In a method of manufacturing a display apparatus, the method includes: providing a first mother substrate; forming, on the first mother substrate, a pixel layer comprising a light-emitting device; providing a second mother substrate; forming, on the second mother substrate, a diffraction pattern layer configured to diffract light emitted from the light-emitting device; forming a bonded substrate structure by bonding the first mother substrate, on which the pixel layer is formed, and the second mother substrate, on which the diffraction pattern layer is formed; forming, by cutting the bonded substrate structure, a plurality of unit substrate structures each comprising a first substrate on which the pixel layer is formed and a second substrate on which the diffraction pattern layer is formed; forming a protection member on the diffraction pattern layer; and removing a foreign material on the diffraction pattern layer with the protection member.