PATENT DOCUMENT

Publication Number: US-9445491-B2
Application Number: US-201414231372-A
Country: US
Kind Code: B2

Title: Overpass grounding spring and integrated component protection

Abstract:
The described embodiments relate generally to use of an electrically conductive member, such as a grounding spring, used to electrically ground components on a printed circuit board as well as provide mechanical protection to the components. More particularly, a method and apparatus for attaching a grounding spring to multiple locations on the printed circuit board are disclosed. In one embodiment, the grounding spring can act as both a ground and a mechanical protection element for other surface mounted components disposed on the printed circuit board.

Claims:
What is claimed is: 
     
       1. A single-piece multi-level grounding spring formed of an electrically conductive material and suitable for providing a ground to a circuit board having a top surface that includes a conductive pad and a component, the circuit board further comprising a bottom surface opposite the top surface, the circuit board further comprising an edge plate disposed on a lateral surface and operable to route a signal between the top and the bottom surface, the single-piece multi-level grounding spring comprising:
 a first portion extended laterally a first level, the first portion having a ground contact configured to electrically couple the circuit board with a chassis ground; 
 a second portion extended laterally from the first portion at a second level different than the first level and configured to electrically connect to the conductive pad; and 
 a third portion at a third level different than the first level and different from the second level, the third portion capable of covering the component; 
 wherein the third portion comprises an overpass portion extends to a joint permanently attached with the edge plate. 
 
     
     
       2. The single-piece multi-level grounding spring of  claim 1 , wherein a width of the overpass portion is sufficient to cover an entire surface of the component. 
     
     
       3. The single-piece multi-level grounding spring of  claim 2 , wherein the width of the overpass portion is sufficient to cover a surface of a second component of the circuit board, the second component different from the component. 
     
     
       4. The single-piece multi-level grounding spring of  claim 1 , further comprising a side shield coupled with the overpass portion, the side shield capable of shielding the component from radio frequency emission. 
     
     
       5. The single-piece multi-level grounding spring of  claim 4 , wherein the side shield is perpendicular with respect to the overpass portion. 
     
     
       6. The single-piece multi-level grounding spring of  claim 1 , wherein the first portion comprises an L-shaped configuration that includes the ground contact. 
     
     
       7. A method for electrically grounding a circuit board having a conductive pad and an edge plate and protecting a component on the circuit board using a single-piece grounding spring, the method comprising:
 forming a ground contact configured to couple the circuit board with a ground chassis; 
 forming a planar section extended laterally from the ground contact and elevated with respect to the ground contact and coupled with the circuit board at the conductive pad; and 
 forming an overpass portion extended laterally from the planar section and elevated with respect to the planar section, the overpass portion having a size sufficient to cover a surface of the component; and 
 forming a joint disposed between the planar section and the overpass portion, the joint configured to receive a force in response to a force provided to the ground contact, wherein the overpass portion extends to a second joint attached with the edge plate; 
 wherein the overpass portion and the second joint are permanently attached with the edge plate. 
 
     
     
       8. The method of  claim 7 , further comprising forming an L-shaped configuration that includes the ground contact. 
     
     
       9. The method of  claim 7 , wherein a width of the overpass portion is sufficient to cover an entire surface of the component. 
     
     
       10. The method of  claim 9 , wherein the width of the overpass portion is sufficient to cover a surface of a second component of the circuit board, the second component different from the component. 
     
     
       11. The method of  claim 7 , further comprising coupling a side shield with the overpass portion, the side shield capable of shielding the component from radio frequency emission. 
     
     
       12. The method of  claim 11 , wherein the side shield is perpendicular with respect to the overpass portion. 
     
     
       13. A connector assembly comprising a circuit board and a single-piece grounding spring, the circuit board configured to receive the single-piece grounding spring that includes a ground contact, a planar section, an overpass portion, and a joint, the circuit board comprising:
 a substrate comprising a first notch configured to receive a section of the single-piece grounding spring and allow the single-piece grounding spring to extend away from the substrate and carry the ground contact, the substrate further comprising a second notch opposite the first notch and configured to receive the joint of the single-piece grounding spring; 
 a solder pad disposed on the substrate, the solder pad electrically and mechanically coupling the planar portion of the single-piece grounding spring with the substrate; 
 a component electrically coupled with the substrate, the component overlaid by the overpass portion of the single-piece grounding spring when the single-piece grounding spring is coupled with the substrate at the first notch and the second notch; and 
 an edge plate electrically coupled with the single-piece grounding spring at the joint. 
 
