PATENT DOCUMENT

Publication Number: US-9766727-B2
Application Number: US-201514792516-A
Country: US
Kind Code: B2

Title: Computer stylus with antenna

Abstract:
A computer stylus may have an elongated body with a tip and an opposing end having components such as a connector and an antenna. Metal structures for the antenna may be supported using a molded plastic support with metal traces or may be formed using flexible printed circuits or other structures. Metal and plastic tubes may be used in forming the body of the stylus. A metal tube may have an opening in which an antenna is mounted. A plastic tube may serve as an outer housing for the stylus and may cover the metal tube and the opening in which the antenna is mounted. A transmission line such as a cable may be coupled to an antenna feed. The cable may pass through an opening in the metal tube and may be covered using a strip of conductive foam.

Claims:
What is claimed is: 
     
       1. A computer stylus, comprising:
 an elongated body having a tip and an opposing end coupled by a shaft that extends along a longitudinal axis and that has a circumference; 
 an antenna that wraps around at least part of the circumference; and 
 a connector at the opposing end that has a plurality of contact pads, wherein the antenna is located between the connector and the tip, the shaft includes a metal tube that extends from the tip to the antenna, and the shaft includes a plastic outer tube that covers the antenna and that extends from the tip to the opposing end. 
 
     
     
       2. The computer stylus defined in  claim 1  wherein the antenna comprises a flexible printed circuit wrapped around a plastic tube. 
     
     
       3. The computer stylus defined in  claim 1  wherein the antenna comprises a metal antenna resonating element trace on a plastic support structure. 
     
     
       4. The computer stylus defined in  claim 3  further comprising a metal tube that forms at least part of the shaft. 
     
     
       5. The computer stylus defined in  claim 4  wherein the antenna has a metal trace that is shorted to the metal tube by conductive adhesive. 
     
     
       6. The computer stylus defined in  claim 5  further comprising a coaxial cable, wherein the metal tube has an opening through which the coaxial cable passes. 
     
     
       7. The computer stylus defined in  claim 6  wherein the antenna has a feed and wherein the coaxial cable is coupled to the feed. 
     
     
       8. The computer stylus defined in  claim 7  further comprising a strip of conductive foam that covers at least part of the coaxial cable. 
     
     
       9. The computer stylus defined in  claim 1  wherein the antenna comprises a ring antenna having a metal antenna resonating element that wraps entirely around the circumference. 
     
     
       10. A computer stylus, comprising:
 an elongated body having a tip and an opposing end coupled by a shaft that extends along a longitudinal axis; and 
 an antenna at the opposing end that is formed from metal traces on a dome-shaped plastic support. 
 
     
     
       11. The computer stylus defined in  claim 10  wherein the antenna includes a magnet. 
     
     
       12. The computer stylus defined in  claim 11  wherein the antenna comprises an inverted-F antenna. 
     
     
       13. The computer stylus defined in  claim 12  wherein the antenna comprises an antenna ground trace and an antenna resonating element trace coupled by a return path trace. 
     
     
       14. The computer stylus defined in  claim 13  wherein the antenna resonating element trace is electrically coupled to the magnet and antenna currents pass through the magnet. 
     
     
       15. The computer stylus defined in  claim 14  further comprising:
 an antenna feed coupled to the antenna resonating element trace and the antenna ground trace; and 
 a metal tube that forms at least part of the shaft, wherein the metal tube is shorted to the antenna ground trace. 
 
     
     
       16. The computer stylus defined in  claim 15  further comprising a screw that is shorted to the antenna ground trace and a coaxial cable that is coupled to the antenna feed. 
     
     
       17. The computer stylus defined in  claim 10 , wherein the antenna comprises an antenna ground trace and an antenna resonating element trace coupled by a return path trace. 
     
     
       18. A computer stylus, comprising:
 an elongated body having a tip and an opposing end coupled by a shaft that extends along a longitudinal axis and that has a circumference; 
 a connector at the opposing end that has a plurality of connector contact pads; 
 electrical components in the shaft that are coupled to the connector by a signal path; and 
 an antenna in the shaft between the electrical components and the connector, wherein the shaft includes a metal tube with an opening in which the antenna is mounted and includes a plastic outer tube that covers the metal tube and that covers the antenna in the opening. 
 
     
     
       19. The computer stylus defined in  claim 18  wherein the antenna comprises an inverted-F antenna having a resonating element arm, a ground that is coupled to the metal tube by conductive adhesive, and a return path that extends between the resonating element arm and the ground. 
     
     
       20. The computer stylus defined in  claim 19  wherein the antenna comprises a feed, the computer stylus further comprising a coaxial cable coupled to the feed. 
     
     
       21. The computer stylus defined in  claim 20  wherein the metal tube has an additional opening and wherein the coaxial cable passes through the additional opening. 
     
     
       22. The computer stylus defined in  claim 21  further comprising a strip of conductive foam that covers at least some of the coaxial cable. 
     
     
       23. The computer stylus defined in  claim 22  further comprising a removable cap that covers the connector. 
     
     
       24. The computer stylus defined in  claim 23  further comprising an inner plastic tube that supports the antenna in the opening, wherein the antenna comprises metal traces on the inner plastic tube.

