Antenna built-in type electronic watch

Abstract

To provide an antenna built-in type electronic watch equipped with a metal bezel and a flat-plate reverse-F type antenna and capable of suppressing deterioration of antenna performance.SOLUTION: The antenna built-in type electronic watch comprises: an antenna having a first conductor element, a second conductor element, and a short-circuit part; a time display unit disposed above the antenna; a cover glass disposed above the time display unit; a power supply unit that supplies power to the first conductor element; and a conductive case that has an annular wall and stores the antenna, the time display unit, and the power supply unit. The conductive case is provided with a support that projects inside from the side wall and supports the lower surface of the cover glass. In a side view, a distance from the lower surface of the support to the first conductor element is 0.012 or lower of a wavelength of a radio wave received through the antenna, and a distance from the cover glass to the first conductor element is 0.0238 or lower of the wavelength of the radio wave.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an electronic timepiece with a built-in antenna. [Background technology]

[0002] Patent Document 1 discloses that in an electronic watch with an internal antenna, the electronic watch has a case and bezel made of metal material, a cover crystal attached to the bezel, a base plate, a dial, and a planar inverted-F antenna positioned between the base plate and the dial, the distance between the dielectric cover crystal and the inverted-F antenna is set to 1 / 42 or less of the wavelength of the radio waves to be received in order to reduce the deviation between the resonant frequency and the radiation efficiency. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-47144 Summary of the Invention [Problem to be solved by the invention]

[0004] In a watch that uses a flat inverted F-shaped antenna, in order to use a metal bezel to improve the appearance, it is effective to keep the distance between the inverted F-shaped antenna and a dielectric such as a cover glass within a specified range, as in Patent Document 1. However, bringing the inverted-F antenna closer to the cover glass brings the glass support part of the metal bezel closer to the outer periphery of the antenna, creating a new problem of degradation in antenna performance. [Means for solving the problem]

[0005] The electronic timepiece with an internal antenna disclosed herein comprises an antenna having a flat first conductive element, a flat second conductive element that overlaps with the first conductive element in a planar view seen from a direction perpendicular to the surface of the first conductive element and is located below the first conductive element, and a short-circuiting portion that shorts the first conductive element and the second conductive element, a time display unit located above the antenna, a cover crystal located above the time display unit, a power supply unit that supplies power to the first conductive element, and a conductive case having an annular side wall that houses the antenna, the time display unit and the power supply unit, wherein the conductive case comprises a support portion that protrudes inward from the side wall and supports the underside of the cover crystal, and wherein, in a side view seen from a direction parallel to the surface of the first conductive element, the distance from the underside of the support portion to the first conductive element is 0.012 wavelengths or more of the wavelength of the radio waves received by the antenna, and the distance from the cover crystal to the first conductive element is 0.0238 wavelengths or less of the wavelength of the radio waves.

[0006] The electronic timepiece with an internal antenna of the present disclosure comprises an antenna having a flat first conductor element, a flat second conductor element that overlaps with the first conductor element in a planar view seen from a direction perpendicular to the surface of the first conductor element and is positioned below the first conductor element, and a short-circuiting portion that shorts the first conductor element and the second conductor element, a time display unit positioned above the antenna, a cover crystal positioned above the time display unit, a power supply unit that supplies power to the first conductor element, and a case that houses the antenna, the time display unit, and the power supply unit, wherein the case comprises a non-conductive body and a conductive bezel, the bezel comprises a support portion that supports the underside of the cover crystal, and wherein, in a side view seen from a direction parallel to the surface of the first conductor element, the distance from the underside of the support portion to the first conductor element is 0.012 wavelengths or more of the wavelength of the radio waves received by the antenna, and the distance from the cover crystal to the first conductor element is 0.0238 wavelengths or less of the wavelength of the radio waves. [Brief description of the drawings]

[0007] [Figure 1]FIG. 2 is an explanatory diagram showing an electronic timepiece and positioning information satellites according to the first embodiment. [Diagram 2] 1 is a front view showing an electronic timepiece according to a first embodiment. [Diagram 3] FIG. 2 is a cross-sectional view showing the electronic timepiece. [Figure 4] FIG. 2 is an exploded perspective view showing a main part of the electronic timepiece. [Diagram 5] FIG. 2 is a perspective view showing a main portion of the antenna of the electronic timepiece. [Figure 6] FIG. 2 is a perspective view showing a main portion of the antenna of the electronic timepiece. [Figure 7] FIG. 2 is a block diagram showing a circuit configuration of the electronic timepiece. [Figure 8] 1 is a graph showing the directivity of an antenna. [Figure 9] FIG. 4 is a diagram showing an electric field distribution of the antenna of the embodiment. [Figure 10] FIG. 4 is an enlarged cross-sectional view showing the positional relationship between the case and antenna of the electronic timepiece. [Figure 11] 13 is a graph showing the relationship between distance H1 and relative antenna gain. [Figure 12] 13 is a graph showing the relationship between distance W1 and relative antenna gain. [Figure 13] FIG. 11 is a cross-sectional view showing an electronic timepiece according to a second embodiment. [Figure 14] FIG. 11 is a bottom view showing the case of the second embodiment. [Figure 15] FIG. 11 is an explanatory diagram showing an electronic timepiece and positioning information satellites according to a third embodiment. [Figure 16] FIG. 11 is a cross-sectional view showing an electronic timepiece according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [First embodiment] A first embodiment of the electronic watch 1 with a built-in antenna will be described below with reference to the drawings. In this embodiment, the crystal 15 side of the electronic watch 1 will be described as the front side or upper side, and the back cover 14 side will be described as the back side or lower side. The electronic watch 1 of this embodiment has a built-in antenna 50, which will be described later, and is configured to receive satellite signals from multiple positioning information satellites S, such as GPS satellites and quasi-zenith satellites, that orbit the Earth in a predetermined orbit, as shown in Figure 1, to obtain satellite time information and correct the internal time information.

[0009] 2 and 3, the electronic watch 1 has a case 10 that houses the dial 2, hands 3, date wheel 5, movement 20, antenna 50, etc. The electronic watch 1 also has a crown 6 for external operation, and two buttons 7 and 8. The dial 2, hands 3, and date wheel 5 form the time display unit that displays the time on the electronic watch 1.

[0010] The dial 2 is formed in a disk shape using a non-conductive material. The dial 2 in this embodiment is made of polycarbonate resin with a relative dielectric constant of 3. A through hole 2A is formed in the center of the plane of the dial 2, and three coaxial pointer shafts 35, 36, and 37 are disposed in the through hole 2A. The hour hand 31 is attached to the shaft 35, the minute hand 32 is attached to the shaft 36, and the second hand 33 is attached to the shaft 37. The shafts 35, 36, and 37 and the hands 3 (hour hand 31, minute hand 32, and second hand 33) are made of conductive metal members. A rectangular date window 2B is provided at the 3 o'clock position of the dial 2. A date wheel 5 is disposed on the back side of the dial 2, and the date wheel 5 can be seen through the date window 2B. The hour hand 31, minute hand 32, second hand 33, and date wheel 5 are driven via a step motor and a wheel train, which will be described later.

