WO2025016750A1

WO2025016750A1 - Aerosol generating systems and methods for operating aerosol generating systems

Info

Publication number: WO2025016750A1
Application number: PCT/EP2024/069017
Authority: WO
Inventors: Alec WRIGHT; Grzegorz Aleksander PILATOWICZ
Original assignee: JT International SA
Current assignee: JT International SA
Priority date: 2023-07-20
Filing date: 2024-07-05
Publication date: 2025-01-23
Anticipated expiration: 2026-01-20

Abstract

An aerosol generating system (10) comprises a heating region (36) operable to receive an aerosol generating substrate, a vapour outlet pathway (38) downstream of the heating region, and a controller. The system further comprises an image sensor (60) in optical communication with the vapour outlet pathway (38). The system is operable to heat an aerosol generating substrate received in the heating region (36) to generate an inhalable aerosol, capture an image (72, 78, 86) of a portion of the vapour outlet pathway during aerosol generation, analyse the image to identify one or more particles (80, 82) in the image, and analyse the particles identified in the image to distinguish between liquid particles (80) and solid particles (82).

Description

AEROSOL GENERATING SYSTEMS AND METHODS FOR OPERATING AEROSOL GENERATING SYSTEMS

Technical Field

The present invention relates generally to aerosol generating systems and methods for operating aerosol generating systems. An aerosol generating system is a hand-held inhaler system, typically comprising a heating region operable to receive an aerosol generating substrate and a controller operable to control the operation of the system.

Technical Background

The popularity and use of reduced-risk or modified-risk devices (also known as vaporisers) has grown rapidly in recent years as an alternative to the use of traditional tobacco products. Various devices and systems are available that heat or warm, rather than burn, an aerosol generating substrate to generate an aerosol for inhalation by a user.

Some aerosol generating systems are operable to generate an aerosol or vapour by heating a substantially solid aerosol generating substrate, which may be comprised within a consumable received in a heating region of the system. Systems of this type generate aerosol or vapour by heating the aerosol generating substrate to a temperature typically in the range 150°C to 300°C. Heating the aerosol generating substrate to a temperature within this range, without burning or combusting the aerosol generating substrate, generates a vapour which typically cools and condenses to form an aerosol for inhalation by a user of the system.

Other aerosol generating systems are operable to heat a liquid aerosol generating substrate in order to produce an aerosol or vapour which can be inhaled by a user. The liquid typically comprises an aerosol-forming substance, such as glycerine or propylene glycol, that creates the vapour when heated. Other common substances in the liquid are nicotine and various flavourings. Such liquid-based aerosol generating systems typically comprise a reservoir containing the liquid aerosol generating substrate and a liquid transport element operable to deliver the liquid substrate to the heating region. Such a heating region is also commonly termed a vaporisation zone. Heating is typically achieved by a heater, such as a resistive heater. Vaporisation occurs when the heater heats liquid present in the vaporisation zone until the liquid is transformed into vapour.

WO 2017/179043 discloses an example of an aerosol generating system of this latter type, which comprises a disposable cartridge and a reusable base part. The cartridge has a simplified structure which is achieved by keeping the main heating element in the re-usable base part, while the cartridge is provided with a heat transfer unit. The heat transfer unit is configured to transfer heat from the heating element to the proximity of liquid in the cartridge to produce a vapour for inhalation by a user.

In general terms, a vapour is a substance in the gas phase at a temperature lower than its critical temperature, which means that the vapour can be condensed to a liquid by increasing its pressure without reducing the temperature, whereas an aerosol is a suspension of fine solid particles or liquid droplets, in air or another gas. It should, however, be noted that the terms “aerosol” and “vapour” may be used interchangeably in this specification, particularly with regard to the form of the inhalable medium that is generated for inhalation by a user.

Sometimes during production of an aerosol by an aerosol generation system, damage to the system and/or a consumable in use with the system can result in unwanted components being present in the aerosol generated by the system. It can be desirable to know when the aerosol contains such unwanted components.

Summary

According to a first aspect of the present invention, we provide an aerosol generating system comprising a heating region operable to receive an aerosol generating substrate, a vapour outlet pathway downstream of the heating region, and a controller, the system further comprising an image sensor in optical communication with the vapour outlet pathway, the system operable to: heat an aerosol generating substrate received in the heating region to generate an inhalable aerosol, capture an image of a portion of the vapour outlet pathway during aerosol generation, analyse the image to identify one or more particles in the image, and analyse the particles identified in the image to distinguish between liquid particles and solid particles.

