Electronic clock and control method for electronic clock

Abstract

To provide an electronic watch and a method for controlling an electronic watch that can prevent the movement of hands from becoming unnatural.SOLUTION: An electronic watch comprises: a functional hand that displays split time; a motor that drives the functional hand; driving means that drives the motor; a hand position detection unit that detects the position of the functional hand; and a measuring unit that measures the time elapsed from the start. When cancelling the display of the split time with the functional hand, the driving means starts driving the functional hand with a delay equal to or more than the time obtained by adding, to a predetermined first delay time, the time difference between the time corresponding to a counter value measured by the measuring unit and the time displayed at a hand position detected by the hand position detection unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electronic timepiece and a method for controlling an electronic timepiece. [Background technology]

[0002] Patent Document 1 discloses a technique for a stopwatch capable of displaying split time with hands, in which when canceling the split time display, the technique waits until a timing counter and a hand position counter match, and then drives a step motor that moves the hands.

[0003] As a result, in Patent Document 1, when the split time display is released, the time counter and hand position counter can be made to match without the need for fast-forward driving, which rotates the hands faster than normal, so it is possible to use a step motor that has limitations in terms of how well it can be driven by high-frequency drive pulses, or a step motor that can only be driven at a low frequency required for timing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 4-52428 Summary of the Invention [Problem to be solved by the invention]

[0005] There is known a step motor that detects the rotation of the rotor after outputting a motor drive pulse, and controls the motor to output the next motor drive pulse when it is determined that the rotor has rotated. Such a step motor can be driven at a high drive frequency, but the drive frequency varies because the next pulse is output after the rotor rotation is detected. When using a step motor with such a drive frequency variation, the position of the hands driven by the step motor may overtake the measurement value of a time counter that counts up at a constant frequency. If the measurement is stopped in such a state, it is necessary to reverse the rotation of the hands after stopping them or rotate the hands an extra revolution to match the position of the hands with the time counter, which may result in unnatural movement of the hands. [Means for solving the problem]

[0006] The electronic watch disclosed herein comprises a function hand that displays split time, a motor that drives the function hand, a drive means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measurement unit that measures the elapsed time from the start, and is characterized in that when the drive means cancels the display of the split time by the function hand, it starts driving the function hand with a delay of at least a time obtained by adding to a predetermined first delay time the time difference between the time equivalent to the counter value measured by the measurement unit and the time displayed at the hand position detected by the hand position detection unit.

[0007] The electronic timepiece disclosed herein comprises a function hand that displays split time, a motor that drives the function hand, a drive means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measurement unit that measures the elapsed time from the start, and is characterized in that when the drive means cancels the display of the split time by the function hand, it drives the function hand at high speed to a position that is delayed by a predetermined third delay time from the time equivalent to the counter value measured by the measurement unit.

[0008] The control method for an electronic watch disclosed herein is a control method for an electronic watch that has a function hand that displays split time, a motor that drives the function hand, a driving means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measurement unit that measures the elapsed time from a start, and is characterized in that when the display of the split time by the function hand is to be canceled, the drive of the function hand is started with a delay of at least a time obtained by adding to a predetermined first delay time the time difference between the time equivalent to the counter value measured by the measurement unit and the time displayed at the hand position detected by the hand position detection unit.

[0009] The control method for an electronic watch disclosed herein is a control method for an electronic watch that includes a function hand that displays split time, a motor that drives the function hand, a driving means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measuring unit that measures the elapsed time from a start, and is characterized in that when the display of the split time by the function hand is canceled, the function hand is driven to fast-forward to a position that is delayed by a predetermined third delay time from the time equivalent to the counter value measured by the measuring unit. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front view showing an outline of an electronic timepiece according to a first embodiment. [Diagram 2] FIG. 1 is a circuit diagram showing the circuit configuration of an electronic timepiece according to a first embodiment. [Diagram 3] FIG. 4 is a diagram showing a configuration of a fifth motor in the first embodiment. [Figure 4] FIG. 4 is a circuit diagram showing a configuration of a fifth motor control circuit according to the first embodiment. [Diagram 5] 4 is a flowchart illustrating a control process of the motor control circuit according to the first embodiment. [Figure 6] 4 is a flowchart illustrating a control process of the motor control circuit according to the first embodiment. [Figure 7] 4 is a timing chart showing the operation of the motor control process according to the first embodiment. [Figure 8]4 is a timing chart showing the operation of the motor control process according to the first embodiment. [Figure 9] 4 is a timing chart showing the operation of the motor control process according to the first embodiment. [Figure 10] FIG. 11 is a circuit diagram showing the circuit configuration of an electronic timepiece according to a second embodiment. [Figure 11] 10 is a flowchart illustrating a control process of a motor control circuit according to a second embodiment. [Figure 12] 10 is a flowchart illustrating a control process of a motor control circuit according to a second embodiment. [Figure 13] 10 is a timing chart showing the operation of a motor control process according to a second embodiment. [Figure 14] FIG. 11 is a circuit diagram showing the circuit configuration of an electronic timepiece according to a third embodiment. [Figure 15] 10 is a flowchart illustrating a control process of a motor control circuit according to a fourth embodiment. [Figure 16] 10 is a flowchart illustrating a control process of a motor control circuit according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [First embodiment] An electronic timepiece 1 according to a first embodiment of the present disclosure will now be described with reference to the drawings. The electronic watch 1 is a wristwatch worn on the user's wrist, and is a chronograph watch that has multiple display functions, including a minute chronograph display, a second chronograph display, a 1 / 10 second chronograph display, and a 1 / 500 second chronograph display, in addition to the usual 12-hour display with hour, minute, and second hands.

[0012] FIG. 1 is a front view showing the outline of an electronic timepiece 1 according to this embodiment. 1, the electronic timepiece 1 is equipped with an hour hand 2, a minute hand 3, and a second hand 4 that display the time in 12-hour format, a minute CG hand 5 that performs a minute chronograph display, a second CG hand 6 that performs a second chronograph display, a 1 / 10 second CG hand 7 that performs a 1 / 10 second chronograph display, and a 1 / 500 second CG hand 8 that performs a 1 / 500 second chronograph display. Furthermore, the electronic timepiece 1 is equipped with a crown 9, a button A 11, and a button B 12 as operating members.

[0013] The hour hand 2 and minute hand 3 are arranged coaxially and rotatably in the center of the dial 13 of the electronic timepiece 1 in a plan view perpendicular to the surface of the dial 13. Second hand 4 is rotatably provided on an axis independent of the other hands, on the 9 o'clock side of the center of dial 13 in a plan view. The minute CG hand 5 is provided rotatably on an axis independent of the other hands, on the 6 o'clock side of the center of the dial 13 in a plan view. The second CG hand 6 is provided rotatably on an axis independent of the other hands, on the 12 o'clock side of the center of the dial 13 in a plan view. The 1 / 10 second CG hand 7 is rotatably provided on an axis independent of the other hands, on the 3 o'clock side of the center of the dial 13 in a plan view. The 1 / 500 second CG hand 8 is rotatably provided coaxially with the hour hand 2 and minute hand 3 in the center of the dial 13 in a plan view. A scale indicated by the 1 / 500 second CG hand 8 is provided along the outer periphery of the dial 13. Subdials indicated by the second hand 4, minute CG hand 5, second CG hand 6, and 1 / 10 second CG hand 7 are provided on the dial 13 at the 9 o'clock, 6 o'clock, 12 o'clock, and 3 o'clock positions relative to the center of the dial 13, respectively.

[0014] The hour hand 2, minute hand 3, and second hand 4 move in unison to display the current time. The 1 / 500 second CG hand 8 rotates once in 1 / 10 seconds, and the drive steps during one rotation are divided into 50, so it displays the measurement value of the stopwatch in 1 / 500 second units. Note that the 1 / 500 second CG hand 8 is an example of a functional hand of the present disclosure. Furthermore, the scale along the outer periphery of the dial 13 is a scale divided into 50 parts for the 1 / 500 second CG hand 8, and no scales are provided for the hour hand 2 and minute hand 3. Therefore, a separate scale divided into 60 parts may be provided on the outer periphery of the dial 13. However, since a user can usually tell the time from the positions of the hour hand 2 and minute hand 3, it is not necessarily necessary to provide scales for the hour hand 2 and minute hand 3.

