Design of Collimating Lens with Multiple Freeform Surfaces Based on Total Internal Reflection Structure

In this study, a multi-freeform collimating lens is designed based on a total internal reflection structure to effectively obtain a wide range of emitted light from the semiconductor light-emitting diodes to ensure efficient use of light energy. The initial structure of this type of lens is based on Snell's law and is designed using algorithms based on optical principles such as the law of conservation of energy. The initial structure of the lens is imported into the Creo software. Subsequently, a 360 degrees rotation is performed to obtain a three-dimensional solid model. The obtained structure is transferred to the TracePro optical software for Monte Carlo ray tracing simulation. A circle spot is obtained at a distance of 20 m from the receiving board. Further, the normal vector of the lens model is corrected. The optimized lens exhibited light transmittance up to 182 cd/lm and a beam angle of +/- 1.621 degrees after the simulation. Compared with the traditional total internal reflection structure lens, the optimized lens exhibits an improved ability to control narrow beams.