Conductive polymer contacts for surface mount technology connectors

#The invention provides a robust connection interface for surface mount technology (SMT) contacts used in the manufacture of electronic devices that have high area densities or high wear environments, and that accommodates contact surface irregularities without significant wear to the either contact surface.

#In SMT contacts, connector components are applied directly to the surface of a circuit board. The components are secured at specified locations on the circuit board by solder pads that are placed on the circuit board in a suitable process, such as by printing the pads on the board forming a printed circuit board (PCB). The solder pads are then heated and the various components are placed onto the solder pads to be secured to the PCB by the cooling solder pads bonding the components to the PCB.

#In the manufacture of the PCBs, to provide electrical connection to external or peripheral components various SMT style connectors are used, including but not limited to: Land Grid Arrays (LGAs), Ball Grid Arrays (BGAs), Pin Grid Arrays (PGAs), Flexible Flat Cable (FPC) connectors, and Pogo™ contacts. These connectors or components are usually soldered to one side of the circuit board and require a mating connector affixed to the external component.

#The drawings illustrate the best mode presently contemplated of carrying out the disclosure. In the drawings

#FIG. 1 is an isometric view of a prior art surface mount technology flexible printed circuit (FPC) board-to-board female and male connector.

#FIG. 2 is an isometric view of circuit board traces (left) and a matching connector according to one exemplary embodiment of the invention.

#In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense.

#Further, the foregoing summary, as well as the following detailed description of certain embodiments, will be better understood when read in conjunction with the appended drawings. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings

#Looking at FIGS. 2, and 3 one exemplary embodiment of a connector 118 of the invention is illustrated in a connector set 101 including a female connector 103. In the exemplary embodiment the connector 118 is formed as the male connector 118 mounted on flexible printed circuit (FPC) 122 and includes a body 102 formed in any desired or necessary configuration of a non-conductive and optionally flexible material. The body 102 is secured to the FPC in any suitable manner and includes a connection member providing pressure between mating surfaces, such as connector tabs 120 affixed thereto to guide and fix the connector 118 to a separate rigid printed circuit board (PCB) 110 using sockets 114 on the PCB 110. The body 102 of the connector 118 also includes contacts 116 formed of a conductive, isotropic or non-isotropic polymer, or combinations of layers thereof, disposed within channels, apertures or other openings 111 formed in the body 102 of the connector 118. The channels 111 extend completely through the body 102 such that the conductive polymer contacts 116 positioned therein extend the length of the channel 111 with a protrusion 113 on each end of the contact 116 that extend outwardly from each end of the channel 111. The protrusions 113 opposite the FPC 122 each contacts a trace pad 112 on the female connector 103 on the printed circuit board 110. In this manner, the contacts 116, via the protrusions 113, each make electrical contact between traces, wires or other electrical conductors (not shown) disposed in the FPC 122 and the traces 112 to facilitate an electrical connection between the FPC 122 the PCB 110 and can be, positioned in any way to afford contact with desired surfaces on the printed circuit board 110. Further, the size of the protrusions 113 can be selected as desired in order to facilitate the electrical contact of the contacts 116 with the various traces 112 on the FPC 122 and the PCB 110. In one exemplary embodiment, the protrusions 113 can extend outwardly from the channels 111 as shown in FIG. 1 to contact the traces 112, or can be positioned flush with the surface of the body 102, such as shown in FIG. 1 to contact the traces on the FPC 122. In the embodiment where the protrusions 113 extend outwardly form the channel 111, the properties of the polymer forming the contact 116 enable the protrusion 113 to be compressed upon contact with the trace 112 to create the electrical connection between the contact 116 and the trace 112, while also returning to its original configuration upon removal of the compressive force on the protrusion 113. Further, the surface tension of the polymer forming the contact 116 can operate to assist the protrusion 113 to contact the adjacent trace and form the required electrical connection.