Patent ID: 8872755

Claim:
A mobile electronic device comprising: a touch panel; an optical sensor operable to measure a surrounding brightness of the touch panel to provide a measured surrounding brightness; and a luminance control module operable to: maintain a luminance of the touch panel during a predetermined first time period starting when the measured surrounding brightness changes from a first condition to a second condition, during which the measured surrounding brightness decreases by an amount equal to or greater than a threshold value; maintain the luminance of the touch panel at a first luminance corresponding to the first condition when the measured surrounding brightness changes from the second condition to the first condition during the first time period; adjust the luminance of the touch panel to change to a second luminance corresponding to the second condition when the measured surrounding brightness has not changed from the second condition to the first condition during the first time period; and adjust the luminance of the touch panel to change to the second luminance corresponding to the second condition when there is no contact on the touch panel during a third time period corresponding to an initial portion of the first time period.