EP4674295A1

EP4674295A1 - Aerosol generation system, control method, and non-transitory storage medium

Info

Publication number: EP4674295A1
Application number: EP23928514.1A
Authority: EP
Inventors: Manabu Yamada; Yasunobu Inoue; Ryo Tamura
Original assignee: Japan Tobacco Inc
Current assignee: Japan Tobacco Inc
Priority date: 2023-03-17
Filing date: 2023-03-17
Publication date: 2026-01-07
Also published as: CN120769712A; KR20250145658A; JPWO2024194929A1; WO2024194929A1

Abstract

Provided is a mechanism with which it is possible to further reduce the size of an inhalation device. An aerosol generation system comprising a power supply unit that accumulates and supplies electric power, an accommodation unit that accommodates a base material in which an aerosol source is contained, a heating unit that heats the base material accommodated in the accommodation unit using the electric power supplied from the power supply unit, and a control unit that controls the supply of power to the heating unit. The control unit determines the state of the accommodation unit on the basis of the speed of change in a parameter that corresponds to the temperature of the heating unit.

Description

TECHNICAL FIELD

The present disclosure relates to an aerosol-generating system, a control method, and a non-transitory recording medium.

BACKGROUND ART

Inhalation devices that generate substances to be inhaled by users, such as electronic cigarettes and nebulizers, are in widespread use. For example, an inhalation device employs an aerosol source for generating an aerosol, and a substrate including a flavor source or the like for imparting a flavor component to the generated aerosol, to generate an aerosol to which the flavor component has been imparted. The user can enjoy the flavor by inhaling the aerosol to which the flavor component has been imparted, generated by the inhalation device. The action by which the user inhales the aerosol will also be referred to below as "puffing" or a "puffing action".
Various technical developments are underway for the purpose of further improving the quality of a user experience when using such an inhalation device. PTL 1 below, for example, discloses technology for sensing insertion of a substrate into an inhalation device based on a change in capacitance detected by a capacitive sensor fitted in the inhalation device.

CITATION LIST

PATENT LITERATURE

PTL 1: JP 2017-510270 A

SUMMARY OF INVENTION

TECHNICAL PROBLEM

In the technology disclosed in PTL 1 above, however, the inhalation device is fitted with the capacitive sensor and is proportionately larger as a result.
Accordingly, the present disclosure takes account of the abovementioned problem, and the objective of the present disclosure lies in providing an arrangement enabling an inhalation device to be made even more compact.

SOLUTION TO PROBLEM

In order to solve the problem above, one aspect of the present invention provides an aerosol-generating system comprising: a power source unit for storing and supplying power; an accommodating portion for accommodating a substrate containing an aerosol source; a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion; and a control unit for controlling electrical supply to the heating unit, wherein the control unit determines a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.
The control unit may control operation of the heating unit based on a result of determining the state of the accommodating portion.
The control unit may continue heating by the heating unit if the rate of change of the parameter satisfies a first condition, and may stop heating by the heating unit if the rate of change of the parameter does not satisfy the first condition.
The control unit may determine the state of the accommodating portion based on the rate of change of the parameter during a period from a first time which has elapsed since the heating unit started heating to generate an aerosol until a second time has elapsed.
The control unit may maintain a duty ratio of a voltage, which is applied to the heating unit, at a predetermined value during a period from the heating unit starting heating to generate an aerosol until the parameter satisfies a second condition, and varies the duty ratio of the voltage applied to the heating unit when the parameter has satisfied the second condition, and the first time and the second time may be set to arrive before the second condition is satisfied.
The control unit may maintain the duty ratio of the voltage, which is applied to the heating unit, at a predetermined value during a period from the heating unit starting heating to generate an aerosol until the second time has elapsed.
The first time may be at least 1 second.
The control unit may determine the state of the accommodating portion based on a time-series transition of a parameter corresponding to a temperature of the heating unit, which is obtained by repeatedly applying a sensing pulse group including one first sensing pulse to the heating unit, and may start heating by the heating unit to generate an aerosol based on a result of the determination.
The aerosol-generating system may further comprise the substrate.
Furthermore, in order to solve the problem above, another aspect of the present invention provides a control method implemented by means of a computer for controlling an aerosol-generating system, wherein the aerosol-generating system comprises: a power source unit for storing and supplying power; an accommodating portion for accommodating a substrate containing an aerosol source; and a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion, and wherein the control method comprises controlling electrical supply to the heating unit, and controlling electrical supply to the heating unit comprises determining a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.
Furthermore, in order to solve the problem above, another aspect of the present invention provides a non-transitory recording medium storing a program executed by means of a computer for controlling an aerosol-generating system, wherein the aerosol-generating system comprises: a power source unit for storing and supplying power; an accommodating portion for accommodating a substrate containing an aerosol source; and a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion, and wherein
the program causes the computer to function as a control unit for controlling electrical supply to the heating unit, and the control unit determines a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, the present disclosure provides an arrangement enabling an inhalation device to be made even more compact.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a schematic diagram schematically showing a configuration example of an inhalation device.
Fig. 2 is a diagram to illustrate first processing implemented by an inhalation device according to an embodiment of the present disclosure.
Fig. 3 is a diagram to illustrate first processing implemented by the inhalation device according to the embodiment.
Fig. 4 is a graph schematically showing an example of a heating profile.
Fig. 5 is a diagram to illustrate electrical supply control based on the heating profile.
Fig. 6 is a diagram to illustrate experimental results relating to the inhalation device according to the embodiment.
Fig. 7 is a flowchart showing an example of a flow of processing implemented by the inhalation device according to the embodiment.
Fig. 8 is a diagram to illustrate second processing implemented by the inhalation device according to the embodiment.
Fig. 9 is a diagram to illustrate second processing implemented by the inhalation device according to the embodiment.
Fig. 10 is a diagram to illustrate experimental results relating to the inhalation device according to the embodiment.
Fig. 11 is a flowchart showing an example of a flow of second processing implemented by the inhalation device according to the embodiment.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present disclosure will be described in detail below with reference to the appended drawings. It should be noted that components having substantially the same functional configuration will be assigned the same reference numbers in the description and drawings to avoid giving a duplicate description.
In this description and the drawings, elements having substantially the same functional configuration may also be distinguished by using the same code followed by an index comprising different alphabetic or numeric characters. For example, a plurality of elements having substantially the same functional configuration are distinguished, as necessary, as devices 1A, 1B and 1C. However, if there is no need to specifically distinguish between each of the plurality of elements having substantially the same functional configuration, only the same reference sign is assigned. For example, devices 1A, 1B and 1C are also referred to simply as device 1 when there is no need to distinguish between devices 1A, 1B and 1C.

