Patent Publication Number: US-8118604-B2

Title: Socket connector having electrical element supported by insulated elastomer

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a socket connector, and more particularly to a socket connector featured with a plurality of contact terminal units each comprises an insulated elastomer with a contact terminal supported thereon. 
     2. Description of the Related Art 
     With the development of technology, electrical socket connectors, which typically categorized into LGA and PGA in view of their mating interface with the electronic devices, have widely implemented in computers and other electrical devices for transmitting signals and conductive current between a printed circuit board (PCB) and an integrated circuit (IC) package. 
     A typical LGA socket connector comprises a plastic housing (such as terminal carriers) and multiple metal copper alloy terminals. As the market asks for more pin counts and smaller socket connector in dimension, a design of a new type LGA socket connector becomes more and more challenging due to a space required for terminal arms and an increasing loading force. 
     U.S. Pat. No. 7,658,616 submitted by IBM on Dec. 4, 2008 discloses a related land grid array (LGA) socket connector. The land grid array (LGA) socket connector comprises an insulating carrier plane and at least one interposer mounted on a first surface of said carrier plane. 
     The interposer selectively has a hemi-toroidal, conical, dome-shaped conic section, generally cylindrical or hemi-spherical configuration in transverse cross-section and is constituted of a dielectric elastomeric material. A plurality of electrically-conductive elements are arranged about the surface of said at least one hemi-toroidal interposer and extend radially inwardly and downwardly from an uppermost end thereof to electrically contact with an electrically conductive pad. 
     The insulating carrier plane has at least one via formed therein. The electrically-conductive pad extends through said at least one via and has portions contacting with the upper surface of said insulating carrier plane. The electrically-conductive elements each comprises a plurality of metallic strips contacting with an upper surface of said pad. The interposers of essentially conical or dome-shaped conic sections are arranged in pairs and in groups with a predetermined number of said interposers. In each said group, the electrically-conductive elements of each said interposers joint with proximate said at least one via in said insulating carrier plane and contact with said pad to form a common connection at a lower surface of said insulating carrier plane, and each of the interposers in one group differs in height from another one in another group. 
     One of the problems is that when the electrically-conductive elements become smaller and smaller, the electrically-conductive element tends to crash or deform beyond its yielding point easily such that a permanent deformation will be encountered. Once the electrically-conductive elements are crashed, it is unlikely to provide sufficient normal force which is absolutely required for a reliable and robust interconnection. Accordingly, once the electrically-conductive element becomes smaller and smaller, an auxiliary support is therefore required. 
     Hence, an improved socket connector is required to overcome the disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a socket connector having terminal units with simple configuration and good elasticity to prevent being crashed. 
     To achieve the above-mentioned object, a socket connector adapted for electrically connecting an integrated circuit (IC) package comprises a base comprising a plurality of passageways extending vertically therethrough, a plurality of terminal units received in the passageways, the terminal units each comprises an insulated elastomer acting as a resilient portion and an electrical element supported thereon, the electrical element comprises a first contact portion and a second contact portion extending out of the insulated elastomer and sandwiching the insulated elastomer therebetween. 
     Other features and advantages of the present invention will become more apparent to those skilled in the art upon examination of the following drawings and detailed description of preferred embodiments, in which: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an assembled, perspective view of a socket connector in accordance with a preferred embodiment of the present invention; 
         FIG. 2  is an exploded, perspective view of the socket connector shown in  FIG. 1 ; 
         FIG. 3  is an exploded, perspective view of a terminal unit of the socket connector shown in  FIG. 2 ; 
         FIG. 4  is an assembled, perspective view of the terminal unit shown in  FIG. 3 ; 
         FIG. 5  is a side view of the terminal unit shown in  FIG. 4 ; 
         FIG. 6  is a second embodiment of the terminal unit shown in  FIG. 4 ; 
         FIG. 7  shown a terminal unit in  FIG. 6  is assembled to the insulative housing; and 
         FIG. 8  is a cross-sectional view along line  8 - 8  of  FIG. 7 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     Reference will now be made in detail to the preferred embodiment of the present invention. 
