Patent Publication Number: US-8971153-B2

Title: Information display device and analog electronic timepiece

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an analog information display device and an analog electronic timepiece. 
     2. Description of the Related Art 
     A conventional display device is described, for example, in Japanese Patent Laid-Open No. 6-66963. This device can display various information items by means of combination of signs provided on a dial plate and rotatable hands. 
     Display of multiple information items on a display device is achieved by selectively displaying signs and marks provided on the dial plate in association with the respective information items, or by providing hands corresponding to the respective information items. 
     Unfortunately, a larger number of information items to be displayed cause an increase in the number of marks to be indicated on the dial plate, resulting in increased design constraints and difficulty for the user in identifying which mark is indicated. 
     To address this, another conventional technique has been used that provides a rotatable information display plate (rotary disk) under the dial plate and selectively exposes any one of the signs on the rotary disk through an aperture provided in the dial plate. This technique can allow unnecessary information to remain hidden. 
     Nevertheless, when a single rotary disk is rotated with a step motor to display multiple information items selectively, it takes time to display a particular information item owing to limitations of rotation speed. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an information display device and an analog electronic timepiece that allow for quick switching among, displayed information items without compromising readability. 
     According to a first aspect of the present invention, there is provided an information display device including: a dial plate having a display window; a rotatable date display plate provided under the dial plate, the date display plate having a plurality of dates to be selectively displayed through the display window; an information display plate provided between the dial plate and the date display plate, the information display plate including an information display portion having an information item on a top surface thereof, the information item being different from the dates; and an information display plate driver capable of moving the information display plate to any one of a predetermined first position and a second position, wherein, when the information display plate is in the first position, the information display portion does not lie just under the display window and a date of the dates in a position corresponding to the display window is displayed through the display window; and when the information display plate is in the second position, the information display portion is in a position corresponding to the display window. 
     According to a second aspect of the present invention, there is provided an information display device including: a dial plate having a display window; a rotatable first information display plate provided under the dial plate, the first information display plate having a plurality of first information items to be selectively displayed through the display window; a motor which intermittently rotates the first information display plate; a rotatable second information display plate provided between the dial plate and the first information display plate, the second information display plate including a second information display portion having a second information item on a top surface thereof; and an information display plate driver which rotates the second information display plate above the first information display plate with the motor while the first information display plate is standing still, so that the second information display portion is moved to a position corresponding to the display window. 
     According to a third aspect of the present invention, there is provided an information display device including: a dial plate having a display window; a rotatable first information display plate provided under the dial plate, the first information display plate having a plurality of first information items to be selectively displayed through the display window; a second information display plate provided between the dial plate and the first information display plate, the second information display plate including a second information display portion having a second information item on a top surface thereof; and an information display plate driver capable of moving the second information display plate to any one of a predetermined first position and a second position, wherein, when the second information display plate is in the first position, the second information display portion does not lie just under the display window and a first information item of the first information items in a position corresponding to the display window is displayed through the display window; and when the second information display plate is in the second position, the second information display portion is in a position corresponding to the display window. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       The above and other objects, advantages and features of the present invention will become more fully understood from the detailed description given hereinbelow and the appended drawings which are given by way of illustration only, and thus are not intended as a definition of the limits of the present invention, and wherein: 
         FIG. 1  is an entire view of an information display system including an analog electronic timepiece according to an embodiment of the present invention; 
         FIGS. 2A and 2B  are front views of the analog electronic timepiece; 
         FIG. 3  is a block diagram illustrating the internal configuration of the analog electronic timepiece; 
         FIGS. 4A and 4B  illustrate the configuration of a date indicator and an information display plate; 
         FIG. 5  illustrates a method of displaying information using the date indicator and the information display plate; 
         FIG. 6  is a flow chart illustrating the control procedure of a displaying process to be executed by the analog electronic timepiece; 
         FIG. 7  is a flow chart illustrating the control procedure of a receiving process invoked in the displaying process; 
         FIG. 8  is a flow chart illustrating the control procedure of a process of establishing communications; 
         FIGS. 9A and 9B  illustrate the configuration of a date indicator and an information display plate in an analog electronic timepiece according to a first modification; 
         FIG. 10  illustrates a method of displaying information using the date indicator and the information display plate in the analog electronic timepiece according to the first modification; and 
         FIG. 11  illustrates the configuration of a date indicator and an information display plate in an analog electronic timepiece according to a second modification. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be described below with reference to the accompanying drawings. 
       FIG. 1  illustrates an information display system  1  including an analog electronic timepiece  10 , which is an embodiment of an information display device according to the present invention. 