     
     
       14. The circuit board of  claim 13 , wherein the edge plate is operable to route signals between a top surface and a bottom surface of the substrate. 
     
     
       15. The circuit board of  claim 13 , wherein the edge plate electrically and mechanically couples the single-piece grounding spring with the substrate. 
     
     
       16. The circuit board of  claim 13 , wherein the component includes a top surface that is entirely overlaid by the single-piece grounding spring. 
     
     
       17. The circuit board of  claim 13 , wherein the component is shielded from radio frequency emission from a side shield coupled with the overpass portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application claims the benefit of priority under 35 U.S.C §119(e) to U.S. Provisional Application No. 61/873,737, filed on Sep. 4, 2013, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to overpass grounding components on a printed circuit board. In particular, a method and apparatus for coupling a grounding spring to multiple locations on the printed circuit board are disclosed. 
     BACKGROUND 
     As electronic devices are made increasingly smaller, internal components with the devices have increasingly less space in their respective device housings. Consequently, printed circuit board space is put at an increasingly high premium. In certain situations, there may not be space to install a solder pad having enough surface area to robustly couple with a grounding spring. Unfortunately, this can prevent device makers from including certain functionality or in some cases can be a constraint preventing smaller form factor device housings. 
     Therefore, what is desired is a reliable way to attach a ground spring to a printed circuit board having a constrained amount of space available. 
     SUMMARY 
     In one aspect, an electrically conductive connector is described. The electrically conductive connector may include a first second electrically conductive portion, second electrically conductive portion, and an overpass structure. The first electrically conductive portion and second electrically conductive portion may traverse along a PCB at or near a surface of corresponding portions of the PCB. The overpass structure may include an elevated portion formed of electrically conductive material that electrically connects the first and second portion and that overpasses another corresponding portion of the PCB. 
     In another aspect, a method of grounding a circuit board and protecting a plurality of components on a PCB is described. The method may include attaching an electrically conductive member to a first portion, a second portion, and a third portion. The method may further include attaching the first portion to a top surface of the PCB. The first portion may be electrically connected a first component of the PCB. The method may further include extending the second portion over a top surface of a second component of the PCB. The second component may extend above the top surface of the PCB, and the second portion may be free of connection to the PCB. The method may further include attaching the third portion to a lateral surface of the PCB. The third portion may be electrically connected a third component of the PCB. 
     In another aspect, a PCB is described. The PCB may include a first component electrically connected to the PCB, a second component electrically connected to the PCB, and a third component electrically connected to the PCB. The PCB may also include an electrically conducting member. The an electrically conducting member may include a first connector portion electrically connected to the first component, a second connector electrically connected to the second component, an overpass portion that extends over and above the third component. The overpass portion may be free of electrical connection to the third component. 
     Other systems, methods, features and advantages of the embodiments will be, or will become, apparent to one of ordinary skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description and this summary, be within the scope of the embodiments, and be protected by the following claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1A  shows a portion of a printed circuit board having a number of surface mounted components; 
         FIG. 1B  shows an overpass grounding spring coupled to the printed circuit board of  FIG. 1A ; 
         FIG. 2  shows a cross-sectional side view of the printed circuit board of  FIG. 1B ; 
         FIG. 3  shows the printed circuit board of  FIG. 1B  with shielding components configured to provide radio frequency shielding for a number of surface mounted components; and 
         FIG. 4  shows a block diagram illustrating a method for coupling an overpass grounding spring to a printed circuit board. 
     
    
    
