PATENT DOCUMENT

Publication Number: US-9582085-B2
Application Number: US-201414502949-A
Country: US
Kind Code: B2

Title: Electronic devices with molded insulator and via structures

Abstract:
An electronic device may have printed circuits to which electrical components are mounted. Plastic may be molded over a printed circuit. Vias may be formed in the printed circuit that connect metal traces on the surface of the molded plastic to metal traces on the printed circuit. The vias may be formed by drilling or by covering the metal traces on the printed circuit with mold pins in a molding tool during plastic molding operations. Plated metal traces or other metal traces may extend onto the interior surface of via holes. Vias may also be filled with conductive material such as solder or conductive adhesive. Metal members that are soldered or otherwise connected to printed circuit traces may be used in coupling surface metal traces to printed circuit traces. Antenna structure, shielding structures, and electrodes for a stylus may be formed using the metal traces on the molded plastic.

Claims:
What is claimed is: 
     
       1. Apparatus, comprising:
 an elongated printed circuit extending along a longitudinal axis; 
 a contact pad formed from metal traces on the printed circuit; 
 molded plastic on the printed circuit, wherein the molded plastic has an outer surface and an elongated cylindrical shape surrounding at least part of the elongated printed circuit and extending along the longitudinal axis, wherein the elongated cylindrical shape has a perimeter wrapping around the longitudinal axis; 
 a metal trace on the outer surface that transmits data signals from the printed circuit and forms a ring-shaped electrode wrapping around the perimeter; and 
 a via through the plastic electrically coupling the metal trace to the contact pad. 
 
     
     
       2. The apparatus defined in  claim 1  wherein the outer surface has an activated region and wherein the metal trace on the outer surface comprises a plated metal trace on the activated region. 
     
     
       3. The apparatus defined in  claim 2  wherein the activated region comprises a laser-activated region that is activated by exposure to laser light. 
     
     
       4. The apparatus defined in  claim 1  wherein the via has an inner surface and wherein a metal trace is formed on the inner surface. 
     
     
       5. The apparatus defined in  claim 4  further comprising a conductive material formed in the via on the metal trace that is on the inner surface. 
     
     
       6. The apparatus defined in  claim 5  wherein the conductive material comprises solder. 
     
     
       7. The apparatus defined in  claim 6  wherein the ring-shaped electrode comprises one of a plurality of ring-shaped electrodes on the outer surface at different respective positions along the longitudinal axis. 
     
     
       8. The apparatus defined in  claim 6  wherein the metal trace on the outer surface is configured to form an antenna structure, the apparatus further comprising:
 radio-frequency transceiver circuitry on the printed circuit that is electrically coupled to the antenna structure. 
 
     
     
       9. The apparatus defined in  claim 1  further comprising a hollow tube structure, wherein at least a portion of the molded plastic and the printed circuit board are located in the hollow tube structure. 
     
     
       10. The apparatus defined in  claim 1  wherein the molded plastic comprises injection molded plastic formed using an injection molding tool with mold pins, wherein the via is formed from a hole in the injection molded plastic that is formed by the mold pins, and wherein the printed circuit is at least partly embedded within the molded plastic. 
     
     
       11. A method, comprising:
 forming a printed circuit having a surface with a metal pad; 
 pressing against the metal pad with a mold pin in an injection molding tool to protect a portion of the metal pad; 
 molding plastic over the printed circuit with the injection molding tool while the mold pin protects the portion of the metal pad and prevents the molded plastic from covering the protected portion of the metal pad; 
 removing the mold pin to create a via hole; and 
 forming metal traces on an outer surface of the molded plastic and along an inner surface of the via hole to electrically connect the metal traces on the outer surface to the metal pad. 
 
     
     
       12. The method defined in  claim 11  wherein forming the metal traces comprises plating the metal traces onto the outer surface. 
     
     
       13. The method defined in  claim 12  wherein the metal pad is a first of a pair of first and second aligned metal pads on opposing sides of the printed circuit, wherein the mold pin is a first of a pair of first and second mold pins, and wherein molding the plastic comprises molding the plastic while the first mold pin presses against the first metal pad and the second mold pin presses against the second metal pad in an opposing direction. 
     
     
       14. The method defined in  claim 11  wherein at least part of the printed circuit is located in a tube and wherein molding the plastic comprises molding the plastic into the tube around the printed circuit. 
     
