Patent Description:
Recently, the demand for alternative methods of overcoming the shortcomings of general cigarettes has increased. For example, there is growing demand for a method of generating aerosol by heating an aerosol generating material in cigarettes, rather than by burning cigarettes.

In addition to an internal heating method and an external heating method, an induction heating method using a coil and a susceptor is used to heat an aerosol generating material. In the case of the induction heating method, when an alternating current voltage is applied to a coil, a magnetic field is generated, and a temperature of a heater (or a susceptor) is increased by the magnetic field. As an aerosol generating material is heated by the heater, an aerosol is generated. <CIT> relates to an inductive heating device that comprises: a device housing, a DC power source, a power supply electronics comprising a DC/AC inverter comprising a Class-E power amplifier with a transistor switch, a transistor switch driver circuit, and an LC circuit configured to operate at low ohmic load, the LC circuit comprising a series connection of a single inductor and a single capacitor, and a cavity arranged in the device housing, the cavity having an internal surface shaped to accommodate at least a portion of the aerosol-forming substrate, wherein the cavity is arranged such that the single inductor is inductively coupled to the susceptor of the aerosol-forming substrate during operation. <CIT> relates to a method and apparatus for use with an RLC resonance circuit for inductive heating of a susceptor of an aerosol generating device. The apparatus is arranged to determine a resonant frequency of the RLC resonance circuit; and determine, based on the determined resonant frequency, a first frequency for the RLC resonance circuit for causing the susceptor to be inductively heated, the first frequency being above or below the determined resonant frequency. The apparatus may be arranged to control a drive frequency of the RLC resonance circuit to be at the determined first frequency in order to heat the susceptor. <CIT> relates to a circuitry for an induction element for an aerosol generating device. The induction element is for inductive heating of a susceptor for heating an aerosol generating material in use. The circuitry comprises a driver arrangement arranged to provide, from an input direct current, an alternating current for driving the induction element in use. The driver arrangement comprises a plurality of transistors Q1-<NUM> arranged in a H-bridge configuration. The H-bridge configuration comprises a high side pair of transistors and a low side pair of transistors, the high side pair being for connection to a first electric potential higher than a second electric potential to which the low side pair is for connection is use. At least one of the high side pair of transistors is a p-channel field effect transistor. <CIT> relates to an inductive heating assembly for generating an aerosol from an aerosol precursor material in an aerosol provision system, the inductive heating assembly comprising: a susceptor; and a drive coil arranged to induce current flow in the susceptor to heat the susceptor and vaporise aerosol precursor material in proximity with a surface of the susceptor, and wherein the susceptor comprises regions of different susceptibility to induced current flow from the drive coil, such that when in use the surface of the susceptor in the regions of different susceptibility are heated to different temperatures by the current flow induced by the drive coil.

A memory of an aerosol generating device stores a resonance frequency corresponding to a design standard of a coil. However, although a coil is made of the same standard and material, resistance deviation may occur in a production and assembly process, and thus, a resonance frequency may vary. Therefore, an actual heating temperature of a susceptor in the aerosol generating device may become different from a target temperature profile. One or more embodiments include an aerosol generating system capable of heating a susceptor according to a target temperature profile even when resistance deviation of a coil occurs. The technical problems to be achieved by one or more embodiments are not limited to the technical problems as described above, and other technical problems may be inferred from the following embodiments.

According to one or more embodiments, an aerosol generating device includes: a susceptor heating an aerosol generating article; a coil surrounding the susceptor and heating the susceptor by generating a magnetic field when an alternating current voltage is applied; and a controller electrically connected to the coil, wherein the controller applies a test voltage to the coil in response to a user input, measures an output current of the coil while changing a frequency of the test voltage, determines a frequency at which the output current becomes maximum, and applies an operating voltage having the determined frequency to the coil.

In one or more embodiments, a susceptor may be heated according to a target temperature profile by determining a resonance frequency for a coil and applying an operating voltage having the determined resonance frequency to the coil. Accordingly, even if a resonance frequency of a coil is different from the design standard due to resistance deviation occurring in a production and assembly process, an optimal smoking experience may be provided to a user in the same way as when a coil according to the design standard is used.

In an aerosol generating device according to the claimed invention, the controller determines the frequency at which the output current becomes maximum within a preset range by changing the frequency of the test voltage within the preset range.

The controller may receive a direct current (DC) voltage from a battery and thus generate a pulse width modulation (PWM) signal of the DC voltage, convert the PWM signal into the test voltage that is an alternating current (AC) voltage, and apply the test voltage to the coil.

The aerosol generating device may further include a feedback circuit, wherein the controller receives, through the feedback circuit, an output current of the coil which changes as a frequency of the test voltage changes and determines a frequency at which the output current becomes maximum by measuring the received output current.

The controller may, in a test mode, determine a frequency at which the output current becomes maximum by changing a frequency of a test voltage applied to the coil; enter a heating mode from the test mode after the frequency at which the output current becomes maximum is determined; and in the heating mode, apply the operating voltage having the determined frequency to the coil such that the susceptor is heated according to a target temperature profile.

In an aerosol generating device according to the claimed invention, the controller, when a maximum value of the output current measured within the preset range is less than a preset reference value, determines that the coil is abnormal and does not supply power to the coil.

