Abstract:
A light emitting diode illuminator includes a reflecting shell ( 120 ), a light emitting diode light source ( 140 ) and a transparent cover ( 160 ). The reflecting shell includes a plurality of sequentially connected hollow tapered bodies ( 122, 124 ) having different taper angles. The tapered bodies cooperatively form a receiving space ( 123 ). The light source is installed at an end of the receiving space. The transparent cover is disposed at an opposite end of the reflecting shell away from to the light source and configured for directing light emitted from the light source out from the light emitting diode illuminator.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates generally to an illuminator, and more particularly to an illuminator incorporating a light emitting diode (LED) as a light source. 
         [0003]    2. Description of Related Art 
         [0004]    In recent years, light emitting diodes (LEDs) have become highly efficient light sources and are used widely in such fields as automotive, displays, and traffic control. 
         [0005]    Light generated by LEDs have the advantage in that it can be directed or aimed by using some kind of reflectors. However, because a light field of the LED is usually concentrated illuminating devices using LEDs cannot meet the needs of illuminating a relatively large area. Further, in some cases, such as the street lamp, a long and narrow light field is desired but not easily obtained with present methods. Therefore, there is a need in the art for an LED illuminator, which overcomes the above-mentioned problems. 
       SUMMARY 
       [0006]    In accordance with an embodiment, a light emitting diode (LED) illuminator includes a reflecting shell, at least one LED, and a transparent cover. The reflecting shell includes a plurality of sequentially connected hollow tapered bodies having different taper angles. The hollow tapered bodies cooperatively form a receiving space. The LED is installed at an end of the receiving space. The transparent cover is disposed at an opposite end of the reflecting shell away from the LED and configured for directing light emitted from the LED out from the LED illuminator. 
         [0007]    Other advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with attached drawings, in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present invention is described in greater detail hereinafter, by way of example only, through description of a preferred embodiment thereof and with reference to the accompanying drawing in which: 
           [0009]      FIG. 1  is an exploded, isometric view of an LED illuminator in accordance with a first embodiment of the present invention; 
           [0010]      FIG. 2  is an assembled, cross-sectional view of the LED illuminator of  FIG. 1 ; 
           [0011]      FIG. 3  is an enlarged view of a reflecting shell of the LED illuminator of  FIG. 2 ; 
           [0012]      FIG. 4  is a simulated view of a light field of the LED illuminator of  FIG. 1 ; 
           [0013]      FIG. 5  is an isometric view of a reflecting shell according to a second embodiment of the present invention; 
           [0014]      FIG. 6  is a cross-sectional view of the reflecting shell of  FIG. 5  taken along line VI-VI; 
           [0015]      FIG. 7  shows a simulated view of the light field of the LED illuminator incorporating the reflecting shell of  FIG. 5 ; 
           [0016]      FIG. 8  shows an isometric view of a reflecting shell according to a third embodiment of the present invention; 
           [0017]      FIG. 9  is a cross-sectional view of the reflecting shell of  FIG. 8  taken along line IX-IX; 
           [0018]      FIG. 10  shows a simulated view of the light field of the LED illuminator incorporating the reflecting shell of  FIG. 9 ; 
           [0019]      FIG. 11  shows an isometric, exploded view of a fourth embodiment of the LED illuminator; 
           [0020]      FIG. 12  is an assembled, cross-sectional view of the LED illuminator of  FIG. 11 ; and 
           [0021]      FIG. 13  shows a simulated view of the light field of the LED illuminator of  FIG. 11 . 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0022]    The detailed explanation of a light emitting diode (LED) illuminator  100  according to the present invention will now be made with reference to the drawing attached hereto. Referring to  FIGS. 1-3 , the LED illuminator  100  includes a light source  140 , a reflecting shell  120 , and a transparent cover  160 . 
         [0023]    The reflecting shell  120  includes an upper body  122  and a lower body  124  extending from the upper body  122 . The upper and lower bodies  122 ,  124  are hollow, and thus the two bodies  122 ,  124  cooperatively define a receiving space  123  therein. Particularly referring to  FIG. 3 , the upper and lower bodies  122 ,  124  are similar to each other, and each body  122 ,  124  has a truncated cone shape. Inner surfaces  1222 ,  1242  and outer surfaces  1224 ,  1244  of each body  122 ,  124  are respectively parallel. The upper body  122  is smaller than the lower body  124  with the large end of its truncated cone shape matching in size with and connected to the small end of the truncated cone shape of the lower body  124 . The difference between the two bodies  122 ,  124  of the reflecting shell  120  is that a taper angle α 1  of the upper body  122  is smaller than a taper angle β 1  of the lower body  124 . The taper angle α 1 , β 1  of each body  122 ,  124  is the angle defined between the axis and the generatrix thereof. As the taper angle α 1  of the upper body  122  is smaller than that of the lower body  124 , an inner angle γ 1  formed by the inner surfaces  1222 ,  1242  is greater than 180 degrees. 
         [0024]    The light source  140  is installed in the receiving space  123 . The light source  140  includes a column-shaped base  142  and a plurality of LED arrays  144  arranged around the base  142 . Each array  144  includes a number of LEDs  1442  being linearly arranged, and thus achieving a long strip-like shape. In this embodiment, each array  144  has six LEDs  1442 . The arrays  144  are arranged along a circumferential direction thereof being evenly spaced from each other. A diameter of the base  142  of the light source  140  is approximately the same as the inner diameter of the upper body  122 . In assembly of the LED illuminator  100 , a top end of the base  142  of the light source  140  is assembled in the top end of the upper body  122  thus sealing the top end of the reflecting shell  120 . A power source can be connected to the base  142  to apply current to the LEDs  1442 . 
