The subject matter herein relates generally to socket connectors configured to electrically connect to printed circuit boards, and more specifically, to an electrical contact grid array for use in socket connectors.
The ongoing trend toward smaller and faster electrical components and higher density electrical circuits has led to the development socket connectors for electrically connecting printed circuit boards to integrated circuit packages. Known socket connectors have an open field of contacts in an array. Some of the contacts are designated as signal contacts used to transmit data or convey power, while other contacts in the array provide ground shielding for the signal contacts. In some known socket connectors, each signal contact or pair of signal contacts is surrounded by a group of ground contacts. For example, the contact array may include many parallel rows of contacts. A single signal contact may be shielded by ground contacts on either side of the signal contact in the same row, as well as by ground contacts in adjacent rows. The ground contacts may be balls, beams, or pins that are similar to, if not identical to the signal contacts. For example, although each signal contact may be surrounded by several ground contacts, the ground contacts are spaced apart from one another and may be relatively narrow, such that gaps between the ground contacts in the open contact array may limit the amount of shielding provided by the ground contacts. As the signal transmission speeds increase, adequate shielding of the signal contacts requires additional ground contacts that are located closer together, which may substantially increase the cost of the socket connectors.
A need remains for a low-cost electrical contact grid array that provides enhanced electrical shielding performance.
In an embodiment, an electrical contact grid array is provided that includes a board having a top side and an opposite bottom side, a plurality of signal conductors mounted to the board, and a plurality of ground shield structures mounted to the board. Each of the signal conductors includes an upper signal contact extending beyond the top side of the board for electrically connecting with a corresponding mating contact of a mating circuit board. Each of the ground shield structures includes at least one ground contact disposed above the top side of the board that defines an upper annular shield. The upper annular shield circumferentially surrounds at least one of the upper signal contacts.
In another embodiment, an electrical contact grid array is provided that includes a board having a top side and an opposite bottom side, a plurality of signal conductors mounted to the board, and a plurality of ground shield structures mounted to the board. The board defines holes extending through the board from the top side to the bottom side. Each of the signal conductors includes an upper signal contact extending beyond the top side of the board, a lower signal contact extending beyond the bottom side of the board, and an intermediate portion disposed within a corresponding one of the holes in the board. Each of the ground shield structures includes an upper annular shield defined by at least one upper ground contact, a lower annular shield defined by at least one lower ground contact, and mounting posts extending through the holes in the board. The mounting posts connect the upper ground contacts to the lower ground contacts. The upper annular shield of each of the ground shield structures circumferentially surrounds at least one of the upper signal contacts. The lower annular shield of each of the ground shield structures circumferentially surrounds at least one of the lower signal contacts.
In another embodiment, an electrical contact grid array is provided that includes a board having a top side and an opposite bottom side, a plurality of signal conductors mounted to the board, and a plurality of ground shield structures mounted to the board. Each of the signal conductors includes an upper signal contact extending beyond the top side of the board for electrically connecting with a corresponding mating contact of a mating circuit board. Each of the ground shield structures includes at least one ground contact disposed above the top side of the board and defining an upper annular shield. The upper annular shield circumferentially surrounds at least one of the upper signal contacts. The ground shield structures are made of one or more of a conductive polymer material or an electrically lossy material.
One or more embodiments of the inventive subject matter described herein provide an electrical contact grid array. The electrical contact grid array includes multiple shielded conductor sets mounted to an electrically insulated board. Each shielded conductor set includes at least one signal contact and a ground shield structure that circumferentially surrounds the at least one signal contact to provide electrical shielding for the at least one signal contact. The circumferential or annular footprint of the ground shield structure may provide enhanced electrical shielding for the one or more signal contacts surrounded by the ground shield structure, relative to known contact arrays that use multiple narrow ground contacts in the same and adjacent rows as one or more signal contacts to provide electrical shielding. For example, the ground contacts in known contact arrays may have the shape of pins, deflectable beams, compressible beams or barrels, or the like, and may be spaced apart from one another by gaps. Due to the narrow shapes of the ground contacts and the gaps therebetween, the ground contacts of known contact arrays only circumferentially surround a portion of the one or more signal contacts, which limits the electrical shielding performance. The ground shield structures of the electrical contact grid array described herein provides enhanced electrical shielding because the ground shield structures surround a greater portion of the one or more signal contacts than the ground contacts of the known contact arrays, such as surrounding a full perimeter of the one or more signal contacts or surrounding a majority of the perimeter, such as at least 75% of the perimeter.
