Abstract: In a display device, the display device includes a substrate, a red color filter layer, a green color filter layer, and a blue color filter layer. The substrate has red, green and blue sub-pixel regions. The red color filter layer is located on the red, green and blue sub-pixel regions, and has a first opening formed in the green sub-pixel region and a second opening formed in the blue sub-pixel region. The green color filter layer is located in the first opening. The blue color filter layer is located in the second opening. Since the red color filter layer is used as an interlayer insulating layer, there is no need to perform a separate process to form a color filter layer and a process for an interlayer insulating layer can be omitted. Thus, it can simplify a process.