Aerosol generating device and system comprising a residue detector

Abstract

The aerosol generating device (100) comprises a cavity (104) for receiving an aerosol-generating article including an aerosol-forming substrate, a heater (106) arranged to heat the aerosol-forming substrate received in the cavity (104), a power source (108), residue detection means, and a controller (110). The residue detection means is adapted to detect residue of the aerosol-forming substrate in the cavity (104) or on the heater (106). The controller (110) is configured to control the supply of power from the power source (108) to the heater (106) for heating the aerosol-forming substrate received in the cavity (104), receive a signal from the residue detection means indicative of the amount of aerosol-forming substrate residue in the cavity (104) or on the heater (106), and determine an indication of the amount of aerosol-forming substrate residue in the cavity (104) or on the heater (106) based on the one or more signals received from the residue detector.

Description

Technical Field

[0001] The present invention relates to an aerosol generation system and an aerosol generator having means for detecting the accumulation of residues of an aerosol-forming substrate on the aerosol generator.

Background Art

[0002] Aerosol generation systems in which an aerosol-forming substrate, such as a tobacco-containing substrate, is heated rather than burned are known in the art. The purpose of such aerosol generation systems is to reduce the known harmful smoke components produced by the combustion and pyrolysis of tobacco in conventional cigarettes. Typically, in such aerosol generation systems, the aerosol is generated by heat transfer from a heater of the aerosol generator to an aerosol-forming substrate or material in an aerosol-generating article physically separated from the aerosol generator. The aerosol-generating article may be located within, around, or downstream of the heater. During use, volatile compounds are released from the aerosol-forming substrate by heat transfer from the heater to the aerosol-forming substrate and entrained in the air drawn through the aerosol-generating article. The released compounds condense as they cool to form an aerosol, which can be inhaled by the consumer.

[0003] Generally, an aerosol-generating article for use in combination with an aerosol generator often comprises an aerosol-forming substrate assembled in the form of a rod, together with other elements or components. Generally, such rods are configured in a shape and size to be inserted into the cavity of an aerosol generator comprising a heater for heating the aerosol-forming substrate. In particular, an aerosol generation system that allows the aerosol-generating article to be replaced without the need to remove and replace the heater of the aerosol generator is desirable in order to reduce the cost and complexity of manufacturing the aerosol-generating article.

[0004] In some aerosol generation systems, the aerosol generating device comprises a heater having one or more heating elements disposed to surround an aerosol generating article inserted into a cavity of the device. In some aerosol generation systems, the aerosol generating device comprises a heater having one or more heating elements disposed to penetrate an aerosol generating article inserted into a cavity of the device and provide direct contact between the one or more heating elements and an aerosol forming substrate within the article. Direct contact between the heating element and the aerosol forming substrate may be desirable because the heating element provides efficient heating of the aerosol forming substrate and enables heat from the heating element to be transferred almost instantaneously by conduction to at least a portion of the aerosol forming substrate, facilitating rapid aerosol generation.

[0005] The interaction between the aerosol generating device in use and the aerosol generating article may result in deposits or residues from the aerosol forming substrate remaining on the walls of the cavity of the device and on the heater of the device after the article is removed from the cavity. Such deposits or residues can adversely affect the operation of the aerosol generation system and the generation of the aerosol.

[0006] It is desirable to provide an aerosol generation system that reduces the accumulation of residues of the aerosol forming substrate on the aerosol generating device. It is desirable to provide an aerosol generation system that promotes efficient heat transfer between the heater and the aerosol forming substrate. It is desirable to provide an aerosol generation system that promotes the generation of an aerosol having consistent characteristics. SUMMARY OF THE INVENTION

[0007] According to a first aspect of the present invention, there is provided an aerosol generating device comprising a cavity for receiving an aerosol generating article comprising an aerosol forming substrate, a heater disposed to heat the aerosol forming substrate received within the cavity, a power source, residue detection means, and a controller. The residue detection means is suitable for detecting residues of the aerosol forming substrate within the cavity or on the heater. The controller controls the supply of power from the power source to the heater for heating the aerosol forming substrate received within the cavity, receives a signal from the residue detection means indicative of the amount of residue of the aerosol forming substrate within the cavity or on the heater, and is configured to determine a display of the amount of residue of the aerosol forming substrate within the cavity or on the heater based on one or more signals received from the residue detector.

[0008] The inventors of the present invention have recognized that the accumulation of residues of the aerosol forming substrate on and around the heater of the aerosol generating device can adversely affect the operation of the aerosol generating device. For example, the accumulation of residues on the heater of the device can increase the time required for the heater to reach the desired temperature. The inventors of the present invention have also recognized that the accumulation of residues of the aerosol forming substrate on and around the heater of the aerosol generating device can adversely affect the aerosol generated by the device. For example, heating of the residues of the aerosol forming substrate over several uses of the system can result in the release of undesirable volatile compounds from the residues, which can change the flavor of the aerosol generated by the system.

[0009] Advantageously, the aerosol generating device according to the first aspect of the present invention comprises means for detecting residues of the aerosol-forming substrate remaining in the cavity or on the heater after the aerosol-generating article has been removed from the cavity, and a controller configured to receive a signal from the residue detection means and determine a display of the amount of residues of the aerosol-forming substrate remaining in the cavity or on the heater. Based on the determination of the display of the amount of residues of the aerosol-forming substrate remaining in the cavity or on the heater, it is possible to warn the user of an unacceptable accumulation of residues of the aerosol-forming substrate, take measures to prevent further use of the device until the residues are removed, and / or implement measures to remove the residues.

[0010] As used herein, the term "aerosol generating device" refers to a device that interacts with an aerosol-forming substrate to generate an aerosol. The aerosol-forming substrate may be part of the aerosol-generating article. As used herein, the aerosol generating device is an electrically heated aerosol generating device comprising a heater, a power supply, and a controller configured to control the supply of energy from the power supply to the heater to heat the aerosol-forming substrate to generate an aerosol.

[0011] As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate capable of releasing a volatile compound capable of forming an aerosol. For example, the aerosol-generating article may be an article that generates an aerosol that can be directly inhaled into the user's lungs through the user's mouth. The aerosol-generating article may be disposable. The aerosol-generating article is preferably a heated aerosol-generating article that comprises an aerosol-forming substrate intended to be heated rather than burned to release a volatile compound capable of forming an aerosol. The aerosol-generating article may be or may include a tobacco stick.

[0012] As used herein, the term "aerosol-forming substrate" relates to a substrate having the ability to release volatile compounds capable of forming an aerosol. Such volatile compounds may be released by heating the aerosol-forming substrate. The aerosol formed by heating the aerosol-forming substrate may contain fewer known harmful components than those produced by combustion or pyrolysis of the aerosol-forming substrate.

[0013] The aerosol-forming substrate may contain nicotine. The aerosol-forming substrate may contain both a solid component and a liquid component. The aerosol-forming substrate is preferably a solid aerosol-forming substrate. The aerosol-forming substrate may include tobacco, or a tobacco-containing material containing volatile tobacco flavor compounds released from the substrate upon heating. In a preferred embodiment, the aerosol-forming substrate includes a homogenized tobacco material, such as cast leaf tobacco.

[0014] The aerosol-forming substrate may contain non-tobacco materials. The aerosol-generating substrate may comprise a tobacco-containing material and a non-tobacco-containing material. The aerosol-forming substrate may include an aerosol-forming agent. Examples of suitable aerosol-forming agents are glycerin and propylene glycol.

[0015] When the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol-forming substrate contains one or more of herb leaves, tobacco leaves, fragments of tobacco stems, reconstituted tobacco, processed tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco, and may include, for example, one or more of powders, granules, pellets, fragments, spaghetti, shreds, or sheets. The solid aerosol-forming substrate may be in a loose form or may be provided in a suitable container or cartridge. For example, the aerosol-forming material of the substrate may be contained within paper or a wrapper and may have the form of a plug. When the aerosol-forming substrate is in the form of a plug, the entire plug, including any wrapping paper, is considered to be the aerosol-forming substrate.

[0016] In a preferred embodiment, the aerosol-forming substrate is contained within a rod-shaped article having a form similar to an aerosol-generating article, such as a cigarette. The aerosol-generating article is preferably of a suitable size and shape to engage with an aerosol-generating device such that the aerosol-forming substrate is brought into contact with a heating element of the device. For example, the aerosol-generating article may have an overall length of from approximately 30 mm to approximately 100 mm. The aerosol-generating article may have an outer diameter of from approximately 5 mm to approximately 12 mm. The terms upstream and downstream may be used to describe the relative positions of elements or components of a smoking article. Put simply, the terms upstream and downstream as used herein refer to the relative positions along the rod of the smoking article with respect to the direction in which aerosol is drawn through the rod.

[0017] As used herein, the term "residue of the aerosol-forming substrate" means an organic material that adheres or deposits within the cavity or on the heater. Typically, the residue of the aerosol-forming substrate includes the aerosol-forming substrate that may release volatile compounds whether heated or unheated by the heater of the device. The residue of the aerosol-forming substrate may deposit within the cavity or on the heater at any stage of using the aerosol-generating device in combination with an aerosol-generating article containing the aerosol-forming substrate (e.g., when the article is inserted into the cavity, when the article is heated by the heater to release volatile compounds from the aerosol-forming substrate, and when the article is removed from the cavity).

[0018] In particular, the residue of the aerosol-forming substrate refers to the residue remaining within the cavity or on the heater after the aerosol-generating article has been removed from the cavity.

[0019] References herein to residues of the aerosol-forming substrate remaining "within the cavity or on the heater" include residues within the cavity of the device, on the heater of the device, and residues on both within the cavity and on the heater of the device.

[0020] As used herein, the term "residue detection means" refers to any device, instrument, or configuration of an aerosol generating device for detecting residues of an aerosol-forming substrate within a cavity or on a heater. The residue detection means includes both a specific residue detector and a sensor provided within the aerosol generating device for detecting residues of the aerosol-forming substrate within the cavity or on the heater, and the aerosol generating device has a heater and a controller having a specific configuration for detecting residues of the aerosol-forming substrate on the heater. The residue detection means is preferably configured to detect residues of the aerosol-forming substrate remaining within the cavity or on the heater after an aerosol-generating article containing the aerosol-forming substrate has been removed from the cavity.

[0021] As used herein, the determination of the "indication" of the amount of residues of the aerosol-forming substrate within the cavity or on the heater refers to both the determination of the absolute value (such as the volume or thickness of the residue) of the amount of residue within the cavity or on the heater and the determination of the relative value (such as comparison with a predetermined threshold).

[0022] In some preferred embodiments, the controller is further configured to compare the indication of the determined amount of residues of the aerosol-forming substrate with a threshold value. The threshold value may be a predetermined threshold value. The predetermined threshold value may be stored in the memory of the controller. The threshold value may be predetermined in a calibration procedure before the aerosol generating device is used to generate aerosol.

[0023] The threshold value may correspond to the maximum allowable amount of residues of the aerosol-forming substrate within the cavity or on the heater. Thus, if the indication of the determined amount of residues of the aerosol-forming substrate exceeds the threshold value, it may be determined that the amount of residues of the aerosol-forming substrate within the cavity or on the heater exceeds an acceptable amount.

[0024] The controller may be further configured to prevent power from being supplied from the power source to the heater to heat the aerosol-forming substrate in the cavity when the determined indication exceeds a threshold. Advantageously, terminating the supply of power to the heater for heating the aerosol-forming substrate when the amount of residue of the aerosol-forming substrate in the cavity or on the heater exceeds an acceptable level may inhibit or prevent the generation of aerosol by the aerosol-generating device. This can ensure that the aerosol generated by the aerosol-generating device does not contain an unacceptable amount of volatile compounds released when heating the residue of the aerosol-forming substrate in the cavity or on the heater.

[0025] The controller may also be configured to continue to prevent power from being supplied from the power source to the heater to heat the aerosol-forming substrate in the cavity until a subsequent determined indication falls below the threshold.

[0026] In some embodiments, the controller may be further configured to supply power to the heater to raise the temperature of the heater to a first temperature to sufficiently heat the aerosol-forming substrate received in the cavity to form an aerosol, and to supply power to the heater to raise the temperature of the heater to a second temperature higher than the first temperature to thermally liberate organic material adhered or deposited in the cavity or on the heater.

