Aerosol generating devices

Abstract

An aerosol generating device (10) comprises a thermal feedback unit (40) comprising: a first thermal adjustment element (42) configured to adjust a temperature of a surface (13) of the aerosol generating device; and a second thermal adjustment element (44) configured to adjust a temperature of the surface (13) of the aerosol generating device; and, a controller (22); wherein the thermal feedback unit (40) is operable to provide a thermal output to a user of the aerosol generating device (10) via the surface (13) of the aerosol generating device in response to a signal from the controller (22).

Description

[0001] AEROSOL GENERATING DEVICES

[0002] Technical Field

[0003] The present disclosure relates to an aerosol generating device, and in particular to a device that is configured to atomise or aerosolise an aerosol generating material to generate an aerosol for inhalation by a user. The present invention is particularly applicable to a portable (hand-held) aerosol generating device.

[0004] Technical Background

[0005] Devices which heat, rather than burn, an aerosol generating material to produce an aerosol for inhalation have become popular with consumers in recent years. A commonly available reduced-risk or modified-risk device is the heated material aerosol generating device, or so- called heat-not-burn device. Devices of this type generate an aerosol or vapor by heating an aerosol generating material, such as a non-liquid (e.g. solid) aerosol generating material, to a temperature typically in the range 150°C to 300°C. This temperature range is quite low compared to a conventional combustible cigarette. Heating the aerosol generating material to a temperature within this range, without burning or combusting the aerosol generating material, generates a vapor which typically cools and condenses to form an aerosol for inhalation by a user of the device. An aerosol may also be produced without heating (e.g., by using ultrasonic or chemical reaction), particularly if the device uses a liquid aerosol generating material.

[0006] 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.

[0007] An aerosol generating device is typically equipped with a user interface, which may be configured to provide information to a user, such as visual, audible or haptic feedback. For example, an aerosol generating device may provide a notification or alert to a user by means of a light, a screen, a sound or a vibration.

[0008] Summary

[0009] According to a first aspect of the invention there is provided an aerosol generating device comprising: a thermal feedback unit comprising: a first thermal adjustment element configured to adjust a temperature of a surface of the aerosol generating device; and a second thermal adjustment element configured to adjust a temperature of the surface of the aerosol generating device; and a controller; wherein the thermal feedback unit is operable to provide a thermal output to a user of the aerosol generating device via the surface of the aerosol generating device in response to a signal from the controller.

[0010] As noted above, aerosol generating devices may typically be equipped with a user interface which may be configured to provide information to a user, such as visual, audible or haptic feedback, via a user output interface such as a light, screen, speaker or vibratory element. An aerosol generating device according to the first aspect of the invention is able to alternatively (or additionally) provide a thermal output to a user utilising the thermal feedback unit. A “thermal output” as described herein means an output in the form of a temperature change (i.e. an increased or decreased temperature) at the surface of the device.

[0011] Such a thermal output may be used to replace or accompany an existing user output interface, and so may provide an alternative or improved means of conveying information to a user. Alternatively or additionally, such a thermal output may be used to enhance the sensory experience of a user during a session. The thermal output may be noticeable or otherwise discernible by a user as an increased or decreased temperature at a predefined portion of the surface, as compared, for example, to an ambient temperature of another portion of the device surface, or as compared to an ambient external temperature. Alternatively, the thermal output may not be immediately noticeable by the user, but may be used to adjust the surface temperature to improve user comfort (e.g. by preventing the surface of the device from becoming too hot, or too cold). The thermal output may comprise a temperature change in the order of 10°C or less, for example 5°C, 4°C, 3°C, 2°C or 1 °C.

[0012] By providing separate and distinct first and second thermal adjustment elements, the thermal feedback unit is able to quickly and reliably change between two different temperatures, so providing a simpler and more reliable thermal output than if only one thermal adjustment element had been provided.

[0013] The first thermal adjustment element may be configured to adjust, and in particular, to increase, a temperature of a first region of the surface of the aerosol generating device. More particularly, the first thermal adjustment element may be configured only to increase the temperature of the first region of the surface (i.e. the first thermal adjustment element may be configured such that it is only capable of heating, and not capable of cooling). The second thermal adjustment element may be configured to adjust, and in particular, to decrease, a temperature of a second region of the surface of the aerosol generating device. More particularly, the second thermal adjustment element may be configured only to decrease the temperature of the second region of the surface (i.e. the second thermal adjustment element may be configured such that it is only capable of cooling, and not capable of heating). The first region may be different to the second region, and may, for example be adjacent to the second region. The first and second thermal adjustment elements may be configured such that they do not operate at the same time, such that at any given time either the temperature of the first region may be increased, or the temperature of the second region may be decreased, but not both.

[0014] In this way, the first thermal adjustment element may be configured (only) to heat up a first region of the device surface, and the second thermal adjustment element may be configured (only) to cool down a second region of the device surface. This reduces the influence of the temperature of the first region of the device surface on the temperature of the second region, and vice versa. Thus, the heating up of the first region may progress rapidly to cause a user- perceivable temperature increase at the device surface, because the temperature of the first region may not be directly influenced by the temperature of the second region, and particularly by any cooling down that may have previously occurred. Similarly, the cooling down of the second region may progress rapidly to cause a user-perceivable temperature decrease at the device surface, because the temperature of the second region may not be directly influenced by the temperature of the first region, and particularly by any heating up that may have previously occurred. In this way, the thermal feedback unit allows for rapid temperature changes at the device surface regardless of how the thermal feedback unit has previously been operating, and particularly for rapid changes between heating and cooling. By locating the first and second regions adjacent to one another, temperatures changes in both the first and second regions may occur in generally the same portion of the device surface, and so may be perceived by a user as originating in the same general area of the device surface. This may enhance the user-perceptivity of the thermal output, making it more reliable as a notification means.

