Abstract:
The present invention relates to an LED surface light-emitting device for easy shielding, and a manufacturing method thereof, and includes: an integrated type rear-surface case part having an accommodation space portion open toward the front surface portion thereof, wherein a substrate equipped with LEDs is accommodated in the accommodation space portion; a diffusion panel which covers the open front surface portion of the rear-surface case part, and diffuses light of the LEDs to be a surface light source; and a front-surface window frame, the rear surface of which is coupled to the boundary of the front surface portion of the rear-surface case part, with the diffusion panel located on the rear-surface case part. The present invention is configured as a single body without openings to prevent dust and insects from coming therein, and thus can prevent brightness from decreasing according to use.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of International Application No. PCT/KR2012/011493 filed on Dec. 26, 2012, which claims a priority to Korean Application No. 10-2011-0146916 filed on Dec. 30, 2011, which applications are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present invention relates to an LED surface light-emitting device for easy shielding and a method of manufacturing the same, and more particularly to an LED surface light-emitting device for easy shielding installed on a ceiling of an interior of a building to prevent introduction of foreign substances such as dust or insects and a method of manufacturing the same. 
     BACKGROUND ART 
     In recent years, development of lighting devices using an LED as a light source has been accelerated, considering that existing lighting devices consume much electric power and should be frequently replaced due to a short life span thereof. 
     Currently, lighting devices using an LED as a light source are replacing existing fluorescent lights or light bulbs. The lighting devices are installed on a ceiling of an interior of a building and illuminate a relatively wide area. 
     However, the lighting devices using surface light emission as lighting devices using LEDs according to the related art have different intensities of illumination at central portions and peripheral portions thereof. 
     This is because the light of LEDs disposed at the central portions can be emitted to the light dispersing plate on the front side, but the light of LEDs located at the peripheral portions cannot be directly input to the light dispersing plate as it is reflected by a frame on a lateral side of the LEDs. 
     Further, the surface light-emitting devices using LEDs according to the related art accommodate a substrate to which LEDs are mounted, and a window frame formed of a metal is used as a frame fixed to a ceiling. Then, since the window frame should be formed by separately manufacturing edge frames and be assembled, productivity is very low. 
     There are very many examples of surface light-emitting devices forming a window frame by assembling divided linear frames, and one of the examples is Korean Patent No. 10-0976274. 
     It is disclosed in Korean Patent No. 10-0976274 that a first main frame and a second main frame are coupled to each other using bolts to manufacture a main frame, that is, a window frame, and in surface light-emitting devices using LEDs according to the related art, and metallic linear frames are coupled to each other by bolts to manufacture a window frame providing a space for accommodating a substrate to which LEDs are mounted. 
     A gap is generated between the first main frame and the second main frame, and dust may be introduced through the gap or insects such as mayflies may enter the window frame. 
     The foreign substances such as dust and insects gather on an upper surface of a light dispersing plate, that is, on an inside of the lighting device, and accordingly, the brightness of the lighting device becomes gradually darker. 
     This problem can be solved by disassembling the lighting device and cleaning the light dispersing plate, but because the light dispersing plate is inserted into and fixed to a central portion of a window frame when being assembled in the main frame, that is, the window frame, it actually cannot be disassembled. 
     Accordingly, even when the life span of the LEDs is  10  years or more, the brightness of the lighting device is gradually reduced through introduction of foreign substances, making it difficult to use the lighting device for a long time. 
     As described above, because the main frame is assembled according to the related art, much time is spent in the assembly process and productivity is low. In particular, because the price of the lighting device is expensive due to use of a metal, an electric light rate reduction effect due to use of LEDs and a lamp exchange cost reduction effect are substantially low, making it difficult to commercialize the device. 
     In addition, because a metallic frame is used, weight is heavy, and when the LED surface light-emitting device installed on a ceiling falls due to a natural disaster such as an earthquake or a shoddy and faulty construction, it may be very dangerous. Further, because the main frame is fixed to a board installation frame of the ceiling using bolts and is fixed using a wire when being installed on the ceiling to prevent falling of the main frame, construction time is very long. 
     SUMMARY 
     Therefore, the present invention has been made in an effort to solve the above-mentioned problems, and the present invention provides an LED surface light-emitting device through which introduction of foreign substance can be prevented and a method of manufacturing the same. 
     The present invention also provides an LED surface light-emitting device through which an assembly process is simplified to improve productivity and a method of manufacturing the same. 
