| 摘要 |
PURPOSE:To inform the user of the existence of the magnetic field by a sound emitted from a sound emitting mechanism when the electronic watch detects external magnetic field, if any, by means of a pointer made of a magnetic material and a rotor load detecting part constructed in IC. CONSTITUTION:Among pointers which are driven by a step motor comprising a stator 1, a rotor 2 and a coil 3 through a train of wheel, the second hand 40 is composed of a magnetic material while the minute hand 41 and the hour hand 42 of a non-magnetic material. It is found that the rotor fails to rotate out of control when the magnetic flux generated with the coil 3 is disturbed by the magnetic flux due to the external magnetic field. To overcome the trouble, it is arranged that a sound emitting mechanism provided in the electronic watch emits sound when any external magnetic field is detected by sensing the rotor load. Therefore, the electronic watch can be protected from any strong magnetic field. |
