Vol. 48, Issue 3, pp. 413-420

Vol. 48 Issue 3 pp. 413-420

Design of LED collimator for uniform illumination using two freeform lenses

Jiazhong Zeng, Xiufeng Li, Peng Ge


illumination design, lenses, light-emitting diodes, optical design, high uniformity


Regulating the illuminance distribution of an LED collimator to produce a uniform illumination in both the near field and the far field is a challenge in illumination design. In this paper, we present an effective method for designing two separated freeform lenses to control the illuminance distribution and the direction of the rays from the LED. The first lens redistributes the ray energy, and the second one collimates them to obtain a uniform collimated illumination. According to the conservation law of energy, Snell’s law, Fermat’s law and tangent-plane iterative method, the two freeform surfaces could be calculated simultaneously. The simulation results show that the two freeform lenses can control most of rays into an angle within ±1.5° for an LED with 1 × 1 mm size. The illuminance uniformities are higher than 0.9 in both the near field and the far field.

Vol. 48
Issue 3
Article No: 07
pp. 413-420

10.34 MB
OPTICA APPLICATA - a quarterly of the Wrocław University of Science and Technology, Faculty of Fundamental Problems of Technology