[0015] The 1 / 10 second CG hand 7 rotates once in one second, and the drive steps during one rotation are divided into 10, so it displays the stopwatch measurement value in 1 / 10 second increments. The second CG hand 6 rotates once in 60 seconds, and the drive steps during one rotation are divided into 60, so it displays the stopwatch measurement value in 1 second increments. The minute CG hand 5 rotates once in 60 minutes, and the drive steps during one rotation are divided into 60, so it displays the stopwatch measurement value in 1 minute increments.

[0016] [Circuit configuration of electronic clock] FIG. 2 is a circuit diagram showing the circuit configuration of the electronic timepiece 1. As shown in FIG. 2, the electronic watch 1 includes an IC 20, a first motor 41, a second motor 42, a third motor 43, a fourth motor 44, a fifth motor 45, a switch SW1 which is turned on and off in conjunction with the operation of the A button 11, and a switch SW2 which is turned on and off in conjunction with the operation of the B button 12.

[0017] [Motor configuration] FIG. 3 is a diagram showing the configuration of the fifth motor 45. As shown in FIG. 3, the fifth motor 45 includes a stator 131, a coil 130, and a rotor 133. Both ends of the coil 130 are electrically connected to output terminals O9 and O10 of a driver 51, which will be described later, and the rotor 133 is a magnet magnetized with two poles in the radial direction. Therefore, the fifth motor 45 is a two-pole single-phase stepping motor used for electronic timepieces, and is driven by a drive signal input to the driver 51, which will be described later. The first motor 41 to the fourth motor 44 are two-pole single-phase stepping motors similar to the fifth motor 45, and therefore a description thereof will be omitted.

[0018] The hour hand 2, minute hand 3, and second hand 4 are linked together by a gear train (not shown) and driven by a first motor 41. In this embodiment, the hour hand 2, minute hand 3, and second hand 4 are driven by a single first motor 41, but, for example, a motor that drives the second hand 4 and a motor that drives the minute hand 3 and hour hand 2 may be provided separately. The 1 / 10 second CG hand 7 is driven by a second motor 42 , the second CG hand 6 is driven by a third motor 43 , the minute CG hand 5 is driven by a fourth motor 44 , and the 1 / 500 second CG hand 8 is driven by a fifth motor 45 .

[0019] Switch SW1 is a push switch that is linked to button A 11 located at approximately the 2 o'clock position of the electronic watch 1, and is turned on when button A 11 is pressed and turned off when button A 11 is not pressed. Switch SW2 is a push switch that is linked to button B 12 located at approximately the 4 o'clock position on the electronic watch 1, and is turned on when button B 12 is pressed and turned off when button B 12 is not pressed.

[0020] [IC circuit configuration] 2, the IC20 includes an oscillator circuit 21, a first frequency divider circuit 22, a second frequency divider circuit 23, a stopwatch control circuit 24, a first stopwatch counter 251, a second stopwatch counter 252, a hand position counter 253, a subtractor 254, an adder 255, a split latch 256, a comparator 257, and a timer 26. The IC20 further includes a first motor control circuit 31 for driving the first motor 41, a second motor control circuit 32 for driving the second motor 42, a third motor control circuit 33 for driving the third motor 43, a fourth motor control circuit 34 for driving the fourth motor 44, and a fifth motor control circuit 35 for driving the fifth motor 45.

[0021] The oscillator circuit 21 causes a crystal oscillator (not shown) to oscillate at a high frequency, and outputs an oscillation signal of a predetermined frequency (32768 Hz) generated by this high frequency oscillation to the first frequency divider circuit 22 and the second frequency divider circuit 23. The first frequency divider circuit 22 divides the frequency of the output of the oscillator circuit 21 and supplies a timing signal (1 Hz) to the first motor control circuit 31. The second frequency divider circuit 23 divides the output of the oscillator circuit 21 and supplies a first reference clock (500 Hz) to the first stopwatch counter 251 . The stopwatch control circuit 24 is a circuit that executes the stopwatch function, that is, the chronograph function, and is activated by operating button A 11 and button B 12 when the crown 9 is at the 0th position. Button A 11 is used as a button that instructs the stopwatch control circuit 24 to start and stop time measurement. Button B 12 is used as a button that instructs the stopwatch control circuit 24 to split and reset time measurement. The stopwatch control circuit 24 and the fifth motor control circuit 35 constitute the drive means of the present disclosure.

[0022] The first stopwatch counter 251 counts stopwatch measurement values, i.e., counter values, in units of 1 / 500 seconds based on the first reference clock (500 Hz) input from the second frequency divider circuit 23, and supplies a second reference clock (10 Hz) to the second stopwatch counter 252. The first stopwatch counter 251 is an example of a measurement unit of the present disclosure. The second stopwatch counter 252 counts stopwatch measurement values ​​up to 60 minutes based on the second reference clock (10 Hz). The hand position counter 253 counts up each time the drive of the 1 / 500 second CG hand 8 completes one step, and counts the hand positions from 0 to 49 on a scale divided into 50. The hand position counter 253 is an example of a hand position detection unit of the present disclosure.

[0023] The subtractor 254 outputs to the adder 255 a time difference t 2 corresponding to the difference between the time corresponding to the counter value of the first stopwatch counter 251 and the time displayed by the hand position of the hand position counter 253 . The adder 255 adds the predetermined first delay time t1 and the time difference t2 input from the subtractor 254, and outputs the result to the timer 26 as a preset value.

[0024] The split latch 256 latches the counter value of the first stopwatch counter 251 . The comparator 257 compares the hand position of the hand position counter 253 with the counter value of the first stopwatch counter 251 latched by the split latch 256 . The timer 26 counts down the time input from the adder 255, that is, the time obtained by adding the time difference t2 between the counter value and the hand position to a predetermined first delay time t1.

[0025] [Motor control circuit configuration] The first motor control circuit 31 drives the first motor 41 every second, and is therefore a motor control circuit capable of reducing power consumption, which is used in wristwatches and the like. That is, after outputting a main drive pulse with a small pulse width, the first motor control circuit 31 measures the induced voltage of the coil of the first motor 41 to detect whether the rotor has rotated or not, and if the rotor has not rotated, outputs a correction drive pulse with a fixed pulse width larger than that of the main drive pulse, thereby controlling the rotor to rotate reliably.

[0026] The second motor control circuit 32, the third motor control circuit 33, and the fourth motor control circuit 34, like a typical analog chronograph watch, control the drive of the hands one step at a time by outputting fixed pulses in response to the stopwatch control signal output from the stopwatch control circuit 24. That is, the stopwatch control circuit 24 outputs control signals to the motor control circuits 32, 33, and 34 to drive the motors 42, 43, and 44. Therefore, the second motor control circuit 32 drives the second motor 42 every 1 / 10 seconds, the third motor control circuit 33 drives the third motor 43 every second, and the fourth motor control circuit 34 drives the fourth motor 44 every minute.

[0027] FIG. 4 is a circuit diagram showing the configuration of the fifth motor control circuit 35. As shown in FIG. 4, the fifth motor control circuit 35 includes a driver and detection circuit 50 constituting a motor control unit that detects the rotation of the rotor 133 of the fifth motor 45 and controls switching the polarity of the current flowing through the coil 130. The driver and detection circuit 50 includes a driver 51 that supplies current to the coil 130 of the fifth motor 45, and a current detection circuit 61 that determines whether the current value flowing through the coil 130 is below a predetermined value. In this embodiment, the fifth motor control circuit 35 controls the supply of current to the coil 130 of the fifth motor 45 by turning on the supply of current to the coil 130 of the fifth motor 45 when the current flowing through the coil 130 falls below a predetermined value that is the lower limit, and turning off the supply of current when the on-time during which the supply of power continues has elapsed for a predetermined time, so that a substantially constant current flows through the coil 130. The position of the rotor 133 is estimated based on the off-time during which the supply of power continues to be stopped, and the rotor 133 is determined to have rotated 180 degrees, i.e., one step, and the polarity of the current supplied to the coil 130 is switched to perform driving of the next step. That is, the fifth motor control circuit 35 detects a current value or the like linked to the rotation of the rotor 133 to check the rotation of the rotor 133, and drives the fifth motor 45 by feedback control that performs drive control according to the rotation state of the rotor 133. Note that this embodiment is an example, and as a motor control circuit that controls the motor with a constant current and determines the rotation of the rotor based on the off time and the on time during which the power supply is continued, for example, the control circuit disclosed in JP 2019-176705 A can be used.

[0028] The driver 51 includes two Pch transistors 52, 53, four Nch transistors 54, 55, 56, 57, and two detection resistors 58, 59. The transistors 52 to 57 are controlled by gate signals P1, P2, N1, N2, N3, N4 output from a decoder (not shown), and supply currents in both forward and reverse directions to the coil 130 of the fifth motor 45.

