Patent Publication Number: US-2022236592-A1

Title: Hinge Feed Antenna of Eyewear

Description:
RELATED APPLICATIONS 
     This patent application is a continuation of U.S. patent application Ser. No. 16/684,505, filed Nov. 14, 2019, which is herein incorporated by reference. 
    
    
     FIELD OF THE DESCRIBED EMBODIMENTS 
     The described embodiments relate generally to electronic eyewear. More particularly, the described embodiments relate to systems, methods, and apparatuses for a hinge feed antenna of electronic eyewear. 
     BACKGROUND 
     Eyeglasses generally include a temple arm and front frame. The mechanical connection between these two parts is hinge, which allow temple to rotate to around a 90 degrees angle with respect to the frame. Typically, the hinges are resilient and can tolerate more than a thousand times of bending force. 
     It is desirable to have methods apparatuses, and systems for a hinge feed antenna of electronic eyewear. 
     SUMMARY 
     An embodiment includes an apparatus. The apparatus includes a front frame, a temple arm, and a hinge rotatably connecting the front frame and the temple arm. For an embodiment, the temple arm includes a circuit assembly including at least a radio that supports wireless communication. For an embodiment, the front frame includes one or more antennas traces, wherein the hinge conductively connects the circuit assembly to the one or more antenna traces. The apparatus further includes an antenna tuner located between the circuit assembly and the hinge, wherein a rotation position of the temple arm is sensed, wherein the rotation position is dependent on an orientation of the front frame relative to the temple arm; and wherein the antenna tuner includes an impedance tuner for adaptively adjusting an input impedance of the impedance tuner based on the sensed rotation position of temple arm. 
     Another embodiment includes a method. The method includes forming one or more antennas by one or more conductive traces of a front frame of an eyewear in combination with a hinge of the eyewear, wherein the hinge is electrically conductive, and wherein the hinge rotatably connects the front frame and a temple arm, receiving or transmitting wireless communication through the one or more antennas, and generating, or receiving the wireless communication, by a circuitry assembly located in the temple arm that includes a radio that supports the wireless communication, wherein the radio is connected to the one or more antennas through the hinge. 
     Other aspects and advantages of the described embodiments will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows eyewear that includes an antenna formed by a conductive trace and a conductive hinge of the eyewear, according to an embodiment. 
         FIG. 2  shows eyewear that includes an antenna formed by conductive traces and a conductive hinge of the eyewear, according to an embodiment. 
         FIG. 3  shows eyewear that includes an antenna formed by a conductive trace, a conductive hinge, and an impedance tuner of the eyewear, according to an embodiment. 
         FIG. 4  shows eyewear that includes an antenna formed by conductive traces, a conductive hinge, and an impedance tuner of the eyewear, according to an embodiment. 
         FIG. 5  shows control of an impendence tuner of eyewear, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments described include methods, apparatuses, and systems for a hinge feed antenna of electronic eyewear. For an embodiment, the eyewear includes a conductive hinge that electrically connects electronic circuitry located within a temple arm of the eyewear with an antenna element located within a front frame of the eyewear. The conductive hinge in combination with the antenna element form an antenna which can be used by the electronic circuitry communicate wirelessly with an external computing device. 
       FIG. 1  shows eyewear  100  that includes an antenna  105  formed by a conductive trace  120  and a conductive hinge  130  of the eyewear  100 , according to an embodiment. The eyewear  100  includes a front frame  106  and a temple arm  108 , wherein the front frame  106  and the temple arm  108  are rotatably connected by the conductive hinge  130 . For an embodiment, the temple arm  108  includes a circuit assembly  110  that includes at least a radio. An electrical connection  140  connects the circuit assembly  110  to the conductive hinge  130 . As previously stated, the conductive hinge  130  in combination with a conductive trace  120  forms the antenna  105 . The antenna  105  in conjunction with the radio operate to form a wireless link  150  for supporting wireless communication, which allows the radio of the circuit assembly to communicate with an external radio, thereby allowing the circuit assembly  110  to communicate with an external computing device. 
     Generally, eyewear such as eyeglasses include the temple arm  108  and the front frame  106 . Further, the hinge (such as, hinge  130 ) provides a mechanical connection between the temple arm  108  and the front frame  106 , which allows the temple arm  108  to rotate around a 90 angle with the frame. 
     Unlike conventional eyeglasses, electronic eyeglasses such as AR (augmented reality) glasses may include sophisticated electronics. The physical size of the electronics may operate to limit the volume of the size of mechanical parts of the eyeglasses. A key industrial design differentiator of eye glasses is the stylish front frame with delicate size. Therefore, it can be desirable to place a PCB (printed circuit board) with ICs (integrated circuits) inside the temple&#39;s enclosures behind hinge to support the sophisticated electronics. 
