Abstract:
A connector for mounting an LED to a printed circuit board (PCB) includes a hollow cylindrical body portion with an interior sidewall that defines a hollow cavity at one end to receive the LED threaded base section. The second end has a plurality of conductive contact elements with which to electrically contact the LED. A first electrical contact element includes at least one prong extending partially into the cavity. The prong is flexible for the threaded portion to pass the prong for insertion, and partially return to electrically engage the threaded portion to maintain the threaded portion inside the cavity. The prong also permits removal of the LED rotationally with respect to the cavity. The contact elements are in electrical communication with the LED and the threaded base section when the threaded base section is inserted within the body portion.

Description:
BACKGROUND 
       [0001]    The present invention is directed to electronic components, and more particularly to a connector for mounting an LED to a printed circuit board (PCB). 
         [0002]    The use of high intensity LEDs for general-purpose illumination, and in specialty lighting applications such as large signs and video display applications, has increased in recent years. Typically LEDs are mounted to PCBs by soldering them directly to the preprinted circuits. PCBs are most commonly manufactured using automated wave soldering techniques for mass production. If an LED fails after the PCB has been manufactured, the PCB is usually discarded and replaced with a replacement PCB, since field soldering of LEDs is, in most cases, inefficient and impractical. Although the cost of a replacement LED is negligible, the cost of labor and downtime associated with field soldering a replacement LED to a PCB is frequently greater than the cost to replace the entire PCB. 
         [0003]    Some special purpose LED connectors have threaded bases and require machined assemblies to receive the threaded bases. These connectors feature multiple interconnecting parts. Internal threads must be machined in a connector body. Threaded LED terminations are accomplished by a screw action that is time consuming and adds to assembly costs. Moreover, the placement of the contacts on the PCB must be tightly controlled for the contact interfaces between the LEDs and the connectors to be reliable. Contact interfaces for the component parts of the PCBs may have a high variability in contact normal loads, which leads to early failures. Conversely, if the contact placement is tightly controlled, the fabrication costs may be greatly increased, making the devices impractical from a cost perspective. 
         [0004]    What is needed is a connector to terminate a threaded LED that is reliable and permits the LED to be urged or snapped into position in the connector in a single motion. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs. 
       SUMMARY 
       [0005]    In one embodiment, the present invention is directed to a connection receptacle for mounting a high powered LED having a threaded base section to a printed circuit board. The connection receptacle includes a hollow cylindrical body portion with an interior sidewall, a first end and a second end opposite the first end. The sidewall defines a hollow cavity adjacent the first end to receive the base section of the LED. The second end has a plurality of conductive contact elements configured to electrically contact the LED. A first electrical contact element includes at least one prong extending partially into the cavity. The prong is sufficiently flexible to allow the threaded portion to pass the at least one prong for insertion, and partially return to engage with the threaded portion to maintain the threaded portion inside the cavity. The prong also is configured to permit removal of the LED rotationally with respect to the cavity. The contact elements are in electrical communication with the LED and the threaded base section when the threaded base section is inserted within the body portion. 
         [0006]    In another embodiment, the present invention is directed to LED assembly. The LED assembly includes an LED having a threaded base section and a core electrode in electrical communication. The core electrode is axially parallel to the threaded base section. A connection receptacle for receiving the LED includes a hollow cylindrical body portion with an interior sidewall, a first end and a second end opposite the first end. The sidewall defines a hollow cavity adjacent the first end to receive the base section of the LED. The second end has a plurality of conductive contact elements with which to electrically contact the LED. A first electrical contact element includes at least one prong extending partially into the cavity. The prong is sufficiently flexible to allow the threaded portion to pass the at least one prong for insertion, and partially return to engage with the threaded portion to maintain the threaded portion inside the cavity. The prong also is also configured to permit removal of the LED rotationally with respect to the cavity. The contact elements are in electrical communication with the LED and the threaded base section when the threaded base section is inserted within the body portion. 
         [0007]    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 
         [0008]      FIG. 1  is an upright perspective view of an LED/connector assembly. 
           [0009]      FIG. 1A  is an exploded view of the the LED/connector assembly. 
           [0010]      FIG. 2  is a reverse perspective view of an assembled LED/connector. 