[0011] In this embodiment, the direction perpendicular to the surface of the dial 2, i.e., the axial direction of the pointer shafts 35-37, is defined as the first direction, and the direction along the surface of the dial 2, i.e., the direction perpendicular to the first direction, is defined as the second direction. In this embodiment, a plan view means viewing the electronic timepiece 1 from the first direction, and a side view means viewing the electronic timepiece 1 from the second direction. Since the surface of the dial 2 is parallel to the surface of the first conductor element 52, a side view also means viewing from a direction parallel to the surface of the first conductor element 52, and a plan view also means viewing from a direction perpendicular to the surface of the first conductor element 52.

[0012] [Exterior structure of electronic watch] As shown in Fig. 3, the case 10 comprises a case body 11 and a back cover 14. The case body 11 comprises a cylindrical body 12 and a ring-shaped bezel 13 provided on the front side of the body 12. Note that in this embodiment, the body 12 and the back cover 14 are configured as separate bodies, but this is not limited thereto, and a one-piece case in which the body 12 and the back cover 14 are integrated may also be used. Also, in this embodiment, the body 12 and the bezel 13 are configured as separate bodies, but this is not limited thereto, and a structure in which the body 12 and the bezel 13 are integrated may also be used, which has the advantage of being inexpensive. The materials of case 12, bezel 13, and back cover 14 are metallic materials, i.e., conductive materials, such as stainless steel, titanium alloy, aluminum, brass, etc. Therefore, case 10 constitutes a conductive case, and case 12 and bezel 13, i.e., case body 11, constitute the annular side wall of the conductive case.

[0013] A cover glass 15 is attached to the bezel 13. The cover glass 15 is formed in a disk shape, and an upper surface 151 and a lower surface 152 are flat surfaces parallel to the second direction. The cover glass 15 is made of a transparent material such as mineral glass, sapphire glass, or organic glass. Mineral glass is glass made of silica (silicon dioxide: SiO2), sapphire glass is glass made of alumina (aluminum oxide: Al2O3), and organic glass is a synthetic resin material such as acrylic. The cover glass 15 of this embodiment is made of plate-shaped sapphire glass. Sapphire glass has a relative dielectric constant of about 9 to 11 and is formed using single crystal sapphire made of high-purity alumina. Sapphire glass is characterized by its high hardness, resistance to scratches, its very smooth processed surface, excellent light transmittance, and high visibility. The crystal diameter, or diameter of the cover crystal 15, is determined by the size of the electronic timepiece 1, and the thickness of the cover crystal 15 is determined by the relationship between the crystal diameter and waterproof performance. For example, if the electronic timepiece 1 is waterproof to 10 atmospheres, the thickness of the cover crystal 15 is approximately 1.5 mm, and if it is waterproof to 20 atmospheres, the thickness of the cover crystal 15 is approximately 2.6 to 2.8 mm. Since the electronic timepiece 1 of this embodiment is waterproof to 20 atmospheres, the thickness of the cover crystal 15 is 2.6 to 2.8 mm. Furthermore, the side surface 153 of the cover crystal 15 is a circumferential surface parallel to the first direction.

[0014] The bezel 13 includes a surface 131 , an opposing surface 132 , and a support piece 133 . On the surface 131 of the bezel 13, as shown in Fig. 2, time difference information indicating the time difference from Coordinated Universal Time (UTC) is written in numbers as decoration, and three-letter city information indicating the representative city name of the time zone that uses the standard time corresponding to the time difference of the time difference information is written alongside the time difference information. Here, the display of the time difference information and city information is called a time zone display. Since the time zone display is provided as decoration on the surface 131 of the bezel 13, the time zone display can also be indicated by the second hand 33 when checking the time zone, improving the design and convenience of the electronic watch 1. 3, the facing surface 132 is a surface along a first direction that is the axial direction of the pointer shafts 35 to 37, and is a circumferential surface along the inner circumferential surface of the bezel 13. This facing surface 132 faces a side surface 153 of the cover crystal 15, and holds the cover crystal 15 via a plastic packing 17. In this way, the cover crystal 15 is attached to the bezel 13, i.e., the case 10. The support piece 133 protrudes inward from the lower side of the opposing surface 132 and is formed in an annular shape around the entire circumference of the opposing surface 132. The support piece 133 abuts against a lower surface 152 of the cover glass 15 and supports the cover glass 15. Therefore, the support piece 133 is a support part that protrudes inward from the annular side wall of the conductive case and supports the lower surface 152 of the cover glass 15.

[0015] [Internal structure of an electronic clock] Next, the internal structure housed in the case 10 of the electronic timepiece 1 will be described. As shown in FIG. 3, in addition to the dial 2, a dial ring 16, a movement 20, etc. are housed within the case 10.

[0016] The dial ring 16 is made of a non-conductive material in the same ring shape as the dial 2, and is disposed along the outer periphery of the dial 2. The dial ring 16 in this embodiment is made of polycarbonate resin with a relative dielectric constant of 3. The dial ring 16 covers the outer periphery of the upper surface of the dial 2 , and the outer periphery of the dial 2 is hidden by the dial ring 16 .

[0017] 3 and 4, the movement 20 includes a date indicator 5, a main plate 21, a train wheel bridge 22, a drive mechanism 23, a secondary battery 24, a solar panel 25, an antenna 50, an LED board 60, a circuit board 65, a magnetic shield 81, a circuit holder 82, etc. Note that the train wheel bridge 22, the LED board 60, and the magnetic shield 81 are not shown in FIG.

[0018] The main plate 21 is made of a non-conductive material such as plastic. As shown in Fig. 3 and Fig. 4, the solar panel 25, the antenna 50, the date wheel 5, and the LED board 60 are arranged between the main plate 21 and the dial 2. That is, the solar panel 25 is arranged on the back side of the dial 2, which is the surface facing the main plate 21, the dielectric board 51 of the antenna 50 is arranged on the back side of the solar panel 25, the date wheel 5 and the LED board 60 are arranged on the back side of the dielectric board 51, and the second conductor element 53 of the antenna 50 is arranged on the back side of the date wheel 5 and the LED board 60. The second conductor element 53 serves both as an hour wheel holder and an antimagnetic plate, as described later. Between the main plate 21 and the back cover 14, there are arranged a wheel train bridge 22, a drive mechanism 23, a secondary battery 24, a circuit board 65, a magnetic shield 81, and a circuit holder 82.

[0019] 4, the train wheel bridge 22 includes two train wheel bridges: a first train wheel bridge 22A that supports a train wheel that drives the hour hand 31, minute hand 32, and second hand 33, and a second train wheel bridge 22B that supports a train wheel that drives the date indicator 5. However, it may be an integrated train wheel bridge.

[0020] The drive mechanism 23 is attached to the back surface of the main plate 21, and drives the hour hand 31, minute hand 32, second hand 33, and date wheel 5. That is, as shown in Fig. 4, the drive mechanism 23 has a first step motor 231 and a first wheel train that drive the hour hand 31, a second step motor 232 and a second wheel train that drive the minute hand 32, a third step motor 233 and a third wheel train that drive the second hand 33, and a fourth step motor 234 and a fourth wheel train that drive the date wheel 5. The first wheel train is provided with a pointer shaft 35 to which the hour hand 31 is attached. The second wheel train is provided with a pointer shaft 36 to which the minute hand 32 is attached. The third wheel train is provided with a pointer shaft 37 to which the second hand 33 is attached. In the movement 20, a winding stem 260 connected to the crown 6 is disposed at the 3 o'clock position of the dial 2, and a switching mechanism 261 such as a mandarin orange is disposed around the winding stem 260. In addition, the step motors 231 to 234 are disposed at positions that do not overlap with the secondary battery 24 in the plan view.