     Further, AR glasses usually include WiFi or cellular wireless connectivity which requires at least 2 antennas for high throughput data service. Due to the constraints of volume in the temple&#39;s enclosure where the PCB and the ICs (including, for example an RFIC (radio frequency integrated circuit)) are placed, it is almost impossible to additionally place 2 antennas in the temple arm. For this reason, it may be desirable to place at least one antenna in the front frame and use RF cable to connect the antenna to the RFIC at temple arm. 
     Unfortunately, running coaxial cable or a flex PCB through the hinge is not a desirable way of connecting an RF signal of the RFIC to an antenna feed for electronic glasses. An RF coaxial cable is lossy, and most importantly, passing an RF coaxial cable through the hinge increases the hinge size in order to meet reliability/bending requirements, which usually in conflict with industrial design goals. 
     For at least some embodiments, the size and shape of the conductive hinge  130  is selected based at least in part on the carrier frequency(s) of communication signals passing through the wireless link  150 . For at least some embodiments, the size and shape of the conductive trace  120  is selected based at least in part on the carrier frequency(s) of communication signals passing through the wireless link  150 . As described, the antenna  150  is formed by the combination of the conductive trace  120  and the conductive hinge  130 . Accordingly, for an embodiment, the size and shape of combination of the conductive trace  120  and the conductive hinge  130  are selected based at least in part on the carrier frequency of electromagnetic signals communicated through the antenna  150 . 
     For at least some embodiments, the conductive hinge  130  is formed from a metallic material that electrically and mechanically contacts the conductive trace  120  so that the two parts work in conjunction as a radiating antenna. For an embodiment, the conductive trace  120  includes a metallic trace. For an embodiment, LDS (laser direct structure) technology is used to form the metal trace in, for example, an inner surface of front frame  106  near the hinge  130 . 
     For an embodiment, the temple arm  108  includes the PCB that includes the RFIC. For an embodiment, an inner surface of the temple arm  108  includes the electrical connection  140  which is implemented with conductive feed traces. For an embodiment, LDS (laser direct structure) technology is used to form the conductive feed traces. It is to be understood that LDS is one example of a method for forming the conductive traces, and the other methods of forming the conductive traces may be used. 
     For an embodiment, the conductive trace  120  forms a main radiator of the antenna  105 . For an embodiment, LDS technology is used to form the conductive trace  120  on an inner surface of the front frame  106 . It is to be understood that LDS is one example of a method for forming the conductive traces, and the other methods of forming the conductive traces may be used. 
     For at least some embodiments, the conductive hinge  130  includes a minimum of two frames of reference. A first frame of reference may include a static frame of reference (the front frame  106 ) and a second frame of reference (the temple arm  108 ) that moves relative to the static frame of reference (the front frame). Both the temple arm  108  and the front frame  106  include conductive elements (conductive hinge  130 , conductive trace  120 ) fixed in their frames of reference that together form the antenna  105 . As will be described, a number of discrete elements may be added to either frame of reference (front frame  106  or temple arm  108 ) for various different reasons. Structurally, additional elements can be included to provide access for other cable routing, or to provide for more complex motion than simple rotation, or for cosmetic purposes. However, a conductive path is maintained between the two frames of reference. 
     For an embodiment, the conductive hinge  130  is affixed to the front frame  106  and the temple arm  108  using a structural hinge pin on one side and a plastic barrel on the other, in which the plastic is conductive and formed using LDS technology. For another embodiment, the conductive hinge  130  is affixed to the front frame  106  and the temple arm  108  using a plastic hinge on both sides with LDS antenna surfaces that contact the conductive hinge  130 . For another embodiment, the conductive hinge  130  is affixed to the front frame  106  and the temple arm  108  using a metallic hinge assembly that is fastened to the eyewear  100  or embedded during an injection molding process. 
     For at least some embodiments, a conductive adhesive applied between the elements (that is, between the conductive hinge and the conductive trace  120  and/or the electrical connection  140 ) to ensure conductivity over time as parts of the conductive hinge  140  wear. 
     For at least some embodiments, the conductive hinge  130  includes a sliding or rolling contact inside one portion that maintains contact to the other. 
       FIG. 2  shows eyewear that includes an antenna formed by conductive traces and a conductive hinge of the eyewear, according to an embodiment. Specifically,  FIG. 2  further includes a second conductive trace  222 . Here, the combination of the conductive trace  120 , the second conductive trace  222 , and the conductive hinge  130  form the antenna  205  of eyewear  200 . 
