Patent Publication Number: US-2013229802-A1

Title: Planar light-emitting illumination device

Description:
TECHNICAL FIELD 
     The present invention relates to a planar light-emitting illumination device including a plurality of light-emitting semiconductor elements. 
     BACKGROUND ART 
     Patent document 1 discloses a planar light-emitting illumination device in which a plurality of point light sources formed with light-emitting semiconductor elements are arranged. As shown in a plan view of  FIG. 10  and a cross-sectional view of  FIG. 11 , in this planar light-emitting illumination device  549 , a plurality of LEDs  541   a  (light-emitting diode) are arranged on the flat surface of a substrate  541   b  and are held in a housing  545 , and thus the size and the brightness of the planar light-emitting illumination device are enhanced. 
     RELATED ART DOCUMENT 
     Patent Document 
     Patent document 1: JP-A-2010-44922 
     Patent document 2: JP-A-2009-94087 
     DISCLOSURE OF THE INVENTION 
     Problems to be Solved by the Invention 
     However, in the illumination device disclosed in patent document 1, when one of the LEDs  541   a  causes a failure due to a broken wire, the end of its life or the like, in order to replace the failure portion, it is necessary to remove the LED  541   a  soldered to the substrate  541   b  from the substrate  541   b  and to solder a new LED  541   a  again to the substrate  541   b.  Thus, it is complicated to perform an operation of replacing the LED  541   a;  in particular, it is difficult to solder a small LED  541   a  due to its size. Depending on the situation, it may be necessary to replace the substrate  541   b  itself and perform a reflow step on all the LEDs  541   a.    
     The present invention is made in order to solve the foregoing problem; an object of the present invention is to provide a planar light-emitting illumination device in which an operation of replacing a light-emitting semiconductor element is easily performed. 
     Means for Solving the Problem 
     To achieve the above object, according to the present invention, there is provided a planar light-emitting illumination device including: a light-emitting unit that includes: light-emitting semiconductor element; a mounting substrate on which the light-emitting semiconductor element is mounted; and an input terminal conductive to the light-emitting semiconductor element; and a housing that holds a plurality of the light-emitting units and includes a plurality of output terminals through which power from an external power supply is supplied to the light-emitting units, where the light-emitting unit and the housing are removably fixed by a connection unit that connects the input terminal and the output terminal. 
     In this configuration, the power from the external power supply is supplied via the connection unit from the output terminal through the input terminal to the light-emitting unit. A plurality of light-emitting units are fixed to the housing through the connection units. 
     In the planar light-emitting illumination device of the present invention configured as described above, the connection unit is formed with a convex portion and a concave portion that are fitted to each other. 
     In this configuration, through the convex portion and the concave portion, the input terminal and the output terminal are electrically connected to each other, and the convex portion and the concave portion are fitted to each other, and thus the light-emitting unit and the housing are fixed removably and physically. 
     In the planar light-emitting illumination device of the present invention configured as described above, the connection unit includes a conductive magnet. 
     In this configuration, through the conductive magnet, the input terminal and the output terminal are electrically connected to each other, and the light-emitting unit and the housing are fixed removably and physically by the magnetic force of the magnet. 
     In the planar light-emitting illumination device of the present invention configured as described above, the connection unit includes an elastic member, the housing includes a side wall that surrounds the light-emitting units and the input terminal provided on a side surface of the mounting substrate and the output terminal provided in the side wall are connected to each other by utilization of an elastic force of the connection unit. 
     In this configuration, the light-emitting unit is retained within the housing by the elastic force of the elastic member exerted between the side wall surrounding the light-emitting unit and the side surface of the light-emitting unit. 
     In the planar light-emitting illumination device of the present invention configured as described above, a plurality of the light-emitting semiconductor elements are arranged on the mounting substrate. 
     In the planar light-emitting illumination device of the present invention configured as described above, a drive circuit that feeds a control signal to the light-emitting semiconductor element is provided in the light-emitting unit. 