[0029] The current detection circuit 61 includes a first reference voltage generation circuit 62, comparators 641 and 642, and a composite gate 68. The composite gate 68 is a single element having a function equivalent to a combination of AND circuits 661 and 662 and an OR circuit 680. The comparators 641 and 642 compare the voltages generated across the detection resistors 58 and 59 having resistance values ​​R1 and R2 with the voltage of the first reference voltage generating circuit 62, respectively. The drive polarity signal PL is inverted and input to the AND circuit 661, and the drive polarity signal PL is input to the AND circuit 662 as is, so that one output of the comparators 641, 642 selected by the drive polarity signal PL is output as the detection signal DT1.

[0030] The first reference voltage generating circuit 62 is set so as to output a potential equivalent to the voltage generated across the detection resistors 58, 59 when the current flowing through the coil 130 is at a lower limit current value Imin. Therefore, when the current I flowing through the coil 130 is equal to or greater than the lower limit current value Imin, the voltage generated across the detection resistors 58, 59 exceeds the output voltage of the first reference voltage generating circuit 62, causing the detection signal DT1 to go to H level. On the other hand, when the current I is below the lower limit current value Imin, the detection signal DT1 goes to L level.

[0031] [Control processing of motor control circuit] When the stopwatch control circuit 24 of the IC 20 detects that the A button 11 has been operated to start the chronograph function, it starts the chronograph, that is, the stopwatch measurement. The operation of the 1 / 500 second CG hand 8 when the chronograph function is executed, that is, the control by the fifth motor control circuit 35, will be described with reference to the flowcharts of FIGS. 5 and 6 and the timing charts of FIGS. It should be noted that the operation of the other 1 / 10 second CG hand 7, second CG hand 6 and minute CG hand 5, that is, the control by the second motor control circuit 32, the third motor control circuit 33 and the fourth motor control circuit 34, is omitted here because the method of controlling the drive of the hands one step at a time by the drive signal output from the stopwatch control circuit 24 is the same as in a typical analog chronograph watch.

[0032] As shown in FIG. 5 and FIG. 6, first, in step S101, the stopwatch control circuit 24 determines whether or not there is an input to SW1. If the result of the determination in step S101 is Yes, the stopwatch control circuit 24 determines in step S102 whether or not the watch is in a split state in which the 1 / 500 second CG hand 8 displays a split time.

[0033] If determined as No in step S102, the stopwatch control circuit 24 determines whether or not it is a start state for performing 1 / 500 second chronograph display by the 1 / 500 second CG hand 8, in step S103. If the result of the determination in step S103 is No, the stopwatch control circuit 24 sets the start state in step S104. Then, the fifth motor control circuit 35 counts down the second delay time t3 in step S105. After that, the fifth motor control circuit 35 starts moving the 1 / 500 second CG hand 8 in response to the control signal from the stopwatch control circuit 24 in step S106, and returns to step S101 to repeat the process.

[0034] On the other hand, if the result of the determination in step S103 is Yes, the stopwatch control circuit 24 sets the first stopwatch counter 251 to a stopped state and stops the counting in step S107. Then, the stopwatch control circuit 24 determines whether the hand position of the 1 / 500 second CG hand 8 matches the counter value of the first stopwatch counter 251 in step S108. Specifically, the comparator 257 compares the hand position of the hand position counter 253 with the counter value of the first stopwatch counter 251. If the result of the determination in step S108 is No, the stopwatch control circuit 24 returns to step S108 and repeats the process. On the other hand, if the result of the determination in step S108 is Yes, the fifth motor control circuit 35 stops the movement of the 1 / 500 second CG hand 8 in response to the control signal from the stopwatch control circuit 24 in step S109, and returns to step S101 and repeats the process.

[0035] Specifically, as shown in the timing chart of Fig. 7, when the A button 11 is operated in the stop state to input SW1, the reset is released and the start state is set. In other words, measurement by the first stopwatch counter 251 is started. Then, the first stopwatch counter 251 starts counting the counter value, and the counter value is held as a split value in the split latch 256. Then, when the second delay time t3 has elapsed since the counter value started to be counted, the fifth motor control circuit 35 starts outputting a drive signal to the fifth motor 45 via the output terminals O9 and O10, and starts moving the 1 / 500 second CG hand 8. That is, in this embodiment, when the first stopwatch counter 251 starts measuring, the movement of the 1 / 500 second CG hand 8 starts in a state delayed by the second delay time t3 from the counter value, so that the 1 / 500 second CG hand 8 can be prevented from overtaking the counter value. Therefore, when stopping measurement by the first stopwatch counter 251, there is no need to stop the 1 / 500 second CG hand 8 and then reverse it or rotate the 1 / 500 second CG hand 8 an extra full revolution to match the counter value and the hand position, thereby preventing the 1 / 500 second CG hand 8 from behaving unnaturally.

[0036] Also, when the A button 11 is operated in the start state to input SW1, the stop state is set. Then, the counting of the counter value of the first stopwatch counter 251 is stopped, and the updating of the counter value latched in the split latch 256 is also stopped. Then, when the hand position counted by the hand position counter 253 and the counter value of the first stopwatch counter 251 match, the fifth motor control circuit 35 stops outputting the drive signal to the fifth motor 45, and stops the movement of the 1 / 500 second CG hand 8.

[0037] Furthermore, when the A button 11 is operated to input SW1 in this stopped state, the stop is released and the start state is reset, that is, measurement by the first stopwatch counter 251 is restarted. Then, the first stopwatch counter 251 restarts counting the counter value, and the counter value is latched as a split value in the split latch 256. Then, when the second delay time t3 has elapsed since the counter value restarted counting, the fifth motor control circuit 35 restarts outputting the drive signal to the fifth motor 45 via the output terminals O9 and O10, and restarts the movement of the 1 / 500 second CG hand 8. That is, in this embodiment, when the measurement by the first stopwatch counter 251 is restarted, the movement of the 1 / 500 second CG hand 8 is restarted in a state delayed by the second delay time t3 from the counter value, so that the 1 / 500 second CG hand 8 can be prevented from overtaking the counter value. Therefore, when stopping measurement by the first stopwatch counter 251, there is no need to stop the 1 / 500 second CG hand 8 and then reverse it or rotate the 1 / 500 second CG hand 8 an extra full revolution to match the counter value and the hand position, thereby preventing the 1 / 500 second CG hand 8 from behaving unnaturally.

[0038] Here, in this embodiment, as described above, the fifth motor control circuit 35 drives the fifth motor 45 by feedback control, and therefore it is possible to stabilize the driving of the fifth motor 45. Therefore, it is possible to prevent the movement of the 1 / 500 second CG hand 8 from becoming unnatural, and it is possible to speed up the driving of the fifth motor 45. At this time, the fifth motor control circuit 35 feedback controls the fifth motor 45 so that the hand movement period t0 of the 1 / 500 second CG hand 8 by the fifth motor 45 converges to a target value that is an integer multiple of the measurement unit of the first stopwatch counter 251. In this embodiment, the first stopwatch counter 251 performs measurement in units of 1 / 500 seconds based on the first reference clock (500 Hz) as described above. Then, the fifth motor control circuit 35 sets the target value to 1 / 500 seconds, which is an integral multiple of the above measurement unit, and feedback controls the fifth motor 45 so that the hand movement period t0 of the 1 / 500 second CG hand 8 converges to the above target value of 1 / 500 seconds. Specifically, after determining that the rotor 133 has rotated, the fifth motor control circuit 35 switches the polarity of the current supplied to the fifth motor 45 and controls the timing for starting the next step of driving to match the first reference clock (500 Hz), thereby driving the 1 / 500 second CG hand 8 at a value close to 1 / 500 second. This makes it possible to reduce variation in the hand movement cycle t0 of the fifth motor 45.

[0039] Furthermore, in this embodiment, the second delay time t3 is preset to be greater than the sum of the maximum integral value of the difference between the hand movement cycle t0 of the fifth motor 45 and the target value of 1 / 500 seconds, and the maximum time from the input of a stop or split operation, i.e., SW1 or SW2, until the 1 / 500 second CG hand 8 stops. This allows the second delay time t3 to be set taking into account variations in the hand movement cycle t0 and the delay time from the input of SW1 and SW2, so that it is possible to more reliably prevent the 1 / 500 second CG hand 8 from overtaking the counter value.

