Patent Publication Number: US-9835306-B2

Title: LED illumination apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/463,028, filed on Aug. 19, 2014, which is a continuation of U.S. patent application Ser. No. 13/305,157, filed on Nov. 28, 2011, and now issued as U.S. Pat. No. 8,840,269, and claims priority from and the benefit of Korean Patent Application No. 10-2010-0118952, filed on Nov. 26, 2010, Korean Patent Application No. 10-2011-0020948, filed on Mar. 9, 2011, Korean Patent Application No. 10-2011-0021965, filed on Mar. 11, 2011, Korean Patent Application No. 10-2011-0049504, filed on May 25, 2011, and Korean Patent Application No. 10-2011-0090835, filed on Sep. 7, 2011, which are all incorporated herein by reference for all purposes as if fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     Exemplary embodiments of the present invention relate to a light emitting diode (LED) illumination apparatus, and more particularly, to an LED illumination apparatus which may realize wide light distribution by increasing the angular range of radiation and achieve uniform intensity of light and a variety of light distribution patterns to reduce the loss of light that is generated by a light source and is radiated to the outside. 
     Discussion of the Background 
     Incandescent lamps and fluorescent lamps are widely used for indoor or outdoor lighting. The incandescent lamps or fluorescent lamps have a problem in that they should be frequently replaced due to their short lifespan. 
     In order to solve this problem, an illumination apparatus using LEDs has been developed. LEDs, when applied to illumination apparatus, have excellent characteristics, such as good controllability, rapid response, high electricity-to-light conversion efficiency, long lifetime, low power consumption, and high luminance. 
     In particular, the LED has an advantage in that it consumes little power due to high electricity-to-light conversion efficiency. In addition, the LED has a rapid on-off because since no preheating time is necessary, attributable to the fact that its light emission is neither thermal light emission nor discharge light emission. 
     Furthermore, the LED has advantages in that it is resistant to and safe from impact since neither gas nor a filament is disposed therein, in that it consumes little electrical power, operates at high repetition and high pulses, decreases optic nerve fatigue, has a lifespan so long that it can be considered semi-permanent, and realizes illumination in various colors due to the use of a stable direct lighting mode, and in that it can be miniaturized since a small light source is used. 
       FIG. 1  is a perspective view that illustrates a typical LED illumination apparatus. In the LED illumination apparatus, a plurality of LED devices  11  is disposed on a substrate  12 , which is disposed on a heat sink  13  such that the heat that is generated when the LED devices  11  emit light can be dissipated to the outside. Heat dissipation fins  14  protrude from the outer surface of the heat sink  13  so as to increase the area of heat dissipation. A socket  15  is connected to an external power source, and a transparent cover  16  protects the LED devices  11  from the external environment. 
     However, since the LED device  11  defines an angular range of radiation from 120° to 130° when emitting light, an LED illumination apparatus, which is realized using the LED devices  11 , exhibits a light distribution, as illustrated in  FIG. 9B , which is focused substantially in the forward direction but not in the backward direction. 
     Accordingly, the light distribution characteristic of the LED illumination apparatus is not as good as that of an incandescent lamp, that is, light distribution in which light is directed backward, as illustrated in  FIG. 9A . This causes a problem in that a sufficient intensity of illumination is not guaranteed in indoor or outdoor spaces. 
     SUMMARY OF THE INVENTION 
     Exemplary embodiments of the present invention provide a Light Emitting Diode (LED) illumination apparatus. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that can achieve a wide light distribution with an increased angular range of radiation by directing a portion of the light that is generated by the light source to the side and rear of the illumination apparatus. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that has an increased angular range of radiation and achieves uniform intensity of light by positioning a reflector, which directs a portion of the light that is generated from a light source to the side and rear of the illumination apparatus, above and spaced apart from the light source. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that can achieve uniform intensity of light by arranging a plurality of light sources in peripheral and inner areas of a substrate such that the light sources do not overlap each other. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that achieves uniform intensity of light by designing a reflector, which reflects light that is generated from a plurality of light sources, in a multistage structure such that the light sources are arranged at different heights. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that achieves a variety of light distribution patterns by radiating light that is generated by a first light source and light that is generated by a second light source to the outside through respective first and second covers, which are partitioned by a reflector and have different transmittances. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that can be easily implemented since a fluorescent material, which converts light that is generated by an LED into white light, is contained in a cover. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that achieves a variety of illumination patterns according to the mood by separating light that is generated by a first light source and light that is generated by a second light source from each other using a reflector, the first and second light sources being designed to generate different types of light. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that guides light that is generated by a light source to the rear and reduces the interference of the light using a cover, which is provided above a heat sink on which a substrate is mounted, thereby reducing the loss of the light that is radiated to the rear is reduced. 
     Exemplary embodiments of the present invention also provide an LED illumination apparatus that decreases the distance between a light source and a cover, which surrounds the light source, by forming the cover to be aspheric, so that the loss of the light that is radiated to the front is reduced, thereby increasing the entire light efficiency. 
     An exemplary embodiment of the present invention provides an LED illumination apparatus that includes a substrate, a first light source disposed on a peripheral area of the substrate, a second light source disposed on an inner area of the substrate, and a reflector disposed between the first light source and the second light source, wherein the reflector is configured to reflect light that is generated by the first light source. 
     Another exemplary embodiment of the present invention also provides an LED illumination apparatus that includes a substrate, a plurality of first light emitting devices disposed on a peripheral area of the substrate, a reflector disposed on an inner area of the substrate, wherein the reflector has a first height to reflect light that is generated by the first light emitting devices, and a plurality of second light emitting devices disposed on an upper surface of the reflector such that the second light emitting devices are disposed at a second height different from the first light emitting devices. The second light emitting devices are electrically connected to the substrate. The second light emitting devices are alternately disposed with the first light emitting devices that are disposed adjacent to the second light emitting devices. 
     Another exemplary embodiment of the present invention also provides an LED illumination apparatus that includes a substrate, a light source comprising a first light source disposed on a peripheral area of the substrate and a second light source disposed on an inner area of the substrate, a reflector disposed on a boundary area between the first light source and the second light source and having a first height, wherein the reflector is configured to divide light that is generated by the first light source from light that is generated by the second light source, and a cover comprising a first cover unit to allow the light that is generated by the first light source to pass to an outside and a second cover unit to allow the light that is generated by the second light source to pass to an outside. The first and second cover units have different light transmittances. 
     Another exemplary embodiment of the present invention also discloses an LED illumination apparatus that includes a substrate, a light source, wherein the light source comprises a first light source and a second light source, which are disposed on the substrate, a reflector to reflect light that is generated by the first light source and the second light source, wherein the reflector is configured to partition an area of the first light source from an area of the second light source, a cover to allow the light that is generated by the light source to pass through, a heat sink disposed under the substrate, and an inclined guide surface formed on the heat sink. A slope of the guide surface increases from an edge of an upper surface toward a lower portion of the heat sink. The guide surface has a maximum outer diameter that is equal to or smaller than that of the cover. 
     According to embodiments of the invention, the reflector is disposed in the boundary area between the first light source, which is disposed on the substrate, and the second light source, which is disposed on the substrate in an area that is more inward than that of the first light source, to reflect light that is generated by the first light source toward the side and rear, thereby increasing the angular range of radiation. Consequently, the distribution of light that is generated by the first light source can be made similar to that of an incandescent lamp. Accordingly, the LED illumination apparatus can replace the incandescent lamp in lighting devices that use incandescent lamps without decreasing illumination efficiency. In addition, since a wide angular range can be achieved, the LED illumination apparatus can be used for main illumination rather than localized illumination, thereby increasing the range of use and applicability. 
     In addition, it is possible to increase the angular range and achieve uniform intensity of light by positioning a reflector, which directs a portion of the light that is generated by the light source toward the side and rear of the illumination apparatus, above and spaced apart from the light source, which is disposed on a substrate. 
     Furthermore, it is possible to achieve uniform intensity of light by arranging a plurality of light sources, which are disposed on the peripheral and inner areas of a substrate, such that they do not overlap each other. 
     In addition, it is possible to achieve uniform intensity of light by arranging a plurality of light sources, which are disposed on the peripheral and inner areas of the substrate, such that they do not overlap each other and are positioned at different heights. 
     In addition, it is possible to achieve a variety of light distribution patterns by radiating light that is generated by the first light source and light that is generated by the second light source to the outside through the respective first and second covers, which are partitioned by the reflector and have different transmittances. 
     Furthermore, it is possible to easily fabricate the LED illumination apparatus and improve productivity, since the fluorescent material, which converts light that is generated by the LED into white light, is contained in the cover. 
     In addition, it is possible to achieve a variety of illumination patterns according to the mood by separating light that is generated by the first light source and light that is generated by the second light source from each other using the reflector, the first and second light sources being designed to generate different types of light. 
     Furthermore, it is possible to guide light that is generated by the light source to the rear and reduce the interference of the light using the cover, which is provided above the heat sink on which the substrate is mounted, so that the loss of the light that is radiated to the rear is reduced, thereby increasing the entire light efficiency. 
     Moreover, it is possible to decrease the distance between the light source and the cover, which surrounds the light source, by forming the cover to be aspheric, so that the loss of the light that is radiated to the front is reduced, thereby increasing the entire light efficiency. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view that illustrates a typical LED illumination apparatus. 
         FIG. 2  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a first exemplary embodiment of the invention. 
         FIG. 3  is a perspective view that illustrates the LED illumination apparatus according to the first exemplary embodiment of the invention. 
         FIG. 4  is a top plan view that illustrates the layout of the light sources illustrated in  FIG. 3 . 
         FIG. 5  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in case the reflector employed in the present invention is disposed on the upper surface of the substrate. 
         FIG. 6A ,  FIG. 6B ,  FIG. 6C , and  FIG. 6D  are cross-sectional views that illustrate several structures of the reflector employed in the present invention, in which  FIG. 6A  is a single curved structure,  FIG. 6B  is a combination of a straight vertical section and an inclined section,  FIG. 6C  is a combination of a curved section and an inclined section, and  FIG. 6D  is a combination of a straight vertical section and a curved section. 
         FIG. 7A ,  FIG. 7B , and  FIG. 7C  are cross-sectional views that illustrate several coupling states between the reflector and the substrate, which are employed in the present invention, in which  FIG. 7A  is a fitting type using a fitting protrusion,  FIG. 7B  is a faster type using a fastening member, and  FIG. 7C  is a bonding type using an adhesive. 
         FIG. 8A ,  FIG. 8B , and  FIG. 8C  are top plan views that illustrate several structures of the reflector employed in the present invention, in which  FIG. 8A  shows a reflector having a cavity,  FIG. 8B  shows a reflector having a wavy cross section, and  FIG. 8C  shows a reflector having a toothed cross section. 
         FIG. 9A ,  FIG. 9B , and  FIG. 9C  are graphs showing the distribution of light that is generated from a light source, in which an incandescent lamp was used in  FIG. 9A , a typical LED illumination apparatus was used in  FIG. 9A , and an LED illumination apparatus of the present invention was used in  FIG. 9A . 
         FIG. 10  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a second exemplary embodiment of the invention. 
         FIG. 11  is a perspective view of the LED illumination apparatus illustrated in  FIG. 10 . 
