Patent Application
20170194721
Field of the Invention
The present invention relates to electrical connectors, including separable electrical connectors, used for the interconnection of circuit elements in products such as computers, mobile phones, tablets, laptop computers, digital cameras, medical electronics devices, optoelectronic assemblies, sensors, transducers, automotive electronic assemblies, aerospace electronic assemblies, industrial electronics, or other electronic devices, systems or subsystems, or products containing discrete electronic elements requiring electrical interconnection.
Background of the Invention
Complex electronic devices such as computers and mobile phones require electrical interconnection of various circuit elements, such as printed circuit boards (PCB), flexible printed circuit (FPC) cables, rigid-flex circuits, ceramic substrates, semiconductor package substrates, optoelectronic devices, batteries, and other elements of electronic devices. Frequently, it is desired that these interconnections be separable in order to facilitate low cost and simplified assembly, test, rework, and repair, or to avoid high temperature interconnection methods such as soldering, brazing, or other high temperature attachment methods when certain subcomponents or elements of the assembly are sensitive to elevated temperatures, or for other reasons or combinations of reasons.
For this reason, there is frequently a plurality of separable electrical connectors found in a single electronic device. As these electronic devices evolve to provide increased functionality in smaller form factors, such as for mobile consumer electronic products, the electrical connectors must simultaneously improve in function and performance while decreasing in size, including area of the connector's footprint (x by y area occupied on the mating circuit elements) and its profile (thickness). Low profile connectors also facilitate reduced electrical resistance across the connector, allowing them to carry more power with less temperature increase due to resistive losses, and often enable better signal integrity due to lower inductance and reduced impedance discontinuity.
It is frequently required that these electrical connectors meet stringent performance requirements, such as maintaining high signal integrity of the interconnected electronic signals at high operating frequencies, providing low electrical contact resistance to enable high current capacity with minimal temperature rise, surviving high levels of mechanical shock and vibration without transient or permanent interruptions in the electrical path, maintaining reliable interconnections through various environmental stresses during life of the product, and meeting other stringent performance requirements that are specific to various applications such as aerospace, medical electronics, and other demanding applications. As electronic devices continue to be miniaturized, the interconnection terminals or pads on the circuit elements requiring interconnection are commonly required to be reduced in size (area) and located on finer pitches (spaced closer together), necessitating electrical connectors with improved means for precise and accurate alignment to the circuit elements and with very accurate true position of the contacts in the connector relative to each other and to the position of these alignment means. Manufacturing costs of these connectors must be low to keep pace with the competitive environment and end-product pricing constraints, so connector materials and manufacturing processes must be simple, streamlined and/or low cost.
Some of the better performing connectors with respect to the above criteria are normal force connectors. Normal force connectors typically have electrical spring contact elements emanating from a first surface of the electrical connector. A second, opposing surface may also have electrical spring contact elements emanating from it, or it may have electrical interconnection terminals that are adapted for a different means of assembly and interconnection, such as surface mount soldering. Typically, one or more of the electrical spring contact elements on the first surface of the normal force connector are electrically interconnected to at least one of the electrical spring contacts or interconnection terminals on the second surface of the normal force connector. The electrical spring contact elements of normal force connectors can be modified cantilever beam-like springs, such as in the Neoconix PCBeam™ normal force connectors, or they can be surface-emanating coil springs, or pogo pins, or other springs that are compressed and actuated against a mating conductive terminal by application of force normal to the mating surfaces of the connector and of the mating circuit element. In the case of the PCBeam™ connector, the spring contacts are similar to a cantilever beam spring, as described in a number of US patents including the following:
U.S. Pat. No. 7,371,073 entitled “Contact Grid Array”, issued May 13, 2008, to inventor John David Williams and assigned to Neoconix, Inc., the assignee of the present patent; this patent is sometimes referred to herein as the “Contact Array Patent”, the disclosure of which is incorporated by reference in its entirety;
U.S. Pat. No. 7,056,131 entitled “Contact Grid Array System”, issued Jun. 6, 2006, to inventor John David Williams and assigned to Neoconix, Inc., the assignee of the present patent, the disclosure of which is incorporated by reference in its entirety;
U.S. Pat. No. 7,758,351 entitled “Method and System for Batch Forming of Spring Elements” issued Jul. 20, 2010, to inventors Dirk D. Brown et al. and also assigned to Neoconix, Inc.; this patent is sometimes referred to herein as the “Batch Forming Patent”, the disclosure of which is incorporated by reference in its entirety.
Normal force connectors frequently perform well at surviving mechanical shock and vibration forces which can be experienced during normal use of mobile electronic devices without transient or permanent interruptions in the electrical path, because the retention of the connector in its compressed, actuated state is typically positive to the extent that any potential separation between the connector and the mating circuit element due to these shock or vibration forces is less than the working range of the electrical spring contacts of the connector. In contrast, connectors such as two-piece, mezzanine board to board connectors rely on lateral friction between mating spring elements to provide retention, and ZIF connectors rely on a nonpositive cam-action lid. For this reason, secondary retention mechanisms, such as tape over a ZIF connector lid or a secondary clamp over a board to board mezzanine connector, are frequently implemented. Since space in miniaturized devices is at a premium, this is not ideal. As these connectors continue to be miniaturized to fit into shrinking device form factors, the sensitivity to shock and vibration typically increases due to reduced area for application of retention forces. Frequently, the profile (thickness) of these connectors is well above 1 millimeter, which can be a limiting factor in shrinking the thickness of devices like high end mobile ‘smart-phones’. It is desirable and would be an advance over the current state of the art to provide a connector structure, affixing means, and method of manufacture that offers high signal fidelity interconnections, high mechanical and electrical compliance and working range of the electrical spring contacts, high resistance to mechanical shock and vibration, fine contact pitch, a small footprint for the connector and its retention mechanism, and low connector profile, among other desirable attributes. It would be a further advantage to have electrical connectors with the above advantages, and which could be permanently or semipermanently affixed to at least one of two mating circuit elements being electrically interconnected, such as a PCB or an FPC, without requiring a surface mount assembly process such as a solder reflow based process or a conductive adhesive based process, which have their own inherent reliability issues—such as susceptibility to joint failure under conditions of device dropping, shock and/or vibration—and processing costs and complexities. It would also be a further advantage to avoid the requirement for a complex mechanical mounting and compression mechanism, such as a socket frame and lid, screws, or mechanical clamps, each of which requires substantial use of substrate real estate and may require holes or other penetrations through the substrate that impact substrate wiring density on multiple circuit layers.
The present disclosure relates to electrical connectors for interconnecting circuit elements in an electronic device or subsystem.
