PATENT DOCUMENT

Publication Number: US-9093745-B2
Application Number: US-201213468289-A
Country: US
Kind Code: B2

Title: Antenna and proximity sensor structures having printed circuit and dielectric carrier layers

Abstract:
An electronic device may have a conductive housing with an antenna window. A display cover layer may be mounted on the front face of the device. Antenna and proximity sensor structures may include a dielectric support structure with a notch. The antenna window may have a protruding portion that extends into the notch between the display cover layer and the antenna and proximity sensor structures. The antenna and proximity sensor structures may have an antenna feed that is coupled to a first conductive layer by a high pass circuit and capacitive proximity sensor circuitry that is coupled to the first conductive layer and a parallel second conductive layer by a low pass circuit. The first conductive layer may be formed from a metal coating on the support structure. The second conductive layer may be formed from patterned metal traces in a flexible printed circuit.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a display cover layer; 
 antenna and proximity sensor structures that include parallel first and second conductive layers on a dielectric support structure, wherein the dielectric support structure has a surface and a notch; 
 an antenna window structure that has a portion that extends into the notch between the display cover layer and the antenna and proximity sensor structures, wherein the first conductive layer comprises metal on the surface of the dielectric support structure; and 
 a flexible printed circuit substrate, wherein the second conductive layer comprises metal on the flexible printed circuit substrate. 
 
     
     
       2. The electronic device defined in  claim 1  further comprising a capacitive proximity sensor circuit that is coupled to the first and second conductive layers. 
     
     
       3. The electronic device defined in  claim 2  further comprising:
 a high-pass circuit; and 
 an antenna feed that is coupled to the antenna and proximity sensor structures by the high-pass circuit. 
 
     
     
       4. The electronic device defined in  claim 3  wherein the display cover layer comprises a planar glass member, the electronic device further comprising a layer of opaque material interposed between a portion of the planar glass member and the antenna and proximity sensor structures. 
     
     
       5. The electronic device defined in  claim 3  wherein the high-pass circuit comprises first and second capacitors, wherein the antenna feed has a first antenna feed terminal that is coupled to the first conductive layer by the first capacitor, and wherein the antenna feed has a second antenna feed terminal that is coupled to the first conductive layer by the second capacitor. 
     
     
       6. The electronic device defined in  claim 1  further comprising:
 a capacitive proximity sensor circuit that is coupled to the first and second conductive layers by a low pass circuit; 
 an antenna feed having a first terminal that is coupled to the first conductive layer and having a second terminal that is coupled to the first conductive layer; and 
 a conductive housing in which the antenna window structure is mounted. 
 
     
     
       7. An electronic device, comprising:
 antenna and proximity sensor structures that include parallel first and second conductive layers on a dielectric support structure, wherein the dielectric support structure has a notch, at least some of the first conductive layer overlaps the notch, the antenna and proximity sensor structures include an antenna feed configured to receive antenna signals, the dielectric support structure has a surface, and the first conductive layer comprises metal on the surface; 
 capacitive proximity sensor circuitry coupled to the antenna and proximity sensor structures; 
 a flexible printed circuit substrate, wherein the second conductive layer comprises metal on the flexible printed circuit substrate; and 
 an antenna window structure having a portion that extends into the notch. 
 
     
     
       8. The electronic device defined in  claim 7  further comprising a high pass circuit coupled between the antenna feed and the first conductive layer. 
     
     
       9. The electronic device defined in  claim 8  further comprising a low pass circuit coupled between the capacitive proximity sensor circuitry and the first and second conductive layers. 
     
     
       10. The electronic device defined in  claim 7  further comprising:
 a metal housing in which the antenna window structure is mounted. 
 
     
     
       11. The electronic device defined in  claim 7  wherein the dielectric support structure is configured to be hollow. 
     
     
       12. The electronic device defined in  claim 10  further comprising a camera, wherein the dielectric support structure has a recessed portion that is configured to accommodate the camera.