According to one or more embodiments, an aerosol generating system includes: a memory; a cavity accommodating at least a portion of a cigarette; a coil located around the cavity; a susceptor heated by the coil; and a controller electrically connected to the coil, wherein the controller measures an output current of the coil while changing a frequency of a test voltage applied to the coil; stores, in the memory, a frequency at which the output current of the coil becomes maximum; and starts heating of the susceptor by applying an operating voltage having the stored frequency to the coil.

The aerosol generating system may further include a cigarette, wherein the cigarette includes: a nicotine transfer unit heated by the susceptor; a nicotine generator connected to a downstream end of the nicotine transfer unit and heated by the susceptor; and a filter unit connected to a downstream end of the nicotine generator.

In an aerosol generating system according to the present invention, the controller determines the frequency at which the output current becomes maximum by changing the frequency of the test voltage within a preset range, and store the determined frequency in the memory.

The controller may, after the frequency at which the output current of the coil becomes maximum is stored in the memory, in response to a user input for heating the susceptor, apply the operating voltage to the coil without applying the test voltage to the coil.

In an aerosol generating system according to the present invention, the controller, when a maximum value of the output current measured within the preset range is less than a preset reference value, determines that the coil is abnormal and does not supply power to the coil.

In addition, in certain cases, a term which is not commonly used may be selected.

Hereinafter, one or more embodiments will be described in detail with reference to the accompanying drawings.

<FIG> is a diagram showing an example in which an aerosol generating article is inserted into an inside-heating aerosol generating device. <FIG> is a diagram showing an example in which an aerosol generating article is inserted into an outside-heating aerosol generating device. <FIG> is a diagram showing another example in which an aerosol generating article is inserted into an outside-heating aerosol generating device. Hereinafter, one or more embodiments will be described in detail with reference to <FIG>.

Referring to <FIG>, the aerosol generating device <NUM> may include a battery <NUM>, a controller <NUM>, and a heater <NUM>. Referring to <FIG>, the aerosol generating device <NUM> may further include a vaporizer <NUM>. Also, the aerosol generating article <NUM> (e.g., a cigarette) may be inserted into an inner space of the aerosol generating device <NUM>.

Also, <FIG> illustrate that the aerosol generating device <NUM> includes the heater <NUM>. However, as necessary, the heater <NUM> may be omitted.

When the cigarette <NUM> is inserted into the aerosol generating device <NUM>, the aerosol generating device <NUM> may operate the heater <NUM> and/or the vaporizer <NUM> to generate an aerosol. The aerosol generated by the heater <NUM> and/or the vaporizer <NUM> is delivered to a user by passing through the cigarette <NUM>.

As necessary, even when the cigarette <NUM> is not inserted into the aerosol generating device <NUM>, the aerosol generating device <NUM> may heat the heater <NUM>.

In detail, the heater <NUM> may include a coil for heating a cigarette in an induction heating method, and the cigarette may include a susceptor which may be heated by the induction heater.

The vaporizer <NUM> may generate an aerosol by heating a liquid composition and the generated aerosol may pass through the cigarette <NUM> to be delivered to a user. In other words, the aerosol generated via the vaporizer <NUM> may move along an air flow passage of the aerosol generating device <NUM> and the air flow passage may be configured such that the aerosol generated via the vaporizer <NUM> passes through the cigarette <NUM> to be delivered to the user.

The aerosol generating device <NUM> may further include general-purpose components in addition to the battery <NUM>, the controller <NUM>, the heater <NUM>, and the vaporizer <NUM>. For example, the aerosol generating device <NUM> may include a display capable of outputting visual information and/or a motor for outputting haptic information. Also, the aerosol generating device <NUM> may include at least one sensor (e.g., a puff detecting sensor, a temperature detecting sensor, a cigarette insertion detecting sensor, etc.). Also, the aerosol generating device <NUM> may be formed as a structure where, even when the cigarette <NUM> is inserted into the aerosol generating device <NUM>, external air may be introduced or internal air may be discharged.

The cigarette <NUM> may be similar as a general combustive cigarette. For example, the cigarette <NUM> may be divided into a first portion <NUM> including an aerosol generating material and a second portion <NUM> including a filter, etc. Alternatively, the second portion <NUM> of the cigarette <NUM> may also include an aerosol generating material. For example, an aerosol generating material made in the form of granules or capsules may be inserted into the second portion <NUM>.

The entire first portion 21may be inserted into the aerosol generating device <NUM>, and the second portion <NUM> may be exposed to the outside. Alternatively, only a portion of the first portion <NUM> may be inserted into the aerosol generating device <NUM>. In an embodiment, the entire first portion <NUM> and a portion of the second portion <NUM> may be inserted into the aerosol generating device <NUM>. In this case, the aerosol is generated by the external air passing through the first portion <NUM>, and the generated aerosol passes through the second portion <NUM> and is delivered to the user's mouth.

For example, the external air may flow into at least one air passage formed in the aerosol generating device <NUM>. For example, the opening and closing and/or a size of the air passage formed in the aerosol generating device <NUM> may be adjusted by the user. Accordingly, the amount and quality of the aerosol may be adjusted by the user. As another example, the external air may flow into the cigarette <NUM> through at least one hole formed in a surface of the cigarette <NUM>.

<FIG> is an RLC circuit diagram and a graph showing power transmitted to a load according to the frequency of a current flowing through the circuit.

A coil may be supplied with an alternating current from a battery. A magnetic field is generated by the coil that is supplied with the alternating current from the battery. As the magnetic field generated by the coil passes through a load (e.g., a susceptor), the load may be heated.

