IMID 2023, Pusan, Korea

August 22 - August 25, 2023 (Tue. - Fri.), Bexco

Novel AM-OLED Pixel Circuit Compensating for Threshold Voltage Variations and Depletion Mode of a-IGZO TFT 

Hyunwoo Kim , Yongchan Kim , Jinho Moon , and Hojin Lee

Abstract

 This paper proposes a novel voltage-programmed pixel circuit based on a-IGZO TFT for AM-OLED that compensates for V_TH shifts of driving TFT. The proposed pixel circuit is expected to achieve stable and wide OLED current even if the threshold voltage of the driving TFT is shifted.

IMID 2024, Jeju, Korea

August 20 - August 23, 2024 (Tue. - Fri.), ICC Jeju

Terahertz Chiral Metasurface Based on Kirigami Structure for Controlling Circular Dichroism

Kyungbin Cho, Wonwoo Lee, and Hojin Lee

Abstract

 The utilization of terahertz (THz) frequency range in spectroscopy provides immense promise for various applications such as enantiomer identification, biomolecular analysis, medical diagnostics, pharmaceutical assessment, and security screening due to its unique characteristics, including linear wave propagation, object penetration, and low photon energy. Notably, terahertz circular dichroism (TCD) spectroscopy emerges as a potent tool for analyzing material properties and discerning enantiomers in biomolecules like nucleic acids and proteins. However, the inherent low response of biomolecules to circular dichroism (CD) in the THz range presents a formidable obstacle in biomolecular analysis. To address this challenge, chiral metamaterials offer a solution by enabling precise control over electromagnetic wave characteristics such as transmission, phase, and polarization in the THz range, thereby enhancing the amplification of chirality properties in materials. In this study, we propose a novel approach to manipulate TCD utilizing a chiral metasurface based on a kirigami structure.

IMID 2023, Pusan, Korea

August 22 - August 25, 2023 (Tue. - Fri.), Bexco

Ultra-High Resolution Organic Light-Emitting Diodes Combined with Plasmonic Nanomesh Electrodes

Ryungyu Lee, Keun-Yeong Choi, and Hojin Lee

Abstract

 Organic light-emitting diodes (OLEDs) have led to the rapid growth of the next-generation display technology due to high luminance efficiency, vivid color, and high contrast ratio, thereby expanding their applications from conventional mobile or TV displays to hyper-realistic microdisplay such as virtual reality (VR)/ augmented reality (AR) displays. Particularly, research have done combined plasmonic nanotechnology and organic light-emitting devices are being actively studied to improve optical and electrical properties. In this work, we propose a high resolution OLEDs based on a double resonance structure combined with an asymmetric Fabry-Perot (FP) etalon structure and a plasmonic nanomesh electrodes (PNE) using a photo- patternable organic light-emitting semiconductor without deterioration of intrinsic physical/photoelectric properties of OLEDs.

2017 iMiD, Busan, Korea

August 28 - 31, 2017 (Mon - Thur), Convention Hall, BEXCO

<Poster Session>

Solution-Processed a-InGaZnO Thin Film Transistor Based Operational Amplifier for the Flexible Display Driving System

Yongchan Kim, Daejung Kim, Keun-Yeong Choi, Dayoon Lee, and Hojin Lee

 Abstract

 Currently, amorphous indium-gallium-zinc-oxide (a-InGaZnO) thin-film transistors (TFTs) have attracted much interest as a next-generation TFT backplane thanks to their high field-effect mobility, low leakage current, and good electrical stability. In particular, the formation of the active layer in a-InGaZnO TFTs through the solution process has been actively researched recently because of their optical transparency, flexibility and superior air stability. In this paper, we adopted a DLP (direct light patterning) process [1], and demonstrated the electrical characteristics of the TFTs and logic circuits fabricated on the glass. Through this study, we expect to realize solution-processed system-on-glass (SOG), for transparent, portable, and flexible flat panel displays.

IMID 2022, Pusan, Korea

August 23 - August 26, 2022 (Tue. - Fri.), Bexco