Abstract:
A lighting apparatus comprises: an upper housing having a graduated stepped cylindrical profile, forming an upper portion of the lighting apparatus; a substantially annular heat sink having a round profile around its outer periphery and a hexagonal profile around its inner periphery, and being shaped so as to have an opening at the bottom of the heat sink; a plurality of LEDs located around the inner periphery of the heat sink, the LEDs being oriented so as to emit light in an upward direction at an angle; and a hexagonal reflector situated between the upper housing and the heat sink, the hexagonal reflector having a downwardly reflective lower surface. When the lighting apparatus is assembled and power is applied to the LEDs, light emitted from the LEDs is reflected off of the lower surface of the reflector so as to exit through the opening at the bottom of the heat sink.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/389,496, filed Oct. 4, 2010, which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a lighting apparatus used for lighting. In a preferred embodiment, the lighting apparatus is flat modulus light source having an LED light source that includes one or more LED chips. 
         [0003]    Conventionally, light bulbs for light sources may be compact fluorescent bulbs, or incandescent bulbs. In recent years LEDs have been proposed and used in lighting, for example LEDs with individual collimated lenses. However, such LED lights do not provide for a uniformity of the light coming from the light source and therefore might cause discomfort to the eyes. 
         [0004]    Lighting units that use light reflected from LEDs are known. In particular, Lithonia lighting downlight DOM6 LED 600L 3500K 120HSG provides a downlight in which light is reflected down. However, the Lithonia unit is a large and heavy fixture, with a heat sink at the top of the unit, and is incompatible with standard light fixture standards, such as GX53. Thus, the need exists for a light with a small profile and with light weight, and one that may be used as a light bulb, for example as a replacement bulb with standard light sockets, while at the same time providing uniform light without causing discomfort to the eyes. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    In accordance with one aspect of the present invention, a lighting apparatus comprises: an upper housing having a graduated stepped cylindrical profile, forming an upper portion of the lighting apparatus; a substantially annular heat sink having a round profile around its outer periphery and a hexagonal profile around its inner periphery, and being shaped so as to have an opening at the bottom of the heat sink; a plurality of LEDs located around the inner periphery of the heat sink, the LEDs being oriented so as to emit light in an upward direction at an angle; and a hexagonal reflector situated between the upper housing and the heat sink, the hexagonal reflector having a downwardly reflective lower surface. When the lighting apparatus is assembled and power is applied to the LEDs, light emitted from the LEDs is reflected off of the lower surface of the reflector so as to exit through the opening at the bottom of the heat sink. 
         [0006]    In another aspect, the lighting apparatus further comprises an AC to DC driver that converts power from outside the light source into signals appropriate for driving the LEDs. 
         [0007]    In another aspect, the AC to DC driver is snap fit into an interior portion of the upper housing and includes knobs which protrude from holes in an upper portion of the upper housing, the knobs being configured to mate with a light fixture/socket to provide power to the AC to DC driver. 
         [0008]    In another aspect, the AC to DC driver is snap fit into an interior portion of the upper housing and includes first wires which extend from one or more holes in an upper portion of the upper housing, the first wires being configured to couple with an outside power source to provide power to the AC to DC driver. 
         [0009]    In another aspect, the inner periphery of the heat sink is hexagonal in shape. 
         [0010]    In another aspect, the LEDs are mounted on a flexible PCB that is folded so as to lie on a surface of the inner periphery of the heat sink. 
         [0011]    In another aspect, the LEDs are mounted on circuitry directly printed on a surface of the inner periphery of the heat sink, the circuitry comprising a copper layer on which the LEDs are affixed, the copper layer being coupled to the AC to DC driver. 
         [0012]    In another aspect, the inner periphery is angled. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    The figures are for illustration purposes only and are not necessarily drawn to scale. The invention itself, however, may best be understood by reference to the detailed description which follows when taken in conjunction with the accompanying drawings in which: 
           [0014]      FIG. 1  is a cross-sectional view of a flat module light source in accordance with an embodiment of the present invention; 
           [0015]      FIG. 2  is an exploded parts view of a flat module light source in accordance with an embodiment of the present invention; 
           [0016]      FIG. 3A  is a perspective view of a heat sink portion with LEDs and associated circuitry used in a flat module light source in accordance with an embodiment of the present invention; 
           [0017]      FIG. 3B  is a cross-sectional view of the heat sink portion shown in  FIG. 3A  along the line  3 B; 
           [0018]      FIGS. 4A and 4B  are side cross-sectional views of the flat module light source in accordance with an embodiment of the present invention; 
           [0019]      FIG. 5  is a cross-sectional view of a flat module light source in accordance with another embodiment of the present invention; and 
           [0020]      FIG. 6  is an exploded parts view of a flat module light source in accordance with the embodiment of the present invention shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0021]      FIGS. 1-4B  illustrate a first preferred embodiment of a flat module light source, in accordance with the present invention. As can be seen in the figures, a flat module light source  1  in accordance with an embodiment of the present invention is formed of an upper housing  10 , an AC to DC driver module  11   a  having wings  12  having mounted thereon knobs  13 . A reflective portion  14 , having a reflective upper surface, is provided, as well as a heat sink  16  and a lens cover  18 . 
