to receive electromagnetic radiation from the cavity through the second penetrable part.

[0057] The second part of the housing may have corresponding features and advantages as described with respect to the first part, only with respect to the sensor and not with respect to the emitter.

[0058] The arrangement of the first and second parts of the housing may advantageously increase the lifespan of the sensing assembly. The first and second parts of the housing may prevent the sensing assembly from deteriorating over time, for example due to being covered with dirt, debris, and matrix residues. In a deteriorated sensing assembly, the amount of electromagnetic radiation entering the cavity from the emitter or received by the sensor from the cavity may be reduced, which would reduce the accuracy and sensitivity of the sensing assembly.

[0059] The cavity of the aerosol-generating device may have an open end into which an aerosol-generating article is inserted. The open end may be the proximal end. The cavity may have a closed end opposite the open end. The closed end may be the base of the cavity. The closed end may be closed except for providing air holes arranged in the base. The base of the cavity may be flat. The base of the cavity may be circular. The base of the cavity may be arranged upstream of the cavity. The open end may be arranged downstream of the cavity. The cavity may have an elongate extension. The cavity may have a longitudinal central axis. The longitudinal direction may be the direction extending along the longitudinal central axis between the open end and the closed end. The longitudinal central axis of the cavity may be parallel to the longitudinal axis of the aerosol-generating device.

[0060] At least a portion of the cavity may be configured as a heating chamber. The distal part of the cavity may be configured as a heating chamber. The cavity may have a cylindrical shape. The cavity may have a hollow cylindrical shape. The shape of the cavity may correspond to the shape of the aerosol-generating article to be received in the cavity. The cavity may have a circular cross-section. The cavity may have an oval or rectangular cross-section. The cavity may have an inner diameter corresponding to the outer diameter of the aerosol-generating article.

[0061] An air flow channel may pass through the cavity. Ambient air may be drawn into the aerosol-generating device through the air flow channel, into the cavity, and towards the user. Downstream of the cavity, a mouthpiece may be arranged, or the user may draw directly on the aerosol-generating article. The air flow channel may extend through the mouthpiece.

[0062] The aerosol-generating device may be configured such that during operation of the device, the temperature of the sensing assembly does not exceed 120 degrees Celsius, preferably does not exceed 110 degrees Celsius, more preferably does not exceed 100 degrees Celsius, more preferably does not exceed 95 degrees Celsius, more preferably does not exceed 90 degrees Celsius, more preferably does not exceed 87 degrees Celsius.

[0063] An aerosol generating device may include at least one lens configured to focus electromagnetic radiation received from a chamber onto a sensor. The lens may include an absorbing material configured to substantially block electromagnetic radiation having wavelengths outside a wavelength range. The absorbing material may be configured to substantially block electromagnetic radiation having wavelengths less than 200 nanometers and greater than 30,000 nanometers. The one or more lenses may advantageously increase the amount of electromagnetic radiation received by the sensor. This may advantageously increase the signal-to-noise ratio of the sensing assembly and thus improve the accuracy of the sensing assembly in detecting the presence and type of an aerosol-forming substrate at least partially received in the chamber.

[0064] The sensing assembly may include amplification electronics directly connected to the sensor.

[0065] The aerosol generating device may include a controller. The controller may be configured to receive a signal from the sensor. The controller may be configured to determine a material property of an aerosol-forming substrate at least partially received in the chamber based on a measured intensity of electromagnetic radiation received at the sensor. The controller may be configured to determine a material property of an aerosol generating article including the aerosol-forming substrate based on a measured intensity of electromagnetic radiation received at the sensor.

[0066] Preferably, the controller may be configured to perform a spectral analysis of the measured intensity of the electromagnetic radiation to determine a material property of the aerosol-forming substrate or an aerosol generating article including the aerosol-forming substrate. Based on the determined material property, the controller may be configured to determine the type of the aerosol-forming substrate at least partially received in the chamber. The controller being configured to determine a material property of the aerosol-forming substrate may advantageously mean that the type of the aerosol-forming substrate can be determined directly based on the inherent material property of the aerosol-forming substrate. There is no need for the aerosol-forming substrate or an aerosol generating article including the aerosol-forming substrate to include a printed bar code, marker, or other marking of the substrate type.

[0067] The material property determined by the controller may be the humidity or water content of the aerosol-forming substrate.

[0068] The controller may include a memory. Data associating known measurements of electromagnetic radiation at specific wavelengths with the chemical structure or type of an aerosol-forming substrate may be stored in the memory of the controller. The controller may be configured to determine the type of the aerosol-forming substrate received in the chamber by comparing one or more electromagnetic radiation measurements obtained by the sensor at one or more wavelengths with the known measurements stored in the memory. The aerosol generating device may include a heating assembly for heating the aerosol-forming substrate. The heating assembly may be controlled by the controller. The controller may be configured to control the heating assembly according to a heating curve selected based on the determined type of the aerosol-forming substrate.

[0069] The controller can be configured to repeatedly determine, during use of the aerosol-generating device, a value related to the water content of the aerosol-forming substrate received in the chamber. Preferably, the controller can be configured to modify the heating curve based on the determined change in the water content of the aerosol-forming substrate. The determined change in water content can be relative to the expected water content of the determined type of aerosol-forming substrate. Alternatively or additionally, the determined change in water content can be the change in the determined water content over time. For example, the determined change in water content can be the change in the water content determined during or between puffs.

[0070] The emitter can be configured to emit electromagnetic radiation having a wavelength between 1100 nanometers and 1500 nanometers. Preferably, the emitter can be configured to emit electromagnetic radiation having a wavelength between 1350 nanometers and 1400 nanometers.

[0071] The sensor can be configured to receive electromagnetic radiation having a wavelength between 1100 nanometers and 1500 nanometers. Preferably, the sensor can be configured to receive electromagnetic radiation having a wavelength between 1350 nanometers and 1400 nanometers.

[0072] Water is particularly effective at absorbing electromagnetic radiation having a wavelength between 1100 nanometers and 1500 nanometers, particularly between 1350 nanometers and 1400 nanometers. Thus, when the relevant material property of the aerosol-forming substrate is humidity or water content, it may be advantageous for the emitter and sensor to emit and receive electromagnetic radiation of this wavelength.

