Conventionally, an analog electronic timepiece such as a wrist watch, etc., has a structure in which have time hands provided on a display unit rotate. The current time is recognized by the rotational positions of an hour hand, a minute hand, and a second hand that are the hands. Since such a wrist timepiece is small-sized, the visibility of the hands and accuracy of the displayed time are demanded. Especially in a wrist watch, downsizing and low power consumption are demanded. To meet this demand, small thin hands must be used. Therefore, the visibility has been poor.
If, for example, a thick second hand is used to improve the visibility, a weight of the second hand becomes heavy, causing a concern that the displayed time is deviated with only a small impact, that is, degradation of anti-shock property of the timepiece. To improve such an anti-shock property, a retentive power of a step motor that is a driving source should be increased. However, this method can not be employed because the power consumption during driving increases.
Mechanisms to cancel the deviation of the displayed time when an impact is applied externally are disclosed in, for example, Patent Documents 1 and 2 below.
The technique disclosed in Patent Document 1 corrects a deviation of the displayed time by executing rotation control such as outputting a compensation driving signal to a step motor, delaying a normal driving signal until an impact is ceased, etc. when the rotor detects a counter electromotive force generated while being jolted due to an impact. The technique disclosed in Patent Document 2 facilitates detection of an impact by periodically amplifying a counter electromotive force generated when the impact is detected and the level of this counter electromotive force.
Patent Document 1: Japanese Patent Application Laid-Open Publication No. S65-110073
Patent Document 2: Japanese Patent Application Publication No. S61-61356