Hongmei Ma

Optimal rubbing angle for reflective in-plane-switching liquid crystal displays

Rubbing angle effects on the response time and optical threshold voltage of the reflective in-plane-switching homogeneous liquid crystal displays were analyzed. As the rubbing angle increases, the rise time decreases except that its operating voltage also increases. The optimal rubbing angle is around 30°–40°.

Pretilt angle effects on critical voltage and dynamic response of pi cell

The critical voltage with an arbitrary pretilt angle is given analytically which is consistent with the numerical results [Acosta et al., Liq. Cryst. 27, 977 (2000)]. The author’s results show that the critical voltage is dependent on the parameters of liquid crystal and pretilt angle but is independent of the cell gap. By numerical simulation the authors find that the on time of pi cell decreases with the increasing pretilt at the same voltage, and the off time of the cell driven by the undershoot method is much faster than that of the normal driven method for the cell with nonzero critical voltage.

Optimisation of in-plane-switching blue-phase liquid crystal display

For optimising the structure of in-plane-switching blue-phase liquid crystal display (IPS-BPLCD), we simulate voltage dependent transmittance curves of the cell with various cell gaps, electrodes’ gaps and electrodes’ widths, the optimised IPS-BPLCD structure with the low operate voltage, and a relatively high transmittance is obtained. The results should be useful to design IPS-BPLCD structure.

Reflective liquid-crystal display using an in-plane-switching super-twisted nematic cell

Two in-plane-switching (IPS) super-twisted nematic (STN) cells are proposed for reflective liquid-crystal displays. The IPS 180°-STN cell exhibits a normally black display with a relatively low-operating voltage, fast response time, and wide viewing angle. Potential applications for large screen reflective displays are foreseeable.

Blue-phase liquid crystal display with high dielectric material

ABSTRACT A blue-phase liquid crystal display (BPLCD) with low operating voltage and high transmittance is demonstrated by using a high dielectric material, which is used as an insulation layer or protrusion fixed on the pixel and common electrodes in in-plane switching (IPS) mode. The operating voltage is reduced to about 14 V and the transmittance is improved for the BPLCD with high dielectric constant protrusion. Compared with the conventional protrusion electrode structure, the proposed protrusion can make manufacturing process simple and easy because the electrode has no complex shape. The results will be significant in designing optimal BPLCDs. GRAPHICAL ABSTRACT

A Low Operating Electric Field Blue-Phase Liquid Crystal Display With Wedge Protrusion

A blue-phase liquid crystal display with wedge protrusion is proposed. The wedge protrusion is made of organic transparent material with a normal or high permittivity to support the inclined thin electrodes. By using this structure, the operating electric field can be less than 3.0 V/ μm when the cell gap is larger than 10 μm, and the normalized transmittance is about 80%. The low operating electric field helps to reduce hysteresis effect more, and the high transmittance means high light efficiency.

Reflective in-plane switching liquid crystal displays

The performance of a reflective in-plane switching (IPS) liquid crystal display is simulated by the parameter space method. The IPS electrodes and reflectors can be separately fabricated on the top and bottom substrates. The normally black reflective in-plane switching display shows wide viewing angle, high contrast ratio, weak color dispersion, and fast response time.

Twist angle effects on the dynamic response of in-plane-switching liquid crystal displays

Twist angle effects on the response time of in-plane-switching liquid crystal displays are analyzed. The authors propose a device configuration whose top and bottom boundary liquid crystal layers are symmetric to each other with respect to the electric field direction. The analytical results of this device configuration indicate that the response time is improved at least four times faster than that of a conventional in-plane-switching twisted-nematic mode and normal in-plane-switching mode.

Low-voltage blue-phase liquid crystal display with single-penetration electrodes

ABSTRACT A blue-phase liquid crystal display (BPLCD) with single–penetration (S-P) electrodes is proposed to reduce the operating voltage. X-shape inclined-electric field is induced by the S-P electrodes with 2 ~ 3 μm height, which can lower the operating voltage by ~45%, and improve the transmittance compared with BPLCD with conventional in-plane electrodes. Moreover, the wide viewing angle and very small image distortion index can be obtained in this structure with a half-wave biaxial film. The proposed structure shows simple etching control and easy one-drop filling process of blue-phase liquid crystal compared with dual-convex-penetration electrodes. GRAPHICAL ABSTRACT

Biaxial film design for full-colour, wide-view and high-contrast blue phase liquid crystal displays

To achieve full-colour, wide-view and high-contrast blue phase liquid crystal display (BPLCD), the compensated biaxial film is analysed in this paper. The dispersion of birefringence affects the light leakage of dark state and then affects the viewing angle and the contrast ratio at large polar viewing angle. Iso-transmission of dark state for BPLCD without compensational film, with conventional or wide-band biaxial film, is simulated. The simulated results show that the wide-band biaxial film is good for obtaining a BPLCD with excellent viewing angle and high-contrast ratio.