Patent Publication Number: US-2023135052-A1

Title: Antenna receiving apparatus and electronic watch

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. application Ser. No. 17/330,674, filed on May 26, 2021 which is based upon and claims the benefit of priority under 35 USC 119 of Japanese Patent Application No. 2020-092797, filed on May 28, 2020, the entire disclosure of which, including the description, claims, drawings, and abstract, is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure relates to an antenna receiving apparatus and an electronic watch. 
     2. Description of the Related Art 
     In most electronic devices that perform wireless communication, and especially in small portable electronic devices, an antenna is provided inside a case. JP 2019-124641 describes when radio waves with a plurality of wavelengths are received, a plurality of antennas may be provided according to each wavelength. 
     BRIEF SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, an antenna receiving apparatus includes: a first antenna; a second antenna that is synchronized with a frequency band different from the first antenna; a substrate that includes a receiving circuit connected to each of the first antenna and the second antenna; and a back lid that includes a conductor, wherein the conductor is in at least a portion of the back lid, wherein, the substrate includes a grounding surface of the first antenna, the substrate and the second antenna are positioned between the first antenna and the back lid, and the second antenna is positioned on a side of the substrate opposite of the first antenna, and the second antenna is electrically connected to the conductor of the back lid and grounded. 
     According to another aspect, an electronic watch includes, the above antenna receiving apparatus, a timekeeper that counts present time; and a controller which corrects the present time counted by the timekeeper based on the radio wave received by at least the first antenna and/or the second antenna. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG.  1    is a plan view showing an exterior appearance of an electronic watch. 
         FIG.  2    describes a relation of positions of antennas. 
         FIG.  3 A  shows a portion of a cross-section of the electronic watch. 
         FIG.  3 B  shows a portion of a cross-section of the electronic watch. 
         FIG.  4    shows an antenna element. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention are described with reference to the drawings. 
       FIG.  1    is a plan view showing an exterior appearance of an electronic watch  1  including an antenna receiving apparatus according to the present embodiment. 
     The electronic watch  1  includes a display  11 , a case  12  (see  FIG.  2   ), a bezel  13 , an exterior member  14  which covers a portion of the bezel  13 , a screw  15 , and a connector  16  which connects a belt to a main body. An upper surface of the electronic watch  1  includes the display  11  at a center and the bezel  13  in a position surrounding the display  11 . Press button switches B 1  to B 4  and a crown C 1  are provided on a side of the electronic watch  1 . The exterior member  14  is fixed to a case  12  by a screw  15  (see  FIG.  2   ). With this, the bezel  13  is fixed between the exterior member  14  and the case  12 . 
     The exterior member  14  includes the function to protect the main body of the electronic watch  1  including the press button switches B 1  to B 4  and the crown C 1  by the uneven surface and also includes the function as a decorative design. Material for the exterior member  14  may be, for example, resin. 
     The bezel  13  is a conducting member (normally a metal member) including a ring shaped structure. The bezel  13  operates as a first antenna in the electronic watch  1 . Here, the first antenna receives a radio wave (right handed circular polarization wave) from a positioning satellite (mainly a satellite regarding GPS (Global Positioning Satellite System)). 
     The press button switches B 1  to B 4  and the crown C 1  penetrate through the side of the case  12  and are projected outward. With this, the operation of pressing the press button switches B 1  to B 4  and the operation of pulling out and rotating the crown C 1  can be received. 
     The display  11  includes a digital display, and displays digitally. 
       FIG.  2    is a diagram describing the relation of the positions of the antennas. Similar to  FIG.  1   , this diagram is a plan view viewed from above. 
     Although not limited, the case  12  includes a structure with a tube shape such as a cylinder shape. The case  12  includes an operation module such as a substrate  21  and a battery  30  (see  FIG.  3   ) inside the tube and protects the units inside. Through holes for the above-described press button switches B 1  to B 4  and the crown C are provided on the side of the case  12 . 
