Chinese Journal of Liquid Crystals and Displays, Volume. 37, Issue 3, 358(2022)
Improvement of threshold voltage compensation of LTPS AMOLED pixel circuit
The key factors affecting threshold voltage variation compensation are identified through analyzing the operation processes of a relevant voltage program LTPS AMOLED pixel circuit. The factors include charging time restriction on threshold voltage detecting process due to data voltage signal refreshing period, and accuracy loss of threshold voltage in voltage program caused by capacity increment of related TFTs. Circuit countermeasure to these adverse factors are put forward to extend the charging time through separating the threshold voltage detection from data voltage signal refreshing process, and to compensate the error due to capacity increment through a TFT with reversed capacity increment. In pixel circuit state simulation under a low grey level display state, the variation of OLED driving current of pixel circuit of separated threshold voltage detection and data voltage signal refreshing is less than a seventh current variation of the reference circuit, and the variation of OLED driving current with capacity increment compensation is about half the current variation of the pixel circuit without capacity increment compensation. The improving effects in samples demonstration are consistent with the trend of simulation results.
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HUANG-FU Lu-jiang, ZHU Jian-chao, ZHAO Xu-liang, LU Jiang-nan, LIU Li-bin. Improvement of threshold voltage compensation of LTPS AMOLED pixel circuit[J]. Chinese Journal of Liquid Crystals and Displays, 2022, 37(3): 358
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Received: Dec. 20, 2021
Accepted: --
Published Online: Jul. 21, 2022
The Author Email: HUANG-FU Lu-jiang (lj.huangfu@boe.com.cn)