Aerosol generating device with a sensing assembly having a heat dissipation structure

Abstract

The present invention relates to an aerosol generating device comprising a cavity for receiving an aerosol-forming substrate and a sensing assembly for detecting the aerosol-forming substrate within the cavity. The sensing assembly comprises a 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; an emitter configured to emit electromagnetic radiation into the cavity and provided on the first outer layer on a first portion of the substrate; a sensor configured to measure at least one wavelength of the received electromagnetic radiation and provided on the first outer layer on a second portion of the substrate; and at least one heat dissipation structure selected from a metal backing layer provided 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 the second portion. The extended end portion extends at least 5 millimeters beyond the first or second portion and does not include a conductive track on its surface.

Description

[Technical Field]

[0001] The present invention relates to an aerosol generating device. The present invention further relates to an aerosol generating system. [Background technology]

[0002] It is known to provide aerosol-generating devices for generating 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.

[0003] Aerosol-generating devices often include several electronic components to enable different functions of the device. During use, the temperature of these electronic components may rise to undesirably high temperatures due to heat conduction from the high-temperature heating chamber. This may be particularly serious for electronic components that must be located in close proximity to the heating chamber and cannot tolerate very high temperatures. For example, optical components may be positioned near the opening of the heating chamber to identify the insertion of an aerosol-generating article into the heating chamber. At the same time, electronic components such as optical components often may not operate at temperatures that are too high.

[0004] It would therefore be desirable to provide an aerosol generating device that reduces the temperature rise of electronic components during use.It would be desirable to provide an aerosol generating device with improved heat dissipation. Summary of the Invention

[0005] According to an embodiment of the present invention, there is provided an aerosol generating device. The aerosol generating device may comprise a cavity for receiving an aerosol-forming substrate. The aerosol generating device may comprise a sensing assembly for sensing the aerosol-forming substrate in the cavity. The sensing assembly may comprise a multi-layer substrate. The multi-layer substrate may comprise a first outer layer defining a first side of the substrate. The multi-layer substrate may comprise a second outer layer defining a second side of the substrate. The sensing assembly may comprise an emitter configured to emit electromagnetic radiation into the cavity. The emitter may be provided on the first outer layer on a first portion of the substrate. The sensing assembly may comprise a sensor configured to measure at least one wavelength of the received electromagnetic radiation. The sensor may be provided on the first outer layer on a second portion of the substrate. The sensing assembly may comprise at least one heat dissipation structure. The heat dissipation structure may be selected from a metal backing layer provided 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 at least 5 millimeters beyond said first or second portion. The extended end portion may be free of conductive tracks on its surface.

[0006] According to an embodiment of the present invention, an aerosol generating device is provided. The aerosol generating device comprises a cavity for receiving an aerosol-forming substrate and a sensing assembly for detecting the aerosol-forming substrate in the cavity. The sensing assembly comprises a multi-layer substrate. The multi-layer substrate comprises 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 comprises an emitter configured to emit electromagnetic radiation into the cavity. The emitter is provided on the first outer layer on a first portion of the substrate. The sensing assembly comprises a sensor configured to measure at least one wavelength of the received electromagnetic radiation. The sensor is provided on the first outer layer on a second portion of the substrate. The sensing assembly comprises 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 provided on a surface of the second outer layer of the substrate. The extended end portion is located adjacent to the first portion or adjacent to the second portion. The extended end portion extends at least 5 millimeters beyond said first or second portion. The outer surface of the extended end portion of the substrate does not include a conductive track.

[0007] The sensing assembly may comprise a metal backing layer. The sensing assembly may comprise 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] A sensing assembly comprising at least one heat dissipation structure may provide an aerosol generating device with reduced temperature rise of electronic components during use. A sensing assembly comprising at least one heat dissipation structure may provide an aerosol generating device with improved heat dissipation.

[0009] An aerosol-generating device equipped with a sensing assembly may advantageously be able to detect the presence and type of an aerosol-generating substrate at least partially received within the cavity based on measurements of at least one wavelength of received electromagnetic radiation produced by the sensor. The aerosol-forming substrate may be included in an aerosol-generating article at least partially received within the cavity. During use, the emitter may advantageously emit electromagnetic radiation into the cavity in which the aerosol-forming substrate is at least partially received. Electromagnetic radiation incident on the aerosol-forming substrate or aerosol-generating article may undergo one of absorption, reflection, or transmission. The amount of absorption, reflection, or transmission of electromagnetic radiation at different wavelengths may depend on the chemical structure of the aerosol-forming substrate or article. Thus, the chemical structure of the aerosol-forming substrate or article may affect the electromagnetic radiation received from the cavity by the sensor. Different aerosol-forming substrates or articles may have different chemical structures and therefore may affect the electromagnetic radiation differently. Thus, measurements of the received electromagnetic radiation may advantageously be used to determine the presence and type of an aerosol-forming substrate received within the cavity.

[0010] The sensor is preferably configured to measure the intensity of at least one wavelength of electromagnetic radiation. Measuring may include comparing the intensity of the at least one wavelength of electromagnetic radiation to a threshold value.

[0011] With a sensing assembly comprising at least one heat dissipation structure of the present invention, the temperature rise of the sensing assembly during use can be reduced due to the heat dissipation function of the at least one heat dissipation structure.

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

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

[0014] The cavity may include a second end opposite the first end, and the second end may include a base of the cavity.

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

[0016] The emitter and sensor may be positioned along the longitudinal axis of the cavity distal to the second end of the cavity, and may be positioned to direct electromagnetic radiation toward and receive electromagnetic radiation from the second end of the cavity, respectively.

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

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

[0019] The first and second portions of the substrate may be planar. The first and second portions of the substrate may not be coplanar. The angle between the normal to the planar first portion and the normal to the planar second portion of the substrate may be 60 to 100 degrees, preferably 70 to 90 degrees, and more preferably about 80 degrees.

[0020] The substrate has a first side to which at least one of the emitter and the sensor is attached. The substrate may have a second side opposite the first side to which a shield plate is attached. This may advantageously be a simple arrangement that is easy to manufacture. The substrate may comprise one or more printed circuit boards (PCBs). The substrate may be a printed circuit board (PCB). The substrate may comprise two or more PCBs. The substrate may include or consist of one or more flexible PCBs.