[0040] Returning to FIG. 5 and FIG. 6, if the result of the determination in step S102 is Yes, the stopwatch control circuit 24 determines in step S110 whether or not the stopwatch is in a start state. If the result of the determination in step S110 is Yes, the stopwatch control circuit 24 sets the split stop state in which the 1 / 500 second CG hand 8 displays the split value in step S111, and returns to step S101 to repeat the process. That is, when SW1 is input in the start state, the stopwatch control circuit 24 sets the split stop state and stops the measurement by the first stopwatch counter 251. On the other hand, if the result of the determination in step S110 is No, the stopwatch control circuit 24 sets the watch to the split state in step S112, and returns to step S101 to repeat the process.

[0041] Returning to step S101, if the result of the determination in step S101 is No, the stopwatch control circuit 24 determines, in step S113, whether or not an input has been made to SW2. If the result of the determination in step S113 is No, the stopwatch control circuit 24 returns to step S101 and repeats the process. On the other hand, if the result of step S113 is Yes, the stopwatch control circuit 24 determines in step S114 whether or not the stopwatch control circuit 24 is in a reset state, that is, whether or not measurement by the first stopwatch counter 251 has been stopped and the counter value is 0.

[0042] If the result of the determination in step S114 is Yes, the stopwatch control circuit 24 returns to step S101 and repeats the process. On the other hand, if the result of determination in step S114 is No, the stopwatch control circuit 24 determines whether or not the watch is in a split state, in step S115.

[0043] If the result of the determination in step S115 is No, the stopwatch control circuit 24 determines in step S116 whether or not the stopwatch control circuit 24 is in a start state. If the result of the determination in step S116 is No, the stopwatch control circuit 24 sets the reset state in step S117. That is, when SW2 is input in the split stop state, the stopwatch control circuit 24 sets the counter value by the first stopwatch counter 251 and the split value latched in the split latch 256 to 0. Then, in step S118, the fifth motor control circuit 35 drives the 1 / 500 second CG hand 8 to the 0 position in response to the control signal from the stopwatch control circuit 24, and returns to step S101 to repeat the process.

[0044] On the other hand, if the result of the determination in step S116 is Yes, the stopwatch control circuit 24 sets the watch to the split state in step S119. Then, the stopwatch control circuit 24 determines whether the hand position of the 1 / 500 second CG hand 8 matches the split value in step S120. Specifically, the comparator 257 compares the hand position of the hand position counter 253 with the split value latched by the split latch 256.

[0045] If the result of the determination in step S120 is No, the stopwatch control circuit 24 returns to step S120 and repeats the process. On the other hand, if the result of the determination in step S120 is Yes, the fifth motor control circuit 35 stops the movement of the 1 / 500 second CG hand 8 in response to the control signal from the stopwatch control circuit 24 in step S121, and then returns to step S101 and repeats the process.

[0046] Returning to step S115, if the result of the determination in step S115 is Yes, the stopwatch control circuit 24 determines in step S122 whether or not the stopwatch control circuit 24 is in the start state. If the result of the determination in step S122 is Yes, the stopwatch control circuit 24 sets the start state in step S123. Then, the stopwatch control circuit 24 checks the countdown of the time obtained by adding the time difference t2 to the predetermined first delay time t1 by the timer 26 in step S124. Then, the fifth motor control circuit 35 starts moving the 1 / 500 second CG hand 8 in response to the control signal from the stopwatch control circuit 24 in step S125.

[0047] Specifically, as shown in the timing chart of Fig. 8, after SW1 is input to set the start state, SW2 is input to set the split state, and when SW2 is input in this state, the split state is released. At this time, the subtracter 254 calculates a time difference t2 corresponding to the difference between the counter value of the first stopwatch counter 251 and the hand position of the hand position counter 253, and outputs it to the adder 255. Then, the adder 255 adds a predetermined first delay time t1 to the time difference t2 input from the subtracter 254, and outputs it to the timer 26. After that, when the timer 26 counts down the time obtained by adding the time difference t2 to the first delay time t1, the fifth motor control circuit 35 starts moving the 1 / 500 second CG hand 8 in response to a control signal from the stopwatch control circuit 24. That is, in this embodiment, when the fifth motor control circuit 35 cancels the display of the split time by the 1 / 500 second CG hand 8, it waits for a time difference t2, which is the time until the counter value of the first stopwatch counter 251 and the hand position of the hand position counter 253 match, and then waits for a predetermined first delay time t1 before starting the movement of the 1 / 500 second CG hand 8. This makes it possible to prevent the hand position of the 1 / 500 second CG hand 8 from overtaking the counter value of the first stopwatch counter 251. Therefore, when stopping the measurement by the first stopwatch counter 251, it is not necessary to reverse the 1 / 500 second CG hand 8 after stopping it or to rotate the 1 / 500 second CG hand 8 an extra revolution to match the counter value and the hand position, so that it is possible to prevent the movement of the 1 / 500 second CG hand 8 from becoming unnatural.

[0048] Here, in this embodiment, the first delay time t1 is set to be larger than the sum of the maximum integral value of the difference between the movement cycle t0 of the fifth motor 45 and the target value of 1 / 500 seconds, as well as the maximum time from input of SW1 or SW2 until the 1 / 500 second CG hand 8 stops, just like the second delay time t3. Specifically, the first delay time t1 is set to the same value as the second delay time t3. As a result, the first delay time t1 is set in consideration of the variation in the movement cycle t0 and the delay time from input of SW1 and SW2, so that it is possible to more reliably prevent the 1 / 500 second CG hand 8 from overtaking the counter value. In this embodiment, the first delay time t1 is set to the same value as the second delay time t3, but is not limited to this, and different times may be set for the first delay time t1 and the second delay time t3.

[0049] 5 and 6, if the result of the determination in step S122 is No, the stopwatch control circuit 24 sets the stop state in step S126. Then, in step S127, the fifth motor control circuit 35 drives the 1 / 500 second CG hand 8 in fast forward fashion to the position of the counter value of the first stopwatch counter 251 in response to the control signal from the stopwatch control circuit 24, and returns to step S101 to repeat the process.

[0050] Specifically, as shown in the timing chart of Fig. 9, after SW1 is input to enter the start state, SW2 is input to set the split state, and when SW1 is input in this state, the split stop state is set. In this state, measurement by the first stopwatch counter 251 is stopped. The split value in the split state is latched in the split latch 256, and the 1 / 500 second CG hand 8 is stopped at the position of the split value. In this state, when SW2 is further input, the split state is released. Then, the counter value of the first stopwatch counter 251 is latched in the split latch 256. Furthermore, a fast-forward drive signal is output from the output terminals O9 and O10 of the fifth motor control circuit 35 to the fifth motor 45, and the 1 / 500 second CG hand 8 is driven in fast forward until the counter value of the first stopwatch counter 251 matches the hand position counted by the hand position counter 253.

[0051] [Effects of the first embodiment] In this embodiment, the following effects can be obtained. In this embodiment, when the fifth motor control circuit 35 cancels the display of the split time by the 1 / 500 second CG hand 8, it delays the start of the drive of the 1 / 500 second CG hand 8 by the time difference t2 between the time corresponding to the counter value measured by the first stopwatch counter 251 and the time displayed at the hand position detected by the hand position counter 253, that is, the time until the counter value and the hand position match. Furthermore, the fifth motor control circuit 35 delays the start of the drive of the 1 / 500 second CG hand 8 by a predetermined first delay time t1 in addition to this. As a result, when the split time display is canceled, the movement of the 1 / 500 second CG hand 8 starts in a state delayed by a predetermined time from the time corresponding to the counter value of the first stopwatch counter 251, so that it is possible to prevent the 1 / 500 second CG hand 8 from overtaking the counter value. Therefore, when stopping measurement by the first stopwatch counter 251, there is no need to stop the 1 / 500 second CG hand 8 and then reverse it or rotate the 1 / 500 second CG hand 8 an extra full revolution to match the counter value and the hand position, thereby preventing the 1 / 500 second CG hand 8 from behaving unnaturally.

[0052] In this embodiment, when starting measurement by the first stopwatch counter 251 and when restarting measurement, the movement of the 1 / 500 second CG hand 8 starts with a delay of the predetermined second delay time t3 from the time corresponding to the counter value of the first stopwatch counter 251, so that it is possible to prevent the 1 / 500 second CG hand 8 from overtaking the counter value. Therefore, when stopping measurement by the first stopwatch counter 251, it is not necessary to reverse the 1 / 500 second CG hand 8 after stopping it or to rotate the 1 / 500 second CG hand 8 an extra revolution to match the counter value and the hand position, so that it is possible to prevent the movement of the 1 / 500 second CG hand 8 from becoming unnatural.

