An active matrix organic light emitting diode pixel circuit and its driving scheme for high frame frequency are proposed for implementation of a 3D display. The proposed pixel circuit can compensate the threshold voltage distribution of low temperature poly silicon-thin film transistors at high-speed operation of 240Hz or more. According to the simulation, current deviation of 1.73% and 3.94% are obtained at frame rates of 240Hz and 480Hz when V th distribution is ±0.5 V.

Abstract— Large‐sized active‐matrix organic light‐emitting diode (AMOLED) displays require high‐frame‐rate driving technology to achieve high‐quality 3‐D images. However, higher‐frame‐rate driving decreases the time available for compensating Vth in the pixel circuit. Therefore, a new method needs to be developed to compensate the pixel circuit in a shorter time interval. In this work, image quality of a 14‐in. quarter full‐high‐definition (qFHD) AMOLED driven at a frame rate of over 240 Hz was investigated. It was found that image degradation is related to the time available for compensation of the driving TFT threshold voltage. To solve this problem, novel AMOLED pixel circuits for high‐speed operation are proposed to compensate threshold‐voltage variation at frame rates above 240 Hz. When Vth is varied over ±1.0 V, conventional pixel circuits showed current deviations of 22.8 and 39.8% at 240 and 480 Hz, respectively, while the new pixel circuits showed deviations of only 2.6 and 5.4%.

Oxide TFTs have a negative threshold voltage (V th ), which can become even more negative in response to DC or AC stress. Therefore, these voltage stresses can cause severe leakage current in a scan driver. In this paper, a scan driver with dynamic threshold voltage control (DTVC) is proposed to minimize the leakage current and enlarge operating margin. Effectiveness of DTVC was verified with a 14-inch AMOLED. .

A driving method has been developed for a 2D-3D switchable AMOLED using progressive emission (PE) or simultaneous emission (SE). The proposed method is implemented by selecting PE mode for 2D to improve light emission ratio and SE mode for 3D to reduce left-right crosstalk without sacrificing luminance. This method also improves the contrast ratio by removing unnecessary light emission and can offer better uniformity by increasing the threshold voltage compensation time. A 240Hz-driven 30" 3D AMOLED display was built and it was confirmed that there is no ELVDD surge current in the SE mode. IntroductionRecently, various companies have focused on development of large-size AMOLED panels [1] and three dimensional (3D) displays [2,3]. Generally, there are two methods to drive an AMOLED panel. The first method is progressive emission (PE). The PE method uses sequential emission line by line after a data programming step. This method has been used to drive small-size AMOLED panels. The second method is simultaneous emission (SE). In the SE method, all pixels emit at the same time after the data programming step.The PE method has advantages such as higher light emission ratio and longer programming time compared to the SE method. This method also relieves electrical stress on an OLED by reducing OLED current, and lowers power consumption of the driving circuit. However, the conventional progressive driving scheme does not allow sufficient to compensate for threshold voltage variation of TFTs due to short programming time in high speed driven large-size AMOLED panels. It is necessary to increase the threshold voltage compensation time in order to improve uniformity of high speed driven large-size AMOLED panels.3D displays are classified into two types: stereoscopic 3D displays with special glasses to separate left and right images, and autostereoscopic 3D displays without glasses [4]. Auto-stereoscopic displays have some problems with limited viewing zone (angle and distance) and L-R crosstalk. However, stereoscopic displays that include passive/active glasses can be made L-R crosstalk-free from all viewing positions [2]. In order to realize L-R crosstalkfree performance without sacrificing luminance, the SE method is needed.In this paper, a driving method is proposed for a 2D-3D switchable AMOLED that can use both the PE method and the SE method. 2.Driving methods for 2D/3D switchable AMOLED display Figure 1 shows display driving schemes for the 2D-3D switchable AMOLED panel. Figure 1(a) shows 60Hz scanning progressive emission (PE) for 2D while figure 2(b) shows 240Hz scanning simultaneous emission (SE) for 2D. We propose the PE method for 2D because the scanning speed is 4 times slower than that of the SE method. This PE method can reduce the power consumption of the driving circuit with low frequency driving. In addition, a light emission ratio over 90% can be achieved in the PE method, which is larger than that of the SE method. This advantage can help relieve stress on the OLED by passing smaller current. We also p...

Simultaneous Emission with Active Voltage control (SEAV) is a strong candidate for crosstalk‐free driving of 3D Active Matrix Organic Light Emitting Diode (AMOLED) displays. A gate driver for a SEAV 3D AMOLED panel needs two operating modes: the simultaneous switching mode and the progressive scanning mode. However, conventional gate drivers can operate in only progressive scanning mode. In this paper, a new integrated gate driver to support both of these modes is proposed and applied to a prototype 3D AMOLED display panel.