During use of an aerosol generating system a heater included in the system is typically heated quickly to a high temperature. In the case of a ceramic heater, for example, a temperature of 350-400°C may be attained in under a second, e.g. in approximately 300ms. After heating is completed, the heater then cools back to ambient temperature. Over time, repeated heating and cooling can cause components of the system, such as the heater, to degrade. Furthermore, damage to the system, for example due to an unexpected impact, can also cause damage to components of the system. Damage or degradation of this type can occasionally result in the release of solid particles, which in rare circumstances can enter into the vapour outlet pathway of the system. Damage to the system that is sufficient to generate such particles may indicate that the system is unsafe to use, for example because the heating element may be faulty or in need of replacement. Further, it may be undesirable for a user to inhale such particles. In addition, in the case of a heated substrate (“heat-not-burn”) system, damage to a consumable in use in the system can also result in the release of solid particles into the vapour outlet pathway. Again, it is undesirable for a user to inhale such solid particles, which may result in a bad taste.

By taking an image of the vapour outlet pathway, the present system is operable to obtain a real-time image of the vapour present in the vapour outlet pathway. This image is then analysed to determine whether one or more particles are present in the image. However, an aerosol, by its very nature, may include one or more liquid droplets (also referred to herein as liquid particles). Such liquid particles are a normal component of an aerosol, and are not typically problematic for a user to inhale. However, the presence of liquid particles in the vapour outlet pathway complicates the detection of unwanted solid particles in the vapour, since it cannot be inferred from the simple presence of particles in the vapour outlet pathway whether those particles are solid or liquid. The present system addresses this problem by analysing the identified particles to discriminate between liquid particles and solid particles. In this way it is possible to determine whether the vapour outlet pathway, and hence the vapour, contains only particles which are acceptable for inhalation (i.e. liquid particles) or whether it additionally contains particles which are unwanted (i.e. solid particles). Particles may be identified in an image by a suitable image analysis algorithm, such as a pixel counting algorithm. Solid particles may be distinguished from liquid particles by analysing characteristics of the identified particles, such as opacity, edge shape and/or edge structure.

The system may be further operable to determine an amount of solid particles present in the image, and to compare the amount to a first threshold. A small amount of solid particles may not be sufficient to indicate serious damage to the system and/or a consumable, or may not be detrimental to the user experience. Thus a threshold may be set below which the system operates as normal to avoid inconvenience to the user. Preferably the system does not exceed 10 solid particles per puff. The threshold number of particles in an image may therefore be 10, or fewer than 10, for example 2, 3, 4 or 5 particles.

If the amount of solid particles determined to be present in the vapour exceeds the first threshold, the system may be operable to issue an alert to a user of the system. In the case of a heat-not-burn system, for example, an alert may be appropriate as solid particles present in the vapour may be more likely to indicate damage to a consumable rather than to the system itself. In such a system, the alert may advise the user to replace the consumable, and/or to clean the system. Alternatively, or additionally, the system may be operable to terminate heating if the amount of solid particles determined to be present in the vapour exceeds the first threshold. Termination of heating may be accompanied by an alert indicating to the user that there is a system fault and/or that the system should be replaced or cleaned.

If the amount of solid particles determined to be present in the vapour does not exceed the first threshold, the system may be operable to continue heating, until such time as the heating reaches a natural conclusion, for example at the end of a user’s inhalation, or at the end of a usage session.

The system may be operable to capture a plurality of images during heating. The system may be operable, for each image of the plurality of images, to analyse each image to identify one or more particles in said image, and analyse the particles identified in said image to distinguish between liquid particles and solid particles. In this way, solid particles present in the vapour outlet pathway may be more reliably detected than if an image is taken only once during each heating session.

For each image of the plurality of images, the system may be operable to determine an amount of solid particles present in each image, to compare the amount to the first predetermined threshold, and, if the amount exceeds the first threshold, issue an alert to a user of the system and/or terminate heating. In the case of a damaged system and/or a damaged consumable, the amount of solid particles present in vapour produced by the system may increase over time, as a usage session progresses. By making a plurality of comparisons to the first threshold throughout a usage session unwanted solid particles may be more reliably detected. If, during the comparison, the amount is found not exceed the first threshold, the system may continue heating until such time as the heating reaches a natural conclusion, or the threshold is exceeded by a subsequent image.

