Optical flux partition method for high uniformity illumination of a refractive lens

A design strategy for refractive lenses is presented that offers both high uniformity illumination and good directivity. Its main feature is to divide the incident optical flux and assign each portion to a calculated area based on the illuminance required. This scheme uses simple photometry and geometrical optics without resorting to partial differential equations or iterative algorithms. The simulation results show that the uniformity of the illumination can reach over 80%, and the diverging angle can be less than 3° for an appropriate partition number.