Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is related to and claims priority from earlier filed provisional patent application No. 60/338,893, filed Dec. 10, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a new assembly for packaging a high intensity LED lamp for further incorporation into a lighting assembly. More specifically, this invention relates to an assembly for housing a high intensity LED lamp that provides integral electrical connectivity, integral heat dissipation and an integral reflector device in a compact and integrated package for further incorporation into a lighting device and more specifically for use in a flashlight. 
     Currently, several manufacturers are producing high brightness light emitting diode (LED) packages in a variety of forms. These high brightness packages differ from conventional LED lamps in that they use emitter chips of much greater size, which accordingly have much higher power consumption requirements. In general, these packages were originally produced for use as direct substitutes for standard LED lamps. However, due to their unique shape, size and power consumption requirements they present manufacturing difficulties that were originally unanticipated by the LED manufacturers. One example of a high brightness LED of this type is the Luxeon™ Emitter Assembly LED (Luxeon is a trademark of Lumileds Lighting, LLC). The Luxeon LED uses an emitter chip that is four times greater in size than the emitter chip used in standard LED lamps. While this LED has the desirable characteristic of producing a much greater light output than the standard LED, it also generates a great deal more heat than the standard LED. If this heat is not effectively dissipated, it may cause damage to the emitter chip and the circuitry required to drive the LED. 
     Often, to overcome the buildup of heat within the LED, a manufacturer will incorporate a heat dissipation pathway within the LED package itself. The Luxeon LED, for example, incorporates a metallic contact pad into the back of the LED package to transfer the heat out through the back of the LED. In practice, it is desirable that this contact pad in the LED package be placed into contact with further heat dissipation surfaces to effectively cool the LED package. In the prior art attempts to incorporate these packages into further assemblies, the manufacturers that used the Luxeon LED have attempted to incorporate them onto circuit boards that include heat transfer plates adjacent to the LED mounting location to maintain the cooling transfer pathway from the LED. While these assemblies are effective in properly cooling the LED package, they are generally bulky and difficult to incorporate into miniature flashlight devices. Further, since the circuit boards that have these heat transfer plates include a great deal of heat sink material, making effective solder connections to the boards is difficult without applying a large amount of heat. The Luxeon LED has also been directly mounted into plastic flashlights with no additional heat sinking. Ultimately however, these assemblies malfunction due to overheating of the emitter chip, since the heat generated cannot be dissipated. 
     There is therefore a need for an assembly that provides for the mounting of a high intensity LED package that includes a great deal of heat transfer potential in addition to providing a means for further incorporating the LED into the circuitry of an overall lighting assembly. 
     BRIEF SUMMARY OF THE INVENTION 
     In this regard, the present invention provides an assembly that incorporates a high intensity LED package, such as the Luxeon Emitter Assembly described above, into an integral housing for further incorporation into other useful lighting devices. The present invention can be incorporated into a variety of lighting assemblies including but not limited to flashlights, specialty architectural grade lighting fixtures and vehicle lighting. The present invention primarily includes two housing components, namely an inner mounting die, and an outer enclosure. The inner mounting die is formed from a highly thermally conductive material. While the preferred material is brass, other materials such as thermally conductive polymers or other metals may be used to achieve the same result. The inner mounting die is cylindrically shaped and has a recess in the top end. The recess is formed to frictionally receive the mounting base of a high intensity LED assembly. A longitudinal groove is cut into the side of the inner mounting die that may receive an insulator strip or a strip of printed circuitry, including various control circuitry thereon. Therefore, the inner mounting die provides both electrical connectivity to one contact of the LED package and also serves as a heat sink for the LED. The contact pad at the back of the LED package is in direct thermal communication with the inner surface of the recess at the top of the inner mounting die thus providing a highly conductive thermal path for dissipating the heat away from the LED package. 
     The outer enclosure of the present invention is preferably formed from the same material as the inner mounting die. In the preferred embodiment, this is brass but may be thermally conductive polymer or other metallic materials. The outer enclosure slides over the inner mounting die and has a circular opening in the top end that receives the clear optical portion of the Luxeon LED package therethrough. The outer enclosure serves to further transfer heat from the inner mounting die and the LED package, as it is also highly thermally conductive and in thermal communication with both the inner mounting die and the LED package. The outer enclosure also covers the groove in the side of the inner mounting die protecting the insulator strip and circuitry mounted thereon from damage. 
     Another feature of the outer enclosure of the present invention is that the end that receives the optical portion of the LED package also serves as a reflector for collecting the light output from the LED package and further focusing and directing it into a collimated beam of light. After assembly, it can be seen that the present invention provides a self contained packaging system for the Luxeon Emitter Assembly or any other similar packaged high intensity LED device. Assembled in this manner, the present invention can be incorporated into any type of lighting device. 
