EP4684668A1

EP4684668A1 - Aerosol generation system, control method, and program

Info

Publication number: EP4684668A1
Application number: EP23938470.4A
Authority: EP
Inventors: Takuya Iwamoto; Takeshi Akiyama; Manabu Yamada
Original assignee: Japan Tobacco Inc
Current assignee: Japan Tobacco Inc
Priority date: 2023-05-23
Filing date: 2023-05-23
Publication date: 2026-01-28
Also published as: CN121218899A; KR20250167643A; TW202446275A; JPWO2024241505A1; WO2024241505A1

Abstract

PROBLEM: To provide an arrangement capable of further improving the quality of a user experience.

SOLUTION: An aerosol-generating system comprising: a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; a heating unit for heating the substrate through the heat transfer portion; and a control unit for controlling operation of the heating unit, wherein the control unit controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.

Description

TECHNICAL FIELD

The present disclosure relates to an aerosol-generating system, a control method, and a program.

BACKGROUND ART

Inhalation devices that generate substances to be inhaled by a user 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".
In an inhalation device of the type which generates an aerosol by heating an aerosol source, it is desirable for the temperature at which the aerosol source is heated to be precisely controlled. In this regard, PTL 1 below discloses technology for controlling the temperature at which an aerosol source is heated, while taking account of deterioration of the inhalation device over time.

CITATION LIST

PATENT LITERATURE

PTL 1: JP 2021-531768 A

SUMMARY OF INVENTION

TECHNICAL PROBLEM

However, the technology disclosed in PTL 1 has only recently been developed, and there is still room for improvement in various aspects.
Accordingly, the present disclosure was devised in light of the problems above, and the objective of the present disclosure lies in providing an arrangement capable of further improving the quality of a user experience.

SOLUTION TO PROBLEM

In order to solve the problems above, one aspect of the present invention provides an aerosol-generating system comprising: a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; a heating unit for heating the substrate through the heat transfer portion; and a control unit for controlling operation of the heating unit, wherein the control unit controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.
The control unit may calculate, as the change over time in the length of the control period, a difference between the length of the control period and a reference value of the length of the control period, and, if the target value has been changed, may change the reference value based on the changed target value.
The control unit may control processing to change the target value defined in the control information, based on the parameter at a timing when the heating unit started heating.
The control unit may correct the length of the control period based on the parameter at the timing when the heating unit started heating, and may control the processing to change the target value defined in the control information, based on the post-correction length of the control period.
The control unit may change the target value defined in the control information only if the parameter at the timing when the heating unit started heating is included in a first range.
The control unit may change the target value defined in the control information only if the length of the control period is included in a second range.
The control unit may terminate control of the processing to change the target value defined in the control information if a cumulative amount of change in the target value defined in the control information exceeds a predetermined threshold.
The control unit may change the target value defined in the control information, based on the change over time in the length of the control period which was acquired when heating was started within a predetermined time from the heating unit ending the previous heating.
The control unit may control the processing to change the target value defined in the control information, based on a change over time in a temperature transition of the heat transfer portion which is estimated on the basis of the change over time in the length of the control period.
The control unit may change the target value defined in the control information if the number of times that a change over time in the temperature of the heat transfer portion, which is estimated on the basis of the change over time in the length of the control period, satisfied a predetermined condition, reaches a first number of times, and the first number of times may be two or more.
The control unit may change the target value defined in the control information if the number of times that the change over time in the temperature of the heat transfer portion, which is estimated on the basis of the change over time in the length of the control period, continuously satisfied the predetermined condition, reaches a second number of times, and the second number of times may be two or more.
The heating unit may be laminated on the heat transfer portion with a pressure-sensitive adhesive layer interposed.
The heat transfer portion may be a cylindrical body having an opening into which the substrate is inserted, and the heating unit may be arranged on the outer periphery of the cylindrical body.
Furthermore, in order to solve the problems 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 heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; and a heating unit for heating the substrate through the heat transfer portion, and wherein the control method comprises controlling operation of the heating unit, and controlling operation of the heating unit comprises controlling operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and controlling processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.
Furthermore, in order to solve the problems above, another aspect of the present invention provides a program executed by means of a computer for controlling an aerosol-generating system, wherein the aerosol-generating system comprises: a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; and a heating unit for heating the substrate through the heat transfer portion, and wherein the program causes the computer to function as a control unit for controlling operation of the heating unit, and the control unit controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, the present disclosure provides an arrangement capable of further improving the quality of a user experience.

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 an example of a heating mechanism of an inhalation device according to the embodiment.
Fig. 3 is a graph showing resistance and temperature of a heating unit when temperature control is performed on the basis of the heating profile shown in Table 1, and also showing an example of a transition of the temperature of an accommodating portion.
Fig. 4 is a graph showing the results of an experiment relating to progression of heater aging.
Fig. 5 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to the embodiment.
Fig. 6 is a graph showing the results of an experiment to investigate the relationship between initial resistance of the heating unit and duration of a Oth control period.
Fig. 7 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a first variant example.
Fig. 8 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a second variant example.
Fig. 9 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a third variant example.
Fig. 10 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a fourth variant example.
Fig. 11 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a fifth variant example.
Fig. 12 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a sixth variant example.
Fig. 13 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device according to a seventh variant example.
Fig. 14 is a graph showing the results of an experiment to verify the effects of the technology according to the present disclosure.

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.

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. Alternatively, 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 source unit 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 condenser 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 lightemitting device which emits light, a display device which displays images, a sound output device which outputs sound, or a vibration device which vibrates, etc., for example.
The memory unit 114 stores various types of information for operation of the inhalation device 100. The memory unit 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 a columnar internal space 141. An air flow path 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 path 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 includes 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 part 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 path, 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.

2. Technical Features

(1) Heating mechanism of inhalation device 100

Fig. 2 is a diagram to illustrate an example of a heating mechanism of the inhalation device 100 according to the embodiment. As shown in fig. 2, a pressure-sensitive adhesive film 145, the heating unit 121, and a heat diffusion layer 146 are laminated in succession on the outer periphery of the accommodating portion 140 and from an inner side to an outer side of the accommodating portion 140.
The pressure-sensitive adhesive film 145 is a film-like member with pressure-sensitive adhesion properties. As shown in fig. 2, the pressure-sensitive adhesive film 145 has a laminated configuration comprising a pressure-sensitive adhesive layer 145a, a base film 145b, and a pressure-sensitive adhesive layer 145c. The pressure-sensitive adhesive layer 145a and the pressure-sensitive adhesive layer 145c are layers with pressure-sensitive adhesion properties formed by material having a predetermined heat resistance, such as silicone, for example. The base film 145b is a film-like member formed by a resin having a predetermined heat resistance, such as polyimide (PI), for example. The pressure-sensitive adhesive film 145 is constructed by coating both sides of the base film 145b with a pressure-sensitive adhesive to form the pressure-sensitive adhesive layer 145a and the pressure-sensitive adhesive layer 145c, for example. The pressure-sensitive adhesive film 145 comprises the pressure-sensitive adhesive layer 145a and the pressure-sensitive adhesive layer 145c on both sides of the base film 145b and therefore adheres to each of the members provided adjacently thereto. That is to say, the pressure-sensitive adhesive film 145 adheres to the accommodating portion 140 and to the heating unit 121.
As shown in fig. 2, the heating unit 121 has a laminated configuration comprising a base film 121a, a conductive track 121b, a pressure-sensitive adhesive layer 121c, and a cover film 121d. The base film 121a and the cover film 121d are film-like members formed by a resin having a predetermined heat resistance, such as polyimide (PI), for example. The conductive track 121b is a heating resistor which generates heat by means of electrical resistance when a voltage is applied, and which is formed by a conductor such as SUS (Steel Use Stainless), for example. The pressure-sensitive adhesive layer 121c is a layer with pressure-sensitive adhesion properties formed by a material having a predetermined heat resistance, such as silicone, for example. The heating unit 121 is constructed, for example, by printing or vapor-depositing, etc. a circuit formed by the conductive track 121b on the base film 121a, and then covering this assembly with the base film 121d which has been coated with a pressure-sensitive adhesive to form the pressure-sensitive adhesive layer 121c.
The heat diffusion layer 146 is a sheet-like member formed by a material having predetermined heat transfer properties, such as graphite. As shown in fig. 2, the heat diffusion layer 146 is further laminated on the outside of the heating unit 121 and diffuses heat of the heating unit 121 to an outside surface of the accommodating portion 140. This configuration enables heat of the heating unit 121 to be efficiently transmitted to the accommodating portion 140.
The heating unit 121 is fixed to the accommodating portion 140 by means of the pressure-sensitive adhesive film 145. The heating unit 121 therefore heats the accommodating portion 140 from the outside. The heating unit 121 then heats, through the accommodating portion 140, the stick-type substrate 150 which is accommodated in the accommodating portion 140. That is to say, the temperature of the accommodating portion 140 is raised by heat transfer from the heating unit 121, and the stick-type substrate 150 contacting an inner wall of the accommodating portion 140 is heated. The accommodating portion 140 is an example of a heat transfer portion arranged to be capable of contacting the stick-type substrate 150 containing an aerosol source.
Here, as shown in fig. 2, the heating unit 121 is laminated on the accommodating portion 140 with the pressure-sensitive adhesive film 145 interposed. Heat of the heating unit 121 is therefore transmitted to the accommodating portion 140 through the pressure-sensitive adhesive film 145, as shown by the arrows 149. The pressure-sensitive adhesive film 145 is repeatedly heated by the heating unit 121, and may degenerate in the process of being repeatedly heated by the heating unit 121. The heating characteristics of the inhalation device 100 may change over time as a result. This will be described in detail later.