Referring to <FIG>, the coil may be represented by an RLC circuit <NUM>. The RLC circuit <NUM> includes inductance L, resistance R, and capacitance C. Total impedance Z TOTAL of the RLC circuit <NUM> is calculated as a sum of impedance ZL of the inductance L, impedance ZR of the resistance R, and impedance ZC of the capacitance C.

The impedance ZL of the inductance L, the impedance ZR of the resistance R, and the impedance ZC of the capacitance C may be respectively expressed as in Equation <NUM> below.

Resonance refers to a phenomenon in which as a vibration system periodically receives an external force having the same frequency as a natural frequency thereof, the amplitude increases significantly. The resonance is a phenomenon that occurs in all vibrations, such as mechanical and electrical vibrations. In general, when a force for vibrating the vibration system is applied to the vibration system from the outside, and the natural frequency of the vibration system is the same as a frequency of the force applied from the outside, the vibration becomes severe, and the amplitude increases.

Similarly, when a plurality of vibrating bodies which are separated within a preset distance vibrate at the same frequency, the plurality of vibrating bodies resonate with each other. In this case, resistance is reduced between the plurality of vibrating bodies.

A resonant frequency freso of the RLC circuit <NUM> may be determined by, for example, Equation <NUM> below.

Referring to a graph <NUM> of <FIG>, when an alternating current having the resonant frequency freso is applied to the RLC circuit <NUM>, maximum power may be transmitted to a load (e.g., a susceptor). As a frequency of an alternating current applied to the RLC circuit <NUM> is different from the resonant frequency freso, a power value transmitted to the load decreases.

Referring to Equation <NUM> above, the resonant frequency freso of the RLC circuit <NUM> is determined by the inductance L and the capacitance C of the coil. In a circuit forming a magnetic field by using a coil, inductance L may be determined by the number of windings of the coil and the like, and capacitance C may be determined by a distance, an area, and the like between the windings of the coil.

<FIG> is an example of an aerosol generating system using an induction heating method.

Referring to <FIG>, an aerosol generating device <NUM> includes a battery <NUM>, a controller <NUM>, a coil <NUM>, and a susceptor <NUM>. A cavity <NUM> of the aerosol generating device <NUM> may accommodate at least a portion of a cigarette <NUM>.

The aerosol generating device <NUM> illustrated in <FIG> shows elements related to the present embodiment. Therefore, it will be understood by one of ordinary skill in the art related to the present embodiment that the aerosol generating device <NUM> may further include other general-purpose elements in addition to the elements illustrated in <FIG>.

The coil <NUM> may be located around the cavity <NUM>. <FIG> illustrates that the coil <NUM> is arranged to surround the cavity <NUM>, but it is not limited thereto.

When the cigarette <NUM> is accommodated in the cavity <NUM> of the aerosol generating device <NUM>, the aerosol generating device <NUM> may supply power to the coil <NUM> such that the coil <NUM> may generate a magnetic field. As the magnetic field generated by the coil <NUM> passes through the susceptor <NUM>, the susceptor <NUM> may be heated.

This induction heating phenomenon is a known phenomenon that can be explained by Faraday's Law of induction. In detail, when magnetic induction in the susceptor <NUM> changes, an electric field is generated in the susceptor <NUM>, and thus, an eddy current flows in the susceptor <NUM>. The eddy current generates, in the susceptor <NUM>, heat that is proportional to current density and conductor resistance.

As the susceptor <NUM> is heated by the eddy current and an aerosol generating material in the cigarette <NUM> is heated by the susceptor <NUM> that is heated, the aerosol may be generated. The aerosol generated from the aerosol generating material passes through the cigarette <NUM> and is delivered to a user.

The battery <NUM> supplies power to be used for the aerosol generating device <NUM> to operate. For example, the battery <NUM> may supply power such that the coil <NUM> may generate a magnetic field and may supply power needed for operating the controller <NUM>. Also, the battery <NUM> may supply power needed for operating a display, a sensor, a motor, and the like installed in the aerosol generating device <NUM>.

The controller <NUM> controls an overall operation of the aerosol generating device <NUM>. The controller <NUM> may be electrically connected to the coil <NUM>. In detail, the controller <NUM> controls operations of other elements included in the aerosol generating device <NUM>, as well as operations of the battery <NUM> and the coil <NUM>. Also, the controller <NUM> may determine whether or not the aerosol generating device <NUM> is in an operable state by checking states of respective elements of the aerosol generating device <NUM>.

The coil <NUM> may be an electrically conductive coil that generates a magnetic field by power supplied from the battery <NUM>. The coil <NUM> may be arranged to surround at least a portion of the cavity <NUM>. The magnetic field generated by the coil <NUM> may be applied to the susceptor <NUM> arranged at an inner end of the cavity <NUM>.

The susceptor <NUM> may be heated as the magnetic field generated from the coil <NUM> passes through the susceptor <NUM> and may include metal or carbon. For example, the susceptor <NUM> may include at least one of ferrite, a ferromagnetic alloy, stainless steel, and aluminum.

Also, the susceptor <NUM> may include at least one of graphite, molybdenum, silicon carbide, niobium, a nickel alloy, a metal film, ceramic such as zirconia, transition metal such as nickel (Ni) cobalt (Co), and metalloid such as boron (B) and phosphorus (P). However, the susceptor <NUM> is not limited to the example described above and may include all susceptors that may be heated to a wanted temperature as a magnetic field is applied thereto. Here, the wanted temperature may be preset in the aerosol generating device <NUM> or may be set to a temperature wanted by a user.

