Aerosol generation device equipped with a control system and a corresponding control method

Abstract

The present invention relates to an aerosol generation device (1) configured to receive a consumable article (100), - at least one optical element (20) at least partially defining the boundary of a heating cavity (200), - at least one sensing system (10) comprising an electromagnetic radiation detection system (14) configured to measure the intensity of electromagnetic radiation that has passed through and / or been reflected by the optical element (20), - a control system (50) configured to monitor an optical parameter representative of the level of contamination of the heating cavity (200) based at least on the aforementioned measured intensity and to trigger an alarm system (60) according to the aforementioned parameter. The present invention also relates to an aerosol generation system comprising the aerosol generation device (1) and an aerosol generation article (100).

Description

Technical Field

[0001] The present invention relates to the field of tobacco, and in particular to reconstituted tobacco and aerosol-generating articles. The present invention further relates to an electronic smoking device, and in particular to an electrically heated aerosol-generating system.

Background Art

[0002] In recent years, the popularity of electronic cigarettes using aerosol-generating consumable articles has been increasing. There are mainly two types, namely, liquid vaporizers and heated tobacco inhalation devices. Heated tobacco inhalation devices are called "heat-not-burn" systems (HNB). The HNB system provides a more authentic tobacco flavor compared to electronic cigarettes that heat a liquid filling containing an aerosol-forming agent, flavoring, and often nicotine, to provide an inhalable aerosol. The operating principle of the HNB system is to heat a tobacco material containing an aerosol-forming substance (such as glycerin and / or propylene glycol), which evaporates during heating and creates a vapor that extracts nicotine and flavor components from the tobacco material. The tobacco substance is heated to 200 - 400°C, which is lower than the normal combustion temperature of conventional cigarettes. The inhalation device is usually a handheld heater and is configured to receive a rod-shaped consumable article.

[0003] When an aerosol-generating substrate such as a tobacco substrate is heated by a heating element in the heating cavity of an aerosol-generating device, volatile compounds are released. Such volatile compounds and aerosols deposit on the surface of the aerosol-generating device. These substances deposit particularly on the side walls or bottom of the heating cavity. Furthermore, these contaminants may accumulate and / or may be partially removed in some cases by the friction of the inserted aerosol-generating article. Also, particles of the aerosol-generating article, such as particles from the packaging of the aerosol-generating article or particles of the substrate, may deposit on the walls of the heater cavity. Therefore, generally, after repeated use of the aerosol-generating article, particles, a layer of contaminants, and dust accumulate inside the heating cavity of the device.

[0004] Residual contaminant layers and dust particles pose problems for the use of aerosol generating devices, presenting problems in several aspects. First, due to the accumulation of residue layers and dust on the walls of the heating cavity, the required airflow of the device may be reduced or blocked. The level of contamination can also affect the perception of the optimal aroma of the aerosol. In fact, the contaminant layer and particles may give the user an unpleasant or bitter aroma. Also, depending on the aspect and location where the contaminant layer or particles accumulate, the heating element may be damaged. Although cleaning tools may be used to clean the heating cavity, damage may occur if the cleaning operation is too frequent or too infrequent. There are also several methods to partially reduce contaminants, such as using a pyrolysis method to heat the heating element to a temperature high enough to burn the residue or deposit, but this is not always effective.

[0005] So far, for example, it has been common to propose a cleaning frequency by a cleaning tool, which relied only on statistical knowledge about the average contamination level of the heating cavity that is a function of the usage frequency of aerosol articles in the device.

[0006] Therefore, it is necessary to provide a method for directly measuring the contamination level of the heating cavity so that a warning signal can be provided to the aerosol generating system and the user once the contamination threshold is reached. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0007] The inventors of the present invention have found a solution to the above problems by providing an aerosol generating device having a optoelectronic system that triggers a cleaning warning for an oven, also defined as a heating cavity, of the aerosol generating device. More specifically, the device of the present invention makes it possible to provide an optical solution for detecting the contamination of the cavity and identifying information regarding the contamination by detecting and analyzing the optical properties of contaminants deposited on the surface of the heating cavity.

[0008] Accordingly, in a first aspect, the present invention relates to an aerosol generating device comprising a heater body and a longitudinal heating cavity, the longitudinal heating cavity having an opening at one insertion end and being adapted to receive at least a portion of an aerosol generating article inserted through the opening.

[0009] This aerosol generating device - at least one optical element disposed on or in the heater body and at least partially defining a boundary of the cavity; - at least one sensing system including an electromagnetic radiation detection system configured to measure an intensity of electromagnetic radiation that has passed through and / or been reflected by the optical element and including at least one detector; - a control system configured to monitor an optical parameter representative of a level of contamination of the heating cavity based on at least the measured intensity and trigger an alarm system according to the parameter.

