Apparatus for testing display device and display device for performing mura compensation and mura compensation method

A display device comprising:

• a display panel comprising a plurality of pixels connected to a plurality of data lines and a plurality of scan lines;
• a data driving circuit configured to drive the plurality of data lines;
• a scan driving circuit configured to drive the plurality of scan lines;
• a memory configured to store compensation data;
• and
• a driving controller configured to receive a control signal and an input image signal, control the data driving circuit and the scan driving circuit to display an image on the display panel, and provide, to the data driving circuit, an image data signal obtained by correcting the input image signal based on the compensation data,
• wherein the compensation data comprises a main compensation coefficient for a main gradation, a representative value for the main gradation, a representative value for a sub gradation, and a flag and a compensation value for the sub gradation.

A method comprising:

• receiving a detected image signal for a main gradation and determining a main compensation coefficient for the main gradation;
• receiving the detected image signal for a sub gradation and determining a sub compensation coefficient for the sub gradation;
• performing primary prediction by dividing a display panel into a plurality of blocks, determining a representative value for each of the plurality of blocks, and determining a prediction compensation coefficient for the sub gradation based on the representative value and the main compensation coefficient;
• performing secondary prediction by determining a flag based on the sub compensation coefficient and the prediction compensation coefficient;
• providing compensation data comprising the main compensation coefficient, the representative value, and the flag;
• and
• providing an image signal that is obtained by correcting an input image signal based on the compensation data and displaying an image based on the image signal.