         FIG. 12  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a third exemplary embodiment of the invention. 
         FIG. 13  is a perspective view of the LED illumination apparatus illustrated in  FIG. 12 . 
         FIG. 14  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a fourth exemplary embodiment of the invention. 
         FIG. 15  is a perspective view of the LED illumination apparatus illustrated in  FIG. 14 . 
         FIG. 16  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a fifth exemplary embodiment of the invention. 
         FIG. 17  is a perspective view of the LED illumination apparatus illustrated in  FIG. 16 . 
         FIG. 18  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a sixth exemplary embodiment of the invention. 
         FIG. 19  is a perspective view of the LED illumination apparatus illustrated in  FIG. 18 . 
         FIG. 20  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in the LED illumination apparatus illustrated in  FIG. 18 . 
         FIG. 21  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a seventh exemplary embodiment of the invention. 
         FIG. 22  is a perspective view of the LED illumination apparatus illustrated in  FIG. 21 . 
         FIG. 23  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in the LED illumination apparatus illustrated in  FIG. 21 . 
         FIG. 24  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to an eighth exemplary embodiment of the invention. 
         FIG. 25  is a perspective view of the LED illumination apparatus illustrated in  FIG. 24 . 
         FIG. 26  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in the LED illumination apparatus illustrated in  FIG. 24 . 
         FIG. 27  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a ninth exemplary embodiment of the invention. 
         FIG. 28  is a perspective view of the LED illumination apparatus illustrated in  FIG. 27 . 
         FIG. 29  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in the LED illumination apparatus illustrated in  FIG. 27 . 
         FIG. 30  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to a tenth exemplary embodiment of the invention. 
         FIG. 31  is a perspective view that illustrates the LED illumination apparatus according to the tenth exemplary embodiment of the invention. 
         FIG. 32  is a top plan view that illustrates the arrangement of light sources in the LED illumination apparatus according to the tenth exemplary embodiment of the invention. 
         FIG. 33  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in case the reflector is disposed on the top surface of the substrate in the LED illumination apparatus illustrated in  FIG. 30 . 
         FIG. 34A ,  FIG. 34B ,  FIG. 34C ,  FIG. 34D , and  FIG. 34E  are cross-sectional views that illustrate several structures of the reflector employed in the tenth exemplary embodiment of the present invention, in which  FIG. 34A  is a single straight structure,  FIG. 34B  is a single curved structure,  FIG. 34C  is a combination of a straight vertical section and an inclined section,  FIG. 34D  is a combination of a curved section and an inclined section, and  FIG. 34E  is a combination of a straight vertical section and a curved section. 
         FIG. 35A ,  FIG. 35B , and  FIG. 35C  are cross-sectional views that illustrate several structures in which the reflector is coupled to the substrate in the LED illumination apparatus illustrated in  FIG. 30 , in which  FIG. 35A  shows a fitting type using a hook,  FIG. 35B  shows a fastening type using a fastening member, and  FIG. 35C  shows a bonding type using an adhesive. 
         FIG. 36A ,  FIG. 36B , and  FIG. 36C  are top plan views that illustrate several structures of the second surface of the reflector in the LED illumination apparatus illustrated in  FIG. 30 , in which  FIG. 36A  shows a reflector having a circular cross section,  FIG. 36B  shows a reflector having a wavy cross section, and  FIG. 36C  shows a reflector having a toothed cross section. 
         FIG. 37  is a cross-sectional view that illustrates the overall configuration of an LED illumination apparatus according to another embodiment of the present invention. 
         FIG. 38  is a perspective view of the LED illumination apparatus illustrated in  FIG. 37 . 
         FIG. 39  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in the LED illumination apparatus illustrated in  FIG. 37 . 
         FIG. 40  is a configuration view of the LED illumination apparatus illustrated in  FIG. 37 , which contains the fluorescent material in the cover. 
         FIG. 41  is a view that illustrates a variation of the LED illumination apparatus illustrated in  FIG. 37 . 
         FIG. 42  is a configuration view that illustrates an LED illumination apparatus according to another embodiment of the present invention, in which a first light source and a second light source are implemented as LEDs having different colors. 
         FIG. 43A ,  FIG. 43B , and  FIG. 43C  are graphs showing light distribution depending on the transmittances of the first and second covers in the LED illumination apparatus according to another embodiment of the present invention, in which  FIG. 43A  shows the case in which the first and second covers have the same transmittance,  FIG. 43B  shows the case in which the transmittance of the first cover is higher than that of the second cover, and  FIG. 43C  shows the case in which the transmittance of the second cover is lower than that of the first cover. 
         FIG. 44  is a cross-sectional view that illustrates an overall LED illumination apparatus according to another embodiment of the present invention. 
         FIG. 45  is a perspective view of the LED illumination apparatus illustrated in  FIG. 44 . 
         FIG. 46  is a detailed view that illustrates the reflection of light by the reflector and the travel of light in the LED illumination apparatus illustrated in  FIG. 44 . 
         FIG. 47  is a configuration view of the LED illumination apparatus illustrated in  FIG. 44 , which contains the fluorescent material in the cover. 
         FIG. 48  is a view that illustrates a variation of the LED illumination apparatus illustrated in  FIG. 46 . 
         FIG. 49  is a view that illustrates another coupling relationship between the cover and the heat sink in the LED illumination apparatus illustrated in  FIG. 46 . 
         FIG. 50  is an overall configuration view of the LED illumination apparatus illustrated in  FIG. 46 , which has the cover coupled to the mounting surface of the heat sink. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS 
     The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals in the drawings denote like elements. 
     It will be understood that when an element or layer is referred to as being “on” or “connected to” another element or layer, it can be directly on or directly connected to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on” or “directly connected to” another element or layer, there are no intervening elements or layers present. In contrast, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being “beneath” another element, it can be directly beneath the other element or intervening elements may also be present. Meanwhile, when an element is referred to as being “directly beneath” another element, there are no intervening elements present. 
     Throughout this document, reference should be made to the drawings, in which the same reference numerals and signs are used throughout the different drawings to designate the same or similar components. 
     As illustrated in  FIG. 2  to  FIG. 50 , light emitting diode (LED) illumination apparatuses  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 ,  900 ,  1000 ,  1100 , and  1200  according to exemplary embodiments of the invention may include a substrate  110 , a first light source  111 , a second light source  112 , and a reflector  130 ,  230 , or  1030 . 
     The substrate  110  may be a circuit board member, which has a certain circuit pattern disposed on an upper surface thereof, such that the circuit pattern is electrically connected to an external power, which is supplied through a power cable (not shown), and is electrically connected to the light sources  111  and  112 . 
     The substrate  110  may be disposed on an upper surface of a heat sink  120 , with a heat dissipation pad  121  interposed between the substrate  110  and the heat sink  120 . The heat sink  120  may be made of a metal, such as aluminum (Al), having excellent heat conductivity, such that it can dissipate the heat that is generated when the light sources emit light to the outside. 
     The heat sink  120  may have a plurality of heat dissipation fins on the outer surface thereof to increase heat dissipation efficiency by increasing the heat dissipation area. The heat sink  120  may have a guide surface  124  on the upper portion thereof, the guide surface  124  being cut open from the inside to the outside. The guide surface  124  includes an inner portion  124 A having a first slope, an outer portion  124 B having a second slope that is greater than the first slope, and a middle portion  124 C disposed between the first portion  124 A and the second portion  124 B. The guide surface  124  serves to increase the area through which the light travels in the backward direction, thereby increasing the angular range of radiation of the light while a portion of the light that is generated by the light sources is reflected to the side and rear by the reflector  130 ,  230 , or  1030 . The reflector  130 ,  230 , or  1030  will be described later. 
     Although the substrate  110  has been illustrated and described as having the form of a disc conforming to the shape of a mounting area  122 , i.e. the upper surface of the heat sink  120 , other shape is also possible. For example, the substrate  110  may be formed as a polygonal plate, such as a triangular or rectangular plate. 
     In addition, although the substrate  110  has been illustrated and described as being bonded to the upper surface of the heat sink  120  via the heat dissipation pad  121 , other configuration is also possible. It should be understood that the substrate  110  may be detachably assembled to the mounting area  122  of the heat sink  120  via a fastening member. 
     In addition, a light-transmitting cover  140  having a space S therein is disposed on the middle portion  124 B of the guide surface  124  and covers the mounting area  122  of the heat sink  120 . The light-transmitting cover  140  radiates the light that is emitted from the light sources to the outside while protecting the light sources. The light-transmitting cover  140  may be formed as a light spreading cover in order to radiate the light that is generated by the light sources to the outside by spreading. 
     Although the light-transmitting cover  140  has been illustrated and described as being hemispherical, other configuration is also possible. For example, the light-transmitting cover  140  may have an extension  231  as shown in  FIG. 26 , which extends from an intermediate portion in the height direction to the lower portion of the hemisphere, to increase the reflection area, in which light is reflected to the side and rear by the reflector  130 ,  230 , or  1030 , in the backward direction. The extension  231  may be bent inward at a certain angle such that it is positioned lower than the height at which the first light source  111  is disposed on the substrate  110 , thereby increasing the area illuminated by the light emitted from the first light source  111 . 
     The reflector  130  or  230  may be disposed on the upper portion of the substrate  110 , as illustrated in  FIG. 2  to  FIG. 50 , and serve to reflect the light that is generated by the first light source  111  to the side and rear. 
     The reflector  130  or  230  may be formed as a reflector plate having a certain height, and may be disposed on the boundary area between the one or more first light sources  111 , which are disposed on the peripheral area of the substrate  110 , and the one or more second light sources  112 , which are disposed on the inner area of the substrate  110 . The reflector  130  or  230  has a cross-sectional shape that can reflect the light that is generated by the first light source  111 , which is arranged on the peripheral area, to the side and rear of the substrate  110 . 
     Here, the first light source  111  and the second light source  112  may be formed as a chip-on-board (COB) assembly, in which a plurality of LED chips are integrated on a board  114 , as illustrated in  FIG. 10 , an LED package including lead frames, or a combination thereof. 
     As illustrated in  FIG. 2  and  FIG. 3 , the first light source  111 , which may include a plurality of LED devices, is arrayed in a certain pattern on the peripheral area of the substrate  110 , and the second light source  112 , which may include a plurality of LED devices, is arrayed in another certain pattern on the inner area of the substrate  110 . 
     In case the first light source  111  may include a plurality of first LED devices and the second light source  112  may include a plurality of second LED devices, the second LED devices  112  may be positioned such that they are alternately disposed with the first LED devices  111 , which are disposed on the peripheral area of the substrate  110 , as illustrated in  FIG. 4 . This is intended to make the light beams generated by the first LED devices  111  and the light beams generated by the second LED devices  112  to share the entire area of the light-transmitting cover  140 , so that overall intensity of light is uniform. 
     In addition, as illustrated in  FIG. 10  and  FIG. 11 , the second light source  112  in the inner area may be provided as a COB assembly, in which the LED chips are integrated. The first light source  111  in the peripheral area may include the packaged LED devices. 
     As illustrated in  FIG. 12  to  FIG. 15 , both the first light source  111  at the peripheral area of the substrate  110  and the second light source  112  at the inner area may be provided as a COB assembly. 