[0010] The invented device makes it possible to provide a system and method for measuring the level of soiling of the oven without relying on statistical estimates. Using an optical detection system makes it possible to provide information regarding various possible optical characteristics of the deposited dirt or dirt layer. In fact, the deposited dirt may change, for example, at least one of transmission, scattering, polarization, and reflection of electromagnetic waves.

[0011] In an advantageous embodiment, at least one of the optical elements includes a window that is at least partially transmissive to electromagnetic radiation. Incorporating the window into the wall of the heater can be easily achieved without significantly increasing the cost of the aerosol generating device. The window may be a small-sized element.

[0012] The heater preferably includes a heater body and a heating wire or electrode surrounding the outer surface of the heater body. In some variations, the heater body itself may generate heat, for example, by embedded wires or electrodes. The heater body may be heated without contact by a remote heat source, such as an infrared source. The heater body is preferably tubular, but the cross-section defined perpendicular to the longitudinal axis does not necessarily have to be circular. The tubular heater body may have, for example, a hexagonal cross-section and may provide flat sides that are easy to incorporate optical elements.

[0013] In an advantageous example, the window is at least partially made of glass, epoxy resin, or sapphire. Using a hard material such as glass or sapphire enables it to withstand very high temperatures, i.e., temperatures higher than 400°C. Some epoxy resins can also withstand high temperatures such as 250°C. Using a transparent epoxy has the advantage that it can be cast as a window within the aperture of the heating cavity.

[0014] In one embodiment, at least one of the optical elements is disposed on the insertion end side of the cavity. This position is currently the most appropriate position for the device in the state of the art.

[0015] In one embodiment, the aerosol generating device includes a plurality of sensing systems provided along the longitudinal direction of the cavity.

[0016] In some embodiments, at least one of the sensing systems further includes an electromagnetic radiation emission system configured to irradiate the optical element.

[0017] Advantageously, at least one electromagnetic radiation emitter and at least one electromagnetic radiation detector are arranged on the same side as at least one optical element, along the lateral directions (X, Y) of the cavity.

[0018] In some implementation variants, at least one electromagnetic radiation emitter and at least one electromagnetic radiation detection system are arranged on opposite sides of at least one optical element, along the lateral directions (X, Y) of the cavity.

[0019] In some embodiments, an aerosol generation device further includes a reference intensity detection system configured to measure a reference intensity of electromagnetic radiation emitted by at least one electromagnetic radiation emitter and including at least one reference detector.

[0020] In some embodiments, an aerosol generation device further includes a reference intensity detection system configured to measure a reference intensity of electromagnetic radiation outside the longitudinal cavity and preferably in the vicinity of the optical element, and including at least one reference detector, and the control system monitors a ratio of the reference intensity to a measured intensity of electromagnetic radiation that has passed through and / or been reflected by at least one optical element, and is configured to trigger an alarm system according to the ratio.

[0021] In some variants, the aerosol generation device includes a beam splitter configured to reflect a part of the electromagnetic radiation emitted by the electromagnetic radiation emission system towards the reference intensity detection system.

[0022] In some examples, the electromagnetic radiation emission system includes a semiconductor emitter that emits at a wavelength included between 300 nm and 10 μm, preferably between 300 nm and 5 μm.

[0023] In some embodiments, at least one electromagnetic radiation detector is configured to measure the intensity of infrared light emitted by a heating element disposed around or inside the cavity, passed through and / or reflected by the optical element.

[0024] The present invention also relates to an aerosol generation system comprising the aerosol generation device described above and an aerosol generation article at least partially inserted into the cavity of the aerosol generation device, wherein at least a part of the aerosol generation article faces at least one optical element.

[0025] The present invention is also achieved by a method for controlling the aerosol generation device described above. The method includes at least the following steps, namely, a) measuring the intensity of electromagnetic radiation passed through and / or detected by at least one optical element; b) monitoring a parameter representing the level of contamination of the heating cavity based at least on the measured intensity; c) triggering an alarm system according to the parameter.

[0026] In one embodiment, the parameter monitored in step b represents the level of dirt deposited on the surface of the heater body surrounding the cavity.

[0027] In some variations, the method further includes irradiating at least one optical element with electromagnetic radiation. Preferably, the radiation is emitted by an electromagnetic radiation emission system.

[0028] The method may further include determining a reference intensity of the emitted electromagnetic radiation, and in steps b) and c), the parameter is the ratio between the reference intensity and the measured intensity of the electromagnetic radiation passed through and / or reflected by at least one optical element. BRIEF DESCRIPTION OF THE DRAWINGS

[0029]

Figure 1

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Figure 11

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Figure 18

DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be described with respect to specific embodiments with reference to the accompanying drawings, but the present invention is not limited thereto. The drawings to be described are only schematic and non-limiting. In the drawings, the sizes of some elements may be exaggerated for illustrative purposes and may not be drawn to scale. The dimensions and relative dimensions do not correspond to the actual reduction when the present invention is implemented.

