Aerosol Generator

Abstract

An aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol during a use session is disclosed. The aerosol generating device comprises control electronics and a substantially linear first lighting array and a substantially linear second lighting array, each of the first and second lighting arrays extending over a length between a first end and a second end of the respective lighting array. The control electronics is coupled to the first and second lighting arrays and configured to operate either or both of the first and second lighting arrays to generate a predetermined light emission indicative of at least one of i) a state of the aerosol generating device, and ii) a progression of an operational stage of the aerosol generating device.

Description

[Technical field]

[0001] The present disclosure relates to an aerosol generating device in which data regarding the progress of an operational stage of the device is visually communicated to a user of the device. [Background technology]

[0002] Aerosol-generating devices configured to generate an aerosol from an aerosol-forming substrate, such as a tobacco-containing substrate, are known in the art. Typically, the inhalable aerosol is generated by heat transfer from a heat source to a physically separate aerosol-forming substrate or material, which may be located within, around, or downstream of the heat source. The aerosol-forming substrate may be a liquid substrate contained in a reservoir. The aerosol-forming substrate may also be a solid substrate. The aerosol-forming substrate may be part of a separate aerosol-generating article component configured to engage with the aerosol-generating device to form an aerosol. Volatile compounds are released from the aerosol-forming substrate by heat transfer from the heat source during consumption and are entrained in the air released through the aerosol-generating article. The released compounds condense upon cooling to form the aerosol that is inhaled by the consumer.

[0003] During use of an aerosol generating device, one or more parameters of the device may change. It is desirable to provide an aerosol generating device that can efficiently communicate data regarding the status of the device to a user.

[0004] As used herein, the term "aerosol-generating device" is used to describe a device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol. The aerosol-generating device is preferably a smoking device that interacts with an aerosol-forming substrate of an aerosol-generating article to generate an aerosol that is inhalable directly through the user's mouth into the user's lungs. The aerosol-generating device may be a holder for a smoking article. The aerosol-generating article is preferably a smoking article that generates an aerosol that is inhalable directly through the user's mouth into the user's lungs. More preferably, the aerosol-generating article is a smoking article that generates a nicotine-containing aerosol that is inhalable directly through the user's mouth into the user's lungs.

[0005] As used herein, the term "aerosol-forming substrate" refers to a substrate composed of or including an aerosol-forming material capable of releasing a volatile compound upon heating to generate an aerosol. Summary of the Invention

[0006] According to an aspect of the invention, there is provided an aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol during a session of use. The aerosol generating device comprises control electronics and a substantially linear first lighting array and a substantially linear second lighting array, each of the first and second lighting arrays extending over a length between a first end and a second end of the respective lighting array. The control electronics is coupled to the first and second lighting arrays and configured to operate either or both of the first and second lighting arrays to generate a predetermined light emission indicative of at least one of i) a state of the aerosol generating device, and ii) a progression through an operational stage of the aerosol generating device.

[0007] As used herein, the term "light" refers to emissions of electromagnetic radiation in the visible range of the electromagnetic spectrum, which is generally understood to include wavelengths ranging from about 380 nanometers to about 750 nanometers.

[0008] As used herein, the term "predetermined light emission" refers to a light emission that is characterized in terms of one or more parameters of the light emission. By way of example, the one or more parameters may include any of the following: a luminance level of the light emission, a spatial variation in the luminance level of the light emission in one or both of the first and second lighting arrays, a color of the light emission, a spatial variation in the color of the light emission in one or both of the first and second lighting arrays, a percentage of one or both of the first and second lighting arrays that are activated to generate the light emission. The one or more parameters may also include a variation over time of any of the parameters described in the preceding sentence.

[0009] The operational phase may be any phase of operation of the aerosol generating device. By way of example and not limitation, the operational phase may be a pre-heat phase or a use session of operation.

[0010] The pre-heat stage of operation is a stage of operation of the aerosol generating device during which the temperature of the electrical heating arrangement of the aerosol generating device is increased to a predetermined target temperature.

[0011] A use session is a finite use session, i.e., a use session that has a beginning and an end. The duration of a use session, as measured in time, may be affected by use during the use session. The duration of a use session may have a maximum duration determined by a maximum time from the start of a use session. The duration of a use session may be less than the maximum time if one or more monitored parameters reach a predefined threshold before the maximum time from the start of a use session. As an example, the one or more monitored parameters may include one or more of i) a cumulative number of puffs in a series of puffs drawn by a user after the start of a use session, and ii) a cumulative volume of aerosol emitted from an aerosol-forming substrate after the start of a use session.

[0012] As described above, coupling the control electronics to the first and second lighting arrays allows the lighting arrays to provide data to a user in a visual format indicative of the device's status or the progression of the device's operational stages. The use of two lighting arrays may allow each of the first and second lighting arrays to communicate different data to the user. The linear nature of the first and second lighting arrays is particularly suited to tracking the progression of the aerosol generating device's operational stages by corresponding changes in the predetermined light emission. The change in the predetermined light emission with the progression of the operational stages may take the form of a change in one or more of the brightness level of the light emission, the color or distribution of colors forming the light emission, and the proportion of one or both of the first and second lighting arrays that are activated to generate the light emission.

[0013] The control electronics may preferably be configured to operate either or both of the first and second lighting arrays at two or more brightness levels to control the brightness of the predetermined light emission. In this manner, the brightness level of the predetermined light emission may provide a user with an indication of the status of the aerosol generating device, or of progression through an operational stage. As an example, if the predetermined light emission is indicative of a pre-heat stage of operation or progression through a use session, the brightness level of one or both of the first and second lighting arrays may increase or decrease in generating the predetermined light emission as the pre-heat stage or progression through a use session progresses.

[0014] The control electronics may be configured to operate either or both of the first and second lighting arrays in two or more color states to control the color of the predetermined light emission. In this manner, the color of the predetermined light emission may provide a user with an indication of the status of the aerosol generating device, or its progression through a stage of operation. The "color" of the predetermined light emission may be a spatial variation of color in one or both of the first and second lighting arrays.

[0015] The control electronics may be configured to activate either or both of the first and second lighting arrays to vary the predetermined light emission over time. Variation of the predetermined light emission over time may be particularly useful to enable the control electronics to adjust the predetermined light emission to track or indicate changes in the state of the aerosol generating device or its progression through stages of operation. The variation of the predetermined light emission over time may be a change in one or more of the brightness of the predetermined light emission, the color of the predetermined light emission, and the percentage of one or both of the lighting arrays that are activated to generate the predetermined light emission.

[0016] The control electronics may be configured to activate either or both of the first and second illumination arrays to vary the predetermined light emission over time to indicate a progression of operational stages of the aerosol generating device. Conveniently, the progression of operational stages may be a progression of a use session. Alternatively, the progression of operational stages may be a progression of a pre-heating stage of operation of an electrical heating arrangement used to heat the aerosol-forming substrate.

[0017] The control electronics may be configured to operate either or both of the first and second lighting arrays to vary the activation length of each lighting array over time. Varying the activation length of each lighting array changes the proportion of each lighting array that contributes to generating a given light emission. The control electronics may be configured to increase or decrease the activation length of each lighting array while the aerosol generating device remains in a given state or as the aerosol generating device progresses through an operational phase. This may be particularly beneficial where the operational phase is a pre-heat phase or a use session of operation of the electrical heating arrangement, where the increase or decrease in activation length effectively conveys data to the user regarding the progression through the pre-heat phase or use session.

[0018] The control electronics may be configured to vary the predetermined light emission over time in one or more of brightness and color. An increase or decrease in brightness or color over time may be particularly useful in communicating to a user changes that have occurred in the temperature of the electrical heating arrangement of the aerosol generating device. As an example, as the temperature of the electrical heating arrangement increases towards a predetermined target temperature, the predetermined light emission may be adjusted from a first state consisting of or including a color towards the blue end of the electromagnetic spectrum to a second state consisting of or including a color towards the red end of the electromagnetic spectrum.

[0019] The control electronics may be configured to vary the predetermined light emission over time by one or more of activating, deactivating, and reactivating different portions of either or both of the first and second lighting arrays over time. Varying over time which portion or portions of either or both of the first and second lighting arrays are activated may facilitate efficiently communicating data to a user that there has been a change in the state of the aerosol generation device, or a change in the progression of an operational stage of the aerosol generation device.

[0020] Each of the first and second lighting arrays preferably includes a plurality of light emitting units distributed between the first and second ends of the respective lighting array. Thus, each or different of the light emitting units may contribute to a given light emission according to which light emitting units are activated by the control electronics at a given moment. All or only a portion of the light emitting units may be used to generate a given light emission at a given moment. The use of light emitting units in the form of light emitting diodes (LEDs) is preferred due to the high energy efficiency of LEDs. It is preferred that the aerosol generating device is handheld and sized to provide portability, including a power source. The power source may conveniently be in the form of a rechargeable battery. In this context, the energy efficiency associated with LEDs makes them particularly suitable for use in such handheld portable aerosol generating devices having their own power source. However, alternatively, the light emitting units may instead consist of one or more liquid crystal displays, or any other electrically powered light source whose energy and size requirements are suitable for use in aerosol generating devices.

[0021] The aerosol generating device advantageously further comprises one or more waveguides configured to direct light generated by one or more of the plurality of light emitting units to one or more viewing windows for viewing the predetermined light emission by a user. As used herein, the term "waveguide" refers to a structure adapted to guide electromagnetic waves of light. The waveguides may advantageously be in the form of one or more optical fibres or light pipes. Each of the light emitting units is advantageously associated with a corresponding waveguide such that light emitted from each light emitting unit is transmitted to the one or more viewing windows via the corresponding waveguide.

[0022] Preferably, each of the plurality of light emitting units may include a light emitting diode, and the control electronics may include a light emitting diode control driver and a separate microcontroller. The control driver may be configured to control an electrical supply from a power source to one or more of the plurality of light emitting diodes of either or both of the first and second lighting arrays under the control of the microcontroller to generate a predetermined light emission. The control driver may be configured to control one or both of a voltage level or a current level of the electrical supply.

[0023] The plurality of light emitting diodes of each of the first and second lighting arrays may additionally include a first set of one or more light emitting diodes configured to emit light of a first color and a second set of one or more light emitting diodes configured to emit light of a second color. The light emitting diode control driver may be configured to activate one or more of the light emitting diodes from only the first set of either or both of the first and second lighting arrays, or from only the second set of either or both of the first and second lighting arrays, or from both the first and second sets of either or both of the first and second lighting arrays to control the color of the predetermined light emission.

[0024] The light-emitting diode control driver may advantageously be configured to control the electrical supply from the power source to one or more of the plurality of light-emitting diodes of either or both of the first and second lighting arrays by a type of pulse width modulation having a predetermined resolution to control the brightness of the predetermined light emission, the predetermined resolution defining two or more brightness levels. As an example, the resolution of the type of pulse width modulation may be 8 bits (having 256 levels), 10 bits (having 1024 levels), or 12 bits (having 4096 levels). The higher the predetermined resolution, the greater the number of discrete quiescent brightness levels of light that can be generated by each of the plurality of light-emitting diodes. In this way, the precision or level of detail of the data conveyed to the user by different brightness levels can be controlled by the predetermined resolution selected for the light-emitting diode control driver.

