Abstract:
An electrical receptacle connector is provided having a housing with a front face that includes an opening therein. The opening is configured to receive a plug connector. The receptacle connector further includes a ground shield having a face plate with a hole through the face plate. The face plate covers the front face of the housing such that the hole in the face plate aligns with the opening in the front face of the housing. A ground finger is separately mounted to at least one of the ground shield and the housing with a first end of the ground finger extending into the opening in the housing.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention generally relates to electrical connectors for use with high speed serial data, and more particularly, to connector assemblies for transferring high speed serial data from a cable to a circuit board.  
           [0002]    In the past, electrical cable assemblies have been proposed for connecting electrical cables to circuit boards. Conventional cable assemblies have been provided with an equalizer circuit board within the connector for performing signal conditioning. Performing signal conditioning within a circuit in the connector assembly, reduces the time required to incorporate signal conditioning circuit elements with a cable assembly and reduces the time required for connection of the circuit elements with the electrical contacts and the cable conductors. One example of a conventional cable assembly with an equalizer board is described in U.S. Pat. No. 5,766,027, commonly owned with the present application, which is incorporated herein in its entirety by reference.  
           [0003]    Conventional high speed serial data connectors (HSSDC) comprise a plug and receptacle combination interconnected through contact fingers. HSSDC connectors form a grounding plane surrounding the adjoining surfaces of the receptacle and plug in order to afford electromagnetic interference (EMI) shielding around the contact fingers forming the high speed serial data connection between the plug and receptacle. In conventional HSSDC connectors, EMI shielding is also provided by surrounding the receptacle housing with a ground shield. The ground shield is formed integrally with a plurality of grounding beams on the top, bottom and side walls of the receptacle housing. The ground shield is also formed with grounding beams that are J-shaped integral extensions of the ground shield and are bent to project into the opening of the receptacle. The J-shaped ground beams are biased inward to maintain an electrical connection with the plug once inserted.  
           [0004]    U.S. Pat. No. 6,276,943 discloses a conventional HSSDC receptacle connector. The &#39;943 patent illustrates a shield 48 that includes ground tabs 58 which extend into an opening 41 to engage a plug connector shield. The ground tabs 58 are distributed about the interior surfaces of the opening 41.  
           [0005]    However, the arrangement of the &#39;943 patent has met with certain limitations. In particular, the degree to which EMI shielding is achieved is in part dependent upon the number of ground tabs and the positions of the ground tabs about the opening. In the &#39;943 patent, the top and bottom ground tabs are located along the top and bottom edges of the opening near the center of the opening which is somewhat remote from the side ground tabs that are located along the side edges of the opening. The wide separation between side ground tabs and the top and bottom ground tabs of the &#39;943 patent is in part necessitated by the fact that the shield is punched from a common, flat sheet of material as all of the side, top and bottom ground tabs. Hence, ground tabs along adjacent edges of the opening (e.g., top and side, or bottom and side) must be distanced sufficiently from one another to avoid overlap in the stamping process. By way of example, the bottom ground tabs must be located a distance from the side edges that is at least as long as the length of the bottom and side ground tabs. Otherwise the outer tips of the side ground tabs would be cut off by the stamp forming the bottom ground tabs, and vice versa.  
           [0006]    As data rates continue to increase, the need exists for added EMI shielding about the interface between the plug and receptacle connectors. The shielding capability of the design proposed in the &#39;943 patent is limited by the stamping process and the configuration and geometry of the ground tabs formed with the shield.  
           [0007]    A need exists for an improved HSSDC receptacle connector that affords added EMI shielding at the interface between the plug and receptacle connectors.  
           [0008]    Moreover, at high data rates, the ground tabs become more inductive. The inductance of the ground tab increases as the ground tab becomes shorter and more narrow. The desire to limit inductance is balanced with the desire to maintain the elastic properties of the ground tab. As ground tabs are shortened and made wider, they become less elastic or spring-like. A need exists for a ground member that is highly elastic, yet exhibits low inductance properties.  
