An optical plate includes a planar base and a plurality of rounded prisms formed on the planar base. The rounded prisms improve a uniformity of the light passing through the planar base and then irradiate the light having the improved uniformity. A concave peak formed in each of the plurality of rounded prisms of the optical plate scatters the light provided into a rear face of the optical plate so that dark lines and bright lines are not generated on the optical plate. As a result, the optical plate has improved light efficiency.