     The information display system  1  of the present embodiment includes the analog electronic timepiece  10  and a smartphone  40 , which is an external device. 
     The analog electronic timepiece  10  and the smartphone  40  can communicate with each other through near field communication. 
     Non-limiting examples of the near field communication include a Bluetooth (registered trademark) scheme. 
     The analog electronic timepiece  10  receives a notice of an incoming call or e-mail to the smartphone  40  and a notice that the call or e-mail has been checked in substantially real time through the near field communication from the smartphone  40  and then makes notification. 
       FIGS. 2A and 2B  are front views of the analog electronic timepiece  10 . 
     The analog electronic timepiece  10  includes a casing  5  that covers the both sides and bottom, a dial plate  7  (first information display plate), an hour hand  16 , and a minute hand  17 . The hour hand  16  and the minute hand  17  (i.e., a plurality of hands), which can rotate about a single rotation axis, are provided between the dial plate  7  and a timepiece crystal (not shown) that covers the front face. 
     A date indicator  18  (date display plate or first information display plate) and an information display plate  19  (second information display plate) both lie under the dial plate  7 . 
     The dial plate  7 , at its three o&#39;clock position, has an aperture  8  (display window) through which any one of the signs on the date indicator  18  and on the information display plate  19  can be selectively displayed, as illustrated in  FIGS. 2A and 2B . 
     The casing  5  includes a crown C, which can be turned by a user, at its one side. 
     The dial plate  7  has hour marks on its periphery. The hour marks are signs of one through twelve o&#39;clock and arranged every 30 degrees. 
       FIG. 3  is a block diagram illustrating the internal configuration of the analog electronic timepiece  10 . 
     The analog electronic timepiece  10  includes a central processing unit (CPU)  11  (information display plate drive controller and illumination controller), read only memory (ROM)  12 , random access memory (RAM)  13 , an operation unit  14 , a time calculating circuit  15  (time calculating unit), a step motor  22  which rotates the hour hand  16  and the minute hand  17  in an interlocked manner through a gear train mechanism  20 , a step motor  23  (motor) which rotates the date indicator  18  and the information display plate  19  in an interlocked manner through a gear train mechanism  21 , a step motor driving circuit  24  (information display plate driver) which performs step drive of the step motors  22  and  23 , an antenna AN, a Bluetooth module (wireless communication unit), a universal asynchronous receiver transmitter (UART)  26 , a vibration motor  27 , a driver  28  for the vibration motor  27 , a light emitting diode (LED)  29 , a driver  30  for the LED  29 , a piezoelectric element  31 , a driver  32  for the piezoelectric element  31 , and a bus  33  which allows signals to travel between a CPU  11  and each of the above components. 
     The CPU  11  controls the overall operation of the analog electronic timepiece  10  and executes various arithmetic processes. 
     The CPU  11  sends a control signal to the step motor driving circuit  24  on the basis of the current time calculated by the time calculating circuit  15 , thereby driving the step motor  22  to display the time by the hour hand  16  and the minute hand  17 . 
     The CPU  11  also allows the step motor  23  to be driven to display a date by the date indicator  18 . 
     The CPU  11  determines the item to be displayed, on the basis of incoming information received from the smartphone  40  via the Bluetooth module  25 . 
     The CPU  11  allows the step motor driving circuit  24  to drive the step motor  23  in accordance with the item to be displayed, which then rotates the information display plate  19  to display the item. 
     The ROM  12  stores a variety of programs to be executed by the CPU  11  and default data therein. 
     The programs stored in the ROM  12  include a program for controlling Bluetooth communications with the smartphone  40 . 
     The RAM  13  provides the CPU  11  with a working memory space to store temporary data. 
     The RAM  13  also stores flags FT and FM in a binary format that respectively indicate the reception of an incoming call signal and an incoming e-mail signal, described later. 
     The operation unit  14  includes the crown C and converts the operations of pulling, pushing, and turning the crown C into their respective electrical signals, which are then sent to the CPU  11  as input signals. 
     The time calculating circuit  15  is a counter which calculates and keeps the current time on the basis of input clock signals that have a predetermined frequency. 
     This current time is read out and indicated by the hour hand  16  and the minute hand  17 . In addition, a variety of operations are performed as a result of comparison between the current time data and the set time data associated with various functions. 
     The step motor driving circuit  24  receives a control signal including a command for driving the step motors  22  and  23  from the CPU  11  and then transmits pulses for individually driving each of the step motors  22  and  23 . 
     Each of the step motors  22  and  23  is step-driven by the drive pulses from the step motor driving circuit  24  and rotates in a forward or reverse direction by a predetermined angle (e.g., 180 degrees) in response to a voltage wave form of the drive pulses. 