         [0025]    The transparent cover  160  is connected to a bottom end of the lower body  124  of the reflecting shell  120 . Thus the bottom of the reflecting shell  120  is sealed by the cover  160  to avoid dust or vapor getting into the reflecting shell  120 . The cover  160  can be selected from a group consisting of spherical lens, aspherical lens, micro-lens array, micro-prism array, lenticular array, or Fresnel lens, which can adjust the light field of the LEDs  1442 . The cover  160  is usually made of glass or optically transmissive plastic. In this embodiment, the cover  160  is curved with convex side facing away from the LEDs  1442 . Conversely, the cover  160  can be a flat board only for transmission of the light. 
         [0026]    During operation of the LED illuminator  100 , current is applied to the LEDs  1442 , the LEDs  1442  radiate light, which is directed by the reflecting shell  120  out through the transparent cover  160  of the LED illuminator  100 . As shown in  FIG. 4 , the light field of the LED illuminator  100  is approximately circular-shaped. Thus the shape of the light field of the LEDs  1442  is changed and enlarged compared to conventional LED illuminators. Thus the LED illuminator  100  incorporating the sequentially connected hollow tapered bodies  122 ,  124  can change the light field of the LEDs  1442  to a more desirable and useful shape and size. 
         [0027]      FIGS. 5-6  show an alternative embodiment of the reflecting shell  220  of the present invention. Similar to the first embodiment, the reflecting shell  220  includes a tapered upper body  222  and a tapered lower body  224  sequentially connected together. The inner surfaces  2222 ,  2242  of the two bodies  222 ,  224  are approximately conoid. The taper angle α 2 , β 2  of the inner surface  2222 ,  2242  of each body  222 ,  224  is in range of 10˜70 degree. The taper angle α 2  of the inner surface  2222  of the upper body  222  is smaller than that of the inner surface  2242  of the lower body  224 . The inner angle γ 2  formed by the inner surfaces  2222 ,  2224  is larger than 180 degree. The difference between this embodiment and the first embodiment is that the inner surface  2222 ,  2242  of each body  222 ,  224  is concave, and thus the generatrix of the inner surface  2222 ,  2242  of each body  222 ,  224  is curve. It is to be understood that the inner surface  2222 ,  2242  of each body  222 ,  224  can be convex. In addition, the outer surfaces  2224 ,  2244  of the upper and lower bodies  222 ,  224  are pyramid. In this embodiment, the outer surfaces  2224 ,  2244  of the two bodies  222 ,  224  are twelve-pyramids. In other words, the outer surface  2242 ,  2244  of each body  222 ,  224  includes twelve sidewalls being connected end to end. Each sidewall is planar and trapeziform. It is to be understood that the sides of the pyramids are not limited to be twelve, fifth-pyramid, twenty-pyramid are also be suitable.  FIG. 7  shows the simulated view of the light field of the LED illuminator incorporating the reflecting shell  220  which is circular. 
         [0028]    As shown in  FIGS. 8-9 , the reflecting shell  320  according to a third embodiment of the present invention is shown. The reflecting shell  320  includes a plurality of four-pyramid bodies being sequentially connected. Each body forms a convex outer surface and a concave inner surface. Cooperatively the inner surfaces of the bodies form a glazed concave inner surface  3222  of the reflecting shell  320 , and cooperatively the outer surfaces of the bodies form a glazed convex outer surface  3224  of the reflecting shell  320 . The taper angles of the bodies decrease downwardly along the axis of the reflecting shell  320 . As shown in  FIG. 10 , a simulated view of the light field of the LED illuminator is elongated and is approximately elliptic, which is similar to the shape of the street and thus can be used for illuminating the street. 
         [0029]    Referring to  FIGS. 11-12 , a fourth embodiment of the LED illuminator  400  according to the present invention is shown. The LED illuminator  400  includes a light source  140 , a transparent cover  160 , a reflecting shell  120 , and an outer shell  420 . The Light source  140 , the reflecting shell  120  and the transparent cover  160  are substantially the same as the first embodiment. The outer shell  420  is mounted around the reflecting shell  120  with an inner space defined therebetween. The reflecting shell  120  is made of opaque reflecting material or translucent reflecting material. The outer shell  420  includes an upper body and a lower body extending downwardly from the upper body. Each body of the outer shell  420  has a truncated cone shape. The top end of the upper body of the outer shell  420  extends inwardly and thus abuts the outer surface of the upper body of the reflecting shell  120 . Thus the top ends of the shells  120 ,  420  are connected closely. The bottom ends of the lower bodies of the shells  120 ,  420  are approximately at the same level, the transparent cover  160  is connected to the bottom ends of the lower bodies to seal the bottom ends of the shells  120 ,  420 .  FIG. 13  shows the illuminator  400  has a circular-shape light field. 
         [0030]    It can be understood that the above-described embodiment are intended to illustrate rather than limit the invention. Variations may be made to the embodiments and methods without departing from the spirit of the invention. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.