scholarly journals Improving Electrophoretic Particle Motion Control in Electrophoretic Displays by Eliminating the Fringing Effect via Driving Waveform Design

Micromachines ◽  
2018 ◽  
Vol 9 (4) ◽  
pp. 143 ◽  
Author(s):  
Shitao Shen ◽  
Yingxin Gong ◽  
Mingliang Jin ◽  
Zhibin Yan ◽  
Chang Xu ◽  
...  
Keyword(s):  
Motion Control ◽  
Particle Motion ◽  
Waveform Design ◽  
Driving Waveform

scholarly journals A Separated Reset Waveform Design for Suppressing Oil Backflow in Active Matrix Electrowetting Displays

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 491
Author(s):  
Linwei Liu ◽  
Pengfei Bai ◽  
Zichuan Yi ◽  
Guofu Zhou
Keyword(s):  
Experimental Data ◽  
Dielectric Layer ◽  
Waveform Design ◽  
Second Phase ◽  
Active Matrix ◽  
Two Phases ◽  
Back Stage ◽  
A Charge ◽  
Electric Field Force ◽  
Driving Waveform

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.

scholarly journals Closed-Loop Particle Motion Control Using Laser-Induced Thermocapillary Convective Flows at the Fluid/Gas Interface at Micrometric Scale

2018 ◽  
Vol 23 (4) ◽  
pp. 1543-1554 ◽  
Author(s):  
Ronald Terrazas Mallea ◽  
Aude Bolopion ◽  
Jean-Charles Beugnot ◽  
Pierre Lambert ◽  
Michael Gauthier
Keyword(s):  
Motion Control ◽  
Particle Motion ◽  
Closed Loop ◽  
Convective Flows

scholarly journals Driving Waveform Design of Electrowetting Displays Based on an Exponential Function for a Stable Grayscale and a Short Driving Time

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 313 ◽  
Author(s):  
Zichuan Yi ◽  
Zhenyu Huang ◽  
Shufa Lai ◽  
Wenyao He ◽  
Li Wang ◽  
...  
Keyword(s):  
Time Constant ◽  
Exponential Function ◽  
Waveform Design ◽  
Hysteresis Curve ◽  
Optimal Time ◽  
Driving Voltage ◽  
Aperture Ratio ◽  
Driving Time ◽  
Long Time ◽  
Driving Waveform

The traditional driving waveform of the electrowetting display (EWD) has many disadvantages, such as the large oscillation of the target grayscale aperture ratio and a long time for achieving grayscale. Therefore, a driving waveform based on the exponential function was proposed in this study. First, the maximum driving voltage value of 30 V was obtained by testing the hysteresis curve of the EWD pixel unit. Secondly, the influence of the time constant on the driving waveform was analyzed, and the optimal time constant of the exponential function was designed by testing the performance of the aperture ratio. Lastly, an EWD panel was used to test the driving effect of the exponential-function-driving waveform. The experimental results showed that a stable grayscale and a short driving time could be realized when the appropriate time constant value was designed for driving EWDs. The aperture ratio oscillation range of the gray scale could be reduced within 0.95%, and the driving time of a stable grayscale was reduced by 30% compared with the traditional driving waveform.

An Electrophoretic Display Driving Waveform Design for Reducing a Flicker and a Driving Time Based on the Fusion Optimization of Driving Stages

2021 ◽  
Vol 16 (3) ◽  
pp. 351-356
Author(s):  
Li Wang ◽  
Yi-Fan Zhang ◽  
Ji-Tao Zhang ◽  
Qi-Ming Wan ◽  
Peng-Chang Ma
Keyword(s):  
Waveform Design ◽  
Experimental Results ◽  
Gray Scale ◽  
High Quality ◽  
Look Up Table ◽  
Driving Time ◽  
Electrophoretic Display ◽  
Human Eyes ◽  
Driving Waveform ◽  
Main Factor

The speed of updating an image is very important for an electrophoretic display (EPD) application, but the flicker which can be produced among the process of updating an image is a main factor of affecting reading comfort for human eyes. In this paper, a new driving waveform, which was based on DC balance, was proposed to reduce the number of flicker and decrease the driving time for updating an image. Firstly, we studied properties of particles in the EPD, and the stages in the driving waveform were fused according to the driving properties of the particles. Secondly, an accurate reference was formed in the driving waveform for writing a new image, and the particle activity was guaranteed at the same time. Lastly, the driving waveform was downloaded to a real EPD waveform look-up table and the performance was compared with traditional driving waveforms. Experimental results showed that the proposed driving waveform could reduce flicker effectively and shorten the driving time by 25%, and an accurate white reference gray scale was obtained for displaying high quality images.