[0021] 4, the base plate 21 and the drive mechanism 23 are disposed between the LED board 60 and the circuit board 65. In addition, a magnetic shield 81 and a circuit holder 82 are disposed on the rear surface of the circuit board 65. On the back surface of the LED board 60 facing the base plate 21, three light emitting elements 611, 612, and 613 made of light emitting diodes are mounted, as shown in FIG. Circuit elements such as semiconductor integrated circuits (ICs: Integrated Circuits), resistors, capacitors, etc. are mounted on both the front and back sides of the circuit board 65. Furthermore, although not shown, three light receiving elements that receive light from light emitting elements 611, 612, and 613 are mounted on the front surface of the circuit board 65, i.e., the surface on the dial 2 side. These light emitting elements 611 to 613 and light receiving elements are used to detect the position of each pointer hand.

[0022] In this embodiment, a high-potential power supply voltage VDD and a low-potential power supply voltage VSS are supplied to the circuit board 65 via the secondary battery 24 and a constant voltage circuit (not shown). In this embodiment, the power supply voltage VDD is set to ground potential. Note that the power supply voltage VSS may also be set to ground potential. The LED board 60 and the circuit board 65 are electrically connected by conductive members 651, 652, 653, and 654, which are each formed of a coil spring, and thus power is supplied to the light emitting elements 611, 612, and 613.

[0023] The secondary battery 24 is a button-type lithium ion battery formed in a circular shape in plan view, and is disposed in a cutout portion of the circuit board 65 . Solar panel 25 is a solar cell panel used for wristwatches, and may be, for example, a film-type solar cell in which an amorphous silicon thin film is laminated on a resin film substrate. Solar panel 25 has through holes 25A through which pivots 35-37 are inserted, and two electrode terminals. These electrode terminals and circuit board 65 are electrically connected by coil springs 251, 252, as shown in FIG. 4. Therefore, the current generated by solar panel 25 is charged into secondary battery 24 via coil springs 251, 252 and circuit board 65.

[0024] [antenna] The antenna 50 is an antenna that receives satellite signals from GPS satellites, and in this embodiment, it is configured as a plate-shaped inverted F antenna. A typical plate-shaped inverted F antenna can obtain resonance characteristics with half the dimensions of a square patch antenna, making it possible to miniaturize the antenna, and is suitable as an antenna to be built into a small electronic watch 1 such as a wristwatch. However, the antenna directivity of an inverted F antenna is tilted obliquely from the zenith direction compared to a patch antenna, and when built into a watch, it is easily affected by the metal case and the antenna performance deteriorates significantly. In particular, in the first direction, which is the thickness direction of the watch, if the bezel located above the inverted F antenna, that is, on the cover crystal 15 side, is made of metal, it will affect the antenna performance, so a ceramic bezel was adopted. However, ceramic materials such as zirconia, which transmit radio waves, have color restrictions and low freedom, which limits the design of the watch. For this reason, the present inventors have thoroughly investigated a structure that can suppress deterioration of antenna performance even when a metal bezel 13 is used. As a result, they have found that when a metal bezel 13 is used, setting a predetermined distance between the support piece 133 that supports the cover crystal 15 and the antenna 50 is effective in reducing the influence of the metal bezel 13. The configuration of the antenna 50 and its positional relationship with the case 10 will be described below.

[0025] The antenna 50 is disposed so as to overlap the cover glass 15 in a planar view. As shown in Fig. 3 to Fig. 6, the antenna 50 is configured to include a dielectric substrate 51, a plate-shaped first conductor element 52, a second conductor element 53 disposed so as to overlap the first conductor element 52 in a planar view, and a short-circuit portion 54 which shorts the first conductor element 52 and the second conductor element 53. A through hole 50A through which the pointer shafts 35-37 are inserted is formed at the center position of the antenna 50 in the plan view. That is, the through hole 50A is formed penetrating the plate-shaped first conductive element 52, the dielectric substrate 51, and the second conductive element 53. Therefore, the planar shape of the antenna 50 is not affected by the positions of the pointer shafts 35-37, and it can be designed with a large area within the range that can be stored in the case 10, improving the reception performance. The antenna 50 also serves as a support substrate that supports the solar panel 25 made of a film.

[0026] The dielectric substrate 51 is a synthetic resin member that serves as an antenna substrate. If the material of the dielectric substrate 51 is any one of polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polycarbonate (PC), and syndiotactic polystyrene (SPS), it is easy to apply electroless plating and has a low dielectric tangent, making it suitable as an antenna substrate. A protrusion is formed on the back surface of the dielectric substrate 51, that is, the surface on the main plate 21 side. As shown in Fig. 4 and Fig. 6, the protrusion comprises an inner circumference side protrusion 51A formed on a position on the inner circumference side of the date indicator 5 in a plan view, and an outer circumference side protrusion 51B formed on a position on the outer circumference side of the date indicator 5. The dielectric substrate 51 has the function of pressing the date indicator 5 against the main plate. A recess 51C in which the LED substrate 60 is disposed is formed in the inner circumference side protrusion 51A.

[0027] The first conductor element 52 is formed on almost the entire surface of the dielectric substrate 51, that is, on the solar panel 25 side. The first conductor element 52 can be formed from a thin metal plate such as copper or an iron alloy, but in this embodiment, it is configured from a metal coating formed on the surface of the dielectric substrate 51. The metal coating can be formed by plating, for example, copper, silver, nickel, aluminum, or the like. The second conductor element 53 can be formed of a metal coating like the first conductor element 52, but in this embodiment, it is made of a magnetically resistant plate that also serves as a wheel retainer. The magnetically resistant plate constituting the second conductor element 53 is a conductor plate made of pure iron plate coated with a nickel film, and comes into contact with the short circuit portion 54 as described later. The first conductor element 52 functions as a radiating member of the plate-shaped inverted-F antenna, and the second conductor element 53 functions as a ground member of the plate-shaped inverted-F antenna.

[0028] As shown in FIG. 6, the short-circuit portion 54 is composed of a side short-circuit portion 54A formed on a side surface of the dielectric substrate 51, and a back surface short-circuit portion 54B formed on the back surface of the dielectric substrate 51, specifically, on the bottom surface of the outer circumferential protrusion portion 51B. A power supply terminal 55 is formed on the outer circumferential protrusion 51B, spaced apart from the short circuit portion 54. The power supply terminal 55 is electrically connected to the first conductive element 52 via the side surface of the dielectric substrate 51. As shown in Figs. 3 and 4, one end of the feeding element 56 abuts against the feeding terminal 55. The other end of the feeding element 56 abuts against the circuit board 65 and is electrically connected to the receiving IC mounted on the circuit board 65. In Fig. 3, the feeding element 56 is illustrated as penetrating the second conductive element 53 and the dielectric substrate 51 and contacting the first conductive element 52. In reality, however, as shown in Figs. 4 to 6, the feeding terminal 55 of the first conductive element 52 is extended to the lower surface through the side surface of the dielectric substrate 51, and the upper end of the feeding element 56 is in contact with the feeding terminal 55. The feeding element 56 is a pin-shaped connector made of a conductive material such as metal, and includes a coil spring. The feeding element 56 is in contact with the lower surface of the feeding terminal 55 by the biasing force of the coil spring. Therefore, the feeding section to which the first conductive element 52 is connected is configured to include the feeding terminal 55 and the feeding element 56.

