PATENT DOCUMENT

Publication Number: US-8947303-B2
Application Number: US-97358610-A
Country: US
Kind Code: B2

Title: Peripheral electronic device housing members with gaps and dielectric coatings

Abstract:
An electronic device such as a handheld device may have a rectangular housing with a rectangular periphery. A conductive peripheral housing member may run along the rectangular periphery and may surround the rectangular housing. Radio-frequency transceiver circuitry within the electronic device may be coupled to antenna structures for transmitting and receiving radio-frequency signals. The conductive peripheral housing member may form part of the antenna structures. A gap in the conductive peripheral housing member may be filled with dielectric. The conductive peripheral housing member may be configured to form a recess. The recess may have the shape of a rectangle, oval, diamond, or other shape that overlaps and is bisected by the gap. The recess may also have the shape of a groove that extends around the entire periphery of the housing. The dielectric in the recess may include one or more different materials such as clear and opaque polymers.

Claims:
What is claimed is: 
     
       1. An electronic device having a periphery, comprising:
 at least one antenna that is formed at least partly from a rectangular conductive peripheral housing member that runs along the periphery and has a gap, wherein the rectangular conductive peripheral housing member has a recess that overlaps the gap; 
 ground structures; 
 a first antenna feed connected to the rectangular conductive peripheral housing member; 
 a second antenna feed connected to the ground structures; and 
 a dielectric structure that is formed within the recess. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the rectangular conductive peripheral housing member has an exterior and an interior and wherein portions of the exterior form sidewalls for the recess. 
     
     
       3. The electronic device defined in  claim 1  wherein the dielectric structure comprises polymer. 
     
     
       4. The electronic device defined in  claim 3  wherein the recess and the dielectric structure have a rectangular shape on the exterior. 
     
     
       5. The electronic device defined in  claim 3  wherein the recess and the dielectric structure have an oval shape on the exterior. 
     
     
       6. The electronic device defined in  claim 3  wherein the recess has a shape selected from the group consisting of: rectangular, diamond, and oval, and wherein the gap bisects the shape. 
     
     
       7. The electronic device defined in  claim 1  wherein the dielectric structure comprises ceramic. 
     
     
       8. The electronic device defined in  claim 1  wherein the electronic device comprises a rectangular housing with a rectangular periphery, wherein the rectangular conductive peripheral housing member comprise a rectangular metal ring that surrounds the rectangular periphery, and wherein the recess comprises a groove that runs along substantially all of the rectangular periphery. 
     
     
       9. The electronic device defined in  claim 8  wherein the dielectric structure comprises a first layer of material that lines the groove and a second layer of material that coats the first layer of material and wherein the first and second layers of materials are formed from different materials. 
     
     
       10. The electronic device defined in  claim 9  wherein the second layer of material is clear. 
     
     
       11. The electronic device defined in  claim 10  wherein the groove has sidewalls and wherein the second layer of material covers the sidewalls. 
     
     
       12. The electronic device defined in  claim 8  wherein the rectangular conductive peripheral housing member comprises a plurality of gaps and wherein the groove and the dielectric structure within the groove overlaps each of the gaps. 
     
     
       13. The electronic device defined in  claim 1  wherein the rectangular conductive peripheral housing member comprises inwardly extending protrusions at the gap. 
     
     
       14. The electronic device defined in  claim 13  comprising a first dielectric material that bridges the protrusions and a second dielectric material that forms the dielectric structure. 
     
     
       15. The electronic device defined in  claim 12  wherein the first dielectric material comprises a glass-filled polymer and wherein the second dielectric material is free of glass. 
     
     
       16. The electronic device defined in  claim 1  wherein the rectangular conductive peripheral housing member has slanted surfaces that form a retention feature that holds the dielectric structure to the rectangular conductive peripheral housing member. 
     
     
       17. An electronic device, comprising:
 a radio-frequency transceiver; 
 antenna structures coupled to the radio-frequency transceiver; 
 a rectangular housing with a rectangular periphery, wherein the rectangular housing comprises a conductive peripheral housing member that runs along the rectangular periphery, wherein the conductive peripheral housing member comprises at least one dielectric-filled gap, and wherein the conductive peripheral housing member forms the antenna resonating element of the antenna structures; 
 ground structures; 
 a first antenna feed connected to the rectangular housing; 
 a second antenna feed connected to the ground structures; 
 a groove that extends along at least some of an exterior surface of the rectangular periphery; and 
 a dielectric that fills the groove and that overlaps the gap. 
 