[0015] The thermal feedback unit may comprise a first plurality of first thermal adjustment elements, and a second plurality of second thermal adjustment elements. Each first thermal adjustment element may be configured to increase a temperature of a respective first region of the surface of the aerosol generating device, and each second thermal adjustment element may be configured to decrease a temperature of a respective second region of the surface of the aerosol generating device. More particularly, each first thermal adjustment element may be configured only to increase a temperature of a respective first region of the surface of the aerosol generating device, and each second thermal adjustment element may be configured only to decrease a temperature of a respective second region of the surface of the aerosol generating device. The thermal feedback unit may be configured to operate the first plurality of first thermal adjustment elements simultaneously, and in the same manner, such that the first plurality of first thermal adjustment elements operate together. Similarly, the thermal feedback unit may be configured to operate the second plurality of second thermal adjustment elements simultaneously, and in the same manner, such that the second plurality of second thermal adjustment elements operate together. The first plurality of first regions and the second plurality of second regions may be located within a predefined portion of the device surface. Use of a first plurality of first thermal adjustment elements and a second plurality of second adjustment elements within a predefined portion of the device surface may assist in creating the perception by a user that the entirety of the predefined portion is being either heated (by the first thermal adjustment elements) or cooled (by the second thermal adjustment elements) at any given time. This may thus increase the perception by the user that the thermal output occurs in the same location on the device surface, regardless of whether the thermal output is due to the first plurality of first thermal adjustment elements or the second plurality of second thermal adjustment elements.

[0016] Where there is a first plurality of first thermal adjustment elements and a second plurality of second thermal adjustment elements, the first and second thermal adjustment elements may be arranged alternately in one direction, and may also be arranged alternately in another direction different to the one direction. For example, the first and second thermal adjustment elements may be arranged one between the other in a first direction and also in a second direction perpendicular to the first direction, so as to be arranged in a chequerboard pattern. This arrangement may ensure that the pluralities of first and second thermal adjustment elements are evenly distributed over the predefined portion of the device surface, thus making the thermal feedback unit more efficient in providing a user-perceivable thermal output.

[0017] The aerosol generating device may further comprise a thermal insulator positioned between a first thermal adjustment element and a second thermal adjustment element. Where there is a first plurality of first thermal adjustment elements and a second plurality of second thermal adjustment elements, the aerosol generating device may comprise a thermal insulator positioned between each first thermal adjustment element and any adjacent second thermal adjustment element. Disposing a thermal insulator between adjacent first and second thermal adjustment elements may further reduce the impact of the temperature of the first region(s) on the temperature of the second region(s), and vice versa.

[0018] At least one of the first and second regions may comprise a material having a higher thermal conductivity than a different region of the surface of the aerosol generating device. Preferably each of the first and second regions comprises a material having a higher thermal conductivity than the different region of the surface of the aerosol generating device. For example, the first and second regions may comprise a metal material, whilst other portions of the device surface, and possibly the remainder of the device surface, may comprise a plastics material. Providing a material having the higher thermal conductivity in one or both (or each) of the first and second regions may make the thermal feedback unit more efficient in providing the user-perceivable thermal output.

[0019] The aerosol generating device may comprise a housing, which may define at least a portion of the surface of the aerosol generating device. The (or each) first region may comprise a first specified portion of the housing and the (or each) second region may comprise a second specified portion of the housing different to the first. The first and second specified portions may be indistinguishable from the remainder of the housing, so as to provide the thermal output in a subtle manner, or may be indicated visually on the housing, e.g. by colour, texture, text or other insignia. The first and second portions of the housing may have a higher thermal conductivity than the remainder of the housing, and may, for example, be thinner or comprise a different material than adjacent portions of the housing.

[0020] The aerosol generating device may be non-round, and may for example have a generally rectangular, stadium-shaped or elliptical cross section, such that the aerosol generating device has a narrow face and a wide face. The thermal feedback unit may be operable to provide the thermal output at the narrow face. An aerosol generating device having such a cross section may typically be held in one hand of a user such that the fingers of the user curl around the narrow face. This configuration may make it easier for user to perceive the thermal output at their finger crease, which may be more perceptive to small temperature changes than, for example, the user’s palm.

[0021] The aerosol generating device may further comprise a heating arrangement configured to supply heat to an aerosol generating substrate in order to generate an aerosol for inhalation by a user of the aerosol generating device. For example, the aerosol generating device may comprise a heating chamber, and the heating arrangement may be configured to supply heat to the heating chamber. The heating chamber may be substantially cup shaped, and may have an open first end operable to receive a non-liquid (e.g. solid) consumable. For example, the heating chamber may comprise a substantially cylindrical side wall that is open at a first end, so defining the open first end, and closed at a second end, defining a base to the heating chamber. The heating arrangement may be external to the heating chamber, and may be wrapped around the heating chamber. The heating arrangement may be provided in addition to the thermal feedback unit. During use, heat from the heating arrangement may “leak” to a surface of the aerosol generating device as an indirect consequence of heating an aerosol generating substrate to generate an aerosol for inhalation. The thermal feedback unit may be configured to provide a deliberate thermal output that is distinguishable by a user as being distinct from any such leaked heat. The thermal feedback unit, and in particular the second thermal adjustment element(s), may be configured to reduce the user perception of such leaked heat, by actively cooling the device surface.

[0022] The controller may be operable to signal the thermal feedback unit to provide the thermal output to the user in response to a control input. The control input may comprise one or more of: a type of aerosol generating substrate to be heated by the aerosol generating device, a detected temperature of a region of the aerosol generating device (such as a surface temperature or heater temperature), a detected temperature of a region of the user (such as a user’s finger, palm or lip), a temperature of the external environment (such as a measured or received external temperature), a user input received by the aerosol generating device, a detected user inhalation. The controller of the aerosol generating device may be operable to select a thermal profile for the thermal output based on the control input.

[0023] In one example, the aerosol generating device may be configured for use with a plurality of different types of consumable, each of which may comprise a different type of aerosol generating substrate. The controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles according to a type of aerosol generating substrate. For example, the aerosol generating device may comprise an article detection unit for distinguishing between one or more types of consumable, and the controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles when a certain type of consumable is detected. The thermal feedback unit thus offers a unique and sophisticated way of notifying the user of the detection of the consumable. Furthermore, the thermal profile may differ throughout a usage session depending on the type of consumable, further enhancing user the experience.

