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Xu W, Yi Z, Jiang M, Wang J, Long Z, Liu L, Chi F, Wang L, Wan Q. High-Performance Multi-Level Grayscale Conversion by Driving Waveform Optimization in Electrowetting Displays. MICROMACHINES 2024; 15:137. [PMID: 38258256 PMCID: PMC10819487 DOI: 10.3390/mi15010137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/20/2023] [Accepted: 01/09/2024] [Indexed: 01/24/2024]
Abstract
As a new type of reflective display, electrowetting display (EWD) has excellent dynamic display performance, which is based on polymer coatings. However, there are still some issues which can limit its performance, such as oil backflow and the hysteresis effect which reduces the stability and response speed of EWDs. Therefore, an effective driving waveform was proposed to overcome these drawbacks, which consisted of grayscale conversions between low gray levels and high gray levels. In the driving waveform, to stabilize the EWD at any initial grayscale (low gray levels/high gray levels), an exponential function waveform and an AC signal were used. Then, the grayscale conversion was performed by using an AC signal with a switching voltage to quickly achieve the target grayscale. Finally, another AC signal was used to stabilize the EWD at the target grayscale. A set of driving waveforms in grayscale ranging across four levels was designed using this method. According to the experimental results, oil backflow and the hysteresis effect could be effectively attenuated by the proposed driving waveforms. During conversion, the response speed of EWDs was boosted by at least 9.37% compared to traditional driving waveforms.
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Affiliation(s)
- Wanzhen Xu
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Zichuan Yi
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
| | - Mouhua Jiang
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China
| | - Jiashuai Wang
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
| | - Zhengxing Long
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
- School of Information and Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China
| | - Liming Liu
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
| | - Feng Chi
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.X.); (M.J.); (J.W.); (Z.L.); (L.L.); (F.C.)
| | - Li Wang
- School of Information Engineering, Zhongshan Polytechnic, Zhongshan 528400, China; (L.W.); (Q.W.)
| | - Qiming Wan
- School of Information Engineering, Zhongshan Polytechnic, Zhongshan 528400, China; (L.W.); (Q.W.)
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Shen S, Feng H, Deng Y, Xie S, Yi Z, Jin M, Zhou G, Mulvaney P, Shui L. A reflective display based on the electro-microfluidic assembly of particles within suppressed water-in-oil droplet array. LIGHT, SCIENCE & APPLICATIONS 2023; 12:290. [PMID: 38052798 DOI: 10.1038/s41377-023-01333-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/31/2023] [Accepted: 11/08/2023] [Indexed: 12/07/2023]
Abstract
Reflective displays have stimulated considerable interest because of their friendly readability and low energy consumption. Herein, we develop a reflective display technique via an electro-microfluidic assembly of particles (eMAP) strategy whereby colored particles assemble into annular and planar structures inside a dyed water droplet to create "open" and "closed" states of a display pixel. Water-in-oil droplets are compressed within microwells to form a pixel array. The particles dispersed in droplets are driven by deformation-strengthened dielectrophoretic force to achieve fast and reversible motion and assemble into multiple structures. This eMAP based device can display designed information in three primary colors with ≥170° viewing angle, ~0.14 s switching time, and bistability with an optimized material system. This proposed technique demonstrates the basis of a high-performance and energy-saving reflective display, and the display speed and color quality could be further improved by structure and material optimization; exhibiting a potential reflective display technology.
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Affiliation(s)
- Shitao Shen
- Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, 510006, Guangzhou, China
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China
| | - Haoqiang Feng
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China
| | - Yueming Deng
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China
| | - Shuting Xie
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China
| | - Zichuan Yi
- School of Electronic Information, University of Electronic Science and Technology of China, Zhongshan Institute, 528402, Zhongshan, China
| | - Mingliang Jin
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China
| | - Guofu Zhou
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China.
| | - Paul Mulvaney
- ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Lingling Shui
- Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information and Optoelectronic Science and Engineering, South China Normal University, 510006, Guangzhou, China.
