共查询到10条相似文献,搜索用时 172 毫秒
1.
An AMOLED pixel circuit for high image quality of 1000 ppi mobile displays in AR and VR applications 下载免费PDF全文
Nack‐Hyeon Keum Seong‐Kwan Hong Chong Chul Chai Oh‐Kyong Kwon 《Journal of the Society for Information Display》2018,26(2):71-78
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. 相似文献
2.
Sang‐Hoon Jung Hong‐Koo Lee Tae‐Joon Ahn Chang‐Yeon Kim Chang‐Dong Kim In‐Jae Chung 《Journal of the Society for Information Display》2007,15(8):541-544
Abstract— A new voltage‐driving active‐matrix organic light‐emitting diode (AMOLED) pixel circuit is proposed to improve the display image‐quality of AMOLED displays. Because OLEDs are current‐driven devices, the I × R voltage drop in the power lines is evitable. Accordingly, the I × R voltage‐drop compensation scheme should be included in the pixel‐driving method when a voltage‐compensation method is used. The proposed pixel was designed for the compensation of an I × R voltage drop in the power lines as well as for the compensation of the threshold‐voltage non‐uniformity of low‐temperature polycrystalline‐silicon thin‐film transistors (LTPS TFTs). In order to verify the compensation ability of the proposed pixel, SPICE simulation was performed and compared with those of other conventional pixels. When the Vss voltage varies from 0 to 1 V, the drain current of the proposed pixel decreased by under 1% while that of conventional Vth compensation methods without Vss compensation decreased by over 60%. 2.2‐in. QCIF+ full‐color AMOLED displays, which employ the proposed pixel, have been also developed. It was verified by comparison of the display image quality with a conventional panel that our proposed panel successfully overcame the voltage‐drop problems in the power lines. 相似文献
3.
Yeon Gon Mo Minkyu Kim Chul Kyu Kang Jong Han Jeong Yong Sung Park Chaun Gi Choi Hye Dong Kim Sang Soo Kim 《Journal of the Society for Information Display》2011,19(1):16-20
Abstract— Amorphous‐oxide thin‐film‐transistor (TFT) arrays have been developed as TFT backplanes for large‐sized active‐matrix organic light‐emitting‐diode (AMOLED) displays. An amorphous‐IGZO (indium gallium zinc oxide) bottom‐gate TFT with an etch‐stop layer (ESL) delivered excel lent electrical performance with a field‐effect mobility of 21 cm2/V‐sec, an on/off ratio of >108, and a subthreshold slope (SS) of 0.29 V/dec. Also, a new pixel circuit for AMOLED displays based on amorphous‐oxide semiconductor TFTs is proposed. The circuit consists of four switching TFTs and one driving TFT. The circuit simulation results showed that the new pixel circuit has better performance than conventional threshold‐voltage (VTH) compensation pixel circuits, especially in the negative state. A full‐color 19‐in. AMOLED display with the new pixel circuit was fabricated, and the pixel circuit operation was verified in a 19‐in. AMOLED display. The AMOLED display with a‐IGZO TFT array is promising for large‐sized TV because a‐IGZO TFTs can provide a large‐sized backplane with excellent uniformity and device reliability. 相似文献
4.
Bo‐Ting Chen Ya‐Hsiang Tai Ying‐Jyun Wei Chun‐Chien Tsai Chun‐Yao Huang Yu‐Ju Kuo Huang‐Chung Cheng 《Journal of the Society for Information Display》2006,14(9):793-800
Abstract— New pixel‐circuit designs for active‐matrix organic light‐emitting diodes (AMOLEDs) and a new analog buffer circuit for the integrated data‐driver circuit of active‐matrix liquid‐crystal displays (AMLCDs) and AMOLEDs, based on low‐temperature polycrystalline‐silicon thin‐film transistors (LTPS‐TFTs), were proposed and verified by SPICE simulation and measured results. Threshold‐voltage‐compensation pixel circuits consisting of LTPS‐TFTs, an additional control signal line, and a storage capacitor were used to enhance display‐image uniformity. A diode‐connected concept is used to calibrate the threshold‐voltage variation of the driving TFT in an AMOLED pixel circuit. An active load is added and a calibration operation is applied to study the influences on the analog buffer circuit. The proposed circuits are shown to be capable of minimizing the variation from the device characteristics through the simulation and measured results. 相似文献
5.
Ilias Pappas Stylianos Siskos Charalabos A. Dimitriadis 《Journal of the Society for Information Display》2010,18(10):721-731
Abstract— A new threshold‐voltage compensation technique for polycrystal line‐silicon thin‐film transistors (poly‐Si TFTs) used in active‐matrix organic light‐emitting‐diode (AMOLED) display pixel circuits is presented. The new technique was applied to a conventional 2‐transistor—1‐capacitor (2T1C) pixel circuit, and a new voltage‐programmed pixel circuit (VPPC) is proposed. Theoretically, the proposed pixel is the fastest pixel with threshold‐voltage compensation reported in the literature because of the new compression technique implemented with a static circuit block, which does not affect the response time of the conventional 2T1C pixel circuit. Furthermore, the new pixel exhibits all the other advantages of the 2T1C pixel, such as the simplicity of the peripheral drivers and improves other characteristics, such as its behavior in the temperature variations. The verification of the proposed pixel is made through simulations with HSpice. In order to obtain realistic simulations, device parameters were extracted from fabricated low‐temperature poly‐Si (LTPS) TFTs. 相似文献
6.