[0073] The emitter can include at least one LED that emits electromagnetic radiation.

[0074] Preferably, the emitter can be configured to emit electromagnetic radiation of multiple wavelengths. The emitter can include a plurality of LEDs, each of the plurality of LEDs being configured to emit electromagnetic radiation of a different wavelength.

[0075] The sensor can include a photodiode.

[0076] The sensor can be configured to receive electromagnetic radiation of multiple wavelengths. In particular, the sensor can be configured to measure the received electromagnetic radiation of multiple wavelengths.

[0077] In other words, the sensing assembly can be configured to perform a spectral inspection on the aerosol-forming substrate received in the chamber or on the aerosol-generating article including the substrate received in the chamber. The device can include a controller that performs spectral analysis on the measured electromagnetic radiation. Based on the spectral analysis, the controller can be configured to determine whether an aerosol-forming substrate is present in the chamber. The controller can be configured to determine the type of aerosol-forming substrate in the chamber.

[0078] In this document, determining the presence and type of an aerosol - forming substrate is used interchangeably with determining the presence and type of an aerosol - generating article comprising the aerosol - forming substrate. In either case, the aerosol - generating device can advantageously be configured to determine the presence and type of the aerosol - forming substrate or article based on the chemical composition of the aerosol - forming substrate or article.

[0079] In one example, electromagnetic radiation emitted by a transmitter can be incident on the aerosol - forming substrate, in which case the presence or type of the aerosol - forming substrate can be determined.

[0080] Alternatively, the aerosol - forming substrate can be included in an aerosol - generating article. In this case, the electromagnetic radiation received by a sensor can be affected by the chemical structure of the aerosol - generating article, such as the wrapper or housing of the article. Different aerosol - generating articles can include different chemical structures, such as different wrappers or housings. This can allow for the identification of different aerosol - generating articles.

[0081] “Different aerosol - generating articles” can refer to aerosol - generating articles that include different aerosol - forming substrates.

[0082] Furthermore, a portion of the electromagnetic radiation can pass through the aerosol - generating device to reach the aerosol - forming substrate, such that the electromagnetic radiation received by the sensor can be affected by the chemical structures of both the aerosol - generating article and the substrate.

[0083] The aerosol - forming substrate can be a solid aerosol - forming substrate. Alternatively, the aerosol - forming substrate can include both solid and liquid components. The aerosol - forming substrate can include a tobacco - containing material, which contains volatile tobacco flavor compounds that are released from the substrate upon heating. Alternatively, the aerosol - forming substrate can include a non - tobacco material. The aerosol - forming substrate can also include an aerosol - forming agent that aids in the formation of a dense and stable aerosol. Examples of suitable aerosol - forming agents are glycerol and propylene glycol.

[0084] If the aerosol - forming substrate is a solid aerosol - forming substrate, the solid aerosol - forming substrate can include, for example, one or more of the following: powders, granules, pellets, fragments, strips, ribbons, or sheets that contain one or more of herbaceous leaves, tobacco leaves, tobacco ribs, reconstituted tobacco, homogenized tobacco, extruded tobacco, cast - leaf tobacco, and expanded tobacco. The solid aerosol - forming substrate can be in a loose form or can be provided in a suitable container or cartridge. Optionally, the solid aerosol - forming substrate can contain additional tobacco or non - tobacco volatile flavor compounds that are released when the substrate is heated. The solid aerosol - forming substrate can also contain capsules, which, for example, include additional tobacco or non - tobacco volatile flavor compounds, and such capsules can melt during heating of the solid aerosol - forming substrate.

[0085] As used herein, homogenized tobacco refers to a material formed by agglomerating particulate tobacco. The homogenized tobacco can be in the form of a sheet. The homogenized tobacco material can have an aerosol former present in an amount greater than 5% by dry weight. Alternatively, the homogenized tobacco material can have an aerosol former present in an amount between 5 wt% and 30 wt% by dry weight. The sheet of homogenized tobacco material can be formed by agglomerating particulate tobacco obtained by grinding or otherwise combining one or both of tobacco leaves and tobacco stems. Alternatively or additionally, the sheet of homogenized tobacco material can include one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed during, for example, the handling, processing, and transportation of tobacco. The sheet of homogenized tobacco material can include one or more intrinsic binders that are endogenous to the tobacco, one or more non-intrinsic binders that are exogenous to the tobacco, or a combination thereof to aid in the agglomeration of the particulate tobacco; alternatively or additionally, the sheet of homogenized tobacco material can include other additives including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous solvents, and non-aqueous solvents, and combinations thereof.

[0086] Optionally, the solid aerosol-forming matrix can be disposed on or embedded in a heat-stable carrier. The carrier can take the form of a powder, granule, pellet, fragment, strip, ribbon, or sheet. Alternatively, the carrier can be a tubular carrier having a thin layer of the solid matrix deposited on its inner surface, its outer surface, or both its inner and outer surfaces. Such tubular carriers can be formed from, for example, paper or paper-like materials, non-woven carbon fiber mats, low mass openmesh metallic screens, or perforated metal foils, or any other heat-stable polymeric matrix.

[0087] In a particularly preferred embodiment, the aerosol-forming substrate comprises an aggregated crimped sheet of homogenized tobacco material. As used herein, the term "crimped sheet" means a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, when the aerosol-generating article has been assembled, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article. This advantageously facilitates the aggregation of the crimped sheets of homogenized tobacco material to form the aerosol-forming substrate. However, it should be understood that the crimped sheets of homogenized tobacco material for inclusion in an aerosol-generating article may alternatively or additionally have a plurality of substantially parallel ridges or corrugations that are disposed at an acute or obtuse angle to the longitudinal axis of the aerosol-generating article when the aerosol-generating article has been assembled. In certain embodiments, the aerosol-forming substrate may comprise an aggregated sheet of homogenized tobacco material that is substantially uniformly textured over substantially its entire surface. For example, the aerosol-forming substrate may comprise an aggregated crimped sheet of homogenized tobacco material that includes a plurality of substantially parallel ridges or corrugations that are spaced apart substantially evenly across the width of the sheet.

