Abstract:
A light fixture consists of one or more light emitting diode (LED) packaging systems within a housing. Each LED packaging system includes one or more LED light sources that simultaneously shines onto opposing reflecting surfaces, then shines forward through encapsulation material. The housing consists of a cluster of prewired sockets with an outer reflective surface. Electrical wiring runs from the rear of the first socket and then to an adjacent socket in a daisy chain fashion. Each socket includes connectors configured to provide each LED packaging system with a source of electricity. The housing has diffusers that adjust the light to an evenly distributed appearance.

Description:
This application claims the benefit of Provisional application No. 60/343,506 filed on Dec. 21, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The disclosed embodiments of the invention relate generally to lighting fixtures used for illumination purposes, and more particularly, to lighting fixtures used in buildings for the purpose of general illumination and accent illumination. 
     2. Description of the Related Art 
     General illumination in buildings is primarily from lighting fixtures. These lighting fixtures use either fluorescent, incandescent or a HID lighting source. 
     When a lighting source lamp burns-out, it must be replaced. Typically, a fluorescent lamp will need to be replaced every 15,000 hours, an incandescent lamp every 2000 hours, and an HID lamp every 20,000 hours. Associated ballast replacement occurs about every five years. The cost to conduct such maintenance and replacement can be expensive as well as disruptive to the occupants. 
     Lighting fixtures also deteriorate over time. Fixtures, and particularly metal fixtures, can be scraped or bent during maintenance or when an object strikes the fixture. This deterioration over time reduces fixture performance and fixture aesthetics. 
     In addition to maintenance, the cost of operating a fixture is tied directly to its energy use. Many municipalities also have restrictions on the amount of energy that can be allocated to general and accent illumination by lighting fixtures. 
     In present designs, LEDs are forward facing and the viewer can thus see the individual LED light sources. Typically these light sources appear as dots, which are not visually appealing and tend to not meet the criteria for illumination appearance desired by most users. 
     Thus it would be a great benefit to have a fixture that is virtually maintenance free, is resistant to deterioration of performance over its life span, has reduced power consumption, and has a softer appearance. 
     BRIEF SUMMARY OF THE INVENTION 
     An embodiment of the invention provides a lighting device having a reflector with a generally parabolic shape in cross section, a light emitting diode (LED) mounted on an inner surface of the reflector and at a center thereof, and a diffuser, suspended a distance from the center of the reflector and configured to block direct passage of light emitted from the diode. The diode may be one of a plurality of light emitting diodes mounted on the reflector and arranged in a regular configuration. The parabolic shape of the reflector may be formed by a plurality of planar facets co-positioned to provide a generally parabolic shape. 
     According to an embodiment of the invention, the reflector is circular in plan view. 
     According to another embodiment, the reflector has an elongated shape, in plan view, wherein the plurality of diodes are distributed along the length thereof, and wherein the diffuser is shaped and configured to block direct passage of light from each of the plurality of diodes. 
     According to an embodiment of the invention, the reflector, the diode or diodes, and the diffuser are encapsulated in a lighting unit formed from a transparent medium to form an LED packaging system. 
     According to one embodiment of the invention, a lighting fixture is provided, having a socket configured to receive an encapsulated lighting unit, and to provide a source of electricity thereto. The lighting fixture may include a plurality of sockets, each configured to receive a similar lighting unit. 
     One embodiment of the invention provides a method of manufacture of a device as provided by other embodiments of the invention, while another embodiment provides a method of operation of the device. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
       Embodiments of the invention will now be described with reference to the accompanying drawings, wherein: 
         FIG. 1  is an end view of the LED packaging system formed in accordance with the present invention; 
         FIG. 2  is an end view of an LED socket; 
         FIG. 3  is an elevation section schematic of the housing unit with the sockets and a typical LED packaging system assembled; 
         FIG. 4  is an isometric view of an embodiment of the invention; 
         FIG. 5  is an isometric view of an alternative embodiment of the invention; 
         FIGS. 6A-6D  are cross sections of various diffusion treatments, according to the invention; and 
         FIGS. 7 and 8  illustrate alternate embodiments of the invention;. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     An LED light fixture  10  is shown in  FIG. 3  that includes multiple LED packaging systems  12  (shown more clearly in  FIG. 1 ) resting within multiple sockets  14  (shown in detail in  FIG. 2 ) that are all enclosed within a housing  16 . 
