A display device comprises a data input unit configured to convert an image signal to a color signal. The display device also comprises a brightness control unit operationally coupled to the data input unit, configured to extract a brightness level associated with the color signal, to subdivide the brightness level associated with the color signal, and to apply different voltages according to brightness level subdivisions to control brightness of the color signal. The display device also comprises a display unit configured to display the color signal according to controlled brightness. The brightness level may comprise gray levels of a γ curve. The color signal may comprise one of YUV or RGB signals.