     The present invention also provides an LED surface light-emitting device in which a frame and a substrate support panel are formed of a synthetic resin through injection-molding and which can be commercialized earlier by maximizing an energy saving effect expected when an LED illumination is used and a lamp exchange cost saving effect by lowering the price of the product and a method of manufacturing the same. 
     The present invention also provides an LED surface light-emitting device through which a brightness difference between a central portion and a peripheral portion thereof can be solved and a method of manufacturing the same. 
     The present invention also provides an LED surface light-emitting device for easy shielding which can be easily constructed and has a light weight such that a degree of risk can be reduced even when it falls from the ceiling and a method of manufacturing the same. 
     In accordance with an aspect of the present invention, there is provided an LED surface light-emitting device for easy shielding, including: an integral rear case in which a substrate to which LEDs are mounted is accommodated in an accommodation space opened to a front side; a light dispersing panel covering the opened front side of the rear case, for dispersing light of the LEDs to form a surface light source; and an integral front window frame of which a rear surface is coupled to a periphery of a front surface of the rear case while the light dispersing panel is located on the rear case. 
     In accordance with an aspect of the present invention, there is provided A method of manufacturing an LED surface light-emitting device for easy shielding, the method including: a) manufacturing an integral rear case formed of a synthetic resin through injection-molding to have a bending surface provided on one side of a bottom surface thereof and a support surface flatly extending from the bending surface to a side surface such that an accommodation space having an opened front side is formed, in which a plurality of reinforcing portions and a plurality of coupling supports are located on a rear surface thereof; b) manufacturing a front window frame formed of a synthetic resin through injection-molding to have an opening at a central portion thereof and integrally provided with a plurality of reinforcing portions on a rear surface thereof, the size of the front window frame being larger than the size of the rear case; c) preparing a light dispersing panel for dispersing light such that light is emitted from a surface thereof; d) fixing a substrate to which LEDs are mounted at a predetermined interval within the accommodation space of the rear case; e) stacking the light dispersing panel and the front window frame on the support surface of the rear case in which the substrate is accommodated, and fixing the rear case and the front window frame using a plurality of bolts while the light dispersing panel is interposed between the rear case and the front window frame; and f) locating the power supply unit on the reinforcing portions provided on the rear surface of the rear case and the coupling support, and fixing the power supply to the coupling support using bolts. 
     According to the present invention, because an LED surface light-emitting device is constituted by coupling a single body having no gap, introduction of dust or insects can be prevented and reduction of brightness due to use thereof can be prevented. 
     Further, because the present invention does not require an assembly process as the window frame is integrally manufactured and does not require a process of processing a metal, the process can be very simplified and productivity can be improved. 
     In addition, the frame and the substrate support panel are formed of a synthetic resin through injection-molding, it can be commercialized earlier by maximizing an energy saving effect expected when an LED illumination is used and a lamp exchange cost saving effect by lowering the price of the product 
     Furthermore, because a peripheral portion of the substrate support panel supporting the substrate is processed to be a curved surface or an inclined surface such that light emitted from LEDs located at a periphery of the LEDs can be smoothly provided to the light dispersing plate, a brightness difference between a central portion and a peripheral portion of the surface light-emitting device can be solved. 
     In addition, a danger can be reduced by reducing weight during falling and the device can be easily constructed by a simple operation. In particular, a process of fixing the device with a wire can be omitted to reduce construction time. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded perspective view of an LED surface light-emitting device for easy shielding according to an embodiment of the present invention. 
         FIG. 2  is a view showing a coupled state of  FIG. 1 . 
         FIG. 3  is a sectional view taken along line A-A of  FIG. 2 . 
         FIG. 4  is a perspective view showing a rear surface of a front window frame of  FIG. 1 . 
         FIG. 5  is a partially sectional view of an LED surface light-emitting device for easy shielding according to another embodiment of the present invention. 
         FIG. 6  is a partially sectional view of an LED surface light-emitting device for easy shielding according to another embodiment of the present invention. 
         FIG. 7  is a view showing a front window frame of an LED surface light-emitting device according to another embodiment of the present invention. 
         FIG. 8  is a partially sectional view of a rear case in a state in which a power supply unit is installed. 
         FIG. 9  is a flowchart showing a process of manufacturing an LED surface light-emitting device for easy shielding according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, an LED surface light-emitting device for easy shielding and a method of manufacturing the same according to exemplary embodiments of the present invention will be described with reference to the accompanying drawings. 