     
     
       18. The electronic device defined in  claim 17  wherein the dielectric comprises a shrunken plastic ring. 
     
     
       19. The electronic device defined in  claim 17  wherein the dielectric comprises ceramic. 
     
     
       20. The electronic device defined in  claim 17  wherein the conductive peripheral housing member comprises portions that form sidewalls for the groove, wherein the groove extends around substantially all of the rectangular periphery, and wherein the dielectric includes at least one polymer. 
     
     
       21. The electronic device defined in  claim 17  wherein the dielectric comprises a first polymer in the groove and a second polymer in the groove, wherein the second polymer covers the first polymer. 
     
     
       22. An electronic device, comprising:
 a rectangular housing having a rectangular periphery; 
 a ring-shaped rectangular peripheral housing member that runs along the rectangular periphery and surrounds the rectangular housing, wherein the ring-shaped rectangular peripheral housing member has an interior, an exterior, a gap, and at least one groove in the exterior that overlaps the gap; 
 an antenna having an antenna resonating element formed from the ring-shaped rectangular peripheral housing member; 
 ground structures; 
 a first antenna feed connected to the ring-shaped rectangular peripheral housing member; and 
 a second antenna feed connected to the ground structures. 
 
     
     
       23. The electronic device defined in  claim 22  wherein the groove runs along the rectangular periphery and surrounds the rectangular housing. 
     
     
       24. The electronic device defined in  claim 23  further comprising dielectric within the groove. 
     
     
       25. The electronic device defined in  claim 24  wherein the dielectric comprises a plastic ring. 
     
     
       26. The electronic device defined in  claim 24  wherein the dielectric comprises an opaque polymer layer coated with a transparent polymer layer. 
     
     
       27. The electronic device defined in  claim 24  wherein the dielectric comprises a glass-free polymer and wherein the electronic device further comprises a glass-filled polymer interposed between protrusions on the ring-shaped peripheral housing member. 
     
     
       28. The electronic device defined in  claim 24  wherein the ring-shaped peripheral housing member comprises metal. 
     
     
       29. The electronic device defined in  claim 24  wherein the dielectric comprises ceramic. 
     
     
       30. Apparatus, comprising:
 a ring-shaped rectangular metal peripheral housing member configured to run along a rectangular periphery of a rectangular electronic device, wherein the ring-shaped rectangular metal peripheral housing member has an interior, an exterior, and has at least one groove in the exterior; 
 a dielectric within the groove; 
 an antenna having an antenna resonating element formed from a portion of the ring-shaped rectangular metal peripheral housing member; 
 ground structures; 
 a first antenna feed connected to the ring-shaped rectangular metal peripheral housing member; and 
 a second antenna feed connected to the ground structures, wherein the ring-shaped rectangular metal peripheral housing member has a gap and the groove overlaps the gap. 
 
     
     
       31. The apparatus defined in  claim 30  wherein the dielectric within the groove comprises a rectangular ring of polymer configured to run along the rectangular periphery. 
     