[0053] In this embodiment, the fifth motor control circuit 35 drives the fifth motor 45 by feedback control, and therefore it is possible to stabilize the driving of the fifth motor 45. As a result, it is possible to prevent the movement of the 1 / 500 second CG hand 8 from becoming unnatural, and it is possible to speed up the driving of the fifth motor 45.

[0054] In this embodiment, the fifth motor control circuit 35 feedback controls the fifth motor 45 so that the movement period t0 of the 1 / 500 second CG hand 8 by the fifth motor 45 converges to a target value of 1 / 500 second, which is the same as the measurement unit of the first stopwatch counter 251. This makes it possible to reduce variation in the movement period t0 of the fifth motor 45.

[0055] In this embodiment, the first delay time t1 and the second delay time t3 are set to be greater than the sum of the maximum integral value of the difference between the hand movement cycle t0 of the fifth motor 45 and the target value of 1 / 500 seconds, and the maximum time from the input of a stop or split operation, i.e., SW1 or SW2, until the 1 / 500 second CG hand 8 stops. This allows the second delay time t3 to be set taking into account the variation in the hand movement cycle t0 and the delay time from the input of SW1 and SW2, so that it is possible to more reliably prevent the 1 / 500 second CG hand 8 from overtaking the counter value.

[0056] [Second embodiment] Next, an electronic timepiece 1A according to a second embodiment of the present disclosure will be described with reference to Figures 10 to 12. Note that in the second embodiment, components that are the same as or similar to those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted or simplified. FIG. 10 is a circuit diagram showing the circuit configuration of an electronic timepiece 1A according to the second embodiment. As shown in FIG. 10, the electronic timepiece 1A includes an IC 20A, a first motor 41, a second motor 42, a third motor 43, a fourth motor 44, a fifth motor 45, a switch SW1, and a switch SW2.

[0057] [IC circuit configuration] The IC20A includes an oscillator circuit 21A, a first frequency divider circuit 22A, a second frequency divider circuit 23A, a stopwatch counter 250A, a split latch 256A, a timer 26A, a CPU (Central Processing Unit) 271A, a ROM (Read Only Memory) 272A, a RAM (Random Access Memory) 273A, an input circuit 274A, and a bus 275A. The IC20A further includes a first motor control circuit 31A, a second motor control circuit 32A, a third motor control circuit 33A, a fourth motor control circuit 34A, and a fifth motor control circuit 35A.

[0058] Similar to the oscillator circuit 21 of the first embodiment, the oscillator circuit 21A causes a crystal oscillator (not shown) to oscillate at a high frequency, and outputs an oscillation signal of a predetermined frequency (32768 Hz) generated by this high-frequency oscillation to the first frequency divider circuit 22A and the second frequency divider circuit 23A. The first frequency divider circuit 22A divides the frequency of the output of the oscillator circuit 21A and supplies a timing signal (1 Hz) to the first motor control circuit 31A. The second frequency divider circuit 23A divides the output of the oscillator circuit 21A and supplies a first reference clock (500 Hz) to the stopwatch counter 250A and the CPU 271A.

[0059] The stopwatch counter 250A counts stopwatch measurement values, that is, counter values, down to 1 / 10 seconds based on the first reference clock (500 Hz) input from the second frequency dividing circuit 23A.

[0060] The split latch 256A latches the counter value of the stopwatch counter 250A. The timer 26A counts down a time input from the CPU 271A, specifically, a predetermined first delay time t1 plus a time difference t2 between the time corresponding to the counter value and the time displayed by the hand position.

[0061] The ROM 272A and RAM 273A store various programs and data executed by the CPU 271A. The CPU271A realizes each of the above functions according to various programs and data stored in the ROM272A and the RAM273A. Specifically, the CPU271A outputs control signals to the first motor control circuit 31A, the second motor control circuit 32A, the third motor control circuit 33A, the fourth motor control circuit 34A, and the fifth motor control circuit 35A to execute the basic clock function and the stopwatch function. The CPU271A also counts up each time the drive of the 1 / 500 second CG hand 8 ends one step, and counts the hand positions from 0 to 49 on the 50-divided scale. Furthermore, the CPU271A adds a predetermined first delay time t1 to the time difference t2 corresponding to the difference between the counter value of the stopwatch counter 250A and the counted hand position, and outputs the result to the timer 26A as a preset value. That is, in this embodiment, the CPU271A constitutes the driving means of the present disclosure.

[0062] The input circuit 274A outputs the states of SW1 and SW2 to the bus 275A. The bus 275A is used for data transfer between the CPU 271A, the input circuit 274A, the first motor control circuit 31A, the second motor control circuit 32A, the third motor control circuit 33A, the fourth motor control circuit 34A, and the fifth motor control circuit 35A. The first motor control circuit 31A to the fifth motor control circuit 35A control the driving of the first motor 41 to the fifth motor 45 according to control signals input from the CPU 271A via the bus 275A. [Control processing of motor control circuit] Next, the control by the fifth motor control circuit 35A of the second embodiment will be described with reference to the flowcharts of Figures 11 and 12 and the timing chart of Figure 13. In the flowcharts of Figures 11 and 12, the processes of steps S101 to S107, S110 to S117, S119, and S122 to S126 are the same as the processes of steps S101 to S107, S110 to S117, S119, and S122 to S126 in the flowcharts of Figures 5 and 6 of the first embodiment, so their description will be omitted or simplified, and only the processes that differ from the first embodiment will be described below.

[0063] After setting the stop state in step S107, the CPU 271A determines whether or not the difference between the counter value of the stopwatch counter 250A and the hand position of the 1 / 500 second CG hand 8 is n or less in step S201. That is, the CPU 271A determines whether or not the number of remaining steps until the hand position of the 1 / 500 second CG hand 8 moves to the counter value of the stopwatch counter 250A is n or less. Here, in this embodiment, n=2 is set.

[0064] If the result of the determination in step S201 is No, the CPU 271A returns to step S201 and repeats the process. On the other hand, if the result of step S201 is Yes, the fifth motor control circuit 35A starts decelerating the 1 / 500 second CG hand 8 in response to the control signal from the CPU 271A in step S202. That is, the fifth motor control circuit 35A starts decelerating the 1 / 500 second CG hand 8 two pulses before the final pulse until the hand position of the 1 / 500 second CG hand 8 is moved to the counter value of the stopwatch counter 250A.

[0065] In this embodiment, the fifth motor control circuit 35A is set to apply a short brake to the rotor 133 to increase the amount of deceleration control of the rotor 133, thereby starting deceleration movement of the 1 / 500 second CG hand 8. Specifically, the fifth motor control circuit 35A maintains the driver 51 in a high impedance state during normal movement of the 1 / 500 second CG hand 8. Then, when deceleration movement starts, the fifth motor control circuit 35A shorts the terminals O9 and O10 of the driver 51. This applies a short brake to the rotor 133, increasing the amount of deceleration control compared to the high impedance state, and the rotor 133 decelerates further. In this embodiment, as described above, n=2 is set as the setting that allows decelerated hand movement, but this is not limiting. For example, n may be set to the time required for decelerated hand movement of the 1 / 500 second CG hand 8.

[0066] Then, in step S203, the CPU 271A determines whether or not the hand position of the 1 / 500 second CG hand 8 matches the counter value of the stopwatch counter 250A. If the result of the determination in step S203 is No, the CPU 271A returns to step S203 and repeats the process. On the other hand, if the result of step S203 is Yes, the fifth motor control circuit 35A stops the movement of the 1 / 500 second CG hand 8 in response to the control signal from the CPU 271A in step S204, and returns to step S101 to repeat the process.

[0067] Thus, in this embodiment, when the fifth motor control circuit 35A moves the 1 / 500 second CG hand 8 to the counter value of the stopwatch counter 250A and stops it, it starts decelerating the movement of the 1 / 500 second CG hand 8 two pulses before the final pulse. That is, when the fifth motor control circuit 35A stops the 1 / 500 second CG hand 8, it executes an overrun prevention process that reduces the drive speed of the 1 / 500 second CG hand 8. This makes it possible to prevent the rotor 133 from overrunning. Here, in this embodiment, the first delay time t1 and the second delay time t3 are set to be greater than n=2, which allows decelerated movement of the 1 / 500 second CG hand 8. That is, in this embodiment, the fifth motor control circuit 35A moves the 1 / 500 second CG hand 8 with a delay of two or more pulses relative to the counter value of the stopwatch counter 250A, so that when the 1 / 500 second CG hand 8 is stopped, the time required for decelerated movement of the 1 / 500 second CG hand 8 can be secured. Therefore, overrunning of the rotor 133 can be more reliably prevented.