1. Configuration example of inhalation device

An inhalation device is a device for generating a substance to be inhaled by a user. Hereinafter, the substance generated by the inhalation device will be described as being an aerosol. Additionally, the substance generated by the inhalation device may be a gas.
Fig. 1 is a schematic diagram schematically showing a configuration example of an inhalation device. As shown in fig. 1, an inhalation device 100 according to this configuration example comprises: a power source unit 111, a sensor unit 112, a notification unit 113, a memory unit 114, a communication unit 115, a control unit 116, a heating unit 121, an accommodating portion 140, and a heat insulating portion 144.
The power source unit 111 stores electrical power. The power source unit 111 then supplies the electrical power to each component of the inhalation device 100 in accordance with control performed by the control unit 116. The power supply portion 111 may be configured by a rechargeable battery such as a lithium ion secondary battery, for example.
The sensor unit 112 acquires various types of information relating to the inhalation device 100. As an example, the sensor unit 112 is configured by a pressure sensor such as a capacitor microphone, a flow rate sensor or a temperature sensor, etc., and acquires values associated with inhalation by a user. As another example, the sensor unit 112 is configured by an input device, such as a button or switch, for accepting input of information from the user.
The notification unit 113 notifies the user of information. The notification unit 113 is configured by a light-emitting device which emits light, a display device which displays images, a sound output device which outputs sound, or a vibrating device which vibrates, etc., for example.
The memory unit 114 stores various types of information for the operation of the inhalation device 100. The memory portion 114 is configured by a non-volatile storage medium such as a flash memory, for example.
The communication unit 115 is a communication interface capable of performing communication conforming to any wired or wireless communication standard. Examples of communication standards that may be used include standards that employ Wi-Fi (registered trademark), Bluetooth (registered trademark), BLE (Bluetooth Low Energy) (registered trademark), NFC (Near-Field Communication), or LPWA (Low Power Wide Area), for example.
The control unit 116 functions as an arithmetic processing device and a control device, and controls overall operation within the inhalation device 100 in accordance with various programs. The control unit 116 is realized by a CPU (central processing unit) or an electronic circuit such as a microprocessor, for example.
The accommodating portion 140 has an internal space 141, and holds a stick-type substrate 150 while accommodating a portion of the stick-type substrate 150 in the internal space 141. The accommodating portion 140 has an opening 142 allowing the internal space 141 to communicate with the outside, and accommodates the stick-type substrate 150 which has been inserted into the internal space 141 from the opening 142. For example, the accommodating portion 140 is a cylindrical body comprising the opening 142 and a bottom portion 143 serving as a bottom surface, and defines the columnar internal space 141. An air flow passage for supplying air to the internal space 141 is connected to the accommodating portion 140. An air inflow hole, which is an inlet for air into the air flow path, is disposed in a side surface of the inhalation device 100, for example. An air outflow hole, which is an outlet for air from the air flow passage to the internal space 141, is disposed in the bottom portion 143, for example.
The stick-type substrate 150 comprises a substrate portion 151 and a mouthpiece portion 152. The substrate portion 151 contains an aerosol source. The aerosol source comprises a tobacco-derived or non-tobacco-derived flavor component. If the inhalation device 100 is a medical inhaler such as a nebulizer, the aerosol source may include a drug. The aerosol source may, for example, be a liquid such as water or a polyhydric alcohol, for example glycerol or propylene glycol, containing the tobacco-derived or non-tobacco-derived flavor component, or may be a solid including the tobacco-derived or non-tobacco-derived flavor component. In a state in which the stick-type substrate 150 is held in the accommodating portion 140, at least part of the substrate portion 151 is accommodated in the internal space 141, and at least a portion of the mouthpiece portion 152 protrudes from the opening 142. Then, when the user holds the mouthpiece portion 152 protruding from the opening 142 in their mouth and inhales, air flows into the internal space 141 via the air flow passage, which is not illustrated in the drawings, and reaches the inside of the user's mouth together with the aerosol generated from the substrate portion 151.
The heating unit 121 heats the aerosol source to atomize the aerosol source, thereby generating the aerosol. In the example shown in fig. 1, the heating unit 121 has a film-like form and is arranged so as to cover the outer circumference of the accommodating portion 140. Then, when the heating unit 121 generates heat, the substrate portion 151 of the stick-type substrate 150 is heated from the outer circumference and an aerosol is generated. The heating unit 121 generates heat when supplied with electricity from the power source unit 111. By way of example, electricity may be supplied when the sensor unit 112 detects that the user has started inhaling and/or that predetermined information has been input. The supply of electricity may then be stopped when the sensor unit 112 detects that the user has finished inhaling and/or that predetermined information has been input.
The heat insulating portion 144 prevents heat transfer from the heating unit 121 to other components. For example, the heat insulating portion 144 is configured from a vacuum heat insulating material or an aerogel heat insulating material, or the like.
A configuration example of the inhalation device 100 has been described above. The inhalation device 100 is, of course, not limited to the configuration described above, and may adopt various configurations, such as those illustrated below by way of example.
As one example, the heating unit 121 may have a blade-like form and may be arranged so as to protrude into the internal space 141 from the bottom portion 143 of the accommodating portion 140. In that case, the blade-like heating unit 121 is inserted into the substrate portion 151 of the stick-type substrate 150 and heats the substrate portion 151 of the stick-type substrate 150 from the inside. As another example, the heating unit 121 may be arranged so as to cover the bottom portion 143 of the accommodating portion 140. Furthermore, the heating unit 121 may be configured by a combination of two or more from among a first heating unit covering the outer circumference of the accommodating portion 140, a blade-like second heating unit, and a third heating unit covering the bottom portion 143 of the accommodating portion 140.
As another example, the accommodating portion 140 may comprise an opening/closing mechanism such as a hinge for opening/closing part of a casing that forms the internal space 141. By opening/closing the casing, the accommodating portion 140 may then receive and grip the stick-type substrate 150 that has been inserted into the internal space 141. In that case, the heating unit 121 may be provided on the part of the accommodating portion 140 gripping the stick-type substrate 150, and may heat the stick-type substrate 150 while pressing same.
A configuration example of the inhalation device 100 has been described above. The heating unit 121 generates an aerosol by heating the stick-type substrate 150 (more specifically, the aerosol source contained in the stick-type substrate 150) accommodated in the accommodating portion 140, by using the power supplied from the power source unit 111. The control unit 116 then controls electrical supply to the heating unit 121. The inhalation device 100 is an example of an aerosol-generating system for generating an aerosol. The combination of the inhalation device 100 and the stick-type substrate 150 may also be considered to be an aerosol-generating system.

2. Technical Features

2.1 Heating associated with sensing insertion

The control unit 116 determines the state of the accommodating portion 140 based on a parameter corresponding to the temperature of the heating unit 121. The parameter corresponding to the temperature of the heating unit 121 is assumed hereinafter to be the electrical resistance (also referred to below simply as the resistance) of the heating unit 121 (a heating resistive element constituting the heating unit 121, to be more precise). The control unit 116 acquires the resistance of the heating unit 121 by applying a voltage to the heating unit 121. It is assumed hereinafter that the resistance of the heating unit 121 rises as the temperature of the heating unit 121 rises, and that the resistance of the heating unit 121 falls as the temperature of the heating unit 121 falls. That is to say, resistance and temperature may be treated as interchangeable in the description below.
The control unit 116 implements first processing to start with. The first processing comprises acquiring the resistance of the heating unit 121 and determining the state of the accommodating portion 140 based on the acquired resistance of the heating unit 121. In the first processing, the control unit 116 especially determines whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
If it is determined in the first processing that the stick-type substrate 150 is inserted in the accommodating portion 140, the control unit 116 terminates the first processing then implements second processing. The second processing comprises heating the stick-type substrate 150 based on a heating profile. A heating profile is control information for generating an aerosol. The inhalation device 100 is capable of generating an aerosol by heating the stick-type substrate 150 based on the heating profile. The heating profile will be described in detail later.
Here, it is possible for there to be an incorrect determination in the first processing that the stick-type substrate 150 is inserted in the accommodating portion 140, despite the stick-type substrate 150 not being inserted in the accommodating portion 140. This kind of incorrect determination may arise when an article other than the stick-type substrate 150, such as a cotton swab for cleaning, is inserted in the accommodating portion 140, or when external air is blown into the accommodating portion 140. This is because the resistance of the heating unit 121 can also change in such cases, in the same way as when the stick-type substrate 150 is inserted in the accommodating portion 140.
The control unit 116 therefore acquires the resistance of the heating unit 121 during heating based on the heating profile, and determines the state of the accommodating portion 140 based on the acquired resistance of the heating unit 121. In particular, the control unit 116 determines whether or not the determination in the first processing that the stick-type substrate 150 is inserted in the accommodating portion 140 is an incorrect determination.
If it has been determined that the stick-type substrate 150 is inserted in the accommodating portion 140, that is, if the determination in the first processing is judged to be correct, the control unit 116 continues heating of the stick-type substrate 150 based on the heating profile. Meanwhile, if it has been determined that the stick-type substrate 150 is not inserted in the accommodating portion 140, that is, if the determination in the first processing is judged to be incorrect, the control unit 116 stops heating of the stick-type substrate 150 based on the heating profile.
By virtue of this configuration, it is possible to automatically start and continue heating of the stick-type substrate 150 when the stick-type substrate 150 is inserted in the accommodating portion 140. Meanwhile, heating can be stopped when there is nothing inserted in the accommodating portion 140 or when an article other than the stick-type substrate 150 is inserted. It is thus possible to improve usability in that heating is started without the user giving a separate instruction to start/stop heating if the stick-type substrate 150 is inserted in the accommodating portion 140, therefore allowing the user to inhale the aerosol.
By virtue of this configuration, it is also possible for the heating unit 121 for heating the stick-type substrate 150 to be utilized to sense insertion of the stick-type substrate 150. That is to say, there is no need for another sensor such as a capacitive sensor to be fitted in order to sense insertion of the stick-type substrate 150. This allows the inhalation device 100 to be made even more compact.
It should be noted that, in the first processing, the heating unit 121 may heat up as a result of a voltage being applied to the heating unit 121 in order to acquire the resistance of the heating unit 121. That is to say, the first processing may be understood as processing for heating the stick-type substrate 150. However, unless specifically stated otherwise, it will be assumed hereinafter that heating denotes heating based on the heating profile in the second processing.
The first processing and the second processing will be described in detail below.

