Embodiments are directed to a method of manufacturing a display device, including preparing a pixel circuit substrate including thin-film transistors and pixel electrodes respectively electrically connected to the thin-film transistors, forming a first deposition layer on the pixel circuit substrate using a first mask assembly, and forming a second deposition layer on the pixel circuit substrate using a second mask assembly. At least one of the first mask assembly and the second mask assembly includes a mask plate including an opening portion through which a deposition material passes and a covering portion that blocks a passage of the deposition material. The mask plate includes a protruding portion that protrudes from an edge of the covering portion toward a center region of the opening portion.

The first mask assembly may include a mask sheet including a plurality of holes spaced apart from each other. The mask plate of the first mask assembly may partially cover a first hole among the plurality of holes.

The mask plate of the first mask assembly may overlap the mask sheet and may be arranged in a direction intersecting an extending direction of the mask sheet.

The first deposition layer may include emission layers spaced apart from each other. A shape of each of first emission layers among the emission layers formed on the pixel circuit substrate may be different from a shape of each of second emission layers among the emission layers.

The organic light-emitting display device may include a transmissive area through which light or sound is transmitted, a display area that partially surrounds the transmissive area, and a non-display area between the transmissive area and the display area. The first emission layers may correspond to the display area, and the second emission layers may correspond to the non-display area.