Patent Publication Number: US-9886003-B2

Title: Electronic timepiece

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to an electronic timepiece, and relates more particularly to an electronic timepiece with a planar antenna. 
     2. Related Art 
     JP-A-2012-13627 describes an electronic timepiece with a planar antenna for receiving radio frequency signals transmitted from GPS (Global Positioning System) or other types of positioning information satellites. 
     The electronic timepiece in JP-A-2012-13627 has a planar antenna disposed on the back cover side of the dial, and suppresses loss of antenna sensitivity by separating the planar antenna from the metal case around the antenna. 
     Disposing the planar antenna closer to the base plate that is also disposed on the back cover side of the dial is desirable to make the electronic timepiece thinner. Because the base plate is made of plastic or other non-conductive material, the base plate does not interfere with radio waves, and the planar antenna can receive radio signals even with the planar antenna disposed adjacent to the base plate. 
     Because the base plate is a dielectric, however, a new problem of the antenna frequency shifting occurs if the gap between the base plate and the antenna electrode is too small. More specifically, the antenna frequency begins shifting if the gap between the base plate and the antenna electrode of the planar antenna is less than approximately 1.0 mm. The problem becomes particularly acute if this gap is 0.5 mm or less because the frequency shift increases with even the slightest change in the gap between the base plate and the antenna electrode, reception performance drops, and antenna characteristics are not stable. 
     SUMMARY 
     The present invention provides an electronic timepiece that is thin and maintains stable antenna characteristics. 
     An electronic timepiece according to a preferred aspect of the invention has a base plate made from a non-conductive material; and a planar antenna disposed on the back cover side of the base plate and including a dielectric substrate and an antenna electrode disposed to the surface of the dielectric substrate on the base plate side, and an exposed surface where the antenna electrode is not present formed on the surface of the dielectric substrate. The base plate has a through-hole overlapping the antenna electrode at least in part in plan view, and a cover part overlapping the exposed surface at least in part in plan view. 
     Because a through-hole that overlaps the antenna electrode of the planar antenna in plan view is formed in the base plate, less of the base plate or dielectric is in proximity to the antenna electrode when the planar antenna is placed close to the base plate than when a through-hole is not formed, the shift in the antenna frequency can be reduced, and antenna performance can be stabilized. Furthermore, because the planar antenna can be located near the base plate, the movement that houses the planar antenna can also be made thinner, and an electronic timepiece having the movement can be made thinner. 
     A cover part that overlaps at least part of the exposed surface in plan view is also formed to the base plate. As a result, movement of the planar antenna to the base plate side can be limited by the exposed surface directly or indirectly contacting the cover part. The planar antenna can therefore be prevented from passing through the through-hole in the base plate and striking the dial or other member in the event the electronic timepiece is dropped, for example. 
     An electronic timepiece preferably also has a shock absorber is disposed between the cover part and the exposed surface. 
     Because a shock absorber is placed between the cover parts of the base plate and the exposed surface of the dielectric substrate, the planar antenna can be precisely positioned in the height (thickness) direction of the electronic timepiece by setting the exposed surface of the planar antenna against the shock absorber. As a result, the positioning precision of the planar antenna to the base plate can be improved, change in the antenna frequency due to deviation in positioning precision can be further reduced, and antenna performance can be further stabilized. 
     Furthermore, because the exposed surface of the planar antenna contacts a sponge or other shock absorbing member, direct contact with the cover parts can be prevented. Damage to the ceramic dielectric substrate can also be prevented even if the dielectric substrate of the planar antenna is made from a hard, easily chipped ceramic because the dielectric substrate does not directly contact the base plate. 
     In an electronic timepiece according to another aspect of the invention, the through-hole is formed overlapping at least all of the antenna electrode in plan view. 
     In this aspect of the invention a through-hole formed in the base plate is made so that it does not completely overlap the antenna electrode in plan view. Because a through-hole in the base plate is therefore opposite the antenna electrode and the dielectric base plate is not opposite the antenna electrode, change in the antenna frequency can be further reduced and stable antenna performance can be achieved. In addition, the antenna electrode can be disposed in the through-hole in the base plate, and the thickness of the movement can be reduced. 
     An electronic timepiece according to another aspect of the invention also has a calendar wheel made from a non-conductive material and displaying calendar information; and the planar antenna is disposed to a position overlapping the calendar wheel in plan view. 
