Patent Publication Number: US-6666693-B2

Title: Surface-mounted right-angle electrical connector

Description:
FIELD OF THE INVENTION 
     The present invention relates to electrical connectors, and more particularly to surface-mounted, right-angle electrical connectors. 
     BACKGROUND OF THE INVENTION 
     FIG. 6 depicts a conventional right-angle electrical connector  100 . Other examples of conventional right-angle electrical connectors can be found, for example, in U.S. Pat. Nos. 6,183,301 and 6,083,047. 
     The electrical connector  100  comprises a plurality of plate members  102  disposed in a side-by-side arrangement within a housing (the housing is not shown in FIG. 6, for clarity). A plurality of conducting members  120  and ground members  121  disposed within grooves formed in the plate members  102 . Each conducting member  120  has a mating pin  122  and a contact portion  124  disposed at respective first and second ends thereof. Each ground member  121  includes a mating pin  126  and a contact portion  128  disposed at respective first and second ends thereof. The mating pins  122 ,  126  each extend away from a forward surface  102   a  of the plate member  102 , in substantially the horizontal (“x”) direction. The contact portions  124 ,  128  each extend away from a lower surface  102   b  of the plate member  102 , in substantially the vertical (“y”) direction. 
     The electrical connector  100  is adapted to be mounted on a circuit substrate such as a printed wireboard (PWB)  130 . The contact portions  124 ,  128  are adapted to be inserted into through holes  131  in the PWB  130 . The contact portions  124 ,  128  are then soldered to electrical traces within the PWB  130 , thereby establishing electrical contact between the electrical connector  100  and the PWB  130 . 
     The contact portions  124 ,  128  extend below the mounting surface on the PWB  19 . Surface-mounted electrical connectors, by contrast, are typically soldered directly to electrical traces on a surface of a circuit substrate such as the PWB  19 . In other words, a surface-mounted electrical connector does not extend below the mounting surface on the circuit substrate. Hence, surface-mounted electrical connectors usually require less space within an electronic device than other types of electrical connectors of similar capabilities. This feature is particularly advantageous in light of the ongoing drive to reduce the size of electronic equipment, and to add additional functions to such equipment. 
     Applicants have found that surface mounting, although suitable for use with right-angle connectors, has certain limitations and disadvantages when used in such applications. In particular, the forces needed to restrain right-angle connectors laterally, i.e., parallel to the mounting surface, are difficult to achieve with a surface-mount configuration. (Lateral restraint in a conventional right-angle electrical connector such as the electrical connector  100  is achieved, at least in part, by interference between the contact portions  124 ,  128  and the circuit substrate upon which the connector  100  is mounted.) 
     Lateral restraint in a surface-mounted right-angle electrical connector can be achieved by placing bumps or projections on the lower surface of one or more of the plate members thereof, and securing the bumps or projections to a mounting surface of a circuit substrate. Co-planarity among the bumps or projections on different plate members, however, is generally difficult to achieve, thus limiting the degree of lateral restraint achievable using this mounting arrangement. Furthermore, precision-placement of the electrical connector on the mounting surface is usually difficult to achieve when the connector is being fixed to the circuit substrate. Hence, surface-mounted right-angle electrical connectors are not typically configured for surface mounting. 
     An ongoing need therefore exists for a surface-mounted, right-angle electrical connector that can be effectively restrained in the lateral direction, and that can be precisely positioned on a mounting surface of a circuit substrate. 
     SUMMARY OF THE INVENTION 
     A presently-preferred electrical connector comprises an electrically insulative base member having a first surface, a substantially planar second surface, and a plurality of stud members projecting from the second surface. The base member has a plurality of through holes formed therein. The through holes each extend from the first surface to a respective stud member. At least a portion of each of the stud members is coated with an electrically conductive material. The electrical connector also comprises an electrically-insulative plate member mounted on the base member, and a conducting member. The conducting member comprises a lead portion at least partially disposed within the plate member, and a contact portion at least partially disposed within the stud member. 
     A presently-preferred right-angle electrical connector comprises a plate member having a first and a substantially perpendicular second surface, and a conducting member. The conducting member is at least partially disposed within the plate member and comprises a contact portion extending away from the second surface, and a mating pin extending away from the first surface. The electrical connector also comprises an electrically-insulative base member comprising a stud member and a main portion having a first surface and a substantially planar second surface. The first surface of the main portion is adapted to receive at least a portion of the plate member, and the stud member projects from the second surface of the main portion and is adapted to be mounted on a circuit substrate. A passage is formed within the base member and extends through the main portion and the stud member, and the conducting member is at least partially disposed within the passage. The stud member is at least partially covered with a conductive coating adapted to establish electrical contact between the contact portion and an electrical connection point on the circuit substrate. 