[0031] The present invention will be described in the following examples related to aerosol-generating consumable articles containing a tobacco-containing charge of aerosol-generating material. However, the scope of application of the present invention should not be construed as being limited to tobacco-based consumable articles, but includes any aerosol-generating consumable articles such as smoking articles, heat-not-burn articles, e-liquid cartridges, and atomizers, which are provided with an aerosol-generating substrate capable of generating an inhalable aerosol when heated. The aerosol-generating consumable article according to the present invention may or may not have a symmetry axis, and may have any form or shape such as an elongated cylindrical shape, a spherical shape, or the form of a beam.

[0032] In a first aspect, the present invention is realized by an aerosol-generating device 1. The present invention is further realized by an aerosol-generating system 2 comprising the aerosol-generating device 1 and an aerosol-generating article 100 inserted into the aerosol-generating device 1.

[0033] As used herein, the term "aerosol-generating material" refers to a material capable of releasing a volatile compound that can form an aerosol when heated. The aerosol generated from the aerosol-generating material may be visible or invisible, and may include vapor (e.g., fine particles of a gaseous substance that is usually liquid or solid at room temperature), as well as gas and droplets of condensed vapor.

[0034] The term "package" is broadly defined as any structure or layer that protects and contains the filling of the aerosol-generating material and enables handling of that material. The package has an inner surface that may be in contact with the aerosol-generating material and an outer surface that is remote from the aerosol-generating material. The package may preferably contain a cellulose-based material such as paper, but may also be made of a biodegradable polymer, or of glass or ceramic. The package may be a porous material, may have a smooth or rough outer surface 5, and may be a flexible or rigid material. The package may constitute an optically impermeable or partially permeable optical layer. In the case of paper, the package forms a highly scattering layer and, due to the fact that it is usually very thin, i.e. less than 100 μm, is partially permeable in the visible light, infrared light, terahertz radiation range and may also be partially permeable in the UV. The package may also be provided with an aperture.

[0035] The term "heater" is a heating system for heating a substrate and includes a cavity 200, also defined as a heating cavity or oven, for introducing at least a portion of the article 100.

[0036] In a first aspect, the present invention relates to an aerosol-generating device 1 comprising a longitudinal heating cavity 200 having an opening 201 at one insertion end 210 and adapted to receive at least a portion of an aerosol-generating article 100 inserted through the opening 201.

[0037] In an advantageous embodiment, the heating cavity is defined by a tubular heating body. An embodiment of such a heating body is shown in FIG. 18. In some embodiments, the heating body is made of metal. In some variants, the heating body is an electrode or a heating wire, which is arranged outside the heater body and is heated by an electrode or a heating wire in thermal contact with the heating body. In some variants, the heating element may be incorporated into the heating body. In some embodiments, the heating body may be a tubular mechanism of a heating element such as a heating wire or a heating blade. The heating element may be embedded in a protective layer such as an epoxy layer.

[0038] The aerosol generating device 1 comprises - at least one optical element 20, 22, 23, 24, 25, 26, 27, 28 that at least partially defines the boundary of the cavity 200, and - at least one sensing system 10 including an electromagnetic radiation detection system 14 configured to measure the intensity of electromagnetic radiation that has passed through and / or been reflected by the optical elements 20, 22, 23, 24, 25, 26, 27, 28.

[0039] The device 1 has a front side 300 which is the side including the insertion opening 201 of the heating cavity 200. It is understood that the at least one sensing system 10 may be arranged at any position with respect to the cavity 200, for example at or in the vicinity of the insertion opening 201 of the device 1 as shown in FIG. 15, or on the side surface of the device 1 and the cavity 200 as shown in FIGS. 16 and 17. In some variants, the first optical detection system may be arranged in the vicinity of the opening 201 of the device 1. In some variants, at least a second detection system may be arranged in the longitudinal direction or at the bottom of the cavity 200, this bottom being on the side opposite to the opening 201.

[0040] The electromagnetic radiation detection system 14 includes at least one detector 114, which is also defined as a contamination detector. As will be further described, the electromagnetic radiation detection system 14 may include at least one reference detector 114b. The electromagnetic radiation detection system 14 includes, for example, an electronic circuit that converts the current provided by the detector 114 into a voltage signal. The electromagnetic radiation detection system 14 may be provided with electrical processing means for handling its signals.