     Accordingly, one of the objects of the present invention is the provision of an assembly for packaging a high intensity LED. Another object of the present invention is the provision of an assembly for packaging a high intensity LED that includes integral heat sink capacity. A further object of the present invention is the provision of an assembly for packaging a high intensity LED that includes integral heat sink capacity while further providing means for integral electrical connectivity and control circuitry. Yet a further object of the present invention is the provision of an assembly for packaging a high intensity LED that includes integral heat sink capacity, a means for electrically connectivity and an integral reflector cup that can creates a completed flashlight head for further incorporation into a flashlight housing or other lighting assembly. 
     Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
     FIG. 1 is a perspective view of the LED lighting assembly of the present invention; 
     FIG. 2 is a front view thereof; 
     FIG. 3 is rear view thereof; 
     FIG. 4 is an exploded perspective thereof; 
     FIG. 5 is a cross-sectional view thereof as taken along line  5 — 5  of FIG. 1; and 
     FIG. 6 is a schematic diagram generally illustrating the operational circuitry of present invention as incorporated into a complete lighting assembly. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, the light emitting diode (LED) lighting assembly of the present invention is illustrated and generally indicated at  10  in FIGS. 1-5. Further, a schematic diagram is shown in FIG. 6 generally illustrating the present invention incorporated into a flashlight circuit. As will hereinafter be more fully described, the present invention illustrates an LED lighting assembly  10  for further incorporation into a lighting device. For the purposes of providing a preferred embodiment of the present invention, the device  10  will be shown incorporated into a flashlight, however, the present invention also may be incorporated into any other lighting device such as architectural specialty lighting or vehicle lighting. In general, the present invention provides a means for packaging a high intensity LED lamp that includes integral heat sink capacity, electrical connectivity and an optical assembly for controlling the light output from the LED. The present invention therefore provides a convenient and economical assembly  10  for incorporating a high intensity LED into a lighting assembly that has not been previously available in the prior art. 
     Turning to FIGS. 1,  2  and  3 , the LED package assembly  10  can be seen in a fully assembled state. The three main components can be seen to include a high intensity LED lamp  12 , an inner mounting die  14  and an outer enclosure  16 . In FIGS. 1 and 2, the lens  18  of the LED  12  can be seen extending through an opening in the front wall of the outer enclosure  16 . Further, in FIG. 3 a rear view of the assembled package  10  of the present invention can be seen with a flexible contact strip shown extending over the bottom of the interior die  14 . 
     Turning now to FIGS. 4 and 5, an exploded perspective view and a cross sectional view of the assembly  10  of the present invention can be seen. The assembly  10  of the present invention is specifically configured to incorporate a high intensity LED lamp  12  into a package that can be then used in a lighting assembly. The high intensity LED lamp  12  is shown here as a Luxeon Emitter assembly. However, it should be understood that the mounting arrangement described is equally applicable to other similarly packaged high intensity LED&#39;s. The LED  12  has a mounting base  20  and a clear optical lens  18  that encloses the LED  12  emitter chip (not shown). The LED  12  also includes two contact leads  22 ,  24  that extend from the sides of the mounting base  20 , to which power is connected to energize the emitter chip. Further, the LED lamp  12  includes a heat transfer plate  26  positioned on the back of the mounting base  20 . Since the emitter chip in this type of high intensity LED lamp  12  is four times the area of a standard emitter chip, a great deal more energy is consumed and a great deal more heat is generated. The heat transfer plate  26  is provided to transfer waste heat out of the LED lamp  12  to prevent malfunction or destruction of the chip. In this regard, the manufacturer has provided the heat transfer plate  26  for the specific purpose of engagement with a heat sink. However, all of the recommended heat sink configurations are directed to a planar circuit board mount with a heat spreader or a conventional finned heat sink. Neither of these arrangements is suitable for small package integration or a typical tubular flashlight construction. 
     In contrast, the mounting die  14  used in the present invention is configured to receive the LED lamp  12  and further provide both electrical and thermal conductivity to and from the LED lamp  12 . The mounting die  14  is fashioned from a thermally conductive and electrically conductive material. In the preferred embodiment the mounting die  14  is fashioned from brass, however, the die  14  could also be fabricated from other metals such as aluminum or stainless steel or from an electrically conductive and thermally conductive polymer composition and still fall within the scope of this disclosure. The mounting die  14  has a recess  28  in one end thereof that is configured to frictionally receive and retain the base  20  of the LED lamp  12 . While the base  20  and the recess  28  are illustrated as circular, it is to be understood that this recess is intended to receive the housing base regardless of the shape. As can be seen, one of the contact leads  22  extending from the base  20  of the LED lamp  12  must be bent against the LED lamp  12  base  20  and is thus trapped between the base  20  and the sidewall of the recess  28  when the LED lamp  12  is installed into the recess  28 . When installed with the first contact lead  22  of the LED  12  retained in this manner, the lead  22  is in firm electrical communication with the mounting die  14 . A channel  30  extends along one side of the mounting die  14  from the recess to the rear of the die  14 . When the LED lamp  12  is installed in the mounting die  14 , the second contact lead  24  extends into the opening in the channel  30  out of contact with the body of the mounting die  14 . The heat transfer plate  26  provided in the rear of the LED lamp  12  base  20  is also in contact with the bottom wall of the recess  28  in the mounting die  14 . When the heat transfer plate  26  is in contact with the die  14 , the heat transfer plate  26  is also in thermal communication with the die  14  and heat is quickly transferred out of the LED lamp  12  and into the body of the die  14 . The die  14  thus provides a great deal of added heat sink capacity to the LED lamp  12 . 