For each image of the plurality of images, the system may be operable to determine a first amount of solid particles present in the image (also termed the “image under analysis”), and to compare that first amount to a second amount of solid particles determined to be present in a reference image, which may be for example an image preceding the image under analysis (such as an image immediately preceding the image under analysis). If the system determines that the first amount of solid particles exceeds the second amount of solid particles by a second predetermined threshold, the system may be operable issue an alert to a user of the system and/or to terminate heating. A sharp rise in solid particles present in the vapour outlet pathway during a usage session may be indicative of damage to one or both of the system and a consumable in use in the system, even if the total amount of particles is below the first threshold. Terminating heating and/or issuing an alert if the second threshold is exceeded may therefore provide an extra level of security to the user.

The image sensor may be a camera, such as a CMOS camera or CCD camera. The camera may have a footprint of 1mm x 1mm, or less. The camera may have a resolution of 249x250 or greater. Such an image sensor may be operable to provide an image of the vapour outlet pathway having sufficient resolution to distinguish reliably between liquid and solid particles, whilst remaining small enough to avoid the need to significantly increase the size of the aerosol generating system.

The image sensor may be located on a wall of the vapour outlet pathway, or may be located in a wall of the vapour outlet pathway. Thus the image sensor may be provided with an unobstructed view of the vapour outlet pathway.

The aerosol generating system may comprise a cartridge and a base part, with the heating region and the vapour outlet pathway being located in the cartridge and the controller being located in the base part. Such a system may be referred to as an electronic-cigarette, and typically generates a vapour from a liquid aerosol generating substrate, which may be held in a reservoir in the cartridge and delivered to the heating region by a fluid transfer element such as a porous ceramic wick. The base part may comprise a heater, such as a ceramic heater, which may in use be operable to transfer heat to the heating region in the cartridge via a thermal interface membrane. In such a system, the presence of solid particles in the vapour outlet channel may indicate damage to the heater, thermal interface membrane and/or fluid transfer element.

The image sensor may be provided either in the cartridge or in the base part. In the case that the image sensor is provided in the cartridge, one or more electrical connectors may be provided to deliver power to the image sensor in use from a power source located in the base part. In the case that the image sensor is provided in the base part, the cartridge may comprise a viewing portion in optical communication with the vapour outlet pathway, the viewing portion being operable to place the image sensor in optical communication with the vapour outlet pathway when the cartridge is operably connected to the base part. In this configuration no electrical power supply is required by the cartridge, simplifying the construction of the system. Alternatively, the aerosol generating system may comprise a heater operable to deliver heat to a heating chamber, which is operable to receive a consumable comprising the aerosol generating substrate. The heating chamber may comprise the heating region, and the vapour outlet pathway may be downstream of the heating chamber. Such a system may be referred to as a heated substrate system, or heat-not-burn system, and typically generates an aerosol from a solid aerosol generating substrate comprised in the consumable. In such a system, the presence of solid particles in the vapour outlet channel may indicate damage to the heater, the heating chamber and/or consumable.

The solid particles may be one or more of: tobacco, ceramic and metal.

It is to be appreciated that the aerosol generating system may further include any one or more components conventionally included in an aerosol generating system. Thus the features described above may be combined together if required, and may also be combined with features selected from the description below, in any combination.

According to a second aspect of the invention we provide a method of operating an aerosol generating system comprising a heating region operable to receive an aerosol generating substrate, a vapour outlet pathway downstream of the heating region, a controller and an image sensor in optical communication with the vapour outlet pathway, the method comprising: heating an aerosol generating substrate received in the heating region to generate an inhalable aerosol, capturing an image of a portion of the vapour outlet pathway during aerosol generation, analysing the image to identify one or more particles in the image, and analysing the particles identified in the image to distinguish between liquid particles and solid particles.

The method may further comprise: determining an amount of solid particles present in the image, comparing the amount to a threshold, and, if the amount exceeds the threshold, issuing an alert to a user of the system and/or terminating heating, or if the amount does not exceed the threshold, continuing heating.

The method may comprise: repeating the following steps during the step of heating: capturing an image of a portion of the vapour outlet pathway during aerosol generation, analysing the image to identify one or more particles in the image, analysing the particles identified in the image to distinguish between liquid particles and solid particles, determining an amount of solid particles present in the image, and comparing the amount to a threshold, and may further comprise: terminating heating if, for any image, the amount of solid particles present in the image exceeds the threshold.

