Patent Publication Number: US-2022211895-A1

Title: Air sterilization device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0000941 filed in the Korean Intellectual Property Office on Jan. 5, 2021, and Korean Patent Application No. 10-2021-0075606 filed in the Korean Intellectual Property Office on Jun. 10, 2021, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The present disclosure relates to an air sterilization device. 
     (b) Description of the Related Art 
     Air cleaners in the related art are mostly mounted with H11 HEPA filters and purify air. The H11 HEPA filter has dust collecting efficiency of 95% based on a particle size of 0.3 um. However, because a size of a corona virus circulating worldwide in recent times is 0.08 to 0.1 um and smaller than a standard dust collecting size of the HEPA filter, the corona virus may pass through the HEPA filter. That is, the virus cannot be blocked only by the HEPA filter. 
     A sterilization method in the related art has been implemented by a catalyst reaction or an ozone reaction. However, because uniformity is hardly ensured in an effective sterilization region only by the catalyst reaction, there may be viruses that pass through the effective sterilization region without being sterilized. The ozone reaction is not appropriate to the daily life because of harmfulness of components thereof. 
     A UV lamp may more assuredly ensure a sterilization effect, but the technology related to the UV lamp is rejected because the UV lamp contains harmful substances such as mercury during a process of manufacturing the UV lamp. Some products perform the sterilization using UV LED light sources, but the UV LED light source is still insufficient to achieve the natural purpose of air sterilization. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in an effort to provide an air sterilization device capable of providing sterilizing power sufficient to remove harmful microorganisms as well as corona viruses. 
     An exemplary embodiment of the present invention provides an air sterilization device including a reflector, a first LED light source, and a second LED light source. The reflector may include a body part having a circular column shape having a vacant space therein and having openings formed in upper and lower surfaces thereof, a first rotary body connected to a lower surface of the body part and shaped to have a vacant space therein, and a second rotary body connected to an upper surface of the body part and shaped to have a vacant space therein; the first LED light source may emit UV-C rays in a direction from the first rotary body to the body part; and a second LED light source may emit UV-C rays in a direction from the second rotary body to the body part, and the reflector may reflect the light emitted from the first LED light source and the light emitted from the second LED light source. 
     The first rotary body may have a first opening that faces an opening through which the first rotary body and the lower surface of the body part are connected, and the first LED light source may be positioned correspondingly to the first opening. 
     The second rotary body may have a second opening that faces an opening through which the second rotary body and the upper surface of the body part are connected, and the second LED light source may be positioned correspondingly to the second opening. 
     A length in an extension direction of the body part and a radius of the body part may be set so that a residence time, which is a time for which air resides in the air sterilization device, is equal to or longer than a predetermined sterilization time. 
     The length in the extension direction of the body part and the radius of the body part may be set so that minimum illuminance required to ensure predetermined sterilizing power may be provided to the air sterilization device. The predetermined sterilization time may be 0.07 seconds, the minimum illuminance may be 43 mW/cm 2 , the length in the extension direction of the body part may be 80 mm to 120 mm, and the radius of the body part may be 25 mm to 35 mm. 
     A length of the first rotary body in a direction identical to an extension direction of the body part may be 5% to 15% of a length in an extension direction of the body part. 
     A length of the second rotary body in a direction identical to an extension direction of the body part may be 5% to 15% of a length in an extension direction of the body part. 
     An inclination angle of an inclined surface between a first opening of the first rotary body and an opening connected to the lower surface of the body part and facing the first opening may be 35 degrees to 55 degrees with respect to the lower surface of the body part. 
     An inclination angle of an inclined surface between a second opening of the second rotary body and an opening connected to the upper surface of the body part and facing the second opening may be 35 degrees to 55 degrees with respect to the upper surface of the body part. 
     The air sterilization device may further include a first heat sink coupled to the first LED light source; and a second heat sink coupled to the second LED light source. 
     The air sterilization device may further include a fan positioned on a lower portion of the first rotary body and configured to introduce air, in which the air introduced by the fan is introduced into the reflector through the first heat sink, passes through the body part, and is discharged to the outside of the reflector through the second heat sink. 
     Another exemplary embodiment of the present invention provides an air sterilization device including: a reflector implemented to have a shape made by coupling a body part and first and second rotary bodies coupled to two opposite surfaces of the body part, in which the body part has a vacant space therein, the first and second rotary bodies each have a vacant space therein, the first rotary body includes one surface connected to one of the two opposite surfaces of the body part, and the second rotary body includes one surface connected to the other of the two opposite surfaces of the body part. The air sterilization device may include a first LED light source positioned correspondingly to a first opening facing one surface of the first rotary body and configured to emit UV-C rays into the reflector; and a second LED light source positioned correspondingly to a second opening facing one surface of the second rotary body and configured to emit UV-C rays into the reflector. 
     A third opening facing the first opening may be formed in one surface of the first rotary body, and a fourth opening facing the second opening may be formed in one surface of the second rotary body. 
     The first LED light source may be positioned between the first opening and the third opening, and the second LED light source may be positioned between the second opening and the fourth opening. 