     The planar light-emitting illumination device of the present invention configured as described above includes a diffusion member that diffuses light from the light-emitting semiconductor element. 
     The planar light-emitting illumination device of the present invention configured as described above includes a light collection member that collects light from the light-emitting semiconductor element. 
     Advantages of the Invention 
     In the present invention, when the light-emitting unit is held within the housing, the input terminal and the output terminal are electrically connected through the connection unit, and thus it is possible to supply the power form the external power supply to the light-emitting unit. Moreover, since a plurality of light-emitting unit are held within the housing, and the light-emitting units are removably fixed to the housing through the connection units, it is possible to efficiently perform an operation of removing only a light-emitting unit on which a faulty light-emitting semiconductor element is mounted and of replacing the light-emitting semiconductor element. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       [ FIG. 1 ] An exploded schematic perspective view of a planar light-emitting illumination device according to an embodiment of the present invention; 
       [ FIG. 2 ] An exploded schematic cross-sectional view of the planar light-emitting illumination device shown in  FIG. 1 ; 
       [ FIG. 3 ] A schematic cross-sectional view of a light-emitting unit according to the embodiment of the present invention; 
       [ FIG. 4 ] A partially enlarged schematic plan view of the light-emitting unit according to the embodiment of the present invention; 
       [ FIG. 5 ] An exploded schematic cross-sectional view showing part of a planar light-emitting illumination device according to a variation of the embodiment of the present invention; 
       [ FIG. 6 ] A schematic cross-sectional view of the planar light-emitting illumination device according to the variation of the embodiment of the present invention; 
       [ FIG. 7 ] A partially enlarged schematic cross-sectional view of the planar light-emitting illumination device of  FIG. 6 ; 
       [ FIG. 8 ] An exploded schematic cross-sectional view showing part of a planar light-emitting illumination device according to a variation of the embodiment of the present invention; 
       [ FIG. 9 ] A schematic plan view of the light-emitting unit according to the embodiment of the present invention; 
       [ FIG. 10 ] A schematic plan view of a conventional light-emitting unit; and 
       [ FIG. 11 ] A schematic cross-sectional view of the planar light-emitting illumination device shown in  FIG. 10 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described in detail below with reference to accompanying drawings.  FIG. 1  is an exploded schematic perspective view of a planar light-emitting illumination device according to an embodiment of the present invention;  FIG. 2  is an exploded schematic cross-sectional view of the planar light-emitting illumination device shown in  FIG. 1 . For convenience, member symbols and the like may be omitted; in such a case, other drawings should be referenced. 
     The planar light-emitting illumination device  49  includes a plurality of light-emitting units  41 , a light diffusion cover  43  and a housing  45  that holds them. A plurality of light-emitting units  41  are arranged through connection units  61  within the housing  45 ; the connection unit  61  is formed with a plug  61   a  and an outlet  61   b;  through the connection unit  61 , the light-emitting unit  41  is electrically conductive to the housing  45  and is removably fixed to the housing  45 . Thus, it is possible to remove only a faulty light-emitting unit  41  from the housing  45  and to efficiently replace an LED (light-emitting diode)  41   a  from the removed light-emitting unit  41 . The details of the connection unit  61  will be described later. 
     The light-emitting unit  41  includes the LEDs  41   a,  a mounting substrate  41   b  on which they are mounted and the plug  61   a.  The LED  41   a  is a light-emitting semiconductor element (light source) that emits light; the LED  41   a  is mounted on an electrode formed on the substrate surface of the mounting substrate  41   b.  In order to acquire a sufficient amount of light, a plurality of LEDs  41   a  are packed on the mounting substrate  41   b,  and the light-emitting unit  41  by itself applies planar light. 