Description:
BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to antennas in electronic devices. 
     Electronic devices such as portable computers and handheld electronic devices are becoming increasingly popular. Devices such as these are often provided with wireless communications capabilities. For example, electronic devices may use long-range wireless communications circuitry to communicate using cellular telephone bands. Electronic devices may use short-range wireless communications links to handle communications with nearby equipment. Electronic devices are also often provided with sensors and other electronic components. 
     It can be difficult to incorporate antennas, sensors, and other electrical components successfully into an electronic device. Some electronic devices are manufactured with small form factors, so space for components is limited. In many electronic devices, the presence of conductive structures can influence the performance of electronic components, further restricting potential mounting arrangements for components such as wireless communications devices and sensors. 
     It would therefore be desirable to be able to provide improved ways in which to incorporate components in electronic devices. 
     SUMMARY 
     An electronic device may have a housing in which antenna and proximity sensor structures may be mounted. The housing may be a conductive housing with an antenna window. The antenna and proximity sensor structures may be mounted behind the antenna window. During operation, antenna signals and electromagnetic proximity sensor signals may pass through the antenna window. 
     A display cover layer such as a planar glass member may be mounted on the front face of the device. The antenna and proximity sensor structures may include a dielectric support structure with recessed features such as a notch. The antenna window may have a protruding portion that extends into the notch between the display cover layer and the antenna and proximity sensor structures. The display cover layer may be mounted over the protruding portion. A layer of opaque material on the underside of the display cover layer over the protruding portion may hide the antenna and proximity sensor structures and other internal device structures from view from the exterior of the device. 
     The antenna and proximity sensor structures may include parallel first and second conductive layers on the dielectric support structure. The antenna and proximity sensor structures may have an antenna feed that is coupled to the first conductive layer by a high pass circuit. The feed may have first and second terminals. The first terminal may be coupled to the first conductive layer by a first capacitor and the second terminal may be coupled to the first conductive layer by a second capacitor. 
     Capacitive proximity sensor circuitry in the electronic device may be coupled to the first and second conductive layers by a low pass circuit. The capacitive proximity sensor circuitry may, for example, be coupled to the first conductive layer by a first inductor and the second conductive layer by a second inductor. 
     The first conductive layer may be formed from a metal coating on the support structure. The second conductive layer may be formed from patterned metal traces in a printed circuit. 
     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 front perspective view of an illustrative electronic device of the type that may be provided with component structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a rear perspective view of an illustrative electronic device such as the electronic device of  FIG. 1  in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional side view of a portion of the electronic device of  FIGS. 1 and 2  in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative dielectric carrier for an integrated antenna and proximity sensor in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an electronic component formed from conductive traces on a dielectric carrier and conductive traces on a flexible printed circuit that is attached to the dielectric carrier in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an illustrative carrier for antenna and proximity sensor structures in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional view of an illustrative hollow dielectric carrier formed from two parts that have been soldered together by soldering together metal traces on the parts in accordance with an embodiment of the present invention. 
         FIG. 8  is a side view of an illustrative dielectric carrier showing how the carrier may have a recess to accommodate components mounted on a substrate such as a flexible printed circuit in accordance with an embodiment of the present invention. 
         FIG. 9  is a side view of an illustrative dielectric carrier showing how the carrier may have a recess for accommodating electronic components such as a camera when mounting the carrier within an electronic device housing in accordance with an embodiment of the present invention. 
         FIG. 10  is a diagram showing how an integrated antenna and proximity sensor structure may be formed from parallel layers of conductive material and may be coupled to an antenna feed and proximity sensor circuitry in accordance with an embodiment of the present invention. 
