PATENT DOCUMENT

Publication Number: US-8791864-B2
Application Number: US-201113018142-A
Country: US
Kind Code: B2

Title: Antenna structures with electrical connections to device housing members

Abstract:
Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include antenna structures that are formed from an internal ground plane and a peripheral conductive housing member. A conductive path may be formed that connects the peripheral conductive housing member and the internal ground plane. The conductive path may include a flex circuit. A metal structure may be welded to the peripheral conductive housing member. A solder pad and other traces in the flex circuit may be soldered to the metal structure at one end of the conductive path. At the other end of the conductive path, the flex circuit may be attached to the ground plane using a bracket, screw, and screw boss.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having conductive structures that form an antenna ground for an antenna and having a peripheral conductive member that runs around at least some edges of the housing and forms at least part of the antenna, wherein the antenna ground and the peripheral conductive member are separated by a gap; and 
 a conductive path that bridges the gap, wherein the conductive path includes a flex circuit that is attached to the peripheral conductive member, wherein the flex circuit comprises a flexible polymer substrate that bridges the gap, that contains at least one conductive trace, and that includes a solder pad electrically connected to the at least one conductive trace. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the gap comprises a dielectric-filled opening that includes at least some plastic. 
     
     
       3. The electronic device defined in  claim 1  further comprising a metal structure that forms part of the conductive path. 
     
     
       4. The electronic device defined in  claim 3  wherein the metal structure comprises a first metal coated with a second metal. 
     
     
       5. The electronic device defined in  claim 3  wherein the metal structure comprises a metal plate. 
     
     
       6. The electronic device defined in  claim 5  further comprising welds with which the metal plate is welded to the peripheral conductive member. 
     
     
       7. The electronic device defined in  claim 6  further comprising solder with which the metal plate is connected to a trace in the flex circuit, wherein the trace forms part of the conductive path. 
     
     
       8. The electronic device defined in  claim 7  wherein the peripheral conductive member comprises stainless steel and wherein the metal plate comprises a first metal that is at least partly coated with a plating layer of a second metal. 
     
     
       9. The electronic device defined in  claim 7  wherein the metal plate has opposing first and second surfaces, wherein the first surface is attached to the peripheral conductive member and wherein the second surface has a solder-compatible coating to which the solder is connected. 
     
     
       10. The electronic device defined in  claim 9  further comprising a screw and a bracket configured to attach the trace in the flex circuit to the antenna ground. 
     
     
       11. An electronic device, comprising:
 a housing having a peripheral conductive member; 
 ground plane structures; 
 a metal member welded to the peripheral conductive member with welds; and 
 a flexible polymer substrate that contains at least one conductive trace that is connected to the metal member, wherein the at least one conductive trace comprises a solder pad and wherein the flexible polymer substrate extends between the ground plane structures and the metal member. 
 
     
     
       12. The electronic device defined in  claim 11  wherein the solder pad is soldered to the metal member with solder. 
     
     
       13. The electronic device defined in  claim 12  further comprising dielectric layer portions that overlap at least part of the solder pad and help prevent the solder from contacting the metal member in the vicinity of the welds. 
     
     
       14. The electronic device defined in  claim 11  wherein the peripheral conductive member comprises a peripheral metal housing member having a rectangular ring shape. 
     
     
       15. The electronic device defined in  claim 14  wherein the ground plane structures and at least part of the peripheral metal housing member form at least one antenna in the electronic device and wherein the electronic device further comprises:
 a metal bracket interposed in an electrical path between the conductive trace and the ground plane structures. 
 
     
     
       16. The electronic device defined in  11  wherein the flexible polymer substrate comprises a flex circuit that contains the at least one conductive trace, wherein the metal member is interposed between the flex circuit and the peripheral conductive member, and wherein the metal member connects the conductive trace to the peripheral conductive member. 
     
     
       17. The electronic device defined in  11  wherein the conductive trace is soldered to the metal member. 
     
     
       18. The electronic device defined in  11  wherein the metal member comprises stainless steel coated with a plating layer. 
     
     
       19. The electronic device defined in  claim 18  wherein the plating layer comprises a material selected from the group consisting of: nickel, tin, and gold.

