Patent Publication Number: US-9897979-B2

Title: Electronic timepiece and control method of an electronic timepiece

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to an electronic timepiece and a control method of an electronic timepiece that receives satellite signals from GPS satellites, for example, or standard time signals from a transmission station, acquires time information, and corrects the time. 
     2. Related Art 
     Electronic timepieces that receive satellite signals from GPS satellites or standard time signals from long-wave standard time signal transmission stations, acquire time information, and correct the time, are known from the literature. See, for example, JP-A-2008-51697. 
     When the remaining battery capacity of the battery in an electronic timepiece is low, there is a chance that the battery voltage will drop to the system shutdown level of the controller chip if the signal reception operation is executed. It is therefore desirable to check the battery voltage before operating the reception unit, and apply control to not run the reception operation if the battery level is less than a specific value. 
     The power required to drive a satellite signal receiver that receives satellite signals is approximately 500 times the power required to drive a standard time signal receiver, however. 
     Therefore, if a value that will not drop to the system shutdown level if the satellite signal receiver operates is set as the threshold value of the battery voltage for automatically executing the reception process, the automated reception process will not execute even if the battery voltage is a level at which the standard time signal receiver can operate. The deviation of the time kept by the timekeeping device may therefore increase compared with when the automated reception process is executed by the standard time signal receiver. 
     SUMMARY 
     The present invention is directed to an electronic timepiece having a satellite signal receiver and a standard time signal receiver, and a control method of an electronic timepiece, that can increase opportunities for operating the standard time signal receiver and can minimize deviation in the internal time kept by the timekeeping device. 
     An electronic timepiece has: a satellite signal receiver that receives satellite signals and acquires time information; a standard time signal receiver that receives a standard time signal and acquires time information; a battery that supplies power to the satellite signal receiver and the standard time signal receiver; a reserve power detector that detects the reserve power of the battery; a satellite signal reception controller that controls operation of the satellite signal receiver when a previously set automatic reception condition for the satellite signal is met; and a standard time signal reception controller that controls operation of the standard time signal receiver when a previously set automatic reception condition for the standard time signal is met. The satellite signal reception controller operates the satellite signal receiver if the automatic reception condition for the satellite signal is met and the reserve power detected by the reserve power detector is greater than or equal to a first threshold; and does not operate the satellite signal receiver if the automatic reception condition for the satellite signal is met and the reserve power detected by the reserve power detector is less than the first threshold. The standard time signal reception controller operates the standard time signal receiver if the automatic reception condition for the standard time signal is met when the reserve power detected by the reserve power detector is greater than or equal to the first threshold and when the reserve power is less than the first threshold. 
     Because the electronic timepiece has reception units for receiving two types of signals, a satellite signal receiver and a standard time signal receiver, the probability of being able to acquire time information can be improved. Furthermore, because the satellite signal receiver is set to operate by the satellite signal reception controller only if the automatic reception condition is met when the battery voltage is greater than or equal to a first threshold, the system can be reliably prevented from shutting down due to the battery voltage dropping as a result of the satellite signal receiver operating. Because the standard time signal receiver is set to operate by the standard time signal reception controller even if the battery voltage is less than the first threshold, the standard time signal receiver can operate when the battery voltage is less than the first threshold. As a result, more opportunities for the standard time signal receiver to operate can be created, and deviation in the kept time can be reduced. 
     Preferably in an electronic timepiece according to another aspect, the standard time signal reception controller determines the automatic reception condition for the standard time signal is met and operates the standard time signal receiver when the time kept by the electronic timepiece reaches a previously set reception time; and the satellite signal reception controller operates the satellite signal receiver when the standard time signal receiver operated by the standard time signal reception controller does not succeed at acquiring time information by receiving the standard time signal, the electronic timepiece is determined to be outdoors, and the reserve power is greater than or equal to the first threshold. 
     The standard time signal reception controller can also execute the standard time signal reception process every day at a scheduled time because the standard time signal receiver operates when the kept time reaches a set reception time. Because the satellite signal reception controller operates the satellite signal receiver only when receiving a standard time signal reception and acquiring time information is not successful, the satellite signal receiver can be operated when operation of the standard time signal receiver is prioritized but a standard time signal cannot be received, and when a standard time signal was received but time information could not be acquired. As a result, time information can be acquired by the low current consumption standard time signal receiver when the electronic timepiece is used in a place where a standard time signal can be received, and time information can be acquired by the satellite signal receiver when in a location where a standard time signal cannot be received. Power consumption by the reception process for acquiring time information can therefore be suppressed. 
     Further preferably in an electronic timepiece according to another aspect, the satellite signal receiver can execute a timekeeping reception process to acquire time information based on the satellite signal, and a positioning reception process to calculate positioning information based on the satellite signal; and when the located identified by the positioning information acquired by the positioning reception process is outside a previously set standard time signal reception area, the standard time signal reception controller does not operate the standard time signal receiver, and the satellite signal reception controller operates the satellite signal receiver if the reserve power is greater than or equal to the first threshold and the electronic timepiece is determined to be outdoors. 
     Because whether or not the location enables receiving a standard time signal is determined from the positioning information acquired by the positioning reception process, unnecessary operation of the standard time signal receiver when not in an area where a standard time signal can be received can be prevented. 
     Further preferably, the satellite signal receiver can execute a timekeeping reception process to acquire time information based on the satellite signal, and a positioning reception process to calculate positioning information based on the satellite signal; and the satellite signal reception controller operates the satellite signal receiver and executes the timekeeping reception process when a previously set timekeeping reception condition is met and the reserve power is greater than or equal to the first threshold, and operates the satellite signal receiver and executes the positioning reception process when a previously set positioning reception condition is met and the reserve power is greater than or equal to a second threshold that is greater than the first threshold. 
     Because the positioning reception process, which consumes more power than the timekeeping reception process, executes only when the power reserve is greater than or equal to a second threshold, which is higher than the first threshold, battery power can be reliably prevented from dropping to the system shutdown level by the positioning reception process. Furthermore, because the first threshold can be set based on the current consumption of the timekeeping reception process, more opportunities to execute the timekeeping reception process can be created than if the first threshold is set according to the positioning reception process. 
     Further preferably, the satellite signal reception controller operates the satellite signal receiver when a reception operation of an operating member is detected, and the reserve power is greater than or equal to a threshold that is lower than the threshold set for the automatic reception condition. 
     The satellite signal reception controller operates the satellite signal receiver if the reception operation of an operating member such as a button disposed to the electronic timepiece is performed and the reserve battery power is greater than or equal to a threshold. Because this threshold is lower than the threshold for the automated reception process, more opportunities to execute the satellite signal reception process when the user starts reception manually can be created. A drop in user convenience resulting from the reception process not executing in response to this reception operation can therefore be prevented. 
     An electronic timepiece according to another aspect preferably also has a solar cell; and a power output detector that detects the power output of the solar cell. The satellite signal reception controller determines whether or not the electronic timepiece is outdoors based on the power output detected by the power output detector, and determines the automatic reception condition for the satellite signal is met if the electronic timepiece is determined to be outdoors. 
     Because being outdoors can be determined by the power output detector detecting the power output of the solar cell, the satellite signal reception controller can determine if the electronic timepiece is outdoors where satellite signal reception is easy. The probability of satellite signal reception succeeding automatically can therefore be improved. 
     An electronic timepiece according to another aspect preferably also has a display able to display the reserve power detected by the reserve power detector, and the display displays the reserve power at least when reception starts. 
     Because the electronic timepiece has a display for displaying the remaining battery capacity, the remaining battery capacity can be displayed when reception starts, and the user can know if the reception process did not execute because of a low battery. Because the user can thus know why reception failed, the user can take appropriate action to charge the battery to meet the reception condition, and user convenience can be improved. 
