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 at least one illumination array including a plurality of light-emitting units. The control electronics is configured to independently control each of the plurality of light-emitting units in at least i) an off state in which the light-emitting units do not emit light, ii) a first illumination state in which the light-emitting units emit light at a first static brightness level, and iii) a second illumination state in which the light-emitting units emit light at a second static brightness level different from the first static brightness level. The control electronics is configured to control each of the light-emitting units to be in one of the off state, the first illumination state, and the second illumination state to indicate to a user a progression through operational stages 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. Summary of the Invention

[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.

[0006] According to one aspect of the invention, there is provided an aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol during a use session. The aerosol generating device comprises control electronics and at least one illumination array including a plurality of light-emitting units. The control electronics is configured to independently control each of the plurality of light-emitting units in at least i) an off state in which the light-emitting units do not emit light, ii) a first illumination state in which the light-emitting units emit light at a first static brightness level, and iii) a second illumination state in which the light-emitting units emit light at a second static brightness level different from the first static brightness level. The control electronics is configured to control each of the light-emitting units to be in one of the off state, the first illumination state, and the second illumination state to indicate to a user a progression through operational stages 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] 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 the 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 taken by a user after the start of a use session, and ii) a cumulative amount of aerosol emitted from an aerosol-forming substrate after the start of a use session.

[0009] In addition to the off state, the different static brightness levels of the first and second lighting states facilitate conveying more data to the user regarding the progression of operational stages via the first and second lighting states compared to when the lighting unit is controlled either fully on or fully off.

[0010] The lighting array may be substantially linear. Further, the lighting array may extend between a first end and a second end of the lighting array. The use of a linear lighting array provides a lighting array with a geometry that can efficiently track the progress of an operational step to provide a user with an indication of how the operational step is progressing.

[0011] In a preferred embodiment, the progression of operational stages of the aerosol generating device may be the progression of a usage session.

[0012] The control electronics may be configured to independently control each of a plurality of lighting units of the lighting array in a plurality of lighting states, where each lighting unit emits light at a different static brightness level. The use of different static brightness levels for each of the plurality of lighting states facilitates communicating data to the user regarding multiple incremental changes in the operational stage. The greater the number of static brightness levels for each lighting unit, the more data can be communicated to the user regarding the operational stage changes. In this manner, a high degree of accuracy of data can be delivered to the user regarding the status of the operational stage.

[0013] Preferably, in each of the plurality of lighting states, the brightness level of the light emitted from each lighting unit may be static, such that the brightness level remains substantially constant until the lighting unit leaves that lighting state. Maintaining a static or constant brightness level for each of the plurality of lighting states helps to ensure that a clear indication of the state of the operational stage is provided to the user. If instead the brightness level is allowed to vary in a given one of the plurality of lighting states, the change in brightness level may lead to uncertainty as to the exact state of the operational stage. Having the control electronics configured to maintain a static or constant brightness level for each of the plurality of lighting states avoids these drawbacks and helps to ensure that the lighting states are clearly distinguished from one another, thereby being able to identify different points in time in the operational stage.

[0014] Conveniently, the control electronics may be configured to control each of the plurality of light-emitting units to remain in the off state, the first lighting state, or the second lighting state for a predetermined time or until a progression of an operational stage of the aerosol generating device is detected. The predetermined time may be selected to provide a sufficient time for a user to visually detect the off state or the first and second lighting states. By using the detection of a progression of an operational stage of the aerosol generating device as a trigger to change the state of each of the plurality of light-emitting units, the continued presence of the off state, the first lighting state, or the second lighting state may be used as an indication that the operational stage remains unchanged.

[0015] The control electronics may be configured to detect the progression of the operational stages of the aerosol generating device by detecting one or more of a user input, a puff on the device, generation of a predetermined amount of aerosol, or time elapsed after a user input or a puff on the device. The aerosol generating device may be configured to detect a user input, a puff on the device, or generation of a predetermined amount of aerosol through the use of dedicated sensors. Such sensors may include one or more of a temperature sensor, an airflow sensor, a pressure sensor, and a volume sensor. The aerosol generating device may preferably include an electric heating arrangement for heating the aerosol-forming substrate. Advantageously, a change in temperature of the electric heating arrangement over time may be used to detect a puff on the aerosol generating device or generation of a predetermined amount of aerosol. The electric heating arrangement may be a resistive heating arrangement or an inductive heating arrangement. If the electric heating arrangement is a resistive heating arrangement, the change in temperature of the heating arrangement may be determined based on a change in the temperature dependence of the electrical resistance of a component of the heating arrangement.

[0016] The first static brightness level may be more intense than the second static brightness level. In this specification, the terms "first" and "second" are used only to indicate that the first and second brightness levels of the respective first and second lighting states are different from each other, and unless otherwise stated, the terms "first" and "second" do not require that the first static brightness level occurs at an earlier time than the second static brightness level. The difference in intensity of the first and second static brightness levels facilitates clear communication of data regarding the progression of the operation stage to the user. The difference in intensity may be used to indicate the progression of time, or any other parameter indicative of the progression through the operation stage. By way of example, the any other parameter may include one or more of temperature (such as the temperature of an electrical heating arrangement used to heat the aerosol-forming substrate), the cumulative number of puffs applied to the aerosol-generating device over the course of a use session, and the cumulative volume of aerosol emitted from the aerosol-forming substrate over the course of a use session. In a first embodiment, the control electronics may be configured to control each of the lighting units to be in a first lighting state during an earlier portion of the operation stage and in a second lighting state during a later portion of the operation stage. For this first embodiment, the operational phase may be a use session, and the brightness level decreases from a first static brightness level to a second static brightness level over the course of the use session. In a second embodiment, the control electronics may be configured to control each of the lighting units to be in the second lighting state during an earlier portion of the operational phase and in the first lighting state during a later portion of the operational phase. For this second embodiment, the operational phase may be a pre-heat operational phase, in which the temperature of the electrical heating arrangement of the aerosol generating device is increased to a predetermined target temperature and the brightness level increases over the pre-heat phase to indicate the increase in temperature of the electrical heating arrangement.

[0017] The plurality of light emitting units may be in a first illumination state during a first stage of progression through an operational stage of the aerosol generating device. In this manner, a first static brightness level of the first illumination state is associated with the first stage of progression through the operational stage. As an example, the first stage may be a predetermined portion of a use session or a predetermined portion of a pre-heating stage of operation of an electrical heating arrangement of the aerosol generating device.

[0018] The control electronics may be configured to independently control each of the plurality of light-emitting units to be initially in a first lighting state, to be in a second lighting state after the first lighting state, and to be in an off state after the second lighting state while indicating to a user the progression of the operational stages of the aerosol generating device. In this manner, the brightness of each of the plurality of light-emitting units can track the progression through the operational stages. If the first static brightness level is stronger than the second static brightness level, the decrease in brightness from the first lighting state to the second lighting state to the off state provides an efficient method of communicating data related to the progression through the operational stages to a user.

