Recent development and application of TFT-LCDs using a-Si TFT are reviewed. An in-plane- switching (IPS) mode LCD is expected to be the most promising among many candidates for economically improving the poor-viewing angle in an LCD. Our practically-unlimited viewing-angle 14.5-inch IPS TFT-LCD prototype is described, which has XGA resolution and 64-gray-scale capability. An aircraft cockpit display requires a wide viewing-angle, wide operating-temperature, and high readability. Our large-size and full-color TFT-LCD under production as a cockpit display for new types passenger plane is described. A large-size reflective-color TFT-LCDs prototype fabricated through our high-aperture-ratio technology and minimized-production process is describe. A reflective TFT-LCD is very suitable for reducing power consumption. Additionally, performance and characteristics of other TFT- LCD prototypes and products are described.

We investigate the switching bistability based on the interaction between dynamic flow and director rotation in twisted nematic liquid crystal cells. Numerical calculation shows that there exists a general type of bistable twisted director configurations. Two specific cases are verified experimentally.

Electro-optical properties for light scattering liquid crystal displays (LCDs) prepared by using liquid crystalline monoacrylate, phenoxyl monoacrylate and alkyl monoacrylate as a component of monomer shave been investigated. The properties strongly depend on the chemical structure of monoacrylate. The liquid crystalline monoacrylate has effects to reduce the driving voltage and the hysteresis. The effect of the terminal group and the number of core-ring in the liquid crystalline monoacrylate on the driving voltage and the hysteresis is discussed. A memory phenomenon observed at low temperature is influenced by the chemical structure and the content of monoacrylate. The temperature dependence of the driving voltage and the hysteresis for the light scattering LCDs is discussed. Based on these result, a light scattering LCD with low driving voltage, small hysteresis and small temperature dependence has been achieved.

Reflective LCDs (RLCDs) have high brightness and are free from viewing parallax. They also cost less materials to construct and are compatible with existing manufacturing and driving practices. In this paper, a parameter space description of RLCD as a function of polarizer angle, liquid crystal twist angle and birefringence is discussed. It is shown that all published RLCD modes can be depicted in this parameter space, including the twisted-nematic- electrically controlled birefringence (TN-ECB) modes, the hybrid field effect mode, the mixed-mode TN, and the self-compensated TN (SCTN) mode. Additionally we show several new RLCD modes, including the reflective TN (RTN) and the reflective STN (RSTN) which can be obtained from searching the parameter space systematically. All RLCD modes are related by a variation of the 3 LCD parameters. The RTN and RSTN modes have applications to both direct view and projection display systems. Sample RTN and RSTN displays were fabricated. Experimental results show good agreement with theoretical predictions.

Flexible PDLC-based devices having 'all-plastic'-made transparent electrodes were developed. Unlike the relatively non-flexible ITO-based electrodes, their polymer counterparts are mechanically flexible, allowing the fabrication of flexible devices. Other advantages of devices containing a conducting polymer are the reduction in operating energy consumption and the anticipated reduction in their manufacturing costs.

A new method for achievement of a uniform liquid crystal alignment in conventional sandwich cells is proposed. The method is based on the interaction between a highly anisotropic liquid crystal thermoset material, used as an aligning layer, and liquid crystal. An important advantage of the method is that the contact surface of the alignment layer with the liquid crystal, contrary to the conventional aligning techniques using buffed polymer films, is not subjected to any mechanical treatment before the cell assembling and thus being entirely defect-free. The alignment layers based on anisotropic liquid crystal thermosets are especially important in the case of ferroelectric liquid crystal devices where the surface defects are playing a crucial role.

We describe the design and performance of a color real-time autostereoscopic 3D display based on our partial pixel 3D display architecture. The primary optical components are an active-matrix liquid crystal display and a diffractive optical element overlay. The display operates at video frame rats and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images.

Manipulation of light by light as a stimulus by the use of liquid-crystalline materials was explored, which was aimed at optical switching, optical image storage and optical display. Two types of the liquid-crystalline materials are used: nematic liquid crystals and ferroelectric liquid (FLCs). Several kinds of optical switching and image storage systems were demonstrated by means of photochromic molecules and photosensitive LC alignment layer to induce the change in alignment of the LCs: 1) Fast nematic to isotropic phase transition of azobenzene LCs was induced by the laser pulse in two modes of analysis, transmission mode and reflection mode. 2) Optical switching in FLCs doped with the azobenzene was investigated with regard to photochemical flip of polarization of the FLCs. 3) Optical control of polymer- dispersed LC was explored by means of the azobenzene LC. 4) Optical switching and fabrication of nonrubbed alignment layer based on the novel photophysical principle was achieved in terms of photosensitive polyimide as an LC alignment layer. 5) Optical control of conductivity was performed by the use of LC thiophene derivatives.