(2) 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. The resistance of the heating unit 121 is an example of a parameter corresponding to the temperature at which the aerosol source is heated. It should be noted that 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). This is because the electrical resistance value of the heating resistive element varies with temperature. A target value of the resistance of the heating unit 121 (also referred to below as the "target resistance") is an example of a target value of a parameter corresponding to the temperature at which the aerosol source is heated. It is assumed hereinafter that the resistance of the heating unit 121 rises as the temperature of the heating unit 121 rises.
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 resistance. 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 operation of the heating unit 121 so that the resistance of the heating unit 121 transitions in the same way as the target resistance 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.
The period from the start to the end of the processing to generate 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 a timing at which a sufficient amount of aerosol is no longer being generated. The heating session comprises a preheating period and a puffing-possible period following the preheating 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.
Moreover, 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 a heating profile is shown in Table 1 below. Table 1 shows information in the heating profile relating to the preheating period and the first part of the puffing-possible period.

TABLE 1

Table 1. Example of heating profile
Control period			Time-series transition of target resistance	Power supply parameter
Category	Name	Duration	Time-series transition of target resistance	ON/OFF
Preheating period	0th control period	-	Increase to T₀ mΩ (99.5% of T₁ mΩ)	ON
Preheating period	First control period	18 seconds	Increase to T₁ mΩ and maintain	ON
Puffing-possible period	Second control period	5 seconds	Maintain T₁ mΩ	ON
	Third control period	-	Decrease to T₃ mΩ	OFF
	...	...	...	...

As shown in Table 1, the heating profile is divided into multiple control periods, and a duration, time-series transition of the target resistance, and ON/OFF of the power supply are defined for each control period. In the example shown in Table 1, the heating profile is divided into four or more control periods. A time-series transition of the target resistance is then defined for each control period.
Time control may be implemented in each control period. Time control is control in which the end of each control period is triggered by the elapse of a predetermined time (i.e., the duration set for the relevant control period). It should be noted that when time control is implemented, the rate of change of the resistance of the heating unit 121 may be controlled so that the resistance of the heating unit 121 reaches the target resistance at the end of the duration. Furthermore, if time control is implemented, the resistance of the heating unit 121 may be controlled so that the resistance of the heating unit 121 reaches the target resistance partway through the duration and thereafter the resistance of the heating unit 121 is maintained at the target resistance until the duration has passed. In the example shown in Table 1, time control is implemented in the first control period and the second control period.
In some cases, time control is not implemented in each control period. If time control is not implemented, the end of each control period is triggered by the resistance of the heating unit 121 reaching a predetermined resistance (i.e., the target resistance set for each control period). The duration of control periods in which time control is not implemented therefore increases or decreases according to the rate of temperature change. In the example shown in Table 1, time control is not implemented in the Oth control period or the third control period.
According to the heating profile shown in Table 1, the 0th control period is a control period in which the resistance (i.e., the temperature) of the heating unit 121 increases rapidly. In the Oth control period, the duty ratio of power pulses applied to the heating unit 121 may be 100%, and the temperature of the heating unit 121 increases most rapidly. The target resistance in the Oth control period is set, based on the target resistance in the first control period, as a value at which the corresponding temperature of the heating unit 121 is lower than for the target resistance in the first control period. In the example shown in Table 1, the target resistance in the 0th control period is 99.5% of the target resistance in the first control period.
The first control period is a control period in which the resistance of the heating unit 121 is slowly increased and maintained. The stick-type substrate 150 can be warmed through to the middle by providing the first control period. A sufficient quantity of aerosol can be delivered to the user from the start of the puffing-possible period as a result.
The second control period is a control period in which the resistance (i.e., the temperature) of the heating unit 121 is maintained at the target resistance of the first control period. That is to say, the same target resistance as in the first control period is set in the second control period. The puffing-possible period starts from the second control period.
The third control period is a control period in which the resistance (i.e., the temperature) of the heating unit 121 decreases. In the third control period, power supply to the heating unit 121 is turned OFF, so the resistance of the heating unit 121 decreases rapidly.
An example of the heating profile was described above.
Here, the heating unit 121 heats the stick-type substrate 150 through the accommodating portion 140, as described above with reference to fig. 2. It is desirable for the temperature of the accommodating portion 140 to be precisely controlled because it is the accommodating portion 140 which directly heats the stick-type substrate 150. The relationship between the temperature transition of the heating unit 121 and the temperature transition of the accommodating portion 140 will be described with reference to fig. 3.
Fig. 3 is a graph showing the resistance and temperature of the heating unit 121 when temperature control is performed on the basis of the heating profile shown in Table 1, and also showing an example of the transition of the temperature of the accommodating portion 140. The horizontal axis of the graph 10 denotes time (seconds). The vertical axis of the graph 10 denotes resistance (mΩ) and temperature (°C). In the present description, a resistance of the heating unit 121 of 1 mΩ is assumed to correspond to a temperature of the heating unit 121 of 1°C.
The line 11 indicates the temperature and resistance transition of the heating unit 121. Referring to the line 11, the resistance of the heating unit 121 transitions in the same way as the transition of the target resistance defined in the heating profile shown in Table 1. That is to say, the resistance of the heating unit 121 rapidly increases to T₀ mΩ in the 0th control period, then slowly increases to T₁ mΩ in the first control period and is maintained at that level until the end of the second control period. In the same way, the temperature of the heating unit 121 rapidly increases to T₀°C in the Oth control period, then slowly increases to T₁°C in the first control period and is maintained at that level until the end of the second control period. It should be noted that the Oth control period in which time control is not performed finishes after 7 seconds.
The line 12 indicates the transition of the temperature of the accommodating portion 140. Referring to the line 12, the temperature of the accommodating portion 140 increases rapidly in the Oth control period, then slowly increases in the first control period and is maintained at that level until the end of the second control period, in the same way as the temperature transition of the heating unit 121. However, the temperature of the accommodating portion 140 transitions at a lower temperature than the temperature of the heating unit 121. For example, the temperature of the heating unit 121 reaches a maximum of T₁°C in the first control period and the second control period, whereas the temperature of the accommodating portion 140 reaches a maximum of T₁'°C, which is lower than T₀ and T₁.

(3) Heater aging

The heating characteristics of the inhalation device 100 having the heating mechanism described above with reference to fig. 2 change over time. To be more specific, the temperature of the heating unit 121 increases less readily and the temperature of the accommodating portion 140 increases more readily as the inhalation device 100 is used for a longer period of time, that is, as heating is repeated more times by the heating unit 121. A first factor is that repeated heating by the heating unit 121 causes degeneration of the pressure-sensitive adhesive film 145 (especially the pressure-sensitive adhesive layers 145a and 145c), leading to closer contact between the heating unit 121 and the accommodating portion 140. A second factor is that repeated heating by the heating unit 121 causes closer contact between the heat diffusion layer 146 and the accommodating portion 140. These factors increase heat transfer from the heating unit 121 to the accommodating portion 140. The temperature of the heating unit 121 increases less readily, and the temperature of the accommodating portion 140 increases more readily as a result. It should be noted that there are greater changes over time in these heating characteristics as the watt density of the heating unit 121 (more specifically, the circuit configured by the conductive track 121b) increases.
These changes over time in the heating characteristics will also be referred to below as "heater aging". Through experiments, the present inventors established that progression of heater aging is apparent at the end time of the 0th control period (that is, the duration of the 0th control period). The results of the experiments carried out by the present inventors will be described below.