《Displays》2017
This paper proposes an oxide TFT DC-type shift register that consists of eleven TFTs and one bootstrapping capacitor. The proposed circuit connects drain nodes of large size pull-up TFTs of output drivers to positive supply voltage instead of alternating clock signals for low power consumption. In addition, a robust internal inverter capable of maintaining the high voltage level of the output over the large positive threshold voltage shift by bootstrapping is implemented. For a 120 Hz Full-HD display, the SPICE simulation estimates the clock power consumption of the proposed DC-type circuit as 0.56 mW at 32 shift registers and ensures the robust operation over the wide range of threshold voltage shift from −4 V to 10 V. 相似文献
7.
Juhn Suk Yoo Hojin Lee Jerzy Kanicki Chang‐Dong Kim In‐Jae Chung 《Journal of the Society for Information Display》2007,15(8):545-551
Abstract— A novel pixel circuit for electrically stable AMOLEDs with an a‐Si:H TFT backplane and top‐anode organic light‐emitting diode is reported. The proposed pixel circuit is composed of five a‐Si:H TFTs, and it does not require any complicated drive ICs. The OLED current compensation for drive TFT threshold voltage variation has been verified using SPICE simulations. 相似文献
8.
Abstract— A new driving scheme for active‐matrix organic light‐emitting diodes (AMOLED) displays based on voltage programming is proposed. While conventional voltage drivers have a trade‐off between speed and accuracy, the new scheme is inherently fast and accurate. Based on the new driving scheme, a fast pixel circuit is designed using amorphous‐silicon (a‐Si) thin‐film transistors (TFTs). As the simulation results indicate, this pixel circuit can compensate the threshold‐voltage shift (VT shift) of the driver transistors. This pixel can be programmed in just 10 μsec, and it can compensate the threshold‐voltage shifts over 5 V with an error rate of less than 5% for a 1 ‐μA pixel current. 相似文献
9.
Jungwoo Lee Jongsu Oh Eun Kyo Jung KeeChan Park Jae‐Hong Jeon Soo‐Yeon Lee Yong‐Sang Kim 《Journal of the Society for Information Display》2021,29(1):68-77
In this paper, a high‐reliability gate driver circuit is proposed to prevent multiple outputs. The proposed circuit ensures reliability of the pull‐up thin‐film transistor (TFT) by periodically discharging the Q node voltage to the low‐level voltage (VGL) in the off stage. In addition, the output node is composed of two pull‐down TFTs that are driven alternately to ensure stability against bias stress. Thus, because the reliabilities of the pull‐up and pull‐down TFTs can be guaranteed simultaneously, the stability of the entire circuit is improved. Based on the simulation results, the rising and falling times of the output pulse are stable within 1.77 and 1.28 μs, respectively, even when the threshold voltage of the entire TFT is shifted by +10.0 V. In addition, the ripple voltage of the proposed circuit is almost eliminated and is within 0.79% of the total swing voltage. Moreover, through current is prevented in the proposed circuit because the turn‐on durations of the pull‐up and pull‐down units are completely nonoverlapping, which suggests that unnecessary power consumption can be eliminated. Therefore, based on 2,160 stages, the total power consumption of the proposed circuit is reduced by 34.7 mW from 276.3 to 241.6 mW. 相似文献
10.
Hong‐Sik Park Kyong‐Hwan Oh Hai‐Jung In Oh‐Kyong Kwon 《Journal of the Society for Information Display》2012,20(3):162-168
Abstract— A pixel structure for shutter‐glasses‐type stereoscopic 3‐D active‐matrix organic light‐emitting‐diode (AMOLED) displays is proposed. The proposed pixel programs data to the pixel during the light‐emission time of an OLED. Because the emission time of the proposed pixel is extended, it is expected that the proposed pixel not only decreases the peak current of the OLED during the emission period but also reduces flicker. Moreover, the aperture ratio of the proposed pixel is 58.69% for a 50‐in. full‐high‐definition (FHD) condition by minimizing the number of thin‐film transistors (TFTs), capacitors, and control signal lines as seven TFTs, two capacitors, two power lines, and four control lines per unit pixel. Simulation results show that the error in the emission current of the proposed pixel is from ?0.82% to +0.90% when the threshold‐voltage variation of the driving TFT is ±1.00 V, and the maximum variation of the emission current is ?1.35% when a voltage drop in the power line is ?0.50 V on a full‐white‐image display. 相似文献