PATENT DOCUMENT

Publication Number: US-10908654-B2
Application Number: US-201816134738-A
Country: US
Kind Code: B2

Title: Display grounding structures

Abstract:
An electronic device may be provided with a display and conductive sidewalls. The display may include conductive display structures and a cover layer. The cover layer may be mounted to the sidewalls. The sidewalls may define antenna apertures for antennas in the device. Grounding structures may be coupled between the conductive display structures and the sidewalls at locations that at least partially overlap the antenna apertures. The grounding structures may include conductive tape having an adhesive surface. The conductive tape may have a first end at which the adhesive surface is coupled to the conductive display structures. The conductive tape may have a second end that is folded around a layer of heat-activated film and that is coupled to both the display cover layer and the conductive sidewalls. Conductive tape overlapping each antenna aperture may be concurrently assembled into the electronic device as the display is mounted to the sidewalls.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a device housing having a conductive sidewall; 
 a display having conductive display structures and a display cover layer overlapping the conductive display structures, wherein the display cover layer has opposing upper and lower surfaces, the lower surface is mounted to the conductive sidewall, and the lower surface is coupled to the conductive display structures; and 
 grounding structures coupled between the conductive display structures and the conductive sidewall, wherein the grounding structures are interposed between the lower surface and the conductive sidewall and the grounding structures are configured to electrically couple the conductive display structures to the conductive sidewall and to adhere a portion of the display cover layer to the conductive sidewall. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the grounding structures comprise conductive tape. 
     
     
       3. The electronic device defined in  claim 2 , wherein the conductive tape has a first end coupled to the conductive display structures and a second end coupled to the conductive sidewall, the second end being folded about an axis. 
     
     
       4. The electronic device defined in  claim 3 , wherein the conductive tape has an adhesive surface that is coupled to the conductive display structures, the display cover layer, and the conductive sidewall. 
     
     
       5. The electronic device defined in  claim 4 , wherein the conductive tape has a non-adhesive surface that opposes the adhesive surface. 
     
     
       6. The electronic device defined in  claim 4 , wherein the conductive tape has a first portion adhered to the display cover layer and a second portion adhered to the conductive sidewall and extending parallel to the first portion. 
     
     
       7. The electronic device defined in  claim 6 , wherein the grounding structures further comprise heat-activated film interposed between the first and second portions of the conductive tape. 
     
     
       8. The electronic device defined in  claim 7 , wherein the heat-activated film is offset from the second end of the conductive tape. 
     
     
       9. The electronic device defined in  claim 2 , wherein the conductive tape has a first end coupled to the conductive display structures and a second end that is folded around a layer of heat-activated film, wherein the second end is coupled to a ledge on the conductive sidewall, and wherein the layer of heat-activated film and the second end of the conductive tape are interposed between the lower surface and the ledge. 
     
     
       10. The electronic device defined in  claim 9 , further comprising:
 a layer of pressure-sensitive adhesive on the ledge and configured to adhere the display cover layer to the conductive sidewall. 
 
     
     
       11. The electronic device defined in  claim 10 , wherein the layer of pressure-sensitive adhesive comprises a notch and wherein the second end of the conductive tape is adhered to the ledge within the notch. 
     
     
       12. The electronic device defined in  claim 2 , wherein the grounding structures further comprise a conductive spring finger. 
     
     
       13. The electronic device defined in  claim 1 , further comprising:
 an antenna having an antenna aperture configured to radiate radio-frequency signals through the display cover layer, wherein the conductive sidewall is configured to define at least part of the antenna aperture and wherein the grounding structures at least partially overlap the antenna aperture. 
 
     
     
       14. The electronic device defined in  claim 1 , wherein the grounding structures comprise an air loop gasket. 
     
     
       15. Grounding structures for a display in an electronic device, the grounding structures comprising:
 conductive tape having opposing first and second lateral surfaces, wherein the first lateral surface comprises an adhesive surface and the conductive tape comprises a first portion and a second portion that extends from an end of the first portion; and 
 a layer of heat-activated film coupled to the second lateral surface, wherein the layer of heat-activated film is interposed between the first and second portions of the conductive tape and couples the first portion of the conductive tape to the second portion of the conductive tape. 
 
     
     
       16. The grounding structures defined in  claim 15 , wherein the first portion of the conductive tape extends parallel to the second portion of the conductive tape. 
     
     
       17. The grounding structures defined in  claim 15 , wherein the second lateral surface of the conductive tape comprises a non-adhesive surface. 
     
     
       18. A method of assembling an electronic device having a display and conductive housing walls, the method comprising:
 attaching pressure-sensitive adhesive, a first conductive tape, and a second conductive tape to a dielectric liner; 
 with the dielectric liner, concurrently attaching the pressure-sensitive adhesive, the first conductive tape, and the second conductive tape to the display; and 
 with a heat press, pressing the display onto the conductive housing walls to affix the pressure-sensitive adhesive, the first conductive tape, and the second conductive tape to the conductive housing walls. 
 
     
     
       19. The method defined in  claim 18 , wherein the electronic device comprises first and second antenna apertures that are at least partially defined by the conductive housing walls, wherein the heat press comprises first and second heated press heads, and wherein the method further comprises:
 with the first heated press head, heating the first conductive tape while pressing on the display at a first location overlapping the first conductive tape; and 
 with the second heated press head, heating the second conductive tape while pressing on the display at a second location overlapping the second conductive tape, wherein the first conductive tape at least partially overlaps the first antenna aperture and the second conductive tape at least partially overlaps the second antenna aperture in the electronic device.