     An electronic timepiece according to another aspect preferably also has a hand; and a motor that drives the hand; the standard time signal receiver includes a bar antenna for receiving a standard time signal; and the satellite signal receiver has a ring antenna for receiving a satellite signal. The motor, the bar antenna, and the battery are disposed in a plan view of the electronic timepiece on the inside circumference side of the ring antenna at mutually non-overlapping plane positions. 
     Thus comprised, the thickness of the electronic timepiece can be minimized because parts that are relatively thick, such as the ring antenna, motor, bar antenna, and battery are disposed at positions not overlapping each other in plan view. 
     An electronic timepiece according to another aspect preferably also has a hand; and a motor that drives the hand; and the standard time signal receiver includes a bar antenna for receiving a standard time signal; and the satellite signal receiver includes a patch antenna for receiving a satellite signal. The motor, the bar antenna, the patch antenna, and the battery are disposed in a plan view of the electronic timepiece at mutually non-overlapping plane positions. 
     Thus comprised, the thickness of the electronic timepiece can be minimized because parts that are relatively thick, such as the patch antenna, motor, bar antenna, and battery are disposed at positions not overlapping each other in plan view. 
     Another aspect is a control method of an electronic timepiece including a satellite signal receiver that receives satellite signals and acquires time information; a standard time signal receiver that receives a standard time signal and acquires time information; a battery that supplies power to the satellite signal receiver and the standard time signal receiver; a reserve power detector that detects the reserve power of the battery; and a reception controller. The control method comprises steps of the reception controller: operating the satellite signal receiver if the automatic reception condition for the satellite signal is met when the reserve power detected by the reserve power detector is greater than or equal to a first threshold; not operating the satellite signal receiver if the automatic reception condition for the satellite signal is met when the reserve power detected by the reserve power detector is less than the first threshold; and operating the standard time signal receiver if the automatic reception condition for the standard time signal is met when the reserve power detected by the reserve power detector is greater than or equal to the first threshold or is less than the first threshold. 
     This aspect has the same effect as the electronic timepiece described above. 
     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  is a plan view showing an electronic timepiece according to a preferred embodiment. 
         FIG. 2  shows the face of the electronic timepiece. 
         FIG. 3  is a section view of the electronic timepiece. 
         FIG. 4  is a section view of the electronic timepiece. 
         FIG. 5  shows the arrangement of the motors, battery, and bar antenna in the electronic timepiece. 
         FIG. 6  is a partially exploded oblique view showing main parts of the electronic timepiece. 
         FIG. 7  is a block diagram illustrating the circuit design of the electronic timepiece. 
         FIG. 8  illustrates standard time signal reception areas. 
         FIG. 9  shows the time code format of the JJY standard time signal. 
         FIGS. 10A, 10B and 10C  illustrate the configuration of a GPS satellite signal. 
         FIG. 11  is a block diagram showing the configuration of the controller of the electronic timepiece. 
         FIG. 12  is a flow chart of the automated reception process in this embodiment. 
         FIG. 13  is a flowchart of the timekeeping reception process in this embodiment. 
         FIG. 14  is a flowchart of the positioning reception process in this embodiment. 
         FIG. 15  is a flow chart of the standard time signal reception process in this embodiment. 
         FIG. 16  is a graph of the relationship between the discharge capacity and battery voltage of the storage battery. 
         FIG. 17  is a plan view of an electronic timepiece according to another aspect. 
         FIG. 18  illustrates the relative positions of the motor, battery, bar antenna, and patch antenna in a variation. 
         FIG. 19  is a section view of an electronic timepiece according to another embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A preferred embodiment of the present invention is described below with reference to the accompanying figures. In this embodiment, the crystal  33  side of the electronic timepiece  1  is the face (top, front), and the back cover  34  side is the back (bottom). 
     Electronic Timepiece 
     As shown in  FIG. 1 , the electronic timepiece  1  is configured to receive both standard time signals from a standard time signal receiver R, and satellite signals from a plurality of GPS satellites orbiting the Earth on specific known orbits. 
     The electronic timepiece  1  is configured to receive standard time signals from a standard time signal transmitter R and acquire time information for the country where the transmitter R is located. 
     The electronic timepiece  1  is configured to execute a reception process in a timekeeping mode (timekeeping reception process), and a reception process in a positioning mode (positioning reception process). The timekeeping mode is a mode in which satellite signals are received from one or more GPS satellites, and the internal time of the electronic timepiece  1  is corrected based on the time information contained in the satellite signals. 
     The positioning mode is a mode in which satellite signals are received from three or more (and preferably four or more) GPS satellites, the distance from the electronic timepiece  1  to each of the GPS satellites S and the current location of the electronic timepiece  1  are calculated using the orbit information and time information contained in the satellite signals, the time zone information of the time indicated by the electronic timepiece  1  is corrected based on the current position of the electronic timepiece  1 , and the internal time of the electronic timepiece  1  is corrected based on the time information and time zone information acquired from the satellite signals. 
     When time information is received from a standard time signal, the electronic timepiece  1  corrects the internal time information, which is kept internally by the electronic timepiece  1 , based on the received time information. When time information is received from satellite signals, the electronic timepiece  1  can correct the internal time information based on the received time information and the time zone information. 
     The time zone information can be set based on the positioning information calculated from the satellite signals, and map information stored in the electronic timepiece  1 . The user may also manually select and set the time zone information by operating a button or the crown of the electronic timepiece  1 . 
     Configuration of the Electronic Timepiece 
     The configuration of an electronic timepiece  1  that can receive standard time signals and satellite signals is described next.  FIG. 2  is a front view of the electronic timepiece  1 ,  FIG. 3  is a section view of the electronic timepiece  1  through a line between 3:00 and 9:00 on the electronic timepiece  1 ,  FIG. 4  is a section view through a line between 12:00 and 6:00 on the electronic timepiece  1 ,  FIG. 5  is a plan view showing main parts of the electronic timepiece  1 , and  FIG. 6  is a partially exploded oblique view of the electronic timepiece  1 . 
     The electronic timepiece  1  has an external case  30 , crystal  33 , and back cover  34 . The external case  30  includes a ceramic bezel  32  affixed to a cylindrical metal case member  31 . A round dial  11  is held inside the inside circumference of the bezel  32  by means of a plastic, ring-shaped dial ring  35 . 
     Disposed around the center of the dial  11  in the side of the external case  30  are a button A  36 , a button B  37 , and a crown  38 . 
     As shown in  FIG. 3  and  FIG. 4 , of the two main openings in the case member  31 , the opening on the face side is covered by the crystal  33  held by the bezel  32 , and the opening on the back side is covered by the metal back cover  34 . Note that the external case may be a single piece combining both the case member and back cover. 
     As shown in  FIG. 6 , the dial ring  35  attached to the inside circumference of the bezel  32 , the optically transparent dial  11 , a solar cell  135 , a movement  2 , a ring antenna  110 , and a bar antenna  150  are disposed inside the external case  30 . 
     As shown in  FIG. 3  and  FIG. 4 , the movement  2  includes a main plate  125 , a drive mechanism  140  supported by the main plate  125 , a circuit board  120 , a storage battery  130 , and hands  21 - 24  and a date indicator (date indicator)  20  that are driven by the drive mechanism  140 . Hands  21  to  23  are a second hand  21 , minute hand  22 , and hour hand  23  that turn on an arbor  25  disposed through the dial  11 . Hand  24  is a hand that turns on a separate pivot  26  that passes through the dial  11 . 
     The arbor  25  is disposed in the plane center of the dial  11 , and pivot  26  is disposed on the 6:00 side of the arbor  25 . 
     The drive mechanism  140  is disposed to the main plate  125 , and is covered by a circuit board  120  from the back side. The drive mechanism  140  includes a stepper motor and wheel train, and drives the hands by the stepper motor rotationally driving the pivots through the wheel train. 
     As shown in  FIG. 5 , the drive mechanism  140  more specifically includes first to fifth drive mechanisms. The first drive mechanism includes a first wheel train (not shown in the figure) and a first stepper motor  141  that drives the hour hand  23 . The second drive mechanism includes a second wheel train (not shown in the figure) and a second stepper motor  142  that drives the minute hand  22 . The third drive mechanism includes a third wheel train (not shown in the figure) and third stepper motor  143  that drives the secondhand  21 . The fourth drive mechanism includes a fourth wheel train (not shown in the figure) and a fourth stepper motor  144  that drives hand  24 . The fifth drive mechanism includes a fifth wheel train (not shown in the figure) and fifth stepper motor  145  that drives the date indicator  20 . Because this embodiment uses the ring antenna  110  as the antenna for receiving satellite signals, there is no need to provide space for a satellite signal antenna inside the movement  2 , and more stepper motors can be included. As a result, the hands  21 - 24  and date indicator  20  can be independently driven, and the movement can be driven more quickly when fast-forwarding the hands, for example. 
