Review Paper: Emerging vertical‐alignment liquid‐crystal technology associated with surface modification using UV‐curable monomer

Abstract— The recent development of polymer‐induced pretilt angle in multi‐domain vertical‐alignment liquid‐crystal (LC) structures is reviewed. To create a small but well‐defined pretilt angle, ～0.1 wt.% of a photo‐curable monomer was mixed in an LC host and a bias voltage was applied to reorient the LC directors within each domain. The monomers are polymerized near the substrate surfaces by UV exposure. The formed polymer layers change the surface pretilt angle of the LC from 90° to about 89° with a defined azimuthal orientation. Consequently, within each domain the LC reorientation direction responding to the external field is well‐defined which leads to faster rise time and higher transmittance. This new technology overcomes the long standing problems of conventional MVA devices and is therefore expected to play a dominant role in the future.     

A fast‐switching OCB‐mode LCD for high‐quality display applications

Abstract— Optically compensated bend (OCB) mode is a promising technology, due to its wide range of viewing angles without gray‐scale inversion or color shift, fast response, high contrast ratio, and wide temperature range. This paper summarizes the fundamental characteristics of OCB mode and discusses the development of field‐sequential‐color displays and 3‐D displays for future high‐quality display applications.     

Requirements for large‐sized high‐resolution TFT‐LCDs

Abstract— A 22‐in. prototype TFT‐LCD with a resolution of 200 pixels per inch and wide‐viewing‐angle capability has been developed and its requirements in terms of screen quality and technology will be discussed. An in‐plane‐switching mode with dual‐domain structure, post‐spacers, and high‐resolution process were implemented to achieve superior front‐of‐screen quality. And, also, in order to improve reliability and productivity, we developed a new injection method for liquid crystals which enabled us to eliminate injection holes.     

Deformed nanostructure of photo‐induced biaxial cholesteric films and their application in VA‐mode LCDs

Abstract— Novel biaxial retardation films made from photo‐induced deformed cholesteric liquid‐crystal (LC) nanostructures using reactive mesogen mixtures (RMMs) for a viewing‐angle compensation of vertically aligned liquid‐crystal displays (VA‐LCDs) was developed. The deformed cholesteric LC nanostructure has been observed by X‐ray‐diffraction (XRD) measurement. The birefringence of the film was described well by our optical model based on a form birefringence theory. The VA‐LCDs with photo‐induced biaxial cholesteric films have excellent viewing‐angle properties.     

Fault detection and isolation for nonlinear systems via high‐order‐sliding‐mode multiple‐observer

In this paper, fault detection and isolation problems are studied for a certain class of nonlinear systems. Under some structural conditions, multiple high‐order sliding‐mode observers are proposed. The value of the equivalent output injection is used for detecting faults and the multiple‐model approach for isolating particular faults in the system. The proposed method provides fast detection and isolation of actuator and plant faults. Simulation results support the proposed approach. Copyright © 2014 John Wiley & Sons, Ltd.     

A 470 × 235‐ppi poly‐Si TFT‐LCD for high‐resolution 2‐D and 3‐D autostereoscopic displays

Abstract— We have developed a 470 × 235‐ppi poly‐Si TFT‐LCD with a novel pixel arrangement, called HDDP (horizontally double‐density pixels), for high‐resolution 2‐D and 3‐D autostereoscopic displays. 3‐D image quality is especially high in a lenticular‐lens‐equipped 3‐D mode because both the horizontal and vertical resolutions are high, and because these resolutions are equal. 3‐D and 2‐D images can be displayed simultaneously in the same picture. In addition, 3‐D images can be displayed anywhere and 2‐D characters can be made to appear at different depths with perfect legibility. No switching of 2‐D/3‐D modes is necessary, and the design's thin and uncomplicated structure makes it especially suitable for mobile terminals.     

Reduced‐order design of high‐order sliding mode control system

To design an rth (r>2) order sliding mode control system, a sliding variable and its derivatives of up to (r ? 1) are in general required for the control implementation. This paper proposes a reduced‐order design algorithm using only the sliding variable and its derivatives of up to (r ? 2) as the extension of the second‐order asymptotic sliding mode control. For a linear time‐invariant continuous‐time system with disturbances, it is found that a high‐order sliding mode can be reached locally and asymptotically by a reduced‐order sliding mode control law if the sum of the system poles is less than the sum of the system zeros. The robust stability of the reduced‐order high‐order sliding mode control system, including the convergence to the high‐order sliding mode and the convergence to the origin is proved by two Lyapunov functions. Simulation results show the effectiveness of the proposed control algorithm. Copyright © 2010 John Wiley & Sons, Ltd.     