[0024] In one example, the aerosol generating device may comprise a temperature sensor for measuring at least one of: a temperature at a certain location in or on the device, an ambient temperature external to the device, and a temperature of a region of a user touching the device (e.g. the user’s palm or finger). The controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles according to a measured temperature. For example, the thermal feedback unit may be controlled to provide the thermal output at the surface of the aerosol generating device at a temperature which is selected relative to the measured temperature. In this way, user-perceptivity of the thermal output may be improved, for example by ensuring that the thermal output is clearly discernible from the measured temperature. Alternatively or additionally, where the temperature sensor is operable to measure a temperature at a certain location in or on the device. The thermal feedback unit may be controlled to maintain the measured temperature at, below or above a predefined value. In this way user comfort may be improved, by ensuring that a surface temperature of the device does not exceed a predefined maximum value, or fall below a predefined maximum value.

[0025] In a further example, the controller of the aerosol generating device may be operable to receive a user input, for example via a user interface of the aerosol generating device or of a connected device. The controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles according to the received user input. Such a user input may include, for example, an indication of a type of consumable inserted, or an indication of a user preference. In this way, the user sensory experience may be improved, by tailoring the thermal output according to the preference of the user.

[0026] A thermal profile may comprise adjusting a temperature, for example a set temperature of one of the first and second regions, to a selected value. For example, the thermal profile may comprise increasing the temperature of the first region to a first set temperature. Alternatively, the thermal profile may comprise decreasing the temperature of the second region to a second set temperature. In this way the user may be provided quickly with an increase or decrease in temperature at the surface of the aerosol generating device for a temporary period (e.g. 1-5 seconds) following the control signal. Such a temporary change in temperature may be useful in providing a notification to the user.

[0027] A thermal profile may comprise adjusting a temperature, for example a set temperature of one of the first and second regions, to a selected value and then maintaining the temperature at that selected value until an end of a usage session (e.g. for 2-3 minutes). For example, the thermal profile may comprise increasing the temperature of the first region to a first set temperature and then maintaining the temperature at that set temperature until an end of a usage session. Alternatively, the thermal profile may comprise decreasing the temperature of the second region to a second set temperature and then maintaining the temperature at that set temperature until an end of a usage session. In this way the user experience of the session may be modified by the thermal output. For example, the user may experience a feeling of increased warmth, or of increased freshness, during the session.

[0028] A thermal profile may comprise adjusting a temperature, for example a set temperature of one of the first and second regions, to a selected value at a plurality of discrete times during a usage session. A thermal profile may comprise adjusting a temperature, for example a set temperature of one of the first and second regions, according to a selected pattern. In this way the user sensory experience throughout the session may be modified by the thermal output. Furthermore, a thermal output following a recognisable pattern may be useful in providing a notification to the user.

[0029] In one example, the aerosol generating device may further comprise a puff detector operable to detect a user inhalation. The thermal output may provided to the user on detection of a user inhalation. For example, a set temperature of one of the first and second regions may be adjusted to a selected value each time a user inhalation is detected. In this way the user sensory experience of the session may be modified by the thermal output. For example, the thermal output may be provided as a decrease in temperature each time a user inhalation is detected, which may increase the perception of the user as regards the depth of their inhalation. The temperature of the thermal output may be selected by the controller in proportion to a detected amount of the user inhalation. For example, the thermal output may be controlled such that a deeper user inhalation is paired with a greater decrease in temperature of the thermal output.

[0030] In any of the abovementioned examples, the thermal profile may be selected based on more than one control input, e.g. both a consumable type and a measured temperature.

[0031] The thermal feedback unit may be arranged such that the thermal feedback does not exceed a predefined maximum temperature, and / or does not fall below a predefined minimum temperature, regardless of the thermal profile that is selected.

[0032] The thermal feedback unit may be operated by the controller to cool the device surface if a region of the surface is detected to be unacceptably hot, e.g. greater than 50°C, or greater than 45°C.

[0033] The thermal feedback unit may be controlled to confine the total amount of energy consumed for the thermal output within a prescribed limit during any single aerosol generating session. This effectively avoids excessive energy consumption due to the thermal output, and so may assist in preserving battery life.

[0034] At least one of the first and second thermal adjustment elements may comprise a thermoelectric element, such as a Peltier element. Preferably, both (or each) of the first and second thermal adjustment elements comprise thermoelectric elements, such as Peltier elements. Thermoelectric elements may be configured for either heating or cooling, depending on the direction of current flow across the thermoelectric element, and so present a reliable and convenient way of implementing a thermal feedback unit. Such elements have particular utility when used in pairs, with one element cooling and one element heating, as in the present case, because there is no need to dynamically change the direction of the current flow, which would be necessary if a single thermoelectric element were used for both heating and cooling. Thus, preferably, the each first thermal adjustment element may comprise a first thermoelectric element and each second thermal adjustment element may comprise a second thermoelectric element, wherein a hot side of each first thermoelectric element faces towards each respective first region of the surface and a cold side of each second thermoelectric element faces towards each respective second region of the surface.

[0035] Where the aerosol generating device comprises a heating arrangement, the first thermal adjustment element may comprise a heat transfer member which can be actuated to form a thermal connection between the heating arrangement and the first region, thereby increasing the temperature of the first region, and also to release the thermal connection, in a selective manner. An example of such a heat transfer member may be a thermal bridge that is pivotable or rotatable between a first position in which the thermal connection is made a second position in which the thermal connection is released. Such a thermal adjustment element offers a reliable and convenient way of increasing the temperature of the first region of the device surface by utilising waste heat from the heating arrangement.

[0036] Features of the above aspects of the invention may be combined together, as well as with features selected from the description or the technical background, in any order, unless expressly stated otherwise.