[0068] Furthermore, after the fifth motor control circuit 35A is set to the reset state in step S117, in step S205, the fifth motor control circuit 35A starts fast-forward driving to drive the 1 / 500 second CG hand 8 to the 0 position in response to a control signal from the CPU 271A. Next, in step S206, the CPU 271A determines whether or not the number of remaining steps until the 1 / 500 second CG hand 8 is moved to the 0 position is equal to or less than n.

[0069] If the result of the determination in step S205 is No, the CPU 271A returns to step S205 and repeats the process. On the other hand, if the result of step S205 is Yes, then in step S207, the fifth motor control circuit 35A starts decelerating the hand movement in the same manner as in step S202.

[0070] Then, in step S208, the CPU 271A determines whether or not the hand position of the 1 / 500 second CG hand 8 coincides with the 0 position. If the determination in step S208 is No, the CPU 271A returns to step S208 and repeats the process. On the other hand, if the result of step S208 is Yes, the fifth motor control circuit 35A stops the movement of the 1 / 500 second CG hand 8 in response to the control signal from the CPU 271A in step S209, and returns to step S101 to repeat the process.

[0071] Moreover, after setting the stop state in step S119, the CPU 271A determines whether or not the difference between the split value latched in the split latch 256A and the hand position of the 1 / 500 second CG hand 8 is equal to or smaller than n, in step S210.

[0072] If the determination in step S210 is No, the CPU 271A returns to step S210 and repeats the process. On the other hand, if the result of the determination in step S210 is Yes, then in step S211, the fifth motor control circuit 35A starts decelerating the hand movement in the same manner as in step S202.

[0073] Then, in step S212, the CPU 271A determines whether or not the hand position of the 1 / 500 second CG hand 8 matches the split value. If the determination in step S212 is No, the CPU 271A returns to step S212 and repeats the process. On the other hand, if the result of step S212 is Yes, the fifth motor control circuit 35A stops the movement of the 1 / 500 second CG hand 8 in response to the control signal from the CPU 271A in step S213, and returns to step S101 to repeat the process.

[0074] Also, after the fifth motor control circuit 35A is set to the stop state in step S126, in step S214, it starts fast-forward drive to drive the 1 / 500 second CG hand 8 to the counter value of the stopwatch counter 250A in response to a control signal from the CPU 271A. Next, in step S215, the CPU 271A determines whether or not the number of remaining steps until the 1 / 500 second CG hand 8 is moved to the counter value is equal to or less than n.

[0075] If the result of the determination in step S215 is No, the CPU 271A returns to step S215 and repeats the process. On the other hand, if the result of step S215 is Yes, then in step S216, the fifth motor control circuit 35A starts decelerating the hand movement in the same manner as in step S202.

[0076] Then, in step S217, the CPU 271A determines whether or not the hand position of the 1 / 500 second CG hand 8 matches the counter value. If the determination in step S217 is No, the CPU 271A returns to step S217 and repeats the process. On the other hand, if the result of step S217 is Yes, then in step S218, the fifth motor control circuit 35A stops the movement of the 1 / 500 second CG hand 8 in response to the control signal from the CPU 271A, and returns to step S101 to repeat the process.

[0077] [Effects of the second embodiment] In this embodiment, the following effects can be obtained. In this embodiment, when the fifth motor control circuit 35A stops the 1 / 500 second CG hand 8, it executes an overrun prevention process that reduces the drive speed of the 1 / 500 second CG hand 8. This makes it possible to prevent the rotor 133 from overrunning.

[0078] In this embodiment, the fifth motor control circuit 35A moves the 1 / 500 second CG hand 8 with a delay of two or more pulses relative to the counter value of the stopwatch counter 250A, so that when the 1 / 500 second CG hand 8 is stopped, the time required for decelerating the movement of the 1 / 500 second CG hand 8 can be secured. Therefore, overrunning of the rotor 133 can be more reliably prevented.

[0079] [Third embodiment] Next, an electronic timepiece 1B according to a third embodiment of the present disclosure will be described with reference to Fig. 14. In the second embodiment, the same or similar configurations as those in the first and second embodiments are given the same reference numerals, and descriptions thereof will be omitted or simplified. FIG. 14 is a circuit diagram showing the circuit configuration of an electronic timepiece 1B according to the third embodiment. As shown in FIG. 14, the electronic timepiece 1B includes an IC 20B, a drive unit 200B, a first motor 41B, a second motor 42B, a third motor 43B, a fourth motor 44B, a fifth motor 45B, a switch SW1, and a switch SW2.

[0080] [IC circuit configuration] The IC20A includes an oscillator circuit 21B, a first frequency divider circuit 22B, a stopwatch counter 250B, a split latch 256B, a timer 261B, a CPU 271B, a ROM 272B, a RAM 273B, an input circuit 274B, a bus 275B, an interface circuit 281B, and an output circuit 282B. The IC20B further includes a first motor control circuit 31B, a second motor control circuit 32B, a third motor control circuit 33B, and a fourth motor control circuit 34B.

[0081] Similar to the oscillator circuits 21 and 21A of the first and second embodiments, the oscillator circuit 21B causes a crystal oscillator (not shown) to oscillate at a high frequency, and outputs an oscillation signal of a predetermined frequency (32768 Hz) generated by this high-frequency oscillation to a first frequency divider circuit 22B and a second frequency divider circuit 23B described later.

[0082] The first frequency divider circuit 22B divides the output of the oscillator circuit 21B and supplies a timing signal and a reference clock to the CPU 271B and the stopwatch counter 250B. The stopwatch counter 250B counts stopwatch measurement values, that is, counter values, down to 1 / 10 seconds based on the reference clock input from the first frequency dividing circuit 22B. The split latch 256B latches the counter value of the stopwatch counter 250B. The timer 261B counts down the time input from the CPU 271B.

[0083] The ROM 272B and the RAM 273B store various programs and data executed by the CPU 271B. The CPU 271B realizes the above-mentioned functions according to various programs and data stored in the ROM 272B and the RAM 273B. Specifically, the CPU 271A outputs control signals to the first motor control circuit 31B, the second motor control circuit 32B, the third motor control circuit 33B, and the fourth motor control circuit 34B to execute the basic clock function and the stopwatch function.

[0084] The input circuit 274B outputs the states of SW1 and SW2 to a bus 275B. The bus 275B is used for data transfer between the CPU 271B, the input circuit 274B, the first motor control circuit 31B, the second motor control circuit 32B, the third motor control circuit 33B, the fourth motor control circuit 34B, the interface circuit 281B, and the output circuit 282B. The first motor control circuit 31B to the fourth motor control circuit 34B control the driving of the first motor 41 to the fourth motor 44 according to control signals input from the CPU 271B via the bus 275B.

[0085] The interface circuit 281B is configured by a general serial interface circuit, and is configured to be able to communicate with an interface circuit 291B of the drive unit 200B, which will be described later. The output circuit 282B is configured to be able to communicate with a power supply control circuit 292B and a second frequency divider circuit 23B of the drive unit 200B, which will be described later. Specifically, the IC20B outputs a drive signal EN and an oscillation signal (32768 Hz) to the drive unit 200B via the output circuit 282B. The IC20B is an example of the control means of the present disclosure.

[0086] [Drive circuit configuration] The driving unit 200B includes a second frequency divider circuit 23B, a stopwatch control circuit 24B, a hand position counter 253B, a split latch 258B, a comparator 257B, a timer 262B, an interface circuit 291B, a power supply control circuit 292B, and a fifth motor control circuit 35B. The driving unit 200B is an example of the driving means of the present disclosure.

[0087] The second frequency divider circuit 23B divides the frequency of the oscillation signal (32768 Hz) input via the output circuit 282B, and supplies a reference clock to the stopwatch control circuit 24B. The stopwatch control circuit 24B is a circuit that executes the stopwatch function, that is, the chronograph function, similar to the stopwatch control circuit 24 of the first embodiment described above. In this embodiment, the stopwatch control circuit 24B counts the stopwatch measurement value in 1 / 500 second units, that is, the counter value, based on the reference clock input from the second frequency division circuit 23B. Furthermore, the stopwatch control circuit 24B adds a predetermined first delay time t1 to a time difference t2 corresponding to the difference between the counter value and the hand position of the hand position counter 253B, and outputs the result as a preset value to the timer 262B.