         FIG. 11  shows illustrative patterns that may be used for conductive layers in an integrated antenna and proximity sensor structure of the type shown in  FIG. 10  in accordance with an embodiment of the present invention. 
         FIG. 12  is a flow chart of illustrative steps in forming integrated antenna and proximity sensor structures in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with antennas, sensors, and other electronic components. It may be desirable to form some of these components from flexible structures. For example, it may be desirable to form components for electronic devices using flexible printed circuit structures. Flexible printed circuits, which are sometimes referred to as flex circuits, may include patterned metal traces on flexible substrates such as layers of polyimide or other flexible polymer sheets. Flex circuits may be used in forming antennas, capacitive sensors, assemblies that include antenna and capacitive sensor structures, other electronic device components, or combinations of these structures. 
     In some situations, it may be desirable to form conductive electronic component structures that have bends and other potentially complex shapes. For example, antennas, sensors, and other electronic components may include one or more bends to facilitate mounting within an electronic device housing. To ensure that electronic components such as antenna and sensor structures can be mounted within this type of device housing, electronic components such as antenna and sensor structures may be formed using patterned metal layers on flexible printed circuits and patterned metal coatings formed on dielectric carrier structures such as molded plastic structures. 
     An illustrative electronic device in which electronic components may be used is shown in  FIG. 1 . Device  10  may include one or more antenna resonating elements, one or more capacitive proximity sensor structures, one or more components that include antenna structures and proximity sensor structures, and other electronic components. Illustrative arrangements in which an electronic device such as device  10  of  FIG. 1  is provided with electronic components such as antenna structures and/or proximity sensor structures that are formed from multiple conductive layers are sometimes described herein as an example. In general, electronic devices may be provided with any suitable electronic components that include multiple conductive layers. The electronic devices may be, for example, desktop computers, computers integrated into computer monitors, portable computers, tablet computers, handheld devices, cellular telephones, wristwatch devices, pendant devices, other small or miniature devices, televisions, set-top boxes, or other electronic equipment. 
     As shown in  FIG. 1 , device  10  may have a display such as display  50 . Display  50  may be mounted on a front (top) surface of device  10  or may be mounted elsewhere in device  10 . Device  10  may have a housing such as housing  12 . Housing  12  may have curved portions that form the edges of device  10  and a relatively planar portion that forms the rear surface of device  10  (as an example). Housing  12  may also have other shapes, if desired. 
     Housing  12  may be formed from conductive materials such as metal (e.g., aluminum, stainless steel, etc.), carbon-fiber composite material or other fiber-based composites, glass, ceramic, plastic, or other materials. A radio-frequency (RF) window (sometimes referred to as an antenna window) such as RF window  58  may be formed in housing  12  (e.g., in a configuration in which the rest of housing  12  is formed from conductive structures). Window  58  may be formed from plastic, glass, ceramic, or other dielectric material. Antenna and proximity sensor structures for device  10  may be formed in the vicinity of window  58  or may be covered with dielectric portions of housing  12 . 
     Device  10  may have user input-output devices such as button  59 . Display  50  may be a touch screen display that is used in gathering user touch input. The surface of display  50  may be covered using a dielectric member such as a planar cover glass member or a clear layer of plastic. The central portion of display  50  (shown as region  56  in  FIG. 1 ) may be an active region that displays images and that is sensitive to touch input. The peripheral portion of display  50  such as region  54  may be an inactive region that is free from touch sensor electrodes and that does not display images. 
     A layer of material such as opaque ink or plastic may be placed on the underside of display  50  in peripheral region  54  (e.g., on the underside of the cover glass). This layer may be transparent to radio-frequency signals. The conductive touch sensor electrodes in region  56  may tend to block radio-frequency signals. However, radio-frequency signals may pass through the cover glass and the opaque layer in inactive display region  54  (as an example). Radio-frequency signals may also pass through antenna window  58  or dielectric housing walls in housing formed from dielectric material. Lower-frequency electromagnetic fields may also pass through window  58  or other dielectric housing structures, so capacitance measurements for a proximity sensor may be made through antenna window  58  or other dielectric housing structures. 
