Holistic opto-thermal simulation framework for high-brightness light sources based on fluorescent conversion

António Correia,Peter Hanselaer,Youri Meuret

doi:10.1364/oe.27.0a1324

Abstract

Multi-physics approaches are increasingly adopted in the development of efficient, high brightness solid-state light sources, in particular for the realistic modelling of the fluorescent colour conversion element that is typically used to create white light. When a fluorescent material is excited by a high-power laser diode, it will self-heat and reach high temperatures. The efficiency or quantum yield of fluorescent materials lowers as their temperature increases, an effect called thermal quenching. The lower efficiency further increases the amount of phosphor self-heating which can lead to thermal runaway. This effect has been considered by different researchers when modelling the opto-thermal behaviour of the fluorescent colour conversion elements. However, other key fluorescent properties such as the absorption and emission spectrum also depend on temperature, and often also on the radiant flux density. This gives rise to a complex set of interplays between optical and thermal properties which are not considered in the current opto-thermal models but that significantly influence the performance of fluorescent material based solid-state light sources. In this work, we present a holistic opto-thermal simulation framework: a novel comprehensive simulation tool that includes all relevant multi-physics considerations. We show that the framework allows for an accurate and realistic prediction of the performance of high-luminance solid-state white light sources by comparing simulation results to experimentalmeasurements of a laser-based configuration, thereby validating the framework.

Highlights

The use of multi-physics approaches for the analysis of high-performance solid-state white light sources is a recent development in the field [1,2,3,4,5]
Multi-physics approaches are increasingly adopted in the development of efficient, high brightness solid-state light sources, in particular for the realistic modelling of the fluorescent colour conversion element that is typically used to create white light
The algorithms that were used are fully parallelized, the performance of the holistic optical and thermal simulation (hOTS) framework could be significantly increased if it would be deployed on a multi-CPU system

Summary

Introduction

The use of multi-physics approaches for the analysis of high-performance solid-state white light sources is a recent development in the field [1,2,3,4,5] These white light systems are typically designed by carefully simulating and optimizing their optical performance. Self-heating of the colour converting element (CCE) is generally a major bottleneck in achieving higher output optical power. This motivated the use of multi-physics modelling to study the effect of optical losses on the CCE’s temperature and how this effect impacts the performance of the light source [2, 8, 9]. By combining the optical and thermal properties in a single model it becomes possible to simulate the true optical performance of a high-power solid-state white light source much more accurately

Methods

Results

Conclusion