When the cigarette <NUM> is accommodated in the cavity <NUM> of the aerosol generating device <NUM>, the susceptor <NUM> may be arranged to surround at least a portion of the cigarette <NUM>. Therefore, the heated susceptor <NUM> may raise a temperature of the aerosol generating material in the cigarette <NUM>.

<FIG> illustrates that the susceptor <NUM> is arranged to surround at least a portion of the cigarette <NUM>, but the arrangement of the susceptor <NUM> is not limited thereto. For example, the susceptor <NUM> may include a tube-type heating element, a plate-type heating element, a needle-type heating element or a rod-type heating element and may heat an inside and/or an outside of the cigarette <NUM> according to a shape of a heating element.

Also, the aerosol generating device <NUM> may also include a plurality of susceptors <NUM> arranged therein. Here, the plurality of susceptors <NUM> may be arranged to be inserted into the cigarette <NUM> or may be arranged outside the cigarette <NUM>. Also, some of the plurality of susceptors <NUM> may be arranged to be inserted into the cigarette <NUM>, and the others may be arranged outside the cigarette <NUM>. In addition, the shape of the susceptor <NUM> is not limited to the shape illustrated in <FIG> and may be formed in various shapes.

<FIG> is a block diagram illustrating a hardware configuration of an aerosol generating device according to an embodiment.

Referring to <FIG>, an aerosol generating device <NUM> may include a battery <NUM>, a controller <NUM>, a coil <NUM>, a susceptor <NUM>, a feedback circuit <NUM>, and a memory <NUM>.

The battery <NUM> is a direct current power source and supplies a direct current (DC) voltage to the controller <NUM> for an operation of the aerosol generating device <NUM>. In an embodiment, a regulator for keeping a voltage of the battery <NUM> constant may be included between the battery <NUM> and the controller <NUM>.

The controller <NUM> may include a microcontroller unit (MCU) <NUM> and an inverter circuit <NUM>. The inverter circuit <NUM> may include an amplifier (Amp) <NUM> and a field effect transistor (FET) <NUM>. However, it will be understood by one of ordinary skill in the art related to the present embodiment that other components may be further included, in addition to the components illustrated in <FIG>.

The controller <NUM> may receive a DC voltage from the battery <NUM>, generate a control signal, and transmit the generated control signal to another component of the aerosol generating device <NUM>. The controller <NUM> may collectively control the battery <NUM>, the coil <NUM>, the feedback circuit <NUM>, and the memory <NUM> by using the control signal.

The MCU <NUM> is supplied with a DC voltage from the battery <NUM> to generate a pulse width modulation (PWM) signal. The MCU <NUM> changes a frequency of the PWM signal within a preset range and transmits the PWM signal to the inverter circuit <NUM>. In detail, the MCU <NUM> includes two ports, and each of the two ports transmits a PWM signal of the same waveform to the inverter circuit <NUM>. According to an embodiment, a PWM signal output from the MCU <NUM> may be a digital PWM signal.

The inverter circuit <NUM> may convert a PWM signal of a DC voltage received from the MCU <NUM> into an alternating current (AC) voltage. The inverter circuit <NUM> may receive two PW signals of the same waveform from the MCU <NUM> and perform logic operation and amplification for converting the two PWM signals into an AC voltage. The inverter circuit <NUM> may apply an AC voltage to the coil <NUM>.

When the AC voltage is applied from the inverter circuit <NUM> to the coil <NUM>, the coil <NUM> generates a magnetic field. The frequency of the AC voltage transmitted from the inverter <NUM> to the coil <NUM> may be determined according to a frequency of a PWM signal transmitted from the MCU <NUM> to the inverter circuit <NUM>. In other words, as a frequency of a PWM signal generated from the MCU <NUM> is changed, a frequency of an AC voltage applied to the coil <NUM> is accordingly changed.

In detail, the inverter circuit <NUM> may include the Amp <NUM> and the FET <NUM>. The Amp <NUM> may be implemented as an array of a plurality of logic gates. The Amp <NUM> may receive PWM signals generated from the two ports of the MCU <NUM> and perform logic operation by using the plurality of logic gates. Also, the Amp <NUM> may amplify the PWM signals received from the MCU <NUM> according to a preset amplification factor. The Amp <NUM> may perform logic operation and amplification on the PWM signals and transmit the PWM signals to the FET <NUM>. The logic operation and amplification on the PWM signals may be performed by the Amp <NUM> so that the PWM signals are converted into an AC voltage in the FET <NUM>.

The FET <NUM> may convert the PWM signals received from the Amp <NUM> into the AC voltage and transmit the AC voltage to the coil <NUM>. The FET <NUM> may be opened and closed according to a PWM signal or a timer. According to one or more embodiments, the FET <NUM> may be replaced with a switch.

The coil <NUM> may receive the AC voltage from the controller <NUM>. When the AC voltage is applied from the controller <NUM> to the coil <NUM>, the coil <NUM> may generate a magnetic field. The strength of the magnetic field generated by the coil <NUM> may vary according to resistance or the like of the coil <NUM>.

The susceptor <NUM> may be located inside the coil <NUM>. The susceptor <NUM> may heat an aerosol generating article by generating heat within the magnetic field generated from the coil <NUM>. The heat generated by the susceptor <NUM> may vary according to the strength of the magnetic field generated by the coil <NUM>.

