Design of a diffuser plate with micro-structures for direct type LED backlight

The diffuser plate is the key component of the direct type LED backlight module. The design of the micro-structures on the surface of the diffuser plate is the critical factor in manufacturing diffuser plate of good optical properties. A mathematical model for direct type LED backlight is built. The size and arrangement of micro-structures are simulated using Lighttools software based on a Monte Carlo ray tracing. The influence of the magnitude and arrangement of semisphere or V Cut on the optical properties of the diffuser plate is analyzed by using this method. For the diffuser in this experiment, the optical properties are best when the semisphere radius is fixed at 0.1 mm and the center distance between two adjacent semispheres are 0.6 mm; for the V-Cut micro-structures, the optical properties are best when the distance between two adjacent V-Cut grooves is 0.4 mm and the vertex γ is 110°. The results lay a theoretical basis for improving the optical properties of the direct type LED backlight.