- First experiment

The present inventors reproduced heater aging by repeating a heater aging treatment multiple times, the heater aging treatment comprising increasing the temperature of the heating unit 121 to 320°C, then reducing the temperature to 260°C, and then cooling the heating unit 121. The heater aging treatment being performed once will also be referred to here as "1 cycle", and the number of times of performing the heater aging treatment will also be referred to here as the "number of cycles". The present inventors then performed heating based on the heating profile shown in Table 1 at multiple cycle time points, and measured the duration of the Oth control period. A cycle time point is the timing at which the number of cycles has reached a predetermined number. Moreover, the present inventors carried out the experiment using four inhalation devices 100 to take account of variations in each inhalation device 100. This experiment was carried out under an environment of 25°C. The results of the experiment will be described below with reference to fig. 4.
Fig. 4 is a graph showing the results of the experiment relating to progression of heater aging. The horizontal axis in the graph 20 shown in fig. 4 denotes the duration of the Oth control period. The vertical axis of the graph 20 denotes the maximum temperature of the accommodating portion 140. Here, the maximum temperature of the accommodating portion 140 denotes the maximum temperature of the accommodating portion 140 in a period until there is a drop in the temperature of the accommodating portion 140 which increased in the 0th control period (i.e., the first control period and the second control period in the example shown in Table 1 and fig. 3). Typically, the maximum temperature of the accommodating portion 140 is often the maximum temperature in the second control period. The maximum temperature of the accommodating portion 140 may of course also be the maximum temperature in the first control period. In the graph 20, the relationship between the duration of the 0th control period and the maximum temperature of the accommodating portion 140 is plotted for each of the four inhalation devices 100 (No. 1-No. 4). These plots move steadily from the bottom left to the top right of the graph 20 as the number of cycles increases. That is to say, the duration of the Oth control period became longer and the maximum temperature of the accommodating portion 140 increased as heater aging progressed in all four inhalation devices 100. The lines 21-24 denote regression lines inclined by a regression coefficient showing the relationship between the duration of the 0th control period and the maximum temperature of the accommodating portion 140 in each of the four inhalation devices 100 (No. 1-No. 4). It can be seen from the lines 21-24 that the maximum temperature of the accommodating portion 140 increases as the duration of the Oth control period becomes longer. It can also be seen that there is a linear relationship between the duration of the Oth control period and the maximum temperature of the accommodating portion 140. That is to say, it is suggested that the maximum temperature of the accommodating portion 140 can be estimated on the basis of the duration of the 0th control period.

- Second experiment

The present inventors cross-validated the data obtained in the first experiment. The present inventors used the data obtained from any one of the four inhalation devices 100 as data for prediction, and used, as a prediction model, a regression model with the average value of the regression coefficients of the data obtained from the other three inhalation devices 100 as the regression coefficient. The present inventors then estimated the amount of change in the maximum temperature of the accommodating portion 140 from the preceding cycle time point at each cycle time point by inputting to the prediction model the change in duration of the Oth control period from the preceding cycle time point, and evaluated the difference between the predicted value and the measured value. The evaluation results are shown in Table 2 below.

TABLE 2

Table 2. Results of cross-validation
Validation setting		Results of cross-validation (difference between predicted value and measured value)
Data for prediction	Data used in prediction model	Average value [°C]	Standard deviation [°C]
No. 1	No. 2, 3, 4	0.94	0.88
No. 2	No. 1, 3, 4	1.09	0.57
No. 3	No. 1, 2, 4	1.43	0.65
No. 4	No. 1, 2, 3	1.39	0.95

Taking the average of the results of the cross-validation shown in Table 2 above, the difference between the estimated value and the measured value for the amount of change in the maximum temperature of the accommodating portion 140 is assumed to be 4°C or less based on average value ±3×standard deviation. It can be seen from the above that the change in the maximum temperature of the accommodating portion 140 can be accurately estimated on the basis of the change over time in the duration of the Oth control period.

(4) Updating of heating profile as heating characteristics change over time

The control unit 116 controls processing to change the target resistance defined in the heating profile, based on the change over time in the length of the control period from the start of heating by the heating unit 121 until the resistance of the heating unit 121 reaches a specific target value. More specifically, the control unit 116 controls processing to change the target resistance defined in the heating profile, based on the change over time in the duration of the 0th control period. "Change over time" as referred to here means changes caused by repeated heating by the heating unit 121. The progression of heater aging is apparent in changes over time in the duration of the 0th control period, as demonstrated by the results of the first and second experiments. The control unit 116 therefore updates the heating profile in order to cancel out changes over time in the temperature transition of the accommodating portion 140, which are estimated from the change over time in the duration of the Oth control period. By virtue of this configuration, even if the heating characteristics of the inhalation device 100 change over time, the temperature transition of the accommodating portion 140 can be restored to the state before the change over time in the heating characteristics of the inhalation device 100. This makes it possible to suppress a deterioration in the quality of the user experience associated with changes over time in the heating characteristics of the inhalation device 100, making it possible to improve the quality of the user experience as a result.
The control unit 116 may calculate, as the change over time in the duration of the 0th control period, the difference between the duration of the 0th control period and a reference value of the duration of the 0th control period. This configuration enables changes over time in the duration of the Oth control period to be ascertained quantitatively. It should be noted that the duration of the 0th control period can be measured by means of the control unit 116. The measured duration of the 0th control period may also be referred to below as the "measured value", in order to make a distinction with the reference value.
If the target resistance has been changed, the control unit 116 may change the reference value of the duration of the Oth control period based on the changed target resistance. As an example, when heating based on the heating profile is implemented after the target resistance has been changed, the control unit 116 may utilize, as the reference value, the measured value of the duration of the 0th control period measured on the basis of the changed target resistance. As another example, the control unit 116 may change the reference value by subtracting a length corresponding to the extent of a drop in the target resistance from the reference value before the change. This configuration enables changes over time in the duration of the Oth control period to be monitored appropriately.
The specific details of the processing to update the heating profile on the basis of changes over time in the heating characteristics will be described below.
The control unit 116 first of all estimates a change over time in the temperature transition of the accommodating portion 140, based on the change over time in the duration of the Oth control period. For example, the control unit 116 estimates the amount of change (that is, the extent of increase) in the maximum temperature of the accommodating portion 140, based on the regression model showing the relationship between the duration of the Oth control period and the maximum temperature of the accommodating portion 140, and the amount of change (that is, the extent of increase) in the duration of the Oth control period. For example, the control unit 116 may estimate the amount of change in the maximum temperature of the accommodating portion 140 by using the following mathematical formula (1).
Math. 1 ${ΔT}_{CUP} = C_{1} \times (L - L_{0})$
Here, ΔT_CUP is the estimated value of the amount of change in the maximum temperature of the accommodating portion 140. C₁ is the regression coefficient of a regression model indicating the relationship between the duration of the Oth control period and the maximum temperature of the accommodating portion 140. The average value of regression coefficients indicating the relationship between the duration of the Oth control period and the maximum temperature of the accommodating portion 140, which were obtained for the four inhalation devices 100 in the first experiment, may be utilized for the regression coefficient C₁. L is the measured value of the duration of the 0th control period. L₀ is the reference value of the duration of the 0th control period.
The control unit 116 then controls the processing to change the target resistance defined in the heating profile, based on the estimated change over time in the temperature transition of the accommodating portion 140. For example, the control unit 116 reduces the target resistance of the heating unit 121 defined in the heating profile, so that the temperature of the heating unit 121 drops by the estimated extent of increase in the maximum temperature of the accommodating portion 140. For example, the control unit 116 can reduce the target resistance of the heating unit 121 defined in the heating profile by 4 mΩ when the estimated extent of increase in the maximum temperature of the accommodating portion 140 is 4°C. By virtue of this configuration, the temperature of the accommodating portion 140 which increased due to a change over time in the heating characteristics of the inhalation device 100 can be reduced to the temperature before the change over time in the heating characteristics of the inhalation device 100.
The control unit 116 may reduce the target resistance of the heating unit 121 defined in the heating profile only when the estimated extent of increase in the maximum temperature of the accommodating portion 140 is equal to or greater than a predetermined threshold (also referred to below as the "heater aging determination threshold"). This configuration allows the heating profile to be updated each time heater aging progresses to a certain extent. In other words, the processing load on the inhalation device 100 can be lessened by restricting frequent updates to the heating profile.
It should be noted that, as the processing to change the target resistance defined in the heating profile, the control unit 116 may also reduce the target resistance in the Oth control period and the first control period, from among the target resistances defined in the heating profile. In that case, the control unit 116 may reduce the target resistance in the first control period based on the estimated change over time in the temperature transition of the accommodating portion 140, and may then set the target resistance in the Oth control period at 99.5% of the target resistance in the first control period following the change. For example, the control unit 116 may reduce the target resistance in the first control period defined in the heating profile by 4 mΩ when the estimated extent of increase in the maximum temperature of the accommodating portion 140 is 4°C. The control unit 116 may then set the target resistance in the Oth control period at 99.5% of the target resistance in the first control period after the 4 mΩ reduction. By virtue of this configuration, the duration of the Oth control period is shortened, and the maximum temperature of the accommodating portion 140 can be restored to the temperature before the change over time in the heating characteristics of the inhalation device 100. It should be noted that the control unit 116 may also reduce the target resistance in the second control period in the same way as the target resistance in the first control period.
Alternatively, as the processing to change the target resistance defined in the heating profile, the control unit 116 may also reduce the target resistance in all of the control periods defined in the heating profile. By virtue of this configuration, the temperature transition of the accommodating portion 140 can be restored to the state before the change over time in the heating characteristics of the inhalation device 100 over the entire heating session.
An example of the flow of processing implemented by means of the inhalation device 100 according to the embodiment will be described below with reference to fig. 5. Fig. 5 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the embodiment.
As shown in fig. 5, the control unit 116 first of all implements processing to set a reference value of the duration of the Oth control period (step S102). The processing relating to step S102 is implemented when the reference value of the duration of the 0th control period has not been set. That is to say, the processing relating to step S102 is implemented immediately after the inhalation device 100 has been shipped from the factory. However, the processing relating to step S102 is preferably omitted during the initial heating immediately after the inhalation device 100 has been shipped from the factory, and is implemented during the second and subsequent heating. This is because the heating characteristics of the inhalation device 100 may be unstable during the initial heating immediately after shipping from the factory. Furthermore, the processing relating to step S102 is implemented each time the heating profile is updated.
Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the 0th control period which has been set (step S104).
Step S102 includes steps S112-S116. Furthermore, step S104 includes steps S118-S128. Each of these steps will be described in detail below.
As shown in fig. 5, the control unit 116 first of all implements heating based on the heating profile (step S112). For example, the control unit 116 can implement heating based on the heating profile when a user operation to instruct the start of heating has been detected. Pressing a button provided on the inhalation device 100 is an example of a user operation to instruct the start of heating. Inserting the stick-type substrate 150 into the accommodating portion 140 is another example of a user operation to instruct the start of heating.
Next, the control unit 116 measures the duration of the Oth control period for the heating based on the heating profile implemented in step S112 (step S114).
The control unit 116 then causes the memory unit 114 to store the measured value of the duration of the 0th control period which was measured in step S114, as the reference value of the duration of the Oth control period (step S116).
After this, the control unit 116 implements heating based on the heating profile (step S118).
Next, the control unit 116 measures the duration of the 0th control period for the heating based on the heating profile implemented in step S118 (step S120).
Next, the control unit 116 calculates the difference between the measured value and the reference value of the duration of the Oth control period (step S122). For example, the control unit 116 calculates the difference between the reference value of the duration of the Oth control period stored in step S116, and the measured value of the duration of the 0th control period measured in step S120.
Next, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140, based on the difference between the measured value and the reference value of the duration of the 0th control period (step S124). For example, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140 by using mathematical formula (1) indicated above.
Next, the control unit 116 determines whether or not the estimated amount of change in the maximum temperature of the accommodating portion 140 is equal to or greater than the heater aging determination threshold (step S126). The heater aging determination threshold may be freely set, and may be 4°C, for example.
If the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be less than the heater aging determination threshold (step S126: NO), then the processing returns to step S118.
On the other hand, if the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be equal to or greater than the heater aging determination threshold (step S126: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S128). For example, the control unit 116 may reduce the target resistance in the first control period defined in the heating profile by 4 mΩ when the estimated extent of increase in the maximum temperature of the accommodating portion 140 is 4°C. The control unit 116 may then set the target resistance in the Oth control period at 99.5% of the target resistance in the first control period following the change.
After this, the processing returns to step S112.

