A display device comprising: a display region comprising: a first pixel region; and a second pixel region and a third pixel region, wherein the second pixel region is disposed at a left upper end of the first pixel region and the third pixel region is disposed at a right upper end of the first pixel region, a dummy region comprising a first dummy region disposed between the second pixel region and the third pixel region, wherein the first dummy region is a non-display region that does not include any pixel; first pixels, second pixels, and third pixels respectively arranged in the first pixel region, the second pixel region, and the third pixel region, the first pixels, the second pixels, and the third pixels are disposed in a matrix of vertical lines and horizontal lines; comprising: a data converter configured to: receive first image data (DATA1) comprising effective data corresponding to the display region and dummy data corresponding to the dummy region; and generate second image data (DATA2) by converting the first image data (DATA1); and a data driver configured to: generate a data signal corresponding to the second image data; and supply the data signal to the first pixels, the second pixels, and the third pixels, wherein the data converter is configured to convert a gray scale value of dummy data corresponding to at least one region of the first dummy region in the first image data (DATA1) into a predetermined first gray scale value, the first gray scale value being between a lowest gray scale value and a highest gray scale value characterized in that the first gray scale value is set as one of: a gray scale value of a data signal having an average voltage value of a voltage value of a data signal corresponding to the lowest gray scale value and a voltage value of a data signal corresponding to the highest gray scale value; and a gray scale value of a data signal having a voltage value closest to the average voltage value among a plurality of intermediate gray scale values between the lowest gray scale value and the highest gray scale value. a display region comprising: a first pixel region; and a second pixel region and a third pixel region, wherein the second pixel region is disposed at a left upper end of the first pixel region and the third pixel region is disposed at a right upper end of the first pixel region, a first pixel region; and a second pixel region and a third pixel region, wherein the second pixel region is disposed at a left upper end of the first pixel region and the third pixel region is disposed at a right upper end of the first pixel region, a dummy region comprising a first dummy region disposed between the second pixel region and the third pixel region, wherein the first dummy region is a non-display region that does not include any pixel; first pixels, second pixels, and third pixels respectively arranged in the first pixel region, the second pixel region, and the third pixel region, the first pixels, the second pixels, and the third pixels are disposed in a matrix of vertical lines and horizontal lines; comprising: a data converter configured to: receive first image data (DATA1) comprising effective data corresponding to the display region and dummy data corresponding to the dummy region; and generate second image data (DATA2) by converting the first image data (DATA1); and receive first image data (DATA1) comprising effective data corresponding to the display region and dummy data corresponding to the dummy region; and generate second image data (DATA2) by converting the first image data (DATA1); and a data driver configured to: generate a data signal corresponding to the second image data; and supply the data signal to the first pixels, the second pixels, and the third pixels, generate a data signal corresponding to the second image data; and supply the data signal to the first pixels, the second pixels, and the third pixels, wherein the data converter is configured to convert a gray scale value of dummy data corresponding to at least one region of the first dummy region in the first image data (DATA1) into a predetermined first gray scale value, the first gray scale value being between a lowest gray scale value and a highest gray scale value characterized in that the first gray scale value is set as one of: a gray scale value of a data signal having an average voltage value of a voltage value of a data signal corresponding to the lowest gray scale value and a voltage value of a data signal corresponding to the highest gray scale value; and a gray scale value of a data signal having a voltage value closest to the average voltage value among a plurality of intermediate gray scale values between the lowest gray scale value and the highest gray scale value. a gray scale value of a data signal having an average voltage value of a voltage value of a data signal corresponding to the lowest gray scale value and a voltage value of a data signal corresponding to the highest gray scale value; and a gray scale value of a data signal having a voltage value closest to the average voltage value among a plurality of intermediate gray scale values between the lowest gray scale value and the highest gray scale value.