(1) First processing

Fig. 2 and 3 are diagrams to illustrate the first processing implemented by the inhalation device 100 according to the embodiment. A graph 30 shown in fig. 2 shows an example of a time-series transition of the voltage applied to the heating unit 121 in the first processing. The vertical axis in the graph 30 denotes voltage and the units are volts. The horizontal axis in the graph 30 denotes time and the units are seconds. A graph 35 shown in fig. 3 shows an example of a time-series transition of resistance of the heating unit 121 when the voltage shown in fig. 2 is applied. The vertical axis in the graph 35 denotes resistance and the units are ohms. The horizontal axis in the graph 35 denotes time and the units are seconds. The graph 35 depicts a case in which the stick-type substrate 150 was inserted into the accommodating portion 140 at the timing indicated by the arrow 39, that is, 5 seconds after the start of the first processing.
As shown in fig. 2, the control unit 116 repeatedly applies a sensing pulse group 34 including one first sensing pulse 31 to the heating unit 121. A "pulse" as referred to here is a wave having a predetermined voltage. In particular, the first sensing pulse 31 is a pulse for raising the temperature of the heating unit 121 while acquiring the resistance of the heating unit 121. A period during which one sensing pulse group 34 is applied will also be referred to below as a sensing cycle. A period of the sensing cycle during which the first sensing pulse 31 is applied will also be referred to as a temperature-increase period. Meanwhile, a period of the sensing cycle during which the first sensing pulse 31 is not applied will also be referred to as a temperature-reduction period. In the example shown in fig. 2, the duration of the sensing cycle is 0.5 seconds, with the first 0.1 seconds of the sensing cycle being the temperature-increase period and the remaining 0.4 seconds being the temperature-reduction period.
As shown in fig. 3, a voltage is applied to the heating unit 121 in the temperature-increase period, so the temperature of the heating unit 121 rises and there is also an associated increase in the resistance of the heating unit 121. Meanwhile, application of the voltage to the heating unit 121 is paused in the temperature-reduction period, so the temperature of the heating unit 121 falls and there is also an associated reduction in the resistance of the heating unit 121. That is to say, the resistance of the heating unit 121 fluctuates up and down in one sensing cycle. As shown in fig. 3, the resistance of the heating unit 121 gradually rises while repeatedly moving up and down in the process of the sensing pulse group 34 being repeatedly applied. Here, the voltage and span of the first sensing pulse 31 are adjusted so that the resistance of the heating unit 121 gradually rises or is maintained at a constant value in the process of the sensing pulse group 34 being repeatedly applied.
The control unit 116 determines the state of the accommodating portion 140 based on a time-series transition of the resistance of the heating unit 121 obtained by repeatedly applying the sensing pulse group 34 to the heating unit 121. To be more specific, the control unit 116 determines that the stick-type substrate 150 is inserted in the accommodating portion 140 when the time-series transition of the resistance of the heating unit 121 satisfies a predetermined condition. Meanwhile, the control unit 116 determines that the stick-type substrate 150 is not inserted in the accommodating portion 140 when the time-series transition of the resistance of the heating unit 121 does not satisfy the predetermined condition.
The time-series transition of the resistance of the heating unit 121 in the period during which the sensing pulse group 34 is applied to the heating unit 121 varies according to whether or not the stick-type substrate 150 is inserted in the accommodating portion 140. In the example shown in fig. 3, the period until 5 seconds have elapsed from the start of the first processing is when the stick-type substrate 150 is not inserted in the accommodating portion 140. During that period, the resistance at the start of application of the first sensing pulse 31 is located on a line 37, and the resistance at the end of application of the first sensing pulse 31 is located on a line 38. Meanwhile, in the example shown in fig. 3, the period after 5 seconds have elapsed from the start of the first processing is when the stick-type substrate 150 is inserted in the accommodating portion 140. During that period, the resistance at the start of application of the first sensing pulse 31 is located below the line 37, and the resistance at the end of application of the first sensing pulse 31 is located below the line 38. The control unit 116 therefore determines that the stick-type substrate 150 is inserted in the accommodating portion 140 when a change such as illustrated in fig. 3 has occurred in the time-series transition of the resistance of the heating unit 121 during the process of repeatedly applying the sensing pulse group 34. This simple configuration makes it possible to determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
As shown in fig. 2, the first processing may comprise initially applying a third sensing pulse 33 to the heating unit 121. The third sensing pulse 33 is a pulse for raising the temperature of the heating unit 121 while acquiring the resistance of the heating unit 121. The duration of the third sensing pulse 33 is longer than the duration of the first sensing pulse 31. In the example shown in fig. 2, the duration of the first sensing pulse 31 is 0.1 seconds and the duration of the third sensing pulse 33 is 0.5 seconds. This configuration makes it possible to raise the resistance of the heating unit 121 to a certain extent immediately after the start of the first processing. If the resistance of the heating unit 121 is not increased to a certain extent, it is possible that the resistance of the heating unit 121 will not fall to a suitable extent in the temperature-reduction period of the sensing cycle. This configuration enables suitable increases and reductions in the resistance of the heating unit 121 in the sensing cycle and therefore makes it possible to determine the state of the accommodating portion with greater accuracy.
It should be noted that the sensing pulse group 34 may comprise one or more second sensing pulses in addition to the single first sensing pulse 31. The second sensing pulse is a pulse for acquiring the resistance of the heating unit 121. The duration of the second sensing pulse is shorter than the duration of the first sensing pulse 31. In particular, the duration of the second sensing pulse is preferably set at such an extremely short time that there is no change in the temperature of the heating unit 121 even if the second sensing pulse is applied to the heating unit 121. This allows the resistance of the heating unit 121 to be acquired while the temperature of the heating unit 121 is falling in the temperature-reduction period.
The resistance of the heating unit 121 acquired by means of the second sensing pulse may be utilized in order to determine the state of the accommodating portion 140. This configuration makes it possible to determine the state of the accommodating portion 140 based on a greater number of samples, and therefore makes it possible to suppress a reduction in the accuracy of determining the state of the accommodating portion 140 due to the effects of interference, for example.
The control unit 116 may be triggered to start the first processing after detecting a predetermined user operation. The predetermined user operation may be a user operation which would presumably lead to the stick-type substrate 150 being inserted into the accommodating portion 140 immediately after this predetermined user operation has been performed. An example of the predetermined user operation would be opening a cover for opening/closing the opening 142. Another example of the predetermined user operation would be lifting the inhalation device 100. Another example of the predetermined user operation would be stopping charging of the inhalation device 100. A sensor provided on the cover or a motion sensor, etc. may be used to detect whether or not these predetermined user operations have been performed. This configuration enables the first processing to be implemented only at a timing at which the stick-type substrate 150 could be inserted. It is therefore possible to restrict power consumption.
The control unit 116 terminates the first processing if the time-series transition of the resistance of the heating unit 121 does not satisfy a predetermined condition before a predetermined time has elapsed from the start of the first processing. In other words, the control unit 116 stops the first processing if it is not determined that the stick-type substrate 150 has been inserted into the accommodating portion 140 before the predetermined time has elapsed from the start of the first processing. The predetermined time should be set according to the time which it would normally be expected to take for the user to insert the stick-type substrate 150 after performing the predetermined user operation which triggers the start of the first processing, for example. In the example shown in fig. 2, the predetermined time is 10 seconds, and the sensing cycle is repeated a maximum of 18 times. This configuration makes it possible to restrict power consumption without adversely affecting usability.
Meanwhile, the control unit 116 starts the second processing when it is determined that the time-series transition of the resistance of the heating unit 121 has satisfied a predetermined condition in the first processing. In other words, the control unit 116 starts the second processing when it is determined in the first processing that the stick-type substrate 150 is inserted in the accommodating portion 140. This configuration makes it possible to improve usability in that there is no need for the user to give a separate instruction to start heating.

(2) Second processing

In the second processing, the control unit 116 controls operation of the heating unit 121 based on the heating profile and determines the state of the accommodating portion 140. These processing operations will be described in order below.

