The disclosure provides a display device including an upper substrate (001) and a lower substrate (002) arranged opposite to each other, a liquid crystal layer (003), a wave guiding layer (004), electrode structures (005), and a collimated light source (006). The liquid crystal layer (003) is arranged between the upper substrate (001) and the lower substrate (002); the wave guiding layer (004) is arranged on a side of the lower substrate (002) facing the upper substrate (001), and a refractive index of the wave guiding layer (004) is at least greater than a refractive index of a film layer in contact with the wave guiding layer (004); the plurality of electrode structures (005) are arranged on a side of the upper substrate (001) facing the lower substrate (002), and the plurality of electrode structures (005) are arrayed in correspondence to sub-pixels in a one-to-one manner; and the collimated light source (006) is at least arranged on one side of the wave guiding layer (004). The display device can control a display grayscale.