     As shown in  FIG. 1 , the LED packaging system  12  consists of a parabolic-shaped reflector  18  that is curved and has a cluster of LEDs  28  mounted within the reflector  18  in the center of the parabola. At a focal point of the reflector  18  is a diffuser  20  configured to have a curved shape with an inner, concave, face  22  facing an inner, concave, face  24  of the reflector  18 . The diffuser  20  is shaped and configured to prevent light from the LED&#39;s from exiting the reflector  18  without reflecting from at least one surface of the reflector  18 . Outer rims  21  of the diffuser  20  extend to a point that light from the LED&#39;s passing the rims  21  must strike the face  24  of the reflector  18 . The inner face  22  of the diffuser  20  may be polished to reflect light back to the parabolic reflector  18 , or it may be configured to diffuse light. For example the diffusion may be in the form of faceting or frosting of the inner face  22 , or the inner face  22  may have a non-reflective coating, such as flat black, for example, to absorb light striking thereon. The diffuser  20  is fixed in place by supports  23  in a conventional manner. Wiring  26  from the LED cluster  28  is routed via a hole  30  through the back  32  of the reflector  18  to electrical terminals  34 . 
     According to one embodiment of the invention, the reflector  18  is round in plan view as shown in FIG.  4 . According to another embodiment, the reflector is elongated, as shown in FIG.  5 . 
     The entire assembly is encapsulated with a transparent encapsulate  36 , such as transparent polymer, forming a single lighting unit or LED packaging system  12 . The electrical terminals  34  are affixed to a back face  15  of the encapsulate  36 . 
     Light from the LED cluster  28  simultaneously shines forward and backward onto the reflector  18  and diffuser  20 , then propagates forward through the front face  37  of the encapsulate  36  with a softened appearance. 
     The front face  37  of the encapsulate  36  may have a surface configured to further diffuse light as it passes therethrough. For example,  FIGS. 6A-6D  illustrate various possible surface treatments.  FIG. 6A  illustrates a faceted surface,  FIG. 6B  illustrates a pebbled surface,  FIG. 6C  illustrates a dimpled surface, and  FIG. 6D  illustrates a randomly variegated surface. Other types of surface treatments will be obvious to one of ordinary skill in the art, and are within the scope of the invention. 
     An end face  19  of the encapsulate  36  may be opaque to prevent light from the LED&#39;s  28  from passing, undiffused, from the system  12 . An inner surface of the end face  19  may be non-reflective, or have a reflective and diffusive treatment similar to those described with reference to the diffuser  20 . Alternatively, the end face may be transparent to permit visual inspection of the system  12 . In such a case, external means may be employed to block undiffused light from escaping the device. 
       FIGS. 1 and 5  show the LED packaging system  12  having a pair of flanges  13  adjacent to a back face  15  and configured to engage locking tabs  42  of a socket  14  (shown in FIG.  2 ). 
       FIG. 7  illustrates an alternative embodiment of the reflector  18 , in which the parabolic shape is formed by a series of planar sections or inner facets  21  and outer facets  25 . According to one embodiment the inner facets  21  have a width F that is equal, about ⅜″, while the outer facets  25  have a width of 1¼″. Alternatively, the facets  21 ,  25  may have other dimensions or may vary in size. The width W of the reflector  18  may be 5½″ and the depth D may be 2½″. According to one embodiment, the diffuser  20  is 2½″ wide by ¾″ deep, and is 1″ from the LED&#39;s. 
       FIG. 8  illustrates an alternative embodiment in which the LED&#39;s  28  are located in a recess  29  behind the parabolic reflector  18 , such that light from the LED&#39;s  28  passes through an opening  31  in the reflector  18  to be reflected by the diffuser  20  and inner face  24  of the reflector  18 . 