One objective of the present invention is to provide a low profile, high performance electrical interconnection means for electrically interconnecting, in a reliable fashion, two circuit elements in an electronic system or device, such circuit elements including but not limited to two printed circuit boards, or a printed circuit board and a flexible printed circuit, or a semiconductor package substrate and a printed circuit board, or a rigid-flex circuit and a flexible or rigid printed circuit, or a socket to a printed circuit board, or a modular subsystem such as a cell phone camera or a sensor to a mating circuit element such as an FPC or a PCB.
It is another objective of the present invention to provide an electrical connector in a form that enables easy and low cost assembly in high volume.
It is a further objective of the present invention to provide an electrical connector which can be permanently or semi-permanently assembled to a mating circuit element. The phrase ‘permanently or semi-permanently assembled to a mating circuit element’, means that the connector is assembled to and retained on a mating circuit element in its compressed and actuated state, whereby a low electrical resistance interconnection is achieved and maintained between the electrical spring contacts on the connector and the respective electrical spring contact terminals on a mating circuit element until purposefully de-mated.
It is another objective of the present invention to thereby simplify further assembly of the electronic device by having one mating surface of the electrical connector actuated and permanently affixed to one circuit element in an electronic assembly. It is a further objective of this invention to provide an electrical connector which can be permanently or semipermanently assembled to a mating circuit element at temperatures less than those required for reflow of eutectic tin lead solders or lead-free solders, given that such elevated assembly temperatures can cause damage to certain sensitive components or devices, such as some optoelectronic assemblies, flash memory devices, MEMS devices, or other temperature sensitive elements in an electronic device or subsystem.
It is a further objective of this invention to provide an electrical connector which can be permanently or semi-permanently assembled to a mating circuit element in a simple fashion which is compatible with high volume, low cost manufacturing.
It is a further objective of this invention to provide an electrical connector which can be permanently or semi-permanently assembled to a mating circuit element without requiring complex and costly tooling.
It is a further objective of this invention to provide an electrical connector which can be permanently or semi-permanently assembled to a mating circuit element such as an FPC or a PCB and which can be assembled and interconnected to that circuit element without requiring any additional hardware or tooling to retain the connector in its compressed and actuated state.
It is a further objective of this invention to provide an electrical connector which can be permanently or semi-permanently assembled to a mating circuit element such as an FPC or a PCB and which can be assembled and interconnected to that circuit element without occupying substantial additional real estate on the connector beyond that which is occupied by the electrical contact elements of the connector itself, so as to facilitate miniaturization and cost reduction of the connector.
It is a further objective of this invention to provide an electrical connector which can be permanently or semi-permanently assembled to a mating circuit element without requiring perforations in the mating circuit element for the purpose of retaining and compressing the connector on the circuit element.
Another objective of the present invention is to provide such a connector also comprising electrical spring contacts having a high degree of mechanical and electrical compliance, thereby providing the interconnection with a high tolerance of mechanical shock and vibration without suffering transient or permanent opens.
In an embodiment of the present invention, an electrical connector with a plurality of conductive spring contacts is retained on a mating circuit element with the conductive spring contacts in a compressed state against mating conductive circuit terminals using an integral attaching material, such that low resistance electrical interconnections are created and maintained between the conductive spring contacts of the electrical connector and mating conductive terminals on the mating circuit element.
In one embodiment, the integral attaching material is a bonding material.
In one embodiment, the integral attaching material is a non-conductive bonding material.
In one embodiment, the integral attaching material is a polymer.
In one embodiment, the integral attaching material is a thermo-plastic polymer.
In one embodiment, the integral attaching material is a thermo-setting polymer.
In one embodiment, the integral attaching material is an adhesive.
In one embodiment, the integral attaching material is an epoxy.
In one embodiment, the integral attaching material is a modified acrylic adhesive.
In one embodiment, the integral attaching material is a sheet adhesive.
In one embodiment, the integral attaching material is a pressure sensitive adhesive.
In one embodiment, the integral attaching material is a homogeneous polymer.
In one embodiment, the integral attaching material is a heterogeneous material, such as an adhesive stabilized by a second material, such as a polyimide film.
In one embodiment, the integral material is a heterogeneous material, such as a bond ply material. In a further embodiment, the bond ply material is comprised of a B-staged, modified acrylic adhesive on both, opposing surfaces of a polyimide film. In one embodiment, the bond ply material is DuPont Pyralux FR bond ply material. In one embodiment, the bond ply material is DuPont Pyralux LF bond ply material.
In one embodiment, the integral attaching material has a plurality of openings corresponding to, and substantially aligned with, the distal ends of the electrical contact springs of an electrical connector.
In one embodiment, the integral attaching material is disposed upon the proximal end of an electrical spring contact, and has one or more openings through which the distal ends of electrical spring contacts emanate.
In an embodiment of the present invention, an electrical connector with a plurality of conductive spring contacts is retained, using a bonding material, on a mating circuit element with the conductive spring contacts in a compressed state and resisting upon electrically conductive terminals on the mating circuit element, such that low resistance electrical interconnections between the electrical spring contacts and the mating conductive terminals on the mating circuit element are obtained. In a further embodiment, the bonding material has clearance openings for the elastic portion of the conductive spring contacts.
In one embodiment, the connector is a normal force connector, and a low resistance electrical interconnection is achieved by applying a force on the connector normal to the surface of the mating circuit element and maintaining that force using a bonding material.
In one embodiment, the connector is a Neoconix PCBeam™ connector. In another embodiment, the connector is a Neoconix XBeam™ connector.
In one embodiment, the electrical spring contacts in their uncompressed state stand proud of the outer surface of the bonding material.
In one embodiment, the bonding material also serves as a hard compression stop to limit the travel of the electrical spring contacts, so as to prevent over-compression of the springs that might otherwise cause plastic deformation, cracking, or other damage.
It should be realized that not all embodiments of the present invention will achieve all of the objectives set forth above—and that the invention may have additional advantages and objectives beyond what are stated in this patent application. One of ordinary skill in the relevant art will understand the principles of the present invention from this document and may choose to achieve some of the objects without achieving other objects and may choose to include certain features of the present invention without employing other features. As such, the discussion of the objectives is for example of the present invention and not in limitation thereof or any implication that all of the objectives have to be met to practice the present invention.