     The gear train mechanisms  20  and  21  are each composed of multiple gear trains. 
     The gear train mechanism  20  adjusts the rotation angle of the step motor  22  in accordance with the gear ratio to rotate the minute hand  17  by a predetermined angle (here, one degree) per step of the step motor  22 . 
     The hour hand  16  rotates in conjunction with the minute hand  17 . The gear train mechanism  21  adjusts the rotation angle of the step motor  23  in accordance with the gear ratio to rotate the information display plate  19  by a predetermined angle. 
     When the information display plate  19  rotates within a certain angular range (i.e., a predetermined part of the rotation of the information display plate  19 ), the gear train mechanism  21  also rotates the date indicator  18  in an interlocked manner. 
     The structure of the gear train mechanism  21  will be described in detail later. 
     The Bluetooth module  25  is a control module that provides Bluetooth communications with an external device via the antenna AN. 
     Data transmitted from the CPU  11  is serial- or parallel-converted by the UART  26  and is then transmitted from the Bluetooth module  25  to an external device such as the smartphone  40 . 
     Data received from the external device via the antenna AN and the Bluetooth module  25  is serial- or parallel-converted by the UART  26  and is then output to the CPU  11 . 
     The data received by the analog electronic timepiece  10  from the smartphone  40  includes control data and predetermined data. 
     This received data includes an incoming signal indicating the reception of predetermined information by the smartphone  40  and a confirmation signal indicating that the received predetermined information has been confirmed. 
     The analog electronic timepiece  10  of the present embodiment is configured to receive incoming and confirmation signals of a call and an e-mail to the smartphone  40 . 
     The call confirmation signal indicates the completion of a response to or caller ID confirmation for every incoming call associated with incoming call signals transmitted from the smartphone  40 . 
     The e-mail confirmation signal indicates the completion of check of or sender address confirmation for every incoming e-mail associated with incoming e-mail signals transmitted from the smartphone  40 . 
     The vibration motor  27 , the LED  29 , and the piezoelectric element (e.g., PZT)  31  make notification to the user by vibrations, light, and a beep, respectively. 
     When the drivers  28 ,  30  and  32  receive control signals from the CPU  11 , the drivers  28 ,  30  and  32  convert the received signals into voltage signals for operating the vibration motor  27 , the LED  29 , and the piezoelectric element  31 , respectively, and output the resultant signals. 
     These operations may be used for alarm notification of a set time in the analog electronic timepiece  10  and may also be performed for notification of incoming signal reception. 
     The rotational mechanism of the date indicator  18  and the information display plate  19  in the analog electronic timepiece  10  of the present embodiment will now be described. 
       FIGS. 4A and 4B  illustrate the date indicator  18  and the information display plate  19  in the analog electronic timepiece  10  of the present embodiment. 
       FIG. 4A  is a schematic top view of the configuration of the date indicator  18  and the information display plate  19 . 
       FIG. 4B  is a schematic side view of this configuration taken along line A-A. 
     The date indicator  18  is an annular rotary disk and rotatable about the same rotation axis as that of the hour hand  16  and the minute hand  17 . 
     The top face of the date indicator  18  has date signs indicating the dates of one through thirty-one (first information items) arranged every 11.25 degrees on the same circumference. 
     A disk-shaped information display plate  19  having a smaller radius than that of the date indicator  18  is provided above and substantially parallel to the indicator  18 . 
     The outer circumference of the information display plate  19  and the outer circumference of the date indicator  18  stand in one position at a three-o&#39;clock position. 
     The top face of the information display plate  19  has three signs of “TEL”, “MAIL” and “LINK” (information display portion or second information display portion) arranged every 90 degrees. 
     The information display plate  19  also has a small transparent window  191  at the opposite side, i.e., at 180 degrees from “MAIL” (predetermined part). The window  191  allows one of the signs on the underlying date indicator  18  to appear therethrough. 
     Note that the information display plate  19  may also provide an opening instead of the small transparent window  191  at the same position so as to allow for direct view of the underlying signs on the date indicator  18 . 
     Alternatively, the information display plate  19  may be made of a transparent member to allow the underlying date signs on the date indicator  18  to be viewed from above through the transparent member within an angular range that does not include “TEL”, “MAIL” and “LINK”. 
     A drive wheel connection gear  211  of the gear train mechanism  21  is rotated by a predetermined angle in response to the step drive of the step motor  23 , and the information display plate  19  rotates by the same angle in conjunction with the drive wheel connection gear  211 . 