     
       32. The apparatus defined in  claim 30  wherein the dielectric comprises ceramic.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to housing members in electronic devices such as electronic devices with wireless communications circuitry. 
     Electronic devices such as portable computers and cellular telephones are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry such as cellular telephone circuitry to communicate using cellular telephone bands at 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz. Electronic devices may use short-range wireless communications links to handle communications with nearby equipment. For example, electronic devices may communicate using the WiFi® (IEEE 802.11) bands at 2.4 GHz and 5 GHz and the Bluetooth® band at 2.4 GHz. Satellite navigation system signals may be received in bands such as the Global Positioning System band at 1575 MHz. 
     To satisfy consumer demand for small form factor wireless devices, manufacturers are continually striving to implement wireless communications circuitry such as antenna components using compact structures. To address these concerns, some electronic devices use metal portions of a device housing in forming device antennas. 
     In antenna configurations such as these, it would be desirable to ensure that antenna operation is relatively immune to the influence of contact with the antenna structures. For example, antenna operation should be satisfactory even in the event that a user grasps an electronic device housing in a way that causes the user&#39;s hand to come into contact with the antenna structures. It may also be desirable to incorporate dielectric materials into device housing structures to enhance device aesthetics. 
     It would therefore be desirable to be able to provide improved housing structures for electronic devices such as electronic devices with antenna structures formed from device housing structures. 
     SUMMARY 
     An electronic device such as a handheld device may have a rectangular housing with a rectangular periphery. A peripheral housing member may run along the rectangular periphery and may surround the rectangular housing. The peripheral housing member may be formed from a conductive material such as metal. 
     The peripheral housing member may have a groove or other recess. The groove may run along the entirety of the peripheral housing member and may surround the rectangular housing. Recess shapes such as ovals, diamonds, and rectangles may be used for recesses that do not run around the entire rectangular housing. 
     Groove-shaped recesses and other recesses in the peripheral housing member may be filled with dielectric. The dielectric may include one or more polymers or other non-conductive materials. 
     Radio-frequency transceiver circuitry within the electronic device may be coupled to antenna structures for transmitting and receiving radio-frequency signals. The peripheral housing member may form part of the antenna structures. One or more gaps in the peripheral housing member may be filled with dielectric. The groove or other recess structures in the peripheral housing member may be configured to overlap the gaps. 
     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 with wireless communications circuitry in accordance with an embodiment of the present invention. 
         FIG. 2  is a top interior view of an illustrative electronic device with wireless communications circuitry that includes exposed antenna structures such as a conductive peripheral housing member with gaps in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional top view of a portion of a device housing showing how capacitance between a conductive peripheral housing member and an external object such as a finger of a user can be reduced by interposing a dielectric coating between the conductive peripheral housing member and the finger in accordance with an embodiment of the present invention. 
         FIG. 4  is cross-sectional side view of a conventional housing band member in contact with the finger of a user. 
         FIG. 5  is a cross-sectional side view of a conductive peripheral housing member with a dielectric coating in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of a conductive peripheral housing member with a dielectric coating in the vicinity of a gap in the conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 7  is a diagram of a chamber of the type that may be used in forming a dielectric coating for a conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of a conductive peripheral housing member that has an undercut shape to help retain a dielectric coating in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of a conductive peripheral housing member that has a groove with straight sides to receive a dielectric coating and a retention feature to help retain the dielectric coating in accordance with an embodiment of the present invention. 
         FIG. 10  is a side view of an illustrative conductive peripheral housing member having a groove that is filled with a dielectric coating in the vicinity of a gap in the conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 11  is a side view of an illustrative conductive peripheral housing member having a recess in the shape of a rectangular truncated groove that is filled with a dielectric coating in the vicinity of a gap in the conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 12  is a side view of an illustrative conductive peripheral housing member having an oval-shaped recess and dielectric patch that overlaps a portion of the conductive peripheral housing member that has a gap in accordance with an embodiment of the present invention. 
         FIG. 13  is a side view of an illustrative conductive peripheral housing member having a diamond-shaped recess and dielectric structure that overlaps a portion of the conductive peripheral housing member that has a gap in accordance with an embodiment of the present invention. 