     With one suitable arrangement, housing  12  may be formed from a metal such as aluminum. Portions of housing  12  in the vicinity of antenna window  58  may be used as antenna ground. Antenna window  58  may be formed from a dielectric material such as polycarbonate (PC), acrylonitrile butadiene styrene (ABS), a PC/ABS blend, or other plastics (as examples). Window  58  may be attached to housing  12  using adhesive, fasteners, or other suitable attachment mechanisms. To ensure that device  10  has an attractive appearance, it may be desirable to form window  58  so that the exterior surfaces of window  58  conform to the edge profile exhibited by housing  12  in other portions of device  10 . For example, if housing  12  has straight edges  12 A and a flat bottom surface, window  58  may be formed with a right-angle bend and vertical sidewalls. If housing  12  has curved edges  12 A, window  58  may have a similarly curved exterior surface along the edge of device  10 . 
       FIG. 2  is a rear perspective view of device  10  of  FIG. 1  showing how device  10  may have a relatively planar rear surface  12 B and showing how antenna window  58  may be rectangular in shape with curved portions that match the shape of curved housing edges  12 A. 
     A cross-sectional view of device  10  taken along line  1300  of  FIG. 2  and viewed in direction  1302  is shown in  FIG. 3 . As shown in  FIG. 3 , antenna and proximity sensor structures  200  may be mounted within device  10  in the vicinity of RF window (antenna window)  58 . Structures  200  may include conductive material that serves as an antenna resonating element for an antenna. The antenna may be fed using transmission line  44 . Transmission line  44  may have a positive signal conductor that is coupled to positive antenna feed terminal  76  and a ground signal conductor that is coupled to antenna ground (e.g., housing  12  and other conductive structures) at ground antenna feed terminal  78 . 
     The antenna resonating element formed from structures  200  may be based on any suitable antenna resonating element design (e.g., structures  200  may form a patch antenna resonating element, a single arm inverted-F antenna structure, a dual-arm inverted-F antenna structure, other suitable multi-arm or single arm inverted-F antenna structures, a closed and/or open slot antenna structure, a loop antenna structure, a monopole, a dipole, a planar inverted-F antenna structure, a hybrid of any two or more of these designs, etc.). Housing  12  may serve as antenna ground for an antenna formed from structure  200  and/or other conductive structures within device  10  may serve as ground (e.g., conductive components, traces on printed circuits, etc.). 
     The conductive material in structures  200  may also form one or more proximity sensor capacitor electrodes. With one suitable arrangement, structures  200  may include conductive layers  202  on dielectric carrier  204 . Layers  202  may include parallel patterned conductive layers such as one or more flexible printed circuit metal layers and/or one or more patterned metal layers on the surface of carrier  204 . As an example, layers  202  may include at least first and second parallel layers of patterned conductive material. 
     In configurations for layers  202  that include first and second parallel layers, the first layer may be formed on the surface of dielectric carrier  204 . For example, the first conductive layer may be formed from a patterned metal coating that is formed directly on the surface of a plastic carrier. The second conductive layer may be formed as part of a substrate such as a flexible printed circuit (as an example). A layer of adhesive may be used in mounting the flexible printed circuit to dielectric carrier  204  on top of the first conductive layer formed from the patterned metal coating on the surface of dielectric carrier  204 . In this configuration, portions of the flexible printed circuit and the layer of adhesive may be interposed between the parallel first and second conductive layers. 
     An antenna feed may have terminals that are coupled to one of the parallel conductive layers. At frequencies associated with antenna signals, the first and second layers may be effectively shorted to each other and may form an antenna resonating element. Proximity sensor circuitry such as capacitive proximity sensor circuitry may have terminals coupled respectively to the first and second layers. At frequencies that are below the antenna signal frequencies, the first and second layers may serve as first and second proximity sensor capacitor electrodes (e.g., an inwardly directed electrode and an outwardly directed electrode). 
     Structures  200  may be formed by using laser direct structuring (LDS) techniques to form patterned metal traces on dielectric carrier  204  and by laminating a patterned flex circuit layer to the outer surface of carrier  204  using adhesive. With laser direct structuring techniques, a metal complex or other materials may be incorporated into the plastic material that forms carrier  204  to ensure that carrier  204  can be activated by light exposure. Upon exposure to laser light in particular areas, the surface of carrier  204  becomes sensitized for subsequent metal growth. During metal growth operations following selective surface activation with laser light, metal will grow only in the activated areas exposed to the laser light. 