     The first and second LED light sources may be simultaneously turned on or only one of the first and second LED light sources may be turned on depending on a state of air. 
     The first and second LED light sources may be alternately turned off and on. 
     The present invention provides the air sterilization device capable of providing sterilizing power sufficient to remove harmful microorganisms as well as corona viruses. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view schematically illustrating an air sterilization device according to an embodiment. 
         FIG. 2  is a view schematically illustrating an air cleaning system according to the embodiment. 
         FIG. 3  is a view illustrating an air cleaner according to the embodiment. 
         FIG. 4  is a view illustrating a flow of air introduced and discharged by the air cleaner. 
         FIG. 5  is a view illustrating the air cleaner cut in half and opened with respect to A-A′ axis. 
         FIGS. 6 and 7  are views illustrating an upper coupling part in a right cross-section in  FIG. 5 . 
         FIG. 8  is a view illustrating the upper coupling part in a left cross-section in  FIG. 5 . 
         FIG. 9  is a cross-sectional view taken along line B-B′ and illustrating an upper structure of the air cleaner. 
         FIG. 10  is a view illustrating a heat sink coupled to the upper coupling part of the air cleaner when viewed from below to above in a z-axis direction. 
         FIG. 11  is a perspective view illustrating a state in which the upper coupling part, the heat sink, and an LED light source of the air cleaner are coupled when viewed from below. 
         FIG. 12  is a view illustrating a flow of air in the heat sink. 
         FIG. 13  is a view illustrating a flow of air in the upper coupling part. 
         FIG. 14  is a view schematically illustrating illuminance values in a cross-section perpendicular to a longitudinal direction of a reflector according to the embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The present invention relates to an air sterilization device using a UV LED light source and a reflector. Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings. The same or similar constituent elements are assigned with the same or similar reference numerals, and the repetitive description thereof will be omitted. The suffixes ‘module’, ‘unit’, ‘part’, and/or ‘portion’ used to describe constituent elements in the following description are used together or interchangeably in order to facilitate the description, but the suffixes themselves do not have distinguishable meanings or functions. In addition, in the description of the exemplary embodiment disclosed in the present specification, the specific descriptions of publicly known related technologies will be omitted when it is determined that the specific descriptions may obscure the subject matter of the exemplary embodiment disclosed in the present specification. In addition, it should be interpreted that the accompanying drawings are provided only to allow those skilled in the art to easily understand the exemplary embodiments disclosed in the present specification, and the technical spirit disclosed in the present specification is not limited by the accompanying drawings, and includes all alterations, equivalents, and alternatives that are included in the spirit and the technical scope of the present invention. 
     The terms including ordinal numbers such as ‘first’, ‘second’, and the like may be used to describe various constituent elements, but the constituent elements are not limited by the terms. These terms are used only to distinguish one constituent element from another constituent element. 
     When one constituent element is described as being “coupled” or “connected” to another constituent element, it should be understood that one constituent element can be coupled or connected directly to another constituent element, and an intervening constituent element can also be present between the constituent elements. When one constituent element is described as being “coupled directly to” or “connected directly to” another constituent element, it should be understood that no intervening constituent element is present between the constituent elements. 
     In the present application, it will be appreciated that terms “including” and “having” are intended to designate the existence of characteristics, numbers, steps, operations, constituent elements, and components described in the specification or a combination thereof, and do not exclude a possibility of the existence or addition of one or more other characteristics, numbers, steps, operations, constituent elements, and components, or a combination thereof in advance. 
     The embodiment of the present invention relates to an air sterilization device. For example, the air sterilization device includes an LED light source mounted in an air cleaner and configured to emit UV-C rays in a wavelength band of 100 to 280 nm instead of a catalyst or ozone reaction in the related art. The air passing through the interior of the air cleaner is irradiated directly with ultraviolet rays emitted from a UV-C LED light source, such that DNA or biological tissue of viruses, bacteria, and other harmful microorganisms contained in the air is destroyed and inactivated, thereby maintaining a user&#39;s health. The air sterilization device may be utilized by being mounted in the air cleaner or other small-sized portable products. For example, a small-sized air sterilization module may be manufactured and sized to be mounted in a small-sized or portable product, for example, an air cleaner, an AI speaker, a plant pot, a water tub, or the like and provide an air sterilization function. 
       FIG. 1  is a view schematically illustrating an air sterilization device according to an embodiment. 
     As illustrated in  FIG. 1 , an air sterilization device  200  includes two LED light sources  201  and  202  and a reflector  203 . The reflector  203  illustrated in  FIG. 1  includes a first rotary body  204 , a second rotary body  205 , and a body part  206  which is an effective sterilization region between the first rotary body  204  and the second rotary body  205 . The reflector  203  defines an internal space of the air sterilization device  200 . As illustrated in  FIG. 1 , UV-C rays are reflected in the internal space, thereby providing a sterilization action. 
     In  FIG. 1 , the two LED light sources  201  and  202  may each be implemented as a UV-C LED light source that makes an output of 10 mW or higher for the air sterilization. The two LED light sources  201  and  202  are disposed at two opposite ends of the reflector  203  so as to face each other. As described above, to achieve the air sterilization, the air sterilization device  200  according to the embodiment includes the reflector  203 , and the two UV-C LED light sources  201  and  202  disposed in the reflector  203  so as to face each other. 