     Because the date wheel or other calendar wheel is made from a non-conductive material, there is no interference with signal reception even if the calendar wheel overlaps the planar antenna in plan view. Furthermore, because the pivots of the hour, minute, and second hands and other information indicators pass through the dial and base plate, the pivots must be disposed to plane positions outside the area of the date wheel and planar antenna. As a result, disposing the planar antenna to a position overlapping the calendar wheel in plan view affords greater freedom locating the pivots than a configuration in which the planar antenna and calendar wheel do not overlap, and thereby provides greater freedom designing the electronic timepiece. 
     An electronic timepiece according to another aspect of the invention preferably also has a solar panel disposed to the face side of the base plate not overlapping the planar antenna in plan view. 
     For example, the solar panel can be disposed not overlapping the planar antenna by creating a notch in the solar panel at a position superimposed with the planar antenna in plan view. 
     The solar panel includes electrodes, but because the solar panel and the planar antenna do not overlap each other in plan view in the invention, radio waves passing from the face side of the timepiece are picked up by the antenna without being obstructed by the solar panel. A solar panel can therefore be provided in the electronic timepiece without reducing reception performance. 
     Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an electronic timepiece according to the invention. 
         FIG. 2  is a plan view of the electronic timepiece. 
         FIG. 3  is a section view of the electronic timepiece. 
         FIG. 4  is a partially exploded oblique view of the electronic timepiece. 
         FIG. 5  is a section view illustrating the relative positions of the planar antenna and a through-hole in the base plate of the electronic timepiece. 
         FIG. 6  is a plan view illustrating the relative positions of the planar antenna and a through-hole in the base plate of the electronic timepiece. 
         FIG. 7  is a section view illustrating the configuration of the planar antenna in the electronic timepiece. 
         FIG. 8  is a block diagram illustrating the circuit design of the electronic timepiece. 
         FIG. 9  is a section view illustrating the relative positions of the planar antenna and a through-hole in the base plate of an electronic timepiece according to another embodiment of the invention. 
         FIG. 10  is an oblique view illustrating the planar antenna and circuit board of the electronic timepiece according to another embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A preferred embodiment of the present invention is described below with reference to the accompanying figures. Note that the crystal  31  side of the electronic timepiece  1  according to this embodiment of the invention is also referred to as the face, front, or top side, and the back cover  12  side is also referred to as the back or bottom side of the electronic timepiece  1 . 
     As shown in  FIG. 1  and  FIG. 2 , the electronic timepiece  1  is a wristwatch with a time display unit for displaying the time using a dial  2  and hands  3 , an information display unit including a subdial  2 A of the dial  2  and a hand  4 , and a calendar display unit including a window  2 B in the dial  2  and a date wheel  5 . 
     The dial  2  is a disc-shaped member made of polycarbonate or other non-conductive material. The subdial  2 A is located at 6:00 on the dial  2 , and the window  2 B is located at 3:00 on the dial  2 . In addition to the subdial  2 A and window  2 B, the dial  2  has a through-hole  2 C through which the center pivot  3 A of the hands  3  passes, and a through-hole  2 D through which the pivot  4 A of the small hand  4  passes, as shown in  FIG. 3  and  FIG. 4 . Note that the information display unit comprising the subdial  2 A and hand  4  (small hand) may be used to indicate the current operating mode of the timepiece, the day of the week, the remaining battery capacity, or other information. 
     The hands  3  include a second hand, minute hand, and hour hand. The hands  3 ,  4  and date wheel  5  are driven by a drive mechanism including a stepper motor and wheel train described further below. 
     The electronic timepiece  1  also has a crown  6  and buttons  7  and  8  as external operating members. 
     The electronic timepiece  1  receives satellite signals and acquires satellite time information from the plural GPS satellites S orbiting the Earth on known orbits, and can correct internal time information based on the acquired satellite time information. 
     Note that the GPS satellites S shown in  FIG. 1  are just one example of positioning information satellites, and numerous GPS satellites S are in orbit. There are presently approximately 30 GPS satellites S in service. 
     External Structure of the Electronic Timepiece 
     As shown in  FIG. 2  and  FIG. 3 , the electronic timepiece  1  has a case  10  that houses a movement  20  described further below. The case  10  includes the main case  11 , and the back cover  12 . 
     The main case  11  includes a tubular outside case member  111 , and a bezel  112  disposed on the front side of the outside case member  111 . 
     The bezel  112  is shaped like a ring with the outside of the bezel  112  continuous to the outside of the outside case member  111 . The bezel  112  and outside case member  111  are connected by an interlocking tongue-and-groove structure formed on their mutual opposing surfaces, or by adhesive or double-sided adhesive tape, for example. The bezel  112  may also be attached so that it can rotate on the outside case member  111 . 