Description:
BACKGROUND 
     This relates generally to wireless communications circuitry and, more particularly, to wireless communications circuitry for elongated wireless devices such as computer styluses. 
     It can be challenging to form wireless circuitry for electronic equipment. For example, it can be difficult to incorporate wireless components such as antennas into compact portable devices such as tablet computer styluses. If care is not taken, the presence of conductive structures will adversely affect antenna performance. Poor antenna performance can lead to the use of increased transceiver power and reduced battery life. Poor antenna performance can also degrade wireless functionality. 
     It would therefore be desirable to be able to provide improved wireless circuitry for wireless devices such as computer styluses. 
     SUMMARY 
     A computer stylus may be provided that supplies input to an electronic device such as a tablet computer. The stylus may have an elongated body with a tip and an opposing end. The opposing end of the stylus may include components such as a connector and antenna. The connector may be covered with a cap. 
     The antenna may be an inverted-F antenna, a ring antenna or other antenna that wraps around the body of the stylus, or may be an antenna of another type. Antenna structures may be formed on flexible printed circuits or may be formed from metal traces on plastic support structures. If desired, metal structures for an antenna may be supported using a molded plastic support that forms a three-dimensional antenna. 
     Metal and plastic tubes may be used in forming the body of the stylus. A metal tube may have an opening in which an antenna is mounted. A plastic tube may serve as an outer housing for the stylus and may cover the metal tube and the opening in which the antenna is mounted. An inner plastic tube may serve as a support structure for antenna traces. 
     A transmission line such as a cable may be coupled to an antenna feed. The cable may pass through an opening in the metal tube and may be covered using a strip of conductive foam. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative computer and associated computer stylus in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of an illustrative stylus with wireless communications circuitry in accordance with an embodiment. 
         FIG. 3  is a diagram of illustrative wireless circuitry for use in a stylus in accordance with an embodiment. 
         FIG. 4  is a diagram of an illustrative inverted-F antenna for a stylus in accordance with an embodiment. 
         FIG. 5  is a diagram of an illustrative planar inverted-F antenna in accordance with an embodiment. 
         FIG. 6  is a diagram of an illustrative monopole antenna in accordance with an embodiment. 
         FIG. 7  is a diagram of an illustrative loop antenna in accordance with an embodiment. 
         FIG. 8  is a diagram of an illustrative ring antenna in accordance with an embodiment. 
         FIG. 9  is a perspective view of an illustrative antenna formed using laser direct structuring techniques in accordance with an embodiment. 
         FIG. 10  is a perspective view of an illustrative flexible printed circuit antenna in accordance with an embodiment. 
         FIG. 11  is a cross-sectional side view of an illustrative antenna with a metal resonating element mounted to a support structure in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of an illustrative antenna formed from printed conductive ink in accordance with an embodiment. 
         FIG. 13  is a perspective view of an illustrative antenna being fed using a coaxial cable in accordance with an embodiment. 
         FIG. 14  is a cross-sectional side view of an illustrative antenna being fed using a spring-loaded pin in accordance with an embodiment. 
         FIG. 15  is a cross-sectional side view of an illustrative antenna being fed using a spring in accordance with an embodiment. 
         FIG. 16  is a cross-sectional side view of an illustrative antenna being fed using a via that passes through a substrate in accordance with an embodiment. 
         FIG. 17  is a cross-sectional side view of a portion of an elongated body for a stylus in accordance with an embodiment. 
         FIG. 18  is a side view of an illustrative stylus having a tip and an opposing end at which an antenna has been formed in accordance with an embodiment. 
         FIG. 19  is a perspective view of an illustrative three-dimensional antenna of the type that may be mounted at the end of the stylus of  FIG. 18  in accordance with an embodiment. 
         FIG. 20  is a rear view of the antenna of  FIG. 19  showing where a conductive structure such as a magnet may be mounted over antenna traces in accordance with an embodiment. 
         FIG. 21  is a side view of a portion of the antenna of  FIG. 19  following attachment of a magnet to antenna traces on the antenna in accordance with an embodiment. 
         FIG. 22  is a cross-sectional side view of an illustrative stylus having a dielectric covering that covers an antenna located at an end of the stylus in accordance with an embodiment. 
         FIG. 23  is a cross-sectional side view of an illustrative stylus having an antenna that is formed at a location that is offset from the end of the stylus in accordance with an embodiment. 
         FIG. 24  is an exploded perspective view of an illustrative stylus with a removable cap and an antenna that is formed at a location that is offset from the end of the stylus in accordance with an embodiment. 
         FIG. 25  is a cross-sectional side view of an illustrative stylus with a removable cap and an antenna that offset from the end of the stylus in accordance with an embodiment. 
         FIG. 26  is a perspective view of an illustrative antenna for a stylus that is being feed with a cable that has been covered with a conductive foam in accordance with an embodiment. 
         FIG. 27  is a cross-sectional end view of an illustrative stylus antenna with a metal trace that wraps around most of a stylus body in accordance with an embodiment. 