[0019] The control electronics may be configured to change a state of only one of the plurality of light-emitting units of the illumination array at a time in response to detecting a progression of an operational stage of the aerosol generating device. In this manner, a change in the state of only one of the plurality of light-emitting units may convey data to a user regarding progression through a usage session. A change in the state of only one of the plurality of light-emitting units may be a change in one or more of the brightness and color of the light emitted by the light-emitting unit. As described in the preceding paragraph, the control electronics may be configured to detect a progression of an operational stage of the aerosol generating device by detecting one or more of a user input, a puff on the device, generation of a predetermined amount of aerosol, or a time elapsed since a user input or a puff on the device.

[0020] The control electronics may be configured to control each of the plurality of light-emitting units such that the plurality of light-emitting units are in an off state during an n+5th stage of operation of the aerosol generating device.

[0021] The control electronics may be configured to operate the lighting array in two or more color states to control the color of light emitted in each lighting state. In this manner, each lighting state has a color and brightness level, which may further increase the precision and complexity of the data regarding operational progress that can be communicated to a user.

[0022] Advantageously, each light emitting unit is a light emitting diode (LED). The use of light emitting units in LED form is preferred due to the high energy efficiency of LEDs. It is preferred that the aerosol generating device is handheld and includes a power source and is sized to provide portability. 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 unit 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 an aerosol generating device.

[0023] Preferably, the aerosol generating device may further comprise one or more waveguides configured to direct light generated by the plurality of light emitting units to one or more viewing windows of the illumination array. As used herein, the term "waveguide" refers to a structure adapted to guide electromagnetic waves of light. The waveguide may conveniently be in the form of one or more optical fibres or light pipes. Each of the light emitting units is conveniently associated with a corresponding waveguide, such that light emitted from each light emitting unit is transmitted to one or more viewing windows via the corresponding waveguide.

[0024] Advantageously, 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 a supply of electricity from a power source to one or more of the plurality of light emitting diodes under the control of the microcontroller to control each of the light emitting units to be in one of an off state or one of the illuminated states. The control driver may be configured to control one or both of a voltage level or a current level of the electricity supply.

[0025] The plurality of light emitting diodes may additionally include one or more light emitting diodes in a first set configured to emit light of a first color and one or more light emitting diodes in a second set 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, or only the second set, or from a combination of both the first and second sets to control the color of the lighting array. In this manner, the light emitting diode control driver provides control of the color as well as the brightness level of the emitted light for the first and second lighting conditions.

[0026] The lighting array may further include a plurality of viewing windows for transmitting light to a user, and one or more waveguides, each of which may be coupled at a first portion to a respective one of the first and second sets of light emitting diodes, and each of the one or more waveguides may be coupled to a same one of the viewing windows of the lighting array such that the first and second sets of light emitting diodes control the color of light transmitted through the viewing windows.

[0027] Conveniently, the light-emitting diode control driver may be configured to control the supply of electricity from the power source to one or more of the plurality of light-emitting diodes by a type of pulse width modulation having a predetermined resolution to control the brightness of one or more of the plurality of light-emitting diodes in each of the lighting conditions. 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 static 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 may be controlled by the predetermined resolution selected for the light-emitting diode control driver.

[0028] The control electronics is preferably configured to independently control each of the light-emitting units in the off state, the first lighting state, and the second lighting state such that the light emitted by the light-emitting units in the first and second lighting states 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-heat light emission. "Use session light emission" means a light emission indicative of a power source of the aerosol generating device containing sufficient energy to complete a predetermined number of use sessions. "Low energy light emission" means a light emission indicative of a power source of the aerosol generating device containing energy below a predetermined threshold level of energy. "Thermal profile light emission" means 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. "Pause light emission" means a light emission indicative of an aerosol generating device being in a pause mode. "State change light emission" means a light emission indicative of a change in an operational state of the aerosol generating device. "Progression light emission" means a light emission indicative of progression through a use session. "Pre-heating light radiation" means light radiation indicative of the 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 radiation" are outlined in the following paragraphs.

[0029] 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 and the second predetermined energy threshold may correspond to the power source containing sufficient energy to complete multiple use sessions, preferably two use sessions. The control electronics may also be configured to operate the lighting array 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 the lighting array 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 each other. 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 the 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.

[0030] The control electronics may be configured to activate a greater proportion of the lighting array to generate a multiple use session light emission than to generate a single use session light emission.

[0031] The control electronics may be configured to operate a first proportion of the lighting array to generate a single use session light emission in response to a first condition and to operate a second proportion of the lighting array to generate a multiple use session light emission in response to a second condition. The second proportion may form a greater proportion of the length of the lighting array than the first proportion. Preferably, the first proportion of the lighting array may form up to 45-55% of the length of the lighting array and the second proportion of the lighting array may form up to 90-100% of the length of the lighting array.

[0032] The control electronics may be configured to operate the lighting array 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. Preferably, the control electronics may be configured to operate the lighting array 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 may be greater than the first predetermined brightness.

[0033] 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 low energy threshold level of energy, and in response to the determined level of energy being equal to or less than the low energy threshold level of energy, activate the lighting array 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 low energy threshold level of energy. In this way, 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.

[0034] Preferably, the low energy threshold level of energy may be 20% or less of the predetermined energy capacity of the power source.

[0035] The control electronics may be configured to operate the lighting array such that the low energy light emissions have a predetermined color.

[0036] The control electronics may be configured to operate a small percentage of the lighting array to generate low energy light radiation, preferably the small percentage forming less than 15% of the length of the lighting array, or preferably less than 10%, or preferably less than 5%.

[0037] The small percentage may be located at one of the first or second ends of the lighting array.

[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 the illumination array to generate a first thermal profile light emission in response to the selection of the first predefined thermal profile, and to activate the illumination array to generate a second thermal profile light emission in response to the selection of the second predefined thermal profile. The first thermal profile light emission indicates the selection of the first predefined thermal profile. The second thermal profile light emission indicates the selection of the second predefined thermal profile. In this way, a visual indication may be provided to the user as to which of the predefined 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. In addition, the second predetermined thermal profile may be associated with a greater amount of energy being delivered from the power source to the electric heating arrangement over a session of use than the first predetermined thermal profile.

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

[0041] The control electronics may be configured to operate a first proportion of the lighting array 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 the lighting array 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 may define a greater proportion of the length of the lighting array than the first proportion.

[0042] The lighting array may include a plurality of lighting elements, and the control electronics may 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.

[0043] The control electronics may be configured to operate the lighting array such that the first and second thermal profile light emissions differ from one another in one or more of brightness and color. Further, the control electronics may be configured to operate the lighting array such that the first thermal profile light emission has a first predetermined color and the second thermal profile light emission has a second predetermined color. A dominant wavelength of the second thermal profile light emission may be greater in size than a dominant wavelength of the first thermal profile light emission.

[0044] 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 at a first temperature level in the aerosol-generation mode, to control the supply of energy from the power source to the electrical heating arrangement to heat the aerosol-forming substrate at a second temperature level less than the first temperature level in the pause mode in response to a pause signal, and to activate the lighting array 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.

