The present invention relates to a scroll pump with two scrolls that are co-operable for pumping fluid from an inlet to an outlet on relative orbiting motion of the scrolls. First, display image frames and display a first color to clean images of a preceding image frame between the displaying of two image frames. The substrate comprises an overlying first dielectric layer with an electrode embedded therein. The target assembly includes a first stage and a second stage. The assemblage has a space-saving configuration and a decreased difference between snapback voltage and breakdown voltage.