Timepiece and timepiece control method

Patent metadata

Field	Value
Publication number	US-11334030-B2
Application number	US-202016737391-A
Country	US
Kind code	B2
Filing date	Jan 8, 2020
Priority date	Jan 11, 2019
Publication date	May 17, 2022
Grant date	May 17, 2022

Abstract

A timepiece includes a determination unit configured to execute determination processing of determining whether a braking force that brakes a rotor is preferably large or small, the rotor being rotated in a normal rotation direction to rotate a pointer clockwise; and a detection control unit configured to cause execution of rotation detection processing of detecting rotation of the rotor based on a first induced voltage output to a predetermined terminal among the first terminal and the second terminal being connected to a coil configured to generate a magnetic flux to rotate the rotor in the normal rotation direction, the predetermined terminal being selected based on the determination by the determination unit.

First claim

What is claimed is:

1. A timepiece comprising:
a determination circuit configured to execute a determination process for determining whether a braking force, which is applied to brake a rotor while the rotor is rotating in a normal rotation direction to rotate a watch pointer clockwise, is preferably large or small; and
a detection control circuit configured to:
in response to determination by the determination circuit that the braking force is preferably large, execute a first rotation detection process in which rotation of the rotor is detected based on a first induced voltage output to a second terminal, wherein the second terminal is connected via one end of a coil energized to generate a magnetic flux to rotate the rotor in the normal rotation direction, and
in response to determination by the determination circuit that the braking force is preferably small, execute a second rotation detection process in which rotation of the rotor is detected based on the first induced voltage output to a first terminal and the first induced voltage output to the second terminal, wherein the first terminal is connected via the other end of the coil.

2. The timepiece according to claim 1 , wherein the determination circuit is configured to determine that the braking force is preferably small when a voltage of a battery that supplies electric power necessary for drive current to flow through the coil is lower than a voltage threshold, and determine that the braking force is preferably large when the voltage of the battery is equal to or higher than the voltage threshold.

3. The timepiece according to claim 1 , wherein the determination circuit is configured to determine that the braking force is preferably large when an absolute value of intensity of an external magnetic field applied to the rotor is equal to or larger than a magnetic field threshold.

4. The timepiece according to claim 1 , wherein the determination circuit is configured to determine that the braking force is preferably small when a temperature calculated based on a resistance value of the coil is lower than a temperature threshold.

5. The timepiece according to claim 1 , wherein a second induced voltage is output that flows drive current in a direction opposite to a direction in which the first induced voltage flows drive current, and wherein
the determination circuit is configured to determine that the braking force is preferably large when the first induced voltage or the second induced voltage is output within a predetermined time after an output of a main drive pulse to flow the drive current through the coil ends, and determine that the braking force is preferably small when the first induced voltage or the second induced voltage is output after the predetermined time elapsed.

6. The timepiece according to claim 1 , wherein the determination circuit is configured to determine that the braking force is preferably small when a correction drive pulse is output which is larger in electric power consumption than a main drive pulse for flowing drive current through the coil.

7. The timepiece according to claim 1 , wherein the determination circuit is configured to re-execute the determination process when a correction drive pulse is output which is larger in electric power consumption than a main drive pulse for flowing drive current through the coil, and
the detection control circuit is configured to execute the first rotation detection process when it is determined, as a result of re-execution of the determination process, that the braking force is preferably large, and execute the second rotation detection process when it is determined, as a result of re-execution of the determination process, that the braking force is preferably small.

8. The timepiece according to claim 1 , wherein the determination circuit is configured to:
execute the determination process at a plurality of times;
compare a number of times that it is determined that the braking force is preferably large with a number of times that it is determined that the braking force is preferably small; and
in response to determination that the number of times at which it is determined that the braking forces is preferably large exceeds the number of times at which it is determined that the braking force is preferably small, determine that the braking force is preferably large.

9. The timepiece according to claim 1 , wherein the determination circuit is configured to:
execute the determination process at a plurality of times;
compare a number of times that it is determined that the braking force is preferably large with a number of times that it is determined that the braking force is preferably small; and
in response to determination that the number of times at which it is determined that the braking force is preferably small exceeds the number of times at which it is determined that the braking force is preferably large, determine that the braking force is preferably small.

10. The timepiece according to claim 1 , further comprising a rotation detection circuit configured to identify a reference position at which a load applied to the rotor to rotate the watch pointer clockwise exceeds loads applied to the rotor at other positions by a predetermined threshold or more, wherein a load is determined based on a voltage induced in the coil after a main drive pulse for flowing drive current through the coil is output, wherein
the determination circuit is configured to determine that the braking force is preferably small when the rotation detection circuit is not able to identify the reference position.

11. A timepiece comprising:
a motor that includes a rotor energized to rotate a watch pointer;
a determination circuit configured to determine a magnitude of a braking force applied to brake the rotor, wherein the determination circuit is configured to determine whether the braking force is preferably large or small;
a detection control circuit configured to select, based on a determination result of the determination circuit, a first rotation detection process for detecting rotation of the rotor or a second rotation detection process which is different from the first rotation detection process and whose braking force is different from that of the first rotation detection process,
wherein the detection control circuit configured to:
in response to determination by the determination circuit that the braking force is preferably large, select the first rotation detection process; and
in response to determination by the determination circuit that the braking force is preferably small, select the second rotation detection process; and
a rotation detection circuit configured to detect rotation of the rotor in a rotation detection process selected by the detection control circuit.

Assignees

• Seiko Instr Inc

Inventors

• Yamamoto Kosuke

Classifications

• H02P8/24

  Arrangements for stopping (H02P8/32 takes precedence) · CPC title

• H02P8/34

  Monitoring operation (H02P8/36 takes precedence) · CPC title

• H02P8/02

  specially adapted for single-phase or bi-pole stepper motors, e.g. watch-motors, clock-motors · CPC title

• G04C3/143 Primary

  Means to reduce power consumption by reducing pulse width or amplitude and related problems, e.g. detection of unwanted or missing step · CPC title

• G04C3/14 Primary

  incorporating a stepping motor (G04C3/02 - G04C3/12 take precedence {; generating commutating pulses in primary clocks G04C13/0463}) · CPC title