Description:
FIELD 
     This relates generally to electronic devices, and more particularly, to electronic devices with wireless circuitry. 
     BACKGROUND 
     Electronic devices often include wireless circuitry with antennas. For example, cellular telephones, computers, and other devices often contain antennas for supporting wireless communications. 
     It can be challenging to form electronic device antenna structures with desired attributes. In some wireless devices, the presence of conductive structures such as conductive housing structures and conductive components can influence antenna performance. Antenna performance may not be satisfactory if the conductive structures are not configured properly and interfere with antenna operation or if antennas are undesirably influenced due to conductive structures in nearby components. Device size can also affect performance. It can be difficult to achieve desired performance levels in a compact device, particularly when the compact device has conductive components and housing structures. 
     It would therefore be desirable to be able to provide improved wireless circuitry for electronic devices such as electronic devices that include conductive structures. 
     SUMMARY 
     An electronic device may be provided with a display and a device housing having conductive sidewalls. The display may include conductive display structures and a display cover layer overlapping the conductive display structures. The display cover layer may be mounted to the conductive sidewalls. The conductive sidewalls may at least partially define one or more antenna apertures for antennas in the electronic device. In order to optimize antenna efficiency and bandwidth through the display, grounding structures may be coupled between the conductive display structures and the conductive sidewalls at locations that at least partially overlap each antenna aperture. 
     The grounding structures may include conductive tape having an adhesive surface and an opposing non-adhesive surface. The conductive tape may have a first end at which the adhesive surface is coupled to the conductive display structures. The conductive tape may have a second end that is folded around a layer of heat-activated film and that is coupled to both the display cover layer and the conductive sidewalls. The conductive tape may electrically couple the conductive display structures to a ground potential through the conductive sidewalls. Heat-activated, pressure-sensitive adhesive may also be used to adhere the display cover layer to the conductive sidewalls. The heat activated, pressure-sensitive adhesive may include a notch that accommodates the conductive tape. 
     A heat press may be used to press the display onto the conductive housing walls during assembly of the electronic device. The heat press may heat the heat-activated film to allow the display cover layer to be pressed until an exterior surface of the display cover layer lies flush with a top surface of the conductive sidewalls. Conductive tape overlapping each antenna aperture in the device may be concurrently assembled into the electronic device. This may serve to minimize variations in the height of the exterior surface of the display cover layer relative to the top surface of the conductive sidewalls across the front face of the device, for example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of illustrative circuitry in an electronic device in accordance with an embodiment. 
         FIG. 3  is a top-down view of an illustrative electronic device having multiple antennas formed at different locations around a display in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view showing how grounding structures for a display may be formed from conductive tape that secures the display to an electronic device housing in accordance with an embodiment. 
         FIG. 5  is a top-down view showing how conductive tape may be placed within a notch in a pressure-sensitive adhesive layer in accordance with an embodiment. 
         FIGS. 6 and 7  are side views showing how conductive tape may be compressed when used to mount a display to an electronic device housing in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view showing how an air loop gasket may be used to form conductive grounding structures for a display in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view showing how a conductive spring may be used to form conductive grounding structures for a display in accordance with an embodiment. 
         FIG. 10  is flow chart of illustrative steps that may be performed in assembling an electronic device having conductive grounding structures formed from conductive tape in accordance with an embodiment. 
         FIGS. 11A and 11B  are diagrams of an illustrative assembly process for an electronic device having conductive grounding structures formed from conductive tape in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may be provided with conductive structures that are used to form one or more antennas. The conductive structures may include conductive housing structures. The electronic device may include a display having a display module overlapped by a display cover layer. The display module may include conductive display structures. The display cover layer may be secured to the conductive housing structures using adhesive. 
     The conductive display structures may occupy a significant portion of the lateral area of the display in order to provide as large an active area as possible for the display. This may limit the volume within the electronic device available to form the antennas. If care is not taken, confining antenna volume in this way can limit antenna bandwidth and efficiency. Similarly, the conductive display structures can block the antennas from radiating through the display cover layer with satisfactory bandwidth and efficiency. 
     In order to maximize bandwidth and efficiency for the antennas, the display may be coupled to a ground potential using conductive grounding structures. Each antenna may have a corresponding antenna aperture. The grounding structures may be coupled between the conductive display structures and the conductive housing structures at one or more locations that at least partially overlap the antenna aperture for each antenna. The grounding structures may also be used to help secure the display to the conductive housing structures. 
     As an example, the grounding structures may include conductive tape having an adhesive surface and a non-adhesive surface. The adhesive surface at a first end of the conductive tape may be coupled to the conductive display structures. The adhesive surface at a second end of the conductive tape may be coupled to a ledge or datum of the conductive housing structures. The second end of the conductive tape may be folded around a layer of heat-activated film. The heat-activated film may allow the second end of the conductive tape to be compressed during assembly of the electronic device. This may help to ensure that the display cover layer lies flush with a top surface of the conductive housing structures. 
     Other adhesives such as a layer of heat activated, pressure-sensitive adhesive may be used to help mount the display cover layer to the conductive housing structures. This pressure-sensitive adhesive may have a notch to accommodate the conductive tape. Grounding structures overlapping each antenna in the electronic device may be concurrently assembled into the electronic device to minimize manufacturing variations between the antennas. For example, the grounding structures overlapping each antenna may be assembled into the electronic device during the same assembly process used to mount the display to the conductive housing structures. 
     As an example, the pressure-sensitive adhesive and grounding structures for each antenna may be mounted to the same dielectric liner. The conductive display structures may be mounted to the display cover layer and placed within a fixture. The liner may be aligned with the fixture and may be pressed onto the display to mount the pressure-sensitive adhesive and the grounding structures to the display. The display may then be mounted to the conductive housing structures. A heat press may press the display onto the conductive housing structures to activate the pressure-sensitive adhesive. Heated press heads may be used to press on the display cover layer at locations overlapping the grounding structures to activate the heat activated film in each of the ground structures. Assembling the electronic device in this way may serve to minimize variations in height of the display cover layer over the conductive housing structures across the lateral face of the electronic device. 