     Note that the bar antenna  150  is disposed at the 9:00 position of the movement  2 , and a lithium ion battery or other type of storage battery  130  is disposed to the 12:00 position. The pivot  26 , hand  24 , the fourth stepper motor  144  and fourth wheel train that drive the hand  24 , and the fifth stepper motor  145  and fifth wheel train that drive the date indicator  20 , are disposed at the 6:00 position of the movement  2 . Space for the storage battery  130  therefore cannot be created at 6:00 in the movement  2 . The storage battery  130  is therefore disposed to the 12:00 position of the movement  2  where space can be easily created in the electronic timepiece  1  according to this embodiment. More specifically, the diameter of the storage battery  130  is smaller than the radius of the dial  11 , and can fit between the plane center of the dial  11  where the arbor  25  is located, and the outside edge of the dial  11  at 12:00. The storage battery  130  is further disposed between the  125  and the back cover  34  in the thickness direction of the electronic timepiece  1 . The storage battery  130  is charged by power produced by the solar cell  135  as described below. 
     The dial ring  35  is shaped like a ring when seen in plan view, and is conically shaped when seen in section. A donut-shaped space is created by the dial ring  35  and the inside circumference surface of the bezel  32 , the ring-shaped antenna  110  for receiving satellite signals is housed in this space. 
     Ring Antenna 
     The ring antenna  110  is disposed around the outside circumference of the dial  11  and is covered by the dial ring  35 . The inside circumference surface of the dial ring  35  is tapered to improve the visibility of the dial  11 , and the inside circumference surface of the ring antenna  110  is similarly tapered. 
     The ring antenna  110  has an annular antenna base, and an antenna element is formed on the surface of the antenna base. The antenna element is an electrode pattern embodied by electroless plating, a flexible printed circuit (FPC), or a silver paste positioning process, for example. 
     The antenna base is made of plastic due to its complex shape. In this case, a dielectric material that can be used at high frequencies, such as titanium oxide or ceramic, is mixed with the plastic to increase the dielectric constant. The frequency of satellite signals (GPS satellite signals) that are transmitted from the GPS satellites S is 1575.42 MHz, and one wavelength is approximately 19 cm. Because an antenna length of approximately 1.0 to 1.2 times the wavelength is required to receive circularly polarized GPS satellite signals, a loop antenna of approximately 19 to 24 cm is required to receive GPS satellite signals, which is difficult to fit inside a wristwatch. 
     This embodiment therefore uses the wavelength shortening effect of dielectric constant ∈r to enable receiving GPS satellite signals with a wristwatch ring antenna  110  approximately 3 cm in diameter. When an antenna base with dielectric constant ∈r is used, the wavelength shortening ratio is generally (∈r) −1/2 . In other words, by using a dielectric of dielectric constant ∈r, the wavelength of signals received by the ring antenna  110  can be shortened, and a smaller ring antenna  110  can be used. To achieve the optimal wavelength shortening effect for receiving GPS satellite signals, the dielectric constant of the antenna base is ideally approximately 6 to 15. 
     To avoid interfering with GPS signal reception, the ring antenna  110  is covered by an ABS or other type of plastic dial ring  35 , and markers for indicating the time are printed on the surface of the dial ring  35 . 
     Because the outside circumference side of the ring antenna  110  is covered by the ceramic bezel  32  and the face side of the bezel  32  is covered by the crystal  33 , there are no metal parts obstructing RF signals on the face side of the ring antenna  110 . As a result, good reception performance can be assured in the ring antenna  110  used to receive satellite signals. 
     The ring antenna  110  is connected to the circuit board  120  through an antenna connection pin  115  on the 6:00 side of the dial  11 . The antenna connection pin  115  is a spring-loaded feed pin, and as shown in  FIG. 6  is inserted to a through-hole formed in the movement  2 , and more specifically in the main plate bridge ring  126  as shown in  FIG. 4 . Product assembly is therefore improved because there is no need to solder or screw the ring antenna  110  and circuit board  120  together. 
     Bar Antenna 
     As shown in  FIG. 3 , the bar antenna  150  for receiving long-wave standard time signals is a bar antenna comprising an antenna core  151  and a coil  152  wound around the antenna core  151 . 
     The antenna core  151  is made by, for example, stacking approximately 10 to 30 layers of an amorphous cobalt foil as a magnetic foil material on the antenna core  151  in the thickness direction of the electronic timepiece  1 , and stabilizing the magnetic characteristics by annealing or other heat process. 
     The antenna core  151  has the coil winding where the coil  152  is wound, and leads extending from the opposite lengthwise ends of the coil winding. The leads are tapered and narrow from the base at the coil winding end to the distal ends of the antenna core  151 . 
     Note that the antenna core  151  is not limited to a stacked amorphous foil configuration, and may be a soft magnetic metal ribbon. Further alternatively, while performance drops, a low cost ferrite antenna core  151  that can be molded with a die and heat treated may be used. 
     To receive long-wave standard time signals (40-77.5 kHz), the coil  152  wound to the winding part of the antenna core  151  requires inductance of approximately 20-100 mH. As a result, the coil  152  is made by winding several hundred turns of approximately 50 μm diameter polyurethane enameled copper wire. 
     A bar antenna  150  thus configured is disposed at 9:00 on the dial  11 , and is screwed to the main plate  125 . The coil  152  of the bar antenna  150  is conductive to the circuit board  120 . 
     Circuit Board 
     The circuit board  120  is populated with a GPS receiver (GPS module)  500 , standard time signal receiver circuit (standard time signal module)  400 , and a controller (CPU)  61 . 
     A circuit cover  122  is disposed below the circuit board  120 . A magnetic shield not shown may be disposed between the circuit board  120  and circuit cover  122  to improve magnetic resistance. 
     Display Mechanism of the Electronic Timepiece 
     The hands  21 ,  22 ,  23  are disposed to an arbor  25  that passes through the front and back of the dial  11  in the plane center. Note that the center arbor  25  comprises three pivots (rotational pivots) to which the hands  21 ,  22 ,  23  are attached. 
     A scale of 60 minute markers is formed on the inside circumference side of the dial ring  35  around the outside edge of the dial  11 . Using these markers, hand  21  indicates the second of the first time (the local time, such as the current local time when travelling abroad), hand  22  indicates the minute of the first time, and hand  23  indicates the hour of the first time. 
     The dial  11  also has markers used to indicate the reception result. More specifically, the letters RC indicating that standard time signal reception was successful are provided at the 8 second position of the dial  11 ; the symbol 4+ indicating that the positioning reception process was successful is provided at the 52 second position; and a 1 indicating that the timekeeping reception process was successful is provided at the 38 second position. The letter N indicating that the standard time signal reception process, positioning reception process, or the timekeeping reception process failed is provided at the 22 second position of the dial  11 . 
     Note that the symbols and positions of these markers are not limited to the example shown in  FIG. 2 , and any markers enabling the user to know the reception mode may be used. 
     The subdial  12  (small hand indicator) is disposed at 6:00 on the dial  11 . The letters S, M, T, W, T, F, S denoting the days of the week are provided on the right half of the subdial  12 . The symbols DST indicating that daylight saving time is in effect, and a solid dot indicating that daylight saving time is not in effect, are provided around the 8:00 position (the 8:00 position of the hand  24  relative to the pivot  26 ) on the left side of the subdial  12 . A sickle-shaped power reserve indicator between E (empty) and F (full) markers is also provided on the left side of the subdial  12 . The information display comprising the subdial  12  and hand  24  (small hand) can indicate information including the timekeeping mode, day of the week, remaining battery capacity. 
     If the user pushes the button A  36  for less than 3 seconds, for example, in the operation to display the previous reception result, the second hand  21  moves rapidly and stops at the appropriate position, that is, RC, 4+, 1, or N. By checking the position indicated by the second hand  21 , the user can know the content of the previous reception result and whether reception was successful or failed. 
     Simultaneously, the hand  24  indicates the power reserve left in the storage battery  130 . More specifically, the hand  24  points to F if the storage battery  130  is still near full capacity, and points to E if the battery is low. If the charge of the storage battery  130  is at an intermediate level, the hand  24  points to a position on the scale corresponding to the battery capacity. The hand  24  points to a position in the black range near the F marker when the voltage level of the battery is sufficient to run the positioning reception process (a level at or above a second threshold described below). 
     If the user pushes button A  36  for 3 or more and less than 6 seconds to manually start the reception process in the timekeeping mode, the second hand  21  jumps to the 1 marker. If the user pushes button A  36  for 6 seconds or more to start reception in the positioning mode, the second hand  21  jumps to the 4+ marker. The user can thus know the reception mode and that reception is in progress. 
     Note that this embodiment does not have a manual reception mode for standard time signals, but if such a mode is provided, the user can know that standard time signal reception was manually started by the second hand  21  pointing to the RC marker. 
     This embodiment may also be configured so that the second hand  21  does not move to the RC marker, 1 marker, or 4+ marker indicating the corresponding reception mode when the reception process starts automatically. This is because the automated reception process often executes when the electronic timepiece  1  is set aside and the user does not look at the second hand  21 . However, the user can also know the reception mode and progress during the automated reception process if the second hand  21  moves to the RC marker, 1 marker, or 4+ marker indicating the reception mode and that reception is in progress when reception starts automatically. 
     While reception starts manually in the positioning mode when the user pushes button A  36  for 6 seconds or more, this embodiment may also be configured to execute a leap second reception mode if the user continues pushing the button A  36  for a total of 10 seconds or more. 
     The time information received from GPS satellites is time information based on an atomic clock, and does not account for leap seconds. As a result, to correct the internal time of the electronic timepiece  1 , UTC (Coordinated Universal Time) must be calculated by adding the current leap second value to the received time information. The current leap second information is stored on subframe  4 , page 18 of the satellite signal, and is transmitted every 12.5 minutes. To acquire the leap second information in the leap second reception mode, reception must continue for a maximum 12.5 minutes. As a result, an LP marker denoting the leap second reception mode is preferably provided on the dial  11 , and the second hand  21  points to this LP marker when the leap second reception mode is running. LP is a symbol denoting LeaP second, and may be provided between the 4+ marker and RC marker, or the LP marker may be provided instead of the RC marker. 