The feedback circuit <NUM> may transmit, to the MCU <NUM>, an output current flowing through the coil <NUM>. As a frequency of the AC voltage applied to the coil <NUM> is changed, the output current flowing through the coil <NUM> varies. In other words, the feedback circuit <NUM> may measure the output current of the coil <NUM> that continuously varies as the frequency of the AC voltage applied to the coil <NUM> changes, and transmit the measured output current to the MCU <NUM>.

The MCU <NUM> may determine a frequency of the AC voltage applied to the coil <NUM> when the output current of the coil <NUM> received from the feedback circuit <NUM> becomes maximum. The MUC <NUM> may enable the susceptor <NUM> to be heated by generating a PWM signal having the determined frequency. The determined frequency may be a resonance frequency of the coil <NUM>.

The memory <NUM> is hardware storing various types of data processed by the aerosol generating device <NUM>. The memory <NUM> may store pieces of data processed by the controller <NUM> and pieces of data to be processed by the controller <NUM>. The memory <NUM> may be implemented as various types such as random access memory (RAM) such as dynamic random access memory (DRAM) and static random access memory (SRAM), read-only memory (ROM), and electrically erasable programmable read-only memory.

The memory <NUM> may store data regarding an operation time of the aerosol generating device <NUM>, at least one temperature profile, at least one power profile, a smoking pattern of a user, and the like. Also, the memory <NUM> may store information regarding a resonance frequency of the coil <NUM> determined by the controller <NUM>. The information regarding the resonance frequency of the coil <NUM> stored in the memory <NUM> may be used to heat the susceptor <NUM>.

In an embodiment, the aerosol generating device <NUM> may have a plurality of modes. For example, a mode of the aerosol generating device <NUM> may include a sleep mode, a test mode, and a heating mode. However, the mode of the aerosol generating device <NUM> is not limited thereto.

When the aerosol generating device <NUM> is not used, the aerosol generating device <NUM> may maintain the sleep mode. In the sleep mode, the controller <NUM> may control an output voltage of the battery <NUM> so that power is not supplied to the coil <NUM>. For example, before or after the use of the aerosol generating device <NUM>, the aerosol generating device <NUM> may enter the sleep mode.

In response to a user input to the aerosol generating device <NUM>, the controller <NUM> may set the mode of the aerosol generating device <NUM> to the test mode (or may switch the mode from the sleep mode to the test mode). In the test mode, the controller <NUM> may determine a resonance frequency corresponding to the coil <NUM> by changing a frequency of a test voltage applied to the coil <NUM>. The test voltage is an AC voltage applied to the coil <NUM> in the test mode. The test voltage is a voltage applied to the coil <NUM> to determine a resonance frequency and is different from an operating voltage used to heat the susceptor <NUM> in the heating mode.

Also, after the resonance frequency is determined, the controller <NUM> may switch the mode of the aerosol generating device <NUM> from the test mode to the heating mode. In the heating mode, the controller <NUM> starts heating of the susceptor <NUM> by applying an operating voltage having the resonance frequency determined in the test mode. The operating voltage is an AC voltage applied to the coil <NUM> that is used in the heating mode. As the operating voltage having the resonance frequency is applied to the coil <NUM>, the susceptor <NUM> may be heated according to a target temperature profile in the heating mode.

A temperature profile indicates a change in temperature of the susceptor <NUM> over time and may provide an optimal smoking experience to a user when the susceptor <NUM> is heated according to the target temperature profile.

In another embodiment, the aerosol generating device <NUM> may determine whether or not the aerosol generating device <NUM> is to enter the test mode, according to an input of the user. When an input of the user for determining a resonance frequency of the coil <NUM> is received, the aerosol generating device <NUM> may determine the resonance frequency by entering the test mode from the sleep mode and start heating of the susceptor <NUM> by entering the heating mode from the test mode.

When an input of the user for heating the susceptor <NUM> is received after information regarding the resonance frequency is stored in the memory <NUM>, the aerosol generating device <NUM> may omit to enter the test mode, enter the heating mode from the sleep mode, and apply, to the coil <NUM>, an operating voltage having the resonance frequency stored in the memory <NUM>, thereby starting heating of the susceptor <NUM>.

In another embodiment, the test mode may be executed in an inspection process of inspecting an error in manufacturing of the coil <NUM> before the aerosol generating device <NUM> is distributed to the user. In the inspection process of the aerosol generating device <NUM>, the aerosol generating device <NUM> may enter the test mode, and a resonance frequency determined in the inspection process may be stored in the memory <NUM>.

After the aerosol generating device <NUM> is distributed to the user, the aerosol generating device <NUM> may be immediately switched from the sleep mode to the heating mode without undergoing the test mode. In the heating mode, as an operating voltage having the resonance frequency determined in the inspection process is applied to the coil <NUM>, heating of the susceptor <NUM> may start.

However, descriptions of an input method and an input subject for execution of the test mode are not limited to the examples described above, and various modifications and equivalent other embodiments may be made therefrom.

<FIG> is a view illustrating an example of a cigarette according to an embodiment.

Referring to <FIG>, a cigarette <NUM> includes a nicotine transfer unit <NUM>, a nicotine generator <NUM>, and a filter unit. The filter unit includes a cooling unit <NUM> and a mouth filter <NUM>. As needed, the filter unit may further include a segment performing another function.