Description:
This application claims the benefit of provisional patent application No. 61/431,520, filed Jan. 11, 2011, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to conductive electronic device structures such as structures associated with antennas for supporting wireless communications. 
     Electronic devices such as cellular telephones and other devices often contain wireless communications circuitry. The wireless communications circuitry may include, for example, cellular telephone transceiver circuits for communicating with cellular telephone networks. Wireless communications circuitry in an electronic device may also include wireless local area network circuits and other wireless circuits. Antenna structures are used in transmitting and receiving wireless signals. 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to implement wireless communications circuitry such as antennas using compact arrangements. At the same time, it may be desirable to include conductive structures such as metal device housing components in an electronic device. Because conductive components can affect radio-frequency performance, care must be taken when incorporating antennas into an electronic device that includes conductive structures. In some arrangements, it may be desirable to use conductive housing structures in forming antenna structures for a device. Doing so may entail formation of electrical connections between different portions of the device. For example, it may be desirable to form an electrical connection between internal device components and a conductive peripheral housing member. Electrical connection arrangements based on springs have been used to form such connections. Spring-based connections may be satisfactory in some situations, but pose challenges because they are generally not insulated from their surroundings and can be challenging to adjust during manufacturing. Springs also present the possibility of becoming loose during daily use, which could pose reliability challenges. 
     It would therefore be desirable to be able to provide improved arrangements for forming electrical connections with conductive structures such as conductive electronic device housing members. 
     SUMMARY 
     Electronic devices may be provided that contain wireless communications circuitry. The wireless communications circuitry may include antenna structures that are formed from conductive housing structures. For example, an electronic device may be provided that has an antenna formed from an internal ground plane and a peripheral conductive housing member. 
     The ground plane and the peripheral conductive housing member may be separated by a gap. The antenna may include a conductive path that connects the peripheral conductive housing member and the internal ground plane across the gap. 
     The conductive path may include a flex circuit. A metal structure may be welded to the peripheral conductive housing member. A solder pad and other traces in the flex circuit may be soldered to the metal structure at one end of the conductive path. At the other end of the conductive path the flex circuit may be attached to the ground plane using a bracket, screw, and screw boss. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device of the type that may be provided with antenna structures in which an electrical connection is made to a conductive housing structure such as a conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 2  is a top interior view of an electronic device of the type shown in  FIG. 1  in which electrical connections are made to a conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 3  is a diagram showing illustrative structures that may be used in forming an electrical connection between an internal housing structure such as a ground plate member and a conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an interior portion of an electronic device of the type shown in  FIGS. 1 and 2  showing how a flex circuit and associated structures may be used in forming an electrical connection to a conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 5  is an exploded perspective view of an electronic device having a flex circuit connection arrangement of the type shown in  FIG. 4  in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of the flex circuit connection structures of  FIG. 5  in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of a flex circuit attached to a conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 8  is a side view of flex circuit structures and a portion of a conductive peripheral housing member during assembly using a hot bar tool in accordance with an embodiment of the present invention. 
         FIG. 9  is a side view of flex circuit structures and a portion of a conductive peripheral housing member during assembly using a hot bar tool and a support structure in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with wireless communications circuitry. The wireless communications circuitry may be used to support wireless communications in one or more wireless communications bands. Antenna structures in an electronic device may be used in transmitting and receiving radio-frequency signals. 
