Electro-Optical Property in Hybrid Aligned Reverse mode Cell Using Liquid Crystals with Positive and Negative Dielectric Constant Anisotropies

Abstract

We have proposed polymer stabilized liquid crystal (LC) cells with a hybrid alignment nematic (HAN) LC. LCs with positive and negative dielectric constant anisotropies are used. The cell has a reverse mode electro-optical property which shows a transparent state in a voltage off-state and a light scattering state in the on-state. We fabricate cells by irradiating the cell with a UV light from a planar alignment side or vertical alignment side in a polymerization process. The photopolymerization-induced segregation of the polymer from the LC and the influence of UV absorption by the LC bulk are investigated. A relationship between UV irradiation conditions and electro-optical characteristics in the cell is clarified. The light scattering intensity depends on an incident angle of light in the on-state, which is promising for application to smart windows. The feasibility of this concept is demonstrated with consideration of LC materials.

Driving Voltage in Reverse Mode Cell Using Reactive Mesogen : Effect of UV Absorption of Liquid Crystal

“…Figure 6 shows a schematic model of the polymer structure with large and small LC domains. It is well known that the weak UV intensity makes large LC domains in the PDLC system [16][17][18][19][20]. When the UV intensity decreases with passing through the LC bulk, the LC domain size becomes lager.…”

Angular Dependence of Guest–Host Liquid Crystal Devices with High Pretilt Angle Using Mixture of Vertical and Horizontal Alignment Materials

“…Devices with a unique angular dependence were demonstrated by control of liquid crystal (LC) polar angles. Among them, a device that exhibits a difference in transmittance depending on whether the angle of incidence is positive or negative was developed using a hybrid alignment nematic (HAN) LC [1], a polymer dispersed LC (PDLC) [2,3], a hybrid twisted nematic (HTN) LC [4], and a guest-host HAN LC [5]. The louver function can be achieved using HAN-type liquid crystals, but it is necessary to apply a voltage to control the angle with the highest transmittance.…”

Hybrid-Aligned Liquid Crystal Polymers Adhered to the Polarizing Film or Doped with Dichroic Dye for Display Privacy Protection

“…It is worth mentioning that, as far as we know, both LCD screens and most OLED screens emit linearly polarized light (LPL) because they contain polarizers inside them. , Leveraging this characteristic, preparing thin films of anisotropic materials with angle-dependent transmittance for LPL could be an appealing idea. In recent years, liquid crystals (LCs) and polymer dispersed LCs (PDLCs) units with hybrid alignment have shown promising applications in various fields, such as smart windows and displays, thanks to their optical anisotropy induced by special orientation. − Among these, some research has proposed that a sandwich structure consisting of a small-molecule LC cell with a hybrid arrangement and polarizers can reduce light transmittance at predetermined azimuth and polar angles without affecting the transmission of light in the normal direction. This configuration has demonstrated potential applications in angle-switching LCDs and one-dimensional light field-shaping windows. ,, However, this requires two additional layers of polarizers, and the integration of a small-molecule LC cell adds extra thickness and weight, which is unfavorable for industrial commercialization.…”