[0029] The back surface short circuit portion 54B laminated on the bottom surface of the outer circumferential protrusion 51B contacts the surface of the metallic second conductive element 53. The second conductive element 53 is electrically connected to the ground terminal of the circuit board 65 via the connection element 57, and functions as the ground member of the plate-shaped inverted F-shaped antenna. In addition, since the second conductive element 53 is made of metal, it also serves as a magnetic shield that covers the dial 2 side of the step motors 231-234.

[0030] In this embodiment, when the antenna 50 is incorporated into the case body 11, a short-circuit portion 54 is provided at the 12 o'clock direction with respect to the through hole 2A of the dial 2 in a plan view. Therefore, in the first conductive element 52 that serves as the antenna electrode, the side opposite the short-circuit portion 54, that is, the 6 o'clock direction with respect to the through hole 2A of the dial 2 in a plan view, is defined as an open end 58 of the antenna 50.

[0031] [Circuit configuration of electronic clock] FIG. 7 is a block diagram showing the circuit configuration of the electronic watch 1. The electronic watch 1 has a GPS receiving unit 300 , a control display unit 400 , and a power supply unit 500 , all of which are arranged on a circuit board 65 .

[0032] [GPS receiver] The GPS receiving unit 300 receives and processes satellite signals from GPS satellites via the antenna 50 and the SAW filter 230. The SAW filter 230 is a band-pass filter that passes 1.5 GHz satellite signals. Note that an LNA that improves reception sensitivity may be separately inserted between the antenna 50 and the SAW filter 230. Also, the SAW filter 230 may be built into the GPS receiving unit 300. Note that SAW is an abbreviation for Surface Acoustic Wave, and LNA is an abbreviation for Low Noise Amplifier.

[0033] The GPS receiver 300 processes the satellite signal that has passed through the SAW filter 230, and includes an RF circuit 310, a baseband circuit 320, a crystal oscillator circuit 330 with a temperature compensation circuit, and a flash memory 340. Note that RF is an abbreviation for Radio Frequency. Also, the crystal oscillator circuit 330 with a temperature compensation circuit is abbreviated as TCXO in FIG. 7.

[0034] The RF circuit 310 is a typical RF section for GPS reception that includes a PLL, VCO, LNA, mixer, IF amplifier, IF filter, A / D converter, etc. Note that PLL is an abbreviation for Phase Locked Loop, VCO is an abbreviation for Voltage Controlled Oscillator, and IF is an abbreviation for Intermediate Frequency.

[0035] The baseband circuit 320 is a typical baseband unit for GPS reception that includes a DSP, CPU, RTC, SRAM, etc. The baseband circuit 320 is also connected to a TCXO 330 and a flash memory 340. Note that DSP is an abbreviation for Digital Signal Processor, CPU is an abbreviation for Central Processing Unit, RTC is an abbreviation for Real Time clock, and SRAM is an abbreviation for Static Random Access Memory.

[0036] The baseband circuit 320 receives the digitally converted received signal from the RF circuit 310, and performs correlation processing, positioning calculations, etc. to obtain satellite time information and positioning data. It then uses the leap seconds stored in the SRAM to correct the obtained satellite time information, i.e., the Z count, and calculates UTC, which is the time data. The baseband circuit 320 then outputs the positioning data and time data to the control unit 410 of the control display unit 400. The clock that is the basis of the local oscillation signal is supplied from the TCXO 330 to the RF circuit 310 via the baseband circuit 320 .

[0037] A time difference database in which location information specified by latitude and longitude is associated with time difference information for that location is stored in flash memory 340. When GPS receiver 300 acquires location information in positioning mode, it acquires time difference information, that is, the time difference from UTC, based on the location information (latitude, longitude) and outputs it to control unit 410.

[0038] [Control display section] The control display unit 400 includes a control unit (CPU) 410, a drive circuit 420 that drives the hands and the like, and a crystal oscillator 430.

[0039] The control unit 410 includes an RTC 411, a ROM 412, and a storage unit 413, and keeps time, and outputs a control signal to the GPS receiving unit 300 to control its operation. The RTC 411 keeps internal time using a reference signal output from the crystal oscillator 430. Various programs executed by the control unit 410 are stored in the ROM 412. In this embodiment, the internal time kept by the RTC 411 is UTC, which is Universal Coordinated Time. If reception in the timekeeping mode or positioning mode is successful, the control unit 410 updates the RTC 411 with the UTC output from the GPS receiving unit 300. The memory unit 413 stores the satellite time information, positioning information, and time difference information output from the GPS receiving unit 300. For this reason, the control unit 410 calculates the time at the current location using UTC and the time difference information, and drives the drive mechanism 23 using the drive circuit 420 to indicate the calculated time with the hour hand 31, minute hand 32, and second hand 33.

[0040] [Power supply section] The power supply unit 500 supplies power to the GPS receiving unit 300 and the control display unit 400, and includes a solar panel 25, a charge control circuit 510, a secondary battery 24, a first voltage conversion unit 520, a second voltage conversion unit 530, and a voltage detection circuit 540. The charging control circuit 510 controls the charging of the secondary battery 24 with the power generated by the solar panel 25 . The secondary battery 24 supplies driving power to the control display unit 400 via the first voltage conversion unit 520 , and supplies driving power to the GPS receiving unit 300 via the second voltage conversion unit 530 . The voltage detection circuit 540 monitors the output voltage of the secondary battery 24 and outputs it to the control unit 410. Therefore, the control unit 410 can grasp the voltage of the secondary battery 24 detected by the voltage detection circuit 540 and control the reception process.

[0041] [Antenna characteristics] In order to receive satellite signals from GPS satellites that are right-handed polarized, the antenna 50 has a short-circuiting portion 54 at 12 o'clock to improve reception sensitivity. That is, the directivity of the right-handed polarized waves of the antenna 50, which is an inverted F-shaped antenna, is tilted from the zenith direction perpendicular to the first conductive element 52, which is the upper antenna plate, that is, from the 0 degree direction in FIG. 8. Specifically, the directivity of the right-handed polarized waves of the antenna 50 is tilted about 60 degrees to the right from the direction perpendicular to the first conductive element 52, which is the upper antenna plate, in a side view of the antenna 50 seen from the short-circuiting portion 54 side. For this reason, it is preferable to store the antenna 50 in the case 10 so that the short-circuiting portion 54 of the antenna 50 is at the 12 o'clock direction of the electronic timepiece 1. When the short-circuiting portion 54 is positioned in this way, the directivity is tilted about 60 degrees toward the 9 o'clock direction with respect to the direction perpendicular to the dial 2. When the electronic timepiece 1 is worn on the left wrist and the arm is naturally lowered while walking, the 9 o'clock side of the electronic timepiece 1 faces vertically upward. As a result, when receiving right-hand circularly polarized (RHCP) radio waves from a GPS satellite, the directivity of the antenna 50 roughly coincides with the 9 o'clock direction, which is the vertically upward direction of the electronic watch 1, making it possible to receive satellite signals efficiently.