     The crystal  31  is attached to the inside of the bezel  112  as a cover member held by the bezel  112 . 
     A round back cover  12  is disposed to the back cover side of the outside case member  111  covering the back cover side opening to the outside case member  111 . The back cover  12  and the outside case member  111  screw together. 
     Note that the outside case member  111  and the back cover  12  are discrete members in this embodiment of the invention, but the invention is not so limited and the outside case member  111  and back cover  12  may be formed in unison as a single piece. 
     The outside case member  111 , bezel  112 , and back cover  12  are made of brass, stainless steel, titanium alloy, or other conductive metal material. 
     Internal Configuration of the Electronic Timepiece 
     The internal structure housed in the case  10  of the electronic timepiece  1  is described next. 
     As shown in  FIG. 2 ,  FIG. 3 , and  FIG. 4 , a movement  20 , planar antenna  40  (patch antenna), date wheel  5 , and dial ring  32  are housed in addition to the dial  2  inside the case  10 . 
     The movement  20  includes the base plate  21 , a drive module  22  supported by the base plate  21 , a circuit board  23 , a storage battery  24 , and a solar panel  25 . 
     The base plate  21  is made from plastic or other non-conductive material. The base plate  21  includes a drive module housing  21 A that holds the drive module  22 , a date wheel housing  21 B where the date wheel  5  is disposed, and an antenna housing  21 C that holds the planar antenna  40 . 
     The date wheel housing  21 B is a ring-shaped area on the outside side of plural guide parts  213  that protrude up from the face side (the dial  2  side) of the base plate  21 . Movement in the plane direction of the date wheel  5  disposed in the date wheel housing  21 B is limited by the guide parts  213 . 
     The drive module housing  21 A and antenna housing  21 C are disposed on the back side of the base plate  21 . As shown in  FIG. 5  and  FIG. 6 , the antenna housing  21 C has four walls  214  (only two shown in  FIG. 5 ) facing the four sides of the planar antenna  40 , and four cover parts  215  (only two shown in  FIG. 5 ) protruding from the walls  214  and opposing the front side of the planar antenna  40 . A through-hole  216  overlapping at least part of the antenna electrode  42  of the planar antenna  40  in plan view is formed between the cover parts  215 . Note that the four walls  214  are formed in unison, and the four cover parts  215  are formed in unison. 
     Because the antenna housing  21 C is at 12:00 on the dial  2  in plan view, the planar antenna  40  is also located at 12:00 as shown in  FIG. 2 . 
     The drive module  22  is held in the drive module housing  21 A of the base plate  21 , and drives the time display unit, information display unit, and date display unit. More specifically, the drive module  22  includes a drive mechanism  221  with a stepper motor and wheel train for driving the hands  3 , a drive mechanism  222  with a stepper motor and wheel train for driving the hand  4 , and a drive mechanism  223  including a stepper motor and wheel train for driving the date wheel  5  (see  FIG. 4 ). 
     The top side of the circuit board  23  contacts the back side of the base plate  21 , and is attached to the base plate  21  by screw or other fastener. The planar antenna  40  is mounted on the face side of the circuit board  23 . A reception module  50  that processes satellite signals received from the GPS satellites S, and a control unit  61  that controls the drive mechanisms  221  to  223 , are mounted on the back side of the circuit board  23 . The reception module  50  and control unit  61  are located on the opposite side of the circuit board  23  as the planar antenna  40 . The reception module  50  and control unit  61  are also enclosed in a shield  26 . As a result, signals received by the planar antenna  40  are protected from noise produced by the reception module  50  and control unit  61 . 
     A lithium ion battery is used for the storage battery  24 . The storage battery  24  supplies power to the drive module  22 , reception module  50 , and control unit  61 . The storage battery  24  is also disposed to the back side of the circuit board  23  at a position not overlapping the reception module  50  and control unit  61  in plan view. 
     The surface electrode on the top side of the solar panel  25  is made from indium tin oxide (ITO) or other transparent electrode material to pass light. A amorphous silicon semiconductor thin film is formed as the photovoltaic layer on a plastic film base layer. 
     Because GPS satellite signals are high frequency signals of approximately 1.5 GHz, GPS signals are attenuated by even the thin transparent electrode of the solar panel, unlike the long wave standard time signals that are received by radio-controlled timepieces, and antenna performance drops. As a result, a notch  251  is formed in the disc-shaped solar panel  25  at the position overlapping the planar antenna  40  in plan view. The solar panel  25  therefore covers the face side of the base plate  21  but does not cover the planar antenna  40 . The planar antenna  40  can therefore receive radio waves through the notch  251  in the solar panel  25 . 