[0027] The controller may be configured to raise the temperature of the heater to the second temperature when the determined indication exceeds a threshold.

[0028] The first temperature is desirably a temperature sufficient to cause the release of volatile compounds from the aerosol-forming substrate and thus the formation of an aerosol. The first temperature preferably remains below the temperature at which the aerosol-forming substrate burns.

[0029] The first temperature is preferably lower than about 375 degrees Celsius. For example, the first temperature can be from 80 degrees Celsius to 375 degrees Celsius, such as from 100 degrees Celsius to 350 degrees Celsius. The length of time the heater is maintained at the first temperature may be fixed. For example, the first temperature may be maintained for a period longer than 2 seconds, such as between 2 seconds and 10 seconds. The length of time the heater is maintained at the first temperature may also be variable. For example, the aerosol generating device may be equipped with a sensor that determines when the user is inhaling an article, and this time can be controlled according to the length of time the user inhales the article.

[0030] The second temperature is preferably high enough to thermally liberate the organic compound in contact with the heater. In other words, the second temperature is high enough to liberate the residue of the aerosol-forming substrate from the heater. Thermal liberation of the organic compound can occur by pyrolysis. Pyrolysis is the process by which a chemical compound decomposes under the action of heat. Organic compounds generally pyrolyze to form organic vapors and liquids, which in this specification can move away from the heater and keep the heater in a clean state. Therefore, the process of raising the temperature of the heater to the second temperature to liberate the aerosol-forming substrate from the heater and the cavity can be referred to in this specification as a cleaning cycle or a pyrolysis cycle.

[0031] The organic material deposited on the heater is preferably thermally liberated by raising the temperature of the heater to about 430 degrees Celsius or higher. For example, the temperature can be raised to 475 degrees Celsius or higher, or to 550 degrees Celsius or higher. The temperature can be raised to even higher temperatures, such as 600 degrees Celsius or higher, or 800 degrees Celsius or higher.

[0032] The heater is desirably maintained at the second temperature for a certain period of time to effect thermal liberation of the organic compound. For example, the heater may be maintained at the second temperature for more than 5 seconds. The heater is preferably maintained at the second temperature for between about 5 seconds and about 60 seconds, such as between about 10 seconds and about 30 seconds.

[0033] The heater can be any suitable type of heater.

[0034] In some embodiments, the heater is arranged to heat the outer surface of the aerosol-forming substrate. In some preferred embodiments, the heater is arranged to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity. The heater may be positioned within the cavity. The heater may extend into the cavity. The heater may be an elongate heater. The elongate heater may be in the shape of a blade. The elongate heater may be in the shape of a pin. The elongate heater may be in the shape of a cone. In some particularly preferred embodiments, the aerosol-generating device comprises an elongate heater arranged to be inserted into the aerosol-generating article when the aerosol-generating article is received within the cavity.

[0035] The heater may comprise at least one heating element. The at least one heating element can be any suitable type of heating element. In some embodiments, the device comprises only one heating element. In some embodiments, the device comprises a plurality of heating elements.

[0036] The heater may include at least one resistive heating element. Preferably, the heater includes a plurality of resistive heating elements. The resistive heating elements are preferably electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement can facilitate the delivery of the desired power to the heater while reducing or minimizing the voltage required to provide the desired power. Advantageously, reducing or minimizing the voltage required to operate the heater can facilitate reducing or minimizing the physical size of the power source.

[0037] Suitable materials for forming at least one resistive heating element include, but are not limited to, semiconductors such as doped ceramics, "conductive" ceramics (e.g., molybdenum disilicide, etc.), carbon, graphite, metals, metal alloys, and composite materials made of ceramic materials and metal materials. Such composite materials may include doped ceramics or undoped ceramics. An example of a suitable doped ceramic is doped silicon carbide. Examples of suitable metals include titanium, zirconium, tantalum, and platinum group metals. Examples of suitable metal alloys include stainless steel, nickel-containing, cobalt-containing, chromium-containing, aluminum-containing, titanium-containing, zirconium-containing, hafnium-containing, niobium-containing, molybdenum-containing, tantalum-containing, tungsten-containing, tin-containing, gallium-containing, manganese-containing, and iron-containing alloys, as well as nickel, iron, cobalt, stainless steel-based superalloys, Timetal (registered trademark), and iron-manganese-aluminum-based alloys.

[0038] In some embodiments, at least one resistive heating element includes one or more stamped portions of an electrically resistive material (such as stainless steel). Alternatively, at least one resistive heating element may include a heating wire or filament (e.g., a Ni-Cr (nickel-chromium), platinum, tungsten, or alloy wire).

[0039] In some embodiments, at least one heating element includes an electrically insulated substrate, and at least one resistive heating element is provided on the electrically insulated substrate.

[0040] The electrically insulated substrate can comprise any suitable material. For example, the electrically insulated substrate can comprise one or more of paper, glass, ceramic, anodized metal, coated metal, and polyimide. The ceramic can comprise mica, alumina (Al2O3) or zirconia (ZrO2). The electrically insulated substrate preferably has a thermal conductivity of about 40 watts per meter kelvin or less, preferably about 20 watts per meter kelvin or less, and ideally about 2 watts per meter kelvin or less.

[0041] The heater preferably comprises a heating element including a rigid electrically insulated substrate having one or more conductive tracks or wires disposed on its surface. Depending on the size and shape of the electrically insulated substrate, it is preferably possible to insert it directly into the aerosol-forming substrate. If the electrically insulated substrate is not sufficiently rigid, the heating element may include further reinforcing means. The current can pass through one or more conductive tracks to heat the heating element and the aerosol-forming substrate.

[0042] In some embodiments, the heater comprises an induction heating arrangement. The induction heating arrangement can include an inductor coil and a power source configured to provide a high-frequency oscillating current to the inductor coil. As used herein, the high-frequency oscillating current means an oscillating current having a frequency of 500 kHz to 30 MHz. The heater can advantageously include a DC / AC inverter for converting a DC current supplied by a DC power source into an AC current. The inductor coil can be arranged to generate a high-frequency oscillating electromagnetic field when receiving a high-frequency oscillating current from the power source. The inductor coil may be arranged to generate a high-frequency oscillating electromagnetic field within the device cavity. In some preferred embodiments, the inductor coil may substantially surround the device cavity. The inductor coil can extend at least partially along the length of the device cavity.

[0043] The heater may include an induction heating element. The induction heating element may be a susceptor element. As used herein, the term "susceptor element" refers to an element that includes a material having the ability to convert electromagnetic energy into heat. When the susceptor element is located within an alternating electromagnetic field, the susceptor is heated. The heating of the susceptor element can be the result of at least one of the hysteresis losses and eddy currents induced within the susceptor, depending on the electrical and magnetic properties of the susceptor material.

[0044] The susceptor element may be arranged such that when the aerosol-generating article is received within the cavity of the aerosol-generating device, an oscillating electromagnetic field generated by an inductor coil induces a current within the susceptor element and heats the susceptor element. In these embodiments, it is preferred that the aerosol-generating device has the ability to generate a varying electromagnetic field having a magnetic field strength (intensity of the H-field) of 1 to 5 kiloamperes per meter (kA / m), preferably 2 to 3 kA / m, for example about 2.5 kA / m. An electrically operating aerosol-generating device preferably has the ability to generate a varying electromagnetic field having a frequency of 1 to 30 MHz, for example 1 to 10 MHz, for example 5 to 7 MHz.

[0045] In some embodiments, the susceptor element is located within the aerosol-generating article. In these embodiments, the susceptor element is preferably located in contact with the aerosol-forming substrate. The susceptor element may be located within the aerosol-forming substrate.

[0046] In some embodiments, the susceptor element is located within the aerosol-generating device. In these embodiments, the susceptor element may be located within the cavity. The aerosol-generating device may include only one susceptor element. The aerosol-generating device may comprise a plurality of susceptor elements.

[0047] In some embodiments, the susceptor element is arranged to heat the outer surface of the aerosol-forming substrate. In some embodiments, the susceptor element is arranged to be inserted into the aerosol-forming substrate when the aerosol-forming substrate is received within the cavity.

[0048] The susceptor element may comprise any suitable material. The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-forming substrate. Materials suitable for an elongate susceptor element include graphite, molybdenum, silicon carbide, stainless steel, niobium, aluminum, nickel, nickel-containing compounds, titanium, and composites of metallic materials. Preferred susceptor elements include metal or carbon. Advantageously, the susceptor element may comprise or consist of a ferromagnetic alloy such as, for example, ferromagnetic iron, ferromagnetic steel or stainless steel, ferromagnetic particles, and ferromagnetic materials such as ferrite. A suitable susceptor element may be or may include aluminum. The susceptor element preferably contains more than 5 percent of a ferromagnetic or paramagnetic material, more preferably more than 20 percent of a ferromagnetic or paramagnetic material, and even more preferably more than 50 percent or more than 90 percent of a ferromagnetic or paramagnetic material. Preferred elongate susceptor elements can be heated to temperatures in excess of 250 degrees Celsius.

[0049] The susceptor element may include a non-metallic core having a metal layer disposed thereon. For example, the susceptor element may include metal tracks formed on the outer surface of a ceramic core or substrate.

[0050] In some embodiments, the aerosol generating system comprises at least one resistive heater and at least one inductive heater. In some embodiments, the aerosol generating system comprises a combination of a resistive heater and an inductive heater.

[0051] The residue detection means may comprise any suitable configuration of an aerosol generating device, a sensor, or a combination of sensors for detecting residues of the aerosol-forming substrate within the cavity, on the heater, or both within the cavity and on the heater.

[0052] In some preferred embodiments, the heater includes a resistive heating element, and the residue detector means includes the configuration of a controller. As a result, the controller is configured to measure the resistance of the heating element and determine an indication of the amount of residue of the aerosol-forming substrate on the heating element based on the measured resistance of the heating element. In these preferred embodiments, the residue detection means is specifically configured to detect the residue of the aerosol-forming substrate remaining on the heater after the aerosol-generating article has been removed from the cavity.

[0053] Advantageously, configuring the controller to measure the resistance of the resistive heating element of the heater and determine an indication of the amount of residue of the aerosol-forming substrate on the heater based on the measured resistance minimizes the number of component parts of the aerosol-generating device.

[0054] In some particularly preferred embodiments, there is provided an aerosol-generating device comprising a housing defining a cavity for receiving an aerosol-generating article comprising an aerosol-forming substrate, and an elongate heater arranged to be inserted into the aerosol-generating article when the aerosol-generating article is received within the cavity, the heater including a resistive heating element, a power source, and a controller. In these particularly preferred embodiments, the controller may be configured to control the supply of power from the power source to the heater, measure the resistance of the resistive heating element, and determine an indication of the amount of residue of the aerosol-forming substrate on the heater based on the measured resistance of the resistive heating element.

[0055] In some embodiments, the determination of the indication of the amount of residue of the aerosol-forming substrate in the cavity is based on the rate of change of the measured resistance of the resistive heating element. The presence of residue of the aerosol-forming substrate on the heater can increase the length of time it takes to raise the temperature of the heater from a first temperature to a second temperature when a given power is supplied to the heater. Since the resistance of the heater depends on the temperature of the heater, the rate of change of the temperature of the heater can be related to the rate of change of the resistance of the heater. As a result, the presence of residue of the aerosol-forming substrate on the heater can reduce the rate of change of the resistance of the heating element with respect to the given power supplied to the heater. Advantageously, measuring the rate of change of the resistance of the heater can provide an indication of the amount of residue of the aerosol-forming substrate on the heater without the need to provide additional sensors within the aerosol-generating device.

[0056] The controller may be configured to determine an indication of the amount of residue of the aerosol-forming substrate in the cavity based on the resistance measurement taken after the aerosol-generating article has been removed from the cavity. Advantageously, this ensures that the residue detection means detects the residue of the aerosol-forming substrate in the cavity or on the heater rather than detecting the aerosol-forming substrate in the aerosol-generating article received within the cavity.

