Switching molecular or supramolecular systems reversibly from one state to another, with both states having significantly different properties using light is widespread in biological systems and has been in the focus of materials research for many years. Such synthetic systems are promising as high density data storage systems, sensors, photonic switches or as molecular logic gates. There the concept of optically addressable molecules promises miniaturisation to the molecular level and potentially the direction towards optical computing on that level. Our approach is based on the concept that the functional groups and the properties in such molecules, if suitably selected can add up to attractive properties in the self-assembled molecular systems. Rational design allows of the photochromic core and the mesogenic groups for the modulation of the photochromic behaviour, the absorption properties, the quantum yields of the photo conversion processes and the conversion obtained at the photostationary state. The use of suitable mesogens allows for the use of the FRET effect for the switching behaviour.

The birefringence of some different monomesogen and bimesogen liquid crystals has been determined. Birefringence is an important liquid crystal property in the context of display and optical communication applications. Members of the well known homologous series of liquid crystals nOCB were measured for comparison with a series of cyanobiphenyl bimesogens containing a novel fluorinated mesogenic group and novel conjugated ring structures. Comparative measurements were made by a rotating analyser technique, using a Helium-Neon laser as an illumination source. We present the birefringence and phase characterisation for several different liquid crystal materials, inferring structure-property relations and the effect of forming a bimesogen.

The paper describes an enhancement of the electroclinic characteristics of low molar mass dimeric organosiloxane liquid crystals. The degree of polymerisation of the siloxane core unit was varied in order to study the effect on phase transitions and electro-optic properties. It was found that the SmA*-SmC* phase transition temperature could be moved to any position in the range from 50°C to 10°C if we varied the number of SiMe₂ groups in the flexible linkage of the dimeric molecule. More importantly, because the organosiloxane liquid crystal material had some distribution of the number of SiMe₂ groups, it showed a rather broad SmA*-SmC* phase transition in contrast to the sharp phase transition of conventional electroclinic materials. The electroclinic coefficient reached the maximum value of 8 degrees/V/μm and was at least 1 degree/V/μm over a temperature range as broad as 10°C. The induced electroclinic tilt angle was as high as 22-23 degrees with good linearity and moderate applied electric fields.

We have recently shown that bimesogenic liquid crystals exhibiting chiral nematic and smectic (SmA, SmA* or C*) phases have macroscopic electro-optic properties that make them very interesting for both display and non-display applications. Since materials have been synthesised where the optical effect observed could be due to scattering power, birefringence, dichroism, fluorescence and optical-nonlinearity (SHG and THG), and where the principle optical axis can be rotated in any direction through 90° in times of the order of microseconds at moderate fields, i.e., 1-10V per micron, then this suggests an exciting variety of new optoelectronic applications. In this paper we will describe nanoscopic design protocols, molecular templating effects and the molecular properties important for these systems. Specifically we will consider bimesogenic SmC* incorporating siloxane linking groups that exhibit either ferroelectric or anti-ferroelectric phases depending on the number of silicon atoms in the siloxane moiety using the same mesogens. The siloxane configuration leads to a molecular template effect observed on the macroscopic scale as synclinic or anticlinic phases. Unusually these materials have cone angles of up to and including 90º which makes them ideal for high contrast displays, phase elements, photonics transducers and lasers.

Novel tunable polarization interference filters (PIF) employing active liquid crystal devices are presented, and the principles of operation are described. Filter designs are presented based on a requirement for tunable nulls in the visible and near infrared spectral regions, of high optical density, for protection from intense electromagnetic radiation outside of the spectral range of interest which can saturate an imaging or sensor system. Two types of PIFs are presented with their modeled results and device performances. Analog filters in a generalized Lyot-Ohmann geometry are presented which are capable of tuning an optical null through 260 nm, by employing a single active device per filter stage. Binary filters are also presented which can switch between two complimentary and non-overlapping spectral states. Both types of filter can operate in a “normally on” state with a broadband “white light” throughput.

We demonstrate a fast optical modulator capable of switching large amount of optical retardation (a few microns) in less than 1 ms. The result is achieved by employing a dual frequency nematic in cells with high pre-tile alignment and by providing a special addressing scheme that features amplitude and frequency modulated voltage. We explore the effect of time delay and dielectric heating in process of the optical retardation switching.

Inhomogeneous nanoscale polymer-dispersed liquid crystal (PDLC) devices having gradient nanoscale droplet distribution were fabricated. This gradient refractive index nanoscale (GRIN) PDLC film was obtained by exposing the LC/ monomer with a uniform ultraviolet (UV) light through a patterned photomask. The monomer and LC were mixed at 70: 30 wt% ratio. The area exposed to a weaker UV intensity would produce a larger droplet size, and vice versa. Owing to the nanoscale LC droplets involved, the GRIN PDLC devices are highly transparent in the whole visible region. The gradient refractive index profile can be used as switchable prism gratings, Fresnel lens, and positive and negative lenses with tunable focal lengths. Such a GRIN PDLC device is a broadband device and independent of light polarization. The diffraction efficiency of the lens is controllable by the applied voltage. The major advantages of the GRIN PDLC devices are in simple fabrication process, polarization-independent, and fast switching speed, although the required driving voltage is higher than 100 V_rms. To lower the driving voltage, the technique of polymer-networked liquid crystal (PNLC) has been developed. The PNLC was also produced by exposing the LC/monomer mixture with a uniform UV light through a patterned photomask. However, the monomer concentration in PNLC is only around 2-5 wt%. The formed PNLC structure exhibits a gradient polymer network distribution. The LC in the regions stabilized by a higher polymer concentration exhibits a higher threshold voltage. By using this technique, prism grating, tunable electronic lens and Fresnel lens have been demonstrated. The driving voltage is around 10 V_rms. A drawback of this kind of device is polarization dependence. To overcome the polarization dependence, stacking two orthogonal homogeneous PNLC lens is considered.