     Outside the housing  45 , a control driver (drive circuit)  71  having a supply power adjustment function is provided. The mounting substrate  41   b  is electrically connected to the plug control driver  71  through the plug  61   a  provided on the back surface (the opposite surface to the installation surface of the LEDs  41   a ) of the mounting substrate  41   b  and the outlet  61   b  provided in the housing  45 . In this way, a control signal from the control driver  71  reaches the LED  41   a,  and the light emission of the LED  41   a  is controlled by the control signal. Within the housing  45 , a plurality of outlet  61   b  are spaced regularly, the plugs  61   a  of the light-emitting units  41  are connected to the outlets  61   b  and thus the entire planar light-emitting illumination device  49  can apply large planar light through an aggregation of a plurality of light-emitting units  41 . However, for convenience, in the figure, part of the LEDs  41   a  and the light-emitting units  41  are only shown. 
     Adjacent light-emitting units  41  are arranged within the housing  45  densely without any space between them, and thus it is possible to apply further uniform planar light from the entire light emission surface  50  of the planar light-emitting illumination device  49 . Within the housing  45 , a region where no light-emitting unit  41  is attached to part of the outlets  61   b  arranged is provided, and thus it is possible to reduce power consumption of the entire planar light-emitting illumination device  49 , with the result that it is possible to save energy. 
     The control driver  71  for collectively driving the light-emitting units  41  may be provided outside the housing  45 ; for each of the light-emitting units  41 , the control driver  71  for driving the light-emitting unit  41  may be provided. In this case, as shown in  FIG. 3 , the control driver  71  can be provided in the back surface of the mounting substrate  41   b.    
     The light diffusion cover (diffusion member)  43  is a plate-shaped optical member that covers the light emission surface formed with the aggregation of the light-emitting units  41 , and receives light emitted from the light-emitting units  41  and diffuses the light. Thus, the light diffusion cover  43  diffuses the planar light of the light-emitting units  41 , and thereby can emit the uniform planar light from the entire light emission surface of the planar light-emitting illumination device  49 . 
     The connection unit  61  is formed with the plug  61   a  and the outlet  61   b;  the outlet  61   b  has insertion holes  61   c  that fit to the plug  61   a;  the plug  61   a  fits into the insertion holes  61   c.  An output terminal (not shown) is provided within the insertion holes  61   c;  the output terminal is electrically conductive to the control driver  71 . Thus, the plug  61   a  functions as an input terminal, and, when the plug  61   a  is fitted into the insertion holes  61   c,  the plug  61   a  is connected to the output terminal, with the result that a drive signal from the control driver  71  is fed from the output terminal through the plug  61   a  to the LED  41   a  on the light-emitting unit  41 . 
     Moreover, when the plug  61   a  is inserted into the insertion holes  61   c,  the plug  61   a  is retained within the insertion holes  61   c.  Thus, the light-emitting unit  41  and the housing  45  are fixed physically and removably. In this way, it is possible to perform the operation of replacing the light-emitting unit  41  only by insertion and removal of the plug  61   a  and the outlet  61   b,  with the result that it is possible to efficiently the operation of replacing the LED  41   a  incapable of lighting on the light-emitting unit  41 . 
     The light-emitting unit  41  will now be described in detail.  FIG. 4  is a partially enlarged schematic plan view of the light-emitting unit  41 . As shown in the figure, the LED  41   a  has an anode (positive pole)  31  and a cathode (negative pole)  32 . The anode  31  and the cathode  32  are electrically connected to an anode wiring  31   a  and a cathode wiring  32   a  formed on the mounting substrate  41   b;  the anode wiring  31   a  and the cathode wiring  32   a  are connected to the plug  61   a  provided on the back surface of the mounting substrate  41   b.  The output terminal provided within each of the insertion holes  61   c  is connected to an anode wiring and a cathode wiring within the housing  45 . 