In an embodiment of the present invention, an electrical connector with a plurality of conductive spring contacts is retained on a mating circuit element, with the conductive spring contacts of the connector in a compressed state, using an adhesive material disposed between the connector surface and the mating circuit element, such that low resistance electrical interconnections between the conductive spring contacts and mating conductive terminals on the mating circuit element are obtained. In one embodiment, the connector is a normal force connector, and the low resistance electrical interconnection is achieved by applying a force on the connector normal to the surface of the mating circuit element and maintaining that force using an adhesive material. In one embodiment, the connector is a Neoconix PCBeam™ connector. In one embodiment, the electrical spring contacts in their uncompressed state stand proud of the outer surface of the adhesive material. In an embodiment, the adhesive material is a non-conductive adhesive. In an embodiment, the adhesive material is a polymer. In an embodiment, the adhesive material is an epoxy. In an embodiment, the adhesive material is a woven glass reinforced, B-staged epoxy. In an embodiment, the adhesive material is a sheet material. In an embodiment, the adhesive material is a modified acrylic sheet adhesive. In an embodiment, the adhesive material is a B-staged modified acrylic sheet adhesive. In an embodiment, the adhesive material is a bond ply adhesive. In an embodiment, the adhesive material is a bond ply adhesive comprised of a B-staged modified acrylic adhesive on both surfaces of a polyimide film. In an embodiment, the adhesive material is a DuPont Pyralux LF bond ply material. In a different embodiment, the adhesive material is a DuPont Pyralux FR bond ply material. In an embodiment, the bond ply adhesive has openings corresponding to the locations of the electrical spring contacts. In an embodiment, the openings in the bond ply adhesive allow compression of the electrical spring contacts against a conductive terminal on a mating circuit element without interference of the bond ply with the elastic movement of the spring contact and without its impeding the formation of low resistance electrical interconnections. In an embodiment, the electrical interconnection is comprised of the electrical spring contact of the connector compressed against a conductive terminal on the mating circuit element and retained by an adhesive material surrounding it, which adhesive material has been cured by the application of elevated temperature and pressure.
In an embodiment, the electrical interconnection is comprised of the electrical spring contact of the connector compressed against a conductive terminal on the mating circuit element and retained by an adhesive material surrounding it, said adhesive material being a pressure sensitive adhesive, and which has been bonded by the application of normal force pressure.
In an embodiment, an electrical connector having a first surface with a plurality of conductive spring contacts disposed on, and emanating from, that first surface, has a bonding material disposed on the first surface in the interstitial areas between the electrical spring contact elements. In one embodiment, the adhesive material is disposed on the first surface of the electrical connector in order to bond it to, and retain it on, a mating circuit element with the electrical spring contacts of the connector in compression against conductive terminals on the mating circuit element, so as to form low resistance electrical interconnections to mating conductive terminals on the circuit element.
In an embodiment, an electrical connector has an adhesive disposed on the surface between the electrical spring contact elements, in order to bond it to and retain it on a mating circuit element, so as to form low resistance electrical interconnections to mating conductive terminals on the circuit element.
In an embodiment, an electrical connector having electrically conductive spring contacts is electrically interconnected to an external circuit element in an actuated, compressed state using a bonding material.
In an embodiment, an electrical connector having electrically generally linear, conductive spring contacts is electrically interconnected to an external circuit element in an actuated, compressed state using an adhesive. In another embodiment, the generally linear, conductive spring contacts have an anisotropic grain structure, with the longer dimension of the grains generally parallel to the length of the conductive spring contact.
In an embodiment, an electrical connector is used to electrically interconnect two circuit elements. The electrical connector may be interconnected to a first circuit element using a bonding material to retain it on the first mating circuit element, with the electrical spring contacts of the connector in compression against conductive terminals on the mating circuit element so as to form low resistance electrical interconnections to mating conductive terminals on the circuit element. The electrical connector may be interconnected to a second circuit element separably, using mechanical means other than a bonding material to maintain it in compression against the second circuit element.
In an embodiment, an electrical connector having electrically conductive spring contacts is used to electrically interconnect two circuit elements. The electrical connector may be permanently or semi-permanently interconnected to one circuit element using a bonding material, such as an adhesive, while the electrical interconnection to a second circuit element remains separable, and is held in place and actuated using mechanical means other than an adhesive.
In an embodiment, an electrical connector having electrically conductive spring contacts is used to electrically interconnect two circuit elements. The electrical connector may be permanently or semi-permanently interconnected to one circuit element using a bonding material, such as an adhesive, while the electrical interconnection to a second circuit element is formed using a solder interconnection, such as a eutectic tin lead solder or a lead-free solder such as tin-silvercopper, or a low temperature solder, such as those containing indium or bismuth.
In an embodiment, an electrical connector is used to electrically interconnect a flexible printed circuit (FPC) to a rigid printed circuit board (PCB). The electrical connector has a first plurality of surface emanating electrical spring contacts on a first surface of the connector, and a second plurality of surface emanating electrical spring contacts on a second, opposing surface of the connector. At least one of the electrical spring contacts on the first surface of the connector is electrically interconnected to at least one of the electrical spring contacts on the second surface of the connector. The first surface of the electrical connector is permanently or semipermanently interconnected to the flexible printed circuit using a bonding material, such as an adhesive, to hold it in compression against the FPC, so as to form low resistance electrical interconnections to mating conductive terminals on the FPC. The FPC-connector assembly is interconnected separably to the PCB using mechanical means to actuate and retain the second surface of the connector against the PCB with the second plurality of electrical spring contacts held in compression against the PCB so as to form low resistance electrical connections to conductive terminals on the PCB. In one embodiment, the FPC may require a stiffener to be located on the FPC opposite the connector, in order to facilitate the application of uniform force to the connector when mating it to the PCB. The retention of the connector in compression against the rigid PCB may be accomplished with a mechanical clamp, with screws, or with other mechanical means.
In an embodiment, a normal force electrical connector, having electrical spring contacts emanating from two opposing surfaces, and electrical interconnection means from one connector surface to the opposing connector surface, is used to electrically interconnect a flexible printed circuit (FPC) to a rigid printed circuit board (PCB). The electrical connector is permanently or semi-permanently interconnected to the rigid PCB using a bonding material, such as an adhesive, to hold its elastic, electrical spring contacts in compression against the PCB, so as to form low resistance electrical interconnections to mating conductive terminals on the PCB. The PCB-connector assembly is interconnected separably to the FPC using mechanical means to actuate and retain the connector, so as to form low resistance electrical connections to the FPC. The FPC may require a stiffener to be located on the FPC opposite the connector, in order to facilitate the application of uniform force to the connector.
In an embodiment, the electrical connector is used to electrically interconnect two FPCs. The electrical connector is permanently or semi-permanently interconnected to one of the FPCs using a bonding material, such as an adhesive, to hold it in compression against the FPC and form low resistance electrical interconnections to mating conductive terminals on the FPC. The FPC-connector assembly is interconnected separably to the second FPC using mechanical means to actuate and retain the connector. The FPC may require a stiffener to be located on the FPC opposite the connector, in order to facilitate the application of uniform force to the connector.
In an embodiment, the electrical connector is used to electrically interconnect two rigid PCBs. The electrical connector is interconnected to one of the PCBs using a bonding material, such as an adhesive, to hold it in compression against the PCB and form low resistance electrical interconnections to the mating conductive terminals on the PCB. The PCB-connector assembly is then interconnected separably to the second PCB using mechanical means to actuate and retain the connector.