[0088] The solid aerosol-forming substrate may be deposited on the surface of the carrier in the form of, for example, a sheet, a foam, a gel or a slurry. The solid aerosol-forming substrate may be deposited over the entire surface of the carrier or, alternatively, may be deposited in a pattern so as to provide non-uniform flavor delivery during use.

[0089] The aerosol-generating device may include a heater assembly. The heater assembly may be configured to heat the aerosol-forming substrate received in the chamber during use. A controller may be configured to control the heater assembly. The control of the heater assembly may be based on the type of aerosol-forming substrate determined by the controller. Preferably, the controller may be configured to control the heater assembly according to a heating profile. The heating profile may be selected or modified according to the type of aerosol-forming substrate received at least partially in the chamber.

[0090] The heater assembly may include a heating element. In use, electrical power may be supplied to the heating element, causing the heating element to become hot. The heat may then be transferred to the received aerosol-forming substrate, for example, by conduction through the device housing forming the chamber.

[0091] The heating element may be a resistive heating element. The heating element may include a resistive material. Suitable resistive materials include, but are not limited to: semiconductors such as doped ceramics, electro-“conductive” ceramics (e.g., molybdenum disilicide), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped or undoped ceramics.

[0092] In another example, the heater assembly may include one or more inductor coils, and the heating element may include one or more susceptor elements.

[0093] The one or more susceptor elements may be configured to be heated by an alternating magnetic field generated by the one or more inductor coils. In use, the power supplied to the inductor coils (e.g., by the power source of the device) may cause the inductor coils to induce eddy currents in the susceptor elements. These eddy currents in turn cause the susceptor elements to generate heat. The power is supplied to the inductor coils as an alternating magnetic field. The alternating current may have any suitable frequency. The alternating current may preferably be a high-frequency alternating current. The alternating current may have a frequency between 100 kilohertz (kHz) and 30 megahertz (MHz). When the aerosol-forming substrate is received in the chamber, the heat generated by the susceptor elements may heat the aerosol-forming substrate to a temperature sufficient to release the aerosol from the substrate. The susceptor elements may be formed of a material having the ability to absorb electromagnetic energy and convert it into heat. By way of example and not limitation, the susceptor elements may be formed of a ferromagnetic material such as steel.

[0094] The aerosol generating device may include a power source configured to supply current to a resistive heating element.

[0095] The heating element may include a substrate layer of a flexible material. The substrate layer may include a heat-stable polymer, preferably polyimide.

[0096] The heating element may be disposed on the substrate layer. The heating element may include electrical connections configured to connect to a controller of the aerosol generating device. The heating element may include heating tracks disposed on the substrate layer. The heating tracks may include a thermally conductive material, preferably a metal such as stainless steel. The heating tracks may be electrically connected to the electrical connections.

[0097] The heating element may take other forms. For example, coating techniques such as plasma vapor deposition may be used to form one or more metal grids, flexible printed circuit boards, moulded interconnect devices (MIDs), ceramic heaters, flexible carbon fiber heaters on a substrate of a suitable shape.

[0098] As used herein, in the context of the penetrable portion or otherwise, the penetrability of electromagnetic radiation of certain wavelengths means that at least 90%, preferably at least 95%, and even more preferably at least 99% of the electromagnetic radiation of said wavelengths can pass through the first part or the second part without being absorbed.

[0099] The present invention also relates to a sensing assembly for an aerosol-generating device configured to generate an aerosol from an aerosol-forming substrate. The aerosol-generating device may include a chamber for receiving the aerosol-forming substrate. The sensing assembly may include a multilayer substrate. The multilayer substrate may include a first outer layer defining a first side of the substrate. The multilayer substrate may include a second outer layer defining a second side of the substrate. The sensing assembly may include a transmitter configured to emit electromagnetic radiation into the chamber. The transmitter may be disposed on the first outer layer on a first portion of the substrate. The sensing assembly may include a sensor configured to measure the received electromagnetic radiation at at least one wavelength. The sensor may be disposed on the first outer layer on a second portion of the substrate. The sensing assembly may include at least one heat dissipation structure. The heat dissipation structure may be selected from a metal backing layer disposed on a surface of the second outer layer of the substrate, and an extended end portion of the substrate located adjacent to the first portion or adjacent to the second portion. The extended end portion may extend beyond the first portion or the second portion by at least 5 millimeters. The extended end portion may have no conductive tracks on its surface.

[0100] The sensing assembly may include any feature described in any aspect of the previous aspects of the present disclosure.

[0101] The present invention also relates to an aerosol-generating system comprising an aerosol-generating device as described herein and an aerosol-generating article comprising an aerosol-forming substrate.

[0102] As used herein, the terms "proximal", "distal", "upstream" and "downstream" are used to describe the relative positions of components or parts of an aerosol-generating device relative to the direction in which a user draws on the aerosol-generating device during use.

[0103] As used herein, an "aerosol-generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of an aerosol-generating article, such as part of a smoking article. The aerosol-generating device may be a smoking device that interacts with the aerosol-forming substrate of the aerosol-generating article to generate an aerosol that can be directly inhaled into a user's lungs through the user's mouth. The aerosol-generating device may be a holder. The device may be an electrically heated smoking device. The aerosol-generating device may include a housing, a circuit, a power source, a heating chamber, and a heating element.

[0104] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of releasing volatile compounds that can form an aerosol. For example, the aerosol-generating article may be a smoking article that generates an aerosol that can be directly inhaled into a user's lungs through the user's mouth. The aerosol-generating article may be disposable.

[0105] As used herein, the term "aerosol - forming substrate" refers to a substrate capable of releasing one or more volatile compounds that can form an aerosol. Such volatile compounds can be released by heating the aerosol - forming substrate. The aerosol - forming substrate can suitably be part of an aerosol - generating article or a smoking article.

[0106] The following provides a non - exhaustive list of non - limiting examples. Any one or more features of these examples can be combined with any one or more features of another example, embodiment, or aspect described herein.

