The surface modification characteristics of liquid crystal (LC) alignment layers irradiated with various argon (Ar) ion beam (IB) energies were investigated as a substitute for rubbing technology. Various pretilt angles were created on the IB-irradiated polyimide (PI) surfaces after IB irradiation, but the Ar ions did not alter the morphology on the PI surface, indicating that the pretilt angle was not due to microgrooves. The chemical bonding states of the IB-irradiated PI surfaces were analyzed in detail by x-ray photoelectron spectroscopy to verify the compositional behavior for the LC alignment. Chemical structure analysis showed that the alignment ability of LCs was due to the preferential reorientation of the carbon network due to the breaking of C=O double bonds in the imide ring parallel to the incident IB direction. The potential of applying nonrubbing technology to display devices was further supported by the superior electro-optical characteristics compared to rubbed PI.

We have studied the liquid crystal (LC) alignment and tilt angle generation of a nematic liquid crystal (NLC) on a homeotropic polyimide (PI) surface using a new ion beam source. The tilt angle of the NLC on the homeotropic PI surface for all incident angles is about 38 and this angle has a stabilization trend. A good LC alignment of the NLC on the homeotropic PI surface by to exposure ion beam of 45 incidence angle was observed. Also, the tilt angle of the NLC on the homeotropic PI surface by to exposure ion beam of 45 incidence angle had a tendency to decrease as ion beam energy density increased. Thus, we demonstrated that the tilt angle could be controlled from vertical to horizontal directions. Also, the alignment character of the NLC on the homeotropic PI surface with respect to ion beam energy was good at more than 1500 eV. Finally, a superior LC alignment thermal stability on the homeotropic PI surface subject to ion beam exposure was achieved.

This paper introduces the vertically aligned twisted nematic in-plane switching (VPS) structure, and compares the electro-optical (EO) characteristics of VPS liquid crystal displays (LCDs) and in-plane switching (IPS) LCDs. Various VPS-LCD pretilt angles were induced, and ion beam (IB) irradiation was used to enhance the EO properties. An x-ray photoelectron spectroscopic analysis of the IB-irradiated polymer surface confirmed that the intensity of C=O bonding as a function of exposure time traced the pretilt angles. The pretilt angle effect on optical properties was first analyzed in the experimental results. While multidomain vertical alignment LCDs and IPS-LCDs only resolve one difficulty, the VPS-LCDs described here overcome several viewing angle and transmittance curve problems.

Nematic liquid crystal (NLC) alignment effects on SiN x thin film layers treated by ion-beam irradiation for three types of N ratio were successfully studied for the first time. The SiN x thin film was deposited by plasma-enhanced chemical vapor deposition using three types of N ratio. To characterize the film, atomic force microscopy was performed. Good LC aligning capabilities on the SiN x thin film treated by ion-beam irradiation for all N ratios can be achieved. The low pretilt angle for an NLC on the SiN x thin film treated by ion-beam irradiation was observed and could be adopted in planar alignment liquid crystal display applications as in-plane switching and fringe-field switching modes.

We investigated the use of nickel oxide (NiO) as a catalyst for the metal-induced crystallization. SiNx serves as a diffusion filter that forms an effective barrier to Ni and also acts as a passivation layer for metal contaminants. The NiO has a constant area density of 8.22×106 Ni atoms  cm−2. This allows enough depletion regions for the growth of disklike grains. The thin film transistor exhibited a field-effective mobility of 15.9cm2V−1s−1, a threshold voltage of −5.2V, an Ion∕Ioff ratio of 1.6×107, and a gate voltage swing of 0.8V∕decade.