[0021] The substrate may include a flexible portion. The flexible portion may be configured so that the emitter can be moved relative to the sensor by bending the flexible portion. The angle between the sensor and the emitter may be 20 to 120 degrees, preferably 60 to 100 degrees, and even more preferably 70 to 90 degrees. Most preferably, the angle between the sensor and the emitter may be approximately 80 degrees. A substrate including a flexible portion may 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 may advantageously eliminate the need to pre-shape the substrate into a desired shape. It may be possible to modify the angle between the emitter and the sensor during or after manufacturing of the aerosol-forming device. When the angle between the emitter and the sensor is referred to herein, the angle is defined as the angle between the central optical axis of the emitter and the central optical axis of the sensor. This may be the same as the angle defined between the emitter and the sensor and the surface of the aerosol-forming substrate or article at least partially received within the cavity. The angle between a normal to the plane of the first portion and a normal to the plane of the second portion may be substantially the same as the angle between the sensor and the emitter.

[0022] The substrate may be angled so that the emitter is adjacent to a different portion of the cavity than the sensor, and the angle between the central optical axis of the emitter and the sensor is 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 may be about 80 degrees.

[0023] The substrate may include a third portion between the first and second portions, and at least the third portion may be flexible such that the first portion is movable relative to the second portion, which may allow for control of the angle between the emitter and the sensor, as described above.

[0024] Preferably, no metal backing layer is provided on the surface of the second outer layer of the third portion of the substrate.

[0025] Preferably, the first portion of the substrate may be rigid, the second portion of the substrate may be rigid, and the flexible third portion thus acts as a hinge between the rigid first and second portions.

[0026] The third portion of the substrate may preferably be opaque to the wavelength of the electromagnetic radiation emitted by the emitter, which may advantageously ensure that the electromagnetic radiation emitted by the emitter is not directly received by the sensor before being reflected or absorbed and emitted by the aerosol-forming substrate received within the cavity.

[0027] The substrate may comprise one or more PCBs. The substrate may consist of one or more flexible PCBs. At least a third portion of the substrate may include or consist of a flexible PCB.

[0028] Preferably, the first and second portions of the substrate may comprise rigid PCBs, and the third portion may comprise a flexible PCB.

[0029] The shield plate may include a planar first portion and a planar second portion. The first and second planar portions of the shield plate may not be coplanar. The first portion of the shield plate may be coplanar with the first portion of the substrate. The second portion of the shield plate may be coplanar with the second portion of the substrate.

[0030] The sensor may be positioned between the first portion of the shield plate and the cavity, and the emitter may be positioned between the second portion of the shield plate and the cavity.

[0031] A particularly preferred combination may be a base comprising a flexible portion as described above and a shield plate as described above, when the shield plate comprises first and second planar portions, the second portion being planar in a different plane than the first portion, since the shield plate may advantageously hold the base so that the flexible portion can bend at a desired angle.

[0032] The shield plate may preferably be attached to a second side of the base opposite the first side. The shield plate may be rigid.

[0033] A first portion of the shield plate may be attached to a first portion of the substrate, and a second portion of the shield plate may be attached to a second portion of the substrate.

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

[0035] The shield plate may include at least one clip. The shield plate may include a first clip at a first end and a second clip at a second end. The first end may be located at an end of the shield plate opposite the second end. The one or more clips may be configured to connect the clip to a second side of the base. The one or more clips may advantageously provide a simple and low-cost means of mounting the shield plate on the base. Mounting the shield plate on the base in this manner may advantageously ensure simple and low-cost manufacturing of the sensing assembly.

[0036] The shield plate may be connected to a ground contact of the aerosol generating device. The ground contact may be on the substrate. If the substrate comprises a PCB, the ground contact may be on the PCB. At least one clip of the shield plate may contact the ground contact. Connecting the shield plate to the ground contact may enable the shield plate to provide good shielding.

[0037] The shield plate may be integrally formed and may include at least one clip. The shield plate may be a single plate and may include at least one clip.

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

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

[0040] The extended end portion of the substrate may include a metal layer or an alloy layer. The metal layer or alloy layer may be an intermediate layer disposed between the first outer layer and the second outer layer. The metal layer or 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 base is located adjacent to the first portion or adjacent to the second portion. When the extended end portion is located adjacent to the first portion, the first portion is located between the extended end portion and the second portion. When the extended end portion is located adjacent to the second portion, the second portion is located between the extended end portion and the first portion.

[0042] The extended end portion of the substrate located adjacent the first portion of the substrate may extend beyond the first 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, more preferably between 14 millimeters and 17 millimeters.

[0043] When the extended end portion of the substrate is located adjacent to the second portion of the substrate, the extended end portion of the substrate may 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, more preferably between 14 millimeters and 17 millimeters.

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

[0045] The metal backing layer may be a steel layer. The metal backing layer may be a stainless steel layer. The steel may be steel conforming to Japanese Steel Standard JIS SUS304.

[0046] The thickness of the metal backing layer is between 0.1 millimeters and 0.5 millimeters, preferably between 0.2 millimeters and 0.4 millimeters, more preferably between 0.25 millimeters and 0.35 millimeters, and more preferably about 0.3 millimeters.

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

[0048] The width of the first metal plate is 0.2 mm to 0.6 mm, preferably 0.35 mm to 0.45 mm, and more preferably about 0.4 mm. The length of the first metal plate is 0.7 mm to 1.3 mm, preferably 0.95 mm to 1.05 mm, and more preferably about 1.0 mm. The first metal plate may have a thickness of preferably 0.1 mm to 0.5 mm, more preferably 0.2 mm to 0.4 mm, more preferably 0.25 mm to 0.35 mm, and more preferably about 0.3 mm.

[0049] The width of the first metal plate is 0.2 mm to 0.6 mm, preferably 0.35 mm to 0.45 mm, and more preferably about 0.4 mm. The length of the first metal plate is 0.7 mm to 1.3 mm, preferably 0.95 mm to 1.05 mm, and more preferably about 1.0 mm. The thickness of the second metal plate is preferably 0.1 mm to 0.5 mm, more preferably 0.2 mm to 0.4 mm, more preferably 0.25 mm to 0.35 mm, and more preferably about 0.3 mm.

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

[0051] The sensing assembly may include an aerogel layer or aerogel sheet. The aerogel layer or 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 aerogel sheet. The aerogel layer or 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 aerogel sheet may have a thickness of 0.1 to 0.3 millimeters, preferably about 0.2 millimeters. The aerogel layer or aerogel sheet may function as a thermal barrier. The aerogel layer or aerogel sheet may help insulate the substrate from the heater assembly. The aerogel layer or aerogel sheet may help insulate the substrate from the cavity when at least a portion of the cavity is heated during use of the aerosol generating device.

