Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme

This study investigated novel driving scheme for low-temperature polycrystalline silicon and oxide (LTPO) active-matrix organic light-emitting diode (AMOLED) displays under variable refresh rate (VRR) driving conditions with aim of reducing the brightness instability (i.e., flicker and luminance var...

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Main Authors: Li Jin Kim, Sujin Jung, Yong Seon Hwang, I. Sak Lee, Chang Hoon Jeon, Sang Yoon Park, Hyun Jae Kim
Format: Article
Language:English
Published: Taylor & Francis Group 2025-04-01
Series:Journal of Information Display
Subjects:
Online Access:https://www.tandfonline.com/doi/10.1080/15980316.2024.2424187
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author Li Jin Kim
Sujin Jung
Yong Seon Hwang
I. Sak Lee
Chang Hoon Jeon
Sang Yoon Park
Hyun Jae Kim
author_facet Li Jin Kim
Sujin Jung
Yong Seon Hwang
I. Sak Lee
Chang Hoon Jeon
Sang Yoon Park
Hyun Jae Kim
author_sort Li Jin Kim
collection DOAJ
description This study investigated novel driving scheme for low-temperature polycrystalline silicon and oxide (LTPO) active-matrix organic light-emitting diode (AMOLED) displays under variable refresh rate (VRR) driving conditions with aim of reducing the brightness instability (i.e., flicker and luminance variation) for seamless performance. The mechanisms underlying brightness fluctuations in displays were examined, focusing on frequency-dependent differences in gate-inpanel (GIP) operations. Notably, our study revealed additional factors within the GIP operation that cause LTPO flicker and VRR performance, in addition to previously identified factors of thin-film transistor hysteresis and OLED charging. Consequently, variable GIP voltage driving method that reduced these issues and enhanced display performance was proposed. The proposed method could minimize brightness fluctuations to levels imperceptible to users and facilitate performance improvement through driving options in peripheral circuits without modifying panel design and is applicable across various applications utilizing LTPO OLED technology. Its driving scheme was validated through simulation and measurement of luminance variation during frequency transition using 6.0-inch LTPO-applied AMOLED displays. The experimental results indicated a decrease in luminance difference from 14.2% to 1.5%, particularly at extremely low brightness level of 0.2 nit. The luminance distortion decreased from 7 to less than 1, which is a just noticeable color difference (JNCD).
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spelling doaj-art-5bcd0070547c43c19e22b3f725e041c72025-08-20T03:24:47ZengTaylor & Francis GroupJournal of Information Display1598-03162158-16062025-04-0126218719610.1080/15980316.2024.2424187Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation schemeLi Jin Kim0Sujin Jung1Yong Seon Hwang2I. Sak Lee3Chang Hoon Jeon4Sang Yoon Park5Hyun Jae Kim6School of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of KoreaSchool of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of KoreaSchool of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of KoreaLG Display, Co., Ltd., Paju, Republic of KoreaLG Display, Co., Ltd., Paju, Republic of KoreaLG Display, Co., Ltd., Paju, Republic of KoreaSchool of Electrical and Electronic Engineering, Yonsei University, Seoul, Republic of KoreaThis study investigated novel driving scheme for low-temperature polycrystalline silicon and oxide (LTPO) active-matrix organic light-emitting diode (AMOLED) displays under variable refresh rate (VRR) driving conditions with aim of reducing the brightness instability (i.e., flicker and luminance variation) for seamless performance. The mechanisms underlying brightness fluctuations in displays were examined, focusing on frequency-dependent differences in gate-inpanel (GIP) operations. Notably, our study revealed additional factors within the GIP operation that cause LTPO flicker and VRR performance, in addition to previously identified factors of thin-film transistor hysteresis and OLED charging. Consequently, variable GIP voltage driving method that reduced these issues and enhanced display performance was proposed. The proposed method could minimize brightness fluctuations to levels imperceptible to users and facilitate performance improvement through driving options in peripheral circuits without modifying panel design and is applicable across various applications utilizing LTPO OLED technology. Its driving scheme was validated through simulation and measurement of luminance variation during frequency transition using 6.0-inch LTPO-applied AMOLED displays. The experimental results indicated a decrease in luminance difference from 14.2% to 1.5%, particularly at extremely low brightness level of 0.2 nit. The luminance distortion decreased from 7 to less than 1, which is a just noticeable color difference (JNCD).https://www.tandfonline.com/doi/10.1080/15980316.2024.2424187Active-matrix organic light-emitting diode (AMOLED)low-temperature polycrystalline silicon and oxide (LTPO)variable refresh rate (VRR)seamless characteristic on-bias stress voltage (OBV)picture quality enhancementPSPICE simulation
spellingShingle Li Jin Kim
Sujin Jung
Yong Seon Hwang
I. Sak Lee
Chang Hoon Jeon
Sang Yoon Park
Hyun Jae Kim
Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme
Journal of Information Display
Active-matrix organic light-emitting diode (AMOLED)
low-temperature polycrystalline silicon and oxide (LTPO)
variable refresh rate (VRR)
seamless characteristic on-bias stress voltage (OBV)
picture quality enhancement
PSPICE simulation
title Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme
title_full Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme
title_fullStr Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme
title_full_unstemmed Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme
title_short Image quality enhancement in variable refresh rate LTPO-based AMOLED displays using a gate in panel voltage compensation scheme
title_sort image quality enhancement in variable refresh rate ltpo based amoled displays using a gate in panel voltage compensation scheme
topic Active-matrix organic light-emitting diode (AMOLED)
low-temperature polycrystalline silicon and oxide (LTPO)
variable refresh rate (VRR)
seamless characteristic on-bias stress voltage (OBV)
picture quality enhancement
PSPICE simulation
url https://www.tandfonline.com/doi/10.1080/15980316.2024.2424187
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