Patent ID: 8325129

Claim:
A liquid crystal display, comprising: a back light assembly that emits light on a liquid crystal panel; a duty ratio controller that controls a duty ratio of a driving control signal according to the difference between video data of at least three frames that are sequentially inputted to the liquid crystal panel; and an inverter that controls brightness of the light emitted from the back light assembly according to a difference between video data of at least three frames that are sequentially inputted to the liquid crystal panel, wherein the inverter supplies a back light driving signal to the back light assembly to change the brightness of the light emitted from the back light assembly according to the duty ratio of the driving control signal, wherein the duty ratio controller includes a comparing part that compares video data of at least three frames that are sequentially inputted to the liquid crystal panel and a duty ratio control signal generator to generate a duty ratio control signal having a duty ratio calculated in response to a comparison result of the comparing part, and a look up table that is set such that quantities of change of video data between at least three frames and duty ratios are corresponded to each other, wherein the comparing part generates an image change detection signal indicating a change of an image between video data of at least three frames according to the comparison result and supplies the image change detection signal to the duty ratio control signal generator, wherein the duty ratio control signal generator achieves the duty ratio corresponding to the comparison result from the look up table by the image change detection signal, wherein the duty ratio control signal generator counts the number of changes between the two consecutive frames among the at least three sequentially inputted frames by the image change detection signal, wherein the duty ratio control signal generator achieves the duty ratio corresponding to the counted number of changes that represents a quantity of change of video data from the look up table and supplies the achieved duty ratio to the inverter.