Maintenance of uniform impedance profiles between adjacent contacts in high speed grid array connectors

#This invention relates generally to electrical contacts that are especially suitable for use in high speed, grid array connectors. More particularly, the invention relates to electrical contacts having resilient retention members that retain the contacts within a connector base and provide for a generally uniform impedance profile between adjacent contacts.

#Typical electrical connectors comprise a connector base made of an insulating material, such as plastic, for example. A plurality of electrical contacts are retained in the connector base. In a so-called “grid array” connector, the contacts are arranged in an array. Such connectors typically include contacts that are retained in the base by virtue of respective retention members that deform the insulating material when the contact is pressed into the base.

#FIG. 1 depicts a pair of typical prior art contacts 10 retained in a connector base 14. Each contact 10 has a retention member 12. Retention members 12 as depicted in FIG. 1 are often referred to as “barbs.” When a contact 10 is pressed into the connector base 14, the retention member 12 deforms a wall W of the base 14. For example, the retention member 12 may penetrate the material from which the base 14 is formed. Thus, the contact 10 is retained in the base 14.

#The invention is further described in the accompanying drawings in which:

#FIG. 1 depicts a pair of typical prior art contacts retained in a connector base;

#FIG. 2 is a plot of impedance between adjacent prior art contacts, such as those depicted in FIG. 1;

#FIG. 3 is a partial perspective view, and FIG. 4 is a longitudinal view, of a preferred embodiment of a contact 110 according to the invention. As shown, the contact 110 may include a receptacle portion 122 that is adapted to receive a complementary electrical contact (not shown), an insertion portion 124 that is adapted to be inserted into a connector base (see FIG. 6), and a plate portion 128 connecting the receptacle portion 122 with the insertion portion 124. As shown, the insertion portion 124 can include a compliant “eye in the needle” fit feature. A beam portion of the contact 117 extends between the receptacle portion and the insertion portion. As shown in FIGS. 3 and 4, the beam portion 117 may include two beam members 117A, 117B.

#The contact 110 includes a retention member 112 extending at an angle (e.g., generally perpendicular) to the plate portion 128 along a length L of the plate portion 128 between the receptacle portion 122 and the insertion portion 124. The retention member 112 is adapted to retain the contact 110 within the connector base, and to deform upon insertion of the contact 110 into the base to cause a generally straight edge to be formed along the portion of the contact that is inserted into the base. The generally straight edge provides a generally uniform impedance profile between adjacent contacts in the connector. As shown, the contact 110 may include more than one retention member 112, each extending along a respective length of the contact 110.

#In a preferred embodiment, the retention member 112 has a resilient beam portion 116 that is adapted to deform, upon insertion of the contact 110 into the connector base, to form the generally straight edge. The contact 110 may include a gap 120 proximate the resilient beam portion 116. The gap 120 allows for resiliency (or “springing action”) in the beam portion 116 and thus encourages the beam portion 116 to deform upon insertion of the contact 110 into the connector base. A deflection member 118 may extend from the beam portion 116. The deflection member 118 is adapted to deform the resilient beam portion upon insertion of the contact into the connector base.