     Two through holes  121  extending in a direction along the planar view direction (up and down direction) are positioned near a one o&#39;clock direction and an eleven o&#39;clock direction of the case  12 . Connecting pins  241  and  242  are inserted in these through holes  121 . The connecting pins  241  and  242  each electrically connect the bezel  13  as the antenna and the area on the substrate  21 . The connecting pins  241  and  242  do not need to be joined (fixed) to the case  12  or other portions. One end of the connecting pin  241  in contact with the bezel  13  is to be a feeding point and the other end transmits a receiving signal to a receiving circuit (here, a receiving circuit may include a circuit which only receives or a circuit which transmits and receives) connected through a signal line. The connecting pin  242  is connected to a grounding surface on the substrate  21 . 
     The case  12  includes an inserting groove  122  for an O ring on an outer side than the through holes  121 . The bezel  13  and the exterior member  14  are in contact and fixed in a state with the O ring inserted. With this, the structure becomes a waterproof structure. 
     An antenna element  214  (second antenna) is positioned near a four o&#39;clock direction on a back side of the substrate  21 , that is, on a side of the substrate  21  opposite to the bezel  13 . The antenna element  214  is an antenna which performs wireless radio communication with external devices at a close distance, here, communication (transmitting and receiving radio waves) by Bluetooth (registered trademark). That is, the antenna element  214  is an antenna which synchronizes with a frequency band different from the bezel  13 . Here, the antenna element  214  is a monopole antenna but is not limited to a straight line shape, and may have a bent shape (meander). The antenna element  214  is electrically connected to an area on the substrate  21  with a communicating circuit  213  (see  FIG.  3   ) positioned near the antenna element  214 . As described later, the antenna  214  is electrically connected and grounded from the grounding terminal on the substrate  21  to a back lid  17  (see  FIG.  3 B ). 
       FIG.  3 A  is a diagram showing a portion of a cross-section including the connecting pin  242  of the electronic watch  1  and  FIG.  3 B  is a diagram showing a portion of a cross-section including the antenna element  214 . That is, the cross-section shown in  FIG.  3 A  is the portion shown with a cross-section line AA in  FIG.  2   , and the cross-section shown in  FIG.  3 B  is the portion shown with a cross-section line BB in  FIG.  2   .  FIG.  4    is a diagram showing the antenna element  214 . 
     A display screen  111  and an optically transparent (normally transparent) protecting layer  112  (contact glass) which covers the display screen are positioned on the upper side of the substrate  21 . The protecting layer  112  covers the upper edge surface of the case  12 . A frame  22  (conducting supporter, storage) and a battery  30  which is fixed or supported by the frame  22  are positioned on the lower side of the substrate  21 . The lower edge surface of the case  12  is covered by the back lid  17 . The entire back lid  17  is a conducting member, but if a portion suitable as a grounding surface is a conductor, the remaining portion may be an insulator. 
     Some of the circuits on the substrate  21 , for example, a communicating circuit regarding the transmitting and receiving of the radio wave and the CPU which operates as a controller and performs control operations such as counting, displaying and correcting the date and time are covered by a shield case  211 . A shield case  211 , etc. protects the elements inside from electromagnetic waves and static electricity, and is a conductor with a box-type structure, for example. The other structures on the substrate  21 , for example, oscillating circuit, time keeper which counts the present date and time (present time) and nonvolatile memory can be positioned outside the shield case  211 , etc. 
     As shown in  FIG.  3 A , a satellite radio wave receiving module  212  including a receiver which receives the radio wave from the positioning satellite and a processor which processes the received radio wave is positioned in the shield case  211  near the connecting pins  241  and  242  on the upper surface side of the substrate. The satellite radio wave receiving module  212  performs a process in which the radio wave received by the receiver is demodulated by the processor and the signal is decoded by the processor so that the present date and time and the present position are specified. The controller on the substrate  21  may correct the date and time counted by the timekeeper based on the specified present date/time. 
     For example, the display screen  111  is a liquid crystal display screen, but the present embodiment is not limited to the above, and any type of liquid crystal may be used. Various displays are shown on the display screen  111  based on a control signal from the controller on the substrate  21 . 