     If the operating mode can be switched between the timekeeping mode, positioning mode, and leap second reception mode according to how long the user pushes button A  36 , the reception mode can be changed by the same operation of simply pushing button A  36 . Leap second information is infrequently received, normally only once every several years. As a result, if a special operation must be performed to execute the leap second reception mode, remembering the necessary operation can be difficult. However, if the leap second reception mode is set based on how long the button A  36  is pushed, it is only necessary to change how long button A  36  is pushed, and usability can be greatly improved. Furthermore, because the second hand  21  indicates the selected reception mode, the user can reliably select the desired reception mode, and usability can be further improved. 
     The date window  15  is a rectangular opening in the dial  11  through which the date (numbers) printed on the date indicator  20  can be seen. The date indicator  20  displays the day value of the current date at the first time with the number that is visible through the date window  15 . 
     Time difference information indicating the time difference to UTC (Coordinated Universal Time) is denoted by numbers around the inside circumference of the dial ring  35 . Time difference information may also be indicated by numbers and non-numeric symbols. 
     City information denoting the name of a city located in the time zone that uses the standard time corresponding to the time difference indicated on the dial ring  35  may also be expressed beside the time difference information on the bezel  32  surrounding the dial ring  35 . The city information is a three letter code abbreviating the name of the city with three alphabetic letters, such as TYO for Tokyo. 
     A solar cell  135 , which is a photovoltaic power generator, is disposed between the dial  11  and a main plate  125 . 
     As shown in  FIG. 6 , the solar cell  135  is a round flat solar panel having four solar cells  135 A (photovoltaic devices) that convert light energy to electrical energy (power) connected in series. The solar cell  135  is substantially the same size as the dial  11 . 
     Note that as described below, the solar cell  135  is also used to determine if the electronic timepiece  1  is outdoors or not by detecting sunlight as described below. 
     Through-holes through which the center arbor  25  of the hands  21 ,  22 ,  23  and the pivot  26  of hand  24  pass, and an aperture  135 B and the date window  15  through which the date indicator  20  is exposed, are formed in the dial  11  and solar cell  135 . 
     Circuit Configuration of the Electronic Timepiece 
       FIG. 7  shows the basic circuit configuration of the electronic timepiece  1 . 
     The main components of the electronic timepiece  1  include a standard time signal receiver  4  that receives long-wave standard time signal and acquires time information; a satellite signal receiver  5  that receives satellite signals and acquires time information; a display controller  6 ; and a power supply unit  7 . 
     As shown in  FIG. 8 , long-wave standard time signals can only be received in specific areas of the world. More specifically, JJY40 and JJY60 can be received in areas centered on Japan; BPC can be received in an area centered on China, WWVB in an area centered on the United States, MSF in an area centered on Great Britain, and DVF77 in an area centered on Germany. 
     GPS satellite signals, however, can be received in an area significantly larger than the reception areas for long-wave standard time signals, that is, anywhere in the world. 
     Information related to the reception areas where long-wave standard time signals can be received is stored in the storage  67  described below. 
     Time Code Format of Long-Wave Standard Time Signals 
     The time information (time code) of a long-wave standard time signal is configured based on the time information format (time code format) specific to each country. 
     For example, with the time code format of the JJY signal transmitted in Japan as shown in  FIG. 9 , one signal is transmitted each second, and it takes 60 seconds to transmit one record (one frame). In other words, one frame comprises 60 bits of data. The data fields contained in this time code format include the minute and hour of the current time, the cumulative number of days since January 1 of the current year, the year (denoted by the last two digits of the Gregorian calendar year), the day of the week, and the leap seconds. The value for each field is determined by combining the value assigned to each second (each bit), and the combination is determined from the type of signal. A parity bit PA 1  corresponding to the hour, and a parity bit PA 2  corresponding to the minute, are inserted between the bit train of the cumulative number of days and the bit train for the year. Note that M in  FIG. 9  denotes the minute (0 second of each minute), and P 1  to P 5  are position marker signals, the positions of which are predefined. 
     The signal denoting a 1 in each field is a signal with a pulse width of approximately 0.5 second, signals denoting a 0 are signals with a pulse width of approximately 0.8 second, the P signals denoting the markers are signals with a pulse width of approximately 0.2 second. 
     The time code format of the standard time signal and the pulse widths (duty) of the various signals are set according to the type of long-wave standard time signal. 
     Navigation Data Message of the Satellite Signal 
     The navigation data message contained in the satellite signals sent from a GPS satellite and carrying the acquired information described above is described next. Note that the navigation data message is modulated at 50 bps onto the satellite signal carrier. 
       FIG. 10A  to  FIG. 10C  describe the format of the navigation data message. 
     As shown in  FIG. 10A , a navigation data message is composed of main frames each containing 1500 bits. Each main frame is divided into five subframes  1  to  5  of 300 bits each. The data in one subframe is transmitted in 6 seconds from each GPS satellite. It therefore takes 30 seconds for the data in one main frame to be transmitted from a GPS satellite. 
     Subframe  1  contains satellite correction data including week number data and SV health information. The week number identifies the week of the current GPS time information. More specifically, GPS time started at 00:00:00 on Jan. 6, 1980 in UTC, and the week number of the week that started that day is week number 0. The week number is updated every week. The SV health information is a code indicating satellite errors, and this code can be used to prevent using signals transmitted from satellites where there is an error. 
     Because subframes  1  to  3  in each set of five subframes contains information specific to a particular satellite, the same content is repeated during every transmission. More specifically, subframes  1  to  3  contain clock correction data and orbit information (ephemeris) specific to the transmitting satellite. Subframes  4  and  5 , however, contain orbit information for all satellites (almanac data) and ionospheric correction information, which because of the large amount of information is divided into page units and stored in subframes  4  and  5  over pages 1 to 25. Because 25 frames are required to transmit the content of all pages, 12 minutes 30 seconds is required to receive all of the information in the navigation data message. 
     Each of subframes  1  to  5  starts with a telemetry (TLM) word storing 30 bits of telemetry data followed by a HOW word (handover word) storing 30 bits of handover data. 
     Therefore, while the TLM and HOW words are transmitted at 6-second intervals from the GPS satellites, the week number data and other satellite correction data, ephemeris, and almanac data are transmitted at 30-second intervals. 
     As shown in  FIG. 10B , the TLM word contains a preamble, a TLM message and reserved bits, and parity data. 
     As shown in  FIG. 10C , the HOW word contains GPS time information called the TOW or Time of Week (also called the Z count). The Z count denotes in seconds the time passed since 00:00 of Sunday each week, and is reset to 0 at 00:00 Sunday the next week. More specifically, the Z count denotes the time passed from the beginning of each week in seconds. The Z count denotes the GPS time at which the first bit of the next subframe data is transmitted. 
     For example, the Z count transmitted in subframe  1  denotes the GPS time that the first bit in subframe  2  is transmitted. The HOW word also contains 3 bits of data denoting the subframe ID (ID code). More specifically, the HOW words of subframes  1  to  5  shown in  FIG. 10A  contain the ID codes 001, 010, 011, 100, and 101, respectively. 
     Standard Time Signal Receiver 
     As shown in  FIG. 7 , the standard time signal receiver  4  includes the bar antenna  150  and standard time signal receiver circuit  400 . The bar antenna  150  receives long-wave standard time signals (referred to below as a standard time signal), and outputs the received standard time signal to the standard time signal receiver circuit  400 . The standard time signal receiver circuit  400  demodulates the standard time signal received by the bar antenna  150 , and outputs the demodulated signal as a TCO (Time Code Output) signal to the controller  61  of the display controller  6 . 
     The standard time signal receiver circuit  400  includes a tuning circuit  411 , amplifier  412 , mixer  413 , an IF (intermediate frequency) amplifier  414  with a crystal filter, an envelope detection circuit  415 , an AGC (Auto Gain Control) circuit  416 , a binarization circuit  417 , a PLL (phase locked loop)  418 , and a VCO (Voltage Controlled Oscillator)  419 . The standard time signal receiver circuit  400  is a common circuit for receiving standard time signals. 
     The tuning circuit  411  comprises a capacitor, and a parallel resonance circuit is embodied by the tuning circuit  411  and bar antenna  150 . This tuning circuit  411  is configured so that JJY (JJY40 and JJY60), WWVB, DCF77, MSF, and BPC standard time signals can be selectively received. 
     Note that as described further below, when positioning information (latitude and longitude) for the electronic timepiece  1  is acquired by the satellite signal receiver  5 , the controller  61  outputs a selection signal for the receiver station based on the positioning information to the standard time signal receiver circuit  400 . The tuning circuit  411  of the standard time signal receiver circuit  400  then automatically selects the receiver station based on the control signal. 
     When positioning information for the electronic timepiece  1  has not been acquired by the satellite signal receiver  5 , the appropriate receiver station can be selected by the user manipulating the crown  38  or other operating member to select the time zone (time difference). 
     The amplifier  412  adjusts the gain according to the signal (AGC voltage) input from the AGC circuit  416 , and amplifies the reception signal input from the tuning circuit  411  to a specific amplitude, and inputs the amplified signal to the mixer  413 . 
