A method of aligning a light emitting element includes providing an ink comprising light emitting elements on a substrate, a first electrode and a second electrode being disposed on the substrate and spaced apart from each other, and applying an AC voltage to the first electrode and the second electrode. The AC voltage is controlled so that a maximum value of an output AC voltage between the first electrode and the second electrode is higher than a first threshold voltage and a minimum value of the output AC voltage has a magnitude higher than a second threshold voltage, and the first threshold voltage and the second threshold voltage have a same magnitude and opposite polarities.