Patent Publication Number: US-2023137819-A1

Title: Heater assembly and method of manufacturing the same

Description:
TECHNICAL FIELD 
     The present disclosure relates to a heater assembly of an aerosol generating device and a method of manufacturing the heater assembly. 
     BACKGROUND ART 
     Recently, the demand for alternative methods to overcome the shortcomings of general cigarettes has increased. For example, there is growing demand for a method of generating an aerosol by heating an aerosol generating material in cigarettes at a relatively low temperature, rather than by combusting cigarettes. 
     In addition, a research into a heater assembly of a heating-type aerosol generating device is being actively conducted. Examples of a heater assembly for heating an aerosol generating material include a resistance heating-type heater assembly and an induction heating-type heater assembly. Recently, the demand for the induction heating-type heater assembly which is capable of performing heating at a relatively low temperature is increasing. 
     DISCLOSURE OF INVENTION 
     Technical Problem 
     There is need for a heater assembly which is excellent in electrical efficiency, manufacturability, and/or productivity. 
     The problems to be solved by embodiments are not limited to the above-described problems, and undescribed problems may be clearly understood by those skilled in the art related to the present disclosure from the present specification and the accompanying drawings. 
     Solution to Problem 
     According to a first aspect of the present disclosure, a heater assembly for heating an aerosol generating material may include an accommodation portion configured to accommodate the aerosol generating material; an induction coil coupled to an outer surface of the accommodation portion; a susceptor located in the accommodation portion and configured to generate heat by an alternating magnetic field generated by a current flowing through the induction coil; and a support element coupled to the susceptor such that the suspector is spaced apart from an inner surface of the accommodation portion by the support element, wherein the induction coil includes a wire including a conductor, an insulator surrounding the conductor, and a bonding member surrounding the insulator. 
     According to a second aspect of the present disclosure, a heater assembly for heating an aerosol generating material may include an accommodation portion configured to accommodate the aerosol generating material; an induction coil coupled to an outer surface of the accommodation portion; a susceptor located in the accommodation portion and configured to generate heat by an alternating magnetic field generated by a current flowing through the induction coil; and a support element arranged between the susceptor and the accommodation portion such that the suspector is separated from an inner surface of the accommodation portion by a predetermined distance, wherein the induction coil includes a wire including a conductor and an insulator surrounding the conductor, and the induction coil is wrapped by a bonding element. 
     According to a third aspect of the present disclosure, a method of manufacturing a heater assembly for heating an aerosol generating material may include forming a susceptor assembly by coupling a susceptor to a support element; locating the susceptor assembly in the accommodation portion for accommodating the aerosol generating material such that the susceptor is spaced apart by a predetermined distance from an inner surface of the accommodation portion by the support element; forming an induction coil in a shape corresponding to an outer surface of the accommodation portion by winding a wire including a conductor, an insulator, and a bonding member; heating the induction coil to a predetermined temperature such that the bonding member melts; cooling the induction coil such that the molten bonding member solidifies and the shape of the induction coil is fixed by the solidified bonding member; and fitting the induction coil around the outer surface of the accommodation portion. 
     According to a fourth aspect of the present disclosure, a method of manufacturing a heater assembly for heating an aerosol generating material may include forming a susceptor assembly by coupling a susceptor to a support element; locating the susceptor assembly in the accommodation portion for accommodating the aerosol generating material such that the susceptor is spaced apart from an inner surface of the accommodation portion by the support element; forming an induction coil in a shape corresponding to an outer surface of the accommodation portion by winding a wire including a conductor and an insulator; wrapping the induction coil with a bonding element such that a shape of the induction coil is fixed by the bonding element; and fitting the induction coil around the outer surface of the accommodation portion. 
     Advantageous Effects of Invention 
     According to the present disclosure, electrical efficiency of a heater assembly may be improved by increasing inductance of an induction coil. In addition, it is possible to improve assembly properties and productivity and to reduce manufacturing cost by simplifying a configuration of a heater assembly. 
     Effects of the embodiments are not limited to the above-described effects, and undescribed effects will be clearly understood by those skilled in the art related to the present disclosure from the present specification and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a view showing an example in which a cigarette is inserted into an aerosol generating device; 
         FIG.  2    shows a view showing an example of a cigarette; 
         FIG.  3 A  is a cross-sectional view of a heater assembly according to an embodiment; 
         FIG.  3 B  is a cross-sectional view of a heater assembly according to another embodiment; 
         FIG.  4 A  is an exploded view of a susceptor assembly according to an embodiment; 
         FIG.  4 B  is an exploded view of a susceptor assembly according to another embodiment; 
         FIG.  5    shows cross-sectional views of induction coils including bonding members according to various embodiments; 
         FIG.  6    shows a cross-sectional view of an induction coil wrapped by a bonding element according to an embodiment; 
         FIG.  7    is a flowchart of a method of manufacturing a heater assembly, according to an embodiment; 
         FIG.  8    is a flowchart of a method of manufacturing a heater assembly according to another embodiment; and 
         FIG.  9    is a block diagram showing a hardware configuration of an aerosol generating device according to an embodiment. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     According to the present disclosure, a heater assembly for heating an aerosol generating material may include an accommodation portion configured to accommodate the aerosol generating material; an induction coil coupled to an outer surface of the accommodation portion; a susceptor located in the accommodation portion and configured to generate heat by an alternating magnetic field generated by a current flowing through the induction coil; and a support element coupled to the susceptor such that the suspector is spaced apart from an inner surface of the accommodation portion by the support element, wherein the induction coil includes a wire including a conductor, an insulator surrounding the conductor, and a bonding member surrounding the insulator. 
     The induction coil may have a shape corresponding to the outer surface of the accommodation portion, the induction coil may be fixed in the shape when the bonding member is heated to a predetermined temperature and then cooled, and the predetermined temperature may not exceed heat resistance temperatures of the conductor and the insulator, and may be greater than or equal to a heat resistance temperature of the bonding member. 
     The heater assembly may further include a fixing element arranged in a gap between the support element and the accommodation portion such that the support element is fixed to the accommodation portion. 
     The susceptor may have a hollow tubular shape having a susceptor opening, and the support element may have a cap shape having a support element opening, a diameter of the support element opening may be greater than a diameter of the susceptor opening, and the support element may be coupled to the susceptor so that the center of the support element opening coincides with the center of the susceptor opening. 
     The support element may include a first cap and a second cap, and the first cap may wrap at least part of an upper surface of the susceptor and at least part of an outer surface of the susceptor, and the second cap may wrap at least part of a lower surface of the susceptor and at least part of the outer surface of the susceptor. 
     The bonding member may include at least one of polyamide and polyvinyl butyral. 
     The support element may include a high heat-resisting material and configured to block heat transfer from the susceptor to the accommodation portion. 
     The induction coil may include a litz wire made by splicing wires, each of the wires including the conductor, the insulator surrounding the conductor, and the bonding member surrounding the insulator. 