- Heating based on the heating profile

The control unit 116 controls the operation of the heating unit 121 based on the heating profile. The operation of the heating unit 121 is controlled by controlling electrical supply from the power source unit 111 to the heating unit 121. The heating unit 121 heats the stick-type substrate 150 using power supplied from the power source unit 111.
The heating profile is control information for controlling the temperature at which the aerosol source is heated. The heating profile defines a target value of a parameter corresponding to a temperature at which the aerosol source is heated. The temperature of the heating unit 121 is an example of the temperature at which the aerosol source is heated. A target value of the temperature of the heating unit 121 (also referred to below as the "target temperature") is an example of a target value of a parameter corresponding to the temperature at which the aerosol source is heated. The temperature of the heating unit 121 may be controlled to change in accordance with the time elapsed from the start of heating. In this case, the heating profile includes information defining a time-series transition of the target temperature. As another example, the heating profile may comprise a parameter (hereinafter also referred to as a power supply parameter) defining how power is supplied to the heating unit 121. The power supply parameters include, for example, a voltage applied to the heating unit 121, ON/OFF of the power supply to the heating unit 121, or a method of feedback control to be employed. ON/OFF of the power supply to the heating unit 121 may be considered as ON/OFF of the heating unit 121.
The control unit 116 controls the operation of the heating unit 121 such that the temperature of the heating unit 121 (also referred to below as the "actual temperature") transitions similarly to the target temperature defined in the heating profile. The heating profile is typically designed such that, when the user inhales the aerosol generated from the stick-type substrate 150, the flavor tasted by the user is optimized. The flavor tasted by the user can therefore be optimized by controlling operation of the heating unit 121 based on the heating profile.
The temperature control of the heating unit 121 can be realized by known feedback control, for example. The feedback control may be, for example, PID control (Proportional-Integral-Differential Controller). The control unit 116 may cause power from the power source unit 111 to be supplied to the heating unit 121 in the form of pulses by pulse width modulation (PWM) or pulse frequency modulation (PFM). In that case, the control unit 116 can control the temperature of the heating unit 121 by adjusting the duty ratio of the power pulses in the feedback control. Alternatively, the control unit 116 may perform simple on/off control in the feedback control. For example, the control unit 116 may perform heating by the heating unit 121 until the actual temperature reaches the target temperature, interrupt heating by the heating unit 121 when the actual temperature reaches the target temperature, and resume heating by the heating unit 121 when the actual temperature falls below the target temperature.
The temperature of the heating unit 121 can be quantified by measuring or estimating the electrical resistance value of the heating unit 121 (a heating resistive element constituting the heating unit 121, to be more precise), for example. This is because the electrical resistance value of the heating resistive element varies with temperature. The electrical resistance value of the heating resistive element can be estimated by measuring the amount of voltage drop at the heating resistive element, for example. The amount of voltage drop at the heating resistive element can be measured by a voltage sensor measuring a potential difference applied to the heating resistive element. In another example, the temperature of the heating unit 121 can be measured by a temperature sensor such as a thermistor installed near the heating unit 121.
The period from the start to the end of the process of generating an aerosol using the stick-type substrate 150 is also referred to hereinafter as a heating session. In other words, a heating session is a period of time during which electrical supply to the heating unit 121 is controlled on the basis of the heating profile. The beginning of the heating session is the timing at which heating based on the heating profile is started. The end of the heating session is the timing at which a sufficient amount of aerosol is no longer generated. The heating session comprises a first-half preheating period and a second-half puffing-possible period. The puffing-possible period is the period of time during which a sufficient amount of aerosol is expected to be generated. The preheating period is the period from when heating is started until the puffing-possible period is started. Heating performed in the preheating period is also referred to as preheating.
The notification unit 113 may notify the user of information indicative of the timing at which the preheating ends. For example, the notification unit 113 notifies the user of information announcing the end of the preheating period before the preheating period ends, or notifies the user of information indicating that the preheating has ended at the timing at which the preheating has ended. The notification to the user may be given by lighting an LED or by means of vibrations, for example. By referring to such notification, the user is able to take a puff immediately after the end of the preheating.
Similarly, the notification unit 113 may notify the user of information indicative of when the puffing-possible period ends. For example, the notification unit 113 notifies the user of information announcing the end of the puffing-possible period before the puffing-possible period ends, or notifies the user of information indicating that the puffing-possible period has ended at the timing at which the puffing-possible period has ended. The notification to the user may be given by lighting an LED or by means of vibrations, for example. By referring to such notification, the user is able to take puffs until the end of the puffing-possible period.
An example of the heating profile will be described with reference to fig. 4. Fig. 4 is a graph schematically showing an example of a heating profile. The horizontal axis of the graph 20 denotes time. The vertical axis of the graph 20 denotes temperature. The line 21 denotes a time-series transition of the target temperature. As shown in fig. 4, the heating session may include an initial temperature-increase period, an intermediate temperature-reduction period, and a temperature re-increase period in succession. The initial temperature-increase period is a period in which the temperature of the heating unit 121 rapidly rises after the start of heating and is kept at a high temperature. The intermediate temperature-reduction period is a period in which the temperature of the heating unit 121 drops after the initial temperature-increase period. The temperature re-increase period is a period in which the temperature of the heating unit 121 is once again increased after the intermediate temperature-reduction period. In the example shown in fig. 4, the target temperature rapidly increases to around 300°C during the initial temperature-increase period, then drops to around 230°C during the intermediate temperature-reduction period, after which the temperature increases stepwise to around 260°C during the temperature re-increase period. During the intermediate temperature-reduction period, electrical supply to the heating unit 121 may be interrupted and heating may be turned OFF. In the example shown in fig. 4, the period from the start of heating to partway through the initial temperature-increase period is the preheating period, and the period from part way through the initial temperature-increase period to the end of the temperature re-increase period is the puffing-possible period.
Electrical supply control based on the heating profile will be described next with reference to fig. 5. Fig. 5 is a diagram to illustrate electrical supply control based on the heating profile. A graph 40 shown in fig. 5 shows an example of a time-series transition of the voltage applied to the heating unit 121 during electrical supply control based on the heating profile. The vertical axis in the graph 40 denotes voltage and the units are volts. The horizontal axis in the graph 40 denotes time and the units are milliseconds.
As shown in fig. 5, the control unit 116 repeatedly applies a heating pulse group 44 including a measurement pulse 41 to the heating unit 121. The measurement pulse 41 is a pulse which is applied in order to measure the resistance of the heating unit 121. The heating pulse group 44 may comprise one or more heating pulses 42. The heating pulse 42 is a pulse which is applied in order to raise the temperature of the heating unit 121.
A period during which one heating pulse group 44 is applied will also be referred to below as a heating cycle. A period of the heating cycle during which the measurement pulse 41 is applied will also be referred to as a measurement period. Meanwhile, a period of the heating cycle during which the measurement pulse 41 is not applied will also be referred to as a non-measurement period. The heating pulse 42 may be applied in the non-measurement period. In the example shown in fig. 5, the duration of the heating cycle is 50 ms, with the first 3 ms of the heating cycle being the measurement period and the remaining 47 ms being the non-measurement period.
The control unit 116 controls the configuration of the heating pulse 42 in the non-measurement period. The configuration as referred to here means whether or not the heating pulse 42 is applied and the duration of the heating pulse 42. As shown in fig. 5, the duration of the heating pulse 42 may be set at any time of 47 ms or less. Furthermore, the number and start timing of heating pulses 42 in the non-measurement period may also be freely set.
In particular, the control unit 116 acquires the resistance of the heating unit 121 when the measurement pulse 41 is applied in the measurement period. The control unit 116 then controls the configuration of the heating pulse 42 in the non-measurement period belonging to the same heating cycle as the measurement period, based on the resistance of the heating unit 121 acquired in that measurement period and on the heating profile. At this time, the control unit 116 controls the duty ratio of the heating pulse 42 in the non-measurement period, based on the temperature of the heating unit 121 calculated from the resistance of the heating unit 121, and the target temperature defined in the heating profile.
It should be noted that the heating pulse group 44 described above is applied to the heating unit 121 during the initial temperature-increase period and the temperature re-increase period of the heating session. Meanwhile, the heating pulse group 44 need not be applied to the heating unit 121 during the intermediate temperature-reduction period of the heating session. In this case, a temperature sensor such as a thermistor which is provided separately may be used to determine whether or not the temperature of the heating unit 121 has fallen to the target temperature in the intermediate temperature-reduction period, or else this determination can be easily made on the basis of the time elapsed since electrical supply to the heating unit 121 was stopped.

- Determining the state of the accommodating portion 140

The control unit 116 determines the state of the accommodating portion 140 based on a time-series transition of the resistance of the heating unit 121 obtained by repeatedly applying the heating pulse group 44 to the heating unit 121. To be more specific, the control unit 116 determines that the stick-type substrate 150 is inserted in the accommodating portion 140 when the time-series transition of the resistance of the heating unit 121 satisfies a predetermined condition. Meanwhile, the control unit 116 determines that the stick-type substrate 150 is not inserted in the accommodating portion 140 when the time-series transition of the resistance of the heating unit 121 does not satisfy the predetermined condition.
The time-series transition of the resistance of the heating unit 121 in the period during which the heating pulse group 44 is applied to the heating unit 121 varies according to whether or not the stick-type substrate 150 is inserted in the accommodating portion 140. As an example, the resistance (i.e., the temperature) of the heating unit 121 rises more sharply when no stick-type substrate 150 is inserted in the accommodating portion 140 than when the stick-type substrate 150 is inserted in the accommodating portion 140. The control unit 116 therefore determines that the stick-type substrate 150 is inserted in the accommodating portion 140 when the time-series transition of the resistance of the heating unit 121 fits within a range of a time-series transition of the resistance of the heating unit 121 which would be expected when the stick-type substrate 150 is inserted. This simple configuration makes it possible to determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
It should be noted that the state of the accommodating portion 140 is preferably determined at the start of the preheating period of the heating session. This is to prevent empty heating or heating of an article other than the stick-type substrate 150 if insertion of the stick-type substrate 150 into the accommodating portion 140 has been incorrectly determined in the first processing.

