Aerosol generating device having optical means for detecting a state

Abstract

The present invention relates to an electrically heated aerosol-generating device for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated. The device comprises a receiving cavity for removably receiving at least a portion of an aerosol-generating article including the aerosol-forming substrate to be heated. The device further comprises an electric heater for heating the aerosol-forming substrate when the article is received in the receiving cavity. In addition, the device comprises a condition detector for detecting the presence of at least one specific condition within the receiving cavity. The condition detector comprises a radiation emitter arranged and configured to emit radiation into the receiving cavity. The condition detector further comprises a radiation sensor arranged and configured to detect a portion of the emitted radiation that is reflected from the interior of the receiving cavity to indicate the presence of the at least one specific condition.

Description

[Technical field]

[0001] The present invention relates to an electrically heated aerosol generating device having means for detecting the presence of at least one particular condition within a receiving cavity of the device. [Background technology]

[0002] Aerosol generating devices used to generate inhalable aerosols by electrical heating of an aerosol-forming substrate are generally known from the prior art. Such devices may comprise a cavity for removably receiving at least a portion of an aerosol-generating article comprising the aerosol-forming substrate to be heated. The device further comprises an electric heater for heating the substrate when the article is received in the cavity. For various purposes, detection of certain conditions and states within the receiving cavity is important to ensure proper functioning of the device. For example, when the user takes a puff, it is important to accurately detect the user's puff in order to counter the change in heating temperature. In other cases, it may be necessary to detect the presence or displacement of an aerosol-generating article within the receiving cavity in order to enable or disable the heating process. Similarly, recognition of the article type may be required to ensure that only the appropriate article is used in the respective device. Such kind of condition detection is typically realized by sensor means arranged inside the cavity. Here, the sensor means is necessarily exposed to heat and moisture and even more so, in the case of induction heating devices, to high frequency electromagnetic fields. Often, such effects make the condition detection susceptible to interferences. In addition, the sensors may be damaged due to mechanical effects, especially during cleaning of the cavity or during insertion or removal of an article into or from the cavity. Summary of the Invention [Problem to be solved by the invention]

[0003] It would therefore be desirable to have an electrically heated aerosol generating device that has the advantages of, but is not limited to, the prior art solutions, and in particular, it would be desirable to have an electrically heated aerosol generating device that provides improved means for detecting the presence of at least one particular condition within the receiving cavity of the device. [Means for solving the problem]

[0004] According to the present invention, there is provided an electrically heated aerosol generating device for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated. The device comprises a receiving cavity for removably receiving at least a portion of an aerosol-generating article comprising the aerosol-forming substrate to be heated. The device further comprises an electric heater for heating the aerosol-forming substrate when the article is received in the receiving cavity. In addition, the device comprises a condition detector for detecting the presence of at least one particular condition within the receiving cavity. The condition detector comprises a radiation emitter arranged and configured to emit radiation into the receiving cavity. The condition detector further comprises a radiation sensor arranged and configured to detect a portion of the emitted radiation that is reflected from the interior of the receiving cavity and indicate the presence of the at least one particular condition.

[0005] In accordance with the present invention, it is recognized that a condition detector that emits radiation into the receiving chamber and detects radiation reflected from the interior of the receiving chamber advantageously allows for remote detection of conditions within the receiving cavity, such that the radiation emitter and radiation sensor may be disposed in a location away from any adverse conditions within the receiving chamber, such as heat, moisture, and electromagnetic fields.

[0006] Additionally, radiation-based condition detectors allow for fast and instantaneous condition detection without any delay between the occurrence of a particular condition or condition change and its detectability at the location of the condition detector.

[0007] In general, the condition detector may be configured to detect the presence of one particular condition within the receiving cavity, or to detect the presence of a number of different conditions within the receiving cavity. - detecting a puff by the user by detecting a change in intensity of reflected radiation due to a change in air density within the receptive cavity that occurs during the user's puff; - detecting the presence of an aerosol-generating article in the receiving cavity by detecting a change in the intensity of reflected radiation after insertion of the aerosol-generating article into the receiving cavity; - detecting the displacement of the aerosol-generating article within the receiving cavity by detecting a deviation of the intensity of the reflected radiation from a predefined value of the intensity of the reflected radiation, or - recognizing a particular type of aerosol-generating article received in the receiving cavity by detecting a predefined value of intensity of reflected radiation corresponding to the particular article type.

[0008] As used herein, the term "radiation" refers to electromagnetic radiation, in particular light, preferably visible light in the spectral range of 400 nm to 700 nm, and / or infrared (IR) light in the spectral range of 700 nm to 1 mm, in particular near infrared (NIR) light in the spectral range of 700 nm to 1.4 μm, and / or ultraviolet (UV) light in the spectral range of 100 nm to 400 nm.

[0009] As a result, the radiation emitter may be configured to emit radiation in the spectral range of 100 nm to 1400 nm, in particular 100 nm to 400 nm, and / or 400 nm to 700 nm, and / or 700 nm to 1400 nm. In particular, the radiation emitter may be configured to emit light in the spectral range of 100 nm to 1400 nm, in particular visible light in the spectral range of 400 nm to 700 nm, and / or infrared (IR) light in the spectral range of 700 nm to 1 mm, in particular near infrared (NIR) light in the spectral range of 700 nm to 1.4 μm, and / or ultraviolet (UV) light in the spectral range of 100 nm to 400 nm.

[0010] Accordingly, the radiation emitter may be a light emitter, in particular a visible light emitter or an infrared (IR) light emitter, in particular a near infrared (NIR) light emitter, or an ultraviolet (UV) light emitter.

