Method for determining the dielectric response of an aerosol-generating article

Abstract

The aerosol generating device (10) comprises a first terminal (42) and a second terminal (44) disposed within the heating chamber (18) to contact different portions of the aerosol generating article (100). An alternating voltage is applied between the first and second terminals (42, 44) and the characteristics of the current flowing therebetween are measured. The characteristics are used to determine the dielectric response of the aerosol generating article (100) at the applied frequency. The dielectric response includes both conductive and capacitive components and may be used to identify the condition of the aerosol generating article (100), for example, whether it is inserted correctly or the amount of volatile substance, such as nicotine, it contains. By comparing the dielectric response before and after the device (10) is used, it is possible to estimate the amount of volatile substance inhaled by a user of the device (10).

Description

TECHNICAL FIELD

[0001] The present disclosure generally relates to an aerosol-generating device for heating an aerosol-generating substrate to generate an aerosol for inhalation by a user of the aerosol-generating device. The present disclosure is particularly applicable to portable (handheld) aerosol-generating devices. Such devices heat an aerosol-generating substrate, for example tobacco or other suitable material, by conduction, convection, and / or radiation rather than by combustion, to generate an aerosol for inhalation by a user. BACKGROUND ART

[0002] In recent years, the popularity and use of risk reduction or risk modification devices (also known as aerosol-generating devices or vapor-generating devices) has grown rapidly as an alternative to the use of conventional tobacco products. Various devices and systems are available that heat or warm an aerosol-generating substrate to generate an aerosol for inhalation by a user.

[0003] Commonly available risk reduction or risk modification devices are substrate-heated aerosol-generating devices or so-called heated non-combustion devices. This type of device generates an aerosol or vapor by heating the aerosol-generating substrate to a temperature typically in the range of 150°C to 300°C. Heating the aerosol-generating substrate to a temperature within this range without burning the aerosol-generating substrate typically generates a vapor that cools and condenses to form an aerosol for inhalation by a user of the device.

[0004] Currently available aerosol generating devices can heat an aerosol generating substrate using one of several different methods. One such approach employs an induction heating system. In such a device, an induction coil is provided in the device, and an induction-heatable susceptor is provided to heat the aerosol generating substrate. When the user operates the device, electrical energy is supplied to the induction coil, which subsequently generates an alternating current electromagnetic field. The susceptor couples with this electromagnetic field to generate heat, which is transferred (e.g., by thermal conduction) to the aerosol generating substrate, and when the aerosol generating substrate is heated, an aerosol is generated. Another approach employs a resistance heating system in which current is supplied directly to a heater element. The heating element generates heat that is transferred to the aerosol generating substrate, for example, by conduction. The susceptor or heating element may surround the aerosol generating substrate and transfer heat to the outer surface of the aerosol generating substrate. Alternatively, the susceptor or heating element may be in the form of a blade embedded in the aerosol generating substrate when the aerosol generating substrate is inserted into the aerosol generating device.

[0005] In most such aerosol generating devices, the heater operates in a predetermined manner when commanded to start, for example, in response to the user pressing a start button, or in response to the device detecting, via an airflow sensor, that the user has inhaled a puff through the device. Optimal operation is therefore determined by the user selecting the appropriate aerosol generating substrate and correctly inserting it into the aerosol generating device. There is a demand for "smarter" aerosol generating devices that can detect the characteristics or state of the inserted substrate and use the detected state or characteristics to improve the device's operation or provide relevant information to the user.

[0006] A published patent application, International Publication No. 2017 / 051006A1, discloses an aerosol generating device comprising a power source, at least one heater, and a cavity for receiving an aerosol generating article. The device further comprises a first electrode and a second electrode spaced apart from the first electrode, such that at least a portion of the aerosol generating article is received between them. The device's controller is configured to terminate the power supply to the heater when a measured electrical load between the first and second electrodes exceeds a predetermined threshold. The electrical load may comprise at least one of a resistive load and a capacitive load. It is stated that a change in the measured electrical load between the first and second electrodes provides an indicator of the amount of one or more volatile compounds remaining in the aerosol generating article. [Overview of the project] [Means for solving the problem]