     Referring to  FIGS. 1-2 , a socket connector  100  in accordance with a preferred embodiment of the present invention is adapted for electrically connecting an integrated circuit (IC) package (not shown) to a printed circuit board (not shown). The socket connector  100  comprises an insulative housing  1  and a plurality of terminal units  2  assembled on the insulative housing  1 . 
     Referring to  FIG. 2 , the insulative housing  1  includes a rectangular base  10  and four peripheral walls  11  surrounding the base  10 . The peripheral walls  11  extend over the base  10 . The base  10  together with the peripheral walls  11  define a space for receiving the IC package (not shown). The base  10  defines a plurality of passageways  101  extending therethrough and arranged in a rectangular array for receiving a corresponding number of terminal units  2  therein. 
     A number of supporting portions  102  extend upwardly from a top surface of the base  10  and are adjacent to the peripheral walls  11 . There are also a number of projections  103  extending from the top surface of the base  10  and are located between two adjacent supporting portions  102 . The supporting portions  102  and the projections  103  jointly support the IC package (not shown) so as to avoid damaging of the terminal units  2 . A pair of notches  111  is defined at a middle of the two opposite periphery walls  11  respectively for conveniently taking the IC package (not shown) out. 
     Referring to  FIGS. 3-4 , the terminal units  2  each comprises an insulated elastomer  21  and an electrical element  22  supported thereon. The insulated elastomer  21  is configured to a helical configuration or other adequate configuration to provide additional support thereof for compacting along with the electrical element  22  and extension to strengthen the electrical element  22  and can provide the terminal units  2  with additional elasticity. The insulated elastomer  21  has an upper surface  212  and a lower surface  213  opposite to each other. The insulated elastomer  21  defines a through hole  211  extending therethrough. Referring to  FIG. 6 , shown a second embodiment of the terminal units  2  of  FIG. 4 , the difference is the upper surface  212 ′ and the lower surface  213 ′ of the insulated elastomer  21 ′ are configured to polygonal shape due to the plurality of ribs  211 ′ on the surface of the column-shaped insulated elastomer  21 ′ along a up to down direction. Referring to  FIG. 7-8 , when the terminal unit  2 ′ is assembled to the passageway  101  of the insulative housing  1 , the ribs  211 ′ interference with the insulative housing  1  to make the terminal unit  2 ′ positioned in the passageway  101  securely. 
     The electrical element  22  is made of metal sheet and comprises a spring body portion  220  with an S-shaped configuration, a first contact portion  221  extending from the upper end thereof for connecting with the IC package, and a second contact portion  222  extending from the lower end thereof for connecting with the printed circuit board. The first contact portion  221  and the second contact portion  222  are configured to a U-shaped configuration or other adequate configuration to hook with the upper surface  212  and the lower surface  213  respectively. When the electrical element  22  are assembled to the insulated elastomer  21 , the S-shaped body portion  220  is received in the through hole  211  of the insulated elastomer  21 , the second contact portion  222  engages with the lower surface  213  of the insulated elastomer  21  and the first contact portion  221  is bending from the body portion  220  to hook with the upper surface  212 . Thus, the electrical element  22  is securely located on the insulated elastomer  21 . 
     In use, when an IC package is assembled to the insulative housing  1 , the IC package exerts a downward force on the upper contact portion  221  of the electrical element  22 . The S-shaped body portion  220  is deformed and the upper contact portion  221  presses the insulated elastomer  21 ,  21 ′ to be deformed. Thus, a good electrical connection is established between the IC package and the electrical elements  22  of the terminal units  2 ,  2 ′. When the IC package is removed, the spring of the insulated elastomer  21 ,  21 ′ makes the terminal units  2 ,  2 ′ come back to its original state. 
     While the present invention has been described with reference to preferred embodiments, the description of the invention is illustrative and is not to be construed as limiting the invention. Various of modifications to the present invention can be made to preferred embodiments by those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.