     The connecting pin  242  is electrically connected to the grounding terminal  210  on the substrate  21 , and is connected to the grounding surface G spreading on the substrate  21  (here, the grounding surface G is displayed only near the connecting portion with the grounding terminal  210 ). When the substrate  21  is a layered substrate, the grounding surface may spread in an intermediate layer which is not exposed. Here, the grounding terminal  210  and the grounding surface G are clearly shown for the ease of description, but the actual thickness of the grounding terminal  210  and the grounding surface G may be sufficiently thin compared to the thickness of the substrate  21 . 
     The connecting pin  24  inserted in the through hole  121  of the case  12  includes a spring structure capable of expanding and contracting in an extending direction. When the electronic watch  1  is assembled and sealed, one end of the connecting pin  242  comes into contact with the substrate  21  and the other end comes into contact with the bezel  13  in a state in which the spring is contracted. With this, even if some impact is applied to the electronic watch  1 , the contact to both sides is maintained by tension of the spring. There are two widths in the through hole  121 , and the connecting pin  24  includes a head shape to fit in the two widths. With this, it is possible to prevent shift in the position in the left and right direction. 
     As described above, the bezel  13  connected to the connecting pin  24  in two positions is positioned in a surface parallel to the grounding surface G on the substrate  21  to which the bezel  13  is connected. The bezel  13  is paired with the grounding surface G and with this, operates as a micro-strip antenna. 
     As shown in  FIG.  3 B , the shield case  211  is provided on the bottom side of the substrate  21 , and the communicating circuit  213  regarding Bluetooth is positioned in the shield case  211 . 
     At least a portion of the frame  22  is a conducting member. The frame  22  stores, holds, and protects the battery  30  in a space inside. The frame  22  comes into contact with the grounding surface G of the substrate  21  and the back lid  17  (conducting portion) and spreads the range of the conducting surface to the back lid  17 . The frame  22  does not have to cover the entire side of the battery  30 , but the portions extending in the up and down direction include a plate shape or a pillar shape structure, and include a sufficiently large conducting surface area compared to wires on the substrate  21 . A plate spring  25  which is a conducting member (metal, etc.) may be positioned between the frame  22  and the back lid  17  and the frame  22  and the back lid  17  may be connected through the plate spring  25  so that the connection is more electrically stable and the resistance is low (low impedance). 
     The battery  30  is connected to an electric supply terminal of the substrate  21  and supplies electric power to the circuits of the substrate  21 . The battery  30  may be detachable and exchangeable or may be fixed to the frame  22 . In the latter situation, the battery  30  may be rechargeable by power generated by a solar panel (not shown) or the battery  30  may be connected to an external connecting terminal and the battery may be rechargeable by power supplied from outside. 
     As shown in  FIG.  3 B  and  FIG.  4   , an antenna element  214  is attached to the side of the frame  22 . As described above, the antenna element  214  is an antenna to transmit and receive a communicating radio wave when communication is performed by Bluetooth (here, monopole antenna bent in an S-shape), and the synchronizing frequency (receiving frequency) is different from the bezel  13 . The antenna element  214  transmits the receiving signal to the communicating circuit  213  on the substrate  21  through wires  2141 , and transmits the signal regarding the transmitted contents obtained from the communicating circuit  213 . The communicating circuit  213  may obtain the present date/time information from outside by Bluetooth. The controller may correct the date/time of the timekeeper based on the obtained date/time information. 
     The antenna element  214  is connected to the grounding terminal  215  on the back surface of the substrate  21  through wires  2142 . The grounding surface (not shown) including the grounding terminal  215  is connected to the conducting portion of the frame  22  in the nearby area (sufficiently short compared to the length of the monopole antenna such as within the range of the distance equal to or less than ½ of ¼ wavelength or equal to or less than ¼). As described above, the frame  22  is electrically connected to the back lid  17  through the plate spring  25 . The grounding surface G connected to the bezel  13  (connecting terminal  210 ) and the connecting surface connected to the antenna element  214  (grounding terminal  215 ) may be connected or may be separated from each other. 