           [0011]      FIG. 3  is a cross-sectional view through the center of an assembled LED/connector. 
           [0012]      FIG. 4  is an exploded view of the connector portion. 
           [0013]      FIG. 5  is a cross-sectional view of the connector portion. 
           [0014]      FIG. 6  is a perspective view of an alternate contact portion having 3-prongs. 
           [0015]      FIG. 7  is a top plan view of the connector portion. 
           [0016]      FIG. 8  is a perspective view of an alternate embodiment. 
           [0017]      FIG. 9  is a perspective view of the alternate embodiment of  FIG. 8 , and an LED. 
       
    
    
       [0018]    Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Referring to  FIGS. 1-3 , an assembled LED/connector  10  includes an LED assembly  12  inserted into a connection receptacle  14 . A pair of connector contacts  16 ,  18  protrude from the connection receptacle  14 . A core LED electrode  20  extends through the center of the LED assembly  12  and provides an electrical connection to one of two internal LED terminals (not shown). A threaded base-portion  22  of the LED assembly  12  extends from a rim portion  24  that is electrically connected to the remaining internal LED terminal. The rim portion of the LED may be conductive, but is not required to be conductive for the connector to work properly. The internal LED of the LED assembly  12  is electrically connected between the threaded base portion  22  and the core LED electrode  20 . The threaded base portion  22  and the core LED electrode  20  are otherwise insulated from each other to avoid short-circuiting the LED. An exemplary threaded-base integrated LED assembly  12  is manufactured by CAO Group, Inc., of West Jordan, Utah. 
         [0020]    The connection receptacle  14  includes a hollow cylindrical cavity  26  that receives the threaded base portion  22 . The interior cavity  26  of the connection receptacle  14  has a generally straight, smooth sidewall  28  with an inner-diameter that is slightly larger than the outer diameter of the threaded base portion  22  of the LED assembly  12 , so that the threaded base portion  22  can be inserted into the connection receptacle  14  without rotation—i.e., by urging the LED assembly  12  directly downward into the interior cavity  26  of the connection receptacle  14 , as indicated by direction arrow  23  in  FIG. 1A . 
         [0021]    Once the LED assembly  12  is urged into the connection receptacle  14 , a pair of contact elements  16 ,  18  engage the core threaded base portion  22  and the core LED electrode  20 , respectively. The first contact element  16  includes a deflectable prong  30 . The first contact element  16  may be made from electrically conductive structures, such as a metallic foil, e.g., copper alloy conductive strip. Preferably the foil strip is sufficiently flexible to permit the prong  30  to deflect as the threaded base portion  22  is urged into the cavity  26 . The prong  30  engages one of the threads of the threaded base portion  22 , which provides electrical contact and prevents the LED assembly  12  from backing out of the cavity  26 . The LED assembly  12  is secured in position by the prong  30 , and is removable by conventional rotational means—i.e., by rotating the threaded base portion  22  of the LED assembly  12  in the direction in which it is configured to reverse, typically counterclockwise, although opposite-hand thread types exist and function much the same, with opposite rotation for installation and removal. Thus, the LED assembly  12  is installable in the connection receptacle  14  by simply urging it into the cavity  26 , but removable only by rotating it in the appropriate direction. 
         [0022]    The second contact element  18  includes an end portion  32  that is bent or turned back at an acute angle to the contact element  18 . The end portion  32  has an inwardly curved tip portion  34 . The end portion  32  is elastically deflectable, similar to the prong  30  and engages the core LED electrode  20  when the LED assembly  12  is pressed into the cavity  26 . The curvature of the tip portion  34  allows the LED electrode  20  to slidingly engage the end portion  32  in both directions of movement, i.e., so that the end portion  32  does not gouge into the core electrode  20  and prevent its removal. 