       FIG. 1  is an exploded perspective view of an LED surface light-emitting device for easy shielding according to an embodiment of the present invention.  FIG. 2  is a view showing a coupled state of  FIG. 1 .  FIG. 3  is a sectional view taken along line A-A of  FIG. 2 .  FIG. 4  is a perspective view showing a rear surface of a front window frame  40  of  FIG. 1 . 
     Referring to  FIGS. 1 to 4 , an LED surface light-emitting device for easy shielding according to an embodiment of the present invention includes an integral rear case  20  of which one surface is opened, for providing an accommodation space accommodating a substrate  10  to which an LED is mounted, a light dispersing panel  30  covering the rear case  20  such that a periphery of one surface of the light dispersing panel  30  is located at a periphery of an opened surface of the rear case  20 , and a front window frame  40  covering an upper side of the light dispersing panel  30  to be coupled to the rear case  20 , for sealing the rear case  20 . 
     Hereinafter, a configuration and an operation of the embodiment of the present invention will be described in more detail. 
     First, a shape of the rear case  20  has a bending surface  21  formed by bending a periphery of the rear case  20  upwards such that a concave accommodation space is provided on an inside of the bending surface  21 . Then, the upwardly bent bending surface  21  of the rear case  20  is bent from a bottom surface of the accommodation space to be inclined at an angle other than the right angle, and light of some of a plurality of LEDs  11  mounted to the substrate  10 , which are located at the periphery of the substrate  10 , is directly emitted to the light dispersing panel  30  due to the inclination. 
     Accordingly, a surface light-emitting device in which a difference of brightness of the center and brightness of a periphery thereof are not generated can be realized. 
     A flat support surface  22  is formed at an upper portion of the bending surface  21  of the rear case  20  in parallel to the bottom surface of the accommodation space to contact the bottom surface of the front window frame  40  and a plurality of coupling holes  23  are provided in the support surface  22  such that the front window frame  40  is bolt-coupled to the rear case  20  while an upper portion of the rear case  20  is covered by the light dispersing panel  30  and the front window frame  40 . 
     A plurality of reinforcing portions  24  may protrude from a rear surface of the rear case  20  to realize a light and firm structure. As will be described below in detail, the reinforcing portions  24  increase areas of the rear case  20  contacting air, and dissipate heat generated in a power supply unit more easily. 
     A characteristic configuration of the rear case  20  is that the bottom surface of the accommodation space, the bending surface  21 , and the support surface  22  are all integrally formed so that introduction of foreign substances can be prevented. 
     The rear case  20  may be manufactured of a metal, and preferably, may be easily manufactured by injection-molding a synthetic resin. Manufacturing costs can be lowered by using the synthetic resin, and manufacturing time can be shortened. 
     In addition, the rear case  20  can be easily installed by reducing the weight thereof, and a degree of risk can be reduced by reducing damage due to falling of a lighting device. 
     An additive which is advantageous in reflection of light may be added to the synthetic resin rear case  20 , but a sufficient reflection effect for light can be obtained simply by manufacturing a glossy white synthetic resin. 
     The substrate  10  to which a plurality of LEDs  11  are mounted is mounted in the accommodation space of the rear case  20 , and is fixed by bolts. Then, as shown in the drawings, the substrate  10  may be divided into two parts to supply electric power to them, respectively, so that electric power can be supplied only to one of them if necessary to further reduce power consumption. 
     Although it is shown in the drawings that the substrate  10  is divided into two parts, the substrate  10  may not be divided to form one body or may be divided into multiple parts. 
     The light dispersing panel  30  covers the rear case  20  such that a periphery of the rear surface of the light dispersing panel  30  contacts the support surface  22  of the rear case  20  while the substrate  10  is installed in the rear case  20 . Then, a portion of the support surface  22  may be exposed to the outside of the light dispersing panel  30  by making the size of the light dispersing panel  30  smaller than the size of the rear case  20 , that is, the size of the periphery of the support surface  22 . 
     This structure allows a periphery of the rear surface of the front window frame  40  to contact the support frame  22 , and contact portions of the support surface  22  and the front window frame  40  are fixed to each other by coupling bolts. 
     The size of the front window frame  40  is made to be larger than the size of the rear case  20  having the support surface  22  at a periphery thereof such that the support surface  22  is inserted into the rear side of the front window frame  40  to be fixed. 