[0007] According to a first aspect of this disclosure, an aerosol generating device, A heating chamber configured to receive an aerosol-generating article, A first terminal and a second terminal, which are arranged in the heating chamber such that when an aerosol generating article is received into the heating chamber, the first and second terminals each come into contact with different parts of the aerosol generating article, comprising: A method for operating an aerosol generating device, (a) Inserting the aerosol-generating article into the heating chamber, (b) Applying an AC voltage at the applied frequency between the first and second terminals, (c) Measuring the characteristics of the current flowing between the first and second terminals while an AC voltage is applied, (d) Using the measured characteristics of the current, determine the dielectric response of the aerosol-generating article at the applied frequency.

[0008] The dielectric response can be expressed in complex form as Y = G + iωC, where Y represents admittance and G represents conductance, and i 2 = -1, where ω = 2πf is the angular frequency and C is the capacitance. It is known that as the moisture level in tobacco increases, both the real and imaginary parts of the admittance increase. The dielectric response therefore indicates the moisture level in tobacco at any given frequency. Water is expected to play an unbalanced role in the dielectric response due to its large dielectric constant, but the presence or absence of wetting agents and other volatile substances is expected to contribute to the change in admittance when the tobacco material is heated.

[0009] The measured characteristics of the current may include the current amplitude and the phase shift between voltage and current. These quantities are easy to measure and can be used to represent the current as a complex number. From the complex number expressed in terms of amplitude and phase, the real and imaginary components can be easily derived, which is equivalent to the transformation between polar and Cartesian coordinates. By comparing the complex current with the applied (real) voltage, the dielectric response (complex admittance) can be determined.

[0010] The step of identifying the dielectric response preferably includes identifying both the conductive and capacitive components of the dielectric response. While examples in the prior art have used DC or low-frequency voltages to measure only resistance or conductance, or high-frequency voltages to measure only capacitance, the present invention prefers to operate at an intermediate frequency such that both the conductive and capacitive components make a non-negligible contribution to the identified dielectric response. Since both the real and imaginary components of admittance carry information about the content of volatile substances in the substrate, more information can be derived by measuring complex quantities at a convenient intermediate application frequency. This frequency can be selected as the frequency at which the dielectric response is most sensitive to tobacco changes that occur during device use. The intermediate frequency may also be more convenient to generate and process using low-cost electronic equipment.

[0011] Preferably, the applied frequency is in the range of 100 Hz to 1 MHz. More preferably, the applied frequency is in the range of 1 kHz to 100 kHz. Since induction heating generally operates in a similar frequency range, techniques for generating such frequencies in aerosol generating devices already exist, and it may be possible to share some electronic components between the heating circuit and the circuit for determining the dielectric response.

[0012] In one variation of the method according to the present invention, steps (b) and (c) are performed at different applied frequencies, and then step (d) includes determining the dielectric response of the aerosol-generating article using the measured characteristics of the current at each applied frequency. Since the contributions of the real and imaginary components to the dielectric response are different at different frequencies, performing the determination of the dielectric response at different frequencies provides independent measurements of those components and allows for a reduction in errors.

[0013] As explained earlier, water present in the substrate is expected to contribute most significantly to its dielectric response due to its high dielectric constant. While knowing the water content of the substrate can be useful, the amount of other volatile substances, such as nicotine, is often more important. As a first approximation, it is assumed that the water content in the substrate is a good indicator of the amount of volatile substances. However, it is desirable to be able to determine the volatile substance content independently. Water and other volatile substances may contribute differently to the admittance of the substrate at different applied voltage frequencies, and therefore, performing the determination of the dielectric response at different frequencies provides a possible method for distinguishing the volatile substance content in the substrate from the water content.

[0014] A temperature sensor may be provided to measure the temperature of an aerosol-generating article, thereby allowing the measured temperature to be used in conjunction with the measured characteristics of the current to determine the dielectric response of the aerosol-generating article. Since it is known that the dielectric response is partially temperature-dependent, measuring the temperature allows for correction, enabling specific, more reliable comparisons performed at different times or under different conditions. This is particularly important when determining the dielectric response while the aerosol-generating article is being heated.