[0052] The cavity may be defined within a housing of the aerosol generating device. The aerosol generating device housing defining the cavity may comprise a first housing portion defining the cavity. The first housing portion defining the cavity may be transparent to at least one wavelength of electromagnetic radiation emitted from the emitter. It may be preferable that the first housing portion be transparent to all wavelengths of electromagnetic radiation emitted by the emitter. The emitter may be configured to emit electromagnetic radiation into the cavity through the transparent 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 within the cavity. In particular, the emitter may be protected from residue from the aerosol-forming substrate that may accumulate during use of the aerosol generating device. The first portion may also advantageously be easy to clean, allowing for easy maintenance of the device.

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

[0055] The first portion of the housing may be sized and positioned to correspond to the field of view angle of the emitter, which may advantageously ensure that substantially all of the electromagnetic radiation emitted by the emitter in use passes into the cavity.

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

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

[0058] Providing the first and second housing portions may advantageously extend the life of the sensing assembly. The first and second housing portions may protect the sensing assembly from degradation over time, for example, due to the accumulation of dirt, debris, and substrate residue. A degraded sensing assembly may reduce the amount of electromagnetic radiation entering the cavity from the emitter or received by the sensor from the cavity, 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 the aerosol-generating article is inserted. The open end may be a proximal end. The cavity may have a closed end opposite the open end. The closed end may be a base of the cavity. The closed end may be closed except for the provision of an air opening disposed within 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 disposed upstream of the cavity. The open end may be disposed downstream of the cavity. The cavity may have an elongated extension. The cavity may have a longitudinal central axis. The longitudinal axis may be a 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. A distal portion 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 cavity may have a shape corresponding to the shape of the aerosol-generating article to be received within the cavity. The cavity may have a circular cross-section. The cavity may have an elliptical or rectangular cross-section. The cavity may have an inner diameter corresponding to the outer diameter of the aerosol-generating article.

[0061] An airflow channel may extend through the cavity. Ambient air may be drawn through the airflow channel into the aerosol-generating device, into the cavity, and toward the user. Downstream of the cavity, a mouthpiece may be disposed, or the user may inhale the aerosol-generating article directly. The airflow 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] The aerosol generating device may include at least one lens configured to focus electromagnetic radiation received from the cavity onto the sensor. The lens may include an absorbing material that substantially blocks wavelengths of electromagnetic radiation outside a certain wavelength range. The absorbing material may be configured to substantially block wavelengths of electromagnetic radiation 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, thereby improving the accuracy of the sensing assembly in detecting the presence and type of aerosol-forming substrate at least partially received within the cavity.

[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 within the cavity based on the measured intensity of the electromagnetic radiation received by the sensor. The controller may be configured to determine a material property of an aerosol-generating article including the aerosol-forming substrate based on the measured intensity of the electromagnetic radiation received by the sensor.

[0066] Preferably, the controller may be configured to perform a spectral analysis of the measured intensity of the electromagnetic radiation to determine material properties of the aerosol-forming substrate or an aerosol-generating article comprising the aerosol-forming substrate. Based on the determined material properties, the controller may be configured to determine the type of aerosol-forming substrate at least partially received in the cavity. A controller configured to determine material properties of the aerosol-forming substrate may advantageously mean that the type of aerosol-forming substrate can be determined directly based on the inherent material properties of the aerosol-forming substrate. The aerosol-forming substrate, or an aerosol-generating article comprising the aerosol-forming substrate, does not need to include a printed barcode, taggant, or other indicia of the type of substrate.

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

[0068] The controller may include a memory. Stored in the controller's memory may be data relating known measurements of electromagnetic radiation at particular wavelengths to the chemical structure or type of the aerosol-forming substrate. The controller may be configured to determine the type of aerosol-forming substrate received in the cavity by comparing one or more electromagnetic radiation measurements made by the sensor at one or more wavelengths with 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 profile selected based on the determined type of aerosol-forming substrate.

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

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

[0071] The sensor may be configured to receive electromagnetic radiation having a wavelength between 1100 nanometers and 1500 nanometers. Preferably, the sensor may 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 wavelengths between 1100 nanometers and 1500 nanometers, especially between 1350 nanometers and 1400 nanometers. Therefore, it may be advantageous for the emitter and sensor to emit and receive these wavelengths of electromagnetic radiation when the target material property of the aerosol-forming substrate is wettability or water content.

[0073] The emitter may comprise at least one LED for emitting electromagnetic radiation. Preferably, the emitter may be configured to emit multiple wavelengths of electromagnetic radiation. The emitter may comprise multiple LEDs, each configured to emit a different wavelength of electromagnetic radiation.

[0074] The sensor may include a photodiode.

[0075] The sensor may be configured to receive multiple wavelengths of electromagnetic radiation, in particular, the sensor may be configured to measure multiple wavelengths of received electromagnetic radiation.

[0076] In other words, the sensing assembly may be configured to perform spectroscopy on an aerosol-forming substrate received in the cavity, or on an aerosol-generating article including a substrate received in the cavity. The apparatus may include a controller for performing spectral analysis on the measured electromagnetic radiation. Based on the spectral analysis, the controller may be configured to determine the presence of an aerosol-forming substrate in the cavity. The controller may be configured to determine the type of aerosol-forming substrate in the cavity.

[0077] As used herein, determining the presence and type of an aerosol-forming substrate is used interchangeably with determining the presence and type of an aerosol-generating article that includes the aerosol-forming substrate. In either case, the aerosol-generating device may advantageously be configured to determine the presence and type of the aerosol-forming substrate or article based on its chemical composition.

[0078] In one embodiment, the electromagnetic radiation emitted by the emitter may be incident on an aerosol-forming substrate, in which case the presence or type of aerosol-forming substrate may be determined.

[0079] Alternatively, the aerosol-forming substrate may be included in an aerosol-generating article. In that case, the electromagnetic radiation received by the sensor may be affected by the chemical structure of the aerosol-generating article, for example, the wrapper or housing of the article. Different aerosol-generating articles may have different chemical structures, for example, different wrappers or housings. This may make it possible to distinguish between different aerosol-generating articles.

[0080] "Different aerosol-generating articles" may refer to aerosol-generating articles that include different aerosol-forming substrates.

[0081] Furthermore, a portion of the electromagnetic radiation may pass through the aerosol-generating device to the aerosol-forming substrate such that the electromagnetic radiation received by the sensor may be affected by the chemical structure of both the aerosol-generating article and the substrate.

[0082] The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may comprise both solid and liquid components. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. Alternatively, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former that facilitates the formation of a dense and stable aerosol. Examples of suitable aerosol formers are glycerin and propylene glycol.