[0037] Brief Description of the Drawings

[0038] The present invention will now be described in more detail, by way of example only, with reference to the accompanying drawings, in which:

[0039] Figure 1 is a diagrammatic cross-sectional view of an aerosol generating system comprising an aerosol generating device and a consumable positioned in a heating chamber of the aerosol generating device;

[0040] Figure 2 is a schematic illustration of a first example thermal feedback unit for use in an aerosol generating device;

[0041] Figure 3 is a schematic illustration of a second example thermal feedback unit for use in an aerosol generating device;

[0042] Figure 4 is a schematic illustration of a third example thermal feedback unit for use in an aerosol generating device;

[0043] Figure 5 is a schematic illustration of a fourth example thermal feedback unit for use in an aerosol generating device;

[0044] Figure 6 is a perspective view of an aerosol generating device; Figure 7 is a schematic cross-section through the aerosol generating device of Figure

[0045] 6;

[0046] Figure 8 is a schematic cross-section through a fifth example thermal feedback unit in an aerosol generating device in a first condition;

[0047] Figure 9 is a schematic cross-section through the fifth example thermal feedback unit in an aerosol generating device in a second condition;

[0048] Figure 10 shows first and second examples of a thermal profile; and

[0049] Figure 11 shows a third example of a thermal profile.

[0050] Detailed Description

[0051] Referring initially to Figure 1 , there is shown diagrammatically an example of an aerosol generating system 1 . The aerosol generating system 1 comprises an aerosol generating device 10 and a consumable 100, also referred to herein as an aerosol generating article, for use with the device 10. The aerosol generating device 10 comprises a main body 12 operable to house various components of the aerosol generating device 10. The main body 12 comprises an outer surface 13, which defines the external shape of the aerosol generating device. The main body 12 may have any shape that is sized to fit the components described in the various examples set out herein, and to be comfortably held by a user unaided, in a single hand.

[0052] A first end 14 of the aerosol generating device 10, shown towards the bottom of Figure 1 , is described for convenience as a distal, bottom, base or lower end of the aerosol generating device 10. A second end 16 of the aerosol generating device 10, shown towards the top of Figure 1 , is described as a proximal, top or upper end of the aerosol generating device 10. During use, the user typically orients the aerosol generating device 10 with the first end 14 downwards and / or in a distal position with respect to the user’s mouth and the second end 16 upwards and / or in a proximal position with respect to the user’s mouth.

[0053] The aerosol generating device 10 comprises a heating chamber 18 positioned in the main body 12. The heating chamber 18 defines an interior volume in the form of a cavity 20 having, in this example, a substantially cylindrical cross-section. The cavity 20 of the heating chamber 18 is open towards the second end 16 of the aerosol generating device 10. The heating chamber 18 has a longitudinal axis defining a longitudinal direction and is formed of any suitable heat- resistant material, such as a heat resistant plastic material, e.g. polyether ether ketone (PEEK), or a metal material, such as stainless steel.

[0054] A heating arrangement 22 is located in proximity to the heating chamber 18 and is operable to provide heat to the heating chamber. The aerosol generating device 10 further comprises a power source 26, for example one or more batteries which may be rechargeable, and a controller 24. The controller 24 may comprise one or more integrated circuits and other electrical components, such as a microcontroller unit (MCU) and / or microprocessor unit (MPU).

[0055] The controller 24 couples the power source 26 to the heating arrangement 22. The controller 24 may also be connected to a user interface 23 comprising inputs such as a power button for receiving commands from a user and / or outputs such as indicator lights, a display screen or an audible or vibratory output device for providing information to the user. The controller 24 may also be connected to an antenna 25 for wireless communication with a remote device such as the user’s smartphone, which can be used for input and output, as well as for relaying data between the aerosol generating device 10 and external entities such as its manufacturer.

[0056] The heating chamber 18, and specifically the cavity 20, is arranged to receive a correspondingly shaped generally cylindrical or rod-shaped aerosol generating article 100, also termed herein a consumable. Typically, the aerosol generating article 100 comprises a pre-packaged solid (i.e. non-liquid) aerosol generating substrate 102. The aerosol generating article 100 is a disposable and replaceable article, which may, for example, contain tobacco as the solid aerosol generating substrate 102. The aerosol generating article 100 has a proximal end 104 (or mouth end) and a distal end 106. The distal end 106 is inserted into the heating chamber 18 of the aerosol generating device 10 so that at least the aerosol generating substrate 102 is contained within the heating chamber 18. The aerosol generating article 100 further comprises a mouthpiece segment 108 positioned downstream of the aerosol generating substrate 102. At least part of the mouthpiece segment 108 projects from the heating chamber 18 so that the proximal end 104 of the aerosol generating article 100 is accessible to be taken into the mouth of a user. When the aerosol generating device 10 applies heat to the aerosol generating article 100, heated vapour is emitted from the aerosol generating substrate 102. As inhalation by the user draws air towards the proximal end 104 of the aerosol generating article 100, the vapour cools and condenses as it passes through the mouthpiece segment 108 to form an aerosol with characteristics suitable for inhalation. The mouthpiece segment 108 may further comprise a filter (not shown) to remove particles or drops above a certain size from the airstream.

[0057] The aerosol generating substrate 102 and the mouthpiece segment 108 are arranged in coaxial alignment inside a wrapper 110 (e.g., a paper wrapper) to hold the components in position to form the rod-shaped aerosol generating article 100. The wrapper 110 typically does not cover the ends 104, 106 of the aerosol generating article 100 in order that air can flow through the aerosol generating article 100 from the distal end 106 to the proximal end 104. In the illustrated embodiments of the invention, the heating chamber 18 comprises an open first end 28 and a closed base 30 at a second end. That is, the heating chamber 18 is cup shaped. This can ensure that air drawn from the open end 28 is guided around the consumable towards the base 30, at which point the air is drawn through the aerosol generating substrate 102.

[0058] The aerosol generating device 10 may optionally include a sliding cover (not visible in Figure 1) moveable between a closed position in which it covers the open first end 28 of the heating chamber 18 and an open position in which it exposes the open first end 26 of the heating chamber 18 to provide access to the heating chamber 18. The sliding cover may be biased towards the closed position if required.

