Chiral smectic A liquid crystals with large electroclinic coefficients and fast response times have been developed. The capability of achieving the optimum tilt angle of 22.5 degrees for applied fields less than 3V/micrometer, opens up the possibility developing silicon based high-resolution reflective displays without compromising on resolution and speed.

The photopolymer materials of poly(vinyl cinnamate) (PVCi) and polyimides showing homeotropic liquid crystal (LC) alignment have been used to control LC alignment on these films using linearly-polarized (LP)- UV exposure, and the LC alignment mechanism including pretilt angle generation on the films has been discussed. In the case of PVCi, an important contribution of non-dimerized side chains of PVCi molecules to the LC alignment is pointed out. On the other hand, LC alignment on homeotropically alignment polymer films exposed to LP-UV light is shown to be determined through the interaction of LC with alkyl branches attached to the polymer. It is also shown that the photo-alignment method using these photopolymer materials are very promising technique for the fabrication of some attractive LCD modes such as in-plane switching and vertically-aligned display modes, and an example of the application of the photo-alignment method to the fabrication of in-plane switching device is presented.

Gratings etched into polyimde thin layers are used to align nematic liquid crystals. The gratings are prepared by illumination of a 1.1 micrometer period phase mask with a KrF excimer laser at 248 nm. Fluences of 87 mJ cm^-2 and 128 mJ cm^-2 with one and two shots were used to ablate the gratings. Modelling of the fluence distribution behind the phase mask predicts a grating period equal to that of the phase mask and this is found experimentally. The amplitudes of the gratings are obtained from diffraction using a HeNe laser and are between 100 nm and 150 nm deep. The alignment layers are used in twisted nematic cells and the azimuthal anchoring energy is measured as a function of grating fabrication conditions. Anchoring energies of the order of 10^-5 J m^-2 are found in agreement with the Berreman theory.

Organic photorefractive materials have received increasing attention for photonic applications due to their high performance level and their ease of processing. Here, we preset functionalized polymer dispersed liquid crystals that exhibit strong photorefractive properties. Their properties are investigated by wave-mixing experiments and their performance compared with photorefractive polymers and photorefractive liquid crystals.

Space aberration effects which arise in high energy or in high average power laser chains are important parameters to control in order to emit a beam quality close to the diffraction limit. For that purpose we present recent experiments using an original adaptive and programmable module allowing the spatial control of the beam amplitude and the correction of the phase distortions due to the optical components and the gain media of the laser chain. Beam shaping is achieved by an optically addressed photoconductor-liquid crystal light valve. The light valve is addressed in the blue-green spectral range by incoherent projection of a VGA liquid crystal display. This adaptive optics module controls either the amplitude or the phase of near infrared laser beams depending on the liquid crystal operating mode. The other specific characteristics of the module will be detailed: no spurious diffraction effects, up to 10(pi) phase excursion and tri-lateral wavefront sensor. Experimental results of compensation of aberrations introduced on different laser beams will also be presented.

We have developed a new method for characterizing morphology of LCPC based on confocal fluorescence microscopy. Not only two-dimensional but also three-dimensional morphology of LCPC can be observed nondestructively by this method. The morphology of LCPC was consisted of liquid crystal and polymer phases, both of which are three-dimensionally continuous. Quantitative analysis of morphology was also made to clarify the relation between morphology and electro-optical characteristics. The local size of structure was obtained quantitatively from the perimeter of liquid crystal and polymer. It was found that the change in the value matched well with the change in morphology and it was related with the electro-optical characteristics.

A new type of holographic polymer dispersed liquid crystal (HPDLC) device in which liquid-crystal (LC) alignment is controlled by polymer layers has been developed. An LC containing light-curable prepolymer was placed between two substrates with anti-parallel alignment layers and cured using the interferential fringes of Ar⁺ laser light. Photo- polymerization occurred at the peaks of the interferential fringes and polymer networks were formed. LC layers formed at the nodes of the fringes. The LC molecules contained in the polymer layers were fixed so that they were aligned parallel to the substrates. Therefore, the polymer layers could be used to control the LC molecules in the LC layers and act as alignment layers. This alignment-controlled HPDLC device has a possibility to make effective use of the refractive index anisotropy of the LC. The fundamental operation of the alignment-controlled HPDLC device has been confirmed experimentally.

Positioned to replace current liquid crystal display technology in many applications, miniature information displays have evolved to provide several truly portable platforms for the world's growing personal computing and communication needs. The technology and functionality of handheld computer and communicator systems has finally surpassed many of the standards that were originally established for desktop systems. In these new consumer electronics, performance, display size, packaging, power consumption, and cost have always been limiting factors for fabricating genuinely portable devices. The rapidly growing miniature information display manufacturing industry is making it possible to bring a wide range of highly anticipated new products to new markets.