     According to the present disclosure, a heater assembly for heating an aerosol generating material may include an accommodation portion configured to accommodate the aerosol generating material; an induction coil coupled to an outer surface of the accommodation portion; a susceptor located in the accommodation portion and configured to generate heat by an alternating magnetic field generated by a current flowing through the induction coil; and a support element arranged between the susceptor and the accommodation portion such that the suspector is separated from an inner surface of the accommodation portion by a predetermined distance, wherein the induction coil includes a wire including a conductor and an insulator surrounding the conductor, and the induction coil is wrapped by a bonding element. 
     The induction coil may have a shape corresponding to the outer surface of the accommodation portion, and the induction coil may maintain the shape by the bonding element. 
     The heater assembly may further include a fixing element arranged in a gap between the support element and the accommodation portion such that the support element is fixed to the accommodation portion. 
     The susceptor may have a hollow tubular shape having a susceptor opening, and the support element may have a cap shape having a support element opening, a diameter of the support element opening may be greater than a diameter of the susceptor opening, and the support element may be coupled to the susceptor so that the center of the support element opening coincides with the center of the susceptor opening. 
     The support element may include a first cap and a second cap, and the first cap may wrap at least part of an upper surface of the susceptor and at least part of an outer surface of the susceptor, and the second cap may wrap at least part of a lower surface of the susceptor and at least part of the outer surface of the susceptor. 
     A material of the bonding element may be polyimide. 
     The support element may be formed of a high heat-resisting material for blocking heat transfer from the susceptor to the accommodation portion. 
     The induction coil may include a litz wire made by twisting wires. 
     According to the present disclosure, a method of manufacturing a heater assembly for heating an aerosol generating material may include forming a susceptor assembly by coupling a susceptor to a support element for supporting the susceptor; 
     locating the susceptor assembly in the accommodation portion for accommodating the aerosol generating material such that the susceptor is spaced apart by a predetermined distance from an inner surface of the accommodation portion by the support element; forming an induction coil in a shape corresponding to an outer surface of the accommodation portion by winding a wire including a conductor, an insulator, and a bonding member; heating the induction coil to a predetermined temperature such that the bonding member melts; cooling the induction coil such that the molten bonding member solidifies and the shape of the induction coil is fixed by the solidified bonding member; and fitting the induction coil around the outer surface of the accommodation portion. 
     According to the present disclosure, a method of manufacturing a heater assembly for heating an aerosol generating material may include forming a susceptor assembly by coupling a susceptor to a support element; locating the susceptor assembly in the accommodation portion for accommodating the aerosol generating material such that the susceptor is spaced apart from an inner surface of the accommodation portion by the support element; forming an induction coil in a shape corresponding to an outer surface of the accommodation portion by winding a wire including a conductor and an insulator; wrapping the induction coil with a bonding element such that a shape of the induction coil is fixed by the bonding element; and fitting the induction coil around the outer surface of the accommodation portion. 
     MODE FOR THE INVENTION 
     With respect to the terms used to describe the various embodiments, general terms which are currently and widely used are selected in consideration of functions of structural elements in the various embodiments of the present disclosure. However, meanings of the terms can be changed according to intention, a judicial precedence, the appearance of new technology, and the like. In addition, in certain cases, a term which is not commonly used can be selected. In such a case, the meaning of the term will be described in detail at the corresponding portion in the description of the present disclosure. Therefore, the terms used in the various embodiments of the present disclosure should be defined based on the meanings of the terms and the descriptions provided herein. 
     In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. In addition, the terms “-er”, “-or”, and “module” described in the specification mean units for processing at least one function and/or operation and can be implemented by hardware components or software components and combinations thereof. 
     As used herein, expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. For example, the expression, “at least one of a, b, and c,” should be understood as including only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c. 
     It will be understood that when an element or layer is referred to as being “over,” “above,” “on,” “connected to” or “coupled to” another element or layer, it can be directly over, above, on, connected or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly over,” “directly above,” “directly on,” “directly connected to” or “directly coupled to” another element or layer, there are no intervening elements or layers present. Like numerals refer to like elements throughout. 
     The term “aerosol generating article” may refer to any article that is designed for smoking by a person puffing on the aerosol generating article. The aerosol generating article may include an aerosol generating material that generates aerosols when heated even without combustion. For example, one or more aerosol generating articles may be loaded in an aerosol generating device and generate aerosols when heated by the aerosol generating device. The shape, size, material, and structure of the aerosol generating article may differ according to embodiments. Examples of the aerosol generating article may include, but are not limited to, a cigarette-shaped substrate and a cartridge. Hereinafter, the term “cigarette” (i.e., when used alone without a modifier such as “general,” “traditional,” or “combustive”) may refer to an aerosol generating article which has a shape similar to a traditional combustive cigarette. 
     Hereinafter, the present disclosure will now be described more fully with reference to the accompanying drawings, in which embodiments of the present disclosure are shown such that one of ordinary skill in the art may easily work the present disclosure. The disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. 
     In addition, terms including ordinal numbers such as “first” or “second” used in the present specification may be used to describe various components, but the components should not be limited by terms. Terms are used only to distinguish one component from another. 
     In addition, some of the components of the drawings may be shown to be somewhat exaggerated in size and ratio. In addition, components shown on some drawings may not be shown on other drawings. 
     Hereinafter, the present disclosure will be described in detail with reference to the drawings. 
       FIG.  1    is a view showing example in which a cigarette is inserted into an aerosol generating device. 
     Referring to  FIG.  1   , an aerosol generating device  100  includes a heater assembly  104 , a processor  105 , and a battery  106 . In addition, at least a part of an aerosol generating material or a cigarette  200  may be accommodated in the heater assembly  104  of the aerosol generating device  100 . 
     Only some components of the aerosol generating device  100  related to the present embodiment are shown in  FIG.  1   . Therefore, those skilled in the art related to the present embodiment may understand that other general-purpose components other than the components shown in  FIG.  1    may be further included in the aerosol generating device  100 . 
       FIG.  1    shows that the battery  106 , the processor  105 , and the heater assembly  104  are arranged in a row. However, an internal structure of the aerosol generating device  100  is not limited to the structure shown in  FIG.  1   . In other words, the arrangement of the battery  106 , the processor  105 , and the heater assembly  104  may be changed according to a design of the aerosol generating device  100 . 
     When the cigarette  200  is inserted into the aerosol generating device  100 , the aerosol generating device  100  operates the heater assembly  104  to generate an aerosol from the cigarette  200 . The aerosol generated by the heater assembly  104  passes through the cigarette  200  to be delivered to a user. 