     The reflector  203  may be made of aluminum capable of effectively reflecting the ultraviolet rays. The reflector  203  may be made of a material such as stainless steel (stainless use steel (SUS), aluminum, Teflon, and the like) which is not a perfect absorber. Aluminum may be effective in consideration of costs and UV-C reflectance. The reflector changes the direction of the light so that the light exiting the LED light sources  201  and  202  enters the air sterilization device  200  again to apply the UV-C rays to the sterilization function, thereby contributing to the sterilizing power. 
     The UV-C LED light sources  201  and  202  make an output of at least 10 mW or higher in order to ensure the sufficient sterilization effect. Each of the UV-C LED light sources  201  and  202  is positioned at one of two opposite ends of the effective sterilization region in the reflector  203 . The two UV-C LED light sources  201  and  202  are respectively positioned at positions corresponding to the two opposite ends of the effective sterilization region in the reflector  203  and disposed to face each other. A device for fixing the UV-C LED light sources  201  and  202  supports and fixes the UV-C LED light source. Electric wires and a temperature sensor for measuring a temperature may be provided on the device for fixing the UV-C LED light sources  201  and  202 . For example, the temperature sensor positioned on the device measures a temperature of a surface of the reflector  203 . It is possible to calculate and analogize temperatures of the UV-C LED light sources  201  and  202  by applying a regression equation to the measured temperature of the surface of the reflector. 
     Depending on a user&#39;s manipulation or distribution density of sterilization targets distributed in the air, the two LED light sources  201  and  202  may operate simultaneously or alternately or only the single LED light source may operate. 
     For example, in a case in which maximum sterilizing power needs to be ensured because a state of air measured by a dust sensor is very wrong, the two LED light sources  201  and  202  may be simultaneously turned on. When the state of air is good, one LED light source may be turned on, and the other LED light source may be turned off, thereby minimizing power consumption. Alternatively, from the state in which the first LED light source is turned on and the second LED light source is turned off, the first LED light source may be turned off and the second LED light source may be turned on, or the operation in the reverse order may be repeatedly performed, thereby minimizing a load applied to the LED light sources and minimizing the amount of heat generated from the LED light sources. The direct current (DC) voltage may be supplied to the LED light source to turn on the LED light source. Alternatively, the pulse voltage may be supplied to the LED light source, such that the LED light source may be repeatedly turned on and off. 
     The reflector  203  effectively disperses the ultraviolet rays generated therein, instead of light provided from the outside, without a missing part. The ultraviolet rays generated by the UV-C LED light source are reflected by the reflector  203 , such that the interior of the reflector  203  is densely filled with the ultraviolet rays without a missing part. Therefore, intensity of a critical dose or more of ultraviolet rays required for sterilization may be ensured in the reflector  203 . In addition, the two UV-C LED light sources, which are disposed to face each other, may ensure uniformity of intensity of the ultraviolet rays in the effective sterilization region in the reflector  203 . 
     The reflector  203  may be implemented by coupling the body part  206  and the first and second rotary bodies  204  and  205 . The body part  206  is provided in the form of a circular or polyhedral column having a vacant space therein, and the first and second rotary bodies  204  and  205  are disposed at two opposite ends of the body part  206  and each have a vacant space therein. An upper side of each of the first and second rotary bodies  204  and  205 , which is positioned toward the outside of the air sterilization device, may be opened. The first and second rotary bodies  204  and  205  each have a shape truncated at a particular position thereof in a direction perpendicular to an axial direction of a cone. Alternatively, the first and second rotary bodies  204  and  205  may each have a shape made by rotating an equilateral trapezoid about a centerline that connects a center of an upper side and a center of lower side of the equilateral trapezoid. Therefore, a lateral surface (hereinafter, referred to as an ‘inclined surface’) of each of the first and second rotary bodies  204  and  205  is inclined at a particular angle with respect to a reference plane (e.g., an upper surface or a lower surface of the body part). Hereinafter, an angle at which the lateral surface of the first and second rotary bodies  204  and  205  is inclined is referred to as an ‘inclination angle. Air is introduced into the reflector  203  through the opening of one of the first and second rotary bodies  204  and  205  and discharged to the outside through the opening of the other of the first and second rotary bodies  204  and  205 . The interior of the reflector  203  may be made of a material capable of reflecting the ultraviolet rays, and a ratio between lengths B 2  and B 3  of the rotary bodies and a length B 1  of the body part may be calculated depending on a field of view (FOV) of the LED light sources. The ultraviolet rays emitted from the LED light sources may be effectively dispersed depending on this ratio, thereby ensuring sterilizing power and uniformity for a target. The inclination angle is defined as an angle within a predetermined range based on the FOV of the LED light source, such that the components of the ultraviolet rays, which scatter backward, may be reflected and returned back to the effective sterilization region. 
       FIG. 2  is a view schematically illustrating an air cleaning system according to the embodiment. 
     As illustrated in  FIG. 2 , a plurality of air sterilization devices is arranged to provide large-scale air sterilization. 
       FIG. 3  is a view illustrating an air cleaner according to the embodiment.  FIG. 3  is a view illustrating an interior of an air cleaner  1  by cutting a predetermined part of the air cleaner  1  for clearly explaining a structure of an air sterilization device  10 . 