     The rotation of the drive wheel connection gear  211  only within a predetermined angular range is transmitted to a date indicator driving wheel  214  using a pin  212  and a slot  213  of a Geneva drive, which allows the date indicator driving wheel  214  to engage with an internal gear of the date indicator  18 , thereby rotating the date indicator  18 . 
     In other words, a 360-degree rotation of the information display plate  19  caused by the drive wheel connection gear  211  inside a housing  51  results in rotation of the date indicator  18  by 11.25 degrees. 
       FIG. 5  illustrates actual display of information by the date indicator  18  and the information display plate  19 . 
     In a state where the small transparent window  191  of the information display plate  19  lies just under the aperture  8 , when the pin  212  which rotates with the drive wheel connection gear  211  is received in the slot  213  which rotates with the date indicator driving wheel  214  (i.e., driven wheel), the rotation of the pin  212  is transmitted to the slot  213 . 
     As a result, during a 90-degree rotation of the drive wheel connection gear  211 , the date indicator driving wheel  214  is rotated in conjunction with the drive wheel connection gear  211 , which in turn rotates the date indicator  18 . 
     This rotation changes the currently displayed date to the next date ( FIG. 5(   a ) and  FIG. 5(   b )). 
     Furthermore, this rotation causes the information display plate  19  to rotate by 90 degrees (i.e., a predetermined part of the rotation of the second information display plate) in conjunction with the drive wheel connection gear  211 , leading to appearance of “LINK” covering the date on the date indicator  18 , through the aperture  8 . 
     When the date indicator driving wheel  214  rotates by 90 degrees, the pin  212  leaves the slot  213 . 
     The date indicator driving wheel  214  does not rotate during additional 270-degree rotation of the drive wheel connection gear  211  ( FIG. 5(   b ),  FIG. 5(   c ) and  FIG. 5(   d )). 
     Thus, this 270-degree rotation of the drive wheel connection gear  211  allows solely the information display plate  19  to rotate (i.e., the rotation except for the predetermined part of the rotation of the second information display plate). 
     Rotation by 90 degrees from the state of  FIG. 5(   b ) exposes “MAIL” ( FIG. 5(   c )). 
     Rotation by 180 degrees from the state of  FIG. 5(   b ) exposes “TEL” ( FIG. 5(   d )). 
     Rotation by 270 degrees from the state of  FIG. 5(   b ) makes one of the date signs on the date indicator  18  appear through the small transparent window  191 . 
     The date indicator  18  is not rotated during 270-degree rotation of the drive wheel connection gear  211  in the reverse direction (counterclockwise as viewed from above) from the state where the small transparent window  191  is exposed for sequentially exposing the signs “TEL”, “MAIL” and “LINK” in this order through the aperture  8 . 
     Accordingly, at the time of regular date change, the analog electronic timepiece  10  rotates the drive wheel connection gear  211  by 360 degrees in the forward direction (clockwise as viewed from above) to display the next date through the aperture  8  and the small transparent window  191 . 
     The drive wheel connection gear  211  is then rotated in the reverse direction from this position as needed within a maximum range of 270 degrees, and thereby any one of the date and the signs of “TEL”, “MAIL” and “LINK” associated with other information items can be exposed as appropriate without shifting the date indicator  18 . 
     A display operation in the analog electronic timepiece  10  according to the present embodiment will now be described. 
       FIG. 6  is a flow chart illustrating the control procedure of a displaying process to be executed by the CPU  11  of the analog electronic timepiece  10 . 
     The displaying process is invoked and executed in response to an input clock signal of 1 Hz at the time of every change of the second value. 
     In the displaying process, the CPU  11  first executes a process to obtain the time (step S 101 ). 
     The CPU  11  obtains current time data from the time calculating circuit  15  which calculates the current time on the basis of a clock signal. 
     The CPU  11  then determines whether the current time is “X0 seconds”, namely, the first digit of the second value is “0” (step S 102 ). 
     If determining that the first digit of the second value is “0”, the CPU  11  sends a control signal to the step motor driving circuit  24 , which then operates the step motor  22  to rotate the hour hand  16  and the minute hand  17  (step S 103 ). 
     The process of the CPU  11  then goes on to step S 104 . 
     If the CPU  11  determines that the first digit of the second value is not “0”, the process of the CPU  11  directly goes on to step S 104 . 
     In step S 104 , the CPU  11  determines whether it is the timing of changing the displayed date. 
     If determining that it is the timing of changing the displayed date, the CPU  11  sends a control signal to the step motor driving circuit  24 , which then operates the step motor  23  to rotate the date indicator  18  and the information display plate  19 , thereby displaying the next date (step S 105 ). 