     If necessary, the aerosol generating device  100  may operate the heater assembly  104  even when the cigarette  200  is not inserted into the aerosol generating device  100 . 
     The battery  106  supplies power used to operate the aerosol generating device  100 . For example, the battery  106  may supply power to allow the heater assembly  104  to operate, and specifically, the battery  106  may supply power to allow the induction coil  103  to generate an alternating magnetic field. 
     In addition, the battery  106  may supply power required for the processor  105  to operate. In addition, the battery  106  may supply power required to operate a display, a sensor, a motor, and so on installed in the aerosol generating device  100 . 
     The processor  105  controls an overall operation of the aerosol generating device  100 . Specifically, the processor  105  controls not only operations of the battery  106  and the induction coil  103  but also operations of other components included in the aerosol generating device  100 . In addition, the processor  105  may also determine whether or not the aerosol generating device  100  is in an operable state by checking a state of each component of the aerosol generating device  100 . 
     The processor  105  may be two or more processors. The processor may also consist of an array of a plurality of logic gates or may also consist of a combination of a general-purpose microprocessor and a memory in which a program executable in the microprocessor is stored. In addition, those skilled in the art related to the present embodiment may understand that the processor may consist of another type of hardware. 
     The heater assembly  104  may be operated by power supplied from the battery  106 . For example, when a cigarette is inserted into the aerosol generating device  100 , the cigarette may be accommodated in an accommodation portion  101  of the heater assembly  104 . Therefore, a heating element of the heater assembly  104  may raise a temperature of an aerosol generating material in the cigarette. 
     The heating element of the heater assembly  104  may be an induction heating type heater. Specifically, the heater assembly  104  may include an electrically conductive induction coil  103  for heating a susceptor  102  by an induction heating method. The susceptor  102  may be arranged in the aerosol generating device  100  or may be included in the cigarette  200 . 
     However, the heating element is not limited to the above-described example and may be applicable without limitation as long as the heating element may perform heating to a desirable temperature. Here, the desirable temperature may be preset in the aerosol generating device  100  or may be set by a user. 
     For example, the heater assembly  104  may include a tube-shaped heating element, a plate-shaped heating element, a needle-shaped heating element, or a rod-shaped heating element, and may heat the inside or the outside of the cigarette  200  depending on the shape of the heating element. 
     In addition, a plurality of heating elements may also be arranged in the aerosol generating device  100 . In this case, the heating elements may be arranged to be inserted into the cigarette  200  or may be arranged outside the cigarette  200 . According to an embodiment, some of the heating elements included in the plurality of heater assemblies  104  may be arranged to be inserted into the cigarette  200 , and the rest may be arranged outside the cigarette  200 . In addition, the shape of the heater assembly  104  is not limited to the shape shown in  FIG.  1    and may be variously formed. 
     In addition, the induction coil  103  may be located around the accommodation portion  101 .  FIG.  1    shows that the induction coil  103  is arranged to surround the accommodation portion  101 , but it is not limited thereto. 
     When the cigarette  200  is accommodated in the accommodation portion  101  of the aerosol generating device  100 , the aerosol generating device  100  may supply power to the induction coil  103  such that the induction coil  103  generates an alternating magnetic field. As the alternating magnetic field generated by the induction coil  103  passes through the susceptor  102 , the susceptor  102  may be heated. As the aerosol generating material in the cigarette  200  is heated by the heated susceptor  102 , an aerosol may be generated. The generated aerosol passes through the cigarette  200  to be delivered to a user. 
     The induction coil  103  may be an electrically conductive coil that generates an alternating magnetic field by using power supplied from the battery  106 . The induction coil  103  may be arranged to surround at least a part of the accommodation portion  101 . The alternating magnetic field generated by the induction coil  103  may be applied to the susceptor  102  arranged at an inner side of the accommodation portion  101 . 
     The susceptor  102  may be heated as the alternating magnetic field generated by the induction coil  103  passes through the susceptor  102  and may include metal or carbon. For example, the susceptor  102  may include at least one of ferrite, a ferromagnetic alloy, stainless steel, and aluminum. 
     In addition, the susceptor  102  may include ceramic (e.g., graphite, molybdenum, silicon carbide, niobium, a nickel alloy, a metal film, or zirconia), a transition metal (e.g., nickel (Ni) or cobalt (Co)), and/or a metalloid (e.g., boron (B) or phosphorus (P)). However, the susceptor  102  is not limited to the above-described example and may be applicable without limitation as long as the susceptor may be heated to a desirable temperature as an alternating magnetic field is applied. Here, the desirable temperature may be preset in the aerosol generating device  100  or may be set by a user. 
     When the cigarette  200  is accommodated in the accommodation portion  101  of the aerosol generating device  100 , the susceptor  102  may be located outside the cigarette  200 . Therefore, the heated susceptor  102  may increase a temperature of the aerosol generating material in the cigarette  200 . 
       FIG.  1    shows that the susceptor  102  is arranged to surround and heat the outside of the cigarette  200 , but it is not limited thereto. For example, the susceptor  102  may have a tubular shape, a plate shape, a needle shape or a rod shape, and may be arranged to heat the inside or the outside of the cigarette  200  depending on the shape of the susceptor  102 . 
     In addition, a plurality of susceptors  102  may also be arranged in the aerosol generating device  100 . In this case, the plurality of susceptors  102  may be arranged to be inserted into the cigarette  200  or may be arranged outside the cigarette  200 . According to an embodiment, some of the plurality of susceptors  102  may be arranged to be inserted into the cigarette  200 , and the rest may be arranged outside the cigarette  200 . In addition, the shape of the susceptor  102  is not limited to the shape shown in  FIG.  1    and may be variously formed. 
     In addition, the aerosol generating device  100  may include other general-purpose components in addition to the heater assembly  104 , the processor  105 , and the battery  106 . For example, the aerosol generating device  100  may include a display capable of outputting visual information and/or a motor for outputting tactile information. In addition, the aerosol generating device  100  may include at least one sensor (e.g., a puff detection sensor, a temperature detection sensor, a cigarette insertion detection sensor, or so on). In addition, the aerosol generating device  100  may have a structure in which external air may flow in or internal gas may flow out even while the cigarette  200  is inserted in the aerosol generating device  100 . 
     Although not shown in  FIG.  1   , the aerosol generating device  100  may also constitute a system together with a separate cradle. For example, the cradle may be used to charge the battery  106  of the aerosol generating device  100 . The heater assembly  104  may also be heated while the cradle and the aerosol generating device  100  are coupled to each other. 
     The cigarette  200  may be similar to a general combustion type cigarette in shape and structure. For example, the cigarette  200  may be divided into a first portion including an aerosol generating material and a second portion including a filter. According to an embodiment, an aerosol generating material may also be included in the second portion of the cigarette  200 . For example, an aerosol generating material made in the form of granules or capsules may also be inserted into the second portion. 
     When the cigarette is loaded in the aerosol generating device  100 , the entire first portion may be inserted into the aerosol generating device  100  and the second portion may be exposed to the outside. According to an embodiment, only part of the first portion may be inserted into the aerosol generating device  100 . According to an embodiment, the entire first portion and art of the second part may also be inserted into the aerosol generating device  100 . A user may puff an aerosol while holding the second portion by the mouth of the user. In this case, the aerosol is generated as external air passes through the first portion, and the generated aerosol is delivered to the mouth of the user through the second portion. 