         [0022]    The upper housing  10  is preferably formed with a graduated cylindrical shape as shown in the figures. Preferably, the driver module  11  is mountable within the housing  10  by snap fit or screwing into the surface of the second largest circumference of the housing. The housing  10  is formed so as to allow the outermost (i.e., largest circumference) portion to snugly fit around the upper edge of the heat sink  16  when assembling the light source  1 . Preferably, the innermost portion of the upper housing is sized so as to allow the light source  1  to be compatible with and fit snugly within a standard light socket/fixture, such as the known GX53 socket/fixture. The upper housing  10  is preferably formed of plastic or other moldable material. 
         [0023]    The reflective portion  14  is preferably hexagonal in shape with a reflective surface on a lower surface thereof. The reflective surface can be provided by making the reflective portion  14  out of a reflective metal, or by the use of reflective paint. The reflective portion  14  rests on and mates with a hexagonal inner ring  22  formed in the heat sink  16 . LEDs  15  are mounted around the inner periphery of the heat sink  16 , on a surface of the inner ring  22 . 
         [0024]    In one preferred embodiment, the LEDs are mounted on a flexible PCB (FPCB)  17  folded in a hexagonal shape and affixed, e.g., by gluing, onto the inner surface  22  of the heat sink  16 . Electrical connection between the driver module  11  and the FPCB is provided by wires  26   a.  While the illustrated embodiment shows a folded FPCB, the invention is not limited to this configuration. For example, small pieces of PCB could be provided, one for each LED, with a wired connection between each PCB to enable power connection. As another example, the LEDs can be mounted on circuitry, such as an insulator and a copper layer, that is directly printed on the inner surface of the heat sink. Such an embodiment will be discussed below with reference to  FIGS. 3A and 3B . 
         [0025]    The bottom of the heat sink  16  includes an annular lower portion  20  that is arched upward toward the center of the heat sink  16 , the inner portion forming an aperture for allowing reflected light from the LEDs to exit the light source  1 . The hexagonal rim forming the inner surface  22  is preferably formed around the inner periphery of the heat sink  16 . 
         [0026]    Preferably, the light source  1  includes a bottom cap or lens cover  18 . The lens cover  18  can be made of plastic or other similar material and may be frosted (i.e., light diffusing) to provide for more scattered light, for the comfort of the eye. The lens cover  18  can also be clear. In any event, in addition to modifying the light, the lens cover protects the light source  1  from dust, dirt and moisture. It is also contemplated that the lens cover  18  can comprise a collimated lens or a plurality of such lenses, to achieve a tighter angle for the light emitted from the light source  1 . 
         [0027]    In the embodiment shown in  FIGS. 1 and 2  the light source supplies power to the LEDs using the AC/DC driver module  11   a . The AC to DC driver module  11   a  preferably has wings  12  having mounted thereon knobs  13 . The knobs  13  are provided to, e.g., to get power when fixed to a lamp socket, for example a GX53 lamp socket, and apply the power to the AC to DC driver module, which converts the incoming power to DC signals that can be used to drive the LEDs. The actual circuitry that forms the AC to DC driver can be of any known type for converting AC power to DC driving signals. The DC signals are then provided to the FPCB  17  via wires  26   a  for driving the LEDs. 
         [0028]    The AC to DC driver module  11   a  having the wings  12  and the knobs  13  would preferably be of a profile compatible with a standard light fixture mounting standard, such as the known GX53 standard, allowing the light source to be mounted into any standard GX53 lamp socket. Thus, the knobs  13  can be configured to be compatible which such a light socket. Of course the present invention is not limited to having a shape compatible with the GX53 lamp socket. Preferably the AC to DC driver module  11   a  is formed so as to allow the AC to DC driver module  11   a  to be snap fit or screwed into the interior of the upper housing  10 . 
