TY - JOUR
T1 - Compensation pixel circuit to improve image quality for mobile AMOLED displays
AU - Lin, Chih Lung
AU - Lai, Po Chun
AU - Shih, Li Wei
AU - Hung, Chia Che
AU - Lai, Po Cheng
AU - Lin, Tsu Yuan
AU - Liu, Kuang Hsiang
AU - Wang, Tsang Hong
N1 - Funding Information:
Manuscript received February 24, 2018; revised June 5, 2018 and August 24, 2018; accepted November 4, 2018. Date of publication November 28, 2018; date of current version January 25, 2019. This work was supported in part by the Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan, in part by the Ministry of Science and Technology of Taiwan under Project MOST 107-2221-E-006-188-MY3 and Project MOST 106-2622-E-006-011-CC2, and in part by AU Optronics Corporation. This paper was approved by Associate Editor David Stoppa. (Corresponding author: Chih-Lung Lin.) C.-L. Lin is with the Department of Electrical Engineering, National Cheng Kung University, Tainan 701-01, Taiwan, and also with the and the Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan 701-01, Taiwan (e-mail: [email protected]).
Publisher Copyright:
© 2018 IEEE.
PY - 2019/2
Y1 - 2019/2
N2 - This paper proposes a new pixel circuit using lowerature polycrystalline silicon thin-film transistors (LTPS TFTs) for use in mobile active matrix organic light-emitting diode (AMOLED) displays. The purpose of a pixel circuit is to supply stable and uniform currents to current-driving devices of OLEDs. The proposed pixel circuit uses overlapping compensation times to extend the period of precise sensing of VTH variations of LTPS TFTs. Moreover, the proposed circuit prevents a current from flowing into an OLED when the OLED is not operated in the emission stage to avoid image flicker. An 1.3-in panel that uses the proposed pixel circuit is fabricated. Measurement results verify that the increased TCOMP of 33.3 μs results in higher contrast ratio and lower required data voltages than those at TCOMP values of 4.3 and 2.2 μs. Red, green, and blue images displayed by the fabricated panel with a TCOMP of 33.3 μs with a 255 gray level are all much more uniform than with TCOMPS of 4.3 and 2.2 μs. White images with a TCOMP of 33.3 μs for 16 and 8 gray levels on the fabricated panel confirm that the serious line and spot defects in the images with TCOMP values of 4.3 and 2.2 μs are effectively eliminated. Therefore, the proposed pixel circuit is suitable for use in mobile AMOLED displays.
AB - This paper proposes a new pixel circuit using lowerature polycrystalline silicon thin-film transistors (LTPS TFTs) for use in mobile active matrix organic light-emitting diode (AMOLED) displays. The purpose of a pixel circuit is to supply stable and uniform currents to current-driving devices of OLEDs. The proposed pixel circuit uses overlapping compensation times to extend the period of precise sensing of VTH variations of LTPS TFTs. Moreover, the proposed circuit prevents a current from flowing into an OLED when the OLED is not operated in the emission stage to avoid image flicker. An 1.3-in panel that uses the proposed pixel circuit is fabricated. Measurement results verify that the increased TCOMP of 33.3 μs results in higher contrast ratio and lower required data voltages than those at TCOMP values of 4.3 and 2.2 μs. Red, green, and blue images displayed by the fabricated panel with a TCOMP of 33.3 μs with a 255 gray level are all much more uniform than with TCOMPS of 4.3 and 2.2 μs. White images with a TCOMP of 33.3 μs for 16 and 8 gray levels on the fabricated panel confirm that the serious line and spot defects in the images with TCOMP values of 4.3 and 2.2 μs are effectively eliminated. Therefore, the proposed pixel circuit is suitable for use in mobile AMOLED displays.
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U2 - 10.1109/JSSC.2018.2881922
DO - 10.1109/JSSC.2018.2881922
M3 - Article
AN - SCOPUS:85057848162
SN - 0018-9200
VL - 54
SP - 489
EP - 500
JO - IEEE Journal of Solid-State Circuits
JF - IEEE Journal of Solid-State Circuits
IS - 2
M1 - 8551265
ER -