[0083] When the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of powder, granules, pellets, shreds, spaghetti, strips, or sheets containing one or more of herb leaves, tobacco leaves, tobacco stem fragments, reconstituted tobacco, homogenized tobacco, extruded tobacco, cast leaf tobacco, and expanded tobacco. The solid aerosol-forming substrate may be in loose form or may be provided in a suitable container or cartridge. Optionally, the solid aerosol-forming substrate may contain additional tobacco or non-tobacco volatile flavor compounds that are released upon heating of the substrate. The solid aerosol-forming substrate may also contain capsules, for example, containing additional tobacco or non-tobacco volatile flavor compounds, which may melt during heating of the solid aerosol-forming substrate.

[0084] As used herein, "homogenized tobacco" refers to a material formed by agglomerating particulate tobacco. The homogenized tobacco may be in the form of a sheet. The homogenized tobacco material may have an aerosol former content of greater than 5% on a dry weight basis. Alternatively, the homogenized tobacco material may have an aerosol former content of between 5% and 30% by weight on a dry weight basis. A sheet of homogenized tobacco material may be formed by agglomerating particulate tobacco obtained by grinding or otherwise combining one or both of tobacco lamina and tobacco stem. Alternatively, or additionally, the sheet of homogenized tobacco material may include one or more of tobacco dust, tobacco fines, and other particulate tobacco by-products formed, for example, during tobacco processing, handling, and shipping. The homogenized tobacco material sheet may include one or more inherent binders (i.e., tobacco intrinsic binders), one or more exogenous binders (i.e., tobacco extrinsic binders), or combinations thereof to aid in the cohesion of the particulate tobacco, although alternatively or additionally, the homogenized tobacco material sheet may include other additives, including, but not limited to, tobacco and non-tobacco fibers, aerosol formers, humectants, plasticizers, flavorants, fillers, aqueous and non-aqueous solvents, and combinations thereof.

[0085] Optionally, the solid aerosol-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may take the form of a powder, granules, pellets, pieces, spaghetti, strips, or sheets. Alternatively, the carrier may be a tubular carrier having a thin layer of solid substrate deposited on its inner surface, on its outer surface, or on both its inner and outer surfaces. Such a tubular carrier may be formed, for example, of paper or paper-like material, nonwoven carbon fiber mat, low-mass open-mesh metal screen, or perforated metal foil, or any other thermally stable polymeric matrix.

[0086] In a particularly preferred embodiment, the aerosol-forming substrate comprises an assembly of crimped sheets of homogenized tobacco material. As used herein, the term "crimped sheet" refers to a sheet having a plurality of substantially parallel ridges or corrugations. Preferably, when the aerosol-generating article is assembled, the substantially parallel ridges or corrugations extend along or parallel to the longitudinal axis of the aerosol-generating article. This advantageously facilitates assembling the crimped sheets of homogenized tobacco material to form the aerosol-forming substrate. However, it will be appreciated that a crimped sheet 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 relative to the longitudinal axis of the aerosol-generating article when the aerosol-generating article is assembled. In certain embodiments, the aerosol-forming substrate may comprise an assembly of sheets of homogenized tobacco material that are substantially uniformly textured across substantially its entire surface. For example, the aerosol-forming substrate may comprise an assemblage of a crimped sheet of homogenized tobacco material that includes a plurality of substantially parallel ridges or corrugations that are substantially evenly spaced across the width of the sheet.

[0087] The solid aerosol-forming substrate may be deposited on the surface of the carrier in the form of, for example, a sheet, foam, gel, or slurry. The solid aerosol-forming substrate may be deposited over the entire surface of the carrier, or alternatively, may be deposited in a pattern to provide a non-uniform flavor delivery during use.

[0088] The aerosol generating device may include a heater assembly. The heater assembly may be configured to heat an aerosol-forming substrate received within the cavity during use. A controller may be configured to control the heater assembly. The controller 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 at least partially received within the cavity.

[0089] The heater assembly may include a heating element. In use, power may be supplied to the heating element to heat it. Heat may then be transferred to the received aerosol-forming substrate, for example, by conduction through the device housing that forms the chamber.

[0090] The heating element may be a resistive heating element. The heating element may include 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, and composites made of ceramic and metallic materials. Such composites may include doped and undoped ceramics.

[0091] In another embodiment, the heater assembly may include one or more inductor coils and the heating element may include one or more susceptor elements.

[0092] One or more susceptor elements may be configured to be heatable by an alternating magnetic field generated by an inductor coil or coils. During use, power supplied to the inductor coil (e.g., by the apparatus's power supply) can cause the inductor coil to induce eddy currents in the susceptor elements. These eddy currents then cause the susceptor elements to generate heat. Power is supplied to the inductor coil 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 an aerosol-forming substrate is received in the chamber, heat generated by the susceptor elements is generated by heating the aerosol-forming substrate to a temperature sufficient to emanate an aerosol from the substrate. The susceptor elements may be formed of a material capable of absorbing electromagnetic energy and converting it to heat. By way of example and without limitation, the susceptor elements may be formed of a ferromagnetic material such as steel.

[0093] The aerosol generating device may include a power source that may be configured to supply an electrical current to the resistive heating element.

[0094] The heating element may comprise a substrate layer of flexible material. The substrate layer may comprise a thermally stable polymer, preferably a polyimide.

[0095] The heating element may be disposed on the substrate layer. The heating element may include a wire connection configured to connect to a controller of the aerosol generating device. The heating element may comprise a heating track disposed on the substrate layer. The heating track may comprise a thermally conductive material, preferably a metal such as stainless steel. The heating track may be electrically connected to the wire connection.

[0096] The heating element may take other forms, such as one or more metal grids, flexible printed circuit boards, molded circuit components (MIDs), ceramic heaters, flexible carbon fiber heaters, or may be formed using coating techniques such as plasma deposition onto a suitably shaped substrate.

[0097] As used herein, transparency to a particular wavelength of electromagnetic radiation, whether in a transparent portion or otherwise, means that at least 90%, preferably at least 95%, and even more preferably at least 99% of the electromagnetic radiation at that wavelength can pass through the first or second portion without being absorbed.

[0098] The present invention further relates to a sensing assembly for an aerosol-generating device for generating an aerosol from an aerosol-forming substrate. The aerosol-generating device may include a cavity for receiving the aerosol-forming substrate. The sensing assembly may include a multi-layer substrate. The multi-layer substrate may include a first outer layer defining a first side of the substrate. The multi-layer substrate may include a second outer layer defining a second side of the substrate. The sensing assembly may include an emitter configured to emit electromagnetic radiation into the cavity. The emitter may be provided on the first outer layer on a first portion of the substrate. The sensing assembly may include a sensor configured to measure at least one wavelength of the received electromagnetic radiation. The sensor may be provided on the first outer layer on a second portion of the substrate. The sensing assembly may include at least one heat-dissipating structure. The heat-dissipating structure may be selected from a metal backing layer provided 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 at least 5 millimeters beyond the first or second portion. The extended end portion may not include conductive tracks on its surface.