- International Joint Laboratory of Optofluidic Technology and System (LOTS), National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, 510006, Guangzhou, People's Republic of China.
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Inhibiting Oil Splitting and Backflow in Electrowetting Displays by Designing a Power Function Driving Waveform. ELECTRONICS 2022. [DOI: 10.3390/electronics11132081] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Electrowetting display (EWD) is one of the latest and most promising reflective displays. However, some defects are easily caused in a driving process. For example, the aperture ratio of pixels can be reduced due to oil splitting, and the grayscale cannot be stabilized due to charge trapping. These defects can be effectively solved by designing driving waveforms for EWDs. So, a power function driving waveform was proposed in this paper, which consisted of an oil splitting suppression stage, a direct current (DC) driving stage and an oil stabilization stage. Firstly, the relationships among luminance values, power constants and driving time were measured. An optimal oil splitting suppression stage was obtained, which could effectively inhibit oil splitting. Then, the response time could be reduced by a DC voltage in the DC driving stage. Finally, a voltage slope was tested during the oil stabilization stage, which was used to counteract voltage created by the charge trapping. The experimental results showed that compared with a linear function waveform, the response time could be shortened by 16.1%, and the luminance value could be increased by 3.8%. The aperture ratio and oil stability of EWD can be effectively improved by these findings, thereby increasing its potential application in the display field.
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Toward Suppressing Oil Backflow Based on a Combined Driving Waveform for Electrowetting Displays. MICROMACHINES 2022; 13:mi13060948. [PMID: 35744562 PMCID: PMC9228827 DOI: 10.3390/mi13060948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/06/2022] [Accepted: 06/12/2022] [Indexed: 02/01/2023]
Abstract
Electrowetting display (EWD) is a new type of paper-like reflective display based on colored oil, which has gradually become one of the most potential electronic papers with low power consumption, fast response, and full color. However, oil backflow can occur in EWDs, which makes it difficult to maintain a stable aperture ratio. In order to improve the stability of the aperture ratio of EWDs, a new driving waveform was proposed based on analyzing the phenomenon of oil backflow. The driving waveform was composed of a shrinking stage and a driving stage. Firstly, a threshold voltage of oil splitting was calculated by analyzing the luminance curve of EWDs, which were driven by different direct current (DC) voltages. Then, an exponential function waveform, which increased from the threshold voltage, was applied to suppress oil splitting. Finally, a periodic signal combined with a reset signal with a DC signal was applied during the driving stage to maintain a stable aperture ratio display. Experimental results showed that the charge trapping effect could be effectively prevented by the proposed driving waveform. Compared with an exponential function waveform, the average luminance value was increased by 28.29%, and the grayscale stability was increased by 13.76%. Compared to a linear function waveform, the aperture ratio was increased by 10.44% and the response time was reduced by 20.27%.
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Liu L, Zeng W, Long Z, Yi Z, Bai P, Tang B, Yuan D, Zhou G. Red Display for Three-Color Electrophoretic Displays with High Saturation via a Separation Stage between Black and Red Particles. MATERIALS (BASEL, SWITZERLAND) 2022; 15:2555. [PMID: 35407886 PMCID: PMC9000271 DOI: 10.3390/ma15072555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/29/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022]
Abstract
A three-color electrophoretic display (EPD) can solve the defect of an insufficient color display of black/white EPDs, but it is difficult to achieve a high red saturation due to the same driving polarity between black and red electrophoretic particles. In this work, a separation stage was proposed in the driving process to increase the red saturation in three-color EPDs. Firstly, red particles' motion was analyzed by the electrophoretic theory and Stokes' theorem to optimize driving parameters. Secondly, the activity of black particles was analyzed by testing different driving process parameters, and an optimal activation parameter for red particles was obtained. Next, the separation stage parameters were analyzed to reduce the mixing degree of black and red electrophoretic particles. Experimental results showed that the red and black electrophoretic particles could be effectively separated. Compared with an existing driving method, the red saturation was increased by 23.4%.