     The mixer  413  mixes the reception signal with a signal from the VCO  419 , and down-converts to an intermediate frequency (IF). 
     The IF amplifier  414  further amplifies the reception signal input from the mixer  413 , and outputs to the envelope detection circuit  415 . 
     The envelope detection circuit  415  comprises a rectifier not shown and a low-pass filter (LPF) not shown, rectifies and filters the input reception signal, and outputs the filtered envelope signal to the AGC circuit  416  and binarization circuit  417 . 
     Based on the envelope signal input from the envelope detection circuit  415 , the AGC circuit  416  outputs a signal determining the gain used by the amplifier  412  to amplify the reception signal. 
     The binarization circuit  417  compares the envelope signal input from the envelope detection circuit  415  with a reference signal (threshold), and outputs a binarized signal, that is, a TCO signal. 
     Satellite Signal Receiver 
     The satellite signal receiver  5  includes the ring antenna  110 , a filter (SAW)  111 , and the GPS receiver  500  (reception module). 
     The SAW filter  111  is a bandpass filter that passes signals in the 1.5 GHz waveband. A LNA (low noise amplifier) may also be disposed between the ring antenna  110  and the filter  111  to improve reception sensitivity. Note also that the filter  111  may be embedded in the GPS receiver  500 . 
     The GPS receiver  500  processes satellite signals passed through the filter  111 , and includes an RF (radio frequency) circuit  510  and a baseband circuit  520 . 
     The RF circuit  510  includes a PLL circuit  511 , a VCO (voltage controlled oscillator)  512 , a LNA (low noise amplifier)  513 , a mixer  514 , an IF amplifier  515 , an IF filter  516 , and an A/D converter  517 . 
     A satellite signal passed by the filter  111  is amplified by the LNA  513 , then mixed by the mixer  514  with the 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 circuit  520  includes 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)  530  and flash memory  540  are also connected to the baseband circuit  520 . 
     A digital signal is input from the A/D converter  517  of the RF circuit  510  to the baseband circuit  520 , which acquires satellite time information and navigation information by a correlation process and location computing process. 
     Note that the clock signal for the PLL circuit  511  is generated by the TCXO  530 . 
     A time difference (time zone) database relating location information (latitude and longitude) to time difference (time zone) information is stored in flash memory  540 . Therefore, if the location can be calculated by receiving satellite signals, the time difference (time zone) at the received location can be detected and set based on the latitude and longitude data and the time difference database. Note that an EEPROM (electrically erasable programmable read-only memory) device may be used instead of flash memory  540 . 
     Note that while the time zone database is stored in the flash memory  540  of the GPS receiver  500  in this embodiment, nonvolatile memory such as EEPROM or flash memory may be provided in the controller  61  of the display controller  6 , and the time difference database stored in this nonvolatile memory device. 
     Display Controller 
     The display controller  6  includes a controller (CPU)  61 , a drive circuit  62  that drives the hands  21 - 24 , a crystal oscillator  63 , a time display, and an information display. 
     The controller  61  includes a RTC  66  and storage  67 . 
     The RTC  66  keeps the internal time using a reference signal output from a crystal oscillator  63 . 
     The storage  67  stores the satellite time information and positioning information output from the GPS receiver  500 , and the TCO (time information of the standard time signal) output from the standard time signal receiver circuit  400 . 
     The controller  61  switches between the standard time signal receiver  4  and satellite signal receiver  5  by outputting control signals to the standard time signal receiver  4  and satellite signal receiver  5 . GPS satellite signals have a higher frequency than standard time signals at approximately 1.5 GHz, and the strength of the reception signal is approximately 1/100. As a result, the GPS satellite signal reception process of the satellite signal receiver  5  requires approximately 500 times as much power as the standard time signal reception process of the standard time signal receiver  4 . The controller  61  therefore switches between the standard time signal receiver  4  and satellite signal receiver  5  instead of driving them simultaneously. 
     By having a standard time signal receiver  4 , satellite signal receiver  5 , and display controller  6  as described above, the electronic timepiece  1  according to this embodiment can automatically correct the time information based on the standard time signal received from a standard time signal transmitter R, and can automatically correct the displayed time based on the satellite signals from the GPS satellites S. 
     Power Supply Unit 
     The power supply unit  7  includes the solar cell  135 , a charging control circuit  71 , the storage battery  130 , a first regulator  72 , a second regulator  73 , and a voltage detection circuit  74 . 
     When light is incident and the solar cell  135  produces power, the power obtained by photovoltaic generation is passed by the charging control circuit  71  to the storage battery  130  to charge the storage battery  130 . The solar cell  135  therefore embodies the power generator. 
     The storage battery  130  supplies drive power through the first regulator  72  to the display controller  6  and the standard time signal receiver circuit  400 , and supplies power through the second regulator  73  to the GPS receiver  500 . The storage battery  130  therefore embodies a power supply that supplies drive power. 
     The voltage detection circuit  74  monitors the output voltage of the storage battery  130 , and outputs to the controller  61 . The voltage detection circuit  74  therefore embodies a reserve power detector that detects how much power remains in the storage battery  130  embodying the power supply. Because the battery voltage detected by the voltage detection circuit  74  is input to the controller  61 , the controller  61  can know the voltage of the storage battery  130  and control the reception process appropriately. 
     When the solar cell  135  and storage battery  130  are disconnected as controlled by the controller  61 , the charging control circuit  71  can control detecting the voltage of the solar cell  135  by the voltage detection circuit  74 . In this event, the voltage detection circuit  74  can detect the output voltage (power output) of the solar cell  135  without affecting the voltage of the storage battery  130 . The voltage detection circuit  74  therefore embodies a power generation detector that detects the power output of the solar cell  135 , and inputs the detected power output to the controller  61 . As a result, the controller  61  can determine whether or not the electronic timepiece  1  is outdoors based on the power output of the solar cell  135 . 
     Controller Configuration 
     The configuration of the controller  61  is described next with reference to  FIG. 11 .  FIG. 11  illustrates the function blocks that are embodied by a program executed by the controller  61 . 
     The controller  61  includes a time information corrector  610 , display controller  620 , voltage detection controller  630 , and a reception controller  640 . 
     The time information corrector  610  corrects the internal time information using the time information received by the standard time signal receiver  4  or satellite signal receiver  5 . 
     In the normal operating mode, the display controller  620  controls the drive circuit  62  based on the internal time information to display the time (hour, minute, second) with the hands  21  to  23 . The display controller  620  also controls the drive circuit  62  based on the internal time information to indicate the day of the week (Sunday to Saturday) with hand  24 . The display controller  620  also controls the information indicated by the hands  21 - 24  appropriately to the reception control state. 
     The voltage detection controller  630  operates the voltage detection circuit  74  to detect the voltage, that is, the remaining battery capacity, of the storage battery  130 , and the power output of the solar cell  135 . The voltage detection controller  630  operates the voltage detection circuit  74  and detects the battery voltage at a specific time interval. The voltage detection controller  630  also controls operation of the charging control circuit  71 . 
     Reception Controller 
     The reception controller  640  includes a reception mode selector  641 , a satellite signal reception controller  642 , a standard time signal reception controller  645 , and a reception result detector  646 . The satellite signal reception controller  642  includes a timekeeping reception controller  643 , and a positioning reception controller  644 . 
     The reception mode selector  641  determines if the button A  36  was operated to start reception, or if a predetermined automatic reception condition was met, and selects the satellite signal reception mode (timekeeping mode or positioning mode) or the standard time signal reception mode. The reception mode selector  641  selects the timekeeping mode if button A  36  is pressed for a first specific time (such as 3 or more and less than 6 seconds), and selects the positioning mode if button A  36  is pressed for a second specific time (such as 6 seconds or more). If the voltage detection circuit  74  detects that the electronic timepiece  1  is outdoors and an automatic reception condition is met, the reception mode selector  641  normally selects the timekeeping mode, and selects the positioning mode only once after the reception-off mode of the electronic timepiece  1  is cancelled. 
     The satellite signal reception controller  642  is operated when the satellite signal reception mode is selected by the reception mode selector  641 . 
     If the timekeeping mode is selected, the satellite signal reception controller  642  operates the timekeeping reception controller  643 , and the timekeeping reception controller  643  controls the satellite signal receiver  5  to execute the timekeeping reception process. 
     If the positioning mode is selected, the satellite signal reception controller  642  operates the positioning reception controller  644 , and the positioning reception controller  644  controls the satellite signal receiver  5  to execute the positioning reception process. 
     The standard time signal reception controller  645  is operated when the standard time signal reception mode is selected by the reception mode selector  641 . The standard time signal reception controller  645  controls the standard time signal receiver  4  to execute the standard time signal reception process. 
     The reception result determiner  646  determines if the timekeeping reception process of the timekeeping reception controller  643 , the positioning reception process of the positioning reception controller  644 , or the standard time signal reception process of the standard time signal reception controller  645  was successful. 