     An illustrative electronic device that contains wireless communications circuitry is shown in  FIG. 1 . Device  10  of  FIG. 1  may be a notebook computer, a tablet computer, a computer monitor with an integrated computer, a desktop computer, or other electronic equipment. If desired, electronic device  10  may be a portable device such as a cellular telephone, a media player, other handheld devices, a wrist-watch device, a pendant device, an earpiece device, or other compact portable device. 
     As shown in  FIG. 1 , device  10  may have a housing such as housing  11 . Housing  11  may be formed from materials such as plastic, metal, carbon fiber and other fiber composites, ceramic, glass, wood, other materials, or combinations of these materials. Device  10  may be formed using a unibody construction in which some or all of housing  11  is formed from a single piece of material (e.g., a single cast or machined piece of metal, a single piece of molded plastic, etc.) or may be formed from frame structures, housing sidewall structures, and other structures that are assembled together using fasteners, adhesive, and other attachment mechanisms. In the illustrative arrangement shown in  FIG. 1 , housing  11  includes conductive peripheral housing member  12 . Conductive peripheral housing member  12  may have a ring shape that runs around the rectangular periphery of device  10 . One or more gaps such as gaps  30  may be formed in conductive peripheral housing member  12 . Gaps such as gaps  30  may be filled with dielectric such as plastic and may interrupt the otherwise continuous shape of conductive peripheral housing member. Conductive peripheral housing member may have any suitable number of gaps  30  (e.g., more than one, more than two, three or more, less than three, etc.). 
     Conductive peripheral housing member  12  may be formed from a durable material such as metal. Stainless steel may be used for forming housing member  12  because stainless steel is aesthetically appealing, strong, and can be machined during manufacturing. Other metals may be used if desired. The rear face of housing  11  may be formed from plastic, glass, metal, ceramic composites, or other suitable materials. For example, the rear face of housing  11  may be formed form a plate of glass having regions that are backed by a layer of internal metal for added strength. Conductive peripheral housing member  12  may be relatively short in vertical dimension Z (e.g., to serve as a bezel for display  14 ) or may be taller (e.g., to serve as the sidewalls of housing  11  as shown in the illustrative arrangement of  FIG. 1 ). 
     Device  10  may include components such as buttons, input-output port connectors, ports for removable media, sensors, microphones, speakers, status indicators, and other device components. As shown in  FIG. 1 , for example, device  10  may include buttons such as menu button  16 . Device  10  may also include a speaker port such as speaker port  18  (e.g., to serve as an ear speaker for device  10 ). 
     One or more antennas may be formed in device  10 . The antennas may, for example, be formed in locations such as locations  24  and  26  to provide separation from the conductive elements of display  14 . Antennas may be formed using single band and multiband antenna structures. Examples of communications bands that may be covered by the antennas include cellular telephone bands (e.g., the bands at 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz), satellite navigation bands (e.g., the Global Positioning System band at 1575 MHz), wireless local area network bands such as the IEEE 802.11 (WiFi®) bands at 2.4 GHz and 5 GHz, the Bluetooth band at 2.4 GHz, etc. Examples of antenna configurations that may be used for the antennas in device  10  include monopole antennas, dipole antennas, strip antennas, patch antennas, inverted-F antennas, coil antennas, planar inverted-F antennas, open slot antennas, closed slot antennas, loop antennas, hybrid antennas that include antenna structures of multiple types, or other suitable antenna structures. 
     Device  10  may include one or more displays such as display  14 . Display  14  may be a liquid crystal display (LCD), an organic light-emitting diode (OLED) display, a plasma display, an electronic ink display, etc. A touch sensor may be incorporated into display  14  (i.e., display  14  may be a touch screen). The touch sensor may be an acoustic touch sensor, a resistive touch sensor, a piezoelectric touch sensor, a capacitive touch sensor (e.g., a touch sensor based on an array of indium tin oxide capacitor electrodes), or a touch sensor based on other touch technologies. 