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Affiliation(s)
- Linwei Liu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
| | - Wenjun Zeng
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
| | - Zhengxing Long
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zongshan 528402, China
| | - Zichuan Yi
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zongshan 528402, China
| | - Pengfei Bai
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
| | - Biao Tang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
| | - Dong Yuan
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (W.Z.); (Z.L.); (P.B.); (B.T.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China
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Red Ghost Image Elimination Method Based on Driving Waveform Design in Three-Color Electrophoretic Displays. MICROMACHINES 2022; 13:mi13020275. [PMID: 35208398 PMCID: PMC8875704 DOI: 10.3390/mi13020275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/03/2022] [Accepted: 02/04/2022] [Indexed: 12/10/2022]
Abstract
Three-color electrophoretic displays (EPDs) are a new type of optoelectronic display device. However, they have the defect of red ghost images during gray scale transformation, which affects the accuracy of the gray scale display. In this paper, we proposed a new driving method for eliminating the red ghost images. A driving waveform was composed of an erasing stage, an activation stage, and a driving stage. First, the erasing stage was subdivided into a red erasing stage and an original erasing stage, the red erasing stage was used to eliminate residual red particles in the top of the microcapsules. Then, a high-frequency square wave was used as the activation stage for increasing the activity of the black and white particles. Meanwhile, the intensity of flickers could be decreased by the high-frequency square wave. Finally, the performance of the driving waveform was tested by a colorimeter. The experimental results showed that the driving waveform could effectively eliminate red ghost images by 80.43% and reduce the flicker intensity by 79.63%, compared with an existing driving waveform.
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Zhang H, Yi Z, Liu L, Chi F, Hu Y, Huang S, Miao Y, Wang L. A Fast-Response Driving Waveform Design Based on High-Frequency Voltage for Three-Color Electrophoretic Displays. MICROMACHINES 2021; 13:59. [PMID: 35056224 PMCID: PMC8777687 DOI: 10.3390/mi13010059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 12/26/2021] [Accepted: 12/26/2021] [Indexed: 11/16/2022]
Abstract
Three-color electrophoretic displays (EPDs) have the characteristics of colorful display, reflection display, low power consumption, and flexible display. However, due to the addition of red particles, response time of three-color EPDs is increased. In this paper, we proposed a new driving waveform based on high-frequency voltage optimization and electrophoresis theory, which was used to shorten the response time. The proposed driving waveform was composed of an activation stage, a new red driving stage, and a black or white driving stage. The response time of particles was effectively reduced by removing an erasing stage. In the design process, the velocity of particles in non-polar solvents was analyzed by Newton's second law and Stokes law. Next, an optimal duration and an optimal frequency of the activation stage were obtained to reduce ghost images and improve particle activity. Then, an optimal voltage which can effectively drive red particles was tested to reduce the response time of red particles. Experimental results showed that compared with a traditional driving waveform, the proposed driving waveform had a better performance. Response times of black particles, white particles and red particles were shortened by 40%, 47.8% and 44.9%, respectively.
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Affiliation(s)
- Hu Zhang
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
- School of Electronic Science and Engineering (National Exemplary School of Microelectronics), University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Zichuan Yi
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
| | - Liming Liu
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
| | - Feng Chi
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
| | - Yunfeng Hu
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
| | - Sida Huang
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
| | - Yu Miao
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (H.Z.); (L.L.); (F.C.); (Y.H.); (S.H.); (Y.M.)