The nicotine transfer unit <NUM> includes an aerosol generating material. The nicotine transfer unit <NUM> may include at least one of glycerin, propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and oleyl alcohol but is not limited thereto. The nicotine transfer unit e710 may be heated such that an aerosol may be generated.

The nicotine generator <NUM> includes a tobacco material including nicotine. The nicotine generator <NUM> may include a tobacco material such as tobacco leaves, a reconstituted tobacco, and tobacco granules. The nicotine generator <NUM> may be formed as a sheet, strands, or shredded tobacco which is formed of tiny bits cut from a tobacco sheet.

The cooling unit <NUM> cools an aerosol generated by heating at least one of the nicotine transfer unit <NUM> and the nicotine generator <NUM>. Therefore, a user may puff the aerosol cooled at an appropriate temperature.

The mouth filter <NUM> may be a cellulose acetate filter.

The mouth filter <NUM> may be a cylindrical type or a tube type having a hollow inside. Also, the mouth filter <NUM> may be a recessed type.

The aerosol generated by the nicotine transfer unit <NUM> and the nicotine generator <NUM> is cooled by passing through the cooling unit <NUM>, and the cooled aerosol is delivered to the user through the mouth filter <NUM>. Therefore, when a flavoring element is added to the mouth filter <NUM>, the persistence of flavors delivered to the user may be enhanced.

Although not illustrated in <FIG>, the cigarette <NUM> may be packaged by at least one wrapper. The wrapper may have at least one hole through which external air may be introduced or internal air may be discharged. As an example, the cigarette <NUM> may be packaged by one wrapper. As another example, the cigarette <NUM> may be double-packaged by two or more wrappers.

<FIG> is a view illustrating an example of an aerosol generating system in which a cigarette is inserted.

The aerosol generating system includes an aerosol generating device <NUM> and a cigarette <NUM>.

The aerosol generating device <NUM> may include a battery <NUM>, a controller <NUM>, a coil <NUM>, a susceptor, and a cavity <NUM>. The cigarette <NUM> may include a nicotine transfer unit <NUM>, a nicotine generator <NUM>, a cooling unit <NUM>, and a mouth filter <NUM>. However, it will be understood by one of ordinary skill in the art related to the present embodiment that other elements may be further included in addition to the elements illustrated in <FIG>.

The susceptor <NUM> may be part of the aerosol generating device <NUM>. The susceptor <NUM> may extend in a longitudinal direction of the cavity <NUM> along an inner wall <NUM> forming the cavity <NUM>.

The cigarette <NUM> may include the nicotine transfer unit <NUM> and the nicotine generator <NUM> connected to a downstream end of the nicotine transfer unit <NUM>.

The nicotine transfer unit <NUM> includes a moisturizer (e.g., glycerin, propylene glycol, or the like), and an aerosol (atomization) is generated as the nicotine transfer unit <NUM> is heated. The nicotine generator <NUM> includes a tobacco material (e.g., tobacco leaves, a reconstituted tobacco, tobacco granules, or the like) including nicotine, and nicotine is generated as the nicotine generator <NUM> is heated.

When a cigarette <NUM> is accommodated in the cavity <NUM> of the aerosol generating device <NUM>, the susceptor <NUM> may be located to surround an outside of the cigarette <NUM>. Here, the susceptor <NUM> may be located at a position corresponding to a transfer unit <NUM> and a nicotine generator <NUM>.

The susceptor <NUM> may be part of the cigarette <NUM>. The susceptor <NUM> may be located on an outer surface of the cigarette <NUM> to extend along a longitudinal direction of the cigarette <NUM>. Also, the susceptor <NUM> may be packaged by at least one wrapper.

When the cigarette <NUM> is accommodated in the cavity <NUM> of the aerosol generating device <NUM>, the aerosol generating device <NUM> may supply power to the coil <NUM> such that the coil <NUM> may generate a magnetic field. As the magnetic field generated by the coil <NUM> and the coil <NUM> passes through the susceptor <NUM>, the susceptor <NUM> may heat the nicotine transfer unit <NUM> and the nicotine generator <NUM>.

In another embodiment, the susceptor <NUM> may include a first portion 810a of a susceptor and a second portion 810b of the susceptor. Here, a first portion 810a of the susceptor may be located at a position corresponding to a transfer unit <NUM>, and a second portion 810b of the susceptor may be located at a position corresponding to a nicotine generator <NUM>.

Since materials included in the nicotine transfer unit <NUM> and the nicotine generator <NUM> are different, heating temperatures of the nicotine transfer unit <NUM> and the nicotine generator <NUM> for proving a user with a best tobacco taste may be different.

To heat the nicotine transfer unit <NUM> and the nicotine generator <NUM> at different temperatures, heating temperatures of the first portion 810a of the susceptor and the second susceptor 810b of the susceptor may be different. In other words, since the first portion 810a of the susceptor heats the nicotine transfer unit <NUM>, and the second portion 810b of the susceptor heats the nicotine generator <NUM>, heating temperatures of the nicotine transfer unit <NUM> and the nicotine generator <NUM> become different.

When the first portion 810a of the susceptor and the second portion 810b of the susceptor are part of the cigarette <NUM>, the first portion 810a of the susceptor and the second portion 810b of the susceptor may be connected to each other to form a single heating body or may be separated from each other to be respectively located at positions corresponding to the nicotine transfer unit <NUM> and the nicotine generator <NUM>.