     Note that an opening  252  superimposed in plan view with the window  2 B in the dial  2 , a hole  253  through which the center pivot  3 A of the hands  3  passes, and a hole  254  through which the pivot  4 A of the small hand  4  passes, are also formed in the solar panel  25 . 
     The planar antenna  40 , which is a patch antenna (microstrip antenna), is disposed in the antenna housing  21 C. The planar antenna  40  receives satellite signals from GPS satellites S. The planar antenna  40  is described further below in detail. 
     The date wheel  5 , which is a ring-shaped calendar wheel having date numbers displayed on the surface, is held in the date wheel housing  21 B of the base plate  21 . The date wheel  5  is made from plastic or other non-conductive material. In plan view, the date wheel  5  overlaps at least part of the planar antenna  40 . Note that the calendar wheel is not limited to a date wheel  5 , and may be a day wheel showing the days of the week, or a month wheel showing the months. 
     The dial  2  is disposed to the face side of the base plate  21  covering the solar panel  25  and the date wheel  5 . The dial  2  is made from a material such as plastic that is non-conductive and transparent to at least some light. 
     Abbreviations or other markings can be disposed to the surface of the dial  2  overlapping the planar antenna  40  in plan view. To improve the reception performance of the planar antenna  40 , these parts are preferably made from plastic or other non-conductive material instead of metal. 
     Because the dial  2  is transparent, the solar panel  25  located on the back side of the dial  2  can be seen through the dial  2  from the front of the timepiece. The color of the dial  2  appears different in the areas where the solar panel  25  is present and where the solar panel  25  is not present. Design accents may be added to the dial  2  so that this color different is not conspicuous. 
     By forming the notch  251  in the solar panel  25 , the color tone of the dial  2  in the part overlapping the notch  251  appears different from the tone in other parts of the dial  2 . To prevent this, a plastic sheet of the same color (such as dark blue or purple) as the solar panel  25  may be disposed below the solar panel  25 , or the signal-blocking electrode layer may be removed only in the part overlapping the planar antenna  40  in plan view instead of cutting completely through the solar panel  25  so that the plastic film base layer remains and the color of the solar panel  25  is the same throughout. 
     A dial ring  32  that is made of a plastic non-conductive material in a ring shape is disposed to the face side of the dial  2 . The dial ring  32  is disposed around the circumference of the dial  2 , is conically shaped with the inside circumference surface sloping down to the dial  2 , and has 60 minute markers printed on the inside sloping surface. The dial ring  32  is held pressed against the dial  2  by the bezel  112 . 
     In plan view, the planar antenna  40  does not overlap the main case  11  (outside case member  111  and bezel  112 ) and solar panel  25 , but does overlap the date wheel  5 , dial  2 , and crystal  31 , which are made from non-conductive materials. More specifically, all parts of the electronic timepiece  1  that are over the face side of the planar antenna  40  in plan view are made from non-conductive materials. 
     As a result, satellite signals passing from the face side of the timepiece pass through the crystal  31 , pass through the dial  2 , date wheel  5 , and base plate  21  without interference from the main case  11  or solar panel  25 , and are incident to the planar antenna  40 . Note that because the hands  3 ,  4  overlap only a small area of the planar antenna  40 , there is no interference with signal reception even if the hands are metal, but the hands are preferably made from a non-conductive material because any interference with signal reception can be avoided. 
     Planar Antenna 
     GPS satellites S transmit right-hand circularly polarized satellite signals. As a result, the planar antenna  40  according to this embodiment is a patch antenna (also called a microstrip antenna) with excellent circular polarization characteristics. 
     As shown in  FIG. 5 , the planar antenna  40  according to this embodiment is a patch antenna having a conductive antenna electrode  42  on a ceramic dielectric substrate  41 . 
     This planar antenna  40  is manufactured as described below. First, barium titanate with a dielectric constant of 60-100 is formed to the desired shape in a press and sintered to complete the ceramic dielectric substrate  41  of the antenna. Aground electrode  43  forming the ground plane (GND) of the antenna is made by screen printing a primarily silver (Ag) paste, for example, on the back side (the side facing the circuit board  23 ) of the dielectric substrate  41 . 
     A radiating antenna electrode  42  that determines the antenna frequency and the polarity of the received signals is formed on the face side of the dielectric substrate  41  (the side facing the base plate  21  and dial  2 ) by the same method as the ground electrode  43 . The antenna electrode  42  is slightly smaller than the surface of the dielectric substrate  41 , and an exposed surface  411  where the antenna electrode  42  is not present is disposed around the antenna electrode  42  on the surface of the dielectric substrate  41 . 