     Thus, when the plug  61   a  is inserted into the insertion holes  61   c,  the anode wiring on the side of the outlet  61   b  becomes electrically conductive to the anode wiring  31   a  on the side of the plug  61   a,  and the cathode wiring on the side of the outlet  61   b  becomes electrically conductive to the cathode wiring  32   a  on the side of the plug  61   a.  Then, the drive signal from the control driver  71  is fed from the output terminal through the plug  61   a  to the LED  41   a  on the light-emitting unit  41 . 
     Other Embodiments  
     The present invention is not limited to the embodiment described above, and various modifications are possible without departing from the spirit of the present invention. 
     For example, as shown in  FIG. 5 , a connector terminal may be used as the connection unit that connects the housing  45  and the light-emitting unit  41 . The connector terminal has a plurality of convex input terminals  261   a  and a plurality of insertion holes  261   c;  the input terminals  261   a  are inserted into the insertion holes  261   c,  and thus the input terminals  261   a  are connected to the output terminal (not shown) provided in the insertion holes  261   c.  With the connector terminal, it is possible to feed a plurality of drive signals from the control driver  71  to the LEDs  41   a.    
     Moreover, as shown in  FIG. 6 , an elastic member may be used as the connection unit that connects the housing  45  and the light-emitting unit  41 . Specifically, as an input terminal  361   a,  an elastic spring terminal is used, and the input terminal  361   a  is provided on the opposite side surface of the mounting substrate  41   b.  Within the housing  45 , a side wall  45   b  that rises from the bottom surface  45   a  of the housing  45  and that surrounds the light-emitting units  41  is provided, and, in a position of the side wall  45   b  opposite the input terminal  361   a,  an output terminal  361   b  is provided. When the light-emitting unit  41  is held in the housing  45 , the input terminal  361   a  presses the output terminal  361   b  provided in the side wall  45   b,  and thus the light-emitting unit  41  is retained within the light-emitting unit  41 . In this way, the light-emitting unit  41  and the housing  45  are removably fixed by utilization of the elastic force of the input terminal  361   a.    
     Here, the side wall  45   b  rising from the bottom surface  45   a  of the housing  45  is provided in a lattice shape, the interior of the housing  45  is divided into a plurality of spaces and thus it is possible to hold the light-emitting unit  41  in each of the divided spaces. 
       FIG. 7  is a partially enlarged schematic cross-sectional view of the planar light-emitting illumination device of  FIG. 6 ; the input terminal  361   a  is formed with a metal piece having conductivity, and one end of the metal piece is coupled to the anode wiring (not shown) or the cathode wiring (not shown) extending to the side surface of the mounting substrate  41   b.  The other end of the metal piece extends out in a direction away from the side surface of the mounting substrate  41   b,  and a spring pressure is generated in the direction away from the side surface of the mounting substrate  41   b.  The spring terminal is not limited to the case where the spring terminal is provided in the input terminal  361   a;  the spring terminal may be provided in the output terminal  361   b.  In this case, the output terminal  361   b  presses the opposite side surface of the light-emitting unit  41 , and sandwiches and retains the light-emitting unit  41 . A plurality of spring terminals are further provided, and thus it is possible to stably retain the light-emitting units  41  within the housing  45 . 
     Moreover, as shown in  FIG. 8 , a magnet having conductivity may be used as the connection unit that connects the housing  45  and the light-emitting unit  41 .  FIG. 9  is a schematic plan view showing the back surface side of the light-emitting unit  41 ; a band-shaped input terminal  461   a  formed with the conductive magnet is provided in two places of the back surface of the mounting substrate  41   b.  One input terminal  461   a  is electrically connected to the anode wiring  31  a connecting to the LED  41   a,  and the other input terminal  461   a  is electrically connected to the anode wiring  32   a  connecting to the LED  41   a.  In the inner side of the housing  45 , an output terminal  461   b  that can absorb the input terminal  461   a  and that has conductivity is provided in two places. 
     When the input terminal  461   a  absorbs the output terminal  461   b,  the light-emitting unit  41  is fixed within the housing  45  by utilization of magnetization of the magnet. The output terminal  461   b  is electrically connected to the anode wiring or the cathode wiring on the side of the housing  45 , and, when the input terminal  461   a  absorbs the output terminal  461   b,  the anode wiring on the side of the output terminal  461   b  becomes electrically conductive to the anode wiring on the side of the input terminal  461   a,  and the cathode wiring on the side of the output terminal  461   b  becomes electrically conductive to the cathode wiring on the side of the input terminal  461   a.    
     Although in the above description, the mounting substrates  41   b  have the same shape (only a square), the present invention is not limited to this configuration. For example, square mounting substrates  41   b  and rectangular mounting substrate  41   b  are combined (a plurality of mounting substrates  41   b  having a plurality of types of shapes are collected), and thus the aggregation of the light-emitting units  41  may be formed within the housing  45 . Moreover, mounting substrates  41   b  having another shape such as a circular shape or a triangular shape are collected, and thus the aggregation of the light-emitting units  41  may be formed. 
     Although in the above description, a plurality of LEDs  41   a  are mounted on the mounting substrate  41   b,  the present invention is not limited to this configuration. For example, a plurality of light-emitting units  41  each of which has one LED  41   a  mounted on one mounting substrate  41   b  may be arranged within the housing  45 . In this case, since a faulty LED  41   a  can be replaced by replacement of the light-emitting unit  41 , it is easy to perform an operation of replacing the LED  41   a.  By the arrangement of the connection units provided within the housing  45 , it is possible to change, as necessary, the density (distribution density) of the LEDs  41   a  in the planar light-emitting illumination device  49 . Hence, the LEDs  41   a  are arranged densely, and thus it is possible to provide bright regions as compared with the other portions over the entire light emission surface  50  of the planar light-emitting illumination device  49 . A light collection member such as a lens is provided on the light emission surface of each LED  41   a,  and thus it is possible to increase the brightness of each LED  41   a.    
     The light emission color of the LED  41   a  is not particularly limited. For example, all LEDs  41   a  mounted on the mounting substrate  41   b  are designed to have a single color, and thus it is possible to provide a red light-emitting unit  41 , a blue light-emitting unit  41  or a green light-emitting unit  41 . Here, these light-emitting units  41   a  are mixed and arranged within the housing  45 , and thus it is also possible to form the planar light-emitting illumination device  49  that applies white light by mixing the colors. Moreover, red LEDs  41   a,  blue LEDs  41   a  and green LEDs  41   a  are mixed and mounted on the mounting substrate  41   b,  and thus it is possible to form a white light-emitting unit  41  that applies white light by mixing the colors. In this case, the white light-emitting units  41  are arranged within the housing  45 , and thus it is possible to form the planar light-emitting illumination device  49  that applies white light. Light-emitting units  41  that apply light of another color (single color light or mixed color light) may be combined. 
     INDUSTRIAL APPLICABILITY 
     In the planar light-emitting illumination device of the present invention, a plurality of light-emitting units are provided within the housing, the light-emitting units and the housing are removably fixed through the connection units, and thus it is possible to easily replace the light-emitting semiconductor element used in the light-emitting unit and to continue to use the housing itself by replacement of the light-emitting unit. A light-emitting unit that has a size corresponding to the housing is produced, and thus it is possible to individually sell the light-emitting unit as a replacement unit of the planar light-emitting illumination device. 
     LIST OF REFERENCE SYMBOLS 
       31  anode (positive pole) 
       31   a  anode wiring 
       32  cathode (negative pole) 
       32   a  cathode wiring 
       41  light-emitting unit 
       41   a  LED 
       41   b  mounting substrate 
       43  light diffusion cover 
       45  housing 
       45   a  bottom surface 
       45   b  side wall 
       49  planar light-emitting illumination device 
       50  light emission surface 
       61  connection unit 
       61   a  plug 
       61   b  outlet 
       61   c  insertion hole 
       71  control driver