Liquid crystal display including sensing unit for compensation driving

A liquid crystal display comprising:

• a plurality of gate lines which transfer a plurality of gate signals;
• a plurality of data lines which transfer a plurality of data signals;
• at least one dummy data line which transfers at least one test data signal;
• a data driver which generates and outputs the plurality of data signals;
• a gate driver which generates and outputs the plurality of gate signals;
• a plurality of pixels, each of which comprises a switching element having a control terminal and an input terminal connected to a corresponding gate line of the plurality of gate lines and a corresponding data line of the plurality of data lines, respectively;
• at least one test pixel comprising at least one test switching element having a control terminal connected to a corresponding at least one gate line of the plurality of gate lines;
• a sensing unit which measures a leakage current flowing through the test switching element and controls compensation driving of a threshold voltage of the switching element according to the measured leakage current;
• and
• a selection unit which selects one of the sensing unit and the dummy data line,
• wherein the selection unit connects an input terminal of the test switching element to the dummy data line when the liquid crystal display is driven, and connects the input terminal of the test switching element to the sensing unit when the liquid crystal display is not driven.