Asymmetric Quantum-Dot Pixelation for Color-Converted White Balance

Pixelated quantum-dot color conversion film (QDCCF) is attractive for next-generation, high-pixel-density, full-color displays. However, how to achieve white balance of these QD converted displays puts forward a new challenge, because the final light-emitting area is redefined by the apertures of the QD formed subpixels. Based on this, this paper presents an effective white-balance realization approach by precisely defining an asymmetric aperture ratio among three primary-color subpixels of the QDCCF. Based on the measured photoluminescence characteristic of quantum-dot photoresist (QDPR), the theoretical aperture ratio can be derived by the spectral radiation energy and external quantum efficiency (EQE) of QDCCFs for the target D65 white-balance state. A bilayered device architecture, combining a blue mini-LED backlight and a pixelated QDCCF, was simulated and experimentally assembled to verify the theoretical design. The simulated chromatic coordinates obtained from the QDCCF precisely agree with the target white-balance point. Experimental patterning and pixelation of the designed QDCCF were achieved by a precise photolithography process. Measured results show that a white-light output was achieved with the chromatic coordinates of (0.2822, 0.2951) and the color gamut of 115.09% NTSC (National Television System Committee) standard. The deviation of the experimental chromatic coordinates is within +/- 0.05 to the D65 standard light source. The proposed white-balance realization approach featured by the aperture adjustable subpixels of a chromatic QDCCF may open up a new route for color reproduction in emerging display technologies.