[0057] In some preferred embodiments, the controller is configured to determine an indication of the amount of residue of the aerosol-forming substrate in the cavity based on the resistance measurement taken at least a predetermined period after the end of the supply of power from the power source to the heater for heating the aerosol-forming substrate in the cavity. Advantageously, waiting for a predetermined period after the heater has been heated before making the residue determination can provide the controller with a reasonably reliable indication that the aerosol-generating article has been removed from the cavity without the need to include additional sensors within the device.

[0058] In some preferred embodiments, the controller is configured to supply power from a power source to the heater to heat the aerosol-forming substrate received within the cavity, terminate the supply of power to the heater for heating the aerosol-forming substrate received within the cavity, and after a predetermined time, measure the resistance of the resistive heating element of the heater and determine a display of the amount of residue of the aerosol-forming substrate on the heater based on the measured resistance value of the resistive heating element.

[0059] In some embodiments, the controller is configured to determine smoking characteristics of a user's aerosol-generating device from measured values of the resistance of one or more heating elements of the heater. The controller may be further configured to determine a display of the amount of residue of the aerosol-forming substrate within the cavity or on the heater based on the determined smoking characteristics of the user. The determination of the display of the amount of residue of the aerosol-forming substrate within the cavity or on the heater may be based on changes in the time-dependent characteristics of the determined smoking of the user.

[0060] The performance of an aerosol-generating device, particularly the resistive heater of an aerosol-generating device, can change as a result of residue within the cavity or on the heater. The inventors of the present invention have recognized that such changes in the performance of an aerosol-generating device can lead to changes in the use of the aerosol-generating device by the user. For example, a user may be able to inhale more forcefully on an aerosol-generating device having a residue of an aerosol-forming substrate within the cavity or on the heater than on a device having no residue within the cavity or on the heater. This change in use can be due, for example, to a change in the draw resistance of the aerosol-generating device or a reduction in the volume of aerosol generated by the device.

[0061] The determined smoking characteristics of the user may be any suitable characteristics. For example, the determined smoking characteristics of the user may be one or more of the volume of smoking and the duration of smoking.

[0062] The smoking characteristics of the user's device can be reflected in the resistance as the temperature of the resistive heating element of the heater. The airflow through the aerosol generating device caused by the user's smoking can lower the temperature of the heater. The temperature fluctuations of the heater caused by the user's smoking of the device are time-dependent and distinguishable from other fluctuations in the heater temperature. Further, the change in the temperature fluctuations of the heater caused by the user's smoking of the device may be determined over time. The controller may be configured to monitor the change in the temperature fluctuations of the heater caused by the user's smoking of the device over time and, based on the detected change, determine an indication of the amount of residue of the aerosol-forming substrate in the cavity or on the heater.

[0063] The residue detection means may include one or more residue detectors. The residue detector includes any detector or sensor suitable for detecting residues in the cavity or on the heater. In particular, suitable residue detectors include volatile organic compound (VOC) detectors, carbon dioxide detectors, optical detectors, acoustic detectors, and capacitance detectors. The one or more residue detectors may be electromechanical devices. The one or more residue detectors may be any of a mechanical device, an optical device, an opto-mechanical device, and a microelectromechanical system (MEMS)-based sensor. The one or more residue detectors are preferably MEMS-based sensors. The one or more residue detectors may be disposed in or around the cavity. The one or more residue detectors may be disposed in the cavity. The one or more residue detectors may be disposed on the surface of the cavity. The one or more residue detectors may be disposed on the heater.

[0064] In some embodiments, the residue detection means includes a volatile organic compound detector. The residue detection means may include one or more sensors for detecting volatile organic compounds (VOCs). As used herein, the term "organic compound" means any compound containing at least elemental carbon, and one or more of hydrogen, halogen, oxygen, sulfur, phosphorus, silicon, or nitrogen, excluding carbon oxides and inorganic carbonates and bicarbonates. As used herein, the term "volatile organic compound (VOC)" means any organic compound having a vapor pressure of 0.01 kilopascals (kPa) or more at 293.15 Kelvin (K), or having a corresponding volatility under specific use conditions. The definitions of "organic compound" and "volatile organic compound" used herein are derived from the Directive 2010 / 75 / EU of the European Parliament and of the Council of 24 November 2010 (Integrated Pollution Prevention and Control) regarding industrial emissions.

[0065] The one or more volatile organic compound sensors can be of any suitable type. For example, suitable VOC sensors include electrochemical gas sensors such as chemicfield effect transistors, chemiresistive sensors, metal oxide semiconductor (MOS) sensors, catalytic sensors (peristats), microcantilever array sensors, surface acoustic wave (SAW) sensors, photoionization detectors (PIDs), and infrared sensors.

[0066] Some exemplary suitable VOC sensors currently available include the SGP30 and SGPC3 from Sensirion AG, the TGS2602 from FIGARO USA., INC, and the MiCS-VZ-89TE from SGX Sensortech Limited.

[0067] In some embodiments, the residue detection means includes a gas sensor for detecting the presence of one or more gases in the cavity. The one or more gas sensors are preferably configured to detect carbon dioxide.

[0068] The inventors of the present invention recognized that the residue of the aerosol-forming substrate can release a specific gas. The gas released by the residue of the aerosol-forming substrate is detected by a gas detector and can be used to provide an indication of the amount of residue of the aerosol-forming substrate present within the cavity or on the heater.

[0069] The one or more gas sensors can be of any suitable type. Suitable types of gas sensors include electrochemical gas sensors such as chemifield effect transistors, chemiresistive sensors, metal oxide semiconductor (MOS) sensors, catalytic sensors (peristats), microcantilever array sensors, surface acoustic wave (SAW) sensors, photoionization detectors (PIDs), and infrared sensors.

[0070] Some exemplary suitable gas sensors currently available include the SGP30 and SGPC3 from Sensirion AG, the CDM7160-C00 and TGS2602 from FIGARO USA., INC, and the MiCS-VZ-89TE from SGX Sensortech Limited.

[0071] In some embodiments, the residue detection means includes an optical detector. The optical detector may include a light source. The light source may be arranged to direct light into the cavity. The optical detector may include a light sensor. The light sensor may be arranged to receive light from the cavity.

[0072] Preferably, the optical detector includes a light source and a light sensor. The optical detector may further include one or more optical guides. The one or more optical guides may be arranged to direct light from the light source into the cavity. The one or more optical guides may be arranged to direct light from the cavity to the light sensor.

[0073] The light source may be any suitable light source. Typically, the light source may include a light emitting diode (LED). The light source is preferably configured to emit white light. In other words, the light source is preferably configured to emit a broad wavelength band. For example, if the light source includes an LED, the light source may further include a phosphor configured to absorb the light from the LED and fluorescent light of different complementary wavelengths. The light source may include a plurality of LEDs configured to emit different wavelengths.

[0074] The light sensor may be any suitable light sensor. Typically, the light sensor is a light detector such as a photodiode. For example, the light sensor may include a PN photodiode, a PIN photodiode, or an avalanche photodiode. The light sensor may include a phototransistor.

[0075] In embodiments including an optical detector, the surface defining the cavity is preferably configured to reflect the wavelength of the light emitted by the light source. For example, the surface of the cavity may be white. The surface defining the cavity may be coated with a reflective coating such as a white coating, or may be coated in other ways. The material forming the surface of the cavity may be white.

[0076] The inventors of the present invention have recognized that spectroscopy can be used to detect the presence of residues in the cavity. In particular, the inventors have recognized that diffuse absorption spectroscopy can be used to provide an indication of the amount of residue of the aerosol-forming substrate present in the cavity. A photodiode can be used to measure the intensity of the light in the cavity, which can provide an indication of the amount of residue in the cavity. The residue of the aerosol-forming substrate may have specific optical indicators that can be monitored by a controller.

[0077] In some embodiments, the optical sensor includes an optical waveguide. The optical waveguide can be disposed at any suitable position within the aerosol generator. In some embodiments, the heater may include an optical waveguide. For example, the optical waveguide may be fixed to the mount of the heater. In some embodiments, the aerosol generator includes a extractor for removing the aerosol generating article from the cavity, and the extractor may include one or more optical waveguides. In these embodiments, the one or more optical waveguides may be arranged to be aligned with the one or more light sources and optical sensors when the extractor is disposed at a predetermined position on the aerosol generator.

[0078] In some embodiments, the residue detection means includes an acoustic detector.

[0079] The cavity may have a specific acoustic resonance frequency. Residues of the aerosol-forming substrate within the cavity can change the mass and shape of the cavity, thereby changing the resonance frequency of the cavity. The heater may have a specific acoustic resonance frequency. Residues of the aerosol-forming substrate on the heater can change the mass and shape of the heater, thereby changing the resonance frequency of the heater.

[0080] The inventors of the present invention have recognized that an acoustic detector can be used to detect changes in the acoustic resonance frequency in one or more of the cavity and the heater. A change in the acoustic resonance frequency of the cavity can provide an indication of the amount of residue of the aerosol-forming substrate within the cavity. A change in the resonance frequency of the heater can provide an indication of the amount of residue of the aerosol-forming substrate on the heater.

[0081] The acoustic detector can be configured to generate vibrations (i.e., mechanical waves or sound waves). The frequency of the generated vibrations may be variable. The acoustic detector may include an output transducer. The output transducer can convert an electrical signal into vibrations. In particular, the output transducer may be a loudspeaker. Typically, a loudspeaker is an electroacoustic transducer. The oscillator is preferably a crystal loudspeaker such as a piezoelectric speaker.

[0082] The acoustic detector may be configured to receive mechanical waves. The acoustic detector may include an input transducer. The input transducer may convert vibrations into an electrical signal. The input transducer may be a piezoelectric transducer.

[0083] The acoustic detector is preferably a piezoelectric acoustic wave sensor.

[0084] The acoustic detector may be disposed on the surface of the cavity. The acoustic detector is preferably disposed on the heater. The heater is an elongated heater configured to be inserted into the aerosol forming substrate, and the acoustic detector is preferably disposed on the heater.

[0085] In some embodiments, the residue detection means includes a capacitance sensor. The inventors of the present invention have recognized that the residue of the aerosol forming substrate may have dielectric properties, which can be detected by the capacitance sensor.

[0086] The capacitance sensor is preferably disposed in or around the cavity. The capacitance sensor may extend over at least a portion of the base of the cavity. The capacitance sensor may extend over at least a portion of the side wall of the cavity.

[0087] The capacitance sensor may include at least two electrodes. The capacitance sensor preferably includes two interlocking electrodes. In embodiments comprising a capacitance sensor having two interlocking electrodes, each of the interlocking electrodes is electrically connected together by a main track and includes a plurality of protrusions with spaces therebetween to provide a space between adjacent protrusions. The protrusions and spaces of each electrode may be arranged in a regular or periodic arrangement. Typically, the two interlocking electrodes are arranged such that the protrusions of each electrode extend into the spaces between the protrusions of the other electrode.

[0088] The protrusions of each of the mutually engaged electrodes may be substantially the same. The spaces between the protrusions of each of the mutually engaged electrodes may be substantially the same. The width of the space between adjacent protrusions of the electrodes may be referred to as the spatial wavelength λ or the bandgap of the electrodes.

[0089] An example of a suitable pair of mutually engaged electrodes may be the DRP-G-IDEPT10 sensor manufactured by DropSens (trademark).

[0090] One of the pair of mutually engaged electrodes may be configured as a drive electrode. The drive electrode may be supplied with an oscillation voltage. The other electrode may be configured as a sensing electrode. The sensing electrode may detect the electric field generated by the drive electrode. The electric field generated by the drive electrode includes a fringe electric field caused by the fringing electric field at the ends of the fingers of the drive electrode. The fringe electric field includes a component extending from the surface where the mutually engaged electrodes are disposed substantially perpendicular to the surface. Therefore, the fringe electric field generated by the drive electrode extends into the material disposed above or adjacent to the electrodes.

[0091] The electrical properties of the material disposed above or adjacent to the pair of mutually engaged electrodes may affect the fringe electric field generated by the drive electrode. For example, the dielectric properties of the material disposed above or adjacent to the pair of mutually engaged electrodes may affect the generated fringe electric field. Therefore, the sensing electrode of the pair of mutually engaged electrodes may sense a change in the electrical properties of the material disposed above or adjacent to the pair of mutually engaged electrodes.