This paper describes basic concepts of liquid crystal spatial light modulators, basic considerations for applying them in optical information processing system, some applications, and their future directions.

A novel optical storage media based on the optical alignment of liquid crystals is reviewed. The high birefringence of the liquid crystal combined with the high spatial and angular control of the liquid crystal orientation using light can lead to new, high capacity, optical storage media. Our work demonstrating that monomeric optically aligned liquid crystal can be subsequently photopolmerized to form stable polymer films further allows for the use of this technology for read-only storage media. Issues regarding the advantages and disadvantages of these potential storage media will be discussed.

We show that a nematic liquid crystal acted on by a laser field is an apparently simple physical system that, however, undergoes variety of complex dynamic phenomena. We have studied the dynamics of the NLC-reorientation in a homeotropic NLC-cell in a laser beam. The nature and features of observed phenomena are essentially determined by the geometry of interaction. For normal incidence of the light beam, we have found that the knowledge of the speed of reorientation is needed to fully characterize the transition of the system form the unstable to the stable equilibrium. In the case of oblique incidence of light, the director can start persistent oscillations that become irregular and evolve towards a chaotic dynamics in a particular range of the light intensity.

The second harmonic generations (SHG) of liquid crystalline main-chain type polymers were investigated. The sample polymers are copolymers of 2-hydroxy-6-naphthoic acid (HNA) with 4-hydroxy-benzoic acid, in various composition ratios. The SHG of the film samples was greatly affected not only by the polymerization conditions, but also by preparation conditions of the films. SHGs for the samples processed by mechanical stretching and for electrically poled samples were compared. The nonlinear optical coefficients d_exp evaluated by Maker Fringe method of the electrically poled samples are 2-3 times larger than that of the mechanically oriented same whose d_exp is about 5pm/V. The high SHG of the main-chain type NLO polymers mainly originates from the additivity of hyperpolarizeability of the individual unit due to head to tail bonding.

New liquid crystals of nonchiral, banana shaped molecules are investigated by generation of the second harmonic of an optical wave. Symmetry properties of the apparent thermodynamic phases are studied and first quantitative values of the nonlinear optical coefficients are given.

IR z-scan and conoscopic measurements have been performed on dye-doped nematic liquid crystal samples to investigate the influence of the dopant on the orientational nonlinear response of the liquid crystalline material, and the result compared to undyed samples. Both the dye-doped and undyed samples were prepared utilizing a surface treatment which produces homeotropic alignment in the undyed, glass-substrate samples. For samples constructed with non-conducting substrates, the dopant only slightly strengthens the nonlinear response of the host material, and the response in all cases is less than half that observed in samples with ITO- coated substrates. Undyed samples displayed no response at normal incidence for the laser intensities used, regardless of substrate, while doped samples displayed significant self- limiting at all angles of incidence. Increasing the dopant concentration further enhances the observed responses, but the time required to achieve the initial alignment state of the nematic increases more rapidly than the response, and significant delays in response to pulsed inputs are also observed. Laser polarization strongly effects the response characteristics, as expected. Z-scan and conoscopic measurements are used to determine the origin of the unusually large response in the ITO-coated samples Initial efforts with conoscopic techniques have found no evidence of pre-tilt in the director orientation, though more sensitive measurements are in process. The presence of a large nonlinear absorption contribution due to the dopant has been observed, though why only ITO-substrate samples may be affected is still under investigation.

There exist many studies for measuring the viscoelastic properties with the Frederiks transition of nematic liquid crystal sin an external field. It usually needs to measure the threshold field before measuring the viscoelastic properties. This study introduces the method of measuring the scattering of nematic liquid crystals with evanescent-wave to get the threshold field since it can make sure the anchoring condition. The result for the elastic constants and twist viscosity (gamma) are reported and compared with the data from the liquid crystals supplier.