     
       15. The method defined in  claim 11  wherein injection molding the plastic comprises forming a cylindrical plastic structure and wherein forming the metal traces on the outer surface of the molded plastic comprises forming a plurality of ring-shaped metal electrodes. 
     
     
       16. A stylus that provides input to touch sensors, comprising:
 an elongated printed circuit extending along a longitudinal axis and having metal traces; 
 molded plastic covering the printed circuit, wherein the molded plastic has an outer surface and an elongated shape extending along the longitudinal axis; 
 additional metal traces on the outer surface of the molded plastic; and 
 a conductive structure interposed between the additional metal traces on the outer surface and the printed circuit coupling the additional metal traces on the outer surface to the metal traces of the printed circuit, wherein the additional metal traces on the outer surface overlap the printed circuit, and wherein the additional metal traces on the outer surface comprise circumferential electrodes that encircle the longitudinal axis and provide electromagnetic signals to the touch sensors. 
 
     
     
       17. The stylus defined in  claim 16  wherein the conductive structure comprises:
 a metal member mounted on the metal traces of the printed circuit, wherein the metal member is located under a via hole in the molded plastic; and 
 a metal coating extending from the additional metal traces on the outer surface along surfaces of the via hole to couple the additional metal traces on the outer surface to the metal member. 
 
     
     
       18. The stylus defined in  claim 17  wherein the conductive structure further comprises conductive material in the via hole, wherein the conductive material in the via hole is a conductive material selected from the group consisting of: solder, metallic paint, and conductive adhesive. 
     
     
       19. The stylus defined in  claim 16  wherein the conductive structure comprises a metal member mounted on the metal traces of the printed circuit, wherein the metal member has a portion extending through the outer surface and contacting the additional metal traces on the outer surface. 
     
     
       20. The stylus defined in  claim 16  wherein the conductive structure comprises a conductive via extending through the molded plastic from the outer surface to the metal traces on the printed circuit.