     An electronic device that may include a display and conductive grounding structures for the display is shown in  FIG. 1 . Electronic devices such as electronic device  10  of  FIG. 1  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. 
     For example, the wireless communications circuitry of device  10  may include a Global Position System (GPS) receiver that handles GPS satellite navigation system signals at 1575 MHz or a GLONASS receiver that handles GLONASS signals at 1609 MHz. Device  10  may also contain wireless communications circuitry that operates in communications bands such as cellular telephone bands and wireless circuitry that operates in communications bands such as the 2.4 GHz Bluetooth® band and the 2.4 GHz and 5 GHz Wi-Fi® wireless local area network bands (sometimes referred to as IEEE 802.11 bands or wireless local area network communications bands). Device  10  may also contain wireless communications circuitry for implementing near-field communications at 13.56 MHz or other near-field communications frequencies. If desired, device  10  may include wireless communications circuitry for communicating at 60 GHz, circuitry for supporting light-based wireless communications, or other wireless communications. 
     The wireless communications circuitry may include one more antennas. The antennas of the wireless communications circuitry can include loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, dipole antennas, monopole antennas, helical antennas, waveguide antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. 
     Electronic device  10  may be a portable electronic device or other suitable electronic device. For example, electronic device  10  may be a laptop computer, a tablet computer, a somewhat smaller device such as a wrist-watch device, pendant device, headphone device, earpiece device, or other wearable or miniature device, a handheld device such as a cellular telephone, a media player, or other small portable device. Device  10  may also be a set-top box, a desktop computer, a display into which a computer or other processing circuitry has been integrated, a display without an integrated computer, a wireless access point, wireless base station, an electronic device incorporated into a kiosk, building, or vehicle, or other suitable electronic equipment. 
     Device  10  may include a housing such as housing  12 . Housing  12 , which may sometimes be referred to as a case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of these materials. In some situations, parts of housing  12  may be formed from dielectric or other low-conductivity material (e.g., glass, ceramic, plastic, sapphire, etc.). In other situations, housing  12  or at least some of the structures that make up housing  12  may be formed from metal elements. 
     Device  10  may, if desired, have a display such as display  14 . Display  14  may be mounted on the front face of device  10 . Display  14  may be a touch screen that incorporates capacitive touch electrodes or may be insensitive to touch. The rear face of housing  12  (i.e., the face of device  10  opposing the front face of device  10 ) may have a substantially planar housing wall such as rear housing wall  12 R (e.g., a planar housing wall). Rear housing wall  12 R may have slots that pass entirely through the rear housing wall and that therefore separate portions of housing  12  from each other. 
     Rear housing wall  12 R may include conductive portions and/or dielectric portions. If desired, rear housing wall  12 R may include a planar metal layer covered by a thin layer or coating of dielectric such as glass, plastic, sapphire, or ceramic. Housing  12  may also have shallow grooves that do not pass entirely through housing  12 . The slots and grooves may be filled with plastic or other dielectric. If desired, portions of housing  12  that have been separated from each other (e.g., by a through slot) may be joined by internal conductive structures (e.g., sheet metal or other metal members that bridge the slot). 
     Housing  12  may include peripheral housing structures such as peripheral structures  12 W. Peripheral structures  12 W and rear housing wall  12 R may sometimes be referred to herein collectively as conductive structures of housing  12 . Peripheral structures  12 W may run around the periphery of device  10  and display  14 . In configurations in which device  10  and display  14  have a rectangular shape with four edges, peripheral structures  12 W may be implemented using peripheral housing structures that have a rectangular ring shape with four corresponding edges and that extend from rear housing wall  12 R to the front face of device  10  (as an example). Peripheral structures  12 W or part of peripheral structures  12 W may serve as a bezel for display  14  (e.g., a cosmetic trim that surrounds all four sides of display  14  and/or that helps hold display  14  to device  10 ) if desired. Peripheral structures  12 W may, if desired, form sidewall structures for device  10  (e.g., by forming a metal band with vertical sidewalls, curved sidewalls, etc.). 
     Peripheral structures  12 W may be formed of a conductive material such as metal and may therefore sometimes be referred to as peripheral conductive housing structures, conductive housing structures, peripheral metal structures, peripheral conductive sidewalls, peripheral conductive sidewall structures, conductive housing sidewalls, conductive sidewalls, peripheral conductive housing sidewalls, sidewalls, sidewall structures, or a peripheral conductive housing member (as examples). Conductive sidewalls  12 W may be formed from a metal such as stainless steel, aluminum, or other suitable materials. One, two, or more than two separate structures may be used in forming conductive sidewalls  12 W. 
     It is not necessary for conductive sidewalls  12 W to have a uniform cross-section. For example, the top portion of peripheral conductive housing structures  12 W may, if desired, have an inwardly protruding lip (e.g., a ledge or datum) that helps hold display  14  in place. The bottom portion of conductive sidewalls  12 W may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). Conductive sidewalls  12 W may be substantially straight vertical sidewalls, may have curved portions, or may have other suitable shapes. 
     If desired, rear housing wall  12 R may be formed from a metal such as stainless steel or aluminum and may sometimes be referred to herein as conductive rear housing wall  12 R or conductive rear wall  12 R. Conductive rear housing wall  12 R may lie in a plane that is parallel to display  14 . In configurations for device  10  in which rear housing wall  12 R is formed from metal, it may be desirable to form parts of conductive sidewalls  12 W as integral portions of the housing structures forming the conductive rear housing wall of housing  12 . For example, conductive rear housing wall  12 R of device  10  may be formed from a planar metal structure and portions of conductive sidewalls  12 W on the sides of housing  12  may be formed as flat or curved vertically extending integral metal portions of the planar metal structure (e.g., housing structures  12 R and  12 W may be formed from a continuous piece of metal in a unibody configuration). Housing structures such as these may, if desired, be machined from a block of metal and/or may include multiple metal pieces that are assembled together to form housing  12 . Conductive rear housing wall  12 R may have one or more, two or more, or three or more portions. 
     Conductive sidewalls  12 W and/or the conductive rear housing wall  12 R may form one or more exterior surfaces of device  10  (e.g., surfaces that are visible to a user of device  10 ) and/or may be implemented using internal structures that do not form exterior surfaces of device  10  (e.g., conductive housing structures that are not visible to a user of device  10  such as conductive structures that are covered with layers such as thin cosmetic layers, protective coatings, and/or other coating layers that may include dielectric materials such as glass, ceramic, plastic, or other structures that form the exterior surfaces of device  10  and/or serve to hide structures  12 W and/or  12 R from view of the user). 
     Display  14  may have an array of pixels that form an active area AA that displays images for a user of device  10 . For example, active area AA may include an array of display pixels. The array of pixels may be formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma display pixels, an array of organic light-emitting diode display pixels or other light-emitting diode pixels, an array of electrowetting display pixels, or display pixels based on other display technologies. If desired, active area AA may include touch sensors such as touch sensor capacitive electrodes, force sensors, or other sensors for gathering a user input. 
