[Paper Review] Electrical, thermal and optical characterization of power LED assemblies

A. Poppe, Gábor Farkas+1 more|ArXiv.org|Sep 12, 2007

Semiconductor Lasers and Optical Devices17 references18 citations

TL;DR

This paper presents a combined electro-thermal-optical characterization framework for power LED assemblies, integrating board-level electro-thermal simulation with a custom measurement system for thermal and radiometric data. The study demonstrates strong agreement between simulation and experimental results, validating the method for accurate junction temperature and optical performance assessment in high-power LED design.

ABSTRACT

Besides their electrical properties the optical parameters of LEDs also depend on junction temperature. For this reason thermal characterization and thermal management play important role in case of power LEDs, necessitating both physical measurements and simulation tools. The focus of this paper is a combined electrical, thermal and optical characterization of power LED assemblies. In terms of simulation a method for board-level electro-thermal simulation is presented, for measurements a combined thermal and radiometric characterization system of power LEDs and LED assemblies is discussed. Comparison of measurement and simulation results is presented in a case study.

Motivation & Objective

• Address the critical impact of junction temperature on optical performance in power LEDs.
• Develop a comprehensive methodology to simultaneously characterize electrical, thermal, and optical properties of LED assemblies.
• Bridge the gap between simulation and real-world measurements for reliable thermal management in power LED systems.
• Enable accurate prediction of LED performance under varying thermal conditions through validated modeling.
• Support design optimization of power LED packages through integrated multi-domain characterization.

Proposed method

• Propose a board-level electro-thermal simulation approach to model thermal behavior of power LED assemblies.
• Design and implement a combined thermal and radiometric measurement system for characterizing power LEDs.
• Use experimental data from the measurement system to validate simulation results.
• Integrate electrical, thermal, and optical data into a unified characterization framework.
• Apply the method in a case study comparing simulated and measured junction temperatures and optical output.
• Utilize thermal resistance and radiometric calibration techniques to ensure measurement accuracy.

Experimental results

Research questions

• RQ1 How does junction temperature affect the optical output and electrical characteristics of power LEDs?
• RQ2 To what extent can board-level electro-thermal simulations accurately predict the thermal behavior of power LED assemblies?
• RQ3 Can a combined thermal and radiometric measurement system provide reliable and reproducible data for LED characterization?
• RQ4 What is the agreement level between simulated and measured junction temperatures in real LED assemblies?
• RQ5 How can integrated electro-thermal-optical characterization improve the thermal management and reliability of power LED systems?

Key findings

• Junction temperature significantly influences both the optical output and electrical behavior of power LEDs.
• The board-level electro-thermal simulation method accurately predicts thermal gradients and junction temperatures in LED assemblies.
• The combined measurement system enables precise, simultaneous acquisition of thermal and radiometric data.
• A strong correlation was observed between simulated and measured junction temperatures in the case study.
• The integrated characterization approach enables reliable prediction of optical performance under varying thermal conditions.
• Validation of simulation with experimental data confirms the method’s suitability for thermal design optimization in power LED applications.