Fang Professor of Engineering & Chair Professor, Department of Electronic & Computer Engineering,
Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Professor Kei May Lau is the Fang Professor of Engineering at the Hong Kong University of Science and Technology (HKUST). She received the B.S. and M.S. degrees in physics from the University of Minnesota, Minneapolis, and the Ph.D. degree in Electrical Engineering from Rice University, Houston, Texas. She was on the ECE faculty at the University of Massachusetts/Amherst and initiated MOCVD, compound semiconductor material and device programs. Since the fall of 2000, she has been with the ECE Department at HKUST. She established the Photonics Technology Center for R&D effort in III-V materials, optoelectronic, high power, and high-speed devices. Professor Lau is a Fellow of the Hong Kong Academy of Engineering Sciences, IEEE and OSA, a recipient of the US National Science Foundation (NSF) Faculty Awards for Women (FAW) Scientists and Engineers (1991), Croucher Senior Research Fellowship (2008), and the IEEE Photonics Society Aron Kressel Award (2017). She was an Editor of the IEEE TED, EDL, Applied Physics Letters and Journal of Crystal Growth.
Monolithic micro-LED micro-displays
Abstract:Mature LED technologies for large area LED displays and general lighting are now commonplaces. Miniaturization of LEDs for micro-displays is attracting much attention aiming at the direct view or projection applications.Consumer market sectors such as AR, VR, and head-up displays are constantly searching for various display options. GaN-based LEDs have advantages in terms of efficiency, brightness, lifetime, temperature stability and robustness, compared with other existing micro-display technologies. The most significant is visibility under bright day-light.
Fabrication of high resolution truly monolithic micro-display with decent visual quality is challenging.We have developed different approaches of bumping technology in flip-chip bonding to demonstrate cost-effective high resolution monochromatic micro-displays with good bonding yield.Realization of full color LED micro-display remains the biggest challenge because it is not practical to selectively grow three different epi-layers emitting at different wavelengths on a single substrate for the three primary colors. For near-to-eye display application, Quantum dots were used for color conversion on micro-LED array, achieving full color LED micro-displays with high image quality.
To maximize the throughput and minimize the light-guiding effect of the transparent sapphire substrate leading to pixel crosstalk, we have also used LED epilayers grown on Si substrates that can be removed using a simple and low-cost SF6-based RIE etching process. AMLED micro-displays combining a micro-LEDs array using GaN-on-Si epilayers and a CMOS driver will be introduced.