High Accuracy Optical Metrology for MicroLED Displays and Wafers
2025/10/16
MicroLED mass production demands both speed and accuracy. In this article, Dr. Tobias Steinel presents a novel metrology approach that merges high-resolution imaging with live spectroradiometer calibration. The method achieves per-emitter spectral precision and reduces test times from hours to minutes — a breakthrough for µLED wafer and display testing.
The research demonstrates that traditional LIV measurements with integrating spheres are too slow for mass testing. By contrast, the proposed LumiTop system performs live spectral calibration for every image, adapting automatically to wavelength variations caused by process tolerances or drive conditions. Tests on a 6-inch wafer with 17 million µLEDs were completed in about five minutes, with results matching spectroradiometer-only measurements within one color point.
An advanced Single Pixel/Emitter Evaluation (SPE) algorithm provides per-emitter data such as dominant wavelength, luminance, and chromaticity. In addition, the newly introduced optimized stepped-kernel filter effectively removes sampling artefacts at low oversampling ratios (Rs = 2–5), improving spatial accuracy without increasing imaging time.
The combination of imaging and spectroradiometric methods enables traceable, high-speed wafer and display testing, balancing measurement speed with spectral precision. This hybrid approach supports yield improvement, uniformity correction, and reliable calibration for mass production of MicroLED displays.
- Read the full article on TechBlick:
https://www.techblick.com/post/high-accuracy-optical-metrology-for-microled-displays-and-wafers - Learn more in the full presentation on YouTube:
https://youtu.be/dQu_6RN2VDE?si=6yFx--YdysMKVWuv