Patent Publication Number: US-10330303-B2

Title: Light emitting device module with heat-sink and air guide

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the priority benefit of Korean Patent Application No. 10-2013-0141053, filed on Nov. 20, 2013 and Korean Application No. 10-2013-0144031 filed on Nov. 25, 2013 in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments relate to a module array and a lighting apparatus having the same. 
     2. Description of the Related Art 
     In general, bulbs or fluorescent lamps are frequently used for indoor or outdoor lighting. These bulbs or fluorescent lamps problematically require frequent replacement due to a relatively short lifespan thereof. In addition, conventional fluorescent lamps deteriorate over time, thus suffering from a gradual reduction in the intensity of illumination. 
     To solve the above problems, various shapes of lighting modules using Light Emitting Diodes (LEDs) have been developed because light emitting diodes exhibit excellent control efficiency, rapid responsiveness, high photoelectric conversion efficiency, long lifespan, low power consumption and high brightness and may be used to provide mood lighting. 
     Light emitting diodes are semiconductor devices that convert electric energy into light. Such light emitting diodes have several advantages, such as low power consumption, semipermanent lifespan, rapid responsiveness, safety and eco-friendly properties, as compared to conventional light sources, such as fluorescent lamps, incandescent bulbs, etc. For this reason, replacement of conventional light sources with light emitting diodes is being performed, and light emitting diodes are increasingly being used as light sources of indoor and outdoor lighting devices, such as various liquid crystal display devices, electronic display boards, street lights, etc. 
     Such light emitting devices are fabricated in the form of a light emitting device module for convenience of assembly and protection against external shock and moisture. 
     The light emitting device module, however, problematically generates extreme heat due to high integration density of light emitting devices. 
     SUMMARY OF THE INVENTION 
     Embodiments herein provide a module array and a lighting apparatus having the same, which may effectively radiate heat generated from light emitting devices. 
     In one embodiment, a module array includes at least one light emitting device module, wherein the light emitting device module includes a light source unit, a body provided at one surface thereof with a seat on which the light source unit is seated, a plurality of radiation fins disposed on the other surface of the body opposite to one surface of the body, and an air hole perforated in the body from the seat to the radiation fins for the flow of air. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  is a perspective view of a module array according to one embodiment of the present invention; 
         FIG. 2  is a lower side view of the module array shown in  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a light emitting device module according to a first embodiment; 
         FIG. 4  is a front view of the light emitting device module according to the first embodiment; 
         FIG. 5 a    is a side view and  FIG. 5 b    is an upper side view of the light emitting device module according to the first embodiment; 
         FIG. 6  is a view showing the velocity distribution of air in the light emitting device module according to the first embodiment; 
         FIG. 7  is a lower side view of a module array according to another embodiment of the present invention; 
         FIG. 8  is an exploded perspective view of a light emitting device module according to a second embodiment; 
         FIG. 9  is an exploded perspective view of a light emitting device module according to a third embodiment; and 
         FIG. 10  is a perspective view of a lighting apparatus including light emitting device modules according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Advantages and features of the present invention and a method of achieving the same will be more clearly understood from embodiments described below with reference to the accompanying drawings. However, the present invention is not limited to the following embodiments but may be implemented in various different forms. The embodiments are intended merely to provide a complete disclosure of the present invention to a person having ordinary skill in the art to which the present invention pertains. The scope of the invention is intended to be defined only by the claims. Wherever possible, the same reference numbers will be used throughout the specification to refer to the same or like parts. 
     In addition, angles and directions referred to during the description of a structure of an embodiment are described based on illustration in the drawings. In the description of the structure of the embodiment, if reference points with respect to the angles and positional relations are not clearly stated, the related drawing will be referred to. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Hereinafter, the embodiments will be described in detail with reference to the drawings. 
       FIG. 1  is a perspective view of a module array according to one embodiment of the present invention,  FIG. 2  is a lower side view of the module array shown in  FIG. 1 ,  FIG. 3  is an exploded perspective view of a light emitting device module according to a first embodiment,  FIG. 4  is a front view of the light emitting device module according to the first embodiment, and  FIG. 5 a    is a side view and  FIG. 5 b    is an upper side view of the light emitting device module according to the first embodiment. 
     The module array according to one embodiment, designated by reference numeral  200 , includes a single light emitting device module  100 , or includes at least two light emitting device modules  100  arranged in combination with each other. For example, the module array  200  may include four light emitting device modules  100 - 1 ,  100 - 2 ,  100 - 3  and  100 - 4 , arranged as shown in  FIGS. 1 and 2 . The light emitting device module  100  constituting the module array  200  will first be described below. 