     Here, if both the first light sources  111  and the second light sources  112  are formed as a COB assembly, the first light sources  111  and the second light sources  112  may be disposed on a board  114 , such that the first light source  111 , the second light source  112 , and the reflector  130  may form a single device. In this case, the lower end of the reflector  130  is fixed to the upper surface of the board  114 . 
     In addition, as illustrated in  FIG. 14  and  FIG. 15 , the board on which the LED chips  112  are disposed may be divided into two sections, including a first board  114   a , which is disposed on the peripheral area of the substrate  110 , and a second board  114   b , which is disposed in the inner area of the substrate  110 . The LED chips  111  that act as the first light source may be integrally disposed on the first board  114   a , and the LED chips  112  that act as the second light source may be integrally disposed on the second board  114   b . In this case, the reflector  130  is disposed at the boundary between the first board  114   a  and the second board  114   b , and the lower end of the reflector  130  is fixed to the substrate  110 , which is disposed under the first and second boards  123   a  and  123   b.    
     In case the lower end of the reflector is fixed to the substrate  110  or the board  114  as illustrated in  FIG. 14  to  FIG. 15 , a portion of light L 1  that is generated by the first light source  111 , which is disposed on the peripheral area of the substrate  110  or the board  114 , is reflected by the outer surface of the reflector  130  so that it is radiated to the side and rear of the substrate  110  as illustrated in  FIG. 5 . At the same time, the remaining portion of the light L 1  is not reflected by the reflector  130 ,  230  but is directly radiated toward the light-transmitting cover  140 . 
     In addition, light L 2  that is generated by the second light source  112 , which is disposed on the inner area of the substrate  110 , is radiated toward the light-transmitting cover  140 , either after being reflected by the inner surface of the reflector  130  or without being reflected by the reflector  130 ,  230 . 
     Here, the shape of the heat sink  120  should be designed to reduce interference of the portion of the light L 1  that is generated by the first light source  111 . Otherwise, the portion of the light L 1  encounters interference by colliding with the heat sink  120  while traveling backward after being reflected by the outer surface of the reflector  130  or  230 . For this, as described above, the guide surface  124 , which has a downward slope at a certain angle, may be attached on the outer circumference of the heat sink  120  on which the substrate  110  is disposed. 
     The reflectors  130 ,  130   a ,  130   b ,  130   c ,  130   d , and  230  may be provided in a variety of shapes that can realize an intended light distribution by allowing a portion of the light L 1  that has been generated by the first light source  111  to be radiated directly to the front of the substrate  110  while the remaining portion of the light L 1  is reflected to the side and rear. 
     As illustrated in  FIG. 6A , the reflector  130   a  may be configured as a curved reflector plate, in which a lower end thereof is fixed to the substrate  110 , and an upper end thereof is oriented toward the first light source  111 . 
     In addition, as illustrated in  FIG. 6B , the reflector  130   b  may be configured as a reflector plate that has a vertical section  131  and an inclined section  132 . The vertical section  131  vertically extends a certain height from a lower end thereof, which is fixed to the substrate  110 . The inclined section  132  extends at a certain angle from an upper end of the vertical section  131  toward the first light source  111 . 
     Furthermore, as illustrated in  FIG. 6C , the reflector  130   c  may be configured as a reflector plate that has a lower curved section  131  and an inclined section  132 . The lower curved section  131  is curved from a lower end thereof, which is fixed to the substrate  110 , toward the first light source  111 . The inclined section  132  extends at a certain angle from an upper end of the lower curved section  133  toward the first light source  111 . 
     In addition, as illustrated in  FIG. 6D , the reflector  130   d  may be configured as a reflector plate that has a vertical section  131  and an upper curved section  134 . The vertical section  131  vertically extends a certain height from a lower end thereof, which is fixed to the substrate  110 . The upper curved section  134  is curved from an upper end of the vertical section  131  toward the first light source  111 . 
     The vertical section  131  and the inclined section  132  are connected to each other at a joint C 1 , the lower curved section  133  and the inclined section  132  are connected to each other at a joint C 2 , and the vertical section  131  and the upper curved section  134  are connected to each other at a joint C 3 . The joints C 1 , C 2 , and C 3  be positioned at the same height as or higher than the first light source  111  so that the light L 1  that is generated by the first light source  111  can be reflected to the side or rear. 
     Although the joints C 1 , C 2 , and C 3  have been described as being integrally formed with respective reflectors  130   b ,  130   c , and  130   d , other configuration is also possible. The joints C 1 , C 2 , and C 3  may be provided such that they can be assembled to the respective reflectors  130   b ,  130   c , and  130   d , depending on the design of the reflectors. 
     In each of the reflectors  130 ,  130   a ,  130   b ,  130   c ,  130   d , and  230 , which are provided in a variety of shapes as described above, the free end extends to the position directly above the first light source  111 , such that a portion of the light L 1  that is generated by the first light source  111  is radiated to the side and rear after being reflected by the reflector and the remaining portion of the light L 1  is radiated to the front together with the light L 2  that is generated by the second light source  112 . 
     In addition, the reflectors  130 ,  130   a ,  130   b ,  130   c ,  130   d , and  230  may be made of a resin or a metal, and one or more reflecting layers  135  may be attached on the outer surface of the reflectors  130 ,  130   a ,  130   b ,  130   c ,  130   d , and  230  to increase reflection efficiency when reflecting light that is generated by a light source. 
     The reflecting layer  135  may be formed on the surface of the reflector with a certain thickness. For this, a reflective material, such as aluminum (Al) or chromium (Cr), may be applied to the surface of the reflector by a variety of methods, such as deposition, anodizing, or plating. 
     Although the reflecting layer  135  has been illustrated and described as being formed with a certain thickness on the entire outer surface of the reflector such that it can reflect a large portion of the light that is generated by the first and second light sources  111  and  112 , other configuration is also possible. For example, the reflecting layer  135  may be formed only on the outer surface of the reflectors  130  and  230 , which corresponds to the first light source  111 , such that only the light L 1  that is generated by the first light source  111  can be reflected. 
     In case the reflectors  130  and  230  are made of a metal, an insulating material or insulation may be provided between the surface of the substrate  110  and the lower end of the reflectors  130  and  230  to prevent short circuits. 
     The reflector  130  of this embodiment is provided as a reflector plate having a certain height, as illustrated in  FIG. 2  to  FIG. 8  and  FIG. 10  to  FIG. 16 . The lower end of the reflector may be fixedly assembled to the substrate  110  or the board  114  by a variety of methods. An exemplary method is illustrated in  FIG. 7 . 
     As illustrated in  FIG. 7A , the reflector  130  may have a hook  136  on the lower end thereof. The hook  136  may be fitted into an assembly hole  116 , which penetrates the substrate  110 . In this configuration, the hook  136  generates a holding force, thereby preventing the lower end of the reflector  130  from being dislodged. 
     As illustrated in  FIG. 7B , the reflector  130  has a coupling section  137 , which is bent from the lower end thereof to the side. The coupling section  137  may be fastened to a coupling hole  117 , which penetrates the substrate  110 , via a fastening member  137   a.    
     Although the coupling section  137  has been illustrated as being bent toward the second light source  112  such that it can increase reflection efficiency by reducing interference with the light that is generated by the first light source  111 , other configuration is also possible. For example, the coupling section  137  may be bent toward the first light source  111 . 
     In addition, as illustrated in  FIG. 7C , the reflector  130  has a fitting protrusion  138  on the lower end thereof. The fitting protrusion  138  is fitted into a recess  118 , which is depressed into the upper surface of the substrate  110  to a certain depth, and is fixedly bonded thereto via an adhesive  138   a.    
     Here, each of the assembly hole  116 , the coupling hole  117 , and the recess  118 , which are formed in the substrate  110 , should be configured such that it does not overlap a pattern circuit, which is printed on the upper surface of the substrate in order to supply electrical power to the first light source  111 . Two or more hooks  136  corresponding to the assembly holes  116  may be provided on the lower end of the reflector  130  such that they are spaced apart from each other at a certain interval. Two or more coupling sections  137  corresponding to the coupling holes  117  and two or more fitting protrusions  138  corresponding to the recesses  118  may be provided on the lower end of the reflector  130  in a similar manner. 
     In another embodiment of the LED illumination apparatus  500  of the present invention, as illustrated in  FIG. 16  and  FIG. 17 , the reflector  130  may be supported by support members  250 , which connect the reflector  130  to the light-transmitting cover  140 , with the lower end thereof being fixed to the upper surface of the substrate  110 . 
     For this, the support members  250  may include a vertical member  251 , which has a certain height, and horizontal members  252 , which are connected to the lower end of the vertical member  251 . Specifically, the vertical member  251  has a certain length, the upper end of the vertical member  251  is connected to the light-transmitting cover  140 , and the lower end of the vertical member  251  is connected to the horizontal members  252 , which are disposed across the reflector  130 . 
     The horizontal members  252  may be provided as a plurality of members, which extend in transverse directions from the center of the reflector  130 . The point at which the horizontal members  252  are connected to each other may be connected to the lower end of the vertical member  251 , and the horizontal members  252  may be radially disposed in order to maintain the balance of force. 
     The sum of the vertical length of the vertical member  251  and the height of the reflector  130  may the same as or greater than the maximum height from the substrate  110  to the light-transmitting cover  140 , and the upper end of the vertical member  251  may be connected to the center of the light-transmitting cover  140 . Furthermore, the lower end of the vertical member  251  may be disposed on the center of the reflector  130 . 
     Consequently, when the light-transmitting cover  140  and the heat sink  120  are coupled to each other, the horizontal member  252  and the reflector  130  are pressed and supported downward by the vertical member  251  so that the lower end of the reflector  130  remains in contact with the upper surface of the substrate  110 , thereby locating the reflector  130  in the boundary area between the first light source  111  and the second light source  112 . 
     The reflector  130 , which is connected to the light-transmitting cover  140  by the support members  250 , may be formed integrally with the light-transmitting cover  140 , or may be configured such that the intermediate portion or the upper end of the vertical member  251  is detachably assembled to the light-transmitting cover  140 . 
     In an exemplary embodiment, the vertical member  251  may be configured as two separate members, in which the adjoining ends of the two members are detachably assembled to each other via screw fastening or interference fitting. 
     As illustrated in  FIG. 18  to  FIG. 23 , in other embodiments of the LED illumination apparatuses  600  and  700  of the present invention, the reflector  130 , which reflects light that is generated by the first light source  111  to the side or rear, may be spaced apart a certain height from the substrate  110 . 
     For this, support members  250  and spacer members  260  are provided such that the lower end of the reflector  130  is located in a boundary area between the first light source  111  and the second light source  112 . 
     As described above, the support members  250  may include a vertical member  251  and one or more horizontal members  252 . An end of the vertical member  251  is connected to the light-transmitting cover  140 , and the horizontal members  252  extend from the lower end of the vertical member  251  as shown in  FIG. 18  and  FIG. 19 . 
     Like the support members  250  illustrated in  FIG. 16  and  FIG. 17 , the support members  250  are configured such that the vertical member  251  extends a certain height and the horizontal members  252  are connected to the lower end of the vertical member  251 . The upper end of the vertical member  251  is connected to the light-transmitting cover  140 , and the lower end of the vertical member  251  is connected to the horizontal members  252 , which are disposed across the reflector  130 . 
