The application provides a mask disposed above a panel; the panel includes a planarization layer, and the planarization layer includes a plurality of trenches, the planarization layer is coated with a layer of TITO; the mask is provided with transparent regions, semi-transparent regions and opaque regions; the transparent regions are respectively arranged on the periphery of the display area and the semi-transparent regions are respectively arranged on the area directly above the trenches on the periphery of the display area; the opaque regions are respectively disposed directly above on each place other than the trenches of the panel, the transparent regions guide the light to expose and remove the TITO in the trenches on the periphery of the display area, the semi-transparent regions weaken the light and exposes and removes the TITO in trenches of the display area, the opaque regions block the light to avoid the exposure of TITO.