         FIG. 28  is a cross-sectional end view of an illustrative stylus antenna with a metal trace that wraps around all of a stylus body in accordance with an embodiment. 
         FIG. 29  is a perspective view of an illustrative ring antenna of the type that may be used in forming a stylus antenna in accordance with an embodiment. 
         FIG. 30  is a side view of an illustrative antenna trace of the type that may be mounted on the side of a stylus at a location that is offset from the end of the stylus in accordance with an embodiment. 
         FIG. 31  is a cross-sectional side view of an illustrative stylus having a metal body structure with an opening for an antenna in accordance with an embodiment. 
         FIG. 32  is a perspective view of the metal body structure of  FIG. 31  in accordance with an embodiment. 
         FIG. 33  is a cross-sectional side view of a portion of a stylus body having antenna structures that are shorted to a metal tube in the stylus body in accordance with an embodiment. 
         FIG. 34  is a cross-sectional side view of a portion of a stylus in which an antenna is being fed using a cable that exits from the interior of a metal tube before being coupled to a feed for the antenna in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     A system that includes electronic equipment that communicates wirelessly is shown in  FIG. 1 . The equipment of  FIG. 1  includes electronic device  120  and electronic device  10 . Electronic equipment such as devices  120  and  10  may, in general, be computing devices such as laptop computers, computer monitors containing embedded computers, tablet computers, cellular telephones, media players, or other handheld or portable electronic devices, smaller devices such as wrist-watch devices, pendant devices, headphone or earpiece devices, devices embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature devices, televisions, computer displays that do not contain embedded computers, gaming devices, navigation devices, embedded systems such as a systems in which electronic equipment is mounted in kiosks or automobiles, computer accessories such as touch pads, computer mice, computer styluses, or other electronic accessories, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG. 1 , which is sometimes described herein as an example, device  120  is a tablet computer or other device with a touch screen and device  10  is a computer stylus. When a drawing program is running on tablet computer  120 , a user can use stylus  10  to draw on tablet computer  120  and to provide other input to tablet computer  120 . 
     Tablet computer  120  may include a housing such as housing  124  in which display  122  is mounted. Input-output devices such as button  126  may be used to supply input to tablet computer  120 . Display  122  may be a capacitive touch screen display or a display that includes other types of touch sensor technology. The touch sensor of display  122  may be configured to receive input from stylus  10 . 
     Stylus  10  may have a cylindrical shape or other elongated body that extends along longitudinal axis  26 . The body of stylus  10  may be formed from metal and/or plastic tubes and other elongated structures. Stylus  10  and tablet computer  120  may contain wireless circuitry for supporting wireless communications via wireless communications link  28 . As an example, stylus  10  may supply wireless input to tablet computer  120  via link  28  (e.g., information on settings in a drawing program or other software running on tablet computer  120 , input to select a desired on-screen option, input to supply tablet computer  120  with a touch gesture such as a stylus flick, input to draw a line or other object on display  122 , input to move or otherwise manipulate images displayed on display  122 , etc.). 
     Stylus  10  may have a tip such as tip  14 . Tip  14  may contain a conductive elastomeric member that is detected by the capacitive touch sensor of display  122 . If desired, tip  14  may contain active electronics (e.g., circuitry that transmits signals that are capacitively coupled into the touch sensor of display  122  and that are detected as touch input on the touch sensor). 
     Shaft portion  16  of stylus  10  may couple tip  14  of stylus  10  to opposing end  22  of stylus  10 . End  22  may contain a conductive elastomeric member, active electronics (e.g., circuitry that transmits signals that are capacitively coupled into the touch sensor of display  122  and that are detected as touch input on the touch sensor), buttons, a metal connector that mates with an external plug, or other input-output components. 
     A force sensor may be incorporated into tip  14  and/or opposing end  22  of stylus  10 . A force sensor may be used to measure how forcefully a user is pressing stylus  10  against the outer surface of display  122 . Force data may then be wirelessly transmitted from stylus  10  to tablet  120  so that the thickness of a line that is being drawn on display  122  can be adjusted accordingly or so that tablet  120  may take other suitable action. 
     If desired, stylus  10  may be provided with a clip to help attach stylus  10  to a user&#39;s shirt pocket or other object, may be provided with a magnet to help attach stylus  10  to a magnetic attachment point in device  120  or other structure, or may be provided with other structures that help a user attach stylus  10  to external objects. End  22  may have a removable cap, a data port connector to receive a cable (e.g., a cable that supplies power signals for charging a battery in stylus  10  and/or that supplies digital data), input-output devices (e.g., a button and/or a light-emitting diode or other light-based output device), or other components (e.g., metal structures). 
     Components such as components  18  may be formed on stylus  10  (e.g., on shaft  16  or elsewhere). Components  18  may include buttons, touch sensors, and other components for gathering input, light-emitting diodes or other components for producing output, etc. 