[0025] Preferably, the length of the first lighting array may be the same as the length of the second lighting array.

[0026] Preferably, the first lighting array and the second lighting array may be laterally spaced from each other and parallel to each other.

[0027] Advantageously, the first and second lighting arrays are each the same length and laterally spaced from one another so as to be parallel and aligned with one another, and the first and second ends of the first lighting array are aligned with the first and second ends of the second lighting array.

[0028] Preferably, the predetermined light emission is one or more of a use session light emission, a low energy light emission, a thermal profile light emission, a pause light emission, a state change light emission, a progression light emission, and a pre-heating light emission. By "use session light emission" is meant a light emission indicative of a power source of the aerosol generating device containing sufficient energy to complete a predetermined number of use sessions. By "low energy light emission" is meant a light emission indicative of a power source of the aerosol generating device containing energy below a predetermined threshold level of energy. By "thermal profile light emission" is meant a light emission indicative of a selection of one of at least two predetermined thermal profiles of the electrical heating arrangement of the aerosol generating device. By "pause light emission" is meant a light emission indicative of an aerosol generating device being in a pause mode. By "state change light emission" is meant a light emission indicative of a change in the operating state of the aerosol generating device. By "progression light emission" is meant a light emission indicative of a progression through a use session. By "pre-heating light emission" is meant a light emission indicative of a progression through a pre-heating stage of operation of the electrical heating arrangement of the aerosol generating device. Examples of these different forms of "light emission" are outlined in the following paragraphs.

[0029] The above paragraphs describe the arrangement of the first and second lighting arrays, but do not exclude the provision of additional lighting arrays. In particular, advantageously, the aerosol generating device may further comprise a substantially linear third lighting array located between and parallel to each of the first and second lighting arrays, the control electronics being configured to operate the third lighting array alone or in addition to either or both of the first and second lighting arrays to generate a predetermined light emission. The addition of a third lighting array in line with the first and second lighting arrays further increases the complexity and accuracy of the data that can be communicated to the user regarding the status and operational stage progression of the aerosol generating device.

[0030] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The control electronics may be configured to determine a level of energy contained within the power source and to compare the determined level of energy to first and second predetermined energy thresholds. The first predetermined energy threshold may correspond to the power source containing sufficient energy to complete a single use session. The second predetermined energy threshold may correspond to the power source containing sufficient energy to complete two or more use sessions. The control electronics may also be configured to operate either or both of the first and second lighting arrays to generate a single use session light emission in response to a first condition in which the determined level of energy is sufficient to complete a single use session, and to operate either or both of the first and second lighting arrays to generate multiple use session light emissions in response to a second condition in which the determined level of energy is sufficient to complete two or more use sessions. The single use session light emission and the multiple use session light emission are distinct from one another. The single use session light emission indicates a first condition and the multiple use session light emission indicates a second condition. In this manner, a visual indication may be provided to a user as to whether the power source has sufficient energy to complete either a single use session or multiple use sessions. As an example, the power source may be selected to have an energy capacity sufficient to complete two usage sessions before requiring replacement or recharging, and a plurality of usage sessions is two usage sessions, however, the energy capacity of the power source may be selected to allow for the completion of more than two usage sessions before requiring replacement or recharging.

[0031] The control electronics may be configured to activate a greater proportion of either or both of the first and second lighting arrays to generate a multiple use session light emission than to generate a single use session light emission.

[0032] The control electronics may be configured to, in response to a first condition, activate all or a portion of only the first lighting array to generate a single use session light emission, and in response to a second condition, activate all or a portion of both the first lighting array and the second lighting array to generate a multiple use session light emission. Conveniently, the control electronics may be configured to activate 90%-100% of the length of the first lighting array to generate the single use session light emission, and activate 90%-100% of the length of both the first lighting array and the second lighting array to generate a multiple use session light emission.

[0033] The control electronics may be configured to operate either or both of the first and second lighting arrays such that the single use session light emission and the multiple use session light emission differ from each other in one or more of brightness and color. Conveniently, the control electronics may be configured to operate either or both of the first and second lighting arrays such that the single use session light emission has a first predetermined brightness and the multiple use session light emission has a second predetermined brightness, the second predetermined brightness being greater than the first predetermined brightness.

[0034] The aerosol generating device may advantageously further comprise a power source coupled to the control electronics. The control electronics may be configured to determine a level of energy contained in the power source, compare the determined level of energy to a predetermined threshold level of energy, and in response to the determined level of energy being equal to or less than the predetermined threshold level of energy, activate either or both of the first and second lighting arrays to generate a low energy light emission. The low energy light emission indicates that the determined level of energy is equal to or less than the predetermined threshold level of energy. In this manner, a visual indication may be provided to the user that the power source has insufficient energy to complete a full usage session. If the power source is a rechargeable power source, the low energy light emission may provide a visual indication to the user that the power source requires recharging.

[0035] The predetermined threshold level of energy is preferably less than or equal to 20% of the predetermined energy capacity of the power source.

[0036] The control electronics may be configured to operate either or both of the first and second lighting arrays such that the low energy light emissions have a predetermined color.

[0037] The control electronics may be configured to activate a small percentage of either or both of the first and second lighting arrays to generate low energy light radiation. Preferably, the small percentage forms less than 15%, or preferably less than 10%, or preferably less than 5% of a length of either or both of the first and second lighting arrays. The small percentage may be located at one of the first ends or the second ends of either or both of the first and second lighting arrays.

[0038] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The control electronics may be configured to receive a selection input selecting one of at least a first and a second predefined thermal profile. Each of the first and second predefined thermal profiles may define a heating profile for heating the aerosol-forming substrate by the electric heating arrangement over a use session. The first and second predefined thermal profiles are different from each other. The control electronics may also be configured to control the supply of energy from the power source to the electric heating arrangement to heat the aerosol-forming substrate according to the selected thermal profile, and to activate either or both of the first and second illumination arrays to generate a first thermal profile light radiation in response to the selection of the first predefined thermal profile, and to activate either or both of the first and second illumination arrays to generate a second thermal profile light radiation in response to the selection of the second predefined thermal profile. The first thermal profile light radiation is indicative of the selection of the first predefined thermal profile. The second thermal profile light radiation is indicative of the selection of the second predefined thermal profile. In this way, a visual indication can be provided to the user as to which of the predetermined thermal profiles has been selected for heating the aerosol-forming substrate.

[0039] The second predetermined thermal profile may have a higher intensity than the first predetermined thermal profile, the second predetermined thermal profile being advantageously associated with a greater amount of energy being delivered from the power source to the electric heating arrangement over a session of use than for the first predetermined thermal profile.

[0040] The aerosol generating device may comprise a user interface operable by a user to select between the first and second predetermined thermal profiles, the user interface preferably comprising a button or a motion sensor.

[0041] The control electronics may be configured to generate a selection input in response to a user selecting between the first and second predetermined thermal profiles via the user interface.

[0042] The control electronics may be configured to operate a first proportion of either or both of the first and second lighting arrays to generate a first thermal profile light radiation in response to a selection of a first predetermined thermal profile, and to operate a second proportion of either or both of the first and second lighting arrays to generate a second thermal profile light radiation in response to a selection of a second predetermined thermal profile. The second proportion may be greater than the first proportion. Preferably, the second proportion defines a greater proportion of a combined length of the first and second lighting arrays than the first proportion.

[0043] The first and second lighting arrays may collectively include a plurality of lighting elements, and the control electronics may also be configured to activate a greater number of the lighting elements to generate the second thermal profile light radiation than to generate the first thermal profile light radiation.

[0044] The control electronics may be configured to activate all or a portion of only the first lighting array to generate the first thermal profile light radiation and to activate all or a portion of only the second lighting array to generate the second thermal profile light radiation. Preferably, the control electronics may be configured to activate a first percentage of the length of the first lighting array to generate the first thermal profile light radiation and to activate a second percentage of the length of the second lighting array to generate the second thermal profile light radiation. The second percentage value may be greater than the first percentage value.

[0045] The control electronics may be configured to operate either or both of the first and second lighting arrays such that the first and second thermal profile light radiation differ from each other in one or more of brightness and color. Preferably, the control electronics may be configured to operate either or both of the first and second lighting arrays such that the first thermal profile light radiation has a first predetermined color and the second thermal profile light radiation has a second predetermined color. A dominant wavelength of the second thermal profile light radiation may be greater in size than a dominant wavelength of the first thermal profile light radiation.

[0046] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The control electronics may be configured to control the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate to a first temperature level in the aerosol emission mode, to control the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate to a second temperature level less than the first temperature level in the pause mode, and to activate either or both of the first and second lighting arrays to generate a pause light emission in response to the pause signal. The pause light emission indicates that the aerosol generating device is in the pause mode. In this way, a visual indication may be provided to a user that the aerosol generating device is in the pause mode.

[0047] The aerosol generating device may include a motion sensor for detecting movement of the aerosol generating device, the motion sensor being coupled to the control electronics, the control electronics being configured to use the detected movement to trigger a pause signal.

[0048] The aerosol generating device may include a motion sensor for detecting a lack of movement of the aerosol generating device, the motion sensor being coupled to the control electronics. The control electronics may be configured to use the detected lack of movement to trigger a pause signal. The lack of movement of the aerosol generating device is preferably detected by an absence of movement of the device for a predetermined time, or an absence of movement above a certain magnitude for a predetermined time.

[0049] The aerosol generating device may further comprise a user interface and / or a puff detection mechanism for detecting a puff at the device. The control electronics may be configured to trigger a pause signal in response to detecting an absence of user interaction with the user interface and / or the puff detection mechanism for a predetermined time. The control electronics may preferably be configured to use the detected movement to trigger the pause signal when the detected movement corresponds to a predetermined movement.

[0050] The aerosol generating device may comprise an orientation sensor for detecting an orientation of the aerosol generating device, the orientation sensor being coupled to the control electronics. The control electronics may be configured to use the detected orientation, or the absence of a change in the detected orientation for a predetermined time, to trigger a pause signal. Preferably, the control electronics may be configured to use the detected orientation to trigger a pause signal when the detected orientation corresponds to a predetermined orientation.

[0051] The aerosol generating device may further comprise a user interface actuatable by a user to initiate the pause mode, the user interface preferably comprising a button. The control electronics may preferably be configured to generate a pause signal in response to a user initiating the pause mode via the user interface or in response to detecting an absence of user interaction with the user interface after a predetermined length of time.