[0059] In accordance with the present disclosure, an aerosol generating device, such as the exemplary aerosol generating device 10 shown in Figure 1 , further comprises a thermal feedback unit 40. The thermal feedback unit 40 includes a first thermal adjustment element 42 and a second thermal adjustment element 44. Both the first and second thermal adjustment elements 42, 44 are configured to adjust a temperature of the surface 13 of the aerosol generating device. In this way, the thermal feedback unit 40 is operable to provide a thermal output to a user of the aerosol generating device 10 via the surface 13 of the aerosol generating device 10. The provision of the thermal output is initiated by the controller 24 of the aerosol generating device 10, in that the thermal feedback unit 40 is operable to cause either the first thermal adjustment element 42 or the second thermal adjustment element 44 to provide the thermal output in response to a signal received from the controller 24.

[0060] In the example shown in Figure 1 , the thermal feedback unit 40 is operable to adjust (i.e. increase or decrease) the temperature of a predefined portion 46 of the surface 13 of the aerosol generating device in order to provide the thermal output. A “thermal output” as described herein means an output in the form of a temperature change (i.e. an increased or decreased temperature) at the surface of the device. The temperature change is preferably user-discernible, and the thermal feedback unit 40 may thus be considered part of the user interface 13 of the aerosol generating device, since it may be used to convey information to the user in some circumstances (as discussed in more detail below).

[0061] By providing separate and distinct first and second thermal adjustment elements 42, 44, the thermal feedback unit 40 is able to quickly and reliably change between two different temperatures, so providing a simpler and more reliable thermal output than if only one thermal adjustment element had been provided. As noted above, the thermal feedback unit 40 shown in Figure 1 includes two thermal adjustment elements 42, 44: the first thermal adjustment element 42 and the second thermal adjustment element 44. The first thermal adjustment element 42 is configured to increase the temperature of a first region 48 of the surface 13 of the aerosol generating device, and in particular, is configured to increase the temperature of a first region 48 of the predefined portion 46 of the surface 13. Conversely, the second thermal adjustment element 44 is configured to decrease the temperature of a second region 50 of the surface 13 of the aerosol generating device 10, and in particular, is configured to decrease the temperature of a second region 50 of the predefined portion 46 of the surface 13. The first region 48 is adjacent to the second region 50, and both first and second regions are enclosed within the predefined portion 46, which represents a subset of the entire device surface 13.

[0062] At least one of the first and second regions 48, 50, and in this case the entire predefined portion 46 of the surface 13, comprises a material having a higher thermal conductivity than a different region of the surface of the aerosol generating device. More specifically, the predefined portion 46 of the surface 13 comprises a material having a higher thermal conductivity than a region of the device surface surrounding the predefined portion. The thermal output may thus be transferred more readily through the predefined portion 46 than through the surrounding region of the device surface 13. In the example shown, the first and second regions 48, 50 comprise a metal material, whilst the remainder of the device surface comprises a plastics material.

[0063] A first example 40a of a thermal feedback unit 40 is shown in more detail in Figure 2. In this example, the first thermal adjustment element 42 comprises a first thermoelectric element 52, whilst the second thermal adjustment element 44 comprises a second thermoelectric element 54. In particular, the first thermoelectric element 52 comprises a first Peltier element, and the second thermoelectric element 54 comprises a second Peltier element. A Peltier element is a solid-state active heat pump, which transfers heat from one side of the element (the “cold side”) to the other side of the element (the “hot side”), depending on the direction of a current provided to the element. In the present example, the first Peltier element is oriented with its hot side facing towards the first region 48 of the surface 13, whilst the second Peltier element is oppositely oriented, such that its cold side is facing towards the second region 50 of the surface 13 of the aerosol generating device. Thus the first Peltier element is configured to heat the first region 48 when energised by a current in a first direction and the second Peltier element is configured to cool the second region when energised by a current in the first (i.e. the same) direction.

[0064] A thermal insulator 56 is positioned between the first thermal adjustment element 42 and the second thermal adjustment element 44, in order to improve the thermal isolation of the first and second thermal adjustment elements. The thermal insulator may comprise a solid insulating material, or may comprise an air gap.

[0065] A second example 40b of a thermal feedback unit 40 is shown in Figure 3. In this example, thermal feedback unit 40 includes a first plurality of first thermal adjustment elements 42, and a second plurality of second thermal adjustment elements 44. Specifically, the thermal feedback unit includes two first thermal adjustment elements 42 and two second thermal adjustment elements 44. Each first thermal adjustment element 42 is configured to increase a temperature of a respective first region 48 of the surface of the aerosol generating device. The first plurality of first thermal adjustment elements 42 act cooperatively, in that they all work to increase the temperature of the first regions 48 simultaneously, and by substantially the same amount. Each second thermal adjustment element 44 is configured to decrease a temperature of a respective second region 50 of the surface of the aerosol generating device. The second plurality of second thermal adjustment elements 44 also act cooperatively, in that they all work to decrease the temperature of the second regions 50 simultaneously, and by substantially the same amount. The respective first and second regions 48, 50 are all located within the predefined portion 46 of the device surface 13. Furthermore, the first and second thermal adjustment elements 42, 44 are arranged alternately in one direction, such that each first thermal adjustment element is located adjacent a second thermal adjustment element in a repeating pattern of first, second, first, second, and so on. The thermal adjustment elements 42, 44 are generally elongate in shape, such that the first and second regions 48, 50 are generally strip shaped, in that they have a length that is significantly greater, e.g. more than two times greater, than their width. This may assist in creating the perception by a user that the entirety of the predefined portion 46 is being either heated (by the first plurality of stripshaped first thermal adjustment elements 42) or cooled (by the second plurality of strip-shaped second thermal adjustment elements 44) at any given time. Although Figure 3 shows two first thermal adjustment elements 42 and two second thermal adjustment elements 44, it will be appreciated that any number of first and second thermal adjustment elements may be provided, and that they may have a different shape to that shown.

[0066] A third example 40c of a thermal feedback unit 40 is shown in Figure 4. In this example, thermal feedback unit 40 also includes a first plurality of first thermal adjustment elements 42, and a second plurality of second thermal adjustment elements 44. Specifically, the thermal feedback unit includes two first thermal adjustment elements 42 and two second thermal adjustment elements 44. Each first thermal adjustment element 42 is configured to increase a temperature of a respective first region 48 of the surface of the aerosol generating device. Each second thermal adjustment element 44 is configured to decrease a temperature of a respective second region 50. Like the second example 40b thermal feedback unit 40, the first plurality of first thermal adjustment elements 42 work cooperatively, as do the second plurality of second thermal adjustment elements 44. Unlike the second example 40b thermal feedback unit 40, however, the first and second thermal adjustment elements are arranged alternately in one direction, and also arranged alternately in another direction different to the one direction. Such a chequerboard pattern of alternating first and second thermal adjustment elements 42, 44 ensures an even distribution of first and second thermal adjustment elements within the predefined portion 46 of the device surface 13, and may be extended in the first and second directions to include any number of first and second thermal adjustment elements 42, 44, as shown in the fourth example 40d thermal feedback unit 40 shown in Figure 5. Although Figure 5 shows four first thermal adjustment elements 42 and four second thermal adjustment elements 44, it will be appreciated that any number of first and second thermal adjustment elements may be provided, such that the chequerboard pattern may be extended further as required, as indicated in phantom. It will further be appreciated that the individual thermal adjustment elements 42, 44 may have any shape, as required.

[0067] One or more thermal insulators of the type shown in Figure 2 may optionally be provided in the thermal feedback units shown in Figures 3-5, if required.

[0068] Turning now to Figure 6, a second example of an aerosol generating device 10 is shown. The second example aerosol generating device 10 includes all of the features described above with reference to Figure 1 , and so in the interest of brevity those common features are not described again below. It is noted, however, that a sliding cover 60 (not shown in Figure 1) is visible in Figure 6, where it is illustrated in a closed position, covering the opening 28 into the heating chamber 18.

[0069] The second example aerosol generating device 10 comprises a housing 62, which defines at least a portion of the surface 13 of the aerosol generating device. In this case, the housing 62 defines the surface of a lower portion of the aerosol generating device, with a lid housing 63 defining the surface of an upper portion of the device. A thermal feedback unit 40 according to the second example 40a is included in the aerosol generating device 10 within the housing 62, in thermal communication with an interior surface of the housing 62 such that the thermal output may be provided at a predefined portion 46 of the device surface 13, and in particular, at a predefined portion 46 of an exterior surface of the housing 62 by thermal conduction through the housing. Thus, the first region 48 of the device surface is provided by a first specified portion 64 of the housing 62, and the second region 44 of the device surface is provided by a second specified portion 66 of the housing 62, different to the first. The first and second specified portions 64, 66 are, in this example, indistinguishable from the remainder of the housing 62, so as to provide a sleek and coherent external appearance to the aerosol generating device.

[0070] As shown in Figures 6 and 7, the aerosol generating device has a non-round, and in particular, generally stadium-shaped cross section, such that the aerosol generating device has a narrow face 68 (and specifically, a pair of opposed narrow faces 68) and a wide face 70 (and specifically, a pair of opposed wide faces 70). The thermal feedback unit 40 is located in thermal proximity to one of the narrow faces so as to be operable to provide the thermal output at the narrow face. An aerosol generating device having such a cross section may typically be held in one hand of a user such that the fingers of the user curl around the narrow face. This configuration may make it easier for user to perceive the thermal output because the finger creases of a user may be more perceptive to small temperature changes than, for example, the user’s palm. In the example shown, a thermal coupling medium 72, such as thermal paste or grease, is provided between the thermal feedback unit 40 and the interior surface of the housing 62. Alternatively, the interior surface of the housing may be shaped to conform to the shape of the thermal adjustment elements 42, 44, so as to improve thermal coupling between the housing and the thermal feedback unit.

[0071] Figures 8 and 9 schematically show a cross section through a third example of an aerosol generating device 10, which is similar to the first and second example aerosol generating devices shown in Figures 1 , 6 and 7. The third example aerosol generating device 10 includes all of the features described above with reference to Figure 1 , and so in the interest of brevity those common features are not described again below.

[0072] The third example aerosol generating device 10 includes a heating arrangement 22 configured to supply heat to an aerosol generating substrate in order to generate an aerosol for inhalation by a user of the aerosol generating device, and further includes a fifth example 40e of a thermal feedback unit 40. The fifth example 40e thermal feedback unit 40 includes a first thermal adjustment element 42 that comprises a heat transfer member 74 which can be actuated to form a thermal connection between the heating arrangement and the first region 48. The heat transfer member 74 can thus be used to deliberately conduct heat from the heating arrangement 22 (which in use will grow hot as it is operated to aerosolise a substrate) towards the surface 13 of the device in order to increase the temperature of the first region 48. When it is no longer desired to heat the first region, the heat transfer member 74 can be actuated to release the thermal connection, in order to prevent further active heating of the first region 48.

[0073] In the example shown, the heat transfer member 74 is a thermal bridge that is pivotable or otherwise rotatable between a first position, shown in Figure 8, in which the thermal connection is made, and a second position, shown in Figure 9, in which the thermal connection is released. It will be appreciated that the pivot point 76 may be located at any convenient position on the thermal bridge, and that the second position need not be at a 90 degree rotation from the first position, as shown, so long as the second position is sufficiently removed from the first position so as to break the thermal connection.

[0074] A first thermal adjustment element 42 of the type shown in Figures 8 and 9 may be used in conjunction with a second thermal adjustment element 44 that is operable to provide cooling, such as a thermoelectric element of the type described above.

[0075] In use, the controller 24 included in an aerosol generating device 10 of the types described above is operable to signal the thermal feedback unit 40 to provide a thermal output to a user of the device. The signal is provided by the controller in response to the receipt of one or more control inputs. “Control input” as used herein means any input receivable by the controller 24 of the aerosol generating device. Examples of suitable control inputs in response to which it may be desirable to provide a thermal output include: a detected type of aerosol generating substrate to be heated by the aerosol generating device, a detected temperature of a region of the aerosol generating device, a detected temperature of a region of the user, a detected or received (e.g. from a meteorological service) temperature of the external environment, a user input received by the aerosol generating device, a detected user inhalation. A user input may include an input provided by the user via the user interface 13 of the aerosol generating device, or may include an input provided by the user via a user interface of a connected device, such as a user’s smart phone or computer. The user input may be stored in a memory of the aerosol generating device as a user preference, or may be acted on by the controller at the time that it is received.