     Referring to  FIGS. 3 to 5   b , the light emitting device module  100 , which constitutes the module array  200 , may include a light source unit  110 , a body  120  provided at one surface thereof with a seat  121  on which the light source unit  110  is seated, and a plurality of radiation fins  130  arranged at the other surface of the body  120  opposite to the one surface of the body  120  provided with the seat  121 . 
     In addition, the light emitting device module  100  may include an air hole  122  perforated in the body  120  from the seat  121  to the radiation fins  130  for the flow of air. 
     The light source unit  110  may include various types of devices for the generation of light. 
     The light source unit  110  includes a board  112  and light emitting devices  111  disposed on the board  112 , the light emitting devices  111  being electrically connected to the board  112 . 
     The board  112  is disposed on one surface of the body  120 . The board  112  takes the form of a rectangular board corresponding to one surface of the body  120 , without being limited thereto. For example, the board  112  may have one of various shapes, such as a polygonal shape, an oval shape, etc. The board  112  may include a circuit pattern printed on an insulator. For example, the board  112  may be a general Printed Circuit Board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB or the like. 
     The light source unit  110  may be Chip On Board (COB) to which LED chips can be directly bonded, rather than being packaged on a printed circuit board. The COB is formed of ceramic, thus achieving heat resistance and electrical insulation. 
     An upper surface of the board  112  may be coated with a material capable of efficiently reflecting light. For example, the upper surface of the board  112  may be coated with a white or silvery material. 
     A single light emitting device or a plurality of light emitting devices  111  may be arranged. In addition, in the case of arrangement of the plurality of light emitting devices  111 , the respective light emitting devices  111  may emit different colors of light, or may exhibit different color temperatures. 
     The light source unit  110  may be disposed on the seat  121  formed at one surface of the body  120  and be supported by the body  120 . The seat  121  may be indented in one surface of the body  120 , and the board  112  may have a shape corresponding to the shape of the seat  121  so as to be inserted into the seat  121 . 
     The board  112  may have a board hole  113  communicating with the air hole  122 . The board hole  113  is positioned to overlap the air hole  122  in the vertical direction (in the Y-axis) and is in communication with the air hole  122  to provide an air flow space. 
     Here, the term “vertical” is not limited to completely vertical (90 degrees to a horizontal X-axis), but instead may include a range of angular deviation (for example 45 degrees) from completely vertical without departing from the scope of the invention. 
     The light emitting devices  111  on the board  112  may be arranged to surround the board hole  113 . More specifically, the board hole  113  may be perforated in the board  112  in the Y-axis, and the light emitting devices  111  may be arranged around the board hole  113  in the X-Z plane. 
     A heat radiation pad  150  may be additionally provided between the board  112  and the seat  121  for enhancement of heat transfer. The heat radiation pad  150  may have a shape corresponding to the seat  121  and may be formed of a material having excellent heat transfer and adhesion properties. For example, the heat radiation pad  150  may be formed of silicon. The heat radiation pad  150  may be a film and have a pad hole  153  communicating with the air hole  122 . 
     The light emitting device module  100  may further include a plurality of lenses  141  which shield the light emitting devices  111  and refract light emitted from the light emitting devices  111 . The lenses  141  function to diffuse light emitted from the light emitting devices  111 . A diffusion angle of light emitted from the light emitting devices  111  may be determined based on the shape of the lenses  141 . For example, the lenses  141  may allow the light emitting devices  111  to be molded in a convex form. 
     The lenses  141  may be formed of a light transmitting material. For example, the lenses  141  may be formed of transparent silicon, epoxy and one or more various other resins. 
     In addition, each lens  141  may be positioned to enclose the light emitting device  111  to isolate the light emitting device  111  from the outside, in order to protect the light emitting device  111  from external moisture and shock. 
     For convenience of assembly, the lenses  141  may be disposed on a lens cover  142  having a shape corresponding to the shape of the board  112 . The lens cover  142  may be formed to correspond to the board  112 , and the lenses  141  on the lens cover  142  may be positioned to overlap the respective light emitting devices  111 . The lens cover  142  may have a cover hole  143  communicating with the air hole  122 . 