     An insulator strip  32  is placed into the bottom of the channel  30  that extends along the side of the mounting die  14 . The insulator strip  30  allows a conductor to be connected to the second contact lead  24  of the LED lamp  12  and extended through the channel  30  to the rear of the assembly  10  without coming into electrical contact with and short circuiting against the body of the die  14 . In the preferred embodiment, the insulator strip  32  is a flexible printed circuit strip with circuit traces  34  printed on one side thereof. The second contact lead  24  of the LED lamp  12  is soldered to a contact pad  36  that is connected to a circuit trace  34  at one end of the insulator strip  32 . The circuit trace  34  then extends the length of the assembly and terminated in a second contact pad  38  that is centrally located at the rear of the assembly  10 . Further, control circuitry  40  may be mounted onto the flexible circuit strip  32  and housed within the channel  30  in the die  14 . The control circuitry  40  includes an LED driver circuit as is well known in the art. 
     With the LED lamp  12  and insulator strip  32  installed on the mounting die  14 , the mounting die  14  is inserted into the outer enclosure  16 . The outer enclosure  16  is also fashioned from a thermally conductive and electrically conductive material. In the preferred embodiment the outer enclosure  16  is fashioned from brass, however, the outer enclosure  16  could also be fabricated from other metals such as aluminum or stainless steel or from an electrically conductive and thermally conductive polymer composition and still fall within the scope of this disclosure. The outer enclosure  16  has a cavity that closely matches the outer diameter of the mounting die  14 . When the mounting die  14  is received therein, the die  14  and the housing  16  are in thermal and electrical communication with one another, providing a heat transfer pathway to the exterior of the assembly  10 . As can also be seen, electrical connections to the assembly  10  can be made by providing connections to the outer enclosure  16  and the contact pad  38  on the circuit trace  34  at the rear of the mounting die  14 . The outer enclosure  16  includes an aperture  42  in the front wall thereof through which the optical lens portion  18  of the LED lamp  12  extends. The aperture  42  is fashioned to provide optical control of the light emitted from the LED lamp  12 . The aperture  42  in the preferred embodiment is shaped as a reflector cone and may be a simple conical reflector or a parabolic reflector. The walls of the aperture  42  may also be coated with an anti-reflective coating such as black paint or anodized to prevent the reflection of light, allowing only the image of the LED lamp  12  to be utilized in the finished lighting assembly. 
     Finally, an insulator disk  44  is shown pressed into place in the open end of the outer enclosure  16  behind the mounting die  14 . The insulator disk  44  fits tightly into the opening in the outer enclosure  16  and serves to retain the mounting die  14  in place and to further isolate the contact pad  38  at the rear of the mounting die  14  from the outer enclosure  16 . 
     Turning now to FIG. 6, a schematic diagram of a completed circuit showing the LED assembly  10  of the present invention incorporated into functional lighting device is provided. The LED assembly  10  is shown with electrical connections made thereto. A housing  46  is provided and shown in dashed lines. A power source  48  such as a battery is shown within the housing  46  with one terminal in electrical communication with the outer enclosure  15  of the LED assembly  10  and a second terminal in electrical communication with the circuit trace  38  at the rear of the housing  16  via a switch assembly  50 . The switching assembly  50  is provided as a means of selectively energizing the circuit and may be any switching means already known in the art. The housing  46  of the lighting device may also be thermally and electrically conductive to provide additional heat sink capacity and facilitate electrical connection to the outer enclosure  16  of the LED assembly  10 . 
     It can therefore be seen that the present invention  10  provides a compact package assembly for incorporating a high intensity LED  12  into a lighting device. The present invention provides integral heat sink capacity and electrical connections that overcome the drawbacks associated with prior art attempts to use LED&#39;s of this type while further creating a versatile assembly  10  that can be incorporated into a wide range of lighting devices. For these reasons, the instant invention is believed to represent a significant advancement in the art, which has substantial commercial merit. 
     While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.

Technology Category: 2