[0011] The radiation emitter preferably comprises a light emitting diode (LED). LEDs are available at low cost and have an overall small and space saving size, which proves to be advantageous with regard to compact design of the condition detector. Depending on the spectral range of the emitted radiation, the radiation emitter may comprise a white or green or red or infrared LED, or a combination thereof. As used herein, green LED or red LED refers to an LED that emits radiation in a narrow band of wavelengths having green or red as primary color. These types of LEDs may also be denoted as monochromatic LEDs. Accordingly, the radiation emitter may comprise one or more monochromatic radiation sources. White diode refers to an LED that emits radiation in a broad band of wavelengths that spans most of the visible spectral range from 400 nm to 700 nm, or the entire visible spectral range from 400 nm to 700 nm. White LEDs may comprise individual LEDs that emit the three primary colors red, green, and blue, which are mixed to form white light. Alternatively, the white LED may contain phosphor material that converts the monochromatic light from a blue or UV LED into a broad spectrum white light, similar to a fluorescent lamp.

[0012] Preferably, the radiation detector comprises a photodiode. Like LEDs, photodiodes are also available at low cost and also have an overall small and space-saving size, which proves to be advantageous with regard to a compact design of the condition detector. The spectral sensitivity of the radiation detector is preferably selected to match at least a portion of the spectral range of the emitted radiation, i.e. the emission spectrum of the radiation emitter. For example, the radiation detector may comprise a silicon (Si) photodiode having a spectral sensitivity in the range of 190 nm to 1100 nm, or a germanium (Ge) photodiode having a spectral sensitivity in the range of 400 nm to 1700 nm, or an indium gallium arsenide (InGaAs) photodiode having a spectral sensitivity in the range of 800 nm to 2600 nm.

[0013] The radiation emitter and the radiation detector are preferably arranged outside the receiving cavity. Advantageously, this allows the radiation emitter and the radiation sensor to be completely isolated from any adverse conditions inside the receiving chamber. In addition, the arrangement outside the receiving cavity allows a simple cavity design. In particular, the cavity does not need to be equipped with any electrical feed-throughs for connecting the radiation emitter and the radiation sensor. For this reason, the cavity can have a closed inner surface. Advantageously, this also allows other parts of the aerosol generating device, such as, for example, electronic components, to be shielded from adverse effects originating from inside the cavity. Besides, the arrangement outside the receiving cavity prevents the sensor from being damaged, for example due to mechanical effects during cleaning of the cavity or during insertion or removal of an article into or from the receiving cavity.

[0014] It is preferred that the radiation emitter and radiation detector are not in fluid communication with the interior of the receiving cavity, which is clearly advantageous for the same reasons discussed above.

[0015] The radiation emitter and radiation detector may be separated from an interior of the receiving cavity by a wall member, the wall member forming at least a portion of the receiving cavity, in particular the wall member may form a portion of a wall defining the receiving cavity.

[0016] To allow radiation to be emitted into the receiving cavity and reflected outwardly towards the radiation sensor, the wall member is preferably optically transparent to at least a portion of the spectral range of the emitted and reflected radiation.

[0017] To ensure that a sufficient amount of radiation power can reach the inside of the receiving chamber and thereafter the radiation sensor (reflected radiation), the wall member may have an optical transmittance for at least a portion of the spectral range of the emitted and reflected radiation of at least 20 percent, in particular at least 50 percent, preferably at least 75 percent, even more preferably at least 80 percent. Preferably, the portion of the spectral range of the emitted and reflected radiation, respectively, whose transmittance is above one of the stated thresholds, covers 20% and in particular at least 50% of the spectral range of the emitted and reflected radiation.

[0018] In general, the wall member may be made of a material that is different from the material of the remainder of the wall that defines the receiving recess, or alternatively, the wall member may be made of the same material as the material of the remainder of the wall that defines the receiving recess.

[0019] The wall members may be made of one of the following materials: polytetrafluoroethylene (PTFE, also known as Teflon) and polyetheretherketone (PEEK). Such materials ensure sufficient transmittance. For example, for certain wavelengths, PTFE can be opaque to visible light, but transparent to other wavelength ranges.

[0020] The wall member may have a wall thickness in the range of 0.1 mm to 2 mm, in particular 0.15 mm to 1 mm, preferably 0.2 mm to 0.5 mm, where wall thickness means the transverse extension of the wall member, in particular perpendicular to the surface of the wall member that defines the inner surface of the receiving recess.

[0021] The receiving cavity may be provided with an insertion opening through which the aerosol-generating article may be inserted into the receiving cavity. As used herein, the direction in which the aerosol-generating article is inserted is denoted as the insertion direction. The insertion direction preferably corresponds to an extension of the length axis, in particular the central axis, of the receiving cavity.

[0022] After insertion into the receiving cavity, at least a portion of the aerosol-generating article may still extend outwardly through the insertion opening. The outwardly extending portion is preferably provided for interaction with a user, in particular for insertion into the user's mouth. Thus, during use of the device, the insertion opening may be proximate to the mouth. As a result, as used herein, the section proximate to the insertion opening or proximate to the user's mouth during use of the device, respectively, is denoted with the prefix "proximal". Sections that are disposed further away are denoted with the prefix "distal".

[0023] With this practice, the receiving cavity may be disposed or located in a proximal portion of the aerosol generating device, and the insertion opening may be disposed or located in a proximal end of the aerosol generating device, in particular in a proximal end of the receiving cavity.

[0024] Similarly, the receiving recess may be formed as a recess with a distal end portion and a proximal end portion, in particular as an elongated recess. If present, the insertion opening may be disposed at the proximal end of the receiving recess. At the distal end, the receiving recess may have a bottom portion opposite the insertion opening.

[0025] The wall member is preferably located at a distal end portion of the receiving recess. In particular, the wall member may form at least a portion of a bottom of the receiving recess. Alternatively, the wall member may form at least a portion of a distal end portion of a side wall of the receiving recess.