     By using laser direct structuring to pattern metal onto the surface of carrier  204 , carrier  204  may incorporate potentially complex shapes. As an example, carrier  204  may include recessed features such as notch (bend)  206  to accommodate bent portion  58 ′ of antenna window  58 . As shown in  FIG. 3 , bent portion  58 ′ of antenna window  58  may protrude inwardly from the exterior surface of antenna window  58  and may form a ledge that is interposed between a portion of display cover layer  60  and the notched portion of structures  200 . Portions of the first layer (e.g., the laser direct structuring traces) and/or portions of the second layer (e.g., the flexible printed circuit) may be mounted on carrier  204  over some or all of notch  206 , as illustrated by layer  202  on notch  206  in  FIG. 3 . 
     If desired, components may be mounted on the flex circuit in conductive layers  202  of structures  200 . These components may include, for example, filter circuitry, impedance matching circuitry, resistors, capacitors, inductors, switches, and other electronic components. Conductive layers  202  may also include conductive traces for forming antenna resonating element patterns, transmission lines, and proximity sensor electrode patterns (as examples). 
     The first and second conductive layers may form electrodes for a proximity sensor that are also used as an antenna resonating element. The electrodes in layers  202  may be electrically isolated from each other. 
     If desired, conductive connections may, in certain locations, be formed between a signal conductor on one layers in layers  202  and an electrode on another layer in layers  202 . Solder or other conductive materials (e.g., anisotropic conductive film, etc.) may be used in forming this type of connection. For example, a via that is filled with solder may be used to route signals from a signal path on one layer to a portion of a patterned electrode on another layer. 
     The electrode formed from the first layer of patterned conductive structures  202  may face outwards (e.g., in direction  300  for the portion located under window  58 ) and the electrode formed from the second patterned conductive layer may face inwards into housing  12  in direction  302  (as an example). Electromagnetic fields associated with conductive layers  202  may also pass through inactive portion  54  of display cover layer  60 . 
     The two layers of patterned conductive material (electrodes) in layers  202  may be electrically isolated from each other by interposed dielectric to form a parallel plate capacitor. At frequencies below about 1 MHz, the parallel plate capacitor may have a relatively high impedance (e.g., forming a DC open circuit), so that the patterned layers may serve as independent first and second proximity sensor capacitor electrodes. At frequencies above 1 MHz (e.g., at frequencies above 100 MHz or above 1 GHz), the impedance of the parallel plate capacitor is low, so the patterned conductive layers may be effectively shorted together. This allows both of the layers to operate together as a unitary patterned conductor in an antenna resonating element. 
     During operation of the antenna formed from structures  200 , radio-frequency antenna signals can be conveyed through dielectric window  58 . Radio-frequency antenna signals associated with structures  200  may also be conveyed through a display cover member such as cover layer  60 . Display cover layer  60  may be formed from one or more clear layers of glass, plastic, or other materials. 
     Display  50  may have an active region such as region  56  in which cover layer  60  has underlying conductive structure such as display panel module  64 . The structures in display panel  64  such as touch sensor electrodes and active display pixel circuitry may be conductive and may therefore attenuate radio-frequency signals. In region  54 , however, display  50  may be inactive (i.e., panel  64  may be absent). An opaque layer such as plastic or ink  62  may be formed on the underside of transparent cover glass  60  in region  54  to block the antenna resonating element from view by a user of device  10 . Opaque material  62  and the dielectric material of cover layer  60  in region  54  may be sufficiently transparent to radio-frequency signals that radio-frequency signals can be conveyed through these structures in directions  70 . 
     Device  10  may include one or more internal electrical components such as components  23 . Components  23  may include storage and processing circuitry such as microprocessors, digital signal processors, application specific integrated circuits, memory chips, and other control circuitry. Components  23  may be mounted on one or more substrates such as substrate  79  (e.g., rigid printed circuit boards such as boards formed from fiberglass-filled epoxy, flexible printed circuits, molded plastic substrates, etc.). Components  23  may include input-output circuitry such as sensor circuitry (e.g., capacitive proximity sensor circuitry), wireless circuitry such as radio-frequency transceiver circuitry (e.g., circuitry for cellular telephone communications, wireless local area network communications, satellite navigation system communications, near field communications, and other wireless communications), amplifier circuitry, and other circuits. Connectors such as connector  81  may be used in interconnecting circuitry  23  to communications paths (e.g., transmission line  44  of  FIG. 3 ). 