[0015] The identified dielectric response may be used to identify the state of the aerosol-generating article, and a signal may be output to indicate the state of the article to the user. Additionally or alternatively, the aerosol-generating device may be controlled in a manner that corresponds to the state of the article.

[0016] In one embodiment, the method for identifying the dielectric response of an aerosol-generating article may actually identify a condition in which the article is improperly inserted into the heating chamber. In such a case, the device may output a signal to the user indicating the improper insertion and / or prevent the device's heater from operating.

[0017] In another embodiment, the method may identify that an aerosol-generating article is unsuitable for use in the device, for example, because its volatile substances have been depleted as a result of the article having already been used. In this case as well, the device may be able to output a signal to the user indicating the condition of the article and / or prevent the device's heater from operating. Alternatively, the operation of the device, such as its operating temperature, may be adapted to compensate for the low volatile substance content of the article.

[0018] The admittance between the first and second terminals is affected not only by the substrate but also by the presence of any residue or other contaminants in the heating chamber. Therefore, if the determination of the dielectric response yields an unexpected result, this may be interpreted as an indication that the device requires cleaning. This information may also be communicated to the user by signal or used to control or prevent the operation of the device.

[0019] Another variation of the method according to the present invention is to perform steps (b) to (d) after inserting an aerosol-generating article into a heating chamber to identify a first dielectric response, then to apply heat to the aerosol-generating article in the heating chamber, for example, during a smoking session, and then to repeat steps (b) to (d) to identify a second dielectric response. The second dielectric response may be compared with the first dielectric response to identify a change in the state of the article, and the device may output a signal indicating a change in the state of the article, or the aerosol-generating device may be controlled in a manner corresponding to the change in the state of the article.

[0020] In a typical embodiment, the change of state of the article is the depletion of volatile substances within the article. As a result of this modification of the method, the article may be specified to be used up and no longer usable.

[0021] A preferred method according to the present invention involves using identified state changes of an article to estimate the amount of at least one volatile substance inhaled by a user of the device between identified first and second dielectric responses. The at least one volatile substance may include nicotine, and it is of great interest to many users of an aerosol generating device to be able to identify how much nicotine (or other substance) they consumed during a smoking session, for example, if the user is trying to control or reduce their intake of the substance. It may also be of interest to the manufacturer of the device or aerosol generating article to know how much volatile substance is consumed during real-world use. The device may be configured to transmit data to a remote location, such as a smartphone, and from there relayed to the manufacturer. Alternatively, the data may be stored in the device for subsequent retrieval.

[0022] A possible further step in this method includes recording the number of puffs inhaled by the user of the device during the identification of the first and second dielectric responses, and estimating the amount of at least one volatile substance inhaled by the user per puff using the identified state changes of the article and the recorded number of puffs. Such information may be useful in enabling the user to estimate the consumption of volatile substances by counting puffs during future use of the device. It may also be of interest to manufacturers of devices or aerosol-generating articles to know more about the real-world use of their products.

[0023] The method according to the present invention may be performed, for example, automatically by an aerosol generating device immediately after insertion of an aerosol generating article, or only when requested by the user.

[0024] According to further aspects of this disclosure, the aerosol generating device is A heating chamber configured to receive an aerosol-generating article, A first terminal and a second terminal, which are disposed in the heating chamber such that when an aerosol-generating article is received in the heating chamber, the first and second terminals respectively come into contact with different portions of the aerosol-generating article; a voltage source; and a controller configured to perform the aforementioned method when the aerosol-generating article is inserted into the heating chamber.

[0025] Each of the first terminal and the second terminal is substantially planar, and may have a length and a width measured within the plane of the terminals. The first and second terminals are disposed parallel to each other on opposite sides of the heating chamber, such that the aerosol-generating article can be received therebetween, and the first and second terminals are separated by a vertical distance that is shorter than the length and width of the terminals. The fact that each terminal has a width and a length does not mean that it must be rectangular. The length may be defined as the maximum dimension of the terminal measured in any direction parallel to the plane, and the width may be defined as the maximum dimension of the terminal measured in a direction perpendicular to the length and parallel to the plane. The length and width may be equal, for example in the case of a square or circular terminal.