     The air sterilization device  10  includes a reflector  100 , heat sinks  110  and  130 , and LED light sources  120  and  140 . The reflector  100  includes a first rotary body  101 , a first opening  102 , a body part  103 , a second rotary body  104 , and a second opening  105 . The first rotary body  101 , the body part  103 , and the second rotary body  104  may each be made of aluminum having a reflection function. 
     The body part  103  has a circular column shape having a vacant space therein and openings formed in upper and lower surfaces thereof. 
     Substantially, the upper and lower surfaces of the body part  103  may each include an opened region which is the entire region except for a rim region defined by a thickness of a lateral surface of the body part  103 . The first rotary body  101  has a first opening  102 , and the first rotary body  101  includes an upper surface that is connected to and in contact with a lower surface of the body part  103 . The upper surface of the first rotary body  101  may have an opening  191  that is the entire region except for the rim region defined by a thickness of the inclined surface of the first rotary body  101 . The second rotary body  104  has a second opening  105 , and the second rotary body  104  includes a lower surface that is connected to and in contact with an upper surface of the body part  103 . The lower surface of the second rotary body  104  may include an opening  192  which is the entire region except for the rim region defined by a thickness of the inclined surface of the second rotary body  104 . 
     As illustrated in  FIG. 3 , the air cleaner  1  includes the air sterilization device  10 , and a housing  2  that accommodates the air sterilization device  10 . The housing  2  may include an air inflow part  20 , a lower coupling part  30 , a body cover part  40 , and an upper coupling part  50 . The lower coupling part  30  is coupled to the first rotary body  101  by means of a fastening means and fixes and supports the reflector  100 . The upper coupling part  50  is coupled to the second rotary body  104  by means of a fastening means and fixes and supports the reflector  100 . The body cover part  40  is disposed between the upper coupling part  50  and the lower coupling part  30  and surrounds the body part  103  of the reflector  100 . The housing  2  has a circular column shape as a whole, but the present invention is not limited thereto. The air sterilization device has a shape including a circular column, and thus the housing  2  has a circular column shape as a whole. However, when the air sterilization device has a polyhedral column shape, the body cover part  40  of the housing  2  may at least have a polyhedral column shape. A lower structure  20  may have a circular column shape having a plurality of holes through which the outside air is introduced. An upper surface of the lower structure  20  has a circular opening  21  in which a fan  60  is positioned, and the fan  60  is coupled to a lower end of the circular opening  21 . The outside air is introduced by the fan  60  and flows upward. 
     The LED light source  120  coupled to the heat sink  110  is positioned in the first opening  102  formed in the lower surface of the first rotary body  101  positioned at one end of the reflector  100 . The LED light source  140  coupled to the heat sink  130  is positioned in the second opening  105  formed in the upper surface of the second rotary body  104  positioned at the other end of the reflector  100 . A side of the LED light source  120 , from which the light is radiated, may be positioned in a region defined by the length B 2  of the first rotary body  101 , and a side of the LED light source  140 , from which the light is radiated, may be positioned in a region defined by the length B 3  of the second rotary body  104 . 
     The air introduced by the fan  60  is introduced into the reflector  100  through the heat sink  110 , passes through the body part  103 , and is discharged to the outside of the reflector  100  through the heat sink  130 . A plurality of discharge ports is formed in an upper surface of the upper coupling part  50  positioned at the upper side of the reflector  100  so that the air may be discharged through the plurality of discharge ports. The discharge ports illustrated in  FIG. 3  are each provided in the form of a circular band, but the present invention is not limited to this example. 
       FIG. 4  is a view illustrating a flow of air introduced and discharged by the air cleaner. 
       FIG. 5  is a view illustrating the air cleaner cut in half and opened with respect to A-A′ axis. 
       FIGS. 6 and 7  are views illustrating the upper coupling part in the right cross-section in  FIG. 5 . 
       FIG. 8  is a view illustrating the upper coupling part in the left cross-section in  FIG. 5 . 
     As illustrated in  FIGS. 6 and 7 , a cap  51  is a part of an upper coupled part  50  which is inclined at an angle corresponding to the second rotary body  104 . h 1  represents a length of a connection part  106  of the second rotary body  104  connected to a connection part  511  of the cap  51  by means of a fastening means and may be set to a length in a z-axis direction of the second rotary body  104 . h 2  represents a length of the connection part  511  extending downward in the z-axis direction from a lower surface of the cap  51  and may be set to a length in the z-axis direction of the cap  51 . 
     h 1  and h 2  are fixed. Lengths in the z-axis direction of bridges  131  and  132  of the heat sink  130  are determined depending on a position of a light-emitting surface of the LED light source  140 . For example, a light-emitting part of the LED light source  140  may be positioned in a range of distance d 2  from a line L 1  to a line L 2 . Then, a difference between a minimum value and a maximum value of a length h 3  in the z-axis direction of the bridge  131  may be d 2 . In  FIG. 6 , a position of the light-emitting part of the LED light source  140  is adjacent to the line L 1 . In  FIG. 7 , a position of the light-emitting part of the LED light source  140  is adjacent to line L 2 . A difference between the length h 3  in the z-axis direction of the bridge  131  illustrated in  FIG. 6  and a length h 3 ′ in the z-axis direction of the bridge  131  illustrated in  FIG. 7  may be a difference between the position of the light-emitting part of the LED light source  140  illustrated in  FIG. 6  and the position of the light-emitting part of the LED light source  140  illustrated in  FIG. 7 . 
     Further, in the air sterilization device  10 , the positions of the two heat sinks  110  and  130 , the positions of the two LED light sources  120  and  140 , and the positions of the first and second rotary bodies  101  and  104  may be symmetric with respect to the center of the air sterilization device  10 . 
     In addition, in  FIGS. 5, 6, and 7 , a ratio between a length d 1  in the z-axis direction of the body part  103  and a length d 2  in the z-axis direction of the second rotary body  104  may be set to approximately 10:1. 