     Another presently-preferred electrical connector comprises a plurality of conducting members each comprising a contact portion and a lead portion electrically coupled to the contact portion, and a plurality of plate members disposed within the housing. Each of the plate members has a plurality of grooves formed therein for receiving the lead portions. The electrical connector also comprises a base member having a plurality of grooves formed in a first surface thereof for receiving and retaining the plate members, and a plurality of stud members projecting from a second surface thereof and being adapted to mount on a circuit substrate. The base member receives each of the contact portions in respective passages formed therein and extending through the stud members. The contact portions are adapted to be electrically coupled to the circuit substrate by a conductive coating disposed on at least a portion of each of the stud members. 
     Another presently-preferred electrical connector comprises a plurality of conducting members each comprising a contact portion and a lead portion electrically coupled to the contact portion. The electrical connector also comprises a plurality of electrically insulative plate members each having a first surface, a substantially perpendicular second surface, and a plurality of stud members projecting from the second surface. The stud members are at least partially covered by an electrically-conductive coating and are adapted to be mounted on a circuit substrate. The conducting members each extend between one of the first surfaces and one of the stud members. Each of the contact portions is at least partially disposed within a respective one of the stud members and is adapted to be electrically coupled to the circuit substrate by the conductive coating. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of illustrating the invention, the drawings show an embodiment that is presently preferred. The invention is not limited, however, to the specific instrumentalities disclosed in the drawings. In the drawings: 
     FIG. 1 is a side view of a presently-preferred right-angle electrical connector; 
     FIG. 2 is a partially-exploded side view of a connector module and a base member of the electrical connector shown in FIG. 1; 
     FIG. 3 is a partially-exploded front view of the connector module and base member shown in FIG. 2, taken through the line “A—A” of FIG. 1; 
     FIG. 4 is a magnified view of the area designated “B” in FIG. 3, with the connector module and the base member shown in FIGS. 2 and 3 in an assembled state; 
     FIG. 5 is a side view of an alternative embodiment of the connector module shown in FIG. 2; and 
     FIG. 6 is a side view of a conventional right-angle electrical connector. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIGS. 1-4 depict a presently-preferred surface-mounted right-angle electrical connector  10 . Each of the figures referred to throughout the specification is referenced to a common coordinate system  8  depicted therein. The electrical connector  10  is adapted to be mounted on a circuit substrate such as a printed wireboard (PWB)  19 . The electrical connector  10  adapted to mate with a second electrical connector, another circuit substrate, or a backplane (not shown). The electrical connector  10  is described in detail herein for exemplary purposes only, as the invention can be applied to virtually any type of right-angle connector. Certain features of the electrical connector  10  are also described in a co-pending application filed on Nov. 20, 2001 and titled “Pin-Grid-Array Electrical Connector,” which is incorporated herein by reference in its entirety. 
     The electrical connector  10  comprises a base member  11 , a plurality of connector modules  12 , and a housing  13 . The housing includes a main portion  13   a  and a forward portion  13   b  (see FIG.  1 ). The base member  11  is adapted to be mounted on a surface of the PWB  19 , as explained in detail below. The connector modules  12  are substantially enclosed by the housing  13 , and are mounted on the base member  11 . 
     Each connector module  12  comprises a plate member  17 , a plurality of signal conducting members  20 , and a plurality of ground conducting members  21  (see FIG.  2 ). Each signal conducting member  20  comprises a mating pin  24 , a lead portion  26 , and a contact portion  28 . A first end of the lead portion  26  is mechanically and electrically coupled to the contact portion  28 , and an opposing second end of the lead portion  26  is mechanically and electrically coupled to the mating pin  24 . This arrangement forms an electrical path between the mating pin  24  and the contact portion  28 . 
     Each of the contact portions  28  preferably has a substantially rectangular cross-section. The lead portions  26  each include one or more bends that cause the mating pin  24  and the contact portion  28  to extend in substantially perpendicular directions, i.e., the mating pin  24  extends substantially in the “x” direction, and the contact portion  28  extends substantially in the “y” direction (see FIG.  2 ). 
     Each ground conducting member  21  comprises a lead portion  30  (see FIG.  2 ). A first end of each lead portion  30  is mechanically and electrically coupled to a contact portion  32 . An opposing second end of each lead portion  30  is mechanically coupled to a mating pin  34 . This arrangement electrically couples the contact portion  32  and the mating pin  34 . Each of the contact portions  32  preferably has a substantially rectangular cross-section (other cross-sectional shapes, e.g., circular or conical, can also be used). The lead portions  30  each include one or more bends that cause the mating pins  34  and the contact portions  32  to extend in substantially perpendicular directions, i.e., the mating pins  34  extend substantially in the “x” direction, and the contact portions  32  extend substantially in the “y” direction.” 