[0045] The aerosol generating device may include a motion sensor for detecting movement of the aerosol generating device. The motion sensor may be coupled to the control electronics. The control electronics may be configured to use the detected movement to trigger a pause signal. The control electronics may be configured to use the detected movement to trigger a pause signal when the detected movement corresponds to a predetermined movement.

[0046] Alternatively, the aerosol generating device may include a motion sensor for detecting a lack of movement of the aerosol generating device. The motion sensor may be coupled to the control electronics. The control electronics may be configured to use the detected lack of movement to trigger a pause signal. A lack of movement of the aerosol generating device may be 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.

[0047] 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.

[0048] The control electronics may be configured to use the detected motion to trigger a pause signal when the detected motion corresponds to a predetermined motion.

[0049] The aerosol generating device may include an orientation sensor for detecting an orientation of the aerosol generating device. The orientation sensor may be 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. 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.

[0050] The aerosol generating device may further comprise a user interface actuatable by a user to initiate the pause mode. Preferably, the user interface may include a button.

[0051] The control electronics may be 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.

[0052] The control electronics may be configured to actuate two spatially distinct portions of the lighting array to generate the suspended light emission, preferably one of the two spatially distinct portions being located at a first end of the lighting array and the other of the two spatially distinct portions being located at a second end of the lighting array.

[0053] The control electronics may be configured to activate and deactivate the spatially distinct portions sequentially to generate the suspended light emission. Additionally, the control electronics may be configured to activate and deactivate the spatially distinct portions out of phase with each other to generate the suspended light emission.

[0054] The control electronics may be configured to actuate spatially distinct portions 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.

[0055] The control electronics may be configured to operate all or a portion of the lighting array to generate a pause light emission such that a central portion of the lighting array has a greater brightness than a remainder of the lighting array. The control electronics may be configured to operate all or a portion of the lighting array to generate a pause light emission such that a brightness of the lighting array decreases progressively moving from the central portion towards the first and second ends of the lighting array.

[0056] 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 the lighting array to generate a state change light emission. The state change light emission indicates 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.

[0057] The change in operating state may include activation of the device from an off mode, or reactivation of the device from a paused mode. 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-generation mode. The paused 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.

[0058] The control electronics may be configured to progressively activate the lighting array over a predetermined period of time to progressively increase the activation length of the lighting array over a predetermined period of time for the state-changing light emission.

[0059] The control electronics may be configured to activate all or a portion of the lighting array to progressively increase brightness over a predetermined period of time for the state-changing light emission. The control electronics may be configured to activate all or a portion of the lighting array such that at the beginning of the predetermined period, the brightness of the actuated portion of the lighting array progressively decreases with distance away from a center of the actuated portion of the lighting array toward the first and second ends. The brightness may be progressively increased over the predetermined period of time such that at the end of the predetermined period, the actuated portion of the lighting array has a uniform brightness over the length of the actuated portion.

[0060] The control electronics may be configured to activate all or a portion of the lighting array such that the brightness of the activated portion of the lighting array is symmetric about the center of the activated portion over a predetermined period of time.

[0061] Conveniently, the progression of the operational stages of the aerosol generating device is a progression of a usage session, and the device may further comprise a power source coupled to 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 usage session to heat the aerosol-forming substrate, to determine the progression through the usage session by reference to a parameter indicative of the progression through the usage session, and to operate the lighting array to generate a progression light radiation that varies as a function of the progression through the usage session, such that the progression light radiation is indicative of the progression through the usage session. In this way, a visual indication of the progression through the usage session may be provided to the user.

[0062] 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.

[0063] 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.

[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 number of puffs reaches a predetermined maximum number of puffs.

[0065] 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.

[0066] The control electronics may be configured to activate all or a majority of the lighting array at the beginning of a use session and progressively shut down the lighting array to progressively reduce the length of activation of the lighting array as the use session progresses. The control electronics may be configured such that no light is emitted from the lighting array upon completion of the use session.

[0067] The lighting array may include spatially distinct first and second portions corresponding to respective first and second use sessions. The control electronics may be configured to activate a first portion of the lighting array at the start of a first use session and progressively deactivate the first portion of the lighting array to progressively reduce the activation length of the first portion as the first use session progresses, and to activate a second portion of the lighting array at the start of a second use session and progressively deactivate the second portion of the lighting array to progressively reduce the activation length of the second portion as the second use session progresses. The control electronics may preferably be configured such that upon completion of the first and second use sessions, no light is emitted from the respective spatially distinct first and second portions of the lighting array.

[0068] The spatially distinct first and second portions may each extend between 45% and 50% of the length of the lighting array.

[0069] The aerosol generating device may conveniently further comprise a power source coupled to the control electronics. The aerosol generating device may also 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 the lighting array to generate a pre-heating light emission that varies with 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.

[0070] 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.

[0071] The at least one characteristic may be an equivalent resistance of the induction heating arrangement or may be an inductance of the induction heating arrangement.

[0072] The control electronics may be configured to operate the lighting array such that different parts of the lighting array vary in brightness over time and relative to each other, and the brightness of the lighting array increases progressively over a pre-heating phase.

[0073] The control electronics may be configured to operate the illumination array such that a dominant wavelength of the pre-heating light radiation is progressively increased over the pre-heating stage.

[0074] The control electronics may be configured to operate the lighting array to progressively increase the length of activation of the lighting array as one progresses through the pre-heat stage.

[0075] The control electronics may be configured to operate the lighting array during or upon completion of the preheat phase such that the brightness of the activated length of the lighting array increases progressively with increasing distance between first and second opposing ends of the activated length.

[0076] The control electronics may be configured to operate the lighting array 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 actuated length of the lighting array. 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 end defines a blue color of the preheat light radiation and the second opposing end defines a red color of the preheat light radiation.

[0077] The control electronics may be configured such that the lighting array has a uniform brightness along the length of the lighting array upon completion of the pre-heating stage.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] The aerosol-forming substrate may comprise a single aerosol former, or the aerosol-forming substrate may comprise a combination of two or more aerosol formers. EXAMPLES

[0088] 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.