     As an example, external air may flow in through at least one air passage formed in the aerosol generating device  100 . For example, opening and closing of the air passage formed in the aerosol generating device  100  and/or a size of the air passage may be adjusted by a user. Accordingly, the amount of smoke (i.e., aerosol) and a smoking feeling may be adjusted by the user. As another example, external air may also flow into the cigarette  200  through at least one hole formed in a surface of the cigarette  200 . 
     Hereinafter, an example of the cigarette  200  will be described with reference to  FIG.  2   . 
       FIG.  2    shows a view showing an example of a cigarette. 
     Referring to  FIG.  2   , the cigarette  200  includes a tobacco rod  210  and a filter rod  220 . The first portion described above with reference to  FIG.  1    may include the tobacco rod  210 , and the second portion may include the filter rod  220 . 
       FIG.  2    illustrates that the filter rod  220  includes a single segment, but is limited thereto. In other words, the filter rod  220  may include a plurality of segments. For example, the filter rod  220  may include a first segment configured to cool an aerosol and a second segment configured to filter a certain component included in the aerosol. Also, as necessary, the filter rod  220  may further include at least one segment configured to perform other functions. 
     The cigarette  200  may be packaged by at least one wrapper  240 . The wrapper  240  may have at least one hole through which external air may be introduced or internal air may be discharged. For example, the cigarette  200  may be packaged by one wrapper  240 . As another example, the cigarette  200  may be doubly packaged by two or more wrappers  240 . For example, the tobacco rod  210  may be packaged by a first wrapper, and the filter rod  220  may be packaged by a second wrapper. Also, the tobacco rod  210  and the filter rod  220 , which are respectively packaged by separate wrappers, may be coupled to each other, and the entire cigarette  200  may be packaged by a third wrapper. When each of the tobacco rod  210  or the filter rod  220  is composed of a plurality of segments, each segment may be packaged by separate wrappers. Also, the entire cigarette  200  including the plurality of segments, which are respectively packaged by the separate wrappers and which are coupled to each other, may be repackaged by another wrapper. 
     The tobacco rod  210  may include an aerosol generating material. For example, the aerosol generating material may include at least one of glycerin, propylene glycol, ethylene glycol, dipropylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, and oleyl alcohol, but it is not limited thereto. Also, the tobacco rod  210  may include other additives, such as flavors, a wetting agent, and/or organic acid. Also, the tobacco rod  210  may include a flavored liquid, such as menthol or a moisturizer, which is injected to the tobacco rod  210 . 
     The tobacco rod  210  may be manufactured in various forms. For example, the tobacco rod  210  may be formed as a sheet or a strand. Also, the tobacco rod  210  may be formed as a pipe tobacco, which is formed of tiny bits cut from a tobacco sheet. Also, the tobacco rod  210  may be surrounded by a heat conductive material. 
     For example, the heat-conducting material may be, but is not limited to, a metal foil such as aluminum foil. For example, the heat conductive material surrounding the tobacco rod  210  may uniformly distribute heat transmitted to the tobacco rod  210 , and thus, the heat conductivity applied to the tobacco rod may be increased and taste of the tobacco may be improved. Also, the heat conductive material surrounding the tobacco rod  210  may function as a susceptor heated by the induction heater. Here, although not illustrated in the drawings, the tobacco rod  210  may further include an additional susceptor, in addition to the heat conductive material surrounding the tobacco rod  210 . 
     The filter rod  220  may include a cellulose acetate filter. Shapes of the filter rod  220  are not limited. For example, the filter rod  220  may include a cylinder-type rod or a tube-type rod having a hollow inside. Also, the filter rod  220  may include a recess-type rod. When the filter rod  220  includes a plurality of segments, at least one of the plurality of segments may have a different shape. 
     The filter rod  220  may be formed to generate flavors. For example, a flavoring liquid may be injected onto the filter rod  220 , or an additional fiber coated with a flavoring liquid may be inserted into the filter rod  220 . Also, the filter rod  220  may include at least one capsule  230 . Here, the capsule  230  may perform a function of generating a flavor or an aerosol. For example, the capsule  230  may have a configuration in which a liquid containing a flavoring material is wrapped with a film. For example, the capsule  230  may have a spherical or cylindrical shape, but is not limited thereto. 
     When the filter rod  220  includes a segment configured to cool the aerosol, the cooling segment may include a polymer material or a biodegradable polymer material. For example, the cooling segment may include pure polylactic acid alone, but the material for forming the cooling segment is not limited thereto. In some embodiments, the cooling segment may include a cellulose acetate filter having a plurality of holes. However, the cooling segment is not limited to the above-described example and is not limited as long as the cooling segment cools the aerosol. 
     Meanwhile, although not illustrated in  FIG.  2   , the cigarette  200  according to an embodiment may further include a front-end filter. The front-end filter may be located on one side of the tobacco rod  210  which is opposite to the filter rod  220 . The front-end filter may prevent the tobacco rod  210  from being detached outwards and prevent the liquefied aerosol from flowing from the tobacco rod  210  into the aerosol generating device ( 100  of  FIG.  1   ), during smoking. 
     Hereinafter, a heater assembly will be described with reference to  FIGS.  3 A and  3 B . 
       FIG.  3 A  is a cross-sectional view of a heater assembly according to an embodiment. 
       FIG.  3 A  shows components of a heater assembly  300  for heating an aerosol generating material. The heater assembly  300  may include an accommodation portion  310  that accommodates an aerosol generating material, an induction coil  340  wound around an outer surface of the accommodation portion  310 , and a susceptor  320  that is located in the accommodation portion  310 . The susceptor  320  may be heated by an alternating magnetic field, which is induced by a current flowing through the induction coil  340 . 
     In addition, the heater assembly  300  may include a support element that fixes a position of the susceptor  320  and separates the susceptor  320  by a predetermined distance from an inner surface of the accommodation portion  310 , and a fixing element  350  that fixes the support element  330  to the accommodation portion  310  by being fitted into a gap between the support element and the accommodation portion  310 . 
     However, it is obvious to those skilled in the art that some of the components of the heater assembly  300  shown in  FIG.  3 A  may be omitted or other general-purpose components may be further included therein. 
     The accommodation portion  310  according to an embodiment may have a cylindrical shape. Specifically, the accommodation portion  310  may have an opening on one side and a cavity. 
     Components such as a susceptor  320 , a support element  330 , and a fixing element  350  may be located in the cavity of the accommodation portion  310 , and an induction coil  340  may be wound around the outside of the accommodation portion  310 . In addition, an aerosol generating material or a cigarette may be loaded in the cavity of the accommodation portion  310 . 
     The accommodation portion  310  is not limited to a particular shape. For example, the accommodation portion  310  may have a square pillar shape or a triangular pillar shape. The shape of the induction coil  340  formed by a wire wound around an outer surface of the accommodation portion  310  may correspond to the shape of the accommodation portion  310 . For example, the induction coil  340  may have a square pillar shape or a triangular pillar shape. 
     The susceptor  320  may be located in the accommodation portion  310 . A horizontal cross section of the susceptor  320  taken perpendicular to a longitudinal direction of the accommodation portion  310  may be circular. A space between the susceptor  320  and the accommodation portion  310  may be changed according to a cross-sectional shape of the accommodation portion  310 . 
     For example, if the accommodation portion  310  has a square pillar shape, a cross-section thereof may be a square. In this case, when a tubular susceptor  320  is located in the accommodation portion  310 , a space may be formed between the inner surface of the accommodation portion  310  and the susceptor  320 . Accordingly, heat generated by the susceptor  320  may be better dissipated to the outside of the heater assembly  300 . 