3. Variant example

(1) First variant example

The resistance of the heating unit 121 at the timing when the heating unit 121 started heating (also referred to below as the "initial resistance") may vary. As an example, the initial resistance of the heating unit 121 increases with continuous smoking. Continuous smoking as referred to here means that the inhalation device 100 continuously implements heating based on the heating profile at short intervals. As another example, the initial resistance of the heating unit 121 may rise or fall depending on the ambient temperature. The duration of the 0th control period may then vary according to the initial resistance of the heating unit 121.
The present inventors therefore carried out an experiment (also referred to below as the third experiment) into the relationship between the initial resistance of the heating unit 121 and the duration of the 0th control period. More specifically, the present inventors started heating based on the heating profile shown in Table 1 after setting the initial resistance of the heating unit 121 at a predetermined value, then measured the duration of the Oth control period. Note that the present inventors carried out this experiment using the four inhalation devices 100 used in the first experiment, under an environment of 25°C and at the time of 6000 cycles. Moreover, the present inventors carried out the experiment using four inhalation devices 100 to take account of variations in each inhalation device 100. The results of the experiment will be described below with reference to fig. 6.
Fig. 6 is a graph showing the results of the experiment to investigate the relationship between initial resistance of the heating unit 121 and duration of the Oth control period. The vertical axis in the graph 30 denotes the duration of the 0th control period. The horizontal axis in the graph 30 denotes the initial resistance of the heating unit 121. In the graph 30, the relationship between the initial resistance of the heating unit 121 and the duration of the 0th control period is plotted for each of the four inhalation devices 100 (No. 1-No. 4). The lines 31-34 denote regression lines inclined by a regression coefficient showing the relationship between the initial resistance of the heating unit 121 and the duration of the 0th control period in each of the four inhalation devices 100 (No. 1-No. 4). It can be seen from the lines 31-34 that there is a linear relationship between the initial resistance of the heating unit 121 and the duration of the Oth control period. To be more specific, it can be seen that the duration of the Oth control period becomes shorter as the initial resistance of the heating unit 121 becomes higher, i.e., as the temperature of the heating unit 121 at the start of heating becomes higher.
Note that the initial resistance of the heating unit 121 can be measured by means of the control unit 116. The measured initial resistance of the heating unit 121 may also be referred to below as the "measured value", in order to make a distinction with a reference value which will be described later.
According to the results of the experiments described above, the duration of the Oth control period may increase or decrease depending on the initial resistance of the heating unit 121. The control unit 116 may therefore control the processing to change the target resistance defined in the heating profile, based on the initial resistance of the heating unit 121. This configuration enables changes over time in the Oth control period to be appropriately monitored while taking account of increases or decreases in the duration of the Oth control period commensurate with the initial resistance of the heating unit 121. The heating profile can be suitably updated as a result.
To be more specific, the control unit 116 may correct the duration of the Oth control period on the basis of the initial resistance of the heating unit 121. For example, based on the measured value of the initial resistance of the heating unit 121 and the measured value of the duration of the Oth control period, the control unit 116 estimates the duration of the Oth control period when the initial resistance of the heating unit 121 is assumed to be the reference value, and uses this duration as the post-correction duration of the Oth control period. In this process, the control unit 116 may calculate the amount of correction of the duration of the Oth control period on the basis of the regression model indicating the relationship between the initial resistance of the heating unit 121 and the duration of the 0th control period, and the difference between the measured value and the reference value of the initial resistance of the heating unit 121. The control unit 116 can then calculate the post-correction duration of the 0th control period by correcting the measured value of the duration of the Oth control period on the basis of the amount of correction of the duration of the Oth control period. For example, the control unit 116 may calculate the post-correction duration of the Oth control period by using the following mathematical formula (2).
Math. 2 $L * = L - C_{2} \times (R_{0} - R)$
Here, L* is the duration of the Oth control period which would be measured if the initial resistance of the heating unit 121 were the reference value. C₂ is the regression coefficient of the regression model. The average value of regression coefficients indicating the relationship between the initial resistance of the heating unit 121 and the duration of the Oth control period, which were obtained for the four inhalation devices 100 in the third experiment, may be utilized as the regression coefficient C₂. R is the measured value of the initial resistance of the heating unit 121. R₀ is the reference value of the initial resistance of the heating unit 121. It should be noted that the reference value R₀ of the initial resistance of the heating unit 121 may be set as the measured value of the resistance of the heating unit 121 when the temperature of the heating unit 121 is normal temperature, or may be written into the memory unit 114 as a default in a calibration process.
The control unit 116 then controls the processing to change the target resistance defined in the heating profile, based on the post-correction duration of the Oth control period. That is to say, the control unit 116 estimates the change over time in the temperature transition of the accommodating portion 140 based on the change over time in the post-correction duration of the Oth control period, and controls the processing to change the target resistance defined in the heating profile, based on the estimated change over time in the temperature transition of the accommodating portion 140. The specific details of the processing may be the same as in the embodiment described above, except for using the post-correction duration of the 0th control period as the duration of the 0th control period. This configuration allows the heating profile to be suitably updated while eliminating the effects of the initial resistance of the heating unit 121 on the duration of the Oth control period.
The reference value of the duration of the 0th control period may also be affected by the initial resistance of the heating unit 121 when updating occurs. When the reference value of the duration of the 0th control period is updated also, the control unit 116 preferably corrects the duration of the Oth control period based on the initial resistance of the heating unit 121, and uses the post-correction duration of the Oth control period as the reference value. In that case, the control unit 116 may estimate the amount of change in the maximum temperature of the accommodating portion 140 by using the following mathematical formula (3) instead of mathematical formula (1) indicated above.
Math. 3 ${ΔT}_{CUP} = C_{1} \times (L * - L_{0} *)$
Here, L₀* is the post-correction reference value of the duration of the 0th control period, which is the duration of the Oth control period corrected using mathematical formula (2) indicated above for updating, for example.
An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 7. Fig. 7 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 7, the control unit 116 first of all implements processing to set a reference value of the duration of the 0th control period (step S202). The processing relating to step S202 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the Oth control period which has been set (step S204). Step S202 includes steps S212-S220. Furthermore, step S204 includes steps S222-S236. Each of these steps will be described in detail below.
As shown in fig. 7, the control unit 116 first of all implements heating based on the heating profile (step S212).
Next, the control unit 116 measures the initial resistance of the heating unit 121 for the heating based on the heating profile implemented in step S212 (step S214). For example, the control unit 116 acquires, as the measured value of the initial resistance of the heating unit 121, the resistance of the heating unit 121 at a point in time when 0.01 seconds have elapsed since heating started in the heating based on the heating profile implemented in step S212.
Next, the control unit 116 measures the duration of the Oth control period for the heating based on the heating profile implemented in step S212 (step S216).
Next, the control unit 116 corrects the measured value of the duration of the 0th control period measured in step S216, based on the measured value of the initial resistance of the heating unit 121 measured in step S214 (step S218). For example, the control unit 116 calculates the post-correction measured value of the 0th control period by using mathematical formula (2) indicated above.
Next, the control unit 116 causes the memory unit 114 to store the post-correction measured value of the 0th control period as the post-correction reference value of the duration of the Oth control period (step S220).
After this, the control unit 116 implements heating based on the heating profile (step S222).
Next, the control unit 116 measures the initial resistance of the heating unit 121 for the heating based on the heating profile implemented in step S222 (step S224).
Next, the control unit 116 measures the duration of the Oth control period for the heating based on the heating profile implemented in step S222 (step S226).
Next, the control unit 116 corrects the measured value of the duration of the 0th control period measured in step S226, based on the measured value of the initial resistance of the heating unit 121 measured in step S224 (step S228).
Next, the control unit 116 calculates the difference between the post-correction measured value of the duration of the Oth control period and the post-correction reference value of the duration of the Oth control period (step S230).
Next, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140, based on the difference between the post-correction measured value of the duration of the 0th control period and the post-correction reference value of the duration of the Oth control period (step S232). For example, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140 by using mathematical formula (3) indicated above.
Next, the control unit 116 determines whether or not the estimated amount of change in the maximum temperature of the accommodating portion 140 is equal to or greater than the heater aging determination threshold (step S234).
If the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be less than the heater aging determination threshold (step S234: NO), then the processing returns to step S222.
On the other hand, if the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be equal to or greater than the heater aging determination threshold (step S234: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S236).
After this, the processing returns to step S212.
Moreover, it was confirmed experimentally that the difference between the estimated value and the measured value of the amount of change in the maximum temperature of the accommodating portion 140 in this variant example was 0.8°C smaller on average than in the embodiment described above.