           [0009]    It is an object of certain embodiments of the present invention to meet the foregoing need and to overcome problems experienced heretofore.  
         BRIEF SUMMARY OF THE INVENTION  
         [0010]    An electrical receptacle connector is provided having a housing with a front face that includes an opening configured to receive a plug connector. The receptacle connector further includes a ground shield having a face plate with a hole through the face plate. The face plate covers the front face of the housing such that the hole in the face plate aligns with the opening in the front face of the housing. A ground finger is separately mounted to at least one of the ground shield and the housing with a first end of the ground finger extending into the opening in the housing to interconnect the plug and ground shield.  
           [0011]    Optionally, the ground finger may be provided with a body that is held between the outside of the housing and the ground shield. The body may include an intermediate portion that wraps about the front face of the housing, where the intermediate portion is sandwiched between the face plate of the ground shield and the front face of the housing.  
           [0012]    The ground shield may further include a ground beam formed integral with the face plate proximate an edge of the hole through the face plate. The ground finger and the ground beam extend along interior surfaces of adjacent interior walls of the opening in the housing. Optionally, the face plate may include side, top and bottom portions aligned in a common plane and surrounding the hole through the face plate. At least one of the side, top and bottom portions may hold the ground finger against the housing.  
           [0013]    In accordance with an alternative embodiment, an electrical receptacle connecter is provided having a housing with walls surrounding a plug reception chamber that opens onto a front face of the housing. A ground shield is provided over at least one of the walls and/or the front face. The ground shield is integrally formed with a ground beam that is bent to extend into the plug receptacle chamber. A ground finger is also provided that is separately attached to at least one of the walls, the front face and the ground shield. The ground finger extends into the chamber as well.  
           [0014]    Optionally, the ground beam and ground finger may be located along adjacent walls of the plug reception chamber. The ground finger and ground beam may be spaced apart from one another by a distance that is less than a length of the ground beam and/or ground finger, where the lengths of the ground beam and ground finger are measured from outer ends thereof to the hole through the ground shield.  
         BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS  
         [0015]    [0015]FIG. 1 illustrates a front view of a receptacle connecter formed in accordance with an embodiment of the present invention.  
           [0016]    [0016]FIG. 2 illustrates an isometric view of a receptacle connector formed in accordance with an embodiment of the present invention with the ground fingers removed.  
           [0017]    [0017]FIG. 3 illustrates an isometric view of a receptacle housing formed in accordance with an embodiment of the present invention with the ground fingers and ground shield removed.  
           [0018]    [0018]FIG. 4 illustrates an isometric view of a ground finger formed in accordance with an embodiment of the present invention.  
           [0019]    [0019]FIG. 5 illustrates a top sectional view taken along line  5 - 5  in FIG. 1 of the receptacle connector of FIG. 1.  
           [0020]    [0020]FIG. 6 illustrates a side sectional view taken along line  6 - 6  in FIG. 1 of the receptacle connector of FIG. 1. 
       
    
    
       [0021]    The foregoing summary, as well as the following detailed description of certain embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, certain embodiments. It should be understood, however, that the present invention is not limited to the arrangements and instrumentalities shown in the attached drawings.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0022]    [0022]FIG. 1 illustrates a receptacle connector  10  mounted in a die-cast bracket  12  that is configured to be joined through posts  14  to a panel of a chassis or other enclosure and to support the receptacle connector  10 . The receptacle connector  10  includes a ground shield  16  that surrounds at least a portion of a receptacle housing  18  (better shown in FIG. 3). The receptacle housing  18  includes a chamber  20  configured to receive a plug connector. The ground shield  16  includes a face plate  22  that has a hole  24  cut therethrough in alignment with the opening of the chamber  20  when the face plate  22  is mounted to the receptacle housing  18 . The hole  24  is bounded by a top edge  26 , a bottom edge  28  and side edges  30 . The top and bottom edges  26  and  28  are formed integrally with ground beams  32  that extend into the chamber  20 . The chamber  20  also receives separable ground fingers  34  along opposite sides thereof.  
