Display device and processing method of image signal thereof

The present invention relates to a liquid crystal display device and a method of processing an image signal thereof. A method of processing the image signal of a liquid crystal display device according to an embodiment of the present invention includes a step of receiving a previous image signal which is two continuous input images and a present image signal, a step of generating a flag with regard to a brightness change condition by comparing the previous image signal and the present image signal, a step of generating the correction image signal of doubled frames with regard to the present image signal by performing a first correction and doubling process on the present image signal, and a step of generating a final correction image signal by performing a post process on the correction image signal of some frames among the doubled frames by using the flag.