(3) Experimental results

Experimental results from implementing the first processing and the second processing will be described with reference to fig. 6.
Fig. 6 is a diagram to illustrate experimental results relating to the inhalation device 100 according to the embodiment. A graph 50 shown in fig. 6 shows a time-series transition of the resistance of the heating unit 121 when the inhalation device 100 implemented the first processing and the second processing. The vertical axis in the graph 50 denotes resistance and the units are ohms. The horizontal axis in the graph 50 denotes time and the units are seconds. The resistance of the heating unit 121 measured at each time point is plotted on the graph 50, with lines joining successive plots in time. The graph 50 depicts the time-series transition of the resistance of the heating unit 121 when the stick-type substrate 150 was inserted at the timing indicated by the arrow 59, i.e., at the time when 4.5 seconds have elapsed from the start of the first processing.
Referring to the graph 50, the resistance of the heating unit 121 gradually rises while repeatedly moving up and down during the time until the stick-type substrate 150 is inserted. Immediately after the stick-type substrate 150 has been inserted, the resistance of the heating unit 121 falls from the plot 51A to the plot 51B and from the plot 52A to the plot 52B. It should be noted that the plots 51A and 51B correspond to the resistance of the heating unit 121 at the start of application of the first sensing pulse 31. The plots 52A and 52B correspond to the resistance of the heating unit 121 at the end of application of the first sensing pulse 31. The control unit 116 determines that the stick-type substrate 150 has been inserted into the accommodating portion 140 based on this drop in resistance of the heating unit 121. Consequently, the first processing is terminated and the second processing is started, and the resistance of the heating unit 121 rises sharply.

(4) Processing flow

The processing flow will be described next with reference to fig. 7.
Fig. 7 is a flowchart showing an example of the flow of processing implemented by the inhalation device 100 according to the embodiment.
As shown in fig. 7, the control unit 116 first of all determines whether or not the predetermined user operation has been detected (step S102). For example, the control unit 116 determines whether or not a user operation to open the cover for opening/closing the opening 142, a user operation to lift the inhalation device 100, or a user operation to stop charging of the inhalation device 100 has been detected by means of the sensor unit 112.
If it is determined that no predetermined user operation has been detected (step S102: NO), the control unit 116 stands by until the predetermined user operation is detected.
If it is determined that a predetermined user operation has been detected (step S102: YES), the control unit 116 starts the first processing (step S104). For example, the control unit 116 initially applies the third sensing pulse 33 to the heating unit 121 and then repeatedly applies the sensing pulse group 34 to the heating unit 121.
The control unit 116 then determines whether or not the stick-type substrate 150 has been inserted into the accommodating portion 140 (step S106). For example, the control unit 116 determines whether or not the stick-type substrate 150 has been inserted into the accommodating portion 140 based on whether or not the time-series transition of the resistance of the heating unit 121 obtained by repeatedly applying the sensing pulse group 34 to the heating unit 121 satisfies a predetermined condition.
If it is determined that the stick-type substrate 150 has been inserted into the accommodating portion 140 (step S106: YES), the control unit 116 terminates the first processing and starts the second processing (step S108). For example, the accommodating portion 140 repeatedly applies the heating pulse group 44 to the heating unit 121 based on the heating profile.
Meanwhile, if it is determined that the stick-type substrate 150 is not inserted in the accommodating portion 140 (step S106: NO), the control unit 116 determines whether or not a predetermined time has elapsed from the start of the first processing (step S110). For example, the control unit 116 determines whether or not 10 seconds have elapsed from the start of the first processing.
If it is determined that the predetermined time has not elapsed from the start of the first processing (step S110: NO), the processing returns to step S106.
Meanwhile, if it is determined that the predetermined time has elapsed from the start of the first processing (step S110: YES), the control unit 116 terminates the first processing (step S112). The processing ends after this.
After the second processing has been started in step S108, the control unit 116 determines whether or not the determination result in the first processing is correct (step S114). For example, the control unit 116 determines whether or not the stick-type substrate 150 has been inserted into the accommodating portion 140 based on whether or not the time-series transition of the resistance of the heating unit 121 obtained by repeatedly applying the heating pulse group 44 to the heating unit 121 satisfies a predetermined condition.
If it has been determined that the determination result in the first processing is correct, that is to say, if it has been determined that the stick-type substrate is inserted in the accommodating portion 140 (step S114: YES), the control unit 116 continues heating based on the heating profile (step S116). The processing ends when the heating based on the heating profile ends.
Meanwhile, if it has been determined that the determination result in the first processing is incorrect, that is to say, if it has been determined that the stick-type substrate is not inserted in the accommodating portion 140 (step S114: NO), the control unit 116 terminates heating based on the heating profile (step S118). The processing ends after this.
An example of the flow of processing implemented by means of the inhalation device 100 according to the embodiment was described above. The notification unit 113 may provide an appropriate notification of information indicating the progress of the processing above. For example, the notification unit 113 may provide notifications of the start of the first processing, the determination result in the first processing, the start of the second processing, and the determination result in the second processing.

2.2. Determination standard in second processing

(1) Determination standard

A detailed description will be given below of the determination standard used to determine the state of the accommodating portion 140 in the second processing. The determination standard is assumed to be set by means of the control unit 116.
In the second processing, the control unit 116 determines the state of the accommodating portion 140 based on a rate of change of a parameter corresponding to the temperature of the heating unit 121. That is to say, in the second processing, the control unit 116 determines whether or not the stick-type substrate 150 is inserted in the accommodating portion 140 on the basis of the rate of change of the resistance of the heating unit 121 during heating based on heating profile. Note that the rate of change of the resistance the heating unit 121 may be understood as an amount of change of the resistance of the heating unit 121 at a predetermined time. This simple configuration makes it possible to determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
The control unit 116 controls operation of the heating unit 121 based on the result of determining the state of the accommodating portion 140. To be more specific, the control unit 116 continues heating of the stick-type substrate 150 based on the heating profile when it has been determined that the stick-type substrate 150 is inserted in the accommodating portion 140. Meanwhile, the control unit 116 stops heating of the stick-type substrate 150 based on the heating profile when it has been determined that the stick-type substrate 150 is not inserted in the accommodating portion 140. This configuration makes it possible to improve usability in that there is no need for a separate instruction to continue/stop heating.
The control unit 116 may determine that the stick-type substrate 150 is inserted in the accommodating portion 140 if the rate of change of the resistance of the heating unit 121 satisfies a first condition. In that case the control unit 116 continues heating by the heating unit 121. Meanwhile, the control unit 116 may determine that the stick-type substrate 150 is not inserted in the accommodating portion 140 if the rate of change of the resistance of the heating unit 121 does not satisfy the first condition. In that case the control unit 116 stops heating by the heating unit 121.
The first condition may be that the rate of change of the resistance of the heating unit 121 is less than a predetermined threshold. This is because the rate of change of the resistance of the heating unit 121 tends to be lower when the stick-type substrate 150 is inserted in the accommodating portion 140 than when the stick-type substrate 150 is not inserted in the accommodating portion 140.
Here, heating by the heating unit 121 is sometimes performed continuously. For example, a user sometimes "chain smokes", which is where the stick-type substrate 150 is continuously heated while being replaced for the user to inhale the aerosol. The resistance (i.e., temperature) of the heating unit 121 at the start of heating based on the heating profile is higher with this kind of continuous heating than without such heating. Non-continuous heating, that is, heating which is started in a state where a long period of time has elapsed from the end of the previous heating so that the heating unit 121 has sufficiently cooled, will also be referred to below as "first heating". Meanwhile, continuous heating, that is, heating which is started in a state where a long period of time has not elapsed from the end of the previous heating so that the heating unit 121 is still warm, will also be referred to below as "second heating".
The first condition will be described below with reference to fig. 8.
Fig. 8 is a diagram to illustrate second processing implemented by the inhalation device 100 according to the embodiment. A graph 60 shown in fig. 8 shows experimental results from observations of the time-series transition of the resistance of the heating unit 121 from the start of heating based on the heating profile. The vertical axis in the graph 60 denotes resistance and the units are ohms. The horizontal axis in the graph 60 denotes time and the units are seconds. It should be noted that the time shown on the horizontal axis of the graph 60 indicates the elapsed time from the start of heating based on the heating profile. The elapsed time from the start of heating based on the heating profile will also be referred to below as the heating time.
A line 61 shows the time-series transition of the resistance of the heating unit 121 when the first heating was started with the stick-type substrate 150 inserted in the accommodating portion 140. A line 62 shows the time-series transition of the resistance of the heating unit 121 when the first heating was started with nothing inserted in the accommodating portion 140. A comparison of the lines 61 and 62 shows that the inclination of the line 61 is smaller than the inclination of the line 62 during a period of the heating time from 0 seconds to 1.5 seconds. Based on the first condition, it is therefore possible to appropriately determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
A line 63 shows the time-series transition of the resistance of the heating unit 121 when the second heating was started with the stick-type substrate 150 inserted in the accommodating portion 140. A line 64 shows the time-series transition of the resistance of the heating unit 121 when the second heating was started with nothing inserted in the accommodating portion 140. A comparison of the lines 63 and 64 shows that the inclination of the line 63 is smaller than the inclination of the line 64 during a period of the heating time from 0 seconds to 1.5 seconds. Based on the first condition, it is therefore possible to appropriately determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
For both the first heating and the second heating, the rate of change of the resistance of the heating unit 121 is thus slower when the stick-type substrate 150 is inserted in the accommodating portion 140 than when nothing is inserted in the accommodating portion 140. This makes it possible to appropriately determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140 according to the first condition described above, regardless of whether or not the heating is continuous.
Here, the control unit 116 may determine the state of the accommodating portion 140 based on the rate of change of the resistance of the heating unit 121 during a period from a first time which has elapsed since the heating unit 121 started heating to generate an aerosol until a second time has elapsed. That is to say, the control unit 116 may determine the state of the accommodating portion 140 based on the rate of change of the resistance of the heating unit 121 during a period from a first time which has elapsed since the start of heating based on the heating profile until a second time has elapsed. As an example, the first time may be 1 second and the second time may be 1.5 seconds. That is to say, the control unit 116 may determine the state of the accommodating portion 140 based on the rate of change of the resistance of the heating unit 121 during a period of the heating time from 1 second to 1.5 seconds. This configuration makes it possible to determine more appropriately whether or not the stick-type substrate 150 is inserted in the accommodating portion 140, as will be described in detail below.
Fig. 9 is a diagram to illustrate second processing implemented by the inhalation device 100 according to the embodiment. A graph 70 shown in fig. 9 shows experimental results from observations of the time-series transition of the resistance of the heating unit 121 from the start of heating based on the heating profile. The vertical axis in the graph 60 denotes resistance and the units are ohms. The horizontal axis in the graph 60 denotes time, more specifically heating time, and the units are seconds.
A line 71 shows the time-series transition of the resistance of the heating unit 121 when the first heating was started with the stick-type substrate 150 inserted in the accommodating portion 140. A line 72 shows the time-series transition of the resistance of the heating unit 121 when the first heating was started with a dry cotton swab inserted in the accommodating portion 140. A line 73 shows the time-series transition of the resistance of the heating unit 121 when the first heating was started with a wet cotton swab inserted in the accommodating portion 140. A dry cotton swab is a cotton swab for cleaning which has a cleaning component formed from absorbent cotton or the like disposed at an end portion thereof, with the cleaning component disposed at the end portion being in a dry state. A wet cotton swab is a cotton swab for cleaning, with the cleaning component disposed at the end portion being in a wet state from being dipped in a liquid such as an alcohol.
A comparison of the lines 71 and 72 shows that the line 71 has a smaller inclination than the line 72 during a period of the heating time from 0 seconds to 1.5 seconds. Based on the first condition, it is therefore possible to appropriately determine whether or not the stick-type substrate 150 is inserted in the accommodating portion 140.
Meanwhile, referring to the part of the line 73 contained in a range 79, the resistance of the heating unit 121 rises for a time and then falls. This is due to the heat of the heating unit 121 being lost as the wet part of the wet cotton swab dries. A wet cotton swab being inserted in the accommodating portion 140 thus produces a temporary drop in the resistance of the heating unit 121. A comparison of the lines 71 and 73 shows that, as a result, a period of the heating time between 0 seconds and 1 second includes a segment where the inclination of the line 73 is even smaller than the inclination of the line 71. This means that if the determination is based on the rate of change of the resistance of the heating unit 121 during a period of the heating time from 0 seconds to 1 second, there is a risk of an incorrect determination that the stick-type substrate 150 is inserted in the accommodating portion 140 even though a wet cotton swab is inserted.