In an embodiment, the electrical connector is a socket which is used to electrically interconnect a semiconductor package substrate to a PCB or to an FPC. The socket may be permanently or semi-permanently interconnected to the PCB or FPC using a bonding material, such as an adhesive, to hold it in compression against the PCB, so as to form low resistance electrical interconnections to mating conductive terminals on the PCB, while the electrical interconnections between the socket and the semiconductor package remain separable.
In an embodiment, the electrical connector is used to electrically interconnect a module, such as a camera module, a sensor module, an optoelectronic transducer module, or any other type of module in an electronic device, to a PCB or to an FPC. A first surface of the connector may be permanently or semi-permanently interconnected to the module using a bonding material, such as an adhesive, to hold it in compression against the module, so as to form low resistance electrical interconnections to mating conductive terminals on the module, while the electrical interconnections between the connector and the mating FPC or PCB remain separable, and is retained in compression on the FPC or PCB by mechanical means other than a bonding adhesive.
In an embodiment, the electrical connector is used to electrically interconnect a module, such as a camera module, a sensor module, an optoelectronic transducer module, or any other type of module in an electronic device, to a PCB or to an FPC. The electrical connector may be integral to the module, in that the module components, devices, and circuits may mounted within, and/or on a first surface of, the module, and whereby the module may comprise a printed circuit board assembly or package substrate assembly or similar structure, and where the module has a plurality of conductive spring contacts which emanate from a second surface of the module, and which are electrically interconnected with the module electronics. An adhesive is disposed on the second surface of the module, with clearance openings for the conductive spring contacts, such that when the module is mated and compressed against a mating circuit element with a force normal to the mating surface of the mating circuit element, which may be a PCB or an FPC, and with the conductive spring contacts in alignment with respective conductive interconnection terminals on the mating circuit element, the electrical contact springs are compressed, and retained by the adhesive, against the conductive terminals on the mating circuit element and thereby form a low resistance electrical interconnection between the module and the circuit element.
In an embodiment, a first surface of a normal force electrical connector having surface emanating, elastic spring contacts is permanently or semi-permanently assembled to and retained on a mating circuit element in an actuated state using an adhesive material disposed between the connector and the mating circuit element in the interstitial area between the mating conductive interconnection terminals. An actuated state is defined herein as a state whereby the connector is positioned and retained in intimate contact with the mating circuit element so that the electrical spring contacts on the first surface of the connector remain in a sufficiently compressed state against the mating conductive interconnection terminals on the mating circuit element such that a low electrical resistance interconnection is achieved between the electrical spring contacts on the connector and the respective conductive interconnection terminals on the mating circuit element.
In an embodiment, an electrical connector is used to electrically interconnect a first circuit element to a second circuit element. The electrical connector has a first plurality of surface emanating electrical spring contacts on a first surface of the connector, and a second plurality of surface emanating electrical spring contacts on a second, opposing surface of the connector. At least one of the electrical spring contacts on the first surface of the connector is electrically interconnected to at least one of the electrical spring contacts on the second surface of the connector. The first surface of the electrical connector is permanently or semi-permanently interconnected to the first circuit element using a first bonding material, such as an adhesive, to hold it in compression against the first circuit element, so as to form low resistance electrical interconnections between the first plurality of spring contacts and mating conductive terminals on the first circuit element. The second surface of the electrical connector is permanently or semi-permanently interconnected to the second circuit element using a second bonding material, such as an adhesive, to hold it in compression against the second circuit element, so as to form low resistance electrical interconnections between the second plurality of spring contacts and mating conductive terminals on the second circuit element, and thereby creating an electrical interconnection between at least one conductive terminal on the first circuit element and at least one conductive terminal on the second circuit element. The first bonding material and the second bonding material may both be adhesives. The first bonding material and the second bonding material may be identical in nature, composition and properties, including thermal properties. The first bonding material and the second bonding material may be different in nature, composition and properties, such that they may bond at substantially different temperatures. The first bonding material and the second bonding material may have identical or similar glass transition temperatures. The first bonding material and the second bonding material may have substantially different glass transition temperatures. The first and second bonding materials may be thermoplastic materials with identical or similar melting temperatures. The first and second bonding materials may be thermoplastic materials with substantially different melting temperatures. The first and the second bonding materials may be thermosetting materials with identical curing temperatures. The first and second bonding materials may be thermosetting materials having different curing temperatures.
In an embodiment, an electrical connector is permanently or semi-permanently assembled to and retained on a mating circuit element in its compressed and actuated state, using a nonconductive adhesive bond between the connector and the circuit element. Subsequently, a second, opposing surface of the electrical connector is permanently or semi-permanently assembled to and retained on a second mating circuit element in its compressed and actuated state, using a non-conductive adhesive bond between the connector second surface and the second mating circuit element and where the adhesive bonding is achievable at a lower temperature than that for attachment to the first circuit element.
In an embodiment, an electrical connector is permanently or semi-permanently assembled to and retained between two opposing, mating circuit elements to form electrical interconnections between them, whereby the attachments to the two mating circuit elements are achieved sequentially and at different bonding temperatures.
In an embodiment, an electrical connector having electrical spring contacts is permanently or semi-permanently assembled to and retained on a mating circuit element in its compressed and actuated state, using an adhesive material disposed between the connector and the circuit element. In one embodiment, the adhesive flows during bonding and partially or fully encapsulates the electrical spring contact of the electrical connector.
In an embodiment, an electrical connector is permanently or semi-permanently assembled to and retained on a mating circuit element in its compressed and actuated state, using an adhesive material disposed between the connector and the circuit element, whereby the adhesive material resides on a first surface of the electrical connector prior to mating the connector to a mating circuit element.
In an embodiment, an electrical connector is permanently or semi-permanently assembled to and retained on a mating circuit element in its compressed and actuated state, using an adhesive material disposed between the connector and the circuit element, whereby the adhesive material has clearance openings for the electrical spring contacts on the connector and for the interconnection terminals on the mating circuit element.
In one embodiment, the adhesive is a thermoplastic polymer. In one embodiment, the adhesive is a thermosetting polymer.
In one embodiment, the adhesive is a pressure sensitive adhesive (PSA).
In one embodiment, the adhesive is a pressure sensitive film or tape with adhesive properties on both surfaces.
In one embodiment, the pressure sensitive adhesive has clearance openings for the electrical spring contacts, and the spring contacts emanate from a first surface of the connector through the openings in the PSA.
In one embodiment, the adhesive is a cyanoacrylate-based adhesive.
In one embodiment, the adhesive is a modified acrylic adhesive.
In one embodiment, the adhesive is a B-staged sheet of modified acrylic adhesive, such as DuPont™ Pyralux® LF or FR Sheet Adhesive.
