25 - 27 August 2021 | Seoul
21st International Meeting on Informational Display
Imec will be present with 4 talks:
Paul Heremans - Perovskite light emitting diodes with good quantum efficiency at current densities of kA/cm2”
We investigate the potential for perovskite light emitting diodes to reach high brightness operation. To reach high brightness, it is required to achieve good EQE (external quantum efficiency) at high current densities. In the state of the art, perovskite LEDs have shown very good EQE (>10%) already, but usually only at low current densities of 1 to 10 mA/cm2. At current densities exceeding 100 mA/cm2, they typically exhibit EQE roll-off. In our work, we investigate the root cause of this EQE roll-off and we will show some ways to mitigate it. As a result, we achieve good EQE at current densities up to the level of kA/cm2.
Tung-Huei Ke - Technology developments in FMM-free direct R-G-B smart OLED pixels
Developments in OLED full-color fabrication processes are crucial for next-generation displays. Fine-Metal Mask (FMM) method is utilized to fabricate medium and small size OLED displays with high efficiency and high brightness for the direct RGB OLED pixels, even though the substrate size and pixel aperture ratio are limited due to the mask bending and mask clogging during OLED fabrications. Color-by-white (CBW) OLED is employed in OLED TVs and microdisplays fabrication for substrate size and pixel density, respectively. However, the light absorption in the color filter limits the maximum brightness and current efficiency in CBW OLED. High brightness and high pixel density are crucial for displays in VR/AR applications. Ultrahigh-resolution shadow masks have been realized with a pixel density of 2k ppi for OLED microdisplay . Tandem white OLED has been introduced in the CBW OLED microdisplay to achieve high brightness with high OLED driving voltage . It is essential to develop technology to achieve high brightness, high pixel density with low driving voltage simultaneously.
Paweł E. Malinowski - Thin-Film Photodetectors Enabling Infrared Vision in Future Consumer Devices
Image sensors innovations have been propelling adoption of billions of cameras in consumer devices. Silicon-based imagers are perfect for the visible range (to reproduce human vision) and are constantly improving also in the near-infrared range (especially at 940 nm used in sensors with active illumination). Imaging further in the spectrum, in the short-wave infrared (SWIR) range, promises several benefits: lower background (better contrast), augmented vision (seeing through fog/smoke/clouds), material identification (e.g. water content) and low-light visibility (e.g. night vision). The fundamental limit of the Si bandgap forces the search for alternative absorber materials. Thin-film photodetectors (TFPD) are proposed as an affordable and better scalable alternative to III-V materials such as InGaAs. Monolithic integration enables small pixel size, high resolution and industrial throughput, while providing sufficient sensitivity for many applications.
Kris Myny - Design Considerations for µLED Displays.
In the past years, micro light-emitting diodes (µLEDs) have made an impressive entrance into the display industry. Nevertheless, µLEDs introduce new challenges to the state-of-the-art (SOTA) electronics design. Different design approaches for µLED are currently pursued, one starting from light-emitting diode (LED) walls, and one starting from active matrix organic LED (AMOLED) design. In this work, we discuss these different approaches, and we propose a hybrid approach. By combining the best part of different approaches in a new pixel circuit, we can tackle these challenges.