The liquid crystal display (LCD) device includes a LCD faceplate, a scan drive, a data drive, a driving controller, a light sensor, a light source, and a backlight drive circuit (BDC). The scan drive provides scan signal to the LCD faceplate. The data drive provides image signal to the LCD faceplate. The driving controller controls the scan drive, and the data drive to drive the LCD faceplate to display image. Sensing external light, the light sensor generates a light-sensing signal. BDC is in use for driving luminescence of the light source to provide light beam for the LCD faceplate. Receiving and recognizing the light-sensing signal, BDC can determine frequency and brightness of external light based on the light-sensing signal. Then, BDC controls luminescence brightness, and luminescence frequency based on frequency and brightness of external light. |