     Display  14  may be covered by a transparent planar conductive member such as a layer of glass or plastic. The cover layer for display  14 , which is sometimes referred to as a cover glass layer or cover glass, may extend over substantially all of the front face of device  10 , as shown in  FIG. 1 . The rectangular center portion of the cover glass (surrounded by dashed line  20  in  FIG. 1 ) contains an array of image pixels and is sometimes referred to as the active portion of the display. The peripheral outer portion of the cover glass (i.e., rectangular peripheral ring  22  of  FIG. 1 ) does not contain any active image pixels and is sometimes referred to as the inactive portion of display  14 . A patterned opaque masking layer such as a peripheral ring of black ink may be formed under inactive portion  22  to hide interior device components from view by a user. 
       FIG. 2  is a top view of the interior of device  10  showing how antennas  40 L and  40 U may be implemented within housing  12 . As shown in  FIG. 2 , ground plane G may be formed within housing  12 . Ground plane G may form antenna ground for antennas  40 L and  40 U. Because ground plane G may serve as antenna ground, ground plane G may sometimes be referred to as antenna ground, ground, or a ground plane element (as examples). One or more printed circuit boards or other mounting structures may be used to mount components  31  in device  10 . Components  31  may include radio-frequency transceiver circuits that are coupled to antennas  40 U and  40 L using transmission lines  52 L and  52 U, processors, application-specific integrated circuits, cameras, sensors, switches, connectors, buttons, and other electronic device components. 
     In central portion C of device  10 , ground plane G may be formed by conductive structures such as a conductive housing midplate member (sometimes referred to as an internal housing plate or planer internal housing structures). The structures of ground plane G may be connected between the left and right edges of member  12 . Printed circuit boards with conductive ground traces (e.g., one or more printed circuit boards used to mount components  31 ) may form part of ground plane G. 
     The midplate member may have one or more individual sections (e.g., patterned sheet metal sections) that are welded together. Portions of the midplate structures may be covered with insert-molded plastic (e.g., to provide structural support in portions of the interior of device where no conductive ground is desired, such dielectric-filled portions of antennas  40 U and  40 L in regions  24  and  26 ). 
     At ends  24  and  26  of device  10 , the shape of ground plane G may be determined by the shapes and locations of conductive structures that are tied to ground. Ground plane G in the simplified layout of  FIG. 2  has a straight upper edge UE and a straight lower edge LE. In actual devices, the upper and lower edges of ground plane G and the interior surface of conductive peripheral housing member  12  generally have more complex shapes determined by the shapes of individual conductive structures that are present in device  10 . Examples of conductive structures that may overlap to form ground plane G and that may influence the shape of the inner surface of member  12  include housing structures (e.g., a conductive housing midplate structure, which may have protruding portions), conductive components (e.g., switches, cameras, data connectors, printed circuits such as flex circuits and rigid printed circuit boards, radio-frequency shielding cans, buttons and conductive button mounting structures), and other conductive structures in device  10 . In the illustrative layout of  FIG. 2 , the portions of device  10  that are conductive and tied to ground to form part of ground plane G are shaded and are contiguous with central portion C. 
     Openings such as openings  138  and  140  (sometimes referred to as gaps) may be formed between ground plane G and respective portions of peripheral conductive housing member  12 . Openings  138  and  140  may be filled with air, plastic, and other dielectrics and are therefore sometimes referred to as dielectric-filled gaps or openings. Openings  138  and  140  may be associated with antenna structures  40 U and  40 L. 
     Lower antenna  40 L may be formed by a loop antenna structure having a shape that is determined at least partly by the shape of the lower portions of ground plane G and conductive housing member  12 . In the example of  FIG. 2 , opening  138  is depicted as being rectangular, but this is merely illustrative. In practice, the shape of opening  138  may be dictated by the placement of conductive structures in region  26  such as a microphone, flex circuit traces, a data port connector, buttons, a speaker, etc. 
     Lower antenna  40 L may be fed using an antenna feed made up of positive antenna feed terminal  58 L and ground antenna feed terminal  54 L. Transmission line  52 L may be coupled to the antenna feed for lower antenna  40 L. Gap  30 ′ may form a capacitance that helps configure the frequency response of antenna  40 L. If desired, device  10  may have conductive housing portions, matching circuit elements, and other structures and components that help match the impedance of transmission line  52 L to antenna  40 L. 