[0089] Example 1: An aerosol generating device for heating an aerosol-forming substrate to generate an inhalable aerosol during a usage session, the aerosol generating device comprising control electronics and at least one lighting array including a plurality of light-emitting units, the control electronics configured to independently control each of the plurality of light-emitting units in at least i) an off state in which the light-emitting units do not emit light, ii) a first lighting state in which the light-emitting units emit light at a first static brightness level, and iii) a second lighting state in which the light-emitting units emit light at a second static brightness level different from the first static brightness level, and the control electronics configured to control each of the light-emitting units to be in one of the off state, the first lighting state, and the second lighting state so as to indicate to a user a progression of operational stages of the aerosol generating device. Example 2: 2. An aerosol generating device according to embodiment 1, wherein the illumination array is substantially linear. Example 3: An aerosol generating device according to any one of embodiments 1 or 2, wherein the lighting array extends between a first end and a second end of the lighting array. Example 4: An aerosol generating device according to any one of Examples 1 to 3, wherein the progression of operational stages of the aerosol generating device is the progression of a usage session. Example 5: An aerosol generating device according to any one of Examples 1 to 4, wherein the control electronics is configured to independently control each of a plurality of light-emitting units of the lighting array in a plurality of lighting states, and in each of the plurality of display states, each light-emitting unit emits light at a different static brightness level. Example 6: An aerosol generating device according to Example 5, wherein in each of a plurality of lighting states, the brightness level of the light emitted from each light-emitting unit is static, such that the brightness level remains substantially constant until the light-emitting unit leaves that lighting state. Example 7: An aerosol generating device according to any one of Examples 1 to 6, wherein the control electronics is configured to control each of the multiple light-emitting units to remain in an off state, a first lighting state, or a second lighting state for a predetermined time or until a progression of an operational stage of the aerosol generating device is detected. Example 8: An aerosol generating device according to Example 7, wherein the control electronics is configured to detect the progression of an operational stage of the aerosol generating device by detecting one or more of a user input, a puff on the device, generation of a predetermined amount of aerosol, or time elapsed after a user input or a puff on the device. Example 9: An aerosol generating device according to any one of Examples 1 to 8, wherein the first static luminance level is stronger than the second static luminance level. Example 10: An aerosol generating device according to any one of Examples 1 to 9, wherein the plurality of light emitting units are in a first illumination state during a first stage of progression through an operational stage of the aerosol generating device. Example 11: An aerosol generating device according to any one of Examples 1 to 10, wherein the control electronics is configured to independently control each of the plurality of light-emitting units to be initially in a first lighting state, to be in a second lighting state after the first lighting state, and to be in an off state after the second lighting state, while indicating to a user the progression of operational stages of the aerosol generating device. Example 12: An aerosol generating device according to any one of Examples 1 to 11, wherein the control electronics is configured to change the state of only one of the multiple light-emitting units of the lighting array at a time in response to detecting a progression of an operational stage of the aerosol generating device. Example 13: An aerosol generating device according to Example 12, wherein the control electronics is configured to detect the progression of an operational stage of the aerosol generating device by detecting one or more of a user input, a puff on the device, generation of a predetermined amount of aerosol, or time elapsed since a user input or a puff on the device. Example 14: An aerosol generating device according to any one of Examples 1 to 13, wherein a plurality of light-emitting units are in an off state during the n+5th stage of operation of the aerosol generating device. Example 15: An aerosol generating device according to any one of Examples 1 to 14, wherein the control electronics is configured to operate the lighting array in two or more color states to control the color of light emitted in each lighting state. Example 16: The aerosol generating device according to any one of Examples 1 to 15, wherein each light-emitting unit is a light-emitting diode. Example 17: An aerosol generating device according to any one of Examples 1 to 16, further comprising one or more waveguides configured to direct light generated by the multiple light-emitting units to one or more display windows of the lighting array. Example 18: An aerosol generating device according to any one of Examples 1 to 17, wherein each of the plurality of light-emitting units includes a light-emitting diode, and the control electronics includes a light-emitting diode control driver and a separate microcontroller, and the control driver is configured to control the supply of electricity from a power source to one or more of the plurality of light-emitting diodes under the control of the microcontroller so as to control each of the light-emitting units to be in one of an off state or an illuminated state. Example 19: An aerosol generating device according to Example 18, wherein the plurality of light-emitting diodes includes 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, and the light-emitting diode control driver is configured to operate one or more of the light-emitting diodes from only the first set, or only the second set, or from a combination of both the first set and the second set to control the color of the lighting array. Example 20: An aerosol generating device according to Example 19, wherein the lighting array includes a plurality of display windows for transmitting light to a user and further includes one or more waveguides, each of the one or more waveguides being connected at a first portion to a respective one of the first and second sets of light emitting diodes, and each of the one or more waveguides being connected to the same one of the display windows of the lighting array such that the first and second sets of light emitting diodes control the color of light transmitted through the display windows. Example 21: An aerosol generating device according to any one of Examples 18 to 20, wherein the light-emitting diode control driver is configured to control the supply of electricity from the power source to one or more of the plurality of light-emitting diodes by a type of pulse width modulation having a predetermined resolution to control the brightness of one or more of the plurality of light-emitting diodes in each of the lighting conditions. Example 22: An aerosol generating device according to any one of Examples 1 to 21, wherein the control electronics is configured to independently control each of the light-emitting units in an off state, a first lighting state, and a second lighting state, so that the light emitted by the light-emitting units in the first and second lighting states is one or more of a usage 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. Example 23: The aerosol generating device according to any one of Examples 1 to 22, further comprising a power source coupled to the control electronics, the control electronics being configured to determine a level of energy contained in the power source and compare the determined level of energy with 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 multiple use sessions, preferably two use sessions, and in response to a first state in which the determined level of energy is sufficient to complete a single use session, actuate the lighting array 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, actuate the lighting array to generate multiple use session light emissions, the single use session light emission and the multiple use session light emissions being different from each other, the single use session light emission indicating a first state and the multiple use session light emissions indicating a second state. Example 24: An aerosol generating device according to Example 23, wherein the control electronics is configured to activate a greater proportion of the lighting array to generate a multiple use session light radiation than to generate a single use session light radiation. Example 25: An aerosol generating device according to any one of Examples 23 or 24, wherein the control electronics is configured to operate a first proportion of the lighting arrays to generate a single use session light radiation in response to a first state, and to operate a second proportion of the lighting arrays to generate multiple use session light radiation in response to a second state. Example 26: An aerosol generating device according to Example 25, wherein a first proportion of the lighting array forms up to 45-55% of the length of the lighting array, and a second proportion of the lighting array forms up to 90-100% of the length of the lighting array. Example 27: An aerosol generating device according to any one of Examples 23 to 26, wherein the control electronics is configured to operate the lighting array 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 28: An aerosol generating device according to Example 27, wherein the control electronics is configured to operate the lighting array 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 29: An aerosol generating device according to any one of Examples 1 to 28, further comprising a power source coupled to the control electronics, wherein the control electronics is configured to determine a level of energy contained in the power source, compare the determined level of energy with a low energy threshold level of energy, and in response to the determined level of energy being below the low energy threshold level of energy, operate the lighting array to generate low energy light radiation, the low energy light radiation indicating that the determined level of energy is below the low energy threshold level of energy. Example 30: 30. An aerosol generating device according to embodiment 29, wherein the low energy threshold level of energy is 20% or less of the predetermined energy capacity of the power source. Example 31: An aerosol generating device according to any one of Examples 29 or 30, wherein the control electronics is configured to operate the lighting array so that the low energy light radiation has a predetermined color. Example 32: An aerosol generating device according to any one of Examples 29 to 31, wherein the control electronics is configured to activate a small proportion of the lighting array to generate low energy light radiation. Example 33: An aerosol generating device according to embodiment 32, wherein the small proportion forms less than 15% of the length of the lighting array, or preferably less than 10%, or preferably less than 5%. Example 34: An aerosol generating device according to any one of Examples 32 or 33, wherein the small proportion is located at one of the first end or the second end of the lighting array. Example 35: An aerosol generating device according to any one of Examples 1 to 34, further comprising a power source coupled to the control electronics, wherein the control electronics receives 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, and configured to 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, operate the illumination array to generate a first predetermined thermal profile light radiation, and in response to the selection of the second predetermined thermal profile, operate the illumination array to generate a second thermal profile light radiation, wherein the first thermal profile light radiation indicates the selection of the first predetermined thermal profile and the second thermal profile light radiation indicates the selection of the second predetermined thermal profile. Example 36: 36. An aerosol generating device according to example 35, wherein the second predetermined thermal profile has a greater intensity than the first predetermined thermal profile. Example 37: An aerosol generating device according to Example 36, 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 38: An aerosol generating device according to any one of Examples 35 to 37, 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 39: An aerosol generating device according to Example 38, 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 40: An aerosol generating device according to any one of Examples 35 to 39, wherein the control electronics is configured to activate a first proportion of the lighting array to generate a first thermal profile light radiation in response to selection of a first predetermined thermal profile, and to activate a second proportion of the lighting array 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 41: An aerosol generating device according to example 40, wherein the second proportion defines a greater proportion of the length of the illumination array than the first proportion. Example 42: An aerosol generating device according to any one of Examples 35 to 41, wherein the lighting array includes 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 to generate the first thermal profile light radiation. Example 43: An aerosol generating device according to any one of Examples 35 to 42, wherein the control electronics is configured to operate the lighting array so that the first and second thermal profile light emissions differ from each other in one or more of brightness and color. Example 44: An aerosol generating device according to Example 43, wherein the control electronics is configured to operate the lighting array 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 45: An aerosol generating device according to any one of Examples 1 to 44, 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 to heat the aerosol-forming substrate to a first temperature level in the aerosol generating 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 operate the lighting array to generate a pause light emission, the pause light emission indicating that the aerosol generating device is in the pause mode. Example 46: An aerosol generating device according to Example 45, 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.

