The present invention provides a light guide plate having an input surface for receiving light from a light source, a micro-patterned output surface for emitting light, and a micro-patterned bottom surface opposing to the output surface, made in steps comprising: extruding a resin into the nip between a patterned roller and a patterned carrier film at a nip pressure P1, to form an 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, peeling off the patterned carrier film from the optical sheet; and cutting and finishing the said optical sheet into a plurality of double-sided light guide plates having the specified length and width dimensions.