[0026] Accordingly, at least a part of the condition detector, in particular the radiation emitter and radiation sensor, may be disposed close to or adjacent to the distal end portion of the receiving cavity. In particular, the radiation emitter and radiation sensor may be disposed close to or adjacent to the bottom of the receiving cavity. Similarly, the radiation emitter and radiation sensor may be disposed close to or adjacent to a portion of the distal end portion of the sidewall of the receiving cavity. Such an arrangement is particularly advantageous in configurations of the device where the airflow through the cavity passes through the distal end portion of the cavity. In particular, this applies in cases where the airflow enters the aerosol-generating article at the distal end portion of the cavity after the aerosol-generating article is received in the cavity. For example, when the condition detector is used for puff detection, the arrangement of the condition detector close to or adjacent to these portions is advantageous, since these portions are most sensitive to changes in air density in the receiving cavity that occur during a user's puff.

[0027] In general, at least a portion of the condition detector, particularly the radiation emitter and radiation sensor, may be disposed proximate or adjacent to the wall member. In particular, at least a portion of the condition detector, particularly the radiation emitter and radiation sensor, may be disposed in or at least partially within the wall member. As mentioned above, the wall member may be part of a sidewall or a bottom of the receiving recess.

[0028] As used herein, the term "disposed in a wall member" means in particular that the respective component is disposed on a surface of the wall member opposite another surface of the wall member that forms at least a portion of the inner surface of the receiving recess.

[0029] Arrangement at least partially within the wall member may be advantageous as it reduces absorption effects and increases the response time of the condition detector. In addition, arrangement at least partially within the wall member advantageously allows compact integration of at least part of the condition detector, in particular the radiation emitter and radiation sensor, in the aerosol generating device. For example, at least part of the condition detector, such as the radiation emitter and radiation sensor, may be integrated into the wall member of the receiving cavity.

[0030] The radiation emitter and the radiation sensor may be part of the sensing unit. The sensing unit may comprise a support body on which the radiation emitter and the radiation sensor are mounted and which serves to mount the sensing unit within the device. For example, the device may comprise a pluggable recess located proximate a bottom portion of the receiving cavity and configured to receive the sensing unit. To hold the sensing unit securely within the pluggable recess, the support body may comprise one or more snap-fits that engage with corresponding snap-fits of the pluggable recess after insertion of the sensing unit into the pluggable recess.

[0031] In addition to the radiation emitter and the radiation sensor, the condition detector may further comprise electrical circuitry for controlling operation of the radiation emitter and / or converting an output signal of the radiation sensor into a signal indicative of the presence of at least one particular condition within the receiving cavity. The electrical circuitry may comprise at least one of a transimpedance amplifier for current-to-voltage conversion, an inverting signal amplifier, a single-ended to differential converter, an analog-to-digital converter, and a microcontroller.

[0032] The aerosol generating device may further comprise a controller operatively coupled to the condition detector, the controller being configured to determine the presence of at least one particular condition in the receiving cavity based on an output signal provided by the condition detector, in particular the radiation sensor, indicative of the presence of at least one particular condition in the receiving cavity.

[0033] The controller may further be configured to control the overall operation of the aerosol-generating device, in particular the heating process. Based on a signal indicating the presence of at least one particular condition in the receiving cavity, the controller may be configured to control the heating process in order to maintain the heating temperature at a certain level when the user puffs. Similarly, the controller may be configured to enable or start (preferably automatically) the heating process when the presence of an aerosol-generating article in the receiving cavity is detected, in particular by detecting a change in the intensity of the reflected radiation after the insertion of the aerosol-generating article into the receiving cavity. As another example, the controller may be configured to stop or disable the heating when a displacement of the aerosol-generating article in the receiving cavity is detected, in particular by detecting a deviation of the intensity of the reflected radiation from a predefined value of the intensity of the reflected radiation. As another example, the controller may be configured to enable or disable the operation of the device when a suitable or unsuitable article type received in the receiving cavity is recognized, in particular by detecting a predefined value of the intensity of the reflected radiation corresponding to the particular article type.

[0034] At least a portion of the controller and condition detector may be integral parts of the overall electrical circuitry of the aerosol generating device.

[0035] The aerosol generating device may include a power source, preferably a battery, such as a lithium iron phosphate battery. Alternatively, the power source may be another form of charge storage device, such as a capacitor. The power source may require recharging and may have a capacity that allows for storage of sufficient energy for one or more user experiences. For example, the power source may have a capacity sufficient to allow continuous generation of aerosol for about six minutes, or a multiple of six minutes. In another embodiment, the power supply may have a capacity sufficient to allow a predetermined number of puffs, or discontinuous activation of the heating device.

[0036] The aerosol generating device may comprise at least one air inlet in fluid communication with the receiving cavity, such that the aerosol generating system may comprise an air path extending from the at least one air inlet into the receiving cavity and optionally further through an aerosol-forming substrate and a mouthpiece within the article and into the mouth of the user.

[0037] Preferably, the air inlet is realized at an insertion opening of the receiving cavity used to insert the article into the cavity. When the article is received in the cavity, air may be drawn into the receiving cavity at the edge of the insertion opening and further through an airflow passage formed between the outer periphery of the aerosol-generating article and at least one or more portions of the inner surface of the receiving cavity.

[0038] The receiving cavity may comprise a number of protrusions extending into the interior of the receiving cavity. Preferably, the protrusions are spaced apart from one another such that an airflow passage is formed between adjacent protrusions, i.e. by a gap (free space) between adjacent protrusions.

[0039] In addition, the plurality of protrusions may be configured to contact at least a portion of the aerosol-generating article to retain the aerosol-generating article in the receiving recess.

[0040] At least one of the plurality of protrusions, in particular each of the plurality of protrusions, may comprise or be formed as a rib or may be a rib. The one or more ribs preferably extend along a length axis, in particular along a central axis, of the receiving recess. The length axis of the receiving recess preferably corresponds to an insertion direction along which the aerosol-generating article is insertable into the receiving recess.