     Stylus  10  may include a metal tube or other conductive components in shaft portion  16 . The metal tube or other structures in stylus  10  may serve as an antenna ground for an antenna. An antenna resonating element for the antenna may be formed from metal traces on a printed circuit or other dielectric support structure and/or from other conductive structures. An antenna resonating element may be located in region  20 B of end region  22  or may be formed at a location such as region  20 A that is offset from the end of stylus  10 . In configurations in which an antenna is located in offset region  20 A, a connector or other components may be mounted in region  20 B. If desired, antennas for stylus  10  may be located elsewhere along body  16 , in tip region  14 , or in other suitable portions of device  10 . 
     A schematic diagram showing illustrative components that may be used in stylus  10  is shown in  FIG. 2 . As shown in  FIG. 2 , stylus  10  may include control circuitry such as storage and processing circuitry  30 . Storage and processing circuitry  30  may include storage such as 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 storage and processing circuitry  30  may be used to control the operation of stylus  10 . This processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processor integrated circuits, application specific integrated circuits, etc. 
     Storage and processing circuitry  30  may be used to run software on stylus  10 . The software may process input from buttons, sensors, and other input components. The software may also be used to provide output to a user (e.g., using light-emitting-diodes or other output components such as components  18  of  FIG. 1 ). To support interactions with external equipment such as tablet computer  120 , storage and processing circuitry  30  and other circuitry in stylus  10  may be used in implementing communications protocols. Communications protocols that may be implemented in stylus  10  include protocols for short-range wireless communications links such as the Bluetooth® protocol. If desired, other types of wireless communications links may be supported. The use of Bluetooth communications is merely illustrative. 
     Stylus  10  may include input-output circuitry  44 . Input-output circuitry  44  may include input-output devices  32 . Input-output devices  32  may be used to allow data to be supplied to stylus  10  and to allow data to be provided from stylus  10  to external devices such as tablet computer  120 . Input-output devices  32  may include user interface devices, data port devices, and other input-output components. For example, input-output devices  32  may include touch screens, displays without touch sensor capabilities, buttons, joysticks, scrolling wheels, touch pads, microphones, cameras, speakers, status indicators, light sources, audio jacks and other audio port components, digital data port devices, light sensors, accelerometers or other components that can detect motion and stylus orientation relative to the Earth, capacitance sensors, proximity sensors (e.g., a capacitive proximity sensor and/or an infrared proximity sensor), magnetic sensors, and other sensors and input-output components. 
     Input-output circuitry  44  may include wireless communications circuitry  34  for communicating wirelessly with external equipment. Wireless communications circuitry  34  may include radio-frequency (RF) transceiver circuitry formed from one or more integrated circuits, power amplifier circuitry, low-noise input amplifiers, passive RF components, one or more antennas  40 , transmission lines, and other circuitry for handling RF wireless signals. 
     Wireless communications circuitry  34  may include radio-frequency transceiver circuitry  90  for handling wireless communications in the 2.4 GHz Bluetooth® communications band or other suitable communications bands. Bluetooth signals or other wireless signals may be transmitted and/or received by transceiver circuitry  90  using one or more antennas such as antenna  40 . Antennas in wireless communications circuitry  34  may be formed using any suitable antenna types. For example, antennas for stylus  10  may include antennas with resonating elements that are formed from loop antenna structures, patch antenna structures, inverted-F antenna structures, slot antenna structures, planar inverted-F antenna structures, helical antenna structures, ring antennas, monopole antennas, hybrids of these designs, etc. If desired, one or more of the antennas in stylus  10  may be cavity-backed antennas. 
     Transmission line paths may be used to couple antenna  40  to transceiver circuitry  90 . Transmission lines in stylus  10  may include coaxial cable paths, microstrip transmission lines, stripline transmission lines, edge-coupled microstrip transmission lines, edge-coupled stripline transmission lines, transmission lines formed from combinations of transmission lines of these types, etc. Filter circuitry, switching circuitry, impedance matching circuitry, and other circuitry may be interposed within the transmission lines, if desired. 
     As shown in  FIG. 3 , transceiver circuitry  90  in wireless circuitry  34  may be coupled to antenna  40  using paths such as path  92 . Wireless circuitry  34  may be coupled to control circuitry  30 . Control circuitry  30  may be coupled to input-output devices  32 . Input-output devices  32  may supply output from stylus  10  and may receive input from sources that are external to stylus  10 . 
