Abstract:
Connector and connector assemblies for use with miniature high power electrical components, and specifically with miniature LEDs. Although the connectors and connector assemblies are designed for use with miniature LEDs, these devices are not so limited and can also be used with other miniature electronic devices. These connectors and connector assemblies provide a mechanical connection between the miniature electronic component and electrical contacts instead of a soldered connection, providing a reliable electrical contact between the component, whether used in a PCB-type drop-in connection or some other connection. The connector also includes a heat sink to remove heat from the connector assembly generated by the LED and provides for a reliable mechanical connection between the LED and heat sink.

Description:
FIELD OF THE INVENTION 
   The present invention is directed to connector assemblies for miniature electronics, and specifically, to connector assemblies for use with miniature LEDS that include heat sinks. 
   BACKGROUND OF THE INVENTION 
   Light emitting diodes (LEDs) are used in a variety of applications and one class of these LEDs has been shrunk so that they can be used in miniature electronics, such as in surface mount applications. These miniature high power LEDs are assembled onto connectors or printed circuit boards (PCBs) as drop-ins, which are then soldered using reflow techniques to provide electrical contact. Difficulties can be encountered with soldering, as reflow can result in poor connections. But soldering also adds processing costs and complexity. 
   These assemblies are also limited with respect to the amount of heat that can be generated, as these assemblies do not incorporate heat sinks and heat dissipation capabilities are limited. The design operating temperature is an important factor in extending the life of an LED-based system, so either minimizing the heat generated, or moving the heat away for the LED can extend the life of the LED. Thus, electrical as well as thermal concerns are important to an effective design. 
   What is needed are connectors or connector assemblies for use with miniature LEDs so that the LED or LEDs can be assembled thereto without the need for soldering. In addition, these connectors or connector assemblies should include means to remove heat when such capability is required. 
   SUMMARY OF THE INVENTION 
   The present invention provides connector and connector assemblies for use with miniature electrical components, and specifically with miniature LEDs. Although the connectors and connector assemblies are designed for use with miniature LEDs, these devices are not so limited and can also be used with other miniature electronic devices. These connectors and connector assemblies provide a mechanical connection with the miniature electronic component that provides a reliable electrical contact between the component whether used in a PCB-type drop-in connection or some other connection. The mechanical connection eliminates the troublesome solder connections that have been used with miniature electronic devices. In addition, the heat sinks reliably remove heat, thereby providing these devices with higher current ratings and longer mean life ratings and usage. 
   The concept can be modularized, so that a heat sink of suitable size can be included with the connector to transfer heat away from the miniature electrical component. The heat sink component can be included integrally in the connector, or can be added as needed to form an assembly. 
   An advantage of the present invention is that it provides a connector that can be integrated into miniature electronics to form reliable connections without the complications and added costs of soldering. 
   Another advantage of the present invention is that it conveniently incorporates a heat sink into the connector design to move heat away from the miniature electronics, thereby preventing heat build-up as a result of heat generation from applied electrical current. This permits the miniature electronics device to operate either at a lower temperature or with higher power requirements (i.e. higher current ratings), or both. 
   Yet another advantage of the present invention is that high power LED assemblies with heat sinks can be mounted remotely from the driver electronics, allowing the light output to be directed where it is needed. 
   Still another advantage of the present invention is that assembly is simplified, as the connection between the connector and the miniature electronic device is a simple mechanical connection. This permits existing miniature electronic devices to be assembled with a mechanical connection to provide a reliable electrical contact, and eliminates the necessity of soldering the miniature electronic device to establish an electrical contact. 
   Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective of an embodiment of a connector assembly of the present invention. 
       FIG. 2A  is an exploded view of the connector assembly of  FIG. 1 . 
       FIG. 2B  is an exploded view of the connector assembly of  FIG. 1  from a second view, omitting some parts for clarity. 
       FIG. 2C  is a cross-sectional view of the connector assembly of  FIG. 1  through the latch structure. 
       FIG. 2D  is a cross-sectional view of the connector assembly of  FIG. 1  through the power contacts. 
       FIG. 3  is a back view of the connector assembly of  FIG. 1  depicting the power contact connections. 