     DETAILED DESCRIPTION 
     Representative applications of methods and apparatus according to the present application are described in this section. These examples are being provided solely to add context and aid in the understanding of the described embodiments. It will thus be apparent to one skilled in the art that the described embodiments may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the described embodiments. Other applications are possible, such that the following examples should not be taken as limiting. 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     A rounding spring may be utilized to provide an electrically conductive grounding path to components disposed within an electronic device housing, thereby dissipating a charge from a component that is electrically connected to the grounding spring. Grounding these components to chassis ground can help to electrically isolate the components and provide increased protection against electrical shock. In some embodiments, the grounding can also help to reduce electromagnetic interference between proximate components. A grounding spring can also be surface mounted to a printed circuit board (PCB) to provide a grounding path to components on the PCB. However, adhesion of the grounding spring to the printed circuit board can require a minimum amount of surface area to robustly couple the grounding spring to the PCB. When that minimal amount of surface area is unavailable, other attachment means can be required for robust adhesion. One solution to this problem is to use multiple attachment points to secure the grounding spring to the printed circuit board. Between the two attachment points the grounding spring can have the attachment area necessary to securely solder the grounding spring to the PCB. The grounding spring can be formed from various conductive metals including copper or stainless steel. In one embodiment, the grounding spring can be a plated steel strip that has undergone a cold rolling process. The strip can have a thickness of about 0.10-0.15 mm. Plating means may include nickel or tin. 
     In some embodiments, multi-point attachment of a grounding spring can have additional advantages including component protection. For example, a portion of the grounding spring disposed between the attachment points can pass over other surface mounted components on the PCB, thereby providing an amount of protection to the surface mounted components during a component assembly process. In another embodiment, the grounding spring can cooperate with shielding walls to provide an amount of RF shielding to the overpassed components. 
     These and other embodiments are discussed below with reference to  FIGS. 1-4 . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
       FIG. 1A  shows a perspective view of a printed circuit board (PCB)  102 . PCB  102  can be a main logic board (MLB) for a portable electronic device and can be attached to the portable electronic device by at least a fastener disposed through opening  104 . A solder pad  106  can be attached to a top surface of PCB  102 . Solder pad  106  can be in electrical communication with various electronic components disposed on PCB  102  and can be used, in conjunction with grounding spring  112  (shown in  FIG. 1B ), for grounding various electrical components disposed on PCB  102 . PCB  102  can also include a number of surface mounted components  108  proximate to solder pad  106 . A location of surface mounted components  108  can limit a size of solder pad  106  on PCB  102  as each of surface mounted components  108  along with associated electrical trace routing take up space on PCB  102  that in many cases cannot be overlapped by solder pad  106 . PCB  102  can also include edge plate  110  disposed on a lateral (or vertical) surface of PCB  102 . Edge plate  110  can be operable to route signals between a top and bottom surface of PCB  102 . Edge plate  110  can also be utilized in conjunction with grounding spring  112  to ground electronic components of PCB  102 . 
       FIG. 1B  shows how an overpass grounding spring can be mechanically and electrically coupled to PCB  102  at both solder pad  106  and edge plate  110 . In one embodiment, grounding spring  112  can be about 0.10-0.15 mm thick and be formed of cold rolled, plated steel, giving it high flexibility and strength. Grounding spring  112  further includes grounding contact  116  on a first portion  132  of grounding spring  112  that is flexibly connected to a ground chassis (not shown). As shown in  FIG. 1B , grounding contact  116  is generally round. However, in other embodiments, grounding contact  116  can have many different shapes or configurations that allow it to conform to a geometry of a housing or other component with which it is designed to be in contact. 
     An external downward force may be applied to an area generally near grounding contact  116 . Consequently, a resultant upward force can be generated to a top surface of solder pad  106  causing grounding spring  112  to detach from solder pad  106  at or near second portion  134  of grounding spring  112 . However, in this embodiment shown in  FIG. 1B , by extending grounding spring  112  above surface mounted components  108 , grounding spring  112  can also be coupled with edge plate  110  to provide additional strength against any forces acting on the grounding spring near grounding contact  116 . In addition, grounding spring  112  can provide an electrically conductive grounding path to two separate portions of PCB  102  without adversely affecting surface mounted components  108 . In other embodiments, at least some surface mounted components  108  can be electrically isolated from the electrically conductive grounding path formed by grounding spring  112 . In addition to providing two grounding points for PCB  102 , grounding spring  112  also includes overpass portion  114 , corresponding to third portion  136  of grounding spring  112 , which substantially covers surface mounted components  108 . Overpass portion  114  can prevent surface mounted components  108  from being disturbed during assembly of other components. It should be noted that in some configurations grounding spring  112  can be configured to contact three or more positions on PCB  102 , or in other configurations can extend between two separate PCBs. Also, as can be seen in  FIG. 1B , first portion  132  is at a level different from second portion  134 , and vice versa. Also, as can been seen in  FIG. 1B , third portion  136  is a level different from first portion  132  and different from second portion  134 . Accordingly, first portion  132  is not planar with respect to second portion  134 , and vice versa, and third portion  136  is not planar with respect to first portion  132  and with respect to second portion  134 . 
