Switch device and electronic instruments equipped with the switch device

摘要

When an electronic instrument has taken a predetermined attitude, an attitude-detecting switch (19) incorporated in the instrument detects the attitude, and outputs a switch signal to a CPU (15). The CPU (15), in turn, drives a lighting device (21) for lighting a liquid crystal display device (17). The lighting device (21) is driven, for example, only when a predetermined number of pulses of the switch signal are generated within a predetermined period of time, or only when the switch signal has continued for a predetermined period of time or more. Thus, there are cases where the lighting device (21) is not driven irrespective of the generation of the switch signal. As a result, the lighting device (21) is prevented from operating so often, and hence the life of its battery is lengthened. <MATH>