[0041] It is understood that all embodiments disclosed herein may be combined with each other as long as they are technically possible.

[0042] The aerosol generation device 1 also includes a control system 50 configured to monitor an optical parameter representing the level of contamination of the heating cavity 200 based at least on the measured intensity and trigger an alarm system according to the parameter.

[0043] The present invention makes it possible to provide an aerosol generation device 1, an aerosol generation system, and a method for measuring the level of oven contamination without relying on statistical estimation. Using an optical detection system makes it possible to provide information on various possible optical characteristics of the dirt or dirt layer deposited on the heating body. In fact, the deposited dirt may change, for example, at least one of the transmission, scattering, polarization, and reflection of electromagnetic waves. In the case of a tubular heater body, the dirt or dirt layer may be deposited on at least a part of the inner surface of the heater body. The dirt or dirt layer may also be present in the heating cavity 200 and may be in partial contact with and / or adhered to the heater body. For example, a thin tobacco residue or filament may be adhered to the heater body.

[0044] For example, in the advantageous embodiment shown in FIG. 1, at least one optical element is a window 20 that is at least partially transmissive to electromagnetic radiation, typically but not limited to visible light or infrared radiation. The window 20 does not necessarily have to be a flat plate and may comprise at least one curved surface. Incorporating the window 20 into the wall of the heater can be easily achieved without significantly increasing the cost of the aerosol generating device. The window may be a small-sized element, for example, with a maximum width of 1 mm and a thickness of less than 0.5 mm. The window 20 may, for example, close an aperture provided in the wall of the heater. The window may comprise two or more window elements, which may be different window elements.

[0045] In an advantageous example, the window 20 is at least partially made of glass, epoxy resin, or sapphire. Using a hard material such as glass or sapphire enables it to withstand very high temperatures, i.e., temperatures higher than 400°C. Some epoxy resins can also withstand high temperatures such as 250°C. Using a transparent epoxy has the advantage that it can be cast as the window 20 within the aperture of the heating cavity 200.

[0046] In one embodiment, at least one of the optical elements 20, 22, 23, 24, 25, 26, 27, 28 is arranged on the side of the insertion end 210 of the cavity 200. This position is currently the most suitable position for the device 1 in the current state of implementation.

[0047] In one embodiment shown in FIG. 5, the aerosol generating device 1 includes a plurality of sensing systems 10, 10’, 10’’ provided along the longitudinal direction Z of the cavity 200.

[0048] In some embodiments, at least one sensing system 10, 10', 10'' further includes an electromagnetic radiation emitting system 12, 12', 12'' configured to irradiate optical elements 20, 22, 23, 24, 25, 26, 27, 28, which is also referred to herein as an electromagnetic radiation source. The electromagnetic radiation emitting systems 12, 12', 12'' may include a single emitter, or at least two emitters 112, 112' as shown in FIG. 2. The electromagnetic radiation emitting systems 12, 12', 12'' include at least one electronic circuit for powering the emitters 112, 112', 112''.

[0049] In some examples, the electromagnetic radiation emitting systems 12, 12', 12'' can include any radiation source that supplies electromagnetic radiation 120. The electromagnetic radiation 120 may be within the range of UV (ultraviolet), visible light, or infrared (IR) or terahertz radiation.

[0050] In some implementations, the electromagnetic radiation emitting systems 12, 12', 12'' may include emitters 112, 112', 112'' that emit at wavelengths included between 300 nm and 10 μm, preferably between 300 nm and 5 μm, such as, for example, semiconductor emitters. The electromagnetic radiation emitting system 12 may include, for example, a semiconductor laser or an LED that emits visible light or infrared light.

[0051] However, the electromagnetic radiation 120 does not necessarily have to be provided by a power-driven electromagnetic radiation source. The electromagnetic radiation emitting system 12 may be, for example, a surface portion of a heater, as shown in FIG. 18, or any high-temperature portion of an aerosol generating device 1 that provides infrared light radiation and / or, or a consumable article 100.

[0052] In some embodiments, as shown in FIG. 6, when illuminated by the electromagnetic radiation emitting system 12, the illuminated area of the surface of the aerosol-generating article 100 emits electromagnetic light due to a reflection effect and / or a scattering effect. Such re-emitted radiation may be provided by the surface of the aerosol-generating article and / or by a layer of contaminants or dust particles accumulated on the inner surface of the heater cavity 200. At least a portion 140 of the re-emitted radiation is directed towards the detector 114 of the detection system. The article 100 does not necessarily need to be introduced into the cavity 200 to measure the level of contamination. In fact, the contaminants affect the intensity of the detected electromagnetic radiation 140 resulting from the interaction of the incident radiation 120 with the contaminant layer or contaminant particles. Introducing the article 100 into the heater cavity 200 may increase the detected intensity because the surface of the aerosol-generating article typically acts as a highly scattering surface that partially reflects. By using terahertz frequencies, the electromagnetic radiation may penetrate the entire diameter of the aerosol-generating article. This means that even when the aerosol-generating article 100 is present within the heater cavity 200, configurations such as those shown in FIGS. 2, 4, and 5 can be used.