       FIG. 9  is a cross-sectional view taken along line B-B′ and illustrating the upper structure of the air cleaner. 
       FIG. 10  is a view illustrating the heat sink coupled to the upper coupling part of the air cleaner when viewed from below to above in the z-axis direction. 
     As illustrated in  FIG. 10 , the three bridges  131 ,  132 , and  133  extending from the main body of the heat sink  130  are partially positioned between the three connection parts  511  and  512  in  FIGS. 7 and 513  in  FIG. 8  extending downward in the z-axis direction from the lower surface of the cap  51  and the three connection parts  106 ,  107 , and  108  extending upward in the z-axis direction from the upper surface of the second rotary body  104 . The connection part of the cap  51 , the bridge, and the connection part of the second rotary body  104  are coupled and fixed by fastening means (e.g., screws). 
     A coupling structure between the lower coupling part  30  and the first rotary body  101  is similar to the above-mentioned coupling structure between the upper coupling part  50  and the second rotary body  104 . 
       FIG. 11  is a perspective view illustrating a state in which the upper coupling part, the heat sink, and the LED light source of the air cleaner are coupled when viewed from below. 
       FIG. 12  is a view illustrating a flow of air in the heat sink. 
     As illustrated in  FIG. 12 , the heat sink  130  has a plurality of fins (e.g.,  135 ) extending in the z-axis direction from a lower structure  134 . Then, wind passes through the heat sink  130  in all directions, thereby facilitating cooling. Further, the bridges  131 ,  132 , and  133  extend from the lower structure  134 . 
       FIG. 13  is a view illustrating a flow of air in the upper coupling part. As illustrated in  FIG. 13 , it can be seen that the air, which is discharged to a portion between the second rotary body  104  and the heat sink  130  is cooled by flowing into the heat sink  130 . 
     The use of the present invention may establish the sterilization system capable of directly sterilizing the air and substantially removing corona viruses and other harmful microorganisms. The air sterilization device may be mounted in an air cleaner in the related art to develop the product capable of simultaneously removing fine dust and viruses. Alternatively, the air sterilization device may be mounted in the air cleaner using the advantage of the small-sized air sterilization device according to the present invention even though the product is not used for the purpose of sterilization. For example, the present module may be mounted in a predetermined space inside or outside a plant pot disposed for the purpose of indoor interior design, thereby obtaining the air sterilization effect. 
     The viruses such as COVID-19 may be sterilized by a smaller dose than colon bacilli. 1.89 dose is required for 99.99% sterilization of general colon bacilli. However, in the case of COVID-19, 99.9% sterilization is enabled at a level of 50% of colon bacillus sterilizing power. The sterilizing power of 3 doses or more needs to be ensured to prevent virus infection through the air that may occur in the future in addition to COVID-19. 
     The present embodiment may provide the compact air sterilization device that instantaneously provides the sterilizing power of 3 doses. To this end, optimized design is required for the LED light source and reflector structure of the air sterilization device. The following examples are provided to explain the present invention and does not limit the protection scope of the present invention. 
     When the length B 1  of the body part, which corresponds to the length of the air sterilization device, decreases to miniaturize the air sterilization device, the miniaturization may be implemented, but the distance between the LED light sources decreases. In this case, heat generated from one LED light source affects the other LED light source, which affects the durability and reliability of the LED light source. In this case, the output of the LED light source decreases, which may cause a reduction in sterilizing power and a deterioration in performance of the air sterilization device. 
     In addition, the air sterilization device may be miniaturized by decreasing a diameter (B 11  or B 12  in  FIG. 1 ) of the air sterilization device to miniaturize the air sterilization device. However, the time for which the air resides in the air sterilization device becomes shorter than the sterilization time required to ensure 99.9% sterilizing power. To ensure the sterilizing power while reducing the size of the air sterilization device, the time for which the air resides in the air sterilization device needs to be equal to or longer than a predetermined sterilization time (e.g., the sterilization time required to ensure 99.9% sterilizing power. In addition, minimum illuminance required to ensure 99.9% sterilizing power needs to be provided to the air sterilization device. 
     In the following description, various examples of the air sterilization device, which may minimize the size of the air sterilization device while satisfying the sterilizing power of 99.9% will be described. For example, to provide a function of performing 99.9% sterilization when the air passes through the air sterilization device  200  once, the air sterilization device  200  may be designed to satisfy a condition in which the minimum residence time of the air is 0.07 seconds and the minimum illuminance in the air sterilization device  200  is 43 mW/cm 2 . The residence time refers to the time for which the air is introduced into one side of the air sterilization device  200  and discharged from the other side of the air sterilization device  200  in an ideal equilibrium state. That is, the residence time refers to the time for which the air passes through the interior of the air sterilization device  200 . The minimum residence time may be set to 0.07 seconds. The minimum illuminance means the lowest illuminance in respect to intensity of the light emitted for each unit area in the air sterilization device  200 . A critical value of the minimum illuminance may be 43 mW/cm 2 . The minimum dose may be set to 3 mJ, i.e., a value made by multiplying the minimum residence time by the critical value of the minimum illuminance (0.07 seconds*43 mW/cm 2 ). When the minimum residence time increases or the minimum illuminance increases, the sterilizing power may increase as the minimum illuminance increases. 
     The residence time and the minimum illuminance value may be derived by flow analyses and optical simulations. 
     Table 1 shows the length B 1  and ½ of B 11  and B 12  that satisfy the minimum residence time of 0.07 seconds. 
     