     Referring to  FIG. 2 , a socket  14  is shown therein to consist of two connector assemblies  38  mounted in a socket housing  40 . Locking tabs  42  are shown that project inward from the side walls  44 . The locking tabs  42  engage the flanges  13  (shown in  FIG. 1 ) of the encapsulated LED light sources, in this case the LED packaging systems  12 . The connector assembly  38  includes a terminal  46  inserted in a coil spring  48  that is secured in the connector assembly  38  via a lock washer  50 . The purpose of the socket  14  is to hold the LED packaging systems  12  and to transfer electricity via the terminals  46  from an electricity source to the LED packaging system  12 . In addition, the socket  14  allows the LED packaging system  12  to be easily replaced, if necessary. 
     Referring next to  FIG. 3 , the LED light fixture  10  is shown, consisting of multiple sockets  14  wired in a parallel daisy chain manner with wiring  52 . The wiring  52  is connected to the terminals  46  with combination metallic plugs and a strain relief (not shown). The parallel daisy chain wiring  52  is connected to an electrical socket  51 , which in turn is rigidly attached to the housing  16 . The source of electricity is connected to the electrical socket  50  via an electrical plug  54 . The housing  16  is an envelope that consists of a diffuser  66  mounted at the base  68 . On both sides of the fixture  10  there is a reflective surface  64  to help direct light from the LED light sources  28  down and out of the LED light fixture  10 . 
     In the event that the end faces  19  (shown in  FIG. 5 ) of the individual systems  12  are not opaque, the light fixture  10  is provided with an end wall configured to block passage of undiffused light. 
     While the invention has been described in the context of a light fixture  10  having four aligned LED packaging systems  12 , it is to be understood that a preferred embodiment of the invention will have a two-by-four arrangement of LED packaging systems  12 . The packaging systems  12  can also be configured to be used as a single down light with one or more LED light sources encapsulated in the LED packaging system  12 . 
     Advantages of the LED light fixture will be apparent to those skilled in the art. For example, while fluorescent lighting may be expected to outlast incandescent lighting by a factor of seven or eight, LED&#39;s typically outlast fluorescent lights by a factor of seven or more, and incandescents by a factor of fifty or more. Additionally, with the development of high output LED&#39;s, the lumens/watt ratio of LED&#39;s exceeds that of fluorescent lamps by a factor of between five and twenty five, and incandescent lamps by a factor of between fifteen and seventy five. Thus, not only do LED&#39;s conserve energy directly by using less power to produce an equal amount of light, they also conserve energy indirectly, inasmuch as a large part of the energy expenditure of modern offices is used to cool the air heated by lighting, not to mention the possible impact on conservation of natural resources. Additionally, because LED systems have a much longer service life, maintenance costs are also reduced. 
     By encapsulating the reflectors and the LED&#39;s in a transparent medium, the reflectors are protected from damage due to handling or other contact, which in turn makes possible the use of very thin or fragile materials in the manufacturing process, since the reflectors will not need to withstand any abuse. This reduces the material cost of the manufacturing. Additionally, the reflector diffuser and LED&#39;s can be optimally aligned prior to encapsulation, without fear that the alignment might be compromised by rough handling. Thus, the light output of the fixture can be maximized while ensuring that the harsh light of the LED&#39;s is properly buffered. 
     While a preferred embodiment of the invention has been illustrated and described, it is to be understood that other changes may be made without departing from the spirit and scope of the invention. For example, while a transparent polymer may be used as the encapsulate, other similar materials can be used or materials having similar properties. A transparent epoxy can also be used as the encapsulate. In addition, the main parabolic-shaped reflector  18 , shown in cross-section in  FIG. 3 , may have an elongate shape with open ends. To prevent the escape of light from the open ends of the main reflective surface  18 , the encapsulate adjacent the open ends can be coated with a reflective material that is readily commercially available. 
     All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, including but not limited to [insert list], are incorporated herein by reference, in their entirety. 
     From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.