The present invention generally relates to the field of circuit board connectors and more particularly relates to a flex connector for making high speed, high density, shielded, electrical interconnections.
In electronic systems using printed circuit boards or flexible (flex) circuits, it is necessary to provide electrical connector assemblies to make a variety of electrical interconnections. The complexity of many printed circuit substrates and the space constraints present in many electronic systems require electrical connector assemblies capable of making a large number of interconnections in a limited space. An electrical connector assembly typically includes a pair of connector structures that interface with one another to form a plurality of electrical interconnections. Each connector structure must be capable of making a large number of interconnections to an interface on a printed circuit substrate. In addition, the connector structures ordinarily must be made separable from one another to enable the printed circuit substrates to be disconnected and exchanged for upgrade, repair or modification.
Many existing separable connector assemblies use a large number of metal pins of various designs to interface between the connector structures and printed circuit substrates. The pins are electrically coupled to conductive contacts on each connector structure. When a connector structure is engaged with another connector structure to form a separable connector assembly, the contacts interface with additional contacts on the other connector structure. The pins typically are surface-mounted to pads or soldered into plated thru holes on the printed circuit substrate on which the connector structure is mounted. The pins and pads are electrically and mechanically connected with solder. The pads are electrically coupled to one or more conductive traces on the printed circuit substrate. The solder electrically interconnects the contacts on the connector structure and the traces on the printed circuit substrate via the metal pins. The use of separable connector assemblies having metal pins has been recognized as a standard way to interface with printed circuit substrates. However existing separable connector assemblies using metal pins suffer from a number of disadvantages.
For example, in many connector assemblies, the pins include a bent portion that extends beyond the periphery of the connector structure to engage a pad on the printed circuit substrate. The extension of the pin beyond the periphery of the connector structure increases the amount of substrate surface area required by the connector assembly, and thus the footprint of the connector assembly is increased. The extension of the pin also increases the length of the electrical signal path between the contacts on the connector structure and the traces on the printed circuit substrate. In addition, the bent portion of the pin can act as a lever arm during engagement and disengagement of the connector assembly, applying stresses that can damage the solder joints formed with the pads.
Moreover, at higher interconnection densities, the metal pins must be made with smaller sizes and smaller pitch to fit a larger number of interconnections within a given space. The production of reduced pin sizes dictated by aggressive spacing requirements can be very costly and tests the limits of present manufacturing capabilities. Even if manufacturing capabilities exist, however, the reduced size tends to produce structurally weak pins that are easily damaged. In addition, the reduced pitch and size complicate both alignment of the pins with the pads, and the placement of the pins within the connector structure.
Finally, for the traditional pin and socket connector assembly to provide high speed electrical connection, each individual pin and socket must be shielded against electromagnetic interference (EMI) and radio frequency interference (RFI). The shielding process creates an extremely bulky product that may not fit within the confines of the space available to make such connections.
The disadvantages associated with existing connector assemblies demonstrate a need for an improved connector for making high speed, high density, shielded, impedance controlled electrical interconnections. Specifically, there is a need for a connector that is capable of making a large number of interconnections in a limited space while still maintaining a high speed, low noise connection. Moreover, there is a need for a connector that is mechanically able to minimize deformation caused by stress applied to the connector surface. In addition, there is a need for a connector that provides for EMI and RFI shielding without significantly increasing the bulk of the connector itself.
The flex connector assembly of the present invention overcomes the disadvantages of the prior electric connectors.
A flex connector assembly is provided having a plug assembly and a receptacle assembly for electrically connecting with the plug assembly. The plug assembly includes a plug housing, a first plug interface surface and a plug flex circuit having a first portion with a plurality of conductive protrusions thereon, wherein the plug flex circuit is fixed in the plug housing such that the conductive protrusions are positioned on the first plug interface surface. The receptacle assembly includes a receptacle housing, a first receptacle interface surface and a receptacle flex circuit having a plurality of conductive protrusions thereon, wherein the receptacle flex circuit is fixed in the receptacle housing such that the conductive protrusions are positioned on the first receptacle interface surface. Each of the conductive protrusions of the plug assembly are aligned to contact one of the conductive protrusions of the receptacle assembly when the plug assembly and receptacle assembly are connected. To provide EMI and RFI shielding, the housing of the plug and receptacle assemblies are preferably made of conductive metallic material or from a metallized material.
The flex connector assembly of the present invention can be used to make electrical connections in a variety of electronic equipment, including, but not limited to, computers, Internet boxes, telephone switching gear and video monitors. The use of conductive protrusions allows the flex connector to make a large number of electrical interconnections in a limited space. Moreover, the conductive protrusions are resistive to mechanical deformation caused by stress applied to the connector surface.