(2) Second variant example

The control unit 116 may change the target resistance defined in the heating profile only when the initial resistance of the heating unit 121 is included in a first range. As an example, the first range may be set on the basis of the reference value of the initial resistance of the heating unit 121. That is to say, the control unit 116 may change the target resistance defined in the heating profile only when the measured value of the initial resistance of the heating unit 121 is close to the reference value of the initial resistance of the heating unit 121. Meanwhile, the control unit 116 need not change the target resistance defined in the heating profile when the measured value of the initial resistance of the heating unit 121 is far from the reference value of the initial resistance of the heating unit 121. As another example, the first range may be set in a fixed manner as a range between predetermined values.
Large errors may arise in predictions using the regression model if the initial resistance of the heating unit 121 is abnormally large or abnormally small due to the effects of continuous smoking or ambient temperature, etc. In this regard, the configuration above makes it possible to ensure that the heating profile is not updated in a situation where large errors might arise in the prediction using the regression model, therefore making it possible to prevent unsuitable changes to the heating profile caused by errors. It is possible to prevent a deterioration in the quality of the user experience as a result.
An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 8. Fig. 8 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 8, the control unit 116 first of all implements processing to set a reference value of the duration of the Oth control period (step S302). The processing relating to step S302 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the Oth control period which has been set (step S304). Step S302 includes steps S312-S320. Furthermore, step S304 includes steps S322-S336. Each of these steps will be described in detail below.
As shown in fig. 8, the control unit 116 first of all implements heating based on the heating profile (step S312).
Next, the control unit 116 measures the initial resistance of the heating unit 121 for the heating based on the heating profile implemented in step S312 (step S314).
Next, the control unit 116 determines whether or not the measured value of the initial resistance of the heating unit 121 measured in step S314 is included in the first range (step S316). For example, the control unit 116 may define the first range as a range of between R₀-0.02 Ω and R₀+0.01 Ω, based on the reference value R₀ of the initial resistance of the heating unit 121. In that case, the control unit 116 determines whether or not the measured value R of the initial resistance of the heating unit 121 is included in the range of between R₀-0.02 Ω and R₀+0.01 Ω.
If it is determined that the measured value of the initial resistance of the heating unit 121 is not included in the first range (step S316: NO), then the processing returns to step S312.
Meanwhile, if it is determined that the measured value of the initial resistance of the heating unit 121 is included in the first range (step S316: YES), then the control unit 116 measures the duration of the 0th control period for the heating based on the heating profile implemented in step S312 (step S318).
The control unit 116 then causes the memory unit 114 to store the measured value of the duration of the 0th control period which was measured in step S318, as the reference value of the duration of the Oth control period (step S320).
After this, the control unit 116 implements heating based on the heating profile (step S322).
Next, the control unit 116 measures the initial resistance of the heating unit 121 for the heating based on the heating profile implemented in step S322 (step S324).
Next, the control unit 116 determines whether or not the measured value of the initial resistance of the heating unit 121 measured in step S324 is included in the first range (step S326).
If it is determined that the measured value of the initial resistance of the heating unit 121 is not included in the first range (step S326: NO), then the processing returns to step S322.
Meanwhile, if it is determined that the measured value of the initial resistance of the heating unit 121 is included in the first range (step S326: YES), then the control unit 116 measures the duration of the 0th control period for the heating based on the heating profile implemented in step S322 (step S328).
Next, the control unit 116 calculates the difference between the measured value and the reference value of the duration of the Oth control period, as a change over time of the duration of the 0th control period (step S330).
Next, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140, based on the difference between the measured value and the reference value of the duration of the 0th control period (step S332).
Next, the control unit 116 determines whether or not the estimated amount of change in the maximum temperature of the accommodating portion 140 is equal to or greater than the heater aging determination threshold (step S334).
If the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be less than the heater aging determination threshold (step S334: NO), then the processing returns to step S322.
On the other hand, if the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be equal to or greater than the heater aging determination threshold (step S334: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S336).
After this, the processing returns to step S312.
It should be noted that, in the embodiment above, it was confirmed experimentally that the difference between the estimated value and the measured value of the amount of change in the maximum temperature of the accommodating portion 140 deviated by a minimum of 9°C during continuous smoking. That is to say, this variant example makes it possible to prevent unsuitable changes to the heating profile in a situation where there is a minimum error of 9°C.

(3) Third variant example

The control unit 116 may change the target resistance defined in the heating profile only when the duration of the Oth control period is included in a second range. As an example, the second range may be set on the basis of the reference value of the duration of the 0th control period. As another example, the second range may be set in a fixed manner as a range between predetermined values.

The duration of the 0th control period may also become abnormally short or abnormally long if the initial resistance of the heating unit 121 is abnormally large or abnormally small due to the effects of continuous smoking or ambient temperature, etc. Accordingly, this configuration makes it possible to prevent a deterioration in the quality of the user experience for the same reasons as in the second variant example described above.

