A method of manufacturing a display panel includes: preparing a support substrate including a first area and a second area that are spaced apart from each other, and a third area between the first area and the second area; forming, on the support substrate, a blocking layer located in the first area; forming, on the support substrate, a substrate material layer located in the first through third areas; removing a portion of the substrate material layer corresponding to the third area, to form a dummy substrate in the first area and a substrate in the second area; and separating the substrate from the support substrate, wherein the dummy substrate includes a plurality of protrusions protruding toward the substrate, and the substrate defines a plurality of through-portions corresponding to the plurality of protrusions, wherein an edge of each of the plurality of protrusions includes an uneven portion.