An adaptive solution for robust control based on integral high‐order sliding mode concept

A new high‐order sliding mode controller is proposed. The main features are gain adaptivity and the use of integral sliding mode concept. The gain adaptation allows a reduction of the chattering and gives a solution to control uncertain nonlinear systems whose the uncertainties/perturbations have unknown bounds. The concept of real high‐order sliding mode detector is introduced given that it plays a key role in the adaptation law of the gain. This new control approach is applied by simulation to an academic example to evaluate its efficiency. Copyright © 2014 John Wiley & Sons, Ltd.     

A 100,000‐cd/m2 capacity‐coupled electrodeless discharge backlight with high efficacy for LC TVs

A capacity‐coupled electrodeless Hg discharge lamp has been developed for LC TV backlightings. By applying sinusoidal voltages which are 180° out of phase with a pair of external electrodes, a luminous uniformity of over 84% is attained in two types of lamps whose lengths are 190 and 390 mm. Luminance, efficacy, and input power to the lamp are 114,000 cd/m², 35 lm/W, and 21.5 W when the 390‐mm lamp is driven at 5 MHz. With a frequency below 1.1 MHz, eight 390‐mm lamps, connected in parallel to one another without external ballast impedance, can be driven by using a single inverter.     

A new pixel design and a novel driving scheme for multi‐domain vertically aligned LCDs

Abstract— By using a new pixel design and a novel driving scheme that adds a bias electrode and a bias TFT to the ordinary pixel structure, a high‐contrast‐ratio and wide‐viewing‐angle LCD mode, refered to as the biased vertical‐alignment (BVA) mode, has been sucessfully developed. Compared to the published data on the PVA and MVA modes, the BVA mode has a distinct advantage of lower manufacturing cost due to the elimination of a lithographic process step that forms either ITO cuts or protrusions on the color‐filter substrates. The BVA mode requires ITO cuts on the TFT substrate similar to that for the PVA and MVA modes. The 15‐in. BVA‐mode XGA prototype exhibits a high contrast ratio of 1200:1 and high cell transmittance of 4.3%.     

A high‐aperture‐ratio and low‐crosstalk pixel structure design for in‐plane‐switching‐mode TFT‐LCDs

Abstract— The TFT‐LCD market is growing rapidly, and the replacement of CRT TV by LCD TV requires the implementation of LC modes with wide viewing angles and high brightness. The IPS mode is an excellent technology to realize wide viewing angles, but it has a low aperture ratio that has now been improved by Advanced Super‐IPS (AS‐IPS). In this paper, we propose a novel pixel structure design that not only increases the aperture ratio but also reduces the crosstalk. We have improved the current AS‐IPS aperture ratio by 1.25 times and effectively reduced the capacitive coupling ratio from 1.2% to 0.05%.     

A new generation of high‐efficiency red‐emitting electroluminescent devices with exceptional stability

Abstract— Red‐emitting organic electroluminescent devices have been developed that provide exceptional stability, efficiency, and color chromaticity, and which operate at a lower drive voltage. We have identified several superior host‐dopant systems, which, to the best of our knowledge, provide devices with outstanding performance. These devices show projected operational lifetimes (20 mA/cm²), under an ambient temperature, of >25,000 hours and 2000–8000 hours at elevated temperatures (85 and 70°C).     

A new non‐linear sliding‐mode torque and flux control method for an induction machine incorporating a sliding‐mode flux observer

In this paper a novel sliding‐mode control algorithm, based on the differential geometry state‐co‐ordinates transformation method, is proposed to control motor torque directly. Non‐linear feedback linearization theory is employed to decouple the control of rotor flux magnitude and motor torque. The advantages of this method are: (1) The rotor flux and the generated torque can be accurately controlled. (2) Robustness with respect to matched and mismatched uncertainties is obtained. Additionally, a varying continuous control term is proposed. As a result, chattering is eliminated without sacrificing robustness and precision. The control strategy is based on all motor states being available. In practice the rotor fluxes are not usually measurable, and a sliding‐mode observer is derived to estimate the rotor flux. The observer is designed to possess invariant dynamic modes which can be assigned independently to achieve the desired performance. Furthermore, it can be shown that the observer is robust against model uncertainties and measurement noise. Simulation and practical results are presented to confirm the characteristics of the proposed control law and rotor flux observer. Copyright © 2004 John Wiley & Sons, Ltd.     

Output feedback stabilization using super‐twisting control and high‐gain observer

An output feedback controller is designed for a class of uncertain nonlinear systems with relative degree higher than one. A super‐twisting sliding mode state feedback controller is designed and implemented using a high‐gain observer. It is proved that the controller achieves practical stabilization and the ultimate bound can be reduced by decreasing a design parameter. The performance of the controller is illustrated by simulation.     