[0107] Example E1: An aerosol - generating device, the aerosol - generating device comprising a chamber for receiving an aerosol - forming substrate and a sensing assembly for detecting the aerosol - forming substrate in the chamber; the sensing assembly comprises

[0108] a multi - layer substrate comprising a first outer layer defining a first side of the substrate and a second outer layer defining a second side of the substrate;

[0109] a transmitter configured to emit electromagnetic radiation into the chamber and disposed on the first outer layer on a first portion of the substrate;

[0110] a sensor configured to measure the received electromagnetic radiation at at least one wavelength and disposed on the first outer layer on a second portion of the substrate; and

[0111] at least one heat - dissipating structure selected from:

[0112] - a metal backing layer disposed on a surface of the second outer layer of the substrate, and

[0113] - an extended end portion of the substrate positioned adjacent to the first portion or adjacent to the second portion, the extended end portion extending at least 5 millimeters beyond the first portion or the second portion and having no conductive tracks on its surface.

[0114] Example E2: The aerosol - generating device according to Example E1, wherein the substrate comprises one or more printed circuit boards, preferably one or more flexible printed circuit boards.

[0115] Example E3: The aerosol - generating device according to Example E1 or Example E2, wherein the substrate comprises an intermediate layer disposed between the first outer layer and the second outer layer, preferably wherein the first outer layer and the second outer layer of the substrate are printed circuit boards.

[0116] Example E4: The aerosol - generating device according to Example E3, wherein the intermediate layer is a metal layer, preferably wherein the intermediate layer comprises copper, more preferably wherein the intermediate layer is a copper layer.

[0117] Example E5: An aerosol-generating device according to any one of the preceding examples, comprising an extended end portion of the substrate, wherein the extended end portion comprises a copper layer, preferably wherein the copper layer is an intermediate layer disposed between the first outer layer and the second outer layer.

[0118] Example E6: An aerosol-generating device according to any one of the preceding examples, comprising an extended end portion of the substrate positioned adjacent to the first portion or adjacent to the second portion, wherein the extended end portion extends beyond the first portion or the second portion by at least 10 mm, preferably at least 12 mm, more preferably at least 14 mm, and more preferably a distance between 14 mm and 17 mm.

[0119] Example E7: An aerosol-generating device according to any one of the preceding examples, comprising both the extended end portion of the substrate and the metal backsheet layer, and wherein the metal backsheet layer is not disposed on the surface of the second outer layer of the substrate in the region of the extended end portion.

[0120] Example E8: An aerosol-generating device according to any one of the preceding examples, comprising the metal backsheet layer, wherein the metal backsheet layer is a steel layer, preferably a stainless-steel layer, and more preferably wherein the steel is JIS SUS304.

[0121] Example E9: An aerosol-generating device according to any one of the preceding examples, comprising the metal backsheet layer, wherein the metal backsheet layer has a thickness between 0.1 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm, and more preferably between 0.25 mm and 0.35 mm.

[0122] Example E10: An aerosol-generating device according to any one of the preceding examples, comprising the metal backsheet layer, wherein the metal backsheet layer comprises a first separate metal plate and a second separate metal plate, preferably wherein the first metal plate is disposed on a first portion of the second outer layer of the substrate opposite a first portion of the first outer layer of the substrate, and the second metal plate is disposed on a second portion of the second outer layer of the substrate opposite a second portion of the first outer layer of the substrate.

[0123] Example E11: The aerosol-generating device according to Example E10, wherein each of the first metal plate and the second metal plate has a width between 0.2 mm and 0.6 mm, preferably between 0.35 mm and 0.45 mm, and a length between 0.7 mm and 1.3 mm, preferably between 0.95 mm and 1.05 mm.

[0124] Example E12: An aerosol generating device according to any one of the preceding examples, wherein the first and second portions of the substrate are planar and non-coplanar, preferably wherein the angle between the normal to the planar first portion of the substrate and the normal to the planar second portion is between 60 degrees and 100 degrees, preferably between 70 degrees and 90 degrees, more preferably approximately 80 degrees.

[0125] Example E13: An aerosol generating device according to any one of the preceding examples, comprising an aerogel layer disposed between the substrate and the longitudinal central axis of the cavity, preferably wherein the aerogel layer has a thickness between 0.1 mm and 0.3 mm.

[0126] Example E14: An aerosol generating device according to any one of the preceding examples, wherein at least a portion of the substrate is flexible.

[0127] Example E15: An aerosol generating device according to Example E14, wherein the substrate further comprises a third portion between the first and second portions, and wherein at least the third portion is flexible such that the first portion is movable relative to the second portion, preferably wherein the metal backing layer is not provided on the surface of the second outer layer of the third portion of the substrate.

[0128] Example E16: An aerosol generating device according to Example E15, wherein the flexible portion is configured such that the emitter is movable relative to the sensor by bending the flexible portion.

[0129] Example E17: An aerosol generating device according to Example E16, wherein the substrate is bent such that the angle between the central optical axis of the emitter and the central optical axis of the sensor is between 20 degrees and 120 degrees, preferably between 60 degrees and 100 degrees, more preferably between 70 degrees and 90 degrees, more preferably approximately 80 degrees.

[0130] Example E18: An aerosol generating device according to any one of the preceding examples, comprising a shielding plate configured to block electromagnetic radiation and positioned outside the cavity such that the sensor is disposed between the longitudinal central axis of the cavity and at least a portion of the shielding plate, preferably wherein the sensor is positioned between a first portion of the shielding plate and the cavity, and the emitter is positioned between a second portion of the shielding plate and the cavity.

[0131] Example E19: An aerosol generating device according to any one of the preceding examples, wherein during operation of the device, the temperature of the sensing assembly does not exceed 120 degrees Celsius, preferably does not exceed 110 degrees Celsius, more preferably does not exceed 100 degrees Celsius, more preferably does not exceed 95 degrees Celsius, more preferably does not exceed 90 degrees Celsius, more preferably does not exceed 87 degrees Celsius.