         FIG. 14  is a side view of an illustrative conductive peripheral housing member with a dielectric structure having a shape with curved edges that overlaps a portion of the conductive peripheral housing member that has a gap in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional view of a conductive peripheral housing member having a dielectric coating that covers substantially all of the exterior surface of the conductive peripheral housing member and having a retention feature that helps ensure that the coating stays attached to the conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 16  is a cross-sectional view of a conductive peripheral housing member having multiple coating layers of materials such as dielectrics in accordance with an embodiment of the present invention. 
         FIG. 17  is a cross-sectional view of a conductive peripheral housing member that has a groove and that has multiple coating layers of materials such as dielectrics within the groove in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional view of a conductive peripheral housing member that has a groove and that has a coating layer that is received within the groove and another coating layer that covers substantially all of the exterior surface of the conductive peripheral housing member in accordance with an embodiment of the present invention. 
         FIG. 19  is a perspective view of a portion of a conductive peripheral housing member in the vicinity of a gap showing how multiple shots of dielectric material may be used in forming a dielectric coating patch and an internal structural member in accordance with and 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. The wireless communications circuitry may include one or more antennas. 
     The antennas can include loop antennas, inverted-F antennas, strip antennas, planar inverted-F antennas, slot antennas, hybrid antennas that include antenna structures of more than one type, or other suitable antennas. Conductive structures for the antennas may, if desired, be formed from conductive electronic device structures. The conductive electronic device structures may include conductive housing structures. The conductive housing structures may include a conductive peripheral housing member that runs around the periphery of an electronic device. The conductive peripheral housing member may serve as a bezel for a planar structure such as a display, may serve as sidewall structures for a device housing, or may form other housing structures. Gaps in the peripheral conductive member may be associated with the antennas. 
     An illustrative electronic device of the type that may be provided with one or more antennas is shown in  FIG. 1 . 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 cellular telephone, a media player, other handheld devices, etc. 
     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. 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, for example, be a touch screen that incorporates capacitive touch sensor electrodes. Display  14  may include image pixels formed form light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electronic ink elements, liquid crystal display (LCD) components, or other suitable image pixel structures. A cover glass layer may cover the surface of display  14 . Buttons such as button  16  may pass through openings in the cover glass. Opening  18  in the cover glass may be used to form a speaker port. 
     Housing  12  may include structures such as conductive peripheral housing member  20 . Member  20  may run around the substantially rectangular periphery of device  10  and display  14  and may surround rectangular device housing  12 . Member  20  or part of member  20  may serve as a bezel for display  14  (e.g., a cosmetic trim that surrounds all four sides of display  14  and/or helps hold display  14  to device  10 ). Member  20  may also, if desired, form sidewall structures for device  10 . 
     Member  20  may be formed of a conductive material such as metal. Member  20  may, for example, 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 member  20 . In a typical configuration, member  20  may have a thickness in vertical dimension Z of about 3 mm to 2 cm (as an example). Lateral dimensions X and Y of device  10  may be (in an example of the type shown in  FIG. 1 ) about 3 to 8 cm and about 5 to 20 cm, respectively (as examples). Other lateral and vertical dimensions may be used if desired (e.g., less than 3 mm, more than 3 mm, more than 2 cm, more than 20 cm, etc.). 
     It is not necessary for member  20  to have a uniform cross-section. For example, the top (highest Z) portion of member  20  may, if desired, have an inwardly protruding lip that helps hold display  14  in place. If desired, the bottom portion of member  20  may also have an enlarged lip (e.g., in the plane of the rear surface of device  10 ). In the example of  FIG. 1 , member  20  has substantially straight vertical sidewalls. This is merely illustrative. The sidewalls of member  20  may be curved or may have any other suitable shape. 
     In some configurations, grooves or other recessed portions may be formed in member  20  (e.g., in the exterior of member  20 ). These grooves or other recessed portions may be filled with materials such as dielectrics. Dielectric coatings that cover substantially all of the exterior surface of member  20  may also be used. By incorporating one or more dielectric structures over some or all of the exterior portions of member  20 , the immunity of the wireless performance of device  10  to contact by an external object such as a user&#39;s fingers may be enhanced and/or device aesthetics may be enhanced. 