     Display  14  may have an inactive border region that runs along one or more of the edges of active area AA. Inactive area IA may be free of pixels for displaying images and may overlap circuitry and other internal device structures in housing  12 . To block these structures from view by a user of device  10 , the underside of the display cover layer or other layers in display  14  that overlap inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, transparent ceramic, sapphire, or other transparent crystalline material, or other transparent layer(s). The display cover layer may have a planar shape, a convex curved profile, a shape with planar and curved portions, a layout that includes a planar main area surrounded on one or more edges with a portion that is bent out of the plane of the planar main area, or other suitable shapes. The display cover layer may cover the entire front face of device  10 . In another suitable arrangement, the display cover layer may cover substantially all of the front face of device  10  or only a portion of the front face of device  10 . Openings may be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button. An opening may also be formed in the display cover layer to accommodate ports such as speaker port  8  or a microphone port. Openings may be formed in housing  12  to form communications ports (e.g., an audio jack port, a digital data port, etc.) and/or audio ports for audio components such as a speaker and/or a microphone if desired. 
     Display  14  may include conductive structures such as an array of capacitive electrodes for a touch sensor, conductive lines for addressing pixels, driver circuits, etc. Housing  12  may include internal conductive structures such as metal frame members and a planar conductive housing member (sometimes referred to as a backplate or midplate) that spans the walls of housing  12  (i.e., a substantially rectangular sheet formed from one or more metal parts that is welded or otherwise connected between opposing sides of conductive sidewalls  12 W). Device  10  may also include conductive structures such as printed circuit boards, components mounted on printed circuit boards, and other internal conductive structures. These conductive structures, which may be used in forming a ground plane in device  10 , may extend under active area AA of display  14 , for example. 
     In regions  16  and  20 , openings may be formed within the conductive structures of device  10  (e.g., between conductive sidewalls  12 W and opposing conductive ground structures such as conductive portions of conductive rear housing wall  12 R, conductive traces on a printed circuit board, conductive electrical components in display  14 , etc.). These openings, which may sometimes be referred to as gaps or slots, may be filled with air, plastic, and/or other dielectrics and may be used in forming slot antenna resonating elements for one or more antennas in device  10 , if desired. 
     Conductive housing structures and other conductive structures in device  10  may serve as a ground plane for the antennas in device  10 . The openings in regions  20  and  16  may serve as slots in open or closed slot antennas, may serve as a central dielectric region that is surrounded by a conductive path of materials in a loop antenna, may serve as a space that separates an antenna resonating element such as a strip antenna resonating element or an inverted-F antenna resonating element from the ground plane, may contribute to the performance of a parasitic antenna resonating element, or may otherwise serve as part of antenna structures formed in regions  20  and  16 . If desired, the ground plane that is under active area AA of display  14  and/or other metal structures in device  10  may have portions that extend into parts of the ends of device  10  (e.g., the ground may extend towards the dielectric-filled openings in regions  20  and  16 ), thereby narrowing the slots in regions  20  and  16 . 
     In general, device  10  may include any suitable number of antennas (e.g., one or more, two or more, three or more, four or more, etc.). The antennas in device  10  may be located at opposing first and second ends of an elongated device housing (e.g., at ends  20  and  16  of device  10  of  FIG. 1 ), along one or more edges of a device housing, in the center of a device housing, in other suitable locations, or in one or more of these locations. The arrangement of  FIG. 1  is merely illustrative. 
     Portions of conductive sidewalls  12 W may be provided with peripheral gap structures. For example, conductive sidewalls  12 W may be provided with one or more gaps such as gaps  18 , as shown in  FIG. 1 . The gaps in peripheral conductive sidewalls  12 W may be filled with dielectric such as polymer, ceramic, glass, air, other dielectric materials, or combinations of these materials. Gaps  18  may divide conductive sidewalls  12 W into one or more peripheral conductive segments. There may be, for example, two peripheral conductive segments in conductive sidewalls  12 W (e.g., in an arrangement with two of gaps  18 ), three peripheral conductive segments (e.g., in an arrangement with three of gaps  18 ), four peripheral conductive segments (e.g., in an arrangement with four of gaps  18 ), six peripheral conductive segments (e.g., in an arrangement with six gaps  18 ), etc. The segments of conductive sidewalls  12 W that are formed in this way may form parts of antennas in device  10 . 
     If desired, openings in housing  12  such as grooves that extend partway or completely through housing  12  may extend across the width of rear wall  12 R of housing  12  and may penetrate through the rear wall of housing  12  to divide the rear wall into different portions. These grooves may also extend into conductive sidewalls  12 W and may form antenna slots, gaps  18 , and other structures in device  10 . Polymer or other dielectric may fill these grooves and other housing openings. In some situations, housing openings that form antenna slots and other structure may be filled with a dielectric such as air. 
     In a typical scenario, device  10  may have one or more upper antennas and one or more lower antennas (as an example). An upper antenna may, for example, be formed at the upper end of device  10  in region  16 . A lower antenna may, for example, be formed at the lower end of device  10  in region  20 . The antennas may be used separately to cover identical communications bands, overlapping communications bands, or separate communications bands. The antennas may be used to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme. 
     In order to provide an end user of device  10  with as large of a display as possible (e.g., to maximize an area of the device used for displaying media, running applications, etc.), it may be desirable to increase the amount of area at the front face of device  10  that is covered by active area AA of display  14 . Increasing the size of active area AA may reduce the size of inactive area IA within device  10 . This may reduce the area of regions  20  and  16  that is available for forming antennas within device  10 . In general, antennas that are provided with larger operating volumes or spaces may have higher bandwidth efficiency than antennas that are provided with smaller operating volumes or spaces. If care is not taken, increasing the size of active area AA may reduce the operating space available to the antennas, which can undesirably inhibit the efficiency bandwidth of the antennas (e.g., such that the antennas no longer exhibit satisfactory radio-frequency performance). It would therefore be desirable to be able to provide antennas that occupy a small amount of space within device  10  (e.g., to allow for as large of a display active area AA as possible) while still allowing the antennas to operate with optimal efficiency bandwidth. 
     A schematic diagram of device  10  is shown in  FIG. 2 . As shown in  FIG. 2 , transceiver circuitry  90  in wireless circuitry  34  may be coupled to antenna structures such as antenna  40  using paths such as path  92 . Wireless circuitry  34  may be coupled to control circuitry  28 . Control circuitry  28  may be storage and processing circuitry that includes storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in circuitry  28  may be used to control the operation of device  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, application specific integrated circuits, etc. 
     Control circuitry  28  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications, operating system functions, etc. To support interactions with external equipment, circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using storage and processing circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as Wi-Fi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, multiple-input and multiple-output (MIMO) protocols, antenna diversity protocols, etc. 
