Non-edge ray reflector design for illumination systems

Nonimaging reflectors designed with rays other than the edge rays allow the designer to tailor the irradiance distribution at the target surface, especially for targets located at a finite distance from the source. An iterative approach of the development of the reflector shape allows for both uniform and asymmetric light distributions to be generated. The defining rays are chosen due to the characteristics of the prescribed source and the desired light distribution at the target, or in other words the final reflector design is dependent on the required application. Two-dimensional reflector (2D) shapes (i.e., troughs) are developed herein, but the method can be extended to three-dimensional (3D) reflectors (i.e., wells). Two examples employing specular reflectors for diode pumping of a solid-state laser rod are presented. These cases use a pseudo-imaging technique to direct the light to the preferred target. A final example develops a plastic lightguide that uses total-internal reflection (TIR) to obtain uniform illumination over a target plane.