     For at least some embodiments, dimensions of at least one of the conductive trace  120  or the second conductive trace  222  is selected based on a carrier frequency F c1  of wireless signals propagating through the wireless link  250 . For at least some embodiments, dimensions of the other of the conductive trace  120  or the second conductive trace  222  is selected based on another carrier frequency F c2  of wireless signals propagating through the wireless link  250 . By selectively forming the dimensions and shapes of the conductive traces  120 ,  222 , various (multiple) carrier frequencies or frequency channels of wireless communication can be supported. 
     For an embodiment, dimensions of conductive trace  120 , the dimensions of the second conductive trace  222 , and the dimensions of the conductive hinge  130  are selected for a single carrier frequency of wireless communication through the link  250 . For example, multiple antenna elements may be formed by the combination of the conductive trace  120 , the second conductive trace  222 , and the conductive hinge  130 , and the multiple antenna elements can support MIMO (multiple-input, multiple-output) wireless communication over a single frequency channel. 
     The dimensions of the conductive trace  120 , the dimensions and shapes of the second conductive trace  222 , and the dimensions and shapes of the conductive hinge  130  can be determined through experimentation or simulation to ensure that the antenna  205  supports reception or transmission of electromagnetic waves of the desired frequencies. 
     For at least some embodiments, the conductive (metal) hinge  130  bridges the two parts of traces (that is, the conductive trace  120  and the second conductive trace  222 ). As previously described, the conductive trace  120  and the second conductive trace  222  function together to form the antenna  205 . 
     For an embodiment, the electrical contact between the PCB of the circuit assembly  110  and a conductive trace of the electrical connection  140  includes a spring contact. For an embodiment, the spring facilitates an electrical connection between an RFIC of the circuit assembly to the antenna  205 . 
       FIG. 3  shows eyewear  300  that includes an antenna  305  formed by a conductive trace  120 , a conductive hinge  130 , and an impedance tuner  350  of the eyewear, according to an embodiment. For at least some embodiments, the conductive hinge  130  provides comfort for users of the eyewear  300  with different head sizes by affording the temples a greater range of movement. That is, for at least some embodiments, the conductive hinge  130  does not limit the user to a 90 degrees angle. That is, the conductive hinge  130  is adapted to be adjusted to angles that vary both less than and/or greater than 90 degrees. 
     For at least some embodiments, rotation by the conductive hinge  130  of the angle between the front frame  106  and the temple arm  108  causes an impedance that the circuit assembly  110  drives through the electrical connection  140  to change with the rotation. Accordingly, an impedance mismatch will occur between the circuit assembly  110  and the conductive hinge  130  as the temple arm  108  is rotated by the conductive hinge  130  relative to the front frame  106 . The impedance mismatch causes less RF energy to be delivered to the antenna  305  formed by the conductive traces  120 ,  222  and the conductive hinge  130 . 
     At least some embodiments include inserting an impedance tuner  350  between the conductive antenna  130  and the circuit assembly  110  to mitigate the impedance mismatch and the energy loss caused by rotation of the conductive hinge  130 . That is, for at least some embodiments, the impedance tuner  350  includes a circuit in which the input impedance of the impedance tuner  350  is adaptively adjusted. For an embodiment, the input impedance of the impedance tuner  350  is adaptively adjusted based on the sensed rotation of the angle between the front frame  106  and the temple arm  108 . The resulting adjustment to the input impedance of the impedance tuner  350  is that the circuit assembly  110  drives an input impedance that is more uniform during rotation of the conductive hinge  130  than if the impedance tuner  350  was not included between the conductive hinge  130  and the circuit assembly  110 . That is, the impedance tuner mitigates the effects of impedance detuning of the conductive hinge  130  due to different temple arm positions. 
     For an embodiment, the sensing of the rotation includes sensing discrete angles of the rotation. For example, for an embodiment, the sensing includes “open” and “closed”. That is, the sensing determines that the temple arm  108  is approximately 90 degrees (open) relative to the front frame, or the sensing determines that the temple arm  108  is approximately 0 degrees (closed) relative to the front frame  106 . Therefore, the sensing is binary and only includes two sensed positions of the temple arm  108  relative to the front frame  106 . The sensed position in then used to adjust the impedance of the impedance tuner to mitigate variation of the input impedance faced by the circuit assembly during rotations of the temple arm  108  relative to the front frame  106 . 
     For at least some embodiments, more than two discrete angles of rotation can be sensed. That is, there may be N discrete sensed angles of the rotation. Each of the N discrete sensed angles are fed back to the impedance tuner  350  to accordingly adjust the input impedance faced by the circuit assembly during rotations of the temple arm  108  relative to the front frame  106 . 