     As described above, the antenna element  214  and the substrate  21  are positioned in the space inside the case  12  between the bezel  13  and the back lid  17 . According to such configuration, an electric field component projected on the grounding surface of the antenna element  214  which is the monopole antenna spreads mainly from the frame  22  to the back lid  17 . Therefore, the potential of the grounding surface G on the substrate  21  is not greatly disturbed from the grounding potential. With this, the grounding surface G on the substrate  21  by the bezel  13  functions suitably and the radio wave from the positioning satellite can be received with good sensitivity. 
     Among the above structures, the bezel  13 , the antenna element  214 , the substrate  21  including the satellite radio wave receiving module  212 , the communicating circuit, and the grounding surface G and the back lid  17  are included in the antenna receiving apparatus according to the present embodiment. 
     According to the present embodiment, the antenna receiving apparatus according to the present embodiment includes a bezel  13  as a first antenna, an antenna element  214  which synchronizes with a frequency band different from the bezel  13 , a substrate  21  including a receiving circuit (satellite radio wave receiving module  212  and communicating circuit  213 ) to which the bezel  13  and the antenna element  214  are connected, and a back lid  17  that includes a conductor, wherein the conductor is in at least a portion of the back lid. The substrate  21  includes a grounding surface G of the bezel  13 . The substrate  21  and the antenna element  214  are positioned between the bezel  13  and the back lid  17 . The antenna element  214  is positioned on the side of the substrate  21  opposite to the bezel  13 , and is electrically connected to the conducting portion of the back lid  17  and grounded. 
     As described above, by separating the grounding surface according to the operations of the plurality of antennas, the bad influence on another operation by one electric field pattern on the grounding surface caused in one operation can be reduced. By dividing the groups including the antenna and the grounding surface to the front surface side and the back surface side, the radio wave receiving accuracy of each group is not reduced. Therefore, communication operations by a plurality of antennas can be performed suitably in parallel in the antenna receiving apparatus. That is, according to JP 2019-124641, the monopole antenna and the path antenna which are stored in the case and often used when transmitting and receiving wireless radio waves such as those in the GHz band need a grounding surface. When the case grounding surface in the antenna receiving apparatus is a large range in the antenna receiving apparatus, if the operation of a plurality of antennas are performed together, the electric field pattern occurring on the grounding surface according to one antenna operation may have a bad influence on the reception of the radio wave by another antenna. According to the present embodiment, it is possible to perform the receiving operation by a plurality of antennas suitably in parallel. 
     Specifically, by performing the grounding to the back lid  17  of the antenna element  214  through the grounding surface of the substrate  21 , the difficulty of manufacturing can be decreased. In a portable antenna receiving apparatus, it is often assumed that a large impact is provided when carried, but it is difficult from limitations in the manufacturing process and structure to directly connect the antenna element  214  to the back lid  17  strongly to be prepared for impact. On the other hand, it is relatively easy to connect the grounding surface of the substrate  21  with a large size in the antenna apparatus to the back lid  17 . It is easily possible to make it difficult for the contact between the substrate  21  and the back lid  17  to become completely off even if a large impact is applied to the antenna receiving apparatus. Therefore, the antenna receiving apparatus in which the back lid  17  is grounded through the grounding surface of the substrate  21  can be easily manufactured, and it is possible to stably perform reception of radio waves in a plurality of frequencies in parallel. 
     The antenna element  214  is connected to the side of the substrate  21  opposite of the bezel  13 . The antenna element  214  positioned on the back side of the substrate  21  is directly connected to the back side of the substrate  21 . With this, the lines can be made easy and short, and the influence of parasitic resistance and parasitic capacitance in the middle can be reduced. 
     The antenna receiving apparatus (electronic watch  1 ) includes a frame  22  positioned between the substrate  21  and the back lid  17 . The antenna element  214  is electrically connected to the conductor portion of the back lid  17  through the frame  22 . The supporting member such as the frame  22  includes a width and thickness larger than the wires. Therefore, the frame  22  itself may also be the grounding surface. Therefore, it is possible to increase the grounding area near the antenna element  214 , and the portion which is to be the grounding surface of the antenna element  214  can be separated from the portion which is to be the grounding surface G of the bezel  13 . Therefore, suitable reception can be performed. 
