Patent Publication Number: US-2007111580-A1

Title: Contact for CPU socket

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to the art of electrical connectors, and particularly to an electrical connector for electrically connecting a CPU (Central Processing Unit) and a PCB (printed circuit board).  
      2. Description of the Prior Art  
      Electrical connectors are provided in a wide field to electrically connect two electronic components, such as a CPU package and a PCB.  
      An electrical connector for electrically connecting the CPU and the PCB comprises a housing and a plurality of terminals received in said housing. The housing includes a first surface for engaging with the CPU, a second surface opposite to the PCB and a number of terminal-receiving passageways running through the first and second surfaces. Each terminal comprises a base, a contact section and a soldering section extending from the base to outwardly of the first and second surfaces, respectively. When the soldering section of the terminal is attached to the corresponding soldering point of the PCB, the contact section comes to flexibly deform and slide over the pads of the CPU in the action of the CPU pressing the contact section to electrically connect.  
      In use, as the CPU is often exposed to the surroundings of atmosphere, a layer of oxidation and other feculence of the pads are easy to form on the surface of the pads. At the same time, the contact section of the terminal is attached to the pads of the CPU in the width direction of the whole contact section such that contact friction is poor and the ability of removing the feculence is deficient.  
      Thus, there is a need to provide an electrical connector for electrically connecting the CPU and the PCB to overcome the above-mentioned problems.  
     SUMMARY OF THE INVENTION  
      Accordingly, an object of the present invention is to provide an electrical connector to improve the capability of transmission between the CPU and the PCB.  
      To fulfill the above-mentioned object, an electrical connector for electrically connecting the CPU with a plurality of conductive pads and the PCB in accordance with a preferred embodiment of the present invention comprises an insulative housing and a plurality of terminals received in said housing. The housing includes a first surface for engaging with the CPU, a second surface opposite to the PCB, and a plurality of terminal-receiving passageways running through the first and second surface. Each terminal comprises a base extending along each passageway, an elastic arm extending from the base towards the CPU, and a soldering section integrally attached to the PCB. A contact section is located near the end of the elastic arm of the terminal and a contact portion protrudes from a middle of the contact section to engage the pads of the CPU.  
      That the middle of the contact section defines a contact portion and the terminal is attached to the pads of the CPU only by said contact portion can reduce the contact area between terminals and conductive pads and thus increase the feculence removal efficiency. 
    
    
      Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which:  
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an exploded, perspective view of an electrical connector in accordance with a preferred embodiment of the present invention;  
       FIG. 2  is an exploded, isometric view of a terminal of the electrical connector;  
       FIG. 3  is an enlarged view of a circled part  2  in  FIG. 2 ;  
       FIG. 4  is a cross-sectional view taken along line  1 - 1  in  FIG. 1 , with the contact section of the terminals unconnected to the pads of the CPU;  
       FIG. 5  is similar to  FIG. 4 , but the contact section of the terminal has been connected to the pad of the CPU completely. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION  
      Reference will now be made to the drawings to describe the present invention in detail.  
       FIG. 1  is an exploded, isometric view of an electrical connector  10  for electrically connecting the CPU  40  and the PCB  50  in accordance with the preferred embodiment of the present invention. The electrical connector  10  comprises an insulative housing  20  and a plurality of terminals  30  received in said housing  20 .  
      The housing  20  comprises a first surface  202  for engaging with the CPU  40 , a second surface  206  opposite to the PCB  50 , and a plurality of terminal-receiving passageways  204  aligned as a matrix and extending through the first and second surfaces  202 ,  204 . Each passageway  204  includes a first elongate cavity  2042  and a second cavity  2046  vertical to the first cavity  2042 . A slant  2044  connects the first and second surfaces  2042 ,  2046 .  
      Each terminal  30  includes a flatten base  300  with a number of barbs  3002  in the two opposite lateral side thereof for interferential engagement with the first cavity  2042  of the passageway  204 , a soldering section  304  extending from a bottom edge of the base  300 , and an elastic arm  302  extending curvedly from a top edge of the base  300 . The elastic arm  302  has a contact section  306  near the free end thereof. And a contact portion  308  protrudes from the middle of the contact section  306  by punching a respective chamfer  310  on either side thereof so as to meet the pads  400  of the CPU  40 . The contact section  306  connects to the pads  400  of the CPU  40  only by the contact portion  308  in order to reduce the contact area between the terminal  30  and the pad  400  when terminals  30  are attached to the pads  400 .  
      During mounting the terminals  30  onto the housing  20 , the terminals  30  are assembled with corresponding passageways  204  from below. The base  300  is retained in the first cavity  2042  and engaged interferentially with the sidewalls thereof by the barbs  3002 . And the elastic arm  302  extends from the slant  2044  to outwardly of the second cavity  2046 . After assembling, the contact section  306  of the terminal  30  extends outwardly of the first surface  202  of the housing  20  and the soldering section  304  extends outwardly of the second surface  206 .  
      In the mounting process, the soldering section  304  of the terminal  30  is connected to the soldering point  500  of the PCB  50  by a solder ball  3040  and the contact portion  308  of the elastic arm  302  extends outwardly of the first surface  202 . At the beginning of assembling the CPU  40  on the electrical connector  10 , the conductive pads  400  of the CPU  40  is placed on the contact section  306  of the terminal  30 . With CPU  40  pressing the housing  20  by the action of an external force, the conductive pad  400  of the CPU  40  presses the contact section  306  till the elastic arm  302  of the terminal  30  becomes deformed. The terminal  30  does not slide immediately relative to the pad  400  of the CPU  40  and remove the oxidation layer and the feculence of the pad  400  until the force of pressing overcomes the frictional force between the contact portion  308  and the conductive pad  400  thereof in order to provide a better electrical connection.  
      In the course of connection between the terminals  30  and the conductive pads  400 , the contact area between the terminal  30  and the pad  400  is reduced and the friction therebetween is increased and the oxidation layer and the feculence of the pads  400  is removed so that the contact portion  308  of the terminal  30  mutually connects with the pads  400  of the CPU  40  and the other portion of the contact section  306  is unconnected therewith. At the same time it can insure there is a reliable electrical connection between the CPU  40  and the terminal  30 .  
      Although the present invention has been described with reference to particular embodiments, it is not to be construed as being limited thereto. Various alterations and modifications can be made to the embodiments without in any way departing from the scope or spirit of the present invention as defined in the appended claims.