1. Field of the Invention
The present invention relates to a hand position detecting device and method which detects the rotational positions of seconds, center and hour hands.
2. Description of the Related Art
In the past, a hand position detecting device which detects the rotational positions of hands of a timepiece is known, as disclosed by Japanese Published Unexamined Application 2000-162336. This device comprises a first drive system in which a first drive motor transmits its rotation to a seconds wheel which in turn causes a seconds hand to sweep around a dial, a second drive system in which a second drive motor transmits its rotations to the center and hour wheels to cause the seconds and hour hands, respectively, to sweep around the dial. This device also includes a photosensor which, when the seconds, center and hour wheels of the first and second drive systems are rotated after pointing to the same direction on the same axis, optically detects, with the aid of a light emission element and a photo detection element included in the photosensor, a first, a second and a third light-passing apertures provided in the seconds, center and hour wheels, respectively, such that the respective rotational positions of the seconds, center and hour wheels and hence the seconds, center and hour hands are determined based on detected signals from the photosensor.
However, in this apparatus, the moving positions of the seconds, center and hour hands are only determined. Thus, when it is determined that these hands move around the dial correctly, they are required to continue to do so normally. However, when the positions of the seconds, minute and hour hands cannot be detected, such detection tends to be repeatedly many times, thereby consuming a significant amount of battery power.
It is therefore an object of the present invention to provide a hand position detecting apparatus and method for stopping the detection of the hand positions when the seconds, center and hour hand positions cannot be detected, thereby preventing useless power consumption.