[0076] The controller of the aerosol generating device may be operable to select a thermal profile for the thermal output based on one or more of the control inputs. A control input may thus serve a dual function of both triggering the initiation of the thermal output and of governing the manner in which the thermal output is provided. A thermal profile defines the operating parameters for the thermal feedback unit in order to ensure that the thermal output is provided in a predefined and repeatable manner. Examples of first, second and third thermal profiles are shown in Figures 10 and 11 .

[0077] Figure 10 shows two exemplary thermal profiles, a first thermal profile 80, and a second thermal profile 82. In the first thermal profile 80, the thermal feedback unit 40 is controlled to raise the temperature of the predefined portion 46 of the device surface 13 to a set temperature, and then to maintain that set temperature for a set time, in this case the length of a session (typically 2-3 minutes). In the second thermal profile 82, the thermal feedback unit 40 is controlled to lower the temperature of the predefined portion 46 of the device surface 13 to a set temperature, and then to maintain that set temperature for a set time, in this case the length of a session.

[0078] For reference, Figure 10 also illustrates a typical temperature profile 84 which shows how the surface of an aerosol generating device typically changes overtime in the absence of any active temperature control via a thermal feedback unit 40 of the type described herein. It will be seen that in such a typical, uncontrolled, scenario, the temperature of the device surface gradually increases over time as the session progresses, due to leaked heat from the heating arrangement gradually escaping toward the exterior of the device.

[0079] In contrast, according to the first thermal profile 80, the temperature of the surface is raised quickly to a first temperature, that is higher than (or approximately equal to) the maximum surface temperature expected to be achieved by the end of a session during normal use. This profile may give the user a sense of warmth throughout the session that may enhance the user experience. Such a profile could be appropriate when a consumable having a warm flavour, such as cinnamon, is inserted, for example, or when the external temperature or the user’s hands is detected to be cold.

[0080] Similarly, according to the second thermal profile 82, the temperature of the surface is lowered quickly to a second temperature, that is lower than (or approximately equal to) the starting surface temperature of the device. This profile may give the user a sense of freshness throughout the session that may enhance the user experience. Such a profile could be appropriate when a consumable having a cool flavour, such as menthol, is inserted, for example, or when the external temperature or the user’s hands is detected to be warm.

[0081] The aerosol generating device may be configured for use with a plurality of different types of consumable, each of which may comprise a different type of aerosol generating substrate. The controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles according to a type of aerosol generating substrate. For example, the aerosol generating device may comprise an article detection unit for distinguishing between one or more types of consumable, and the controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles when a certain type of consumable is detected. Such an article detection unit may be configured to read an indicator provided on the consumable, which may be a visible indicator such as a barcode, or a concealed indicator, such as an RFID chip. Alternatively, the type of article may be indicated to the controller by the user themselves, via a user input. The aerosol generating device may comprise a temperature sensor (not shown) for measuring a temperature at a certain location in or on the device. For example, a sensor may be provided that is operable to measure the temperature of the predefined portion 46 of the device surface. Alternatively, or additionally, a sensor may be provided that is operable to measure an ambient temperature external to the device. Alternatively, or additionally, a sensor may be provided that is operable to measure a temperature of a region of a user touching the device (e.g. the user’s palm or finger). The controller may be operable to select a specific thermal profile from a plurality of stored thermal profiles with reference to the temperature, and / or the thermal output may be provided relative to the measured temperature (e.g. as a deviation from the measured temperature by a predefined value). Thus, in the exemplary first and second profiles discussed above, the set temperature may be selected to be a predefined amount above (or below) the measured temperature.

[0082] The aerosol generating device may further comprise a puff detector (not shown) operable to detect a user inhalation. In a third example thermal profile 86, shown in Figure 11 , the thermal output may be provided to the user on detection of a user inhalation. For example, a set temperature of one of the first and second regions may be adjusted by a selected amount each time a user inhalation is detected. For example, the thermal output may be provided as a decrease in temperature each time a user inhalation is detected. In the example shown, the thermal output is provided as a temporary decrease in temperature, with the magnitude of the decrease being roughly constant relative to the current (expected or measured) surface temperature of the device. Alternatively, or additionally, the temperature of the thermal output may be selected by the controller in proportion to a detected amount of the user inhalation. For example, the thermal output may be controlled such that a deeper user inhalation is paired with a greater decrease in temperature of the thermal output.

[0083] It will be appreciated that other types of thermal profile may be followed in addition to those illustrated in Figures 10 and 11 . For example, a thermal profile may comprise adjusting a temperature, for example a set temperature of one of the first and second regions, to a selected value for a temporary period (e.g. 1-5 seconds). The thermal output may directly follow a control input, such as insertion of a consumable or activation of the heating arrangement 22. In this way the user may be provided quickly with an increase or decrease in temperature at the surface of the aerosol generating device following the control signal, which may be useful in providing a notification to the user. Alternatively, a thermal profile may comprise adjusting a temperature, for example a set temperature of one of the first and second regions, to a selected value for a temporary period (e.g. 1-5 seconds) at a plurality of discrete times during a usage session, or adjusting the temperature of the first and second regions to a plurality of different temperatures, each for a temporary period, according to a selected pattern. In this way the user sensory experience throughout the session may be modified by the thermal output. Furthermore, a thermal output following a recognisable pattern may be useful in providing a notification to the user.

[0084] The present trend in aerosol generating devices tends towards miniaturisation. In this context, one significant challenge is to ensure an acceptable device surface temperature because the insulation between heating element and device housing may be reduced. The thermal feedback unit may thus be operable to prevent further heating by the first thermal adjustment element(s) once a predefined maximum temperature is reached, and / or to provide cooling via the second thermal adjustment element(s) once a predefined maximum temperature is reached or exceeded, even when this deviates from the selected thermal profile.

[0085] The thermal feedback unit may be controlled to confine the total amount of energy consumed for the thermal output, within a prescribed limit during any single aerosol generating session, so as to preserve battery life.