[0090] Example 47: An aerosol generating device according to Example 45, 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 48: An aerosol generating device according to Example 47, 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 49: An aerosol generating device according to Example 45, further comprising a user interface and / or a puff detection mechanism for detecting puffs at the device, and the control electronics 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 50: An aerosol generating device according to example 46, wherein the control electronics is configured to use the detected movement to trigger a pause signal when the detected movement corresponds to a predetermined movement. Example 51: An aerosol generating device according to any one of Examples 45 to 50, 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 change in the detected orientation for a predetermined time, to trigger a pause signal. Example 52: An aerosol generating device according to Example 51, 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 53: The aerosol generating device according to any one of Examples 45 to 52, 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 54: An aerosol generating device according to Example 53, 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 55: An aerosol generating device according to any one of Examples 45 to 54, wherein the control electronics is configured to activate two spatially distinct portions of the lighting array to generate a suspended light emission. Example 56: An aerosol generating device according to Example 55, wherein one of the two spatially separate portions is positioned at a first end of the lighting array and the other of the two spatially separate portions is positioned at a second end of the lighting array.

[0091] Example 57: An aerosol generating device according to any one of Examples 55 or 56, wherein the control electronics is configured to sequentially activate and deactivate spatially distinct portions to generate a suspended optical emission. Example 58: An aerosol generating device according to example 57, wherein the control electronics are configured to activate and deactivate spatially distinct portions out of phase with each other to generate suspended optical radiation. Example 59: An aerosol generating device according to any one of Examples 55 to 58, wherein the control electronics is configured to actuate spatially distinct portions to vary the brightness or color of the suspended light radiation over time, thereby varying at least one of the brightness or wavelength over time. Example 60: An aerosol generating device according to any one of Examples 45 to 54, wherein the control electronics is configured to operate all or a portion of the lighting array to generate a suspended light emission such that a central portion of the lighting array has greater brightness than the remaining portions of the lighting array. Example 61: An aerosol generating device according to Example 60, wherein the control electronics is configured to activate all or a portion of the lighting array to generate a paused light emission such that the brightness of the lighting array gradually decreases moving from a central portion of the lighting array toward the first and second ends. Example 62: An aerosol generating device according to any one of Examples 1 to 61, further comprising a power source coupled to the 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 the lighting array to generate state change light radiation, the state change light radiation indicating receipt of an input for changing the operating state. Example 63: 63. An aerosol generating device according to Example 62, 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 64: An aerosol generating device according to Example 63, 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 generating 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 65: An aerosol generating device according to any one of Examples 62 to 64, wherein the control electronics is configured to gradually activate the lighting array over a predetermined period of time to gradually increase the activation length of the lighting array over a predetermined period of time for the state-changing light emission. Example 66: An aerosol generating device according to any one of Examples 62 to 65, wherein the control electronics is configured to operate all or a portion of the lighting array to gradually increase brightness over a predetermined period of time for state-changing light emission. Example 67: An aerosol generating device according to Example 66, wherein the control electronics are configured to activate all or a portion of the lighting array such that at the beginning of a predetermined period, the brightness of the activated portion of the lighting array gradually decreases with distance from the center of the activated portion of the lighting array toward the first and second ends, and the brightness gradually increases over the predetermined period such that at the end of the predetermined period, the activated portion of the lighting array has a uniform brightness over the length of the activated portion. Example 68: An aerosol generating device according to any one of Examples 66 or 67, wherein the control electronics is configured to activate all or a portion of the lighting array so that the brightness of the activated portion of the lighting array is symmetrical about the center of the activated portion over a predetermined period of time. Example 69: An aerosol generating device according to any one of Examples 1 to 68, wherein the progression of the operational stages of the aerosol generating device is the progression of a usage session, and the device further comprises 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 the usage session to heat the aerosol forming substrate, determine the progression through the usage session by referring to a parameter indicative of the progression through the usage session, and operate the lighting array to generate progressing light radiation that varies in accordance with the progression through the usage session such that the progressing light radiation is indicative of the progression through the usage session. Example 70: An aerosol generating device according to Example 69, 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 71: An aerosol generating device according to Example 70, wherein the control electronics is 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 72: An aerosol generating device according to Example 71, 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 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. Example 73: An aerosol generating device according to any one of Examples 71 or 72, 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 74: An aerosol generating device according to any one of Examples 69 to 73, wherein the control electronics are configured to activate all or a majority of the lighting array at the beginning of a use session and progressively deactivate the lighting array to progressively reduce the length of activation of the lighting array as the use session progresses. Example 75: An aerosol generating device according to Example 74, wherein the control electronics are configured to prevent light from being emitted from the lighting array upon completion of a usage session. Example 76: An aerosol generating device according to any one of Examples 69 to 75, wherein the lighting array includes spatially separate first and second portions corresponding to respective first and second use sessions, and the control electronics are configured to activate a first portion of the lighting array at the start of a first use session and progressively deactivate the first portion of the first lighting array to progressively reduce the activated length of the first portion as the first use session progresses, and to activate a second portion of the lighting array at the start of a second use session and progressively deactivate the second portion of the lighting array to progressively reduce the activated length of the second portion as the second use session progresses. Example 77: An aerosol generating device according to Example 76, wherein the control electronics is configured such that upon completion of the first and second use sessions, no light is emitted from the respective spatially distinct first and second portions of the lighting array. Example 78: An aerosol generating device according to any one of Examples 76 or 77, wherein the spatially distinct first and second portions each extend 45% to 50% of the length of the illumination array. 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, wherein the aerosol generating device is configured to receive an aerosol generating article comprising an aerosol-forming substrate, and the control electronics is 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 the lighting array to generate pre-heating light radiation that varies 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 lighting array such that different portions of the lighting array vary in brightness over time and relative to each other, and the brightness of the lighting array increases gradually over 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 illumination array so that the dominant wavelength of the preheating light radiation increases progressively throughout the preheating stage. Example 84: An aerosol generating device according to any one of Examples 79 to 83, wherein the control electronics is configured to activate the lighting array to progressively increase the activation length of the lighting array as the device progresses through the pre-heating stage. Example 85: An aerosol generating device according to any one of Examples 79 to 84, wherein the control electronics is configured to operate the lighting array during or upon completion of the preheating phase such that the brightness of the activated length of the lighting array increases progressively with increasing distance between the first and second opposing ends of the activated length. Example 86: An aerosol generating device according to any one of Examples 79 to 85, wherein the control electronics is configured to operate the lighting array 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 actuated length of the lighting array. Example 87: An aerosol generating device according to example 86, 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 88: An aerosol generating device according to any one of Examples 79 to 87, wherein the control electronics are configured such that upon completion of the pre-heating phase, the lighting array has uniform brightness along the length of the lighting array. [Brief description of the drawings]