[0088] The hand position counter 253B, like the hand position counter 253 in the first embodiment described above, counts up each time the drive of the 1 / 500 second CG hand 8 completes one step, and counts the hand positions from 0 to 49 on a scale divided into 50 divisions. The split latch 258B latches the counter value of the stopwatch control circuit 24B. Comparator 257B compares the needle position of needle position counter 253B with the counter value latched in split latch 258B. The timer 262B counts down a time obtained by adding a time difference t2 between the counter value and the hand position to the first delay time t1 input from the stopwatch control circuit 24B.

[0089] The interface circuit 291B is configured by a general serial interface circuit, and is configured to be able to communicate with the interface circuit 281B of the IC 20B. The power supply control circuit 292B turns on / off the power supply of the drive unit 200B in response to a drive signal EN output from the IC 20B via the output circuit 282B. In this embodiment, when the stop state, split state, or split stop state is set, the IC20B outputs a drive signal EN to the power supply control circuit 292B to turn off the power supply to the drive unit 200B. That is, in this embodiment, in the stop state, split state, or split stop state in which the movement of the 1 / 500 second CG hand 8 is stopped, the IC20B stops the power supply to the drive unit 200B. Therefore, power consumption can be reduced.

[0090] [Effects of the third embodiment] In this embodiment, the following effects can be obtained. In this embodiment, the driving unit 200B and the IC 20B that controls the driving unit 200B are provided separately, so that the degree of freedom in design variations of the driving unit 200B and the IC 20B can be increased.

[0091] In this embodiment, in the stop state where the 1 / 500 second CG hand 8 is stopped, the split state, and the split stop state, the IC 20B stops the power supply to the drive unit 200B. Therefore, power consumption can be reduced.

[0092] [Fourth embodiment] Next, an electronic timepiece according to a fourth embodiment of the present disclosure will be described with reference to Figures 15 and 16. The electronic timepiece according to the fourth embodiment has a similar configuration to the electronic timepiece 1 according to the first embodiment described above.

[0093] Figures 15 and 16 are flowcharts for explaining the control process of the fifth motor control circuit of the fourth embodiment. In the flowcharts of Figures 15 and 16, the processes of steps S101 to S123 and S126 to S127 are the same as the processes of steps S101 to S123 and S126 to S127 in the flowcharts of Figures 5 and 6 of the first embodiment, so their explanation will be omitted or simplified, and only the processes that differ from the first embodiment will be explained below.

[0094] After being set to the start state in step S123, the fifth motor control circuit moves the 1 / 500 second CG hand in fast forward motion to a position obtained by subtracting the third delay time t4 from the counter value of the first stopwatch counter in step S301. Specifically, the fifth motor control circuit drives the 1 / 500 second CG hand in fast forward motion to a position delayed by three steps set as the third delay time t4 from the counter value in step S301. Then, after the 1 / 500 second CG hand has been moved to a position delayed by the third delay time t4 from the counter value in step S301, the fifth motor control circuit moves the 1 / 500 second CG hand normally in response to a control signal from the stopwatch control circuit in step S302. Thus, in this embodiment, when the split time display is released, the movement of the 1 / 500 second CG hand begins delayed by the third delay time t4 from the counter value, thereby preventing the 1 / 500 second CG hand from overtaking the counter value.

[0095] [Effects of the fourth embodiment] In this embodiment, the following effects can be obtained. In this embodiment, when the split time display is cancelled, the movement of the 1 / 500 second CG hand starts delayed by the third delay time t4 from the time corresponding to the counter value, so that the 1 / 500 second CG hand can be prevented from overtaking the counter value. Therefore, when stopping measurement by the first stopwatch counter, it is not necessary to reverse the 1 / 500 second CG hand after stopping it or to rotate the 1 / 500 second CG hand an extra revolution to match the counter value and the hand position, so that the movement of the 1 / 500 second CG hand can be prevented from becoming unnatural.

[0096] [Variations] It should be noted that the present disclosure is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope that can achieve the object of the present disclosure are included in the present disclosure.

[0097] In each of the above-described embodiments, the fifth motor control circuit 35, 35A, 35B delays the second delay time t3 when starting and restarting measurement before starting to move the 1 / 500 second CG hand 8, but this is not limited to this. For example, the present disclosure also includes a case where the second delay time is not provided when starting and restarting measurement.

[0098] In each of the above embodiments, the electronic timepieces 1, 1A, and 1B are wristwatch type, but may be table clocks, for example. The motor control circuit of the present disclosure is not limited to the fifth motor control circuits 35, 35A, and 35B that move the 1 / 500 second CG hand 8, and may be applied to each of the motor control circuits 31 to 34. That is, the present disclosure can be widely used in electronic timepieces to control the hands that move in accordance with the cycle of the reference signal. Furthermore, the present disclosure is not limited to controlling a motor that drives the hands of a timepiece, and can also be applied to a motor control circuit for a hand that moves at a speed corresponding to a reference signal. In this case, the reference signal is not limited to one with a fixed cycle, and may be one in which the reference signal changes according to a measurement value and moves the hands at a speed corresponding to the reference signal. In the above-described embodiments, the motor control circuit that performs feedback control drives one step with a substantially constant current and controls the rotation of the rotor based on the off time when the current supply to the motor is stopped, but the present invention is not limited to this. For example, a motor control circuit may be used that provides a detection coil wound coaxially with a drive coil that drives the rotor, and feeds back the timing of detecting the back induced voltage appearing in the detection coil to supply the next drive pulse, thereby supplying a drive pulse at high speed while checking the rotation of the rotor.

[0099] [Summary of this disclosure] The electronic watch disclosed herein comprises a function hand that displays split time, a motor that drives the function hand, a drive means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measurement unit that measures the elapsed time from the start, and is characterized in that when the drive means cancels the display of the split time by the function hand, it starts driving the function hand with a delay of at least a time obtained by adding to a predetermined first delay time the time difference between the time equivalent to the counter value measured by the measurement unit and the time displayed at the hand position detected by the hand position detection unit. In the present disclosure, when the display of split time by the function hand is cancelled, the driving means delays the start of driving the function hand by the time difference between the time corresponding to the counter value measured by the measurement unit and the time displayed at the hand position detected by the hand position detection unit, that is, the time until the counter value and the hand position match. In addition, the driving means delays the start of driving the function hand by a predetermined first delay time or more. As a result, when the display of split time is cancelled, the movement of the function hand is started in a state delayed by the first delay time from the time corresponding to the counter value of the measurement unit, so that the function hand can be prevented from overtaking the counter value. Therefore, when the measurement by the measurement unit is stopped, it is not necessary to reverse the function hand after stopping it or rotate the function hand an extra revolution to match the counter value and the hand position, so that the movement of the function hand can be prevented from becoming unnatural.

[0100] In the electronic timepiece of the present disclosure, the drive means may initiate drive of the function hand with a predetermined second delay time when starting measurement by the measurement unit and when restarting measurement. As a result, when starting measurement by the measurement unit and when restarting measurement, the movement of the function hand starts with a delay of the predetermined second delay time from the counter value of the measurement unit, so it is possible to prevent the function hand from overtaking the counter value. Therefore, when stopping measurement by the measurement unit, it is not necessary to reverse the function hand after stopping it or to rotate the function hand an extra revolution to match the counter value and the hand position, so it is possible to prevent the function hand from moving unnaturally.

[0101] In the electronic timepiece of the present disclosure, the drive means may drive the motor by feedback control. This makes it possible to stabilize the drive of the motor, thereby preventing the movement of the function hand from becoming unnatural, and also makes it possible to increase the speed of the drive of the motor.

[0102] In the electronic timepiece disclosed herein, the drive means may feedback control the motor so that the period during which the function hand is moved by the motor converges to a target value which is an integer multiple of a measurement unit. This makes it possible to reduce variation in the period of movement of the function hand caused by the motor.

[0103] In the electronic watch disclosed herein, the first delay time may be greater than the sum of the maximum integral value of the difference between the hand movement period and the target value and the maximum time from when the drive means is operated to perform a stop or split operation until when the function hand stops. This allows the first delay time to be set taking into account variations in the hand movement cycle and the delay time from the stop or split operation to the function hand stopping, thereby more reliably preventing the function hand from overtaking the counter value.