[0099] The sensing assembly may include any of the features described in relation to any one of the preceding aspects of the present disclosure.

[0100] The present invention further relates to an aerosol-generating system comprising an aerosol-generating device as described herein and an aerosol-generating article comprising an aerosol-forming substrate.

[0101] As used herein, the terms "proximal," "distal," "downstream," and "upstream" are used to describe the relative position of a component or portion of a component of an aerosol generating device with respect to the direction in which a user draws on the aerosol generating device during use.

[0102] As used herein, "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, for example 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 is inhalable directly through the user's mouth into the user's lungs. The aerosol-generating device may be a holder. The device may be an electrically heated smoking device. The aerosol-generating device may comprise a housing, an electrical circuit, a power source, a heating chamber, and a heating element.

[0103] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of emitting a volatile compound capable of forming an aerosol. For example, the aerosol-generating article may be a smoking article that generates an aerosol that can be inhaled directly through the user's mouth into the user's lungs. The aerosol-generating article may be disposable.

[0104] As used herein, the term "aerosol-forming substrate" relates to a substrate capable of emitting one or more volatile compounds capable of forming an aerosol. Such volatile compounds may be emitted by heating the aerosol-forming substrate. The aerosol-forming substrate may conveniently be part of an aerosol-generating article or a smoking article.

[0105] Below is provided a non-exhaustive list of non-limiting examples, any one or more of the features of these examples may be combined with any one or more features of any other example, embodiment, or aspect described herein. [Example]

[0106] Example 1: An aerosol generating device comprising a cavity for receiving an aerosol-forming substrate and a sensing assembly for detecting the aerosol-forming substrate in the cavity, the sensing assembly comprising: 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; an emitter configured to emit electromagnetic radiation into the cavity and provided on a first outer layer on the first portion of the substrate; a sensor provided on the first outer layer on the second portion of the substrate, the sensor configured to measure at least one wavelength of the received electromagnetic radiation; at least one heat dissipation structure, a metal backing layer provided on the surface of the second outer layer of the substrate; - an extended end portion of the base located 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 not including a conductive track on its surface.

[0107] Example 2: An aerosol generating device as described in Example 1, wherein the substrate comprises one or more printed circuit boards, preferably one or more flexible printed circuit boards.

[0108] Example 3: An aerosol generating device as described in Example E1 or Example 2, wherein the substrate comprises an intermediate layer disposed between the first outer layer and the second outer layer, and preferably the first outer layer and the second outer layer of the substrate are printed circuit boards.

[0109] Example 4: An aerosol generating device as described in Example 3, wherein the intermediate layer is a metal layer, preferably the intermediate layer comprises copper, more preferably the intermediate layer is a copper layer.

[0110] Example 5: An aerosol generating device as described in any one of Examples 1 to 4, comprising an extended end portion of the base, the extended end portion comprising a copper layer, preferably the copper layer being an intermediate layer disposed between the first outer layer and the second outer layer.

[0111] Example 6: An aerosol generating device as described in any one of Examples 1 to 5, comprising an extended end portion of the base located adjacent to the first portion or adjacent to the second portion, the extended end portion extending beyond said first portion or second portion by a distance of at least 10 millimeters, preferably at least 12 millimeters, more preferably at least 14 millimeters, more preferably between 14 millimeters and 17 millimeters.

[0112] Example 7: An aerosol generating device as described in any one of Examples 1 to 6, comprising both an extended end portion of the substrate and a metal backing layer, wherein the metal backing layer is not provided on the surface of the second outer layer of the substrate in the region of the extended end portion.

[0113] Example 8: An aerosol generating device according to any one of Examples 1 to 7, comprising a metal backing layer, wherein the metal backing layer is a steel layer, preferably a stainless steel layer, more preferably the steel is JIS SUS304.

[0114] Example 9: An aerosol generating device according to any one of Examples 1 to 8, comprising a metal backing layer, the metal backing layer being 0.1 to 0.5 millimeters thick, preferably 0.2 to 0.4 millimeters, more preferably 0.25 to 0.35 millimeters thick.

[0115] Example 10: An aerosol generating device as described in any one of claims 1 to 9, comprising a metal backing layer, the metal backing layer comprising first and second individual metal plates, the first metal plate preferably being provided on a first portion of the second outer layer of the substrate opposite the first portion of the first outer layer of the substrate, and the second metal plate being provided on a second portion of the second outer layer of the substrate opposite the second portion of the first outer layer of the substrate.

[0116] Example 11: An aerosol generating device as described in Example 10, wherein each of the first and second metal plates has a width of 0.2 mm to 0.6 mm, preferably 0.35 mm to 0.45 mm, and a length of 0.7 mm to 1.3 mm, preferably 0.95 mm to 1.05 mm.

[0117] Example 12: An aerosol generating device according to any one of Examples 1 to 11, wherein the first and second portions of the substrate are planar and non-coplanar, and preferably 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 about 80 degrees.

[0118] Example 13: An aerosol generating device according to any one of Examples 1 to 12, comprising an aerogel layer disposed between the substrate and the central axis of the cavity in the longitudinal direction, preferably the aerogel layer having a thickness of 0.1 millimeters to 0.3 millimeters.

[0119] Example 14: The aerosol generating device according to any one of Examples 1 to 13, wherein at least a portion of the substrate is flexible.

[0120] Example 15: An aerosol generating device as described in Example 14, wherein the substrate further comprises a third portion between the first portion and the second portion, at least the third portion being flexible so that the first portion is movable relative to the second portion, and preferably no metal backing layer is provided on the surface of the second outer layer of the third portion of the substrate.

[0121] Example 16: An aerosol generating device as described in Example 15, wherein the flexible portion is configured such that the emitter is movable relative to the sensor by bending the flexible portion.

[0122] Example 17: An aerosol generating device as described in Example 16, wherein the substrate is curved so that the emitter is adjacent to a different part of the cavity relative to the sensor and 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, even more preferably between 70 degrees and 90 degrees, and most preferably about 80 degrees.

[0123] Example 18: An aerosol generating device described in any one of Examples 1 to 17, comprising a shield 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 shield plate, preferably wherein the sensor is positioned between a first portion of the shield plate and the cavity, and the emitter is positioned between a second portion of the shield plate and the cavity.

[0124] Example 19: An aerosol generating device described in any one of Examples 1 to 18, wherein the temperature of the sensing assembly during operation of the device 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.