       FIG. 7  illustrates the operating principle of a planar antenna  40  (patch antenna). In  FIG. 7  the dotted lines  45  represent radio waves received by the planar antenna  40 , and the arrows  46  represent the electric lines of force. 
     A square patch antenna resonates when one side is a half wavelength, and a round patch antenna resonates when the diameter is approximately 0.58 wavelength, but the size of the antenna size can be reduced by the wavelength shortening effect of a dielectric. A patch antenna works by the strong electric field around the edge of the patch (antenna electrode  42 ) radiating from the edge into space, and the electric lines of force become stronger with proximity to the antenna and are easily affected by the effects of nearby metals and dielectrics. To receive GPS satellite signals, therefore, the distance between the metal outside case member  111  and the antenna electrode  42  must be at least 3 mm, and is ideally approximately 4 mm. 
     In this example, the walls  214  are located between the planar antenna  40  and outside case member  111 , and the planar antenna  40  is disposed to a position separated at least a specific distance from the inside surface of the outside case member  111 . As a result, a drop in reception performance due to the proximity of the planar antenna  40  to the metal outside case member  111  can be suppressed, and the reception performance required by the electronic timepiece  1  can be assured. 
     The planar antenna  40  is mounted on the circuit board  23 , and is electrically connected to the GPS antenna module, which is the reception module  50  on the back side of the circuit board  23 . The circuit board  23  can also function as a ground plane by connecting the ground electrode  43  of the planar antenna  40  through the ground pattern of the circuit board  23  to the ground node of the reception module  50 . The outside case member  111  and back cover  12  can also be used as the ground plane by connecting the ground node of the reception module  50  through the ground pattern of the circuit board  23  to the metal outside case member  111  or back cover  12 . 
     The planar antenna  40  is held in the antenna housing  21 C by affixing the circuit board  23  to the base plate  21 . Because the planar antenna  40  receives high frequency 1.54542 GHz signals, and includes a ceramic dielectric substrate  41  with a high dielectric constant, the planar antenna  40  is susceptible to the effects of surrounding parts. The base plate  21  is plastic, but has a dielectric constant of 3-4, and affects the reception frequency if the gap between the base plate  21  and the antenna electrode  42  is less than approximately 1.0 mm. More specifically, the antenna frequency may shift and reception performance drop if the gap between the base plate  21  and the antenna electrode  42  varies even slightly. 
     As shown in  FIG. 3  to  FIG. 6 , a through-hole  216  is formed in the antenna housing  21 C of the base plate  21  in the surface opposite the antenna electrode  42  of the planar antenna  40 , that is, the surface on the dial  2  side. 
     The through-hole  216  in this example is formed overlapping all of the antenna electrode  42  in plan view. More specifically, because the antenna electrode  42  is substantially rectangular in plan view, the through-hole  216  is also rectangular in plan view when seen from the dial side of the electronic timepiece  1 . 
     The length W 1  of one side of the rectangular through-hole  216  is greater than the length W 2  of one side of the antenna electrode  42  and less than the length W 3  of one side of the dielectric substrate  41 . Note that as shown in  FIG. 6  the length of each of the four sides of the through-hole  216  is the same, but the through-hole  216  may be formed as a rectangle with different length and width dimensions in plan view. 
     By thus providing a through-hole  216  superimposed in plan view on the antenna electrode  42 , the base plate  21  (dielectric) does not cover and is not closer than 1.0 mm to the antenna electrode  42 , and the antenna frequency is prevented from shifting due to variation in the gap between the antenna electrode  42  and the dielectric base plate  21 . 
     The length W 4  between the walls  214  is greater than length W 3  and is set to a dimension that accommodates the dielectric substrate  41  of the planar antenna  40 . The cover parts  215  protruding from the walls  214  are formed overlapping the exposed surface  411  of the dielectric substrate  41  in plan view. 
     A sponge or other type of shock absorber  47  is also disposed between the exposed surface  411  and the cover parts  215 . The position of the planar antenna  40  in the thickness direction of the timepiece is set by holding the dielectric substrate  41  against the shock absorber  47 . 
     The ceramic dielectric substrate  41  is also hard and easily chipped, but contact between the dielectric substrate  41  and the base plate  21  can be prevented by the intervening shock absorber  47 . Damage to the dielectric substrate  41  by collision with the base plate  21  can therefore also be prevented. 