     The horizontal members  252  may be provided as a plurality of members, which extend in transverse directions from the center of the reflector  130 . The point at which the horizontal members  252  are connected to each other is connected to the lower end of the vertical member  251 . The horizontal members  252  may be radially disposed in order to maintain the balance of force. 
     The sum of the vertical length of the vertical member  251  and the height of the reflector  130  may be smaller than the maximum height from the substrate  110  to the light-transmitting cover  140  such that the lower end of the reflector  130  is spaced apart a certain length from the substrate  110 , thereby defining a space S 3  between the lower end of the reflector  130  and the upper surface of the substrate  110 . 
     Consequently, when the light-transmitting cover  140  is coupled to the heat sink  120 , the horizontal members  252  and the reflector  130  are disposed in the space S in the light-transmitting cover  140  while they are spaced apart a certain height from the upper surface of the substrate  110  by the vertical member  251 . 
     The reflector  130 , which is connected to the light-transmitting cover  140  by the support members  250 , may be formed integrally with the light-transmitting cover  140 , or may be configured such that the intermediate portion or the upper end of the vertical member  251  is detachably assembled to the light-transmitting cover  140 . 
     In an exemplary embodiment, the vertical member  251  may be configured as two separate members, in which the adjoining ends of the two members may be detachably assembled to each other via screw fastening or interference fitting. 
     Another configuration of the reflector  130  and the substrate  110  is illustrated in  FIG. 21  and  FIG. 22 , wherein the reflector  130  is spaced apart a certain height from the substrate  110  to define a space S 3  between the lower end of the reflector  130  and the upper surface of the substrate  110 . 
     Here, provided are one or more spacer members  260  having a certain height, which connect the lower end of the reflector  130  to the upper end of the substrate  110 , such that the reflector  130  is spaced apart a certain height from the substrate  110 . For structural stability, the spacer members  260  may be two or more members, which are radially disposed. 
     The upper end of the spacer member  260  is connected to the lower end of the reflector  130  and the lower end of the spacer member  260  is fixed to the upper surface of the substrate  110 . It should be appreciated that the lower end of the spacer member  260  may be fixed to the substrate  110  by a plurality of structures, as illustrated in  FIG. 7 . 
       FIG. 20  and  FIG. 23  illustrate the light reflected by the reflector  130  in case the reflector  130  is spaced apart a certain height from the substrate  110  via the support members  250  or the spacer members  260 . 
     As illustrated in  FIG. 20  and  FIG. 23 , a portion of the light that is generated by the first light source  111  is radiated to the side and rear of the substrate  110  after being reflected by the outer surface of the reflector  130 , and the remaining portion of the light L 1  is radiated toward the area above the second light source  112  after being reflected from the inner surface of the reflector  130 , or is directly radiated toward the area above the second light source  112 . Consequently, the light that is generated by the first light source  111  is radiated on all of the center, side, and rear of the light-transmitting cover  140  without being reflected to the side and rear of the reflector. In this manner, the light can be uniformly radiated, rather than being concentrated in a specific area. 
     The LED illumination apparatuses  800  and  900  may be provided according to further exemplary embodiments of the present invention. As illustrated in  FIG. 25  to  FIG. 29 , the light-transmitting cover  140  may include two sections, i.e. a first cover  141  and a second cover  142 . The first and second covers  141  and  142  are coupled to each other via the upper end of the reflector  230 . 
     The lower end of the reflector  230  is disposed on the boundary area between the first light source  111  and the second light source  112 , and the upper end of the reflector  230  is fixedly connected to the light-transmitting cover  140 . For this, the extension  231  of the reflector  230  diverges and extends a certain length toward the first cover  141  and toward the second cover  142 . 
     The extension  231  is in contact with and meshed with an end of the first cover  141  and an end of the second cover  142 , and serves to couple the first and second cover  141  and  142  to each other. For this, a stepped portion  232 , which is depressed to a certain depth, is formed in an end of the first cover  141 , which is coupled with the extension  231 . The other stepped portion  232 , having the same configuration, is formed in an end of the second cover  142 , which is coupled with the extension  231 . 
     It should be understood that the extension  231  may be fixed by a variety of structures, including a structure in which the extension  231  is fixed to the stepped portions of the first cover  141  and the second cover  142  via an adhesive, and a structure in which the extension  231  is fitted into the recesses that are respectively formed in an end of the first cover  141  and in an end of second cover  142 . 
     In the reflector  230  having the upper end connected to the light-transmitting cover  140 , the lower end of the reflector  230  is in contact with the upper surface of the substrate  110 . More particularly, the lower end of the reflector  230  is in contact with the boundary area between the first light source  111  and the second light source  112 , or is spaced apart a certain height from the substrate  110  while being disposed in the boundary area between the first and second light sources  111  and  112 . 
     In case the lower end of the reflector  230  is in contact with the substrate, as illustrated in  FIG. 24  and  FIG. 25 , the space S inside the light-transmitting cover  140  is divided into two sections by the reflector  230 . Consequently, the light L 1  that is generated by the first light source  111  is radiated to the side and rear of the substrate  110  after being reflected by the outer surface of the reflector  230 , whereas the light L 2  that is generated by the second light source  112  is radiated toward the second cover  142  after being reflected by the inner surface of the reflector  230 , or is directly radiated toward the second cover  142  (see  FIG. 26 ). 
     In addition, as illustrated in  FIG. 27  and  FIG. 28 , in case the lower end of the reflector  230  is located in the boundary area between the first light source  111  and the second light source  112  and is spaced apart a certain height from the substrate  110 , the space S of the light-transmitting cover  140  is divided into the spaces S 1 , S 2 , and S 3 . In the space S 1 , the light that is generated by the first light source  111  is reflected to the side and rear by the outer surface of the reflector  230 . In the space S 2 , the light is reflected by the inner surface of the reflector  230 , or is directly radiated toward the second cover  142 . In addition, the light that is generated by the first light source  111  is radiated toward the second cover  142  by passing through the space S 3 . The light that is generated by the first light source  111  and the second light source  112  is radiated along various paths illustrated in  FIG. 29  toward the first cover  141  and the second cover  142 . 
     In this embodiment, the lower end of the reflector  230  is spaced apart a certain height from the substrate  110  for the same reason as described in the aforementioned embodiments. Specifically, the light that is generated by the first light source  111  is also radiated toward the second cover  142  through the space S 3  instead of being entirely reflected to the side and rear by the reflector. In this manner, the light can be uniformly radiated, rather than being concentrated in a specific area. 
     The reflectors  130  and  230  of these embodiments may have a plurality of cross-sectional shapes, as illustrated in  FIG. 8 . 
     Specifically, as illustrated in  FIG. 8A , the reflectors  130  and  230  may be configured as a reflector plate, which has a cavity along the circular boundary area defined between the first light source  111  and the second light source  112 . 
     As illustrated in  FIG. 8B , the reflector  130   e  may be configured as a reflector plate that has a wavy cross-sectional shape. Specifically, waves span for a certain period such that the light that is generated by the first light source  111  or the second light source  112  can be spread again in the direction parallel to the substrate  110 . 
     In addition, as illustrated in  FIG. 8C , the reflector  130   f  may be configured as a reflector plate that has a toothed cross-sectional shape, in which teeth span for a certain period such that the light that is generated by the first light source  111  or the second light source  112  can be spread again in the direction parallel to the substrate  110 . 
     In the LED illumination apparatuses  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 ,  900 ,  1100 , and  1200  according to exemplary embodiments, each of the reflectors  130  and  230  is disposed in the boundary area between the first light source  111  and the second light source  112 . When the first light source  111  and the second light source  112  are turned on in response to the application of external power, a portion of the light L 1  that is generated by the first light source  111  is reflected by the outer surface of the reflector, the cross section of which is curved or inclined toward the first light source  111 , so that the portion of the light L 1  travels toward the side or rear, whereas the remaining portion of the light L 1  travels toward the light-transmitting cover  140  without being reflected by the reflector. 
     In addition, the light L 2  that is generated by the second light source  112  travels toward the light-transmitting cover  140  after being reflected by the inner surface of the reflector or without being interfered by the reflector. Consequently, the LED illumination apparatuses  100 ,  200 ,  300 ,  400 ,  500 ,  600 ,  700 ,  800 ,  900 ,  1100 , and  1200  of these embodiments can realize light distribution ( FIG. 9C ), which is the same as light distribution ( FIG. 9B ) that can be produced from an incandescent lamp, and produce an increased angular range of 270° or more. 
     Referring to  FIG. 30  to  FIG. 36 , in the LED illumination apparatus  1000  according to another exemplary embodiment of the present invention, the reflector  1030  has an inclined surface, which reflects light that is generated by a light source, and a horizontal surface on which the light source is disposed. 
     Here, the LED illumination apparatus  1000  may include the substrate  110 , the first light source  111 , the second light source  112 , and the reflector  1030 . 
     In the reflector  1030  having the horizontal surface and the inclined surface, descriptions of the substrate on which the reflector  130  is disposed, the heat sink, and the light-transmitting cover are omitted since they are similar as those described above. In addition, the same reference numerals and symbols are used to designate the substrate, the heat sink, and the light-transmitting cover. 
     The reflector  1030  illustrated in  FIG. 30  to  FIG. 36  may be disposed on the upper portion of the substrate  110 , and serve to reflect the light that is generated by the light sources  111  and  112  to the side and rear. 
     The reflector  1030  may be disposed in the inner area of the substrate  110  with a certain height, and a second light source  112  may be disposed on the upper surface of the reflector  1030 . Consequently, a first light source  111  including a plurality of first LED devices may be disposed in the boundary area of the substrate  110 , outside of the reflector  1030 , and the second light source  112  including a plurality of second LED devices may be disposed on the upper surface of the reflector  1030 . A second surface  1033 , which forms the side surface of the reflector  1030 , is inclined at a certain angle to the first light source  111  such that the light that is generated by the first light source  111  can be reflected to the side and rear of the substrate  110 . 
     Here, the plurality of second LED light devices  112 , which are disposed on the upper surface of the reflector  1030 , may be disposed between respective first LED light devices  111 , which are disposed along the periphery of the substrate  110 , as illustrated in  FIG. 32 . This is intended to make the light that is generated by the first LED light devices  111  and the light that is generated by the second LED light devices  112  to share the entire area of the light-transmitting cover  140 , so that overall intensity of light is uniform. 
     The reflector  1030  may have a multistage structure, which is bent inward. Specifically, a first surface  1034  is formed in the middle of the height of the reflector  1030 , such that the LED light devices are disposed on the first surface  1034 , and a second surface  1035  reflects the light that is generated by the LED light devices disposed on the first surface to the side and rear. This is intended to increase the uniformity of the overall intensity of light by disposing the LED light devices on the first surface  1034 , which have different heights, such that the light that is generated by the LED light devices can be reflected by the second surface  1035 . 
     In case the reflector  1030  has the multistage structure, an upper stage  1031  and a lower stage  1032  are arranged concentrically, with the cross-sectional area of the upper stage being smaller than that of the lower stage. This is intended to allow a portion of the light L 2  that is generated by the LED light devices, which are disposed on the first surface  1034 , to be reflected by the second surface  1035 , which forms the side surface of the upper stage, to the side and rear, whereas the remaining portion of the light L 2  is directly radiated toward the light-transmitting cover  140  without being reflected by the reflector  1030 . 