     A perspective view of structures  200  in an illustrative configuration in which structures  200  have been provided with a notch such as notch  206  is shown in  FIG. 4 . As shown in  FIG. 4 , structures  200  may have an upper planar surface such as surface  200 F and a curved outer surface such as surface  200 E. Structures  200  may also have an interior surface such as surface  200 I. To accommodate housing structures such as antenna window protrusion  58 ′ of  FIG. 3 , structures  200  may have a recessed feature such as notch  206  or other structures that exhibit a bend. As shown in  FIG. 3 , structures  200  may have an elongated shape that runs parallel to longitudinal axis  208 . Notch  206  may run along the outer edge of structures  200  parallel to axis  208  and parallel to the edge of housing  12  and antenna window protrusion  58 ′. The configuration for structures  200  in which notch  206  runs parallel to the length of structures  200  is merely illustrative. Other shapes and sizes may be used for structures  200  if desired. 
     As shown in the cross-sectional side view of  FIG. 5 , conductive layers  202  may be formed on the exterior surface of structures  200 . Conductive layers  202  may include a lower conductive layer such as layer  210  and an upper conductive layer such as layer  216 . Layer  210  may be formed from a patterned metal coating (metal traces) formed directly on the exterior surface of dielectric support structure  204 . Layer  216  may, as an example, be formed from a layer of patterned metal (metal traces) formed within a substrate such as substrate  214 . Substrate  214  may be, for example, a sheet of polyimide or other polymer layer that forms a substrate for a printed circuit (i.e., flexible printed circuit  212 ). Substrate  214  may be attached to the surface of layer  210  using adhesive  268 . 
     Metal layer  210  may be deposited using physical vapor deposition and subsequent patterning (e.g., etching or machining), may be deposited using a molded interconnect device (MID) technique in which multiple shots of plastic are formed in a mold and subsequently coated with metal that is selectively attracted to one of the shots of plastic, or may be deposited using laser direct structuring (LDS) techniques. Laser direct structuring approaches involve applying light to the surface of support  204  in a desired pattern to selectively activate a particular area on support  204  for subsequent metal deposition (e.g., electroplating). Support  204  may, if desired, be formed from a plastic that includes a metal complex to promote light activation. 
     Conductive layer  216  in flexible printed circuit  212  may be patterned using photolithography, screen printing, pad printing, or other suitable patterning techniques. Flexible printed circuit  212  may be attached to the surface of support structure  204  using adhesive  268  or other attachment mechanisms. Use of a flexible printed circuit to carry layer  216  allows layer  216  to conform to non-planar surface features such as notch  206 , if desired. In configurations in which recessed features such a notch  206  contain shape bends, it may sometimes be desirable to cover the recessed features only with patterned coating layer  210  (which can form a conformal coating layer on the recessed features) and not with flexible printed circuit  214 . 
     Dielectric structure  204  may serve as a support structure for layers  202  in structures  200 . Structure  204  may be formed from glass, ceramic, plastic, or other dielectric material. To reduce dielectric losses during antenna operation, structure  204  may include lower-dielectric constant structures such as embedded structures  218  of  FIG. 6 . Structures  218  may have a dielectric constant that is lower than that of the main material used in forming structure  204 . For example, structures  218  may be formed from hollow beads, may be formed from foam beads, may be formed from solid beads of material that have a dielectric constant lower than that of the primary material in structure  204 , or may be formed from voids (e.g., gas-filled bubbles) or other structures that help lower the effective dielectric constant of structure  204 . 
     If desired, structure  204  may be hollow to reduce the effective dielectric constant of structure  204 . This type of configuration is shown in  FIG. 7 . As shown in the illustrative configuration of  FIG. 7 , structure  204  may be formed from mating portions (e.g., mating half cavities) such as upper portion  204 U and lower portion  204 L. Solder  220  may be used to join portions  204 U and  204 L (e.g., by connecting opposing portions of conductive layer  210  along the edges of portions  204 U and  204 L). 