[0042] Also, as shown in Fig. 9, the antenna 50 radiates most of the radio waves from the open end 58 side, which is the opposite side of the short circuit portion 54, i.e., the 6 o'clock side of the electronic timepiece 1. For this reason, the most effective way to reduce the influence of the case 10 is to separate the open end 58 of the antenna 50 from the metal case 10. Note that, as shown in Fig. 9, on the inner circumferential surface 101 of the case 10, the part that affects reception of the antenna 50 is from the underside of the support piece 133 to the height position facing the second conductive element 53, which is the underside electrode of the antenna 50, so it is preferable to position the open end 58 of the antenna 50 away from the case 10 within this range.

[0043] [Positional relationship between antenna and case] Next, the positional relationship between the antenna 50 and the case 10 will be described with reference to FIG. 10, in a side view, the distance from the lower surface of the support piece 133 supporting the lower surface 152 of the cover glass 15 to the surface of the first conductor element 52 is defined as H1, and the distance from the lower surface 152 of the cover glass 15 to the surface of the first conductor element 52 is defined as H2. In addition, in a plan view, the distance between the inner peripheral surface 101 of the case 10 and the outer peripheral surface 52B of the first conductor element 52 is defined as W1, and the distance between the inner peripheral surface 133A of the support piece 133 and the outer peripheral surface 52B of the first conductor element 52 is defined as W2. Note that the distances H1 and H2 are length dimensions along the first direction, and the distances W1 and W2 are dimensions along the second direction.

[0044] [Setting distance H1] 11 shows the results of a simulation that determined the relationship between distance H1 and antenna gain when distance W1 was set to 1.75 mm. In the simulation, the thickness of the electronic timepiece 1, specifically the distance between the back cover 14 and the crystal 15, was fixed, and distance H1 was varied by changing the thickness of the support piece 133. As shown in Fig. 11, when the lower surface of the support piece 133 is brought closer to the antenna 50 and the distance H1 is reduced, the deterioration of the antenna gain increases. In the graph of Fig. 11, the horizontal axis represents the distance H1, and the vertical axis represents the relative antenna gain. The distance H1 is displayed as a ratio to the wavelength of the radio wave received by the antenna 50. The antenna 50 receives radio waves with a frequency of 1.575 GHz transmitted from a GPS satellite, which is a positioning information satellite S, that is, radio waves with a wavelength of approximately 190 mm, so that the distance H1 of 0.012 wavelengths is 190 x 0.012 = 2.28 mm. Note that the wavelength of the radio wave is the wavelength in free space, and is not the wavelength shortened by a dielectric material. The relative antenna gain, which is the vertical axis of Fig. 11, is the antenna gain for the distance H1, expressed as a relative value of the antenna gain change amount with reference to the case where H1 = 3.3 mm (approximately 0.0174 wavelengths). Here, the allowable value of antenna gain degradation is about 0.5 dB. Therefore, it is preferable that the distance H1 is 0.012 wavelengths (2.28 mm) or more, at which the relative antenna gain is -0.5 dB or less. In particular, it is more preferable to set the distance H1 to 0.014 wavelengths or more, since the amount of degradation of the antenna gain is small.

[0045] If the distance H1 is too large, the antenna 50 will be located deep inside the metal bezel 13 or the case 12. This will increase the height of the metal bezel 13, and satellite signals entering the surface of the antenna 50 from an oblique direction will be blocked by the bezel 13, making reception difficult. For this reason, the upper limit of the distance H1 is preferably about 0.02 wavelengths (3.8 mm) or less. Note that there is a restriction on the distance H2 described below, and furthermore, the thickness of the support piece 133 that supports the cover glass 15 needs to be a predetermined dimension in order to ensure the strength of the support piece 133, so that the distance H1 is usually set to 0.02 wavelengths or less. Note that the thickness of the support piece 133 is H2-H1, and is, for example, about 0.6 to 1.0 mm.

[0046] [Setting distance H2] The dielectric that contributes to reducing the frequency of the satellite signal received by the antenna 50, which is an inverted F-shaped antenna, is a dielectric that is arranged within a predetermined distance from the antenna 50, which is set according to the wavelength of the received radio wave. The predetermined distance between the dielectric arranged on the upper side of the antenna 50, i.e., the cover glass 15 side, and the antenna 50 is the distance H2 between the upper surface of the antenna 50, i.e., the upper surface of the first conductive element 52, and the lower surface of the cover glass 15, which is a dielectric. This distance H2 may be set to 1 / 42 or less of the wavelength of the received radio wave, as described in JP 2021-47144 A. Since 1 / 42 wavelength is approximately 0.0238 wavelength, the distance H2 may be set to 190 × 0.0238 = 4.522 mm or less.

[0047] [Setting distance W1] 12 is a graph with the horizontal axis representing distance W1 expressed in wavelength and the vertical axis representing relative antenna gain, and shows the results of a simulation in which distance H1 was set to 2.6 mm and distance W1 between the inner peripheral surface of metal case 10 and the outer peripheral surface of antenna 50 was changed. Note that distance W1 was changed by changing the thickness of case 10 without changing the outer diameter of case 10. As shown in FIG. 12, when the inner peripheral surface of the metal case 10 is brought closer to the antenna 50 to reduce the distance W1, the deterioration of the antenna gain increases. The relative antenna gain, which is the vertical axis of Fig. 12, is the antenna gain for the distance W1, and is expressed as a relative value of the antenna gain change amount with respect to the case where W1 = 2.5 mm (approximately 0.0131 wavelengths) as a reference. Here, the allowable value of antenna gain degradation is about 0.5 dB. Therefore, it is preferable that the distance W1 is 0.008 wavelengths (1.52 mm) or more, at which the relative antenna gain is -0.5 dB or less. In particular, it is more preferable to set the distance W1 to 0.0105 wavelengths (1.995 mm) or more, since the amount of degradation of the antenna gain is small. In addition, in FIG. 12 as well, the wavelength of the radio wave is the wavelength in free space, and is not a wavelength shortened by a dielectric. As described above in FIG. 9, in the planar direction, the area in which case 10 affects the receiving sensitivity of antenna 50 is from support piece 133 of cover glass 15 to the underside of antenna 50, and therefore, in this range, the outer peripheral surface of antenna 50 and the inner peripheral surface of case 10 are configured to be separated by a distance W1 or more.

[0048] The distance W2 may be 0 mm or more. That is, in a plan view, the inner peripheral surface 133A of the support piece 133 may be located outside the outer peripheral surface 52B of the first conductive element 52. This reduces radio waves blocked by the support piece 133, improving the reception performance of the antenna 50.