[0041] The ribs may be arranged symmetrically around the length axis, particularly the central axis. In particular, the ribs may be arranged equally spaced around the length axis, particularly the central axis. Any of these configurations may be advantageous with respect to improved airflow management of the device. As mentioned above, the term "extending along the length axis, particularly the central axis" includes both an extension parallel to the central axis, as well as an extension generally in the direction of the central axis, which may be inclined (e.g., inclined by 2 degrees to 5 degrees) relative to the central axis, but still in a common respective plane with the central axis. The latter applies in particular to a substantially tapered, e.g. conical or frustoconical, shape of the receiving recess, as further described below.

[0042] The one or more ribs may have a substantially triangular cross-sectional shape. Alternatively, the one or more ribs may have a substantially rectangular or substantially trapezoidal, or substantially semi-elliptical or substantially semi-circular cross-sectional shape.

[0043] The one or more ribs may be provided with a contact surface that is preferably adapted to the shape of a respective portion of the aerosol-generating article that the contact surface will contact following insertion of the article into the receiving recess.

[0044] At least one of the plurality of protrusions, in particular each of the plurality of protrusions, may be chamfered or may comprise at least one chamfer. Preferably, each protrusion may be chamfered on a side facing towards the insertion opening of the receiving cavity or may comprise at least one chamfer facing towards the insertion opening of the receiving cavity. This advantageously facilitates the insertion of an article into the receiving cavity. Similarly, each protrusion may be chamfered on a side facing away from the insertion opening of the receiving cavity or may comprise at least one chamfer facing away from the insertion opening of the receiving cavity. Advantageously, this facilitates the removal of an article from the receiving cavity.

[0045] The aerosol generating device may comprise one or more end stops disposed in the receiving cavity, in particular at the distal end of the receiving cavity. The one or more end stops are preferably configured to limit the insertion depth of the aerosol-generating article into the receiving cavity. In particular, the one or more end stops may be configured to prevent the aerosol-generating article from abutting the inner surface of the receiving cavity at a distal end of the receiving cavity opposite the insertion opening of the receiving cavity at the proximal end of the receiving cavity. The one or more end stops therefore advantageously provide a free space in the distal portion of the receiving cavity, allowing free air flow between the distal end of the receiving cavity and the distal end of the aerosol-generating article when the article is received in the receiving cavity. The free space or gap volume in the distal portion of the receiving cavity adjacent the bottom of the cavity may advantageously serve as an aerosol detection cavity.

[0046] The one or more end stops may comprise a contact surface against which an aerosol-generating article, particularly a distal end of an aerosol-generating article, may abut when the article is received within the receiving recess.

[0047] Preferably, the aerosol generating device may comprise a plurality of separate end stops, for example three end stops disposed within the receiving cavity, in particular at the distal end of the receiving cavity.

[0048] The end stops may be symmetrically disposed about a length axis, particularly a central axis, of the receiving recess. In particular, the end stops may be equally spaced about a length axis, particularly a central axis, of the receiving recess. As mentioned above, this allows for free air flow around the end stops and the article received within the receiving recess.

[0049] The electric heater of the aerosol generating device may be an induction heater. The induction heater may comprise an induction source including an inductor configured to generate an alternating electromagnetic field, in particular a high frequency alternating electromagnetic field, in the receiving cavity. The alternating electromagnetic field, in particular a high frequency alternating electromagnetic field, may be in the range of 500 kHz (kilohertz) to 30 MHz (megahertz), in particular 5 MHz to 15 MHz, preferably 5 MHz to 10 MHz. After insertion of the article into the receiving cavity, the alternating electromagnetic field is used to inductively heat a susceptor in thermal contact or in thermal proximity with the aerosol-forming substrate to be heated. The inductor may be arranged to surround at least a portion of the receiving cavity or at least a portion of the inner surface of the receiving cavity, respectively. The inductor may be an inductor coil, for example a helical coil arranged in a sidewall of the receiving cavity. The inductor may be arranged to surround only a distal portion of the inner surface of the receiving cavity. Similarly, the inductor may be disposed to surround at least a medial axial portion of the inner surface of the receiving cavity, the medial axial portion being located between the distal and proximal portions of the inner surface of the receiving cavity.

[0050] Alternatively, the heater may be a resistive heater comprising a resistive heating element configured to heat when an electric current is passed through it due to the inherent ohmic resistance or resistive load of the resistive heating element. For example, the resistive heating element may comprise at least one of a resistive heating wire, a resistive heating track, a resistive heating grid, or a resistive heating mesh. During use of the apparatus, the resistive heating element is in thermal contact or thermal proximity with the aerosol-forming substrate to be heated.

[0051] In general, the receiving cavity may have any suitable shape. In particular, the shape of the receiving cavity may correspond to the shape of the aerosol-generating article to be received therein. Preferably, the receiving cavity may have a substantially cylindrical shape or a tapered shape, for example a substantially conical or substantially frustoconical shape.

[0052] Similarly, the receiving recess may have any suitable cross-section as seen in a plane perpendicular to the long axis of the receiving recess or perpendicular to the direction of insertion of the article. In particular, the cross-section of the receiving recess may correspond to the shape of the aerosol-generating article to be received therein. The receiving recess preferably has a substantially circular cross-section. Alternatively, the receiving recess may have a substantially elliptical cross-section, or a substantially oval cross-section, or a substantially square cross-section, or a substantially rectangular cross-section, or a substantially triangular cross-section, or a substantially polygonal cross-section. As used herein, the above mentioned shapes and cross-sections preferably refer to the shape or cross-section of the receiving recess without taking into account any protrusions.

[0053] The device may comprise a controller module and a receiving cavity module. Advantageously, this allows for modular assembly of the aerosol generating device. The controller module preferably comprises a controller and a power source. The receiving cavity module may comprise at least the receiving cavity, a radiation emitter, and a radiation detector. Preferably, the receiving cavity module may comprise at least a part of an electric heater, for example when the heater is an induction heater. The receiving cavity module may comprise an induction coil. The induction coil may be integrated into a wall defining the receiving cavity. For example, the induction coil may be integrated into the wall side of the receiving cavity, in particular so as to surround at least a part of the interior of the receiving cavity. The receiving cavity module may be formed as a tubular sleeve, which may be inserted into the controller module of the aerosol generating device.