Detailed experimental results from observations of the rate of change of the resistance of the heating unit 121 are shown here in Tables 1 and 2. In particular, Table 1 shows the rate of change of the resistance of the heating unit 121 during a period from 0 seconds to 1 second from the start of heating when the stick-type substrate 150, a dry cotton swab, or a wet cotton swab is inserted in the accommodating portion 140. Table 2 shows the rate of change of the resistance of the heating unit 121 during a period from 1 second to 1.5 seconds from the start of heating when the stick-type substrate 150, a dry cotton swab, or a wet cotton swab is inserted in the accommodating portion 140. Furthermore "1st" denotes the first heating. "2nd (4 minutes)" denotes a case in which the second heating is started after 4 minutes have elapsed from the end of the previous heating. "2nd (2 minutes)" denotes a case in which the second heating is started after 2 minutes have elapsed from the end of the previous heating. "2nd (1 minute)" denotes a case in which the second heating is started after 1 minute has elapsed from the end of the previous heating. "2nd (30 seconds)" denotes a case in which the second heating is started after 30 seconds have elapsed from the end of the previous heating.

TABLE 1

Table 1. Rate of change of resistance of heating unit 121 during period from 0 seconds to 1 second from start of heating [mΩ]
Inserted article	1st	2nd (4 minutes)	2nd (2 minutes)	2nd (1 minute)	2nd (30 seconds)
Stick-type substrate 150	79.6	84.5	85.3	72.8	65.3
Dry cotton swab	105	101	100	93.6	94.2
Wet cotton swab	86.4	92.8	87.3	67.1	33.6

TABLE 2

Table 2. Rate of change of resistance of heating unit 121 during period from 1 second to 1.5 seconds from start of heating [mΩ]
Inserted article	1st	2nd (4 minutes)	2nd (2 minutes)	2nd (1 minute)	2nd (30 seconds)
Stick-type substrate 150	38.8	42.8	44.0	37.0	34.4
Drv cotton swab	75.6	61.4	58.6	56.2	60.2
Wet cotton swab	56.6	53.0	55.2	71.4	65.6

Referring to Table 1, it can be seen that when the inserted article is the stick-type substrate 150, the resistance of the heating unit 121 has a lower rate of change in all cases than when the inserted article is a dry cotton swab. That is to say, in the period from 0 seconds to 1 second from the start of heating, a determination based on the first condition makes it possible to appropriately determine that the stick-type substrate 150 is not inserted when a dry cotton swab is inserted in the accommodating portion 140.
Meanwhile, referring to Table 1, it can be seen that there are cases where the rate of change of the resistance of the heating unit 121 when the inserted article is the stick-type substrate 150 is faster than the rate of change of the resistance of the heating unit 121 when the inserted article is a wet cotton swab. That is to say, if a determination based on the first condition is made in the period from 0 seconds to 1 second from the start of heating, there is a risk of an incorrect determination that the stick-type substrate 150 is inserted, despite the fact that a wet cotton swab is inserted in the accommodating portion 140.
Referring to Table 2, it can be seen that when the inserted article is the stick-type substrate 150, the resistance of the heating unit 121 has a lower rate of change in all cases than when the inserted article is a dry cotton swab or a wet cotton swab. That is to say, in the period from 1 second to 1.5 seconds from the start of heating, a determination based on the first condition makes it possible to appropriately determine that the stick-type substrate 150 is not inserted, whether a wet cotton swab or a dry cotton swab is inserted in the accommodating portion 140. In this way, even if the inserted article contains a liquid such as an alcohol or moisture from the atmosphere, for example, it is possible to improve determination accuracy by making a determination based on the first condition in a period after a predetermined time, preferably 1 second or more, has elapsed from the start of heating, so as to take account of the period during which this liquid evaporates.
For example, the control unit 116 may determine that the stick-type substrate 150 is inserted in the accommodating portion 140 if the rate of change of the resistance of the heating unit 121 during a period of the heating time from 1 second to 1.5 seconds is less than 50 [mΩ/s]. This will make it possible to determine that the stick-type substrate 150 is inserted in the accommodating portion 140 when the inserted article is the stick-type substrate 150 in all of the cases shown in Table 2. Meanwhile, the control unit 116 may determine that the stick-type substrate 150 is not inserted in the accommodating portion 140 if the rate of change of the resistance of the heating unit 121 during a period of the heating time from 1 second to 1.5 seconds is equal to or greater than 50 [mΩ/s]. This will make it possible to determine that the stick-type substrate 150 is not inserted in the accommodating portion 140 when the inserted article is a dry cotton swab or a wet cotton swab in all of the cases shown in Table 2.
Here, the control unit 116 maintains the duty ratio of the voltage, which is applied to the heating unit 121, at a predetermined value during a period from the heating unit 121 starting heating to generate an aerosol until the resistance of the heating unit 121 satisfies a second condition. For example, the control unit 116 maintains the duty ratio of the voltage, which is applied to the heating unit 121, at 100% during the period from the start of heating based on the heating profile until the resistance of the heating unit 121 reaches 99.8% of the resistance which corresponds to the maximum target temperature. This is because, immediately after the start of heating, there is a large temperature difference between the actual temperature of the heating unit 121 and the target temperature (e.g., 300°C). This makes it possible to minimize the length of the preheating period. The maximum target temperature as referred to here may be the maximum target temperature among target temperatures defined in the heating profile, and may especially be the maximum target temperature in the preheating period.
When the resistance of the heating unit 121 has satisfied the second condition, the control unit 116 then varies the duty ratio of the voltage applied to the heating unit 121. For example, the control unit 116 reduces the duty ratio of the voltage, which is applied to the heating unit 121, to less than 100% when the resistance of the heating unit 121 has reached 99.8% of the resistance which corresponds to the maximum target temperature. This makes it possible to prevent a situation where the temperature of the heating unit 121 exceeds the maximum target temperature.
The first time and the second time are preferably set to be satisfied before the second condition is satisfied. By virtue of this configuration, it is determined whether or not the first condition is satisfied during the period in which the duty ratio is fixed at 100%. It is therefore possible to exclude the effect of a change in the duty ratio from the determination of whether or not the first condition is satisfied, so the state of the accommodating portion 140 can be determined with greater accuracy. It should be noted that the second condition may be specified from a coefficient in PID control.
More simply, the control unit 116 may maintain the duty ratio of the voltage, which is applied to the heating unit 121, at a predetermined value during a period from the heating unit 121 starting heating to generate an aerosol until the second time has elapsed. For example, the control unit 116 may maintain the duty ratio at 100% until the heating time passes the second time and the resistance of the heating unit 121 subsequently satisfies the second condition, and thereafter reduce the duty ratio to less than 100%. This configuration makes it possible to determine the state of the accommodating portion 140 with greater accuracy, as described above.