[0125] Example 20: An aerosol generating device described in any one of Examples 1 to 19, wherein the cavity is defined by a housing of the device, a first portion of the housing is transparent to at least some of the wavelengths of the electromagnetic radiation emitted by the emitter, and the emitter is configured to emit electromagnetic radiation into the cavity through the transparent portion.

[0126] Example 21: An aerosol generating device described in any one of Examples 1 to 20, wherein the sensing assembly further comprises amplification electronics directly connected to the sensor.

[0127] Example 22: An aerosol generating device as described in any one of claims 1 to 21, further comprising a controller configured to receive a signal from the sensor, the controller configured to determine material properties of the aerosol-forming substrate at least partially received in the cavity, or an aerosol-generating article including the aerosol-forming substrate, based on the measured intensity of the electromagnetic radiation received by the sensor.

[0128] Example 23: An aerosol-generating device as described in Example 22, wherein the material property determined by the controller comprises the wettability or water content of the aerosol-forming substrate.

[0129] Example 24: An aerosol-generating system comprising an aerosol-generating device according to any one of Examples 1 to 23 and an aerosol-generating article including an aerosol-forming substrate.

[0130] Features described with respect to one embodiment may be equally applied to other embodiments of the invention.

[0131] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief explanation of the drawings]

[0132] [Figure 1] Figure 1 shows an aerosol generation system. [Figure 2] Figures 2a) and b) show the sensing assembly. [Figure 3] FIG. 3 shows the sensing assembly. [Figure 4] Figures 4a) and b) show a multilayer substrate. [Figure 5] Figures 5a) and b) show a multilayer substrate.

[0133] 1 shows a cross-sectional view of an aerosol-generating system 10. The aerosol-generating system 10 also includes an aerosol-generating article 12. The aerosol-generating article 12 includes an aerosol-forming substrate 14 located at a distal portion thereof. The aerosol-generating system 10 further includes an aerosol-generating device 20. The aerosol-generating device 20 includes a cavity 22 for receiving the aerosol-forming substrate 14. The cavity 22 is defined within a housing 24 of the aerosol-generating device 20.

[0134] 1, the distal portion of the aerosol-generating article 12, including the aerosol-forming substrate 14, is inserted into the cavity 22. The aerosol-forming substrate 14 may be a solid tobacco-containing substrate. In particular, the aerosol-forming substrate 14 may be a collection of homogenized tobacco sheets.

[0135] 1, the aerosol-generating article 12 and cavity 22 are configured such that when the aerosol-generating article 12 is received within the cavity 22, the mouth end of the aerosol-generating article 12 protrudes from the cavity 22 and from the aerosol-generating device 16. This mouth end forms the mouthpiece 16 from which a user of the aerosol-generating device may draw smoke during use.

[0136] The aerosol-generating device 20 includes a heater assembly that includes a heating element 26. The heating element 26 surrounds the cavity 22 along with a portion of the cavity 22 in 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 portion of the housing 24 that defines the portion of the cavity 22 that receives the aerosol-forming substrate 14. The heating element 26 may be a resistive heating element.

[0137] The airflow channel 28 extends from an air inlet 30 of the aerosol-generating device 20. Upstream of the cavity 22, the airflow channel 28 is defined primarily by an airflow channel wall 32. Downstream of the airflow channel wall 32, the airflow channel 28 passes through an air inlet defined in a base 34 of the cavity 22. The airflow channel 28 then extends through the cavity 22. When the aerosol-generating article 12 is received within the cavity 22, the airflow channel 28 passes through the aerosol-generating article 12 and extends through the mouthpiece 16.

[0138] The aerosol generating device 20 further comprises a power supply 36 in the form of a rechargeable battery for powering the heating element 26, which is controllable by a controller 38. The power supply 36 is connected to the controller 38 and the heating element 26 via wires and connections not shown. The aerosol generating device 20 may comprise further elements not shown, such as a button for activating the aerosol generating device 20.

[0139] The aerosol-generating device 20 further comprises a sensing assembly 40 for detecting the aerosol-forming substrate 14 within the cavity 22 .

[0140] Figure 2a more clearly shows the sensing assembly 40. Figure 2a is a perspective view of the sensing assembly 40 with a portion of the aerosol generating device 20 cut away.

[0141] The sensing assembly 40 includes an emitter 42. The emitter 42 includes a plurality of LEDs, each configured to emit electromagnetic radiation of a different wavelength. The emitter 42, and in particular the plurality of LEDs of the emitter 42, are configured to emit electromagnetic radiation into the cavity 22. The emitter 42 is configured to emit electromagnetic radiation having a wavelength between 1350 and 1400 nanometers.

[0142] 1 , housing 24, which defines a portion of cavity 22, includes first transparent portion 23. Emitter 42 is separated from cavity 22 by first transparent portion 23 and is configured to emit electromagnetic radiation into cavity 22 through first transparent portion 23. Providing first transparent portion 23 protects emitter 42 from debris and dirt that may accumulate within cavity 22 after extended use of device 20, and allows for easy cleaning.

[0143] As shown in FIG. 2a, 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 emitted by the emitter 42 and then reflected or transmitted by the aerosol-generating article 12 toward the sensor 44. The sensor 44 includes a photodiode. The sensor 44 is configured to measure multiple wavelengths of the received electromagnetic radiation. In particular, the sensor 44 is configured to measure the intensity of multiple wavelengths of the received electromagnetic radiation. The sensor 44 is configured to receive electromagnetic radiation having a wavelength between 1350 and 1400 nanometers.

[0144] Cavity 22 includes a second transparent portion, not shown in the figures. Sensor 44 is separated from cavity 22 by the second transparent portion and is configured to receive electromagnetic radiation from cavity 22 through the second transparent portion.

[0145] The sensing assembly 40 further includes a multi-layer substrate 50 comprising 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 emitter 42 is provided on the first outer layer on a first portion 52 of the substrate 50. The sensor 44 is provided on the first outer layer on a second portion 54 of the substrate 50.

[0146] Both the first portion 52 and the second portion 54 of the substrate 50 are planar. The substrate 50 further comprises a flexible third portion 56. As shown most clearly in Figures 2a and 3, the third portion 56 is bent so that the angle between the first portion 52 and the second portion 54 is 100 degrees. Thus, the angle between the normal to the first portion 52 and the normal to the second portion 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 2b). This provides optimal optical performance.

[0147] The third portion 56 is opaque to the wavelengths of electromagnetic radiation 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 base 50 includes a further flexible portion that allows the base 50 to be folded into the shapes shown in Figures 2a and 3.