     The flexibility of grounding spring  112  allows grounding spring  112  to include a first joint  118  disposed between a portion of grounding spring  112  attached to solder pad  106  and overpass portion  114 . The external downward force exerted on grounding spring  112 , causing an upward force near first joint  118 , may be passed through first joint  118  and overpass portion  114 . Also, grounding spring  112  further includes a second joint  119  disposed between overpass portion  114  and a portion of grounding spring  112  attached to edge plate  110 . Additional forces that may otherwise cause grounding spring  112  to release from PCB  102  may further pass through second joint  119  and onto additional material of grounding spring  112 . 
     As shown in  FIG. 1B , grounding spring  112  generally has a width  121  configured to provide a mechanical shield for components located below overpass portion  114 . In some embodiments, grounding spring  112  may be wider to mechanically shield additional components. In other embodiments, grounding spring  112  may be narrower to mechanically shield fewer components. Still, in other embodiment, the width of grounding spring  112  may be configured to offset downward forces on grounding contact  116  to ensure grounding spring  112  does not detach from PCB  102  at any location. 
     Grounding spring  112  generally extends a length  122  from grounding contact  116  and from one end of PCB  102  to another end of PCB  102 . In some embodiments, length  122  may be longer to accommodate a longer (or wider) PCB  102  and/or to extend grounding contact  116  further from PCB  102 . In other embodiments, length  122  may be shorter in order to engage a smaller PCB  102 . 
       FIG. 2A  shows a cross-sectional view of PCB  102  and grounding spring  112 . Here, it can be seen that grounding spring  112  passes substantially above surface mounted components  108 . In some embodiments, surface mounted components  108  can be electrically grounded through either solder pad  106  or edge plate  110 . In other embodiments, surface mounted components  108  can be grounded through other pathways not depicted. For example, grounding spring  112  can be in direct contact with at least one of surface mounted components  108 . In such a configuration, the contacted surface mounted component can be coupled to overpass portion  114  by a grounding point configured to direct current along grounding spring  112 . 
       FIG. 3  shows another cross-sectional view of PCB  102 . In this depiction additional side shield  128  has been added to enclose surface mounted components  108  (not shown). Side shield  128  can be metal shielding capable of obscuring or completely blocking radio frequency emissions from affecting other proximate electronics. An additional side shield  118  can be disposed on an opposite side of overpass portion  114  so that surface mounted components  108  are completely surrounded by shielding elements. Because grounding spring  112  is also radio opaque, interference can also be prevented from escaping through grounding spring  112 . Side shield  128  further offers protection to surface mounted components  108  during a component assembly process. 
       FIG. 4  shows a block diagram illustrating a method  400  for attaching an overpass grounding spring to a PCB. In step  402  a first portion of the grounding spring is soldered to a solder pad disposed on the PCB. In step  404  a second portion of the grounding spring is soldered to an edge plated portion of the PCB, such that a third portion of the overpass disposed between the first and second portions passes over a number of components surface mounted to the PCB. In this way, several benefits can be realized. For example, components disposed between the soldered portions of the grounding spring can be electrically isolated from other components. Also, the second soldered portion increases a coupling strength between the grounding spring and the PCB. Further, grounding spring can be operable to provide mechanical protection for the surface mounted components. It should be noted that the above steps can be accomplished in series or in parallel. For example, the first and second portions of the grounding spring can be soldered to the PCB in a single soldering operation. 
     The various aspects, embodiments, implementations or features of the described embodiments can be used separately or in any combination. Various aspects of the described embodiments can be implemented by software, hardware or a combination of hardware and software. The described embodiments can also be embodied as computer readable code on a computer readable medium for controlling manufacturing operations or as computer readable code on a computer readable medium for controlling a manufacturing line. The computer readable medium is any data storage device that can store data which can thereafter be read by a computer system. Examples of the computer readable medium include read-only memory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, and optical data storage devices. The computer readable medium can also be distributed over network-coupled computer systems so that the computer readable code is stored and executed in a distributed fashion. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20140331
Publication Date: 20160913
Grant Date: 20160913
Priority Date: 20130904
Inventors: STEPHENS GREGORY N.
HILL MATTHEW D.
MYERS SCOTT A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01R2201/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0215", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/10265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R2201/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/4913", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R12/57", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0215", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T29/4913", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R4/64", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R12/57", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R4/64", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R12/57", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01R4/64", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01R2201/06", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/4913", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10265", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0215", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 52583844