     To provide antenna  40  with the ability to cover communications frequencies of interest, antenna  40  may be provided with circuitry such as filter circuitry (e.g., one or more passive filters and/or one or more tunable filter circuits). Discrete components such as capacitors, inductors, and resistors may be incorporated into the filter circuitry. Capacitive structures, inductive structures, and resistive structures may also be formed from patterned metal structures (e.g., part of an antenna). If desired, antenna  40  may be provided with adjustable circuits such as tunable components  102  to tune antenna  40  over communications bands of interest. Tunable components  102  may include tunable inductors, tunable capacitors, or other tunable components. Tunable components such as these may be based on switches and networks of fixed components, distributed metal structures that produce associated distributed capacitances and inductances, variable solid state devices for producing variable capacitance and inductance values, tunable filters, or other suitable tunable structures. During operation of stylus  10 , control circuitry  30  may issue control signals on one or more paths such as path  88  that adjust inductance values, capacitance values, or other parameters associated with tunable components  102 , thereby tuning antenna  40  to cover desired communications bands. Configurations in which antenna  40  is free of tunable components may also be used. 
     Path  92  may include one or more transmission lines. As an example, signal path  92  of  FIG. 3  may be a transmission line having a positive signal conductor such as line  94  and a ground signal conductor such as line  96 . Lines  94  and  96  may form parts of a coaxial cable or a microstrip transmission line (as examples). A matching network formed from components such as inductors, resistors, and capacitors may be used in matching the impedance of antenna  40  to the impedance of transmission line  92 . Matching network components may be provided as discrete components (e.g., surface mount technology components) or may be formed from housing structures, printed circuit board structures, traces on plastic supports, etc. Components such as these may also be used in forming filter circuitry in antenna  40 . 
     Transmission line  92  may be coupled to antenna feed structures associated with antenna  40 . As an example, antenna  40  may form an inverted-F antenna, a slot antenna, a hybrid inverted-F slot antenna or other antenna having an antenna feed with a positive antenna feed terminal such as terminal  98  and a ground antenna feed terminal such as ground antenna feed terminal  100 . Positive transmission line conductor  94  may be coupled to positive antenna feed terminal  98  and ground transmission line conductor  96  may be coupled to ground antenna feed terminal  92 . Other types of antenna feed arrangements may be used if desired. The illustrative feeding configuration of  FIG. 3  is merely illustrative. 
       FIG. 4  is a diagram of illustrative inverted-F antenna structures that may be used in implementing antenna  40  for stylus  10 . Inverted-F antenna  40  of  FIG. 4  has antenna resonating element  106  and antenna ground  104 . Antenna resonating element  106  may have a main resonating element arm such as arm  108 . The length of arm  108  may be selected so that antenna  40  resonates at desired operating frequencies. For example, the length of arm  108  may be a quarter of a wavelength at a desired operating frequency for antenna  40  (e.g., 2.4 GHz). Antenna  40  may also exhibit resonances at harmonic frequencies. 
     Main resonating element arm  108  may be coupled to ground  104  by return path  110 . Antenna feed  112  may include positive antenna feed terminal  98  and ground antenna feed terminal  100  and may run parallel to return path  110  between arm  108  and ground  104 . If desired, inverted-F antennas such as illustrative antenna  40  of  FIG. 4  may have more than one resonating arm branch (e.g., to create multiple frequency resonances to support operations in multiple communications bands) or may have other antenna structures (e.g., parasitic antenna resonating elements, tunable components such as components  102  of  FIG. 3  to support antenna tuning, etc.). In mounting antenna  40  in stylus  10 , the structures of antenna  40  may be curved. For example, ground  104  and/or resonating element  106  may be formed from metal that wraps around longitudinal axis  26  of stylus  10 . 
     As shown in  FIG. 5 , antenna  40  may be a planar inverted-F antenna (e.g., arm  108  may be formed from planar metal structures that lie above portions of ground  104 . Feed  112  may be formed from an arm that extends downwards from planar element  108  towards ground  104 . Return path  110  may be formed from a planar metal wall extends between planar arm  108  and ground  104  in parallel with feed  112 . 
     In the example of  FIG. 6 , antenna  40  is a monopole having a monopole resonating element  106 . Monopole resonating element  106  is formed from a strip of metal such as metal monopole arm  108 ). Metal monopole arm  108  extends from positive feed terminal  98  away from ground  104  and ground feed terminal  100 . The length of monopole arm  108  may be adjusted to cover a frequency range of interest (e.g., the length of monopole element may be a quarter of a wavelength at the operating frequency of interest). 
     If desired, antenna  40  may be formed from a loop antenna such as loop antenna  40  of  FIG. 7 . Loop antenna  40  may have a resonating element  106  that is formed from a loop of conductive material extending between positive antenna feed terminal  98  and ground antenna feed terminal  100 . 
       FIG. 8  shows how antenna  40  may be a ring antenna. Ring antenna  40  of  FIG. 8  has a positive antenna feed terminal such as feed terminal  98  and a ground antenna feed terminal such as feed terminal  100 . Positive antenna feed terminal  98  is coupled to ring antenna resonating element  106  (e.g., a metal structure that extends in a ring around the body of stylus  10 , etc.). Ground antenna feed terminal  100  is coupled to ground  104 . 
     Other types of antenna may be used in forming antenna  40  for stylus  10  if desired (e.g., slot antennas, helical antennas, patch antennas, etc.). The configurations of  FIGS. 4, 5, 6, 7, and 8  are merely illustrative. 
     Antenna  40  may be formed from conductive structures such as metal structures. The metal structures of antenna  40  may be metal coating layers, portions of a device housing or other structural metal member, portions of a metal tube, metal foil, wires, or other metal structures. 
