The present invention provides an optical sheet having a plurality of light guide plate patterns, each light guide plate pattern having a micro-patterned output surface for emitting light, and a micro-patterned bottom surface opposing to the output surface. The optical sheet is made in steps comprising: extruding a resin into the nip between a patterned roller and a patterned carrier film at a patterned roller temperature T1 and a nip pressure P1, to form the optical sheet, the optical sheet having a first patterned surface and a second patterned surface, the first patterned surface having a micro-pattern transferred from the patterned roller and the second patterned surface having a micro-pattern transferred from the patterned carrier film; and peeling off the patterned carrier film from the optical sheet.