[0086] The thermal feedback unit described herein seeks to elevate the sensory experience associated with using an aerosol generating device through the integration of touch sensitive capabilities. Specifically, the device is designed to modulate the temperature of its external surfaces, allowing users to experience tactile (and specifically thermal) feedback in addition to the traditional benefits of the product. The temperature modulation may be contingent on several factors, including: the type of consumable detected by the device, user-defined settings or other user inputs, external environmental conditions, such as outdoor temperature, user biometrics, including heart rate and body temperature. The thermal feedback unit thus creates a new dimension for user experience by engaging multiple senses simultaneously, as well as to providing a subtle and unique method of notifying a user about the conditions of their device.

[0087] Although exemplary embodiments have been described in the preceding paragraphs, it should be understood that various modifications may be made to those embodiments without departing from the scope of the appended claims. Thus, the breadth and scope of the claims should not be limited to the above-described exemplary embodiments.

Claims

CLAIMS1. An aerosol generating device (10) comprising: a thermal feedback unit (40) comprising: a first thermal adjustment element (42) configured to adjust a temperature of a surface (13) of the aerosol generating device; and a second thermal adjustment element (44) configured to adjust a temperature of the surface of the aerosol generating device; and a controller (24); wherein the thermal feedback unit (40) is operable to provide a thermal output to a user of the aerosol generating device (10) via the surface (13) of the aerosol generating device in response to a signal from the controller (24); and wherein the first thermal adjustment element (42) is configured only to increase a temperature of a first region (48) of the surface (13) of the aerosol generating device, and the second thermal adjustment element (44) is configured only to decrease a temperature of a second region (50) of the surface (13) of the aerosol generating device, where the first region (48) is different to the second region (50).

2. The aerosol generating device of claim 1 , wherein the first and second thermal adjustment elements (42, 44) are configured such that they do not operate at the same time.

3. The aerosol generating device of claim 1 or claim 2, wherein the first region (48) is adjacent the second region (50).

4. The aerosol generating device of any preceding claim, wherein the thermal feedback unit (40) comprises a first plurality of first thermal adjustment elements (42), and a second plurality of second thermal adjustment elements (44), wherein each first thermal adjustment element (42) is configured only to increase a temperature of a respective first region (48) of the surface (13) of the aerosol generating device, and each second thermal adjustment element (44) is configured only to decrease a temperature of a respective second region (50) of the surface (13) of the aerosol generating device.

5. The aerosol generating device of claim 4, wherein the thermal feedback unit (40) is configured to operate the first plurality of first thermal adjustment elements (42) simultaneously and in the same manner, such that the first plurality of thermal adjustment elements (42) operate together, and wherein the thermal feedback unit (40) is configured to operate the second plurality of second thermal adjustment elements (44) simultaneously and in the same manner, such that the second plurality of thermal adjustment elements (44) operate together.

6. The aerosol generating device of claim 4 or claim 5, wherein the first and second thermal adjustment elements (42, 44) are arranged alternately in one direction.

7. The aerosol generating device of claim 6, wherein the first and second thermal adjustment elements (42, 44) are also arranged alternately in another direction different to the one direction.

8. The aerosol generating device of claim 7, wherein the first and second thermal adjustment elements (42, 44) are arranged one between the other in a first direction and also in a second direction perpendicular to the first, so as to be arranged in a chequerboard pattern.

9. The aerosol generating device of any preceding claim, further comprising a thermal insulator (56) positioned between a first thermal adjustment element (42) and a second thermal element (44).

10. The aerosol generating device of any preceding claim, wherein at least one of the first and second regions (48, 50) comprises a material having a higher thermal conductivity than a different region of the surface (13) of the aerosol generating device.

11. The aerosol generating device of any preceding claim, further comprising a housing (62, 63), wherein the (or each) first region (48) comprises a first specified portion (64) of the housing (62, 63) and the (or each) second region (50) comprises a second specified portion (66) of the housing (62, 63) different to the first.

12. The aerosol generating device of any preceding claim, wherein the aerosol generating device is non-circular in cross section such that the aerosol generating device has a narrow face (68) and a wide face (70), wherein the thermal feedback unit (40) is operable to provide the thermal output at the narrow face (68).

13. The aerosol generating device of any preceding claim, further comprising a heating arrangement (22) configured to supply heat to an aerosol generating substrate in order to generate an aerosol for inhalation by a user of the aerosol generating device.

14. The aerosol generating device of any preceding claim, wherein the controller (22) is operable to signal the thermal feedback unit (40) to provide the thermal output to the user in response to a control input.

15. The aerosol generating device of claim 14, wherein the control input comprises one or more of: a type of aerosol generating substrate to be heated by the aerosol generating device, a detected temperature of a region of the aerosol generating device, a detected temperature of a region of the user, a temperature of the external environment, a user input received by the aerosol generating device, a detected user inhalation, an indication of a user preference.

16. The aerosol generating device of claim 14 or claim 15, wherein the controller (22) is operable to select a thermal profile (80, 82, 86) for the thermal output based on the control input.

17. The aerosol generating device of claim 16, wherein the thermal profile (80, 82, 86) comprises one of: adjusting a temperature to a selected value, adjusting a temperature to a selected value and then maintaining the temperature at that predefined value until an end of a usage session, adjusting a temperature to a selected value at a plurality of discrete times during a usage session, adjusting a temperature according to a selected pattern.

18. The aerosol generating device of any preceding claim, further comprising a puff detector operable to detect a user inhalation, wherein the thermal output is provided to the user on detection of a user inhalation, and wherein a temperature of the thermal output is selected by the controller in proportion to a detected amount of the user inhalation.

19. The aerosol generating device of any preceding claim, wherein at least one of the first and second thermal adjustment elements (42, 44) comprises a thermoelectric element (52, 54).

20. The aerosol generating device of claim 19, wherein the (or each) first thermal adjustment element (42) comprises a first thermoelectric element (52) and the (or each) second thermal adjustment element (44) comprises a second thermoelectric element (54), wherein a hot side of the (or each) first thermoelectric element (52) faces towards the (or each) first region (48) of the surface (13) and a cold side of the (or each) second thermoelectric element faces towards the (or each) second region (50) of the surface (13).

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