[0054] Alternatively, at least a portion of the receiving cavity may be integrally formed with the main body of the aerosol generating device. Providing at least a portion of the receiving cavity as part of the main body may reduce the number of parts required to construct the aerosol generating device.

[0055] The present invention further relates to an aerosol-generating system comprising an aerosol-generating device according to the invention and as described herein, the system further comprising an aerosol-generating article comprising at least one aerosol-forming substrate heated by the device, at least a portion of the article being removably receivable or removably received in a receiving cavity of the device.

[0056] The aerosol-generating article may be a consumable product, in particular intended for single use. The aerosol-generating article may be a tobacco article. In particular, the article may be a rod-shaped article, preferably a cylindrical rod-shaped article that may resemble a conventional cigarette.

[0057] The article may comprise one or more of the following elements: a first support element, a base element, a second support element, a cooling element, and a filter element. Preferably, the aerosol-generating article comprises at least a first support element, a second support element, and a base element located between the first support element and the second support element.

[0058] All of the aforementioned elements may be disposed sequentially along the length axis of the article in the above-mentioned order, with the first support element being preferably disposed at the distal end of the article, and the filter element being preferably disposed at the proximal end of the article. Each of the aforementioned elements may be substantially cylindrical. In particular, all elements may have the same outer cross-sectional shape. In addition, the elements may be surrounded by an outer wrapper to keep the elements together and to maintain the desired cross-sectional shape of the rod-like article. The wrapper is preferably made of paper.

[0059] As used herein, the term "aerosol-forming substrate" refers to a substrate capable of releasing volatile compounds capable of forming an aerosol when heated. The aerosol-forming substrate may be a solid aerosol-forming substrate or a liquid aerosol-forming substrate. The aerosol-forming substrate may comprise a tobacco-containing material containing volatile tobacco flavor compounds that are released from the substrate upon heating. Alternatively, or in addition, the aerosol-forming substrate may comprise a non-tobacco material. The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerin and propylene glycol. The aerosol-forming substrate may also comprise other additives and ingredients, such as nicotine or flavoring substances. In particular, the liquid aerosol-forming substrate may comprise water, solvents, ethanol, plant extracts, and natural or artificial flavors. The aerosol-forming substrate may also be a paste-like material, a sachet of porous material containing the aerosol-forming substrate, or even loose tobacco mixed with, for example, a gelling or adhesive agent, which may include a common aerosol former such as glycerin, and then compressed or shaped into a plug.

[0060] The base element preferably comprises at least one aerosol-forming substrate to be heated. In case the aerosol generating system is based on induction heating, the base element may further comprise a susceptor in thermal contact with or in thermal proximity to the aerosol-forming substrate. As used herein, the term "susceptor" refers to an element comprising a material capable of being inductively heated in an alternating electromagnetic field. This may be the result of at least one of hysteresis losses or eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0061] At least one of the first support element and the second support element may comprise a central air passage. Preferably, at least one of the first support element and the second support element may comprise a hollow cellulose acetate tube. Alternatively, the first support element may be used to cover and protect the distal forward end of the base element.

[0062] The aerosol cooling element is an element having a large surface area and low draw resistance (e.g., 15 mmWG to 20 mmWG). In use, the aerosol formed by the volatile compounds released from the base element is drawn through the aerosol cooling element before being conveyed to the proximal end of the aerosol-generating article.

[0063] The filter element preferably functions as a mouthpiece or as part of a mouthpiece together with an aerosol cooling element. As used herein, the term "mouthpiece" refers to the portion of the article through which the aerosol exits the aerosol-generating article.

[0064] Additionally, the article may include an optical marker, which may be used to mark and identify a particular type of article, and the marker may be detectable by a status detector of the aerosol generating device when the aerosol generating article is received within the cavity of the device.

[0065] The optical marker is preferably a passive optical marker comprising a retroreflective material that reflects incoming radiation emitted from a radiation emitter towards a radiation sensor. For example, the optical marker may be a sticker attached to an outer surface of the aerosol-generating article. Accordingly, a particular type of such article may be recognized when received in a receiving recess by detecting a predefined value of intensity of the reflected radiation corresponding to the particular article type.

[0066] Further features and advantages of the aerosol generating system and aerosol generating article according to the invention have already been described above in relation to the aerosol generating device and apply equally.

[0067] The invention will now be further described, by way of example only, with reference to the accompanying drawings in which: [Brief description of the drawings]

[0068] [Figure 1] FIG. 1 illustrates generally in cross-section an exemplary embodiment of an aerosol generating device according to the present invention. [Diagram 2] FIG. 2 illustrates diagrammatically in a perspective view a receiving well module of the apparatus according to FIG. 1 with an aerosol-generating article introduced therein. [Diagram 3] FIG. 3 illustrates, in a perspective cross-sectional view, a receiving well module and an aerosol-generating article according to FIG. 2. [Figure 4] FIG. 4 illustrates diagrammatically the receiving well module according to FIG. 2 without an aerosol-generating article. [Diagram 5] FIG. 5 illustrates diagrammatically a cross-sectional view of a receiving well according to FIG. 4 without an aerosol-generating article. [Figure 6] FIG. 6 illustrates diagrammatically an embodiment of an aerosol generating device according to the invention in a first condition detection application. [Figure 7] FIG. 7 illustrates diagrammatically an embodiment of an aerosol generating device according to the present invention in a second condition detection application. [Figure 8] FIG. 8 illustrates diagrammatically an embodiment of an aerosol generating device according to the present invention in a third condition detection application.