     Antenna  40 U may be a two-branch inverted-F antenna. Transmission line  52 U may be used to feed antenna  40 U at antenna feed terminals  58 U and  54 U. Conductive structures  150  may form a shorting path that bridges dielectric opening  140  and electrically shorts ground plane G to peripheral housing member  12 . Conductive structure  148  (which may be formed using structures of the type used in forming structures  150  or other suitable structures) and matching circuit M may be used to connect antenna feed terminal  58 U to peripheral conductive member  12  at point  152 . Conductive structures such as structures  148  and  150  (which are sometimes referred to as conductive paths) may be formed by flex circuit traces, conductive housing structures, springs, screws, welded connections, solder joints, brackets, metal plates, or other conductive structures. 
     Gaps such as gaps  30 ′,  30 ″, and  30 ′″ (e.g., gaps  30  of  FIG. 1 ) may be present in peripheral conductive member  12 . A phantom gap may be provided in the lower right-hand portion of device  10  for aesthetic symmetry if desired. The presence of gaps  30 ′,  30 ″, and  30 ′″ may divide peripheral conductive housing member  12  into segments. As shown in  FIG. 2 , peripheral conductive member  12  may include first segment  12 - 1 , second segment  12 - 2 , and third segment  12 - 3 . 
     Segment  12 - 1  may form antenna resonating element arms for antenna  40 U. In particular, a first portion (segment) of segment  12 - 1  may extend from point  152  (where segment  12 - 1  is fed) to the end of segment  12 - 1  that is defined by gap  30 ″ and a second portion (segment) of segment  12 - 1  may extend from point  152  to the opposing end of segment  12 - 1  that is defined by gap  30 ′″. The first and second portions of segment  12 - 1  may form respective branches of an inverted F antenna and may be associated with respective low band (LB) and high band (HB) antenna resonances for antenna  40 U. The relative positions of structures  148  and  150  along the length of member  12 - 1  may affect the response of antenna  40 U and may be selected to tune antenna  40 U. Antenna tuning adjustments may also be made by adjusting matching circuit M, by adjusting the configuration of components used in forming paths  148  and  150 , by adjusting the shapes of opening  140 , etc. Antenna  40 L may likewise be adjusted. 
     With one illustrative arrangement, antenna  40 L may cover the transmit and receive sub-bands in five communications bands (e.g., 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz). Antenna  40 U may, as an example, be configured to cover a subset of these five illustrative communications bands. For example, antenna  40 U may be configured to cover a two receive bands of interest and, with tuning, four receive bands of interest. 
     Illustrative structures that may be used to form shorting path  150  of  FIG. 2  (e.g., the electrical path in antenna  40 U that spans peripherally enclosed dielectric opening  140  and to short conductive peripheral housing member  12  to ground plane G) are shown schematically in  FIG. 3 . As shown in  FIG. 3 , path  150  may include one or more components such as flex circuit  160  that can be adjusted as part of the manufacturing process used to form device  10 . Flex circuits, which are also sometimes referred to as flexible printed circuits, contain layers of flexible dielectric (typically polyimide or other flexible polymer sheets) and conductive traces (e.g. metal traces such as copper traces or copper traces coated with gold). The layout of the trace pattern on a flex circuit can be adjusted separately from the layout of the remaining structures in device  10  (e.g., the size and shape of structural members such as midplate structures G and conductive peripheral housing member  12 ). Tuning components such as resistors, capacitors, and inductors can also be added to a flex circuit. Adjustments to antenna  40 U may generally be made more readily by changing the tuning components and trace layout for a structure such as flex circuit  160  than by changing the machining of member  12  or other housing structures. 
     As shown in  FIG. 3 , flex circuit  160  includes one or more traces such as trace  162 . Changes that may be made to path  150  to adjust antenna  40 U include changes to the length of trace  162 , changes to the width of trace  162 , changes to the shape of trace  162 , the addition or removal of matching circuit components on flex circuit  162  such as the addition or removal of capacitors, resistors, inductors, and other changes to the properties of flex circuit  160  and other structures shown in  FIG. 3 . 
     In the illustrative arrangement of  FIG. 3 , flex circuit  160  has been connected to conductive peripheral housing member  12  (e.g., housing member segment  12 - 1 ) using a combination of solder and welds. Welds  164  have been used to connect metal member  166  to conductive peripheral housing member  12 . Metal member  166  may be a metal plate having one or more openings (not shown in  FIG. 3 ) that permit solder  172  to penetrate and help hold member  166  in place. Solder  172  may form a connection between metal member  166  and traces on flex circuit  160  such as solder pad  168 . 
