An active element (AE) layer includes: a substrate including an active body area and a protruding arm; an electrode, formed on the substrate and including an active region for sensing or actuation formed on the active body area of the substrate and a connection region formed on the protruding arm of the substrate, wherein the electrode includes a first indented line around the periphery of the active region, extending into the connection region and reaching two respective edges of the connection region, wherein the first indented line totally penetrates the electrode to make the respective edges electrically isolated; and an insulator layer formed on the electrode covering the active region and partially covering the connection region, wherein the insulator layer fills the indented line of the electrode.