<FIG> is an example of a graph illustrating a change in a resonance frequency according to resistance deviation of a coil.

Referring to a graph <NUM> for a coil having resistance according to a design standard, the coil has a resonance frequency f1. Referring to a graph <NUM> for a coil in which resistance deviation has occurred in a production and assembly process, the coil has a resonance frequency f2.

When f1, which is a resonance frequency according to a design standard, is applied to the coil for the graph <NUM> and the coil for the graph <NUM>, the coil for the graph <NUM> may resonate and a maximum output current I1 may flow through the coil for the graph <NUM>. However, because f1 does not correspond to a resonance frequency of the coil for the graph <NUM>, an output current I2 that is lower than the maximum output current I1 may flow through the coil for the graph <NUM>. Accordingly, when an AC voltage having a preset frequency (e.g., f1) is applied to a coil with resistance deviation, a susceptor may not be controlled according to a target temperature profile unless the frequency is adjusted.

In other words, when the susceptor is heated by applying the AC voltage to the coil, a frequency of the AC voltage applied to the coil may be corrected from the resonance frequency f1 of the coil to the resonance frequency f2 of the coil to control the susceptor according to the target temperature profile.

<FIG> is a graph illustrating an example in which a frequency of a PWM signal is changed.

As a user input is received for an aerosol generating device, a controller may start operation of the aerosol generating device. For example, the controller may start the operation of the aerosol generating device by receiving the user input through interfacing elements (e.g., a button or a touch screen).

<FIG> illustrates a waveform of a PWM signal of a DC voltage generated by a controller. A frequency of an AC voltage applied to a coil may be determined according to a frequency of the PWM signal. In other words, as the frequency of the PWM signal is changed from f1 through f6, the frequency of the AC voltage applied to the coil is also changed from f1 through f6.

The controller may start an operation for determining a resonance frequency by switching a mode of the aerosol generating device from a sleep mode to a test mode at t1.

At each of frequencies f1, f2, f3, f4, and f5, an input voltage may be the same, and each PWM duty ratio may also be the same. The frequencies f1 and f5 may be the same, and the frequencies f2 and f4 may also be the same. A frequency of a PWM signal generated by the controller may be changed by repeatedly increasing and decreasing within a preset range.

<FIG> illustrates merely one period from t1 to t2, but the controller may generate a PWM signal by repeating a period several times to determine a resonance frequency. In an embodiment of <FIG>, there is only one frequency f2 between the frequency f1 and the frequency f3. However, in another embodiment, the steps of changing a frequency may be further divided. The method of changing a frequency is not limited to the example described above.

In an embodiment, when an output current of a coil measured by the controller appears maximum at the frequencies f2 and f4, the controller may determine, as a resonance frequency, the frequency f6 that is the same as the frequencies f2 and f4. After the resonance frequency is determined, the controller may switch the mode of the aerosol generating device from the test mode to a heating mode at t2. In the heating mode, the controller may generate a PWM signal having the frequency f6 and apply, to the coil, an AC voltage having the resonance frequency f6.

<FIG> illustrates an example in which, in the test mode, a frequency increases and then decreases within a preset range. However, the method of changing the frequency is not limited to the example described above, and may include a method of increasing or decreasing a frequency in one direction as well as a method of decreasing first and then increasing a frequency within a preset range.

The time period from t1 to t2 for the test mode may be a short time, which may not be recognized by a user. For example, the time period from t1 to t2 may be about <NUM> seconds to about <NUM> seconds. Alternatively, the time period may be <NUM> second.

In another embodiment, a frequency of a PWM signal generated by the controller may be fixed, and a duty ratio of the PWM signal may be generated by being changed within a preset range. That is, duty ratios at the frequencies f1, f2, f3, f4, and f5 may not be constant. For example, the duty ratios at the frequencies f1 and f5 may be the same, and the duty ratios at the frequencies f2 and f4 may also be the same. The duty ratio of the PWM signal generated by the controller may be changed by repeatedly increasing and decreasing within a preset range. As the duty ratio is changed, an amount of power supplied to the coil may be changed. As the duty ratio of the PWM signal increases, the amount of the power supplied to the coil may increase, and heating of a susceptor may be accelerated.

However, the method of changing the duty ratio is not limited to the examples described above, and may include a method of increasing or decreasing the duty ratio in one direction as well as a case of decreasing first and then increasing the duty ratio within a preset range.

<FIG> is a flowchart illustrating a method of controlling an aerosol generating device, according to one embodiment.

Referring to <FIG>, in operation <NUM>, an aerosol generating device may apply a test voltage to a coil in response to a user input.

In the aerosol generating device, a resonance frequency corresponding to a design standard of the coil is stored in a memory. However, even when the coil is made of the same standard and material, resistance deviation may occur in a production and assembly process, and thus, the resonance frequency may vary. The aerosol generating device may apply the test voltage to the coil in response to the user input to determine the resonance frequency, which might have been affected by such deviation, before a susceptor is heated.

In operation <NUM>, the aerosol generating device may measure an output current of the coil, which varies as a frequency of the test voltage is changed.

In operation <NUM>, the aerosol generating device may determine a frequency at which the output current becomes maximum.

The frequency at which the output current becomes maximum may be a resonance frequency of the coil. The aerosol generating device may measure the output current of the coil and thereby determine, as a resonance frequency, a frequency corresponding to a maximum output current. As such, the resonance frequency which is affected by resistance deviation may be corrected.