     The process of the CPU  11  then goes on to step S 106 . 
     If the CPU  11  determines that it is not the timing of changing the displayed date, the process of the CPU  11  directly goes on to step S 106 . 
     In step S 106 , the CPU  11  determines whether a Bluetooth communication link with the smartphone  40  is established. 
     If determining that the communication link is established, the CPU  11  executes a receiving process (step S 107 ) as described below, and then finishes the displaying process. 
     If determining that the communication link is not established, the CPU  11  finishes the displaying process. 
       FIG. 7  is a flow chart illustrating the control procedure of the receiving process invoked in the displaying process. 
     In the receiving process, the CPU  11  first determines whether data is received (step S 201 ). 
     If determining that data is not received, the CPU  11  finishes the receiving process and returns the process to the displaying process. 
     If determining that data is received, the CPU  11  further determines whether the received data is an incoming signal to the smartphone  40  (step S 202 ). 
     If determining that the received data is an incoming signal, the CPU  11  further determines whether the incoming signal is an incoming call signal (step S 211 ). 
     If determining that the incoming signal is an incoming call signal, the CPU  11  sets the flag FT to “1” (step S 212 ). 
     In addition, the CPU  11  outputs a control signal to the step motor driving circuit  24  to rotate the information display plate  19  such that “TEL” on the information display plate  19  appears through the aperture  8  (step S 213 ). 
     The CPU  11  then finishes the receiving process. 
     The process of the CPU  11  then returns to the displaying process. 
     If it is determined that the received data is not an incoming call signal in the determination step S 211 , the received data is an incoming e-mail signal; thus, the CPU  11  sets the flag FM to “1” (step S 222 ). 
     The CPU  11  outputs a control signal to the step motor driving circuit  24  to rotate the information display plate  19  such that “MAIL” on the information display plate  19  appears through the aperture  8  (step S 223 ). 
     The CPU  11  then finishes the receiving process. 
     The process of the CPU  11  then returns to the displaying process. 
     If determining that the received data is not an incoming signal in the determination step S 202 , the CPU  11  further determines whether the received data is a confirmation signal (step S 203 ). 
     If determining that the received data is a confirmation signal, the CPU  11  further determines whether the confirmation signal is a call confirmation signal (step S 231 ). 
     If determining that the confirmation signal is a call confirmation signal, the CPU  11  sets the flag FT to “0” (step S 232 ). 
     The CPU  11  then determines whether the flag FM is “1” (step S 233 ). 
     If determining that the flag FM is “1”, the CPU  11  outputs a control signal to the step motor driving circuit  24 , which then operates the step motor  23  such that “MAIL” on the information display plate  19  appears through the aperture  8  (step S 234 ). 
     The CPU  11  then finishes the receiving process and returns the process to the displaying process. 
     If determining that the flag FM is not “1” in the determination step S 233 , the CPU  11  outputs a control signal to the step motor driving circuit  24 , which then operates the step motor  23  such that the small transparent window  191  of the information display plate  19  lies just under the aperture  8 , thereby causing a date sign on the date indicator  18  to appear through the aperture  8  (step S 254 ). 
     The CPU  11  then finishes the receiving process and returns the process to the displaying process. 
     If it is determined that the confirmation signal is not a call confirmation signal in the determination step S 231 , the confirmation signal is an e-mail confirmation signal; thus, the CPU  11  sets the flag FM to “0” (step S 242 ). 
     The CPU  11  then determines whether the flag FT is “1” (step S 243 ). 
     If the CPU  11  determines that the flag FT is not “1”, the process of the CPU  11  goes on to step S 254 . 
     If determining that the flag FT is “1”, the CPU  11  outputs a control signal to the step motor driving circuit  24 , which then operates the step motor  23  to rotate the information display plate  19  such that “TEL” on the information display plate  19  appears through the aperture  8  (step S 244 ). 
     The CPU  11  then finishes the receiving process and returns the process to the displaying process. 
     If determining that the received data is not a confirmation signal in the determination step S 203 , the CPU  11  executes other processes (step S 204 ), finishes the receiving process, and returns the process to the displaying process. 
       FIG. 8  illustrates a flow chart of the control procedure of establishing communications to be executed by the CPU  11 . 
     This communications establishing process is to provide a communication link between the analog electronic timepiece  10  and the smartphone  40  for execution of the receiving process every second in the above displaying process. 
     This communications establishing process starts in response to, for example, the reception of a request for establishing communications transmitted from the smartphone  40  upon an operational input thereto, or starts upon a detection of a preset time to execute this process. 
     Alternatively, a predetermined user operation on the crown C may start the process. 
