Electrical connectors – Preformed panel circuit arrangement – e.g. – pcb – icm – dip,... – With provision to conduct electricity from panel circuit to...
Reexamination Certificate
2001-01-02
2001-11-13
Luebke, Renee (Department: 2833)
Electrical connectors
Preformed panel circuit arrangement, e.g., pcb, icm, dip,...
With provision to conduct electricity from panel circuit to...
C439S591000
Reexamination Certificate
active
06315576
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to interposer assemblies used for forming electrical connections between spaced contact pads on circuit members.
DESCRIPTION OF THE PRIOR ART
Interposer assemblies form electrical connections between densely spaced contact pads on opposed parallel circuit members. Interposer assemblies are used wherever connections are required between very closely spaced or dense contact pads. The assemblies are well suited for use in electronic devices including computers, cell phones, digital assistants, notebook computers and the like. The assemblies enable a reduction in the size and weight of the electronic devices.
The pads on the circuit members are arranged in identical patterns. The interposer assembly includes an insulating plate and a plurality of through-contacts carried in the plate and arranged in the same pattern as the pads on the circuit members. The contacts project above the top and bottom sides of the plate. The interposer assembly is sandwiched between the two members which are held together with the contacts in the plate forming electric connections between aligned pairs of pads.
Interposer assemblies form electrical connections between contact pads arranged in a very close or dense proximity to each other. The pads may be arranged on a one millimeter center-to-center grid. Each assembly may have as many as 961 contacts. Four assemblies are conventionally mounted on a single frame with a total of 3,844 contacts in the frame.
In addition to requiring contacts which can be spaced very close to each other, the contacts must make reliable electrical connections with the pads when the assemblies are sandwiched between the circuit members. Failure of a single contact to make a reliable connection renders the entire frame useless.
The individual electrical contact in the assembly acts as a spring that extends or compresses in response to the circuit members moving away or towards one another. The contact is compressed and deforms elastically when sandwiched between the contact pads. The contact must be able to extend outwardly when the circuit members move apart and compress when the circuit members move back together.
Interposer assemblies must occupy a minimum width between the circuit members. This requires that the individual electrical contacts in the assembly have a limited height. Yet the contacts must possess the required resiliency for maintaining reliable electrical contact with the pads throughout repeated cycles of extension and compression.
Further, the contacts must be compressed with a low mechanical closure force when the interposer assembly is sandwiched between the circuit members. Low closure force is required in order to prevent undue stress on the contact or circuit member. A high closure force could distort or possibly break the contact or the circuit member. Permanent distortion or deformation of the contact member may reduce or destroy the resiliency of the contact. The contact cannot lose resiliency to the extent that the contact is unable to maintain reliable electrical connections between the pads.
Conventional interposer assemblies use contacts which occupy a relatively large amount of space in the supporting plate making it difficult to meet closely spaced grid requirements. These assemblies are relatively expensive to manufacture and assemble. Contacts may be accidentally displaced prior to sandwiching of the assemblies between circuit members.
SUMMARY OF THE INVENTION
The invention is an improved interposer assembly including metal through contacts confined in closely spaced passages extending through an insulating plate. The contacts are compact, permitting use of the assembly to form electrical connections between very closely spaced contact pads.
The contacts include spring portions which when compressed are elastically bent to form wiped pressure connections with opposed pads and reduce the force necessary to sandwich the interposer assembly between the circuit members. The resiliency of the spring portions maintains reliable electrical connections between the pads. The low closure force reduces the risk of damage to an overlying substrate and allows a large number of contacts in the assembly. The wiped electrical connections between the contacts and the circuit pads form low resistance electrical connections between the adjacent pairs of pads and permit installation of the interposer assemblies in user's facilities. The assemblies need not be installed in clean rooms.
The disclosed interposer assemblies use plates and contacts which are easily and inexpensively manufactured and assembled. The plate is a one-piece design and includes through passages with contact retention projections extending into the passages. The contacts each include a central portion and upper and lower spring arms joining the central portion and extending from the central portion to outer ends. Contact noses on the ends of the spring arms are normally spaced apart a distance greater than the thickness of the plate. Retention legs extend inwardly from the contact noses and away from the central portion to free ends of the contact.
The contacts are readily inserted into the passages to snap or latch over the projections. The projections cooperate with the contacts to hold the contacts in place in the passages prior to sandwiching of the assemblies between circuit members.
In a first embodiment each contact retention projection includes a sloped camming surface facing one side of the plate. The through contacts are inserted into the plate from the side adjacent the camming surfaces. During insertion, cam followers on the lead ends of the contacts engage the camming surfaces and are guided over the retention projections. When fully inserted, the retention projections extend between the free ends of the contacts. The contacts are loosely held in the passages. When compressed, the contacts establish reliable wiped contacts with opposed pads.
In a second embodiment each contact retention projection includes sloped camming surfaces provided on both sides of the projection. The camming surfaces extend to the adjacent walls of the contact passages and assure that during insertion of the contacts into the passages the lead ends of the contacts are guided smoothly over the projections and do not hang up in the corners or junctions between the projections and the adjacent walls.
The through contacts may be inserted from either side of the plate. During insertion, cam followers on the lead ends of the contacts engage camming surfaces and are guided past the projections which then hold the contacts in place.
When a contact is positioned in a through passage, rounded surfaces at the free ends of the contact are located adjacent the camming surfaces on opposite sides of the projection. The camming surfaces hold the contact loosely within the passage for floating engagement with opposed contact pads and formation of reliable wiped pressure connections with the pads. The free ends of the contacts are held within the thickness of the plate to limit contact float. When the assembly is sandwiched between the circuit members, the free ends of the contacts engage and then slide on the camming surfaces.
In third through fifth embodiments, the through contacts may also be inserted from either side of the plate. When the assembly is sandwiched between the circuit members, the free ends of the contacts do not engage the walls of the plate. The spring arms are free to extend or compress in response to the circuit members moving away or towards one without the ends of the contacts engaging the plate.
In the third through fifth embodiments each contact retention projection includes sloped camming surfaces provided on both sides of the projection to facilitate insertion of the contacts from either side of the plate. The central portion of each metal contact includes a retention recess and upper and lower retention portions on either side of the recess. After the contacts are inserted into the passages, the projections extend into the retention recesse
Hammond Briggitte R.
InterCon Systems, Inc.
Luebke Renee
Thomas Hooker, P.C.
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