[0052] The control electronics may be configured to activate a portion of each of the first and second lighting arrays to generate the suspended light emission. The first and second lighting arrays may be disposed relative to one another such that the respective portions of the first and second lighting arrays are parallel to one another. The respective portions of the first and second lighting arrays may each have substantially the same length. The control electronics may preferably be configured to sequentially activate and deactivate the respective portions of the first and second lighting arrays to generate the suspended light emission. The control electronics may be configured to activate and deactivate the respective portions of the first and second lighting arrays out of phase with one another to generate the suspended light emission.

[0053] The control electronics may be configured to activate respective portions of the first and second lighting arrays to vary over time in at least one of brightness or wavelength to vary the brightness or color of the suspended light emission over time.

[0054] The control electronics may be configured to activate all or a portion of each of the first and second lighting arrays to generate a pause light emission such that a central portion of each of the first and second lighting arrays has a greater brightness than a remaining portion of the respective lighting array. Preferably, the control electronics may be configured to activate all or a portion of each of the first and second lighting arrays to generate a pause light emission such that the brightness of each of the first and second lighting arrays progressively decreases when moving from the central portion to the first and second ends of the respective lighting arrays.

[0055] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The control electronics may be configured to receive an input to change an operational state of the aerosol generating device, control the supply of energy from the power source to change the operational state, and in response to the input, activate either or both of the first and second lighting arrays to generate a state change light emission. The state change light emission may indicate receipt of the input to change the operational state. In this manner, a visual indication of the change in operational state of the aerosol generating device may be provided to a user.

[0056] The change in operating state may include activation of the device from an off mode or reactivation of the device from a pause mode. Preferably, reactivation of the device may correspond to the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate at a first temperature level in the aerosol-emission mode. Furthermore, the pause mode may correspond to the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate at a second temperature level that is less than the first temperature level.

[0057] The control electronics may be configured to progressively activate each of the first and second lighting arrays over a predetermined period of time to progressively increase an activation length of each of the first and second lighting arrays over a predetermined period of time for the state-changing light emission.

[0058] The control electronics may be configured to activate all or a portion of each of the first and second lighting arrays to progressively increase brightness over a predetermined period of time for the state-changing light emission. Preferably, the control electronics may be configured to activate all or a portion of each of the first and second lighting arrays such that at the start of the predetermined period, the brightness of the activated portions of each of the first and second lighting arrays progressively decreases with distance away from the center of the activated portions of the respective lighting arrays towards the first and second ends. The brightness may be progressively increased over the predetermined period such that at the end of the predetermined period, the activated portions of each of the first and second lighting arrays have a uniform brightness over the length of the activated portions of the respective lighting arrays.

[0059] The control electronics may be configured to operate all or a portion of each of the first and second lighting arrays such that the brightness of the activated portion of each of the first and second given lighting arrays is symmetric about a center of the activated portion of the respective lighting array over a predetermined period of time.

[0060] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The control electronics may be configured to control the supply of energy from the power source to the electric heating arrangement over a use session to heat the aerosol-forming substrate, to determine progression through the use session by reference to a parameter indicative of progression through the use session, and to operate either or both of the first and second lighting arrays to generate a progressing light radiation that varies as a function of progression through the use session such that the progressing light radiation is indicative of progression through the use session. In this way, a visual indication of progression through the use session may be provided to the user.

[0061] The parameters indicative of progress through a use session may include one or more of the cumulative time elapsed since the start of the use session, the cumulative number of puffs in a series of puffs drawn by the user since the start of the use session, and the cumulative volume of aerosol emitted from the aerosol-forming substrate since the start of the use session.

[0062] The control electronics may be configured to reduce or terminate the supply of energy from the power source to the electric heating arrangement to complete the use session when the cumulative time elapsed since the start of the use session reaches a predetermined maximum duration.

[0063] The control electronics may be configured to first reduce or terminate the supply of energy from the power source to the electric heating arrangement to complete the use session when i) the cumulative time elapsed since the start of the use session reaches a predetermined maximum duration, and ii) the cumulative number of puffs reaches a predetermined maximum number of puffs.

[0064] The control electronics may be configured to first reduce or terminate the supply of energy from the power source to the electric heating arrangement to complete the use session when i) the cumulative time elapsed since the start of the use session reaches a predetermined maximum duration, and ii) the cumulative volume of the aerosol reaches a predetermined volume limit.

[0065] The control electronics may be configured to activate all or a majority of the first lighting array at the start of a first use session and progressively deactivate the first lighting array to progressively reduce the activation length of the first lighting array as the first use session progresses. The control electronics may be further configured to activate all or a majority of the second lighting array at the start of a second use session and progressively deactivate the second lighting array to progressively reduce the activation length of the second lighting array as the second use session progresses. Conveniently, the control electronics may be configured to prevent light from being emitted from the first lighting array at the completion of the first use session and to prevent light from being emitted from the second lighting array at the completion of the second use session.

[0066] The control electronics may be configured to maintain the second lighting array in a deactivated state over a first use session and to maintain the first lighting array in a deactivated state over a second use session.

[0067] The first and second lighting arrays may be disposed parallel to one another. The control electronics may be configured to activate all or a majority of both the first and second lighting arrays at the start of a use session. The control electronics may be further configured to progressively shut down the first and second lighting arrays in sync with one another such that an activation length of each of the first and second lighting arrays progressively decreases as the use session progresses, such that the respective activation lengths of the first and second lighting arrays remain equal during the use session.

[0068] The first and second lighting arrays may be arranged parallel to one another in a collective arrangement, the collective arrangement of the first and second lighting arrays having a length and a width. The control electronics may be configured to activate all or a majority of both the first and second lighting arrays at the start of a use session. The control electronics may be further configured to progressively stall the first and second lighting arrays to meander along the length across the width of the collective arrangement to progressively decrease the activation length of each of the first and second lighting arrays as the use session progresses.

[0069] The aerosol generating device may further comprise a substantially linear third lighting array located between and parallel to each of the first and second lighting arrays. The control electronics may be configured to activate all or a majority of the third lighting array at the start of a use session. The control electronics may further be configured to progressively deactivate the third lighting array to progressively reduce the activation length of the third lighting array as the use session progresses. The control electronics may preferably be configured such that no light is emitted from the third lighting array upon completion of the use session. The control electronics may preferably be configured to maintain the first and second lighting arrays in a deactivated state throughout the use session.

[0070] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The aerosol generating device may be configured to receive an aerosol-generating article comprising an aerosol-forming substrate. The control electronics may be configured to detect receipt of the aerosol-generating article by the aerosol generating device, control the supply of energy from the power source to the electrical heating arrangement to activate a pre-heating stage in which the electrical heating arrangement is heated to a predetermined target temperature, and activate either or both of the first and second lighting arrays to generate a pre-heating light emission. The pre-heating light emission may vary in response to progression through the pre-heating stage to indicate progression through the pre-heating stage. In this way, a visual indication of progression through the pre-heating stage may be provided to a user.

[0071] The aerosol generating device may comprise a cavity for receiving an aerosol-generating article. The aerosol-generating article may comprise an inductively heatable susceptor. The electric heating arrangement may include an induction heating arrangement coupled to a power source and configured to generate an alternating magnetic field within the cavity to inductively heat the susceptor of the aerosol-generating article when the aerosol-generating article is received within the cavity. The control circuit may be configured to generate probe power pulses to intermittently power the induction heating arrangement and to detect a change in at least one characteristic of the induction heating arrangement due to the presence of the susceptor when the aerosol-generating article is received within the cavity, thereby enabling detection of receipt of the aerosol-generating article within the cavity. Preferably, the at least one characteristic may be an equivalent resistance of the induction heating arrangement or an inductance of the induction heating arrangement.

[0072] The control electronics may be configured to operate the first and second lighting arrays such that different portions of each of the first and second lighting arrays vary in brightness over time and relative to each other, and such that the brightness of each of the first and second lighting arrays increases progressively over the pre-heat phase.

[0073] The control electronics may be configured to operate the first and second illumination arrays such that a dominant wavelength of the predetermined light emission is progressively increased over the pre-heat stage.

[0074] The first and second lighting arrays may be disposed parallel to one another, and the control electronics are configured to operate the first and second lighting arrays in synchronism with one another to progressively increase an operating length of each of the first and second lighting arrays as one progresses through the pre-heating stage, such that the respective operating lengths of the first and second lighting arrays remain equal during a usage session.

[0075] The first and second lighting arrays may be arranged parallel to one another in a grouped arrangement, the grouped arrangement having a length and a width, and the control electronics may be configured to operate the first and second lighting arrays in a serpentine manner across and along the width of the grouped arrangement to progressively increase the operational length of each of the first and second lighting arrays as they progress through the pre-heating stage.

[0076] The control electronics may be configured to operate the first and second lighting arrays during or upon completion of the preheat phase such that the brightness of the respective operating lengths of the first and second lighting arrays increases progressively with increasing distance between the first and second opposing ends of the respective operating lengths.

[0077] The control electronics may be configured to operate the first and second lighting arrays such that during or upon completion of the preheat stage, a dominant wavelength of the preheat light radiation increases progressively with distance between the first and second opposing ends of the respective operating lengths of the first and second lighting arrays. Preferably, the dominant wavelength may be in the range of 380 to 750 nanometers such that during or upon completion of the preheat stage, the first opposing ends define a blue color of the preheat light radiation and the second opposing ends define a red color of the preheat light radiation.

[0078] The control electronics may be configured such that both the first and second lighting arrays have a uniform brightness along the length of their respective lighting arrays upon completion of the pre-heating stage.

[0079] The aerosol-forming substrate is preferably a solid aerosol-forming substrate. However, the aerosol-forming substrate may comprise both solid and liquid components. Alternatively, the aerosol-forming substrate may be a liquid aerosol-forming substrate.

[0080] Preferably the aerosol-forming substrate comprises nicotine. More preferably the aerosol-forming substrate comprises tobacco. Alternatively, or additionally, the aerosol-forming substrate may comprise a non-tobacco-containing aerosol-forming material.

[0081] Where the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate may comprise, for example, one or more of powders, granules, pellets, shreds, threads, strips, or sheets containing one or more of herb leaves, tobacco leaves, tobacco stems, expanded tobacco, and homogenized tobacco.

[0082] Optionally, the solid aerosol-forming substrate may contain tobacco or non-tobacco volatile flavour compounds, which are released upon heating of the solid aerosol-forming substrate. The solid aerosol-forming substrate may also contain one or more capsules, e.g., containing additional tobacco or non-tobacco volatile flavour compounds, which may melt during heating of the solid aerosol-forming substrate.

[0083] Optionally, the solid aerosol-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may take the form of a powder, granules, pellets, pieces, threads, strips, or sheets. The solid aerosol-forming substrate may be deposited on the surface of the carrier, for example in the form of a sheet, foam, gel, or slurry. The solid aerosol-forming substrate may be deposited on the entire surface of the carrier, or alternatively, in a pattern to provide a non-uniform flavor delivery during use.

[0084] In one preferred embodiment, the aerosol-forming substrate comprises a homogenized tobacco material. As used herein, the term "homogenized tobacco material" refers to a material formed by agglomerating particulate tobacco.