         [0023]    [0023]FIG. 2 illustrates an isometric view of the receptacle connector  10  with the ground fingers  34  (FIG. 1) removed. As better shown in FIG. 2, the ground shield  16  includes side flanges  36  formed integrally with the face plate  22 . The side flanges  36  are bent rearward to enclose (at least partially) side walls  38  of the receptacle housing  18 . The ground shield  16  also includes top and bottom flanges  40  and  42  that are similarly formed integral with the face plate  22  and bent rearward to at least partially enclose the top and bottom walls  44  and  46  of the receptacle housing  18 . The face plate  22 , side flanges  36 , top flange  40  and bottom flange  42  afford a desired amount of EMI shielding to reduce attenuation of high-speed serial data signals.  
         [0024]    The side flanges  36  include ground arms  48  stamped therein and projecting outward to engage the bracket  12  (FIG. 1) once mounted. The side flanges  36  also include tabs  50  extending downward from the lower edges of the side flanges  36 . The tabs  50  are configured to be received in holes in a circuit board, where the holes are connected to ground traces in the circuit board. Optionally, the tabs  50  may be removed and the ground shield may be surface mounted to a circuit board or other structure. The top flange  40  also includes grounding arms  52  extending upward that are intended to engage the bracket  12 .  
         [0025]    The face plate  22  is generally composed of side portions  54 , a top portion  56  and a bottom portion  58  that include side, top and bottom edges  30 ,  26  and  28 , respectively, that collectively define the hole  24 . The top and bottom edges  26  and  28  are integrally formed with ground beams  32  that are bent to extend into the chamber  20 .  
         [0026]    [0026]FIG. 3 illustrates the receptacle housing  18  in more detail to better show the side walls  38 , top wall  44  and bottom wall  46 . The receptacle housing  18  also includes a front face  60  onto which the chamber  20  opens. The interior surfaces  39  of the side walls  38  include notches  62  that extend rearward from the front face  60 . The interior surfaces of the top and bottom walls  44  and  46  also include notches  64  configured to receive corresponding ground beams  32  (FIG. 2). The exterior surfaces of the side walls  38  include cavities  66  cut therein and extending rearward from the front face  60 . The cavities  66  are located on the exterior surface opposite to corresponding notches  62  provided on the interior surface  39  of the associated sidewall  38 . The notches  62  and cavities  66  are configured to receive ground fingers  34  (FIG. 1) as explained below in more detail.  
         [0027]    The side walls  38  also include ledges  68  cut inward and located remote from the front face  60 . The ledges  68  receive latching features on the ground shield  16  to retain the ground shield  16 . Optionally, the top wall  44  may include tabs  70  that extend upward to engage and assist in retaining the ground shield  16 .  
         [0028]    [0028]FIG. 4 illustrates an isometric view of a ground finger  34 . The ground finger  34  includes a body  72  that is formed integrally with ground beams  74  at an intermediate (bent) portion  76 . The body  72  includes barbs  78  on opposite edges thereof that are configured to be received securely by border edges of the cavity  66  (FIG. 3). The ground beams  74  are bent to form generally a U-shape with the body  72 . Once inserted, the body  72  is retained securely within the cavity  66 , while the intermediate portion  76  wraps around the front face  60  at the side walls  38  (FIG. 3). The ground beams  74  extend acutely into the chamber  20  through the notches  62 . The ground beams  74  are spaced apart by a distance D1 that may be varied to distribute the ground beams  74  along the interior surfaces of the side walls  38  as desired. Optionally, only one ground beam  74  may be provided or alternatively more than two ground beams may be formed integral with a single body  72 . The ground beams  74  have outer tips  80  that are spaced a distance D2 from the bent intermediate portion  76 . The distance D2 may be varied depending upon the depth of the chamber  20  and the positioning of shielding upon the plug connector. The ground beams  74  are tapered along their length to afford a wide base denoted W b  and a narrower tip denoted W t .  
