Liquid crystal display device with adaptive charging/discharging time and related driving method

A liquid crystal display device includes a plurality of gate lines, a plurality of data lines, a pixel array, a gate driver, a timing controller, and an optimization circuit. Each pixel unit in the pixel array displays images according to the gate driving signal received from a corresponding gate line and the data driving signal received from a corresponding data line. According to an optimized reference value, the timing controller provides an output enable signal, based on which the gate driver outputs the gate driving signals. The optimization circuit receives a first grayscale data related to display images of a row of pixel units in a first driving period and a second grayscale data related to display images of the row of pixel units in a second driving period, and provides the optimized reference value according the difference between the first and second grayscale data.