     Flex circuit dielectric layer portions such as dielectric structures  170  may help prevent solder  172  from flowing under metal member  166  in the vicinity of welds  164 . The process of forming welds  164  tends to disrupt the surface of member  166  in the vicinity of welds  164  (e.g., by disrupting or even removing some of the surface coating layer of member  166  in configurations where a solder-compatible coating is formed on member  166 ). This disrupted surface on member  166  is not as suitable as other portions of member  166  (e.g., the portions of member  166  in region  184 ) for forming consistent solder joints with solder  172 . It may therefore be desirable to interpose dielectric structures such as structures  170  between flex circuit  160  and member  166  in the regions of member  166  that have been exposed to welding (i.e., the portions of member  166  in the vicinity of welds  164  in the  FIG. 3  example). Because structures  170  cover the edges of solder pad  168  (in the illustrative arrangement of  FIG. 3 ), these portions of solder pad  168  will repel solder  172 . Solder  172  will therefore be confined to the portions of member  166  away from welds  164 . 
     To ensure satisfactory formation of welds  164  between member  166  and housing member  12  while simultaneously forming a satisfactory solder joint between member  166  and solder pad  168  on flex circuit  160 , it may be desirable to form member  166  from a material such as nickel (or other materials such a tin, gold, etc.). As an example, member  166  may be formed from a stainless steel plate that has been plated with nickel or other solder-compatible coating. The nickel coating or other solder-compatible coating on member  166  may help solder  172  adhere to member  166  while forming a good electrical connection between solder  172  and member  166 . Solder pad  168  may be formed from gold plated copper or other conductor that forms a satisfactory bond with solder  172 . 
     Traces  162  in flex circuit  160  may be soldered to bracket  174  using solder  176 . If desired, bracket  174  may be soldered to flex circuit  160  before flex circuit  160  is installed in device  10  to form path  150 . Metal screw  178  may be used to form an electrical and mechanical connection to metal screw boss  180 . Screw boss  180  may be welded to ground plane G (e.g., a metal midplate member or other internal housing structures) using welds  182 . The metal midplate member or other structures of ground plane G may be formed from stainless steel (e.g., sheet metal) structures that have been machined to form mounting features for receiving internal device components. 
       FIG. 4  is an exploded perspective view of illustrative structures that may be used in forming conductive path  150 . As shown in  FIG. 4 , conductive peripheral housing member may have a feature such as lip  186  or other protruding structure to which member  166  may be attached (e.g., using welds  164  of  FIG. 3  to attach member  166  to the underside of lip  186 ). Solder may flow into hole  194  to help hold the structures of path  150  together following soldering. 
     Bracket  174  may have prongs  190  surrounding opening  192 . Opening  192  may receive screw  178  when screw  178  is screwed into screw boss  180  ( FIG. 3 ). When assembled, current can flow from the internal traces of flex circuit  160  into bracket  174 , screw  178 , screw boss  180 , and into ground G (to which boss  180  is connected). 
       FIG. 5  is an exploded perspective view of device  10  in the vicinity of path  150 . Ground plane G (e.g., the midplate housing structure for device  10 ) may include regions such as plastic-coated sheet metal region  198 . Plastic extension plate  196  extends into region  140  along the upper edge of ground G. Because extension plate  196  is formed from dielectric, plate  196  forms part of dielectric opening  140 . 
     Shielding layer portions  170  (e.g., a layer of patterned polyimide associated with flex circuit  160 ) may cover only part of each end of solder pad  168  (i.e., the portion under welds  164  between member  166  and lip  186  of peripheral conductive housing member  12 ), so that the exposed portion of solder pad  168  that is visible in  FIG. 5  forms a “T” shape. Other patterns of polyimide or other materials may be used to prevent solder on pad  168  from contacting the underside of member  166  in the vicinity of welds  164  if desired. 
       FIG. 6  is perspective view of the interior portions of device  10  of  FIG. 5 . As shown in  FIG. 6 , when member  166  is attached to the lower portion of lip  168  of peripheral conductive housing member  12 , a portion of member  166  may protrude sufficiently to expose a portion of opening  194 . Pad  168  may also protrude somewhat from under member  166 . 