     In the illustrative configuration of  FIG. 9 , antenna  40  includes three-dimensional metal arm  108  on three-dimensional (non-planar) dielectric support  130 . Dielectric support  130  may be, for example, a support formed from a dielectric such as plastic (e.g., molded plastic). The plastic material that forms support  130  may be provided with metal particles or other filler material that sensitizes support  130  to exposure from laser light. Following exposure to laser light, portions of support  130  that have been exposed to laser light will promote coating with electroplated metal, whereas portions of support  130  that have not been exposed to laser light will not promote electroplating metal growth. With this approach, which may sometimes be referred to as laser direct structuring (LDS), metal structures such as metal antenna arm  108  of  FIG. 9  may be deposited using electroplating. The metal antenna structures that are grown in this way can be three-dimensional (i.e., a curved surface such as the curved surface of illustrative support structure  130  of  FIG. 9  can be coated with metal). Use of a three-dimensional antenna structure may help create a desired antenna radiation pattern for antenna  40  while accommodating antenna  40  within a housing of a desired shape. 
     In the example of  FIG. 10 , metal traces for antenna arm  108  have been deposited and patterned on a flexible substrate such as flexible substrate  132 . The metal for forming antenna structures such as arm  108  can be deposited as a blanket metal coating and subsequently patterned using photolithography and metal etching (as an example). Flexible substrate  132  may be a flexible printed circuit formed from a polyimide substrate or a flexible layer of other polymer material. When installed in stylus  10 , flexible substrate  132  may wrapped around the elongated body of stylus  10 . 
       FIG. 11  is an exploded perspective view of an illustrative antenna arm  108  for antenna  40  that is formed from a metal member (e.g., stamped metal foil, etc.) that is attached to dielectric support member  134  using adhesive  136 . Support member  134  may be formed from plastic or other dielectric materials and may form a portion of the elongated body of stylus  10 . 
       FIG. 12  is a diagram showing how metal antenna arm  108  and other antenna structures may be formed by printing conductive ink  144  onto the surface of dielectric support  138 . Dielectric support  138  may be a planar substrate such as a printed circuit substrate or may be a molded plastic support or other structure that has a three-dimensional shape. Ink-jet dispenser  140  may be controlled using computer-controlled positioner  142 . When moved in direction  146 , dispenser  140  may deposit metal ink or other conductive ink  144  onto support structure  138 , thereby forming a desired shape for antenna element  108  of antenna  40 . Conductive ink (e.g., binder material that contains metal particles or other conductive particles) may be applied to a support structure using ink-jet printing, screen printing, pad printing, spraying, dipping, dripping, painting, or other suitable deposition techniques. 
     The antenna metal structure fabrication techniques described in connection with FIGS.  9 ,  10 ,  11 , and  12  are merely illustrative. Antenna structures may be formed from portions of metal housings (e.g., metal tubes that form structures for the elongated body of stylus  10 ), internal metal members, metal traces on flexible printed circuits, three-dimensional metal traces (e.g., laser patterned traces) on molded plastic substrates and other three-dimensional dielectric substrates, metal wires, metal foil (e.g., metal foil that has been patterned into the shape of an antenna structure and that is attached to a support structure using adhesive, screws, or other attachment mechanisms). 
     Antenna  40  may be fed using a cable, a transmission line on a flexible printed circuit, or other suitable feed arrangements. 
     In the example of  FIG. 13 , transmission line  92  has been implemented using a coaxial cable. An outer conductor in the cable has been shorted to ground  104  at ground feed terminal  100 . An inner conductor in the cable has been shorted to positive feed terminal  98 . Solder, welds, conductive adhesive, or other conductive coupling mechanisms may be used to couple transmission line  92  to antenna  40 . 
       FIG. 14  is a cross-sectional side view of antenna  40  showing another illustrative feed arrangement. In the example of  FIG. 14 , antenna  40  includes metal trace  154  on dielectric substrate  156 . Transmission line  92  includes signal conductor  150 . Spring-loaded pin  152  serves as a feed pin. Pin  152  may be soldered or otherwise electrically and mechanically coupled to signal line  150 . A spring in pin  152  may cause a protruding portion of pin  152  to press against metal antenna traces  154 , thereby completing an antenna feed connection for a positive feed terminal or a ground feed terminal. 
     As shown in  FIG. 15 , a spring such as spring  160  may be used in forming an antenna feed connection. Antenna  40  may include dielectric substrate  164  and antenna traces  162 . Transmission line  92  may include conductive signal line  158 . Springs such as spring  160  may be coupled to signal line  158  (e.g., using solder, welds, conductive adhesive, fasteners, etc.). Spring  160  may apply a biasing force to antenna trace  162  to form a positive or ground antenna feed connection. 
     In the illustrative configuration of  FIG. 16 , antenna  40  and transmission line  92  are formed from a common substrate. Substrate  166  is formed from a printed circuit or other dielectric and has a first portion in which transmission line conductor  168  is used in forming transmission line  92  and a second portion in which antenna trace  170  is used in forming a resonating element structure and/or ground structure for antenna  40 . One or more vias such as via  172  may extend through substrate  166  and may be used in forming positive and ground antenna feed connections. 