The liquid crystal adaptive lens (LCAL) is an electro-optical device whose focal length can be varied electrically. The discrete nature of the electrodes of the device introduces phase aberrations which degrade the performance of the LCAL. We introduce a novel electrode architecture, called 'conductive ladder meshing' (CLM) and a 'stimulated annealing' voltage dithering technique to reduce the phase aberrations. True imaging experiments with a spherical CLM LCAL were performed for a single incoming polarization under white light illumination. Experimental results revealed that the image formed wee comparable to those formed by a fixed lens in terms of resolution,although, the contrast was worse. In addition o variable focal lengths, the CLM LCAL is capable of image translation orthogonal to the propagation direction.

Uniaxial crystal properties can easily be obtained by using a nematic liquid crystal (LC) with suitable substrate treatment.A liquid crystal lens, which has bifocal properties, is fabricated wit a concave lens and a pane substrate to attain a convex lens shape LC layer, and is used as the key component of the double focusing interferometer. Liquid crystal materials are selected for the refractive index matching between the plano-concave lens and n_o value of the LC material. In this case, an incident ordinary ray as a test beam passes just through the lens without focusing. On the other hand, an extraordinary ray as a reference beam is focusing on the test piece with the same general path, and the common path configuration can easily be achieved. Basic properties as a novel optical test system using the LC lens are demonstrated, and it is confirmed that a thickness of an Al evaporated film can successfully be measured by introducing phase shifting technique.

Compensated imaging by real-time holography corrects for aberrations in telescope imaging systems and allows scaling to large apertures using lightweight, low-optical-quality primary mirrors. This application leads to unique requirements for optically addressed liquid-crystal spatial light modulators.

Switchable holograms offer the possibility of real-time electro-optical control of diffractive optic components. We have recently demonstrated recording of diffractive optic components. We have recently demonstrated recording of transmission holographic Bragg gratings in a material system consisting of a photoinitiator dye, co-initiator, a chain extender, a multifunctional acrylate and a low molecular weight nematic liquid crystal. Low voltage scanning electron microscopy studies have shown that the gratings consist of periodic polymer-dispersed liquid crystal (PDLC) planes. Electrical switching of a first order Bragg diffracted beam into the zero-order with an applied field of 10 V/micrometers was observed. Addition of a surfactant to the pre-polymer syrup reduces the switching field to approximately 5 V/micrometers . Fast response times of the order of microseconds were observed for switching and relaxation. In this paper, we have demonstrated the concept of a switchable guided substrate-mode coupler by writing a slanted transmission grating. The diffracted light form this grating is trapped in a glass slab by total internal reflection. The added electrical switchability of PDLC grating allows for the effective control of the intensity and position for light into or out of the substrate.

Recent theoretical and experimental results have shown that the orientational photorefractive effect seen in doped nematic liquid crystal films gives rise to strong beam amplification effects without suffering from phase crosstalk. These effects, examined for both four and two wave mixing, are well suited for adaptive optics applications.

The anamorphic liquid crystal (LC) microlens are prepared using elliptically-patterned electrode structures and nematic LC materials, and their optical properties are demonstrated. The interference fringe patterns of the LC microlens can be varied by applying voltages. Focal length and astigmatic focal distance properties are estimated as a function of applied voltage and it is confirmed that an astigmatism of the anamorphic LC microlens can easily be controlled by an ellipticity of a patterned electrode and an applying voltage. Coupling of a laser diode beam to a multimode optical fiber is also demonstrated using the anamorphic LC microlens.

Mechanisms of index control and dynamic gratings for single mode waveguides are reviewed. Electronically switchable Bragg gratings based on holographic polymerized polymer/liquid crystal composites stand out as a promising materials for waveguide and fiber optic applications with large index modulations, low intrinsic scattering, adequate switching speeds, and low cost grating formation. This combination of properties is not shared by semiconductors, electro-optic crystals or polymers, or bulk liquid crystal films.

Liquid crystal (LC) materials possessing the chiral smectic A phase have been designed to yield high induced tilt angels and low response times. The primary objective of our work is to design materials that can provide the optimum tilt angle of 22.5 degrees for applied voltages less than 5V/micrometers , making them CMOS compatible Optical response measurement to illustrate the feasibility of obtaining 256 gray levels are presented. The gray scale capability of the material is visually demonstrated using a 1 X 64 array driven by a dc balanced circuit.