     That is, a side surface of the front window frame  40  corresponds to a downward bending surface  41  which is downwardly bent, and the downward bending surface  41  is supported by a plurality of reinforcing portions  42  protruding from the rear surface of the window frame  40 . Then, an opening  43  of the front window frame  40  which corresponds to an inside of the reinforcing portions  42  is configured such that the rear case  20  is inserted into the opening  43 , and the rear case  20  may be inserted into an area surrounded by the reinforcing portions  42  to adjust the rear case  20  at a correct position without particularly locating the front window frame  40  and the rear case  20  at correct positions to fix them with bolts. 
     In this way, the reinforcing portions  42  increase a strength of the front window frame  40 , and act as a coupling guide for easy coupling of the front window frame  40  as well. 
     A peripheral portion of the opening  43  of the front window frame  40  corresponds to a curved portion  44  having a predetermined curvature. The curved portion  44  has a visual effect by which an entire structure of the front window frame  40  can be made to be visually thinner and light diffused from the light dispersing panel  30  and emitted to the outside can be reflected from a peripheral area of the opening  42  of the front window frame  40  to prevent shadows. 
     Accordingly, surface-emitted light having a more uniform brightness can be provided. 
     The front window frame  40  may be manufactured of a metal, and may be manufactured of a synthetic resin through injection-molding as in the above-described rear case  20 . The front window frame  40  also may have the above-described effect of the rear case  20 . 
     Then, the front window frame  40  also has a sufficient reflectivity of light using a glossy white synthetic resin. 
     The front window frame  40  and the rear case  20  are coupled to each other using a plurality of bolts on the rear side of the support surface  22  while the front window frame  40  is fitted with the rear case  20 . Then, the light dispersing panel  30  of which a periphery is located between the front window frame  40  and the rear case  20  is also firmly fixed at the same time. 
     Because the rear case  20  and the front window frame  40  are integrally formed in this structure, a gap is not generated and accordingly introduction of foreign substances such as dust or insects can be prevented. 
     If introduction of foreign substance is prevented, an excellent brightness can be continuously maintained without separate management, and accordingly, the LED surface light-emitting device can be continuously used until the LEDs are no longer of use. 
       FIG. 5  is a partially sectional view of an LED surface light-emitting device for easy shielding according to another embodiment of the present invention. 
     Referring to  FIG. 5 , the LED surface light-emitting device for easy shielding according to another embodiment of the present invention has a configuration similar to that of the above-described embodiment of the present invention but further includes an accommodation recess provided along an upper circumference of the support surface  22 , and an O-ring  26  may be inserted into the accommodation recess  25  to further prevent generation of a gap between the front window frame  40  and the rear case  20 . 
       FIG. 6  is a partially sectional view of an LED surface light-emitting device for easy shielding according to another embodiment of the present invention. 
     Referring to  FIG. 6 , the LED surface light-emitting device for easy shielding according to another embodiment of the present invention may be configured such that the bending surface  21  facing the upper side of the rear case  21  may have a curved shape having a predetermined curvature different from that of the example of  FIG. 5 . 
     Then, the curved bending surface  21  minimizes reflection of light emitted from the LEDs  11  at locations adjacent to the curved surface  21  from the curved surface  21 , and prevents lowering of the brightness at a peripheral portion of the curved surface by minimizing the reflection angle even if the light is reflected. 
       FIG. 7  is a view showing a front window frame  40  of an LED surface light-emitting device according to another embodiment of the present invention. 
     Referring to  FIG. 7 , the front window frame  40  according to another embodiment of the present invention is not provided with the downward curved surface  41  due to the difference from the front window frame  40  according to the above-described embodiments, and accordingly has a flatter structure. 
     This structure minimizes a degree by which the device according to the present invention protrudes while being installed in a ceiling, and accordingly, the same level of surface as that of a ceiling panel through which the front window frame  40  is installed on the ceiling may be formed. 
     The front window frame  40  shown in  FIG. 7  is also provided with an opening  43 , and a curved portion  43  is provided at a periphery of the opening  43  to minimize a brightness difference according to locations and reinforcing portions (not shown) are located on a rear surface of the front window frame  40  at locations corresponding to those of the reinforcing portions  42  of the front window frame  40  to guide a coupling location of the rear case  20 . 
     As can be seen from the above-described embodiments, the LED surface light-emitting device according to the present invention having an excellent sealing property may be manufactured by manufacturing the rear case  20 , the light dispersing panel  30 , and the front window frame  40 , which have integral structures, respectively, first, and coupling the rear case  20 , the light dispersing panel, and the front window frame  40  of the integral structures together with the substrate  10 . 
     Because coupling holes for bolts do not need to be processed in the assembly process and the front window frame  40  and the rear case  20  do not need to be manufactured by coupling divided plate structures as well, manufacturing processes thereof can become simple and manufacturing costs can be reduced, which improves productivity. 