The electronic package 120 is configured to be loaded onto the socket connector 110 such that the electronic package 120 is received within the housing 116. A mating surface 130 of the electronic package 120 engages the shielded conductor sets 126 of the electrical contact grid array 124. When loaded onto the socket connector 110, the electronic package 120 is electrically connected to the circuit board 114 via the electrical contact grid array 124. For example, the shielded conductor sets 126 may be interposed between contact pads (or other electrical elements) on the mating surface 130 of the electronic package 120 and corresponding contact pads (or other electrical elements) on the circuit board 114. The electronic package 120 may be a chip or an integrated circuit such as, but not limited to, a central processing unit (CPU), microprocessor, or an application specific integrated circuit (ASIC). Although the electrical contact grid array 124 is shown in
The illustrated portion of the electrical contact grid array 124 includes six shielded conductor sets 126 mounted to the board 128. The electrical contact grid array 124 may include any number of shielded conductor sets 126, such as 10, 100, 1000, or more shielded conductor sets 126. In an embodiment, the shielded conductor sets 126 are arranged in multiple parallel rows 206 along the top side 202 of the board 128. Each shielded conductor set 126 includes a ground shield structure 208 and at least one signal conductor 210. The ground shield structures 208 and the signal conductors 210 are mounted to the board 128. The ground shield structures 208 are configured to circumferentially surround the signal conductors 210 to provide electrical shielding for the signal conductors 210.
Each signal conductor 210 includes an upper signal contact 212 that extends upward beyond the top side 202 of the board 128. In an embodiment, the upper signal contact 212 has a barrel shape, as shown in more detail in
Only one signal conductor 210 is disposed within the interior region formed by the upper annular shield 216 in the illustrated embodiment. The signal conductor 210 is spaced apart from the ground shield structure 208 and does not engage the ground shield structure 208. For example, an annular region 218 of the board 128 is defined along the top side 202 of the board 128 between an outer perimeter 220 of the upper signal contact 212 and an interior edge 222 of the upper ground contact 214. The board 128 is electrically insulative, and the annular region 218 electrically insulates the signal conductor 210 from the ground shield structure 208 that surrounds and shields the signal conductor 210. Since the ground shield structure 208 defines the upper annular shield 216 that surrounds a full perimeter of the upper signal contact 212, the shielding for each signal conductor 210 is accomplished by the single corresponding ground shield structure 208 that surrounds that signal conductor 210. Unlike known open contact field arrays, electrical shielding for each signal conductor 210 is not accomplished via multiple discrete ground contacts, such as four, six, or eight ground contacts, located around the signal conductor 210. As a result, the electrical contact grid array 124 can reduce the number of discrete ground contacts in the array, which may reduce cost. Furthermore, the electrical contact grid array 124 can have more flexibility with regard to the locations and spacing of the signal conductors 210. Since the signal conductors 210 are surrounded by a single ground shield structure 208, the signal conductors 210 do not have to be arranged in rows surrounded by four, six, or eight discrete ground contacts.
The ground shield structure 208 of the illustrated shielded conductor set 126 includes at least one lower ground contact 304 (for example, two lower ground contacts 304 as shown in
In the illustrated embodiment of
In the illustrated embodiment shown in
In an alternative embodiment, the shielded conductor sets 126 do not extend fully through the board 128. For example, the shielded conductor sets 126 are mounted to the board 128 and only extend from the top side 202 or the bottom side 204. In such an embodiment, the annular shield 306 defined by two curved ground contacts 304 shown in
The ground shield structure 208 includes mounting posts 404 connecting the upper ground contact 214 to the lower ground contacts 304. The mounting posts 404 may be cylindrical with generally the same diameters. In an embodiment, the intermediate portion 402 of the signal conductor 210 is cylindrical and has a diameter that is approximately the same as the mounting posts 404. Although the board 128 is not shown in
Additional reference is made to
The board 128 is made of an electrically insulative material. For example, the board 128 may be made of a polyimide. The board 128 may have a thickness of about 1-10 millimeters, such as about 5 millimeters. In another embodiment, the board 128 may be a different electrically insulative substrate, such as an epoxy resin, glass, or the like.