     The lenses  141  may be integrated with the lens cover  142  to enable easy assembly of the lenses  141  that shield the respective light emitting devices  111 . In this case, the cover hole  143  assists positional alignment of the lens cover  142  and provides a flow space of air for passage through the air hole  122 . More specifically, the cover hole  143  may be perforated in the center of the lens cover  142  in the vertical direction (in the Y-axis). The cover hole  143  may be positioned to correspond to the air hole  122 . The cover hole  143  serves as a space for radiation of heat from the lens cover  142 . 
     The body  120  provides a seating space for the light source unit  110  and transfers heat generated in the light source unit  110  to the radiation fins  130 . 
     To enhance heat transfer efficiency, the body  120  may be formed of a metal material or a resin material having excellent heat radiation efficiency, without being limited thereto. 
     For example, a constituent material of the body  120  may include at least one of aluminum (Al), nickel (Ni), copper (Cu), silver (Ag) and tin (Sn). In addition, the body  120  may be formed of at least one of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide9T (PA9T), new geo tactics polystyrene (SPS), a metal material, sapphire (Al2O3), beryllium oxide (BeO) and ceramic. The body  120  may be formed by injection molding, etching, etc., without being limited thereto. 
     The body  120  may be provided at one surface thereof with the seat  121  on which the light source unit  110  is seated and at the other surface thereof with the radiation fins  130 . The body  120  may take the form of a rectangular plate having a plane (the X-Z plane). 
     The seat  121  may be indented in one surface (for example, an upper surface) of the body  120  and have a shape corresponding to the shape of the board  112 . 
     Screw holes  126  may be formed in corners of the body  120  such that screws are fastened through the screw holes  126  for coupling the body  120  to a lighting apparatus, for example. 
     Referring to  FIG. 4 , the radiation fins  130  may have a shape to maximize an air contact area thereof. Specifically, the radiation fins  130  may take the form of a plurality of plates extending downward (i.e. in the Y-axis direction) from the other surface (for example, a lower surface) of the body  120 . More specifically, the radiation fins  130  may be arranged at a constant pitch, and the width of the respective radiation fins  130  may be equal to the width of the body  120  for effective transfer of heat from the body  120  to the radiation fins  130 . 
     The radiation fins  130  may be integrally molded with the body  120 , or may be fabricated as separate elements. The radiation fins  130  may be formed of a material having high heat transfer efficiency, for example, at least one of aluminum (Al), nickel (Ni), copper (Cu), silver (Ag) and tin (Sn). 
     Referring to  FIGS. 4, 5   a  and  5   b , the radiation fins  130  may be elongated in the transverse direction of the body  120  (in the X-axis) and may be arranged at a constant pitch in the longitudinal direction of the body  120  (in the Z-axis). 
     A center portion  131  of each radiation fin  130  may be indented toward the body  120  from both end portions  133  of the radiation fan  130 . Since both end portions  133  of the radiation fin  130  vertically overlap the light emitting devices  111 , the end portions  133  of the radiation fin  130  may have a greater height than that of the center portion  131  of the radiation fin  130  to achieve an increased air contact area. Moreover, the indented center portion  131  of the radiation fin  130  may provide reduced manufacturing costs. 
     Referring again to  FIGS. 1 and 3 , the air hole  122  is perforated in the body  120  from the seat  121  to the radiation fins  130  (in the Y-axis) to provide an air flow space. The air hole  122  may be perforated in the central region of the body  120  so as to extend by a long length in the longitudinal direction of the body  120 . 
     The air hole  122  may vertically overlap the board hole  113  perforated in the board  112 , the cover hole  143  perforated in the lens cover  142  and the pad hole  153  perforated in the heat radiation pad  150  and communicate with the same. 
     As air flows through the air hole  122  by a temperature difference between the exterior and the interior of the air hole  122 , cooling of the radiation fins  130  and the body  120  may be accelerated. 
     Specifically, the air hole  122  may vertically overlap the center portion  131  of the respective radiation fins  130  and the light emitting devices  111  may vertically overlap both end portions  133  of the respective radiation fins  130 . 
     More specifically, as exemplarily shown in  FIG. 3 , the air hole  122  may be formed in a central region of the body  120  and be elongated in a first direction (the Z-axis) and the light emitting devices  111  may be spaced apart from one another in the longitudinal direction of the air hole  122 . 
     In this case, a majority of the light emitting devices  111  may be arranged proximate to the longitudinal side of the air hole  122 . That is, the light emitting devices  111  may be arranged in two rows in the first direction, the air hole  122  may be elongated in the first direction between the two rows of the light emitting devices  111 , and a majority of the light emitting devices  111  may be arranged proximate to the longitudinal edge of the air hole  122 . This configuration enables effective heat transfer. Of course, the board hole  113  may have a shape corresponding to the shape of the air hole  122 . 