     The housing of stylus  10  may be formed from metal, plastic, carbon-fiber composites and other fiber composites, glass, ceramic, other materials, and combinations of these materials. A cross-sectional side view of a shaft portion  16  of the elongated body of stylus  10  is shown in  FIG. 17 . As shown in  FIG. 17 , electrical components  190  may be mounted within interior cavity  188  of the body of stylus  10 . Components  190  may include integrated circuits, sensors, battery structures, connectors, switches, and other circuitry (e.g., control circuitry  30  and/or input-output circuitry  44  of  FIG. 1 ). Components  190  may be mounted on one or more substrates such as substrate  186 . Substrate  186  may be a dielectric support structure such as a printed circuit (e.g., a rigid printed circuit formed from a rigid printed circuit board material such as fiberglass-filled epoxy or a flexible printed circuit formed from a flexible sheet of polyimide or other flexible polymer layer). 
     Interior cavity  188  may be surrounded by one or more layers of material such as layers  180 ,  182 , and  184 . These layers of material may form concentric cylindrical tubes and may be formed from metal, plastic, glass, ceramic, other materials, and/or two or more of these materials. As an example, outer layer  180  may form a plastic tube that serves as a cosmetic exterior for stylus  10 , intermediate layer  182  may form a metal tube that provides stylus  10  with structural support, and inner layer  184  may form a plastic tube that serves as a support structure. In general, tube  180  may be formed from metal, plastic, or other materials, tube  182  may be formed from metal, plastic, or other materials, and tube  184  may be formed from metal, plastic, or other materials. With another illustrative arrangement, inner tube  184  may be omitted, tube  180  may be formed from metal, plastic, or other materials and tube  182  may be formed from metal, plastic, or other materials. Configurations in which shaft  16  includes a single tube or includes solid portions without significant interior cavity portions may also be used. 
     As shown in the cross-sectional side view of stylus  10  of  FIG. 18 , antenna  40  may be formed at end  22  of stylus  10 . With this type of arrangement, the risk of inadvertently blocking antenna  40  with the hand of a user may be minimized. 
     A perspective view of an illustrative antenna for mounting at end  22  of stylus  10  of  FIG. 18  is shown in  FIG. 19 . As shown in  FIG. 19 , antenna  40  may have metal traces formed on a three-dimensional support structure such as molded plastic support  200 . Antenna  40  may be an inverted-F antenna and the metal traces may include a portion that forms antenna resonating arm  108  (e.g., arm  108  of  FIG. 4 ), return path  110  (e.g., return path  110  of  FIG. 4 ), and antenna ground  104  (e.g., ground  104  of  FIG. 4 ). Screw  206  and/or other conductive coupling structures may be used to couple ground trace portion  104  to a metal tube in stylus  10  or other antenna ground structures. Transmission line  92  may be implemented using a coaxial cable having a ground conductor coupled to ground terminal  100  on ground  104  and a positive conductor coupled to positive antenna feed terminal  98 . 
     If desired, the rear of antenna  40  may be formed from a metal trace that is sufficiently large to receive a component such as magnet  202  (e.g., when magnet  202  is installed on the rear of antenna  40  in direction  204  using adhesive or other attachment mechanisms). A rear view of antenna  40  of  FIG. 19  is shown in  FIG. 20 . Dashed lines  202 ′ of  FIG. 20  show where magnet  202  may be mounted. During operation, antenna currents may flow through magnet  202  (i.e., magnet  202  may form part of the antenna). The upper surface of antenna support structure  200  may have a dome-shaped configuration to accommodate mounting within a domed end portion of stylus  10  or may have other suitable shapes. 
       FIG. 21  is a cross-sectional side view of magnet  202  mounted to arm  108  on support structure  200 . As shown in  FIG. 21 , conductive adhesive  208  may be used in mounting magnet  202  to antenna  40 . If desired, magnet  202  may be omitted (e.g., when a clip or other structure is present in stylus  10  to help secure stylus  10  when not in use). 
     As shown in the cross-sectional side view of end  22  of stylus  10  of  FIG. 22 , an antenna such as antenna  40  of  FIG. 19  may be covered with one or more dielectric layers such as stylus housing  210 . Housing  210  may be formed from plastic or other radio-transparent material. In the example of  FIG. 22 , antenna  40  has been formed at the end of stylus  10 . If desired, antenna  40  may be located at a position that is offset from the end of stylus  10 . As shown in  FIG. 23 , for example, antenna  40  may be mounted within stylus  10  at a location such as location  20 A that is not directly adjacent to the end of stylus  14  (i.e., location  20 A is offset from end  212  and portion  20 B is interposed between antenna  40  and end  212 ). 
     As shown in  FIG. 24 , stylus  10  may have a removable cap such a cap  218 . Cap  218  may be attached and removed from end  22  of stylus  10 . Stylus  10  may have a connector such as connector  214 . Connector  214  may have contacts (pins)  216  that mate with a corresponding connector (e.g., a connector on a companion electronic device). Connector  214  may be used to recharge a battery in stylus  10 , to convey settings and other information to stylus  10  from external equipment, and/or to convey data or power from stylus  10  to external equipment. Antenna  40  may be located at a position such as position  20 A that is recessed from connector  214 . 