     In addition, the accommodation portion  310  may be formed of a plastic polyetherether ketone (PEEK) material which has excellent molding processability, such that the accommodation portion  310  may be easily manufactured in a desirable shape. In addition, the PEEK has high heat resistance, excellent abrasion resistance, impact resistance, and hydrolysis resistance, thus durability of the heater assembly  300  may be improved. 
     The susceptor  320  may be located in the accommodation portion  310  and may have various shapes to heat an aerosol generating material or a cigarette. 
       FIG.  3 A  shows the heater assembly  300  according to an embodiment. The susceptor according to an embodiment may have a tube shape (hereinafter, referred to as a “hollow tubular susceptor  320 ”). 
     An inner diameter of the hollow tubular susceptor  320  may be designed such that an aerosol generating material or an outer surface of a cigarette accommodated in the accommodation portion  310  comes into contact with or is close enough to receive heat from an inner surface  322  of the hollow tubular susceptor  320 . 
     In addition, a length (i.e., a height) of the hollow tubular susceptor  320  may be designed to heat a portion that needs to be heated in a cigarette, for example, a portion including an aerosol generating material in the cigarette. As the hollow tubular susceptor  320  is designed to have dimensions suitable for heating an aerosol generating material or a cigarette, the aerosol generating device including the heater assembly  300  may efficiently generate an aerosol. 
     In addition, the hollow tubular susceptor  320  may be spaced apart from an inner surface of the accommodation portion  310  by the support element  330 . In addition, the hollow tubular susceptor  320  may be coupled to the support element  330  to form a susceptor assembly and may be fixed to the accommodation portion  310 . Details will be described below together with the support element. 
     In addition, the hollow tubular susceptor  320  may be arranged so that the accommodation portion  310  and the hollow tubular susceptor  320  have a common central vertical axis. As such, an aerosol generating material or a cigarette may be easily inserted into the hollow tubular susceptor  320 . 
     In addition, the susceptor  320  may be heated by an induction current or a counter electromotive force generated due to a change in an alternating magnetic field generated by an alternating current flowing through the induction coil  340 . Specifically, the susceptor  320  may be heated by an eddy current loss or a hysteresis loss due to a current induced in the susceptor  320  according to electromagnetic properties of a material forming the susceptor. 
     The support element  330  may have a configuration that fixes a position of the susceptor and separate the susceptor  320  from the inner surface of the accommodation portion  310  by a predetermined distance to prevent heat generated by the susceptor from being directly conducted to the accommodation portion  310 . One or more support elements  330  may be included in the heater assembly  300 . 
     The support element  330  according to an embodiment may have a cap shape (hereinafter, referred to as a “cap-shaped support element  330 ”). A horizontal cross-section of the cap-shaped support element  330  may be a ring shape. The cap-shaped support element  330  may have an upper portion  332  and a side portion  333  vertically extending from an outer edge of the upper portion  332 . 
     In addition, a support element opening  331  may be formed in the upper portion  332  of the cap-shaped support element  330 . A diameter of the support element opening  331  may be greater than a diameter of a susceptor opening  321 . An aerosol generating material or a cigarette may be inserted in the hollow tubular susceptor  320  through the susceptor opening  321 . 
     Accordingly, the cap-shaped support element  330  may be coupled to the hollow tubular susceptor  320  so that the center of the support element opening  331  coincides with the center of the susceptor opening  321 , thereby forming a susceptor assembly. 
     Because the diameter of the support element opening  331  is greater than the diameter of the susceptor opening  321 , the cap-shaped support element  330  may not cover the susceptor opening  321  of the hollow tubular susceptor  320  in a state in which the hollow tubular susceptor  320  and the cap-shaped support element  330  are coupled to each other. Accordingly, a cigarette may be inserted into the hollow tubular susceptor  320  without being disturbed by the cap-shaped support element  330 . 
     In addition, the cap-shaped support element  330  may include a first cap and a second cap. The first cap may cover at least a part of an upper surface and an outer surface of the hollow tubular susceptor  320 , and the second cap may cover at least a part of a lower surface and the outer surface of the hollow tubular susceptor  320 . Accordingly, the hollow tubular susceptor  320  may not be in direct contact with the accommodation portion  310 . 
     The cap-shaped support element  330  has the side portion  333  extending vertically from an outer edge of the upper portion  332 , thereby covering a part of an outer surface  323  of the hollow tubular susceptor  320 . Accordingly, the upper surface, the lower surface, and the outer surface of the hollow tubular susceptor  320  may be in contact with the cap-shaped support element  330 , and thereby, the hollow tubular susceptor  320  and the cap-shaped support element  330  may be more firmly coupled to each other. 
       FIG.  3 B  is a cross-sectional view of a heater assembly according to another embodiment. 
       FIG.  3 B  shows a heater assembly  300  according to another embodiment. The heater assembly according to the present embodiment may include a susceptor  360  (hereinafter, referred to as a “needle-type susceptor”) including a support portion  361  provided at a lower portion and a protrusion  362  protruding from the center of the support portion  361 . The protrusion  362  may be formed in a needle shape having a sharp end. However, the present disclosure is not limited thereto, and the protrusion may be implemented in various manners. For example, the protrusion may have a tubular shape or may be implemented by a plurality of needle shape protrusions. 
     According to an embodiment, the needle-type susceptor  360  may have a roundish end, instead of the pointy end as shown in  FIG.  3 B . That is, the needle-type susceptor  360  may be employed without limitation in shape as long as the susceptor may perform a function of heating an aerosol generating material or a cigarette. 
     The protrusion  362  of a needle shape may be designed to be in thermal contact with the aerosol generating material or the inside of a cigarette accommodated in the accommodation portion  310 . In addition, a length of the needle-type susceptor  360  may be designed to reach a portion that needs to be heated in an aerosol generating material or a cigarette. 
     The support element  370  according to an embodiment (hereinafter, referred to as a “pedestal-type support element”) may be arranged to support a lower end of the support portion  361  of the needle-type susceptor  360 . That is, the protrusion  362  may be formed on one side (e.g., top surface) of the support portion  361 , and the needle-type susceptor  360  support the opposite side (e.g., bottom surface). 
     Specifically, a pedestal-type support element  370  may be coupled to a lower end of the support portion  361  of the needle-type susceptor  360  to form a susceptor assembly. Specifically, the pedestal-type support element  370  may support the needle-type susceptor  360  by covering a lower surface and an outer portion of the support portion. 
     The heater assembly  300  to which the needle-type susceptor  360  is applied may directly heat an aerosol generating material or the inside of a cigarette, and thus, heating efficiency of an aerosol generating device may be increased. 
     The susceptor assembly including the susceptor and the support element may be inserted into the accommodation portion  310  by an interference fit method to be fixed inside the accommodation portion  310 . In addition, the susceptor and the accommodation portion  310  are physically separated by a support element so that there is no mutual contact surface, and thus, heat generated by the susceptor may be prevented from being directly transferred to the accommodation portion  310 . 
     The induction coil  340  may be a wire wound around an outer surface of the accommodation portion  310 . The shape of the induction coil  340  may correspond to the shape of the accommodation portion  310 . 
     For example, when the accommodation portion  310  has a cylindrical shape, the induction coil  340  may be wound in a cylindrical shape. In addition, the wire may be wound so that a length of the induction coil  340  is the same as the length of the susceptor. 
