An improved driving device for a display panel. The insulative housing has a base portion and four peripheral walls extending upwardly from the base portion. Based on the detected motion information, by moving a digital watermark pattern to follow a picture, the digital watermark information can be superimposed on an input digital video signal so as to match human visual characteristics by using a technique such as emphasizing a portion on which the human eye is easily turned. The piston includes a flow past arrangement, which includes an opening and a cover. Accordingly, the homogeneity of the quality of an image is improved, and the operating speed of a driver circuit portion is enhanced.