[0053] FIG. 6 shows an aerosol-generating system including an aerosol-generating device 1 and an aerosol-generating article 100. The wrapper of the aerosol-generating article 100 is a very light-scattering layer that can redirect the light emitted from the emitter towards the detector, and thus can provide information regarding the level of contamination of the window separating the emitter and the detector from the cavity. In some variations, shown in FIG. 17, the detector 114 may be disposed in a cavity 200 without a window. In that case, the contamination occurs directly on the surface of the detector. The electromagnetic radiation detection system 14 may include a single detector 114 or an array of detectors, or may comprise a small vision system. The detection system 14 may also include a color filter or a small spectrometer.

[0054] Advantageously, the electromagnetic radiation emission system 12 and the electromagnetic radiation detection system 14 are arranged on the same side as at least one optical element, along the lateral direction (X) of the cavity. This is shown in FIGS. 1, 3, 6, 7-12.

[0055] In some alternative embodiments, as shown in FIGS. 2, 4, and 5, the electromagnetic radiation emission system 12 and the electromagnetic radiation detection system 14 are arranged on opposite sides of at least one of the optical elements 20, 22, 23, 24, 25, 26, 27, 28, along the lateral direction X of the cavity. Such an arrangement as shown in FIGS. 2, 4, and 5 enables the provision of light beams 122, 122', 122'' across the cavity 200, and makes it possible to provide a method for detecting not only the accumulated contaminant layer but also dust or substrate particles within the space of the cavity 200.

[0056] In some advantageous embodiments, as shown in FIGS. 3 and 4, the aerosol generating device 1 further includes a reference intensity detection system configured to measure the reference intensity of the electromagnetic radiation emitted by the electromagnetic radiation emission system 12. In such a system, the control system 50 monitors the ratio between the reference intensity and the measured intensity of the electromagnetic radiation that has passed through or been reflected by at least one of the optical elements 20, 22, 23, 24, 25, 26, 27, 28, and is configured to trigger an alarm system according to the ratio.

[0057] Providing a reference intensity makes it possible to improve the reliability of the sensing system 10, because detection can be performed regardless of, for example, the aging degradation of the detector or the fluctuations in the intensity of the electromagnetic radiation sources 12, 12', 12'' that are emitting. For example, when the infrared radiation provided by the heater itself is used, the detection system can be calibrated, and the detection system may deliver a trigger signal that is independent of the intensity of the emitted radiation 120, and thus independent of the temperature of the heater.

[0058] In one embodiment shown in FIG. 18, the heater body 222 of the heater may be in thermal contact with a heat retaining element 224 having a different heat generation coefficient, such as a ceramic ring 224. Such a ring may provide infrared light IR into the cavity. This infrared light IR may be redirected by the package of the inserted article 100.

[0059] In another example of a system including an intensity criterion, for example using an LED emitter 12, a signal regarding the electrical drive of the LED may be provided such that the detection system 14 detects the same light intensity as measured before being contaminated. In order to achieve the same intensity as detected before being contaminated, an electrical signal directly related to the contamination level of the heating cavity 200 can be provided to the alarm system 60 by having to increase the intensity of the emitted light 120 and thus the drive current of the LED.

[0060] In an example of a sensing system 10 including an intensity criterion subsystem shown in FIG. 3, the aerosol generating device 1 comprises an electromagnetic wave beam splitter 130 configured to direct a part of the electromagnetic radiation 120 emitted by the electromagnetic radiation emitting system 112 towards the reference detector 142.

[0061] Here, some variations are further disclosed that may be adapted to any of the embodiments described herein.

[0062] For example, some means may be provided to increase the intensity level of the re-emitted light 140 that can be detected. For example, the package of the aerosol generating article may contain a substance that enhances reflectivity. For example, a fluorescent material may be incorporated on or in at least a part of the package to provide an effect of fluorescent or phosphorescent light. Also, in an advantageous embodiment shown in FIG. 6, the aerosol generating article 100 may include at least one reflecting element 110 on one of its surfaces that enhances the intensity of the light reflected from the surface of the article.

[0063] The reflective element 110 disposed on the article 100 may consist of, or may include at least one of the following: - A reflective element, optionally a reflective layer. The reflective layer may be a coating or, for example, a reflective element fixed to the package by an adhesive. - A diffractive element - An element including a metasurface - A holographic element - An element with high polarization sensitivity.