[0148] Figure 2b shows the angle between the aerosol-generating article 12, the emitter 42, and the sensor 44. Figure 2b is a cross-section of the aerosol-generating article 12, the emitter 42, and the sensor 44, separate from the rest of the device 20. The optimum angle between the central optical axis 42a of the emitter 42 and the central optical axis 44a of the sensor 44 is 80 degrees. The angle is represented by the numeral 43 in Figure 2b.

[0149] 3 shows another cutaway perspective view of a section of aerosol generation device 20 including sensing assembly 40 (but looking toward the cavity from approximately the opposite direction compared to FIG. 2a). FIG. 3 shows several components of sensing assembly 40 in an exploded view, namely, shield plate 60, substrate 50, and aerogel layer 86.

[0150] In the assembled configuration, these components are mounted on top of one another. Aerogel layer 86 is disposed between substrate 50 and longitudinal central axis 21 of cavity 22. Aerogel layer 86 has a thickness of approximately 0.2 millimeters.

[0151] The shield plate 60 is configured to block electromagnetic radiation and is disposed outside the cavity such that the sensor 44 is disposed between the cavity 22 and at least a portion of the shield plate 60. In the embodiment shown, both the sensor 44 and the emitter 42 are positioned between the shield plate 60 and the cavity 22. In this manner, electromagnetic radiation external to the cavity 22 and the sensing assembly 40 is prevented from reaching the emitter 42 and, more importantly, the sensor 44. This means that the amount of external electromagnetic radiation received by the sensor 44 is substantially reduced or eliminated, and therefore not detected as noise by the sensor 44.

[0152] The shield plate 60 is sufficiently rigid to be able to maintain and hold the first portion 52 of the substrate 50 relative to the second portion 54 such that the angle between the normal to the first portion 52 and the normal to the second portion 54 is 80 degrees.

[0153] The shield plate 60 may include a first clip 82 at a first end and a second clip 84 at a second end, the first end being at an end opposite the second end of the shield plate 60. The first and second clips 82, 84 are configured to connect the shield plate 60 to the base 50.

[0154] 1 , the sensing assembly 40 is positioned relatively close to the heating element 26. Therefore, when an electric current is passed through the heating element 26 and the heating element 26 is heated, heat is inevitably transferred from the heating element 26 to the sensing assembly 40 during use of the aerosol generating device 20. The emitter 42 and the sensor 44 may be damaged if they become overheated. The heat dissipation structure of the sensing assembly 40, which dissipates heat from the emitter 42 and the sensor 44, may reduce the risk of damage to the emitter 42 and the sensor 44, as will be described in more detail below.

[0155] 4a shows the base 50 lying flat in a top view, separate from the rest of the aerosol generating device 20. The base 50 of the sensing assembly 40 further comprises analog amplifier electronics 57 configured to amplify signals generated by the sensor 44. The amplifier electronics 57 is mounted to a fourth portion of the base 50. By providing the amplifier electronics 57 on the same printed circuit board (PCB) of the base 50 as the sensor 44, there can be a direct electrical connection between the amplifier electronics 57 and the sensor 44. This minimizes the number of electrical connections between the amplifier electronics 57 and the sensor 44, and therefore minimizes the amount of noise introduced into signals generated by the sensor 44 before those signals are amplified.

[0156] The base 50 further comprises a connector 58. The connector 58 is used to connect the base 50 to the remaining electronics of the aerosol generating device 20, particularly the controller 38 and power supply 36.

[0157] Base 50 further comprises an extended end portion 59 of base 50 located adjacent second portion 54. Extended end portion 59 extends approximately 16 millimeters beyond second portion 54 and does not include conductive tracks on its surface. Extended end portion 59 functions as a heat dissipation structure for dissipating heat from sensor 44 during use.

[0158] The flexible third portion 56 of the base 50 has already been described. The base 50 includes a further flexible portion that allows the base 50 to be folded into the shape shown in Figures 2a and 3.

[0159] FIG. 4b shows an embodiment in which the substrate 50 is separated from the rest of the aerosol generating device 20 and laid flat in a perspective view. The substrate 50 of FIG. 4b differs from the substrate 50 of FIG. 4a in that the substrate 50 of FIG. 4b further includes a metal backing layer 90 on the back surface, i.e., the second outer layer, of the substrate 50, as indicated by the arrow in FIG. 4b. The metal backing 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 approximately 0.4 mm and a length of approximately 1.0 mm. The first metal plate 92 is provided on the rear side of the first portion 52 of the substrate 50 facing the emitter 42. The second metal plate 94 is provided on the rear side of the second portion 54 of the substrate 50 opposite the sensor 44.

[0160] Metal backing layer 90 functions as a heat dissipation structure to dissipate heat from emitter 42 and sensor 44 during use. Additionally, metal backing layer 90 functions as a stiffener to provide mechanical stability to first and second portions 52 of substrate 50.

[0161] Figure 5a shows a top view of substrate 50 including second portion 54 and a portion of extended end portion 59. Second portion 54 includes a conductive track 503 on its surface. Extended end portion 59 does not include a conductive track on its surface. Extended end portion 59 extends beyond second portion 54 a distance of at least 5 millimeters, the distance being indicated by the double-headed arrow in Figure 5a.

[0162] Figure 5b shows in cross section a subsection of substrate 50 including second portion 54 and a portion of extended end portion 59 and metal backing layer 90. Metal backing layer 90 has a thickness of approximately 0.3 millimeters.

[0163] 5b shows that the multi-layer substrate 50 includes a first outer layer 502 that defines a 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 a second side of the substrate 50. The second outer layer 504 of the substrate 50 is a PCB.

[0164] The substrate 50 further comprises 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.

[0165] The extended end portion 59 of the substrate 50 also 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.

[0166] During use of the aerosol-generating device 20, the aerosol-generating article 12 is received within the cavity 22, as shown in FIG. 1 . The sensing assembly 40, in conjunction with the controller 38, can detect the presence of the aerosol-generating article 12. The emitter 42 of the sensing assembly 40 emits electromagnetic radiation at multiple wavelengths. This radiation is then reflected and / or transmitted by the aerosol-generating article 12. Because 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 significant amount of reflected and / or transmitted electromagnetic radiation is received by the sensor 44. The sensor 44 measures the intensity of the various wavelengths of the received electromagnetic radiation. In doing so, the sensor 44 generates electrical signals. These electrical signals are sent directly to the amplification electronics for amplification before being received by the controller 38. The controller 38 is configured to perform spectral analysis on the measurements of the intensity of the electromagnetic radiation at different wavelengths. This involves comparing the intensities of different wavelengths of electromagnetic radiation to a known distribution of intensities emitted by emitter 42. Based on the spectral analysis, controller 38 is configured to determine the presence of aerosol-generating article 12.

