ELECTRONIC WATCH - CITIZEN HOLDINGS CO LTD

Title:

ELECTRONIC WATCH

Document Type and Number:

WIPO Patent Application WO/2011/043389

Kind Code:

A1

Abstract:

Provided is an electronic watch capable of, even if watch hands having a large moment of inertia are used, accurately determining the rotation and non-rotation thereof. The electronic watch detects rotation by use of a first detection mode determination circuit (12) and a second detection mode determination circuit (13). In the electronic watch, a timing counter (14) for measuring time after the output of a normal drive pulse is followed by a detection pulse selection circuit (151) provided as a changing means for changing the width or frequency of a detection pulse according to the output timing of the detection pulse. The detection pulse detects the rotation of a rotor (10) and simultaneously serves as an electromagnetic brake for the rotor (10). The electromagnetic brake for the rotor (10) is controlled by changing the width or frequency of the detection pulse in a predetermined period, thereby achieving an accurate rotation detection. Alternatively, the setting of the width or frequency of the detection pulse may be changed according to the determination result of the first detection mode, the output voltage of a power supply, and the drivability of the normal drive pulse, instead of according to the output timing of the detection pulse.

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WO/1997/028491	ELECTRONIC TIMEPIECE WITH POWER GENERATING FUNCTION
JP4293477	Structure of self-winding watch

Inventors:

TAKYO YU (JP)
FUKUSHIMA TOSHIAKI (JP)
SHIOTA AKIRA (JP)
MAEDA TOSHINARI (JP)
SUZUKI NOBUAKI (JP)

Application Number:

PCT/JP2010/067566

Publication Date:

April 14, 2011

Filing Date:

October 06, 2010

Export Citation:

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Assignee:

CITIZEN HOLDINGS CO LTD (JP)
CITIZEN WATCH CO LTD (JP)
TAKYO YU (JP)
FUKUSHIMA TOSHIAKI (JP)
SHIOTA AKIRA (JP)
MAEDA TOSHINARI (JP)
SUZUKI NOBUAKI (JP)

International Classes:

G04C3/14; H02P8/02

Domestic Patent References:

WO2008004605A1

2008-01-10

Foreign References:

JP2006271190A	2006-10-05
JP2003259692A	2003-09-12
JPH07120567A	1995-05-12
JPH0833457B2	1996-03-29
JP4165092B2	2008-10-15

Other References: