Abstract:
A reflector configured for reflecting light emitted from a light emitting diode (LED) toward a desired area is provided. The reflector defines a groove therein for accommodating the LED. Light emitted from the LED is reflected by an inner surface of the reflector toward a desired area located below the reflector, wherein the light reflected out of the reflector travels along a direction opposite to the main emitting direction of the LED. An LED illumination device incorporating the reflector is also provided.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to Chinese Patent Application No. 
         [0002]    201410442548.1 filed on Sep. 02, 2014, the contents of which are incorporated by reference herein. 
       FIELD 
       [0003]    The subject matter herein generally relates to a reflector, especially also relates to a light emitting diode illumination device having the reflector. 
       BACKGROUND 
       [0004]    Light emitting diodes (LEDs) have been used widely in the illumination field because of the high efficiency, energy saving, and long life cycle thereof. Light emitted from the LED is projected around an axis of the LED. LED devices often are implemented in arrays of multiple LEDs in a single fixture. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Implementations of the present technology will now be described, by way of example only, with reference to the attached figures. 
           [0006]      FIG. 1  is a cross sectional view of an LED illumination device with a table of a first embodiment of the present disclosure. 
           [0007]      FIG. 2  is a diagrammatic view of the LED illumination device projecting on the table of  FIG. 1 . 
           [0008]      FIG. 3  is a cross sectional view of the reflector of  FIG. 1  showed from a second embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0009]    It will be appreciated that for simplicity and clarity of illustration, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. The description is not to be considered as limiting the scope of the embodiments described herein. 
         [0010]    Several definitions that apply throughout this disclosure will now be presented. The term “comprising” means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in a so-described combination, group, series and the like. 
         [0011]    Referring to  FIG. 1 , a light emitting diode (LED) illumination device  1  includes a plurality of LEDs  20  and two reflectors  10  incorporating with the LEDs  20 . The LED illumination device  1  emits light to a table  2  located below the LED illumination device  1 . While a table  2  is provided herein, the present disclosure contemplates replacing the table  2  with any surface that is substantially flat and satisfies the other conditions of the table present herein. The two reflectors  10  are located at opposite side of a top of the table  2  and configured symmetrically about an imaginary surface perpendicularly to the table  2 . 
         [0012]    Each reflector  10  defines a groove  15  therein. The LEDs  20  are received in the groove  15 . Light emitted from the LED  20  is reflected by an inner surface of the reflector  10  and to be projected towards the table  2 . A projecting direction of the light is contrary with a direction of the light emitted from the LEDs  20 . 
         [0013]    A cross section of the reflector  10  is L-shaped. Each reflector  10  includes a first reflecting plate  11 , a second reflecting plate  12  and a third reflecting plate  13 . The third reflecting plate  13  is configured above and relatively to the first reflecting plate  11 . The second reflecting plate  12  connects the first reflecting plate  11  and the third reflecting plate  13 . Specifically, the first reflecting plate  11 , the second reflecting plate  12  and the third reflecting plate  13  cooperatively defines the groove  15 . A side of the reflector  10  has an opening  14  relative to the second reflecting plate  12  such that the groove  15  directly contacts with external by the opening  14 . 
         [0014]    In at least one embodiment, a top surface of the first reflecting plate  11  and the third reflecting plate  13  are configured parallelly to a top surface  201  of the table  2 , and both sides surface of the second reflecting plate  12  configured vertically with the top surface  201  of the table  2 . A length of the third reflecting plate  13  is more than that of the first reflector plate  11 . Left ends of first reflecting plate  11  and the third reflecting plate  13  are coplanar. The second reflecting plate  12  connects the left ends of the first reflecting plate  11  and the third reflecting plate  13 . A right end of the third reflecting plate  13  is beyond a right end of the first reflecting plate  11 . The reflector  10  is made of thermal conductive material, such as aluminum, or cooper. 
         [0015]    The LEDs  20  are mounted on the top surface the first reflecting plate  11  and spaced from the third reflecting plate  13 . Light emitted From the LEDs  20  is reflected by the first reflecting plate  11  and the third reflecting plate  13  to exit through the opening  14 . In this embodiment, the LEDs  20  includes a plurality of white LEDs arranged in series near the opening  14 . In other embodiment, the LEDs  20  includes a red LED, a green LED and a blue LED to mix to be white light in the groove  15 . 
         [0016]    Also referring to  FIG. 2 , the table  2  has a length of L 4 , and a width of L 5 . A width of the reflector  10  is equal to that of the table  2 . An area of the reflector  10  projected to the top surface  201  of the table  2  has a width of L 3 . In one example, the length L 4  is 120 cm, and the width L 5  is 60 cm. The two reflectors  10  are located at two ends along the long direction thereof and above the table  2 . A distance between the reflector  10  and the table  2  is a height H 1 . The height H 1  can be 50 cm. 
         [0017]    Because the reflector  10  has the width equal to the table  2 , the length of the reflector  10  is not changed. Only changes the length of the third reflecting plate  13  can change the area of the LED illumination device  1  projected to the table  2  to adjust the light intensity provided by the LED illumination device  1  on the table  2 . Generally, the light intensity uniformity is a ratio between the lowest light intensity and the average light intensity, and has nothing with a shape of the LEDs  20  and the reflector  10 . So the light intensity uniformity of the LED illumination device  1  projected to the table  2  can be adjusted by changing the length of the third reflecting plate  13 . 
         [0018]    In one embodiment, a ratio between an area of the third reflecting plate  13  projected to the table  2  and the top surface  201  of the table is defined X. The X and the light intensity uniformity have relations as following chart: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 X 
                 Light intensity uniformity 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 0.2 
                 0.648 
               
               
                   
                 0.15 
                 0.67 
               
               
                   
                 0.1 
                 0.667 
               
               
                   
                 0.05 
                 0.63 
               
               
                   
                 0.0167 
                 0.679 
               
               
                   
                 0.0142 
                 0.63 
               
               
                   
                 0.0136 
                 0.604 
               
               
                   
                 0.0133 
                 0.587 
               
               
                   
                 0.0116 
                 0.466 
               
               
                   
                   
               
             
          
         
       
     
         [0019]    As illustrated in the chart, while the X&gt;0.0136, the light intensity uniformity is less than 0.6. However , in order to have a great light effect, the light intensity uniformity is greater than 0.6. Therefore, a relationship can be construed as 0.0136≦x≦1. 
         [0020]    Further referring to  FIG. 3 , a reflector  10   a  of the LED illumination device  1  of a second embodiment is provided. The reflector  10   a  differing from the reflector  10  is that the third reflecting plate  13  has arc-shaped. A cross sectional of the third reflecting plate  13  is arc. 
         [0021]    A length of the first reflecting plate  11  projected to the table  2  is L 1 . The length of the second reflecting plate  12  is L 2 . A length of the third reflecting plate  13  projected to the table  2  is L 3 . A projection of the first reflecting plate  11  along a direction paralleled with the top surface  201  of the table  2  defines a vector {right arrow over (OP 2 )}. The second reflecting plate  12  along an extending direction thereof defines a vector {right arrow over (OP)}. The projection of the third reflecting plate  13  along a direction paralleled with the top surface  201  of the table  2  defines a vector {right arrow over (PP 1 )}. The third reflecting plate  13  along an extending direction thereof defines a vector {right arrow over (PP 3 )}. The {right arrow over (PP 3  )} satisfies following relations: 
         [0000]    
       
         
           
             
               
                 PP 
                 3 
               
               → 
             
             = 
             
               
                 
                   [ 
                   
                     
                       2 
                        
                       
                           
                       
                        
                       
                         AV 
                          
                         
                           ( 
                           
                             1 
                             - 
                             V 
                           
                           ) 
                         
                       
                     
                     
                       1 
                       + 
                       
                         2 
                          
                         
                           ( 
                           
                             A 
                             - 
                             1 
                           
                           ) 
                         
                          
                         V 
                       
                       + 
                       
                         2 
                          
                         
                           ( 
                           
                             1 
                             - 
                             A 
                           
                           ) 
                         
                          
                         
                           V 
                           2 
                         
                       
                     
                   
                   ] 
                 
                  
                 
                   
                     PP 
                     1 
                   
                   → 
                 
               
               = 
               
                 
                   [ 
                   
                     
                       V 
                       2 
                     
                     
                       1 
                       + 
                       
                         2 
                          
                         
                           ( 
                           
                             A 
                             - 
                             1 
                           
                           ) 
                         
                          
                         V 
                       
                       + 
                       
                         2 
                          
                         
                           ( 
                           
                             1 
                             - 
                             A 
                           
                           ) 
                         
                          
                         
                           V 
                           2 
                         
                       
                     
                   
                   ] 
                 
                  
                 
                   
                     PP 
                     2 
                   
                   → 
                 
               
             
           
         
       
     
         [0000]    The A and the V are constant, and 0≦A≦1000, 0≦V≦1. While the A is constant, the V is changed from 0 to 1 to form the trajectory of the third reflecting plate  13 . An angle is defined between the {right arrow over (PP 1  )} and the {right arrow over (PP 2 )}. The {right arrow over (PP 3  )} is located in the angle. While the length of L 1  is equal to the length of L 2 , the angle is 45°. 
         [0022]    While the A is increased, the {right arrow over (PP 3  )} gradually moves towards the {right arrow over (PP 1 )}; while the A is reduced, the {right arrow over (PP 3  )} gradually moves towards the {right arrow over (PP 1 )}. For example, while the A=0, the PP 3  overlaps together with the {right arrow over (PP 1 )}. 
         [0023]    While the X=0.1, the relation between A and the light intensity uniformity illustrated as following chart: 
         [0000]    
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                 A 
                 Light intensity uniformity 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 0.15 
                 0.679 
               
               
                   
                 0.13 
                 0.683 
               
               
                   
                 0.12 
                 0.717 
               
               
                   
                 0.1 
                 0.73 
               
               
                   
                 0.05 
                 0.738 
               
               
                   
                 0.01 
                 0.72 
               
               
                   
                 0 
                 0.73 
               
               
                   
                   
               
             
          
         
       
     
         [0024]    As illustrated in the chart, while X=0.1, the scope of A is: 0≦A≦0.15, and the light intensity uniformity is more than 0.667. 
         [0025]    In the present disclosure, the light emitted from the LEDs  20  is reflected by the reflector  10  or reflector  10   a  to be projected to the table  2 . So adjusting the light intensity uniformity at the table  2  is by changing the area of the reflector  10  and the reflector  10   a  projected to the table  2 , or by changing the shaped of the reflector  10  or the reflector  10   a . So the light reflected by the reflector  10  or the reflector  10   a  to be projected to the table  2  has uniform light intensity. 
         [0026]    The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of a reflector and LED illumination device having the same. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes can be made in the detail, including in matters of shape, size and arrangement of the parts within the principles of the present disclosure up to, and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above can be modified within the scope of the claims.