The step of analysing the particles identified in the image to distinguish between liquid particles and solid particles may comprise analysing one or more of the edges of the particles identified in the image and the opacity of the particles identified in the image.

The aerosol generating system referred to in the method may be as described above in connection with the first aspect of the invention, the method may include any of the optional features set out above.

Brief Description of the Drawings

The invention will now be described, by way of example only, with reference to the accompanying drawings, in which like features are denoted with the same reference numerals.

Figure 1 is a schematic cross-sectional view of a first aerosol generating system comprising a cartridge for use with a base part (not shown);

Figure 2 illustrates a method of operating the aerosol generating system of Figure 1 ;

Figure 3 schematically illustrates a first image of a vapour outlet pathway;

Figure 4 schematically illustrates a second image of a vapour outlet pathway;

Figure 5 schematically illustrates a third image of a vapour outlet pathway;

Figure 6 graphically illustrates, for a plurality of images taken during a usage session, a comparison between a number of pixels and a first threshold;

Figure 7 illustrates an example image processing algorithm;

Figure 8 is a schematic cross-sectional view of a second aerosol generating system comprising a cartridge and a base part, with the cartridge disconnected from the base part;

Figure 9 is a schematic cross-sectional view of the second aerosol generating system of Figure 8, with the cartridge connected to the base part; and

Figure 10 is a schematic cross-sectional view of a third aerosol generating system. Detailed Description

Figure 1 shows one example of an aerosol generating system, which can be used as a substitute for a conventional cigarette. The aerosol generating system comprises a cartridge 14 (also referred to in the art as a “capsule” or “pod”) thermically connectable to a base part (not shown).

The cartridge 14 comprises a cartridge housing 27 having a proximal end 26 and a distal end 28. The proximal end 26 may constitute a mouthpiece end configured for being introduced directly into a user's mouth. In some examples, a mouthpiece may be fitted to the proximal end 26. The distal end 28 comprises one or more interface features (not shown) that are operable to connect the cartridge to the base part in use.

The cartridge 14 further comprises a reservoir 30 defining a reservoir chamber 32 configured for containing therein a liquid to be vaporised. The liquid may comprise an aerosol-forming substance such as propylene glycol and/or glycerol and may contain other substances such as nicotine and acids. The liquid may also comprise flavourings such as e.g. tobacco, menthol or fruit flavour. The reservoir 30 extends between the proximal end 26 towards the distal end 28 and is spaced from the distal end 28. A vapour transfer channel extends from one or more inlets 31 to an outlet 33 located centrally in the proximal end 26 of the cartridge. In the example shown, the reservoir surrounds, and coextends with, the vapour transfer channel. It will be appreciated that many other configurations forthe vapour outlet channel are possible. Further, the inlet(s) may be provided in the cartridge 14 as shown, or in the base part, as required.

The cartridge 14 is further provided with a fluid transfer medium 34, which in the example shown is a porous ceramic wick, in fluid communication with the reservoir chamber 32. The fluid transfer medium 34 is operable to absorb liquid aerosol generating substrate from the reservoir and deliver said liquid aerosol generating substrate to a heating region 36.

As used herein, the term “heating region” 36 refers to an area of the system in which aerosol generating substrate is heated to a sufficient temperature to produce a vapour. In the example shown, the heating region refers to the area in which liquid is vaporised, and thus may alternatively be termed a vaporisation chamber or vaporisation zone. In particular, in the example shown in Figure 1 , the heating region 36 is a region within the porous wick 34 in which liquid is heated to a sufficiently high temperature to achieve vaporisation I aerosolization. Vaporised liquid may then be entrained in air within the vapour transfer channel as said air flows past the wick, for example during a user’s inhalation. The portion of the vapour transfer channel which is downstream of the heating region 36 is referred to herein as a vapour outlet pathway 38. Thus, the vapour outlet pathway 38 refers to the portion of the vapour transfer channel that is expected, when the system is in use, to convey an aerosol from the heating region 36 to the outlet 33 for inhalation by a user of the system.

The distal end 28 of the cartridge 14 comprises a thermal interface membrane 50. The thermal interface membrane 50 is a thin membrane such as a metal foil that is configured to ensure rapid and even heating of the heating region 36 in an accurate and defined geometry, reducing the amount of lateral thermal spreading (i.e. thermal losses).