     As will be described below in  FIG.  5   , an inductance value of the induction coil  340  is changed according to the length and cross-sectional area of the induction coil  340 , and thus, heating efficiency may be changed according to the shape and dimensions of the induction coil  340 . 
     In addition, a bobbin may be used as a frame for forming the induction coil  340  having a shape of a wire wound around an outer surface of the accommodation portion. As will be described below in  FIG.  7   , when the shape of the induction coil  340  is determined, a suitable bobbin is made and a wire is wound around the bobbin to make the induction coil  340 , and the induction coil  340  having a desirable shape may be mass-produced by separating the bobbin and the induction coil  340 . 
     According to an embodiment, the fixing element  350  may be further included in the heater assembly  300 . Even though the heater assembly  300  has the support element  330 , the susceptor assembly may not be firmly fixed inside the accommodation portion  310  due to a tolerance of each component. 
     The fixing element  350  may be inserted into a gap between the support element  330  and the accommodation portion  310  to fix the support element  330  to the accommodation portion  310 . As such, the entire susceptor assembly may be firmly fixed inside the accommodation portion  310 . 
     Specifically, a protrusion  351  may be formed at one end of the fixing element  350 , and a groove capable of being coupled to the protrusion  351  may be formed in an inner surface of the accommodation portion  310 . As the protrusion  351  is coupled to the groove of the accommodation portion  310 , the susceptor assembly may be more firmly fixed inside the accommodation portion  310 . 
       FIG.  4 A  is an exploded view of a susceptor assembly according to an embodiment. 
       FIG.  4 A  shows a hollow tubular susceptor  410  and two cap-shaped support elements  420  and  430 . The left cap-shaped support element of the hollow tubular susceptor  410  will be referred to as a first cap  420 , the right cap-shaped support element will be referred to as a second cap  430 . 
     The hollow tubular susceptor  410  may be coupled to the first cap  420  at one end (hereinafter referred to as “first end”), and may be coupled to the second cap  430  at the other end (hereinafter referred to as “second end”). 
     As shown, the hollow tubular susceptor  410  may have an opening (hereinafter, referred to as a “susceptor opening  411 ”) in the first and second ends. In addition, the support elements  420  and  430  may have an opening (hereinafter, referred to as a “support element opening”). As shown in  FIG.  4 A , the support element opening may be formed in each of the first cap  420  and the second cap  430 . 
     For example, a diameter of a first opening  421  formed in an upper portion  422  of the first cap  420  may be greater than a diameter of the susceptor opening  411 . In addition, a diameter of a second opening  431  formed in an upper portion  432  of the second cap  430  may be greater than the diameter of the susceptor opening  411 . 
     Referring to  FIG.  4 A , the first cap  420  may include a first upper portion  422  and a first side portion  423 . The first upper portion  422  may cover at least a part of an upper surface  412  of the hollow tubular susceptor  410 , and the first side portion  423  may cover at least a part of an outer surface  413  of the hollow tubular susceptor  410 . 
     In addition, the second cap  430  may include a second upper portion  432  and a second side portion  433 . The second upper portion  432  may cover at least a part of a lower surface  414  of the hollow tubular susceptor  410 , and the second side portion  433  may cover at least a part of the outer surface  413  of the hollow tubular susceptor  410 . 
     Accordingly, the first cap  420  and the second cap  430  may be coupled to the hollow tubular susceptor  410  to form a susceptor assembly. 
     In addition, the first cap  420  and the second cap  430  may be designed with an interference fit tolerance so that the inner diameters  424  and  434  of the side portions  423  and  433  of the support elements are smaller than an outer diameter of the hollow tubular susceptor  410 . 
     Accordingly, the first cap  420  and the second cap  430  may be coupled to the hollow tubular susceptor  410  without an additional fastening element or an adhesive material. As a result, a production process may be simplified and a production cost may be reduced. 
       FIG.  4 B  is an exploded view of a susceptor assembly according to another embodiment. 
       FIG.  4 B  shows a needle-type susceptor  440  and a pedestal-type support element  450 . As shown, the needle-type susceptor  440  may include a protrusion  441  and a support portion  442 . The protrusion  441  protrudes on an upper surface of the support portion  442 . In addition, the pedestal-type support element  450  may include a lower portion  452  and a side portion  453 . When the needle-type susceptor  440  and the pedestal-type support element  450  are combined, the lower surface of the needle-type susceptor  440  faces the upper surface of the lower portion  452  of the pedestal-type support element  450 . Although not shown, an opening may be formed in the lower portion  452  of the pedestal-type support element  450 . 
     The lower portion  452  may cover at least a part of a lower surface of the support portion  442 , and the side portion  453  may cover at least a part of an outer surface (i.e., side surface) of the support portion  442 . Accordingly, the needle-type susceptor  440  and the pedestal-type support element  450  may be coupled to each other to form the susceptor assembly. 
     In addition, the pedestal-type support element  450  may be designed with an interference fit tolerance so that an inner diameter  454  of the side portion  453  is smaller than a diameter of the support portion  442  of the needle-type susceptor  440 . Accordingly, the needle-type susceptor  440  and the pedestal-type support element  450  may be coupled to each other without a separate fastening element or an adhesive material. 
     The susceptor may generate heat for heating an aerosol generating material or a cigarette, which may have a temperature of approximately 300° C. or higher. A support element may serve to reduce heat being transferred to an accommodation portion from the susceptor. 
     The support element may be formed of a material with a low thermal conductivity to minimize high-temperature heat being transferred to the accommodation portion from the susceptor. In addition, the support element may be made of a high heat-resisting material so as not to be melted by high-temperature heat. 
     In addition, the support element may be formed of a material with excellent mechanical properties so as not to have a change in shape due to heat. In addition, the support element may be formed of a material with excellent electrical properties to be electrically insulated from the accommodation portion and the induction coil. For example, the support element may be formed of PLAVIS. 
     The PLAVIS is a plastic material and has mechanical characteristics including high heat resistance, high abrasion resistance, and low friction, and it also has electrical characteristics including excellent electrical insulation. Thus, the PLAVIS may be a suitable material for a support element. 
     Specifically, the PLAVIS may be used stably at a high temperature of approximately 300° C., and may have a high PV value over a wide temperature range and a low friction coefficient. Also, it has a high tensile strength against temperature and excellent creep properties at a high temperature. As such, a possibility of deformation due to heat may be reduced. In addition, because the PLAVIS maintains electrical insulation over a wide temperature range, it is possible to reduce a chance of a short-circuit between the induction coil and the susceptor. 
       FIG.  5    shows cross-sectional views of induction coils including bonding members according to various embodiments. 
     According to an embodiment, a wire may have a circular cross-sectional shape (a), a square cross-sectional shape (b), or a triangular cross-sectional shape (c). However, the present disclosure is not limited thereto, and those skilled in the art related to the present embodiment may understand that other shapes other than the above-described cross-sectional shapes may be employed. 
     In addition, a wire may include a conductor  511 , an insulator  512 , and a bonding member  513 . Specifically, the insulator  512  may be formed coaxially with the conductor  511  on the outside of the conductor  511 , and the bonding member  513  may be formed coaxially with the insulator  512  on the outside of the insulator  512 . Although  FIG.  5    shows that the bonding member  513  is included, the bonding member  513  may not be included. 
     The inductance value of an induction coil is proportional to the number of turns of the wire per unit length as shown in following Equation 1. 
         L=μ   o   n   2   lA   Equation 1
 
