Flexoelectric in-plane switching (IPS) mode with ultra-high-transmittance, low-voltage, low-frequency, and a flicker-free image

Abstract

The demands for a power-saving mode for displaying static images are ubiquitous not only in portable devices but also in price tags and advertising panels. At a low-frequency driving in liquid crystal displays (LCDs) for low-power consumption, the flexoelectric effect arises even in calamitic liquid crystals and the optical appearance of this physical phenomenon is found to be unusually large, being noticed as an image-flickering. Although the inherent integrated optical transmittance of in-plane switching (IPS) mode is relatively lower than that of fringe-field switching (FFS) mode, the IPS mode shows no static image-flickering but an optical spike (the so-called optical bounce), at the transient moment between signal positive and negative frames. Here, we demonstrate an IPS mode using negative dielectric anisotropy of liquid crystals (Δε < 0) and fine-patterned electrodes (the width w of and the space l between electrodes ≤ 3 μm) with reduced operation voltage (up to 40.7% to a conventional FFS mode with Δε < 0), reduced optical bounce (up to 4.4%. to a conventional FFS mode with Δε < 0) and enhanced transmittance (up to 32.1% to a conventional IPS mode with Δε > 0). We believe the result will contribute not only to the scientific understanding of the optical appearance of flexoelectric effect but also pave the way for engineering of a superior low-power consumption LCD.

Image flickering reduction by dimer and polymer stabilization in FFS liquid crystal display

“…In order to use a low driving frequency to save energy, the image flickering problem must be solved. [9][10][11][12][13][14] In a previous paper, we showed that ionic effect and flexoelectric effect are the 2 factors responsible for the image flickering in FFS LCD. 15 Ions may cause 2 problems.…”

“…However, if the driving frequency is reduced, there is a problem that the brightness of the display may change with time, a phenomenon known as image flickering. In order to use a low driving frequency to save energy, the image flickering problem must be solved . In a previous paper, we showed that ionic effect and flexoelectric effect are the 2 factors responsible for the image flickering in FFS LCD .…”

P‐152: High resolution and ultra ‐ fast switching liquid crystal device for Virtual Reality Display

“…On the other hands, LCDs have some advantage in making high resolution over 1000 ppi but have some disadvantage in displaying moving pictures because its response time is relatively slow compared to the emissive type displays and still have difficulty in achieving high resolution over 2000 ppi. LCDs for VR displays are based on fringe-field switching (FFS) mode because of its high aperture ratio, high transmittance, low operation voltage and touch-screen tolerance [2][3][4][5][6]. To achieve fast response time in FFS mode or in-plane switching (IPS) mode many approaches are introduced.…”

P‐149: Maximization of Transmittance and Minimization of Image‐Flickering due to Flexoelectric Effect in Low‐Frequency Driving Fringe‐Field Switching (FFS) Mode Using LCs with Negative Dielectric Anisotropy

“…The flexoelectric effect is a phenomenon, which is a coupling between electric polarization and mechanical distortion. According to Meyer's analysis, the polarization induced by flexoelectric effect can be determined as P f = e 11 n( •n)+e 33 n ( n), where e 11 and e 33 are splay and bend flexoelectric coefficients, respectively, and n is a unit vector of LC orientation [11][12][13][14][15]. Fig.…”