     Openings may be formed in one or more portions of conductive peripheral housing member  20 . For example, openings  22  may be formed to accommodate buttons, opening  24  may be formed to accommodate an input-output port, and openings  26  may be used in forming speaker and microphone ports. Openings may also be formed for other components (e.g., buttons, audio jacks, other connectors, status indicators, other user interface components, etc.). 
     Display  14  may include conductive structures such as an array of capacitive touch sensor electrodes, conductive lines for addressing pixel elements, driver circuits, etc. Housing  12  also include internal structures such as metal frame members, a planar housing member (sometimes referred to as a midplate) that spans the walls of housing  12  (i.e., a substantially rectangular member that is welded or otherwise connected between opposing sides of the interior of member  20 ), printed circuit boards, and other internal conductive structures. These conductive structures may be located in the center of housing  12  (as an example). 
     In regions  28  and  30 , openings may be formed between portions of conductive peripheral member  20  and the internal conductive housing structures and conductive electrical components that make up device  10 . These openings may be filled with air, plastic, or other dielectrics. Conductive housing structures and other conductive structures in central portion  32  of device  10  may serve as a ground plane for the antennas in device  10 . The openings in regions  28  and  30  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, or may otherwise serve as part of antenna structures formed in regions  28  and  30 . 
     Portions of member  20  may be provided with gap structures. For example, member  20  may be provided with one or more gaps such as gap  34 , as shown in  FIG. 1 . The gaps may be filled with dielectric such as polymer, ceramic, glass, air, etc. Gaps such as gap  34  may divide member  16  into one or more segments. There may be, for example, two segments of member  20  (e.g., in an arrangement with two gaps), three segments of member  20  (e.g., in an arrangement with three gaps), four segments of member  20  (e.g., in an arrangement with four gaps, etc.). The segments of peripheral conductive member  16  that are formed in this way may form parts of antennas in device  10 . 
     In a typical scenario, device  10  may have upper and lower antennas (as an example). An upper antenna may, for example, be formed at the upper end of device  10  in region  28 . A lower antenna may, for example, be formed at the lower end of device  10  in region  30 . The antennas may be used separately to cover separate communications bands of interest or may be used together to implement an antenna diversity scheme or a multiple-input-multiple-output (MIMO) antenna scheme. 
     Antennas in device  10  may be used to support any communications bands of interest. For example, device  10  may include antenna structures for supporting local area network communications, voice and data cellular telephone communications, global positioning system (GPS) communications or other satellite navigation system communications, Bluetooth® communications, etc. 
     A top view of device  10  showing interior portions of housing  12  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may have internal conductive structures such as conductive housing structures  36 . Structures  36  may include, for example, planar metal structures (e.g., a conductive plate such as a midplate). Structures  36  may be mounted between opposing edges of conductive peripheral housing member  20  (e.g., the left and right edges of member  20  in the orientation of  FIG. 2 ). Structures  36  may include housing members, brackets and other support structures, circuits on printed circuit boards and other substrates, electrical components such as connectors and switches, and other conductive structures. These structures may form a ground plane for one or more antennas in device  10 . 
     For example, structures  36  may form a ground plane for an antenna in region  30  and a ground plane for an antenna in region  28  (as an example). In region  30 , an antenna may be formed that includes portions of conductive housing structures  36  and the portions of conductive peripheral housing member  20  that surround dielectric region (opening)  46 . In region  28 , an antenna may be formed that includes the portions of conductive housing structures  36  and the portions of conductive peripheral housing member  20  that surround opening  48 . 
     The antennas in regions  28  and  30  may be fed using any suitable antenna feed arrangement. As shown in  FIG. 2 , for example, an antenna in region  30  may be fed using positive antenna feed terminal  44  and ground antenna feed terminal  42 . An antenna in region  28  may be fed using positive antenna feed terminal  52  and ground antenna feed terminal  50 . Transmission line  40  may be coupled between the antenna feed for the antenna in region  30  and radio-frequency transceiver circuitry  38 . Transmission line  54  may be coupled between radio-frequency transceiver circuitry and the antenna in region  28 . Transmission lines  40  and  54  may include coaxial cables, microstrip transmission lines, stripline transmission lines, edge coupled microstrip transmission lines, edge coupled stripline transmission lines, and other transmission line structures. If desired, matching networks, switches, filters, conductive structures that serve as matching networks, and other circuits may be used in coupling transmission lines  40  and  54  to antenna structures in device  10 . The example of  FIG. 2  is merely illustrative. 