     Each plate member  17  is formed from an electrically insulative material such as plastic. The plate members  17  each have a substantially planar forward surface  17   a  and a substantially planar lower surface  17   b  (see FIG.  2 ). The forward surface  17   a  and the lower surface  17   b  are substantially perpendicular. The plate member  17  has a plurality of grooves  35  formed therein (see FIG. 3; the grooves  35  are not depicted in FIG. 2, for clarity). The grooves  35  extend between the forward surface  17   a  and the lower surface  17   b , and receive the respective lead portions  26 ,  30  of the conducting members  20  and the ground members  30 . This arrangement causes the mating pins  24 ,  34  to extend away from the forward surface  17   a  of the plate member  17 ; the contact portions  28 ,  32  likewise extend away from the lower surface  17   b  of the plate member  17 . Alternative embodiments of the plate members  17  may accommodate more or less than the six conducting members  20  and six ground conducting members  21  positioned within each plate member  17 . 
     It should be noted that directional terms such as “upper,” “lower,” etc., are used with reference to the component orientations depicted in FIGS. 1-4; these terms are used for illustrative purposes only and, unless expressly stated otherwise, are not intended to limit the scope of the appended claims. 
     The exemplary electrical connector  10  includes six of the connector modules  12  disposed in a side-by-side arrangement within the housing  13 . In other words, the connector modules  12  are positioned so that the forward surfaces  17   a  of the plate members  17  are substantially co-planar, and the lower surfaces  17   b  of the plate members  17  are also substantially co-planar. The contact portions  32 ,  26  each extend below the main portion  13   a  of the housing  13 . The significance of this feature is discussed below. 
     The forward portion  13   b  of the housing  13  encloses the mating pins  24 ,  34  (see FIG.  1 ). The mating pins  24 ,  34  are each adapted to engage a respective a female receptacle on another connector, a circuit substrate (other than the PWB  19 ), or a backplane. 
     The connector modules  12  are mechanically and electrically coupled to the PWB  19  by way of the base member  11 . The base member  11  comprises a main portion  18 . The main portion  18  has an upper surface  18   a  that partially receives the plate members  17 , and a substantially planar second surface  18   b . The base member  11  further comprises a plurality of stud members  22  projecting from the second surface  18   b . The stud members  22  and the main portion  18  are formed from an insulative material such a plastic, and most preferably are formed from liquid crystal polymer (LCP). The stud members  22  and the main portion  18  are preferably formed on a unitary basis. Each stud member  22  has an inner, or recessed surface portion  22   a  that defines a recess  40  (see FIGS.  3  and  4 ). The significance of this feature is explained below. 
     The upper surface  18   a  of the base member  18  defines a plurality of slots  33  (see FIG.  3 ). The slots  33  each extend substantially in the longitudinal (“x”) direction, along substantially an entire length of the base member  18 . A bottom of each slot  33  is defined by a surface portion  18   a   1  of the upper surface  18   a    
     Each of the slots  33  is sized to partially receive a respective one of the plate members  17 . In particular, each of the slots  33  has a width (“z” dimension) and a length (“x” dimension) approximately equal to a respective width and length of each plate member  17 . Each slot  33  is thus adapted to receive and securely engage a bottom portion of a respective plate member  17  by way of a press fit. In other words, a bottom portion of each plate member  17  is pressed into a respective one of the slots  33  so that the bottom surface  17   b  of the plate member  17  abuts the surface portion  18   a   1  of the base member  11 , thereby securing the plate member  17  to the base member  11 . (Other suitable means of securing the plate members  17  to the base member  11  can be used instead of a press fit.) 
     A plurality of through holes  32  are formed in the base member  11  (see FIG.  3 ). Each through hole  32  is defined by a respective surface portion  18   c  in the main portion  18 . 
     The through holes  32  each extend from the surface portion  18   a   1  to a respective stud member  22 . Each through hole  32  adjoins a respective recess  40 . Each corresponding through hole  32  and recess  40  form a passage  42  that extends through the main portion  18  and the respective stud member  22 . The passage  42  is adapted to receive at least a portion of a contact portion  32 ,  26 . In other words, the contact portions  32 ,  36  are each substantially aligned with, and extend into a respective passage  42  when the plate members  17  are positioned on the base member  11 . Further details concerning the passages  42  are presented below. 
