ELECTRONIC INFORMATION DEVICE AND POWER-SAVING METHOD IN ITS TELEPHONE DIRECTORY MODE, AND MOBILE PHONE AND POWER-SAVING METHOD IN ITS TELEPHONE DIRECTORY MODE

摘要

PROBLEM TO BE SOLVED: To provide an electronic information device that can display a telephone directory with priority even when a voltage of a built-in battery is dropped to some degree. SOLUTION: The electronic information device that is provided with a display device and the built-in battery and selected for a telephone directory mode or other modes, includes a power-saving device in the telephone directory mode. The power-saving device for the telephone directory mode is provided with a 1st discrimination means that discriminates whether or not the telephone directory mode is selected, a 2nd discrimination means that discriminates whether or not a voltage of the battery reaches a prescribed voltage or below, and a control means that shifts to the power saving telephone directory mode when the result of both the 1st and 2nd discrimination means indicates an affirmative result and stops functions except a function required for displaying a telephone directory on the display device.