       FIG. 8  is a partially sectional view of a rear case unit in a state in which a power supply unit is installed. 
     Referring to  FIG. 8 , the present invention has a mounting structure for a power supply unit  50  which may be applied to the above-described embodiments. 
     A plurality of reinforcing portions  24  are provided on a rear surface of the rear case  20 . The reinforcing portions  24  perform a function of increasing strength of the rear case  20  and function to form passages through which air flows. 
     That is, coupling supports  27  for providing a predetermined coupling area such that the power supply unit  50  is coupled to the coupling supports  27  using bolts are provided at the reinforcing portions  24  at the same height as that of the reinforcing portions  24 , portions of the bottom surface of the power supply unit  50  are supported by the coupling supports  27  and the reinforcing portions  24  and the power supply unit  50  is coupled to the coupling supports  27  using bolts. 
     Then, spaces defined by separations between the reinforcing portions  24  are provided on the lower side of the power supply unit  50 , and smooth convection can be made through the spaces such that heat generated by the power supply unit  50  can be emitted. 
     The easy heat emission of the power supply unit  50  prevents heat generated by the power supply unit  50  from influencing the LEDs  11  and shortening life spans of the LEDs  11  and also prevents a temperature difference between parts of the power supply unit  50  from exceeding a reference value. 
     The heat emission characteristics of the power supply unit  50  can be improved as the heights of the reinforcing portions  24  and the coupling supports  27  increase, in which case it is preferable to form the reinforcing portions  24  and the coupling supports  27  having suitable heights in consideration of the thickness and heat emission characteristics of the device according to the present invention because the overall thickness of the device increases. 
       FIG. 9  is a flowchart showing a process of manufacturing an LED surface light-emitting device for easy shielding according to an embodiment of the present invention. The reference numerals of the component elements will coincide with the reference numerals of the drawings which have been described above. 
     Referring to  FIG. 9 , a method of manufacturing a surface light-emitting device according to an embodiment of the present invention includes: manufacturing a rear case  20  formed of a synthetic resin through injection-molding to have a bending surface  21  and a support surface  22  such that an opened accommodation space is provided on a front side thereof and in which a plurality of reinforcing portions  24  and a plurality of coupling supports  27  are integrally provided on a rear surface thereof (S 91 ); manufacturing a front window frame  40  formed of a synthetic resin through injection-molding to have a size larger than that of the rear case  20 , having an opening  43  at a central portion thereof, and in which a plurality of reinforcing portions  42  are integrally formed on a rear surface thereof (S 92 ), manufacturing a light dispersing panel  30  for diffusing light such that the light is emitted in a surface form (S 93 ); preparing a substrate  10  to which LEDs  11  are mounted at predetermined interval (S 94 ); fixing the substrate  10  within the accommodation space of the rear case  20  (S 95 ); stacking the light dispersing panel  30  and the front window frame  40  on the support surface  22  of the rear case  20  in which the substrate  10  is accommodated, and fixing the rear case  20  and the front window frame  40  using a plurality of bolts while the light dispersing panel  30  is interposed between the rear case  20  and the front window frame  40  (S 96 ); and locating the power supply unit  50  on the reinforcing portions  24  provided on the rear surface of the rear case  20  and the coupling support  27 , and fixing the power supply  50  to the coupling support  27  using bolts (S 97 ). 
     The method of manufacturing an LED surface light-emitting device for easy shielding according to the embodiment of the present invention includes a method of assembling an LED surface light-emitting device for easy shielding, which has been described in the above-described embodiments, and in particular, it is clearly expressed that detailed component elements of the rear case  20  and the front window frame  40  may be manufactured of a synthetic resin as integral bodies. 
     Hereinafter, the method of manufacturing an LED surface light-emitting device for easy shielding according to the embodiment of the present invention, and an operation and an effect which can be expected by the manufacturing method will be described in more detail. 
     First, in step S 91 , a rear case  20  formed of a synthetic resin through injection-molding to have a bending surface  21  and a support surface  22  such that an opened accommodation space is provided on a front side thereof and in which a plurality of reinforcing portions  24  and a plurality of coupling supports  27  are integrally provided on a rear surface thereof is manufactured. 
     Then, the bending surface  21  is provided to easily separate the rear case  20  from an injection mold and also functions to emit light of a uniform brightness to an entire surface of a light dispersing panel  30  as described above. 