[0132] Example E20: An aerosol-generating device according to any one of the preceding examples, wherein the chamber is defined by a housing of the device, and wherein a first part of the housing is penetrable to electromagnetic radiation of at least some wavelengths emitted by the emitter, and wherein the emitter is configured to emit the electromagnetic radiation into the chamber through the penetrable part.

[0133] Example E21: An aerosol-generating device according to any one of the preceding examples, wherein the sensing assembly further comprises amplification electronics directly connected to the sensor.

[0134] Example E22: An aerosol-generating device according to any one of the preceding examples, further comprising a controller configured to receive a signal from the sensor, wherein the controller is configured to determine a material property of at least part of the aerosol-forming substrate or an aerosol-generating article comprising the aerosol-forming substrate received in the chamber based on a measured intensity of the electromagnetic radiation received at the sensor.

[0135] Example E23: The aerosol-generating device according to Example E22, wherein the material property determined by the controller comprises the humidity or water content of the aerosol-forming substrate.

[0136] Example E24: An aerosol-generating system comprising an aerosol-generating device according to any one of the preceding examples and an aerosol-generating article comprising the aerosol-forming substrate.

[0137] Features described with respect to one embodiment may equally apply to other embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0138] The present invention will be further described by way of example only with reference to the accompanying drawings, in which:

[0139] Figure 1 An aerosol-generating system is shown;

[0140] Figure 2 a and 2b show the sensing assembly;

[0141] Figure 3 The sensing assembly is shown;

[0142] Figure 4 a and 4b show a multilayer substrate;

[0143] Figure 5 a and 5b show a multilayer substrate. DETAILED DESCRIPTION

[0144] Figure 1The aerosol generating system 10 is shown in cross - section. The aerosol generating system 10 includes an aerosol generating article 12. The aerosol generating article 12 includes an aerosol - forming substrate 14 at its distal portion. The aerosol generating system 10 also includes an aerosol generating device 20. The aerosol generating device 20 includes a chamber 22 for receiving the aerosol - forming substrate 14. The chamber 22 is defined by a housing 24 of the aerosol generating device 20.

[0145] In Figure 1 the configuration shown, the distal portion of the aerosol generating article 12 including the aerosol - forming substrate 14 has been inserted into the chamber 22. The aerosol - forming substrate 14 may be a solid tobacco - containing substrate. In particular, the aerosol - forming substrate 14 may be an aggregated sheet of homogenized tobacco.

[0146] As Figure 1 shown, the aerosol generating article 12 and the chamber 22 are configured such that when the aerosol generating article 12 is received in the chamber 22, the mouth end of the aerosol generating article 12 protrudes outside the chamber 22 and outside the aerosol generating device 16. This mouth end forms a mouthpiece 16 on which a user of the aerosol generating device can draw during use.

[0147] The aerosol generating device 20 includes a heater assembly, and the heater assembly includes a heating element 26. The heating element 26 surrounds a portion of the chamber 22 along which the aerosol - forming substrate 14 of the aerosol generating article 12 is received. In an alternative embodiment, the heating element 26 may form a part of the housing 24 that defines the portion of the chamber 22 for receiving the aerosol - forming substrate 14. The heating element 26 may be a resistive heating element.

[0148] An air flow channel 28 extends from an air inlet 30 of the aerosol generating device 20. Upstream of the chamber 22, the air flow channel 28 is mainly defined by an air flow channel wall 32. Downstream of the air flow channel wall 32, the air flow channel 28 passes through an air inlet defined in a base 34 of the chamber 22. Then the air flow channel 28 extends through the chamber 22. When the aerosol generating article 12 is received in the chamber 22, the air flow channel 28 passes through the aerosol generating article 12 and extends through the mouthpiece 16.

[0149] The aerosol generating device 20 also includes a power source 36 in the form of a rechargeable battery for powering the heating element 26 controllable by a controller 38. The power source 36 is connected to the controller 38 and the heating element 26 via wires and connectors not shown in the figure. The aerosol generating device 20 may include other elements not shown in the figure, such as a button for activating the aerosol generating device 20.

[0150] The aerosol generating device 20 also includes a sensing assembly 40 for detecting the aerosol - forming substrate 14 in the chamber 22.

[0151] Figure 2 a shows the sensing assembly 40 more clearly. Figure 2 a is a perspective view of a cut-away portion of the sensing assembly 40 with the aerosol-generating device 20.

[0152] The sensing assembly 40 includes a transmitter 42. The transmitter 42 includes a plurality of LEDs. Each of these LEDs is configured to emit electromagnetic radiation of a different wavelength. The transmitter 42, and in particular the plurality of LEDs of the transmitter 42, is configured to emit electromagnetic radiation into the cavity 22. The transmitter 42 is configured to emit electromagnetic radiation having a wavelength between 1350 and 1400 nanometers.

[0153] As Figure 1 shown, the housing 24 that defines a portion of the cavity 22 includes a first penetrable portion 23. The transmitter 42 is separated from the cavity 22 by the first penetrable portion 23 and is configured to emit electromagnetic radiation into the cavity 22 through the first penetrable portion 23. The provision of the first penetrable portion 23 protects the transmitter 42 from debris and dirt that may accumulate in the cavity 22 after long-term use of the device 20 and can be easily cleaned.

[0154] As Figure 2 shown in a, the sensing assembly 40 further includes a sensor 44. The sensor 44 is configured to receive electromagnetic radiation from the cavity 22. In particular, the sensor 44 is configured to receive electromagnetic radiation from the cavity 22 that is emitted by the transmitter 42 and then reflected or transmitted by the aerosol-generating article 12 towards the sensor 44. The sensor 44 includes a photodiode. The sensor 44 is configured to measure the received electromagnetic radiation at a plurality of wavelengths. In particular, the sensor 44 is configured to measure the intensity of the received electromagnetic radiation at a plurality of wavelengths. The sensor 44 is configured to receive electromagnetic radiation having a wavelength between 1350 and 1400 nanometers.

[0155] The cavity 22 includes a second penetrable portion not shown in the figure. The sensor 44 is separated from the cavity 22 by the second penetrable portion and is configured to receive electromagnetic radiation from the cavity 22 through the second penetrable portion.

