專利摘要：
A method of producing a secondary lens with hollow nano structures comprises the following steps (a) forming a polycrystalline seed layer on the surface of a lens; (b) growing a plurality of nano-rod structures over the polycrystalline seed layer in a random arrangement; (c) removing the portion of the seed layer where the nano-rod structure does not grow so that the surface of the lens therebeneath is exposed to outside; (d) sputtering a ceramic material layer over the plurality of nano-rod structures and the exposed surface portion of the lens; (e) removing the plurality of nano-rod structures and leaving a ceramic material layer having a plurality of hollow nano-rod structures in a random arrangement. A layer with hollow nano structures is formed on the surface of a lens wherein the hollow nano structures have the effect of scattering light and can improve the uniform illuminance of a secondary lens.