Abstract:
A contact of an electrical connector includes an upper section for engaging a pin of a central processing unit module, a lower section retained in a bore defined in a housing of the connector with a tail section extending therefrom for being electrically connected to a circuit board and a plurality of spaced connecting sections, serving as signal transmission channels, arranged between the upper and lower sections and electrically connected thereto to serve as electrical current channels. By increasing the number of the connecting sections, the total cross-sectional area of the electrical channels is increased which effectively reduces the inductance thereof.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention generally relates to a contact of an electrical connector, and in particular to a contact of a socket connector for retaining a semiconductor device, such as a central processing unit (CPU) module on a circuit board. 
     2. The Prior Art 
     Socket connectors for retaining and electrically connecting a CPU module to a circuit board are known in the art. A socket connector comprises an insulative housing defining an array of bore therein for receiving and retaining conductive contacts. Each contact has a body portion from which a tail and a mating section extend in opposite directions. The body forms an electrical channel between the mating section and the tail. The tail extends beyond a lower face of the housing for being received in a corresponding pin opening defined in the circuit board. The mating section engages with a corresponding conductive terminal extending from the CPU module to establish electrical connection between the CPU module and the circuit. 
     With the increase of the operational frequency of CPUs, the contacts of the socket connector are subject to severe requirement in electrical properties, among which impedance, especially inductance, of the contact is one of the major problems to be addressed. The body of he contacts of the conventional socket connectors, such as those disclosed in the above mentioned prior art, forms a single signal transmission channel having a limited cross-sectional area thereby leading to difficulty in reducing inductance. 
     It is thus desired to provide a contact structure which overcomes the above problem encountered in high frequency operation of the CPUs. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the present invention is to provide a contact for a socket connector having reduced impedance. 
     Another object of the present invention is to provide a contact for a socket connector having an increased cross-sectional area for reducing the inductance thereof. 
     A further object of the present invention is to provide a contact for a socket connector having a body forming at least two spaced signal transmission channels thereby effectively increasing the cross-sectional area thereof and reducing the inductance. 
     To achieve the above objects, a contact of a socket connector in accordance with the present invention comprises an upper section for engaging a pin of a central processing unit module, a lower section retained in a bore defined in a housing of the connector with a tail section extending therefrom for being electrically connected to a circuit board and a plurality of spaced connecting sections, serving as signal transmission channels, arranged between the upper and lower sections and electrically connected thereto to serve as electrical current channels. By increasing the number of the connecting sections, the total cross-sectional area of the electrical channels is increased which effectively reduces the inductance thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be apparent to those skilled in the art by reading the following description of preferred embodiments thereof, with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a contact in accordance with a first embodiment of the present invention; 
     FIG. 2 is a perspective view of a contact in accordance with a second embodiment of the present invention; 
     FIG. 3 is a perspective view of a contact in accordance with a third embodiment of the present invention; and 
     FIG. 4 is a perspective view of a contact in accordance with a fourth embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings and in particular to FIG. 1, a contact of an electrical connector constructed in accordance with a first embodiment of the present invention, generally designated with reference numeral  100 , comprises a lower, retention section  102  and an upper, mating section  104  connected to the retention section  102  by at least two spaced connecting sections  106  arranged therebetween. A tail section  108  extends from the lower section  102  in a direction opposite the upper section  104 . 
     The contact  100  is received in a corresponding bore defined in a connector housing (not shown) and the retention section  102  is retained in the bore with the tail section  104  extending beyond a bottom surface of the housing for being mounted to a circuit board (not shown). A through hole technique may be used to fix the tail section  108  of the contact  100  to the circuit board wherein a pin opening is defined in the circuit board into which the tail section  108  is inserted and then soldered. Alternatively, a surface mount technology may be applied to solder the tail section  108  to the circuit board. 
     The mating section  104  forms an inclined surface  110  for guiding the engagement of a corresponding pin of a central processing unit (CPU) module (not shown) received in the bore of the connector housing with the contact  100 . 
     In accordance with the present invention, at least two connecting sections  106  are formed between and electrically connect the upper section  104  to the lower section  106  for establishing electrical connection between the CPU module and the circuit board. The two connecting sections  106  forms two electrical channels or signal transmission channels between the upper and lower sections  104 ,  102 . The two channels, as compared with the conventional one channel structure, provides a large cross-sectional area through which electrical current flows between the upper and lower sections  104 ,  102 . By the large cross-sectional area, the overall inductance of the electrical channels between the upper and lower sections  104 ,  102  is effectively reduced. 
