An element substrate is provided, including a substrate, a metal layer, a planarization layer and a first conductive layer. The metal layer is disposed on the substrate. The planarization layer is located on the metal layer, wherein the planarization layer includes a contact hole, the contact hole has a continuous wall and a bottom, the bottom exposes the metal layer, and the bottom of the contact hole has a first width. The first conductive layer is located on the planarization layer, wherein the first conductive layer includes an opening, the opening exposes the contact hole, and the opening has a second width above the contact hole, wherein the relationship of the first width and the second width is modified to decrease illumination loss and to prevent problems of shot-circuiting and insufficient capacitance.