       FIG. 4  is a perspective view of a second embodiment of a stamped connector assembly of the present invention. 
       FIG. 5  is an exploded view of the connector assembly of  FIG. 4 . 
       FIGS. 6-9  are perspective views of the connector assembly of  FIGS. 4 and 5  at various stages of assembly. 
       FIG. 10  depicts compliant contacts between the LED and a Mini-CT connector, without a stamped heat sink. 
       FIG. 11  is a cross sectional view of the connector assembly of  FIG. 6 . 
       FIG. 12  depicts a 2×2 array of the connector assembly of  FIG. 4  assembled onto a light fixture heat sink. 
       FIGS. 13 and 14  depict a perspective front view and back view of a third embodiment of the present invention. 
       FIG. 15A  is an exploded view of the embodiment of  FIG. 13 . 
       FIG. 15B  is an exploded view of the embodiment of  FIG. 13  from a second angle or perspective. 
       FIG. 16  depicts a reverse detail view of the contact cartridge assembly of  FIG. 15A . 
       FIG. 17  is an exploded view of the contact cartridge assembly of  FIG. 16 . 
       FIG. 18  is a cross-sectional view of the connector assembly of  FIG. 13 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is an embodiment of the present invention that depicts a connector assembly  10  that includes a heat sink assembly.  FIG. 2A  is an exploded view of assembly  10  that comprises a lens/LED nest  12  assembled over a miniature LED  14  (miniature LEDs include small surface mountable LEDs such as the LUXEON® Rebel available from Philips Lumileds Lighting Company of the Netherlands and with facilities in San Jose, Calif.), holding LED  14  against heat sink/optical reflector  16  comprising a thermally conductive material. Lens  12  is an optically clear thermoplastic. While shown in  FIG. 1  as having a hexagonal shape, the reflector  16  and lens  12  be any convenient preselected geometry for a particular application, so that it can be round, octagonal, etc. Reflector  16  includes a plurality of arms  40  between apertures  20  that link a center raised pad  41  to the periphery of reflector  43 . Reflector  16  also includes a plurality of tabs  42  located between each pair of arms  40  extending slightly into apertures  20 . Lens  12  includes a plurality of latches  24 , each latch including a first tooth  35  near its end, and a second tooth  36  nearer to the base of the latch on the opposite side of the latch  24  from the first tooth  35 . The latches  24  are inserted through apertures  20 , with each latch flexing inward as its second tooth  36  encounters the adjacent reflector tab  42 . As the heat pad  50  of the LED  14  engages the center pad  41  of the reflector  16 , the arms  40  flex and center pad  41  exerts a force on the LED heat pad  50 . When fully inserted, each latch  24  springs back toward its free state and the second tooth  36  engages tab  42 , thus retaining lens  12  with pressure between center pad  41  and LED heat pad  50  as shown in  FIG. 2C . Arms  40  provide multiple thermally conductive paths between center raised pad  41  and periphery  43  of reflector  16  to guide heat away from LED  14 . Referring to  FIGS. 2A ,  2 B,  2 C and  2 D, power contacts are inserted through a plurality or second set of apertures  28  of connector back  18 , the ends of power contacts  26  extending from either side of connector back  18 , as evident from  FIG. 3  on the power connection side, and toward LED side as evident in  FIG. 2D . The second set of apertures  28  include walls  51  that prevent power contacts  26  from being pressed completely through connector back  18 . Assembly continues as lens latches  24  are inserted through apertures  22 , with each latch  24  flexing outward as its first tooth encounters the side of aperture  22 . As latches  24  are inserted, power contacts  26 , supported by walls  51 , engage LED power pads  52  and provide an electrical path between LED  14  and power connection portion  54  of connector back  18 . When latches  24  are fully inserted, each latch  24  springs back toward its free state as it engages a relieved mating ledge  52  in connector back  18 , thus retaining the assembly against the force of the mated power pins  26 . The first tooth  35  and second tooth  36  are on opposite sides of latch  24  so that engagement of second tooth  36  to tab  42  is not loosened as latch  24  flexes to engage first tooth  35 . The ends  30  of power contacts extending from the connector back  18 , see  FIG. 2D  and  FIG. 3 , can be attached to power wiring. The connector back  18  can be compatible with the commercially available Tyco Electronics Mini-CT connector, available from Tyco Electronics, Middletown, Pa. 