[0026] This configuration allows the aerosol-generating device to have a card-like form, that is, a thickness substantially smaller than its width and length, and to be used with an aerosol-generating article that easily slides between the terminals. The terminals can extend over a large area of the aerosol-generating substrate such that the measurement of the dielectric response encompasses most of the substrate. The relatively large area and small separation of the terminals produce a large capacitance therebetween, resulting in a sensitive measurement of the dielectric response.

[0027] Unless the context clearly dictates otherwise, throughout this specification and the claims, terms such as "comprising", "including" and the like are to be interpreted in an inclusive sense, that is, in the sense of "including but not limited to", as opposed to an exclusive or exhaustive sense.

[0028] In this specification, terms such as “upper side” and “lower side” refer to the orientation of the device as shown in the illustrative drawings, and are not intended to limit the device according to the present invention to being manufactured, stored, transported, or used in any particular orientation. [Brief explanation of the drawing]

[0029] [Figure 1] This is a schematic cross-sectional view of an aerosol generation system comprising an aerosol generation device and an aerosol generation article positioned within the heating chamber of the aerosol generation device. [Figure 2] This is a schematic partial cross-sectional view of a first embodiment of an aerosol generating system in which the method according to the present invention may be carried out. [Figure 3] This is a schematic partial cross-sectional view of a second embodiment of an aerosol generating system in which the method according to the present invention may be carried out. [Figure 4] This is a schematic perspective view of a third embodiment of an aerosol generating system in which the method according to the present invention may be performed. [Modes for carrying out the invention]

[0030] Herein, embodiments of the present disclosure will be described with reference to the attached drawings, merely as examples.

[0031] Referring first to Figure 1, a schematic diagram shows one embodiment of the aerosol generating system 1. The aerosol generating system 1 comprises an aerosol generating device 10 and an aerosol generating article 100 for use with the device 10. The aerosol generating device 10 can have any shape that is sized to fit the components described in the various embodiments described herein and to be comfortably held by a user with one hand without assistance.

[0032] The first end 14 of the aerosol generating device 10, shown on the bottom side of Figure 1, will be described for convenience as the distal, bottom, base, or lower end of the aerosol generating device 10. The second end 16 of the aerosol generating device 10, shown on the top side of Figure 2, will be described as the proximal, top, or upper end of the aerosol generating device 10. During use, the user typically directs the aerosol generating device 10 so that the first end 14 is facing downward and / or distal to the user's mouth, and the second end 16 is facing upward and / or close to the user's mouth.

[0033] The aerosol generating device 10 includes a heating chamber 18. The heating chamber 18 defines an internal volume in the form of a cavity 20 having a substantially cylindrical cross-section for housing an aerosol generating article 100. The cavity 20 of the heating chamber 18 opens toward the second end 16 of the aerosol generating device 10. The heating chamber 18 includes a heater 19 for heating the aerosol generated and received within the cavity 20. The heater may take various forms, but its general position is shown by a dashed line in Figure 1. The heating chamber 18 has a longitudinal axis defining its longitudinal direction and is formed from a heat-resistant plastic material such as polyetheretherketone (PEEK). The aerosol generating device 10 further includes a power supply 22, which may be one or more batteries, for example, rechargeable, and a controller 24 that connects the power supply to the heater. The controller 24 may also be connected to a user interface 23 which includes an input unit such as a power button for receiving commands from the user, and / or an output unit such as an indicator light, display screen, or audible or vibration alarm for providing information to the user. The controller may also be interfaced with an antenna 25 for wireless communication with a remote device such as the user's smartphone, which can be used for input and output, and for relaying data between the aerosol generating device 10 and its manufacturer.