Although not shown in Figure 1 , a typical base part includes a housing accommodating therein a power supply unit, such as a battery, a heater, such as a ceramic heating element, and a controller. The controller is operationally connected to the heater, and power may be supplied to both from the power supply unit. The base part housing comprises one or more interface features configured to match the corresponding interface features of the cartridge 14, such that the cartridge 14 may be mechanically coupled to the base part.

The thermal interface membrane 50 located at the distal end 28 of the cartridge is flexible, and may be able to deform, and so at least partially conform, to the shape of the heater that is present in the base part when a connection is made between the cartridge 14 and the base part. Heat from the heater in the base part may thus be transferred to the heating region 36 through the thermal interface membrane 50 by conduction, convection and/or radiation (but primarily via conduction) when the cartridge is thermically connected to the base part in order to effect vaporisation of the aerosol generating liquid.

The cartridge shown in Figure 1 differs from conventional cartridges in that it additionally includes an image sensor 60 in optical communication with the vapour outlet pathway 38. In the example shown the image sensor is located in the vapour outlet pathway itself, and is secured to a wall 62 of the vapour outlet pathway 38 adjacent the outlet 33. The image sensor may be located in another position if preferred, for example within the vapour outlet pathway adjacent the heating region.

An example of a suitable image sensor is a camera, such as a CMOS camera or CCD camera. In the example shown in Figure 1 , the camera is an on-chip CMOS camera such as the NanEye miniature camera module marketed by ams OSRAM Group. The CMOS camera has a footprint of approximately 1 mm x 1 mm and a 249x250 pixel array, giving a pixel count in the region of 62,250. The pixels may be read out on a line by line basis in the manner of a rolling shutter at a frame rate in the range 43-62 frames per second.

In operation, the aerosol generating system is configured to carry out the method shown in Figure 2. In step 64, the system is operable to heat an aerosol generating substrate received in the heating region to generate an inhalable aerosol.

As discussed above, in the example shown in Figure 1 , heat may be supplied to the heating region from a heater located in the base part, which is operated under the control of a controller also located in the base part. The generated heat is transferred to the heating region 36 via the thermal interface membrane 50, so aerosolising liquid aerosol generating substrate that is present in the heating region to form an aerosol, which may be inhaled by a user via the vapour outlet pathway 38. Heating may be initiated in any conventional way, for example following detection of a user inhalation (also termed a puff) via a sensor, such as a flow sensor, or following manual activation of a user interface by the user, such as pressure on a button.

In step 66, the system is operable to capture an image of a portion ofthe vapour outlet pathway during aerosol generation. In particular, the image sensor 60 is operable to capture an image of the vapour outlet pathway. Because the heater is operating when the image is captured, the vapour outlet pathway includes aerosol when the image is captured. The image thus comprises an image of aerosol present in the vapour outlet pathway.

In step 68, the captured image is analysed to identify one or more particles in the image. In the example shown, the analysis is carried out in the base part by the controller, which comprises at least one microprocessor and a memory. Thus the captured image is stored, at least temporarily, in the memory whilst the microprocessor carries out analysis on the image.

Particles may be identified in the image by a suitable image processing algorithm. One example of a suitable algorithm is a pixel counting algorithm, wherein each pixel is assigned a value according to whether the pixel is considered “light” or “dark”. For example, a light pixel may refer to a pixel having an exposure value which does not differ by more than a specified amount from a calibration value obtained when an image was captured in the absence of any aerosol. Thus, a light pixel may refer to a pixel that is substantially unobscured in the image. In contrast, a dark pixel may refer to a pixel having an exposure value which is a specified amount less than the calibration value. A low exposure value may indicate that the pixel is wholly or partially obscured by an intervening item, such as a liquid or solid particle. In its most basic form, such an algorithm is able to identify dark pixels and light pixels within an image, whilst more complex algorithms are able to provide a quantification of the relative darkness of each pixel. These differences in pixel exposure can be used to determine that one or more particles are present in the image.

In step 70, the particles identified in the image are analysed to distinguish between liquid particles and solid particles. Again, in the example shown, the analysis is carried out in the base part by the controller. Thus the captured image is stored, at least temporarily, in the memory whilst the microprocessor carries out analysis on the image.