Slot loading effect on impedance and radiation performance of high‐gain patch antenna under TM03‐mode operation

Based on antenna's impedance and radiation performance, the slot loading effect on the TM₀₃‐mode high‐gain square patch antenna is investigated in this paper. Three different slot configurations are loaded to the patch along the central line, which can reduce the sidelobe in the E‐plane. However, it is found that the H‐plane beamwidth, impedance bandwidth and radiation Q factor become significantly different in these cases. At first, broader H‐plane beamwidth, lower Q factor and wider impedance bandwidth can be obtained when only single slot is loaded in the center of the patch. In contrast, when two open slots are etched at two nonradiative edges of the patch, it will result in narrower H‐plane beamwidth, higher Q factor and narrower impedance bandwidth. Moreover, better balanced performance can be achieved by simultaneously loading the central and sided slots. For validation, three kinds of antenna prototypes are designed, fabricated, and measured. The measured and simulated results agree well with each other, which demonstrate that different impedance and radiation performance can be freely adjusted and achieved by using different slot configurations.     

Disturbance attenuation with fast global finite‐time convergence for generalized high‐order uncertain nonlinear systems

This paper focuses on the problem of disturbance attenuation with fast global finite‐time convergence (FTC) for a class of generalized high‐order uncertain nonlinear systems. Combining the fast finite‐time stabilization technique with a delicate manipulation of sign functions, a new control approach is proposed to attenuate the serious uncertainties substantially, including time‐varying control coefficients, nonlinear parameters, and external disturbances, while achieving the performance evaluated in terms of L₂‐L_2p gain. A notable feature of the control strategy is the fast FTC, which greatly shortens the convergent time when the initial state is far away from the origin. A numerical example is provided to demonstrate the effectiveness of the proposed method.     

Discrete‐time higher‐order sliding mode control of systems with unmatched uncertainty

The research on discrete‐time higher‐order sliding mode has received a considerable attention recently. Systems with unmatched uncertainties are common in practice; however, the existing discrete‐time higher‐order sliding mode control algorithms are designed considering only matched uncertainty. This paper proposes a technique to design discrete‐time higher‐order sliding mode control for an uncertain LTI system in the presence of unmatched uncertainty. The proposed technique is numerically simulated and experimentally validated on an electromechanical rectilinear plant. Various experiments are conducted considering the several operational conditions of electromechanical systems in industries to verify the performance of the proposed controller.     

A unified approach to finite‐time stabilization of high‐order nonlinear systems with and without an output constraint

This paper considers the problem of state feedback finite‐time stabilization for a class of high‐order nonlinear systems with an output constraint. By proposing a novel tan‐type barrier Lyapunov function combined with manipulating sign functions, the technique of adding a power integrator is skillfully revamped to develop a systematic approach that guides us to construct a state feedback finite‐time stabilizer for high‐order nonlinear systems while preventing the violation of a prespecified output constraint during operation. The proposed approach is a unified tool in the sense that it can provide a finite‐time stabilizer design even when the constraint is infinite, or equivalently, there is no need for a constraint. A simple example is presented to demonstrate the effectiveness of the proposed strategy.     

Containment analysis and design for high‐order linear time‐invariant singular swarm systems with time delays

Containment analysis and design problems for high‐order linear time‐invariant singular swarm systems on directed graphs with time delays are investigated. To eliminate impulse terms in singular swarm systems and ensure that the singular swarm systems can achieve containment, time‐delayed protocols are presented for leaders and followers, respectively. By model transformation, containment problems of singular swarm systems are converted into stability problems of multiple low‐dimensional time‐delayed systems. In terms of linear matrix inequality, sufficient conditions are presented for time‐delayed singular swarm systems to achieve containment, which are independent of the number of agents. By using the method of changing variables, an approach is provided to determine the gain matrices in the protocols. Numerical simulations are shown to demonstrate theoretical results. Copyright © 2012 John Wiley & Sons, Ltd.     

A silicon‐chip‐based light valve with reflective twisted‐nematic mode for high‐definition projectors

Crystalline‐silicon‐chip‐based reflective light valves are suitable for realizing high definition and bright liquid‐crystal projectors. We have developed an XGA (1025 × 769 pixels) silicon‐chip‐based light valve with a diagonal display area of 2.54 cm (1 in.). The reflective twisted‐nematic mode was examined by using the Jones matrix method as a display mode, and the normally white reflective twisted‐nematic mode was selected. This mode is suitable for a narrow cell gap, and a fast response time can be expected. In addition, the driving voltage of this mode is low and has good chromaticity with small retardation. The cell gap of the light valve is 2 μm. The cell gap support is made using spacer posts formed on the silicon chip with a photodefinable resin. The response time is 12 msec, including both rise and fall times. The contrast ratio is more than 1000 at 5 Vrms.