[0049] [Effects of the first embodiment] In the electronic timepiece 1 of the first embodiment, the distance H1 from the underside of the support piece 133 that supports the underside 152 of the crystal 15 to the first conductive element 52, which is the upper surface of the antenna 50, in a side view is set to be 0.012 or more wavelengths of the radio waves received by the antenna 50, which makes it possible to suppress deterioration of antenna performance and maintain the reception performance of radio waves such as satellite signals. This makes it possible to use a metal bezel 13 and case 12, which improves the external design of the electronic timepiece 1 while also ensuring the necessary antenna performance. Furthermore, the distance H2 from the cover glass 15 to the first conductive element 52 is set to 0.0238 wavelengths of the radio wave or less, so that the cover glass 15 can function as a dielectric. Therefore, the cover glass 15 can be placed within a predetermined distance set according to the wavelength of the radio wave received by the antenna 50, specifically, within a distance of 1 / 42 of the wavelength λ or less, and the wavelength shortening effect of the cover glass 15, which is a dielectric, can suppress the deviation between the resonance frequency of the antenna 50 and the frequency at which the radiation efficiency is optimal. This makes it possible to suppress the deterioration of the antenna gain, i.e., the reception performance, even if the bezel 13 is made of a conductive material such as stainless steel or titanium. Therefore, by using a metal bezel 13, the design of the case 10 can be improved, and by using an inverted F-shaped antenna 50, which can be made thinner than a patch antenna, the electronic watch 1 can also be made thinner while ensuring the reception performance of the antenna 50. Furthermore, by using a thin antenna 50, the secondary battery 24, step motors 231-234, wheel train, and other timepiece parts can be arranged overlapping the antenna 50 in a plan view. This allows the electronic timepiece 1 to be made more compact, that is, the planar size of the electronic timepiece 1 can be reduced.

[0050] [Second embodiment] An electronic timepiece 1B of the second embodiment will be described with reference to Figures 13 and 14. In the electronic timepiece 1B, the same components as in the first embodiment are given the same reference numerals and descriptions thereof will be omitted. The case 10B of the electronic timepiece 1B includes a body 12B and a bezel 13. A recess 121 is formed on the inner surface of the body 12B in the range from the 3 o'clock position through the 6 o'clock position to the 9 o'clock position, and the inner diameter of the inner surface 101B is made larger than the 12 o'clock side. In other words, the recess 121 is formed so that the amount of recession toward the outer periphery of the body 12B is smallest at the 3 o'clock and 9 o'clock positions on the inner surface of the body 12B and gradually increases toward the 6 o'clock position. 13, the distance W1 between the inner circumferential surface 101B and the outer circumferential surface of the antenna 50 is greatest at the 6 o'clock position. In other words, the distance between the inner circumferential surface 101B and the outer circumferential surface on the open end side of the antenna 50 is greater than the distance between the inner circumferential surface 101B and the outer circumferential surface on the short-circuit portion 54 side of the antenna 50. Although not shown, the distance H1 from the lower surface of the support piece 133 to the first conductive element 52 and the distance H2 from the lower surface 152 of the cover glass 15 to the first conductive element 52 are the same as in the first embodiment.

[0051] The second embodiment can achieve the same effects as the first embodiment. In addition, a recess 121 is formed in the inner peripheral surface 101B of the body 12B, and the distance W1 between the outer peripheral surface of the antenna 50 and the inner peripheral surface 101B is set to be largest in the 6 o'clock direction, that is, on the open end side of the antenna 50. This can further reduce the influence of the metal body 12B and improve the reception performance of the antenna 50. In addition, since open end 58, which emits more radio waves than short-circuit portion 54 of antenna 50, is separated from inner surface 101B of case 10B, the necessary antenna performance can be ensured and restrictions on the structure and dimensions of short-circuit portion 54 are reduced, improving the design freedom of antenna 50 and case 10B.

[0052] [Third embodiment] An electronic timepiece 1C of a third embodiment will be described with reference to Fig. 15 and Fig. 16. The electronic timepiece 1C is a sports watch suitable for multiple sports such as running and trekking, and is a GPS watch equipped with an antenna 90 that receives a satellite positioning system, for example a GPS satellite signal as a global navigation satellite system. Like the antenna 50, the antenna 90 is an antenna that utilizes a plate inverted F antenna (PIFA (Plate Inverted F Antenna) or Planar Inverted F Antenna)).

[0053] As shown in FIG. 15, the electronic timepiece 1C includes a case 10C with a bezel 13C, a digital display panel 70 as a time display section, and buttons 201. The electronic timepiece 1C is capable of receiving satellite signals from a positioning information satellite S. As shown in FIG. 16, the digital display panel 70 is specifically configured with a liquid crystal display 70A. The electronic timepiece 1C has a case 10C. The case 10C is equipped with a case 12C and back cover 14C made of synthetic resin, and a bezel 13C made of conductive metal. As with the previous embodiments, the bezel 13C is equipped with a support piece 133C that supports the crystal 15. Inside the case 10C, there are arranged a liquid crystal display 70A constituting the digital display panel 70, a partition plate 72, a frame 77 for holding the liquid crystal display 70A, a circuit board 45, an antenna 90, an acceleration sensor 94, a secondary battery 24, a vibration unit 95, etc.

[0054] The frame 77 has a wall 73 on its outer periphery, opens towards the cover glass 15, and includes a recess 74 having an inner bottom surface 74b on the inside of the wall 73. The inner bottom surface 74b of the recess 74 is provided with a through hole 76 penetrating the front and back of the central portion of the inner bottom surface 74b. The frame 77 has a liquid crystal display 70A attached to the inner bottom surface 74b located on the outer periphery side of the through hole 76 of the recess 74 via a peripheral seal member 79. The wall 73 of the frame 77 and the boundary between the wall 73 and the liquid crystal display 70A are covered and hidden by a partition plate 72. The liquid crystal display 70A is electrically connected to a circuit board 45 via a flexible connection board 46 and the like, and is controlled by a drive circuit provided on the circuit board 45. Although the digital display panel 70 is configured by the liquid crystal display 70A in the above example, the present invention is not limited to this. The digital display panel 70 can be configured by a liquid crystal display (LCD), an organic EL (Organic ElectroLuminescence) display, an EPD (Electrophoretic Display), or the like.

[0055] The antenna 90 includes a resin frame 80, a first conductor element 91, a second conductor element 92, and a short circuit portion 93. The first conductor element 91 is a plate-shaped conductor element that serves as an antenna electrode. The second conductor element 92 is configured by a grounding pattern (GND layer) included in a wiring pattern disposed on one surface of the circuit board 45. The short circuit portion 93 is led out from the outer edge portion of the first conductor element 91, and electrically connects the first conductor element 91 and the second conductor element 92. A circuit case 44 that guides the secondary battery 24 and the like is disposed on the surface of the circuit board 45 facing the back cover 14C. The resin frame 80 is constructed in a skeletal form with a number of blocks connected by beams, and is configured so that the frequency of the received radio waves can be adjusted by cutting appropriate beams, for example. The antenna 90 is a plate-like inverted F-shaped antenna, similar to the antenna 50 of the first embodiment, in which a plate-like first conductor element 91 and a circuit board 45 as a plate-like element including a second conductor element 92 are arranged to face each other with a resin frame 80 in between, and the first conductor element 91 and the second conductor element 92 are short-circuited using a short-circuiting portion 93, and power is fed to the first conductor element 91 by a power feeding element (not shown) to obtain radio wave radiation. The resin frame 80 is arranged between the circuit board 45 and the first conductor element 91, thereby achieving the effect of maintaining the parallelism between the second conductor element 92 and the first conductor element 91, and also contributing to the electrical performance of the antenna 90, which is a GPS antenna.