[0085] The aerosol-forming substrate preferably comprises an assembly of a sheet of homogenized tobacco material. As used herein, the term "sheet" refers to a layered element having a width and length substantially greater than its thickness. As used herein, the term "assembled" is used to describe a sheet that is rolled, folded, or otherwise compressed or clamped substantially transversely to the longitudinal axis of the aerosol-generating article.

[0086] The aerosol-forming substrate preferably comprises an aerosol former. As used herein, the term "aerosol former" is used to describe any suitable known compound or mixture of compounds that facilitates the formation of an aerosol during use and that is generally resistant to thermal decomposition at the operating temperatures of the aerosol-generating article.

[0087] Suitable aerosol formers are known in the art and include, but are not limited to, polyhydric alcohols (such as propylene glycol, triethylene glycol, 1,3-butanediol, glycerin, etc.), esters of polyhydric alcohols (such as glycerol monoacetate, diacetate, triacetate, etc.), and aliphatic esters of mono-, di-, or polycarboxylic acids (such as dimethyl dodecanedioate, dimethyl tetradecanedioate, etc.). Preferred aerosol formers are polyhydric alcohols (e.g., propylene glycol, triethylene glycol, 1,3-butanediol, and most preferably, glycerin) or mixtures thereof.

[0088] The aerosol-forming substrate may comprise a single aerosol former, or alternatively, the aerosol-forming substrate may comprise a combination of two or more aerosol formers.

[0089] The present invention is defined in the claims. However, below is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of the other examples, embodiments, or aspects described herein. EXAMPLES