An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 9. Fig. 9 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 9, the control unit 116 first of all implements processing to set a reference value of the duration of the Oth control period (step S402). The processing relating to step S402 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the Oth control period which has been set (step S404). Step S402 includes steps S412-S418. Furthermore, step S404 includes steps S420-S432. Each of these steps will be described in detail below.
As shown in fig. 9, the control unit 116 first of all implements heating based on the heating profile (step S412).
Next, the control unit 116 measures the duration of the Oth control period for the heating based on the heating profile implemented in step S412 (step S414).
Next, the control unit 116 determines whether or not the measured value of the duration of the 0th control period measured in step S414 is included in the second range (step S416). For example, the control unit 116 may define the second range as a range of a predetermined number of seconds or greater. In that case, the control unit 116 determines whether or not the measured value of the duration of the Oth control period is equal to or greater than a predetermined number of seconds. This condition enables a determination as to whether or not continuous smoking is in progress, considering that the duration of the Oth control period is markedly shorter during continuous smoking.
If it is determined that the measured value of the duration of the Oth control period is not included in the second range (step S416: NO), then the processing returns to step S412.
Meanwhile, if it is determined that the measured value of the duration of the 0th control period is included in the second range (step S416: YES), then the control unit 116 causes the memory unit 114 to store the measured value of the duration of the 0th control period which was measured in step S414, as the reference value of the duration of the 0th control period (step S418).
After this, the control unit 116 implements heating based on the heating profile (step S420).
Next, the control unit 116 measures the duration of the Oth control period for the heating based on the heating profile implemented in step S420 (step S422).
Next, the control unit 116 determines whether or not the measured value of the duration of the 0th control period measured in step S422 is included in the second range (step S424).
If it is determined that the measured value of the duration of the Oth control period is not included in the second range (step S424: NO), then the processing returns to step S420.
Meanwhile, if it is determined that the measured value of the duration of the 0th control period is included in the second range (step S424: YES), then the control unit 116 calculates the difference between the measured value and the reference value of the duration of the 0th control period which was measured in step S422 (step S426).
Next, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140, based on the difference between the measured value and the reference value of the duration of the 0th control period (step S428).
Next, the control unit 116 determines whether or not the estimated amount of change in the maximum temperature of the accommodating portion 140 is equal to or greater than the heater aging determination threshold (step S430).
If the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be less than the heater aging determination threshold (step S430: NO), then the processing returns to step S420.
On the other hand, if the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be equal to or greater than the heater aging determination threshold (step S430: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S432).
After this, the processing returns to step S412.
It should be noted that, in the embodiment above, it was confirmed experimentally that the difference between the estimated value and the measured value of the amount of change in the maximum temperature of the accommodating portion 140 during continuous smoking deviated by a minimum of 9°C. That is to say, this variant example makes it possible to prevent unsuitable changes to the heating profile in a situation where there is a minimum error of 9°C.

(4) Fourth variant example

The control unit 116 may change the target resistance defined in the heating profile if the number of times that a change over time in the temperature transition of the accommodating portion 140, which is estimated on the basis of a change over time in the duration of the Oth control period, satisfied a predetermined condition (also referred to below as the "heater aging determination condition"), reaches a first number of times. The first number of times is any number of times, provided that it is two or more. The heater aging determination condition is a condition under which it can be determined that heater aging has progressed to a certain extent. As an example, the heater aging determination condition may be that the estimated amount of change in the maximum temperature of the accommodating portion 140 is equal to or greater than the heater aging determination threshold. Note that the processing described with reference to fig. 5 can also be counted as processing for when the first number of times is one.
Due to the effects of the initial resistance of the heating unit 121 and ambient temperature, etc., there is a risk of the heater aging determination condition accidentally being satisfied and of an erroneous determination that heater aging is progressing, despite the fact that heater aging has not actually progressed to a great extent. In this regard, the configuration above makes it possible to ensure that the heating profile is not updated if the heater aging determination condition has been accidentally satisfied. That is to say, the heating profile can be updated only when heater aging is definitely progressing.
An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 10. Fig. 10 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 10, the control unit 116 first of all implements processing to set a reference value of the duration of the Oth control period (step S502). The processing relating to step S502 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the Oth control period which has been set (step S504). Step S502 includes steps S512-S516. Furthermore, step S504 includes steps S518-S528. The processing relating to steps S512-S524 is the same as the processing relating to steps S112-S124 described with reference to fig. 5 and will therefore not be described in detail. Steps S526 and S528 will be described in detail below.
After step S524, the control unit 116 determines whether or not the number of times that the estimated amount of change in the maximum temperature of the accommodating portion 140 was equal to or greater than the heater aging determination threshold has reached the first number of times (step S526).
If it is determined that the number of times that the estimated amount of change in the maximum temperature of the accommodating portion 140 was equal to or greater than the heater aging determination threshold has not reached the first number of times (step S526: NO), then the processing returns to step S518.
On the other hand, if it is determined that the number of times that the estimated amount of change in the maximum temperature of the accommodating portion 140 was equal to or greater than the heater aging determination threshold has reached the first number of times (step S526: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S528).
After this, the processing returns to step S512.

(5) Fifth variant example

The control unit 116 may change the target resistance defined in the heating profile if the number of times that a change over time in the temperature of the accommodating portion 140, which is estimated on the basis of a change over time in the duration of the Oth control period, continuously satisfied the heater aging determination condition, reaches a second number of times. The second number of times is any number of times, provided that it is two or more. Note that the processing described with reference to fig. 5 can also be counted as processing for when the second number of times is one. This configuration makes it possible to update the heating profile only when heater aging is definitely progressing, for the same reasons as in the fourth variant example.
An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 11. Fig. 11 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 11, the control unit 116 first of all implements processing to set a reference value of the duration of the Oth control period (step S602). The processing relating to step S602 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the Oth control period which has been set (step S604). Step S602 includes steps S612-S616. Furthermore, step S604 includes steps S618-S628. The processing relating to steps S612-S624 is the same as the processing relating to steps S112-S124 described with reference to fig. 5 and will therefore not be described in detail. Steps S626 and S628 will be described in detail below.
After step S624, the control unit 116 determines whether or not the number of times that the estimated amount of change in the maximum temperature of the accommodating portion 140 was continuously equal to or greater than the heater aging determination threshold has reached the second number of times (step S626).
If it is determined that the number of times that the estimated amount of change in the maximum temperature of the accommodating portion 140 was continuously equal to or greater than the heater aging determination threshold has not reached the second number of times (step S626: NO), then the processing returns to step S618.
On the other hand, if it is determined that the number of times that the estimated amount of change in the maximum temperature of the accommodating portion 140 was continuously equal to or greater than the heater aging determination threshold has reached the second number of times (step S626: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S628).
After this, the processing returns to step S612.

(6) Sixth variant example

The control unit 116 may terminate the processing to change the target resistance defined in the heating profile if heater aging is presumed to have settled. As an example, the control unit 116 may terminate control of the processing to change the target resistance defined in the heating profile if a cumulative amount of change in the target resistance defined in the heating profile exceeds a predetermined threshold. As another example, the control unit 116 may terminate control of the processing to change the target resistance defined in the heating profile if the number of times that the target resistance defined in the heating profile has changed exceeds a predetermined threshold. Heater aging is thought to settle at the stage where it has progressed to a certain extent. In this regard, the configuration above makes it possible to omit various types of processing for updating the heating profile, such as measuring the initial resistance and monitoring changes over time in the duration of the Oth control period, after heater aging has settled. The processing load on the inhalation device 100 can be lessened as a result.
An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 12. Fig. 12 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 12, the control unit 116 first of all implements processing to set a reference value of the duration of the Oth control period (step S702). The processing relating to step S702 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the Oth control period which has been set (step S704). Step S702 includes steps S712-S716. Furthermore, step S704 includes steps S718-S730. The processing relating to steps S712-S728 is the same as the processing relating to steps S112-S128 described with reference to fig. 5 and will therefore not be described in detail. Step S730 will be described in detail below.
After step S728, the control unit 116 adds up the amount of change in the target resistance in step S728 each time step S728 is repeated, and determines whether or not the cumulative amount of change has exceeded a predetermined threshold (step S730). It should be noted that the control unit 116 may calculate the cumulative amount of change only for a specific target resistance, such as the target resistance in the first control period.
If it is determined that the cumulative amount of change in the target resistance has not exceeded the predetermined threshold (step S730: NO), then the processing returns to step S712.
If it is determined that the cumulative amount of change in the target resistance has exceeded the predetermined threshold (step S730: YES), then the processing ends.