     Although the reflector  1030  has been illustrated as having the two-stage structure, other configuration is also possible. For example, it should be understood that the reflector may have three or more stories in which the first surface  1034  and the second surfaces  1033  and  1035  are repeated. In addition, although the first surface  1034  has been illustrated as a horizontal surface, other configuration is also possible. For example, it should be understood that the first surface  1034  may be an inclined surface that has a downward slope at a certain angle. 
     For the sake of explanation, a description is given below of a two-stage structure of the reflector  1030 . In the reflector  1030 , a first stage  1032  has the first surface  1034  and the second surface  1033 , and a second stage  1031  has the second surface  1035  and an upper surface  1036 . 
     In this embodiment, the first light source  111  is disposed in the boundary area of the substrate  110 , the second light source  112  is disposed on the first surface  1034  of the first stage  1032 , and a third light source  113  is disposed on the upper surface  1036  of the second stage  1031 . The first, second, and third light sources  111 ,  112 , and  113  are electrically connected to the substrate  110 . The second surface  1033 , which forms the side surface of the first stage  1032 , and the second surface  1035 , which forms the side surface of the second stage  1031 , have the same cross-sectional shape, and are inclined at the same certain angle toward the first light source  111  and the second light source  112 . 
     Consequently, the second surface  1033 , which forms the side surface of the first stage  1032 , reflects a portion of the light that is generated by the first light source  111  to the side and rear, and the second surface  1035 , which forms the side surface of the second stage  1031 , reflects a portion of the light that is generated by the second light source  112  to the side and rear. Light that is generated by the third light source  113 , which is disposed on the upper surface  1036  of the second stage  1031 , is directly radiated toward the light-transmitting cover  140  without being reflected by the reflector  1030 . 
     In the LED illumination apparatus  1000  of this embodiment, the first light source  111 , the second light source  112 , and the third light source  113  are located at different heights, such that the light L 1  that is generated by the first light source  111  is radiated on the lower portion of the light-transmitting cover  140  (as designated by dotted lines in  FIG. 33 ), the light L 2  that is generated by the second light source  112  is radiated on the intermediate portion of the light-transmitting cover  140  (as designated by dashed-dotted lines  FIG. 33 ), and the light L 3  that is generated by the third light source  113  is radiated on the central area of the light-transmitting cover  140  (as designated by solid lines in  FIG. 33 ). 
     Consequently, in the LED illumination apparatus  1000  of this embodiment, the light that is generated by the light sources is radiated to the side and rear of the substrate  110  after being reflected by respective second surfaces  1033  and  1035 , and the light sources are located at different heights to radiate light on the entire area of the light-transmitting cover  140 . This, as a result, can increase the uniformity of the intensity of light and realize light distribution similar to that of an incandescent lamp. 
     Here, the light sources may be formed as a chip-on-board (COB) assembly, in which a plurality of LED chips are integrated on a board, an LED package including lead frames, or a combination thereof (See  FIG. 10  to  FIG. 15 .) 
     In the reflectors  1030 ,  1030   a ,  1030   b ,  1030   c ,  1030   d , and  1030   e  of this embodiment, the second surfaces  1033  and  1035 , which form the side surface, may be provided in a variety of shapes that can realize an intended light distribution by allowing a portion of the light L 1  and L 2  that is generated by the first light source  111  and the second light source  112  to be radiated directly to the front of the substrate  110  while the remaining portion of the light L 1  and L 2  is reflected to the side and rear. 
     Specifically, as illustrated in  FIG. 34A , the reflector  1030   a  may have a generally conical shape. Specifically, the second surface  1033 , which forms the side surface of the first stage  1032 , is a straight line that is inclined toward the first light source  111 . The second surface  1035 , which forms the side surface of the second stage  1031 , is a straight line that is inclined toward the second light source  112 . 
     In the reflector  1030   b  illustrated in  FIG. 34B , the second surface  1033  forms the side surface of the first stage  1032 , and is curved such that the upper end thereof is oriented toward the first light source  111 . The second surface  1035  forms the side surface of the second stage  1031 , and is curved such that the upper end thereof is oriented toward the second light source  112 . 
     In the reflector  1030   c  illustrated in  FIG. 34C , the second surface  1033  forms the side surface of the first stage  1032 , and may include a vertical section  1033   a , which extends a certain height from the lower end thereof, and an inclined section  1033   b , which extends obliquely at a certain angle from the upper end of the vertical section  1033   a  toward the first light source  111 . In addition, the second surface  1035  forms the side surface of the second stage  1031 , and includes a vertical section  1035   a , which extends a certain height from the lower end thereof, and an inclined section  1035   b , which extends obliquely at a certain angle from the upper end of the vertical section  1035   a  toward the second light source  112 . 
     In the reflector  1030   d  illustrated in  FIG. 34D , the second surface  1033  forms the side surface of the first stage  1032 . The second surface  1033  may include a lower curved section  1033   c , which is curved from the lower end thereof toward the first light source  111 , and an inclined section  1033   b , which extends obliquely at a certain angle from the upper end of the lower curved section  1033   c  toward the first light source  111 . In addition, the second surface  1035  forms the side surface of the second stage  1031 , and may include a lower curved section  1035   c , which is curved from the lower end thereof toward the second light source  112 , and an inclined section  1035   b , which extends obliquely at a certain angle from the upper end of the lower curved section  1035   c  toward the second light source  112 . 
     Furthermore, in the reflector  1030   e  illustrated in  FIG. 34E , the second surface  1033  forms the side surface of the first stage  1032 . The second surface  1033  may include a vertical section  1035   a , which extends a certain height from the lower end thereof, and an upper curved section  1033   d , which is curved from the upper end of the vertical section  1033   a  toward the first light source  111 . In addition, the second surface  1035  forms the side surface of the second stage  1031 , and may include a vertical section  1035   a , which extends a certain height from the lower end thereof, and an upper curved section  1035   d , which is curved from the upper end of the vertical section  1035   a  toward the second light source  112 . 
     Here, a joint C 1  at which the inclined section  1033   b  meets the vertical section  1033   a , a joint C 2  at which the inclined section  1033   a  meets the lower curved section  1033   c , and a joint C 3  at which the upper curved section  1033   d  meets the vertical section  1033   a  may be positioned at the same height as or higher than the first light source  111  so that the light L 1  that is generated by the first light source  111  can be reflected to the side or rear. Also, a joint C 1  at which the inclined section  1035   b  meets the vertical section  1035   a , a joint C 2  at which the inclined section  1035   b  meets the lower curved section  1035   c , and a joint C 3  at which the upper curved section  1035   d  meets the vertical section  1035   a  may be positioned at the same height as or higher than the second light source  112  so that the light L 2  that is generated by the first light source  1022  can be reflected to the side or rear. 
     Although the joints C 1 , C 2 , and C 3  have been described as being integrally formed with respective reflectors, other configuration is also possible. The joints C 1 , C 2 , and C 3  may be assembled to the respective reflectors, depending on the design of the reflectors. 
     In each of the reflectors  1030 ,  1030   a ,  1030   b ,  1030   c ,  1030   d , and  1030   e , which are provided in a variety of shapes as described above, the free end of the first surface extends to the position directly above the first light source  111  and the free end of the second surface extends to the position directly above the second light source  112 , such that a portion of the light L 1  that is generated by the first light source  111  and a portion of the light L 2  that is generated by the first light source  1022  are radiated to the side and rear after being reflected by the reflector while the remaining portions of the light L 1  and L 2  are radiated to the front. 
     The reflectors  1030 ,  1030   a ,  1030   b ,  1030   c ,  1030   d , and  1030   e  may be made of a resin or a metal. One or more reflecting layers  1070  may be formed on the outer surface of the reflector to increase reflection efficiency when reflecting the light that is generated by the light source. 
     The reflecting layer  1070  may be formed on the surface of the reflector with a certain thickness. For this, a reflective material, such as aluminum (Al) or chromium (Cr), may be applied to the surface of the reflector by a variety of methods, such as deposition, anodizing, or plating. 
     In case the reflectors  1030 ,  1030   a ,  1030   b ,  1030   c ,  1030   d , and  1030   e  are made of a metal, an insulating material or insulation may be provided between the surface of the substrate  110  and the lower end of the reflector in order to prevent short circuits. 
     The reflector  1030  of this embodiment has a multistage structure, as illustrated in  FIG. 30  to  FIG. 34 . The lower end of the reflector may be fixedly assembled to the substrate  110  by a variety of methods. An exemplary method is illustrated in  FIG. 35 . 
     As illustrated in  FIG. 35A , the reflector  1030  has a hook  1039  on the lower end thereof. The hook  136  is fitted into an assembly hole  116 , which penetrates the substrate  110 . In this configuration, the hook  1039  generates a holding force, thereby fixing the lower end of the reflector  1030  to the upper surface of the substrate  110 . 
     As illustrated in  FIG. 35B , the reflector  1030  has a coupling section  1037 , which is bent from the lower end thereof to the side. The coupling section  1037  may be fastened to a coupling hole  117 , which penetrates the substrate  110 , via a fastening member  1037   a.    
     In addition, as illustrated in  FIG. 35C , the reflector  1030  has a fitting protrusion  1038  on the lower end thereof. The fitting protrusion  1038  is fitted into a recess  118 , which is depressed into the upper surface of the substrate  110  to a certain depth, and is fixedly bonded thereto via an adhesive  1038   a.    
     Here, each of the assembly hole  116 , the coupling hole  117 , and the recess  118 , which is formed in the substrate  110 , should be configured such that it does not overlap a pattern circuit, which is printed on the upper surface of the substrate in order to supply electrical power to the light sources  111 ,  112 , and  113 . Two or more hooks  1039  corresponding to the assembly holes  116  may be provided on the lower end of the reflector  1030 , such that they are spaced apart from each other at a certain interval. Two or more coupling sections  1037  corresponding to the coupling holes  117  and two or more fitting protrusions  1038  corresponding to the recesses  118  may be provided on the lower end of the reflector  1030  in a similar manner. 
     The reflector  1030  of this embodiment may have a plurality of cross-sectional shapes, as illustrated in  FIG. 36 . 
     Specifically, in a reflector  1030   f  illustrated in  FIG. 36A , the second surface  1033 , which reflects a portion of the light that is generated by the first light source  111  to the front or rear, and the second surface  1035 , which reflects a portion of the light that is generated by the second light source  112  to the front or rear, may have a conical cross-sectional shape. 
     In a reflector  1030   g  illustrated in  FIG. 36B , the second surface  1033  and the second surface  1035  may have a wavy cross-sectional shape. Specifically, waves span for a certain period such that the light that is generated by the first light source  111  and the light that is generated by the first light source  1022  can be spread again in the direction parallel to the substrate  110 . 
     In addition, in a reflector  1030   h  illustrated in  FIG. 36C , the second surface  1033  and the second surface  1035  may have a toothed cross-sectional shape. Specifically, teeth span for a certain period such that the light that is generated by the first light source  111  and the light that is generated by the second light source  112  can be spread again in the direction parallel to the substrate  110 . 