[0069] 1 illustrates a schematic representation of an exemplary embodiment of an aerosol generating device 200 according to the present invention. The aerosol generating device 200 has an elongated shape and comprises a controller module 210 and a receiving well module 220. The well module 220 comprises a receiving well 221 for receiving at least a portion of an aerosol-generating article 2. The receiving well module 220 is inserted into a recess 230 formed in a proximal portion 211 of the controller module 210. In a distal portion 212, the controller module 210 comprises a power supply 250 and a controller 260 for powering and controlling the operation of the device 200. The aerosol generating device 200 and the aerosol-generating article 2 together form an aerosol generation system according to the present invention.

[0070] The aerosol generating device includes an inductor 240 in a proximal portion 211 of the controller module 210 that defines the cavity 230. In this embodiment, the inductor 240 is a helical coil disposed around the receiving cavity 221. The inductor 240 is part of an induction heater that is powered and operated by a power source 250 and a controller 260. During use of the device 200, the inductor 240 generates an alternating electromagnetic field in the receiving cavity 221 to inductively heat an aerosol-forming substrate contained in the article 2 when the article 2 is received in the receiving cavity 221. Alternatively, the inductor 240 may be part of the receiving cavity module 220.

[0071] 2, 3 and 4 show different embodiments of the receiving well module 220 with and without the aerosol-generating article 2. As can be seen, the receiving well module 220 is an elongated sleeve with an insertion opening 15 through which the aerosol-generating article 2 may be inserted at least partially into the receiving well 221. The insertion direction of the aerosol-generating article 2 extends substantially along the central axis 201 of the receiving well 221. The receiving well 221 is made of PEEK (polyetheretherketone). The receiving well 221 has a substantially cylindrical shape with a substantially circular cross section with a diameter of about 15 millimeters.

[0072] Corresponding to the shape of the receiving cavity 221, the aerosol-generating article 2 has a substantially cylindrical rod shape. As shown in Figures 1 and 3, the article 2 comprises five elements arranged sequentially along the length axis of the article 2, namely a first support element 25, a base element 24, a second support element 23 with a central air passage 26, a cooling element 22, and a filter element 21. The first support element 25 is arranged at the distal end of the article 2, and the filter element 21 is arranged at the proximal end of the article 2. Each of the aforementioned elements 21, 22, 23, 24, 25 is substantially cylindrical, and all of them have the same outer cross-sectional shape. In addition, the elements are surrounded by an outer wrapper to hold the elements together and maintain the desired circular cross-sectional shape of the rod-shaped article 2. The wrapper is preferably made of paper. The first support element 25 is used to cover and protect the distal front end of the base element 24. The base element 24 includes at least one aerosol-forming substrate to be heated. In addition, the base element 24 further comprises a susceptor (not shown) in thermal contact with the aerosol-forming substrate. Upon activation of the inductor 240, the susceptor heats up due to at least one of eddy currents or hysteresis losses induced by the electromagnetic field, depending on the electrical and magnetic properties of the susceptor material. The susceptor is heated until it reaches a temperature sufficient to vaporize the material from the aerosol-forming substrate. The released material may be entrained in an airflow passing through the article 2 from the first support element 25, through the base element 24, the second support element 23, and the cooling element 22 towards the filter element 21. In the process, the vaporized material cools to form an aerosol, which then leaks out through the filter element 21 at the proximal end of the article 2.

[0073] FIG. 5 illustrates further details of the receiving cavity module 220 and the receiving cavity 221, respectively. The receiving cavity 221 comprises an inner surface 16 with a plurality of first protrusions 10 and second protrusions 17. As can be seen in FIG. 1 and FIG. 3, when the article 2 is received in the cavity 221, the first support element 25 contacts the first protrusion 10 and the second support element 23 contacts the second protrusion 17. In contrast, the base element 24 does not have any contact with the inner surface 16 of the heating cavity 221. Advantageously, this leads to an overall reduction in heat loss, since there is no direct heat conduction from the aerosol-generating article 2 to the inner surface 16 in that portion of the cavity 221. Furthermore, the adverse effect of wetting of the article due to condensation formation in the cavity 221 is also reduced. In this embodiment, the first protrusion 10 and the second protrusion 17 are formed as ribs extending along a direction parallel to the central axis 201. The ribs are arranged symmetrically around the central axis 201 and equally spaced from each other. The spacing between adjacent ribs is in the range of 1.3 mm to 1.5 mm. With respect to its length extension, each rib is chamfered or provided with a respective chamfer at both ends, i.e. on the side facing the insertion opening 15 and on the opposite side facing away from the insertion opening 15. Advantageously, the chamfering facilitates the insertion and removal of the aerosol-generating article 2 into and from the receiving recess 221. Besides, each rib has a constant height extension along its length extension. In this embodiment, the height, measured in a radial direction towards the central axis 201, is in the range of 0.4 mm to 0.5 mm.

[0074] The first protrusions 10 and the second protrusions 17 are aligned, i.e., each of the first protrusions 10 is aligned with one of the second protrusions 17, respectively, as viewed in a direction parallel to the central axis 201. Due to this, the gaps (free spaces) between adjacent first protrusions 10 and between adjacent second protrusions 17 advantageously form multi-channel airflow passages 12 extending from the insertion opening 15 at the proximal end 4 of the receiving recess 221 to the bottom of the receiving recess 221 at its distal end 5.

[0075] As a result, when negative pressure is applied to the filter element 21 of the aerosol-generating article 2 received in the receiving cavity 221, for example when a user takes a puff, air is drawn into the receiving cavity 221 at the edge of the insertion opening 15 and further along the multi-channel airflow passage 12 into the bottom portion at the distal end 5 of the receiving cavity 221. Here, the airflow enters the aerosol-generating article 2 through the first support element 25 and further passes through the base element 24, the second support element 23, the aerosol cooling element 22, and the filter element 21, where it finally exits the article 2. At the base element 24, vaporized material from the aerosol-forming substrate is entrained in the airflow. The vaporized material and air are then cooled as they pass through the second support element 23, the aerosol cooling element 22, and the filter element 21, thereby forming an aerosol.