     As shown in  FIG. 8 , structure  204  may, if desired, include a surface portion such as recessed portion  222 . Recessed portion  222  may be a depression in the surface of structure  204  such as a notch, recess, groove, hole, or other feature that is configured to accommodate protruding components such as components  226  on substrate  224 . Components  226  may be, for example, components associated with an antenna or proximity sensor circuit such as impedance matching circuitry, filter circuitry, etc. Substrate  224  may be a flexible printed circuit substrate, a rigid printed circuit substrate, or other suitable dielectric substrate. For example, substrate  224  may be formed using flexible printed circuit  212  of  FIG. 5  and components  226  may be coupled to conductive layer  216  of printed circuit  212 . 
     As shown in  FIG. 9 , structure  204  may have a recess or other feature such as recess  228  of  FIG. 9  to accommodate internal electronic components such as camera  230  or other devices in housing  12  of device  10 . 
       FIG. 10  is a side view of a portion of structures  200  showing how conductive layers  202  in structures  200  may be coupled to antenna circuitry and proximity sensor circuitry. As shown in  FIG. 10 , structures  200  may terminals such as positive antenna feed terminal  76  and ground antenna feed terminal  78  that form an antenna feed for structures  200  such as antenna feed  228 . Antenna feed  228  may be coupled to positive and ground conductors in transmission line  44  ( FIG. 3 ). Transmission line  44  may, in turn, be coupled to radio-frequency transceiver circuitry (see, e.g., components  23  of  FIG. 3 ) to support wireless communications. Terminal  78  may be coupled to ground  230 . Circuitry such as capacitors  232  and  234  may be used to couple feed  228  to structures  202 . Capacitor  232  may be coupled between ground  230  (feed terminal  78 ) and layer  210 . Capacitor  234  may be coupled between feed terminal  76  and layer  210 . 
     At high frequencies (i.e., a signal frequencies associated with antenna operation such as frequencies above 100 MHz), capacitors  232  and  234  may form short circuits that couple feed  228  to layer  210  in layers  202 . A distributed capacitance may be formed between layers  210  and  216  (which serve as respective electrode plates in a parallel-plate capacitor). At antenna signal frequencies, layers  210  and  216  may be effectively shorted together and therefore may both participate in forming an antenna for device  10 . At lower frequencies (i.e., frequencies associated with gathering capacitive proximity sensor signals), capacitors  232  and  234  may help prevent proximity sensor signals and other signals that could potentially interfere with the wireless transceiver circuitry of device  10  from reaching feed  228 . 
     Proximity sensor circuitry  236  may include a capacitance-to-digital converter and other circuitry for gathering proximity sensor signals from structures  202 . Proximity sensor circuitry  236  may have a pair of terminals coupled to low pass circuitry such as inductors  238  and  240 . Layer  216  may be coupled to circuitry  236  via inductor  238 . Layer  210  may be coupled to circuitry  236  via inductor  240 . Inductors  238  and  240  may be configured to pass signals associated with operating a capacitive proximity sensor (circuitry  236 ) while blocking radio-frequency antenna signals that could interfere with proximity sensor circuitry  236 . 
     The capacitance values for capacitors  232  and  234  are preferably of sufficient size to ensure that the impedance of these capacitors is low and does not disrupt antenna operation at frequencies associated with wireless signals in device  10 . For example, if path  44  ( FIG. 3 ) is being used to handle signals at frequencies of 100 MHz or more (e.g., cellular telephone signals, wireless local area network signals, etc.), the capacitance values of capacitors  232  and  234  may be 10 pF or more, 100 pF or more (e.g., 100 s of pF), or may have other suitable sizes that ensure that transmitted and received antenna signals are not blocked. At lower frequencies, the impedance of capacitors  232  and  234  is preferably sufficiently large to prevent interference from reaching the antenna resonating element formed from structures  200 . 
     Proximity sensor circuitry  236  may be coupled to layers  202  in structures  200  through inductors  238  and  240 . For example, proximity sensor circuitry such as capacitance-to-digital converter circuitry or other control circuitry may be used to make capacitance measurements using one or more capacitor electrodes formed from patterned conductive layers  210  and  216  of structures  200 . Layer  216  may form a capacitive proximity sensor electrode. Layer  210  may form a shield layer for the proximity sensor. Inductors  238  and  240  may have impedance values (e.g., impedances of 100 s of nH) that prevent radio-frequency antenna signals (e.g., antenna signals at frequencies of 100 MHz or more) from reaching capacitance-to-digital converter or other circuitry in proximity sensor circuitry  236  while allowing AC proximity sensor signals (e.g., signals with frequencies below 1 MHz) to pass between structures  200  and proximity sensor circuitry  236 . 