[0056] At least a part of the outer edge region of the first conductive element 91 extends beyond the liquid crystal display 70A that constitutes the digital display panel 70 in a plan view of the electronic timepiece 1C seen from the crystal 15 side. This makes it possible to maintain antenna performance even if the liquid crystal display 70A and the antenna 90 overlap. Furthermore, as in the first embodiment, the distance H1 from the underside of the support piece 133C to the surface of the first conductor element 91 of the antenna 90 is 0.012 wavelengths or more of the radio waves received by the antenna 90, the distance H2 from the underside of the cover glass 15 to the surface of the first conductor element 91 is 0.0238 wavelengths or less of the radio waves, and the distance W1 from the outer periphery of the first conductor element 91 to the inner surface of the metal bezel 13C is 0.008 wavelengths or more of the radio waves.

[0057] The third embodiment can achieve the same effects as the previous embodiments. That is, as in the previous embodiments, the distance H1 from the support piece 133C of the bezel 13C to the first conductive element 91 of the antenna 90 is set to 0.012 or more wavelengths of the satellite signal, which is the received radio wave, so that the decrease in reception sensitivity caused by the metal bezel 13C can be suppressed. This allows the metal bezel 13C that supports the crystal 15 to be relatively large, and the area covering the surface of the synthetic resin case 12C can also be increased, resulting in excellent scratch resistance and durability, and an enhanced luxurious appearance of the electronic timepiece 1C. Furthermore, since the antenna 90 can also receive radio waves that pass through the body 12C made of synthetic resin, the reception performance can be improved compared to when a metal body is used.

[0058] [Other embodiments] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the present invention. In the first embodiment, the second conductor element 53 of the antenna 50 was made of a magnetically-resistant plate, but the second conductor element 53 may be formed in a plate shape with approximately the same area as the first conductor element 52 and function as a ground member of the plate-shaped inverted-F antenna. In plan view, the inner peripheral surface of the support piece 133, 133C may be located at the same position as the outer peripheral surface of the first conductive element 52, 91 of the antenna 50, 90, or may be located further inward. That is, since the distance H1 is secured, the necessary reception performance can be maintained even if the inner peripheral surface of the support piece 133, 133C overlaps part of the first conductive element 52, 91 in plan view. A digital display panel 70 may be incorporated as a time display unit into the cases 10 and 10B of the first and second embodiments to display the time digitally. Also, a dial 2 and hands 3 may be incorporated into the case 10C of the third embodiment to display the time in analog form. In the above-described embodiments, the satellite signal transmitted from the GPS satellite is received to obtain the time information, but other signals may be received. For example, to obtain the time information, satellite signals transmitted from other global navigation satellite systems (GNSS) such as Galileo, GLONASS, and Beidou, satellite-based augmentation systems (SBAS), and regional positioning satellite systems (RNSS) that can be searched only in a specific region such as quasi-zenith satellites may be received. The antenna is not limited to one that receives satellite signals, and may be an antenna that receives other radio waves, such as Bluetooth (registered trademark), BLE (Bluetooth Low Energy), Wi-Fi (registered trademark), NFC (Near Field Communication), LPWA (Low Power Wide Area), etc. In other words, the antennas 50, 90 incorporated in the electronic watches 1, 1B, 1C may be appropriately set according to the type of radio waves to be received, the size of the watch, how it fits in with other components, etc.

[0059] [Summary of this disclosure] The electronic timepiece with an internal antenna disclosed herein comprises an antenna having a flat first conductor element, a flat second conductor element that overlaps with the first conductor element in a planar view seen from a direction perpendicular to the surface of the first conductor element and is located below the first conductor element, and a short-circuiting portion that shorts the first conductor element and the second conductor element, a time display unit located above the antenna, a cover crystal located above the time display unit, a power supply unit that supplies power to the first conductor element, and a conductive case having an annular side wall that houses the antenna, the time display unit, and the power supply unit, the conductive case comprising a support portion that protrudes inward from the side wall and supports the underside of the cover crystal, and in a side view seen from a direction parallel to the surface of the first conductor element, the distance from the underside of the support portion to the first conductor element is 0.012 wavelengths or more of the wavelength of the radio waves received by the antenna, and the distance from the cover crystal to the first conductor element is 0.0238 wavelengths or less of the wavelength of the radio waves. In the electronic timepiece with an internal antenna disclosed herein, the distance from the underside of the support part that supports the underside of the cover crystal to the first conductive element, which is the upper surface of the antenna, in a side view is set to 0.012 or more wavelengths of the radio waves received by the antenna, which prevents deterioration of antenna performance due to the support part made of a conductive material such as metal, and maintains the reception performance of radio waves such as satellite signals. Also, because a conductive case with an annular side wall can be used, even if a bezel with a support part that supports the cover crystal is provided, the bezel can be made of a conductive material such as metal, improving the external design of the timepiece. The distance from the cover glass to the first conductive element is set to 0.0238 wavelengths of radio waves or less, allowing the cover glass to function as a dielectric. Therefore, the wavelength shortening effect of the cover glass, which is a dielectric, can suppress the deviation between the antenna's resonant frequency and the frequency at which radiation efficiency is optimal. This makes it possible to suppress the deterioration of antenna gain, i.e., reception performance, even if the bezel is made of a conductive material. Therefore, by using a metal bezel, the design of the watch case can be improved, and by using a plate-shaped inverted-F antenna, which can be made thinner than a patch antenna, the electronic watch can also be made thinner while ensuring the reception performance of the plate-shaped inverted-F antenna. Furthermore, the battery, motor, wheel train, and other watch components can be arranged overlapping the inverted-F antenna in a planar view, making it possible to miniaturize the electronic watch, i.e., reduce the planar size of the electronic watch.

[0060] In the electronic timepiece with an internal antenna disclosed herein, it is preferable that the distance from the underside of the support part to the first conductive element in the side view is greater than or equal to 0.014 wavelengths of the radio waves received by the antenna. In the electronic watch with built-in antenna disclosed herein, the distance to the first conductive element, which is the top surface of the antenna, is set to be 0.014 or more wavelengths of the radio waves received by the antenna, thereby further suppressing deterioration of antenna performance and further maintaining reception performance of radio waves such as satellite signals.

[0061] In the electronic timepiece with an internal antenna of this disclosure, it is preferable that, in the plan view, the inner circumferential surface of the support portion is positioned outside the first conductive element. In the electronic watch with built-in antenna disclosed herein, the inner surface of the support part that supports the cover crystal is positioned outside the first conductive element in a plan view, so that less radio waves are blocked by the support part, improving the reception performance of the antenna.

[0062] In the electronic watch with built-in antenna disclosed herein, it is preferable that, when viewed from the side, in the range from the underside of the support part to the underside of the second conductive element, the distance from the inner surface of the side wall of the conductive case to the outer surface of the first conductive element is greater than or equal to 0.008 wavelengths of the radio waves received by the antenna. According to the electronic watch with built-in antenna disclosed herein, by devising a shape for the inner circumference of the case that does not affect the external design of the watch, the distance from the antenna can be kept appropriate, thereby ensuring the necessary antenna performance while enhancing the appearance of the watch.

[0063] In the electronic watch with built-in antenna disclosed herein, it is preferable that the distance from the outer surface of the first conductive element on the opposite side of the short-circuit portion to the inner surface of the side wall of the conductive case is greater than the distance from the outer surface of the first conductive element at the short-circuit portion to the inner surface of the side wall of the conductive case. In the electronic watch with built-in antenna disclosed herein, the open end opposite the short-circuited part of the antenna, which emits more radio waves than the short-circuited part, is separated from the inner peripheral surface of the side wall of the conductive case, ensuring the necessary antenna performance. Also, since there are fewer restrictions on the structure and dimensions of the short-circuited part, there is more freedom in the design of the antenna and conductive case.