     In addition, when viewed from the upper side, the area of the air hole  122  may be in a range of 10% to 20% of the area of the body  120 . 
     The light emitting device module  100  may further include an air guide  160  protruding in the Y-axis from the other surface of the body  120  along the rim of the air hole  122 . The air guide  160  is in communication with the air hole  122  to form a channel to guide air. 
     The air guide  160  may be cylindrical member having an inner space and the rim of the air guide  160  may overlap the rim of the air hole  122 . That is, the air guide  160  may take the form of a chimney surrounding the air hole  122 . The air guide  160  may have a shape corresponding to the shape of the air hole  122  elongated in the Z direction as shown in  FIG. 3 . 
     The air guide  160  may be formed of a material having high heat transfer efficiency. For example, the air guide  160  may include at least one of aluminum (Al), nickel (Ni), copper (Cu), silver (Ag) and tin (Sn). In addition, the air guide  160  may be formed of at least one of a resin material such as polyphthalamide (PPA), silicon (Si), aluminum (Al), aluminum nitride (AlN), photosensitive glass (PSG), polyamide9T (PA9T), new geo tactics polystyrene (SPS), a metal material, sapphire (Al2O3), beryllium oxide (BeO) and ceramic. 
     The air guide  160  and the radiation fins  130  extend outwardly from the other surface of the body  120  in the same direction such that the air guide  160  extends along the radiation fins  130 . The air guide  160  may be connected to at least some of the radiation fins  130  and receive heat transferred from the light emitting devices  111  to the radiation fins  130 . 
     Accordingly, owing to a temperature difference between the exterior and the interior of the air hole  122  and the air guide  160 , air is guided through the air hole  122  and the air guide  160 . 
     When the light emitting device module  100  is arranged in use, for example as a portion of a streetlight, the light source units  110  direct light downwardly to illuminate the street below. Because the light source units produce heat, although some of the heat is dissipated by the radiation fins  130  oriented above the light source units  110 , a considerable amount of heat is developed directly below the light emitting device module  100 . To facilitate a reduction in this heat below the light emitting device module  100 , the air guide  160  acts as a passive airflow promotion channel together with the generated heat to induce an airflow through the air guide  160  from the bottom side of the light emitting device module  100  to the top side of the light emitting device module  100 . 
     The body  120  may have a connector hole  124  for passage of a connector  190  used to supply power to the light emitting devices  111 . 
     Referring again to  FIGS. 1 and 2 , the module array  200  according to the embodiment, as described above, may be constructed by coupling a plurality of light emitting device modules  100  to one another. 
     Specifically, the module array  200  may be constructed as the plurality of light emitting device modules  100  is arranged in a direction parallel to one surface of the body  120  of each light emitting device module  100  (in the X-Z plane, hereinafter referred to as the horizontal direction). 
     More specifically, the module array  200  may be constructed as the plural light emitting device modules  100  are arranged at a constant pitch. In addition, as exemplarily shown in  FIG. 2 , the module array  200  may be constructed as the plural light emitting device modules  100  are arranged in the transverse direction and/or the longitudinal direction thereof. 
     The module array  200  defines air flow holes  210  between the light emitting device modules  100 . The air flow holes  210  extend from one surface to the other surface of the module array  200  (in the Y-axis, hereinafter referred to as the vertical direction) to provide an air flow space. 
     The air flow holes  210  are located between the light emitting device modules  100  and serve to facilitate the circulation of air by a temperature difference between the interior and the exterior of the air flow holes  210 . 
     The interior of the air flow hole  210  is heated by heat transferred from the light emitting devices  111  through the body  120 . As the heated air is moved upward by buoyancy, a flow of air from the bottom to the top of the air flow hole  210  is created (so-called chimney effect). 
     Accordingly, the air flow holes  210  defined between the light emitting device modules  100  may function to effectively dissipate heat generated by the light emitting device modules  100 . 
     For example, each air flow hole  210  may be defined between the bodies  120  of the two neighboring light emitting device modules  100 . 
     Specifically, the air flow hole  210  may be located between the body  120  of a first light emitting device module  100 - 1  and the body  120  of a second light emitting device module  100 - 2  that is proximate to the first light emitting device module  100 - 1 . 
     More specifically, side surfaces  127  of the bodies  120  of the two neighboring light emitting device modules may define a portion of the inner circumferential surface of the air flow hole  210 . Here, the side surface  127  of the body  120  is a surface that is perpendicular to one surface and the other surface of the body  120  and defines a lateral outer surface of the body  120 . Here, the side surface  127  of the body  120  is a surface that is perpendicular to one surface and the other surface of the body  120  and defines a lateral outer surface of the body  120 . 