         [0029]    The distance D2 is maintained sufficient to provide a cantilever spring design for the ground beams  74 . By maintaining a desired distance D2 with each ground beam  84 , the mechanical reliability is improved and the ground beams  84  remain fully elastic for a longer working life. The width W b  at the base of the ground beams  84  is maintained sufficient in order that the inductive properties of the ground finger  34  is reduced.  
         [0030]    [0030]FIG. 5 illustrates a top sectional view taken along line  5 - 5  of FIG. 1 of the receptacle connector  10  when mounted in the bracket  12 . The body  72  of each ground finger  34  is held within cavities  66 , and thus is only partially shown, while the bent intermediate portion  76  is pitched or sandwiched between the front face  60  at the sidewall  38  and the face plate  22  of the ground shield  16 . The ground beams  74  extend the distance D2 into the chamber  20 , where D2 is measured from the bent intermediate portion  76  (which corresponds to the position of the face plate  22  and ground face  60 ) to the outer tip  80 .  
         [0031]    When a plug connector is inserted, the ground beams  74  are deflected in the directions of arrow A and B which tend to bias the body  72  outward toward the side flanges  36  on the ground shield  18 . The side flanges  36  and the frictional engagement between barbs  78  (FIG. 4) and the edges of cavities  66  hold the bodies  72  in a desired position relative to the receptacle housing  18  as the ground beams  74  are deflected toward notches  62 .  
         [0032]    As shown in FIG. 5, a plurality of ground beams  32  may be provided along the interior surface of the bottom wall  46 . The ground beams  32  are spaced a distance D3 from the side edge  30  of the hole  24  in the face plate  22 . The ground beams  32  have outer tips  33  that extend a distance D4 from the face plate  22 . The distances D4 and D2 corresponding to the lengths of the ground beams  32  and ground fingers  34 , respectively, are longer than the spacing between the ground beams  32  and the side edges  30  of the hole  24  to afford a more dense configuration of grounding beams and fingers  32  and  34 , thereby improving the EMI shielding at the interface between the plug and receptacle.  
         [0033]    As shown in FIG. 5, the side flanges  36  include latching tips  37  that are formed on outer ends to engage securely the ledges  68  formed in the side walls  38 . In this manner, the ground shield  16  is securely retained against the front face  60  of the receptacle housing  18 .  
         [0034]    [0034]FIG. 6 illustrates a side sectional view taken along line  6 - 6  in FIG. 1 of the receptacle connector  10  while mounted in the bracket  12 . As shown in FIG. 6, the ground beams  32  are formed integrally at elbows  84  with the face plate  22 . The ground beams  32  are deflectable toward notches  64  in the top and bottom walls  44  and  46 . The ground fingers  34  are received in notches  62  in the sidewall  38 . The ground fingers  34  are spaced a distance D5 from the top and bottom edges  26  and  28  of the hole  24 . The distance D5 between the ground fingers  34  and the top and bottom edges  26  and  28  is less than the lengths D2 and D4 of the ground fingers  34  and ground beams  32 .  
         [0035]    [0035]FIG. 6 also illustrates a contact  90  held within chamber  20  and extending from a rear end  92  of the receptacle connector  10 . One or more rows of contacts  90  are configured to join with corresponding contacts in the plug connector when inserted into the chamber  20 .  
         [0036]    The ground fingers  34  are provided as separate and distinct components from the ground shield  16  to avoid the need to stamp, from the ground shield  16 , ground beams  32  along adjacent edges of the hole  24 . Optionally, the ground beams  32  may be formed integral with the side edges  30  of the hole  24 , while the separate ground fingers  34  may be provided proximate the top and bottom walls  44  and  46  of the receptacle housing  18 .  
         [0037]    The number of grounding beams and grounding fingers may be reduced or increased depending upon the data rate to be supported by the receptacle connector and EMI reduction desired.  
         [0038]    While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to, the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.