     Radio-frequency transceiver circuitry  38  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, and other circuitry for handling RF wireless signals. Circuitry  38  may include satellite navigation system receiver circuitry such as Global Positioning System (GPS) receiver circuitry (e.g., for receiving satellite positioning signals at 1575 MHz). Transceiver circuitry  38  may also include wireless local area network circuits for handling 2.4 GHz and 5 GHz bands for WiFi® (IEEE 802.11) communications and the 2.4 GHz Bluetooth® communications band. Circuitry  38  may include cellular telephone transceiver circuitry for handling wireless communications in cellular telephone bands such as bands at 850 MHz, 900 MHz, 1800 MHz, 1900 MHz, and 2100 MHz or other cellular telephone bands of interest. 
     During operation of the transceiver circuitry  38  in conveying antenna signals through antennas in regions  28  and  30 , the presence or absence of a user&#39;s fingers or other external objects in the vicinity of the antennas can affect the efficiency with which antenna signals are transmitted and received. In antennas that contains gaps in conductive peripheral housing member  20  (i.e., in an antenna of region  30  that contains gap  34  and in an antenna of region  28  that contains gap  34 ′), antenna performance can be affected more when conductive peripheral housing member  20  is contacted by a user&#39;s fingers or other external objects in the vicinity of the gaps than when other portions of conductive peripheral housing member  20  are contacted. By including dielectric material on some or all of the exterior portions of conductive peripheral housing member  20 , particularly in the vicinity of antenna gaps such as gaps  34 ′ and  34  of  FIG. 2 , antenna performance can be desensitized to contact between external objects and conductive peripheral housing member  20  in the vicinity of gaps  34 ′ and  34 . 
       FIG. 3  shows how the inclusion of dielectric  58  on exterior surface  60  of conductive peripheral housing member  20  may reduce the sensitivity of an antenna gap to contact with an external object. As shown in  FIG. 3 , there may be a capacitance Cg that is associated with gap  34  in conductive peripheral housing member  20 . Capacitance Cg is interposed within the conductive path between portion  20 - 1  and  20 - 2  of conductive peripheral housing member  20  and affects the degree to which transmission line  40  is impedance matched to the antenna. 
     When a user&#39;s finger such as finger  56  of  FIG. 3  contacts the antenna, capacitances Cp may be produced between member  20  and finger  56 . In the absence of dielectric layer  58 , the values of capacitances Cp may be large. Large values of Cp may alter the total effective capacitance between segments  20 - 1  and  20 - 2  (i.e., this capacitance may be increase above the nominal value of Cg in the absence of finger  56 ). Large value of Cp may therefore detune the antenna sufficiently to have an adverse effect on impedance matching and antenna performance. 
     When dielectric  58  is present, finger  56  may contact surface  62  of dielectric  58  rather than surface  60  of conductive peripheral housing member  20 . Because of the resulting separation D (e.g., a D value of 0.01 to 1 mm, 0.5 to 3 mm, more than 0.4 mm, more than 2 mm, less than 2 mm, etc.) between finger  56  and surface  60  of conductive peripheral housing member  20 , the values of capacitances Cp may be reduced. When Cp is small, the nominal value of the capacitance between segments  20 - 1  and  20 - 2  will tend to be unaffected and the antenna in which gap  34  is located will operate satisfactorily. 
     Dielectric  58  may be formed from epoxy, plastic, polymers such as polycarbonate (PC), acrylonitrile butadiene styrene (ABS), PC/ABS blends, polybutylene terephthalate (PDT), PC/PBT blends, other polymers, materials that include microspheres, voids, or other elements that reduce the dielectric constant of the materials, glass, ceramic (e.g., colored or clear ceramic that is incorporated into housing  12  using a ceramic injection molding process), paint, or fiber-based composites such as fiberglass, glass-filled nylon (e.g., glass fiber filled nylon) and other strengthened polymers, colored or clear plastic (polymers), other suitable dielectric materials or combinations of two or more of these materials. 
     The size, shape, and location of dielectric  58  may be selected to enhance antenna performance (e.g., to help ensure that antenna performance is immune to the effects of contact between a user&#39;s fingers and conductive peripheral housing member  20 ) while maintaining structural integrity and desired levels of aesthetics for device  10 . Dielectric  58  may be provided in the form of one or more layers of coating material, may be used to cover substantially all of the exterior surface of conductive peripheral housing member  20 , may be formed within a groove or one or more other recesses in conductive peripheral housing member  20 , or may be otherwise incorporated into housing  12  in the vicinity of gaps such as gaps  34  and  34 ′ of  FIG. 2 . 
     A cross-sectional view taken along the length of a conventional conductive peripheral housing member is shown in  FIG. 4 . In the arrangement of  FIG. 4 , finger  56  is in close contact with conductive peripheral contact member  20 ′ (which is connected to conventional midplate member  36 ′). Member  20 ′ is formed from solid metal and does not have any coatings. As a result, conventional conductive peripheral housing members such as member  20 ′ of  FIG. 4  may give rise to relatively large coupling capacitances Cp with finger  56 . 