[0064] The reflector 110 of electromagnetic radiation disposed on the surface of the package may be realized by physical or chemical means on the surface such as the package of the aerosol generating article 100. The reflective element 110 may be disposed on a part of the circumference of the article 100 or, as shown in FIG. 6, may be disposed on the entire circumference. The reflector element 110 disposed on the article 100 may be a reflector with high polarization sensitivity.

[0065] The reflective element 110 disposed on the aerosol generating article of the present invention may be configured to provide a predetermined direct reflection effect such as providing a plurality of light beams having different spectra and / or different reflection angles when illuminated by a light beam provided by a light source. The reflected light beam may be a diffracted light beam projected at any diffraction order. The reflector element 110 may provide a reflected light beam 140 having a wide aperture so as to be able to inspect a wider contamination area. This may be improved by using a lens as shown in the variant of FIG. 11.

[0066] In general, it is understood that the optical sensing system 10 may include, but is not limited to, the following: - Refractive elements, such as single or compound lenses, prisms, beam splitters, Fresnel lenses - Reflective elements, such as plane or concave mirrors - Diffractive elements, such as diffractive lenses realized on a transparent substrate -An electrically addressable element, such as a MEMS device, for example a MEMS shutter or a MEMS micromirror, or a combination of such elements.

[0067] FIG. 7 shows a variant of an optical detection system arranged within the cavity of a heater. In such a variant, the optical element is a reflective surface or mirror 23. Contaminants accumulated on the reflective surface reduce the reflectivity of the reflective surface and can thus be measured.

[0068] In another example shown in FIG. 8, the sensing system 10 comprises at least a microlens array. The use of a microlens array may enhance the detection sensitivity due to the focusing effect of each element of the microlens array. The microlens array may be arranged relative to the detector array in such a configuration that each microlens faces a certain detector of the detector array.

[0069] FIG. 9 shows another possible optical detection system arranged within the cavity 200 of a heater, which system comprises a diffuser including a structure that scatters electromagnetic waves. The use of a diffuser enables the smoothing of the influence of intensity variations caused by the wider contaminated surface.

[0070] FIG. 10 shows an example of a simple optical detection system arranged within the cavity of a heater that relies on a detector provided with a coating 28 as the optical element. In some variants, the proception window of the detector may be used as the optical element and the contamination effect has to be determined from this element.

[0071] FIG. 11 shows an optical detection system disposed within a cavity of a heater, the system including a detector and a lens disposed between the detector and the cavity of the heater. Providing lens 27 as an optical element enables focusing the re-emitted radiation onto a small detector that may be disposed remotely from the heater. Further, using lens 27 as an optical window enables detecting intensity fluctuations due to contaminants that are remote from the walls of the heater, such as contaminants due to dust or substrate particles floating within the heating cavity 200.

[0072] FIG. 12 shows an advantageous variant of a system including an optical trap configured to enhance the absorption effect by a contaminant layer or contaminant particles accumulated within the optical trap. An optical element in the form of an optical trap 28, as shown in the example of FIG. 12, may significantly amplify the effect of intensity fluctuations due to contamination. In a sense, such an optical trap 28 behaves like a waveguide due to multiple reflections of the radiation 140 directed towards the detector 14. As shown in FIG. 12, a detector in such a configuration may be disposed at the bottom of the cavity of the optical trap. In some variants, one or more detectors may also be disposed on the sidewalls of such an optical trap 28.

[0073] FIGS. 13 and 14 show examples of optical detection systems including at least one optical fiber. Using a waveguide such as an optical fiber or a planar waveguide enables, for example, disposing the emission system 12 and / or the detection system 14 remotely from a hot surface. Further, using an optical fiber with a small emission core and / or collection core enables providing a system with high sensitivity for detecting contamination levels.

[0074] FIG. 13 shows an example of an emission fiber 1120 having an emission edge 1120' and a collection fiber 1140 having a collection edge 1140'. Due to contamination of the heater cavity, the transmission intensity of the light beam 120 across the space V between the emission edge 1120' and the collection edge 1140' is reduced.

[0075] In an advantageous implementation shown in FIG. 14, two fibers 1120 and 1140 may be arranged on and along the walls of the heating cavity 200.

[0076] In other advantageous embodiments, the light source is not incorporated into the device 1. In fact, ambient light 400, such as direct sunlight or scattered sunlight, may be used to illuminate at least a portion of the surface of the cavity 200. This is shown in the embodiments of FIGS. 15, 16, and 17.