[0034] The heating chamber 18, and specifically the cavity 20, is arranged to receive a substantially cylindrical or rod-shaped aerosol generating article 100 of the corresponding shape. Typically, the aerosol generating article 100 comprises a pre-packaged aerosol generating substrate 102. The aerosol generating article 100 is a disposable and replaceable article (also known as a “consumable”), which may contain, for example, tobacco as the aerosol generating substrate 102. The aerosol generating article 100 has a proximal end 104 (or mouth end) and a distal end 106. The distal end 106 is inserted into the heating chamber 18 of the aerosol generating device 10 so that at least the aerosol generating substrate 102 is housed inside the heating chamber 18. The aerosol generating article 100 further comprises a mouthpiece segment 108 positioned downstream of the aerosol generating substrate 102. At least a portion of the mouthpiece segment 108 protrudes from the heating chamber 18 so that the proximal end 104 of the aerosol generating article 100 is accessible to the user's mouth. When the aerosol generating device 10 heats the aerosol generating article 100, heated vapor is released from the aerosol generating substrate 102. As the user inhales, drawing air toward the proximal end 104 of the aerosol generating article 100, the vapor cools and condenses as it passes through the mouthpiece segment 108, forming an aerosol with properties suitable for inhalation. The mouthpiece segment 108 may further include a filter (not shown) to remove particles or droplets larger than a certain size from the airflow.

[0035] The aerosol-generating substrate 102 and the mouthpiece segment 108 are arranged coaxially within a wrapper 110 (e.g., a paper wrapper) to hold the components in place and form a rod-shaped aerosol-generating article 100. The wrapper 110 typically does not cover the ends 104, 106 of the aerosol-generating article 100 so that air can flow through the aerosol-generating article 100 from the distal end 106 to the proximal end 104.

[0036] In the illustrated embodiment of the present invention, the heating chamber 18 includes a closing base 32. That is, the heating chamber 18 is cup-shaped. This ensures that the air drawn out from the opening first end 26 is guided through the aerosol generating substrate 102.

[0037] Figures 2 and 3 show exemplary embodiments of the present invention. They schematically show a heating chamber 18 in which an aerosol generating device 102 is housed in its cavity 20. The power supply 22 is not shown in Figures 2 and 3.

[0038] In the embodiment shown in Figure 2, an induction heater is provided to heat an aerosol-generating article received in the cavity 20. A helical induction coil 36 surrounds and is spaced apart from the cavity 20. Means for mounting the induction coil 36 are typically mounted on the outer wall of the heating chamber 18. A heating controller 38 controls the supply of power from the power supply 22 to the induction coil 36. Among the electronic components of the controller 38 is an inverter arranged to convert a DC current from the power supply 22 into an AC high-frequency current for the induction coil 36.

[0039] The susceptor 40 is located inside the cavity 20 of the heating chamber 18. Various configurations of the susceptor 40 are known but will not be described here. Typically, the susceptor 40 comprises one or more elements arranged around the inner wall of the heating chamber 18, which are in contact with or very close to the wrapper 110 of the aerosol generating article 100 received in the cavity 20. When the heating controller 38 supplies power to the heating coil 36 at an appropriate frequency, it generates an alternating magnetic field, which in turn induces an electric current flowing through the susceptor 40. The material and structure of the susceptor 40 are selected so that the eddy currents induced within the susceptor 40 dissipate the power as heat. The heat is transferred by conduction, convection, and / or radiation to the substrate 102 of the aerosol generating article 100, vaporizing the volatile substances within the substrate 102. The volatile substances are carried by the airflow drawn through the aerosol generating article to form an aerosol that can be inhaled by the user as described earlier.

[0040] According to the present invention, the aerosol generating device 10 shown in Figure 2 further comprises a first terminal 42 and a second terminal 44 disposed within the cavity 20 of a heating chamber 18 such that the first and second terminals 42 and 44 each contact different parts of the aerosol generating article 100. The first and second terminals 42 and 44 are connected to a voltage generator 46 that draws power from a power supply 22 and selectively applies an AC voltage between the first and second terminals 42 and 44 at one or more desired frequencies. The first and second terminals 42 and 44 are further connected to an admittance analyzer 48 that measures the current flowing between the first and second terminals 42 and 44 while the AC voltage is applied to them and uses the characteristics of the measured current to identify the admittance or dielectric response of the aerosol generating article 100. The dielectric response, in turn, provides information regarding the state or characteristics of the substrate 102, as described below.