[0090] Example 1: An aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol during a use session, the aerosol generating device comprising control electronics and a substantially linear first lighting array and a substantially linear second lighting array, each of the first and second lighting arrays extending over a length between a first end and a second end of the respective lighting array, the control electronics being coupled to the first and second lighting arrays and configured to operate either or both of the first and second lighting arrays to generate a predetermined light emission indicative of at least one of: i) a status of the aerosol generating device, and ii) a progression of an operational stage of the aerosol generating device. Example 2: An aerosol generating device according to Example 1, wherein the control electronics is configured to operate either or both of the first and second lighting arrays at two or more brightness levels to control the brightness of a given light emission. Example 3: An aerosol generating device according to any one of Examples 1 or 2, wherein the control electronics is configured to operate either or both of the first and second lighting arrays in two or more color states to control the color of a predetermined light emission. Example 4: An aerosol generating device according to any one of Examples 1 to 3, wherein the control electronics is configured to operate either or both of the first and second lighting arrays to vary a predetermined light emission over time. Example 5: An aerosol generating device according to Example 4, wherein the control electronics is configured to activate either or both of the first and second lighting arrays to vary a predetermined light emission over time to indicate a progression of operational stages of the aerosol generating device. Example 6: An aerosol generating device according to Example 5, wherein the progression of operational stages is the progression of a usage session. Example 7: An aerosol generating device according to any one of Examples 4 to 6, wherein the control electronics is configured to operate either or both of the first and second lighting arrays to vary the operating length of each lighting array over time. Example 8: An aerosol generating device according to any one of Examples 4 to 7, wherein the control electronics is configured to vary the predetermined light emission over time in one or more of brightness and color. Example 9: An aerosol generating device according to any one of Examples 4 to 8, wherein the control electronics is configured to vary the predetermined light emission over time by one or more of activating, deactivating, and reactivating different portions of either or both of the first and second lighting arrays over time. Example 10: An aerosol generating device according to any one of Examples 1 to 9, wherein each of the first and second lighting arrays includes a plurality of light-emitting units distributed between a first end and a second end of the respective lighting array. Example 11: An aerosol generating device according to Example 10, further comprising one or more waveguides configured to direct light generated by one or more of the plurality of light emitting units to one or more display windows so that a user can view a predetermined light emission. Example 12: An aerosol generating device according to any one of Examples 10 or 11, wherein each of the plurality of light-emitting units includes a light-emitting diode, the control electronics includes a light-emitting diode control driver and a separate microcontroller, and the control driver is configured to control, under the control of the microcontroller, the electrical supply from the power source to one or more of the plurality of light-emitting diodes of either or both of the first and second lighting arrays to generate a predetermined light emission. Example 13: An aerosol generating device according to Example 12, wherein the plurality of light-emitting diodes of each of the first and second lighting arrays include one or more light-emitting diodes of a first set configured to emit light of a first color and one or more light-emitting diodes of a second set configured to emit light of a second color, and the light-emitting diode control driver is configured to operate one or more of the light-emitting diodes from only the first set of either or both of the first and second lighting arrays, or from only the second set of either or both of the first and second lighting arrays, or from both the first and second sets of either or both of the first and second lighting arrays, to control the color of the predetermined light emission. Example 14: An aerosol generating device according to any one of Examples 12 or 13, wherein an LED control driver is configured to control electrical supply from a power source to one or more of the plurality of LEDs of either or both of the first and second lighting arrays by a type of pulse width modulation having a predetermined resolution to control the brightness of a predetermined light emission, the predetermined resolution defining two or more brightness levels. Example 15: An aerosol generating device according to any one of Examples 1 to 14, wherein the length of the first lighting array is the same as the length of the second lighting array. Example 16: An aerosol generating device according to any one of Examples 1 to 15, wherein the first lighting array and the second lighting array are laterally spaced apart from each other and parallel to each other. Example 17: An aerosol generating device according to any one of Examples 1 to 16, wherein the predetermined light radiation is one or more of a usage session light radiation, a low energy light radiation, a thermal profile light radiation, a pause light radiation, a state change light radiation, a progression light radiation, and a preheat light radiation. Example 18: An aerosol generating device according to any one of Examples 1 to 17, further comprising a substantially linear third lighting array positioned between and parallel to each of the first and second lighting arrays, and control electronics configured to operate the third lighting array alone or in addition to either or both of the first and second lighting arrays to generate a predetermined light radiation. Example 19: 19. The aerosol generating device according to any one of Examples 1 to 18, further comprising a power source coupled to the control electronics, the control electronics configured to determine a level of energy contained in the power source and compare the determined level of energy to first and second predetermined energy thresholds, the first predetermined energy threshold corresponding to a power source containing sufficient energy to complete a single use session and the second predetermined energy threshold corresponding to a power source containing sufficient energy to complete two or more use sessions, and in response to a first state in which the determined level of energy is sufficient to complete a single use session, activate either or both of the first and second lighting arrays to generate a single use session light emission, and in response to a second state in which the determined level of energy is sufficient to complete two or more use sessions, activate either or both of the first and second lighting arrays to generate a multiple use session light emission, wherein the single use session light emission and the multiple use session light emission are different from each other, the single use session light emission indicating a first state and the multiple use session light emission indicating a second state. Example 20: An aerosol generating device according to Example 19, wherein the control electronics is configured to operate either or both of the first and second lighting arrays in a greater proportion to generate a multiple use session light radiation than to generate a single use session light radiation. Example 21: An aerosol generating device according to any one of Examples 19 or 20, wherein the control electronics is configured to, in response to a first state, activate all or a portion of only the first lighting array to generate a single use session light radiation, and to, in response to a second state, activate all or a portion of both the first lighting array and the second lighting array to generate multiple use session light radiation. Example 22: An aerosol generating device according to Example 21, wherein the control electronics is configured to activate 90%-100% of the length of the first lighting array to generate a single use session light radiation, and to activate 90%-100% of the length of both the first lighting array and the second lighting array to generate multiple use session light radiation. Example 23: An aerosol generating device according to any one of Examples 19 to 22, wherein the control electronics is configured to operate either or both of the first and second lighting arrays such that the single use session light emissions and the multiple use session light emissions differ from each other in one or more of brightness and color. Example 24: An aerosol generating device according to Example 23, wherein the control electronics is configured to operate either or both of the first and second lighting arrays such that the single use session light radiation has a first predetermined brightness and the multiple use session light radiation has a second predetermined brightness, the second predetermined brightness being greater than the first predetermined brightness. Example 25: An aerosol generating device according to any one of Examples 1 to 24, further comprising a power source coupled to control electronics, the control electronics being configured to determine a level of energy contained in the power source, compare the determined level of energy with a predetermined threshold level of energy, and in response to the determined level of energy being below the predetermined threshold level of energy, activate either or both of the first and second lighting arrays to generate low-energy light radiation, the low-energy light radiation indicating that the determined level of energy is below the predetermined threshold level of energy. Example 26: 26. An aerosol generating device according to example 25, wherein the predetermined threshold level of energy is 20% or less of the predetermined energy capacity of the power source. Example 27: An aerosol generating device according to any one of Examples 25 or 26, wherein the control electronics is configured to operate either or both of the first and second lighting arrays so that the low energy light radiation has a predetermined color. Example 28: An aerosol generating device according to any one of Examples 25 to 27, wherein the control electronics is configured to activate a small proportion of either or both of the first and second lighting arrays to generate low energy light radiation. Example 29: 29. An aerosol generating device according to example 28, wherein the small proportion forms less than 15%, or preferably less than 10%, or preferably less than 5% of the length of either or both of the first and second illumination arrays. Example 30: 30. An aerosol generating device according to any one of Examples 28 or 29, wherein the small proportion is located at one of the first or second ends of either or both of the first and second lighting arrays. Example 31: The aerosol generating device according to any one of Examples 1 to 30, further comprising a power source coupled to the control electronics, the control electronics configured to receive a selection input selecting at least one of first and second predetermined thermal profiles, each of the first and second predetermined thermal profiles defining a heating profile for heating the aerosol-forming substrate by the electric heating arrangement over a usage session, the first and second predetermined thermal profiles being different from each other, control a supply of energy from the power source to the electric heating arrangement to heat the aerosol-forming substrate in accordance with the selected thermal profile, and in response to the selection of the first predetermined thermal profile, activate either or both of the first and second illumination arrays to generate a first predetermined thermal profile light radiation, and in response to the selection of the second predetermined thermal profile, activate either or both of the first and second illumination arrays to generate a second thermal profile light radiation, the first thermal profile light radiation indicating the selection of the first predetermined thermal profile and the second thermal profile light radiation indicating the selection of the second predetermined thermal profile. Example 32: 32. An aerosol generating device according to embodiment 31, wherein the second predetermined thermal profile has a greater intensity than the first predetermined thermal profile. Example 33: An aerosol generating device according to Example 32, wherein the second predetermined thermal profile is associated with a greater amount of energy being supplied from the power source to the electrical heating arrangement over a usage session than for the first predetermined thermal profile. Example 34: An aerosol generating device according to any one of Examples 31 to 33, wherein the aerosol generating device is provided with a user interface operable for a user to select between a first predetermined thermal profile and a second predetermined thermal profile, preferably the user interface including a button or a motion sensor. Example 35: An aerosol generating device according to Example 34, wherein the control electronics are configured to generate a selection input in response to a user selecting between a first predetermined thermal profile and a second predetermined thermal profile via a user interface. Example 36: An aerosol generating device according to any one of Examples 31 to 35, wherein the control electronics is configured to operate either or both of the first and second lighting arrays in a first proportion to generate a first thermal profile light radiation in response to selection of a first predetermined thermal profile, and to operate either or both of the first and second lighting arrays in a second proportion to generate a second thermal profile light radiation in response to selection of a second predetermined thermal profile, the second proportion being greater than the first proportion. Example 37: 37. An aerosol generating device according to embodiment 36, wherein the second proportion defines a proportion of the combined length of the first and second illumination arrays that is greater than the first proportion. Example 38: An aerosol generating device according to any one of Examples 31 to 37, wherein the first and second lighting arrays collectively include a plurality of lighting elements, and the control electronics is configured to activate a greater number of the plurality of lighting elements to generate the second thermal profile light radiation than those to generate the first thermal profile light radiation. Example 39: An aerosol generating device according to any one of Examples 31 to 38, wherein the control electronics is configured to activate all or a portion of only the first lighting array to generate a first thermal profile light radiation, and to activate all or a portion of only the second lighting array to generate a second thermal profile light radiation. Example 40: An aerosol generating device according to Example 39, wherein the control electronics is configured to activate a first proportion of the length of the first lighting array to generate a first thermal profile light radiation and to activate a second proportion of the length of the second lighting array to generate a second thermal profile light radiation, the second proportion value being greater than the first proportion value. Example 41: An aerosol generating device according to any one of Examples 31 to 40, wherein the control electronics is configured to operate either or both of the first and second lighting arrays such that the first thermal profile light emission and the second thermal profile light emission differ from each other in one or more of brightness and color. Example 42: An aerosol generating device according to Example 41, wherein the control electronics is configured to operate either or both of the first and second lighting arrays such that the first thermal profile light radiation has a first predetermined color and the second thermal profile light radiation has a second predetermined color, and the dominant wavelength of the second thermal profile light radiation is greater in size than the dominant wavelength of the first thermal profile light radiation. Example 43: An aerosol generating device according to any one of Examples 1 to 42, further comprising a power source coupled to the control electronics, the control electronics being configured to control the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate to a first temperature level in the aerosol emission mode, and in response to a pause signal, to control the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate to a second temperature level less than the first temperature level in the pause mode, and in response to the pause signal, to activate either or both of the first and second lighting arrays to generate a pause light emission, the pause light emission indicating that the aerosol generating device is in the pause mode. Example 44: An aerosol generating device according to Example 43, wherein the aerosol generating device is provided with a motion sensor for detecting movement of the aerosol generating device, the motion sensor being coupled to the control electronics, and the control electronics being configured to use the detected movement to trigger a pause signal. Example 45: An aerosol generating device according to Example 44, wherein the aerosol generating device is provided with a motion sensor for detecting a lack of movement of the aerosol generating device, the motion sensor being coupled to the control electronics, and the control electronics being configured to use the detected lack of movement to trigger a pause signal. Example 46: An aerosol generating device according to Example 45, wherein the lack of movement of the aerosol generating device is detected by the absence of movement of the device for a predetermined period of time, or the absence of movement above a certain magnitude for a predetermined period of time. Example 47: An aerosol generating device according to Example 43, further comprising a user interface and / or a puff detection mechanism for detecting puffs at the device, and wherein the control electronics are configured to trigger a pause signal in response to detecting an absence of user interaction with the user interface and / or the puff detection mechanism for a predetermined period of time. Example 48: An aerosol generating device according to Example 44, wherein the control electronics are configured to use the detected motion to trigger a pause signal when the detected motion corresponds to a predetermined motion. Example 49: An aerosol generating device according to any one of Examples 43 to 48, wherein the aerosol generating device is provided with an orientation sensor for detecting an orientation of the aerosol generating device, the orientation sensor being coupled to the control electronics, and the control electronics being configured to use the detected orientation, or the absence of a change in the detected orientation for a predetermined time, to trigger a pause signal. Example 50: An aerosol generating device according to example 49, wherein the control electronics is configured to use the detected orientation to trigger a pause signal when the detected orientation corresponds to a predetermined orientation. Example 51: The aerosol generating device according to any one of Examples 43 to 50, wherein the aerosol generating device further comprises a user interface operable by a user to initiate the pause mode, preferably the user interface comprising a button. Example 52: An aerosol generating device according to Example 51, wherein the control electronics are configured to generate a pause signal in response to a user initiating a pause mode via the user interface or in response to detecting an absence of user interaction with the user interface after a predetermined length of time. Example 53: An aerosol generating device according to any one of Examples 43 to 52, wherein the control electronics is configured to activate a portion of each of the first and second lighting arrays to generate suspended light radiation, the first and second lighting arrays are arranged relative to each other so that each portion of the first and second lighting arrays are parallel to each other, and each portion of the first and second lighting arrays have substantially the same length. Example 54: An aerosol generating device according to Example 53, wherein the control electronics is configured to sequentially activate and deactivate respective portions of the first and second lighting arrays to generate a suspended light emission. Example 55: An aerosol generating device according to Example 54, wherein the control electronics is configured to activate and deactivate respective portions of the first and second lighting arrays out of phase with each other to generate suspended light radiation. Example 56: An aerosol generating device according to any one of Examples 53 to 55, wherein the control electronics is configured to activate respective portions of the first and second lighting arrays to vary at least one of the brightness or wavelength over time to vary the brightness or color of the suspended light radiation over time. Example 57: An aerosol generating device according to any one of Examples 43 to 56, wherein the control electronics is configured to operate all or a portion of each of the first and second lighting arrays to generate a suspended light emission such that a central portion of each of the first and second lighting arrays has a greater brightness than the remaining portions of the respective lighting arrays. Example 58: An aerosol generating device according to Example 57, wherein the control electronics is configured to activate all or a portion of each of the first and second lighting arrays to generate a paused light emission such that the brightness of each of the first and second lighting arrays gradually decreases when moving from a central portion to the first and second ends of the respective lighting arrays. Example 59: An aerosol generating device according to any one of Examples 1 to 58, further comprising a power source coupled to control electronics, the control electronics configured to receive an input for changing an operating state of the aerosol generating device, control the supply of energy from the power source to change the operating state, and in response to the input, activate either or both of the first and second lighting arrays to generate state change light radiation, the state change light radiation indicating receipt of an input for changing the operating state. Example 60: 60. An aerosol generating device according to Example 59, wherein the change in operational state comprises activation of the device from an off mode or reactivation of the device from a pause mode. Example 61: An aerosol generating device according to Example 60, wherein re-activation of the device corresponds to the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate at a first temperature level in the aerosol emission mode, and wherein the pause mode corresponds to the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate at a second temperature less than the first temperature level. Example 62: An aerosol generating device according to any one of Examples 59 to 61, wherein the control electronics is configured to progressively activate each of the first and second lighting arrays over a predetermined period of time to progressively increase the activation length of each of the first and second lighting arrays over a predetermined period of time for state-changing light emission. Example 63: An aerosol generating device according to any one of Examples 59 to 62, wherein the control electronics is configured to operate all or a portion of each of the first and second lighting arrays to gradually increase brightness over a predetermined period of time for state-changing light emission. Example 64: An aerosol generating device according to Example 63, wherein the control electronics are configured to operate all or a portion of each of the first and second lighting arrays such that, at the beginning of a predetermined period, the brightness of the activated portions of each of the first and second lighting arrays gradually decreases with distance from the center of the activated portions of the respective lighting arrays toward the first and second ends, and the brightness gradually increases over the predetermined period such that, at the end of the predetermined period of the activated portions of each of the first and second lighting arrays, the brightness has a uniform brightness over the length of the activated portions of the respective lighting arrays. Example 65: An aerosol generating device according to any one of Examples 63 or 64, wherein the control electronics is configured to operate all or a portion of each of the first and second predetermined lighting arrays such that the brightness of the activated portions of each of the first and second predetermined lighting arrays is symmetrical about the center of the activated portions of the respective lighting arrays over a predetermined period of time. Example 66: An aerosol generating device according to any one of Examples 1 to 65, further comprising a power source coupled to control electronics, the control electronics being configured to control the supply of energy from the power source to the electrical heating arrangement over a use session to heat the aerosol-forming substrate, determine progress through the use session by referring to parameters indicative of progress through the use session, and operate either or both of the first and second lighting arrays to generate progressing light radiation that varies in response to progress through the use session such that the progressing light radiation is indicative of progress through the use session. Example 67: An aerosol generating device according to Example 66, wherein the parameters indicative of progress through the use session include one or more of the cumulative time elapsed since the start of the use session, the cumulative number of puffs in a series of puffs drawn by the user since the start of the use session, and the cumulative volume of aerosol emitted from the aerosol-forming substrate since the start of the use session. Example 68: An aerosol generating device according to Example 67, wherein the control electronics are configured to reduce or terminate the supply of energy from the power source to the electric heating arrangement to complete the use session when the cumulative time elapsed since the start of the use session reaches a predetermined maximum duration. Example 69: An aerosol generating device according to Example 68, wherein the control electronics is configured to first reduce or terminate the supply of energy from the power source to the electrical heating arrangement to complete a use session when i) the cumulative time elapsed since the start of the use session reaches a predetermined maximum duration, and ii) the cumulative number of puffs reaches a predetermined maximum number of puffs. Example 70: An aerosol generating device according to any one of Examples 68 or 69, wherein the control electronics is configured to first reduce or terminate the supply of energy from the power source to the electrical heating arrangement to complete a use session when i) the cumulative time elapsed since the start of the use session reaches a predetermined maximum duration, and ii) the cumulative volume of the aerosol reaches a predetermined volume limit. Example 71: An aerosol generating device according to any one of Examples 66 to 70, wherein the control electronics are configured to activate all or a majority of the first lighting array at the start of a first use session, and progressively stop the first lighting array to progressively reduce the operating length of the first lighting array as the first use session progresses, and to activate all or a majority of the second lighting array at the start of a second use session, and progressively stop the second lighting array to progressively reduce the operating length of the second lighting array as the second use session progresses. Example 72: An aerosol generating device according to Example 71, wherein the control electronics is configured to prevent light from being emitted from the first lighting array upon completion of a first use session, and to prevent light from being emitted from the second lighting array upon completion of a second use session. Example 73: An aerosol generating device according to any one of Examples 71 or 72, wherein the control electronics is configured to maintain the second lighting array in a deactivated state over a first use session and to maintain the first lighting array in a deactivated state over a second use session. Example 74: An aerosol generating device according to any one of Examples 66 to 73, wherein the first and second lighting arrays are arranged parallel to each other, and the control electronics are configured to activate all or a majority of both the first and second lighting arrays at the start of a use session, and to progressively shut down the first and second lighting arrays in sync with each other so that the activation length of each of the first and second lighting arrays gradually decreases as the use session progresses, such that the respective activation lengths of the first and second lighting arrays remain equal during the use session. Example 75: An aerosol generating device according to any one of Examples 66 to 74, wherein the first and second lighting arrays are arranged parallel to each other in a collective arrangement, the collective arrangement of the first and second lighting arrays having a length and a width, and the control electronics are configured to activate all or a majority of both the first lighting array and the second lighting array at the start of a use session and to progressively shut down the first and second lighting arrays in a serpentine manner across and along the length of the collective arrangement to progressively reduce the activation length of each of the first and second lighting arrays as the use session progresses. Example 76: An aerosol generating device according to any one of Examples 66 to 75, further comprising a substantially linear third lighting array positioned parallel between each of the first and second lighting arrays, and the control electronics configured to activate all or a majority of the third lighting array at the start of a use session and progressively deactivate the third lighting array to progressively reduce the activation length of the third lighting array as the use session progresses. Example 77: An aerosol generating device according to Example 76, wherein the control electronics is configured to prevent light from being emitted from the third lighting array upon completion of a usage session. Example 78: An aerosol generating device according to any one of Examples 76 or 77, wherein the control electronics are configured to maintain the first and second lighting arrays in a deactivated state throughout a usage session. Example 79: An aerosol generating device according to any one of Examples 1 to 78, further comprising a power source coupled to the control electronics, the aerosol generating device configured to receive an aerosol generating article comprising an aerosol-forming substrate, the control electronics configured to detect receipt of the aerosol generating article by the aerosol generating device, control the supply of energy from the power source to the electrical heating arrangement to activate a pre-heating stage in which the electrical heating arrangement is heated to a predetermined target temperature, and activate either or both of the first and second lighting arrays to generate pre-heating light radiation, the pre-heating light radiation varying in response to progression through the pre-heating stage to indicate progression through the pre-heating stage. Example 80: An aerosol generating apparatus according to Example 79, wherein the aerosol generating apparatus has a cavity for receiving an aerosol generating article, the aerosol generating article including an inductively heatable susceptor, the electric heating arrangement includes an induction heating arrangement coupled to a power source and configured to generate an alternating magnetic field in the cavity to inductively heat the susceptor of the aerosol generating article when the aerosol generating article is received in the cavity, and a control circuit is configured to generate probe power pulses to intermittently turn on the induction heating arrangement and detect a change in at least one characteristic of the induction heating arrangement due to the presence of the susceptor when the aerosol generating article is received in the cavity, thereby enabling detection that the aerosol generating article has been received in the cavity. Example 81: An aerosol generating device according to embodiment 80, wherein at least one characteristic is the equivalent resistance of the induction heating arrangement or the inductance of the induction heating arrangement. Example 82: An aerosol generating device according to any one of Examples 79 to 81, wherein the control electronics is configured to operate the first and second lighting arrays such that different portions of each of the first and second lighting arrays vary in brightness over time and relative to each other, and such that the brightness of each of the first and second lighting arrays increases progressively throughout the pre-heating stage. Example 83: An aerosol generating device according to any one of Examples 79 to 82, wherein the control electronics is configured to operate the first and second lighting arrays so that the dominant wavelength of the predetermined light emission is gradually increased throughout the preheating stage. Example 84: An aerosol generating device according to any one of Examples 79 to 83, wherein the first and second lighting arrays are arranged parallel to each other and the control electronics are configured to operate the first and second lighting arrays in synchronization with each other so as to progressively increase the operating length of each of the first and second lighting arrays as the pre-heating stage progresses, such that the respective operating lengths of the first and second lighting arrays remain equal during a usage session. Example 85: An aerosol generating device according to any one of Examples 79 to 84, wherein the first and second lighting arrays are arranged parallel to each other in an ensemble arrangement, the ensemble arrangement having a length and a width, and the control electronics are configured to operate the first and second lighting arrays in a serpentine manner across and along the width of the ensemble arrangement to progressively increase the operating length of each of the first and second lighting arrays as they progress through the pre-heating stage. Example 86: An aerosol generating device according to any one of Examples 79 to 85, wherein the control electronics is configured to operate the first and second lighting arrays during or upon completion of the preheating phase such that the brightness of the respective operating lengths of the first and second lighting arrays gradually increases with increasing distance between the first and second opposing ends of the respective operating lengths. Example 87: An aerosol generating device according to any one of Examples 79 to 86, wherein the control electronics is configured to operate the first and second lighting arrays during or upon completion of the preheating phase such that the dominant wavelength of the preheating light radiation increases progressively with the distance between the first and second opposing ends of the respective operating lengths of the first and second lighting arrays. Example 88: An aerosol generating device according to example 87, wherein the dominant wavelength is in the range of 380 to 750 nanometers, such that during or upon completion of the preheating stage, the first opposing end defines a blue color of preheating light radiation and the second opposing end defines a red color of preheating light radiation. Example 89: An aerosol generating device according to any one of Examples 79 to 88, wherein the control electronics is configured so that both the first and second lighting arrays have uniform brightness along the length of their respective lighting arrays upon completion of the pre-heating stage. [Brief description of the drawings]