     FIG. 2 of the attached drawings shows a contact, designated by reference numeral  200 , in accordance with a second embodiment of the present invention. The contact  200  comprises a lower, retention section  202  and an upper, mating section  204  connected to each other by three spaced connecting sections  206  arranged therebetween. A tail section  208  extends from the lower section  202  for being electrically connected to a circuit board (not shown). An inclination  210  is formed on the upper section  204  for facilitating engagement between the contact  200  and a corresponding pin of a CPU module (not shown). 
     As compared to the first embodiment discussed with reference to FIG. 1, the three connecting sections  206  of the contact  200  provide an even larger total cross-sectional area through which electrical current flows between the upper and lower sections  204 ,  202 . Thus, the overall inductance between the upper and lower sections  204 ,  202  is effectively reduced. 
     FIG. 3 shows a contact, designated by reference numeral  300 , in accordance with a third embodiment of the present invention. The contact  300  comprises a lower, retention section  302  and an upper, mating section  304  connected to each other by two spaced connecting sections  306  arranged therebetween. A tail section  308  extends from the lower section  302  for being electrically connected to a circuit board (not shown). An arcuate recess  310  is formed in the upper section  304  for receiving a corresponding pin of a CPU module (not shown) thereby forming electrical engagement therebetween. The connecting sections  306  are tapering from the lower section  302  toward the upper section  304  whereby a space between the connecting sections  306  is substantially triangular. 
     As discussed previously, the two connecting sections  306  of the contact  300  provide a large total cross-sectional area through which electrical current flows between the upper and lower sections  304 ,  302  whereby the overall inductance between the upper and lower sections  304 ,  302  is effectively reduced. 
     FIG. 4 shows a contact, designated by reference numeral  400 , in accordance with a fourth embodiment of the present invention. The contact  400  comprises a lower section  402  and an upper section  404  connected to each other by three spaced connecting sections, including a central connecting section  406 ′ and two side connecting sections  406 . A tail section  408  extends from the lower section  402  for being electrically connected to a circuit board (not shown). An arcuate recess  410  is formed in the upper section  404  for receiving a corresponding pin of a CPU module (not shown) thereby forming electrical engagement therebetween. The two side connecting sections  406  are fixedly connected to the upper and lower sections  404 ,  402 , while the central connecting section  406 ′ has a lower end fixedly connected to the lower section  402  and an upper end separated from the upper section  404  with a gap  412  therebetween. The gap  412  is such that when the pin of the CPU module is received in the recess  410 , the upper section  404  is moved due to resilient deformation of the side connecting sections  406  thereby contacting the upper end of the central connecting section  406 ′. Thus, three electrical channels or signal transmission channels are formed between the upper and lower sections  404 ,  402  when the contact  400  engages the pin of the CPU module. 
     As discussed previously, the three connecting sections  406 ,  406 ′ of the contact  400  provide a large total cross-sectional area through which electrical current flows between the upper and lower sections  404 ,  402  whereby the overall inductance between the upper and lower sections  404 ,  402  is effectively reduced. 
     It can be noted that by using plural parallel connection sections with a space(slot) between every adjacent two connection sections thereof, the invention may not only achieve the greater cross-section area for lowering the contact resistance of the individual contact, but also soften the contact for compliance with the normal force requirement of the contact with regard to the CPU pin, relative to the similar cross-section area without any space(slot) thereof. Moreover, the spaces(slots) result in greater amount of surface area of the contact due to the formed surface area surrounding each space(slot), which may affect the impedance in compliance with the electrical requirement. FIG. 4 further shows the two-step engagement arrangement between the contact and the CPU pin wherein the upper section  404  of the contact  400  projects laterally beyond the tip of the obliquely upwardly extending central connection section  406 ′. Thus, as mentioned before, the horizontally moved CPU pin will first engage the upper section  404  and then contact the tip of the central connection section  406 ′, thus efficiently lowering the initial abutment force between the contact  400  and the CPU pin for the mechanical benefit while stilling keeping the optimal cross-section area and the greater surface area of the contact for the electrical benefit. 
     Although the present invention has been described with reference to the preferred embodiments, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.