       
         
           
               
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Residence 
                 Radius of body part (½ of 
               
               
                 time for each 
                 B11 and B12) [mm] 
               
            
           
           
               
               
               
               
               
               
            
               
                 condition (sec.) 
                 15 
                 20 
                 25 
                 30 
                 35 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 Length 
                  50 
                 0.02 
                 0.03  
                 0.04 
                 0.06 
                 0.08 
               
               
                 of body 
                  60 
                 0.02 
                 0.03  
                 0.05 
                 0.07 
                 0.10 
               
               
                 part (B1) 
                  70 
                 0.02 
                 0.04  
                 0.06 
                 0.09 
                 0.12 
               
               
                 [mm] 
                  80 
                 0.02 
                 0.04  
                 0.07 
                 0.10 
                 0.13 
               
               
                   
                  90 
                 0.03 
                 0.05  
                 0.08 
                 0.11 
                 0.15 
               
               
                   
                 100 
                 0.03 
                 0.05  
                 0.09 
                 0.12 
                 0.17 
               
               
                   
                 110 
                 0.03 
                 0.06  
                 0.09 
                 0.14 
                 0.18 
               
               
                   
                 120 
                 0.04 
                 0.066 
                 0.10 
                 0.15 
                 0.20 
               
               
                   
               
            
           
         
       
     