       FIG. 5  is a cross-sectional view of a conductive peripheral housing member such as member  20  of  FIG. 1  that has been provided with dielectric  58  within a groove. In the example of  FIG. 5 , the groove has been formed by recess  68  in conductive peripheral housing member  20 . The recess forms a channel with a rectangular cross-section of thickness TH and width WD. Sidewalls  66  may enclose the sides of the channel (i.e., the top and bottom surfaces of dielectric  58  in the orientation of  FIG. 5 ). Optional chamfers  64  may be provided along the edges of sidewalls  66 . Groove  68  may run along all of conductive peripheral housing member  20  and may surround the rectangular housing of device  10 . 
       FIG. 6  is a perspective view of a portion of a conductive peripheral housing member such as member  20  of  FIG. 5  in the vicinity of gap  34 . As shown in  FIG. 6 , member  20  may be provided with inwardly protruding portions such as portions  20 ′ to enlarge the area over which segments  20 - 1  and  20 - 2  of member  20  are connected and thereby enhance the strength of the dielectric connection between segments  20 - 1  and  20 - 2 . Protruding portions  20 ′ may form a relatively large gap such as gap  70  (i.e., a gap that is wider than gap  34  and that therefore has a capacitance significantly less than capacitance Cg of  FIG. 3 ) and may have associated engagement features such as holes  72  that are filled with dielectric  58 . Gap  34  may be, for example, about 0.1 to 1 mm wide and gap  70  may be about 0.5 to 4 mm wide (as examples). 
     Dielectric coating  58  may be formed by filling recesses such as recess  68  with a liquid dielectric and curing the dielectric (e.g., using thermal curing or ultraviolet light curing). If desired, a substantially solid dielectric member  58  may be attached to member  20  by heating member  58  in a chamber. As shown in  FIG. 7 , chamber  74  may be used to heat cavity  76 . Dielectric member  58  may be molded, machined, or otherwise formed into a rectangular ring shape that surrounds the rectangular ring shape of conductive peripheral housing member  20  (e.g., before ring-shaped rectangular member  20  is connected to other structures in housing  12 ). 
     Dielectric member  58  may be formed from a polymer that shrinks when heated such as heat activated epoxy or other suitable plastic that shrinks upon application of elevated temperatures. Once heated in cavity  76 , dielectric structure  58  may shrink to fill recess  68 . The force imposed by the shrunken version of structure  58  may help ensure that structure  58  remains firmly attached to member  20  during use by a user. Structure  58  may be mounted within a groove or other recess in the outer surface of conductive peripheral housing member  20  or may be shrunken to coat substantially all of the surface of member  20  (e.g., the flat surface of a conductive peripheral housing member that does not have a recess). 
     The illustrative heated cavity arrangement of  FIG. 7  in which a polymer ring is shrunken into recess  68  by heating is merely illustrative. In general, dielectric  58  may be formed within recess  68  using any suitable fabrication process (e.g., injection molding of one shot, two shots, or more than two shots of polymer, fiber-composites, ceramic, or other materials, dipping, spraying, painting, machining, shrinking, or otherwise forming dielectric  58 ). 
     If desired, conductive peripheral housing member  20  may be provided with retention features that help hold dielectric  58  in place. An example is shown in the cross-sectional view of conductive peripheral housing member  20  of  FIG. 8 . As shown in  FIG. 8 , sidewall portions  66  of conductive peripheral housing member  20  may have surfaces  78  that are slanted so that they angle inwardly towards each other. This creates overhanging portions of member  20  that trap and retain dielectric  58  within recess  68 . 
     Another illustrative arrangement is shown in  FIG. 9 . With the configuration of  FIG. 9 , sidewall portions  66  of member  20  have straight sidewalls  78  that are perpendicular to the plane of exterior dielectric surface  62  of dielectric  58 . Member  20  of  FIG. 9  may, however, have a buried retention feature formed by portions  66 ′ and associated slanted wall surfaces  82 . 
     As shown in  FIG. 10 , dielectric  58  may extend continuously along longitudinal dimension  84  of conductive peripheral housing member  20  (i.e., along the dimension that runs parallel to the elongated length of conductive peripheral housing member  20  around the periphery of device  10 ). Groove  68  may, for example, extend continuously around the entire periphery of device  10  in a way that accommodates switches, connector openings, and other features in housing  12 . Dielectric  58  may fill the entire groove. Dielectric  58  may, for example, be formed by shrinking a hoop of plastic material of the type shown in  FIG. 7  so as to fill groove  68  on all four sides of device  10 . 
     In the example of  FIG. 11 , recess  68  is formed within a portion of conductive peripheral housing member  20  that is in the vicinity of gap  34  (i.e., a portion of member  20  that overlaps gap  34 ). In this type of arrangement, dielectric  58  does not extend around the entire periphery of device  10 , but rather is confined to discrete patches at particular locations on member  20 . In the  FIG. 11  configuration, the patch of dielectric material  58  that has been formed within recess  68  of conductive peripheral housing member  20  has a rectangular shape with length L (measured along longitudinal axis  84  of conductive peripheral housing member  20 ) and has width W. 
       FIG. 12  shows how recess  68  and the dielectric that fills recess  68  may have an oval patch shape that overlaps gap  34  within the exterior of conductive peripheral housing member  20 . 
     In  FIG. 13 , dielectric  58  has been placed within a diamond-shaped recess in the exterior of conductive peripheral housing member  20 . 