[0092] When the residue of the aerosol-forming substrate is disposed above or adjacent to the electrodes, the fringe electric field may extend into the residue of the aerosol-forming substrate.

[0093] In some embodiments, the residue detection means includes a smoking detector. The smoking detector can include any suitable sensor capable of determining the characteristics of smoking of the aerosol generating device. For example, the smoking detector can include an airflow sensor such as a pressure sensor. The smoking detector can be disposed in the airflow path of the device and configured to detect the characteristics of smoking of the user's aerosol generating device. The characteristics of the user's smoking can be the volume or duration of smoking. The controller can typically be configured to determine the change in the characteristics of smoking over time for a plurality of smokes, such as 10 or 20 smokes. The controller can be configured to determine whether the change in the characteristics of smoking over time provides an indication of the amount of residue of the aerosol-forming substrate in the cavity. The controller can be configured to determine whether the change in the characteristics of smoking over time provides an indication of the amount of residue of the aerosol-forming substrate on the heater.

[0094] In some embodiments, the controller is configured to determine an indication of the amount of residue based on measurements from the residue detection means when the aerosol-forming substrate is received in the cavity and power is supplied to the heater to heat the aerosol-forming substrate. In particular, in embodiments where the residue detection means determines an indication of the amount of residue based on the characteristics of smoking of the user's device, the controller is configured to determine an indication of the amount of residue based on measurements from the residue detection means when the aerosol-forming substrate is received in the cavity and power is supplied to the heater to heat the aerosol-forming substrate.

[0095] In other embodiments, it is preferred that the controller is configured to determine an indication of the amount of residue when the aerosol-forming substrate is not received in the cavity. In particular, in embodiments including one or more residue detectors, it is preferred that the controller is configured to determine an indication of the amount of residue when the aerosol-forming substrate is not received in the cavity.

[0096] In some embodiments, the aerosol generating device may include a button, switch, or another type of user input to initiate determination of residues within the cavity or on the heater. In these embodiments, the user is involved in determining when the aerosol forming substrate is not received within the cavity. When the user input is activated by the user, the controller is configured to determine a display of the amount of residue.

[0097] In some embodiments, the controller is configured to determine a display of the amount of residue based on a signal received from the residue detection means after the aerosol generating article has been removed from the cavity. In these embodiments, the controller is configured to determine that the aerosol generating article has been removed from the cavity. Advantageously, this ensures that the residue detection means detects residues of the aerosol forming substrate within the cavity or on the heater rather than the aerosol forming substrate within the aerosol generating article received within the cavity.

[0098] The controller may be configured to determine that the aerosol generating article has been removed from the cavity in any suitable manner.

[0099] In some preferred embodiments, the controller is configured to determine a display of the amount of residue of the aerosol forming substrate within the cavity based on a signal received from the residue detection means after the supply of power from the power source to the heater for heating the aerosol forming substrate within the cavity has ended. In some particularly preferred embodiments, the controller is configured to determine a display of the amount of residue of the aerosol forming substrate within the cavity based on a signal received from the residue detection means at least after a predetermined period after the supply of power from the power source to the heater for heating the aerosol forming substrate within the cavity has ended. Advantageously, waiting for a predetermined period after heating the heater before performing residue determination can provide the controller with a reasonably reliable indication that the aerosol generating article has been removed from the cavity without the need to include additional sensors within the device.

[0100] In some preferred embodiments, the aerosol generating device further comprises aerosol generating article detecting means configured to detect the presence of an aerosol generating article within the cavity. The aerosol generating article detecting means may include one or more suitable sensors. For example, the aerosol generating article detecting means may include one or more proximity sensors. The proximity sensor may be, for example, an optical sensor, a capacitance sensor, or an ultrasonic detector.

[0101] The controller may be configured to receive a signal from the aerosol generating article detecting means. The controller may be further configured to determine a display of the amount of residue of the aerosol forming substrate within the cavity based on the signal received from the residue detecting means when the signal from the aerosol generating article detecting means indicates that an aerosol generating article is received within the cavity.

[0102] The aerosol generating device comprises a controller. The controller may include a microprocessor, which may be a programmable microprocessor, a microcontroller, or an application specific integrated circuit chip (ASIC) or other electronic circuitry having the ability to provide control. The controller may further include additional electronic components. In some embodiments, the controller may include residue detecting means.

[0103] The aerosol generating device may be provided with a power source. The power source may be a DC power source. In a preferred embodiment, the power source is a battery. The power source may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery (such as a lithium cobalt, lithium iron phosphate, or lithium polymer battery). However, in some embodiments, the power source may be another form of charge storage device such as a capacitor. The power source may be required to be rechargeable and may have a capacity that allows for the accumulation of sufficient energy for one or more user operations, such as one or more experiences of aerosol generation. For example, the power source may have a capacity sufficient to enable continuous heating of the aerosol-forming substrate for about 6 minutes, or a multiple of 6 minutes, corresponding to the typical time taken to smoke one conventional cigarette. In another example, the power source may have a capacity sufficient to enable a predetermined number of smoking sessions or discontinuous activation of the heater.

[0104] The aerosol generating device preferably comprises a residue indicator for indicating to the user the amount of determined residue within the cavity or on the heater. The residue indicator may include a visual indicator such as a display or one or more lights. The residue indicator may include an audible indicator such as a loudspeaker or a buzzer. Typically, the residue indicator is connected to a controller. The controller may be configured to transmit a signal to the residue indicator to indicate to the user the amount of determined residue within the cavity or on the heater. In some embodiments, the controller is configured to transmit a signal to the residue indicator when the amount of determined residue within the cavity or on the heater exceeds a threshold. Advantageously, by providing one or more residue indicators in the aerosol generating device, the controller of the aerosol generating device may be able to warn the user when an unacceptable amount of residue of the aerosol-forming substrate is detected within the cavity or on the heater.

[0105] The aerosol generating device preferably comprises a housing. The housing preferably at least partially defines a cavity for receiving the aerosol forming substrate. The housing may have a proximal end and a distal end. The chamber may be disposed at the proximal end of the device.

[0106] The housing may be elongated. The housing is preferably cylindrical. The housing may comprise any suitable material or combination of materials. Examples of suitable materials include metals, alloys, plastics, or composite materials containing one or more of these materials, or thermoplastic resins suitable for food or pharmaceutical applications, such as polypropylene, polyetheretherketone (PEEK), and polyethylene. The material is preferably light and not brittle.

[0107] The aerosol generating device is preferably portable. The aerosol generating device may have a length of approximately 70 millimeters to approximately 120 millimeters. The aerosol generating device may be a hand-held device. In other words, the aerosol generating device may be sized and shaped to be held in a user's hand.

[0108] The aerosol generating device may comprise at least one air inlet in fluid communication with the cavity. In embodiments where the aerosol generating device comprises a housing, the housing preferably at least partially defines at least one air inlet. The at least one air inlet is preferably in fluid communication with the distal end of the cavity. In embodiments where the at least one heater is an elongated at least one heater positioned within the cavity, the elongated at least one heater preferably extends from the distal end of the cavity into the cavity.

[0109] The aerosol generating device preferably comprises a heater indicator for indicating when the at least one heater is activated. The heater indicator may include a light that is activated when the at least one heater is activated.

[0110] The aerosol generating device may comprise at least one of an external plug or socket that enables the aerosol generating device to be connected to another electrical device such as a charging device, and at least one external electrical contact. For example, the aerosol generating device may comprise a USB plug or socket that enables the aerosol generating device to be connected to another USB-enabled device. For example, the USB plug or socket may enable the connection of the aerosol generating device to a USB charging device in order to charge a rechargeable power source within the aerosol generating device. The USB plug or socket may support data transfer to or from the aerosol generating device, or both. Additionally, or alternatively, the aerosol generating device may be connected to a computer in order to transfer data such as a new heating profile for a new aerosol article to the device.

[0111] According to a second aspect of the present invention, there is provided an aerosol generating system comprising an aerosol generating device and a case for receiving the aerosol generating device. The aerosol generating device comprises a device cavity for receiving an aerosol article comprising an aerosol forming substrate, a heater disposed to heat the aerosol forming substrate received within the device cavity, a power source, and a device controller configured to control the supply of power from the power source to the heater for heating the aerosol forming substrate received within the device cavity. The case comprises a case cavity for receiving the aerosol generating device, a residue detector disposed to detect residues of the aerosol forming substrate within the device cavity or on the heater when the aerosol generating device is received within the case cavity, and a case controller. The case controller is configured to receive a signal from the residue detector indicative of the amount of residues of the aerosol forming substrate within the device cavity or on the heater, and to determine a display of the amount of residues of the aerosol forming substrate within the device cavity or on the heater based on the signal received from the residue detector.

[0112] According to a third aspect of the present invention, there is provided a case for receiving an aerosol generating device. The case includes a case cavity for receiving the aerosol generating device, a residue detector disposed to detect residues of the aerosol forming substrate within the device, and a case controller. The case controller is configured to receive, from the residue detector, a signal indicating the amount of residues of the aerosol forming substrate within the device, and to determine a display of the amount of residues of the aerosol forming substrate within the device based on the signal received from the residue detector.

[0113] Advantageously, by providing a case for receiving the aerosol generating device and providing a residue detector for the aerosol forming substrate in the case, the aerosol generating device can remain small and lightweight without having additional components of the residue detector, while also providing the system with the advantages of residue detection described above in relation to the first aspect of the present invention.

[0114] Advantageously, the size of the case is generally larger than the size of the aerosol generating device, which may enable a larger residue detector to be provided within the case rather than within the aerosol generating device.

[0115] In some particularly preferred embodiments, both the aerosol generating device and the charging unit may include residue detection means. The aerosol generating device may include first residue detection means, and the charging unit may include second residue detection means.

[0116] The features of the case described herein may be equally applicable to the case of the aerosol generating system according to the second aspect of the present invention and the case of the third aspect of the present invention.

[0117] The case includes a case cavity for receiving the aerosol generator. The case may be configured such that the aerosol generator can be received within the case cavity only when the aerosol article is not received within the aerosol generator. For example, the case cavity may be sized to receive the aerosol generator but not an aerosol generator containing an aerosol article received therein. Advantageously, in these embodiments, by providing the residue detector in the case rather than in the aerosol generator, it can be ensured that measurements from the residue detector are obtained only when the cavity of the aerosol generator does not contain an aerosol article.

[0118] The case preferably comprises a case housing. The case housing may at least partially define a case cavity for receiving the aerosol generator. The case housing may substantially surround or enclose the aerosol generator when the aerosol generator is received within the case cavity.

[0119] The case cavity may be an open cavity having at least one open end for receiving the aerosol generator. The case housing may include a plurality of parts. The case housing may include a first part and a second part. The second part may be movable relative to the first part. The second part may be rotatable or slidable relative to the first part. The second part may be removable from the first part. The first part and the second part may be movable between an open position and a closed position. In the open position, the case cavity may be opened to receive the aerosol generator. In the closed position, the case cavity may be closed to substantially surround or enclose the aerosol generator. The first part may be a body substantially defining the case cavity, and the second part may be a lid. The lid may be movable relative to the body to open and close the case cavity.

[0120] The case housing may be formed from any of the materials listed above for the aerosol generating device housing. The case housing may be formed from the same material as the device housing. The case is preferably portable. The case may be a hand-held case. In other words, the case may be sized and shaped to be held in the user's hand.

[0121] As described above in connection with the first aspect of the present invention, the residue detector of the case may be any suitable residue detector. In particular, suitable residue detectors include gas detectors such as volatile organic compound (VOC) detectors, carbon dioxide detectors, optical detectors, acoustic detectors, and capacitance detectors.