     Of course, the air flow hole  210  may be located between the first light emitting device module  100 - 1  and the second light emitting device module  100 - 2  which are next to each other in the transversal direction, and may be located between the first light emitting device module  100 - 1  and a third light emitting device module  100 - 3  which are next to each other in the longitudinal direction. 
     In addition, the side surfaces  127  of the bodies  120  of the two neighboring light emitting device modules may include a portion of an air guide similar to air guide  160 , extending along outer ends of several of the radiation fins  130 , so that two neighboring light emitting device modules together form an air flow hole  210  and an air guide similar to air guide  160 . 
     The module array  200  may further include connection members  220  configured to connect neighboring light emitting device modules  100 . 
     The connection members  220  may interconnect the bodies  120  of the neighboring light emitting device modules  100 . 
     According to the embodiment, two connection members  220  may be spaced apart from each other on a per light emitting device basis. 
     The connection members  220  may be formed of a material having high heat transfer efficiency in consideration of the fact that the connection members  220  define the rim of the air flow hole  210 . 
     The connection members  220  may be formed of a material having high heat transfer efficiency, for example, at least one of aluminum (Al), nickel (Ni), copper (Cu), silver (Ag) and tin (Sn). 
     Specifically, referring to  FIG. 2 , side surfaces  221  of the two connection members  220  spaced apart from each other and the side surfaces  127  of the bodies  120  of the neighboring light emitting device modules  100  may define the inner circumferential surface of the air flow hole  210 . Here, the side surface  221  of the connection member  220  refers to a surface perpendicular to the X-Z plane. 
     For example, the air flow hole  210  may have any one of rectangular, polygonal and circular cross sections. 
     In particular, assuming that the air flow hole  210  has a rectangular cross section, the side surfaces  127  of the bodies  120  of the first light emitting device module  100 - 1  and the second light emitting device module  100 - 2  which are next to each other define facing surfaces of a rectangle, and the side surfaces  221  of the two connection members  220  which interconnect the first light emitting device module  100 - 1  and the second light emitting device module  100 - 2  define the other two facing surfaces of the rectangle. 
     Explaining this again, the light emitting device modules  100  are horizontally spaced apart from each other and connected to each other by the connection members  220 . In this case, the vertically perforated air flow hole  210  is defined by the side surfaces  221  of the connection members  220  and the side surfaces  127  of the bodies  120  of the neighboring light emitting device modules  100 . 
     In addition, the connection members  220  may be positioned respectively at positions of the side surface  127  of the body  120  proximate to corners. As exemplarily shown in  FIG. 2 , positioning the connection members  220  so as to be proximate to the corners of the side surface  127  of the body  120  may increase the size of the air flow hole  210  and may further facilitate circulation of air between the interior and the exterior of the air flow hole  210 . 
     In addition, the connection members  220  may be formed integrally with or separately from the body  120 . 
       FIG. 6  is a view showing the velocity distribution of air in the light emitting device module according to the embodiment. Hereinafter, the flow of air and the radiation of heat in the light emitting device module will be described with reference to  FIG. 6 . 
     The light emitting device module  100  is generally oriented in such a manner that the light emitting devices  111  face downwardly in the direction of gravity, in order to illuminate an object on the ground. 
     When power is applied to the light emitting devices  111 , the light emitting devices  111  generate light and also generate heat. The heat generated from the light emitting devices  111  is transferred to the board  112  and the heat radiation pad  150  and then diffused to the body  120 , the air guide  160  and the radiation fins  130 . 
     In particular, most of the heat generated from the light emitting devices  111  will be transferred to the body  120 , the radiation fins  130  and the air guide  160 , all of which are formed of materials having high heat transfer efficiency. 
     Accordingly, a temperature difference occurs between the exterior and the interior of the light emitting device module  100 . In particular, the interior of the air hole  122  and the air guide  160  has a higher temperature than that of the exterior of the light emitting device module  100 . 
     Accordingly, the interior air of the air hole  122  and the air guide  160  is moved upward by buoyancy, and cold air is introduced upward from the exterior below the light emitting devices  111 , to create a chimney effect. 
     This circulation of air may maximize heat radiation of the light emitting devices  111  using the outside air. 