[0092] The embodiments will now be further described with reference to the following figures:

[0093] [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 is a first example showing the operation of an illumination array provided on the aerosol generating device of FIGS. 1-4 as it progresses through a usage session. [Figure 6] FIG. 6 is a second example showing the operation of an illumination array provided on the aerosol generating device of FIGS. 1-4 as it progresses through a usage session. [Figure 7] FIG. 7 is a third example showing the operation of an illumination array provided on the aerosol generating device of FIGS. 1-4 as it progresses through a usage session. [Figure 8] FIG. 8 is a fourth example showing the operation of an illumination array provided on the aerosol generating device of FIGS. 1-4 progressing through a pause mode of operation. [Figure 9] FIG. 9 is a fifth example showing the operation of an illumination array provided on the aerosol generating device of FIGS. 1-4 progressing through a pause mode of operation. [Figure 10] FIG. 10 is a sixth example showing the operation of an illumination array provided on the aerosol generating device of FIGS. 1-4 progressing through a pause mode of operation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0094] 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).

[0095] 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 inhaled by the user, similar to a conventional cigarette.

[0096] The lighting array 60 is incorporated within the housing 20 of the aerosol generation device 10. (See FIG. 1). The lighting array 60 is formed of a linear arrangement of six light emitting diodes 61 a...f extending between a first end 62 and a second end 63 of the lighting array. The lighting array 60 also has a viewing window 64 which forms part of the exterior surface of the housing 20 and is optically transparent. As will be explained in more detail below, light generated by each of the light emitting diodes 61 a...f is directed towards the viewing window 64 so as to be visible to a user of the aerosol generation device 10 during use.

[0097] The battery 11 and the microcontroller 12 are coupled to each other and are 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 element 40 and the illumination control driver 13. The microcontroller 12 and the illumination control driver 13 collectively form the control electronics section 100 of the aerosol generating device 10. The illumination control driver 13 is coupled to each of the light emitting diodes 61a...f. Waveguides 65...f are provided between the light emitting diodes 61a...f and the display window 64. Each of the waveguides 65a...f is associated with a respective one of the light emitting diodes 61a...f such that, in use, each waveguide functions to direct light generated by one of the associated light emitting diodes towards the display window 64. The waveguides 65a...f are in the form of individual lengths of optical fibre.

[0098] The memory module 12a contains 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 supply of electricity to each of the light-emitting diodes 61a...f, such that each light-emitting diode emits light 66a...f at one of a plurality of individual static brightness levels under the control of the lighting control driver (see FIG. 4). The three different forms of cross-hatching used in FIG. 4 for the light 66a...f generated by different ones of the light-emitting diodes 61a...f represent three different static brightness levels.

[0099] 4, the brightness of the lighting array 60 is symmetric about the center of the lighting array, such that the two centrally located light emitting diodes 61c, 61d are independently controlled by the lighting control driver 13 to emit light at a first predetermined static brightness level, the adjacent light emitting diodes 61b, 61e are independently controlled to emit light at a second predetermined static brightness level, and the outermost light emitting diodes 61a, 61f are independently controlled to emit light at a third predetermined static brightness level.

[0100] 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.

[0101] The temperature of the heater element 40 is raised in a pre-heating stage from ambient temperature to a predetermined target temperature for heating the aerosol-forming substrate 31 according to a selected predetermined thermal profile. Once the predetermined 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 generated aerosol 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 predetermined 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 alternative embodiments, 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.

[0102] 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.

[0103] In the various embodiments shown in Figures 5-7, the lighting control driver 13 individually controls the supply of electricity to each of the light emitting diodes 61a...f during the course of a usage session to provide the user with an indication of their progress through the usage session.

[0104] For the embodiment of FIG. 5, the light emitting diodes 61a...c form the top half of the lighting array 60, and the light emitting diodes 61d...f form the bottom half of the lighting array. The light emitting diodes in the top and bottom halves of the lighting array 60 each extend approximately 50% of the length of the lighting array. The lighting control driver 13 is configured to control the supply of energy from the battery 11 to progressively decrease, during the course of a usage session, the static brightness level of the light emitted by each of the light emitting diodes 61a...c in the top half of the lighting array 60, starting with the top light emitting diode 61a. As shown in the legend in FIG. 5, the light emitting diodes 61a...c are controlled by the lighting control driver 13 to emit light having one of three predefined static brightness levels or to be in a rest state where no light is emitted. The predefined static brightness levels are indicated as levels 3, 2, and 1 in order of decreasing brightness, with the rest state being numbered as level 0. At the start of a use session, all of the light emitting diodes 61 a...c in the top half of the lighting array 60 are controlled to emit light having a maximum static brightness level, i.e. level 3. Over the course of a use session, the lighting control driver 13 regulates the supply of energy from the battery 11 to each of the light emitting diodes 61 a...c so as to progressively reduce the static brightness level of the light emitted by the light emitting diodes 61 a...c from level 3 to level 2 to level 1 and finally to level 0. The effect of the lighting control driver 13 is to progressively shut down the light emitting diodes 61 a...c in the top half of the lighting array 60 and progressively reduce the length of activation of the top half of the lighting array as it progresses through the use session. At the end of the use session, all of the light emitting diodes 61 a...c in the top half of the lighting array are in a shut down state, i.e. level 0 (see FIG. 5(e)). For the duration of this use session, the light emitting diodes 61 d...f in the bottom half of the lighting array 60 remain shut down at brightness level 0.