| | - Li Wang
- School of Information Engineering, Zhongshan Polytechnic, Zhongshan 528400, China;
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Zhang H, Yi Z, Ma S, Deng S, Zhou W, Zeng W, Liu L, Chi F, Hu Y, Zhang C, Wang L, Zhang J. Design of Driving Waveform for Shortening Response Time of Black Particles and White Particles in Three-Color Electrophoretic Displays. MICROMACHINES 2021; 12:1306. [PMID: 34832718 PMCID: PMC8622660 DOI: 10.3390/mi12111306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/14/2021] [Accepted: 10/22/2021] [Indexed: 01/28/2023]
Abstract
The shortage of color in traditional electrophoretic displays (EPDs) can be compensated by three-color EPDs. However, the response time of black particles and white particles is increased. A new driving waveform based on the principle of three-color EPDs and electrophoresis theory was proposed to shorten the response time of black particles and white particles. The proposed driving waveform consisted of an erasing stage, an activation stage, a red driving stage, and a white or a black driving stage. The activation stage was mainly optimized in this paper. Firstly, the motion characteristics of the particles were analyzed using Stokes law and electrophoresis theory. Secondly, an optimal high frequency oscillation voltage was tested in order to improve the activity of the particles. Then, the influence of oscillation period and oscillation times on the activation stage were analyzed for optimizing the reference grayscale. According to the luminance of pixels, an oscillation period of 30 ms and an oscillation time of 30 were determined. The experimental results showed that the response time of black particles was shortened by 45%, and the response time of white particles was shortened by 40% compared with a traditional driving waveform.
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Affiliation(s)
- Hu Zhang
- School of Electronic Science and Engineering (National Exemplary School of Microelectronics), University of Electronic Science and Technology of China, Chengdu 611731, China;
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Zichuan Yi
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Simin Ma
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Shaoning Deng
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Weibiao Zhou
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Wenjun Zeng
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Liming Liu
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Feng Chi
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Yunfeng Hu
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Chongfu Zhang
- College of Eletron and Information，University of Electronic Science and Technology of China，Zhongshan Institute，Zhongshan 528402，China; (S.M.); (S.D.); (W.Z.); (W.Z.); (L.L.); (F.C.); (Y.H.); (C.Z.)
| | - Li Wang
- School of Information Engineering, Zhongshan Polytechnic, Zhongshan 528400, China;
| | - Jitao Zhang
- School of Mechanical and Electrical Engineering, Zhongshan Polytechnic, Zhongshan 528400, China;
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Zeng W, Yi Z, Zhou X, Zhao Y, Feng H, Yang J, Liu L, Chi F, Zhang C, Zhou G. Design of Driving Waveform for Shortening Red Particles Response Time in Three-Color Electrophoretic Displays. MICROMACHINES 2021; 12:578. [PMID: 34069735 PMCID: PMC8161037 DOI: 10.3390/mi12050578] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 01/18/2023]
Abstract
Three-color electrophoretic displays (EPDs) have the advantages of multi-color display and low power consumption. However, their red particles have the disadvantage of long response time. In this paper, a driving waveform, which is based on electrophoresis theory and reference gray scale optimization, was proposed to shorten the response time of red particles in three-color EPDs. The driving waveform was composed of erasing stage, reference gray scale forming stage, red driving stage, and white or black driving stage. Firstly, the characteristics of particle motion were analyzed by electrophoresis theory and Stokes law. Secondly, the reference gray scale of the driving waveform was optimized to shorten the distance between red particles and a common electrode plate. Finally, an experimental platform was developed to test the performance of the driving waveform. Experimental results showed that the proposed driving waveform can shorten the response time of red particles by 65.57% and reduce the number of flickers by 66.67% compared with the traditional driving waveform.
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Affiliation(s)
- Wenjun Zeng
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China;
| | - Zichuan Yi
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Xichen Zhou
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Yiming Zhao
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Haoqiang Feng
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China;
| | - Jianjun Yang
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Liming Liu
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Feng Chi
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Chongfu Zhang
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China; (W.Z.); (X.Z.); (Y.Z.); (H.F.); (J.Y.); (L.L.); (F.C.); (C.Z.)