     The frame  22  is storage including a space where the battery  30  is positioned inside. In a small portable device such as an electronic watch, the volume that the battery  30  occupies is large, and the frame  22  according to the above is also large. Therefore, it is possible to enlarge the grounding area by effectively using the conventional structure. Moreover, the frame  22  can be connected to the back lid  17  with low resistance, and the frame  22  hardly causes the reception sensitivity of the antenna element  214  to become low. 
     The bezel  13  is a ring shape and is positioned in a surface parallel to the substrate  21 . According to such position, when a display in the center, specifically a round display as in a wrist watch is included, it is possible to suitably perform wireless communication without interfering with the display. 
     The antenna element  214  is a monopole antenna. In the monopole antenna, since ¼ of a wavelength appears on the grounding surface as a reflected image, the influence of the grounding surface in a limited area is large. In this case, by separating the grounding surface from the substrate  21  to the back lid  17 , it is possible to reduce the influence of the bezel  13  to the radio wave reception. 
     The bezel  13  receives the radio wave from the positioning satellite, and the antenna element  214  receives the radio wave regarding the wireless radio wave communication by Bluetooth with external devices. The radio waves with two wavelengths often used in recent portable electronic devices can be suitably received at the same time. Therefore, the convenience of the portable electronic device may be enhanced. 
     The electronic watch  1  according to the present embodiment includes an antenna receiving apparatus, a time keeper which counts present time, and a controller which corrects the present time counted by the time keeper based on the radio wave received by at least the bezel  13  and/or the antenna element  214 . According to such electronic watch  1 , it is possible to transmit and receive the radio waves with two types of wavelengths in parallel without increasing the size of the watch. Therefore, the function of the electronic watch  1  can be enhanced. 
     The present invention is not limited to the above-described embodiments, and various modifications are possible. 
     For example, according to the present embodiment, the bezel  13  as the first antenna is described to be a ring shape to match with the structure of the electronic watch  1  but the shape is not limited to the above. If there is no problem in positioning, antennas with other shapes such as a plane antenna is possible. Alternatively, the antenna element  214  is described as the monopole antenna, but the antenna element  214  may function as the pair to the back lid and may be a patch antenna which receives the radio wave. Even if the device is the electronic watch, the first antenna does not have to be a bezel. 
     According to the above embodiment, the bezel  13  on the upper surface side of the substrate  21  receives the radio wave from the positioning satellite, and the antenna element  214  on the lower surface side of the substrate  21  is the antenna which performs communication by Bluetooth, but the combination is not limited to the above. The transmitting and receiving of other radio waves are possible as long as the antenna can be positioned in the suitable shape and the suitable relation in each position. For example, the antenna element  214  may transmit and receive the communication radio waves regarding wireless LAN. 
     The communicating circuit  213  connected to the antenna element  214  does not have to be positioned on the lower surface side of the substrate  21 . In this case, the lines  2141  may include a penetrating via or a through hole penetrating the substrate  21 . 
     The frame  22  according to the present embodiment does not have to be used to store the battery  30 . The frame  22  may support the substrate  21  or may store inside another structure such as a structure to drive the moveable portions such as the hands. The battery  30  may include various structures to obtain electric power by generating power by sunlight or oscillating in addition to the portion accumulating charge. 
     According to the present embodiment, the electronic watch  1  which is worn on the arm includes the antenna receiving apparatus, but the antenna receiving apparatus may be used in an electronic device other than a watch. For example, other electronic devices include an activity monitor or various measuring devices (sensors). Such electronic devices may include a timekeeping function. The electronic watch  1  may include various functions other than the timekeeping function. 
     Other than the above, the specific configuration, shape, structure, relation of positions, contents and procedures of the processes shown in the above embodiments can be suitably modified without leaving the scope of the present invention. 
     Although various embodiments have been shown and described, the scope of the present invention is not limited by the above-described embodiments, and the scope of the present invention includes the scope as described in the attached claims and its equivalents.