     Part of the date wheel  5  is also disposed on the dial  2  side of the planar antenna  40 . Because the antenna electrode  42  and date wheel  5  are separated by at least the thickness of the cover parts  215 , the date wheel  5  is prevented from causing the antenna frequency to shift. 
     Circuit Configuration of the Electronic Timepiece 
     The circuit design of the electronic timepiece  1  is described next with reference to  FIG. 8 . 
     As shown in  FIG. 8 , the electronic timepiece  1  has a planar antenna  40 , a SAW filter  35 , the reception module  50 , a display control unit  60 , and a power supply unit  70 . 
     The SAW filter  35  is a bandpass filter that passes signals in the 1.5 GHz waveband. A LNA (low noise amplifier) may also be disposed between the planar antenna  40  and the SAW filter  35  to improve reception sensitivity. 
     Note also that the SAW filter  35  may be embedded in the reception module  50 . 
     The reception module  50  processes satellite signals passed through the SAW filter  35 , and includes an RF (radio frequency) unit  51  and a baseband unit  52 . 
     The RF unit  51  includes a PLL (phase-locked loop) circuit  511 , a VCO (voltage controlled oscillator)  512 , a LNA (low noise amplifier)  513 , a mixer  514 , an IF (intermediate frequency) amplifier  515 , an IF filter  516 , and an A/D converter  517 . 
     The satellite signal passed by the SAW filter  35  is amplified by the LNA  513 , mixed by the mixer  514  with the clock signal output by the VCO  512 , and down-converted to a signal in the intermediate frequency band. 
     The IF signal from the mixer  514  is amplified by the IF amplifier  515 , passed through the IF filter  516 , and converted to a digital signal by the A/D converter  517 . 
     The baseband unit  52  includes, for example, a DSP (digital signal processor)  521 , CPU (central processing unit)  522 , a RTC (real-time clock)  523 , and SRAM (static random access memory)  524 . A TCXO (temperature compensated crystal oscillator)  53  and flash memory  54  are also connected to the baseband unit  52 . 
     A digital signal is input from the A/D converter  517  of the RF unit  51  to the baseband unit  52 , which acquires satellite time information and navigation information by a correlation process and positioning computation process. 
     Note that the clock signal for the PLL circuit  511  is generated by the TCXO  53 . 
     The display control unit  60  includes a control unit (CPU)  61 , a drive circuit  62  that drives the hands  3 ,  4 , a time display unit, and information display unit. 
     The control unit  61  includes a RTC  611  and storage unit  612 . 
     The RTC  611  calculates the internal time information using a reference signal output from a crystal oscillator  63 . 
     The storage unit  612  stores the satellite time information and positioning information output from the reception module  50 . Time difference data corresponding to the positioning information is also stored in the storage unit  612 , and the local time at the current location can be calculated from the time difference data and the internal time kept by the RTC  611 . 
     The electronic timepiece  1  in this example can also automatically correct the displayed time based on the satellite signals received from the GPS satellites S using the reception module  50  and display control unit  60  described above. 
     The power supply unit  70  includes the solar panel  25 , a charging control circuit  71 , the storage battery  24 , a first regulator  72 , a second regulator  73 , and a voltage detection circuit  74 . 
     When light is incident and the solar panel  25  produces power, the power obtained by photovoltaic generation is passed by the charging control circuit  71  to the storage battery  24  to charge the storage battery  24 . 
     The storage battery  24  supplies drive power through the first regulator  72  to the display control unit  60 , and supplies power through the second regulator  73  to the reception module  50 . 
     The voltage detection circuit  74  monitors the output voltage of the storage battery  24 , and outputs to the control unit  61 . The control unit  61  can therefore know the storage battery  24  voltage and control the reception process. 
     Operating Effect 
     By forming a through-hole  216  in the base plate  21  overlapping all of the antenna electrode  42  of the planar antenna  40  in plan view, the base plate  21  is not present near the antenna electrode  42 , and the antenna frequency is prevented from shifting due to the dielectric base plate  21  being close to the antenna electrode  42 . As a result, variation in the antenna frequency is reduced and antenna performance is stabilized. 
     Furthermore, because a through-hole  216  is opposite the antenna electrode  42 , the distance between the exposed surface  411  of the planar antenna  40  and the cover parts  215  of the base plate  21  can be reduced. As a result, the movement  20  housing the planar antenna  40  inside can be made thinner, and the electronic timepiece  1  can also be made thinner. 
