| 摘要 |
PROBLEM TO BE SOLVED: To overcome the problem of a prior art such that a battery becomes consumed easily, without making any telephone call since a current as large as a current consumed in a telephone call is consumed, when a back light is used for even a keyboard, in addition to the backlight of an LCD display part and the LCD back light and keyboard backlight are on during normal operation. SOLUTION: The portable telephone device has a display operation part 4 which is pressed to set a function, the LCD display part 1 which displays the setting state during the operation of the portable telephone, a display operation part 4, the key backlight part 8 for making the LCD display part 1 easy to see even at night, and the LCD backlight part 6. The voltage applied to the LCD backlight part 6 and key backlight part 8 are related and varied, so that when the LCD backlight part 6 is set light, the key backlight pr at 8 becomes dark associatively. |