Description:
BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to interconnecting printed circuits and metal traces to form conductive structures for electronic devices. 
     Electronic devices include electronic components such as integrated circuits, sensors, and other circuitry. Electronic components may be mounted on printed circuit boards. Printed circuits may also be used to form signal cables. In some scenarios, it may be desirable to form conductive structures using metal traces on printed circuits. For example, electrodes, shields, antennas, and other metal structures may be formed using metal traces. Vias may be used to interconnect traces on different printed circuit board layers. 
     If care is not taken, the conductive structures will not be well integrated with other device structures, electrical connections will not be reliable, and the shapes and locations of metal traces relative to other conductive structures will be poorly defined. 
     It would therefore be desirable to be able to provide improved techniques for forming conductive structures for electronic devices. 
     SUMMARY 
     An electronic device may have printed circuits to which electrical components are mounted. Plastic may be molded over a printed circuit. Vias may be formed in the printed circuit to connect metal traces on the surface of the molded plastic to metal traces on the printed circuit. The metal traces on the surface of the molded plastic may be used in forming antenna structures, shielding structures, electrodes for an active computer stylus, or other conductive structures. 
     The vias may be formed by drilling or by covering the metal traces on the printed circuit with mold pins in a molding tool during plastic molding operations. Plated metal traces or other metal traces may extend along the interior surfaces of via holes. Vias may also be filled with conductive material such as solder or conductive adhesive. Metal members that are soldered or otherwise connected to printed circuit traces may be used in coupling surface metal traces to printed circuit traces. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device and associated electronic equipment in accordance with an embodiment. 
         FIG. 2  is a diagram of equipment that may be used in forming an electronic device in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative stylus interacting with external equipment such as a touch pad or tablet computer in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of an illustrative printed circuit in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of an illustrative printed circuit covered with molded plastic in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of an illustrative through via structure in accordance with an embodiment. 
         FIG. 7  is cross-sectional side view of an illustrative via structure that terminates on a printed circuit board pad in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view of an illustrative via structure that terminates on a metal structure such as a standoff that has been soldered to a printed circuit board pad in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of an illustrative metal structure that forms an electrical connection through molded plastic in accordance with an embodiment. 
         FIG. 10  is a cross-sectional side view of a printed circuit with pads that are being contacted and deformed by mold pins in accordance with an embodiment. 
         FIG. 11  is a cross-sectional side view of a printed circuit with metal pads in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of a printed circuit of the type shown in  FIG. 11  being compressed between a pair of mold pins in accordance with an embodiment. 
         FIG. 13  is a cross-sectional side view of the printed circuit of  FIG. 12  following injection molding of a layer of plastic over the printed circuit and removal of the mold pins in accordance with an embodiment. 
         FIG. 14  is a cross-sectional side view of the printed circuit of  FIG. 13  following formation of conductive via structures in accordance with an embodiment. 
         FIG. 15  is a cross-sectional side view of an illustrative electronic device that includes conductive structures of the type shown in  FIG. 14  in accordance with an embodiment. 
         FIG. 16  is a cross-sectional side view of an illustrative electromagnetic shielding structure formed using via structures in accordance with an embodiment. 
         FIG. 17  is a schematic diagram of illustrative wireless circuitry in an electronic device in accordance with an embodiment. 
         FIG. 18  is a cross-sectional side view of illustrative antenna structures that include a via structure in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may include conductive structures that are supported by printed circuits and dielectric structures such as molded plastic structures. The conductive structures may form electrodes, signal paths for interconnecting electrical components, electromagnetic shielding structures, antenna structures, or other conductive device structures. 
     An illustrative electronic device of the type that may include conductive structures such as these is shown in  FIG. 1 . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, stylus that is used in supplying drawing or writing input to a touch pad or a touch screen display, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     Electronic device may interact with external equipment  20 . Equipment  20  may be a device such as device  10 , a tablet computer or other device with a touch screen display, a touch pad, or other external electronic equipment. Signals may be conveyed wirelessly between device  10  and equipment  20  during operation, as shown by wireless signals  22 . Wireless signals  22  may include near-field wireless signals. For example, near-field electromagnetic coupling such as capacitive or inductive near-field coupling may allow signals in device  10  to be conveyed to equipment  20 . If, for example, device  10  is an active computer stylus and equipment  20  has a touch sensor (e.g., a touch sensor that forms part of a touch pad or a touch sensor that forms part of a touch screen display), device  10  may use electrodes in device  10  to convey signals to equipment  20  that equipment  20  captures and uses as writing input. Wireless signals  22  may also include radio-frequency signals that form part of a local wireless area network such as Bluetooth® signals, IEEE 802.11 (WiFi®) signals, or other wireless signals. 