     In the communications establishing process, the CPU  11  first determines whether a communication link has already been established (step S 301 ). 
     If the CPU  11  determines that a communication link has already been established, the process of the CPU  11  goes on to step S 304 . 
     If determining that a communication link has not been established, the CPU  11  executes a process for linking with the smartphone  40  (step S 302 ). 
     This linking process may be executed by a well-known method in accordance with a Bluetooth communication protocol. 
     If a link is not established at this time, the CPU  11  repeats the linking process for a preset time period. If a link remains unestablished during the period, the CPU  11  finishes the linking process. 
     The CPU  11  determines whether the establishment of the communication link with the smartphone  40  has succeeded (step S 303 ). 
     If determining that the establishment of the communication link has failed, the CPU  11  finishes the communications establishing process. 
     If the CPU  11  determines that the establishment of the communication link has succeeded, the process of the CPU  11  goes on to step S 304 . 
     In step S 304 , the CPU  11  sends a control signal to the step motor driving circuit  24 , which then operates the step motor  23  to rotate the information display plate  19  such that “LINK” on the information display plate  19  appears through the aperture  8 . 
     The CPU  11  then measures the duration of “LINK” being displayed. 
     The CPU  11  determines whether the duration of “LINK” reaches a predetermined time (step S 305 ). 
     The CPU  11  repeats step S 305  until it is determined that the predetermined time has passed. 
     After the predetermined time passes, the CPU  11  sends a control signal to the step motor driving circuit  24 , which then operates the step motor  23  to return to the normal display mode (step S 306 ). 
     That is, the CPU  11  allows the small transparent window  191  of the information display plate  19  to lie just under the aperture  8 , thereby displaying the current-date sign on the date indicator  18 . 
     The CPU  11  then finishes the communications establishing process. 
     As described above, the analog electronic timepiece  10  according to the embodiment of the present invention includes the dial plate  7  having the aperture  8 ; the rotatable date indicator  18  provided under the dial plate  7  and having the date signs, which are selectively displayed through the aperture  8 ; the information display plate  19  provided between the dial plate  7  and the date indicator  18  and having signs of “TEL”, “MAIL” and “LINK” on its top surface, the signs indicating information different from date information; and the step motor driving circuit  24  which outputs a drive pulse to the step motor  23 , which then operates the gear train mechanism  21  to rotate the information display plate  19  such that one of the small transparent window  191  and the signs of “TEL”, “MAIL” and “LINK” lies just under the aperture  8 . 
     Thus, the analog electronic timepiece  10  can readily display any one of “TEL”, “MAIL” and “LINK” by rotating the information display plate  19  when there is information to be output and the sign associated with the information is to be displayed. 
     The analog electronic timepiece  10  can also display a date sign through the small transparent window  191  and the aperture  8  when there is no information to be output. 
     In this manner, the date information item and the other information items are displayed using the date indicator  18  and the information display plate  19 , respectively; hence, a displayed information item can be switched from one information item to another without the positional reset of the one information item. 
     Also, only a single sign is displayed through the aperture  8 , which can prevent the user from being confused by multiple signs. 
     Furthermore, the date information item and the other information items can be displayed and the displayed item can be switched among these information items without positional changes of the hands  16  and  17  to be used for indicating the time. These information items are less frequently checked by the user than the time information; hence, this can overcome the disadvantage of hindering the user from checking the time while one of the information items is being displayed. 
     Moreover, the analog electronic timepiece  10  may adopt a conventional dial plate configuration intended to display only dates using a date indicator; hence, marks and signs associated with multiple information items are not needed on the dial plate, which can increase design flexibility. 
     Additionally, the date information item and the other information items are displayed using the date indicator  18  and the information display plate  19 , respectively; hence, the display of the date sign, which changes at regular intervals, is not influenced by the information displayed at irregular intervals. This can eliminate the excess operations of the date indicator  18 . 
     In particular, the number of operational steps of a rotary disk, such as the date indicator  18  having many steps for a full circle, can be significantly reduced. This leads to a reduction in power consumption and to quick display of information. 
     In addition, since the information display plate  19  is a rotatable disk and has signs on its top surface, the information display plate  19  can be readily operated with a gear train mechanism. 
     Furthermore, a Geneva drive and a partially toothed gear can rotate the date indicator  18  in partially conjunction with the rotation of the information display plate  19 ; hence, a single step motor can properly switch among multiple information items without a heavy burden on the rotation of the date indicator  18 . 
     Thus, an increase in weight and size caused by an additional step motor can be avoided. 