In operation <NUM>, the aerosol generating device may apply an operating voltage having the determined frequency to the coil.

The aerosol generating device may flow the maximum output current through the coil by applying the operating voltage having the determined frequency to the coil. Compared to when an AC voltage having a non-resonance frequency is applied to the coil, a larger output current may flow through the coil due to resonance when the aerosol generating device applies the operating voltage having the resonance frequency to the coil, even if the same power is supplied to the coil. Therefore, the strength of a magnetic field generated by the coil may increase, and thus, the susceptor may be heated according to a target temperature profile.

<FIG> is a flowchart illustrating in more detail the method of <FIG> of controlling an aerosol generating device, according to one embodiment.

Referring to <FIG>, in operation <NUM>, an aerosol generating device may apply a test voltage to a coil by using a PWM signal.

In detail, the aerosol generating device may be supplied with a DC voltage from a battery and thus generate a PWM signal of a DC voltage. The aerosol generating device may convert the PWM signal into an AC voltage and apply the AC voltage to the coil.

In operation <NUM>, the aerosol generating device may change, within a preset range, a frequency of the test voltage applied to the coil.

The PWM signal generated by the aerosol generating device may be a fixed voltage and a frequency of the PWM signal may vary over time. A preset range in which a controller changes a frequency may differ according to a design standard of the coil. For example, when a resonance frequency according to the design standard of the coil is <NUM>, the preset range in which the controller changes the frequency may be about <NUM> to about <NUM>. However, this is merely one embodiment, and the preset range in which the controller changes the frequency is not limited thereto.

In operation <NUM>, the aerosol generating device may measure an output current of the coil.

As a frequency of the AC voltage applied to the coil is changed, the output current flowing through the coil varies. The aerosol generating device may use a feedback circuit to transmit, to the controller, the output current of the coil, which continuously varies as a frequency of the AC voltage applied to the coil is changed.

In operation <NUM>, the aerosol generating device may determine whether or not a maximum value of the measured output current is greater than or equal to a reference value of a preset output current. On the basis of a result of operation <NUM>, the aerosol generating device may control power supplied to the coil.

The reference value of the preset output current may be a minimum value of the output current flowing through the coil which enables the aerosol generating device to operate normally. The reference value of the preset output current may be set on the basis of a design standard of the aerosol generating device. When the aerosol generating device determines that the maximum value of the measured output current is less than the reference value of the preset output current, the aerosol generating device may not enter the heating mode and may stop supplying power to the coil. Also, the aerosol generating device may output a notification that the aerosol generating device may not operate. The aerosol generating device may induce replacement of the aerosol generating device by notifying a user that the aerosol generating device may not operate due to the invalidity of the coil.

When the aerosol generating device determines that the maximum value of the measured output current is greater than or equal to the reference value of the preset output current, the method may proceed to operation <NUM>. In operation <NUM>, the aerosol generating device may determine a frequency at which the output current becomes maximum. The determine frequency may be a resonance frequency of the coil.

In operation <NUM>, the aerosol generating device may apply an operating voltage having the determined frequency to the coil. The aerosol generating device may start heating of a susceptor by switching the test mode to a heating mode.

At least one of the components, elements, modules or units (collectively "components" in this paragraph) represented by a block in the drawings, such as the controller <NUM>, the vaporizer <NUM>, or the MCU <NUM> may be embodied as various numbers of hardware, software and/or firmware structures that execute respective functions described above, according to an exemplary embodiment. For example, at least one of these components may use a direct circuit structure, such as a memory, a processor, a logic circuit, a look-up table, etc. that may execute the respective functions through controls of one or more microprocessors or other control apparatuses. Also, at least one of these components may be specifically embodied by a module, a program, or a part of code, which contains one or more executable instructions for performing specified logic functions, and executed by one or more microprocessors or other control apparatuses. Further, at least one of these components may include or may be implemented by a processor such as a central processing unit (CPU) that performs the respective functions, a microprocessor, or the like. Two or more of these components may be combined into one single component which performs all operations or functions of the combined two or more components. Also, at least part of functions of at least one of these components may be performed by another of these components. Further, although a bus is not illustrated in the above block diagrams, communication between the components may be performed through the bus. Functional aspects of the above exemplary embodiments may be implemented in algorithms that execute on one or more processors. Furthermore, the components represented by a block or processing steps may employ any number of related art techniques for electronics configuration, signal processing and/or control, data processing and the like.

Claim 1:
An aerosol generating device (<NUM>) comprising:
a susceptor (<NUM>) configured to heat an aerosol generating article;
a coil (<NUM>) surrounding the susceptor (<NUM>) and configured to heat the susceptor (<NUM>) by generating a magnetic field when an alternating current voltage is applied; and
a controller (<NUM>) electrically connected to the coil (<NUM>) and configured to:
apply a test voltage to the coil (<NUM>) in response to a user input,
measure an output current of the coil (<NUM>) while changing a frequency of the test voltage,
determine a frequency at which the output current becomes maximum, and
apply an operating voltage having the determined frequency to the coil (<NUM>),
wherein the controller (<NUM>) is configured to determine the frequency at which the output current becomes maximum within a preset range by changing the frequency of the test voltage within the preset range, and
characterised in that
the controller (<NUM>), based on a maximum value of the output current measured within the preset range being less than a preset reference value, is configured to determine that the coil (<NUM>) is abnormal, and is configured not to supply power to the coil (<NUM>).