[0077] FIG. 15 shows an embodiment of an optical contamination detection system disposed at the proximal end of the heating cavity 200. In the embodiment of FIG. 15, the detection system includes an optical element in the form of a window 20a that defines the boundary of the cavity 200 on the insertion end side of the cavity, a contamination detector 114a configured to measure the intensity of electromagnetic radiation that has passed through the window 20a, and a reference detector 114b disposed in the vicinity of the contamination detector 114a and configured to measure the intensity of electromagnetic radiation outside the body in the vicinity of the insertion end. The window 20a and the reference detector 114b are very close to each other, so the intensities of the radiation measured by the contamination detector 114a and the reference detector 114b are comparable. By monitoring the intensity I1 detected by the contamination detector 114a and the intensity I2 detected by the reference detector 114b, a signal I3 = I1 / I2 may be provided that is proportional to the absorption caused by contamination in the vicinity of the contamination detector 114a, for example, a contamination layer deposited on the contamination detector or on the window 20a that separates the contamination detector 114a from the cavity 200. If the contamination detector 114a is disposed without a window, the contamination detector 114a may have a protective layer on the side of the cavity 2w00. The protective layer may be, for example, a layer of SiO 2 or Al2O 3 and may be a layer.

[0078] Figures 16 and 17 show another configuration that does not require a built-in light source. In the aerosol generating device 1 or the aerosol generating system including the aerosol generating article 100, the optical contamination sensing system includes a lens 420 disposed on a side surface of the body of the aerosol generating device 1. The lens 420 directs the incident ambient light 400 toward the aerosol generating article 100 inserted into the longitudinal cavity 200, and the detector 114a, which is a contamination detector, is configured to detect the scattered light provided from the article 100. Figures 16 and 17 also show a reference sensor 114b disposed within the incident light beam. As shown in Figure 17, the reference detector 114b is preferably inserted into the space defined by the incoming light beam 400. The contamination detector 114a may be provided with a light shield 15 of the detector 114a facing the side of the incoming light on the back surface so that the light from the incoming light beam 400 is not detected by the back surface of the detector. In some variations not shown, the window 20 is not necessary, and the surface of the contamination detector 114a may serve as the surface on which contaminants accumulate.

[0079] In some variations, the ambient light may be provided by an external light source such as a perforated lamp or by a light emitter of a mobile phone. The method of the present invention may include the step of directing the lamp or the light emitter in the direction of the contamination detector 114a.

[0080] It is understood that the present invention is also achieved by the aerosol generating device 1 as well as by the aerosol generating system including the aerosol generating device 1 and the aerosol generating article 100 at least partially inserted into the device 1.

[0081] The present invention is also achieved by a method for controlling the aerosol generating device 1 described above in this specification. The method includes at least the following steps, namely, a) measuring the intensity of the electromagnetic radiation that has passed through at least one of the optical elements 20, 22, 23, 24, 25, 26, 27, 28 and / or has been reflected by at least one of those optical elements b) monitoring a parameter representative of the level of contamination of the heating cavity 200, based at least on the measured intensity; c) triggering an alarm system 60 in response to the parameter.

[0082] In some variants, the optical element 20 may be the front layer of the detector, such as a SiO2 layer, which is a protective layer in front of the detector 114. The optical element does not necessarily have to be a separate optical component arranged in front of the detector 114.

[0083] In one embodiment, the method further includes irradiating at least one of the optical elements 20, 22, 23, 24, 25, 26, 27, 28 with the electromagnetic radiation emitting system 12.

[0084] In one embodiment, the method further includes determining a reference intensity of the electromagnetic radiation emitting system 12, and in steps b) and c), the parameter is the ratio of the reference intensity to the measured intensity of the electromagnetic radiation that has passed through and / or has been reflected by at least one of the optical elements 20, 22, 23, 24, 25, 26, 27, 28.

[0085] In some embodiments, the method includes illuminating at least a portion of the surface of the aerosol-generating article 100 inserted into the aerosol-generating device 1, as shown, for example, in FIGS. 6, 16, and 17. In such embodiments, after the step of illuminating the surface of the article 100, a step of detecting at least a portion of the light scattered from the article 100 follows.

[0086] In some embodiments, the illuminating step may be provided by emitting infrared light from a heater. In some variations, an additional heating step may be provided. For example, it is possible to briefly heat the heater, for example for less than 1 second, so as to provide a temporary infrared flux to the detector. For example, the heater may be heated for less than 1 second above its normal operating temperature. Such an overheating step may mean a temperature that exceeds the average operating temperature by more than 50 degrees, and in some cases more than 100 degrees. In such embodiments, the heating flash is assumed to be so short that the consumable is only still heated and not burned.