In one embodiment, the adhesive is a B-staged sheet of modified acrylic adhesive, such as DuPont™ Pyralux® LF or FR Sheet Adhesive, where the sheet adhesive has clearance openings for the electrical spring contacts, and the spring contacts emanate from a first surface of the connector through the openings in the sheet adhesive.
In one embodiment, the adhesive is a B-staged bond ply material comprised of a modified acrylic adhesive, such as DuPont™ Pyralux® LF or FR Bond Ply, where the bond ply has clearance openings for the electrical spring contacts, and the spring contacts emanate from a first surface of the connector through the openings in the sheet adhesive.
In one embodiment, the adhesive is a B-staged sheet adhesive or bond ply comprised of modified acrylic adhesive, such as DuPont™ Pyralux® LF or FR Sheet Adhesive, which is first applied to the connector using a tack lamination process so that the adhesive remains substantially B-staged and is not fully cured until the connector is assembled to the mating circuit element in its compressed and actuated state, and sufficient pressure and/or temperature is applied to bond and fully cure the adhesive to both the connector and the circuit element, thereby holding the conductive spring contacts of the connector in compression against the mating conductive terminals of the mating circuit element to achieve low and stable electrical resistance interconnections. The sheet adhesive or bond ply adhesive has at least one clearance opening through which one or more conductive spring contacts protrude, so that they may compress and form interconnections to the terminals on the circuit element without interference from the adhesive.
In one embodiment, the adhesive is a bond-ply adhesive, which comprises a stabilizing polymer film such as a polyimide film which has disposed on both a first surface and a second opposing surface a sheet adhesive, such as a modified acrylic adhesive.
In one embodiment, the adhesive is DuPont Pyralux® LF or FR Bond-Ply adhesive.
In one embodiment, the bond-ply adhesive has clearance openings for the electrical spring contacts, and the spring contacts emanate from a first surface of the connector through the openings in the bond-ply adhesive, so that they may compress and form interconnections to the terminals on the circuit element without interference from the bond-ply adhesive.
In an embodiment, the integral attaching material is a thermoplastic material which is heated above its melt transition temperature during attachment to the connector, and which is subsequently heated a second time above its melt transition temperature during mating of the connector to a mating circuit element.
In an embodiment, the integral attaching material is a thermoplastic material which is heated above its melt transition temperature during attachment to the connector, and which is subsequently heated a second time above its melt transition temperature during mating of the connector to a mating circuit element, and whereby the connector can be demated with heat applied locally to the connector to re-melt the thermoplastic material and release the connector. In one embodiment, the thickness of the thermoplastic material is sufficient to limit the compression of the electrical spring contacts of the connector to its elastic range during mating, so that it can be de-mated and re-mated multiple times through the application of localized heat without loss of working range of the electrical spring contacts from plastic deformation.
In an embodiment, the integral attaching material is a B-staged thermosetting adhesive that remains somewhat tacky, so that it may be retained on the substrate in accurate alignment until the assembly is complete.
In an embodiment, the connector is a Neoconix PCBeam™ connector, and the integral attaching material is used in place of a coverlay material, with a plurality of openings corresponding to a plurality of surface emanating electrical contact springs, whereby the integral attaching material also functions as a hard compression stop to limit travel of the electrical contact spring of the connector to its elastic range and to prevent plastic deformation and damage to the spring contact. In one embodiment, the integral attaching material is of sufficient thickness to provide a hard compression stop for the electrical contact spring such that the compression force on the contact spring is below its yield strength.
In an embodiment, a normal force connector such as is described in U.S. provisional Patent Application No. 62/163,539, entitled “Low Profile, Normal Force Connector”, and with an application date of May 19, 2015, said connector, also known as an X-Beam™ connector, having a molded body and cantilever beam-like electrical contact springs emanating above one or both of two opposing surfaces, is permanently or semi-permanently assembled to and retained on a mating circuit element in its compressed and actuated state, using an adhesive material disposed between the connector and the circuit element. In an embodiment, the adhesive material is disposed on a first surface of the molded connector body. The teaching of the patent application identified in this paragraph, including its specification and drawings, is incorporated herein by reference.
In an embodiment, the connector comprises a normal force connector, such as a Neoconix PCBeam™ connector or socket or a Neoconix X-Beam™ connector or socket, or a pogo-pin based connector or socket, or another normal force connector or LGA socket, whereby the electrical contact spring elements of the connector are mated to conductive electrical contact terminals or pads on a first surface of a mating circuit element such as an FPC or a PCB by applying a force to the connector body that is normal to a first surface of the mating circuit element, the electrical contact terminals being disposed upon that first surface of the mating circuit element, and the spring contacts are held in compression against the contact terminals using an adhesive disposed on the connector surface between the contact elements. Such contact terminals can be disposed in a pattern, such as a square grid, in a single row or in multiple rows, in a staggered grid, or in other patterns as benefits the particular application. Many electrical sockets, such as test sockets, burn in sockets, or microprocessor sockets, are also normal force connectors, and frequently have pogo pin type or cantilever beam type contact elements, or other normal force (also known as ‘z-force’) electrical spring contact elements that are actuated and form electrical contact to the mating electrical contact terminals on the mating circuit element when a normal force is applied to the socket body. Often this application and maintenance of normal force requires complex and costly tooling including support frames, bolts, lids, and corresponding holes in the mating circuit element to accommodate the affixing means. Such affixing means can be expensive, and also can occupy precious real estate not only on the surface of the mating circuit element, but also on internal layers, such as the interior circuit layers of a PCB or FPC. Other affixing means for normal force connectors include surface mounted clamping mechanisms that are attached with solder or adhesives. These clamping mechanisms require additional real estate on the mating circuit element, and there is a trade off in how much area is occupied by the clamping mechanism attachment to the circuit element, as more area provides for a more robust connection but requires an increase in the size of the circuit element. If the attachment areas for the affixing hardware are limited in area to reduce use of real estate on the mating circuit element, the affixing hardware attachment is subject to failure from shear forces during drop testing and shock and vibration testing of electronic devices, as well during use of products in the field.
In an embodiment of the present invention, an adhesive, disposed on a first surface of a normal force connector, is used in place of mechanical affixing means such as frames, screws, or clamps, to assemble and retain the connector, in an actuated state, with the electrical spring contacts in compression against a mating surface of a circuit element such as an FPC or PCB. The normal force connector in this embodiment has electrical spring contact elements emanating from the first surface of the connector, and the adhesive would be disposed between the electrical spring contacts, but would not be disposed on the electrical spring contacts themselves. In order to mate and retain the normal force connector in its fully compressed state to achieve a low resistance electrical contact with the electrical contact terminals on a mating circuit element, the first surface of the connector would be aligned to, and compressed against, the mating contact terminals on the PCB or FPC. The adhesive material disposed between the contact elements on the first surface of the connector would be treated to form a bond with the surface of the mating circuit element, between the electrical contact terminals. Alternatively, the adhesive material could be disposed on the first surface of the mating circuit element, between the conductive mating terminals, or on both opposing surfaces.