     Capacitors  232  and  234  form a high pass filter. By using high-pass circuitry, low frequency noise can be prevented from interfering with antenna operation for structures  200 . Inductors  238  and  240  form a low-pass filter. By using low-pass circuitry, radio-frequency noise from antenna signals can be prevented from interfering with proximity sensor operation for structures  200 . If desired, other types of high-pass and low-pass filters may be interposed between structures  200  and the radio-frequency transceiver circuitry and proximity sensor circuitry that is associated with structures  200 . The arrangement of  FIG. 10  is merely illustrative. 
       FIG. 11  is a top view of illustrative conductive structures  202  in an unassembled (unfolded) state. In practice, the layers of  FIG. 11  are formed around support structure  204 . Patterned conductor layouts other than the layout of  FIG. 11  may be used in structures  200  if desired. The example of  FIG. 11  is merely illustrative. 
     In the example of  FIG. 11 , conductive layer  210 , which is denoted by cross-hatching, lies on the bottom of layers  202  (i.e., layers  202  are being viewed from the exterior of structure  200 ). Flexible printed circuit  212  includes substrate  214  and conductive traces  216 . Substrate  214  may have a shape given by dash-and-dotted outline  214  in  FIG. 11 . Metal traces  216  may have the shape given by dotted line  216  in  FIG. 11 . Flexible printed circuit  214  may have a proximity sensor tail such as tail  242  and an antenna feed tail such as tail  244 . 
     Proximity sensor tail  242  may have a first signal path such as path  246  that is coupled to layer  216  and may have a second signal path such as signal path  248  that is coupled to layer  210  using via connection  250 . 
     Antenna feed tail  244  may have a microstrip transmission line formed from conductive line  254  and underlying portions of ground path structure  252  (e.g., an underlying metal layer on flexible printed circuit  212 ). Terminal  76  may be coupled to layer  210  using path  254  and via  258 . Terminal  78  may be coupled to layer  210  using path portion  252 ′ of structures  252  and via  256 . Vias such as vias  256 ,  258 , and  250  may include solder bumps or other structures for forming electrical connections with layer  210 . 
     A flow chart of illustrative steps involved in forming structures such as structures  200  in device  10  is shown in  FIG. 12 . 
     At step  260 , carrier structures such as structure  204  may be formed. For example, structure  204  may be formed using plastic injection molding, machining, and other fabrication techniques. If desired, structure  204  may be formed from a dielectric such as glass or ceramic. Structure  204  may include recesses and other bent features that help accommodate device structures such as antenna window structure  58 , housing structure  12 , cover layer  60 , and other structures in device  10 . Structure  204  may, for example, have an elongated shape characterized by a longitudinal axis such as axis  208  of  FIG. 4  and may have a recessed portion such as notch  206  that runs parallel to longitudinal axis  208  and the edge of structure  204 . 
     At step  262 , patterned conductive layer  210  may be formed. As an example, a laser direct structuring tool may be used to apply laser light to the external surface of structure  204  to activate a desired surface area for subsequent metal deposition. Following activation, structure  204  may be exposed to metal deposition material (e.g., an electroplating bath or other metal source) to grow patterned metal layer  210 . 
     At step  264 , one or more patterned conductive layers such as patterned metal layer  216  may be formed on flexible printed circuit  212  (e.g., using photolithography, screen printing, or other printed circuit patterning techniques). 
     At step  266 , structures  200  may be assembled and mounted in device  10 . For example, flexible printed circuit  212  may, if desired, be attached to the surface of layer  210  using adhesive (see, e.g., adhesive layer  268  in  FIG. 5 ). Solder, conductive adhesive, or other suitable materials may be used in coupling the traces of flexible printed circuit  212  to layer  210  and/or other conductive structures (e.g., transmission line structure  44 , proximity sensor circuitry  236 , components such as components  226  of  FIG. 8  and components  23  of  FIG. 3 , etc.). Structures  200  may then be mounted in housing  12  of device  10  under antenna window  58  and portion  54  of display cover layer  60 , as shown in  FIG. 3 . 
     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: 20120510
Publication Date: 20150728
Grant Date: 20150728
Priority Date: 20120510
Inventors: YARGA SALIH
SHAH NIRALI
LI QINGXIANG
SCHLUB ROBERT W.
Assignee: APPLE INC
CPC Classifications: [{"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/245", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/245", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/245", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/44", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01R29/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 48430946