Patent Application
20090075519
The present invention is directed to electronic components, and more particularly to a connector for mounting an LED to a printed circuit board (PCB).
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.
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.
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.
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.
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.
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.
Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
Referring to
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
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.
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.
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.
Referring next to
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.
Referring next to
Referring next to
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.
