An optical lens (10) includes an array of lens units (11). Each lens unit includes a main body (101), a light diverging portion (112) and a light converging portion (114). The main body includes a light incident surface (110) and a light emitting surface (112) opposite to the light incident surface. The light diverging portion is used to expand a light field along an x-direction. The light converging portion is used to compress a light field along a y-direction. In specific embodiments, the light diverging portion and the light converging portion are respectively formed on the light incident surface and the light emitting surface.