- Researchers build next-generation display integration technology using domestic materials, components and equipment

- Panel applicability tests boost prospects for commercializing the technology

ETRI researchers who developed the single-substrate stacked QD-OLED technology. [Courtesy of ETRI]
ETRI researchers who developed the single-substrate stacked QD-OLED technology. [Courtesy of ETRI]

The Electronics and Telecommunications Research Institute (ETRI) has developed a QD-OLED panel technology that stacks an OLED light-emitting layer and a quantum dot color-conversion layer on a single substrate, working with domestic materials, components and equipment companies.

The technology reduces the limitations of the conventional two-substrate bonding structure, raising the prospect of producing next-generation displays that are thinner and more precise.

Current commercial QD-OLED panels typically use a structure in which a blue OLED light-emitting substrate and a QD color-conversion substrate are manufactured separately and then bonded together.

That approach requires a filler layer between the two substrates and adds substrate alignment and bonding steps, increasing both panel thickness and manufacturing complexity.

To address these limitations, the research team formed a thin-film encapsulation layer over the blue OLED light source, then stacked a black pixel-definition layer and a QD color-conversion layer directly on top.

The approach confirmed the process feasibility of fabricating the OLED light-emitting layer and the QD color-conversion layer consecutively on a single substrate, without attaching a separate QD substrate.

The team achieved 184,800 subpixels on a 6-inch substrate at a pixel density of 141 pixels per inch — a level of integration comparable to that required for a 65-inch 8K television.

ETRI researchers analyze the inkjet printing process for a single-substrate stacked QD-OLED panel. [Courtesy of ETRI]
ETRI researchers analyze the inkjet printing process for a single-substrate stacked QD-OLED panel. [Courtesy of ETRI]

The achievement is significant because it advances the prospects for commercializing next-generation QD-OLED integrated processes using domestically sourced materials, components and equipment.

The technology is expected to find applications not only in large premium displays but also in mixed reality and extended reality displays, where thin form factors and high pixel density are essential.

"This research combines industrial inkjet printing technology with a QD color-conversion layer and a black pixel-definition layer stacked pixel structure to chart an industrial direction for next-generation QD-OLED," said Kwon Byung-hwa, a researcher at ETRI's Realistic Display Research Laboratory. "Having secured a full-cycle technology base spanning materials, processes and panel fabrication, we expect this work to help establish an early position in the ultra-high-resolution mixed reality and extended reality display market."

ETRI plans to advance the single-substrate stacked QD-OLED technology further, with the goal of contributing to market leadership in both large premium displays and ultra-high-resolution displays for mixed reality and extended reality applications.

The findings were published in Chemical Engineering Journal, an international peer-reviewed journal in the field of chemical engineering.


nbgkoo@heraldcorp.com