(2) Comparison with comparative example

The determination standard according to the embodiment mentioned above will be described below while also describing a comparative example in relation to the determination standard according to the embodiment.
As a determination standard according to the comparative example, it is feasible to determine the state of the accommodating portion 140 based on the heating time at a timing when the resistance of the heating unit 121 has satisfied a predetermined condition. For example, it is feasible to determine that the stick-type substrate 150 is inserted in the accommodating portion 140 when the heating time at a timing when the resistance of the heating unit 121 has reached 99.5% of a resistance which corresponds to the maximum target temperature is longer than a predetermined threshold. This is because the rate of change of the resistance of the heating unit 121 tends to be lower, that is, the heating time taken until the resistance of the heating unit 121 rises tends to be longer, when the stick-type substrate 150 is inserted in the accommodating portion 140 than when the stick-type substrate 150 is not inserted in the accommodating portion 140.
With the determination standard according to such a comparative example, however, there is a risk of a drop in determination accuracy during the second heating as compared to the determination standard according to the embodiment described above. In other words, the determination standard according to the embodiment is capable of maintaining higher detection accuracy, even during the second heating, as compared to the determination standard according to the comparative example. This will be described in detail with reference to Table 3.

Table 3 below shows detailed experimental results from observations of the heating time when the resistance of the heating unit 121 reaches 99.5% of a resistance which corresponds to the maximum target temperature. In particular, Table 3 shows experimental results for the same cases as in Tables 1 and 2 when the stick-type substrate 150, a dry cotton swab, or a wet cotton swab is inserted in the accommodating portion 140.

TABLE 3

Table 3. Heating time when resistance of heating unit 121 reaches 99.5% of resistance corresponding to maximum target temperature [s]
Inserted article	1st	2nd (4 minutes)	2nd (2 minutes)	2nd (1 minute)	2nd (30 seconds)
Stick-type substrate 150	6.0	5.4	4.7	3.9	3.2
Dry cotton swab	3.2	2.9	2.5	2.2	1.7
Wet cotton swab	3.8	3.5	3.1	2.8	2.9

Referring to Table 3, there is a difference of 1.1 seconds or greater between when the inserted article is the stick-type substrate 150 and when the inserted article is a dry cotton swab or a wet cotton swab for the first heating and for the second heating started when the elapsed time from the end of the previous heating is 4 minutes, 2 minutes, or 1 minute. Meanwhile, there is a slight difference of 0.3 seconds between when the inserted article is the stick-type substrate 150 and when the inserted article is a wet cotton swab for the second heating started when the elapsed time from the end of the previous heating is 30 seconds. Considering that there may only be such a slight difference, there is a possibility of an incorrect determination with the determination standard according to the comparative example.
As described above, with the determination standard according to the comparative example, there is a risk of a drop in determination accuracy for the second heating started when the elapsed time from the end of the previous heating is 30 seconds. In contrast to this, and as described with reference to Tables 1 and 2, a determination based on the first condition makes it possible to appropriately determine, in all cases, whether or not the stick-type substrate 150 is inserted.

(3) Experimental results

The results of experiments using the inhalation device 100 adopting the determination standard above will be described with reference to fig. 10.
Fig. 10 is a diagram to illustrate experimental results relating to the inhalation device 100 according to the embodiment. A graph 80 shown in fig. 10 shows a time-series transition of the resistance of the heating unit 121 when the inhalation device 100 implemented the first processing and the second processing. The vertical axis in the graph 80 denotes resistance and the units are ohms. The horizontal axis in the graph 80 denotes time and the units are seconds. In this experiment, the state of the accommodating portion 140 is determined based on the rate of change of the resistance of the heating unit 121 during a period of the heating time (the elapsed time from the start of heating based on the heating profile) from 1 second to 1.5 seconds.
A line 81 depicts the time-series transition of the resistance of the heating unit 121 when the stick-type substrate 150 was inserted at the timing indicated by the arrow 88, i.e., at the time when 3.7 seconds have elapsed from the start of the first processing, and the first heating based on the heating profile has been started. On the line 81, the span of the increase in resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is less than 25 [mΩ] (i.e., the rate of change is less than 50 [mΩ/s]). It is therefore determined that the stick-type substrate 150 is inserted in the accommodating portion 140, and heating based on the heating profile is continued.
A line 82 depicts the time-series transition of the resistance of the heating unit 121 when the stick-type substrate 150 was incorrectly judged to have been inserted, despite nothing being inserted in the accommodating portion 140, at the timing indicated by the arrow 89, i.e., at the time when 3.2 seconds have elapsed from the start of the first processing, and the first heating based on the heating profile has been started.
On the line 82, the span of the increase in resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is equal to or greater than 25 [mΩ] (i.e., the rate of change is equal to or greater than 50 [mΩ/s]). It is therefore determined that the stick-type substrate 150 is not inserted in the accommodating portion 140, and heating based on the heating profile is stopped.
A line 83 depicts the time-series transition of the resistance of the heating unit 121 when the stick-type substrate 150 was inserted at the timing indicated by the arrow 88, i.e., at the time when 3.7 seconds have elapsed from the start of the first processing, and the second heating based on the heating profile has been started. On the line 83, the span of the increase in resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is less than 25 [mΩ] (i.e., the rate of change is less than 50 [mΩ/s]). It is therefore determined that the stick-type substrate 150 is inserted in the accommodating portion 140, and heating based on the heating profile is continued.
A line 84 depicts the time-series transition of the resistance of the heating unit 121 when the stick-type substrate 150 was incorrectly judged to have been inserted, despite nothing being inserted in the accommodating portion 140, at the timing indicated by the arrow 89, i.e., at the time when 3.2 seconds have elapsed from the start of the first processing, and the second heating based on the heating profile has been started. On the line 84, the span of the increase in resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is equal to or greater than 25 [mΩ] (i.e., the rate of change is equal to or greater than 50 [mQ/s]). It is therefore determined that the stick-type substrate 150 is not inserted in the accommodating portion 140, and heating based on the heating profile is stopped.

(4) Processing flow

The processing flow will be described next with reference to fig. 11.
Fig. 11 is a flowchart showing an example of the flow of second processing implemented by the inhalation device 100 according to the embodiment.
As shown in fig. 11, the control unit 116 first of all starts heating based on the heating profile (step S202).
The control unit 116 then determines whether or not the rate of change of the resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is less than 50 [mΩ/s].
If it is determined that the rate of change of the resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is less than 50 [mΩ/s] (step S104: YES), then the control unit 116 continues heating based on the heating profile (step S208). The processing ends after this, when heating based on the heating profile has ended.
Meanwhile, if it is determined that the rate of change of the resistance of the heating unit 121 during the period between 1 second and 1.5 seconds from the start of heating based on the heating profile is equal to or greater than 50 [mΩ/s] (step S104: NO), then the control unit 116 stops heating based on the heating profile (step S208). The processing ends after this.