     In addition, since the information display plate  19  rotates without engaging with the date indicator  18  for a predetermined part of rotation of the information display plate  19 , rotating the information display plate  19  does not involve the torque required to additionally rotate the date indicator  18  at the time of displaying an information item. As a result, a displayed information item can be readily switched among information items without increase in the width of and the voltage of a pulse output from the step motor driving circuit  24 . 
     Moreover, the Bluetooth communication function allows signals about the presence of information to be received substantially in real time from an external device such as a connected smartphone  40 , and an information item corresponding to the information can be displayed using the information display plate  19  when the information is present. As a result, the user can readily detect the presence of information even if the smartphone  40  cannot be held in hand or kept in plain view. 
     Additionally, since such a function is included in an analog electronic timepiece, in particular, a user wearable thing such as a wristwatch, information other than time information can be obtained more quickly and more reliably without compromising the function of the timepiece. 
     In particular, the user can obtain incoming call information and incoming e-mail information quickly. Thus, the user can make a response without fail when a quick response is required. 
     [First Modification] 
     A first modification of the analog electronic timepiece  10  according to the present embodiment will now be described. 
       FIGS. 9A and 9B  illustrate a date indicator  18   a  and an information display plate  19  in an analog electronic timepiece  10  of the first modification. 
     The analog electronic timepiece  10  of the first modification does not use a Geneva drive. Instead, a date indicator driving wheel  214   a , which rotates along with a drive wheel connection gear  211  and the information display plate  19 , rotates in partial mesh with an internal gear of the date indicator  18   a  directly. 
     The other components are identical to those of the analog electronic timepiece  10  in the above-described embodiment; hence, the same reference numerals are assigned and a redundant description thereof is omitted. 
     The date indicator driving wheel  214   a  is a partially toothed gear having teeth only on a range of 90 degrees at a predetermined portion. The other range of 270 degrees does not come into contact with the internal gear of the date indicator  18   a . That is, the portion of the 270-degree range does not rotate the date indicator  18   a.    
     Accordingly, the internal gear of the date indicator  18   a  may have partial teeth provided only on a range that engages with the date indicator driving wheel  214   a.    
       FIG. 10  illustrates a method of displaying information using the date indicator  18   a  and the information display plate  19  in the analog electronic timepiece  10  according to the first modification. 
     Like the date indicator  18  and the information display plate  19  of the above-described embodiment, when a drive wheel connection gear  211  is rotated in the reverse direction from a state where a small transparent window  191  of the information display plate  19  lies just under an aperture  8  ( FIG. 10(   a )), the information display plate  19  is rotated and the date indicator driving wheel  214   a  engages with the internal gear of the date indicator  18   a , which rotates (shifts) date signs ( FIG. 10(   b )). 
     Then, 90-degree rotation of the drive wheel connection gear  211  allows the date indicator driving wheel  214   a  and the date indicator  18   a  to disengage. 
     At this time, the next date sign on the date indicator  18   a  lies just under the aperture  8  and the sign of “TEL” on the information display plate  19  appears through the aperture  8 , as illustrated in  FIG. 10(   c ). 
     The drive wheel connection gear  211  alone further rotates from this state by a maximum angle of 270 degrees in the reverse direction. The first 90-degree rotation of the drive wheel connection gear  211  allows the sign of “MAIL” to appear through the aperture  8 , as illustrated in  FIG. 10(   d ), and the next 90-degree rotation (180 degrees in total) allows the sign of “LINK” to appear through the aperture  8 , as illustrated in  FIG. 10(   e ). 
     Then, further 90-degree rotation (270 degrees in total) of the drive wheel connection gear  211  allows the small transparent window  191  to overlap with the aperture  8 , and one of the date signs on the date indicator  18   a  appears through the small transparent window  191  and the aperture  8 . 
     At the time of date change, a CPU  11  rotates the drive wheel connection gear  211  and the information display plate  19  by 360 degrees in the reverse direction to display the next date through the small transparent window  191  and the aperture  8 . 
     The CPU  11  then rotates the drive wheel connection gear  211  and the information display plate  19  as needed within a range of 270 degrees in the forward direction, and thereby any one of the date and the signs of “TEL”, “MAIL” and “LINK” associated with other information items can be exposed as appropriate without shifting the date indicator  18   a.    
     In summary, according to the first modification of the analog electronic timepiece  10  of the above embodiment, switching between the state where the date indicator  18   a  and the information display plate  19  rotate in meshing engagement with each other and the state where the date indicator  18   a  and the information display plate  19  are disengaged from each other can be achieved with a simpler structure without a Geneva drive. As a result, an increase in the weight and size of the analog electronic timepiece  10  can be avoided. 