         [0023]    The cavity  26  has an inwardly protruding ledge  36  disposed intermediately of the opposite ends of the connection receptacle  14 . The ledge  36  reduces the inner radius of the cavity  26  to trap the core LED electrode  20  and guide it into the lower cavity portion  38 . Preferably, there is a tapered transition segment  40  that connects the lower cavity portion  38  with the ledge  36 , and which helps to center the end of the core electrode into the lower cavity portion  38 . The lower cavity portion  38  has an internal diameter that preferably provides a close clearance fit for the core LED electrode. The end portion  32  protrudes at least partially into the lower cavity portion  38  and presses against the core electrode  20  under spring tension. The flex in the second contact portion  18  from the bent intersection with the end portion  32  provides the spring tension. 
         [0024]    Referring next to  FIGS. 5 and 6 , the connection receptacle  14  is preferably made of a molded, high temperature resin, e.g., glass-filled, nylon-66 or other electrically insulating, high temperature resin, and includes a pair of internal channels  42 ,  44  arranged on opposite sides of the receptacle  14 . The first contact element  16  is installed in the channel  42  that runs adjacent to both the upper cavity  26  and the lower cavity  38  and protrudes from the lower end of the connection receptacle  14 . In one embodiment the first contact element  16  is a flat strip of metal conductor with three step portions  46 ,  48 ,  50  of progressive width. The step portion between  46  and  48  provides a stop limit for seating the contact element  16  when the element is placed in the receptacle  14 . The contact element also has a pair of bent prongs  30 ,  52  that protrude inward. The first prong  30 , as discussed above, retentively and electrically engages the threads on the threaded base portion  22 . The first prong  30  is shown as a single protruding member, however, additional prongs may be included, e.g., two prongs or three prongs arranged in series, which are preferably spaced apart by a single-thread distance for improved engagement with a corresponding number of threads. The second prong  52  deflects to allow it to pass behind a portion of the inner wall of the cavity  26  and spring back to latch in position in an opening (not shown) adjacent to the ledge  36 . 
         [0025]    The second contact element  18  is inserted into a slot  44  in the connection receptacle  14  adjacent to the lower cavity  38 . The contact element  18  includes an intermediate locking member  54 , which slides into the slot  44  of the inner wall, and locks the contact element into position by engagement of detents  56  located on either edge of the locking member  54 . 
         [0026]    Referring next to  FIGS. 6 and 7 , an alternate embodiment shows a novel 3-pronged contact to deflect and mate on threads. Contact portion  16  has three web portions  46   a - 46   c  which may be substituted for the single step portion  46  of the contact portion  16  shown in  FIG. 4 . Two prongs  46   b  and  46   c  project outwardly on opposite sides of the center prong  46   a  and are bent inwardly to partially envelop the circumference of the threaded portion  22 . Deflectable prongs  30   a - 30   c  project inwardly from the respective web portions  46   a - 46   c  to engage the conductive threaded portion  22  of the LED assembly  12 . The distal ends  60   a - 60   c  of prongs  30   a - 30   c , respectively, may be staggered in length to engage the thread portion  22  approximately equally, to cooperate with the helical pitch of the individual threads. In this way, it is apparent that the prongs  30   a - 30   c  are deflected by the threaded portion  22  when the LED assembly  12  is inserted in a first direction indicated by arrow  70 . The prongs  30   a - 30   c  then spring back and mate against the threads of the threaded portion  22  and act as ratchet pawls and electrical contacts to prevent the LED assembly  12  from backing out of the connection receptacle  14  linearly. However, the LED assembly  12  is rotatable about its axis, and can be removed in cooperation with the prongs  30   a - 30   c  by twisting in one rotational direction, as well as further tightened by twisting the threads in the opposite rotational direction. Thus, the LED assembly  12  may be securely installed into the connection receptacle  14  by a pushing motion, or by threading, but the LED assembly  12  is prevented from backing out of the connection receptacle  14  by the prongs  30   a - 30   c , unless the threads  22  are used. 
         [0027]    Referring next to  FIGS. 8 and 9 , in an alternate embodiment, the connector portion  14  may include solder terminals  70  for soldering wires  72  to the connector portion. The LED  12  is inserted into and removed from the connector portion  14  in the same manner as described above. In the embodiment of  FIGS. 8 &amp; 9 , however, the connector portion  14  is configured for attaching leadwires  72  instead of the contact pins described above. The leadwires permit the connector portion  14  to be secured to a surface (not shown) other than a PCB, by a hex nut  74 . 
         [0028]    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.