(7) Seventh variant example

The control unit 116 may control the processing to change the target resistance defined in the heating profile, based on the change over time in the duration of the 0th control period which was acquired when heating was started within a predetermined time from the heating unit 121 ending the previous heating. The previous heating by the heating unit 121 as referred to here means heating based on the heating profile. The temperature of the accommodating portion 140 at the start of heating is lower than normal when smoking intervals are excessively spaced apart, and the effect thereof can make it difficult to appropriately determine changes over time in the duration of the 0th control period. In this regard, the configuration above enables changes over time in the duration of the 0th control period to be appropriately determined.
An example of the flow of processing implemented by means of the inhalation device 100 according to the variant example will be described below with reference to fig. 13. Fig. 13 is a flowchart showing an example of a flow of heating profile update processing implemented by the inhalation device 100 according to the variant example.
As shown in fig. 13, the control unit 116 first of all implements processing to set a reference value of the duration of the 0th control period (step S802)). The processing relating to step S802 is preferably omitted/implemented on the same basis as for the processing relating to step S102. Next, the control unit 116 implements the processing to update the heating profile based on the reference value of the duration of the 0th control period which has been set (step S804). Step S802 includes steps S812-S818. Furthermore, step S804 includes steps S820-S832. Each of these steps will be described in detail below.
As shown in fig. 13, the control unit 116 first of all implements heating based on the heating profile (step S812).
Next, the control unit 116 determines whether or not an interval of implementing heating based on the heating profile is less than 24 hours (step S814). To be more specific, the control unit 116 determines whether or not the time elapsed since the heating unit 121 previously ended heating based on the heating profile until the heating unit 121 starts heating based on the heating profile in step S812 is less than 24 hours.
If the interval of implementing heating based on the heating profile is judged to be equal to or greater than 24 hours (step S814: NO), then the processing returns to step S812.
On the other hand, if the interval of implementing heating based on the heating profile is judged to be less than 24 hours (step S814: YES), then the control unit 116 measures the duration of the 0th control period for the heating based on the heating profile implemented in step S812 (step S816).
The control unit 116 then causes the memory unit 114 to store the measured value of the duration of the 0th control period which was measured in step S816, as the reference value of the duration of the Oth control period (step S818).
After this, the control unit 116 implements heating based on the heating profile (step S820).
Next, the control unit 116 determines whether or not the interval of implementing heating based on the heating profile is less than 24 hours (step S822). To be more specific, the control unit 116 determines whether or not the time elapsed since the heating unit 121 previously ended heating based on the heating profile until the heating unit 121 starts heating based on the heating profile in step S820 is less than 24 hours.
If the interval of implementing heating based on the heating profile is judged to be equal to or greater than 24 hours (step S822: NO), then the processing returns to step S820.
On the other hand, if the interval of implementing heating based on the heating profile is judged to be less than 24 hours (step S822: YES), then the control unit 116 measures the duration of the 0th control period for the heating based on the heating profile implemented in step S820 (step S824).
Next, the control unit 116 calculates the difference between the measured value and the reference value of the duration of the Oth control period (step S826).
Next, the control unit 116 estimates the amount of change in the maximum temperature of the accommodating portion 140, based on the difference between the measured value and the reference value of the duration of the 0th control period (step S828).
Next, the control unit 116 determines whether or not the estimated amount of change in the maximum temperature of the accommodating portion 140 is equal to or greater than the heater aging determination threshold (step S830).
If the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be less than the heater aging determination threshold (step S830: NO), then the processing returns to step S820.
On the other hand, if the estimated amount of change in the maximum temperature of the accommodating portion 140 is judged to be equal to or greater than the heater aging determination threshold (step S830: YES), then the control unit 116 changes the target resistance defined in the heating profile in accordance with the estimated amount of change in the maximum temperature of the accommodating portion 140 (step S832).
After this, the processing returns to step S812.

4. Verification of effects

The present inventors carried out an experiment to verify the effects of the technology according to the present disclosure. Specifically, the present inventors reproduced heater aging by repeating a heater aging treatment multiple times, the heater aging treatment comprising increasing the temperature of the heating unit 121 to 320°C, then reducing the temperature to 260°C, and then cooling the heating unit 121. The present inventors then caused the inhalation device 100 to implement the processing to update the heating profile described above at the times when the number of cycles reached 2, 25, 50, 75, 100, 250, 500, 1000, 1500 and 2000. In this process, the present inventors reduced the target resistance value in the first control period by 5 mΩ when the estimated amount of change in the maximum temperature of the accommodating portion 140 was 5°C or greater. This experiment was carried out under an environment of 25°C. The results of the experiment will be described below with reference to fig. 14.
Fig. 14 is a graph showing the results of the experiment to verify the effects of the technology according to the present disclosure. The vertical axis of the graph 40 shown in fig. 14 denotes the actual maximum temperature of the accommodating portion 140 (which differs from the temperature estimated on the basis of the duration of the 0th control period). The horizontal axis of the graph 40 denotes the number of cycles.
Referring to the graph 40, the maximum temperature of the accommodating portion 140 increases rapidly from the time of 2 cycles up to the time of 50 cycles. To be more specific, the maximum temperature of the accommodating portion 140 is 318.5°C at the time of 2 cycles, 319.8°C at the time of 25 cycles, and 321.4°C at the time of 50 cycles. Here, the control unit 116 is using a default heating profile. The estimated amount of change in the maximum temperature of the accommodating portion 140 which was estimated on the basis of the duration of the 0th control period from the time of 2 cycles until the time of 50 cycles reached 5.1°C (the actual amount of change was 2.9°C), so the control unit 116 reduced the target resistance in the first control period by 5 mΩ. As a result, the duration of the Oth control period at the time of 51 cycles was shortened from the duration at 50 cycles, and the maximum temperature of the accommodating portion 140 was reduced by approximately 5°C to 316.5°C from the 321.4°C at the time of 50 cycles as a result.
Referring to the graph 40, the maximum temperature of the accommodating portion 140 increases while steadily losing strength from the time of 51 cycles up to the time of 250 cycles. To be more specific, the maximum temperature of the accommodating portion 140 is 316.5°C at the time of 51 cycles, 319.5°C at the time of 75 cycles, 320.6°C at the time of 100 cycles, and 321.5°C at the time of 250 cycles. Here, the control unit 116 is using a heating profile following the first update. The amount of change in the maximum temperature of the accommodating portion 140 which was estimated on the basis of the duration of the Oth control period from the time of 51 cycles until the time of 250 cycles reached 5.1°C (the actual amount of change was 5.0°C), so the control unit 116 reduced the target resistance in the first control period by 5 mΩ. As a result, the duration of the Oth control period at the time of 251 cycles was shortened from the duration at 250 cycles, and the maximum temperature of the accommodating portion 140 was reduced by approximately 5°C to 316.5°C from the 321.5°C at the time of 250 cycles as a result.
Referring to the graph 40, the maximum temperature of the accommodating portion 140 slowly increases while further losing strength from the time of 251 cycles up to the time of 2000 cycles. To be more specific, the maximum temperature of the accommodating portion 140 is 316.5°C at the time of 251 cycles, 317.8°C at the time of 500 cycles, 317.7°C at the time of 1000 cycles, 318.6°C at the time of 1500 cycles, and 318.8°C at the time of 2500 cycles. Here, the control unit 116 is using a heating profile following the second update.
As described above, the inhalation device 100 implements the processing to update the heating profile described above, and variations in the maximum temperature of the accommodating portion 140 are thereby suppressed. In particular, the extent of variation in the maximum temperature of the accommodating portion 140 can be kept at no greater than 5°C, as shown in the graph 40. By virtue of the technology according to the present disclosure, even if the heating characteristics of the inhalation device 100 change over time, the temperature transition of the accommodating portion 140 can thus be restored to the state before the change over time in the heating characteristics of the inhalation device 100. This makes it possible to suppress a deterioration in the quality of the user experience associated with changes over time in the heating characteristics of the inhalation device 100, making it possible to improve the quality of the user experience as a result.