     It has been described in detail in the above embodiments that the bending surface  21  may have a flat surface or a curved surface. 
     An additive which may give a glossy white color is added to the synthetic resin, and although the synthetic resin is not particularly limited, a material which is heat-conducive and flexible may contribute to easy coupling afterwards. The flexible synthetic resin may have a problem in strength, but may be reinforced by the reinforcing portions  24 . 
     The curved surface  21 , the support surface  22 , the reinforcing portions  24 , the accommodation recess  25 , and the coupling supports  27  are integrally formed in the injection-molded rear case  20 , and a post-processing process is not required because the coupling holes  23  are also formed at the same time. 
     Accordingly, because a separate processing process is not required during the assembly process, which will be described below, processing time can be shortened. 
     Further, because the rear case  20  is integrally formed without a seam, introduction of foreign substance through a seam can be completely prevented. 
     If necessary, an O-ring  26  accommodated in the accommodation recess  25  is separately manufactured. 
     Next, in step S 92 , a front window frame  40  formed of a synthetic resin through injection-molding to have a size larger than that of the rear case  20  and having an opening  43  at a central portion thereof is manufactured. 
     The front window frame  40  selectively has a downward bending surface and has reinforcing portions  42  on the rear surface thereof, and the reinforcing portions  42  are also formed integrally. 
     As described above, a periphery of the opening  43  is provided with a curved surface  44 , and a separate processing process is not required because the structures are integrally formed. 
     Although omitted in the embodiments, coupling holes (not shown) may be formed in the front window frame  40  to pass through the front window frame  40  and the front window frame  40  may be fixed to a metal frame in a ceiling through the coupling holes. According to the present invention, the rear case  20  and the front window frame  40  are manufactured of a synthetic resin through injection-molding, and accordingly, a separate post-processing process is not required and manufacturing costs can be reduced. 
     Further, safety of the device can be ensured by reducing weight and the device can be easily handled, loaded, and carried. 
     Next, in step S 93 , a light dispersing panel  30  for dispersing light and allows emission of light in surface form is prepared. Any light dispersing panel  30  which disperses light of the LEDs  11  in a surface direction of the light dispersing panel  30  if the light is input to one surface of the light dispersing panel  30  to emit light to an opposite surface of the light input surface of the LEDs  11  may be applied irrespective of a material or shape thereof. 
     Next, in step S 94 , a substrate  10  to which LEDs are mounted at a predetermined interval is prepared. The substrate  10  may be a single body, or may be several divided parts. 
     The LEDs  11  mounted to the substrate  10  may be disposed such that the interval between the LEDs  11  is sufficiently long to lower emission of heat and heat generated by the LEDs is minimized by lowering the outputs thereof. 
     Next, in step S 95 , the substrate  10  is fixed within the accommodation space of the rear case  20 . Then, wires for supplying electric power to the substrate are wired to pass through a rear surface of the rear case  20 . 
     The through-holes for supply of electric power also may be formed during the injection-molding of the rear case  20 , and a process of forming the through-hole through which the wires pass in the rear case  20  of a resin is very easy. 
     Next, in step S 96 , the light dispersing panel  30  and the front window frame  40  are stacked on the support surface  22  of the rear case  20  in which the substrate  10  is accommodated, and the rear case  20  and the front window frame  40  are fixed using a plurality of bolts while the light dispersing panel  30  is interposed between the rear case  20  and the front window frame  40   
     Then, the above-described O-ring  26  may be coupled to the accommodation recess  25  of the support surface  22  while the O-ring  26  is accommodated in the recess  25 , and accordingly, foreign substances are blocked between the rear case  20  and the front window frame  40  such that introduction of foreign substances therebetween is prevented. 
     Then, because the coupling holes provided in the rear case  20  are formed at the same time when the rear case  20  is injection-molded, a separate processing process is not required and accordingly coupling time can be shortened. 
     Next, in step S 97 , the power supply unit  50  is located on the reinforcing portions  24  provided on the rear surface of the rear case  20  and the coupling support  27 , and the power supply  50  is fixed to the coupling support  27  using bolts. According to the manufactured device of the present invention, introduction of foreign substances can be prevented because the foreign substances can be blocked very easily, and 
     It will be appreciated by those skilled in the art to which the present invention pertains that the present invention is not limited to the embodiment and may be variously modified without departing from the spirit of the present invention. 
     Because the present invention provides an LED surface light-emitting device which is shielded to prevent introduction of dust or insects, a degree of illumination of the device can be prevented from being lowered by the foreign substances, which is industrially applicable.