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Study on the Reliability of an OLED Pixel Circuit Using Transient Simulation  

Jung, Taeho (Department of Electronic and IT Media Engineering, Seoul National University of Science and Technology)
Publication Information
Journal of the Semiconductor & Display Technology / v.20, no.4, 2021 , pp. 141-145 More about this Journal
Abstract
The brightness of the Organic Light Emitting Diode (OLED) display is controlled by thin-film transistors (TFTs). Regardless of the materials and the structures of TFTs, an OLED suffers from the instable threshold voltage (Vth) of a TFT during operation. When designing an OLED pixel with circuit simulation tool such as SPICE, a designer needs to take Vth shift into account to improve the reliability of the circuit and various compensation methods have been proposed. In this paper, the effect of the compensation circuits from two typical OLED pixel circuits proposed in the literature are studied by the transient simulation with a SPICE tool in which the stretched-exponential time dependent Vth shift function is implemented. The simulation results show that the compensation circuits improve the reliability at the beginning of each frame, but Vth shifts from all TFTs in a pixel need to be considered to improve long-time reliability.
Keywords
OLED; TFT; Threshold voltage shift; Reliability; SPICE;
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