The present invention relates to switch devices which each are turned on against a user's intention and electronic devices which each include such switch device.
Wristwatches are known which each illuminate its face or liquid crystal time display unit with a luminescence element such as a lamp or electronic luminescence element so as to allow for us to recognize the time even in a dark place.
Wristwatches of this kind include some which is provided with a lamp which is lighted up in response to the user turning on a specific switch, and some which are lighted up for a predetermined interval of time in response to the user's turning on a switch.
As shown in U.S. Pat. No. 5,612,931, wristwatches are known which include a posture detection switch which detects one motion of a user's gestures made when the user looks at the wristwatch to thereby light on a lamp.
Whenever the user desires to illuminate the face of the wristwatch, however, the user must manipulate the switch. Thus, for example, when the user' hands are occupied with some baggage, the manipulation of the wristwatch is troublesome.
For instance, in a wristwatch which uses a posture detection switch which detects that the face of the wristwatch is inclined up at 12 o'clock for the user to look at the face to thereby light up the lamp, it is unnecessary to manipulate the switch to light up the lamp. However, even in that case, when the wristwatch takes such posture, the lamp would directly be lighted up, thereby inviting useless electric power consumption, and shortening the battery longevity.
Therefore, it is an object of the present invention to provide a switch device whose operation is never performed without the user's intended motion, and an electronic device (wristwatch) which uses such switch device.