[0076] To enable proper redirection of the airflow into the aerosol-generating article 2 at the bottom portion of the receiving recess 221, the aerosol generating device 200 comprises three end stops 14 disposed at the distal end 5 of the receiving recess 221. The end stops 14 are configured to limit the insertion depth of the article 2 into the receiving recess 221 and thus prevent the article 2 from abutting against the bottom surface of the receiving recess 221. This is shown in FIG.

[0077] As mentioned above, detection of certain conditions and states within the receiving cavity is important for various purposes and reasons, such as ensuring proper functioning of the device. For example, it is important to accurately detect a user's puff in order to counter fluctuations in the heating temperature as the user puffs. In other cases, it may be necessary to detect the presence or displacement of an aerosol-generating article within the receiving cavity in order to enable or disable the heating process. Similarly, recognition of the article type may be required to ensure that only appropriate articles are used with the respective device.

[0078] For these purposes, the aerosol generating device 200 according to this embodiment comprises a condition detector 70 configured to detect the presence of at least one particular condition within the receiving cavity. To this end, the condition detector 70 comprises a radiation emitter 71 and a radiation sensor 72. As can be seen in Figures 1 and 5, the radiation emitter 71 is arranged and configured to emit radiation into the receiving cavity 221. Similarly, the radiation sensor is arranged and configured to detect a portion of the emitted radiation that is reflected from the interior of the receiving cavity 211 and that may therefore be indicative of the presence of at least one particular condition.

[0079] In this embodiment, condition detector 70 is located at a distal end portion of recess 221 opposite insertion opening 15. As will be explained in more detail below, this location is particularly suitable for detecting a number of different conditions and states within receiving recess 221.

[0080] In this embodiment, the radiation emitter 71 is a light emitting diode (LED) that emits red light at approximately 670 nm±50 nm.

[0081] The radiation sensor 72 is a photodiode having a spectral sensitivity that matches the spectral range of the light emitted by the radiation emitter 71. The photodiode is preferably a Si (silicon) photodiode.

[0082] 5, radiation emitter 71 and radiation sensor 72 are disposed adjacent to wall member 18 that separates radiation emitter 71 and radiation sensor 72 from the interior of receiving recess 221. Wall member 18 forms a portion of the bottom of receiving recess 221. Radiation emitter 71 and radiation sensor 72 are received within a recess 19 in a bottom wall of the receiving recess on the side opposite inner surface 16 of recess 221.

[0083] The wall member 18 is optically transparent for at least a portion of the spectral range of the emitted and reflected radiation so that a sufficient amount of radiation power passes from the radiation emitter 71 through the wall member 18 into the interior of the receiving chamber 211 and then (the reflected radiation) from the interior of the recess 221 back through the wall member 18 towards the radiation sensor 71. For example, the wall member 18 may have an optical transmittance of at least 20 percent, in particular at least 50 percent, preferably at least 75 percent, and even more preferably at least 80 percent for at least 20 percent of the spectral range of the emitted and reflected radiation. To this end, the wall member 19 is preferably quite thin, having a wall thickness in the range of 0.1 millimeter to 2 millimeters, in particular 0.15 millimeter to 1 millimeter, preferably 0.2 millimeter to 0.5 millimeter. For example, as in the present embodiment, for a light emitting diode (LED) emitting red light at about 670 nm±50 nm, the wall member 18 may be made of PEEK and may have a wall thickness of 0.2 mm.

[0084] In general, the wall member 18 may be made of a material that is different from the material of the remainder of the wall that defines the receiving cavity, or the wall member 18 may be made of the same material as the material of the remainder of the wall that defines the receiving cavity.

[0085] 1 and 5, the radiation emitter 71 and the radiation sensor 72 are part of a sensing unit 73. The sensing unit 73 comprises a support body 74 on which the radiation emitter 71 and the radiation sensor 72 are mounted and which serves to mount the sensing unit 73 to the receiving well module 220. As shown in FIG. 5, the receiving well module 220 comprises a pluggable recess 11 located at a bottom portion of the receiving well module 220 and configured to receive the sensing unit 73. To hold the sensing unit 73 securely in the pluggable recess 11, the support body 74 may comprise one or more snap fits that engage with corresponding snap fits of the pluggable recess 11 after insertion of the sensing unit 73 into the pluggable recess 11.

[0086] The sensing unit 70 further comprises electrical connector elements for operatively connecting the radiation emitter 71 and the radiation sensor 72 with an electrical circuit (not shown) of the condition detector 70. The electrical circuit is configured to control the operation of the radiation emitter 71 and to convert an output signal of the radiation sensor 72 into a signal indicative of the presence of at least one particular condition in the receiving cavity 221. The electrical circuit of the condition detector 70 may be an integral part of the controller 260. Based on the output signal provided by the condition detector 70, the controller 260 may take different actions to affect the operation of the device. This point will now be explained with respect to Figures 6, 7 and 8, which show different applications of the condition detector according to the present invention.

[0087] FIG. 6 illustrates a first application of the condition detector 70, which functions as a puff detector. The lower part of FIG. 6 shows the aerosol generating system in a state when the user takes a puff. In contrast, the upper part of FIG. 6 shows the aerosol generating system in a state between two puffs, i.e. when the user is not taking a puff. As explained above, when the user takes a puff, air is drawn through the receiving cavity 221. The airflow changes the air density in the receiving cavity 221. This applies in particular to the gap volume between the bottom of the receiving cavity 221 and the distal end of the aerosol-generating article 2, which is formed between the end stops 14 (see FIGS. 1 and 5). The change in air density is mainly due to the sidestream aerosol that fills the gap volume between puffs and is expelled from the gap volume when the user takes a puff. As a result, the gap volume adjacent to the bottom of the receiving cavity 221 functions as an aerosol detection cavity. The change in air density causes a change in the optical transmittance and absorbance properties of the gap volume. This in turn causes a change in the intensity of radiation emitted from radiation emitter 71, and thereafter reflected from the interior of receiving cavity 221 towards radiation sensor 72, which is detected. The change in intensity of the reflected light is therefore indicative of a user puff. Based on a corresponding output signal provided by condition detector 70 indicative of the occurrence of a user puff, the heating process may be adapted to counter fluctuations in heating temperature due, for example, to the cooling effect of airflow through the device during a user puff.