     As shown in  FIG. 1 , electronic device  10  may have control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  16  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communications circuits, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  18  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  18  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors such as touch sensors, proximity sensors, ambient light sensors, compasses, gyroscopes, accelerometers, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  18  and may receive status information and other output from device  10  using the output resources of input-output devices  18 . 
     Input-output devices  18  may include one or more displays. Device  10  may, for example, include a touch screen display that includes a touch sensor for gathering touch input from a user or a display that is insensitive to touch. Stand-alone touch sensors for device  10  may also be provided (e.g., in configurations in which device  10  does not include a display or in which both a touch screen display and a stand-alone sensor are desired). A touch sensor for device  10  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. 
     Power for device  10  may be provided by an external source of power and/or an internal battery. The components for device  10  such as circuitry  16  and devices  18  and other structures in device  10  may be implemented using integrated circuits, discrete components (e.g., resistors, capacitors, and inductors), microelectromechanical systems (MEMS) devices, portions of housing structures, packaged parts, and other devices and structures. 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images for a user on one or more displays and may use other internal components such as input-output devices  18 . Device  10  may use communications circuits to send and receive wireless and wired data. For example, device  10  may use light-emitting components to transmit data and may use light-receiving components to receive transmitted light signals. Device  10  may also use light-emitting components, light-receiving components, audio components, capacitive sensors, microelectromechanical systems devices, and other components as sensors and output devices. Device  10  may use wireless circuits in circuitry  16  (e.g., a baseband processor and associated radio-frequency transceiver circuitry, near-field communications circuits, or other circuitry that emits and/or receives electromagnetic signals) to transmit and receive wireless signals. For example, device  10  may transmit and receive cellular telephone signals, wireless local area network signals, near-field electromagnetic signals, or other wireless data. 
       FIG. 2  is a diagram showing illustrative equipment of the type that may be used processing printed circuits and other structures to form electronic device  10 . As shown in  FIG. 2 , device  10  may be formed using one or more printed circuits such as printed circuit  24 . In an assembled device, circuitry can be mounted to printed circuit  24 . Printed circuit  24  may be a rigid printed circuit board (e.g., a printed circuit board formed from fiberglass-filled epoxy or other rigid printed circuit board material) or may be a flexible printed circuit (e.g., a printed circuit formed from a sheet of polyimide or other flexible polymer layer). Patterned metal traces within printed circuit  24  and additional conductive structures in device  10  may be used to form signals paths that interconnect integrated circuits and other components, electromagnetic shielding, antenna structures, electrodes for sensing or for emitting electromagnetic fields (e.g., near-field electromagnetic signals), and other device structures. 
     If desired, conductive structures such as these may be supported using substrates other than printed circuit  24 . For example, metal traces may be supported on dielectric materials such as glass, ceramic, sapphire or other crystalline dielectric materials, or plastic. Configurations in which device  10  contains conductive structures that are supported partly by one or more printed circuits and partly by other dielectric material such as plastic are sometimes described herein as an example. This is, however, merely illustrative. In general, conductive structures for device  10  may be supported using any suitable insulating support structures. 
     Plastic support structures for the conductive structures of device  10  may be shaped using cutting tools, machining tools, laser-based tools for drilling and cutting, water-jet cutting equipment, plasma cutting equipment, sanding and grinding equipment, and other equipment for forming plastic into desired shapes. With one suitable arrangement, which may sometimes be described herein as an example, one or more plastic support structures in device  10  are formed using plastic molding techniques (e.g., injection molding or other molding techniques). 
     Plastic may be molded onto or around some or all of printed circuit  24  using molding equipment such as molding tool  26  of  FIG. 2 . For example, one or more printed circuits such as printed circuit  24  may be inserted into a mold cavity. Molten plastic may then be injected into the cavity. As the plastic is injected into the cavity, the plastic comes into contact with printed circuit  24 . Depending on the shape of the mold cavity, the molded plastic may cover some or all of printed circuit  24 . Printed circuit  24  may, for example, be embedded completely within the molded plastic or may be partly embedded within the molded plastic. Plastic may also be molded onto one or more surfaces of printed circuit  24  (e.g., part of an upper surface, part of a rear surface and/or part of one or more edges of printed circuit  24 ). 
