Display device and method for controling brightness of images in display device

The present invention show that with a present invention is a pixel array and a backlight as to provide a display device that controls brightness of the backlight, for this purpose in accordance with the gradation level of the image data displayed in one image frame by frame panels and and, in a display device having a gate driver and a data driver for driving the display panel with a scanning signal and an image signal, a luminance calculator for receiving the first image data which is currently input calculating a first brightness average value, wherein: the first according to the brightness average and the previous to the first comparing the second brightness average value of the second image data input to the current backlight brightness control value and a brightness adjustment for adjusting the current contrast control value unit, the current backlight brightness control value and the backlight driver to adjust the current backlight driving signal provided to the back light, the current According to Trast adjustment value to adjust the contrast of the first image data to provide a display device having a contrast control unit to provide to the data driver. Display device, a backlight, the brightness adjusting signal, the contrast