[0122] One or more residue detectors may be disposed at any suitable location within the case. One or more residue detectors may be disposed in the cavity of the aerosol generating device or in a location around the aerosol generating device when the aerosol generating device is received within the case cavity. If the case comprises a case housing having a first portion and a second portion movable relative to the first portion, the case controller may be disposed in the first portion and one or more residue detectors may be disposed in the second portion. If the case comprises a case housing having a body and a lid, one or more residue detectors may be disposed on the lid. In these embodiments, the case controller may be disposed within the body of the case housing. The case controller and one or more residue detectors disposed on the lid may be connected by a flexible circuit. Advantageously, by disposing one or more residue detectors on the lid of the case, when the aerosol generating device is received within the case cavity and the lid moves from an open position to a closed position, the one or more residue detectors can be moved close to or inside the device cavity of the aerosol generating device.

[0123] When the residue detector includes a VOC detector, a carbon dioxide detector, other gas detectors, or an optical detector, the detector may be disposed inside or outside the device cavity when the aerosol generator is received in the case cavity. When the residue detector includes an acoustic detector or a capacitance detector, the residue detector may be disposed inside the device cavity. In particular, when the residue detector includes an acoustic detector, the acoustic detector may be disposed in contact with the surface of the device cavity or the heater, or at least in contact with the residue on the surface of the device cavity or the heater.

[0124] In some embodiments, the case includes a case housing having a protrusion. The protrusion may be disposed to be received inside the device cavity when the aerosol generator is received in the case cavity. One or more residue detectors may be disposed on the protrusion such that when the aerosol generator is received in the case cavity, the one or more residue detectors are positioned inside the device cavity. When the case includes a housing having a first portion and a second portion movable relative to the first portion, the second portion may include the protrusion, and the protrusion may be disposed to be received inside the device cavity when the aerosol generator is received in the case cavity and the first and second portions are disposed in the closed position.

[0125] When the residue detector includes an optical detector, the case may include a light source and a photosensor. The light source may be arranged to direct light into the device cavity of the aerosol generator received within the case cavity. The photosensor may be arranged to receive light from the device cavity of the aerosol generator received within the case cavity. The optical detector preferably also includes an optical guide arranged to direct light between the optical detector and the device cavity of the aerosol generator received within the case cavity. In these embodiments, the aerosol generator configured to be received within the case cavity may include a window in a portion of the device housing that defines the device cavity. The window in the portion of the device housing that defines the device cavity may allow light from the optical detector of the case to pass into the device cavity and may allow light from the cavity to exit the device cavity and be received by the optical detector. The window may be a gap within the device housing. The window may include a material transparent to light from the optical detector. The window may be an optical guide.

[0126] In some embodiments, the case may include a button, switch, or another type of user input to initiate determination of residue within the device cavity of the aerosol generator received within the case cavity or on the heater. When the user input is activated by the user, the case controller is configured to determine a display of the amount of residue.

[0127] In some embodiments, the case may be configured to initiate determination of residue within the device cavity of the aerosol generator received within the case cavity or on the heater when the lid of the case is closed. In some embodiments, the case may be configured to initiate determination of residue within the device cavity of the aerosol generator received within the case cavity or on the heater after a predetermined period of time after the lid of the case is closed. For example, the predetermined period of time may be between about 10 seconds and about 30 seconds after the lid of the case is closed.

[0128] The case preferably comprises a residue indicator for displaying to the user the amount of determined residue within the cavity or on the heater. The residue indicator may include visual indicators such as a display or one or more lights. The residue indicator may include audible indicators such as a loudspeaker or a buzzer. Typically, the residue indicator is connected to the case controller. The case controller may be configured to send a signal to the residue indicator to indicate to the user the amount of determined residue on the aerosol generator. In some embodiments, the case controller is configured to send a signal to the residue indicator when the amount of determined residue within the cavity or on the heater exceeds a threshold. Advantageously, by providing one or more residue indicators in the case, the case controller may be able to warn the user when an unacceptable amount of aerosol-forming substrate on the aerosol generator is detected.

[0129] In some embodiments, the case controller is further configured to send a residue signal to the device controller when the indication of the amount of residue of aerosol-forming substrate determined on the aerosol generator exceeds a threshold. In these embodiments, the device controller may be configured to receive the residue signal from the case controller and, when the residue signal is received, prevent power from being supplied from the power source to the heater to heat the aerosol-forming substrate within the cavity.

[0130] The case controller may further be configured to send a signal to the device controller indicating no residue when the indication of the amount of residue of aerosol-forming substrate determined on the aerosol generator is below the threshold. In these embodiments, the device controller may be configured to receive the signal indicating no residue from the case controller and, when the signal indicating no residue is received, enable power to be supplied from the power source of the device to the heater to heat the aerosol-forming substrate within the cavity.

[0131] In some embodiments, the case controller is configured to send a cleaning signal to the device controller when an indication of the amount of residue of the aerosol-forming substrate within the cavity or on the heater exceeds a threshold. In these embodiments, the device controller is configured to supply power to the heater to raise the temperature of the heater to a first temperature sufficient to heat the aerosol-forming substrate received within the cavity to form an aerosol, receive a cleaning signal from the controller of the case, and when receiving the cleaning signal from the case controller, supply power to the heater to raise the temperature of the heater to a second temperature higher than the first temperature to thermally liberate the organic material adhered or deposited in the cavity.

[0132] By configuring the aerosol generation system such that the case controller initiates a thermal decomposition cleaning cycle of the aerosol generator, it can be ensured that the aerosol generator is received within the case when the cleaning cycle is performed. Advantageously, the case can provide additional protection to the user from the heater of the aerosol generator during the cleaning cycle when the heater is heated to the second temperature.

[0133] When the case comprises a case housing having a first part and a second part movable relative to the first part, the case controller may be configured to send a cleaning signal to the aerosol generator received within the case cavity when the first part and the second part are disposed in the closed position. Advantageously, this can ensure that the case housing substantially surrounds or encloses the aerosol generator when the thermal decomposition cleaning cycle is performed.

[0134] The case preferably includes a power source. Typically, the power source of the case is housed within the case housing. The power source of the case is preferably a DC power source. Typically, the power source of the case is a battery. The power source of the case may be a nickel-metal hydride battery, a nickel-cadmium battery, or a lithium-based battery (such as a lithium cobalt, lithium iron phosphate, or lithium polymer battery). However, in some embodiments, the power source of the case may be another form of charge storage device such as a capacitor. The power source of the case may need to be recharged. The power source of the case may have a capacity that allows for storage of sufficient energy to recharge the power source of the aerosol generating device a plurality of times, such as 10 or 20 times.

[0135] The case may further include a power transfer circuit housed within the housing. The power transfer circuit may be arranged to transfer power from the power source of the case to the power source of the device when the aerosol generating device is received within the case cavity.

[0136] When the aerosol generating device includes residue detection means, the device controller may be configured to communicate a display of the determined amount of residue via a communication link with one or more of the case, an external device, and an external server. When the case includes residue detection means, the case controller may be configured to communicate a display of the determined amount of residue via a communication link with one or more of the aerosol generating device, an external device, and an external server. The external device may be any suitable device such as a personal computer, laptop, tablet computer, or smartphone. The external server may be a remote server. In some embodiments, the system may be configured to communicate with a cloud server via the Internet. The communication link may be suitable for the flow of data from the device controller to one or more of the case, an external device, or an external server. The communication link may be suitable for the flow of data from the case to one or more of the aerosol generating device, an external device, or an external server. The communication link is preferably suitable for the bidirectional flow of data between the aerosol generating device and the case. The communication link may be suitable for the bidirectional flow of data between one or more of the aerosol generating device, the case, and an external device or an external server.

[0137] In some exemplary embodiments, the communication link is a wired communication link. In some exemplary embodiments, the communication link is a wireless communication link. The communication link preferably operates based on an interface standard. The interface standard describes one or more functional characteristics such as code conversion, line assignment, or protocol compliance, or physical characteristics such as electrical, mechanical, or optical characteristics necessary to allow information exchange between components of two or more systems or devices. Examples of suitable interface standards for communication links include, but are not limited to, the Recommended Standard 232 (RS-232) family of standards, Universal Serial Bus (USB), Bluetooth, FireWire (a brand name of Apple, Inc. for its IEEE 1394 interface), IrDA (Infrared Data Association - a communication standard for short-range data exchange by infrared), Zigbee (an application based on the IEEE 802.15.4 standard for wireless personal area networks), and other Wi-Fi standards.

[0138] At least one of the device controller and the case controller may include a communication interface, for example, at least a telemetry circuit and an antenna. More specifically, data and commands may be transmitted and received using the communication interface during uplink telemetry or downlink telemetry between one or more of the device controller, the case controller, and an external device or an external server. In at least one embodiment, the communication interface is a wireless interface that uses one or more wireless (radio frequency) data transmission protocols, for example, Bluetooth (R), Wi-Fi, any protocol in the ultra-high frequency (UHF) band, any protocol in the super-high frequency (SHF) band, low frequency, etc.

[0139] In some embodiments, the device controller includes a communication interface. In some embodiments, the case controller includes a communication interface. In some embodiments, the device controller includes a first communication interface and the case controller includes a second communication interface.

[0140] In some preferred embodiments, a controller of an aerosol generation system, such as the device controller or the case controller, may be configured to communicate a display of the amount of residue determined to an external device, such as a user's smartphone, via a short-range communication protocol such as Bluetooth (registered trademark), and the external device may be configured to communicate the display of the amount of residue determined to an external server, such as a cloud server, via a network such as the Internet.

[0141] Naturally, the aerosol generator of the first aspect of the present invention may include any of the features described above in relation to the aerosol generation system of the second aspect of the present invention. For example, the aerosol generator of the first aspect may include a controller including a communication interface.

[0142] According to a fourth aspect of the present invention, there is provided a residue detector device for detecting a residue of an aerosol-forming substrate within an aerosol generator. The residue detector device includes a detector cavity for receiving at least a portion of the aerosol generator and a residue detector disposed to detect a residue of the aerosol-forming substrate of a portion of the aerosol generator received within the detector cavity.

[0143] The residue detector of the residue detector device may be any suitable residue detector as described above in relation to the first, second, and third aspects of the present invention. In particular, suitable residue detectors include volatile organic compound (VOC) detectors, carbon dioxide detectors, optical detectors, acoustic detectors, and capacitance detectors.

[0144] The detector cavity can be of any suitable shape or size. For example, in some embodiments that include an optical detector, the cavity can have a substantially hemispherical shape so as to reflect light in all directions such that light can be directed onto as much of the surface of the aerosol generator cavity and the heater as possible. For example, in some embodiments that include a gas detector such as a carbon dioxide detector, the detector cavity can have a substantially cylindrical shape that is close to the shape and size of the proximal end of the aerosol generator such that the proximal end of the aerosol generator is closely received within the detector cavity.

[0145] One or more residue detectors of the residue detector device may be disposed at any suitable location on the detector device. It is preferred that the one or more residue detectors are disposed in or around the detector cavity.

[0146] In some embodiments, the residue detector device includes a protrusion within the detector cavity. The protrusion within the detector cavity may be configured such that when a portion of the aerosol generator is received within the detector cavity, it is received within the cavity of the aerosol generator. One or more residue detectors of the residue detector device may be disposed on the protrusion such that when a portion of the aerosol generator is received within the detector cavity, the one or more residue detectors are received within the cavity of the aerosol generator.

[0147] The residue detector device preferably includes a housing that defines the detector cavity. The detector controller is preferably the housing within the detector housing. The residue detector device preferably further includes a power source. The power source of the detector is preferably housed within the detector housing.

[0148] In some particularly preferred embodiments, the residue detector device comprises an indicator for indicating that the cavity or heater of the aerosol generator requires cleaning. The indicator may be a visual indicator such as one or more LEDs, or an audible indicator such as a buzzer. The controller may be configured to send a signal to the indicator when the indication of the amount of residue determined within the cavity of the aerosol generator or on the heater exceeds a predetermined threshold. When a signal is sent to the indicator, the indicator is activated and may warn the user that the aerosol generator requires cleaning.

[0149] The residue detector device may be similar in many aspects to the cases of the second and third embodiments of the present invention. However, typically, the residue detector device is not configured to surround or enclose the aerosol generator. The detector cavity of the residue detector device is preferably configured to receive the proximal portion of the aerosol generator, including the device cavity and the heater.