     Control circuitry  28  may be coupled to input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, cameras, buttons, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, position and orientation sensors (e.g., sensors such as accelerometers, gyroscopes, and compasses), capacitance sensors, proximity sensors (e.g., capacitive proximity sensors, light-based proximity sensors, etc.), fingerprint sensors (e.g., a fingerprint sensor integrated with a button or a fingerprint sensor that takes the place of a button), etc. 
     To provide antenna structures such as antenna(s)  40  with the ability to cover communications frequencies of interest, antenna(s)  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna(s)  40  may be provided with adjustable circuits to tune antennas over communications bands of interest. 
     Path  92  may include one or more transmission lines. As an example, signal path  92  of  FIG. 2  may be a transmission line having a positive signal conductor such as line  94  and a ground signal conductor such as line  96 . Lines  94  and  96  may form parts of a coaxial cable or a microstrip transmission line (as examples). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna(s)  40  to the impedance of transmission line  92 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna(s)  40  and may be tunable and/or fixed components. 
     Transmission line  92  may be coupled to antenna feed structures associated with antenna  40 . As an example, antenna  40  may be formed from an antenna resonating element such as antenna resonating element  104  and an antenna ground such as antenna ground  102  (sometimes referred to herein as ground plane  102 ). Antenna resonating element  104  and antenna ground  102  may be used to form an inverted-F antenna, a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground transmission line conductor  96  may be coupled to ground antenna feed terminal  100 . Other types of antenna feed arrangements may be used if desired. For example, antenna structures  40  may be fed using multiple feeds. The illustrative feeding configuration of  FIG. 2  is merely illustrative. 
     As shown in  FIG. 2 , input-output devices  32  include display  14 . Display  14  may include a display module that is covered by a transparent display cover layer. The display module may include stacked dielectric layers having pixel circuitry, touch sensor electrodes, force sensor circuitry, and/or other active components associated with emitting light and/or receiving input through the display cover layer. The display module may include conductive display structures such as conductive display structures  110  of  FIG. 3 . 
     Conductive display structures  110  may include a conductive frame for the active components of display  14 , conductive layers in the display module (e.g., a conductive backplate for the display module or conductive layers embedded within the dielectric layers of the display module), conductive shielding structures, ground layers in display  14 , and/or other conductive structures in display  14 . If desired, conductive display structures  110  may include portions of the pixel circuitry, touch sensor circuitry, force sensor circuitry, and/or other components in the display module for display  14 . Conductive display structures  110  may laterally extend across active area AA of  FIG. 1 , for example. As active area AA of display  14  is maximized, the space within device  10  occupied by the display module and conductive display structures  110  are also maximized, thereby limiting the amount of space available within device  10  for forming antennas  40 . 
       FIG. 3  is a top-down view of device  10  showing different regions of device  10  that can be used to form antennas  40 . The display cover layer of display  14  is omitted from the example of  FIG. 3  for the sake of clarity. As shown in  FIG. 3 , conductive display structures  110  may be separated from conductive sidewalls  12 W by gaps  112 . Gaps  112  may, for example, define inactive area IA of display  14  ( FIG. 1 ). 
     Antennas  40  ( FIG. 2 ) may be formed within one or more regions  114  of  FIG. 3 . Regions  114  may be located within region  16  at the upper end of device  10 , within region  20  at the lower end of device  10 , and/or at locations between the ends of device  10 . In one suitable arrangement, different antennas  40  may be formed within different regions  114  at each of the corners of device  10 . Each region  114  may include multiple antennas if desired. In general, device  10  may include any desired number of antennas  40  formed within any desired number of regions  114  at any desired locations around the periphery of device  10 . 
     Conductive sidewalls  12 W may be used in forming antenna ground  102  and/or antenna resonating element  104  ( FIG. 2 ) for the antennas  40  within regions  114 . For example, conductive sidewalls  12 W may be separated from conductive rear housing wall  12 R ( FIG. 1 ) within regions  114  by one or more dielectric slots. Antenna feed terminals  98  and  100  of  FIG. 2  may be coupled across these slots to feed antennas  40  (e.g., antenna feed terminal  98  or  100  may be coupled to conductive sidewall  12 W whereas the other antenna feed terminal is coupled to conductive rear housing wall  12 R on an opposing side of the slot). This may establish an aperture (volume) for each antenna that supports electromagnetic radiation within one or more desired frequency bands. 
     In practice, conductive display structures  110  may overlap and/or may be in close proximity to the antenna apertures within regions  114 . Conductive display structures  110  over or near to the antenna apertures may serve to block some of the radio-frequency signals conveyed by the antennas, particularly through display  14 . This can reduce the efficiency and bandwidth of the antennas through the front face of device  10 . 
     In order to mitigate these effects, conductive display structures  110  may be coupled to ground (e.g., antenna ground  102  of  FIG. 2 ) at one or more locations overlapping each antenna aperture (e.g., within regions  114  of  FIG. 3 ). Conductive grounding structures such as conductive grounding structures  116  may be used to couple conductive display structures  110  to conductive sidewalls  12 W at one or more locations within each region  114  (e.g., overlapping each antenna aperture). Conductive grounding structures  116  may have a first terminal coupled to conductive sidewalls  12 W and a second terminal coupled to conductive display structures  110  (e.g., conductive grounding structures  116  may bridge gap  112  and may overlap the antenna aperture for a corresponding antenna  40 ). This may couple the portion of conductive display structures  110  adjacent to each antenna aperture to a ground potential (e.g., antenna ground  102  of  FIG. 2 ), thereby allowing radio-frequency signals for the antennas to pass through display  14  without being substantially blocked by conductive display structures  110 . 
     Grounding structures  116  may overlap any desired locations within the antenna  40  of each region  114 . As examples, grounding structures  116  may overlap an antenna return path, antenna tuning element, antenna feed terminals, antenna resonating element arms, and/or other portions of each antenna  40 . Conductive display structures  110  may be coupled to conductive sidewalls  12 W by multiple grounding structures  116  if desired (e.g., multiple grounding structures  116  may be formed within each region  114 ). 
     Grounding structures  116  may each include conductive wire, sheet metal, conductive foam, conductive adhesive, welds, solder, conductive springs, conductive pins, conductive tape, and/or any other desired conductive structures.  FIG. 4  is a cross-sectional side view of device  10  (e.g., as taken along line AA′ of  FIG. 3 ) in an example where grounding structures  116  include conductive tape. 
     As shown in  FIG. 4 , display  14  may include display cover layer  120  mounted to conductive display structures  110  (e.g., conductive display structures  110  may be mounted to inner surface  124  of display cover layer  120 ). Display cover layer  120  may be transparent and may be formed from any desired materials such as glass, plastic, or sapphire. Portions of display cover layer  120  may be provided with an opaque masking layer such as an ink layer if desired. 
