Patent ID: 7884810

Claim:
An unevenness detecting apparatus for compensating a threshold voltage variation including a plurality of scan lines and a plurality of data lines; and a pixel circuit arranged on each point which the scan lines and the data lines are intersected, wherein the pixel circuit includes: a sensing electrode having one terminal; a first transistor having a gate terminal connected to a scan line [Gate n], a source terminal connected to the data line and a drain terminal; a second transistor of which a gate terminal is connected to a scan line [Gate n−1] of a former pixel row, a source terminal is directly connected to the drain terminal of the first transistor, and a drain terminal is connected to the terminal of the sensing electrode; a third transistor of which a gate terminal is connected to the sensing electrode and the drain terminal of the second transistor, a drain terminal is connected to the scan line [Gate n], and a source terminal is connected to the drain terminal of the first transistor and the source terminal of the second transistor; a fourth transistor of which a gate terminal and a drain terminal are connected to the scan line [Gate n−1] of the former pixel row, and a source terminal is connected to the drain terminal of the second transistor, the sensing electrode and the gate terminal of the third transistor; and a capacitor of which one terminal is connected to a gate terminal of the third transistor, a drain terminal of the second transistor, a source terminal of the fourth transistor, and the sensing electrode, and the other terminal is connected to the scan line [Gate n].