[0041] The first terminal 42 and the second terminal 44 are preferably positioned to contact a portion of the aerosol-generating article 100 that is relatively widely spaced apart from each other. As a result, the current flowing between the first and second terminals 42 and 44 samples a considerable portion of the substrate 102. In the embodiment shown in Figure 2, the first terminal 42 is positioned adjacent to the wrapper 110 of the aerosol-generating article 100 near the proximal end of the substrate 102. The second terminal 44 is positioned adjacent to the substrate 102 at the distal end 106 of the aerosol-generating article 100. The second terminal 44 is preferably positioned at or near the distal end 106 of the aerosol-generating article 100 so as not to be in complete contact with the second terminal 44 when the aerosol-generating article 100 is not fully inserted into the cavity 20. This affects the admittance measured between the first and second terminals 42, 44, so that the incorrect insertion of the aerosol generating article 100 can be detected by the admittance analyzer 48. The aerosol generating device 10 can then emit a signal to warn the user of the incorrect insertion of the aerosol generating article 100. If the aerosol generating article 100 is not properly inserted, the heating controller 38 may prevent power from being supplied to the heating coil 36.

[0042] In the illustrated embodiment shown in Figure 2, the second terminal 44 is positioned adjacent to the wrapper 110 on the radial outer surface of the aerosol-generating article 100, similar to the first terminal 42. In an alternative embodiment of the present invention (not shown), the second terminal 44 may be positioned adjacent to the end face of the aerosol-generating article 100, at the end 32 of the heating chamber 18. This ensures that the article 100 does not come into contact with the second terminal 44 unless it is fully and precisely inserted into the heating chamber 18. On the other hand, this may interfere with the airflow from the cavity 20 into the article 100.

[0043] Figure 3 is substantially the same as Figure 2, and the same reference numerals are used for similar elements of the aerosol generating system. The main difference lies in the heating component of the aerosol generating device 10, which in this embodiment of the present invention includes a blade 50 extending proximal from the base 32 of the heating chamber 18. When the aerosol generating article 100 is inserted into the cavity 20 of the heating chamber 18, the blade 50 is embedded in the aerosol generating substrate 102 so that heat can be applied directly to the substrate 102 from the inside. Unlike the induction heating in Figure 2, in this embodiment the blade 50 is a resistance heating element with a direct electrical connection to the heating controller 38.

[0044] A further difference from the embodiment in Figure 2 is that the blade 50 also functions as a second terminal of a circuit for measuring the dielectric response of the aerosol generating article 100. As shown in Figure 2, the first terminal 42 is positioned in contact with the wrapper 110 of the aerosol generating article 100 such that when the voltage generator 46 generates an AC voltage, a current flows between the first terminal 42 and the blade 50, passing through only about half of the aerosol generating substrate 102. The first terminal 42 can be made to extend around part or all of the circumference of the aerosol generating article 100 in order for the measured current to sample a larger portion of the aerosol generating substrate 102.

[0045] Since the blade 50 functions as both a heating element and a second terminal, it is easier to configure the system to switch between heating mode and measurement mode, thereby preventing the blade 50 from being used to measure the dielectric response of the aerosol-generating article 100 while also supplying heat. However, measuring the dielectric response simultaneously with heating is technically feasible and, in some cases, beneficial.

[0046] The embodiment in Figure 3 further includes a temperature sensor 52 disposed adjacent to the aerosol-generating substrate 102 and used to measure the temperature of the substrate 102 when the dielectric response is to be determined. Since the admittance of the substrate 102 is partially dependent on its temperature, the temperature measured by the sensor 52 can be used as a correction factor in determining the dielectric response. This is particularly important when the dielectric response is to be determined while the heater is operating. The temperature sensor 52 may be, for example, a thermocouple, a thermistor, a resistance temperature detector (RTD), or any other suitable device for determining temperature.