The bonding material used in many embodiments of this invention can be of many different types, depending on the requirements of the application. It can be a thermoplastic material or a thermoset resin such as an epoxy or an acrylic adhesive. It can be a film adhesive or a bond ply adhesive, or can be dispensed or printed or sprayed or otherwise applied as a viscous liquid or paste. In the case of thermosetting adhesives, the adhesive may be applied as a liquid or paste on the connector surface, between the electrical spring contacts, and then partially cured, known as B-staging, so that the adhesive no longer is substantially tacky and no longer flows readily, simplifying handling of the connector. When the connector is to be interconnected to a mating circuit element, the connector is aligned to and compressed against the mating circuit element, and an appropriate temperature and/or pressure cycle is applied to form an adhesive bond between the connector and the mating circuit element and to fully cure the adhesive. Alternatively, a thermoset adhesive or other adhesive can be applied to the mating circuit element, between the contact terminals, rather than to the connector surface.
In one embodiment of the present invention, instantaneous bonding of the connector to a mating circuit element can be achieved by using a pressure sensitive adhesive (PSA), such as a two sided PSA bonding film, sometimes referred to as a double stick tape. In another embodiment, a high strength, two sided PSA film would have release layers on both sides of the film. The PSA film and release layers would have a pattern of openings that match the layout of the electrical spring contacts of the connector, with these openings being of appropriate size and shape to enable free movement of the electrical spring contacts. A first surface of the PSA with pre-cut openings would be disposed on and bonded to a first surface of the electrical connector, following the removal of the release layer from that first surface of the PSA, and the normal force electrical spring contacts emanating from that first surface of the connector would protrude through the respective openings in the PSA layer, with the distal ends of the contacts being a further distance from the first surface of the connector body than the second, outwardly disposed surface of the PSA. Such a connector could then be permanently mounted to a mating circuit element by removing the second release layer from the second, opposing surface of the PSA, aligning the connector to the electrical contact terminals on the mating circuit element, and applying normal force to the electrical connector to compress the electrical spring contacts of the connector against the electrical contact terminals sufficiently to achieve low resistance electrical interconnection, and also sufficient pressure between the PSA second surface and a first surface of the mating circuit element to form a strong adhesive bond. Once the mating pressure is released, the PSA maintains a mechanical bond between the connector and the mating circuit element such that the electrical contact springs would remain in the compressed state and a low resistance electrical interconnection would be formed and maintained. In another embodiment of the present invention, the two surfaces of the PSA have differing adhesive strengths. In an embodiment, a stronger PSA adhesive film is used on the side of the PSA tape attached to the connector, and a lower adhesive strength film is used on the side of the PSA tape to be attached to the mating circuit element. In this way, reworkability of the interconnection may be achievable.
In a further embodiment of the present invention, the openings in a PSA film could be mechanically punched, laser machined, drilled, or otherwise formed, with the opening locations and dimensions designed so as to ensure there is no interference between the PSA film and the interconnections nor with the mechanical movement of the electrical spring contacts during interconnection to the mating circuit element.
In another embodiment of the present invention, a PSA is applied in a pattern to the connector surface or to the surface of a mating circuit element in liquid or paste form, through printing or dispensing or spraying, and is cured to form a tacky, solid PSA film.
In another embodiment, the adhesive is a pressure sensitive adhesive film, which has a differential adhesive strength or ‘tack’ levels on opposing surfaces, and the lower tack level surface being separable and re-bondable to a mating circuit element, to allow repair or rework, while the higher tack level maintains its adhesive bond to the connector, but both tack levels being sufficient to maintain the spring contacts in a fully compressed and actuated state whereby low electrical resistant interconnections are achieved and maintained.
In another embodiment of the present invention, a cyanoacrylate liquid adhesive is applied to the mating surfaces between the connector and the mating circuit element in the interstitial areas between the electrical spring contacts, and forms a near instantaneous bond when the material is compressed to a very thin bond line to retain the connector in the fully actuated configuration to achieve a low resistance and reliable interconnection.
In a preferred embodiment of the present invention, a normal force connector is comprised of an insulating substrate having a first surface and a second opposing surface. A plurality of electrical spring contacts is disposed upon and attached to the first surface of the connector, and emanate outwardly from that first surface. At least one of the spring contacts is isolated from the others of the plurality of contacts on the first surface of the connector. The elastic spring contacts each comprise a base portion attached to the connector insulating body and in electrical contact with a conductive via, and a distal portion extending above the first surface and over a planar portion of the first surface. The conductive via forms an electrical connection between the electrical spring contact on the first surface of the connector and the second opposing surface of the connector. A partially cured adhesive layer, such as a B-staged thermosetting adhesive layer, is disposed over the base portion of the electrical spring contacts and in the areas between the electrical contacts, with clearance openings in the adhesive layer for the distal ends of the electrical spring contacts so as not to interfere with their ability to compress against and form an electrical interconnection with the interconnection terminals on a mating circuit element. The thickness of the adhesive layer is less than the height of the electrical spring contact above the first surface of the connector, to allow sufficient compression distance and force of the electrical spring contact against a mating conductive terminal to create an electrical interconnection with low and stable electrical resistance. The connector can be mated, electrically interconnected and permanently affixed to the mating circuit element by applying sufficient normal force to substantially compress the distal ends of the spring contacts against the electrical contact terminals on the mating circuit element, coupled with the application concurrently or subsequently of sufficient temperature and/or pressure to flow, bond and fully cure the adhesive layer to bond the connector to the mating circuit element in the regions between the distal ends of the electrical spring contacts. In this manner, the first surface of the electrical connector is permanently or semi-permanently mated to the mating circuit element. The second surface of the electrical connector may also comprise a plurality of electrical spring contacts disposed upon and attached to it, and emanating outward from that second surface, where at least one of the plurality of contacts on the second surface is electrically connected to an electrical spring contact on the first surface through the conductive via. In one embodiment, the size of the clearance openings in the adhesive layer are reduced during curing of the adhesive material under compression.
