Study of the Optical Properties of Multi-Particle Phosphors by the FDTD and Ray Tracing Combined Method

Abstract

It is well known that the optical properties of multi-particle phosphor are crucial to the light performance of white light-emitting diodes (LEDs). Note that the optical properties including scattering or absorption properties for a single particle are easy to be calculated. However, due to the large computation considering the complicated re-scattering and re-absorption, it is difficult to calculate the scattering behaviors of the multi-particles. A common method to reduce the computation, which can cause unknown deviations, is to replace the multi-particle scattering properties by using the average scattering data of single particles. In this work, a cluster of multi-phosphor particles are directly simulated by the finite-difference time-domain (FDTD) method. The total scattering data of the cluster was processed as a bulk scattering parameter and imported to the Monte-Carlo ray-tracing (RT) method to realize a large-scale multi-particle scattering calculation. A polynomial mathematical model was built according to the multi-particle scattering data. An experiment was carried out for verifying the accuracy of the method in this work. The mean absolute percentages of the previous method are 1.68, 2.06, and 1.22 times larger than the multi-particle method compared with the experimental curves, respectively.

Recent Progress in Light‐Scattering Porous Polymers and Their Applications

“…LEDs (herein referred to as inorganic LEDs, i.e., GaN-based LEDs) and OLEDs suffer from limited efficiencies due to the large refractive index of their constituent materials compared to that of air. [93][94][95] A significant fraction of the internally generated light is trapped inside the devices due to the coupling to guided modes. By integrating scattering layers into LEDs or OLEDs, the trapped modes can be effectively extracted from the devices, contributing to a large enhancement of the efficiencies.…”

A Nonstandard Path Integral Model for Curved Surface Analysis

“…To evade these difficulties, an assortment of proficient techniques has been proposed (and summarized in [8]), ranging from curvilinear or nonorthogonal FDTD variations to modified Cartesian and conformal algorithms. Nonetheless, the research on this significant topic is constantly escalating, thus leading to various schemes which offer treatment to many contemporary applications from the microwave and optical regime [19][20][21][22][23][24][25][26][27][28][29][30][31] and paving the way to the trustworthy analysis of many future state-of-the-art scientific fields [32][33][34][35][36][37][38][39][40][41][42][43]. Therefore, the manipulation of arbitrarily-curved surfaces or material interfaces via a staircase model deteriorates the reliability of any FDTD-based approach and, particularly, of the NS-FDTD scheme, whose stencils must be very carefully selected.…”

Micro-Prism Patterned Remote Phosphor Film for Enhanced Luminous Efficiency and Color Uniformity of Phosphor-Converted Light-Emitting Diodes

“…White light-emitting diodes (WLEDs) are very promising light sources in general lighting, automotive headlamp, and liquid-crystal backlight due to their high efficiency, long lifetime, compact size and environmental friendliness [ 1 , 2 , 3 ]. The most widely used configuration to generate white light is the combination of a blue GaN chip and down-converted yellow phosphor, namely phosphor-converted light-emitting diodes (pc-LEDs), which has excellent durability, low cost and easy scalability [ 4 , 5 , 6 ]. It is well known that luminous efficiency (LE) and color uniformity (CU) are two important indexes of pc-LEDs [ 7 , 8 , 9 ].…”