     [Second Modification] 
     An analog electronic timepiece  10  of a second modification will now be described. 
       FIG. 11  is a schematic side view of the configuration of a date indicator  18  and an information display plate  19   b  in the analog electronic timepiece  10  of the second modification, shown in the same position and orientation as those in  FIG. 4B . 
     The analog electronic timepiece  10  according to the second modification is identical to the analog electronic timepiece  10  of the above-described embodiment except for the additional information display plate  19   b  and an additional LED  29   b  (illuminator) provided at one side of the information display plate  19   b ; hence, the same reference numerals are assigned to the common components and a redundant description thereof is omitted. 
     The information display plate  19   b  is a light-guide plate. 
     Light incident on a side of the information display plate  19   b  is almost evenly reflected by the undersurface and is output from the top surface. 
     When any one of the signs of “TEL”, “MAIL” and “LINK” on the information display plate  19   b  appears through an aperture  8 , a CPU  11  turns on the LED  29   b  so that light enters the information display plate  19   b  through its side. 
     As a result, when any one of the signs on the information display plate  19   b  appears, the light is emitted from the aperture  8  at the same time. 
     The light-emitting duration time of the LED  29   b  can be set as appropriate. 
     Alternatively, the LED  29   b  may blink or may be driven by pulses at predetermined intervals. 
     In summary, according to the second modification of the analog electronic timepiece  10  in the above present embodiment, the light-guide plate is used as the information display plate  19   b , which can reflect (emit) light for notification of one of the information items; hence, the user can more reliably detect the information output. 
     Note that the above embodiment and its modifications of the present invention may be modified in various ways. 
     For example, although the date indicator  18  and the information display plate  19  rotate in conjunction with each other in the above-described embodiment, this mechanism may be appropriately modified. 
     Each of the date indicator  18  and the information display plate  19  may be rotated individually by a separate motor. 
     Furthermore, although the analog electronic timepiece in the above-described embodiment displays the information items using the two rotary disks, this technique may be appropriately modified. 
     For example, a displayed information item may be switched while reeling a belt which has multiple signs thereon by a motor. 
     Although the analog electronic timepiece in the above-described embodiment displays a date and incoming information received from an external device at the same position, any other information item may also be displayed. 
     For example, the analog electronic timepiece may display a day of the week instead of a date, or a notification based on the schedule managed by the smartphone  40  may be displayed instead of an incoming call or e-mail. 
     Moreover, an information display device having such a configuration should not be limited to a timepiece; hence, hands for indicating information are not essential. 
     Thus, this information display device can readily employ various designs. 
     Although the information to be displayed is received from the smartphone  40  through Bluetooth communications in the above-described embodiment, communications can be established with various other external devices such as mobile phones and mobile computers. 
     Furthermore, an information item to be displayed is not limited to the information obtained from an external device. 
     Displayed information items may be associated with other functions included in the analog electronic timepiece itself, such as alarm setting and mode setting. 
     In addition, the technique may be applied to a decoration function without the necessity of a control operation, such as the function where a design or a pattern preliminarily stored in the analog electronic timepiece is displayed at a predetermined time every day. 
     In the second modification, the light-guide plate allows the information display plate  19   b  itself to emit light using the light from the LED  29   b . Alternatively, the information display plate  19   b  may be directly illuminated with light emitted by the LED  29   b  from above. 
     Furthermore, not single information display plate  19  but multiple information display plates  19  may be provided above the date indicator  18 . 
     The date indicator  18  of the above-described embodiment rotates in conjunction with the rotation of the information display plate  19  while the plate  19  is rotating from the state where the small transparent window  191  lies just under the aperture  8  to the state where “TEL” or “LINK” lies just under the aperture  8 ; however, any other configuration may be used. 
     For example, the date indicator  18  may rotate in conjunction with the rotation of the information display plate  19  while the information display plate  19  is rotating from the state where “TEL” or “LINK” lies just under the aperture  8  to the state where the small transparent window  191  lies just under the aperture  8 . 
     Moreover, the specific configurations, arrangements, values, and orders of the processes in the above embodiment may be modified as appropriate without deviating from the gist of the present invention. 
     Although some embodiments of the present invention have been described, they should not be construed as limitations on the scope of the present invention, which includes the scope of the invention stated in the following claims and equivalents thereto. 
     The entire disclosure of Japanese Patent Application No. 2012-169209 filed on Jul. 31, 2012 including description, claims, drawings, and abstract is incorporated herein by reference in its entirety. 
     Although various exemplary embodiments have been shown and described, the invention is not limited to the embodiments shown. Therefore, the scope of the invention is intended to be limited solely by the scope of the claims that follow.