     The outermost surfaces of the molded plastic may serve to support metal traces. These metal traces may be interconnected with metal traces in the printed circuit using vias. Vias may be formed as part of the molding process (e.g., using mold pins in tool  26 ) or may be formed after the plastic has been molded onto printed circuit  24  using via formation equipment  28 . Via formation equipment  28  may including machining equipment such as mechanical drills or punches, may include laser-based equipment (e.g., laser drilling equipment), may include etching equipment (e.g., plasma etching equipment), or may include other tools for forming openings through plastic. Via structures may be used to interconnect metal structures that are located on the surface of the plastic that is molded to printed circuit  24  using molding tool  26  with underlying metal structures such as metal pads and other metal traces in printed circuit  24 . 
     After vias have been formed through the plastic (e.g., after mold pins have been used to create openings in the plastic during the molding operations with molding tool  26  and/or after laser-drilling or mechanical drilling equipment  28  has been used to form vias), deposition and patterning equipment  30  may be used to form conductive structures. Deposition and patterning equipment  30  may include equipment for depositing blanket metal films, equipment for depositing metal through shadow masks, equipment for locally depositing conductive materials (e.g., conductive paint deposition equipment such as screen printing equipment, pad printing equipment, and ink-jet printing equipment), soldering equipment, equipment for depositing solder paste (e.g., screen printing equipment, etc.) and reflowing the solder paste (e.g., an oven, laser, hot-bar or other heat source), equipment for etching deposited films, equipment for forming welds, equipment for applying conductive materials using spraying, needle dispenser equipment, electroplating equipment (e.g., equipment for selectively plating metal onto portions of a plastic structure that have been activated by localized exposure to laser light or that have been subjected to other activation processes such as mechanical activation processes), or other equipment for depositing and patterning conductive structures. The conductive structures may, as an example, include metal traces that run down the sides of vias in the molded plastic and may include solder or other conductive material that is used as a conductive filler in the vias (i.e., material that is placed within the vias on top of the metal traces in the vias). 
     Following formation of printed circuit structures with overmolded plastic and conductive structures that are interconnected using vias, assembly tools  32  may be used to complete the assembly of some or all of device  10 . Tools  32  may include manually controlled equipment and/or automated equipment that mounts the printed circuit and plastic structures in a housing for device  10  and that incorporates other electrical components into the housing for device  10  (e.g., control circuitry  16  and input-output devices  18  of  FIG. 1 ). Assembly tools  32  may be used in forming a completed electronic device  10  or part of an electronic device. The equipment of  FIG. 2  may be used to mount electrical components onto printed circuit  24  before and/or after molding plastic onto printed circuit  24  with tool  26 . Electrical components such as integrated circuits, sensors, switches, and other circuitry may, for example, be soldered onto printed circuit  24  before printed circuit  24  is inserted into molding tool  26  and/or after via formation have been performed using equipment such as equipment  26 ,  28 , and/or  30 . For example, components may be soldered onto printed circuit  24  using assembly tools  32  after vias have been formed using tools  26 ,  28 , and/or  30  by using soldering equipment in tools  32 . 
     As shown in  FIG. 3 , device  10  may be an electronic device such as a computer stylus (pen). Stylus  10  may be an active stylus that emits alternating current near-field electromagnetic signals from its tip that are detected by electrodes  38  on surface  36  of external equipment  20 . Equipment  20  may be, for example, a tablet computer or a touch pad. Electrodes  38  may be organized in an array or other pattern on surface  36  of equipment  20 . Electrodes  38  may be capacitive sensor electrodes that forms a touch sensor array (e.g., a capacitive touch sensor for a touch screen display in a tablet computer or a capacitive touch sensor array for a touch pad or other device without an overlapping display). The touch sensor formed from electrodes  38  may monitor the signals emitted by stylus  10  and may process this information to determine the location of the tip of stylus  10  in lateral dimensions X and Y. This allows stylus  10  to be used to draw lines and provide other stylus input during use of equipment  20 . 
     Stylus  36  may have a housing such as housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). Device  10  may have inner housing structures that provide additional structural support to device  10  and/or that serve as mounting platforms for printed circuits and other structures. Structural internal housing members may sometimes be referred to as housing structures and may be considered to form part of housing  12 . 
     Device  10  and housing  12  may have an elongated shape such as an elongated cylindrical shape or other elongated shape that facilitates handheld operation by a user. Device  10  and housing  12  may, for example, have an elongated shape that extends along longitudinal axis  40 . Printed circuit  24  may have an elongated shape that extends along axis  40  within housing  12 . Electrical components  34  may be mounted on printed circuit  24  (e.g., components such as integrated circuits, discrete components such as inductors, resistors, and capacitors, sensors, switches, connectors, and other circuitry). Plastic may be molded around printed circuit  24  and/or around some or all of components  34  using molding tool  26 , as described in connection with  FIG. 2 . 