     For example, in the timekeeping reception process, the reception result determiner  646  compares the time information (Z count) acquired from the received satellite signal and the time data of the RTC  66  match. If the difference therebetween is great, the reception result determiner  646  may compare the Z count with the Z count received in the next subframe to prevent correction errors, and if multiple satellites are locked onto, the reception result determiner  646  may compare the Z counts from the plural satellites to determine if the acquired time data matches. If the reception result determiner  646  determines the times match, the time information corrector  610  corrects the time. 
     Automatic Reception Process 
     The automatic reception process, which is a reception process executed when a predetermined automatic reception condition is met, in this embodiment is described next with reference to  FIG. 12  to  FIG. 16 . 
     When the electronic timepiece  1  is not set to a mode that blocks executing the automatic reception process, such as an airplane mode, the controller  61  executes the process shown in  FIG. 12 . 
     The relationship between battery voltage and discharge capacity (remaining battery capacity, power reserve) is shown in  FIG. 16 . This embodiment uses a lithium ion battery as the storage battery  130 , and  FIG. 16  shows the discharge voltage characteristic thereof. As will be understood from the relationship between the battery voltage and the discharge capacity shown in the graph in  FIG. 16 , the power reserve (storage capacity) of the storage battery  130  can be known by measuring the battery voltage of the storage battery  130 . 
     The voltage detection circuit  74  operates at a specific interval, such as 60 seconds, as controlled by the voltage detection controller  630 . Because the voltage detection circuit  74  detects the battery voltage every 60 seconds, the controller  61  always knows the remaining capacity of the storage battery  130 . 
     The voltage detection controller  630  sets the battery voltage of the storage battery  130  at which the controller  61  may shut down if the standard time signal reception process, which consumes less current than the GPS satellite signal reception process, is executed as the prohibit-reception voltage. The voltage detection controller  630  also sets the voltage at which the controller  61  will not shut down if the timekeeping reception process of GPS satellite signals, which consumes more current than the standard time signal reception process, is executed as a first threshold, and sets the voltage at which the controller  61  will not shut down if the positioning reception process, which consumes more current than the timekeeping reception process, is executed as a second threshold. 
     The prohibit-reception voltage is set to 3.4 V, for example, for a storage battery  130  with a discharge characteristic as shown in  FIG. 16 . In addition, the first threshold is 3.5 V, and the second threshold is 3.6 V. In the graph in  FIG. 8 , the discharge capacity is approximately 80% of full capacity when the battery voltage is 3.6 V, and approximately 99% of full capacity when the battery voltage is 3.4 V. The prohibit-reception voltage and the first and second threshold voltages may be set based on the discharge characteristic of the storage battery  130 . 
     Note that this embodiment detects the power reserve of the storage battery  130  by detecting the battery voltage of the storage battery  130 , but the remaining battery capacity may be detected more accurately by adding a means of detecting the charge/discharge current of the storage battery  130 , and using a combination of the charge/discharge current and the battery voltage to decide. 
     Referring again to  FIG. 12 , the controller  61  detects the battery voltage of the storage battery  130  every 60 seconds by means of the voltage detection circuit  74 , which is a reserve power detector, and determines if the battery voltage is greater than or equal to the previously set prohibit-reception voltage (S 1 ). 
     If the battery voltage is less than the prohibit-reception voltage and S 1  returns NO, the controller  61  starts irregular movement of the hands by the drive circuit  62  (S 2 ), and maintains a reception-prohibited state (S 3 ). This irregular movement (or BLD movement) drives the hands in a mode different from the normal timekeeping mode, such as advancing the second hand  21  in 2-second increments every two seconds, in what is also referred to as a Battery Low display (BLD) or battery life indicator function. This enables the user to know that the voltage of the storage battery  130  is low and expose the solar cell  135  to light to charge the storage battery  130 . 
     During irregular movement of the hands, the controller  61  repeats step S 1  to check the battery voltage with the voltage detection circuit  74  at a regular interval, such as a 1-second interval. The controller  61  then repeats the irregular movement of step S 2  and the reception-prohibited state of step S 3  until S 1  returns YES. 
     If the battery voltage is greater than or equal to than the prohibit-reception voltage and S 1  returns YES, the controller  61  determines if the current location of the electronic timepiece  1  is within a standard time signal reception area (S 4 ). More specifically, if the positioning information (latitude and longitude) acquired by the positioning reception process and information indicating standard time signal reception areas are stored in the storage  67 , and the positioning information is within any standard time signal reception area, the controller  61  returns YES in S 4 . The controller  61  also returns YES in S 4  if time zone data set by the user manipulating the crown  38 , for example, is stored in the storage  67  and this time zone data is within an standard time signal reception area. 
     If S 4  returns YES, the controller  61  determines if the internal time (current time) kept by the controller  61  is a previously set scheduled standard time signal reception time (S 5 ). The scheduled standard time signal reception time is set to a time when there is little noise, such as 2:00 a.m. Plural scheduled standard time signal reception times may also be set, such as at 2:00, 3:00, and 4:00 a.m. In this event, if the reception process fails at 2:00 a.m., the reception process repeats at 3:00 a.m., and if the reception process fails at 3:00 a.m., the reception process repeats at 4:00 a.m. 
     If the internal time has reached a scheduled standard time signal reception time, the controller  61  returns YES in S 5 . In this event, the controller  61  stops movement of the hands  21 - 24  by the drive circuit  62  (S 6 ). That standard time signal reception is in progress may be displayed in this event by stopping the second hand  21  at the RC marker at the 8-second position. 
     Next, the controller  61  starts the standard time signal reception process (S 50 ). This standard time signal reception process is described further below. 
     If the current location or the time zone data set by the user is outside a standard time signal reception area (S 4  returned NO), or if the location is within a standard time signal reception area but a scheduled reception time has not been reached (S 5  returned NO), the controller  61  determines if the standard time signal was received at the last scheduled reception time and acquisition of time information was successful, or if acquisition was not successful (S 7 ). 
     If the standard time signal was received, acquisition of time information was successful, and step S 7  returned YES, the controller  61  returns to step S 1  because there is no need to receive GPS satellite signals. As a result, if the standard time signal was received and time information acquisition was successful at the scheduled standard time signal reception time at 2:00 a.m., for example, the GPS satellite signal reception process is not executed until the scheduled standard time signal reception time the next day. Therefore, if the standard time signal is received and time information acquisition is successful at the scheduled standard time signal reception time every day, the standard time signal reception process is prioritized and the GPS satellite signal reception process is not executed. 
     However, if at the scheduled standard time signal reception time the standard time signal reception process is not executed (S 4  returns NO), or if acquisition of time information by receiving a standard time signal failed, such as if the reception process was executed but the standard time signal could not be received, or if the standard time signal was received but acquisition of time information failed, the controller  61  returns NO in S 7  and goes to step S 8 . Therefore, if daily reception of the standard time signal fails, the GPS satellite signal reception process executes if the conditions defined by steps S 8  to S 10  are satisfied. 
     If S 7  returns NO, the controller  61  determines if the internal time is from 5:00 to 21:00 (S 8 ). S 8  determines is the current time is not night (21:00 to 5:00) when the sun is not out. 
     If S 8  returns YES, the controller  61  determines if the battery voltage detected by the voltage detection circuit  74  is greater than or equal to the first threshold or the second threshold (S 9 ). That is, if the reception process is being executed by the timekeeping reception controller  643 , the controller  61  determines if the battery voltage is greater than or equal to the first threshold (S 9 ). If the reception process is being executed by the positioning reception controller  644 , the controller  61  determines if the battery voltage is greater than or equal to the second threshold (S 9 ). 
     If S 9  returns YES, the controller  61  determines if outdoor detection is successful (S 10 ). Outdoor detection determines if the solar cell  135  is exposed to sunlight. As a result, the controller  61  regularly controls the charging control circuit  71  to interrupt the charging path between the solar cell  135  and storage battery  130 , then detects the voltage of the solar cell  135  with the voltage detection circuit  74 , and detects being outdoors if the voltage of the solar cell  135  is greater than or equal to a specific voltage. 
     If NO is returned by any of steps S 8  to S 10 , the controller  61  returns to S 1 . If steps S 8  to S 10  each return YES, the controller  61  moves the second hand  21  to the 1 marker, or to the 4+ marker if the positioning mode was selected immediately after cancelling the airplane mode, to indicate that GPS satellite signals are being received (S 11 ). 
     Next, the controller  61  starts the GPS satellite signal reception process (S 20 , S 30 ). More specifically, if the internal time is between 5:00 and 21:00, that is, it is not night when the sun is not out (S 8  returns YES), the battery voltage is greater than or equal to the first threshold (3.5 V) or the second threshold (3.6 V), and outdoor detection was successful, the controller  61  normally executes the timekeeping reception process (S 20 ), and executes the positioning reception process (S 30 ) only once after the airplane mode is cancelled. 
     Timekeeping Reception Process 
     The timekeeping reception process (S 20 ) shown in  FIG. 13  is described next. The process in  FIG. 13  is executed in this embodiment when the reception mode is indicated by the second hand  21  in S 11 . 