     Display  14  may be mounted to conductive sidewalls  12 W. Conductive sidewalls  12 W may be separated from conductive rear housing wall  12 R by gap  141 . Dielectric material may be placed within gap  141  and may lie flush with the exterior surface of device  10 . Conductive sidewall  12 W may have an inwardly-protruding portion (extension)  140  that is sometimes referred to herein as ledge  140  or datum  140 . Ledge  140  may have a lateral surface that extends parallel to inner surface  124  of display cover layer  120 . Display  14  may be secured to conductive sidewall  12 W by coupling display cover layer  120  to ledge  140  using adhesive material. 
     Antenna  40  may be formed from conductive rear housing wall  12 R and conductive sidewall  12 W. For example, antenna terminals  98  and  100  of antenna  40  ( FIG. 2 ) may be coupled to conductive rear housing wall  12 R and conductive sidewall  12 W on opposing sides of gap  141 . Gap  141  (sometimes referred to herein as slot  141 ) may form a slot antenna resonating element for antenna  40 , as one example. The lateral area of gap  141  (e.g., within the X-Y plane of  FIG. 4 ) may define part of the antenna aperture for antenna  40 . Gap  141  may extend parallel to the Y-axis of  FIG. 4  and may have an elongated length that helps to define the resonating frequency of antenna  40 . Gap  141  may extend up the height of an adjacent conductive sidewall  12 W if desired (e.g., gap  141  and gaps such as gap  18  of  FIG. 1  may be formed from a single continuous dielectric-filled gap extending along multiple sides of device  10 ). 
     In the absence of conductive grounding structures, the presence of conductive display structures  110  in the vicinity of antenna  40  may limit antenna efficiency and bandwidth through display cover layer  120 . Grounding structures  116  may couple conductive display structures  110  to conductive housing wall  12 W to maximize antenna efficiency and bandwidth through display cover layer  120 . As shown in  FIG. 4 , grounding structures  116  may include conductive tape structures such as conductive tape  132 . 
     Conductive tape  132  may include a layer of conductive material having a first lateral surface  126  and an opposing second lateral surface  130 . A layer of adhesive material such as heat-activated, pressure-sensitive adhesive may be provided on surface  126  and/or surface  130  of conductive tape  132 . In the example of  FIG. 4 , a layer of adhesive is provided on surface  126  of conductive tape  132  whereas surface  130  is free from adhesive. Surface  126  may therefore sometimes be referred to herein as adhesive surface  126  whereas surface  130  is sometimes referred to herein as non-adhesive surface  130 . The conductive material in conductive tape  132  may include copper, gold, and/or other metals. 
     Conductive tape  132  may have a first end  128  that is mechanically and electrically coupled to conductive display structures  110  and a second end  148  that is mechanically and electrically coupled to ledge  140  of conductive sidewall  12 W. As shown in  FIG. 4 , adhesive surface  126  at end  128  of conductive tape  132  may be attached to conductive display structures  110 . If desired, adhesive surface  126  may additionally or alternatively be coupled to the side of conductive display structures  110 . Adhesive surface  126  may also be attached to inner surface  124  of display cover layer  120 . 
     When display  14  is mounted to conductive sidewall  12 W, a vertical portion  142  of conductive sidewall  12 W may extend around the lateral periphery of display cover layer  120 . Exterior surface  122  of display cover layer  120  may lie flush with top surface  144  of conductive sidewall  12 W (e.g., top surface  144  of vertical portion  142  of conductive sidewall  12 W). In practice, it can be difficult to ensure that exterior surface  122  of display cover layer  120  lies flush with top surface  144  of conductive sidewall  12 W. For example, the thickness of conductive tape  132  may be less than the vertical distance between top surface  144  and ledge  140  and manufacturing variations in conductive sidewall  12 W and display cover layer  120  can make it difficult to produce a large quantity of electronic devices  10  having uniform exterior surfaces. 
     In order to mitigate these difficulties, end  148  of conductive tape  132  may be wrapped around a layer of heat-activated film such as heat-activated film  134 . For example, heat-activated film  134  may be coupled to non-adhesive surface  130  of conductive tape  132 . End  148  of conductive tape  132  may be wrapped around axis  143  such that heat-activated film  134  is interposed between parallel portions  147  and  146  of conductive tape  132 . Adhesive surface  126  within portion  147  of conductive tape  132  may be attached to inner surface  124  of display cover layer  120 . Adhesive surface  126  within portion  146  of conductive tape  132  may be attached to ledge  140 . 
     Heat-activated film  134  may be deformable (compressible) when heated above a predetermined activation temperature and may retain a deformed (compressed) shape after cooling below the activation temperature. During assembly of device  10 , heat-activated film  134  may be heated above the activation temperature and display cover layer  120  may be pressed downward onto conductive sidewall  12 W (e.g., in the direction of arrow  152 ) until exterior surface  122  lies flush with top surface  144  of conductive sidewall  12 W. Heat-activated film  134  may then be cooled below the activation temperature so that display cover layer  120  is locked in place (e.g., while surface  122  is flush with surface  144 ). In this way, surface  122  may lie flush with surface  144  in the fully-assembled device  10  regardless of any manufacturing variations in display  14  and conductive sidewall  12 W. 
     Once heat-activated film  134  has been cooled, adhesive surface  126  of conductive tape  132  may adhere display cover layer  120  to conductive sidewall  12 W. At the same time, conductive tape  132  may hold conductive display structures  110  at a ground potential by electrically coupling conductive display structures  110  to antenna ground  102  ( FIG. 2 ) through conductive sidewall  12 W. By grounding conductive display structures  110  over the aperture for antenna  40  (e.g., at a location overlapping slot  141 ), antenna  40  may radiate radio-frequency signals through display cover layer  120  without being blocked by conductive display structures  110  (e.g., with satisfactory antenna efficiency and bandwidth). 
     If desired, heat-activated film  134  may be offset from end  148  of conductive tape  132  by distance  138 . This may allow room for heat-activated film  134  to expand (as shown by arrow  136 ) when display cover layer  120  is pressed onto ledge  140  (e.g., without spilling into the interior of device  10 ). The example of  FIG. 4  is merely illustrative. If desired, conductive tape  132  may have other shapes and may follow other paths (e.g., paths conforming to the shape of other components within device  10 ). Conductive sidewall  12 W may have other cross-sectional shapes. Other adhesive materials such as pressure-sensitive adhesive may be used in place of heat-activated film  134  if desired. 
     If desired, additional adhesive material may be used to help secure display  14  to conductive sidewall  12 W (e.g., to ensure a reliable attachment between display cover layer  120  and ledge  140 ).  FIG. 5  is a top-down view (e.g., in the direction of arrow  152  of  FIG. 4 ) showing how additional adhesive material may be used to attach display cover layer  120  to ledge  140 . 
     In the example of  FIG. 5 , display cover layer  120  has been omitted for the sake of clarity. As shown in  FIG. 5 , a layer of adhesive such as adhesive  150  may be attached to ledge  140  of conductive sidewall  12 W. Vertical portion  142  of conductive sidewall  12 W may extend vertically (e.g., parallel to the Z-axis) beyond the top lateral surface of adhesive  150 . Adhesive  150  may be, for example, pressure-sensitive adhesive that is activated by pressing display cover layer  120  onto conductive sidewalls  12 W and/or by heating. Adhesive  150  is sometimes referred to herein as pressure-sensitive  150  for the sake of simplicity. In practice, adhesive  150  may additionally or alternatively be activated by heat and may sometimes be referred to herein as heat-activated, pressure-sensitive adhesive  150  or heat-activated adhesive  150 . 
     Pressure-sensitive adhesive  150  may include a notch or gap  153 . Conductive tape  132  may be attached to ledge  140  of conductive sidewall  12 W within notch  153  of pressure-sensitive adhesive  150 . In this way, pressure-sensitive adhesive  150  may enhance the mechanical attachment between display cover layer  120  and conductive sidewall  12 W while also accommodating conductive tape  132 . Conductive tape  132  may serve to both help adhere display cover layer  120  to conductive sidewall  12 W and to ground conductive display structures  110  ( FIG. 4 ). 