5. 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 such 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 embodiment described above, the resistance of the heating unit 121 rises as the temperature of the heating unit 121 rises, but the present disclosure is not limited to this example. The resistance of the heating unit 121 may equally fall as the temperature of the heating unit 121 rises.
The embodiment above described an example in which the accommodating portion 140 functions as a heat transfer portion in an inhalation device 100 of the type in which the stick-type substrate 150 is heated from the outer periphery thereof, but the present disclosure is not limited to this example. For example, the heating unit 121 may be configured in the form of a blade. The blade-form heating unit 121 may be constructed by sandwiching a planar heating resistor between two metal plates corresponding to the heat transfer portion, and a pressure-sensitive adhesive layer may be provided between the heating resistor and the metal plates. In this configuration also, heater aging progresses because of degeneration of the pressure-sensitive adhesive layer, so it is desirable for the heating profile to be updated in the same way as in the embodiment described above.
Examples of devices classified as inhalation devices 100 that may be cited include those used in place of cigarettes, such as electronic cigarettes and heated tobacco, and also nebulizers, etc. used for medical purposes. It should be noted that an electronic cigarette is an inhalation device 100 of the type which generates an aerosol by heating, etc. and atomizing a liquid aerosol source. Heated tobacco is an inhalation device 100 of the type which generates an aerosol by heating a solid containing an aerosol source. The embodiment above described an example in which the inhalation device 100 is heated tobacco, but it may equally be an electronic cigarette or a nebulizer.
The embodiment above described an example in which a pressure-sensitive adhesive layer formed by a pressure-sensitive adhesive is provided between the heating unit 121 and the accommodating portion 140, but the present disclosure is not limited to this example. An adhesion layer formed by an adhesive may equally be provided between the heating unit 121 and the accommodating portion 140. It is desirable for the heating profile to be updated in the same way as in the embodiment described above when heater aging progresses because of degeneration of the adhesion layer. It should be noted that a pressure-sensitive adhesive is a material which maintains a wet state both before and after use. An adhesive on the other hand becomes solid after use.
The embodiment above described an example in which the target resistance in the 0th control period is set at 99.5% of the target resistance in the first control period, but the present disclosure is not limited to this example. The target resistance in the 0th control period should be set, based on the target resistance in the first control period, as a value at which the corresponding temperature of the heating unit 121 is lower than for the target resistance in the first control period.
The embodiment above described an example in which the duration of the Oth control period is utilized as an indicator to show progression of heater aging, but the present disclosure is not limited to this example. The number of times that heating based on the heating profile has been implemented or a cumulative heating time may be used instead as an indicator to show progression of heater aging. However, it can be said that the duration of the 0th control period most accurately represents the progression of heater aging, given that heating based on the heating profile may end partway through, or that the heating temperature fluctuates from time to time according to the heating profile.
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 random access memory (RAM) and executed by means of a processing circuit such as a central processing unit (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 (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 centrally by a single computer, or may be processed in a distributed manner by multiple computers. In addition, in the embodiments described above, two or more communication means present in a single device may be physically realized by a single medium.
Furthermore, the processing described using flowcharts or 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 heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source;
- a heating unit for heating the substrate through the heat transfer portion; and
- a control unit for controlling operation of the heating unit,
- wherein
- the control unit
- controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and
- controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.
(2) The aerosol-generating system as disclosed in (1) above, wherein the control unit
- calculates, as the change over time in the length of the control period, a difference between the length of the control period and a reference value of the length of the control period, and
- if the target value has been changed, changes the reference value based on the changed target value.
(3) The aerosol-generating system as disclosed in (1) or (2) above, wherein the control unit controls processing to change the target value defined in the control information, based on the parameter at a timing when the heating unit started heating.
(4) The aerosol-generating system as disclosed in (3) above, wherein the control unit corrects the length of the control period based on the parameter at the timing when the heating unit started heating, and controls the processing to change the target value defined in the control information, based on the post-correction length of the control period.
(5) The aerosol-generating system as disclosed in (3) or (4) above, wherein the control unit changes the target value defined in the control information only if the parameter at the timing when the heating unit started heating is included in a first range.
(6) The aerosol-generating system as disclosed in any one of (1) to (5) above, wherein the control unit changes the target value defined in the control information only if the length of the control period is included in a second range.
(7) The aerosol-generating system as disclosed in any one of (1) to (6) above, wherein the control unit terminates control of the processing to change the target value defined in the control information if a cumulative amount of change in the target value defined in the control information exceeds a predetermined threshold.
(8) The aerosol-generating system as disclosed in any one of (1) to (7) above, wherein the control unit changes the target value defined in the control information, based on the change over time in the length of the control period which was acquired when heating was started within a predetermined time from the heating unit ending the previous heating.
(9) The aerosol-generating system as disclosed in any one of (1) to (8) above, wherein the control unit controls the processing to change the target value defined in the control information, based on a change over time in a temperature transition of the heat transfer portion which is estimated on the basis of the change over time in the length of the control period.
(10) The aerosol-generating system as disclosed in (9) above, wherein the control unit changes the target value defined in the control information if the number of times that a change over time in the temperature of the heat transfer portion, which is estimated on the basis of the change over time in the length of the control period, satisfied a predetermined condition, reaches a first number of times, and
the first number of times is two or more.
(11) The aerosol-generating system as disclosed in (10) above, wherein the control unit changes the target value defined in the control information if the number of times that the change over time in the temperature of the heat transfer portion, which is estimated on the basis of the change over time in the length of the control period, continuously satisfied the predetermined condition, reaches a second number of times, and
the second number of times is two or more.
(12) The aerosol-generating system as disclosed in any one of (1) to (11) above, wherein the heating unit is laminated on the heat transfer portion with a pressure-sensitive adhesive layer interposed.
(13) The aerosol-generating system as disclosed in any one of (1) to (12) above, wherein the heat transfer portion is a cylindrical body having an opening into which the substrate is inserted, and
the heating unit is arranged on the outer periphery of the cylindrical body.
(14) A control method implemented by means of a computer for controlling an aerosol-generating system, wherein the aerosol-generating system comprises:
- a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; and
- a heating unit for heating the substrate through the heat transfer portion,
- and wherein
- the control method comprises
- controlling operation of the heating unit, and
- controlling operation of the heating unit comprises
- controlling operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and
- controlling processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.
(15) A program executed by means of a computer for controlling an aerosol-generating system, wherein
the aerosol-generating system comprises:
- a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; and
- a heating unit for heating the substrate through the heat transfer portion,
- and wherein
- the program causes the computer to function as
- a control unit for controlling operation of the heating unit, and
- the control unit
- controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and
- controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.

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
142 Opening
143 Bottom portion
144 Heat insulating portion
150 Stick-type substrate

Claims

An aerosol-generating system comprising: a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source;
a heating unit for heating the substrate through the heat transfer portion; and

a control unit for controlling operation of the heating unit,

wherein

the control unit

controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and

controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.
The aerosol-generating system as claimed in claim 1, wherein the control unit
calculates, as the change over time in the length of the control period, a difference between the length of the control period and a reference value of the length of the control period, and

if the target value has been changed, changes the reference value based on the changed target value.
The aerosol-generating system as claimed in claim 1 or 2, wherein the control unit controls processing to change the target value defined in the control information, based on the parameter at a timing when the heating unit started heating.
The aerosol-generating system as claimed in claim 3, wherein the control unit corrects the length of the control period based on the parameter at the timing when the heating unit started heating, and controls the processing to change the target value defined in the control information, based on the post-correction length of the control period.
The aerosol-generating system as claimed in claim 3 or 4, wherein the control unit changes the target value defined in the control information only if the parameter at the timing when the heating unit started heating is included in a first range.
The aerosol-generating system as claimed in any one of claims 1 to 5, wherein the control unit changes the target value defined in the control information only if the length of the control period is included in a second range.
The aerosol-generating system as claimed in any one of claims 1 to 6, wherein the control unit terminates control of the processing to change the target value defined in the control information if a cumulative amount of change in the target value defined in the control information exceeds a predetermined threshold.
The aerosol-generating system as claimed in any one of claims 1 to 7, wherein the control unit changes the target value defined in the control information, based on the change over time in the length of the control period which was acquired when heating was started within a predetermined time from the heating unit ending the previous heating.
The aerosol-generating system as claimed in any one of claims 1 to 8, wherein the control unit controls the processing to change the target value defined in the control information, based on a change over time in a temperature transition of the heat transfer portion which is estimated on the basis of the change over time in the length of the control period.
The aerosol-generating system as claimed in claim 9, wherein the control unit changes the target value defined in the control information if the number of times that a change over time in the temperature of the heat transfer portion, which is estimated on the basis of the change over time in the length of the control period, satisfied a predetermined condition, reaches a first number of times, and
the first number of times is two or more.
The aerosol-generating system as claimed in claim 10, wherein the control unit changes the target value defined in the control information if the number of times that the change over time in the temperature of the heat transfer portion, which is estimated on the basis of the change over time in the length of the control period, continuously satisfied the predetermined condition, reaches a second number of times, and
the second number of times is two or more.
The aerosol-generating system as claimed in any one of claims 1 to 11, wherein the heating unit is laminated on the heat transfer portion with a pressure-sensitive adhesive layer interposed.
The aerosol-generating system as claimed in any one of claims 1 to 12, wherein the heat transfer portion is a cylindrical body having an opening into which the substrate is inserted, and
the heating unit is arranged on the outer periphery of the cylindrical body.
A control method implemented by means of a computer for controlling an aerosol-generating system, wherein the aerosol-generating system comprises:
a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; and

a heating unit for heating the substrate through the heat transfer portion,

and wherein

the control method comprises

controlling operation of the heating unit, and

controlling operation of the heating unit comprises

controlling operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and

controlling processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.
A program executed by means of a computer for controlling an aerosol-generating system, wherein
the aerosol-generating system comprises:
a heat transfer portion arranged to be capable of contacting a substrate containing an aerosol source; and

a heating unit for heating the substrate through the heat transfer portion,

and wherein

the program causes the computer to function as

a control unit for controlling operation of the heating unit, and

the control unit

controls operation of the heating unit based on control information defining a target value of a parameter corresponding to a temperature of the heating unit, and

controls processing to change the target value defined in the control information, based on a change over time in the length of a control period from the start of heating by the heating unit until the parameter reaches a specific target value.