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A 31-inch 4K flexible active-matrix organic light-emitting diode (AMOLED) display integrating with gate driver on the array (GOA) technology has been proposed and fabricated on a polyimide substrate. The GOA circuits, composed of two series-connected thin-film transistors (TFTs) and dual low-voltage power structure, are introduced to decrease the leakage current in TFTs. They are arranged symmetrically along the sides of the display. Inkjet printing (IJP) OLED process is used to reduce the number of sub-pixels from four (R/G/B/W) in commercial white OLED process to three (R/G/B) and a high pixel density in the display (144 pixels per inch) is achieved. Moreover, top-gated (TG) amorphous indium-gallium-zinc oxide (IGZO) TFTs with good electrical and mechanical reliability, have been successfully utilized to decrease the capacitance load in the display and improve signal transfer speed in GOA. Finally, this 31-inch flexible AMOLED display was operated for 500h under accelerating test conditions of 60°C and 90% humidity. [ABSTRACT FROM AUTHOR]

A new pixel circuit is proposed for the realization of high resolution and high uniformity organic light-emitting diode on silicon (OLEDoS) microdisplays in this article. A compensation scheme is adopted to mitigate the influence of threshold voltage variation of the driving transistor on display uniformity. Furthermore, two coupling capacitors are used to reduce the voltage at the gate terminal of the driving transistor in order to extend the data voltage range. The performance of the proposed pixel circuit is verified in an industrial 0.18- $\mu \text{m}$ CMOS process. Simulation results show that the data voltage of the proposed pixel circuit ranges from 0.5 to 3.12 V, which is up to $4.37\times $ wider than the previously published pixel circuits. The emission current error of the proposed pixel circuit varies from −2.1% to 2.08%, under the condition of ±5 mV threshold voltage variation for the driving transistor. The maximum emission current error changes from −10.36% to −2.62% when the OLED turn-on voltage is increased by 5 to 20 mV due to device aging. Furthermore, the proposed pixel circuit only occupies a layout area of $8.1\,\,\mu \text{m}\,\,\times {4}\,\,\mu \text{m}$. [ABSTRACT FROM AUTHOR]

A new OLEDoS pixel circuit is proposed for high resolution micro‐displays with improved image quality. The data voltage range is extended by using two coupling capacitors to raise the voltage at the source electrode of the driving transistor. Furthermore, the image quality is improved by a compensation scheme of the threshold voltage variation of the driving transistor. The simulations on the basis of CSMC 0.25 µm CMOS model are used to verify the performance of the proposed pixel circuit. It is shown that the data voltage of the proposed pixel circuit ranges from 1.5 V to 3.05 V, which is 2.5 times of that of the conventional 2T1C pixel circuit. The emission current error is decreased to −2.6% ~ 2.6% with ±5 mV threshold voltage variation of the driving transistor for the proposed circuit. [ABSTRACT FROM AUTHOR]

An a‐IGZO TFTs integrated gate driver with programmable output waveform for AMOLED display is proposed by shared input shift registers and output stages of multiple clock‐follower structure. The driver provides not only multiple scan and control signals for internal compensation, but also extended scan pulses for external compensation. [ABSTRACT FROM AUTHOR]

A depletion‐mode amorphous indium‐gallium‐zinc‐oxide thin‐film‐transistor (a‐IGZO TFT) gate driver on array (GOA) integrated circuit has been proposed and fabricated for a 15‐inch active‐matrix organic light emitting diode (AMOLED) display in this work. The depletion‐mode a‐IGZO TFTs were turned off completely due to series‐connected two‐transistor structure and dual low‐voltage‐level power signal. For this reason, the window of Vth shift margin was wide with margin value from −5V to +10V by Spice simulation. Additionally, the proposed GOA circuit exhibited stable high‐voltage output pulse. Subsequently, GOA circuit was placed in a 15‐inch AMOLED display and the performance of the proposed circuit was confirmed. [ABSTRACT FROM AUTHOR]

A dual-gate (DG) amorphous indium–gallium–zinc-oxide thin-film transistor (TFT)-driven pixel circuit for active-matrix organic light-emitting diode displays is presented. One gate of the DGs serves as a primary gate (PG) and the other as an auxiliary gate (AG). The threshold voltage ( V\mathrm {{TH}} ) of the DG TFT under the PG operation is modulated by the AG bias voltage. The V\mathrm {{TH}} variation ( \Delta V\mathrm {{TH}} ) is compensated with the AG and the drain diode-connected structure. The validity of the presented pixel circuit is experimentally verified. The measured current error rates are less than 3.2% at a \Delta V\mathrm {{TH}} of \text TFT = \pm 0.5 V and a \Delta V\mathrm {{TH}} of OLED = 0.5 V with the emission current ranging from 7 nA to 1.13~\mu \textA . [ABSTRACT FROM AUTHOR]

This work presents a peripheral compensation scheme for AMOLED displays, in which threshold voltage and aging information of driving TFT, and the signal data voltage are analogously added in the pixel circuits without changing the gamma corrections and increasing the bit and voltage range of DAC. Without increasing the resolution and voltage range of DAC, the cost and power consumption are reduced. A driving scheme using current sensing method with adjustable settling time and peripheral compensation system are also proposed. [ABSTRACT FROM AUTHOR]

A current comparison scheme for external compensation circuit of AMOLED displays is proposed. In this scheme, a current comparator is designed to sense the difference between the reference current and the driving current of pixels and to output a corresponding digital signal to the compensation block. For the current comparator, a sense amplifier is used to amplify the current difference, which can effectively increase the accuracy of the current comparator. Simulation results show that the accuracy of the proposed current comparator is 1nA and the sensing error is lower than 0.224 %, when the reference current is 500 nA. [ABSTRACT FROM AUTHOR]