     In the LED illumination apparatus  1000  of this embodiment, the reflector  1030  is disposed in the inner area of the substrate  110 . When the light sources are turned in response to the application of external power, a portion of the light L 1  that is generated by the first light source  111  is reflected by the second surface  1033  of the reflector  1030 , the cross section of which is curved or inclined toward the first light source  111 , so that the portion of the light L 1  travels to the side or rear, whereas the remaining portion of the light L 1  travels toward the light-transmitting cover  140  without being reflected by the reflector  1030 . 
     In addition, a portion of the light L 2  that is generated by the second light source  112  travels to the side or rear of the substrate after being reflected by the second surface  1035  of the reflector  1030 , the cross section of the second surface  1035  being curved or inclined toward the second light source  112 , whereas the remaining portion of the light L 2  travels toward the light-transmitting cover  140  without being reflected by the reflector  1030 . 
     Furthermore, the light that is generated by the third light source  113 , which is disposed on the upper surface  1036  in the highest stage, directly travels toward the transparent cover without being reflected by the reflector. Consequently, the LED illumination apparatus  1000  of this embodiment can realize light distribution (see  FIG. 9C ) similar to light distribution (see  FIG. 9B ) that can be produced from an incandescent lamp, and produce an increased angular range of 270° or more. 
     Moreover, the light sources  111 ,  112 , and  113  are located at different heights due to the multistage structure of the reflector  1030 . Consequently, the light that is generated by the light sources can be radiated toward the light-transmitting cover  140 , thereby realizing uniform intensity of light. 
       FIG. 37  to  FIG. 43  illustrate an LED illumination apparatus  1100  according to another exemplary embodiment of the present invention. The LED illumination apparatus  1100  according to another embodiment of the present invention is technically characterized in that the first light source  111  and the second light source  112 , which are disposed on the substrate  110 , are separated from each other by the reflector  230  such that light that is generated by the first light source  111  and light that is generated by the second light source  112  pass through portions of a cover  140  having different transmittances, thereby realizing a variety of light distribution patterns. 
     As illustrated in  FIG. 37  to  FIG. 43 , the LED illumination apparatus  1100  may include the light sources  111  and  112 , the reflector  230 , and the cover  140 . 
     The light sources  111  and  112 , including a plurality of first LED devices  111  and a plurality of second LED devices  112 , which are disposed on the substrate  110 , generate light in response to the application of electrical power. The first light source  111  and the second light source  112  are separated by the reflector  230  such that the first light source  111  is disposed on the peripheral portion of the substrate  110  and the second light source  112  is disposed on the central portion of the substrate. 
     Consequently, the light that is generated by the second light source  112  is radiated forward, that is, through the second cover  142 . A portion of the light that is generated by the first light source  111  is directly radiated toward the first cover  141 , through which the light portion is then radiated to the outside, and another portion of the light that is generated by the first light source  111  is reflected by the reflector  230  toward the first cover  141 , through which the light portion is then radiated to the side and the rear. 
     Here, the light that is generated by the first light source  111  and the light that is generated by the second light source  112  are divided by the reflector  230  so that the light generated by the first light source  111  is radiated toward the first cover  141  and the light generated by the second light source  112  is radiated toward the second cover  142 . 
     Here, as shown in  FIG. 10  to  FIG. 15 , the first light source  111  and the second light source  112  may be formed as a chip-on-board (COB) assembly, in which a plurality of LED chips are integrated on the board, an LED package including lead frames, or a combination thereof. 
     The substrate  110  may be a circuit board member, which has a certain circuit pattern formed on the upper surface thereof, such that the circuit pattern is electrically connected to external power, which is supplied through a power cable (not shown), and is electrically connected to the light sources. 
     The substrate  110  may be disposed on the upper surface of a heat sink  120 , with the heat dissipation pad  121  being interposed between the substrate  110  and the heat sink  120 . Although the substrate  110  has been illustrated and described as having the form of a disc conforming to the shape of the mounting area, i.e. the upper surface of the heat sink  120 , other configuration is also possible. Alternatively, the substrate  110  may be formed as a polygonal plate, such as a triangular or rectangular plate. 
     In addition, although the substrate  110  has been illustrated and described as being bonded to the upper surface of the heat sink via the heat dissipation pad  121 , other configuration is also possible. It should be understood that the substrate  110  may be detachably assembled to the upper surface of the heat sink  120  using a fastening member. 
     The heat sink  120  may be made of a metal having excellent heat conductivity, such as Al, such that it can dissipate the heat that is generated when the light sources  111  and  112 , which are disposed on the substrate  110 , emit light to the outside. 
     The heat sink  120  may have a plurality of heat dissipation fins on the outer surface thereof to increase heat dissipation efficiency by increasing the heat dissipation area. 
     Here, the shape of the heat sink  120  should be optimally designed to reduce interference with the portion of the light that is generated by the first light source  111 . Otherwise, the portion of the light encounters interference by colliding with the heat sink  120  while traveling backward after being reflected by the outer surface of the reflector  230 . 
     For this, the heat sink  120  may have the guide surface  124  on the outer circumference thereof, the guide surface  124  being inclined downward at a certain angle to guide the light that is generated by the first light source  11  in the backward direction. The guide surface  124  serves to increase the area through which the light travels in the backward direction, thereby increasing the angular range of radiation of the light while a portion of the light that is generated by the light sources is reflected to the side and rear by the reflector  230 . 
     The reflector  230  may be disposed on the surface of the substrate  110 , and may serve to reflect light that is generated by the first light source  111  to the side and rear. 
     The reflector  230  may be formed as a reflector plate having a certain height. The lower end of the reflector  230  may be disposed on the boundary area between the second light source  112 , which is disposed on the inner area of the substrate  110 , and the first light source  111 , which is disposed on the peripheral area of the substrate, and the upper end of the reflector  230  connects the first and second covers  141  and  142  of the cover  140  to each other. 
     The reflector  230  may have an extension  231  at the upper end thereof. The extension  231  may be bent, diverge, and extend a certain length toward the first cover  141  and toward the second cover  142 , respectively, such that they connect the first and the second covers  141  and  142  to each other. Consequently, the space S defined inside the cover  140  is partitioned by the reflector  230 . 
     The light that is generated by the first light source  111  is radiated to the outside through the first cover  141 , whereas the light that is generated by the second light source  112  is radiated to the outside through the second cover  142 . 
     The reflector  230  may be provided in a variety of shapes that can realize the intended light distribution by allowing a portion of the light that is generated by the first light source  111  to be radiated directly toward the first cover  141  while the remaining portion of the light is reflected to the side and rear. 
     The reflector  230  may be configured as a curved reflector plate, in which the lower end thereof is fixed to the substrate  110 , and the upper end thereof is oriented toward the second light source  112 . 
     However, it should be understood that the shape of the reflector  230  of this embodiment is not limited thereto, but the reflector  230  may be provided in a variety of shapes that include at least one of a vertical section, an inclined section and a curve section as shown in  FIG. 6 . 
     The reflector  230  may be made of a resin or a metal, and one or more reflecting layers may be attached on the outer surface of the reflector  230  to increase reflection efficiency when reflecting light that is generated by the light source. 
     The reflecting layer may be formed on the surface of the reflector with a certain thickness. For this, a reflective material, such Al or Cr, can be applied to the surface of the reflector by a variety of methods, such as deposition, anodizing, or plating. 
     The reflecting layer may be formed with a certain thickness on the entire outer surface of the reflector such that it can reflect a large portion of the light that is generated by the first and second light sources  111  and  112 , or may be formed only on the outer surface of the reflector  230 , which corresponds to the first light source  111 , such that only the light that is generated by the first light source  111  is reflected. 
     In case the reflector  230  is made of a metal, an insulating material or insulation may be provided between the surface of the substrate  110  and the lower end of the reflector  230  in order to prevent short circuits. 
     It should also be understood that the lower end of the reflector  230 , which is disposed on the boundary area between the peripheral area and the inner area of the substrate  110 , can be fixed and/or assembled to the substrate using a variety of methods. 
     As an example thereof, a holding force may be generated by fitting a hook, which is provided on the lower end of the reflector, into an assembly hole, which is formed in the substrate. Alternatively, the reflector may have a coupling section on the lower end thereof, the coupling section being bent to a side. The coupling section may be screwed into the substrate using a fastening member such as a bolt. The lower end of the reflector may also be fixedly bonded to the upper surface of the substrate using an insulating adhesive as illustrated in  FIG. 7 . 
     A light-transmitting cover  140  having a space S therein is provided on the upper surface of the outer circumference of the heat sink  120 . The light-transmitting cover  140  radiates the light that is emitted from the first and second light sources  111  and  112  to the outside while protecting the light sources from the external environment. 
     The cover  140  may include two parts, i.e. a first cover  141 , which radiates the light that is generated by the first light source  111  to the outside, and a second cover  142 , which radiates the light that is generated by the second light source  112  to the outside. The first and second covers  141  and  142  are coupled to each other via the upper end of the reflector  230 , that is, the extension  231  of the reflector  230 . 
     The space S is then divided into a first space, which is surrounded by the second cover  142  and the inner surface of the reflector  230 , and a second space which is surrounded by the first cover  142  and the outer surface of the reflector  230 . 
     The extension  231  may be formed on the upper end of the reflector  230  such that it diverges and extends a certain length toward the first cover  141  and the second cover  142 . The extension  231  is in contact with and meshed with an end of the first cover  141  and an end of the second cover  142 , and serves to couple the first and second cover  141  and  142  to each other as shown in  FIG. 39 . 
     For this, stepped portions  143 , which are depressed to a certain depth, may be formed in corresponding ends of the first cover  141  and the second cover  142 , such that the extension  231  can be meshed with the stepped portions  143 . 
     As the extension  231  is meshed with the stepped portions  143  formed in the ends of the first and second covers  141  and  142 , the covers  141  and  142  may be connected to each other via the extension  231 . 
     The first and second covers  141  and  142  may serve as light-transmitting covers. The first and second covers  141  and  142  may also serve as light spreading covers in order to radiate light that is generated by the first and second light sources  111  and  112  to the outside by spreading it. 
     With the first and second covers  141  and  142  being connected together, the lower end of the cover  140  is positioned below the substrate  110 , which is disposed on the heat sink  120 , such that the light that is generated by the first light source  111  can be reflected by the reflector  230  to the rear of the substrate  110  so that it can be radiated across a wider angular range of radiation. 
     Here, it should be understood that the extension  231  may be fixed by a variety of structures, including a structure by which the extension  231  is fixed to the stepped portions  143  of the first cover  141  and the second cover  142  via an adhesive, and a structure by which the extension  231  is fitted into the recesses that are respectively formed in the end of the first cover  141  and in the end of second cover  142 . 
     The stepped portions  143  may be coupled with the extension  231  by ultrasonic fusion, which has the advantages that fusion time is short, bonding strength is excellent, operation is very simple since additional components, such as a bolt or screw, are not required, and a very clear appearance can be obtained. 
     Furthermore, since neither a process nor a space for fastening a bolt, a screw, or the like is required, the thickness of the connection in which the extension  231  and the stepped portion  143  are coupled to each other may be formed such that it has the same thickness as that of the first or second cover  141  or  142 . 