       FIG. 14  shows an illustrative configuration for dielectric  58  and recess  68  in which the edges of the recess have a curved shape. In general, the shape of recess  68  in the exterior of conductive peripheral housing member  12  may have curved sides, straight sides, sides with combinations of curved and straight segments, or other suitable configurations. 
     The shape of recess  68  (whether a diamond, rectangle, oval, or other shape) may be configured to overlap gap  34  so that gap  34  bisects the shape (i.e., so that half of the recess lies on one side of gap  34  and so that half of the recess lies on the other side of gap  34  when viewed from the exterior of device  10 ). Other (asymmetrical) arrangements may be used if desired. Arrangements in which the recess in conductive peripheral housing member and the dielectric that fills the recess are bisected by gap  34  are merely illustrative. 
     The curved-sided dielectric patch of  FIG. 14 , the diamond shaped patch of  FIG. 13  and the oval and rectangular patches of  FIGS. 12 and 11 , respectively, help to reduce capacitive coupling between a user&#39;s finger and conductive peripheral housing member  20  in a portion of member  20  that overlaps gap  34 . 
       FIG. 15  is a cross-sectional view of conductive peripheral housing member  20  viewed along its longitudinal dimension  84 . As shown in  FIG. 15 , dielectric  58  may cover substantially all of outer surface  60  of conductive peripheral housing member. Housing structures  88  and  90  (e.g., glass plates such as a cover glass plate for display  14  and a rear glass plate or other suitable housing structures) may, if desired, cover the seam between dielectric  58  and conductive peripheral housing member  20 . Retention features such as retention features  86  may be formed as described in connection with  FIGS. 8 and 9 . Retention features such as retention feature  86  may extend along member  20  around the entire periphery of device  10  or may be placed at discrete locations around the edge of device  10 . 
     As shown in  FIG. 16 , dielectric  58  may be formed from one or more separate dielectric structures. In the  FIG. 16  example, dielectric  58  includes inner dielectric layer  58 - 2  and outer dielectric layer  58 - 1 . Layers  58 - 2  and  58 - 1  may be formed using injection molding (e.g., first and second shots of plastic or injection molded ceramic), may be formed by shrinking plastic using a heated cavity of the type described in connection with  FIG. 7 , may be formed by forming a liquid coating layer (e.g., a layer of colored or clear epoxy, a layer of colored ink, etc.), or may be formed using other coating arrangements. With one suitable approach, inner dielectric structures  58 - 2  may contain polymer, ceramic, or other material with a solid (opaque) color or a pattern and outer dielectric structures  58 - 1  may include clear layer of polymer, ceramic, or other transparent dielectric material. 
     As shown in  FIG. 17 , inner dielectric structures  58 - 2  and outer dielectric structures  58 - 1  may be formed within recess  68  in conductive peripheral housing member  20  so that structures  58 - 1  and  58 - 2  are both located between opposing sidewall structures in member  20 . 
       FIG. 18  shows how inner dielectric structures  58 - 2  may be formed within recess  68  in conductive peripheral housing member  20  whereas outer dielectric structures  58 - 2  may form a coating layer that covers the exposed edge portions  90  of walls  66  of conductive peripheral housing member  20  and surface  92  of inner dielectric structures  58 - 2 . 
     In configurations that include multiple types of dielectric (e.g., one or more layers such as layers  58 - 1  and  58 - 2 ), it may be desirable to tailor the properties of the dielectric layers to their location within housing  12 . For example, an internal dielectric structure such as structure  58 - 2  of  FIG. 19  may be formed from a glass-filled polymer such as glass-filled nylon (e.g., nylon with glass fibers or other strengthening structures) that exhibits good structural strength, whereas an exterior dielectric structure such as structure  58 - 1  of  FIG. 19 , which may penetrate and fill gap  34  as well as filling recess  68 , may be formed from a material that has properties such as chemical resistance, stain resistance, an ability to take a smooth finish, and low losses at radio frequencies. An example of a satisfactory exterior dielectric material is PC/PBT, which may be less likely to stain then nylon. The inclusion of filler materials such as glass fibers in dielectric portion  58 - 2  of  FIG. 19  may help strengthen the joint being formed in member  20  in the vicinity of gap  34 , whereas the avoidance of glass fibers within the dielectric of gap  34  (i.e., ensuring that dielectric  58 - 1  is free of glass and other such strengthening structures) may help reduce antenna losses. If desired, ceramic and other materials may be used for structure  58 - 1  and/or structure  58 - 2  of  FIG. 19 . 
     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: 20101220
Publication Date: 20150203
Grant Date: 20150203
Priority Date: 20101220
Inventors: GOLKO ALBERT J.
JARVIS DANIEL W.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1698", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0407", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1698", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/241", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q13/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04W88/02", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1698", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/28", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0407", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q21/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q9/0407", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/2266", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 46235073