The upper ground contact 214 that defines the upper annular shield 216 is disposed above the top side 202, the lower ground contacts 304 that define the lower annular shield 306 are disposed below the bottom side 204, and the mounting posts 404 are located within corresponding outer holes 502B. In an embodiment, the ground shield structure 208 is molded in-situ on the board 128. As a result, the upper ground contact 214, the lower ground contacts 304, and the mounting posts 404 are integrally formed with one another. Since the upper and lower ground contacts 214, 304 have curved lengths that extend between the outer holes 502B along the top and bottom sides 202, 204 of the board 128, there is no risk of the ground shield structure 208 dismounting from the board 128.
As shown in
The signal conductor 210 and the ground shield structure 208 are both electrically conductive. Optionally, the signal conductor 210 may be of a conductive material that has a lower electrical resistivity than a conductive material that forms the ground shield structure 208. Therefore, the signal conductor 210 may have a greater electrical conductivity than the ground shield structure 208. In an embodiment, the ground shield structure 208 may be formed of a lower cost conductive material than the conductive material of the signal conductor 210 in order to reduce costs. For example, the ground shield structure 208 could include a metal, such as nickel, that is cheaper than a metal used in the signal conductor 210, such as silver.
The signal conductor 210 may be made of one or more metals (e.g., silver, copper, gold, or a metal alloy), one or more metals dispersed in a polymer material (e.g., a lossy material), a conductive polymer, or the like. In an embodiment in which the signal conductor 210 is compressible, the signal conductor 210 may be a lossy material or a conductive polymer. In another embodiment in which the signal conductor 210 is a deflectable beam or a pin, the signal conductor 210 may be a metal or metal alloy.
In the one or more embodiments in which the ground shield structure 208 is molded in-situ on the board 128, the ground shield structure 208 is a lossy material or a conductive polymer. For example, the lossy material or the conductive polymer material may be molded in-situ on the board 128 using a mold that is coupled to the board 128. The ground shield structure 208 made of the lossy material or the conductive polymer may be at least partially compressible. In an alternative embodiment, the ground shield structure 208 may be assembled onto the board 128, such as by coupling the upper ground contact 214 to the lower ground contacts 304 via the mounting posts 404. The ground shield structure 208 may be assembled on the board 128 using an adhesive, soldering, a fastener, or the like. In such an alternative embodiment, the ground shield structure 208 may be made of one or more metals (e.g., nickel, silver, copper, or a metal alloy), a lossy material, a conductive polymer, or the like.
As used herein, a conductive polymer refers to an organic polymer that conducts electricity. In general, conductive polymers include a carbon chain having alternating single and double bonds. The conductive polymers are typically doped to increase the conductivity by adding or removing electrons at the outer orbitals. Examples of conductive polymers include polyacetylene, polyaniline, polypyrrole, and the like. In an embodiment, the conductive polymer may be a silicon polymer that defines a matrix used to hold solid or plated metal particles comprised of, for example, silver, nickel, copper, and/or the like.
As used herein, a lossy material includes conductive particles dispersed within a dielectric or insulative material. The conductive particles may be filler elements (or fillers) and the dielectric material may be a binder that is used to hold the conductive particles in place. The conductive particles used as fillers may include metal, carbon and/or graphite formed as fibers, flakes, powder, or other particles. Combinations of fillers may be used in some embodiments, such as metal plated (or coated) particles. Silver and nickel may be used to plate particles. Plated (or coated) particles may be used alone or in combination with other fillers, such as carbon flakes. The filler particles may be present in a sufficient volume percentage to allow conducting paths to be created from particle to particle. The binder material may be a thermoplastic material (e.g., a liquid crystal polymer), an epoxy, a thermosetting resin, and/or an adhesive. The binder material is configured to facilitate the molding of the lossy material into the desired shape. Due to the dispersion of the conductive particles in the binder material, the lossy material is less conductive than the conductive material that forms the signal conductor 210.
It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the various embodiments without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The patentable scope should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
As used in the description, the phrase “in an exemplary embodiment” and the like means that the described embodiment is just one example. The phrase is not intended to limit the inventive subject matter to that embodiment. Other embodiments of the inventive subject matter may not include the recited feature or structure. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
Number | Name | Date | Kind |
---|---|---|---|
6231352 | Gonzales | May 2001 | B1 |
6388208 | Kiani | May 2002 | B1 |
7503768 | Tutt | Mar 2009 | B2 |
7549871 | Pennypacker et al. | Jun 2009 | B2 |
8968007 | Kuwahara | Mar 2015 | B2 |
9059545 | Mason | Jun 2015 | B2 |