Claims

1. An aerosol generating device (1), comprising a heater body and a longitudinally extending heating cavity (200) having an opening (210) at one insertion end (201) and adapted to receive at least a portion of an aerosol generating article (100) inserted through the opening (210). The aerosol generating device (1) further comprises: - at least one optical element (20, 22, 23, 24, 25, 26, 27, 28) disposed on or within the heater body and at least partially defining the boundary of the cavity (200); - at least one sensing system (10) including at least one electromagnetic radiation detection system (14) configured to measure the intensity of electromagnetic radiation that has passed through and / or been reflected by the optical element (20, 22, 23, 24, 25, 26, 27, 28), the at least one electromagnetic radiation detection system (14) including at least one detector (114); - a control system (50) configured to monitor an optical parameter representative of the level of contamination of the heating cavity (200) based at least on the measured intensity and to trigger an alarm system (60) in response to the parameter.

2. The aerosol generating device (1) according to claim 1, wherein the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28) includes a window that is at least partially transmissive to electromagnetic radiation.

3. The aerosol generating device (1) according to claim 1 or 2, wherein the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28) and the at least one detector (114) are disposed on the insertion end side of the cavity (200).

4. The aerosol generating device (1) according to any one of claims 1 to 3, including a plurality of sensing systems (10, 10', 10'') provided along the longitudinal direction (Z) of the cavity (200).

5. The aerosol generating device (1) according to any one of claims 1 to 4, further comprising a reference intensity detection system (142) configured to measure a reference intensity of electromagnetic radiation outside the longitudinal cavity and preferably in the vicinity of the optical elements (20, 22, 23, 24, 25, 26, 27, 28), wherein the control system (50) monitors a ratio of the reference intensity to the measured intensity of the electromagnetic radiation that has passed through and / or been reflected by the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28), and is configured to trigger an alarm system (60) according to the ratio.

6. The aerosol generating device (1) according to any one of claims 1 to 5, wherein the at least one sensing system (10) further comprises an electromagnetic radiation emission system (12, 12’, 12’’) comprising at least one emitter (112) configured to irradiate the optical element (20, 22, 23, 24, 25, 26, 27, 28).

7. The aerosol generating device (1) according to claim 6, wherein at least one electromagnetic radiation emitter (112) and at least one electromagnetic radiation detector (114) of the sensing system (10), preferably each emitter (112) and each electromagnetic detector (114), are arranged on the same side of the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28) along the lateral direction (X, Y) of the cavity (200).

8. The aerosol generating device (1) according to claim 6 or 7, wherein at least one electromagnetic radiation emitter (112) and at least one electromagnetic radiation detector (114) of the sensing system (10), preferably each emitter (112) and each electromagnetic detector (114), are arranged on opposite sides of the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28) along the lateral direction (X) of the cavity (200).

9. The aerosol generating device (1) according to claim 5 and any one of claims 6 to 8, wherein the reference intensity detection system including the reference detector (142) is configured to measure the reference intensity of the electromagnetic radiation emitted by the at least one electromagnetic radiation emitter (112).

10. The aerosol generating device (1) according to any one of claims 6 to 9, wherein the at least one electromagnetic radiation emitter (112) comprises a semiconductor emitter (112) that emits at a wavelength included between 300 nm and 10 μm, preferably between 300 nm and 5 μm.

11. The aerosol generating device (1) according to any one of claims 1 to 10, wherein the at least one electromagnetic radiation detector (114) is configured to measure the intensity of infrared light emitted by a heating element disposed around or inside the cavity (200), passing through and / or reflected by the optical elements (20, 22, 23, 24, 25, 26, 27, 28).

12. An aerosol generating system comprising the aerosol generating device (1) according to any one of claims 1 to 11 and an aerosol generating article (100) at least partially inserted into the cavity (200) of the aerosol generating device (1), wherein at least a portion of the aerosol generating article (100) faces at least one optical element (20, 22, 23, 24, 25, 26, 27, 28).

13. At least the following steps, namely, a) measuring the intensity of electromagnetic radiation passing through and / or reflected by the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28); b) monitoring a parameter representative of the level of contamination of the heating cavity (200) based at least on the measured intensity; and c) triggering an alarm system (60) according to the parameter, a method for controlling the aerosol generating device (1) according to any one of claims 1 to 11.

14. The method according to claim 13, wherein the parameter monitored in step b represents the level of dirt deposited on the surface of the heater body surrounding the cavity (200).

15. The method according to claim 13 or claim 14, further comprising irradiating the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28) with electromagnetic radiation, preferably visible light or infrared light.

16. The method according to claim 15, further comprising the step of determining a reference intensity of the electromagnetic radiation, wherein in steps b) and c), the parameter is a ratio of the reference intensity to the measured intensity of the electromagnetic radiation that has passed through and / or been reflected by the at least one optical element (20, 22, 23, 24, 25, 26, 27, 28).

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