     A cross-sectional side view of an illustrative printed circuit of the type that may be used in device  10  is shown in  FIG. 4 . As shown in  FIG. 4 , printed circuit  24  may have one or more dielectric layers  42  (e.g., layers of fiberglass-filled epoxy or other rigid printed circuit board material, layers of polyimide or other flexible sheets of polymer in a flexible printed circuit, etc.). One or more patterned layers of metal may form metal traces  44  and may be supported by dielectric layers  42 . Metal traces  44  may be formed from metals such as copper or other metals. Vias  46  may be formed using openings such as opening  50  and opening  52 . Metal traces in the interior of vias  46  such as metal  48  may be used in forming conductive via sidewalls. Conductive materials may also be placed in openings  50  and  52  (e.g., solder, conductive adhesive, etc.). 
     Vias  46  may include through vias (vias that pass through printed circuit  24 ) using through-holes such as opening  50 . Vias  46  may also include blind vias (vias that pass partway through circuit  24 ) using openings such as opening  52  that pass through some but not all of the layers  42  in printed circuit  24 . 
     If desired, vias may be formed in molded plastic structures in addition to or instead of passing through printed circuit  24 . Consider, as an example, the structures of  FIG. 5 . In the example of  FIG. 5 , plastic  54  has been molded over printed circuit  24 . Plastic  54  may, as an example, have a molded shape that allows plastic  54  to be accommodated within the tip of a stylus housing. For example, plastic  54  may have a cylindrical shape with a tapered tip (see, e.g., the left side of plastic  54  of  FIG. 5 ). Vias  58  may be formed in plastic  54 . Vias  58  may extend between metal traces  56  on outer surface  60  of plastic  54  and printed circuit  24 . Metal traces  56  may have ring shapes (circumferential shapes) that extend around the circumference of plastic  54  (i.e., traces  56  may form ring-shape circumferential electrodes that encircle longitudinal axis  40  of  FIG. 5 ). 
     If desired, vias  58  may have portions (see, e.g., through via  46  of  FIG. 4 ) that pass through printed circuit  24 . Vias  58  may also be configured to terminate at the upper and/or lower surfaces of printed circuit  24  (e.g., on metal traces that form contact pads on printed circuit  24 ). Metal traces  56  may be formed by selectively exposing portions of the surface of plastic  54  to laser light or applying other surface treatment to activate these portions. Metal plating operations may then be formed to produce metal traces. During plating operations, metal traces  56  will only be formed in the portions of plastic  54  that have been selectively activated. If desired, other types of conductive material may be used to form conductive structures  56  (e.g., conductive paint, solder, metal foil, etc.). The use of laser-based metal deposition processes is merely illustrative. 
     The interior surfaces of vias  58  may be coated with metal traces (see, e.g., metal traces  48  in vias  46  of  FIG. 4 ). The metal traces in vias  58  may be formed using laser activation and metal plating, may be formed using physical vapor deposition techniques, or may be formed using other techniques. Solder, conductive adhesive, or other conductive material may be deposited in the interior of vias  58  (e.g., on top of the metal traces in vias  58 ). The presence of the conductive material may help strengthen the vias and increase the conductivity of the vias. 
       FIG. 6  is a cross-sectional side view of an illustrative via formed through plastic  54 . As shown in  FIG. 6 , via  58  may have an inner surface coated with metal traces  56 W (e.g., plated metal traces or metal traces formed using other techniques). Metal traces  44  in printed circuit  24  may be shorted to metal trace  56 W. Metal traces such as metal traces  44 T and  44 B may have circular footprints (when viewed along the axis of via  58 ) and may surround via  58  to provide additional connections to metal traces  56 T. 
     Conductive material  62  may fill via  58 . The presence of conductive material  62  may help strengthen via  58  and may provide additional conductivity to via  58 . Conductive material  62  may be formed from solder, conductive adhesive, plated metal, wire, conductive paint, or other conductive material. Via  58  electrically connects surface traces  56  on outer surface  60  of plastic  54  to metal traces  44  in printed circuit  24 . 
     In the example of  FIG. 6 , via  58  passes through plastic  54  and through printed circuit  24 .  FIG. 7  is a cross-sectional side view of plastic  54  and printed circuit  24  in a scenario in which via  58  terminates on a contact pad on the surface of printed circuit  24 . As shown in  FIG. 7 , printed circuit  24  may have inner metal traces  44  that are coupled by vias  46  to surface trace  44 P. Surface metal trace  44 P lies on the upper surface of printed circuit  24  (in the example of  FIG. 7 ) and forms a metal pad. Metal pad  44 P may be covered by some of metal traces  56 W during plating operations or other metal coating operations (e.g., when coating the interior of via  58  with metal  56 W) or may be left uncovered by metal  56 W. Conductive material  62  fills via  58  and is electrically connected to contact pad  44 P. With this arrangement, printed circuit traces  44  are coupled to surface traces  56  on plastic  54  through the conductive structures of via  58 . 