[0047] Figures 2 and 3 are used to illustrate various possible features of the aerosol generating system 1 according to the present invention, but it goes without saying that the features are not limited to those used in the specific combinations shown in these figures. For example, the induction coil 36 in Figure 2 may be used with a susceptor embedded in the substrate 102 in the same manner as the blade 50 in Figure 3. Conversely, instead of the embedded blade 50 in Figure 3, the resistance heater may comprise a heating element that contacts only the outside of the aerosol generating article 100, such as the susceptor 40 shown in Figure 2. The present invention relates to measuring the dielectric response of the aerosol generating substrate 102 and is substantially independent of the means employed to heat the substrate 102. Figure 3 only shows that a resistance heating element in the form of a blade 50 can serve as a second terminal of a circuit for measuring the dielectric response, but it is equally possible that the second terminal is provided by a heating element that contacts only the outside of the aerosol generating article 100 and / or by a susceptor of an induction heater. There are several aerosol generating devices in which the substrate is heated by being sandwiched between two heater plates. In such an embodiment, the two heater plates can also function as the first and second terminals 42 and 44 of the present invention, respectively.

[0048] Although the heating controller 38, voltage generator 46, and admittance analyzer 48 are shown as separate components, they may share common elements. For example, at least all of their control functions may be performed by a common processor that functions as a general-purpose controller 24 for the aerosol generation system 1. If the system 1 is operated via a wireless interface with a remote device such as a smartphone, the admittance analyzer 48 may be used only to measure the characteristics of the current between the first and second terminals 42, 44, and at least a specific portion of the dielectric response may be performed on the remote device.

[0049] Figure 4 shows a third embodiment of the aerosol generating system according to the present invention. For clarity, the heating chamber itself is not shown in Figure 4. In this embodiment, the aerosol generating article 100 is in the form of a flat rectangle having a thickness (measured vertically in the drawing) much smaller than its width or length. As already mentioned, the aerosol generating article 100 is enclosed by a wrapper 110 and includes an aerosol generating substrate 102 at its distal end 106. Air channels 112 are formed within the substrate 102 and extend through the substrate from the distal end 106 to communicate with an airflow path that emerges at the proximal end 104 of the aerosol generating article 100. The drawing shows three air channels 112 formed on the upper surface of the substrate 102, but the number and location of the channels 112 may differ in other embodiments.

[0050] The shape of the aerosol-generating article 100 provides large, flat top and bottom surfaces 60, 62. A first terminal 42 and a second terminal 44, used to measure the dielectric response of the article 100, are mounted within the heating chamber (not shown) of the aerosol-generating device 10 so as to be adjacent to the top and bottom surfaces 60, 62 of the aerosol-generating article 100, respectively. The terminals 42, 44 are planar, and they are substantially equal in size and shape, facing each other in a capacitor configuration with the aerosol-generating substrate 102 as the dielectric between them. Although Figure 4 is not drawn to a constant scale, it shows that the terminals 42, 44 are separated by a distance significantly smaller than their length and width. Wires 64 connect the first and second terminals 42, 44 to a voltage source and admittance analyzer (not shown in Figure 4). As shown in the figure, the first and second terminals 42, 44 extend over a substantial proportion of the area of ​​the upper and lower surfaces, respectively, of the aerosol-generating substrate 102, thereby sampling a substantial proportion of the volume of the substrate 102 for dielectric response measurement. This configuration provides the possibility that the first and second terminals 42, 44 also function as heating elements for the substrate 102. Most simply, the terminals 42, 44 may be used at a specific time to heat the substrate 102, and at different times, for example, before and after a vaping session, to measure the dielectric response. However, with appropriate control electronics, it is possible to perform dielectric response measurement simultaneously with the use of terminals 42, 44 to heat the substrate 102.

[0051] The flattened form of the aerosol-generating article 100 shown in Figure 4 does not negate the arrangement of the first and second terminals 42 and 44 as in Figure 2, thereby allowing the terminals 42 and 44 to extend over a smaller area, with the first terminal 42 positioned adjacent to one of the surfaces 60 and 62 of the article 100 near the proximal end of the base material 102, and the second terminal 44 positioned adjacent to the other of the surfaces 60 and 62 of the article 100 near the distal end of the base material 102.

[0052] While exemplary embodiments have been described in the preceding paragraphs, it goes without saying that various modifications can be made to these embodiments without departing from the scope of the attached claims. Therefore, the breadth and scope of the claims should not be limited to the exemplary embodiments described above.

[0053] Unless otherwise stated herein or unless clearly inconsistent with the context, any combination of the features described above in all possible variations is encompassed by this disclosure.