| | - Guofu Zhou
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China;
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10
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Liu L, Bai P, Yi Z, Zhou G. A Separated Reset Waveform Design for Suppressing Oil Backflow in Active Matrix Electrowetting Displays. MICROMACHINES 2021; 12:mi12050491. [PMID: 33925329 PMCID: PMC8146728 DOI: 10.3390/mi12050491] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 01/18/2023]
Abstract
The electrowetting display (EWD) is a kind of reflective paper-like display. Flicker and grayscale distortion are caused by oil backflow, which is one of the important factors restricting the wide application of EWDs. The charge embedding caused by the electric field force in the dielectric layer is the cause of oil backflow. To suppress oil backflow, a separated reset waveform based on the study of oil movement is proposed in this paper. The driving waveform is divided into two parts: a reset waveform and a grayscale waveform. The reset waveform generated by a reset circuit can be used to output various voltages. The grayscale waveform is set as a traditional PWM waveform. The reset waveform is composed of a charge-releasing stage and oil-moving back stage. Two phases are contained in the charge releasing stage. The overdriving voltage is used during the first phase to reverse the voltage of all pixels. The trapped charges can then be released from the dielectric layer during the second phase. A higher voltage is used during the oil-moving back stage to drive the oil faster in the pixel. By comparing the experimental data, the oil backflow time is extended 761 times by the reset waveform. The four grayscales can be maintained by the reset waveform after driving for 300 s.
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Affiliation(s)
- Linwei Liu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (G.Z.)
| | - Pengfei Bai
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (G.Z.)
- Correspondence: ; Tel.: +86-13631401100
| | - Zichuan Yi
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China;
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (L.L.); (G.Z.)
- Academy of Shenzhen Guohua Optoelectronics, Shenzhen 518110, China
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11
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Yi Z, Zeng W, Ma S, Feng H, Zeng W, Shen S, Shui L, Zhou G, Zhang C. Design of Driving Waveform Based on a Damping Oscillation for Optimizing Red Saturation in Three-Color Electrophoretic Displays. MICROMACHINES 2021; 12:162. [PMID: 33562290 PMCID: PMC7915761 DOI: 10.3390/mi12020162] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 01/23/2023]
Abstract
At present, three-color electrophoretic displays (EPDs) have problems of dim brightness and insufficient color saturation. In this paper, a driving waveform based on a damping oscillation was proposed to optimize the red saturation in three-color EPDs. The optimized driving waveform was composed of an erasing stage, a particles activation stage, a red electrophoretic particles purification stage, and a red display stage. The driving duration was set to 360 ms, 880 ms, 400 ms, and 2400 ms, respectively. The erasing stage was used to erase the current pixel state and refresh to a black state. The particles' activation stage was set as two cycles, and then refreshed to the black state. The red electrophoretic particles' purification stage was a damping oscillation driving waveform. The red and black electrophoretic particles were separated by changing the magnitude and polarity of applied electric filed, so that the red electrophoretic particles were purified. The red display stage was a low positive voltage, and red electrophoretic particles were driven to the common electrode to display a red state. The experimental results showed that the maximum red saturation could reach 0.583, which was increased by 27.57% compared with the traditional driving waveform.
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Affiliation(s)
- Zichuan Yi
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
| | - Weibo Zeng
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
| | - Simin Ma
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
| | - Haoqiang Feng
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (S.S.); (G.Z.)
| | - Wenjun Zeng
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (S.S.); (G.Z.)
| | - Shitao Shen
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (S.S.); (G.Z.)
| | - Lingling Shui
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (S.S.); (G.Z.)
| | - Guofu Zhou
- South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (S.S.); (G.Z.)
| | - Chongfu Zhang
- College of Electron and Information, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402, China; (Z.Y.); (W.Z.); (S.M.); (W.Z.); (L.S.); (C.Z.)