     However, in Table 1, when the length B 1  of the body part is short (e.g., shorter than 80 mm), the distance between the two LED light sources  201  and  202 , which is the light sources, is too short. Therefore, the two LED light sources  201  and  202  affect each other in terms of reliability and durability of the light sources. This may cause a deterioration in sterilizing power. In addition, to miniaturize the air sterilization device  200 , the length B 1  of the body part is set to 120 mm or less, and the radius (½ of B 11  and B 12 ) of the body part is set to 35 mm or less. Therefore, referring to Table 1, to satisfy the miniaturization and the minimum residence time, the length B 1  of the body part may be designed in a range of 80 mm to 120 mm, and the radius (½ of B 11  and B 12 ) may be designed in a range of 25 mm to 35 mm. 
     Table 2 shows minimum illuminance and doses in the air sterilization device  200  under the structural conditions of the air sterilization device shown in Table 1. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
             
            
               
                 Reference 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 residence 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
            
           
           
               
               
               
            
               
                 time 
                 0.07 
                 Radius of body part (½ of B11 and B12) [mm] 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Minimum 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
               
                 target 
                   
                   
                   
                   
                   
                   
                   
                   
                   
                   
               
            
           
           
               
               
               
               
               
            
               
                 illuminance 
                 43 
                 15 
                 20 
                 25 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
               
            
               
                 Minimum 
                   
                 Residence 
                 Minimum 
                   
                 Residence 
                 Minimum 
                   
                 Residence 
                 Minimum 
                   
               
               
                 target dose 
                 3.01 
                 time 
                 illuminance 
                 Dose 
                 time 
                 illuminance 
                 Dose 
                 time 
                 illuminance 
                 Dose 
               
               
                   
               
               
                 Length of 
                 50 
                 0.02 
                 90.09 
                 1.38 
                 0.03 
                 74.08456 
                 2.02 
                 0.04 
                 46.33923 
                 1.98 
               
               
                 body 
                 60 
                 0.02 
                 87.73 
                 1.62 
                 0.03 
                 69.91362 
                 2.29 
                 0.05 
                 45.52792 
                 2.33 
               
               
                 part (B1) 
                 70 
                 0.02 
                 87.89 
                 1.89 
                 0.04 
                 70.59217 
                 2.70 
                 0.06 
                 46.11983 
                 2.75 
               
               
                 [mm] 
                 80 
                 0.02 
                 90.50 
                 2.22 
                 0.04 
                 70.16261 
                 3.07 
                 0.07 
                 46.74986 
                 3.19 
               
               
                   
                 90 
                 0.03 
                 86.43 
                 2.39 
                 0.05 
                 67.89755 
                 3.34 
                 0.08 
                 45.90056 
                 3.52 
               
               
                   
                 100 
                 0.03 
                 85.7887 
                 2.64 
                 0.05 
                 65.96786 
                 3.60 
                 0.09 
                 44.57061 
                 3.80 
               
               
                   
                 110 
                 0.03 
                 83.25767 
                 2.81 
                 0.06 
                 62.5933 
                 3.76 
                 0.09 
                 42.74401 
                 4.01 
               
               
                   
                 120 
                 0.04 
                 79.949 
                 2.95 
                 0.07 
                 59.5764 
                 3.90 
                 0.10 
                 40.87657 
                 4.19 
               
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Reference 
                   
                   
                   
                   
                   
                   
               
               
                   
                 residence 
                   
                   
                   
                   
                   
                   
               
            
           
           
               
               
               
            
               
                   
                 time 
                 Radius of body part (½ of B11 and B12) [mm] 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Minimum 
                   
                   
                   
                   
                   
                   
               
               
                   
                 target 
                   
                   
                   
                   
                   
                   
               
            
           
           
               
               
               
               
            
               
                   
                 illuminance 
                 30 
                 35 
               
            
           
           
               
               
               
               
               
               
               
               
            
               
                   
                 Minimum 
                 Residence 
                 Minimum 
                   
                 Residence 
                 Minimum 
                   
               
               
                   
                 target dose 
                 time 
                 illuminance 
                 Dose 
                 time 
                 illuminance 
                 Dose 
               
               
                   
               
               
                   
                 Length of 
                 0.06 
                 40.21906 
                 2.47 
                 0.06 
                 31.83908 
                 2.66 
               
               
                   
                 body 
                 0.07 
                 38.24287 
                 2.82 
                 0.10 
                 30.74466 
                 3.09 
               
               
                   
                 part (B1) 
                 0.09 
                 36.47883 
                 3.14 
                 0.12 
                 31.55007 
                 3.69 
               
               
                   
                 [mm] 
                 0.10 
                 38.23582 
                 3.76 
                 0.13 
                 32.18431 
                 4.31 
               
               
                   
                   
                 0.11 
                 36.84734 
                 4.07 
                 0.15 
                 31.45101 
                 4.73 
               
               
                   
                   
                 0.12 
                 35.56351 
                 4.37 
                 0.17 
                 30.00329 
                 5.02 
               