In another embodiment of the present invention, a normal force connector is comprised of an insulating substrate having a first surface and a second opposing surface. A plurality of electrical spring contacts is disposed upon and attached to the first surface of the connector, and emanate outwardly from that first surface to a distance greater than a dimension x. At least one of the spring contacts is isolated from the others of the plurality of contacts on the first surface of the connector. A second plurality of electrical spring contacts is disposed upon and attached to the second surface of the connector insulating substrate, and emanate outwardly from that that surface to a distance greater than a dimension y. The elastic spring contacts on the first and second surfaces each comprise a base portion attached to the connector insulating body and in electrical contact with a conductive via, and a distal portion extending above the first or second surfaces respectively, and over a planar portion of the first or second surface respectively. An adhesive layer, which may be a partially cured (B-staged) thermosetting adhesive layer, or another adhesive type, of a thickness less than x, and preferably of a thickness less than 0.8x, is disposed over the base portion of the contacts and on the first surface of the insulating substrate. The adhesive layer may be a bond-ply adhesive having a central stabilizing film such as polyimide, with both opposing surfaces having a corresponding adhesive layer on it, such as a modified acrylic adhesive. The adhesive layer preferably has openings aligned with the electrical spring contacts and of appropriate size and shape so as to prevent interfere of the adhesive layer with the displacement of the electrical spring contacts during compression, to enable their low resistance interconnection to conductive terminals on a mating circuit element. A coverlay of thickness less than y, and preferably of thickness less than 0.8y, is disposed over the base portion of the second plurality of electrical spring contacts and on the second surface of the insulating substrate, and having clearance openings for the distal ends of the electrical spring contacts. At least one of the electrical spring contacts on the second surface of the connector is electrically interconnected to at least one of the electrical spring contacts on the first surface of the connector. The first surface of the connector can be mated, electrically interconnected and permanently affixed to a mating circuit element by applying sufficient normal force to substantially compress the distal ends of the spring contacts on the first surface of the connector against the electrical contact terminals on the mating circuit element, coupled with sufficient temperature and/or pressure to flow, bond and fully cure the adhesive layer to bond the connector to the mating circuit element in the regions between the distal ends of the electrical spring contacts. The second surface of the connector can be separably mated and electrically interconnected to a second mating circuit element, using mechanical means to retain the connector in position and under compression against the second mating circuit element. In a preferred embodiment, the adhesive layer on the first surface of the electrical connector acts as a hard compression stop, and the thickness of the adhesive layer on the first surface of the electrical connector is sufficient such that when the adhesive makes contact with the surface of the first mating circuit element, the electrical spring contacts on the first surface of the connector remain in their elastic range, and therefore are not plastically deformed. In one preferred embodiment, the adhesive material is a low flow material, such that during curing it retains a high flow viscosity and its thickness does not decrease by more than 50%. In another preferred embodiment, the adhesive material is a bond ply material, whose overall thickness decreases by less than 25% during bonding and curing. In some embodiments of the present invention, distance x is substantially equal to distance y.
Various other options exist for the adhesive layer disposed on the first surface of the insulating substrate of a connector as described in the above embodiments, and in some embodiments disposed over the base portion of a cantilever beam-like electrical spring contact. The adhesive layer may be a bond ply material, such as DuPont Pyralux LF or FR bond ply. These materials consist of a B-staged, acrylic-based adhesive on either side of a polyimide film. The polyimide provides dimensional stability and strength, and the acrylic adhesive provides bonding ability. These materials can be pre-patterned so as to provide a pattern of openings that match the pattern of electrical spring contacts on the electrical connector. The patterned bond ply adhesive can be aligned to and preliminarily bonded to the connector, such that the bond ply overlays the base portions of the contacts while the distal ends protrude through and emanate from the openings in the bond ply adhesive to a distance above the connector's first surface greater than the height of the adhesive above the connector's first surface. The thickness of the adhesive layer can be chosen to optimize performance of the electrical spring contact, such that it is thin enough to allow sufficient compression of the electrical contact spring against a mating conductive terminal to provide an electrical interconnection with low and stable electrical resistance, while being thick enough to prevent over compression of the electrical contact spring, thereby preventing plastic deformation and compression set of the spring. To form the permanent electrical interconnection to a mating circuit element, the connector may be aligned to the mating circuit element contact terminals, normal force applied to compress the spring contacts against the contact terminals, and sufficient temperature and/or pressure is applied to enable the adhesive to flow, wet to the mating surfaces, fully cure and thereby bond the connector to the mating circuit element, thus maintaining the spring contact elements in a sufficiently compressed state where a low resistance electrical connection is maintained.
In another embodiment of the present invention, a bonding material, such as a pressure sensitive adhesive, is disposed onto portions of the surface of one piece of a two piece, mezzanine connector, such as a board to board connector, in which the primary retention mechanism between the mating electrical contacts is laterally induced frictional forces. The adhesive material reduces the probability of an intermittent or extended interruption of the electrical interconnection path through the two halves of the connector, often known as the header and the socket, through separation of the connector header and socket as a result of shock or vibration stresses on the connector, such as might be experienced during testing or field life of a portable electronic device. In a preferred embodiment, the adhesive is a pressure sensitive adhesive film, which has a differential tack levels on opposing surfaces, and the lower tack level surface being separable and re-bondable.
It should be noted that the invention has been described with reference to illustrative embodiments for the purposes of demonstrating the principles and concepts of the invention. The invention, however, is not limited to these examples, as will be understood by persons of skill in the art in view of the description being provided herein. Many modifications may be made to the embodiments described while still achieving the goal of the invention.
Persons of skill in the art will understand that these and other modifications may be made and that all such modifications are within the scope of the invention.
A series of figures is provided to illustrate some, but not all, embodiments of the present invention.
The electrical connector 80 shown in
An array of electrical spring contacts 74 of the electrical connector 70 are variously electrically interconnected to various USB terminals on USB connector tab 78. The array of electrical spring contacts 74 on the electrical connector 70 forms the interconnection between the USB connector 78 and a main logic board or mother board in an electronic device such as a laptop computer or mobile phone. The electrical connector 80 of the present invention provides the same interconnection between a device's main logic board and a USB connector or port while utilizing much less area on the main logic board, and requires no extraneous tooling, simplifying assembly and reducing manufacturing (assembly) cost.
Adhesive may carried on a sheet of bonding material, and openings 96 may be pre-formed in the bonding material prior to its attachment to the first surface of connector body 86. The adhesive carried on the sheet of bonding material 88 may be a B-staged, or partially cured, thermosetting adhesive. It may also be a heterogeneous material, such as a bond-ply material, comprising an adhesive layer on either side of a stabilizing film or sheet, such as a polyimide film or a metal sheet. The film or sheet may provide mechanical and dimensional stability to the adhesive layers. The openings 96 may be created by mechanical punching, laser ablation, mechanical drilling, plasma etching, or by other means as may be known to one skilled in the art. The thickness of the sheet carrying the bonding material 88 may be chosen to limit the total displacement of the electrical spring contact elements 90 to a predominately elastic range, where little or no plastic deformation of the spring contact occurs upon full compression to a level coplanar with the surface of bonding material 88. As such, bonding material 88 may act as a hard compression stop. The sheet of bonding material 88 may be used to bond the connector body 86 to a mating circuit element, in a state where electrical spring contact elements 90 are in alignment with, and compressed against, mating interconnection terminals on the mating circuit element. In the case of a thermoplastic bonding material, the connector body 86 would be aligned to and compressed against a mating circuit element, and then pressure and/or sufficient temperature would be applied to melt the thermoplastic and allow it to form intimate contact with the mating circuit element, at which point it would be cooled in order to form a semi-permanent bond to the mating circuit element. In this manner, the bonding material would maintain the connector in a compressed and actuated state against the mating circuit element such that its electrical spring contacts form low resistance electrical interconnections to interconnection terminals on the mating circuit element. In another embodiment, the bonding material may be a B-staged, thermosetting adhesive material, and the bond to a mating circuit element may be formed by the application of normal force and elevation of temperature to cause the adhesive to liquefy, flow and cure.
