A method for making a retarder includes: (a) forming a photocurable layer on a substrate, the photocurable layer including at least one photocurable prepolymer that has a plurality of reactive functional groups and a functional group equivalent weight ranging from 70 to 700 g/mol; (b) covering partially the photocurable layer using a patterned mask; (c) exposing the photocurable layer through the patterned mask; (d) removing the patterned mask; (e) exposing the photocurable layer to cure second regions of the photocurable layer so as to form a microstructure; (f) forming an alignment layer on the microstructure; (g) forming a liquid crystal layer on the alignment layer; and (h) curing the liquid crystal layer.