Ambient contrast ratio of quantum-dot color-converted micro-LED displays

Pixelated quantum dot color conversion layer (PQDCCL) is the most promising approach to realize a full-color micro-LED display. However, the QD excitation by ambient light has non-negligible impact on the ambient contrast ratio (ACR) and the display readability, and the ACR issue of color-converted micro-LED display has not been fully explored before. In this paper, the theoretical models of unpixelated monochromatic and pixelated polychromatic QDCCLs (UP/PQDCCL) are established to quantificationally analyze the ACR of a micro-LED display, which is further demonstrated by both ray-tracing simulation and experimental test. The simulation and theoretical results are highly consistent, and the average deviation is only 6.73%. In terms of experimental verification, the ACR indices are between 19.90 and 36.20 for the prepared UP/PQDCCLs that are obtained by photolithography technique and measured under the indoor ambient light of 500 lx and the luminance of the micro-LED screen of 1000 nits. The experimental, simulation, and theoretical results are fully compared and analyzed to show the application prospect of the proposed model in QD-based micro-LED displays. More importantly, this model could provide theoretical support and proof for the ACR estimation of self-luminous color-converted displays.

Automated summary

Pixelated quantum dot color conversion layer (PQDCCL) is a promising approach for full-color micro-LED displays. However, the QD excitation by ambient light affects the contrast ratio and readability of the display, and this issue has not been fully explored. This paper establishes theoretical models to analyze the contrast ratio of a micro-LED display and validates it through simulation and experiments. The results show the potential of the proposed model for QD-based micro-LED displays and provide support for estimating the contrast ratio of self-luminous color-converted displays.