[0105] In another embodiment (not shown) in which the user starts a second use session, the light-emitting diodes 61d...f forming the lower half of the lighting array 60 are controlled by the lighting control driver 13 in a similar manner as the light-emitting diodes 61a...c of the upper half of the lighting array for the previous use session. In this context, the second use session follows the previous use session and is powered by the energy remaining in the battery 11 after the previous use session. The battery 11 is not recharged between the previous use session and the second use session. Thus, at the start of the second use session, all of the light-emitting diodes 61d...f in the lower half of the lighting array 60 are controlled to emit light having a maximum static brightness level, i.e. level 3. In the course of the use session, the lighting control driver 13 adjusts the supply of energy to each of the light-emitting diodes 61d...f so as to progressively decrease the static brightness level of the light emitted by the light-emitting diodes 61d...f, starting from the light-emitting diode 61d, from level 3 to level 0. At the end of the second use session, all of the light-emitting diodes 61d...f in the lower half of the lighting array are in a stopped state, i.e. level 0. For the duration of this second use session, the light emitting diodes 61a...c in the top half of the lighting array remain switched off at brightness level 0.

[0106] The embodiment of FIG. 6 differs from that of FIG. 5 in that the static brightness levels of all of the light-emitting diodes 61 a...f forming the entire length of the lighting array 60 are progressively decreased over a usage session. A further difference of the embodiment of FIG. 6 with respect to the embodiment of FIG. 5 is that the light-emitting diodes 61 a...f are controlled by the lighting control driver 13 to emit light having one of two (instead of three) predefined static brightness levels (shown in FIG. 6 as level 2 and level 1 in order of decreasing brightness) or to be in a rest state in which no light is emitted (shown in FIG. 6 as level 0). At the start of a usage session, all of the light-emitting diodes 61 a...c in the upper half of the lighting array 60 are controlled by the lighting control driver 13 to emit light having the maximum static brightness level, i.e. level 2. As shown in FIGS. 6(a)-6(h), in the course of a usage session, the lighting control driver 13 adjusts the supply of energy to each of the light-emitting diodes 61 a...f to progressively decrease the static brightness level of the light emitted by the light-emitting diodes 61 a...f from level 2 to level 1 and finally to level 0. The effect of the lighting control driver 13 is to progressively deactivate the light emitting diodes 61 a...f over the entire length of the lighting array 60, progressively reducing the activated length of the lighting array as one progresses through the usage session. At the end of the usage session, all of the light emitting diodes 61 a...f of the lighting array are in the deactivated state, i.e. at level 0 (see Figure 6(h)).

[0107] The embodiment of Fig. 7 shares the characteristic of the embodiment of Fig. 6 in using all of the light emitting diodes 61a...f forming the entire length of the lighting array 60 to provide an indication of progress through a usage session. Each of the light emitting diodes 61a...f is controlled by the lighting control driver 13 to emit light having one of seven predefined static brightness levels (shown in Fig. 7 as levels 7, 6, 5, 4, 3, 2, and 1 in order of decreasing brightness) or to a rest state in which no light is emitted (shown in Fig. 7 as level 0). At the start of a usage session, all of the light emitting diodes 61a...f are activated by the lighting control driver 13 to each emit light at a different one of the predefined static brightness levels (see Fig. 7(a)), with the brightness levels decreasing progressively along the length of the lighting array from the light emitting diode 61a (emitting light at brightness level 7) to the light emitting diode 61f (emitting light at brightness level 1). As shown in Figures 7(a)-7(h), over the course of a use session, the lighting control driver 13 adjusts the supply of energy to each of the light emitting diodes 61a...f such that at a given moment only one of the light emitting diodes emits light at a static brightness level higher than the remaining light emitting diodes, this single light emitting diode being referred to as the "peak brightness light emitting diode". As one progresses through the use session, a different one of the light emitting diodes 61a...f becomes the peak brightness light emitting diode, which in effect moves down the length of the lighting array 60 over the use session. The brightness levels of the remaining light emitting diodes gradually decrease with distance from any one light emitting diode at the peak brightness. However, the lighting control driver 13 also operates to adjust the supply of energy to each of the light emitting diodes 61a...f such that as one progresses through the use session, the overall brightness level of the light emitted from the lighting array 60 progressively decreases. At the end of the use session, all of the light emitting diodes 61a...f of the lighting array are at rest, i.e. at level 0 (see Figure 7(h)).

[0108] In various embodiments shown in Figures 8-10, the illumination control driver 13 individually controls the supply of energy to each of the light emitting diodes 61a...f during the pause mode of operation of the aerosol generating device 10. For the embodiments shown and described, the pause mode of operation is activated (and subsequently deactivated) by the user pressing the user button 50. However, in alternative embodiments (not shown), an alternative user interface may be provided with which the user may interact to activate (and subsequently deactivate) the pause mode. Such an alternative user interface may be in the form of a touch sensitive panel with which the user may engage a finger to activate and deactivate the pause mode, the touch sensitive panel being coupled to the microcontroller 12. Alternatively, the alternative user interface may include a motion or orientation sensor coupled to the microcontroller 12, where movement or orientation of the device 10 in a predetermined manner is detected by the sensor and serves as a means for activating and deactivating the pause mode. When the pause mode is activated, the microcontroller 12 regulates the supply of energy from the battery to the heater element 40 to reduce the temperature level of the heater element below the temperature at which aerosol is released from the aerosol-forming substrate 31.

[0109] For the embodiment of FIG. 8, the lighting control driver 13 is configured to control the supply of energy from the battery 11 to the light emitting diodes 61a...f of the lighting array 60 so as to vary the static brightness levels of the light emitted from the spatially distinct light emitting diodes 61a, 61f located at both ends 62, 63 of the lighting array 60. As shown in the legend of FIG. 8, the light emitting diodes 61a, 61f are controlled by the lighting control driver 13 to emit light having one of two predefined static brightness levels or to be in a deactivated state where no light is emitted. In the legend of FIG. 8, the predefined static brightness levels are numbered as levels 2, and 1 in order of decreasing brightness, and the deactivated state is numbered as level 0. FIGS. 8(a)-8(e) show how the lighting control driver 13 controls the brightness of the light generated by the light emitting diodes 61a, 61f over a single cycle. This cycle is repeated as long as the aerosol generating device 10 remains in the pause mode. At the beginning of a usage session, the light-emitting diodes 61a, 61f are controlled to emit light having a maximum static brightness level, i.e. level 2 (see FIG. 8(a)). The lighting control driver 13 then adjusts the supply of energy to the light-emitting diodes 61a, 61f to emit light having a lower static brightness level, i.e. level 1 (see FIG. 8(b)). The lighting control driver 13 then adjusts the supply of energy to both light-emitting diodes 61a, 61f to deactivate both light-emitting diodes, i.e. to level 0 (see FIG. 8(c)). FIGS. 8(d) and 8(e) show how the static brightness level of the light emitted by the light-emitting diodes 61a, 61f then increases progressively back to level 1 and then back to level 2. Throughout the period or cycle represented by FIGS. 8(a)-8(e), the light-emitting diodes 61b...e located between the light-emitting diodes 61a, f remain in the deactivated state, i.e. to level 0. For the embodiment of Figures 8(a)-8(e), the brightness level of light emitting diode 61a is adjusted over a cycle to be in phase with and match the brightness level of light emitting diode 61f.

