Optical substrate and display device

A display device, comprising:

• an optical substrate;
• and
• an opposing substrate opposite to the optical substrate,
• wherein the optical substrate comprises a light guide plate and a plurality of light selection units, the light guide plate comprises a light-incident surface and a light-exiting surface, and the light-exiting surface comprises a plurality of light-exiting regions;
• each light selection unit of the plurality of light selection unit is configured to select light incident from the light-incident surface and propagating in the light guide plate, such that monochromatic light of different colors are emitted from multiple light-exiting regions corresponding to the each light selection unit, and each of the multiple light-exiting regions emits monochromatic light of a single color.