     The timekeeping reception controller  643  starts a satellite search (S 21 ). Next, the timekeeping reception controller  643  determines if a satellite was locked onto (S 22 ). If S 22  returns NO because a satellite cannot be locked, the timekeeping reception controller  643  determines if the time passed since timekeeping reception started has reached a specific timeout time (such as 1 to 2 minutes) (S 23 ). 
     If the timeout time was passed in S 23  and operating timed out (S 23  returns YES), the timekeeping reception controller  643  stops reception (S 24 ), and the controller  61  resumes normal operation of the movement (S 25 ). 
     However, if operation did not time out in S 23  (S 23  returns NO), the timekeeping reception controller  643  continues the satellite search process of S 21 . 
     If a satellite was locked onto in S 22  (S 22  returns YES), the timekeeping reception controller  643  determines if the time data (Z count) was acquired (S 26 ). Note that if plural satellites are locked, time data may be acquired from the satellite signal with the highest signal strength (SNR), or time data may be acquired from plural satellites, the coherence of the time data checked, and the success of time data acquisition determined. 
     If S 26  returns NO, the timekeeping reception controller  643  determines if a specific timeout time (such as 30 seconds) has passed (S 27 ). 
     If S 27  returns NO, the timekeeping reception controller  643  repeats S 26 . Because the Z count can be received at a 6-second interval from a GPS satellite signal, the Z count can be received five times before operation times out if the timeout time in S 27  is set to 30 seconds. 
     If operation times out in S 27  (S 27  returns YES), the timekeeping reception controller  643  ends the reception process (S 24 ), and resumes normal operation of the movement (S 25 ). 
     However, if S 26  returns YES, the timekeeping reception controller  643  ends reception (S 28 ), and the time information corrector  610  corrects the time information based on the acquired time data (S 29 ). When the time information corrector  610  corrects the time information, the display controller  620  adjusts the time indicated by the second hand  21 , minute hand  22 , and hour hand  23  through the drive circuit  62  based on the corrected time information, and then resumes normal operation of the movement (S 25 ). 
     The timekeeping reception process executed when an automatic reception condition is met thus ends. When the timekeeping reception process ends, the controller  61  returns to S 1  in  FIG. 12  and continues the process. 
     Positioning Reception Process 
     The positioning reception process S 30  is described next with reference to  FIG. 14 . 
     When the positioning reception process S 30  starts, the display controller  620  indicates with the second hand  21  that the positioning reception process is executing (S 31 ). More specifically, the display controller  620  sets the second hand  21  to the 4+ marker at the 52-second position on the dial  11  during the positioning reception process. In addition, the positioning reception controller  644  outputs a control signal to the GPS receiver  500  to start the positioning reception process (S 31 ). 
     When starting the positioning reception process is instructed, the GPS receiver  500  (baseband circuit  520 ) starts the satellite search process (S 32 ). 
     The GPS receiver  500  determines a GPS satellite S was received in the satellite search process if the satellite signal reception level is greater than or equal to a specific level. 
     The GPS receiver  500  also determines if satellite signals were received from at least the specific number of satellites required for positioning (at least 3 and normally 4) (S 33 ). 
     If S 33  returns NO, the GPS receiver  500  determines if the timeout period for the satellite search has passed (S 34 ). The timeout time for the satellite search process is, for example, 15 seconds. 
     If S 34  returns NO, the GPS receiver  500  continues the satellite search process of S 32 . 
     If S 34  returns YES, the GPS receiver  500  ends the satellite search process (S 35 ), and the controller  61  resumes normal operation of the movement (S 36 ). This is to avoid continuing the reception process and unnecessarily consuming power from the storage battery  130  because the electronic timepiece  1  is in an environment where a GPS satellite S lock is not possible. 
     If S 33  returns YES, the GPS receiver  500  determines if satellite orbit data (ephemeris) was acquired from the locked satellite signal (S 37 ). 
     If S 37  returns YES, the GPS receiver  500  calculates the location based on the acquired satellite orbit data, and determines if the positioning calculation was completed (S 38 ). 
     If NO is returned by S 37  or S 38 , the GPS receiver  500  determines if the timeout period for the positioning calculation has passed (S 39 ). This positioning calculation timeout period is 120 seconds, for example. 
     If operation has timed out in S 39  (S 39  returns YES), the GPS receiver  500  ends the reception process (S 35 ), and the controller  61  resumes normal operation of the movement (S 36 ). 
     However, if operation has not timed out in S 39  (S 39  returns NO), the GPS receiver  500  returns to S 37  and continues the process. 
     If S 38  returns YES, the GPS receiver  500  ends the reception process (S 40 ), reads the time difference information corresponding to the location information determined from the positioning calculation, from the time difference database stored in flash memory  540 , and outputs to the controller  61  (S 41 ). 
     The time information corrector  610  of the controller  61  then corrects the time information using the time difference information output from the GPS receiver  500 , and the display controller  620  displays the corrected time with the second hand  21 , minute hand  22 , and hour hand  23  (S 42 ). Next, the controller  61  resumes normal operation of the movement (S 36 ). 
     The positioning reception process executed when an automatic reception condition is met thus ends. When the positioning reception process ends, the controller  61  returns to S 1  in  FIG. 12  and continues the process. 
     Standard Time Signal Reception Process 
     The standard time signal reception process (S 50 ) shown in  FIG. 15  is described next. 
     When the reception process starts, the controller  61  selects the reception station (type of standard time signal) (S 51 ). As described above, the reception station is selected based on the positioning information acquired in the positioning reception process, or the time zone data selected and set by the use. If the previous reception process was successful, the previous reception station is used. 
     Next, the controller  61  executes a seconds synchronization process based on the TCO signal output from the binarization circuit  417  (S 52 ). The controller  61  confirms seconds synchronization by determining if the rising edge of the input TCO signal is at a one-second interval. 
     If seconds synchronization in S 52  fails (S 52  returns NO), the controller  61  determines if reception of all stations has ended (S 53 ). If S 53  returns NO, the controller  61  returns to reception station selection in S 51 , selects a different reception station, and continues the process. Note that the “all stations” evaluated in S 53  means all standard time signals that can be received by the electronic timepiece  1  (for example, if JJY40, JJY60, WWVB, BPC, DCF77, MSF can be received, all of these signals), or only the stations that can be received based on the positioning information acquired from the positioning calculation (for example, MSF and DCF77 if the positioning information indicates London). 
     If S 53  returns YES, the controller  61  determines that a standard time signal cannot be received, ends the process (S 54 ), and resumes normal operation of the movement (S 55 ). 
     If the controller  61  determines in S 52  that seconds synchronization was successful, it acquires the marker indicating the 0 second position in the time code for frame synchronization (S 56 ). For example, in the JJY standard time signal of Japan, the point where the M marker follows the P 0  marker denotes the starting point of the time code, and frame synchronization can be confirmed by detecting these contiguous markers. 
     When these markers are acquired and frame synchronization is confirmed, the controller  61  decodes the TCO signal output from the binarization circuit  417  and acquires the time code (TC) (S 57 ). 
     Next, the controller  61  determines if a specific time (such as 5 minutes) has passed since reception started (S 58 ). If S 58  returns YES, the controller  61  determines that power would be consumed wastefully without being able to receive the standard time signal even if the reception process continues, therefore ends the reception process (S 54 ), and resumes normal operation of the movement (S 55 ). 
     If NO is returned in S 58 , the controller  61  determines if the time data is coherent (S 59 ). More specifically, the controller  61  checks the parity bit or if the time data is a time that does not exist. 
     If YES is returned in S 59 , the controller  61  determines if 3 frames of data are coherent (S 60 ). If the time data acquired from three continuous time codes are at a one minute interval, it determines the three frames are coherent. 
     The controller  61  returns to the time code acquisition process of S 57  is S 59  or S 60  returns NO. 
     If S 60  returns YES, the controller  61  ends the standard time signal reception process because the correct time code was acquired (S 61 ). Next, the controller  61  corrects the internal time based on the acquired time code (S 62 ), and then resumes normal operation of the movement (S 55 ). 
     The standard time signal reception process executed when an automatic reception condition is met thus ends. When this standard time signal reception process ends, the controller  61  returns to S 1  in  FIG. 12  and continues the process. 
     Manual Reception Process 
     In this embodiment the standard time signal reception process executes only in an automatic reception process, but the GPS reception process can also be started manually by operating button A  36 . 
     When invoked manually, the timekeeping reception process is the same as the process as shown in  FIG. 13 , and the positioning reception process is the same as shown in  FIG. 14 . The manual reception process executes in the timekeeping mode if the storage battery  130  voltage is greater than or equal to a third threshold, and executes in the positioning mode if the storage battery  130  voltage is greater than or equal to a fourth threshold. In this embodiment, however, the third threshold and fourth threshold are respectively set lower than the first threshold and second threshold. 
     More specifically, as shown in Table 1, the first threshold at which the timekeeping reception process can execute automatically is 3.5 V, and the third threshold at which it can be manually executed is 3.45 V. The second threshold at which the positioning reception process can execute automatically is 3.6 V, and the fourth threshold at which it can be manually executed is 3.55 V. Note that as described above standard time signals are set to be received only in an automatic reception mode, and the voltage at which the standard time signal reception process can execute is set to 3.4 V ore more. As a result, because neither standard time signals or GPS satellite signals can be received if the voltage is less than 3.4 V, the prohibit-reception voltage is set to 3.4 V. 
     
