High performance liquid crystal displays with a low dielectric constant material

Abstract

We report high performance liquid crystal displays (LCDs), including fringe field switching (p-FFS) and in-plane switching (p-IPS), with a small average dielectric constant (ε) but positive dielectric anisotropy material. Our low ε based p-FFS and pIPS LCDs offer several attractive properties, such as high transmittance, low operation voltage, fast response time (even at −20°C), which is particularly desirable for outdoor applications of mobile or wearable display devices, and suppressed flexoelectric effect. Combining these advantages with the inherent outstanding features, such as wide viewing angle, no grayscale inversion, negligible color shift, and pressure resistance, the low ε LC based p-FFS and pIPS are strong contenders for next-generation mobile displays, and high resolution and high frame rate TVs.

A simple method to measure the twist elastic constant of a nematic liquid crystal

“…[1][2][3][4][5][6][7][8][9] In these LCDs, the electric field-induced LC reorientation takes place primarily in the horizontal direction. Therefore, their electro-optical characteristics, such as operation voltage and response time, are mainly governed by the twist elastic constant (K 22 ) instead of splay (K 11 ) or bend (K 33 ) elastic constants.…”

A Fringe Field Switching Liquid Crystal Display With Fast Grayscale Response Time

“…By setting at 10 , we are able to achieve the fastest decay time, which is 2.6 faster than that of conventional FFS mode (6.14 ms versus 16.22 ms). Moreover, if a material with reduced viscosity is employed [12], the cell gap can be further reduced and response time will become even shorter for PCFFS modes.…”

“…Compared to the rise process, which is driven by an electric field, the decay process is usually slower since it is mainly governed by the restoring elastic force. Because of the small , the decay time of a 3-m cell gap FFS LCD is usually 20 ms [12], which is too slow for TV applications. In contrast, the gray-to-gray (GTG) response time of a multi-domain vertical alignment (MVA) LCD TV is 5 ms [13], [14].…”

“…In contrast, the gray-to-gray (GTG) response time of a multi-domain vertical alignment (MVA) LCD TV is 5 ms [13], [14]. In order to reduce the response time of FFS mode, various approaches have been proposed, such as ultra-low viscosity LCs [12], double-side structures [15]- [17], reactive mesogen-aligned cells [18], [19], triode driving using a vertical field to expedite the decay process [20]- [22], etc. However, each approach has its own pros and cons.…”

Light Leakage of Multidomain Vertical Alignment LCDs Using a Colorimetric Model in the Dark State

“…Many conditions result in the light leakage such as light scattering from liquid crystals and the color filter, misalignment of crossed polarizers, and retardation of phase from liquid crystals [8,9]. Polarization light scattering from the liquid crystals due to thermally excited orientation-based fluctuations of liquid crystal directors and light depolarization from the color filter due to pigment scattering have to be discussed [10,11]. Investigating the colorimetric and photometric characteristics of LCDs, which include their major optical components, such as crossed polarizers, liquid crystals, color filters, and backlight modules, is interesting [12][13][14].…”