               
                   
                   
                 0.14 
                 33.55328 
                 4.53 
                 0.18 
                 27.38982 
                 5.04 
               
               
                   
                   
                 0.15 
                 32.35319 
                 4.77 
                 0.20 
                 25.96985 
                 5.21 
               
               
                   
               
            
           
         
       
     
     As can be seen in Table 2, when the length B 1  of the body part is 60 mm and the radius (½ of B 11  and B 12 ) of the air sterilization device is 35 mm, the reference minimum dose is satisfied. When the length B 1  of the body part is 70 mm and the radius (½ of B 11  and B 12 ) of the air sterilization device is in a range of 30 mm to 35 mm, the reference minimum dose is satisfied. When the length B 1  of the body part is 80 to 120 mm and the radius (½ of B 11  and B 12 ) of the air sterilization device is in a range of 20 mm to 35 mm, the reference minimum dose is satisfied. 
     Therefore, it can be seen that the design conditions of the minimum illuminance and the minimum residence condition described with reference to Table 1 are also satisfied. 
     The rotary bodies  204  and  205  serve to reflect the light emitted from the LED light sources  201  and  202  and transmit the light into the reflector  100 . The light reflected by the rotary bodies  204  and  205  may contribute to the sterilization. 
     The shape of each of the rotary bodies  204  and  205  is related to the residence time for which the air resides in the internal space of the reflector  100 . For example, the lengths B 3  and B 2  and the inclination angle of the rotary bodies  204  and  205  need to be designed so as not to reduce the residence time. For example, each of the lengths B 3  and B 2  of the rotary bodies  204  and  205  may be appropriately designed to have a length that is 10% of the length B 1  of the body part. To cope with an assembly error and a change in residence time due to the assembly error, each of the lengths B 3  and B 2  of the rotary bodies  204  and  205  may be designed within a range of 5% to 15% of the length B 1  of the body part. 
     Further, an inclination angle θ needs to be designed to have a value larger than 0 degree. The inclination angle θ may be designed to ensure the minimum residence time in consideration of the change in residence time in accordance with the inclination angle θ of each of the rotary bodies  204  and  205 . The inclination angle θ may be designed to be 45 degrees in consideration of the probability of the light contributing to the sterilization in the reflector  100 . The light emitted from the LED light sources  201  and  202  is reflected by the inclined surfaces of the rotary bodies  204  and  205 , such that a direction vector of the light may be changed to a direction vector of the light perpendicular to the optical axis. The optical axis is the direction indicated by the arrows in  FIG. 1 . Therefore, the number of light beams, which are reflected by the inclined surfaces of the rotary bodies  204  and  205  and introduced into the reflector  100  among the light beams emitted from the LED light sources  201  and  202 , is increased. The light beams entering the reflector  100  may contribute to the sterilization. The inclination angle θ may be designed with a margin of +/−10 degrees with respect to an angle of 45 degrees to correct the assembly tolerance and the system. 
     In the embodiment, the inclination angle has been described as 45 degrees, but the present invention is not limited thereto. The inclination angle may vary depending on the structure of the reflector  100 , the lengths B 2  and B 3  of the rotary body, the length B 1  of the body part, and the like. The light emitted from the LED light source may contribute directly to the sterilization in the reflector  100 , and the light radiated from the LED light source may be reflected by the rotary body, thereby contributing to the sterilization. The inclination angle of the rotary body may be set such that a degree of the contribution to the sterilization by the reflection of the light emitted from the LED light source is maximized. 
       FIG. 14  is a view schematically illustrating illuminance values in a cross-section perpendicular to a longitudinal direction of the reflector according to the embodiment. 
     When the illuminance value illustrated in  FIG. 14  is multiplied by the residence time in the reflector  100 , the illuminance at the outermost periphery (the outermost periphery of the circular region illustrated in  FIG. 14 ) of the reflector  100  is 40 mW/cm 2 . The residence time in the reflector  100  according to the embodiment, which is calculated depending on the flow analysis, is approximately 0.1208 seconds. Therefore, an approximate dose at the outermost periphery in the reflector  100  is 4.9529 [dose].  FIG. 14  schematically illustrates that the illuminance value is an illuminance value in the reflector  100  when the inclination angle of the rotary body is 45 degrees, the length of the body part is 120 mm, and the length of the rotary body is 12 mm. The length of the rotary body corresponds to 10% of the length of the body part. 
     While the embodiments of the present invention have been described in detail above, the protection scope of the present invention is not limited thereto, various alterations and modifications may be made by those skilled in the art, and these alterations and modifications belong to the protection scope of the present invention. 
     DESCRIPTION OF SYMBOLS 
     
         
         
           
               1 : Air cleaner 
               10 ,  200 : Air sterilization device