       FIGS. 6 and 7  are cross-sectional side views of conductive tape  132  and pressure-sensitive adhesive  150  (e.g., as taken in the direction of arrow  154  of  FIG. 5  or arrow  149  of  FIG. 4 ). In the example of  FIG. 6 , pressure-sensitive adhesive  150  and conductive tape  132  have been attached to display cover layer  120  but have not yet been attached to conductive sidewall  12 W. As shown in  FIG. 6 , conductive tape  132  and heat-activated film  134  may have a vertical thickness  158  (e.g., with respect to display cover layer  120 ) that is greater than the vertical thickness of pressure-sensitive adhesive  150  by distance  160 . When heat-activated film  134  is heated, display cover layer  120  may be pressed onto ledge  140  and heat-activated film  134  may be compressed, as shown by arrow  156 . This may allow display cover layer  120  to be mounted to conductive sidewall  12 W such that exterior surface  122  lies flush with top surface  144  of conductive sidewall  12 W (e.g., as shown in  FIG. 4 ) regardless of potential manufacturing variations. 
     In the example of  FIG. 7 , pressure-sensitive adhesive  150  and conductive tape  132  have been attached to ledge  140  of conductive sidewall  12 W. Heat-activated film  134  has been compressed as necessary for portion  146  of conductive tape  132  to lie flush with the bottom surface of pressure-sensitive adhesive  150  at ledge  140 . Heat-activated film  134  holds this compressed configuration after cooling. Portion  147  of conductive tape  132  may be adhered to display cover layer  120  whereas portion  146  of conductive tape  132  is adhered to ledge  140 . Conductive tape  132  of  FIGS. 4-7  may be used to form grounding structures  116  for each antenna  40  in device  10  if desired (e.g., within one or more regions  114  of  FIG. 3 ). 
     The example of  FIGS. 4-7  in which grounding structures  116  include conductive tape are merely illustrative. In another suitable arrangement, end  148  of conductive tape  132  may be un-folded. In this arrangement, conductive tape  132  may include a planar end that extends between display cover layer  120  and ledge  140  (e.g., a portion of conductive tape  132  may be interposed between display cover layer  120  and ledge  140 ). In this scenario, the layer of pressure-sensitive adhesive (e.g., pressure-sensitive adhesive  150  of  FIGS. 5-7  or heat-activated, pressure sensitive adhesive) may be formed without notch  153  ( FIG. 5 ) and may extend over conductive tape  132  to adhere conductive tape  132  (and conductive sidewall  12 W) to display cover layer  120  (e.g., the pressure-sensitive adhesive may be interposed between the portion of conductive tape  132  coupled to ledge  140  and display cover layer  120 ). 
     If desired, grounding structures  116  may include an air loop gasket.  FIG. 8  is a cross-sectional side view of device  10  (e.g., as taken along line AA′ of  FIG. 3 ) in an example where conductive grounding structures  116  include an air loop gasket. 
     As shown in  FIG. 8 , grounding structures  116  may include conductive tape  176  coupled to conductive display structures  110  and inner surface  124  of display cover layer  120 . A conductive gasket such as conductive gasket  174  may be coupled to conductive tape  176 . Conductive gasket  174  may include conductive fabric wrapped around an air cavity or any other desired gasket structures. In one suitable arrangement, conductive gasket  174  may include a Mylar-enforced air loop gasket or other types of air loop gasket (e.g., a gasket having a conductive fabric surrounding an air cavity, a Mylar stiffener attached to portions of the conductive fabric, and foam within portions of the air cavity). 
     Conductive gasket  174  may be coupled to conductive sidewall  12 W via pressure-sensitive adhesive  172 . A layer of pressure-sensitive adhesive such as pressure-sensitive adhesive  170  may be used to attach display cover layer  120  to ledge  140 . Display cover layer  120  may be adhered to conductive sidewall  12 W through pressure-sensitive adhesive  170  and through conductive tape  176 , conductive gasket  174 , and pressure-sensitive adhesive  172 . 
     Conductive display structures  110  may be electrically coupled to conductive sidewall  12 W via conductive tape  176  and conductive gasket  174 . This may couple conductive display structures  110  to the antenna ground to help optimize efficiency and bandwidth through display cover layer  120  for antenna  40 . However, in practice, conductive tape of the type shown in  FIGS. 4-7  may optimize antenna efficiency and bandwidth more than the conductive gasket of  FIG. 8  because conductive tape  132  is grounded to conductive sidewall  12 W at a location overlapping the antenna aperture (e.g., overlapping gap  141  of  FIG. 4 ). 
     In another suitable arrangement, grounding structures  116  may include a conductive spring.  FIG. 9  is a cross-sectional side view of device  10  (e.g., as taken along line AA′ of  FIG. 3 ) in an example where conductive grounding structures  116  include a conductive spring. 
     As shown in  FIG. 9 , grounding structures  116  may include conductive tape  180  coupled to conductive display structures  110  and inner surface  124  of display cover layer  120 . A conductive spring such as conductive spring finger  182  may be coupled to conductive tape  180 . Conductive spring finger  182  may be coupled to conductive housing  12 W using one or more welds  184 . Conductive spring finger  182  may be biased against conductive tape  180  (e.g., conductive spring finger  182  may apply a spring force against tape  180  as shown by arrow  186 ). This may help to maintain a mechanical and electrical connection between conductive spring finger  182  and conductive tape  180  over time. 
     A layer of pressure-sensitive adhesive such as pressure-sensitive adhesive  188  may be used to attach display cover layer  120  to ledge  140 . Display cover layer  120  may be adhered to conductive sidewall  12 W through pressure-sensitive adhesive  188 . Conductive display structures  110  may be electrically coupled to conductive sidewall  12 W via conductive tape  180  and conductive spring finger  182 . This may electrically couple conductive display structures  110  to the antenna ground to help optimize efficiency and bandwidth through display cover layer  120  for antenna  40 . Forming grounding structure  116  using conductive spring finger  182  may simplify the manufacture of device  10  relative to the arrangements of  FIGS. 4-8 , for example. However, in practice, force  186  provided by conductive spring finger  182  against conductive tape  180  can leave display cover  120  more susceptible to delamination than the arrangements of  FIGS. 4-8 . 
     The examples of  FIGS. 4-9  are merely illustrative. Combinations of the grounding arrangements in  FIGS. 4-9  may be used if desired. In one suitable arrangement, grounding structures  116  may include conductive traces printed onto inner surface  124  of display cover layer  120  (e.g., the portion of conductive tape  132  of  FIG. 4 , conductive tape  176  of  FIG. 8 , or conductive tape  180  of  FIG. 9  that is in contact with inner surface  124  may be formed from conductive traces printed onto inner surface  124 ). 
     Forming grounding structures  116  using conductive tape  132  of  FIGS. 4-7  may allow grounding structures for each antenna  40  in device  10  to be assembled simultaneously and during the same process that is used to attach display  14  to conductive sidewalls  12 W. This may, for example, reduce process variations antenna-to-antenna and may help to ensure that exterior surface  122  of display cover layer  120  lies flush with top surface  144  of conductive sidewalls  12 W at all points along the front face of device  10 . This may also serve to limit device-to-device variations when assembling large quantities of electronic devices such as electronic device  10 . 
       FIG. 10  is a flow chart of illustrative steps that may be performed in assembling display  14  to conductive sidewalls  12 W (e.g., to concurrently attach grounding structures  116  for each of the antennas  40  in device  10  during the same manufacturing process that is used to attach display  14  to conductive sidewalls  12 W). The steps of  FIG. 10  may, for example, be performed using manufacturing and assembly equipment (e.g., during assembly/manufacture of electronic device  10 ). 