[0156] The sensing assembly 40 further includes a multilayer substrate 50 that includes a first outer layer defining a first side of the substrate 50 and a second outer layer defining a second side of the substrate 50. The transmitter 42 is disposed on the first outer layer on a first portion 52 of the substrate 50. The sensor 44 is disposed on the first outer layer on a second portion 54 of the substrate 50.

[0157] Both the first portion 52 and the second portion 54 of the substrate 50 are planar. The substrate 50 further includes a flexible third portion 56. As Figure 2As most clearly shown in FIGS. a and 3, the third part 56 has been bent such that the angle between the first part 52 and the second part 54 is 100 degrees. Accordingly, the angle between the normal of the first part 52 and the normal of the second part 54 is 80 degrees. This also means that the angle between the central optical axis of the emitter 42 and the central optical axis of the sensor 44 is 80 degrees (see Figure 2 b). This provides optimal optical performance.

[0158] The third part 56 is impermeable to electromagnetic radiation of each wavelength emitted by the emitter 42. This ensures that the electromagnetic radiation emitted by the emitter 42 is not directly received by the sensor 44. The substrate 50 includes additional flexible parts that allow the substrate 50 to be folded into Figure 2 the shape shown in FIGS. a and 3.

[0159] Figure 2 FIG. b shows the angle between the aerosol-generating article 12, the emitter 42, and the sensor 44. Figure 2 FIG. b is a cross-section of the aerosol-generating article 12, the emitter 42, and the sensor 44 separated from the rest of the device 20. The optimal angle between the central optical axis 42a of the emitter 42 and the central optical axis 44a of the sensor 44 is 80 degrees. This angle is indicated by the numeral 43 in Figure 2 FIG. b.

[0160] Figure 3 Another cross-sectional perspective view of a section of the aerosol-generating device 20 including the sensing assembly 40 is shown (but viewed towards the cavity from a direction approximately opposite to that in Figure 2 FIG. a). Figure 3 Several parts of the sensing assembly 40 are shown in an exploded view, namely the shielding plate 60, the substrate 50, and the aerogel layer 86.

[0161] In the assembled configuration, these components are attached on top of each other. The aerogel layer 86 is disposed between the substrate 50 and the longitudinal central axis 21 of the cavity 22. The aerogel layer 86 has a thickness of approximately 0.2 millimeters.

[0162] The shielding plate 60 is configured to block electromagnetic radiation and is positioned outside the cavity such that the sensor 44 is disposed between at least a portion of the cavity 22 and the shielding plate 60. In the illustrated embodiment, both the sensor 44 and the emitter 42 are positioned between the shielding plate 60 and the cavity 22. In this way, electromagnetic radiation outside the cavity 22 and the sensing assembly 40 is prevented from reaching the emitter 42, and more importantly, from reaching the sensor 44. This means that the amount of external electromagnetic radiation received at the sensor 44 is significantly reduced or eliminated and is thus not detected as noise at the sensor 44.

[0163] The shielding plate 60 is rigid enough such that it can hold and maintain the first part 52 of the substrate 50 relative to the second part 54, such that the angle between the normal of the first part 52 and the normal of the second part 54 is 80 degrees.

[0164] The shielding plate 60 includes a first clamp 82 at a first end and a second clamp 84 at a second end, the first end being at an end of the shielding plate 60 opposite the second end. The first clamp 82 and the second clamp 84 are configured to connect the shielding plate 60 to the substrate 50.

[0165] As Figure 1 is visible, the sensing assembly 40 is positioned relatively close to the heating element 26. Thus, during use of the aerosol-generating device 20, when current passes through the heating element 26 and heats it, heat will inevitably be transferred from the heating element 26 to the sensing assembly 40. The emitter 42 and the sensor 44 may be damaged when they overheat. A heat dissipation structure of the sensing assembly 40 that dissipates heat from the emitter 42 and the sensor 44 can reduce the risk of damage to the emitter 42 and the sensor 44. This will now be explained in more detail.

[0166] Figure 4 a shows the substrate 50 separately from the rest of the aerosol-generating device 20 and laid flat. The substrate 50 of the sensing assembly 40 also includes analog amplification electronics 57, which are configured to amplify the signal generated by the sensor 44. The amplification electronics 57 are attached to a fourth part of the substrate 50. By disposing the amplification electronics 57 and the sensor 44 on the same printed circuit board (PCB) of the substrate 50, a direct electrical connection can be established between the amplification electronics 57 and the sensor 44. This minimizes the number of electrical connections between the amplification electronics 57 and the sensor 44 and thus minimizes the amount of noise introduced into the signal generated by the sensor 44 before those signals are amplified.

[0167] The substrate 50 also includes a connector 58. The connector 58 is used to connect the substrate 50 to the electronics of the rest of the aerosol-generating device 20, in particular the controller 38 and the power supply 36.

[0168] The substrate 50 also includes an extended end portion 59 of the substrate 50 positioned adjacent to the second part 54. The extended end portion 59 extends beyond the second part 54 by approximately 16 millimeters and has no conductive tracks on its surface. The extended end portion 59 serves as a heat dissipation structure to dissipate heat from the sensor 44 during use.

[0169] The flexible third part 56 of the substrate 50 has been described. The substrate 50 includes additional flexible parts that allow the substrate 50 to be folded into Figure 2 a and Figure 3 the shape shown.

[0170] Figure 4 Figure b shows an embodiment of the substrate 50 that is separate from the remainder of the aerosol generating device 20 and is arranged flat. Figure 4 The substrate 50 of Figure b is different from Figure 4 the substrate 50 of Figure a in that Figure 4 the substrate 50 of Figure b further includes a metal backsheet layer 90 disposed on the rear surface (i.e., the second outer layer) of the substrate 50, as indicated by the arrow in Figure 4 Figure b. The metal backsheet layer 90 includes a first metal plate 92 and a second metal plate 94. The first metal plate 92 and the second metal plate 94 are made of stainless steel, preferably JIS SUS304 steel. Each of the first metal plate 92 and the second metal plate 94 has a width of about 0.4 mm and a length of about 1.0 mm. The first metal plate 92 is disposed at the rear side of the first portion 52 of the substrate 50 opposite to the emitter 42. The second metal plate 94 is disposed at the rear side of the second portion 54 of the substrate 50 opposite to the sensor 44.

