A display device includes a substrate, a cover layer, liquid crystal, electrodes, and a sealant layer. The cover layer is disposed on the substrate and defines at least a portion of a tunnel-shaped cavity. The liquid crystal is disposed in the tunnel-shaped cavity. The electrodes are disposed on the substrate and are configured to apply an electric field to the liquid crystal. The sealant layer is disposed on the substrate and is configured to seal the tunnel-shaped cavity. The cover layer includes a first insulating layer including a concave-convex surface.