An array substrate including a plurality of pixel regions transmitting light includes a switching element disposed in each of the pixel regions defined by gate and source lines, wherein the switching element is electrically connected to the gate and source lines, a pixel electrode electrically connected to the switching element, a first insulating layer disposed on the switching element, and a second insulating layer disposed under the first insulating layer, wherein a thickness of the second insulating layer is dependent on a peak wavelength of red light.