[0091] The embodiments will now be further described with reference to the following figures:

[0092] [Figure 1] FIG. 1 shows a schematic side view of an aerosol generating device. [Diagram 2] FIG. 2 shows a schematic top view of the aerosol generating device of FIG. [Diagram 3] FIG. 3 shows a schematic cross-sectional side view of the aerosol generating device of FIG. 1 and an aerosol-generating article for use in the device. [Figure 4] FIG. 4 is a block diagram providing a schematic view of the various electronic components of the aerosol generating device of FIGS. 1-3 and their interactions. [Diagram 5] FIG. 5 shows an example of the operation of the linear illumination array arrangement provided on the aerosol generating device of FIGS. 1-4 as it progresses through a pre-heating stage of operation. [Figure 6] FIG. 6 illustrates an example of operation of a lighting array arrangement as it progresses through a use session, the use session beginning immediately after the pre-heat stage of operation illustrated in FIG. [Figure 7] FIG. 7 illustrates a further example of the operation of the lighting array arrangement as it progresses through a pre-heating stage of operation. [Figure 8] FIG. 8 shows a further example of the operation of a lighting array arrangement as it progresses through a use session, the use session commencing immediately after the pre-heat stage shown in FIG. [Figure 9]FIG. 9 illustrates an example of the operation of the lighting array configuration as it progresses through a first use session. [Figure 10] FIG. 10 illustrates an example of operation of a lighting array arrangement as it progresses through a second use session, which follows the first use session illustrated in FIG. [Figure 11] FIG. 11 shows a further example of the operation of the arrangement of a lighting array as it progresses through a usage session. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0093] The exemplary aerosol generating device 10 is a handheld aerosol generating device and has an elongated shape defined by a housing 20 that is generally circular and cylindrical (see Figures 1 and 2). As shown in Figures 2 and 3, the aerosol generating device 10 comprises an open cavity 25 located at the proximal end 21 of the housing 20 for receiving an aerosol-generating article 30. In addition, the aerosol generating device 10 further comprises an electrically operated heater element 40 arranged to heat at least the aerosol-forming substrate 31 of the aerosol-generating article when the aerosol-generating article 30 is received in the cavity 25 (see Figure 3).

[0094] The aerosol-generating device is configured to receive an aerosol-generating article 30. As shown in FIG. 3, the aerosol-generating article 30 has the form of a cylindrical rod, which is formed by the combination of an aerosol-forming substrate 31 and a filter element 32. The aerosol-forming substrate 31 and the filter element 32 are aligned coaxially and enclosed in a cigarette paper wrapper 33. The aerosol-forming substrate 31 is a solid aerosol-forming substrate comprising tobacco. However, in an alternative embodiment (not shown), the aerosol-forming substrate 31 may instead be a liquid aerosol-forming substrate or may be formed of a combination of liquid and solid aerosol-forming substrates. The filter element 32 serves as the mouthpiece of the aerosol-generating article 30. The aerosol-generating article 30 has a diameter approximately equal to the diameter of the cavity 25 of the device 10 and a length greater than the depth of the cavity 25. When the aerosol-generating article 30 is received within the cavity 25 of the device 10, a portion of the article containing the filter element 32 extends outside the cavity and can be withdrawn by the user in the same manner as a conventional cigarette.

[0095] An arrangement of three linear illumination arrays 61, 62, 63 is incorporated in the housing 20 of the aerosol generating device 10 (see FIG. 1). The arrangement consists of a first linear illumination array 61 and a second linear illumination array 62 arranged on either side of a third linear illumination array 63. Thus, the third linear illumination array 63 is located in the middle between the first illumination array 61 and the second illumination array 62. Each illumination array 61, 62, 63 is formed of a linear arrangement of six light emitting diodes 611a...f, 621a...f, 631a...f extending between a first end 612, 622, 632 and a second end 613, 623, 633 of the respective illumination array. All three illumination arrays 61, 62, 63 have the same length and are arranged parallel to each other, with their respective first and second ends aligned with each other. Each lighting array 61, 62, 63 has a respective viewing window 614, 624, 634 which forms part of the exterior surface of the housing 20 and is light transmissive. As explained in more detail below, light generated by the light emitting diodes of each lighting array 61, 62, 63 is directed towards its respective viewing window 614, 624, 634 so as to be visible to a user of the aerosol generation device 10 during use.

[0096] The battery 11 and the microcontroller 12 are coupled to each other and located within the housing 20 (see FIG. 4). The microcontroller 12 also incorporates a memory module 12a. The microcontroller 12 is in turn coupled to both the heater elements 40 and the lighting control driver 13. The microcontroller 12 and the lighting control driver 13 collectively form the control electronics section 100 of the aerosol generating device 10. The lighting control driver 13 is coupled to each of the light emitting diodes 611a...f, 621a...f, 631a...f of each lighting array 61, 62, 63. For the first lighting array 61, a waveguide 615a...f is provided between the light emitting diodes 611a...f and the viewing window 614. Similarly, for the second lighting array 62, a waveguide 625a...f is provided between the light emitting diodes 621a...f and the viewing window 624. For the third lighting array 63, waveguides 635a...f are also provided between the light emitting diodes 631a...f and the viewing window 634. Each of the waveguides 615a...f, 625a...f, 635a...f is associated with a respective one of the light emitting diodes 611a...f, 621a...f, 631a...f of the respective lighting arrays 61, 62, 63, such that, in use, each waveguide functions to direct light generated by an associated one of the light emitting diodes towards a respective viewing window 614, 624, 634. The waveguides 615a...f, 625a...f, 635a...f are in the form of discrete lengths of optical fibre.