     The surface portions  18   c  and the stud members  22  are at least partially covered with a conductive coating  44 . (The thickness of the conductive coating is exaggerated in the figures, for clarity.) The conductive coating  44  is a metallized layer that establishes electrical contact between the contact portions  32 ,  36  and the PWB  19 , as explained in detail below. The coating  44  is preferably formed from copper (Cu), nickel (Ni), and tin (Sn). The coating  44  is applied by activating the second surface  18   b  of the main portion  18  and a lower end of the surface portion  18   c  with electroless CU. The recessed surface portion  22   a  of the stud member  22  are also activated with the electroless CU. A  20 - 25 -micron layer of electrolytic CU, a  4 - 6 -micron layer of electrolytic Ni, and a  4 - 6  micron layer of electrolytic Sn are then sequentially applied to the activated areas. 
     A substantial portion of the Sn layer located on the second surface  17   b  is subsequently removed by laser oblation, and the underling layers of Cu and Ni are removed by chemical etching. The coating  44  that remains after this process forms a substantially contiguous metallized layer on and immediately surrounding each stud member  22 . In particular, the coating  44  associated with each stud member  22  covers an outer surface  22   b  and the recessed surface portion  22   a  of the stud member  22 , a portion of the second surface  18   b  immediately adjacent the outer surface  22   b , and the lower end of each surface portion  18   c.    
     It should be noted that specific details relating to the composition and application of the coating  44  are presented for exemplary purposes only; the coating  44  can be formed from virtually any type of suitable conductive material applied in any conventional manner. 
     The passages  42  are each adapted to receive at least a portion of one of the contact portions  32 ,  36 , as noted above. A minimal clearance, e.g., 0.001 inch, preferably exists between each signal or contact portion  32 ,  36  and the coating  44  when the contact portions  32 ,  36  are positioned within the passages  42 . 
     The PWB  19  includes a plurality of electrical traces that each terminate in a respective electrical connection point  19   a  (see FIG.  4 ). The electrical connector  10  is mechanically and electrically coupled to the PWB  19  by a mass soldering process, e.g., wave soldering, that forms a solder joint  23  between each stud member  22  and a corresponding electrical connection point  19   a  (see FIG. 4; the solder joints  23  are not depicted in FIG. 1 or  3 , for clarity). 
     The base member  11  preferably includes at least one stud-member support  22   c . The stud-member support  22   c  does not have a signal or contact portion  32 ,  36  disposed therein. 
     The stud-member support  22   c  functions a guide for precisely positioning the electrical connector  10  on the PWB  19  as the electrical connector  10  is secured to the PWB  19 . 
     The mechanical and electrical connections between the electrical connector  10  and the PWB  19  are facilitated by the conductive coating  44 . More specifically, the solder joints  23  securely bond the electrical connection points  19   a  to the conductive coating  44  on the respective stud members  22 , thereby securing the electrical connector  10  to the PWB  19 . 
     Furthermore, the conductive coating  44 , in conjunction with the solder joints  23 , forms an electrically-conductive path between the electrical connection points  19   a  and the respective contact portions  28 ,  32 . 
     The electrical connector  10  provides substantial advantages in relation to conventional surface-mounted right-angle connectors. For example, the electrical connector  10  provides the advantages of surface-mounted connectors, e.g., compact size, while avoiding the difficulties usually associated with precisely positioning such connectors on a mounting surface. In particular, the stud-member supports  22   c  permit the electrical connector  10  to be precisely aligned with a predetermined position on the PWB  19  when the electrical connector  10  is installed on the PWB  19 . This feature facilitates optimal electrical contact between the electrical connection points  19   a  on the PWB  19 , and the respective conducting members  20 ,  21  of the electrical connector  10 . In addition, forming the stud members  22  as part of a unitary base member  11  facilitates a relatively high degree of co-planarity among the stud members  22 , further optimizing the electrical contact between the electrical connection points  19   a  and the conducting members  20 ,  21 . 
     It is to be understood that even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of the parts, within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. For example, alternative configurations for the stud members  22  are set forth in the co-pending application filed on Nov. 20, 2001 and titled “Pin-Grid-Array Electrical Connector” which, as previously noted, is incorporated herein by reference in its entirety. Furthermore, the mating pins  24 ,  34  of the electrical connector  10  can be replaced with female receptacles, i.e., the electrical connector  10  can be adapted to mate with a complementary pin connector. 
     FIG. 5 depicts connector module  50 . The connector module  50  represents an alternative embodiment of the connector module  12 . Components of the connector module  50  that are substantially identical to those of the connector module  12  are denoted by common reference numerals. The connector module  50  comprises a plate member  52  having stud members  22  formed on a lower surface  52   a  thereof. The connector module  52  is thus adapted to mount directly on a circuit substrate such as the PWB  19 . In other words, the connector module  50  mounts on the PWB  19  without the use of a base member such as the base member  11  of the electrical connector  10 .