     where μ o  is permeability in vacuum, n is the number of turns of wire per unit length, 1 is a length of the induction coil, and A is a cross-sectional area of the induction coil. 
     The induction coil to which an AC current is applied may generate a counter electromotive force, which is proportional to an inductance value as shown in following Equation 2. 
     
       
         
           
             
               
                 
                   V 
                   = 
                   
                     
                       - 
                       L 
                     
                     ⁢ 
                     
                       di 
                       dt 
                     
                   
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   2 
                 
               
             
           
         
       
     
     where V is the counter electromotive force, L is inductance of the induction coil, and 
     
       
         
           
             di 
             dt 
           
         
       
     
     is proportional to the larger the number n of turns of wire per unit length, the larger the length I of the induction coil, and the cross-sectional area A (i.e., a horizontal cross-sectional area taken along a length direction of the induction coil as shown in  FIG.  5   ). Thus, electrical efficiency of the induction coil may be improved by controlling these parameters. 
     The number of turns of wire per unit length of the induction coil may change depending on cross-sectional shapes of the wire. For example, referring to  FIG.  5   , a coil formed by a wire having a triangular cross-sectional shape of (c) may have a larger number of turns than a coil formed by a wire having a circular cross-sectional shape of (a) for the same cross sectional area. 
     In this way, the induction coil may be formed of wires having various cross-sectional shapes by considering a production cost and electrical efficiency. In addition, the shape of the induction coil changes depending on the shapes of a bobbin around which the wire is wound, and thus, an inductance value may be adjusted by changing a cross-sectional area of the induction coil. 
     The induction coil according to an embodiment may be formed of a wire  510  having a circular cross-sectional shape. The wire may be wound around a bobbin, such that an induction coil may be coupled to an outer surface of an accommodation portion. 
     In addition, when heat treatment is performed on the bonding member  513  while wires are wound, the wires may be bonded to each other, and thereby, the shape of the induction coil may be fixed. 
     For example, a heat treatment temperature may be less than or equal to heat resistance temperatures of the conductor  511  and the insulator  512 , and may be greater than or equal to a heat resistance temperature of the bonding member  513 . As the bonding member  513  is melted by the heat treatment, a gap between adjacent wires to be narrowed and the number of turns of wire per unit length may be increased. 
     When the bonding member  513  is cooled after the heat treatment, the bonding member  513  may be solidified and the adjacent wires may be bonded to each other. Accordingly, the shape of the induction coil may be fixed. 
     Specifically, the bonding member  513  is melted during the bonding of the wires, a space between the adjacent wires of the induction coil may be minimized Referring to a reference numeral  515 , a space between adjacent wires may be wide before the adjacent wires are bonded to each other. On the other hand, referring to a reference numeral  516 , a space between adjacent wires is reduced and fixed after the adjacent wires are bonded to each other. Thus, the space between the adjacent wires may be minimized. 
     As the number of turns of wire per unit length of the induction coil increases, the inductance value may increase. Accordingly, heating efficiency of a heater assembly may be increased, and power consumption of an aerosol generating device using the heater assembly may be reduced. 
     As shown in  FIG.  5   , bonding of the wires may be made in different shapes depending on cross-sectional shape of the wire. In addition, the wires may be bonded differently depending on a heat treatment method of the bonding member  513 , a heat treatment condition (such as a heat treatment temperature or a heat treatment time), and a method of winding a wire on a bobbin. Accordingly, an induction coil having various inductance values may be manufactured. 
     According to an embodiment, wires of an induction coil may be bonded to each other so that a cross-section of the bonded wires has a roundish shape  514 . According to another embodiment, wires of an induction coil may be bonded to each other so that a cross-section of the bonded wires has a rectangular shape  525 . According to another embodiment, wires of an induction coil may be bonded to each other so that a cross-section of the bonded wires has a trapezoid shape  535 . 
     In addition, an induction coil formed of a wire including the bonding member  513  may be heated after the wire is wound, or may be heated by joule&#39;s heat generated by current flow through the coil, so that the wires can be bonded. Accordingly, a shape of the induction coil may be fixed without additional fixing procedure, and thus, a production process of the induction coil may be simplified. 
     In addition, according to a method of fixing an induction coil by using the bonding member  513 , the wires may be bonded by the melted bonding member  513  even in a gap between the wires, and thus, the shape of the induction coil may be more firmly fixed. Accordingly, manufacturability of the induction coil may be improved and assembly procedures of the induction coil and an accommodation portion may be simplified. As a result, the product quality may be improved and the manufacturing costs may be reduced. 
     The bonding member  513  may include polyamide and/or polyvinyl butyral (PVB). It is known that polyamide has excellent adhesiveness and a high melting point due to hydrogen bonds. Also, since polyvinyl butyral has excellent adhesion and thermosetting properties, the polyvinyl butyral may be a suitable material for fixing a shape of an induction coil by bonding wires. 
     In addition, a wire forming an induction coil may include a litz wire which is made by splicing thin wires, each of which includes the conductor  511 , the insulator  512  surrounding the conductor  511 , and the bonding member  513  surrounding the conductor  511 . 
     Specifically, the litz wire may be made by weaving  10  to  100  thin conductive wires, each having a diameter of approximately 0.1 mm, to increase a surface area from a physical point of view and to provide excellent frequency characteristics from an electrical point of view. Accordingly, a skin effect may be reduced, effective resistance of the wire may be reduced, and heating efficiency of an induction coil according to a high-frequency alternating current may be increased. 
       FIG.  6    is a cross-sectional view of an induction coil wrapped by a bonding element according to an embodiment. 
     According to an embodiment, a wire constituting the induction coil may be formed of a conductor  611  and an insulator  612 . Specifically, the insulator  612  may be formed coaxially with the conductor  611  on the outside of the conductor  611 . The wire including the conductor  611  and the insulator  612  does not include a bonding member, and thus, production cost may be reduced. 
     However, if the wires are not fixed by the bonding element  613 , a shape of an induction coil may be deformed by some wires being out of position due to an external force and so on. To prevent this, the induction coil may be wound in a shape that may be coupled to an outer surface  621  of an accommodation portion, and then the outside of the induction coil may be wrapped with a bonding element  613 . Accordingly, the shape of the induction coil may be fixed. 
     In addition, a material forming the bonding element may be polyimide. The polyimide has excellent heat resistance, thereby preventing the bonding element  613  from melting due to heat generated by a susceptor. In addition, the polyimide may have little change in characteristics over a wide temperature range and may have excellent electrical characteristics. 
     For example, when a current flows through the induction coil wrapped by the bonding element  613 , the bonding element  613  may be heated by Joule&#39;s heat. However, since the polyimide has excellent heat resistance, a risk of the phase change of the bonding element may be reduced. 
     The bonding element may be an adhesive film formed of polyimide. An outer portion, an upper portion, an inner portion, and a lower portion of the induction coil may be wrapped by the film without gaps, such that the shape of the induction coil may be fixed. 
     In addition, the polyimide is known to be odorless when vaporized, and thus, it is possible to improve taste of an aerosol generated by the aerosol generating device to which the induction coil fixed by the bonding element  613  is applied. 
     In addition, a wire constituting the induction coil may include a litz wire made by splicing thin wires including the conductor  611  and the insulator  612  surrounding the conductor  611 . 
       FIG.  7    is a flowchart of a method of manufacturing a heater assembly according to an embodiment. 
       FIG.  7    shows a flowchart of a method of manufacturing a heater assembly for heating an aerosol generating material. 
     Referring to step  701 , a susceptor and a support element may be coupled to each other to form a susceptor assembly. As described above, the susceptor may be a hollow tubular susceptor or a needle-type susceptor. In addition, the support element may be a cap-shaped support element or a pedestal-type support element. 
     For example, the susceptor assembly including the hollow tubular susceptor may be formed by coupling a first cap to one end of the hollow tubular susceptor and by coupling a second cap to the other end of the hollow tubular susceptor. 
     As another example, the susceptor assembly including the needle-type susceptor may be formed by coupling a pedestal-type support element to a support portion of the needle-type susceptor. 
     Referring to step  702 , the susceptor assembly may be located and fixed in the accommodation portion so that the susceptor is spaced apart from an inner surface of the accommodation portion by a predetermined distance. That is, the susceptor may be located in the accommodation portion but may not be in direct contact with an inner side of the accommodation portion due to the support element. 
     As described above with reference to  FIG.  3 A , the center of the susceptor assembly may coincide with the center of the accommodation portion. In addition, a fixing element may be inserted into a gap between the support element of the susceptor assembly and the accommodation portion, and thus, the susceptor assembly and the accommodation portion may be more firmly coupled to each other. 
