The present invention provides apparatuses and methods for controlling the brightness of a display unit based on detected movement of an external object such as a user. An apparatus includes a display, e.g., a color liquid crystal display (LCD) or organic light emitting diode (OLED). A proximity circuit generates a transmitted signal and a received signal. The received signal results from the transmitted signal being reflected by an external object. A control unit processes the received signal to determine a degree of motion of the external object. When the degree of motion is greater than a first predetermined threshold but not greater than a second predetermined threshold, the display is activated and operating at partial intensity. When the degree of motion is greater than the second predetermined threshold, the display is activated at full intensity. The degree of motion may be determined from the variation of the received signal.