[0171] The metal backsheet layer 90 serves as a heat dissipation structure to dissipate heat from the emitter 42 and the sensor 44 during use. Additionally, the metal backsheet layer 90 acts as a reinforcement to provide mechanical stability to the first portion 52 and the second portion of the substrate 50.

[0172] Figure 5 Figure a shows a sub-section of the substrate 50 including a part of the second portion 54 and an extended end portion 59 in a top view. The second portion 54 includes conductive tracks 503 on its surface. The extended end portion 59 does not have any conductive tracks on its surface. The extended end portion 59 extends beyond the second portion 54 by a distance of at least 5 mm, which is indicated by the double-ended arrow in Figure 5 Figure a.

[0173] Figure 5 Figure b shows a cross-section of a sub-section of the substrate 50 including a part of the second portion 54, the extended end portion 59, and the metal backsheet layer 90. The metal backsheet layer 90 has a thickness of about 0.3 mm.

[0174] Figure 5 Figure b shows that the multi-layer substrate 50 includes a first outer layer 502 that defines the first side of the substrate 50. The first outer layer 502 is a PCB that includes conductive tracks 503 in the region of the second portion 54 but not in the region of the extended end portion 59. The sensor 44 is attached to the first outer layer 502 in the region of the second portion 54 and is electrically connected via the conductive tracks 503. The multi-layer substrate 50 includes a second outer layer 504 that defines the second side of the substrate 50. The second outer layer 504 of the substrate 50 is a PCB.

[0175] The substrate 50 further includes an intermediate layer 506 disposed between the first outer layer 502 and the second outer layer 504. The intermediate layer 506 is a copper layer.

[0176] The extended end portion 59 of the substrate 50 further includes a copper intermediate layer 506 disposed between the first outer layer 502 and the second outer layer 504. However, the metal backing layer 90 is not provided on the surface of the second outer layer 504 of the substrate 50 in the region of the extended end portion 59.

[0177] As Figure 1 shown, when using the aerosol generating device 20, the aerosol generating article 12 is received in the cavity 22. The sensing assembly 40 in combination with the controller 38 is capable of detecting the presence of the aerosol generating article 12. The emitter 42 of the sensing assembly 40 emits electromagnetic radiation of multiple wavelengths. Then, the radiation is reflected and / or transmitted by the aerosol generating article 12. Since the viewing angles of the emitter 42 and the sensor 44 substantially overlap when the angle between the central optical axis of the emitter 42 and the central optical axis of the sensor 44 is 80 degrees, a large amount of the reflected and / or transmitted electromagnetic radiation is received by the sensor 44. The sensor 44 measures the intensity of the received electromagnetic radiation of various wavelengths. In this way, the sensor 44 generates an electrical signal. These electrical signals are directly transmitted to the amplification electronics to be amplified before being received at the controller 38. The controller 38 is configured to perform a spectral analysis on the measured values of the intensity of the electromagnetic radiation of different wavelengths. This includes comparing the intensity of the electromagnetic radiation of different wavelengths with a known intensity distribution emitted by the emitter 42. Based on the spectral analysis, the controller 38 is configured to determine whether the aerosol generating article 12 is present.

[0178] The controller 38 is further configured to determine the type of the aerosol generating article 12 based on the spectral analysis. Different types of aerosol generating articles 12 can be received in the cavity 22. In particular, aerosol generating articles 12 having aerosol-forming substrates 14 with different chemical properties can be received in the cavity 22. Since the aerosol generating article 12 and the aerosol-forming substrate have different chemical and / or other material properties, different aerosol generating articles 12 will reflect or transmit the electromagnetic radiation of multiple wavelengths emitted by the emitter 42 to different extents. This will mean that the spectrum of the electromagnetic radiation received by the sensor 44 will be different for different aerosol generating articles 12. The spectrum of a specific type of aerosol generating article 12 is predictable. Therefore, based on the spectral analysis, the controller 38 can determine the type of the aerosol generating article 12 received in the cavity 22.

[0179] The controller 38 is configured to control the heating element 26 according to an appropriate heating curve for the determined type of the aerosol generating article 12.

[0180] Based on this spectral analysis, the controller 38 is also configured to determine the material properties of the aerosol-generating article 12 received in the chamber 22. In particular, the controller 38 is configured to determine the material properties of the aerosol-forming substrate 14 of the aerosol-generating article 12. The material property determined by the controller 38 is the humidity or water content of the aerosol-forming substrate.

[0181] The controller 38 is configured to determine a value related to the water content of the aerosol-forming substrate 14 received in the chamber 22 based on the measured intensity of the electromagnetic radiation received at the sensor 44. As described above, the emitter 42 and the sensor 44 are respectively configured to emit and receive electromagnetic radiation having a wavelength between 1350 nanometers and 1400 nanometers. Water is particularly effective in absorbing electromagnetic radiation in this range. Therefore, the intensity of the radiation received by the sensor 44 highly depends on the water content of the aerosol-forming substrate 14, and the controller 38 is capable of determining a value associated with the water content of the aerosol-forming substrate 14 based on the spectral analysis of the electromagnetic radiation received by the sensor 44.

Claims

1. An aerosol generating device, the aerosol generating device comprising a chamber for receiving an aerosol-forming substrate and a sensing assembly for detecting the aerosol-forming substrate in the chamber; the sensing assembly comprising a multilayer substrate, the multilayer substrate comprising a first outer layer defining a first side of the substrate and a second outer layer defining a second side of the substrate; A transmitter configured to emit electromagnetic radiation into the cavity and disposed on the first outer layer on the first portion of the substrate; A sensor configured to measure the received electromagnetic radiation at at least one wavelength and disposed on the first outer layer on the second portion of the substrate; And At least one heat dissipation structure selected from: - A metal backplane layer disposed on the surface of the second outer layer of the substrate, and - An extended end portion of the substrate positioned adjacent to the first portion or adjacent to the second portion, the extended end portion extending beyond the first portion or the second portion by at least 5 millimeters and having no conductive tracks on the surface of the extended end portion.