Reflective color STN-LCDs should be one of the most promising devices for mobile business tools (MBT), because the demand such as low cost, low power consumption, light weight and compact size is especially strong for this application. A reflective color STN-LCD with a single polarizer and double retardation films has been investigated. The double retardation films arranged in front of LC-layer enabled the LCD to contain reflective electrodes inside the panel. This configuration achieves the bright image with no parallax. A new construction of a reflective STN-LCD with a single polarizer has been decided by means of our own method in which the color difference (Delta) E* as the optimizing parameter has been used. Further, RGB color filters has been newly designed for our reflective LCD, and the aluminum (Al) layer has been introduced as reflective electrodes. As a result, we have realized 7.8-in.-diagonal refractive color STN-LCD(640 by 480) which has 15% reflectance, 1:14 contrast ratio, 4096 color capability and the sufficient color gamut. It has been confirmed that the single polarizer reflective color STN-LCD has sufficient enough performance for MBT use. We believe that it will be a key device for this application.

Electroclinic liquid crystals (ELCs) with their high speed, large contrast, gray scale response and large tilt angles at low operating voltages are highly attractive for use in AMLCDs featuring high frame rate, high resolution, and time sequential color. However, ELC response time usually rises significantly as the applied field is reduced, and has been found to increase as the cell gap is reduced for low operating voltage, high viewing angle devices. We investigate these effects using three alignment layers [polyimide, polybutylene terephthalate (PBT) and a photo-dimerized monolayer (PDML)] at several cell gaps and temperatures with a specific ELC. In the case of PBT we find that switching is faster than in the standard polyimide case. Furthermore, thin PBT cells switch faster than thick PBT cells. We also explore a novel single-sided PBT alignment layer scheme, made possible by the in-plane alignment and switching of ELCs. In such a cell, the response time levels off to a constant value at low applied fields, while alignment quality remains high. We conclude that the slowing of the ELC response with decreasing cell gap and decreasing applied field can be reduced substantially by the choice and number of alignment layers.

Twisted nematic liquid (TN) crystal structures have been widely employed to rotate the input polarization of the light by 90 degrees. For optimum performance, materials optimization is necessary for exact linear polarization rotation. By using Stokes parameter formalism, we derive the generalized relationship, which allows the calculations of the parameters that are necessary for arbitrary rotation of the linearly polarized light for twisted structures with arbitrary amounts of twist. We show that 'Gooch and Tarry' relation is a specialized case of our generalized results.

In this paper, we develop an incoherent optical correlator based morphological target recognition processor by using a SHARP QA-1200 8.4' active matrix TFT liquid crystal display (LCD) panel as two real-time spatial light modulators (SLM) for both the input and the reference image. The working principle and the structure design of the processor are illustrated. Some practical difficulties when using the LCD panel have been solved. Experimental results are given.

In this paper a novel method of realizing digital filters in an incoherent correlator is proposed in a shortly way. A novel gray-scale complementary encoding method is used to express the positive and negative numbers simultaneously. Digital filtering will be simplified into a convolution of the encoding images and filters followed by a subtraction operation. Based on the new method an Incoherent Optical Digital Filtering Unit (IODFU) is constituted. In the IODFU a liquid crystal spatial light modulator is used for displaying the gray-scale images to analyzed and the digital filters at the same time. All the images and filters can be changed by computer-controlling for different destinations. The IODFU is very compact and the processing speed can get to 12 frames per second. At the end of this paper the optical experiments are given.

Plastic substrates for the cells of displays exhibit only 1/6 of the weight of glass substrates; they are virtually unbreakable; their flexibility allows the designer to give them a shape suppressing reflections, to realize a display board on a curved surface or meeting the requirements for an appealing styling; displays with plastics are thinner which provides a wider viewing angle. These features render them attractive for displays in portable systems such as mobile phones, pagers, smart cards, personal digital assistants (PDAs) and portable computers. Reflective displays are especially attractive as they don't need a back light. The most important requirements are the protection of plastics against gas permeation and chemical agents, the prevention of layers on plastics to crack or peel off when the plastic is bent and the development of low temperature thin film processes because the plastics, as a rule, only tolerate temperatures below 150 degrees Celsius. Bistable reflective FLC- and PSCT-displays with plastic substrates will be introduced. Special sputtered SiO₂-orientation layers preserve the displayed information even if pressure or torsion is applied. MIM-addressed PDLC-displays require additional Al- or Ti-layers which provide the necessary ductility. Sputtered or PECVD-generated TFTs can be fabricated on plastics at temperatures below 150 degrees Celsius.

Bistable reflective cholesteric displays offer a solution for low power consumption displays. Image retention in zero field combined with inherent reflectivity (no need for backlighting) makes them ideal for applications such as portable document viewers. Here, we present an overview of the current research activities and achievements in this technology with focus on recent developments in white-on-black and stacked color displays, low cost drive electronics, video rate potential, and newly developed field induced polymer walls.