   Heat sink/optical reflector  16  is comprised of a thermally conductive material, preferably stamped or formed from aluminum or stainless steel, although it can be comprised of a thermally conductive polymer. It conducts heat away from the LED to its outer surfaces, where the heat can then be removed by the natural convective flow of air over the heat sink optical reflector. It also reduces heat build up from the assembly as a reflector, which reflects radiant energy in the form of light away from the assembly, rather than absorbing it. 
   A second embodiment of the present invention is depicted in  FIGS. 4-11 . This embodiment is the LED stamped connector assembly  100  comprising a Carclo lens  110  assembled to a thermoplastic lens carrier  112 , which is assembled over a heat sink assembly  120 . An exploded view of LED stamped connector assembly  100  is depicted in  FIG. 5 . Heat sink assembly  120 , shown in  FIG. 6  is comprised of stamped heat sink  126  through which is mounted a plastic contact carrier  128  into which is assembled compliant power contacts  130 , more clearly visible in  FIGS. 8 and 10 . A contact carrier assembly  129  comprising the compliant power contacts  130  assembled into the plastic contact carrier  128  is shown in  FIG. 7 . The contact carrier assembly  129  snaps into the aperture pattern on the top face of stamped heat sink  126  as shown in  FIG. 8 . An LED  124  is positioned into a locator pocket molded into plastic contact carrier  128 , as depicted in  FIG. 9 . Referring back to  FIGS. 5 and 6 , a retention clip  122 , preferably of stainless steel is assembled over LED and snapped into position around the plastic contact carrier. The retention clip  122  includes a pair of apertures  134  (only one of which is visible) that engages protrusion or bump  136  on plastic contact carrier,  FIGS. 5 and 7 . Once engaged, LED is visible through the cut out  138  in top surface of retention clip  122 . Retention clip  122  provides a downward force on LED  124 , which urges LED into mechanical contact with compliant contacts  130  and heat sink  126 . 
   The compliant contacts  130 , urged into contact with the LED  124 , are in communication with a power source. The compliant contacts can be mated to a PCB, which can power them. Alternatively, the compliant contacts  130  can be hard-wired to a power source. As shown in  FIGS. 5 and 11 , contact carrier assembly  129  is mated to a Mini-CT connector  132 , which is connected to a power source.  FIG. 10  shows the detail of the connection of the compliant contacts  130  between LED  124  and Mini-CT connector  132 , the plastic contact carrier  128  having been removed from this view for clarity.  FIG. 11  is a cross sectional view of the contact carrier assembly  129  assembled to heat sink  126  and to Mini-CT connector  132 . 
   In the design depicted in  FIGS. 4-11 , light generated by miniature LED  124  is directed by lens  110 . To reduce heat buildup, heat is conducted away from LED  124  by stamped heat sink  126 , which dissipates the heat. Retention clip  122  is a metal, which imparts a normal force on LED  124  to urge it into contact with compliant power contacts  130 , while pad  200 , integral with LED  124 , is urged into contact with heat sink  126 . It is preferably a metal that has a high mechanical strength such as a stainless steel alloy, although in certain applications, other metals may be used. Stamped heat sink  126  preferably is a metal that has high thermal conductivity and can be formed by stamping, such as a stainless steel alloy, an aluminum or aluminum alloy or a copper and copper alloy. However, it may also be a conductive polymer. Stamped heat sink  126  includes feet that allow heat sink assembly  120  to be securely but removably mounted to a surface, such as a PCB surface or a light fixture heat sink  142 , such as depicted in  FIG. 12  that is provided with features to capture heat sink  126 .  FIG. 11  is a cross-sectional view of the assembly of  FIG. 6 . This view shows the interface between the retention clip  122 , LED  124  and contact carrier  128 . Retention clip applies the force to enable a reliable mechanical contact between LED  124  and compliant contacts, as well as between LED  124  and stamped heat sink  126 . 