[0150] In some preferred embodiments, the residue detector device is part of a cleaning system for the aerosol generator. The cleaning system may comprise a cleaning tool such as a brush. The cleaning tool may be configured to clean the residue of the aerosol-forming substrate from the cavity and heater of the aerosol generator. The cleaning system may comprise two parts, a first part comprising the residue detector device, and a second part comprising the cleaning tool. The first and second parts may be removably fixable together.

[0151] According to a fifth aspect of the present invention, there is provided a method of operating an aerosol generating device, the aerosol generating device comprising a cavity for receiving an aerosol forming substrate, a power source, a heater, and residue detecting means, the method comprising supplying power from the power source to the heater to heat the aerosol forming substrate received in the cavity, terminating the supply of power to the heater, measuring the amount of residue in the cavity or on the heater using the residue detecting means at a predetermined time after the termination of the supply of power to the heater, and determining a display of the amount of residue of the aerosol forming substrate in the cavity or on the heater based on the measurement value from the residue detecting means.

[0152] In some embodiments, the method further comprises comparing the determined amount display of the residue of the aerosol forming substrate in the cavity or on the heater with a predetermined threshold. In some embodiments, the method further comprises transmitting the display to the user when the determined amount display of the residue of the aerosol forming substrate in the cavity or on the heater exceeds a predetermined threshold. The display transmitted from the controller to the user may include, for example, illumination of a light source, display of a message or other information on a display, or sounding of a buzzer or loudspeaker.

[0153] In some embodiments, the method further comprises supplying power to the heater to increase the temperature of the heater to thermally release the organic material adhered or deposited in the cavity or on the heater when the determined amount display of the residue of the aerosol forming substrate in the cavity or on the heater exceeds a predetermined threshold.

[0154] In some embodiments, the method further comprises preventing power from being supplied to the heater of the aerosol generating device when the determined amount display of the residue of the aerosol forming substrate in the cavity or on the heater exceeds a predetermined threshold.

[0155] Of course, the features described with respect to one aspect of the present invention can equally apply to other aspects of the present invention. In particular, the features of the residue detector described in relation to the aerosol generator are applicable to the case for the aerosol generator, and vice versa.

[0156] Here, by way of example only, embodiments of the present invention will be described with reference to the following accompanying drawings.

Brief Description of the Drawings

[0157]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0158] Figure 1 shows a schematic view of an aerosol generating device 100 according to a first embodiment of the present invention. The aerosol generating device 100 shown in Figure 1 is a device configured to receive an aerosol generating article (not shown) including a solid aerosol forming substrate and a filter wrapped together in the form of a rod like a conventional cigarette. The aerosol generating device 100 is a portable device configured to be held in a user's hand. The aerosol generating device 100 includes a housing 102 having a substantially cylindrical shape with a length of about 90 mm and a diameter of about 14 mm.

[0159] An open cylindrical cavity 104 is provided at the proximal end of the housing 102 of the device 100 to receive the aerosol forming substrate of the aerosol generating article. An elongated heater 106 in the form of a blade extends into the cavity 104 so as to penetrate into the aerosol forming substrate of the aerosol generating article received in the cavity 104. The heater 106 includes a plurality of resistive heating elements or tracks disposed on an electrically insulated polyimide substrate.

[0160] A power source 108 in the form of a lithium ion battery having a capacity of about 120 milliampere-hours is housed within the housing 102.

[0161] A controller 110 is also housed within the housing 102. The controller 110 includes a microprocessor (not shown). The controller 110 is connected to the heater 106 and the power source 108, and the controller 110 is configured to control the supply of power from the power source 108 to the heater 106.

[0162] In this embodiment, the controller 110 is configured to measure the resistance of one of the resistive heating elements of the heater 106. The electrical resistance of the resistive heating element provides an indication of the temperature of the heater 106. The controller 110 is configured to control the temperature of the heater 106 by controlling the power supplied from the power source 108 to the heater 106 based on the measured value of the resistance of the resistive heating element.

[0163] The electrical connector 112 is disposed on the distal end face of the housing 102 on the opposite side of the cavity 104. The power source 108 and the controller 110 are connected to the electrical connector 112.

[0164] According to the present invention, the aerosol generating device 100 includes residue detecting means. In this embodiment, the residue detecting means includes the configuration of the heater 106 and the controller 110. The controller is configured to measure the electrical resistance of the electrically resistive heating element of the heater 106 during a predetermined period after the supply of power to the heater 106 for heating the aerosol forming substrate has ended. In this device, the predetermined period is 30 seconds, and this time has been found to provide an appropriate length of time approximating the time it takes for the user to remove the aerosol generating article from the device after use and to disperse any remaining aerosol generated during use from the cavity.

[0165] After the predetermined period, the controller 110 is configured to supply a predetermined amount of power to the heater 106 to raise the temperature of the heater by a known amount. The controller 110 is configured to measure the resistance of the electrically resistive heating element and determine the rate of change of the resistance of the electrically resistive heating element as the temperature of the heater 106 rises by the known amount. In this embodiment, the controller 110 is configured to monitor the rate of change of the resistance of the heating element and compare the measured rate of change with a threshold value. The threshold value is a predetermined threshold value stored in a memory (not shown) of the controller 110. If the rate of change of the resistance is below the threshold value, this provides an indication that an unacceptable amount of residue of the aerosol forming substrate is present on the heater and is affecting the performance of the heater.

[0166] Figure 2 shows an exemplary graph showing an exemplary change over time in the resistance of the electrically resistive heating element of heater 106 for a given power supplied to heater 106 when residues of three different amounts of aerosol-forming substrate are provided on the surface of heater 106. As shown in Figure 2, the maximum rate of change 150 of the resistance of the heating element is measured when no residues of the aerosol-forming substrate are provided on the surface of heater 106. A slightly lower rate of change 152 of the resistance of the heating element is measured when a thin coating of residues of the aerosol-forming substrate is provided on the surface of heater 106. The minimum rate of change 154 of the resistance of the heating element is measured when a thick coating of residues of the aerosol-forming substrate is provided on the surface of heater 106. A predetermined threshold 156 for the rate of change or resistance of the heating element is also shown in Figure 2. The predetermined threshold indicates the limit of the minimum acceptable rate of change of the resistance, which indicates the maximum amount of residues of the aerosol-forming substrate that is acceptable on the heater.

[0167] Referring again to Figure 1, the aerosol generating device 100 further comprises a residue indicator 114 in the form of an LED disposed on the outer surface of the housing 102. In this embodiment, the controller 110 is configured to illuminate the LED 114 when it is determined that the measured rate of change of the resistance of the heating element is below the threshold 156. The residue indicator LED 114 provides an indication to the user that the amount of residues of the aerosol-forming substrate in the cavity and on the heater is above the acceptable level and that the heater 106 requires cleaning.

[0168] Of course, in some embodiments, the controller may be configured to prevent power from being supplied to the heater to heat the aerosol-forming substrate when it is determined that the measured rate of change of the resistance of the heating element is below the threshold.

[0169] Figure 3 shows a schematic view of an aerosol generating device 200 according to a second embodiment of the present invention. The aerosol generating device 200 is substantially similar to the aerosol generating device 100 shown in FIG. 1, and the same reference numerals are used to designate similar features. The aerosol generating device 200 shown in FIG. 3 is configured to receive an aerosol generating article (not shown) including a solid aerosol forming substrate and a filter wrapped together in the form of a rod such as a conventional cigarette. The aerosol generating device 200 is a portable device configured to be held in a user's hand. The aerosol generating device 200 comprises a housing 202 that is substantially cylindrical and has a length of about 90 mm and a diameter of about 14 mm.

[0170] An open cylindrical cavity 204 is provided at the proximal end of the housing 202 of the device 200 to receive the aerosol forming substrate of the aerosol generating article. An elongated heater 206 in the form of a blade extends into the cavity 204 so as to penetrate into the aerosol forming substrate of the aerosol generating article received within the cavity 204. The heater 206 includes a plurality of resistive heating elements or tracks disposed on an electrically insulated polyimide substrate.

[0171] The cavity 204 is substantially cylindrical and has a circular base 205 and a tubular side wall extending from the outer periphery of the base 205 to the open end of the cavity 204. The heater 206 extends into the cavity through the base 205.

[0172] A power source 208 in the form of a lithium ion battery having a capacity of about 120 milliampere hours is housed within the housing 202.

[0173] A controller 210 is also housed within the housing 202. The controller 210 includes a microprocessor (not shown). The controller 210 is connected to the heater 206 and the power source 208, and the controller 210 is configured to control the supply of power from the power source 208 to the heater 206.

[0174] The electrical connector 212 is disposed on the distal end face of the housing 202 on the opposite side of the cavity 204. The power supply 208 and the controller 210 are connected to the electrical connector 212.

[0175] According to the present invention, the aerosol generator 200 includes residue detection means. In this embodiment, the residue detection means includes a residue detector 218. The residue detector 218 is a capacitance sensor as shown in FIG. 4.

[0176] The capacitance sensor 218 includes a pair of annular electrodes 220, 222 disposed on the base 205 of the cavity 204. The annular electrodes 220, 222 are arranged concentrically and surround the heater 206. The annular electrodes 220, 222 are mutually engaged electrodes, and each electrode has a plurality of protrusions regularly spaced apart, and the protrusions of one electrode are arranged to extend into the spaces between the protrusions of the other electrode.

[0177] The first annular electrode 220 includes a plurality of protrusions 221 extending radially outward from the annular main track. The protrusions 221 of the first electrode 220 are spaced via gaps so as to provide regular spaces between adjacent protrusions 221. The second annular electrode 222 includes a plurality of protrusions 223 extending radially inward from the annular main track. The protrusions 223 of the second electrode 222 are spaced via gaps so as to provide regular spaces between adjacent protrusions 223. The number of protrusions 221 of the first electrode 220 is the same as the number of protrusions 223 of the second electrode 222. The protrusions 221 of the first electrode 220 are substantially identical to the protrusions 223 of the second electrode 222 and have the same length and width. The protrusions 221 of the first electrode 220 extend into the spaces between adjacent protrusions 223 of the second electrode 222, and the protrusions 223 of the second electrode 222 extend into the spaces between adjacent protrusions 221 of the first electrode 220.

[0178] The first electrode 220 and the second electrode 222 are generally spaced apart by a gap around the periphery of the electrodes. The second electrode 220 has a diameter substantially equal to the diameter of the base 205 of the cavity 204 such that the second electrode substantially surrounds the base 205 of the cavity 204. In this arrangement, the capacitance residue sensor 218 is arranged to detect residues of the aerosol-forming substrate at the outer periphery of the base 205 of the cavity 204.

[0179] The controller 210 is configured to supply an alternating voltage to the first electrode 220 such that the first electrode 220 is configured as a drive electrode. The controller 210 is further configured to measure the voltage of the second electrode 222 such that the second electrode 222 is configured as a sense electrode. The controller 210 is configured to determine the capacitance of the capacitor formed by the first electrode 220 and the second electrode 222 using the voltage measured at the second electrode 222.

[0180] When the oscillation voltage is supplied to the first electrode 220, an electric field is established between the first electrode 220 and the second electrode 222 across the space between the electrodes. The electric field between the first electrode 220 and the second electrode 222 includes a fringing electric field that extends from the base 205 into the cavity 204. The fringing electric field impinges on residues of the aerosol-forming substrate disposed on the base 205 of the cavity 204 above and in the vicinity of the capacitance sensor 218. The capacitance of the capacitor formed by the first electrode 220 and the second electrode 222 changes as a result of the dielectric properties of the residues of the aerosol-forming substrate when the fringing electric field impinges on the residues of the aerosol-forming substrate disposed on the base 205 of the cavity 204, and then the voltage of the second electrode 223 measured by the controller 210 changes. The amount of residues of the aerosol-forming substrate on the base 205 of the cavity 204 is related to the magnitude of the change in the capacitance of the capacitance residue sensor 218. Thus, the capacitance of the capacitance residue sensor 218 can provide an indication of the amount of residues of the aerosol-forming substrate on the base 205 of the cavity 204.

[0181] In this embodiment, the aerosol generating device 200 further comprises an indicator in the form of a buzzer 214 for providing an audible alarm to the user when it is determined that the amount of residue of the aerosol-forming substrate in the cavity 204 exceeds an acceptable level.