     If desired, a metal structure such as metal structure  66  may be soldered to contact pad  44 P, as shown in  FIG. 8 . Metal structure  66  may be a copper member or other metal member (sometimes referred to as a standoff). Solder  64  or other conductive material may be used to couple structure  66  to pad  44 P. Metal coating  56 W on the inner surface of via  58  may cover the upper portion of metal structure  66  or metal structure  66  may be uncovered by coating  56 W. Solder  62  or other conductive material may fill via  58  to short metal trace  56  on the surface of plastic  54  to metal traces in printed circuit  24 . 
     In the illustrative configuration of  FIG. 9 , metal structure  66  has a portion such as portion  66 P that is sufficiently tall to penetrate through the upper surface  60  of plastic  54 . Metal structure  66  is mounted to printed circuit board  24  (e.g., by using conductive material  64  such as solder or conductive adhesive to attach metal member  66  to pad  44 P). During molding, surface  66 N of portion  66 P of metal structure  66  may be protected by a portion of the mold so that surface  66 N remains uncovered by plastic  54 . This allows metal trace  56  on surface  60  of plastic  54  to electrically contact metal structure  66  and thereby become electrically connected to metal trace  44 P on printed circuit  24 . With arrangements of the type shown in  FIG. 9 , no vias holes need be filled with metal traces and solder, because electrical connections are made through metal structure  66 . 
     Vias  58  may be formed using mold pins in molding tool  26 . An illustrative configuration is shown in  FIG. 10 . In the side view of  FIG. 10 , pads  44 P on printed circuit  24  are being compressed between opposing mold pins  70 . Mold pins  70  form part of molding tool  26  and are moved towards each other in directions  72  before plastic is injected into the mold cavity of tool  26 . As shown in  FIG. 10 , the tips of mold pins  70  may compress pads  44 P sufficiently to form slight indentations in pads  44 P, thereby helping to seal off pads  44 P from molten plastic. This ensures that plastic  54  will not cover these surface portions of pads  44 P during molding. During subsequent via formation operations, the absence of plastic over pads  44 P will ensure that metal traces and other conductive material (e.g., solder, conductive adhesive, etc.) will form satisfactory electrical contact to pads  44 P. 
     An illustrative approach for forming vias  58  using mold pins  70  is shown in  FIGS. 11, 12, 13, and 14 . 
     Initially, metal traces are formed on printed circuit  24 . The metal traces may include contact pads  44 P, as shown in  FIG. 11 . Two pads  44 P on opposing surfaces of printed circuit  24  are shown in the example of  FIG. 11 . In general, there may be any suitable number of pads  44 P (e.g., one or more, two or more, four or more, ten or more, fewer than 20, etc.). Pads  44 P may be formed on one side of printed circuit  24  or may be formed on opposing sides of printed circuit  24 . When aligned as shown in  FIG. 11 , the overlapping nature of pads  44 P allows mold pins to simultaneously press inwards in opposing directions without deflecting printed circuit  24 , as described in connection with  FIG. 10  (see, e.g.,  FIG. 12  in which mold pins  70  have been used to cover portions of pads  44 P on the upper and lower surfaces of printed circuit  24 ). 
     After covering the surfaces of pads  44 P using one or more mold pins in molding tool  26 , plastic  54  may be molded in the interior of molding tool  26  (e.g., in a mold cavity that surrounds printed circuit  24  and mold pins  70 ). Once the plastic has cooled and set, the mold die may be removed and pins  70  may be pulled away from plastic  54  to reveal openings such as holes  74  of  FIG. 13 . Openings  74  may terminate at the exposed surfaces of pads  44 P in printed circuit  24 . 
     Electrical connections may be formed for vias  58  by incorporating one or more conductive materials into openings  74 . As shown in  FIG. 14 , for example, metal traces  56  may have portions that extend along the interior surfaces of openings  74  and that cover pads  44 P (as in the example of  FIG. 14 ) or that leave pads  44 P bare. Metal traces  56  may be deposited using physical vapor deposition, plating (e.g., plating following selective laser activation of portions of the surface inside openings  74  and on outer surface  60  of plastic  54 ), or using other suitable deposition techniques. If desired, conductive material  62  may be deposited on top of metal traces  56  in opening  74  to fill via  58  (e.g., in situations in which traces  56  do not completely fill openings  74 ). 
       FIG. 15  is a cross-sectional side view of device  10  in an illustrative configuration in which device  10  serves as a stylus for providing pen input to a touch pad or touch screen display in a device with a display. As shown in  FIG. 15 , stylus  10  may have an elongated housing such as housing  12 . Housing  12  may have the shape of a cylinder, a cylindrical shape with one or more flattened sides, a tube with flat sides, or other suitable shape. Components  80  (e.g., a battery, wireless circuitry including one or more antennas and radio-frequency transceiver circuitry, control circuitry  16  and/or input-output devices  18 ) may be enclosed in housing  12 . Printed circuit board  24  may also be enclosed within housing  12 . As shown in  FIG. 15 , printed circuit board  24  may be at least partly embedded within molded plastic  54 . Support structure  78  may have the shape of a cylindrical tube or a hollow tube of other cross-sectional shape in region P 1  and may have the shape of a flat open platform in region P 2  (as examples). Components  34  may be mounted on printed circuit  24  in region P 2  and elsewhere along the length of printed circuit  24 . Plastic  54  may be molded over printed circuit  24  and in the interior of the tube portion of support structure  78 . In tip region  76 , circumferential metal traces (e.g., ring-shaped metal traces  56  that run around the circumference of plastic  54  as described in connection with  FIG. 5 ) may be used to form one or more stylus electrodes. The stylus electrodes may include, for example, a tip electrode, a ground electrode, and a ring electrode and may be used for generating near-field electromagnetic signals that are detected by the touch sensor array in external equipment  20 . Vias  58  may be used to electrically connect each ring-shaped electrode  56  to a respective metal trace  44  in printed circuit  24 . The metal traces of printed circuit  24  may couple each electrode to electrode control circuitry implemented using components  34  or other circuitry in device  10 . 