[0167] The controller 38 is also configured to determine the type of 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 of different chemical compositions can be received in the cavity 22. Because the aerosol-generating articles 12 and the aerosol-forming substrates have different chemical and / or material properties, different aerosol-generating articles 12 reflect or transmit the wavelengths of electromagnetic radiation emitted by the emitter 42 to different degrees. This means that the spectrum of electromagnetic radiation received by the sensor 44 will be different for different aerosol-generating articles 12. The spectrum of a particular type of aerosol-generating article 12 is predictable. Therefore, based on the spectral analysis, the controller 38 can determine the type of aerosol-generating article 12 received in the cavity 22.

[0168] The controller 38 is configured to control the heating element 26 according to an appropriate heating profile for the determined type of aerosol-generating article 12 .

[0169] Based on this spectral analysis, the controller 38 is also configured to determine a material property of the aerosol-generating article 12 received within the cavity 22. In particular, the controller 38 is configured to determine a material property of the aerosol-forming substrate 14 of the aerosol-generating article 12. The material property determined by the controller 38 is the wettability or water content of the aerosol-forming substrate.

[0170] The controller 38 is configured to determine a value associated with the water content of the aerosol-forming substrate 14 received within the cavity 22 based on the measured intensity of the electromagnetic radiation received by the sensor 44. As described above, the emitter 42 and the sensor 44 are configured to emit and receive, respectively, wavelengths of electromagnetic radiation having wavelengths between 1350 nanometers and 1400 nanometers. Water is particularly effective at absorbing electromagnetic radiation in this range. Therefore, the radiation intensity received by the sensor 44 is highly dependent on the water content of the aerosol-forming substrate 14, and the controller 38 can determine a value associated with the water content of the aerosol-forming substrate 14 based on a spectral analysis of the electromagnetic radiation received by the sensor 44.

Claims

1. 1. An aerosol generating device comprising: a cavity for receiving an aerosol-forming substrate; and a sensing assembly for detecting the aerosol-forming substrate in the cavity, the sensing assembly comprising: 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; an emitter configured to emit electromagnetic radiation into the cavity and provided on the first outer layer on a first portion of the substrate; a sensor provided on the first outer layer on the second portion of the substrate, the sensor configured to measure at least one wavelength of received electromagnetic radiation; at least one heat dissipation structure, a metal backing layer provided on the surface of the second outer layer of the substrate; - an extended end portion of the base located 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 not including a conductive track on its surface.

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

3. 3. An aerosol generating device as described in claim 1 or claim 2, wherein the substrate has an intermediate layer disposed between the first outer layer and the second outer layer, and preferably the first and second outer layers of the substrate are printed circuit boards.

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

5. 2. The aerosol generating device of claim 1, comprising an extended end portion of the base, the extended end portion comprising a copper layer, preferably the copper layer being an intermediate layer disposed between the first outer layer and the second outer layer.

6. 2. The aerosol generating device of claim 1, comprising an extended end portion of the base located adjacent to the first portion or adjacent to the second portion, the extended end portion extending beyond the first or second portion by a distance of at least 10 millimeters, preferably at least 12 millimeters, more preferably at least 14 millimeters, and more preferably between 14 millimeters and 17 millimeters.

7. 2. The aerosol generating device of claim 1, comprising both the extended end portion of the substrate and the metal backing layer, wherein the metal backing layer is not provided on the surface of the second outer layer of the substrate in the region of the extended end portion.

8. 2. The aerosol generating device according to claim 1, comprising a metal backing layer, the metal backing layer being a steel layer, preferably a stainless steel layer, more preferably the steel being JIS SUS304.

9. 2. The aerosol generating device of claim 1, comprising a metal backing layer, the metal backing layer having a thickness of 0.1 to 0.5 mm, preferably 0.2 to 0.4 mm, more preferably 0.25 to 0.35 mm.

10. 2. The aerosol generating device of claim 1, further comprising a metal backing layer, the metal backing layer including first and second individual metal plates, the first metal plate being provided on the first portion of the second outer layer of the substrate opposite the first portion of the first outer layer of the substrate, and the second metal plate being preferably provided on the second portion of the second outer layer of the substrate opposite the second portion of the first outer layer of the substrate.

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

12. 2. The aerosol generating device of claim 1, wherein the first and second portions of the substrate are planar and non-coplanar, and preferably the angle between the normal to the planar first portion of the substrate and the normal to the planar second portion of the substrate is between 60 and 100 degrees, preferably between 70 and 90 degrees, and more preferably about 80 degrees.

13. 2. The aerosol generating device of claim 1, further comprising an aerogel layer disposed between the substrate and the longitudinal central axis of the cavity, wherein the aerogel layer preferably has a thickness of 0.1 millimeter to 0.3 millimeter.

14. 10. The aerosol generating device of claim 1, wherein at least a portion of the substrate is flexible.

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

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

17. 17. The aerosol generating device of claim 16, wherein the substrate is curved so that the emitter is adjacent to a different part of the cavity relative to the sensor and 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, even more preferably between 70 degrees and 90 degrees, and most preferably about 80 degrees.

18. 2. The aerosol generating device of claim 1, comprising a shield plate configured to block electromagnetic radiation and positioned outside the cavity so that the sensor is disposed between the longitudinal central axis of the cavity and at least a portion of the shield plate, preferably the sensor is positioned between a first portion of the shield plate and the cavity, and the emitter is positioned between a second portion of the shield plate and the cavity.

19. 2. The aerosol generating device of claim 1, wherein 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 during operation of the device.

20. 2. The aerosol generating device of claim 1, wherein the cavity is defined by the housing of the device, a first portion of the housing is transparent to at least a portion of the wavelengths of the electromagnetic radiation emitted by the emitter, and the emitter is configured to emit the electromagnetic radiation into the cavity through the transparent portion.

21. 10. The aerosol generating device of claim 1, wherein the sensing assembly further comprises amplification electronics directly connected to the sensor.

22. 2. The aerosol generating device of claim 1, further comprising a controller configured to receive a signal from the sensor, the controller configured to determine material properties of the aerosol-forming substrate at least partially received within the cavity, or an aerosol-generating article including the aerosol-forming substrate, based on the measured intensity of the electromagnetic radiation received by the sensor.

23. 23. The aerosol generating device of claim 22, wherein the material properties determined by the controller include the wettability or water content of the aerosol-forming substrate.

24. An aerosol generating system comprising the aerosol generating device of claim 1 and an aerosol-generating article including the aerosol-forming substrate.

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