Progress in Advanced Properties of Electrowetting Displays

Abstract

Electrowetting display (EWD) has promising prospects in the electronic paper industry due to it having superior characteristics, such as the ability to provide a comfortable reading experience and quick response. However, in real applications, there are also problems related to dielectric deterioration, excess power consumption, optical instability and narrow color gamut etc. This paper reviewed the existing challenges and recent progress made in terms of improving the optical performance and reliability of EWD. First, the principle of electrowetting applied in small and confined configurations is introduced and the cause of the failure of the dielectric layer is analyzed. Then, the function of the pixel structures is described to avoid display defects. Next, electric signal modulations are compared in terms of achieving good image quality and optical stability. Lastly, the methods are presented for color panel realization. It was concluded that multi-layer dielectrics, three-dimensional pixel structures, proper electric frequency-and-amplitude modulation and an RGB color panel are expected to resolve the current limitations and contribute to designing advanced reflective displays.

Anion Intercalation into Graphite Drives Surface Wetting

“…The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/jacs.2c13630. Materials and chemicals, preparation of the electrodes, electrowetting setup configuration, PTFE cell configuration, synthesis and NMR spectra ( 1 H, 13 C, 19 F, and 7 Li) of EMIM-TFSI, surface tension and mass density measurements, electrochemical measurements, calculation of capacitance from electrochemical impedance measurements, contact angle measurements, in situ Raman spectroscopy measurements, predicting the electrowetting response using the Y−L equation, contact angle variations upon deep intercalation/deintercalation in EMIM-TFSI, surface electrochemistry of LiClO 4(PC) in hexadecane, interfacial surface tension and work of adhesion at the liquid−liquid interface, dynamic measurements in the biphasic systems, electrowetting under AC in the biphasic systems, optical images of the droplets at selective potential biases for the systems under study, and electrowetting performance of selected biphasic systems reported in the literature (PDF) Changes in apparent contact angle during 200 wetting/ dewetting cycles for a 1 M LiClO 4(PC) droplet on HOPG in air (MP4) Changes in apparent contact angle at the EMIM-TFSI| HOPG interface in air upon application of a constant potential pulse for 200 s at +1.7 V with subsequent stepping to 0 V (MP4) Changes in apparent contact angle at the 20 m LiTFSI (aq) |HOPG interface in air upon application of a constant potential pulse for 200 s at +0.8 V with subsequent stepping to 0 V (MP4) Changes in apparent contact angle during 200 wetting/ dewetting cycles following the protocol described in the Experimental Section, for a 1 M LiClO 4(PC) droplet on HOPG in hexadecane (MP4) Changes in apparent contact angle during 200 wetting/ dewetting cycles following the protocol described in the Experimental Section, for a 20 m LiTFSI (aq) droplet on HOPG in hexadecane (MP4)…”

“…Wetting phenomena are ubiquitous, underpinning physicochemical processes occurring in both nature and artificial systems. Even their simple macroscopic observation can provide significant molecular insights into the properties of interfaces as well as those of the adjoining bulk phases. − A number of diverse technologies, from electrochemical energy conversion, storage , and capacitive deionization (CDI) , to variable optics, − displays, , and lab-on-a-chip systems, , are driven by wetting processes which occur under the application of an external electric field, a phenomenon referred to as electrowetting . Controlling wettability under these conditions is of paramount importance for product design, since any variations in wettability can have significant implications for the operation of the devices (such as lack of adhesion, , hysteresis, − and loss of electrochemical activity − ), resulting in performance decrease and/or failure.…”

3.1: Invited Paper: Electrowetting display: Towards full‐color video reflective display

“…By reducing the oil film thickness, the aperture can reach 80%. While narrow down the pixel size and pixel wall thickness, the resolution can reach 250ppi [31] .…”

Influence of the Ground Electrode on the Dynamics of Electrowetting

“…Electrowetting is used in several applications, such as micro-drop generation, mixing and splitting [ 1 , 2 ], high-speed droplet actuation [ 3 , 4 ], chip cooling [ 5 ], drug release and clinical diagnosis [ 6 , 7 ], e-paper and electronic display [ 8 , 9 ], energy harvesting [ 10 ], solar indoor lighting [ 11 ], optics and beam steering [ 12 , 13 ]. In most electrowetting studies, the primary focus has been to observe the drop deformation and contact-angle change when the applied voltage is varied.…”