     Furthermore, because cover parts  215  that overlap at least part of the exposed surface  411  of the planar antenna  40  in plan view are formed with the base plate  21 , the planar antenna  40  can be prevented from moving to the face side of the timepiece. The planar antenna  40  can therefore be prevented from passing through the through-hole  216  in the base plate  21  and striking the dial  2  or date wheel  5  in the event the electronic timepiece  1  is dropped, for example. 
     Furthermore, because a shock absorber  47  is placed between the cover parts  215  of the base plate  21  and the exposed surface  411  of the dielectric substrate  41 , and the exposed surface  411  of the planar antenna  40  is set against the shock absorber  47 , the planar antenna  40  can be precisely positioned in the height (thickness) direction of the electronic timepiece  1 . As a result, the positioning precision of the planar antenna  40  to the base plate  21  can be improved, change in the antenna frequency due to deviation in positioning precision can be further reduced, and antenna performance can be further stabilized. 
     Furthermore, because the exposed surface  411  of the planar antenna  40  contacts the shock absorber  47 , direct contact with the cover parts  215  can be prevented, and damage to the ceramic dielectric substrate  41  can be prevented. 
     Furthermore, because the date wheel  5  is made from a non-conductive material, a drop in reception performance can be prevented even if the date wheel  5  overlaps the planar antenna  40  in part in plan view because the satellite signals can pass through the date wheel  5  to the antenna. 
     Furthermore, because the date wheel  5  overlaps the planar antenna  40  in plan view, there is greater freedom positioning the center pivot  3 A and pivot  4 A of the hands  3  and small hand  4  to avoid the date wheel  5  and planar antenna  40 , and the electronic timepiece  1  can be designed with a greater degree of freedom. 
     Furthermore, because the planar antenna  40  does not overlap the solar panel  25  in plan view, satellite signals passed from the face side of the timepiece are incident to the planar antenna  40  without being obstructed by the solar panel  25 . A solar panel  25  can therefore be disposed to the electronic timepiece  1  without reducing reception performance. 
     Because the planar antenna  40  does not overlap the main case  11  (outside case member  111  and bezel  112 ) in plan view when seen from the front of the timepiece, satellite signals pass from the front of the timepiece through the crystal  31  and are incident to the planar antenna  40  without being obstructed by the main case  11 . Metal or other conductive material can therefore be used for the main case  11  and back cover  12  without reducing reception performance, and the apparent quality of the electronic timepiece  1  can be improved. 
     Furthermore, because the bezel  112  is made from a conductive material, the bezel  112  can be manufactured more easily than when using ceramic, freedom of design can therefore be improved, and cost can be reduced. Furthermore, because the bezel  112  is metal, greater rigidity can be achieved in a smaller sectional area than with a ceramic bezel. The sectional width of the ring-shaped bezel  112  can therefore be reduced, the planar size of the crystal  31  can be increased, and 
     the freedom of timepiece design can be improved. 
     Furthermore, because the outside case member  111  and back cover  12  are connected to ground of the reception module  50 , they can also function as the ground plane. As a result, the area of the ground plane can be increased, antenna gain can be improved, and antenna performance can be improved. 
     Other Embodiments 
     The invention is not limited to the embodiment doves, and can be varied in many ways without departing from the technical scope of the invention. 
     The through-hole  216  formed in the antenna housing  21 C of the base plate  21  is preferably sized to overlap the entire antenna electrode  42  of the planar antenna  40  in plan view. As shown in  FIG. 9 , however, the length W 1  of one side of the through-hole  216  may be made smaller than the length W 2  of one side of the antenna electrode  42 , and the cover parts  215  may be formed to overlap part of the antenna electrode  42  in plan view. 
     In this case, compared with when a through-hole  216  is not formed in the base plate  21 , less of the base plate  21  or dielectric body is close to the antenna electrode  42 , the effect of a dielectric causing the antenna frequency to shift can be reduced, and antenna performance can be stabilized. 
     As also shown in  FIG. 9 , when the antenna electrode  42  and the base plate  21  (cover parts  215 ) overlap in plan view, the area of overlap is preferably as small as possible to reduce the antenna frequency shifting effect, and the area of overlap is preferably 30% or less of the area of the antenna electrode  42 . 
     A circuit board  23 A and a planar antenna  40 A as shown in  FIG. 10  may also be used. To make the electronic timepiece  1  thinner, a through-hole  231  is formed in the part of the circuit board  23 A overlapping the storage battery  24  in plan view. The thickness of the movement  20  can then be reduced by disposing the stepper motor, wheel train, and other parts of the drive module  22  to positions not overlapping the storage battery  24  in plan view. 