[0097] The memory module 12a includes instructions that are executed by the microcontroller 12 and the lighting control driver 13 during use of the device 10. The instructions stored in the memory module 12a include data regarding two or more user-selectable predefined thermal profiles for the heater element 40, criteria for determining the duration of a usage session, and other data and information related to the control and operation of the aerosol generating device 10. When activated, the microcontroller 12 accesses the instructions contained in the memory module 12a and controls the supply of energy from the battery 11 to the heater element 40 according to the instructions contained in the memory module 12a. The microcontroller 12 also controls the supply of energy to the lighting control driver 13. The lighting control driver 13 then individually controls the electrical supply to each of the light-emitting diodes 611a...f, 621a...f, 631a...f of the lighting arrays 61, 62, 63, such that each light-emitting diode emits light 616a...f, 626a...f, 636a...f at one of a plurality of distinct static brightness levels under the control of the lighting control driver (see FIG. 4). Under the control of the lighting control driver 13, the light emitted by the different light emitting diodes of the three linear lighting arrays 61, 62, 63 together form a predetermined light emission. The three different forms of cross-hatching used in Fig. 4 for the light 616a...f, 626a...f, 636a...f generated by different ones of the light emitting diodes of the first lighting array 61, the second lighting array 62 and the third lighting array 63 represent three different static brightness levels.

[0098] For the time shown in Fig. 4, the brightness of each of the three lighting arrays 61, 62, 63 is symmetrical about the center of the respective lighting array, and each of the three lighting arrays has the same brightness variation over the length of the lighting array. Thus, referring to the first lighting array 61, the two centrally located light-emitting diodes 611c, d are independently controlled by the lighting control driver 13 to emit light at a first predetermined static brightness level, the adjacent light-emitting diodes 611b, e are independently controlled to emit light at a second predetermined static brightness level, and the outermost light-emitting diodes 611a, f are independently controlled to emit light at a third predetermined static brightness level. The second lighting array 62 and the third lighting array 63 are controlled by the lighting control driver 13 to exhibit the same brightness variation over their lengths as the first lighting array 61.

[0099] In use, a user first inserts an aerosol-generating article 30 into the cavity 25 of the aerosol-generating device 10 (as indicated by the arrow in FIG. 3 ) and presses a user button 50 to turn on the device 10 and activate the heater element 40 to begin a usage session. The button 50 is electromechanically coupled to the microcontroller 12 (see FIG. 4 ). In the illustrated embodiment, the button 50 also functions as a means for the user to select a given one of the predefined thermal profiles stored in the memory module 12a. For the illustrated embodiment, pressing the button 50 a second time functions to select a first predefined thermal profile, and pressing the button a third time functions to select a second predefined thermal profile. However, in alternative embodiments (not shown), an alternative user interface may be provided in which the user can interact with to select a desired one of the first and second predefined thermal profiles. Such an alternative user interface may be in the form of a touch-sensitive panel with which the user may engage a finger to select a desired one of the predefined thermal profiles, the touch-sensitive panel being coupled to the microcontroller 12. Alternatively, an alternative user interface may include a motion or orientation sensor coupled to the microcontroller 12, where motion or gesture of the device 10 in a predetermined manner is detected by the sensor and serves as a means for selecting a particular one of the predetermined thermal profiles. The first and second predetermined thermal profiles differ from each other in intensity, the second predetermined thermal profile having a greater intensity than the first predetermined thermal profile. The second predetermined thermal profile is associated with the delivery of a greater amount of energy from the battery 11 to the heater element 40 over a usage session than the first predetermined thermal profile.

[0100] The temperature of the heater element 40 is raised in a pre-heating phase from ambient temperature to a pre-defined target temperature for heating the aerosol-forming substrate 31 according to a selected pre-defined thermal profile. Once the pre-defined target temperature is reached, a use session is initiated. The heater element 40 heats the aerosol-forming substrate 31 of the article 30 over the use session, so that volatile compounds of the aerosol-forming substrate are released and atomized to form an aerosol. The user inhales the aerosol generated from the heated aerosol-forming substrate 31 by utilizing the filter element 32 of the article 30. The microcontroller 12 is configured to control the supply of energy from the battery 11 to maintain the heater element 40 at a substantially constant level as the user puffs on the article 30. The heater element 40 continues to heat the aerosol-generating article 30 according to the selected pre-defined thermal profile until the end of the use session. At the end of the use session, the heater element 40 can be turned off and cooled. A use session has a maximum duration defined by a first pre-determined thermal profile that is generated by i) six minutes from activation of the heater element 40, or ii) a user applying twelve consecutive puffs on the aerosol-generating article 30. In an alternative embodiment, the maximum duration of a use session is instead defined such that the first pre-determined thermal profile is generated by i) six minutes from activation of the heater element 40, or ii) a cumulative volume of aerosol emitted from the aerosol-forming substrate over the use session reaching a pre-determined volume. In the illustrated embodiment, the heater element 40 is a resistive heater element. However, in other embodiments (not shown), the heater element 40 is instead in the form of a susceptor disposed within a varying magnetic field such that it is heated by induction.

[0101] At the end of a usage session, the aerosol-generating article 30 is removed from the device 10 for disposal, and the device may be coupled to an external power source for recharging the device's battery 11.

[0102] Fig. 5 shows an embodiment of how the lighting control driver 13 controls the electrical supply from the battery 11 to the individual ones of the light emitting diodes 611a...f, 621a...f, 631a...f of the first lighting array 61, the second lighting array 62 and the third lighting array 63 to generate a predetermined light emission indicative of the progression through the pre-heating stage of the operation of the aerosol generating device 10. The first, second and third lighting arrays form a collective lighting arrangement having a length L and a width W. As shown in the legend of Fig. 5, the light emitting diodes of each of the lighting arrays 61, 62, 63 are controlled by the lighting control driver 13 throughout the pre-heating stage to emit light having one of seven predetermined static brightness levels or are in a rest state where no light is emitted. The light collectively generated by the three lighting arrays 61, 62, 63 at a given time in the pre-heating stage defines a predetermined light emission indicative of the progression through the pre-heating stage of the operation. The predetermined static brightness levels are designated by levels 7, 6, 5, 4, 3, 2 and 1 in order of decreasing brightness, with the deactivated or "off" state designated by level 0. At the start of the pre-heating phase of operation, the lighting control driver 13 maintains all the light emitting diodes of the three lighting arrays 61, 62, 63 in a deactivated state in which no light is emitted, i.e. level 0 (see FIG. 5(a)). As it progresses through the pre-heating phase, the lighting control driver 13 controls the electrical supply to the light emitting diodes 611a...f, 621a...f, 631a...f of the lighting arrays 61, 62, 63 (see arrow S5) so as to progressively activate the lighting arrays in a serpentine manner along the length L of the collective lighting arrangement defined by the three lighting arrays, over the width W of the collective lighting arrangement. During the course of the pre-heating phase, the lighting control driver 13 progressively increases the static brightness levels of an increasing number of light emitting diodes of the collective lighting arrangement formed by the three lighting arrays 61, 62, 63, from level 0 to level 7. As shown in FIG. 5(g), at the end of the pre-heating phase, indicating that the heater elements 40 have achieved the predetermined target operating temperature, the light emitting diodes of all three lighting arrays are activated to emit light at their maximum static brightness level, i.e., level 7.

[0103] Fig. 6 shows an embodiment of how the lighting control driver 13 controls the electrical supply to individual ones of the light emitting diodes 611a...f, 621a...f, 631a...f of the first lighting array 61, the second lighting array 62 and the third lighting array 63 to generate a predetermined light emission indicative of the progression through a usage session. The usage session shown in Fig. 6 starts immediately after the completion of the pre-heating phase of operation shown in Fig. 5. As shown in the legend in Fig. 6, the light emitting diodes of each of the lighting arrays 61, 62, 63 are controlled by the lighting control driver 13 over the usage session to emit light having one of five predetermined static brightness levels or to be in a stopped state where no light is emitted. The light generated collectively by the three lighting arrays 61, 62, 63 at a given point in time of the usage session defines a predetermined light emission indicative of the progression through the usage session. The predetermined static brightness levels are indicated by levels 5, 4, 3, 2 and 1 in order of decreasing brightness, with the stopped or "off" state being indicated by level 0. At the beginning of a usage session, the lighting control driver 13 maintains the light emitting diodes 611a...f, 621a...f, 631a...f of all three lighting arrays 61, 62, 63 in a fully activated state in which all of the light emitting diodes generate light at a maximum static brightness level, i.e. level 5 (see FIG. 6(a)). As it progresses through the usage session, the lighting control driver 13 controls the electrical supply to the light emitting diodes 611a...f, 621a...f, 631a...f of the first lighting array 61, the second lighting array 62 and the third lighting array 63 (see arrows S6) so as to progressively shut down the lighting arrays in a serpentine manner along the length L of the collective lighting arrangement defined by the three lighting arrays, over the width W of the collective lighting arrangement. During the course of the usage session, the lighting control driver 13 progressively reduces the static brightness levels of an increasing number of light emitting diodes of the collective lighting arrangement formed by the three lighting arrays 61, 62, 63, from level 5 to level 0. As shown in FIG. 6(g), at the end of the usage session, all light emitting diodes in all three lighting arrays are in a deactivated state with no light being emitted, i.e., level 0.

[0104] Fig. 7 shows an embodiment of how the illumination control driver 13 controls the electrical supply to each of the light emitting diodes 611a...f, 621a...f, 631a...f of the first illumination array 61, the second illumination array 62 and the third illumination array 63 to generate a predetermined light emission indicative of the progression through the pre-heating stage of the operation of the aerosol generating device 10. As shown in the legend of Fig. 7, the light emitting diodes of each of the illumination arrays 61, 62, 63 are controlled by the illumination control driver 13 throughout the pre-heating stage to emit light having one of seven predetermined static brightness levels or to be in a deactivated state in which no light is emitted. The light collectively generated by the three illumination arrays 61, 62, 63 at a given time in the pre-heating stage defines a predetermined light emission indicative of the progression through the pre-heating stage of the operation. The predetermined static brightness levels are indicated by levels 7, 6, 5, 4, 3, 2 and 1 in order of decreasing brightness, with the deactivated or "off" state being indicated by level 0. At the beginning of the pre-heating phase of operation, the lighting control driver 13 maintains the light emitting diodes of all three lighting arrays 61, 62, 63 in a deactivated state in which no light is emitted, i.e. at level 0. As it progresses through the pre-heating phase, the lighting control driver 13 controls the electrical supply to the light emitting diodes 611a...f, 621a...f, 631a...f of the first lighting array 61, the second lighting array 62 and the third lighting array 63 (see arrow S7) so as to progressively activate the lighting arrays in a serpentine manner along the length L of the collective lighting arrangement defined by the three lighting arrays over the width W of the collective lighting arrangement. During the course of the pre-heating phase, the lighting control driver 13 progressively increases the static brightness levels of the different ones of the light emitting diodes of the collective lighting arrangement formed by the three lighting arrays 61, 62, 63 between different static brightness levels 1 to 7. 7(g), upon completion of the preheating stage, the corresponding light emitting diodes (designated with one of the letters a...f) of each lighting array 61, 62, 63 each emit light at a common static brightness level, such that each corresponding light emitting diode of each lighting array 61, 62, 63 generates a band of light at a particular one of the seven static brightness levels 1-7.Upon completion of the pre-heating phase, the collective lighting arrangement formed by the three lighting arrays 61, 62, 63 generates a predetermined light emission consisting of six bands of light, each band having a distinct static brightness level, with a gradual step-by-step increase in the static brightness level when moving from one band to another over the length L of the collective lighting arrangement.