Although solid particles and liquid droplets may be of a comparable size, solid particles may have different physical characteristics from liquid particles. Solid particles may thus be distinguished from liquid particles by analysing the particles identified in the image as to how closely they match certain features considered to be characteristic of solid particles. One such example feature may be an opacity of the particle. For example, solid particles tend to have a greater opacity than liquid droplets. Thus darker particles (i.e. particles represented by pixels having an exposure below a certain predefined level) may be categorised as solid particles. Another example feature may be edge structure of the particle. For example, liquid particles tend to have smooth edges without irregular features. Thus, particles may each be assigned a regularity score based on edge shape, and the regularity score may be used to categorise each particle as solid or liquid. Alternatively or additionally, the edge sharpness of the particles may be considered. For example, a change in brightness and/or exposure gradient at the edge of a particle may be used to characterise whether the particle is solid or liquid. A particle having a sharp change in brightness will be a solid particle, whereas something more blurry (i.e. with a more gradual change in brightness) will be a liquid particle.

It will be appreciated that the categorisation methods discussed above are exemplary only, and that other methods of distinguishing between solid and liquid particles are available if preferred. Further, more than one particle categorisation method may be used in order to increase the accuracy of the determination.

Steps 66, 68 and 70 may be repeated during heating. That is, the image sensor may be operable to capture a plurality of images during heating, and the controller may be operable, for each respective image of the plurality of images, to analyse the respective image to identify one or more particles present in the image, and to analyse the identified particles to distinguish between liquid particles and solid particles. In the case of the example shown in Figure 1 , the CMOS camera operates a rolling shutter, such that images are taken continuously during heating. Figures 3, 4 and 5 schematically illustrate three example images of a vapour outlet pathway 38 captured by an image sensor 60 of the type shown in Figure 1 .

Figure 3 shows a first image 72, which can be seen to include a plurality of particles, and in particular liquid particles 80. Figure 3 also includes a processed version 72a of the first image 72, wherein each pixel in the image is assigned an exposure value, where relatively light pixels are illustrated as being white 74, whilst darker pixels (corresponding to particle locations) are illustrated in grey 76.

Figure 4 shows a second image 78, which can be seen to include a plurality of particles, and in particular liquid particles 80 interspersed with a number of solid particles 82. Figure 4 also includes a processed version 78a of the second image 78, wherein each pixel in the image is assigned a value according to its exposure, where relatively light pixels are illustrated as being white 74, whilst darker pixels (corresponding to liquid particle locations) are illustrated in grey 76 and the darkest pixels (corresponding to solid particle locations) are illustrated in black 84.

Figure 5 shows a third image 86, together with a processed version 86a of the third image. Like the processed second image 78a, each pixel in the processed third image 86a is assigned a value according to its exposure, where relatively light pixels are illustrated as being white 74, whilst darker pixels (corresponding to liquid particle locations) are illustrated in grey 76 and the darkest pixels (corresponding to solid particle locations) are illustrated in black 84. It can be seen that the processed third image includes a larger number of black pixels than the processed second image. This is because the third image includes more solid particles than the second image.

It will be appreciated that the images shown in Figures 3 to 5 are simplified for the purposes of illustration. In reality additional steps may be included prior to pixel counting, such as filtering and normalisation. Further, other image processing techniques may alternatively or additionally be used if preferred. For example, edge analysis may be performed in addition to pixel counting.

Once solid particles have been distinguished from liquid particles using an appropriate image processing algorithm, the system may be further operable to determine an amount of solid particles present in the image. For example, the controller may count the pixels that are assigned an exposure value indicating that they correspond to the presence of a solid particle. The amount of solid particles (as represented by the pixel count, for example) can then be compare with a first threshold.

Figure 6 shows a graphical representation of how the number of solid particles (represented by pixel count on the vertical axis) can vary between successive images taken one after the other during a heating session (represented by time on the horizontal axis). Figure 6 includes a function line 90 graphing the change in pixel count overtime. Figure 6 also illustrates a first threshold 92, which in this example takes the form of a predefined number of pixels.

As shown in Figure 6, in some images the amount of solid particles determined to be present in the vapour is below the first threshold, whilst in other images the amount of solid particles exceeds the first threshold. The system is configured to take different action depending on whether the amount of solid particles exceeds the first threshold or not.

For example, the system may be operable to terminate heating if the amount of solid particles determined to be present in the vapour exceeds the first threshold. In a cartridge-based e- cigarette system of the type shown in Figure 1 , solid particles in the vapour outlet pathway in an amount that exceeds the first threshold may indicate damage to the system, such as damage to the heater of the system, as such particles may be particles of ceramic and/or metal released from the heater surface. Termination of heating may be accompanied by an alert indicating to the user that there is a system fault and/or that the system should be replaced or cleaned.

