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.

IDW '23, Niigata, Japan

December 6 - December 8, 2023 (Wen. - Fri.), TOKI MESSE Niigata Convention Center

Adaptive Frequency Driving Scan Driver for Low Power Display based on a-InGaZnO TFTs

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

Abstract

 In this paper, a scan driver combined with logic circuit using amorphous indium-gallium-zinc-oxide (a-InGaZnO) thin-film transistors (TFTs) is proposed. Logic circuit masks the output signal from the scan driver in order to control the driving frequency. Proposed frequency adaptive scan driver is expected to reduce power consumption depending on the display contents.

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.

ICEIC 2025, Osaka, Japan

January 19 - January 22, 2025 (Sun. - Wen.), Osaka International House

Design of Low Power Scan Driver Based on a-InGaZnO TFTs for Frame Masking Technique with Extra Clock Signal Modulation

Chaeyeon Park, Dongseok Kim, Hyunwoo Kim, and Hojin Lee

Abstract

We proposed a novel low-power scan driver using frame masking techniques, which selectively disables scan driver outputs based on the type of content, thereby reducing unnecessary pixel updates. The proposed frame masking drive effectively reduces power consumption not only for the scan driver but also for the display panel itself.