An adaptive generation method for electrophoretic display driving waveform design

2016 ◽  
Vol 24 (11) ◽  
pp. 676-685
Author(s):  
Fei-Bo Duan ◽  
Peng-Fei Bai ◽  
Alex Henzen ◽  
Ling-Ling Shui ◽  
Biao Tang ◽  
...  
Keyword(s):  
Waveform Design ◽  
Electrophoretic Display ◽  
Driving Waveform

scholarly journals Design of Driving Waveform for Shortening Red Particles Response Time in Three-Color Electrophoretic Displays

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 578
Author(s):  
Wenjun Zeng ◽  
Zichuan Yi ◽  
Xichen Zhou ◽  
Yiming Zhao ◽  
Haoqiang Feng ◽  
...  
Keyword(s):  
Power Consumption ◽  
Response Time ◽  
Particle Motion ◽  
Low Power Consumption ◽  
Gray Scale ◽  
Experimental Platform ◽  
Common Electrode ◽  
Scale Optimization ◽  
Driving Waveform ◽  
Electrode Plate

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.

scholarly journals Driving Waveform Design Based on Driving Process Fusion and Black Reference Gray Scale for Electrophoretic Displays

2021 ◽  
Vol 9 ◽  
Author(s):  
Li Wang ◽  
Pengchang Ma ◽  
Jitao Zhang ◽  
Qiming Wan
Keyword(s):  
Waveform Design ◽  
Low Power Consumption ◽  
Gray Scale ◽  
Strong Light ◽  
Ultra Low Power ◽  
Second Stage ◽  
Driving Time ◽  
Display Technology ◽  
Two Stages ◽  
Driving Waveform

An electrophoretic display (EPD) is a kind of paper display technology, which has the advantages of ultra-low power consumption and readability under strong light. However, in an EPD-driving process, four stages are needed to finish the driving of a pixel erase original images, reset to black state, clear-to-white state, and write a new image. A white reference gray scale can be obtained before writing a new image, and this driving process may take too long for the comfort of reading. In this article, an EPD-driving waveform, which takes the black state as the reference gray, is proposed to reduce the driving time. In addition, the rules of direct current (DC) balance are also followed to prevent the charge from getting trapped in the driving backplane. The driving process is fused and there are two stages in the driving waveform: reset to black state and write the next image. First, the EPD is written to a stable black state according to the original gray scale driving waveform and the black state is used as the reference gray for the next image. Second, the new image is written by the second stage of the new driving waveform. The experimental results show that the proposed driving waveform has a better performance. Compared with the traditional driving waveform which has four stages, the driving time of the new driving waveform is reduced by nearly 50%.

Study on driving waveform design process for multi-nozzle piezoelectric printhead in material-jetting 3D printing

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yih-Lin Cheng ◽  
Tzu-Wei Tseng
Keyword(s):  
3D Printing ◽  
Design Process ◽  
High Speed ◽  
Hold Time ◽  
Maximum Velocity ◽  
Waveform Design ◽  
Droplet Velocity ◽  
Content Type ◽  
Satellite Drops ◽  
Driving Waveform

Purpose Material-jetting (MJ) three-dimensional (3D) printing processes are competitive due to their printing resolution and printing speed. Driving waveform design of piezoelectric printhead in MJ would affect droplet formation and performance, but there are very limited studies on it besides patents and know-hows by commercial manufacturers. Therefore, in this research, the waveform design process to efficiently attain suitable parameters for a multi-nozzle piezoelectric printhead was studied. Therefore, this research aims to study the waveform design process to efficiently attain suitable parameters for a multi-nozzle piezoelectric printhead. Design/methodology/approach Ricoh’s Gen4L printhead was adopted. A high-speed camera captured pictures of jetted droplets and droplet velocity was calculated. The waveforms included single-, double- and triple-pulse trapezoidal patterns. The effects of parameters were investigated and the suitable ones were determined based on the avoidance of satellite drops and preference of higher droplet velocity. Findings In a single-pulse waveform, an increase of fill time (Tf) decreased the droplet velocity. The maximum velocity happened at the same pulse width, the sum of fill time and hold time (Tf + Th). In double- and triple-pulse, a voltage difference (Vd) above zero in the holding stage was adopted except the last pulse to avoid satellite drops. Suitable parameters for the selected resin were obtained and the time-saving design process was established. Research limitations/implications Based on the effects of parameters and observed data trends, suggested procedures to determine suitable parameters were proposed with fewer experiments. Practical implications This study has verified the feasibility of suggested design procedures on another resin. The required number of trials was reduced significantly. Originality/value This research investigated the process of driving waveform design for the multi-nozzle piezoelectric printhead. The suggested procedures of finding suitable waveform parameters can reduce experimental trials and will be applicable to other MJ 3D printers when new materials are introduced.

scholarly journals A Fast-Response Driving Waveform Design Based on High-Frequency Voltage for Three-Color Electrophoretic Displays

Micromachines ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 59
Author(s):  
Hu Zhang ◽  
Zichuan Yi ◽  
Liming Liu ◽  
Feng Chi ◽  
Yunfeng Hu ◽  
...  
Keyword(s):  
Response Time ◽  
High Frequency ◽  
Response Times ◽  
Fast Response ◽  
Waveform Design ◽  
Optimal Frequency ◽  
Polar Solvents ◽  
Flexible Display ◽  
Performance Response ◽  
Driving Waveform

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.

scholarly journals Driving Waveform Design of Electrophoretic Display Based on Optimized Particle Activation for a Rapid Response Speed

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Wenyao He ◽  
Zichuan Yi ◽  
Shitao Shen ◽  
Zhenyu Huang ◽  
Linwei Liu ◽  
...  
Keyword(s):  
Inflection Point ◽  
Response Speed ◽  
Waveform Design ◽  
Testing Device ◽  
Activity Phase ◽  
Particle Activation ◽  
Two Phases ◽  
Motion Characteristics ◽  
Driving Waveform ◽  
Brightness Curve

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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