     A cross-sectional side view of an illustrative stylus with a cap is shown in  FIG. 25 . As shown in  FIG. 25 , stylus  10  may have outer housing  232  to which cap  218  may be attached (e.g., by friction) or detached (e.g., by pulling cap  218  away to expose connector  214 ). Connector  214  may be formed from a printed circuit or other structure to which support circuitry  222  (e.g., integrated circuits, etc.) may be mounted. A flexible printed circuit or other signal path such as signal path  224  may be used to couple connector  214  and associated connector circuitry  222  to printed circuit  226  and components  228  on printed circuit  226 . Components  228  may include circuitry for forming control circuitry  30  and input-output circuitry  44  of  FIG. 2 . 
     Antenna  40  may be located in a region such as region  20 A that is offset from the end of stylus  10  (e.g., non-antenna region  20 B may be interposed between the end of stylus  10  and antenna region  20 A). 
     Metal tube  220  may be mounted within housing  232 . In region  20 A, metal tube  220  (or most of metal tube  220 ) may be absent and antenna  40  may be mounted under housing  232 . Housing  232  may be a plastic tube that is radio-transparent. By removing metal tube  220  from region  20 A (e.g., by forming an opening in tube  220 ), portion  222  of housing  232  may form an antenna window for antenna  40 . Metal tube  220  may be absent from region  20 B or portions  220 ′ of metal tube  220  may be located in region  20 B. 
     As shown in  FIG. 26 , antenna  40  of  FIG. 25  may be formed from metal traces on a dielectric support structure such as support structure  234 . Support structure  234  may be a plastic tube or other dielectric support structure (e.g., an inner tube in a multi-tube arrangement). The antenna traces formed on support  234  may include antenna resonating element arm  108 , metal structures for feed  112 , a metal trace forming return path  110 , and metal traces that couple antenna  40  to ground  104 . Transmission line  92  may be a coaxial cable having an outer connector coupled to ground feed terminal  100  and an inner conductor coupled to positive feed terminal  98  (as an example). Metal tube  220  may be used in forming antenna ground  104  and may be shorted to a ground trace in the antenna traces on support  234 . If desired, cable  92  may be covered with a strip of conductive foam such as foam  236  or other conductive material (e.g., conductive fabric, metal foil, etc.). This may help ground and shield cable  92 . 
     The metal traces for antenna  40  may surround some or all of the circumference of stylus  10 .  FIGS. 27 and 28  are cross-sectional top views of stylus  10  in two different illustrative configurations. In the example of  FIG. 27 , the metal trace for antenna resonating element arm  108  extends around most but not all of the circumference of support  234 . In the example of  FIG. 28 , the metal trace for antenna resonating element arm (ring)  108  extends entirely around support  234 .  FIG. 29  shows how the metal trace for antenna resonating element  108  may be configured to form a ring antenna (i.e., a resonating element that extends entirely around support  234  as shown in the top view of  FIG. 28 ). Antennas such as ring antenna  40  of  FIG. 29  or the inverted-F antenna of  FIG. 26  may be formed in regions of stylus  10  such as region  20 A or other suitable regions. Antenna structures may be formed from patterned traces on a plastic support, from metal traces on a printed circuit that is wrapped around a plastic support, from metal foil structures that are attached to a plastic support, metal housing structures, or other suitable metal structures. 
       FIG. 30  is a side view of illustrative metal antenna traces for an inverted-F antenna that have been formed on support structure  234 . The antenna traces may include traces for forming arm  108 , return path  110 , feed  112 , and a strip of metal such as strip  104 ′ that can be shorted to metal tube  220  (see, e.g.,  FIG. 26 ) to form antenna ground using conductive adhesive  237 . 
     As shown in  FIG. 31 , metal tube  220  may have a cylindrical shape with a cut out portion forming an opening to accommodate antenna  40 . A perspective view of metal tube  220  of  FIG. 31  is shown in  FIG. 32 . As shown in  FIG. 32 , vertical portion  220 ″ may be used to attach ring-shaped upper portion  220 ′ to main portion  220 . 
     A cross-sectional side view of a wall portion of stylus  10  in the vicinity of antenna  40  is shown in  FIG. 33 . In the example of  FIG. 33 , dielectric support  234  has the shape of an inner tube. Antenna traces for antenna  40  such as ground trace  104 ′ and resonating element arm  108  may be formed on support structure  234 . In ground region  104 , metal tube  220  is shorted to trace  104 ′ using conductive adhesive  237 . Screw  250  may be used to attach metal tube  220  to support  234  and may help form an electrical connection between tube  220  (which can serve as antenna ground) and ground trace  104 ′. Plastic housing tube  232  may cover antenna  40  and may serve as the outermost layer of stylus  10 . 
     As shown in  FIG. 34 , printed circuit  226  of  FIG. 25  may have a connector such as connector  260 . Coaxial cable  92  may be coupled to radio-frequency transceiver circuitry on board  226  using connector  260 . Cable  92  may pass through opening  262  in metal tube  220  and may be coupled to antenna feed  112  through the opening in tube  220  that accommodates antenna  40 . Conductive adhesive  264  may help short the ground conductor of cable  92  to metal tube  220 . Cable  92  may be covered with a strip of conductive material such as conductive foam  236  of  FIG. 26  or conductive fabric, metal, or other material. 
     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: 20150706
Publication Date: 20170919
Grant Date: 20170919
Priority Date: 20150706
Inventors: JIANG YI
HUANG HUAN-CHU
PASCOLINI MATTIA
LI QINGXIANG
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/033", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/03545", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 56498776