Patent ID: 7489325

Claim:
A display device comprising: a maximum/minimum value detection portion for receiving an input signal, and for extracting the maximum value (MAX) and the minimum value (MIN) of an input signal for at least one frame; a signal level detection portion which provides a classification result based on the extracted values MIN and MAX; a signal determination portion which provides a gain, a classification, and a set value, in response to the classification result; a signal level control portion for receiving the gain and the classification, and for outputting a modulating voltage; a data driver for receiving the modulating voltage and driving at least one data electrode; a threshold voltage control portion for receiving the set value, and for determining a threshold voltage; and a scanning driver for receiving the determined threshold voltage, and for driving at least one scanning electrode, wherein: the classification result is one of: A, B, C, and D; standard values comprise: a minimum value minA, a maximum value maxA, a minimum value minC, and a maximum value maxC; the standard values satisfy 0=minA<minC<maxA<maxC=maximum signal; and the signal level detection portion is configured to determine the classification result as follows: (i) the classification result is B if minC≦(MIN and MAX)≦maxA, (ii) if the classification result is not B, then the classification result is A if minA≦(MIN and MAX)≦maxA, (iii) if the classification result is not B, then the classification result is C if minC≦(MIN and MAX)≦maxC, and (iv) if the classification result is not B, and the classification result is not A, and the classification result is not C, then the classification result is D.