     At least some embodiments include a continuous analog sensing of the rotations of the temple arm  108  relative to the front frame  106 . Again, the sensed angle is fed back to the impedance tuner  350  to adjust the input impedance. 
       FIG. 4  shows eyewear that includes an antenna  405  formed by conductive traces, a conductive hinge, and an impedance tuner of the eyewear, according to an embodiment. This embodiment shows the impedance tuner  350  adapted to mitigate the effects of the changing impedance of the conductive hinge  130  when forming an antenna in conjunction with the conductive trace  120  and the second conductive trace  222 . 
       FIG. 5  shows control of an impendence tuner  570  of eyewear, according to an embodiment. As previously described, a rotation of the temple arm relative to the front frame is sensed ( 580 ). The sensed rotation is fed back to an impedance tuner  570  for controlling an input impedance faced by the circuit assembly  110 . 
     For an embodiment, the impedance tuner  570  includes pre-match circuitry  575  that initially matches the input impedance with the circuit assembly  110  for a given rotation position. As the temple arm moves relative to the front frame away from the given rotation position, additional circuitry of the impedance tuner  570  is adjusted to mitigate variation of the input impedance of the impedance tuner  570 . 
     As shown, the additional circuitry of the impedance tuner  570  can include switches that switch in or out circuit elements, and/or an adjustable reactance. The switching and adjusting varies the input impedance to mitigate variations in the input impedance of the impedance tuner  570 . 
     For at least some embodiments, the hinge element itself includes of a minimum of two frames of reference. A first reference may be a static frame of reference (the front frame) and which is moving relative to it (the arm). The two frames of reference include conductive elements fixed in their frames of reference that together form an antenna. A number of discrete elements may be added to either frame of reference for various reasons: structural, or to provide access for other cable routing, or to provide for more complex motion than simple rotation, or for cosmetic purposes. In any of these cases, a conductive path needs to be maintained between the two frames of reference. 
     Various configurations of the conductive hinge are possible, and methods of attaching the hinge to the front frame and the temple arm. For an embodiment, the hinge includes a structural hinge pin on one side and a plastic barrel on the other, in which the plastic has been made conductive using LDS (laser direct structure) technology. For an embodiment, the hinge includes a metal hinge assembly that could be made to be fastened to the rest of the device (front frame of temple arm) or embedded during an injection molding process. For at least some embodiments, a conductive grease is applied between the elements (movable elements of the hinge) to ensure conductivity over time as parts wear. For an embodiment, the hinge includes a sliding or rolling contact inside one portion that maintains contact to the other. Further, at least some embodiments include a combination of above. 
     Given that glasses hinges tend to be either fully opened or fully closed, there are a few possible implementations for sensing or detecting the position of the temple arm relative to the front frame. The sensors for detecting the hinge orientation do not need to be integral to the hinge. For example, the proximity of the end of the temple arm opposite the hinge could be sensed when it is near the front frame when the hinge is fully closed. 
     For at least some embodiments, the antenna is tuned to discrete states, such as fully open (on head), fully open (off head), fully closed, fully closed inside case, etc. In this case, a number of sensors can be used to detect open versus closed and a proximity to other objects. Possible sensor includes, but are not limited to a limit switch, optical detectors, hall effect or reed switches, and/or capacitive sensors. 
     At least some embodiments include detecting a location of the eyewear, or detecting that the eyewear is either on of off the user&#39;s head. Possible sensor includes, but are not limited to a capacitive sensor (to sense proximity of the user), a motion sensor/accelerometer (thereby sensing if on the user&#39;s head or off the head a in static motion), electrical contact with case charger (thereby indicating the eyewear is within a case). If the eyewear is sensed near a user&#39;s head, the assumption can be made that the temple arm is extended relative to the front frame. If the eyewear is sensed to be in electrical contact with a charger, the assumption can be made that the temple arm is closed relative to the front frame. 
     At least some embodiments include analog sensing of the relative position of the front frame with the temple, which indicates the rotation of the hinge. Possible analog sensors include, but are not limited to a hall effect sensor, a flex or strain sensor on flexible element, an optical sensor, a rotary encoder (magnetic or optical), physical rotary potentiometer, and/or a number of limit switches and interpolation between the limit switches. These sensors and detector operate to continuously (continuously from a closed position of the temple arm relative to the front frame to an open position of the temple are relative to the front frame) detect or sense the temple are position relative to the front frame. 
     Although specific embodiments have been described and illustrated, the embodiments are not to be limited to the specific forms or arrangements of parts so described and illustrated. The described embodiments are to only be limited by the claims.