[0064] In the electronic timepiece with built-in antenna disclosed herein, the time display unit preferably includes a dial and hands, and the antenna preferably has a through hole through which the hand axis passes. The electronic timepiece with built-in antenna of the present disclosure can realize an analog timepiece that indicates the time with hands. In addition, because the antenna has a through hole through which the hand axis passes, the planar shape of the antenna is not affected by the position of the hand axis, and it can be designed with a large area within the range that can be housed in the conductive case, improving reception performance.

[0065] In the electronic timepiece with built-in antenna of the present disclosure, it is preferable that the time display unit is a digital display panel. The electronic timepiece with built-in antenna of the present disclosure makes it possible to realize a digital timepiece that displays the time on a digital display panel such as a liquid crystal panel or an organic EL panel.

[0066] In the electronic watch with built-in antenna disclosed herein, the conductive case preferably comprises a conductive bezel having the support portion, and a conductive body that houses the antenna, the time display portion, and the power supply portion, and the surface of the bezel is preferably decorated. The electronic watch with built-in antenna disclosed herein uses a metal bezel and case, and the surface of the bezel is further decorated with, for example, numbers and letters to display the time zone, thereby improving the design and convenience of the electronic watch.

[0067] The electronic timepiece with an internal antenna of the present disclosure comprises an antenna having a flat first conductor element, a flat second conductor element that overlaps with the first conductor element in a planar view seen from a direction perpendicular to the surface of the first conductor element and is positioned below the first conductor element, and a short-circuiting portion that shorts the first conductor element and the second conductor element, a time display unit positioned above the antenna, a cover crystal positioned above the time display unit, a power supply unit that supplies power to the first conductor element, and a case that houses the antenna, the time display unit, and the power supply unit, wherein the case comprises a non-conductive body and a conductive bezel, the bezel comprises a support portion that supports the underside of the cover crystal, and wherein, in a side view seen from a direction parallel to the surface of the first conductor element, the distance from the underside of the support portion to the first conductor element is 0.012 wavelengths or more of the wavelength of the radio waves received by the antenna, and the distance from the cover crystal to the first conductor element is 0.0238 wavelengths or less of the wavelength of the radio waves. According to the electronic watch with built-in antenna disclosed herein, the antenna can receive radio waves that pass through a non-conductive case, improving reception performance. Also, because the bezel is made of a conductive material such as metal, the scratch resistance and durability of the surface of the electronic watch can be improved, and the appearance of the electronic watch can be made more luxurious. [Explanation of symbols]

[0068] 1...electronic watch, 1B...electronic watch, 1C...electronic watch, 2...dial, 3...hand, 10...case, 10B...case, 10C...case, 11...case body, 12...body, 12B...body, 12C...body, 13...bezel, 13C...bezel, 15...cover crystal, 20...movement, 23...driving mechanism, 31...hour hand, 32...minute hand, 33...second hand, 35...hand axis, 36...hand axis, 37...hand axis, 45...circuit board, 50... Antenna, 50A...through hole, 51...dielectric substrate, 52...first conductor element, 52B...outer surface, 53...second conductor element, 54...short-circuit portion, 70...digital display panel, 70A...liquid crystal display, 80...resin frame, 90...antenna, 91...first conductor element, 92...second conductor element, 93...short-circuit portion, 101...inner surface, 101B...inner surface, 131...surface, 133...support piece, 133A...inner surface, 133C...support piece.

Claims

1. an antenna having a flat-plate-shaped first conductive element, a flat-plate-shaped second conductive element that overlaps with the first conductive element in a plan view seen from a direction perpendicular to a surface of the first conductive element and is disposed below the first conductive element, and a short-circuiting portion that short-circuits the first conductive element and the second conductive element; A time display unit disposed above the antenna; A cover crystal disposed above the time display unit; A power supply section that supplies power to the first conductive element; a conductive case that houses the antenna, the time display unit, and the power supply unit and has an annular side wall; Equipped with The conductive case is a support portion protruding inward from the side wall and supporting a lower surface of the cover glass; In a side view seen in a direction parallel to a surface of the first conductive element, the distance from the lower surface of the support portion to the first conductive element is 0.012 wavelengths or more of the wavelength of the radio wave received by the antenna, and the distance from the cover glass to the first conductive element is 0.0238 wavelengths or less of the wavelength of the radio wave. Electronic clock with built-in antenna.

2. 2. The electronic timepiece with an internal antenna according to claim 1, When viewed from the side, the distance from a lower surface of the support portion to the first conductive element is equal to or greater than 0.014 wavelengths of the radio waves received by the antenna. Electronic clock with built-in antenna.

3. 2. The electronic timepiece with an internal antenna according to claim 1, In the plan view, an inner circumferential surface of the support portion is positioned outside the first conductive element. Electronic clock with built-in antenna.

4. 2. The electronic timepiece with an internal antenna according to claim 1, In the side view, in the range from the lower surface of the support portion to the lower surface of the second conductive element, The distance from the inner peripheral surface of the side wall of the conductive case to the outer peripheral surface of the first conductive element is equal to or greater than 0.008 wavelengths of the radio waves received by the antenna. Electronic clock with built-in antenna.

5. 2. The electronic timepiece with an internal antenna according to claim 1, A distance from an outer peripheral surface of the first conductive element on the opposite side of the short circuit portion to an inner peripheral surface of the side wall of the conductive case is greater than a distance from an outer peripheral surface of the first conductive element at the short circuit portion to an inner peripheral surface of the side wall of the conductive case. Electronic clock with built-in antenna.

6. 2. The electronic timepiece with an internal antenna according to claim 1, The time display unit includes a dial and a pointer. The antenna is provided with a through hole through which the pointer shaft passes. Electronic clock with built-in antenna.

7. 2. The electronic timepiece with an internal antenna according to claim 1, The time display unit is a digital display panel. Electronic clock with built-in antenna.

8. 2. The electronic timepiece with an internal antenna according to claim 1, The conductive case is A conductive bezel having the support portion; a conductive body that houses the antenna, the time display unit, and the power supply unit; The surface of the bezel is decorated. Electronic clock with built-in antenna.

9. an antenna having a flat-plate-shaped first conductive element, a flat-plate-shaped second conductive element that overlaps with the first conductive element in a plan view seen from a direction perpendicular to a surface of the first conductive element and is disposed below the first conductive element, and a short-circuiting portion that short-circuits the first conductive element and the second conductive element; A time display unit disposed above the antenna; A cover crystal disposed above the time display unit; A power supply section that supplies power to the first conductive element; a case that houses the antenna, the time display unit, and the power supply unit; Equipped with The case has a non-conductive body and a conductive bezel; the bezel includes a support portion that supports a lower surface of the cover glass, In a side view seen in a direction parallel to a surface of the first conductive element, the distance from the lower surface of the support portion to the first conductive element is 0.012 wavelengths or more of the wavelength of the radio wave received by the antenna, and the distance from the cover glass to the first conductive element is 0.0238 wavelengths or less of the wavelength of the radio wave. Electronic clock with built-in antenna.

Images