[0105] Fig. 8 shows a further embodiment of how the lighting control driver 13 controls the electrical supply to individual ones of the light emitting diodes 611a...f, 621a...f, 631a...f of the first lighting array 61, the second lighting array 62 and the third lighting array 63 to generate a predetermined light emission indicative of the progression through the use session. The use session shown in Fig. 8 starts immediately after the completion of the pre-heating phase of operation shown in Fig. 7. As shown in the legend in Fig. 8, the light emitting diodes of each of the lighting arrays 61, 62, 63 are controlled by the lighting control driver 13 over the use session to emit light having one of seven predetermined static brightness levels or to be in a stopped state where no light is emitted. The light collectively generated by the three lighting arrays at a given point in time of the use session defines a predetermined light emission indicative of the progression through the use session. The predetermined static brightness levels are indicated by levels 7, 6, 5, 4, 3, 2 and 1 in order of decreasing brightness, with the stopped or "off" state being indicated by level 0. At the beginning of a use session (as shown in FIG. 8(a)), the lighting control driver 13 maintains the light emitting diodes 611a...f, 621a...f, 631a...f of all three lighting arrays 61, 62, 63 in the same band state as they were at the completion of the pre-heating phase of FIG. 7(g). As it progresses through the use session, the lighting control driver 13 controls the electrical supply to the light emitting diodes 611a...f, 621a...f, 631a...f of the first lighting array 61, the second lighting array 62 and the third lighting array 63 (see arrows S8) so as to progressively stop the lighting arrays in a serpentine manner along the length L of the collective lighting arrangement defined by the three lighting arrays over the width W of the collective lighting arrangement. In the course of the use session, the lighting control driver 13 progressively decreases the static brightness levels of an increasing number of light emitting diodes of the collective lighting arrangement formed by the three lighting arrays 61, 62, 63 from level 7 to level 0. At the end of the usage session, all light emitting diodes in all three lighting arrays are in a deactivated state with no light being emitted, ie level 0.

[0106] FIG. 9 shows an example of how the lighting control driver 13 controls the electrical supply to each of the light emitting diodes 611a...f of the first lighting array 61 to generate a predetermined light emission indicative of progression through a first use session. The battery 11 is provided in a fully charged state at the start of the first use session. The legend in FIG. 9 shows four different predetermined light static brightness levels, indicated as levels 4, 3, 2 and 1, as well as a stopped or "off" state, indicated as level 0. At the start of the first use session, all of the light emitting diodes 611a...f of the first lighting array 61 are controlled by the lighting control driver 13 to emit light at a peak static brightness level, i.e. level 4. As the first use session progresses, the lighting control driver 13 progressively decreases the activation length of the first lighting array 61 by progressively decreasing the static brightness levels of the light emitting diodes 611a...f from level 4 to level 3 to level 2 to a stopped state. The reduction in static brightness level begins with light emitting diode 611a and progresses downward in the direction of arrow A along the length of the first lighting array 61 to each successive light emitting diode of the lighting array 61. At the completion of the first use session, all of the light emitting diodes 611a...f of the first lighting array 61 are in a deactivated state, i.e. at level 0. Throughout the first use session, all of the light emitting diodes 621a...f are controlled by the lighting control driver 13 to emit light having a minimum static brightness level of level 1. The central or third lighting array 63 is controlled by the lighting control driver 13 such that it may be maintained in a deactivated state throughout the first use session.

[0107] FIG. 10 shows an example of how the lighting control driver 13 controls the electrical supply to individual ones of the light emitting diodes 621a...f of the second lighting array 62 to generate a predetermined light emission indicative of progression through a second usage session. The second usage session follows the first usage session, and the aerosol generating device 10 is powered over the second usage session using any energy remaining in the battery 11 after the first usage session. The legend in FIG. 10 shows two different predetermined light static brightness levels, indicated by levels 2 and 1, as well as a deactivated or "off" state, indicated by level 0. At the start of the second usage session, all of the light emitting diodes 621a...f of the second lighting array 62 are controlled by the lighting control driver 13 to emit light at a peak static brightness level, i.e. level 2. As the second usage session progresses, the lighting control driver 13 progressively decreases the activation length of the second lighting array 62 by progressively decreasing the static brightness levels of the light emitting diodes 621a...f from level 2 to level 1 to a deactivated state. The reduction in static brightness level begins with light emitting diode 621a and progresses downwards in the direction of arrow B along the length of the second lighting array 62 to each successive light emitting diode of the lighting array 62. At the completion of the use session, all of the light emitting diodes 621a...f of the second lighting array 62 are in the deactivated state, i.e. at level 0. Throughout the second use session, all of the light emitting diodes 611a...f, 631a...f of the first lighting array 61 and the third lighting array 63 are controlled by the lighting control driver 13 to be maintained in the deactivated state where no light is emitted.

[0108] Fig. 11 shows an example of how the lighting control driver 13 controls the electrical supply to individual ones of the light emitting diodes 631a...f of the central or third lighting array 63 to generate predetermined light emissions indicative of a progression through a usage session. The legend in Fig. 11 shows six different predetermined static brightness levels of light, indicated by levels 6, 5, 4, 3, 2 and 1, as well as a stopped or "off" state, indicated by level 0. At the start of a usage session, all of the light emitting diodes 631a...f of the third lighting array 63 are controlled by the lighting control driver 13 to define a gradual decrease in brightness between the light emitting diode 631a and the light emitting diode 631f. When moving downwards along the length of the lighting array 63, each successive light emitting diode of the lighting array 63 emits light at one of the predetermined static brightness levels lower than its predecessor. As the use session progresses, the lighting control driver 13 progressively reduces the activation length of the third lighting array 63 by progressively decreasing the static brightness levels of the light emitting diodes 631a...f from level 6 to a deactivated state. The decrease in static brightness level begins with the light emitting diode 631a and progresses downward in the direction of arrow C along the length of the third lighting array 63 to each successive light emitting diode of the lighting array 63. At the completion of the use session, all of the light emitting diodes 631a...f of the third lighting array 63 are in the deactivated state, i.e. level 0. Throughout the use session, all of the light emitting diodes of the first lighting array 61 and the second lighting array 62 are maintained in the deactivated state by the lighting control driver 13.

[0109] For the purposes of this specification and the appended claims, unless otherwise indicated, all numbers expressing amounts, quantities, percentages, and the like, should be understood in all instances as modified by the term "about." Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein. Thus, in this context, the number "A" is understood as "A" ± 10%. Within this context, the number "A" may be considered to include a numerical value that is within the general standard error for the measurement of the property that the number "A" modifies. The number "A" may, in some cases as used in the appended claims, deviate by the percentages recited above, provided that the amount by which "A" deviates does not materially affect the basic and novel property(ies) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed, and include any intermediate ranges therein, which may or may not be specifically recited herein.

Claims

1. An aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol during use, the aerosol generating device comprising: control electronics; a substantially linear first illumination array and a substantially linear second illumination array, each of the first and second illumination arrays extending over a length between a first end and a second end of the respective illumination array, a substantially linear first illumination array and a substantially linear second illumination array; the first and second illumination arrays each have the same length and are laterally spaced from each other in parallel and aligned, the first and second ends of the first illumination array being aligned with the first and second ends of the second illumination array; the control electronics being coupled to the first and second illumination arrays; i) the state of the aerosol generating device, and ii) in response to at least one of the progress of the operating phase of the aerosol generating device, configured to operate both the first and second illumination arrays to generate a predetermined light emission indicative thereof; An aerosol generating device, wherein the control electronics is configured to transmit different data to the user for each of the first and second illumination arrays.

2. The aerosol generating device according to claim 1, wherein the control electronics is configured to operate one or both of the first and second illumination arrays at two or more brightness levels to control the brightness of the predetermined light emission.

3. The aerosol generating device according to claim 1, wherein the control electronics is configured to operate one or both of the first and second illumination arrays in two or more color states to control the color of the predetermined light emission.

4. The aerosol generating device according to claim 1, wherein the control electronics is configured to operate one or both of the first and second illumination arrays to vary the predetermined light emission over time.

5. The aerosol generating device according to claim 4, wherein the control electronics is configured to operate one or both of the first and second illumination arrays to vary the predetermined light emission over time to indicate the progress of the operating phase of the aerosol generating device.

6. The aerosol generating device according to claim 5, wherein the progress of the operation stage is the progress of the usage session.

7. The aerosol generating device according to claim 4, wherein the control electronics is configured to operate either or both of the first and second lighting arrays to vary the operating length of each of the lighting arrays over time.

8. The aerosol generating device according to claim 4, wherein the control electronics is configured to vary the predetermined light emission over time in one or more of luminance and color.

9. The aerosol generating device according to claim 4, wherein the control electronics is configured to vary the predetermined light emission over time by one or more of the timed operation, stop, and re-operation of different portions of either or both of the first and second lighting arrays.

10. The aerosol generating device according to claim 1, wherein each of the first and second lighting arrays includes a plurality of light emitting units distributed between the first end and the second end of each of the lighting arrays.

11. The aerosol generating device according to claim 10, further comprising one or more waveguides configured to direct light generated by one or more of the plurality of light emitting units towards one or more display windows for viewing of the predetermined light emission by a user.

12. Each of the plurality of light emitting units includes a light emitting diode, the control electronics includes a light emitting diode control driver and a separate microcontroller, and the control driver is configured to control the electrical supply from a power source to one or more of the plurality of light emitting diodes of either or both of the first and second lighting arrays under the control of the microcontroller to generate the predetermined light emission.

13. The plurality of light emitting diodes of each of the first and second lighting arrays includes one or more light emitting diodes of a first set configured to emit light of a first color, and one or more light emitting diodes of a second set configured to emit light of a second color. The aerosol generating device according to claim 12, wherein the light emitting diode control driver is configured to activate one or more of the light emitting diodes from only the first set of either or both of the first and second illumination arrays, or from only the second set of either or both of the first and second illumination arrays, or from both the first and second sets of either or both of the first and second illumination arrays to control the color of the predetermined light emission.

14. The aerosol generating device according to claim 1, further comprising a substantially linear third illumination array positioned parallel to and between each of the first and second illumination arrays, wherein the control electronics is configured to operate the third illumination array alone or in addition to either or both of the first and second illumination arrays to generate the predetermined light emission.

15. The aerosol generating device according to any one of claims 1 to 14, wherein the predetermined light emission is one or more of an in-use session light emission, a low energy light emission, a heat profile light emission, a pause light emission, a state change light emission, a progress light emission, and a preheat light emission.

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