       
         
           
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Timekeeping 
                 Positioning 
               
               
                   
                 (using only time 
                 (also using orbit 
               
               
                 Type 
                 information) 
                 information) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Standard 
                 automatic reception 
                 prohibit-reception 
                   
               
               
                 time signal 
                 (scheduled) 
                 voltage 
               
               
                   
                   
                 &lt;(3.4 V&lt;=) 
               
               
                 GPS 
                 automatic (outdoor 
                 first threshold 
                 second threshold 
               
               
                   
                 detection) 
                 &lt;=(3.5 V&lt;=) 
                 &lt;=(3.6 V&lt;=) 
               
               
                   
                 manual 
                 third threshold 
                 fourth threshold 
               
               
                   
                   
                 &lt;=(3.45 V&lt;=) 
                 &lt;=(3.55 V&lt;=) 
               
               
                   
               
            
           
         
       
     
     The manual reception process is described next. 
     If the controller  61  detects that button A  36  was pushed for 3 or more and less than 6 seconds, it detects the battery voltage. If the battery voltage is determined to be greater than or equal to the third threshold, the controller  61  executes the timekeeping reception process shown in  FIG. 13 . If the battery voltage is less than the third threshold, the controller  61  ends the reception process. 
     If button A  36  is pushed for 6 seconds or more, the controller  61  detects the battery voltage. If the battery voltage is determined to be greater than or equal to the fourth threshold, the controller  61  executes the positioning reception process shown in  FIG. 14 . If the battery voltage is less than the fourth threshold, the controller  61  ends the reception process. 
     If the reception process is started by the manual reception operation, the reception mode is indicated with the second hand  21 , and the battery reserve is indicated with the hand  24 . Because the user can therefore be informed of the reserve power left in the storage battery  130 , can know why if the reception process does not execute, and be prevented from worrying. 
     Effect of the Embodiment 
     Because the electronic timepiece  1  has two reception units, a satellite signal receiver  5  and a standard time signal receiver  4 , for receiving two types of signals, the probability of being able to acquire time information can be improved. Furthermore, because the satellite signal receiver  5  is configured so that the satellite signal reception controller  642  only determines the automatic reception condition is met if the battery voltage is greater than or equal to a first threshold, the system can be reliably prevented from shutting down due to the battery voltage dropping as a result of the satellite signal receiver  5  operating. Because the standard time signal receiver  4  is enabled by the standard time signal reception controller  645  to operate even if the battery voltage is less than the first threshold (3.5 V), the standard time signal receiver  4  can operate if the battery voltage is less than the first threshold but is greater than or equal to the prohibit-reception voltage (3.4 V). As a result, more opportunities to operate the standard time signal receiver  4  can be created, and deviation in the kept time can be reduced. 
     The standard time signal reception controller  645  can also execute the standard time signal reception process every day at a scheduled time because the standard time signal receiver  4  operates when the kept time reaches a set reception time. Because the satellite signal reception controller  642  operates the satellite signal receiver  5  only when standard time signal reception is not successful, the satellite signal receiver  5  can be operated when operation of the standard time signal receiver  4  is prioritized but a standard time signal cannot be received. As a result, time information can be acquired by the low current consumption standard time signal receiver  4  when the electronic timepiece  1  is used in a place where a standard time signal can be received, and time information can be acquired by the satellite signal receiver  5  when in a location where a standard time signal cannot be received. Power consumption by the reception process for acquiring time information can therefore be suppressed. 
     Because the reception mode selector  641  determines based on the positioning information acquired by the positioning reception process whether or not the current location is in an area where a standard time signal can be received, and controls operation of the standard time signal receiver  4  by the standard time signal reception controller  645 , unnecessary operation of the standard time signal receiver  4  when not in an area where a standard time signal can be received can be prevented. 
     Furthermore, because the positioning reception process, which consumes more power than the timekeeping reception process, is executed only when the power reserve of the battery is greater than or equal to a second threshold, which is higher than the first threshold, battery power can be reliably prevented from dropping to the system shutdown level by the positioning reception process. Furthermore, because the first threshold can be set based on the current consumption of the timekeeping reception process, more opportunities to execute the timekeeping reception process can be created than if the first threshold is set according to the positioning reception process. 
     The satellite signal reception controller  642  operates the satellite signal receiver  5  with the timekeeping reception controller  643  if the manual timekeeping reception operation is performed with button A  36  and the reserve battery power is greater than or equal to a third threshold, and operates the satellite signal receiver  5  with the positioning reception controller  644  if the manual positioning reception operation is performed and the reserve battery power is greater than or equal to a fourth threshold. Because the third threshold and fourth threshold are lower than the first threshold and second threshold for the automated reception process, more opportunities to execute the satellite signal reception process can be created when the user starts reception manually. A drop in user convenience resulting from the reception process not executing even though the reception operation is performed can therefore be prevented. 
     Because being outdoors can be determined by the voltage detection circuit  74  detecting the power output of the solar cell  135 , whether or not the electronic timepiece  1  is outdoors where satellite signal reception is easy can be determined. The probability of satellite signal reception succeeding automatically can therefore be improved. 
     By having a hand  24  and subdial  12  for displaying the remaining battery capacity, the remaining battery capacity can be displayed when reception starts. The user can therefore know that the reception process did not execute because of a low battery. Because the user can thus know why reception failed, the user can take appropriate action to charge the battery to meet the reception condition, and user convenience can be improved. 
     The thickness of the electronic timepiece  1  can also be minimized because parts that are relatively thick, such as the ring antenna  110 , first to fifth stepper motors  141  to  145 , the bar antenna  150 , and storage battery  130  are disposed not overlapping each other in plan view. 
     Furthermore, because the timekeeping reception controller  643  executes the timekeeping reception process when the timekeeping reception operation is performed if the remaining battery capacity is less than the second threshold but is greater than or equal to the first threshold, there are more opportunities to acquire time information. The accuracy of the time displayed by the electronic timepiece  1  can therefore be improved. 
     Furthermore, because reception is prohibited if the remaining battery capacity is less than a prohibit-reception voltage, a system shutdown caused by the power supply dropping below the minimum operating voltage of the controller  61  can be reliably prevented. 
     Furthermore, because the display controller  620  indicates with the second hand  21  if positioning reception, timekeeping reception, or standard time signal reception is in progress, the user can easily check the current reception mode. 
     Because the power supply unit  7  includes a solar cell  135  and storage battery  130 , the user can know to produce power with the solar cell  135  to charge the storage battery  130  if the remaining battery capacity drops below one of the thresholds and the reception process cannot execute. The reception process can therefore be run the next time the reception operation is performed if the remaining battery capacity rises above the thresholds. 
     Other Embodiments 
     The invention is not limited to the foregoing embodiment, and can be varied in many ways without departing from the scope of the accompanying claims. 
     For example, a patch antenna may be used as the antenna for receiving satellite signals.  FIG. 17  to  FIG. 19  illustrate an electronic timepiece  1 A using a patch antenna.  FIG. 19  is a section view through line A-A in  FIG. 18 . Note that like parts in this electronic timepiece  1 A and the electronic timepiece  1  described above are identified by like reference numerals and further description thereof is omitted. 
     This electronic timepiece  1 A has second hand  21 , minute hand  22 , and hour hand  23  that turn on a center arbor  25  disposed as center hands of the dial  11 , a subdial  12  and a hand  24  that turns on a pivot  26  disposed near 3:00 on the dial  11 , and a second subdial  13  and hands  27 ,  28  that turn on an arbor  29  between 7:00 and 8:00 on the dial  11 . 
     Hands  22 , and  23  are driven by a first stepper motor  141  and indicate the minute and hour of a first time (local time). Hand  21  is driven by a second stepper motor  142  and indicates the second of the first time. Hand  24  is a mode indicator driven by the third stepper motor  143 , and as in the foregoing embodiment indicates on the subdial  12  the day of the week, remaining battery capacity, and whether or not daylight saving time is set. In this electronic timepiece  1 A, hand  24  also indicates if an airplane mode is set, and whether the GPS satellite signal reception mode is the timekeeping mode or the positioning mode. 
     The hands  27 ,  28  on the second subdial  13  are dual time hands indicating the hour and minute of a second time, and normally indicate the set home time. These hands  27 ,  28  are driven by a fourth stepper motor  144 . 
     The date window  15  through which the date indicator  20  is visible is formed between 4:00 and 5:00 on the dial  11  of the electronic timepiece  1 A. The date indicator  20  is driven by the third stepper motor  143 . More specifically, the third stepper motor  143  is used to drive both hand  24  and the date indicator  20  by driving a wheel train for the hand  24  or a wheel train for the date indicator  20  by switching the direction in which the third stepper motor  143  turns. 
     In this electronic timepiece  1 A, a patch antenna  160  is disposed between 4:00 and 5:00 on the dial  11  where the date window  15  is formed, and the storage battery  130  is disposed at 10:00 on the dial  11  on the opposite side of the arbor  25  as the patch antenna  160 . A notch is formed in the solar cell  135  where it overlaps the patch antenna  160  in plan view. As a result, satellite signal reception by the patch antenna  160  is not obstructed even if a solar cell  135  with a metal substrate is used. 
     The bar antenna  150  for receiving standard time signals is located at 12:00 on the dial  11 . A notch is not formed in the solar cell  135  where it overlaps the bar antenna  150  in plan view, but long-wave standard time signals can be received without notching the solar cell  135  if the leads of the bar antenna  150  are outside of the solar cell  135 . 
     hand  24  normally indicates the day of the week, and indicates the storage battery  130  voltage (remaining battery capacity) only when button A  36  is pushed in the foregoing embodiment, but a hand that normally indicates the capacity of the storage battery  130  may also be provided. In this event, the user can easily informed of a drop in the storage battery  130  voltage, and the user can therefore be prompted to charge the storage battery  130  with the solar cell  135 . 
     In the foregoing embodiment, the third threshold is the same voltage as the first threshold, and the fourth threshold is the same voltage as the second threshold. However, the foregoing embodiment is advantageous in that the probability of being able to execute the reception process with the manual reception operation can be improved. The first threshold and third threshold may also be set to the same value. However, the foregoing embodiment is advantageous in that the probability of being able to execute the timekeeping reception process can be improved. 
     The time display of the electronic timepiece in the foregoing examples is embodied by a dial  11  and second hand  21 , minute hand  22 , and hour hand  23 , but the invention is not so limited. The electronic timepiece may have a time display embodied by an LCD panel, for example. In this event, the driver that drives the time display is embodied by a driver that drives a liquid crystal display panel. 
     The electronic timepiece also simply needs a time display function, and the time display does not need to be a dedicated display for displaying time. Examples of such electronic timepieces include heart rate monitors worn on the user&#39;s wrist, GPS loggers that are worn on the user&#39;s wrist and monitor and log the current location while the user is jogging, and other types of wearable devices. 
     A GPS satellite S is used as an example of a positioning information satellite above, but the invention is not so limited. For example, the positioning information satellite may be a satellite used in a Global Navigation Satellite System (GNSS) such as Galileo (EU) or GLONASS (Russia). Geostationary satellites in a geostationary satellite-based augmentation system (SEAS), and quasi-zenith satellites (such as Michibiki) used in a regional navigation satellite system (RNSS) that can only be accessed in specific regions, can also be used. 
     The types of standard time signals that can be received are also not limited to the standard time signals of the five countries described above, and configurations that receive only some of these standard time signals are also conceivable. 
     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. 2015-114682, filed Jun. 5, 2015 is expressly incorporated by reference herein.