     In particular, as exemplarily shown in  FIG. 6 , the velocity of air having passed through the air guide  160  and the air hole  122  is higher than that of air in other regions. Accordingly, the embodiment may achieve fan-like cooling without using a fan. 
     In addition, the provision of the air flow hole  210  between the neighboring light emitting device modules  100  may cause a chimney effect due to a temperature difference between the interior and the exterior of the air flow hole  210 , thereby facilitating circulation of air. 
     The circulation of air facilitated by this chimney effect may result in more effective cooling of the light emitting device module  100 . 
       FIG. 7  is a lower side view of a module array according to another embodiment of the present invention. 
     The module array according to the present embodiment, designated by reference numeral  200 A, differs from that of the embodiment shown in  FIG. 2  in terms of the configuration of the connection member  220 . 
     The connection member  220  according to the embodiment may include a slide groove  220 A formed in the body  120  of any one light emitting device module (for example, the first light emitting device module  100 - 1 ) and a slide protrusion  220 B formed at the body  120  of the other light emitting device module (for example, the second light emitting device module  100 - 2 ) proximate to the first light emitting device module  100 - 1 , the slide protrusion  220 B being configured to slide and be fitted into the slide groove  220 A. 
     The slide groove  220 A provides a space into which the slide protrusion  220 B is fitted and secured. The slide groove  220 A may have a shape corresponding to the shape of the slide protrusion  220 B to allow the slide protrusion  220 B to slide and be fitted therein. Specifically, the slide groove  220 A may be tapered such that the width thereof is reduced outward, like part of a dovetail joint. 
     The slide groove  220 A may be formed in the body  120  of any one light emitting device module  100 - 1 . The slide groove  220 A may be formed integrally with or separately from the body  120 . The slide groove  200 A may be horizontally indented in the side surface  127  of the body  120 . 
     The slide protrusion  220 B is fitted into the slide groove  220 A via sliding thereof. The slide protrusion  220 B may have a shape corresponding to the shape of the slide groove  220 A so as to slide and be fitted into the slide groove  220 A. In particular, for convenience of assembly, the slide protrusion  220 B may be vertically inserted into the slide groove  220 A. 
     Specifically, the slide protrusion  220 B may be tapered such that the width thereof is increased outward, like part of a dovetail joint. 
     The slide protrusion  220 B may be formed at the body  120  of any one light emitting device module  100 - 2 . The slide protrusion  220 B may be formed integrally with or separately from the body  120 . Specifically, the slide protrusion  220 B may horizontally protrude from the side surface  127  of the body  120 . 
     To enhance coupling force between the light emitting device modules  100 , the slide protrusion  220 B may be interference-fitted into the slide groove  220 A. 
     Through use of the slide protrusion  220 B and the slide groove  220 A, the neighboring light emitting device modules  100  may be conveniently assembled with each other while defining the air flow hole  210  therebetween. 
     In addition, the number of the light emitting device modules  100  included in the module array  200  may be easily adjusted in consideration of the lighting capacity and the spatial volume of the lighting apparatus. 
       FIG. 8  is an exploded perspective view of a light emitting device module according to a second embodiment. Referring to  FIG. 8 , the light emitting device module  100 A may include a body  120  provided at one surface thereof with a plurality of seats  121 A, and a plurality of radiation fins  130  arranged at the other surface of the body  120  opposite to the one surface of the body  120  provided with the seats  121 A. 
     In addition, the light emitting device module  100 A may include an air hole  122  perforated in the body  120  from the seats  121 A to the radiation fins  130  for the flow of air. 
     A plurality of boards  112 A are provided, and light emitting devices  111  are disposed on the boards  112 A, the light emitting devices  111  being electrically connected to the boards  112 A. 
     The boards  112 A are disposed on one surface of the body  120 . The boards  112 A have the form of a square, without being limited thereto. For example, the boards  112 A may have one of various shapes, such as a polygonal shape, an oval shape, etc. The boards  112 A may include a circuit pattern printed on an insulator. For example, the boards  112 A may be general Printed Circuit Boards (PCB), a metal core PCB, a flexible PCB, a ceramic PCB or the like. 
     An upper surface of the boards  112 A may be coated with a material capable of efficiently reflecting light. For example, the upper surface of the boards  112 A may be coated with a white or silvery material. 
     A single light emitting device or a plurality of light emitting devices  111  may be arranged. In addition, in the case of arrangement of the plurality of light emitting devices  111 , the respective light emitting devices  111  may emit different colors of light, or may exhibit different color temperatures. 