[0182] The aerosol generating device 200 comprises a switch 215 that can be pressed by the user to prompt the controller 210 to measure the capacitance of the capacitance residue sensor 218 and determine a display of the amount of residue of the aerosol-forming substrate in the cavity 204. The controller 210 is configured to compare the determined capacitance of the capacitance residue sensor 218 with a predetermined threshold. When the determined capacitance exceeds the predetermined threshold, the controller determines that the amount of residue of the aerosol-forming substrate in the cavity 204 exceeds an acceptable level. Thus, when the determined capacitance exceeds the predetermined threshold, the controller 210 is configured to send a signal to the buzzer 214 to activate the buzzer 214 and warn the user that the cavity 204 needs cleaning.

[0183] In this embodiment, the controller 210 is further configured to prevent power from being supplied to the heater 206 when the determined capacitance exceeds a predetermined threshold. Thus, the user needs to clean the cavity 204 before being able to use the aerosol generating device again. When the cavity 204 is cleaned, the user needs to press the button 215 for a second time so that the controller 210 determines the amount of residue of the aerosol-forming substrate in the cavity 204 over a second period of time. If the controller 210 determines that the amount of residue of the aerosol-forming substrate in the cavity is within an acceptable level, the controller 210 is configured to enable the supply of power from the power supply 208 to the heater 206 to heat the aerosol-forming substrate.

[0184] In this embodiment, the capacitance residue sensor is disposed on the base of the cavity. However, of course, in other embodiments, the capacitance residue sensor may be disposed on one or more sidewalls of the cavity. The first electrode and the second electrode may have interengaged protrusions that extend on the sidewall of the cavity in a direction between the proximal end and the distal end of the cavity. Such a capacitance sensor disposed on the sidewall of the cavity can be configured to detect residues of the aerosol-forming substrate on or near the sidewall of the cavity.

[0185] Figure 5 shows the proximal end of an aerosol generating device 300 according to another embodiment of the present invention. The aerosol generating device 300 is substantially similar to the aerosol generating device 100 shown in FIG. 1, and like reference numerals are used to designate like features. The aerosol generating device 300 shown in FIG. 5 is configured to receive an aerosol generating article (not shown) and includes a generally cylindrical housing 302 having a length of about 90 mm and a diameter of about 14 mm. An open cavity 304 is provided at the proximal end of the housing 302 for receiving the aerosol-forming substrate of the aerosol generating article. An elongated heater 306 in the form of a blade extends into the cavity 304 so as to penetrate into the aerosol-forming substrate of the aerosol generating article received in the cavity 304. The heater 306 includes a plurality of resistive heaters or tracks disposed on an electrically insulated polyimide substrate.

[0186] The cavity 304 is substantially cylindrical and has a circular base 305. The heater 306 extends into the cavity 304 through a slot in the base 305.

[0187] In this embodiment, the housing 302 includes an extractor 303 at the proximal end of the device 300. The extractor 303 defines a cavity 304 and is removably receivable at the distal portion of the housing 302. The extractor 303 includes a substantially tubular side wall and a base portion that extends inwardly from the tubular side wall to define a base 305 of the cavity 304. The base portion includes a slot for receiving the heater 306 when the extractor is received on the distal portion of the housing 302. The extractor 303 is configured to facilitate removal of the aerosol-generating article from the heater 306. Removal of the extractor 303 in the proximal direction from the distal portion of the housing 302 removes the aerosol-generating article received within the cavity 304 from the heater 306.

[0188] A power source (not shown), in the form of a lithium-ion battery having a capacity of about 120 milliampere-hours, is housed within the housing 302.

[0189] A controller 310 is also housed within the housing 302. The controller 310 includes a microprocessor (not shown). The controller 310 is connected to the heater 306 and the power source, and the controller 310 is configured to control the supply of power from the power source to the heater 306.

[0190] According to the present invention, the aerosol-generating device 300 comprises residue detection means. In this embodiment, the residue detection means includes an optical residue detector. The optical residue detector comprises a light source 320 in the form of an LED configured to emit substantially white light, and a light sensor 322 in the form of a photodiode. The LED 320 and the photodiode 322 are mounted on both sides of the controller 310 such that the LED 320 and the photodiode 322 are located on both sides of the device 300.

[0191] The optical residue detector further includes a pair of optical guides 324, 326. The pair of optical guides 324, 326 are disposed on both sides of the extractor 303 at the distal portion of the extractor 303 that overlaps with the distal portion of the housing 302 when the extractor 303 is received on the distal portion of the housing 302.

[0192] The first optical guide 324 is disposed to be aligned with the LED 320 when the extractor 303 is received on the distal portion of the housing 302. The first optical guide 324 directs light from the LED into the cavity 304 substantially along the surface of the base 305 of the cavity 304.

[0193] The second optical guide 326 is disposed to be aligned with the photodiode 326 when the extractor 303 is received on the distal portion of the housing 302. The second optical guide 326 directs light from the cavity 304 to the photodiode 326, specifically from the base 305 of the cavity 304.

[0194] In this arrangement, the optical residue detector is configured to direct light of a wide wavelength into the cavity 304 substantially along the base of the cavity 304 and direct light from the cavity 304 to the photodiode 322. Thus, the optical residue detector is configured to detect the presence of residues of the aerosol-forming substrate in the cavity 304, specifically at the base 305 of the cavity 304.

[0195] The controller 310 of the aerosol generator 300 is configured to determine a display of the amount of residues of the aerosol-forming substrate in the cavity 304 and on the heater 306 from the measured value of the intensity of the incident light on the photodiode 322. The controller 310 is generally configured to use such residue determination in a manner similar to that of the controller 210 of the device 200 described above and shown in FIG. 4.

[0196] Figure 6 shows a heater assembly 400 for an aerosol generator according to another embodiment of the present invention. In this embodiment, the heater assembly 400 includes a plurality of resistive heating elements 402 disposed on an electrically insulated polyimide substrate 404. The electrically insulated substrate 404 and the resistive heating elements 402 are formed within an elongated heating blade configured to be inserted into an aerosol forming substrate. The proximal end of the electrically insulated substrate 404 is tapered towards the tip to facilitate insertion of the heater into the aerosol forming substrate.

[0197] According to the present invention, the heater assembly 400 includes a pair of optical waveguides 424, 426 for an optical residue detector. The optical waveguides 424, 426 are configured in the same manner as the optical waveguides 324, 326 of the device 300 described above and shown in FIG. 5. The optical waveguides 424, 426 are disposed along a distal portion of the electrically insulated substrate 404 where the resistive heating elements 402 are not disposed. The distal portion of the electrically insulated substrate 404 and the optical waveguides 424, 426 are overmolded with a high temperature plastic material to fix the optical waveguides 424, 426 to the electrically insulated substrate 404 and provide a mount 405 for fixing the heater assembly 400 to the housing of the aerosol generator.

[0198] When the heater assembly 400 is disposed in the aerosol generator, the first optical waveguide 424 is disposed to direct light from a light source of the optical residue detector of the device into the cavity of the device at the base of the cavity, and the second optical waveguide 246 is disposed to direct light from the base of the cavity of the device to a photodetector of the optical residue detector of the device. The heater assembly arrangement shown in FIG. 4 can provide a simple, reliable, and relatively inexpensive method of providing an aerosol generator having an optical residue detector.

[0199] Figure 7 shows an aerosol generation system comprising a case 500 according to another embodiment of the present invention. Figure 7 also shows the aerosol generator 100 shown in FIG. 1 received within the case 500.

[0200] The case 500 shown in FIG. 7 is a portable case having a case housing 502 that is shaped and sized to be held in a user's hand and to fit into a pocket of the user's clothing. The housing 502 is generally a rectangular cube having a length of about 20 mm, a width of about 50 mm, and a height of about 110 mm.

[0201] The case housing 502 defines a case cavity 504 for receiving an aerosol generator. In FIG. 7, the aerosol generator 100 of FIG. 1 is received within the case cavity 504. The case cavity 504 is open at the proximal end of the case housing 502 to receive the aerosol generator and is closed at the distal end opposite the proximal end of the case housing 502. A lid 505 is rotatably attached to the proximal end of the case housing 502 via a hinge and is configured to rotate relative to the case housing 502 between an open position and a closed position. When the lid 505 is in the closed position, the lid 505 is disposed to cover the open end of the case cavity 504. In the closed position, the case housing 502 and the lid 505 substantially surround or enclose the aerosol generator 100 when the aerosol generator 100 is received within the case cavity 504. When the lid 505 is in the open position, the open end of the case cavity 504 is not covered, and the aerosol generator 100 may be inserted into and removed from the case cavity 504.

[0202] A power source 506 of the case in the form of a lithium-ion battery having a capacity of about 2900 milliampere-hours (mAh) is housed within the case housing 502.

[0203] An electrical connector 508 is disposed at the closed distal end of the case cavity 504 for receiving the aerosol generator 100. The electrical connector 508 connected to the power source 506 of the case is disposed to electrically connect to a corresponding electrical connector 112 of the aerosol generator 100 when the aerosol generator is fully received within the chamber 504.

[0204] The case controller 510 is also housed within the case housing 502. The case controller 510 is connected to the case power supply 506 and the electrical connector 508 and is configured to control the supply of power from the case power supply 506 to the electrical connector 508.

[0205] The case controller 510 and the electrical connector 508 are configured to supply power to the aerosol generator 100 received within the case cavity 504 and are also configured to communicate with the aerosol generator 100 to transfer data to and receive data from the aerosol generator 100.

[0206] The case controller 510 includes a microprocessor (not shown) and also includes a communication interface (not shown). In this embodiment, this communication interface includes a telemetry circuit and an antenna for two-way communication with an external device or server. In this embodiment, the communication interface is a wireless interface that communicates with an external device or server using the Bluetooth® protocol. Typically, the communication interface is configured to communicate with the user's smartphone.

[0207] According to the present invention, the case 500 includes a residue detector 518. The residue detector 518 is disposed on the lid 505 of the case 500, directly above the proximal end of the case cavity 504. At this position, when the aerosol generator 100 is received within the case cavity 504 and the lid 505 is in the closed position, the residue detector 518 is disposed above the open end of the device cavity 104 of the aerosol generator 100.

[0208] In some embodiments, the lid 505 of the case 500 may include a protrusion that is disposed to be received within the device cavity 504 when the aerosol generator 100 is received within the case cavity 504 and the lid 505 is in the closed position. In these embodiments, the residue detector 518 may be disposed on the protrusion.

[0209] In this embodiment, the residue detector 518 is a VOC detector. Accordingly, volatile organic compounds released from residues of the aerosol-forming substrate within the device cavity 104 or on the heater 106 can be detected by the VOC detector 518 of the case 500. The residue detector 518 is electrically connected to the case controller 510 via a flexible circuit (not shown). The flexible circuit enables a robust electrical connection between the residue detector 518 and the case controller 510 while also enabling rotation of the lid 505 relative to the case housing 502.

[0210] The case controller 510 is configured to obtain readings from the residue detector 518 for a predetermined period after the lid 505 has moved to the closed position. In this embodiment, the predetermined period is 10 seconds. The case controller 510 is configured to determine a display of the amount of residue on the device cavity 104 or the heater 106 based on one or more readings from the residue detector. Specifically, in this embodiment, the case controller 510 is configured to compare one or more readings from the residue detector 518 to a predetermined threshold. When one or more readings from the residue detector 518 exceed the predetermined threshold, the case controller 510 is configured to determine that the amount of residue of the aerosol-forming substrate on the device cavity 104 and the heater 106 exceeds an acceptable level. When one or more readings from the residue detector 518 exceed the predetermined threshold, the case controller 510 is configured to initiate a cleaning cycle of the aerosol generating device 100.

[0211] When one or more readings from the residue detector 518 exceed the predetermined threshold, the case controller 510 is configured to transmit a cleaning signal to the device controller 110 of the aerosol generating device 100 via a communication link through the electrical connectors 508, 112.

[0212] In this embodiment, the device controller 110 is configured to receive a cleaning signal from the case controller 510. When the device controller 110 receives the cleaning signal from the case controller 510, the device controller 110 is configured to supply power to the heater 106 in a cleaning cycle. In the cleaning cycle, the device controller 110 supplies power to the heater to raise the temperature of the heater sufficiently to thermally release the organic materials adhered or deposited in the device cavity 104 or on the heater. 106.