     Referring to step  703 , an induction coil may be formed in a shape capable of being coupled to an outer surface of the accommodation portion (i.e., shape corresponding to the outer surface of the accommodation portion) by winding a wire including a conductor, an insulator, and a bonding member. 
     As described above, the induction coil may be formed by directly winding the wire to the accommodation portion but may be formed by winding a wire around a bobbin to improve assembly properties and productivity. 
     The bobbin may indicate a column around which a wire is wound to form an induction coil suitable for a predesigned shape and dimensions. After a shape of the induction coil is determined, a bobbin corresponding to the shape may be produced, and the induction coil may be mass-produced by winding the wire around the bobbin and separating the induction coil. 
     The mass-produced induction coils may be inserted into and coupled to the accommodation portion, and thus, assembly properties and productivity of the heater assembly may be improved. 
     In addition, according to a method of making a coil by winding a wire around a bobbin, it is not necessary to directly wind the coil around the accommodation portion including the susceptor assembly. Thus, movement of the susceptor assembly in a production process of the heater assembly may be minimized, and thus, it is possible to reduce a possibility of displacement of each of internal components. 
     That is, according to a method of winding the wire around the bobbin, a possibility of producing a defective heater assembly may be reduced, when compared with a method of directly winding the wire around the accommodation portion. 
     Referring to step  704 , a shape of the induction coil may be fixed by heating the induction coil up to a predetermined temperature and then by cooling the induction coil. The predetermined temperature may be less than or equal to a heat resistance temperature of the conductor and the insulator and may be greater than or equal to a heat resistance temperature of the bonding member. 
     Specifically, by melting only the bonding member without damaging the conductor and the insulator, a gap between adjacent wires constituting the induction coil may be minimized That is, when the molten induction coil is cooled, the bonding member may be bonded between adjacent wires while solidifying, and thus, a shape of the induction coil may be fixed. 
     Referring to step  705 , the induction coil having a fixed shape may be coupled to an outer surface of the accommodation portion. The induction coil is wound in a shape that may be coupled to the accommodation portion (i.e., a shape corresponding to the outer surface of the accommodation portion), and the shape is fixed by step  704  (i.e., by heating and cooling of the induction coil). Thus, the induction coil may be coupled to the accommodation portion by fitting the induction coil around the accommodation portion. Accordingly, the heater assembly according to the embodiment may be manufactured. 
       FIG.  8    is a flowchart of a method of manufacturing a heater assembly according to another embodiment. 
     Step  801  and step  802  may be the same as step  701  and step  702  of the method of manufacturing the heater assembly shown in  FIG.  7   . 
     Referring to step  803 , an induction coil may be formed in a shape that may be coupled to an outer surface of an accommodation portion (i.e., shape corresponding to the outer surface of the accommodation portion) by winding a wire including a conductor and an insulator. According to the present embodiment, when compared with the embodiment of  FIG.  7   , the manufacturing costs may be reduced because the wire does not include the bonding member. 
     Referring to step  804 , a shape of the induction coil may be fixed by wrapping the outside of the induction coil with a bonding element. The bonding element may include an adhesive material, and may be made in the form of an adhesive tape or an adhesive film. By winding a surface of the induction coil with the bonding element, the wire may be fixed such that the wire may not be displaced from the set positions. For example, a material forming the bonding element may be polyimide. 
     Referring to step  805 , the fixed induction coil may be coupled to an outer surface of the accommodation portion. The induction coil in which the wire is fixed may be fitted around the accommodation portion such that the wire surrounds the outer surface of the accommodation portion, and thereby, a heater assembly may be manufactured. 
       FIG.  9    is a block diagram showing a hardware configuration of an aerosol generating device according to an embodiment. 
     Referring to  FIG.  9   , an aerosol generating device  900  may include a processor  910 , a heater assembly  920 , a battery  930 , a memory  940 , a sensor  950 , and an interface  960 . 
     The heater assembly  920  is electrically heated by power supplied from the battery  930  under the control of the processor  910 . The heater assembly  920  may be located in an accommodation space of the aerosol generating device  900  that accommodates a cigarette. 
     After a cigarette is inserted through an insertion hole of the aerosol generating device  900  from the outside, the cigarette is placed in the accommodation space. Thereby, one end of the cigarette may be inserted into the heater assembly  920 . Therefore, the heated heater assembly  920  may increase a temperature of the aerosol generating material in the cigarette. The heater assembly  920  may be applicable without limitation as long as the heater assembly may accommodate a cigarette. 
     For stable use of the aerosol generating device  900 , power according to regulation of 3.2 V, 2.4 A, and 8 W may be supplied to the heater assembly  920 , but the present disclosure is not limited thereto. For example, when power is supplied to the heater assembly  920 , a surface temperature of a susceptor may rise to 400° C. or higher. The surface temperature of the susceptor may rise to approximately 350° C. before 15 seconds elapse from when power starts to be supplied to the heater assembly  920 . 
     The aerosol generating device  900  may include a separate temperature sensor. Alternatively, instead of including a separate temperature sensor, the heater assembly  920  may serve as a temperature sensor. Alternatively, while the heater assembly  920  serves as a temperature sensor, a separate temperature sensor may be further provided in the aerosol generating device  900 . 
     The processor  910  controls all operations of the aerosol generating device  900 . The processor  910  is an integrated circuit implemented as a processing unit such as a microprocessor and a microcontroller. 
     The processor  910  analyzes results sensed by the sensor  950  and controls subsequent processing to be performed. The processor  910  may start or stop supply of power from the battery  930  to the heater assembly  920  according to the sensed results. 
     In addition, the processor  910  may control the amount of power supplied to the heater assembly  920  and a time at which the power is supplied so that the heater assembly  920  is heated to a predetermined temperature or maintains an appropriate temperature. Furthermore, the processor  910  may process various types of input information and output information of the interface  960 . 
     The processor  910  may count the number of smoking by a user using the aerosol generating device  900  and control related functions of the aerosol generating device  900  to limit the user&#39;s smoking according to the counting result. 
     The memory  940 , as a hardware component configured to store various pieces of data processed in the aerosol generating device  900 , The memory  940  may store data processed or to be processed by the processor  910 . The memory  940  may include various types of memories; random access memory (RAM), such as dynamic random access memory (DRAM) and static random access memory (SRAM), etc.; read-only memory (ROM); electrically erasable programmable read-only memory (EEPROM), etc. 
     The memory  940  may store data about a user&#39;s smoking pattern such as smoking time and a smoking frequency. In addition, the memory  940  may store data related to a reference temperature change value when a cigarette is accommodated in an accommodation passage. 
     The battery  930  supplies power used to operate the aerosol generating device  900 . That is, the battery  930  may supply power to heat a susceptor. In addition, the battery  930  may supply power required for operations of other hardware, the processor  910 , the sensor  950 , and the interface  960  provided in the aerosol generating device  900 . 
     The battery  930  may be a lithium iron phosphate (LiFePO4) battery but is not limited thereto and may be manufactured as a lithium cobalt oxide (LiCoO2) battery, a lithium titanate battery, or so on. The battery  930  may be a rechargeable battery or a disposable battery. 
     The sensor  950  may include various types of sensors such as a puff detection sensor (temperature detection sensor, flow detection sensor, position detection sensor, or so on), a cigarette insertion detection sensor, and temperature detection sensor of a susceptor. Results sensed by the sensor  950  are transmitted to the processor  910 , and the processor  910  may control the aerosol generating device  900  so that various functions, such as control of a temperature of the heater assembly  920 , restriction of smoking, determination whether or not to insert a cigarette, and display of notification according to the sensed results, are performed. 
     The interface  960  may include various interfacing devices such as a display or lamp that outputs visual information, a motor that outputs tactile information, a speaker that outputs sound information, and terminals for data communication with input/output (I/O) interfacing units (for example, buttons and a touch screen) that receives information input by a user or outputs information to the user or terminals for receiving power, a communication interfacing module for performing wireless communication (for example, Wi-Fi, Wi-Fi direct, Bluetooth, near-field communication (NFC), and so on) with an external device. However, the aerosol generating device  900  may select some of the various interfacing devices exemplified above to perform. 
     Those of ordinary skill in the art related to the present embodiments may understand that various changes in form and details can be made therein without departing from the scope of the characteristics described above. The disclosed methods should be considered in a descriptive sense only and not for purposes of limitation. The scope of the present disclosure is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present disclosure.