In one embodiment, second surface 213 of connector 206 may be mounted on a second circuit element which may be, for example, a flexible printed circuit, or a rigid printed circuit board, using surface mount attachment methods to reflow the solder bumps 214 onto electrical connection terminals on the flexible printed circuit or rigid PCB. Subsequently, first surface 211 of connector 206 may be aligned to and compressed against a first mating circuit element, such as a rigid printed circuit board, with distal ends 218 of electrical spring contacts 216 aligned to and in electrical contact with electrical connection terminals on the PCB. First surface 225 of bonding material 224 would then be bonded to the mating surface of the PCB in the regions between distal ends 218 of electrical spring contacts 216.
A second sheet material 256 having a first surface 262 and a second, opposing surface 264, also has a plurality of openings 263 which are substantially aligned to electrical spring contacts (not visible in this view) disposed on second surface 248 of connector substrate 244. Sheet material 256 may be a bonding material, such as a bond-ply material, as described for sheet material 254 which is laminated to the opposing first surface 246 of connector substrate 244. As such, it may be a sheet adhesive, or a bond ply adhesive with an adhesive film on either side of a support film, such as polyimide. As such, the sheet 256 may be used to bond connector second surface 248 to a second mating circuit element. In an alternative embodiment, sheet 256 is a coverlay material, comprised of a bonding material on first surface 262, and a non-bonding material, such as a fully cured thermosetting polyimide, on second surface 264. In this embodiment, first surface 262 of sheet 256 would be aligned and bonded to second surface 248 of connector manufacturing panel 242. Outer surface 264 of sheet 256 would not form a bond to the surface of a second mating circuit element, but would serve as a hard compression stop to prevent over-compression of the electrical spring contacts on second surface 248 of connector panel 242. In this embodiment, first surface 260 of sheet 254 would be bonded to first surface 246 of connector panel 252, and second surface 258 of sheet 254 would be bonded to a mating circuit element, forming a permanent electrical interconnection between the connector and the mating circuit element; however, second surface 264 of second sheet 256 residing on second surface 248 of connector panel 242 would form a separable interconnection with a second mating circuit element.
Connector body 501 has a first surface 502 and a second surface 510. A plurality of electrical spring contacts 504 are disposed on first surface 502, and a plurality of electrical spring contacts 512 are disposed on second surface 510. Contacts 504 have a proximal end 508 which is affixed to first surface 502 of connector body 501, and a distal end 506 emanating outwardly above first surface 502. Contacts 512 have a proximal end 516 which is affixed to a second surface 510 of connector body 501, and a distal end 514 emanating outwardly above second surface 510. At least one contact 504 on first surface 502 is electrically interconnected to at least one contact 512 on second surface 510 through an interconnection circuit path 518, which may be a plated via such as a plated through hole. A first non-conductive bonding material 503 is disposed upon first surface 502 of connector body 501. A non-conductive material is disposed on second surface 510 of connector body 501. As shown in
When first surface 502 of connector 500 is mated to a mating circuit element, such as an FPC or a PCB, normal force is applied to compress distal ends 506 of elastic, conductive spring contacts 504 against conductive interconnection terminals on the mating circuit element, in order to form low resistance electrical interconnections. While surface 502 is compressed against the mating circuit element, bonding material 503 may be treated so as to form an adhesive bond to the mating circuit element. The adhesive bond preferably has sufficient adhesive strength and the bond is durable enough to maintain the springs in the fully compressed position against the mating circuit terminals throughout the useful life of the product.
When second surface 510 of connector 500 is mated to a second mating circuit element, such as an FPC or a PCB or a module or a substrate, normal force is applied to compress distal ends 514 of elastic, conductive spring contacts 512 against conductive interconnection terminals on the second mating circuit element, in order to form low resistance electrical interconnections. Since non-conductive material 505 is not a bonding material, it does not form an adhesive bond to the second mating circuit element, and external clamping hardware is necessary to maintain normal force between the connector and the circuit element to maintain a low resistant and stable electrical interconnection. This electrical interconnection can therefore be separated and reconnected, such as may be desirable for testing, repair, and/or rework of elements in an electronic system.
In another embodiment of the present invention, both materials 503 and 505 are bonding materials, and are designed to form adhesive bonds to mating circuit elements so as to maintain electrical spring contacts 504 on first connector surface 502 and electrical spring contacts 512 on second connector surface in a compressed and mating configuration against interconnection terminals on mating circuit elements.
Materials 503 and 505 also function as compression hard stops for electrical spring contacts 504 and 512 respectively. The thickness of materials 503 and 505 may be chosen such that they allow sufficient displacement of distal ends 506 and 514 of spring contacts 504 and 512 respectively, such that they apply enough pressure and sufficiently wipe against mating conductive circuit terminals on mating circuit elements, yet to prevent over-compression of the spring contacts 504 and 512 whereby they may yield plastically and may lose mechanical integrity or electrical integrity of the interconnection.
Of course, many modifications and adaptations to the preferred embodiment disclosed above are possible without departing from the spirit of the present invention, Further, some features of the disclosed embodiment can be used to advantage without the corresponding use of other features disclosed in the description. As such, the disclosure should be considered as a teaching of various aspects of the present invention which can be put together in various ways by a man of ordinary skill in the art to which this invention applies. For example, the electrical connection may be made semi-permanent if desired, allowing for the connection to be suspended for one reason or another—and then for the connection to be re-assembled as desired, for example, with a different connection. As such, the present invention may use a thermoplastic material for the bonding compound to allow for the separation of the elements if desired. Alternatively, if disconnection of elements is not desired, then the bonding agent may be a thermo-setting material. Also, the method of creating the connection has been disclosed with some specificity, but other securing materials are known and can be used to advantage—and the method of securing the components together might be pressure in place of (or in addition to) heat to engage the bonding material. Thus it will be appreciated by those of ordinary skill in the relevant art that many modifications to the present invention can be used without departing from the spirit of the present invention and it is possible to use some components of the invention without using other components disclosed herein.
The present patent application claims the benefit of provisional patent application Ser. No. 62/275,720 filed Jan. 7, 2016 and entitled “Low Profile Self-Clamping Normal Force Electrical Connector and Method of Manufacture”. The specification and drawings of this provisional patent application are hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62275720 | Jan 2016 | US |