[0088] FIG. 7 illustrates diagrammatically a second application of the condition detector 70, which functions to detect the insertion or (non)presence of an aerosol-generating article 2 in a receiving cavity 221. The upper part of FIG. 7 shows the receiving cavity 221 before the insertion of an aerosol-generating article, while the lower part of FIG. 7 shows the receiving cavity 221 after the insertion of the article. As indicated by the arrows, the insertion of the article causes the radiation emitted from the radiation emitter 71 into the cavity 221 to be reflected differently compared to the situation without an article received in the cavity 221. As a result, the intensity of the reflected light detected by the radiation sensor 72 changes when the article 2 is being inserted into the cavity 2. Hence, the change in the intensity of the reflected light is indicative of the insertion or (non)presence of the aerosol-generating article 2 in the receiving cavity 2. Based on the corresponding output signal provided by the condition detector 70, which indicates the insertion or (non)presence of the article 2 in the cavity 221, the heating process can be enabled or disabled. Preferably, the device is configured to automatically initiate the heating process when the insertion or presence of an item 2 in the cavity 221 is detected by the condition detector 70 .

[0089] FIG. 8 illustrates diagrammatically a third application of the condition detector 70 functioning to detect displacement of the aerosol-generating article 2 from a predefined or desired position in the receiving cavity 221. Displacement of the article 2 may be due to mispositioning of the article 2 after insertion of the device into the receiving cavity 221 or during use due to some mechanical influence. The upper part of FIG. 8 illustrates the correct placement of the article 2 in the predefined or desired position in the receiving cavity 221, while the lower part of FIG. 8 illustrates the article displaced from the predefined or desired position (see dashed line). Similar to the other applications illustrated in FIG. 6 and FIG. 7, the displacement of the article 2 causes a deviation of the intensity of the reflected radiation from a predefined intensity value when detected by the radiation sensor 72. The predefined intensity value corresponds to the predefined or desired position. Hence, the deviation of the intensity of the reflected radiation is indicative of a displacement of the article 2. Based on the corresponding output signal provided by the condition detector 70 indicative of the displacement of the article 2 in the cavity 221, the heating process may be disabled.

Claims

1. 1. An electrically heated aerosol generating device for heating an aerosol-forming substrate capable of forming an inhalable aerosol when heated, comprising: - a receiving recess for removably receiving at least a portion of an aerosol-generating article comprising said aerosol-forming substrate; - an electric heater for heating the aerosol-forming substrate when the article is received in the receiving cavity; - a condition detector for detecting the presence of at least one particular condition within the receiving cavity, the condition detector comprising a radiation emitter arranged and configured to emit radiation into the receiving cavity and a radiation sensor arranged and configured to detect a portion of the emitted radiation that is reflected from the interior of the receiving cavity and indicates the presence of the at least one particular condition, wherein the radiation emitter and the radiation sensor are arranged outside the receiving cavity such that the radiation emitter and the radiation sensor are not in fluid communication with the interior of the receiving cavity, and at least a portion of the condition detector is arranged in close proximity to or adjacent to a distal end portion of the cavity.

2. The state detector, - detecting a puff by the user by detecting a change in intensity of reflected radiation due to a change in air density within the receptive cavity that occurs during the user's puff; - detecting the presence of the aerosol-generating article in the receiving cavity by detecting a change in the intensity of the reflected radiation after insertion of the aerosol-generating article into the receiving cavity; - detecting a displacement of an aerosol-generating article within the receiving cavity by detecting a deviation of the intensity of the reflected radiation from a predefined value of the intensity of the reflected radiation; - recognizing a particular type of the aerosol-generating article received in the receiving cavity by detecting a predefined value of the intensity of the reflected radiation that corresponds to the particular type of aerosol-generating article.

3. 3. An aerosol generating device according to any one of claims 1 to 2, wherein the radiation emitter is configured to emit radiation having a spectral range of 400 nm to 1300 nm.

4. An aerosol generating device as described in any one of claims 1 to 3, wherein the radiation emitter and the radiation sensor are separated from the interior of the receiving cavity by a wall member forming part of a wall defining the receiving cavity, the wall member being optically transparent to at least a portion of the spectral range of the emitted and reflected radiation.

5. 5. The aerosol generating device of claim 4, wherein the wall member has an optical transmittance of at least 20 percent, in particular at least 50 percent, for at least a portion of the spectral range of the emitted and reflected radiation.

6. 6. The aerosol generating device according to claim 4, wherein the wall member is made of polytetrafluoroethylene or polyetheretherketone.

7. 7. An aerosol generating device according to any one of claims 4 to 6, wherein the wall member has a wall thickness in the range 0.1 millimetres to 2 millimetres.

8. 8. An aerosol generating device according to any preceding claim, wherein the radiation emitter comprises a light emitting diode.

9. 9. An aerosol generating device according to any one of claims 1 to 8, wherein the radiation sensor comprises a photodiode.

10. 10. An aerosol generating device according to any one of claims 1 to 9, wherein the device comprises a controller module and a receiving well module, the receiving well module comprising the receiving well, the radiation emitter, and the radiation sensor.

11. An aerosol generating system comprising an aerosol generating device according to any one of claims 1 to 10 and an aerosol generating article removably received or receivable in the receiving cavity of the device.

12. The aerosol generating system of claim 11 , wherein the article comprises an optical marker.

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