     A cross-sectional side view of member  166  on peripheral conductive housing member  12  taken along line  200  of  FIG. 6  and viewed in direction  202  is shown in  FIG. 7 . As shown in  FIG. 7 , the protrusion of solder pad  168  from under the edge of member  166  allows solder portion  172 - 1  to extend up front face  204  of member  166 . Hole  194  allows solder  172 - 2  to extend up front face  206  of lip portion  186  of peripheral conductive housing member. Distributing solder  172  in this way may help hold the structures of  FIG. 7  in place. 
     Soldering operations may be performed using a hot-bar technique of the type illustrated in  FIG. 8 . As shown in  FIG. 8 , the underside of member  166  may be coated with solder flux  212  following welding of member  166  to peripheral conductive housing member  12  with welds  164 . Hot-bar soldering head  208  may be moved upwards in direction  210 . This compresses flex circuit  160  against member  166  and peripheral conductive housing member  12 . Solder  172  is melted by the heat from hot bar  208 , thereby forming a solder joint between the traces of flex circuit  160  and member  166 . Member  166  is preferably formed from a material that accepts solder joints (e.g., nickel-plated stainless steel). If desired, a portion of peripheral conductive member  12  may be machined to form structure  166  and plated with nickel or other suitable substances for facilitating solder joint formation. The use of a separate member such as member  166  that is welded to peripheral conductive housing member  12  is merely illustrative. 
     Another illustrative hot-bar soldering arrangement that may be used in attaching flex circuit  160  to peripheral conductive housing member  12  is shown in  FIG. 9 . With an arrangement of the type shown in  FIG. 9 , hot-bar soldering head  208  may bear against peripheral conductive housing member  12  in direction  214 , rather than direction  210 . To ensure that the structures of  FIG. 9  are compressed together during soldering, support  216  may be press against flex circuit  160  in opposing direction  210 . 
     The use of hot bar soldering to form the connection between flex circuit  160  and member  166  and thereby peripheral conductive housing member  12  is merely illustrative. Other types of connections may be formed if desired. 
     For example, laser soldering techniques may be used to supply the heat necessary to melt solder  172  instead of using hot bar  208 . 
     As another example, a piece of self-igniting material (e.g., Nanofoil®) may be placed in the solder joint in place of solder flux  212 . An exposed tail portion of the self-igniting material may be exposed to laser light to initiate ignition. The self-igniting material may then consume itself and generate sufficient heat to form the solder joint. 
     If desired, member  166  may be soldered to flex circuit  160  before attachment to peripheral conductive housing member  12 . Following attachment of member  166  and flex  160 , the assembly formed by member  166  and flex  160  may be welded to peripheral conductive housing member  12 . 
     Materials such as conductive epoxy or other conductive adhesives may also be used in attaching flex circuit  160 . With this type of arrangement, solder  172  may be replaced with conductive adhesive. 
     The use of conductive adhesive or solder can be reduced or eliminated by treating the surfaces of the components that are being connected. For example, a diamond-impregnated gold plating layer may be formed on pad  168 . Flex circuit  160  may then be compressed against peripheral conductive housing member  12  using a bracket with a rubber shim. When compressed in this way, the sharp diamond particles or other particles in the surface of flex circuit  160  may penetrate into peripheral conductive housing member  12  to form a satisfactory electrical contact. 
     If desired, member  166  may be plated differently on each of its sides. For example, one side of member  166  may be plated with nickel (e.g., to receive solder  172 ) and the other side of member  166  may be plated with a substance that is optimized for forming welds  164  or may be left unplated. As another example, a tin-based plating may be formed adjacent to solder  172  and flex circuit  160  and a nickel plating layer may be formed on the side of member  166  adjacent to welds  164 . Gold plating may be formed on the solder side and the other side left unplated, etc. Using a plating configuration in which one side is optimized for forming solder joints (e.g., using tin plating or nickel plating) while the other side is optimized for forming welds (e.g., by being left unplated rather than including a coating such as tin that might impede welds) may help member  166  form a connection both to structures such as member  12  that benefit from the use of welds and structures such as pad  168  and flex circuit  160  that benefit from the use of solder. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20110131
Publication Date: 20140729
Grant Date: 20140729
Priority Date: 20110111
Inventors: MERZ NICHOLAS G. L.
MYERS SCOTT A.
DARNELL DEAN F.
SCHLUB ROBERT W.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/50", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/10", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 46454860