[0110] The embodiment of Fig. 9 differs from that of Fig. 8 in that the light emitting diodes 61a, 61f located at both ends 62, 63 of the lighting array 60 are adjusted to be out of phase with each other over a cycle. Thus, when the light emitting diode 61a is controlled by the lighting control driver 13 to emit light having a predetermined static brightness level 2, the light emitting diode 61f located at the opposite end of the lighting array 61 is instead controlled to be in a deactivated state. In the middle of the cycle (as represented in Fig. 9(c)), the opposite applies for the light emitting diode 61f controlled to emit light having a predetermined static brightness level 2 and the light emitting diode 61a deactivated.

[0111] For the embodiment of Fig. 10, the lighting control driver 13 controls the supply of energy from the battery 11 to adjust the static brightness level of each of the light-emitting diodes 61a...f while the aerosol generating device 10 remains in the pause mode of operation. The lighting control driver 13 functions to control the light-emitting diodes 61a...f to emit light having one of two predefined static brightness levels or to be in a stopped state. In the legend of Fig. 10, the predefined static brightness levels are numbered as levels 2, and 1 in order of decreasing brightness, and the stopped state is numbered as level 0. Figs. 10(a)-10(g) show how the lighting control driver 13 controls the brightness of the light emitted by the light-emitting diodes 61a...f over a predefined period of time while the device 10 remains in the pause mode. When the pause mode begins, the lighting control driver 13 adjusts the brightness levels of the light emitted by the light emitting diodes 61a...f according to Fig. 10(a) such that the top light emitting diode 61a emits light at the maximum static brightness level (i.e. level 2), the adjacent light emitting diode 61b emits light at a lower static brightness level (i.e. level 1), and all of the remaining light emitting diodes 61c...f are in a stopped state (i.e. level 0). Over a predetermined period of time, the lighting control driver 13 adjusts the supply of energy to the light emitting diodes 61a...f such that a single or adjacent pair of the light emitting diodes 61a...f emits light at the peak static brightness level (i.e. level 2). As the predetermined period progresses, different single ones or adjacent pairs of the light emitting diodes 61a...f emit a bar of light at the peak static brightness level (i.e. level 2). The bar of light at the peak static brightness level effectively moves down the length of the lighting array across Figures 10(a)-10(e) and then moves back up along the lighting array across Figures 10(f) and 10(g) until it is centered on the lighting array as shown in Figure 10(g). The brightness levels of the remaining light emitting diodes progressively decrease with increasing distance from the one of the light emitting diodes that produces the bar of light at the peak static brightness level.At the end of the predetermined period covered by Figures 10(a)-10(g), the intensity of the light emitted by the lighting array 60 is symmetric about the centre of the lighting array.

[0112] 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 a use session, the aerosol generating device comprising: control electronics; and at least one lighting array including a plurality of light-emitting units, wherein the control electronics are configured to independently control each of the plurality of light-emitting units in at least i) an off state in which the light-emitting unit does not emit light, ii) a first lighting state in which the light-emitting unit emits light at a first static luminance level, and iii) a second lighting state in which the light-emitting unit emits light at a second static luminance level different from the first static luminance level, and the control electronics are configured to control each of the light-emitting units to be in one of the off state, the first lighting state, and the second lighting state so as to indicate to the user the progress of the operating phase of the aerosol generating device, wherein the progress of the operating phase of the aerosol generating device is the progress of the use session. An aerosol generating device.

2. The aerosol generating device according to claim 1, wherein the lighting array extends between a first end and a second end of the lighting array.

3. The aerosol generating device according to claim 1, wherein the control electronics are configured to independently control each of the plurality of light-emitting units of the lighting array in a plurality of lighting states, and in each of the plurality of lighting states, each light-emitting unit emits light at a different static luminance level.

4. The aerosol generating device according to claim 1, wherein the control electronics are configured to control each of the plurality of light-emitting units to remain in the off state, the first lighting state, or the second lighting state for a predetermined time or until the progress of the operating phase of the aerosol generating device is detected.

5. The aerosol generating device according to claim 1, wherein the first static luminance level is stronger than the second static luminance level.

6. The aerosol generating device according to claim 1, wherein the plurality of light-emitting units are in the first lighting state during a first stage of the progress through the operating phase of the aerosol generating device.

7. The aerosol generating device according to claim 1, wherein while the control electronic device indicates the progress of the operation stage of the aerosol generating device to the user, each of the plurality of light emitting units is configured to be independently controlled such that it is initially in the first lighting state, then in the second lighting state after the first lighting state, and then in the off state after the second lighting state.

8. The aerosol generating device according to claim 1, wherein in response to detecting the progress of the operation stage of the aerosol generating device, the control electronic device is configured to change the state of only one of the plurality of light emitting units of the lighting array at a time.

9. The aerosol generating device according to claim 8, wherein the control electronic device is configured to detect the progress of the operation stage of the aerosol generating device by detecting one or more of user input, smoking on the device, generation of a predetermined amount of aerosol, or the time elapsed after user input or smoking on the device.

10. The aerosol generating device according to claim 1, wherein the plurality of light emitting units are in the off state during the (n + 5)-th stage of the operation of the aerosol generating device.

11. The aerosol generating device according to claim 1, further comprising one or more waveguides configured to direct the light generated by the plurality of light emitting units towards one or more display windows of the lighting array.

12. The aerosol generating device according to claim 1, wherein each of the plurality of light emitting units includes a light emitting diode, the control electronic device includes a light emitting diode control driver and a separate microcontroller, and the control driver is configured to control the supply of electricity from a power source to one or more of the plurality of light emitting diodes under the control of the microcontroller so that each of the light emitting units becomes one of the off state or one of the lighting states.

13. The aerosol generating device according to claim 12, wherein the light emitting diode control driver is configured to control the supply of electricity from a power source to one or more of the plurality of light emitting diodes by means of a pulse width modulation type having a predetermined resolution in order to control the luminance of the one or more of the plurality of light emitting diodes in each of the lighting states.

14. The control electronic device is configured to independently control each of the light emitting units in the off state, the first illumination state, and the second illumination state such that the light emitted by the light emitting unit in the first and second illumination states is one or more of use session light emission, low energy light emission, heat profile light emission, pause light emission, state change light emission, progress light emission, and preheat light emission. The aerosol generating device according to any one of claims 1 to 13.

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