Open AccessDesigning double freeform surfaces for large ray bending irradiance tailoring of extended LED sources
Author(s) -
Yuyin Li,
Zexin Feng,
Dewen Cheng,
Yongtian Wang
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.423629
Subject(s) - irradiance , optics , ray tracing (physics) , computer science , simulated annealing , nonimaging optics , software , wavefront , bending , materials science , algorithm , physics , composite material , programming language
Many illumination applications require redistributing the irradiance distributions of LED sources with large ray bending. The problem becomes even more challenging for a compact design where the LED size is no longer ignorable. We tackle this problem by simultaneously designing two freeform optical surfaces. An iterative wavefront tailoring (IWT) method is adapted for obtaining the entrance and exit base freeform surfaces with a predefined ray bending regulation under stereographic coordinates (u, v). The simulated annealing (SA) algorithm is employed for deforming the two base freeform surfaces using the 'uv' polynomials with the purpose of minimizing the relative root-mean-square deviation (RRMSD) between the simulated irradiance distribution and the prescribed one. The optimizations are implemented in an automated workflow which links the optimization engine, 3D modeling software and ray tracing software. The effectiveness of the proposed method is illustrated by designing several double-freeform-surface lenses (central heights: 10 mm) with different ray bending regulated base surfaces and 10-th order uv polynomial departures for generating 500 × 200 mm 2 uniform irradiance distributions at a distance of 100 mm from 2 × 2 mm 2 and 3 × 3 mm 2 sources, respectively.