Abstract: A method of enhancing a contrast ratio of a picture of a display device, comprising steps of providing the display device having a light source; continuously receiving plural display signals; and turning off the light source when the display device has a buffer time during which each of the continuously received plural display signals has a picture brightness equal to zero.

Abstract: A controlling method of a display device includes the following steps. First, a time reference value, a plurality of preset period criteria and a plurality of operation mode data are stored in a memory unit, wherein each preset period criterion relates to each operation mode datum. Then, utilize a time controller to read the time reference value and a plurality of preset period criteria, compare the time reference value and a plurality of preset period criteria to determine the preset period criterion corresponding to the time reference value, and select the operation mode datum corresponding to the preset period criterion. Following that, utilize a micro-controller to set a plurality of setting values of the display device according to the operation mode datum selected by the time controller.