3. Supplementary information

Preferred embodiments of the present disclosure were described in detail above with reference to the appended drawings, but the present disclosure is not limited to those examples. It is obvious that a person having ordinary knowledge in the technical field to which the present disclosure belongs will be able to conceive of a number of variant examples or modified examples within the scope of the technical concept disclosed in the claims, and any such variant examples or modified examples are naturally understood to fall within the technical scope of the present disclosure.
In the example described above, the state of the accommodating portion 140 is determined based on the resistance of the heating unit 121 in the first processing, but the present disclosure is not limited to this example. For example, the state of the accommodating portion 140, that is, whether or not the stick-type substrate 150 is inserted in the accommodating portion 140, may be sensed in the first processing by means of a capacitive sensor, a pressure sensor, an optical sensor, or a magnetic sensor, etc. Alternatively, the first processing may be omitted, and the second processing may be started based on a user operation such as pressing a button.
In the example described above, the resistance of the heating unit 121 rises as the temperature of the heating unit 121 rises, and the resistance of the heating unit 121 falls as the temperature of the heating unit 121 falls, but the present disclosure is not limited to this example. It is equally possible for the resistance of the heating unit 121 to fall as the temperature of the heating unit 121 rises, and for the resistance of the heating unit 121 to rise as the temperature of the heating unit 121 falls.
In the example described above, the parameter corresponding to the temperature of the heating unit 121 which is used in order to determine the state of the accommodating portion 140 is the resistance of the heating unit 121, but the present disclosure is not limited to this example. The parameter corresponding to the temperature of the heating unit 121 which is used in order to determine the state of the accommodating portion 140 may be the temperature of the heating unit 121 calculated on the basis of the resistance of the heating unit 121.
The embodiment above described an example in which a parameter relating to the temperature at which the aerosol source is heated, as defined in the heating profile, is a target value of the temperature of the heating unit 121, but the present disclosure is not limited to such an example. The heating profile may also define a target value of the resistance of the heating unit 121.
It should be noted that the series of processes performed by each device described in the present description may be realized by using software, hardware, or any combination of software and hardware. Programs constituting the software are prestored on a recording medium (more specifically, a non-transitory computer-readable storage medium) provided internally or externally to each device, for example. When the programs are then executed, for example, by a computer for controlling each device described in the present description, the programs are read into a RAM and executed by means of a processing circuit such as a CPU. The recording medium is, for example, a magnetic disk, an optical disk, a magneto-optical disk, or a flash memory, etc. Furthermore, the computer programs may be distributed via a network, for example, without the use of a recording medium. Furthermore, the computer may be an application-specific integrated circuit such as ASIC, a general-purpose processor which executes functions by reading software programs, or a computer on a server used for cloud computing, etc. Furthermore, the series of processes performed by each device described in the present description may be processed in a distributed manner by multiple computers.
Furthermore, the processing described using flowcharts and sequence diagrams in the present description need not necessarily be implemented in the order depicted. Some processing steps may be implemented in parallel. Furthermore, additional processing steps may be employed and some processing steps may be omitted.
The following configurations also fall within the technical scope of the present disclosure.

(1) An aerosol-generating system comprising: a power source unit for storing and supplying power;
- an accommodating portion for accommodating a substrate containing an aerosol source;
- a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion; and
- a control unit for controlling electrical supply to the heating unit,
- wherein
- the control unit determines a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.
(2) The aerosol-generating system as disclosed in (1) above, wherein the control unit controls operation of the heating unit based on a result of determining the state of the accommodating portion.
(3) The aerosol-generating system as disclosed in (2) above, wherein the control unit continues heating by the heating unit if the rate of change of the parameter satisfies a first condition, and stops heating by the heating unit if the rate of change of the parameter does not satisfy the first condition.
(4) The aerosol-generating system as disclosed in any one of (1) to (3) above, wherein the control unit determines the state of the accommodating portion based on the rate of change of the parameter during a period from a first time which has elapsed since the heating unit started heating to generate an aerosol until a second time has elapsed.
(5) The aerosol-generating system as disclosed in (4) above, wherein the control unit maintains a duty ratio of a voltage, which is applied to the heating unit, at a predetermined value during a period from the heating unit starting heating to generate an aerosol until the parameter satisfies a second condition, and varies the duty ratio of the voltage applied to the heating unit when the parameter has satisfied the second condition, and
the first time and the second time are set to arrive before the second condition is satisfied.
(6) The aerosol-generating system as disclosed in (5) above, wherein the control unit maintains the duty ratio of the voltage, which is applied to the heating unit, at a predetermined value during a period from the heating unit starting heating to generate an aerosol until the second time has elapsed.
(7) The aerosol-generating system as disclosed in any one of (4) to (6) above, wherein the first time is at least 1 second.
(8) The aerosol-generating system as disclosed in any one of (1) to (7) above, wherein the control unit determines the state of the accommodating portion based on a time-series transition of a parameter corresponding to a temperature of the heating unit, which is obtained by repeatedly applying a sensing pulse group including one first sensing pulse to the heating unit, and starts heating by the heating unit to generate an aerosol based on a result of the determination.
(9) The aerosol-generating system as disclosed in any one of (1) to (8) above, further comprising the substrate.
(10) A control method implemented by means of a computer for controlling an aerosol-generating system, wherein the aerosol-generating system comprises:
- a power source unit for storing and supplying power;
- an accommodating portion for accommodating a substrate containing an aerosol source; and
- a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion,
- and wherein
- the control method comprises
- controlling electrical supply to the heating unit, and
- controlling electrical supply to the heating unit comprises determining a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.
(11) A non-transitory recording medium storing a program executed by means of a computer for controlling an aerosol-generating system, wherein
the aerosol-generating system comprises:
- a power source unit for storing and supplying power;
- an accommodating portion for accommodating a substrate containing an aerosol source; and
- a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion,
- and wherein
- the program causes the computer to function as a control unit for controlling electrical supply to the heating unit, and the control unit determines a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.

REFERENCE SIGNS LIST

100 Inhalation device
111 Power source unit
112 Sensor unit
113 Notification unit
114 Memory unit
115 Communication unit
116 Control unit
121 Heating unit
140 Accommodating portion
141 Internal space
142 Opening
143 Bottom portion
150 Stick-type substrate
151 Substrate portion
152 Mouthpiece portion
31 First sensing pulse
33 Third sensing pulse
34 Sensing pulse group
41 Measurement pulse
42 Heating pulse
44 Heating pulse group

Claims

An aerosol-generating system comprising: a power source unit for storing and supplying power;
an accommodating portion for accommodating a substrate containing an aerosol source;

a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion; and

a control unit for controlling electrical supply to the heating unit,

wherein

the control unit determines a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.
The aerosol-generating system as claimed in claim 1, wherein the control unit controls operation of the heating unit based on a result of determining the state of the accommodating portion.
The aerosol-generating system as claimed in claim 2, wherein the control unit continues heating by the heating unit if the rate of change of the parameter satisfies a first condition, and stops heating by the heating unit if the rate of change of the parameter does not satisfy the first condition.
The aerosol-generating system as claimed in any one of claims 1 to 3, wherein the control unit determines the state of the accommodating portion based on the rate of change of the parameter during a period from a first time which has elapsed since the heating unit started heating to generate an aerosol until a second time has elapsed.
The aerosol-generating system as claimed in claim 4, wherein the control unit maintains a duty ratio of a voltage, which is applied to the heating unit, at a predetermined value during a period from the heating unit starting heating to generate an aerosol until the parameter satisfies a second condition, and varies the duty ratio of the voltage applied to the heating unit when the parameter has satisfied the second condition, and
the first time and the second time are set to arrive before the second condition is satisfied.
The aerosol-generating system as claimed in claim 5, wherein the control unit maintains the duty ratio of the voltage, which is applied to the heating unit, at a predetermined value during a period from the heating unit starting heating to generate an aerosol until the second time has elapsed.
The aerosol-generating system as claimed in any one of claims 4 to 6, wherein the first time is at least 1 second.
The aerosol-generating system as claimed in any one of claims 1 to 7, wherein the control unit determines the state of the accommodating portion based on a time-series transition of a parameter corresponding to a temperature of the heating unit, which is obtained by repeatedly applying a sensing pulse group including one first sensing pulse to the heating unit, and starts heating by the heating unit to generate an aerosol based on a result of the determination.
The aerosol-generating system as claimed in any one of claims 1 to 8, further comprising the substrate.
A control method implemented by means of a computer for controlling an aerosol-generating system, wherein
the aerosol-generating system comprises:
a power source unit for storing and supplying power;

an accommodating portion for accommodating a substrate containing an aerosol source; and

a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion,

and wherein

the control method comprises

controlling electrical supply to the heating unit, and

controlling electrical supply to the heating unit comprises determining a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.
A non-transitory recording medium storing a program executed by means of a computer for controlling an aerosol-generating system, wherein
the aerosol-generating system comprises:
a power source unit for storing and supplying power;

an accommodating portion for accommodating a substrate containing an aerosol source; and

a heating unit which uses power supplied from the power source unit to heat the substrate accommodated in the accommodating portion,

and wherein

the program causes the computer to function as a control unit for controlling electrical supply to the heating unit, and the control unit determines a state of the accommodating portion based on a rate of change of a parameter corresponding to a temperature of the heating unit.