   The stamped connector assembly  100  can be arranged into an array formed from a plurality of connector assemblies  100 . A simple 2×2 array  140  is depicted in  FIG. 12 , but this array can be expanded to any desired size. The array can be assembled onto a light fixture heat sink  142  to enhance heat dissipation, to allow the LEDs to be operated at even higher currents. 
     FIGS. 13 and 14  depict a third embodiment of the present invention. An LED connector heat sink assembly  150  is depicted in  FIG. 13 . The back end of the LED connector heat sink assembly  150  is shown in  FIG. 14 . The back end  152  is a Mini-CT connector-compatible, permitting a Mini-CT connector to be inserted into the back end  152 . 
   An exploded view of the LED connector heat sink assembly  150  is depicted in  FIGS. 15A and 15B . Connector heat sink assembly  150  comprises a miniaturized LED  154 , such as the Rebel LED discussed previously. The miniaturized LED  154  is inserted into and positioned in heat sink body  156  and is held in place by contact cartridge assembly  158 . An optional mounting nut  160  having threads  162  may be threaded over optional mating threads  164  on the exterior of heat sink body  156 , to mount the connectorized heat sink to a panel. 
   Contact cartridge assembly  158  is depicted in  FIG. 16 , and in exploded view in  FIG. 17 . Contact cartridge assembly  158  includes a plastic cartridge body  166  that includes a pair of slots  168  extending through the body and tabs  170  extending away from the body opposite the slots. Slots  168  accept compliant power contacts  172  that are positioned therein and which extend from either end of cartridge body  166 . Compliant thermal contact/retention clip  174 , comprising a thermally conductive spring like material, is inserted over tabs  170  of cartridge body  166 . 
   Referring to  FIG. 18 , which is a cross-sectional view of LED connector heat sink assembly  150 , LED  154  is inserted into heat sink body  156 , where LED  154  is visible through an aperture. Contact cartridge assembly  158  is inserted into heat sink body  156 , capturing LED  154  within heat sink body  156  so that LED  154  is positioned in a central aperture of heat sink body  156 . The compliant thermal retention clip  174  is driven against LED  154  as contact cartridge assembly  158  is inserted. Arms  178  of compliant thermal retention clip  174  spring outwardly, engaging retention features  181  in a counterbore in heat sink body  156 , the counterbore configured to accept an end of cartridge assembly  158  that includes retention clip  174 . Thus, a force is exerted that keeps thermal contact region  182  of thermal retention clip  174  in contact with LED heat pad  184 , and keeps power contact tips  183  in contact with power pads  185 , as shown in  FIGS. 15A and 15B . It further maintains sides  186  of compliant thermal retention clip  174  in contact with the inside surface of heat sink body  156 , thus providing the thermal conduction path from the LED  154  to the heat sink body  156 . Power contacts  172  may be wired to a power source or may plug into a PCB from which it derives power. 
   Heat sink body  156  has a central aperture extending longitudinally through the body from a first end to a second end and may be comprised of any thermally conductive material such as a conductive metal, including but not limited to stainless steels, aluminum and its alloys, and copper and its alloys, or of a thermally conductive resin. When the heat sink body comprises a conductive metal, some minor modifications within the skill of the art are required to electrically isolate the heat sink body  156  from the power contacts  172  of contact cartridge assembly. The heat sink body  156  has a predetermined fin pattern extending axially from the body for axial and cross-flow of air to facilitate removal of heat from the heat sink body  156 . Preferably, the heat sink body has a concave conical face to maximize fin area without encroaching on the light path from the LED  154 . This conical face can be coated with a reflective material to further maximize the light output of assembly  150 . Heat from power losses in LED  154  is transferred to heat sink body  156  through the compliant thermal retention clip  174 , which moves heat away from LED  154  and transfers the heat to air passing over the outer surfaces of heat sink body  156 . A more effective transfer of heat away from the LED  154  and heat sink body  156  results in a higher current rating for LED connector heat sink assembly  150 . 
   The present invention can be used with small LEDs, including small surface mountable LEDs such as the LUXEON® Rebel available from Philips Lumileds Lighting Company of the Netherlands and with facilities in San Jose, Calif. The present invention also can be used with the Tyco Electronics Mini CT connectors available from Tyco Electronics, Middletown, Pa. 
   While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.