         [0029]      FIGS. 3A and 3B  show another method of applying the LEDs to the inner surface  22  of the heat sink  16 . In this embodiment, rather than use the FPCB, the LEDs are attached, for example by solder joints  160 , to circuitry that has been directly printed on the inner surface  22  of the heat sink. The directly printed circuitry has an insulator  170 , and a copper layer  180 . The circuitry receives voltage for driving the LEDs from wires  26   a,  which are coupled to copper layer  180  and are also soldered and connected to the AC to DC driver module  11   a . The wires  26   a  run through the upper housing  10 . The copper layer  180  comprises the circuitry for applying the driving and other voltages to the individual LEDs. For example, the copper layer  180  may have a thickness of about 0.1 mm. The walls of the inner surface of the hexagonal rim  22  are angled upwardly diagonally so that the light from the LEDs goes up at an angle. The upwardly angled light will then be reflected against the reflective portion  14 , and then downwardly out of the bottom of the light source  1 . The types of LEDs used may vary depending on the brightness and heat dissipation, but may include, for example Cree MX6 or Cree XPE LEDs. 
         [0030]    In assembling the light source  1 , hexagonal the reflective portion  14  is placed over the hexagonal rim  22 , to rest atop the rim  22 . This configuration advantageously allows light being emitting upwardly from the LEDs to reflected at a downward angle and out of the bottom of the light source  1 . The upper housing  10  is affixed to the heat sink, for example, by a snap fit. If the lens  18  is used, it also attaches to the bottom of the heat sink, for example by a snap fit. 
         [0031]      FIGS. 4A and 4B  are functional cross sectional views of a light source in accordance with one aspect of the present invention, but without showing details of the circuitry or AC to DC driving circuits discussed above. The arrows in  FIGS. 4A and 4B  illustrate how the light emitted from the LEDs  15  strikes the reflector  14 , and is redirected out of the bottom of the light source  1 . In FIGS.  4 A and  4 B, the path of light from the LEDs  15  is shown by the arrows as reflecting off the reflective surface  14  and then down out of the light source  1 . 
         [0032]    In the embodiment shown in  FIGS. 1 and 2  the light source supplies power to the LEDs using the AC/DC driver module  11   a  having knobs  13  for coupling to outside power supply, such as AC power from the wall or ceiling. Another embodiment is shown in  FIGS. 5 and 6 . In the embodiment shown in  FIGS. 5 and 6 , instead of the light source receiving outside power from knobs in the AC to DC driver module, wires  26  are provided for supplying AC power to an AC to DC driver module  11   b.    
         [0033]    As can be seen from the figures, wires  26  enter a hole in the top of the upper housing  10  and are connected to the AC to DC driver module  11   b . Just as was the case in the embodiment of  FIGS. 1 and 2 , the signals converted by the driver module  11   b  are supplied to the LEDs via wires  26   b,  which connects to the FPCB  17 . The other components of the embodiment shown in  FIGS. 5 and 6  having like reference numerals are identical to those described in  FIGS. 1-4B , and the light source functions in the same manner, for example as shown in  FIGS. 4A and 4B . As was the case with regard to the configuration shown in  FIGS. 1 and 2 , in the configuration shown in  FIGS. 5 and 6 , the LEDs can be attached to the FPCB  17 , or alternatively to individual small pieces of PCB, or with the directly printed circuitry as shown in  FIGS. 3A and 3B . The description of those identical aspects will not be repeated here. 
         [0034]    The use of wires  26  instead of knobs allows flexibility to allow connection to other socket types or wired connections. The wires can be connected to any plugs to suit power sockets for different countries or the wiring can be done directly by electricians to connect to external power. Depending on the driver design and whether AC or DC will be used, there may be 2-3 wires. In the case of 2 wires, the wires would typically be live and neutral. If 3 wires, live, neutral and ground. 
         [0035]    The lens cover  18  in either embodiment is preferably a transparent, frosted or otherwise light diffusing cover that softens the light from the LEDs  15  that has been reflected down. The lens cover  18 , is shaped at its upper edge so as to couple, for example by a snap-fit, to the heat sink  16  The cover  18  is preferably made of transparent polymer such as PC, PMMA, PVC or PU having a high light transmissivity, or other plastic or glass, or any other material that can pass light. 
         [0036]    Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations may be substituted for the specific embodiments shown and described without departing from the scope of the present invention. This provisional application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, it is intended that this invention be limited only by the claims and the equivalents thereof.