     The boards  112 A may be disposed on the seats  121 A formed at one surface of the body  120  and be supported by the body  120 . The seats  121 A may be indented in one surface of the body  120 , and the boards  112 A may have a shape corresponding to the shape of the seats  121 A so as to be inserted into the seats  121 A. 
     In this embodiment, the board hole  113  of the first embodiment is not provided, since the air hole  122  is not obstructed by the boards  112 A. 
     The light emitting devices  111  on the boards  112 A may be arranged to surround the air hole  122 . More specifically, the light emitting devices  111  may be arranged around the air hole  122  in the X-Z plane. 
     A plurality of heat radiation pads  150 A may be additionally provided between the boards  112 A and the seats  121 A for enhancement of heat transfer. The heat radiation pads  150 A may have a shape corresponding to the seats  121 A and may be formed of a material having excellent heat transfer and adhesion properties. For example, the heat radiation pads  150 A may be formed of silicon. 
     The light emitting device module  100 A may further include a plurality of lenses  141  which shield the light emitting devices  111  and refract light emitted from the light emitting devices  111 . The lenses  141  function to diffuse light emitted from the light emitting devices  111 . A diffusion angle of light emitted from the light emitting devices  111  may be determined based on the shape of the lenses  141 . For example, the lenses  141  may allow the light emitting devices  111  to be molded in a convex form. 
     The lenses  141  may be formed of a light transmitting material. For example, the lenses  141  may be formed of transparent silicon, epoxy and one or more various other resins. 
     In addition, each lens  141  may be positioned to enclose the light emitting device  111  to isolate the light emitting device  111  from the outside, in order to protect the light emitting device  111  from external moisture and shock. 
     This configuration of the boards  112 A, seats  121 A, pads  150 A and lenses  141  as discrete elements eliminates the need for the board hole  113 , the pad hole  153  and the cover hole  143  of the first embodiment, while still permitting heat of the light emitting devices  111  to enter the air hole  122 . 
     Screw holes  126  may be formed in corners of the body  120  such that screws are fastened through the screw holes  126  for coupling the body  120  to a lighting apparatus, for example. 
     In addition, the body  120  may have a connector hole  124  for passage of a connector  190  used to supply power to the light emitting devices  111 . 
       FIG. 9  is an exploded perspective view of a light emitting device module according to a third embodiment. Referring to  FIG. 9 , the light emitting device module  100 B may include a plurality of light source units  110 B, a body  120  provided at one surface thereof with a plurality of seats  121 B on which the light source units  110 B are seated, and a plurality of radiation fins  130  arranged at the other surface of the body  120  opposite to the one surface of the body  120  provided with the seats  121 B. In this embodiment, two light source units  110 B are provided spaced apart from one another, and generally parallel with one another, although not limited thereto. 
     In addition, the light emitting device module  100 B may include an air hole  122  perforated in the body  120  from the seats  121 B to the radiation fins  130  for the flow of air. 
     The light source units  110 B include a board  112 , and light emitting devices  111  disposed on the board  112 , the light emitting devices  111  being electrically connected to the board  112 . In this embodiment, two light source units  110 B are provided spaced apart from one another, such that two boards  112  are provided. 
     The boards  112  are disposed on one surface of the body  120 . The boards  112  have the form of an elongate rectangular strip, without being limited thereto. The boards  112  may include a circuit pattern printed on an insulator. For example, each board  112  may be a general Printed Circuit Board (PCB), a metal core PCB, a flexible PCB, a ceramic PCB or the like. 
     An upper surface of the boards  112  may be coated with a material capable of efficiently reflecting light. For example, the upper surface of the boards  112  may be coated with a white or silvery material. 
     A single light emitting device or a plurality of light emitting devices  111  may be arranged. In addition, in the case of arrangement of the plurality of light emitting devices  111 , the respective light emitting devices  111  may emit different colors of light, or may exhibit different color temperatures. 
     The boards  112  may be disposed on the seats  121 B formed at one surface of the body  120  and be supported by the body  120 . The seats  121 B may be indented in one surface of the body  120 , and the boards  112  may have a shape corresponding to the shape of the seats  121 B so as to be inserted into the seats  121 B. 
     In this embodiment, the board hole  113  of the first embodiment is not provided, since the air hole  122  is not obstructed by the boards  112 . 
     The light emitting devices  111  on the boards  112  may be arranged to surround the air hole  122 . More specifically, the light emitting devices  111  may be arranged around the air hole  122  in the X-Z plane. 
