LED Junction Temperature Measurement: From Steady State to Transient State

Area of Science:

• Optoelectronics
• Thermal Management
• Semiconductor Devices

Background:

• Light-emitting diodes (LEDs) are critical components in modern lighting and electronics.
• Accurate junction temperature measurement is vital for LED performance, reliability, and lifespan.
• Advancements in LED technology necessitate sophisticated thermal characterization methods.

Purpose of the Study:

• To comprehensively review and analyze existing and emerging techniques for measuring LED junction temperature.
• To critically evaluate the advantages and limitations of various steady-state and transient thermal measurement methods.
• To provide insights into future trends and developments in LED thermal management.

Main Methods:

• Literature review and analysis of published research on LED junction temperature measurement techniques.
• Categorization of methods into steady-state and transient measurement approaches.
• Examination of techniques including micro-thermocouple, liquid crystal thermography (LCT), temperature sensitive optical parameters (TSOPs), infrared (IR) thermography, T3ster, continuous rectangular wave method (CRWM), thermal reflection imaging, and high-speed camera-based methods (h-SCRLI, μ_HSTI).

Main Results:

• Detailed summary of innovations in steady-state junction temperature detection, from 1D to 3D techniques.
• Comprehensive overview of transient junction temperature measurement methods, including established and novel approaches.
• Comparative analysis of the merits and demerits of diverse thermal measurement techniques for LEDs.

Conclusions:

• The review consolidates knowledge on LED junction temperature measurement, highlighting key advancements.
• Critical appraisal of current methods identifies areas for improvement and future research directions.
• Future developments are expected in high-speed, non-contact, and high-resolution thermal characterization of LEDs.