Toward Suppressing Oil Backflow Based on a Combined Driving Waveform for Electrowetting Displays

Long, Zhengxing; Yi, Zichuan; Zhang, Hu; Lv, Jiahua; Li, Liming; Chi, Feng; Shui, Lingling; Zhang, Chongfu

doi:10.3390/mi13060948

Cited by 7 publications

(8 citation statements)

References 33 publications

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“…where V th is the threshold voltage of the oil film, L pixel is the unit length of the pixel in EWDs, and h oil and ε oil are the height and the dielectric constant of the oil film, respectively. It can be seen that the threshold voltage of oil film rupture is related to the dielectric constant, oil film height, pixel size, and other factors [35]. The degree of oil film rupture depends on the applied driving voltage.…”

Section: Oil Film Splittingmentioning

confidence: 99%

A Driving Waveform with a Narrow Falling and High-Voltage Reset Structure for Improving the Stability of Electrowetting Displays

Long

Wang

et al. 2023

Coatings

Self Cite

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An electrowetting display (EWD) is a new reflective display device with the advantages of paper display, high reflectivity, and fast response times. However, the display performance of EWDs has been restricted by oil film splitting and luminance oscillation. Therefore, a new driving waveform based on a falling slope function and a high-voltage, square-wave reset signal is proposed to solve these defects. It consists of a shrinkage stage and a stabilizing stage. First, the oil film of a pixel can be quickly ruptured by applying a falling slope function during the shrinkage stage according to the oil film-splitting theory. Then, a direct current (DC) voltage is applied to promote the complete fusion of the dispersed oil films by analyzing the voltage characteristic curves of EWDs. Finally, a high-voltage, square-wave reset signal is applied during the stabilizing stage to reduce luminance oscillations and suppress oil film backflow. Experimental results show that the average luminance was increased by 6.5% compared with a PWM driving waveform. The display stability of EWDs was improved by 89.1% compared with a driving waveform with a rising gradient.

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Section: Oil Film Splittingmentioning

confidence: 99%

A Driving Waveform with a Narrow Falling and High-Voltage Reset Structure for Improving the Stability of Electrowetting Displays

Long

Wang

et al. 2023

Coatings

Self Cite

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“…On the contrary, when the aperture ratio decreases as the voltage decreases, the contact angle is called receding angle at the same driving voltage and the difference between the forward and backward angles is the contact angle hysteresis in EWDs [11]. The square waveform is applied during the driving process to keep the aperture ratio, this method can not only shorten the response time but also improved the oil splitting [25]. When the driving voltage increases to a maximum, the oil will be shrank completely in corners, the aperture ratio cannot be larger.…”

Section: Principles Of Ewdsmentioning

confidence: 99%

A high integration electrowetting displays system based on AC driving model

Xu¹,

Zhan²,

Liu³

et al. 2022

Front. Phys.

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As a representative of new reflective display technology, the electrowetting display (EWD) has been widely accepted for its good advantages in power consumption control and display contrast. Because of charge trapping and contact angle hysteresis, static images cannot be maintained and afterimage phenomenon occurs, respectively. These problems seriously affect the EWDs display effect. In order to improve the video display effect of EWDs, an alternating current (AC) driving model was proposed in this paper. Firstly, a high integration EWDs system was built with Xilinx field programmable gate array (FPGA). Secondly, an asymmetric intermediate frequency (IF) AC driving model was proposed to eliminate the afterimage of the video. Finally, the optimized driving method was applied to the EWDs system to achieve a high-smooth display output. The experimental results showed that the problem of afterimage and the problem of static image preserving display were effectively solved. Compared with the traditional AC driving waveform, the maximum reflected luminance of the proposed method was increased by 14%, and the refresh rate of EWDs could reach 60 Hz.

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“…Electrowetting display (EWD) is a new reflection display technology, boasting high contrast, ultra-low power consumption, and fast response [ 1 , 2 ]. However, the commercialization of EWD still needs to be improved, due to oil backflow problems [ 3 ], as well as gray scale consistency and other issues [ 4 ]. Driving waveform is a voltage sequence which can drive pixels to display gray scales in EWDs.…”

Section: Introductionmentioning

confidence: 99%

Design of Multi-DC Overdriving Waveform of Electrowetting Displays for Gray Scale Consistency

Wang

Zhang

et al. 2023

Micromachines

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Gray scale consistency in pixels was extremely important for electrowetting displays (EWDs). However, traditional electrowetting display driving waveforms could not obtain a pixel aperture ratio consistency, which led to the occurrence of gray inconsistency even if it was the same driving waveform. In addition, the oil backflow caused by charge trapping could not be sustained. Therefore, a multi-direct current (DC) overdriving waveform for gray scale consistency was proposed in this paper, which could effectively improve the performance of EWDs. The driving waveform was divided into a start-up driving phase and a stable driving phase. The stable driving phase was composed of a square wave with a duty cycle of 79% and a frequency of 43 Hz. Subsequently, an overdriving pulse was also introduced in the stable driving phase. The multi-DC driving waveform for gray scale consistency was applied to a thin film transistor-electrowetting display (TFT-EWD). The average difference between increasing driving voltage and decreasing driving voltage was only 2.79%. The proposed driving waveform has an aperture ratio of 3.7 times at low voltages compared to DC driving.

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Toward Suppressing Oil Backflow Based on a Combined Driving Waveform for Electrowetting Displays

Cited by 7 publications

References 33 publications

A Driving Waveform with a Narrow Falling and High-Voltage Reset Structure for Improving the Stability of Electrowetting Displays

A Driving Waveform with a Narrow Falling and High-Voltage Reset Structure for Improving the Stability of Electrowetting Displays

A high integration electrowetting displays system based on AC driving model

Design of Multi-DC Overdriving Waveform of Electrowetting Displays for Gray Scale Consistency

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