     If desired, electromagnetic shielding structures may be formed using metal traces  56 , vias  58 , and plastic  54 . As shown in  FIG. 16 , for example, components such as component  34  may mounted on printed circuit  34 . For example, components such as components  34  may have contacts that mate with corresponding contacts on printed circuit  24 . Solder  82  or other conductive material such as conductive adhesive may be used to couple each contact pad on component  34  to a corresponding contact formed from a metal trace on printed circuit  24 . Plastic  54  may be molded over components such as component  34 . Metal traces  56  on plastic  54  preferably include portions that overlap component  34  to provide electromagnetic shielding for component  34 . Multiple components  34  may be shielded in this way, if desired. Via holes for vias  58  may be formed using mold pins, using laser drilling, using mechanical drilling, using etching, or using other suitable hole formation techniques. Metal traces  56  may extend into the via openings to short metal traces  56  to pads  44 P on printed circuit  24 . Pads  44 P may be metal traces that form ground contacts or contacts that are maintained at other suitable voltage levels to allow metal traces  56  to serve as electromagnetic shielding for component  34 . Vias  58  may be filled with conductive material  62  (e.g., in scenarios in which metal traces  56  in vias  58  do not completely fill vias  58 ). If desired, vias  58  may surround the periphery of component  34  to laterally shield component  34 . 
     As shown in  FIG. 17 , device  10  may contain one or more antennas  86 . Antennas  86  may be inverted-F antennas, patch antennas, monopole antennas, dipole antennas, loop antennas, slot antennas, other types of antenna, or hybrid antennas based on one or more antenna structures such as these. There may be one antenna  86  in device  10  or may be two or more antennas in device  10 . Radio-frequency transceiver circuitry  84  may be coupled to antenna(s)  86  using transmission line paths and can receive and/or transmit wireless signals using antenna(s)  86 . For example, radio-frequency transceiver circuitry  84  may be used to transmit and/or receive cellular telephone signals, wireless local area network signals (e.g., IEEE 802.11 signals), Bluetooth® signals, etc. 
     As shown in  FIG. 18 , antenna structures such as structures associated with antenna  86  may be formed using molded plastic  54 , printed circuit  24 , metal traces  56 , and vias such as via  58 . Printed circuit  24  may include signal lines formed from metal traces  44 . These signal lines may, for example form transmission lines that couple circuitry such as transceiver  84  to antenna  86 . Antenna  86  may have a ground formed from metal traces  44  or other ground structures and a resonating element (or ground) formed from metal traces  56  on surface  60  of molded plastic  54 . Via  58  may be formed from openings in plastic  54  (e.g., openings formed using mold pins, drilling, etc.), traces  56  that coat the interior surfaces of the via openings, and optional conductive via filling material  62  (e.g., solder, conductive adhesive, etc.). 
     If desired, other conductive structures may be formed using traces  56 , vias  58 , traces  44 , and conductive components in device  10 . Printed circuit  24  may also be used to support more than one type of conductive structure. As an example, device  10  may have a printed circuit with overmolded plastic that supports stylus electrodes for an active computer stylus, an antenna, and shielding structures. The conductive structures may be used in a computer stylus or any other electronic equipment. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20140930
Publication Date: 20170228
Grant Date: 20170228
Priority Date: 20140930
Inventors: ZIMMERMAN AIDAN N.
BERG BRUCE E.
AUNE GLENN
ARMENDARIZ KEVIN C.
BROOKS RYAN P.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K3/4038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2224/16227", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/0014", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/0014", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09027", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/4038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/09545", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09027", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0274", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/09545", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0274", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01L2223/6677", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/115", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L2924/3025", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/115", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/4038", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/09027", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/115", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/0014", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K3/284", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/09545", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/0274", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0442", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0442", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 55584346