Claims

1. A method for operating an aerosol generating device, wherein the aerosol generating device is A heating chamber (18) configured to receive an aerosol-generating article (100), A first terminal (42) and a second terminal (44) are provided, wherein when an aerosol generating article (100) is received into the heating chamber (18), the first and second terminals (42, 44) are arranged in the heating chamber (18) such that they each contact different parts of the aerosol generating article (100), and the device comprises: The said method, (a) Inserting the aerosol generating article (100) into the heating chamber (18), (b) The step of applying an AC voltage at the applied frequency between the first and second terminals (42, 44), (c) The step of measuring the characteristics of the current flowing between the first and second terminals (42, 44) while the AC voltage is applied, (d) Using the measured characteristics for the current, the step of determining the dielectric response of the aerosol generating article (100) at the applied frequency, Steps (b) and (c) are performed with different applied frequencies. Step (d) includes determining the dielectric response of the aerosol-generating article (100) using the measured characteristics for the current at the different frequencies, and the method further includes Steps (b) to (d) are performed after inserting the aerosol-generating article (100) into the heating chamber (18) to determine a first dielectric response. The steps include: applying heat to the aerosol generating article (100) in the heating chamber (18); The steps are repeated to identify a second dielectric response, A step of comparing the second dielectric response with the first dielectric response to identify a change in the state of the article (100), Furthermore, the steps include recording the number of puffs inhaled by the user of the device (10) during the specified period of the first and second dielectric responses, A step of estimating the amount of at least one volatile substance inhaled by the user for each puff, using the identified state change and the recorded number of puffs for the article (100); Methods that include...

2. The method according to claim 1, wherein the step of measuring the characteristics of the current includes measuring the amplitude of the current and measuring the phase shift between the voltage and the current.

3. The method according to claim 1, wherein the step of identifying the dielectric response includes identifying both the conductive component and the capacitance component of the dielectric response.

4. The method according to claim 1, wherein the applied frequency is in the range of 100 Hz to 1 MHz.

5. The method according to claim 1, wherein the applied frequency is in the range of 1 kHz to 100 kHz.

6. The method according to claim 1, further comprising the step of measuring the temperature of the aerosol generating article (100), wherein step (d) includes determining the dielectric response of the aerosol generating article (100) using the measured characteristics for the current and the measured temperature.

7. The method according to claim 1, further comprising the steps of: identifying the state of the aerosol generating article (100) using the identified dielectric response; and outputting a signal to indicate the state of the article, or controlling the aerosol generating device in a manner corresponding to the state of the article (100).

8. The method according to claim 7, wherein the identified state of the aerosol generating article (100) is that the article has been improperly inserted into the heating chamber (18).

9. The method according to claim 1, comprising the step of outputting a signal indicating the change in state of the article (100), or controlling the aerosol generating device (10) in a manner corresponding to the change in state of the article (100).

10. The method according to claim 9, wherein the change in state of the article (100) is the depletion of volatile substances within the article (100).

11. The method according to claim 10, further comprising the step of using the identified state changes for the article (100) to estimate the amount of the at least one volatile substance inhaled by the user of the device during the identification of the first and second dielectric responses.

12. Aerosol generating device (100), A heating chamber (18) configured to receive an aerosol-generating article (100), A first terminal (42) and a second terminal (44) are arranged in the heating chamber (18) such that when the aerosol generating article (100) is received into the heating chamber (18), the first and second terminals (42, 44) each contact different parts of the aerosol generating article (100), Voltage source (46) and A controller (24) configured to perform the method described in any one of claims 1 to 11 when an aerosol generating article (100) is inserted into the heating chamber (18), an aerosol generating device (100) comprising the above.

13. Each of the first terminal (42) and the second terminal (44) is substantially planar and has a length and width measured within the plane of the terminals (42, 44). The first and second terminals (42, 44) are arranged parallel to each other on both sides of the heating chamber (18) such that the aerosol generating article (100) can be received between them, and the first and second terminals (42, 44) are spaced apart by a vertical distance shorter than the length and width of the terminals (42, 44). The aerosol generating device according to claim 12.

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