In this paper, an active‐matrix organic light‐emitting diode pixel circuit is proposed to improve the image quality of 5.87‐in. mobile displays with 1000 ppi resolution in augmented and virtual reality applications. The proposed pixel circuit consisting of three thin‐film transistors (TFTs) and two capacitors (3T2C) employs a simultaneous emission driving method to reduce the number of TFTs and the emission current error caused by variations in threshold voltage (Vth) and subthreshold slope (SS) of the low‐temperature polycrystalline silicon TFTs. Using the simultaneous emission driving method, the compensation time is increased to 90 μs from 6.5 μs achieved in the conventional six TFTs and one capacitor (6T1C) pixel circuit. Consequently, the emission current error of the proposed 3T2C pixel circuit was reduced to ±3 least significant bit (LSB) from ±12 LSB at the 32nd gray level when the variations in both the Vth and SS are ±4σ. Moreover, both the crosstalk errors due to the parasitic capacitances between the adjacent pixel circuits and due to the leakage current were achieved to be less than ±1 LSB over the entire gray level. Therefore, the proposed pixel circuit is very suitable for active‐matrix organic light‐emitting diode displays requiring high image quality.

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In this paper, an active-matrix organic light emitting diode (AMOLED) pixel circuit is proposed for 1000 ppi and 5.87-inch mobile displays with augmented and virtual reality applications. The proposed pixel circuit consisting of 3 thin-film transistors (TFTs) and 2 capacitors employs a simultaneous emission driving method to reduce the number of TFTs. The simulation results of the proposed pixel circuit showed that the emission current errors caused by the threshold voltage variation of driving TFT and crosstalk error were less than ±0.4 LSB and ±1LSB, respectively, over the entire gray level. Therefore, the proposed pixel circuit is highly suitable for AMOLED displays.

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In this paper, we propose a compensation method for variations in the subthreshold slope (SS) and threshold voltage (Vth) of the low-temperature polycrystalline silicon thin-film transistors (LTPS TFTs) in an attempt to improve the image quality of the active matrix organic light-emitting diode (AMOLED) displays for mobile applications. The proposed compensation method provides a uniform voltage to the OLED according to the gray level without being affected by variations in the SS and Vth of the LTPS TFTs. To verify the performance of the proposed compensation method, a test pattern, including two pixel circuits designed for 5.7-inch quadruple high-definition AMOLED display was fabricated and measured. The measurement results showed that the proposed compensation method achieved an emission current error of the pixel circuit of only ±3.1 LSB at the 255 th gray level. Therefore, the proposed compensation method is very suitable for AMOLED displays requiring high image quality.INDEX TERMS Thin film transistors, organic light-emitting diode displays, pixel circuit, high image quality.