[0104] In the electronic timepiece disclosed herein, the drive means may execute an overrun prevention process to reduce the drive speed of the function hand when the drive means stops driving the function hand. This makes it possible to prevent the motor from overrunning.

[0105] In the electronic timepiece of the present disclosure, the first delay time may be longer than the driving time of a step required for the overrun prevention process. As a result, the first delay time by which the movement of the function hand is delayed relative to the counter value measured by the measurement unit is longer than the drive time of the step required for the overrun prevention process, so the overrun prevention process can be executed reliably, and therefore the motor can be prevented from overrunning more reliably.

[0106] The electronic timepiece disclosed herein may further include a control means for controlling the drive means. As a result, the driving means and the control means for controlling the driving means are provided separately, so that the degree of freedom in design variations of the driving means and the control means can be increased.

[0107] In the electronic timepiece disclosed herein, the control means may stop the power supply to the drive means in the split stop state. As a result, in the split stop state, the control means stops the power supply to the drive means, making it possible to reduce power consumption.

[0108] The electronic timepiece disclosed herein comprises a function hand that displays split time, a motor that drives the function hand, a drive means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measurement unit that measures the elapsed time from the start, and is characterized in that when the drive means cancels the display of the split time by the function hand, it drives the function hand at high speed to a position that is delayed by a predetermined third delay time from the time equivalent to the counter value measured by the measurement unit. As a result, when the split time display is cancelled, the movement of the function hand starts delayed by the third delay time from the time corresponding to the counter value of the measurement unit, preventing the function hand from overtaking the counter value. Therefore, when stopping measurement by the measurement unit, it is not necessary to reverse the function hand after stopping it or to rotate the function hand an extra revolution to match the counter value and the hand position, preventing the function hand from moving unnaturally.

[0109] The control method for an electronic watch disclosed herein is a control method for an electronic watch that has a function hand that displays split time, a motor that drives the function hand, a driving means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measurement unit that measures the elapsed time from a start, and is characterized in that when the display of the split time by the function hand is to be canceled, the drive of the function hand is started with a delay of at least a time obtained by adding to a predetermined first delay time the time difference between the time equivalent to the counter value measured by the measurement unit and the time displayed at the hand position detected by the hand position detection unit. As a result, when the split time display is cancelled, the movement of the function hand starts delayed by the first delay time from the time corresponding to the counter value of the measurement unit, preventing the function hand from overtaking the counter value. Therefore, when stopping measurement by the measurement unit, it is not necessary to reverse the function hand after stopping it or to rotate the function hand an extra revolution to match the counter value and the hand position, preventing the function hand from behaving unnaturally.

[0110] The control method for an electronic watch disclosed herein is a control method for an electronic watch that includes a function hand that displays split time, a motor that drives the function hand, a driving means that drives the motor, a hand position detection unit that detects the position of the function hand, and a measuring unit that measures the elapsed time from a start, and is characterized in that when the display of the split time by the function hand is canceled, the function hand is driven to fast-forward to a position that is delayed by a predetermined third delay time from the time equivalent to the counter value measured by the measuring unit. As a result, when the split time display is cancelled, the movement of the function hand starts delayed by the third delay time from the time corresponding to the counter value of the measurement unit, preventing the function hand from overtaking the counter value. Therefore, when stopping measurement by the measurement unit, it is not necessary to reverse the function hand after stopping it or to rotate the function hand an extra revolution to match the counter value and the hand position, preventing the function hand from moving unnaturally. [Explanation of symbols]

[0111] 1, 1A, 1B... electronic clock, 2... hour hand, 3... minute hand, 4... second hand, 5... minute CG hand, 6... second CG hand, 7... 1 / 10 second CG hand, 8... 1 / 500 second CG hand (function hand), 9... crown, 11... A button, 12... B button, 13... dial, 21, 21A, 21B... oscillator circuit, 22, 22A, 22B... first frequency divider circuit, 23, 23A, 23B... second frequency divider circuit, 24, 24B... stopwatch control circuit (drive means), 26, 26A, 261B, 262B... timer, 31, 31A, 31B... first motor control circuit, 32, 32A, 32B... second motor control circuit, 33, 33A, 33B... third motor control circuit, 34, 34A, 34B... fourth motor control circuit, 35, 35A, 35B... fifth motor control circuit (driving means), 41... first motor, 42... second motor, 43... third motor, 44... fourth motor, 45... fifth motor, 50... detection circuit, 51... driver , 52, 53, 54, 55, 56, 57 ... transistors, 58, 59 ... detection resistors, 61 ... current detection circuit, 62 ... first reference voltage generation circuit, 63 ... second reference voltage generation circuit, 68 ... composite gate, 130 ... coil, 131 ... stator, 133 ... rotor, 200B ... drive unit (drive means), 250A, 250B ... stopwatch counter, 251 ... first stopwatch counter (measurement unit), 252 ... second stopwatch counter, 253, 253B... needle position counter (needle position detection unit), 254... subtractor, 255... adder, 256, 256A, 256B, 258B... split latch, 257, 257B... comparator, 271A, 271B... CPU, 272A, 272B... ROM, 273A, 273B... RAM, 274A, 274B... input circuit, 275A, 275B... bus, 281B, 291B... interface circuit, 282B... output circuit.

Claims

1. A function hand that displays split time and A motor that drives the function hand; A driving means for driving the motor; A hand position detection unit that detects the position of the function hand; A measuring unit that measures the elapsed time from the start, When the drive means cancels the display of the split time by the function hand, the drive means starts driving the function hand with a delay of at least a time obtained by adding a time difference between a time corresponding to a counter value measured by the measurement unit and a time displayed at a hand position detected by the hand position detection unit to a predetermined first delay time. An electronic watch characterized by:

2. 2. The electronic timepiece according to claim 1, The driving means starts driving the function hand with a delay of a predetermined second delay time when starting measurement by the measurement unit and when restarting measurement. An electronic watch characterized by:

3. 3. The electronic timepiece according to claim 1, The driving means drives the motor by feedback control. An electronic watch characterized by:

4. 4. The electronic timepiece according to claim 3, The driving means feedback controls the motor so that a period during which the function hand is moved by the motor converges to a target value that is an integer multiple of a measurement unit. An electronic watch characterized by:

5. 5. The electronic timepiece according to claim 4, The first delay time is greater than the sum of the maximum integral value of the difference between the hand movement period and the target value and the maximum time from when the driving means is operated to stop or split until when the function hand stops. An electronic watch characterized by:

6. 6. The electronic timepiece according to claim 1, The driving means performs an overrun prevention process to reduce the driving speed of the function hand when the driving of the function hand is stopped. An electronic watch characterized by:

7. 7. The electronic timepiece according to claim 6, The first delay time is greater than a step drive time required for the overrun prevention process. An electronic watch characterized by:

8. 8. The electronic timepiece according to claim 1, A control means for controlling the driving means is provided. An electronic watch characterized by:

9. 9. The electronic timepiece according to claim 8, The control means stops the power supply to the drive means in a split stop state. An electronic watch characterized by:

10. A function hand that displays split time and A motor that drives the function hand; A driving means for driving the motor; A hand position detection unit that detects the position of the function hand; A measuring unit that measures the elapsed time from the start, The drive means drives the function hand to fast forward to a position that is delayed by a predetermined third delay time from a time corresponding to a counter value measured by the measurement unit when the display of the split time by the function hand is to be cancelled. An electronic watch characterized by:

11. A method for controlling an electronic timepiece comprising: a function hand that displays split time; a motor that drives the function hand; a drive means that drives the motor; a hand position detection unit that detects the position of the function hand; and a measurement unit that measures the elapsed time from a start, comprising the steps of: When the display of the split time by the function hand is to be cancelled, the drive of the function hand is started with a delay of at least a time obtained by adding a time difference between a time corresponding to a counter value measured by the measurement unit and a time displayed at a hand position detected by the hand position detection unit to a predetermined first delay time.

23. A method for controlling an electronic watch comprising the steps of:

12. A method for controlling an electronic timepiece comprising: a function hand that displays split time; a motor that drives the function hand; a drive means that drives the motor; a hand position detection unit that detects the position of the function hand; and a measurement unit that measures the elapsed time from a start, comprising the steps of: When the display of the split time by the function hand is to be released, the function hand is driven in fast forward motion to a position delayed by a predetermined third delay time from a time corresponding to the counter value measured by the measurement unit.

23. A method for controlling an electronic watch comprising the steps of:

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