     In the cover  140 , which radiates light that is generated by the light source to the outside, the distribution of the light that is radiated to the outside varies depending on the transmittance of the cover  140 . As illustrated in  FIG. 43A , the light that has passed through the cover  140  exhibits a common light distribution pattern (solid line). When the transmittance of the cover  140  is decreased, the light distribution pattern is changed to the shape indicated by the dotted line in  FIG. 43A . In contrast, when the transmittance of the cover  140  is increased, the light distribution pattern is changed to the shape indicated by the dashed-dotted line in  FIG. 43A . 
     Based on this principle, this embodiment may realize a variety of light distribution patterns by imparting different transmittances to the first and second covers  141  and  142 . 
     The second cover  142  may have a transmittance that is lower than that of the first cover  141  in order to realize the light distribution pattern that is indicated by the solid line in FIG.  43 B. Alternatively, the second cover  142  may have a transmittance that is higher than that of the first cover  141  in order to realize the light distribution pattern that is indicated by the solid line in  FIG. 43C . 
     In this embodiment, it is easy to impart the first and second covers  141  and  142  of the cover  140  with different transmittances, since the cover  140  is divided into the two covers  141  and  142 , and the two covers  141  and  142  are connected to each other via the upper end of the reflector  230 . 
     Here, the first and second covers  141  and  142  may be configured such that they have different transmittances by imparting the first cover  141  and the second cover  142  with different thicknesses t 1  and t 2 , respectively, although the material of the first cover  141  has the same transmittance as that of the material of the second cover  142 . Then, the light distribution pattern illustrated in  FIG. 43 b    is realized by setting the thickness t 1  of the second cover  142  to be greater than the thickness t 2  of the first cover  141 , or the light distribution pattern illustrated in  FIG. 43 c    is realized by setting the thickness t 1  of the second cover  142  to be less than the thickness t 2  of the first cover  141 . This is because a thicker cover has lower transmittance, whereas a thinner cover has higher transmittance. 
     As an alternative, covers having different transmittances may be used as the first and second covers  141  and  142 . The cover typically serves to spread light by allowing the light to pass through, and the transmittance of the cover varies depending on the content of the spreading agent and multiple additives, which are mixed in the course of manufacturing the cover. 
     Therefore, the first and second covers  141  and  142  may be implemented as two types of covers having different content of the spreading agent and additives, and may then be connected to each other via the upper end of the reflector  230 . 
     Accordingly, the LED illumination apparatus of this embodiment can realize multiple light distribution patterns in a product. 
     If the transmittance of the cover is increased, degree of spreading decreases even though light transmission efficiency increases. If the transmittance of the cover is decreased, light transmission efficiency decreases even though degree of spreading increases. In this embodiment, it is possible to realize an LED illumination apparatus that has various light distribution patterns by implementing the first and second covers  141  and  142  using the covers having different transmittances. 
     The cover  140  that radiates light that is generated by the light source to the outside may contain a fluorescent material  170 , which converts the light that is generated by light source into white light. LEDs that are typically used as the light source are implemented as at least one of red, green and blue LEDs. While the light that is generated by the LEDs is passing through the fluorescent material, it undergoes frequency conversion and is then converted into white light. 
     In order to realize the white light, an LED that generates red, green or blue color was mounted on the substrate, and the fluorescent material may be injected into the space that is formed by the cover. 
     However, this embodiment can produce white light by disposing the fluorescent material  170 , which can convert the color of the light that is generated by the LED into white, inside the cover  140 . 
     As an example thereof, as illustrated in  FIG. 40 , the first light source  111  and the second light source  112 , which are mounted on the substrate  110 , are implemented as LEDs that generate blue light, and a yellow phosphor having a certain thickness is applied on the inner surface of the first and second covers  141  and  142  in order to radiate white light to the outside. 
     Accordingly, blue light L 1  that is generated by the first light source  111  and blue light L 2  that is generated by the second light source  112  undergo frequency conversion while they are passing through the fluorescent material  170 , which is applied on the inner surfaces of the first and second covers  141  and  142 . As a result, white light W is radiated to the outside. 
     As an alternative, it is possible to produce white light by adding a fluorescent material, which is selected according to the color of light that is generated by the LEDs, to the first and second covers  141  and  142  in the process of fabricating the first and second covers  141  and  142 . 
     Another shape is illustrated in  FIG. 41 . Specifically, a first frequency conversion cover  241  and a second frequency conversion cover  242  are employed in place of the respective first and second covers  141  and  142  such that they can convert light that is generated by the first and second light sources  111  and  112  into white light, and a separate light spreading cover  145  is disposed outside the first and second frequency conversion covers  241  and  242 . 
     Consequently, light B 1  that is generated by the first light source  111  and light B 2  that is generated by the second light source  112  are converted into respective white light W 1  and W 2  while passing through the first frequency conversion cover  241  and the second frequency conversion cover  242 . The white light W 1  and W 2  is spread while passing through the light spreading cover  145 , thereby being radiated to the outside as spread white light W 3 . 
     The first and second light sources  111  and  112  may be implemented as LED light sources, each of which may include at least one of red, green and blue LEDs, and the first and second frequency conversion covers  241  and  242  may contain a fluorescent material, which converts light that is generated by the LEDs into white light. 
     In the LED illumination apparatus  1100  of this embodiment, as illustrated in  FIG. 42 , the first light source  111  and the second light source  112 , which are separated by the reflector  230  such that the first light source  111  is disposed on the peripheral portion of the substrate  110  and the second light source  112  is disposed on the central portion of the substrate  110 , may be implemented with respective LED types that generate different colors of light or have different color temperatures. 
     That is, in this embodiment, the cover  140  is divided into the two parts, i.e. the first cover  141  and the second cover  142 , and the space S inside the cover  140  is partitioned by the reflector  230 , such that the light that is generated by the first light source  111  is radiated towards the first cover  141  and the light that is generation by the second light source  112  is radiated towards the second cover  142 . 
     Accordingly, when the first light source  111  and the second light source  112  are implemented with respective LED types that emit different colors of light or different color temperatures, the light that is radiated towards the first cover  141  and the light that is radiated towards the second cover  142  form different types of light. 
     As an example, the first light source may be implemented as blue LEDs, whereas the second light source may be implemented as red LEDs. The LED illumination apparatus  1100  of this embodiment then radiates blue light to the front of the substrate  110  (i.e. in the upward direction in  FIG. 42 ) and red light to the side and rear of the substrate  110  (i.e. in the lateral and downward directions in  FIG. 42 ). 
     As another example, the first light source may be implemented as warm white LEDs, whereas the second light source may be implemented as cool white LEDs. The LED illumination apparatus  1100  of this embodiment then radiates warm white light to the front of the substrate  110  (i.e. in the upward direction in  FIG. 42 ) and cool white light to the side and rear of the substrate  110  (i.e. in the lateral and downward directions in  FIG. 42 ). 
     As such, this embodiment makes it possible to produce a variety of illumination patterns by radiating a variety of colors or color temperatures by mounting different types of light sources on the inner area and on the peripheral area of the substrate  110 . 
     According to this embodiment as above, it is possible to radiate a portion of light that is generated by the light sources toward the side and rear of the illumination apparatus, thereby increasing the angular range of radiation. Consequently, the distribution of light may be made similar to that of an incandescent lamp. 
     In addition, since the light that is generated by the first light source and the light that is generated by the second light source are radiated to the outside through the respective first and second covers, which are partitioned by the reflector and have different transmittances, a variety of light distribution patterns can be realized. 
     Furthermore, this embodiment can facilitate fabrication and increase productivity, since the fluorescent material, which converts the light that is generated by the LED into white light, is contained in the cover. 
     Moreover, in this embodiment, one LED illumination apparatus can achieve a variety of illumination patterns according to the mood, since the light that is generated by the first light source and the light that is generated by the second light source are separated from each other by the reflector, and the first and second light sources are designed to generate different types of light. 
     As illustrated in  FIG. 44  to  FIG. 50 , the LED illumination apparatus according to another embodiment of the present invention may include the light sources  111  and  112 , the reflector  230 , the cover  140 , and the heat sink  120 . 
     The light sources  111  and  112  may disposed on the substrate  110  to generate light in response to the application of electrical power, and include a plurality of first LED devices and a plurality of second LED devices. The first light source  111  and the second light source  112  are separated from each other by the lower portion of the reflector  230  such that the first light source  111  is disposed in the peripheral area of the substrate  110  and the second light source  112  is disposed in the inner area of the substrate  110 . 
     Then, light that is generated by the second light source  112  is radiated to the front through the cover  140 , that is, the second cover  142 . A portion of light that is generated by the first light source  111  is radiated directly toward the first cover  141 , through which it is radiated to the outside, and another portion of the light that is generated by the first light source  111  is reflected by the reflector  230  toward the first cover  141 , through which it is then radiated to the side and rear. 
     The light that is generated by the first light source  111  and the light that is generated by the second light source  112  are divided by the reflector  230  so that the light from the first light source  111  is radiated toward the first cover  141  and the light from the second light source  112  is radiated toward the second cover  142 . 
     Here, the light sources may be provided as a chip-on-board (COB) assembly, in which a plurality of LED chips are integrated on a board, an LED package including lead frames, or a combination thereof (See  FIG. 10  to  FIG. 15 .) 
     The substrate  110  is a circuit board member, which has a certain circuit pattern formed on the upper surface thereof, such that the circuit pattern is electrically connected to external power, which is supplied through a power cable (not shown), and is electrically connected to the light sources. The substrate  110  is disposed on the mounting area  122 , i.e. the upper surface of the heat sink  120  via a fastening member. 
     Although the substrate  110  has been illustrated and described as having the form of a disc conforming to the shape of the mounting area  122 , i.e. the upper surface of the heat sink  120 , other configuration is also possible. Alternatively, the substrate  110  may be formed as a polygonal plate, such as a triangular or rectangular plate. 
     In addition, although the substrate  110  has been illustrated and described as being bonded to the mounting area of the heat sink  120  via the fastening member, other configuration is also possible. It should be understood that the substrate  110  may be detachably assembled to the mounting area of the heat sink  120  using a heat dissipation pad. 
     The heat sink  120  may be made of a metal, such as Al, having excellent heat conductivity, such that it can dissipate heat that is generated when the light sources  111  and  112  emit light to the outside. 
     The upper surface of the heat sink  120  described above forms the flat mounting area  122  such that the substrate  110  may be disposed thereon. The guide surface  124  may be formed on the upper portion of the heat sink  120  and have a downward slope at a certain angle to reduce the interference of a portion of the light that would otherwise collide with the heat sink  120  while traveling backward after being reflected by the reflector. 
     The guide surface  124  may be gradually inclined from the edge of the mounting surface  122  to the bottom of guide surface  124  to reduce the interference of a portion of the light that is generated by the first light source  111 , which is disposed in the peripheral area of the substrate  110 . Otherwise, the portion of the light would encounter interference by colliding with the heat sink  120  while traveling backward after being reflected by the reflector. 
     Consequently, this can increase the area illuminated by the light that is traveling backward after being reflected by the reflector, thereby increasing the angular range of the light. Since the guide surface  124  has a downward slope at a certain angle or more, even though a portion of the light that is reflected by the reflector  230  collides with the guide surface  124 , it can still sustain its function to guide the light portion to the rear. 