[0213] After each determination of the indication of the amount of residue in the device cavity 104 or on the heater 106, the case controller 510 is further configured to output a residue signal to the communication interface of the case controller 510 based on the determination. The communication interface is configured to communicate the residue signal to the user's smartphone via a communication link using the Bluetooth (registered trademark) protocol.

[0214] It is assumed that a program may be stored in the user's smartphone to analyze the residue information in the residue signal. In some embodiments, the program stored in the user's smartphone may not be configured to analyze the data received in the residue signal. Instead, the data or signal may be configured to be transferred to an external server such as a cloud server for analysis.

[0215] In some embodiments, the case 500 may further include a graphical display on the outer surface of the case housing 502. The case controller 510 may be further configured to display the residue amount information to the user on the display based on the determined indication.

[0216] In some embodiments, the case controller may not be configured to initiate residue detection for a predetermined period after the lid has moved to the closed position. Instead, a switch may be provided on the case for the user to activate to initiate residue detection. In these embodiments, the user may determine when to initiate residue detection and the cleaning cycle.

[0217] FIG. 8 shows a proximal portion of an aerosol generation system comprising a case 600 according to another embodiment of the present invention and the aerosol generator 100 of FIG. 1 received within the case 600. The case 600 shown in FIG. 8 is substantially similar to the case 500 shown in FIG. 7, and like reference numerals are used to denote like features. The case 600 is a portable charging case having a case housing 602 shaped and sized to be held in the user's hand and to fit into a pocket of the user's clothing.

[0218] The case housing 602 defines a case cavity 604 and includes a lid 605, both of which are identical to the case cavity 504 and lid 505 described above in connection with the embodiment of FIG. 7. A case power source 606 in the form of a lithium-ion battery having a capacity of approximately 2900 milliampere-hours (mAh) is housed within the case housing 602. An electrical connector (not shown) is also disposed at the distal end of the case cavity 604 for receiving the aerosol generator, as described above in connection with the embodiment of FIG. 7. A case controller 610 is housed within the case housing 602 and is substantially disposed and configured as described above in connection with the embodiment of FIG. 7.

[0219] According to the present invention, the case 600 includes a residue detector. In this embodiment, the residue detector is an optical residue detector comprising a light source 620 in the form of an LED configured to emit substantially white light, a light sensor 622 in the form of a photodiode, and two light guides 624, 626.

[0220] In this embodiment, the device housing 102 of the aerosol generator includes a window 107 at the base of the device cavity 104. The window 107 allows light to move through the device housing 102 and into and out of the device cavity 104. In this embodiment, the window 107 is made of a transparent high-temperature plastic material. However, in other embodiments, the window may be a slot or space within the device housing 104 that allows light to move into and out of the device cavity 104.

[0221] The optical light guides 624, 627 of the optical residue detector of the case 600 are arranged to direct light inside and outside the window 107 of the device housing 102 when the aerosol generator 100 is received within the case cavity 604. The first light guide 624 is arranged to direct light from the LED 620 into the device cavity 104 through the window 107 of the device housing 102. The second light guide 626 is arranged to direct light from the device cavity 104 through the window 107 of the device housing 102 to the photodiode 622.

[0222] The case controller 610 is configured to determine a display of the amount of residue of the aerosol-forming substrate within the device cavity 104 and on the heater 106 based on the readings from the photodiode 622.

[0223] FIG. 9 shows a residue detector device 700 according to another embodiment of the present invention. The residue detector device 700 includes a residue detector body 702 that defines a substantially hemispherical detector cavity 704. The detector cavity 704 is shaped and sized to receive the proximal portion of an aerosol generator, such as the aerosol generator 100 of the embodiment of FIG. 1, as shown in FIG. 9.

[0224] According to the present invention, the residue detector device 700 includes a residue detector. In this embodiment, the residue detector is an optical residue detector that includes a light source 706 in the form of an LED configured to emit substantially white light, and a light sensor 708 in the form of a photodiode.

[0225] LED 706 is positioned towards the edge of the hemispherical detector cavity 704 and is arranged to direct light towards the opposite side of the detector cavity 704. A reflective coating for reflecting light from the LED 708 is provided on the surface of the detector cavity 704. The hemispherical shape of the detector cavity 704 results in incident light on the surface of the cavity 704 being reflected in all directions, such that when the proximal end of the aerosol generator 100 is received within the detector cavity 704, light from the LED 706 can be directed towards the device cavity 104 of the aerosol generator 100 and most of the surface of the heater 106.

[0226] The photodiode 708 is disposed at one end of a channel 710 that extends centrally through the detector housing 702 from the surface of the detector cavity 704 to the photodiode 708. The channel 710 is configured to allow light to move from the detector cavity 704 to the photodiode 708. In this embodiment, the channel is an empty channel, although in some embodiments, the channel may include an optical guide such as an optical fiber.

[0227] The residue detector device 700 further includes a power supply 712 and a controller 714 housed within the detector housing 702. The residue detector device 700 also includes a switch 716 and a visual indicator 716 in the form of an LED on the outer surface of the detector housing 702.

[0228] The detector controller 714 is configured to control the supply of power from the detector power supply 712 to the LED 706 and the photodiode 708 of the optical residue detector, and the supply of power to the LED of the visual indicator 716. The detector controller 714 is further configured to irradiate the LED 706 of the optical residue detector and obtain a reading value from the photodiode 708 when the user presses the switch 716. The controller is configured to determine a display of the amount of residue on the aerosol forming substrate of the device cavity 104 and the heater 106 of the aerosol generator 100 received in the detector cavity 704 based on the signal from the photodiode 708. If the determined display of the amount of residue exceeds a predetermined threshold value stored in the memory of the detector controller 714, the detector controller 714 irradiates the visual indicator LED 716 to warn the user that the amount of residue on the aerosol forming substrate on the device cavity 104 and the heater 106 exceeds an acceptable level and that the aerosol generator 100 needs to be cleaned.

[0229] Of course, in other embodiments, the residue detector device may include other residue detectors. For example, the residue detector device may include one or more of a VOC detector and a carbon dioxide detector. In other embodiments, the residue detector device may be part of a cleaning system. The cleaning system may include the residue detector device and a cleaning tool such as a brush. The cleaning tool and the residue detector device may be removably fixable together. Coupling means may be provided to removably fix the cleaning tool and the residue detector device together.

Claims

1. An aerosol generating device, comprising: a cavity for receiving an aerosol generating article containing an aerosol forming substrate; a heater disposed to heat the aerosol forming substrate received in the cavity; a power source; residue detection means for detecting residue of the aerosol forming substrate in the cavity or on the heater; a controller, configured to control the supply of power from the power source to the heater for heating the aerosol forming substrate received in the cavity, receive a signal indicating the amount of residue of the aerosol forming substrate in the cavity or on the heater from the residue detection means, determine the amount of residue of the aerosol forming substrate in the cavity or on the heater based on one or more signals received from the residue detection means, and further determine whether the determined amount of residue of the aerosol forming substrate exceeds a threshold value, an aerosol generating device comprising a controller.

2. The aerosol generating device according to claim 1, wherein the controller is further configured to prevent power from being supplied from the power source to the heater to heat the aerosol forming substrate in the cavity when the determined amount of residue of the aerosol forming substrate exceeds the threshold value.

3. The aerosol generating device according to claim 1 or 2, wherein the heater is an elongated heater disposed to be inserted into the aerosol generating article when the aerosol generating article is received in the cavity and the heater includes a resistive heating element.

4. The residue detection means, wherein the controller measures the resistance of the resistive heating element, The aerosol generating device according to claim 3, comprising a configuration of the controller configured to determine an amount of residue of the aerosol-forming substrate in the cavity or on the heater based on the measured resistance of the resistive heating element.

5. The controller is configured to supply power from the power source to the heater to heat the aerosol-forming substrate received in the cavity, end the supply of power to the heater for heating the aerosol-forming substrate received in the cavity, measure the resistance of the resistive heating element of the heater after a predetermined time, The aerosol generating device according to claim 4, further configured to determine an amount of residue of the aerosol-forming substrate on the heater based on the measured resistance of the resistive heating element.

6. Determining the amount of residue of the aerosol-forming substrate in the cavity is based on the measured rate of change of resistance of the resistive heating element, the aerosol generating device according to claim 4 or 5.

7. The controller is configured to determine characteristics of a user's smoking from the measured resistance of the heating element, The aerosol generating device according to claim 4, configured to determine an amount of residue of the aerosol-forming substrate in the cavity or on the heater based on the determined characteristics of the user's smoking.

8. The determined characteristics of the user's smoking are one or more of a volume of smoking and a duration of smoking, and determining the amount of residue of the aerosol-forming substrate in the cavity or on the heater is based on a change over time of the determined characteristics of the user's smoking, the aerosol generating device according to claim 7.

9. The aerosol generating device according to claim 1, 2 or 3, wherein the residue detecting means includes residue detecting means disposed in or around the cavity.

10. Determining the amount of residue of the aerosol-forming substrate in the cavity is based on a signal received from the residue detection means during at least a predetermined period after the end of the supply of power from the power supply to the heater for heating the aerosol-forming substrate in the cavity. The aerosol generator according to claim 9.

11. The aerosol generator according to claim 9 or 10, wherein the residue detection means includes at least one of a volatile organic compound (VOC) detector, an optical detector, a capacitor, and an acoustic detector.

12. The residue detection means includes an optical detector, and the optical detector includes a light source arranged to direct light into the cavity and a light sensor arranged to receive light from the cavity. The aerosol generator according to claim 11.

13. An aerosol generation system, An aerosol generator, An apparatus cavity for receiving an aerosol-generating article containing an aerosol-forming substrate, A heater arranged to heat the aerosol-forming substrate received in the apparatus cavity, A power supply for the apparatus, and, An apparatus controller configured to control the supply of power from the power supply of the apparatus to the heater for heating the aerosol-forming substrate received in the apparatus cavity. An aerosol generator including, A case for receiving the aerosol generator, wherein the case has, A case cavity for receiving the aerosol generator, A residue detector arranged to detect residue of the aerosol-forming substrate in the apparatus cavity or on the heater when the aerosol generator is received in the case cavity, and, A case controller, Receiving, from the residue detector, a signal indicating the amount of residue of the aerosol-forming substrate within the device cavity or on the heater, A case controller configured to determine the amount of residue of the aerosol-forming substrate within the device cavity or on the heater based on the signal received from the residue detector, and further to determine whether the determined amount of residue of the aerosol-forming substrate exceeds a threshold, and a case including the case controller, an aerosol generation system comprising.

14. The case controller is, Comparing the determined amount of residue of the aerosol-forming substrate within the device cavity or on the heater with the threshold, When the determined amount of residue of the aerosol-forming substrate within the device cavity or on the heater exceeds the threshold, further configured to transmit a cleaning signal to the device controller of the aerosol generator, The device controller is, Supplying power to the heater to raise the temperature of the heater to a first temperature sufficient to form an aerosol from the aerosol-forming substrate received within the device cavity, Receiving a cleaning signal from the case controller of the case, When receiving a cleaning signal from the case controller, supplying power to the heater to raise the temperature of the heater to a second temperature higher than the first temperature to thermally release organic materials adhering or deposited within the device cavity or on the heater, the aerosol generation system according to claim 13, further configured as such.

15. A residue detector device for detecting residue of an aerosol-forming substrate within an aerosol generator, A residue detector cavity for receiving at least a portion of the aerosol generator, A residue detector arranged to detect a residue of an aerosol forming substrate on the portion of the aerosol generator received within the residue detector cavity; A controller, receives from the residue detector a signal indicative of the amount of residue of the aerosol forming substrate on the portion of the aerosol generator received within the residue detector cavity, and is configured to determine, based on the signal received from the residue detector, the amount of residue of the aerosol forming substrate on the portion of the aerosol generator received within the residue detector cavity, and further to determine whether the determined amount of residue of the aerosol forming substrate exceeds a threshold value. A residue detector device comprising a controller.

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