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12
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Driving Waveform Design of Electrophoretic Display Based on Optimized Particle Activation for a Rapid Response Speed. MICROMACHINES 2020; 11:mi11050498. [PMID: 32423142 PMCID: PMC7281290 DOI: 10.3390/mi11050498] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/02/2020] [Accepted: 05/13/2020] [Indexed: 01/14/2023]
Abstract
Electrophoretic displays (EPDs) have excellent paper-like display features, but their response speed is as long as hundreds of milliseconds. This is particularly important when optimizing the driving waveform for improving the response speed. Hence, a driving waveform design based on the optimization of particle activation was proposed by analyzing the electrophoresis performance of particles in EPD pixels. The particle activation in the driving waveform was divided into two phases: the improving particle activity phase and the uniform reference grayscale phase. First, according to the motion characteristics of particles in improving the particle activity phase, the real-time EPD brightness value can be obtained by an optical testing device. Secondly, the derivative of the EPD brightness curve was used to obtain the inflection point, and the inflection point was used as the duration of improving particle activity phase. Thirdly, the brightness curve of the uniform reference grayscale phase was studied to set the driving duration for obtaining a white reference grayscale. Finally, a set of four-level grayscale driving waveform was designed and validated in a commercial E-ink EPD. The experimental results showed that the proposed driving waveform can cause a reduction by 180 ms in improving particle activity phase and 120 ms in uniform reference grayscale phase effectively, and a unified reference grayscale can be achieved in uniform reference grayscale phase at the same time.
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13
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Li W, Wang L, Zhang T, Lai S, Liu L, He W, Zhou G, Yi Z. Driving Waveform Design with Rising Gradient and Sawtooth Wave of Electrowetting Displays for Ultra-Low Power Consumption. MICROMACHINES 2020; 11:mi11020145. [PMID: 32012871 PMCID: PMC7074629 DOI: 10.3390/mi11020145] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 11/16/2022]
Abstract
As a kind of paper-like display technology, power consumption is a very important index for electrowetting displays (EWDs). In this paper, the influence of driving waveforms on power consumption of the EWDs is analyzed, and a driving waveform with rising gradient and sawtooth wave is designed to reduce the power consumption. There are three stages in the proposed driving waveform. In the initial stage, the driving voltage is raised linearly from the threshold to the maximum value to reduce the invalid power consumption. At the same time, the oil breakup can be prohibited. And then, a section of sawtooth wave is added for suppressing oil backflow. Finally, there is a section of resetting wave to eliminate the influence of charge leakage. Experimental results show that the power consumption of the ultra-low power driving waveform is 1.85 mW, which is about 38.13% lower than that of the conventional used square wave (2.99 mW), when the aperture ratio is 65%.
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Affiliation(s)
- Wei Li
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.L.); (T.Z.); (S.L.); (L.L.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Li Wang
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
- Academy of Shenzhen Guohua Optoelectronics, Shenzhen 518110, China
- Correspondence: or ; Tel.: +86-0755-29415855
| | - Taiyuan Zhang
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.L.); (T.Z.); (S.L.); (L.L.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Shufa Lai
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.L.); (T.Z.); (S.L.); (L.L.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Linwei Liu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.L.); (T.Z.); (S.L.); (L.L.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Wenyao He
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.L.); (T.Z.); (S.L.); (L.L.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
| | - Guofu Zhou
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, China; (W.L.); (T.Z.); (S.L.); (L.L.); (G.Z.)
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
- Academy of Shenzhen Guohua Optoelectronics, Shenzhen 518110, China
| | - Zichuan Yi
- Shenzhen Guohua Optoelectronics Tech. Co., Ltd., Shenzhen 518110, China;
- College of Electron and Information, University of Electronic Science and Technology of China, Zhongshan Institute, Zhongshan 528402, China
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14
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Xuan X, Qian S. Editorial for the Special Issue on Micro/Nano-Chip Electrokinetics, Volume II. MICROMACHINES 2018; 9:E383. [PMID: 30424316 PMCID: PMC6187532 DOI: 10.3390/mi9080383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 07/30/2018] [Indexed: 11/17/2022]
Affiliation(s)
- Xiangchun Xuan
- Department of Mechanical Engineering, Clemson University, Clemson, SC 29634, USA.
| | - Shizhi Qian
- Department of Mechanical and Aerospace Engineering, Old Dominion University, Norfolk, VA 23529, USA.
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