     The reception module  50 , control unit  61 , and other circuit components are mounted on the circuit board  23 A on the opposite side as the side on which the planar antenna  40 A is mounted. As a result, as described in the foregoing embodiment, the planar antenna  40  is shielded from digital noise from the reception circuit and power supply circuit, and reception sensitivity can be improved. 
     The antenna electrode  42 A on the surface of the dielectric substrate  41 A of the planar antenna  40 A is formed at a position offset toward the planar center of the circuit board  23 A, that is, offset toward the planar center of the electronic timepiece  1 . As a result, in the exposed surface  411 A on the surface of the dielectric substrate  41 A, the width D 1  of the exposed surface  411 A from the antenna electrode  42 A to the outside case member  111  side is greater than the width D 2  of the exposed surface  411 A from the antenna electrode  42 A to the planar center of the circuit board  23 A. More specifically, the planar center of the antenna electrode  42 A does not match the planar center of the dielectric substrate  41 A, and is closer to the planar center of the electronic timepiece  1  than the planar center of the dielectric substrate  41 A. 
     In plan view, the width D 1  can also be expressed as the distance from the side of the antenna electrode  42 A closest to the outside case member  111  to the side of the dielectric substrate  41 A closest to the outside case member  111 . Width D 2  can also be expressed as the distance from the side of the antenna electrode  42 A closest to the planar center of the electronic timepiece  1  to the side of the dielectric substrate  41 A closest to the planar center of the electronic timepiece  1 . 
     By disposing the planar antenna  40 A with the antenna electrode  42 A separated from the metal outside case member  111 , the radio frequency shielding effect of the metal outside case member  111  can be reduced. 
     The embodiment described above has a shock absorber  47 , but this shock absorber  47  may be omitted. In this case, the exposed surface  411  of the planar antenna  40  may be set in contact with the cover parts  215 . The exposed surface  411  of the planar antenna  40  may also be disposed not touching the cover parts  215  with a gap therebetween. 
     The main case  11  in the foregoing embodiment includes a outside case member  111  and bezel  112 , but the invention is not so limited. More specifically, the main case  11  may comprise only an outside case member  111 . 
     The bezel  112  in the foregoing embodiment is made from a conductive material, but the invention is not so limited. For example, the bezel  112  may be made of a ceramic such as zirconia (ZrO 2 ), which is a non-conductive material. Zirconia has high resistivity, does not adversely affect signal reception, is hard, offers excellent scratch resistance, and is outstanding when used as an external member of a timepiece. If the bezel  112  is ceramic, the bezel  112  and the antenna electrode  42  may overlap in plan view. As a result, there is no need to increase the diameter of the outside case member  111  so that the bezel  112  does not overlap the antenna electrode  42  in plan view, the diameter of the outside case member  111  can be reduced, and the plane size of the electronic timepiece  1  can be reduced. 
     The electronic timepiece  1  in the foregoing embodiment has a date wheel  5 , solar panel  25 , and dial ring  32 , but the invention is not so limited. More specifically, the electronic timepiece may be made without a date wheel  5 , solar panel  25 , and dial ring  32 . 
     The outside case member  111  and back cover  12  touch the ground of the reception module  50  in the foregoing embodiments, but the invention is not so limited. More specifically, the outside case member  111  and back cover  12  do not need to connect to the ground. 
     The electronic timepiece in the foregoing embodiments has a time display unit comprising a dial  2  and hands  3 , but the invention is not so limited. The electronic timepiece may be made with an LCD panel as the time display unit, for example. In this event, the drive module that drives the time display unit may be a drive unit that drives the LCD panel. 
     In this case, the electronic timepiece simply requires a time display function, and the time display unit need not be a display unit for displaying only the time. Examples of such electronic timepieces are wrist-wearable devices such as heart rate monitors that are worn on the user&#39;s wrist to measure the heart rate, and GPS loggers that are worn on the wrist and measure the user&#39;s current location while the user is jogging. 
     The foregoing embodiments are described with reference to a GPS satellite as an example of a positioning information satellite, but the positioning information satellite of the invention is not limited to GPS satellites and the invention can be used with Global Navigation Satellite Systems (GNSS) such as Galileo (EU), GLONASS (Russia), and Beidou (China). The invention can also be used with geostationary satellites in satellite-based augmentation systems (SBAS), and quasi-zenith satellites in radio navigation satellite systems (RNSS) that can only search in specific regions. The invention can also be used in configurations that receive and process satellite signals from multiple systems. 
     The invention being thus described, it will be obvious that it may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 
     The entire disclosure of Japanese Patent Application No. 2014-208140, filed Oct. 9, 2014 is expressly incorporated by reference herein.