Patent ID: 8330747

Claim:
A display device comprising: a first detection element that detects a light amount of outside light; a second detection element that detects a dark current arising when the outside light is blocked; selection means for selecting either one of the first detection element and the second detection element; a comparator that compares an output of the first detection element and the second detection element selected by the selection means with a predetermined reference value time divisionally, where a first amount of time is measured from a detection start of the first detection element to a time at which a detection value of the first detection element exceeds the predetermined reference value and said first amount of time is stored as a first comparison result, and a second amount of time is measured from a detection start of the second detection element to a time at which a detection value of the second detection element exceeds the predetermined reference value and said second amount of time is stored as a second comparison result; and control means for calculating a difference between the first comparison result obtained by the comparator when the first detection element is selected by the selection means and the second comparison result obtained by the comparator when the second detection element is selected, and controlling an amount of light supplied to the display area depending on a calculation result.