     At step  200 , display  14  may be assembled by mounting the display module (e.g., conductive display structures  110  of  FIG. 4 ) to display cover layer  120 . 
     At step  202 , pressure-sensitive adhesive  150  (e.g., a layer of heat-activated, pressure sensitive adhesive material) and conductive tape  132  for each antenna  40  (e.g., for each region  114  of  FIG. 3 ) may be attached to a dielectric substrate such as a dielectric liner. The dielectric liner may include openings for aligning to alignment posts in an assembly fixture. 
     At step  204 , display  14  may be mounted to an assembly fixture. The assembly fixture may include alignment posts. 
     At step  206 , the dielectric liner may be aligned with display  14  in the assembly fixture. The alignment holes in the dielectric liner may be placed over the alignment posts of the assembly fixture to align the dielectric liner with display  14 . When aligned, the pressure-sensitive adhesive and conductive tape on the dielectric liner may be aligned with the desired locations of grounding structures  116  for each antenna  40  in device  10  (e.g., for each region  114  of  FIG. 3 ). 
     At step  208 , the dielectric liner may be pressed onto display  14  in the assembly fixture. Pressure-sensitive adhesive (PSA)  150  and conductive tape  132  may be adhered to display  14 . The dielectric liner may be removed, leaving pressure-sensitive adhesive  150  and conductive tape  132  attached to display  14 . 
     At step  210 , display  14  (e.g., with pressure-sensitive adhesive  150  and conductive tape  132 ) may be flipped and placed over conductive sidewalls  12 W. Display  14  may be pressed onto ledge  140  of conductive sidewalls  12 W using a heat press. The heat press may apply pressure that activates the pressure-sensitive adhesive to secure display cover layer  120  to ledge  140 . The heat press may include heated press heads that are aligned with the locations of conductive tape  132  on display cover layer  120 . The heated press heads may heat film  134  on each instance of conductive tape  132  attached to display  14  so that film  134  becomes deformable. The press heads may then press down on conductive tape  132  until exterior surface  122  of display cover layer  120  lies flush with top surface  144  of conductive sidewalls  12 W. By pressing on the conductive tape for each antenna simultaneously (e.g., using the same heat press), surface  122  of display cover layer  120  may be aligned with top surface  144  of conductive sidewall  12 W across device  10  with greater precision than in scenarios where the conductive tape for each antenna is heated and pressed in series. 
     At step  212 , heat-activated film  134  is cooled, locking (fixing) display  14  in place on conductive sidewall  12 W. Device  10  may be removed from the assembly fixture. Additional device assembly may be performed if desired. The example of  FIG. 10  is merely illustrative. Steps  200 - 212  may be performed in any desired order. Two or more of steps  200 - 212  may be performed concurrently if desired. 
       FIGS. 11A and 11B  show a diagram of an illustrative assembly process for electronic device  10  (e.g., using the steps of  FIG. 10 ). As shown in  FIG. 11A , assembly fixture  220  in manufacturing system  218  may include one or more alignment posts  222 . Conductive structures  110  of display  14  may be mounted to display cover layer  120  (e.g., while processing step  200  of  FIG. 10 ). Display cover layer  120  and the attached conductive structures  110  may be mounted to assembly fixture  220  (e.g., while processing step  204  of  FIG. 10 ). 
     Dielectric liner  224  in manufacturing system  218  may include one or more alignment holes such as alignment holes  226 . Pressure-sensitive adhesive  150  and conductive tape  132  for each antenna  40  may be mounted to dielectric liner  224  (e.g., while processing step  202  of  FIG. 10 ). In the example of  FIGS. 11A and 11B , device  10  includes two antennas and two conductive tapes  132 - 1  and  132 - 2  are mounted to dielectric liner  224  (e.g., one for each antenna). Two or more conductive tapes  132  may be used for each antenna if desired. 
     Dielectric liner  224  may be placed over assembly fixture  220  as shown by arrow  228 . Alignment posts  222  on assembly fixture  220  may pass through alignment holes  226  on dielectric liner  224  to place conductive tapes  132 - 1  and  132 - 2  over predetermined locations on display cover layer  120  (e.g., locations where antennas  40  in device  10  are to be formed, as shown by regions  114  of  FIG. 3 ). Dielectric liner  224  may be pressed downwards onto display cover layer  120  and conductive display structures  110 , as shown by arrows  230  (e.g., using press equipment in manufacturing system  218 ). This may attach adhesive surface  126  ( FIG. 4 ) of conductive tapes  132 - 1  and  132 - 2  and pressure-sensitive adhesive  150  to display cover layer  120  (e.g., while processing step  208  of  FIG. 10 ). Conductive tapes  132 - 1  and  132 - 2  may also be attached to conductive display structures  110 . Dielectric liner  224  may be removed from conductive tapes  132 - 1  and  132 - 2  and pressure-sensitive adhesive  150 , leaving behind conductive tapes  132 - 1  and  132 - 2  and pressure-sensitive adhesive  150  on display  14 . 
     As shown in  FIG. 11B , display  14 , the attached pressure-sensitive adhesive  150 , and the attached conductive tapes  132 - 1  and  132 - 2  may be flipped over and aligned with conductive sidewalls  12 W (e.g., within assembly fixture  220  or separate from assembly fixture  220  of  FIG. 11A ). Manufacturing system  218  may include heat press  242 . Heat press  242  may be coupled to controller  240 . Controller  240  may control heat press  242  to move in a particular direction and/or to heat one or more heated press heads  244  to a desired temperature. Heat press  242  may have a respective heated press head  244  for each conductive tape  132  on display  14 . In the example of  FIG. 11B , heat press  242  has a first heated press head  244 - 1  aligned with conductive tape  132 - 2  and a second heated press head  244 - 2  aligned with conductive tape  132 - 1 . 
     Controller  240  may control heat press  242  to press downwards onto display cover layer  120 , as shown by arrow  246 . This may serve to attach pressure-sensitive adhesive  150  to conductive sidewalls  12 W. Heated press head  244 - 1  may press down onto display cover layer  120  at the location of conductive tape  132 - 2 . Heated press head  244 - 2  may press down onto display cover layer  120  at the location of conductive tape  132 - 1 . Heated press heads  244 - 1  and  244 - 2  may be heated to a predetermined temperature greater than or equal to the activation temperature of heat-activated film  134  in conductive tapes  132 - 1  and  132 - 2  (e.g., 80 degrees Celsius, 90 degrees Celsius, between 70 and 95 degrees Celsius, etc.). This may activate heat-activated film  134  in conductive tapes  132 - 2  and  132 - 1  so that the heat-activated film becomes deformable (e.g., while processing step  210  of  FIG. 10 ). Pressure provided by press heads  244 - 1  and  244 - 2  may be adjusted to align exterior surface  122  of display cover layer  120  with top surface  144  of conductive sidewalls  12 W ( FIG. 4 ). 
     Press heads  244 - 1  and  244 - 2  of  FIG. 11B  may subsequently be removed so that the heat-activated film may cool. Once cooled, conductive tapes  132 - 1  and  132 - 2  may be adhered to conductive sidewalls  12 W and may have a fixed thickness such that exterior surface  122  of display cover layer  120  lies flush with top surface  144  of conductive sidewalls  12 W. As shown by arrow  250 , a fully assembled device  10  having display  14  mounted to housing  12  may be provided to an end user. The example of  FIGS. 11A and 11B  is merely illustrative. In general, any desired manufacturing processes may be used to assemble device  10 . Dielectric liner  224  of  FIG. 11A  may extend around multiple sides of display  14 . 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20180918
Publication Date: 20210202
Grant Date: 20210202
Priority Date: 20180918
Inventors: OSTER, Carli E.
ZHANG, CHI
Wang, Haowei
Compton, Lucas R.
Assignee: APPLE INC
CPC Classifications: [{"code": "G09F9/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0247", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/48", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1698", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1698", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/182", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1698", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 69773974