2. The aerosol generating device according to claim 1, wherein the substrate comprises one or more printed circuit boards, preferably one or more flexible printed circuit boards.

3. The aerosol generating device according to claim 1 or claim 2, wherein the substrate comprises an intermediate layer disposed between the first outer layer and the second outer layer, preferably wherein the first outer layer and the second outer layer of the substrate are printed circuit boards.

4. The aerosol generating device according to claim 3, wherein the intermediate layer is a metal layer, preferably wherein the intermediate layer comprises copper, more preferably wherein the intermediate layer is a copper layer.

5. The aerosol generating device according to any one of the preceding claims, comprising an extended end portion of the substrate, wherein the extended end portion comprises a copper layer, preferably wherein the copper layer is an intermediate layer disposed between the first outer layer and the second outer layer.

6. The aerosol generating device according to any one of the preceding claims, comprising an extended end portion of the substrate positioned adjacent the first portion or adjacent the second portion, wherein the extended end portion extends beyond the first portion or the second portion by at least 10 millimeters, preferably at least 12 millimeters, more preferably at least 14 millimeters, and more preferably a distance between 14 millimeters and 17 millimeters.

7. The aerosol generating device according to any one of the preceding claims, comprising both the extended end portion of the substrate and the metal backing layer, and wherein the metal backing layer is not disposed on the surface of the second outer layer of the substrate in the region of the extended end portion.

8. The aerosol generating device according to any one of the preceding claims, comprising the metal backing layer, wherein the metal backing layer is a steel layer, preferably a stainless steel layer, more preferably wherein the steel is JIS SUS304.

9. The aerosol generating device according to any one of the preceding claims, comprising the metal backing layer, wherein the metal backing layer has a thickness between 0.1 mm and 0.5 mm, preferably between 0.2 mm and 0.4 mm, more preferably between 0.25 mm and 0.35 mm.

10. The aerosol generating device according to any one of the preceding claims, comprising the metal backing layer, wherein the metal backing layer comprises a first separate metal plate and a second separate metal plate, preferably wherein the first metal plate is disposed on a first portion of a second outer layer of the substrate opposite a first portion of a first outer layer of the substrate, and the second metal plate is disposed on a second portion of the second outer layer of the substrate opposite a second portion of the first outer layer of the substrate.

11. The aerosol generating device according to claim 10, wherein each of the first metal plate and the second metal plate has a width between 0.2 mm and 0.6 mm, preferably between 0.35 mm and 0.45 mm, and a length between 0.7 mm and 1.3 mm, preferably between 0.95 mm and 1.05 mm.

12. The aerosol generating device according to any one of the preceding claims, wherein the first and second portions of the substrate are planar and non-coplanar, preferably wherein the angle between the normal of the planar first portion of the substrate and the normal of the planar second portion is between 60 degrees and 100 degrees, preferably between 70 degrees and 90 degrees, more preferably about 80 degrees.

13. The aerosol generating device according to any one of the preceding claims, comprising an aerogel layer disposed between the substrate and the longitudinal central axis of the cavity, preferably wherein the aerogel layer has a thickness between 0.1 mm and 0.3 mm.

14. The aerosol generating device according to any one of the preceding claims, wherein at least a portion of the substrate is flexible.

15. The aerosol generating device according to claim 14, wherein the substrate further comprises a third portion between the first portion and the second portion, and wherein at least the third portion is flexible such that the first portion is movable relative to the second portion, preferably wherein the metal backing layer is not disposed on the surface of the second outer layer of the third portion of the substrate.

16. The aerosol generating device according to claim 15, wherein the flexible portion is configured such that the emitter is movable relative to the sensor by bending the flexible portion.

17. The aerosol-generating device according to claim 16, wherein the substrate is bent such that the angle between the central optical axis of the emitter and the central optical axis of the sensor is between 20 degrees and 120 degrees, preferably between 60 degrees and 100 degrees, more preferably between 70 degrees and 90 degrees, and even more preferably about 80 degrees.

18. The aerosol-generating device according to any one of the preceding claims, comprising a shielding plate configured to block electromagnetic radiation and positioned outside the cavity such that the sensor is arranged between the longitudinal central axis of the cavity and at least a part of the shielding plate, preferably wherein the sensor is positioned between a first part of the shielding plate and the cavity, and the emitter is positioned between a second part of the shielding plate and the cavity.

19. The aerosol-generating device according to any one of the preceding claims, wherein during operation of the device, the temperature of the sensing assembly does not exceed 120 degrees Celsius, preferably does not exceed 110 degrees Celsius, more preferably does not exceed 100 degrees Celsius, more preferably does not exceed 95 degrees Celsius, more preferably does not exceed 90 degrees Celsius, and even more preferably does not exceed 87 degrees Celsius.

20. The aerosol-generating device according to any one of the preceding claims, wherein the cavity is defined by a housing of the device, and wherein a first part of the housing is penetrable to electromagnetic radiation of at least some wavelengths emitted by the emitter, and wherein the emitter is configured to emit the electromagnetic radiation into the cavity through the penetrable part.

21. The aerosol-generating device according to any one of the preceding claims, wherein the sensing assembly further comprises amplification electronics directly connected to the sensor.

22. The aerosol-generating device according to any one of the preceding claims, further comprising a controller configured to receive a signal from the sensor, wherein the controller is configured to determine a material property of the aerosol-forming substrate or an aerosol-generating article comprising the aerosol-forming substrate received at least partially in the cavity based on a measured intensity of the electromagnetic radiation received at the sensor.

23. The aerosol-generating device according to claim 22, wherein the material property determined by the controller comprises the humidity or water content of the aerosol-forming substrate.

24. An aerosol-generating system, comprising an aerosol-generating device according to any one of the preceding claims and an aerosol-generating article comprising the aerosol-forming substrate.

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