     A plurality of heat radiation pads  150 B may be additionally provided between the boards  112  and the seats  121 B for enhancement of heat transfer. The heat radiation pads  150 B may have a shape corresponding to the seats  121 B and may be formed of a material having excellent heat transfer and adhesion properties. For example, the heat radiation pads  150 B may be formed of silicon. 
     The light emitting device module  100 B may further include a plurality of lenses  141  which shield the light emitting devices  111  and refract light emitted from the light emitting devices  111 . The lenses  141  function to diffuse light emitted from the light emitting devices  111 . A diffusion angle of light emitted from the light emitting devices  111  may be determined based on the shape of the lenses  141 . For example, the lenses  141  may allow the light emitting devices  111  to be molded in a convex form. 
     The lenses  141  may be formed of a light transmitting material. For example, the lenses  141  may be formed of transparent silicon, epoxy and one or more various other resins. 
     In addition, each lens  141  may be positioned to enclose the light emitting device  111  to isolate the light emitting device  111  from the outside, in order to protect the light emitting device  111  from external moisture and shock. 
     For convenience of assembly, the lenses  141  may be disposed on a lens cover  142  having a shape corresponding to the shape of the boards  112 . The lens cover  142  may be formed to correspond to the boards  112 , and the lenses  141  on the lens cover  142  may be positioned to overlap the respective light emitting devices  111 . 
     This configuration of the boards  112 , seats  121 B, pads  150 B and lens covers  142  as separate spaced-apart units eliminates the need for the board hole  113 , the pad hole  153  and the cover hole  143  of the first embodiment, while still permitting heat of the light emitting devices  111  to enter the air hole  122 . 
     Screw holes  126  may be formed in corners of the body  120  such that screws are fastened through the screw holes  126  for coupling the body  120  to a lighting apparatus, for example. 
     In addition, the body  120  may have a connector hole  124  for passage of a connector  190  used to supply power to the light emitting devices  111 . 
       FIG. 10  is a perspective view of a lighting apparatus including the light emitting device modules  100  according to the present invention. Referring to  FIG. 10 , the lighting apparatus of the embodiment, designated by reference numeral  1000 , may include a main body  1100  that provides a space for installation of the light emitting device modules  100  and defines an external appearance of the lighting apparatus  1000 , and a connector  1200  that is coupled to one side of the main body  1100  and connects the main body  1100  to a support member (not shown), a power source unit (not shown) to supply power to the main body  1100  being mounted in the connector  1200 . 
     The lighting apparatus  1000  of the embodiment may be installed indoors or outdoors. For example, the lighting apparatus  1000  of the embodiment may be applied to a streetlamp. 
     The main body  1100  may be organized by a plurality of frames  1110  to provide a space for installation of at least three light emitting device modules  100 . 
     The connector  1200  incorporates the power source unit (not shown) therein and connects the main body  1100  to the support member (not shown). The support member serves to fix the main body  1100  to an external structure. 
     Through use of the lighting apparatus  1000  of the embodiment, heat generated by the light emitting device modules  100  may be effectively dissipated by a chimney effect without using a fan, which results in reduced manufacturing costs. 
     As is apparent from the above description, according to the embodiment, the interior of an air hole and an air guide has a higher temperature than that of the exterior of a light emitting device module, which causes air inside the air hole and the air guide to be moved upward by buoyancy and cold air to be introduced from the exterior below light emitting devices (chimney effect). In this way, heat generated by the light emitting device module may be effectively dissipated. 
     In addition, according to the embodiment, the velocity of air having passed through the air hole and the air guide is faster than that in general convection caused by heat, resulting in enhanced heat radiation efficiency. 
     In addition, according to the embodiment, effective cooling may be accomplished without using a fan. 
     When using a lighting apparatus according to the embodiment, heat generated by the light emitting device module may be effectively dissipated by a chimney effect without using a fan, which may cause a reduction of manufacturing costs. 
     In addition, according to the embodiment, an air flow hole is defined between neighboring light emitting device modules to facilitate circulation of air based on a chimney effect due to a temperature difference between the interior and the exterior of the air flow hole. 
     In addition, according to the embodiment, through provision of a slide protrusion and a slide groove, the neighboring light emitting device modules may be more conveniently assembled while defining the air flow hole therebetween. 
     In addition, according to the embodiment, the number of light emitting device modules included in a module array may be easily adjusted in consideration of the lighting capacity and the spatial volume of the lighting apparatus. 
     Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. For example, the respective components specifically defined in the embodiments may be modified. In addition, differences associated with these modifications and applications should be interpreted to be embraced in the scope of the present invention as defined in the accompanying claims.