Design and production of a free form lens for long-range illumination

In this study, we design and manufacture new prototype of a LED Projector containing Free Form Lenses to cover both visible and infrared regions for the long-range illumination. The geometrical form of the lens is obtained by minimizing the optical path length for the light rays emitted from LED. The lens is produced by the plastic injection method using PMMA material whose transmittance for the concerned optical region is greater than 90%. The optical measurements of the lens is compared with the simulation based on ZEMAX 2009. It is found that, although there are some production errors and LED alignment problems, the optical measurements of the lens are close to the predicted values in the design.