Alternatively, if the amount of solid particles determined to be present in the vapour does not exceed the first threshold, the system is operable to continue heating, until such time as the heating reaches a natural conclusion, for example at the end of a user’s inhalation, or at the end of a usage session.

Each image taken by the system may be compared to the first threshold in this way. Thus, heating may be terminated if at any time the amount of solid particles in is found to exceed the first threshold..

Alternatively, or additionally, for each image of the plurality of images, the system may be operable to determine a first amount of solid particles present in an image under analysis, and to compare that first amount to a second amount of solid particles determined to be present in a reference image, which may be for example an image preceding the image under analysis, such as an image immediately preceding the image under analysis. If the system determines that the first amount of solid particles exceeds the second amount of solid particles by a second predetermined threshold, the system may be operable issue an alert to a user of the system and/or to terminate heating. Thus, the system may look at a rate of change in solid particles between adjacent images, as well as looking at a magnitude of solid particles present in any given image.

Figure 7 illustrates an image analysis algorithm in general terms. As shown, the algorithm starts at step 94, when an image is input to the algorithm. Optional pre-processing and filtering steps 96, 98 are then followed by a pixel counting step 100, which may be in line with the pixel counting process described above. The pixel count is then compared to a threshold in step 102. In the event of a fail (i.e. pixel count is equal to or exceeds the threshold), heating is terminated and/or an alert is issued to the user in step 104. Alternatively, in the event of a pass (i.e. pixel count does not exceed the threshold), the algorithm returns to the start and a new image is input.

Figures 8 and 9 show a cartridge 14a similar to the cartridge 14 of Figure 1. In the interest of conciseness, like reference numerals are used to depict like features, and the description of those features is not reiterated below.

Like the cartridge 14 of Figure 1 , the cartridge 14a includes a vapour outlet pathway 38 downstream of a heating region 36. However, rather than providing an image sensor on an internal surface 62 of the vapour outlet pathway, an image sensor 60a is instead provided in the base part 12. The cartridge 14a comprises a viewing portion 106 in optical communication with the vapour outlet pathway 38. The viewing portion 106 is operable to place the image sensor 60a in optical communication with the vapour outlet pathway when the cartridge is operably connected to the base part. In the example shown, the image sensor 60a protrudes from the base part on a protrusion 108, and is slidably received in a corresponding channel 110 of the cartridge when the cartridge 14a is engaged with the base part 12 in the direction of arrow A. The channel further comprises a window 112, such that the image sensor may view the vapour outlet pathway 38 without aerosol present in the vapour outlet pathway escaping into the channel 110.

Figure 10 shows another alternative aerosol generation system 10. The system 10 differs from those shown in Figures 1 , 8 and 9 in that it is a heated substrate system. Thus, rather than including a reservoir and an fluid transport element, the system includes a heating chamber 114 operable to receive a consumable 116 comprising an aerosol forming substrate 118. Like the systems of Figures 1 , 8 and 9 however, the system 10 includes a vapour outlet pathway 38 downstream of a heating region 36. The system 10 further includes an image sensor 60 in optical communication with the vapour outlet pathway. As described above, images captured by the image sensor during heating may be analysed to determine the presence of solid particles (as opposed to liquid particles) in the vapour outlet pathway. Such particles may indicate that a consumable present in the heating chamber is damaged, as in the case of damage to a consumable tobacco particles may be released from the consumable. On detection of solid particles exceeding a threshold number, the system may be operable to issue an alert to the user advising the user to replace the consumable and/or to clean the system.

The aerosol generating systems and methods described herein thus provide a way to identify unwanted solid particles in an aerosol generated by such a system. The systems and methods described herein thus advantageously provide a way to alert the user to potential damage to their device which would otherwise be difficult to identify. When potential damage is detected by the controller, the system may indicate this to a user, for example in the form of an alarm or alert via a user interface of the system. The controller may alternatively or additionally disable the heater of the device.

Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to the examples described herein without departing from the scope of the appended claims. In particular, different image analysis algorithms may be used, and/or the image sensor may be located in a different place, so long as it remains in optical communication with the vapour outlet pathway. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments.