     Here, one or more reflecting layers may be formed on the guide surface  124  to reduce the loss of the light that collides with the guide surface  124 . 
     The guide surface  124  may be formed on top of the heat sink  120  such that the maximum outer diameter of the guide surface  124  is the same as or smaller than the maximum outer diameter of the cover  140 . 
     As illustrated in  FIG. 44 , in the guide surface  124  that has a downward slope from the mounting surface  122 , the point C at which the lower end of the guide surface  124  is formed is positioned on the same vertical plane as that of the outermost point A in the side of the cover  140  or is positioned inside the outermost point A. 
     This is intended to decrease the total loss of light by reducing interference of the light that travels backward after being reflected by the reflector  230 . Otherwise, the light encounters interference by colliding with the guide surface  124 . 
     A base  128  is coupled to the lower end of the heat sink  120 , and is provided with a sock like connector  129 , which can supply external power to a power supply (not shown). The connector  129  is fabricated such that it has the same shape as that of the socket of an incandescent lamp, so that the LED illumination apparatus can substitute a typical incandescent lamp. 
     The reflector  230  may be disposed on the upper portion of the substrate  110 , and serve to reflect the light that is generated by the first light source  111  to the side and rear. 
     The reflector  230  may be formed as a reflector plate having a certain height, and may be disposed on the boundary area between the first light source  111 , which is disposed on the peripheral area of the substrate  110 , and the second light source  112 , which is disposed on the inner area of the substrate  110 . The upper end of the reflector  230  connects the first and second covers  141  and  142  of the cover  140  to each other. 
     The reflector  230  may have the extension  231  on the upper end thereof, which diverges and extends a certain length toward the first cover  141  and toward the second cover  142 . The extension  231  is meshed with the stepped portion  143  in an end of the first cover  141  and with the stepped portion  143  in an end of the second cover  142 , thereby connecting the first and second covers  141  and  142  to each other. 
     The reflector  230  may be provided in a variety of shapes that can realize an intended light distribution by allowing a portion of the light that is generated by the second light source  112  to be radiated directly to the front of the substrate  110  while the remaining portion of the light is reflected to the side and rear so that the angular range of radiation is increased. 
     Specifically, the reflector  230  may be implemented as a reflector plate, which has a curved section such that the upper end thereof is bent more toward the second light source that the lower end thereof, which is disposed on the boundary area between the first and second light sources  111  and  112 . 
     However, it should be understood that the shape of the reflector  230  of this embodiment is not limited thereto, but the reflector  230  may be provided in a variety of shapes that include at least one of a vertical section, an inclined section, a curve section and combinations thereof as shown in  FIG. 6 . 
     The reflector  230  may be made of a resin or a metal, and one or more reflecting layers may be attached on the outer surface of the reflector  230  to increase reflection efficiency when reflecting light that is generated by the light source. 
     The reflecting layer may be formed on the surface of the reflector  230  with a certain thickness. For this, a reflective material, such Al or Cr, may be applied to the surface of the reflector by a variety of methods, such as deposition, anodizing, or plating. 
     It should also be understood that the lower end of the reflector  230  may be spaced apart at a certain interval from the substrate  110  even though it may be fixed to the substrate  110 , as shown in  FIG. 27  to  FIG. 29 . 
     The cover  140 , which radiates light that is generated by the first and second light sources  111  and  112  to the outside while protecting the light sources  111  and  112  from external environment, is provided over the heat sink  120 . 
     The cover  140  may include the first cover  141 , which radiates the light that is generated by the first light source  111  to the outside, and the second cover  142 , which radiates the light that is generated by the second light source  112  to the outside. The first and second covers  141  and  142  may be coupled to each other via the upper end of the reflector  230 , that is, the extension  231  of the reflector  230 . 
     The extension  231 , which is formed on the upper end of the reflector  230 , may be meshed with an end of the first cover  141  and an end of the second cover  142 . For this, a stepped portion  232 , which is depressed to a certain depth, may be formed in an end of the first cover  141 , and the other stepped portion  232 , having the same configuration, may be formed in an end of the second cover  142 . 
     Since the extension  231  is meshed with the stepped portions  143  formed in the ends of the first and second covers  141  and  142 , the first and second covers  141  and  142  may be connected to each other via the extension  231 . 
     The extension  231  may be fixed by a variety of structures, including a structure by which the extension  231  is fixed to the stepped portions of the first cover  141  and the second cover  142  via an adhesive, and a structure by which the extension  231  is fitted to a certain depth into an end of the first cover  141  and into an end of second cover  142 . 
     The stepped portions  143  may be coupled with the extension  231  by ultrasonic fusion which has the advantages that fusion time is short, bonding strength is excellent, operation is very simple since additional components, such as a bolt or screw, are not required, and a very clear appearance can be obtained. 
     The first and second covers  141  and  142  may be implemented as light-transmitting covers, and/or be formed as a light spreading cover in order to radiate light that is generated by the first and second light sources  111  and  112  to the outside by spreading. 
     As illustrated in  FIGS. 44 to 49 , with the first and second covers  141  and  142  being connected together, the lower end of the cover  140  may be positioned below the substrate  110 , which is disposed on the heat sink  120 , and be coupled to the portion of the guide surface  124  that lies between the ends of the guide surface  124 . Alternatively, as illustrated in  FIG. 50 , the lower end of the cover  141  may be coupled to the mounting area  122 . 
     For this, a fitting section  144  may be formed on the lower end of the cover  140 , i.e. the lower end of the first cover  141 . As illustrated in  FIG. 44 , the fitting section  144  extends inward a certain length. In the corresponding portion of the guide surface  124 , a coupling groove  126  may be provided. The coupling groove  126  is formed along the outer circumference and is depressed inward to a certain depth. When the heat sink  120  and the cover  140  are coupled to each other, the fitting section  144  is fitted into the coupling groove  126 , such that the cover  140  can stay in the fixed position above the heat sink  120 . 
     As another shape, as illustrated in  FIG. 49 , a coupling recess  226  may be formed between the two ends of the guide surface  124  of the heat sink  10  such that it is depressed inward to a certain depth. As illustrated in  FIG. 50 , the coupling recess  226  may be formed adjacent to the edge of the mounting surface  122  such that it is depressed downward to a certain depth. The lower end of the first cover  141  has a vertical section  244 , which extends downward a certain length such that it can be fitted into the coupling groove  226 . The coupling groove  226  has at least one fitting recess  226   a  and at least one fitting lug  226   b , and the vertical section  244  has a fitting lug  244   a  and a fitting recess  244   b , which correspond to the fitting recess  226   a  and the fitting lug  226   b , respectively. When the heat sink  120  and the cover  140  are coupled to each other, the vertical section  244  is fixedly inserted into the coupling groove  226  such that the fitting lug  244   a  and the fitting recess  244   b  of the vertical section  244  are engaged with the fitting recess  226   a  and the fitting lug  226   b  of the coupling groove  226 . 
     Even though the cover  140  may have a hemispherical overall shape, the cover  140  may have an aspheric overall shape, as illustrated in  FIG. 44  to  FIG. 50 . 
     In particular, the second cover  142 , which is positioned above the second light source  112 , may have an aspheric shape. Typically, in LED illumination apparatuses, the cover that surrounds the light source is hemispherical. When the second cover  142  is aspheric, the length between the second light source  112 , which is disposed on the substrate  110 , and the second cover  142  is relatively decreased. This, as a result, decreases the distance that the light that is generated by the second light source  112  travels before colliding with the second cover  142 , thereby increasing the overall light efficiency of the illumination apparatus. 
     The cover  140  that radiates the light that is generated by the light source to the outside may contain the fluorescent material  170 , which converts the light that is generated by light source into white light. LEDs that are typically used as the light source are implemented as at least one of red, green and blue LEDs. While the light that is generated by the LEDs is passing through the fluorescent material, it undergoes frequency conversion and is then converted into white light. 
     In order to realize the white light, an LED that generates red, green or blue color may be mounted on the substrate, and the fluorescent material was injected into the space that is formed by the cover. 
     However, this embodiment can produce white light by disposing the fluorescent material  170 , which can convert the color of the light that is generated by the LED into white, inside the cover  140 . 
     An example thereof, as illustrated in  FIG. 47 , the first light source  111  and the second light source  112 , which are mounted on the substrate  110 , are implemented as LEDs that generate blue light B 1  and B 2 , and a yellow phosphor having a certain thickness is applied on the inner surface of the first and second covers  141  and  142  in order to radiate white light W to the outside. 
     Accordingly, blue light B 1  that is generated by the first light source  111  and blue light B 2  that is generated by the second light source  112  undergo frequency conversion while they are passing through the fluorescent material  170 , which is applied on the inner surfaces of the first and second covers  141  and  142 . As a result, the white light W is radiated to the outside. 
     As an alternative, it is possible to produce white light by adding a fluorescent material, which is selected according to the color of light that is generated by the LEDs, to the first and second covers  141  and  142  in the process of fabricating the first and second covers  141  and  142 . 
     Another shape is illustrated in  FIG. 47 . Specifically, the first frequency conversion cover  241  and the second frequency conversion cover  242  are employed in place of the respective first and second covers  141  and  142  such that they can convert the light that is generated by the first and second light sources  111  and  112  into white light, and the separate light spreading cover  145  is disposed outside the first and second frequency conversion cover  241  and  242 . 
     Consequently, light B 1  that is generated by the first light source  111  and light B 2  that is generated by the second light source  112  are converted into respective white light W 1  and W 2  while passing through the first frequency conversion cover  241  and the second frequency conversion cover  242 . The white light W 1  and W 2  is then spread while passing through the light spreading cover  145 , thereby being radiated to the outside as spread white light W 3 . 
     The first and second light sources  111  and  112  are implemented as LED light sources each of which may include at least one of red, green and blue LEDs, and the first and second frequency conversion covers  241  and  242  contain a fluorescent material, which converts light that is generated by the LEDs into white light. 
     Even though the first and second frequency conversion covers  241  and  242  may contain the same type of fluorescent material, a person having ordinary skill in the art may add different types of fluorescent materials in order to adjust the color temperature of illumination. In an example, when the first and second light sources  111  and  112  generate blue light, the first frequency conversion cover  241  contains yellow phosphor, whereas the second frequency conversion cover  242  contains green phosphor. 
     According to this embodiment as above, it is possible to radiate a portion of light that is generated by the light sources toward the side and rear of the illumination apparatus, thereby increasing the angular range of radiation. Consequently, the distribution of light can be made similar to that of an incandescent lamp. 
     In addition, in this embodiment, the cover is provided above the heat sink on which the substrate is mounted in order to guide the light that is generated by the light source to the rear and reduce the interference of the light so that the loss of the light that is radiated to the rear is reduced, thereby increasing the entire light efficiency. 
     Furthermore, in this embodiment, the cover, which surrounds the light source, is formed aspheric to decrease the distance between the light source and the cover so that the loss of the light that is radiated to the front is reduced, thereby increasing the entire light efficiency. 
     Moreover, in this embodiment, the fluorescent material, which converts the light that is generated by the light source into white light, is contained in the cover side. This, consequently, facilitates fabrication and improves productivity. 
     While the present invention has been illustrated and described with reference to the certain exemplary embodiments thereof, it will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention and such changes fall within the scope of the appended claims.