Any combination of the above-described features in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

1. An aerosol generating system (10) comprising a heating region (36) operable to receive an aerosol generating substrate, a vapour outlet pathway (38) downstream of the heating region (36), and a controller, the system further comprising an image sensor (60) in optical communication with the vapour outlet pathway (38), the system operable to: heat an aerosol generating substrate received in the heating region (36) to generate an inhalable aerosol, capture an image (72, 78, 86) of a portion of the vapour outlet pathway (38) during aerosol generation, analyse the image (72, 78, 86) to identify one or more particles (80, 82) in the image, and analyse the particles identified in the image to distinguish between liquid particles (80) and solid particles (82).

2. The system of claim 1 , wherein the system is further operable to: determine an amount of solid particles (82) present in the image (72, 78, 86), compare the amount to a threshold (92), and, if the amount exceeds the threshold (92), issue an alert to a user of the system and/or terminate heating, or if the amount does not exceed the threshold (92), continue heating.

3. The system of claim 1 or claim 2, wherein the system is operable to capture a plurality of images (72, 78, 86) during heating, the system being further operable, for each image of the plurality of images, to: analyse each image (72, 78, 86) to identify one or more particles (80, 82) in said image, and analyse the particles identified in said image to distinguish between liquid particles (80) and solid particles (82).

4. The system of claim 3, wherein, for each image of the plurality of images (72, 78, 86), the system is further operable to: determine an amount of solid particles (82) present in each image, compare the amount to a threshold (92), and, if the amount exceeds the threshold (92), issue an alert to a user of the system and/or terminate heating, or if the amount does not exceed the threshold (92), continue heating.

5. The system of any preceding claim, wherein the image sensor (60) is a CMOS camera, the CMOS camera preferably having a footprint of less than 1mm x 1mm.

6. The system of any preceding claim, wherein the image sensor (60) is located on or in a wall (62) of the vapour outlet pathway.

7. The system of any preceding claim, wherein the system comprises a cartridge (14) and a base part (12), with the heating region (36) and the vapour outlet pathway (38) being located in the cartridge (14) and the controller being located in the base part (12).

8. The system of claim 7, wherein the image sensor (60) is provided in the base part (12), and wherein the cartridge (14) comprises a viewing portion (106) in optical communication with the vapour outlet pathway (38), the viewing portion (106) being operable to place the image sensor (60) in optical communication with the vapour outlet pathway (38) when the cartridge (14) is operably connected to the base part (12).

9. The system of any one of claims 1 -6, wherein the aerosol generating system comprises a heating chamber (114) operable to receive a consumable (116) comprising the aerosol generating substrate (118), the heating chamber (114) comprising the heating region (38).

10. The system of any preceding claim, wherein the solid particles (82) are one or more of: tobacco, ceramic and metal.

11. A method of operating an aerosol generating system comprising a heating region (36) operable to receive an aerosol generating substrate, a vapour outlet pathway (38) downstream of the heating region, a controller and an image sensor (60) in optical communication with the vapour outlet pathway (38), the method comprising: heating (64) an aerosol generating substrate received in the heating region (36) to generate an inhalable aerosol, capturing (66) an image (72, 78, 86) of a portion of the vapour outlet pathway (38) during aerosol generation, analysing (68) the image (72, 78, 86) to identify one or more particles (80, 82) in the image, and analysing (70) the particles identified in the image to distinguish between liquid particles (80) and solid particles (82).

12. The method of claim 11 , wherein the method further comprises: determining an amount of solid particles (82) present in the image, comparing the amount to a threshold (92), and, if the amount exceeds the threshold (92), issuing an alert to a user of the system and/or terminating heating, or if the amount does not exceed the threshold (92), continuing heating.

13. The method of any one of claims 11-12, wherein, the method comprises: repeating the following steps during the step of heating: capturing (66) an image (72, 78, 86) of a portion of the vapour outlet pathway during aerosol generation, analysing (68) the image to identify one or more particles (80, 82) in the image, analysing (70) the particles identified in the image to distinguish between liquid particles (80) and solid particles (82), determining an amount of solid particles (82) present in the image, and comparing the amount to a threshold (92).

14. The method of claim 13, wherein the method further comprises: terminating heating if, for any image, the amount of solid particles present in the image exceeds the threshold (92).

15. The method of any one of claims 11-14, wherein the step(s) of analysing (70) the particles identified in the image to distinguish between liquid particles and solid particles comprise(s) analysing one or more of the edges of the particles identified in the image and the opacity of the particles identified in the image.