The free thin nematic liquid crystal (NLC) layers applied on the surface and observed in polarizing microscope are being used in the science and high technologies for structural inhomogeneities detection on the surface of materials. Simplicity, efficiency and high sensitivity have given an opportunity of NLC application in cancer detection. There were three stages in our investigations. 1. It was discovered that on malignant tissues of animals and human beings NLC have homeotropic orientation while on benign tissues they have planar or tilted orientation. 2. The discovered phenomenon was explained by the surface tension value difference on malignant and benign tumors. 3. The difference in surface tension is based on the particularities of the different parts of the interface layer. The “water” on the boundary with malignant tissues has higher order parameter in comparison with benign tissue. The difference in order parameter was explained by higher concentration of the protein and less concentration of lipids in the “water” on malignant tissues. As the result the anchoring NLC energy on the surface of structural water is higher in comparison with benign tissue. In the first case the NLC have homeotropic orientation in the whole volume of NLC layer while in the second case the surface Fredericks transition is observed.

We discuss examples involving the development of ordered polymer thin films for application as light bending devices. This paper focus on the preparation of ordered polymer architectures using self-assembled or field-induced optical patterns of various liquid crystal hosts for imprinting or templating polymer or functional materials. The various images of ordered polymer are provided by the polarized optical microscopy (POM) and scanning electron microscopy (SEM) study. Slantwise UV irradiation technique was applied for the formation of the asymmetric polymer patterns. Various UV irradiation angles were used and significant differences in the polymer patterns with respect to the applied angle were observed. Transmission grating patterns are investigated. The electro-optical measurements for the analysis of patterned cells will be presented.

Dynamic secondary ion mass spectrometry (SIMS) is usually applied to measure depth profiles in inorganic multi-layer systems. SIMS on organic multi-layer samples is highly complicated due to the complex fragmentation of the sample which results in fingerprint of masses representing the components in the sample. Using multivariate statistics, we succeeded to interpret the SIMS spectra and were able to identify layers with different compositions in artificially produced two-layer samples. The method is demonstrated for samples of a poly(isobornylmethacrylate) coating on a polymer dispersed liquid crystal consisting of the nematic liquid crystal (E7) and poly(isobornylmethacrylate). Quantification of the E7 concentration is complicated by evaporation in the vacuum system. Infrared spectroscopy proved that the loss of E7 from poly(isobornylmethacrylate) can be prevented by capping the sample with poly(vinyl alcohol). Cooling to cryogenic temperatures will be required to suppress further evaporation during SIMS analysis. The SIMS depth resolution of a two-layered sample was determined by discriminant function analysis to be 130 nm at a depth of one micrometer, which allows the application of SIMS for a typical optical grating.

Plastic passive matrix (PM) and active matrix (AM) electronic paper displays (EPDs) have been prepared by SiPix’s Microcup roll-to-roll manufacturing processes using ITO/PET films. The Microcup displays have shown outstanding environmental stability and excellent physico-mechanical properties such as scratch, impact and flexure resistances even in high temperature and humidity conditions. A PMEPD recently prepared on inexpensive row-and-column patterned ITO/PET films has shown a contrast ratio of ≥10, t_on ≤30 msec at ≤40 V, and a threshold voltage of ≥15 V. More than 8 levels of grayscale with outstanding bistability have been demonstrated by either pulse width or pulse count modulation. No noticeable degradation of the mid-tone images has been observed even after the power was turned off for more than 5 days. Moreover, the electro-optical responses, particularly the threshold voltage and gamma of the PMEPDs remain essentially the same within a wide range (20-60°C) of operation temperature.

In many applications, the presence of domain walls limits the performance of liquid crystal displays (LCDs) in terms of brightness, contrast and response speed. Examples are found in wide-viewing-angle LCDs in which each pixel contains domains with different director orientations. Microscope measurements of various types of LCDs are presented and compared with the results of advanced two- and three-dimensional simulations. The background of the modeling programs is reviewed, especially if new methods are used. One example is that of a double-domain twisted-nematic (TN) LCD configuration that was made using photo-alignment. The shape of the domain wall and its effect on the transmitted intensity are described correctly by simulations. In another example it is shown that the experimental results for in-plane switching (IPS) structures can be understood with the help of advanced optical simulation methods that take into account diffraction effects. In a final example, the occurrence of domain walls in liquid crystal on silicon (LCoS) is discussed.

A geometrical optics approach (GOA) to the optics of the nematic liquid crystals whose optic axis (director) varies in two or three space dimensions is presented. Two examples of the GOA applications are considered: calculation of light transmittance (1) through a liquid crystal (LC) film with two-dimensional (2D) director which combines the concepts of in-plane switching and vertical alignment, and (2) through a three-dimensional (3D) LC cell associated with a homeotropic to multidomainlike transition (HMD cell). Important details of the GOA applications for both cases are described. The GOA results are compared with those obtained from the quasi-one-dimensional Jones calculus and the beam propagation method (BPM) where the latter is applicable. Comparison between the results of different methods of calculating the near zone electromagnetic field (the radiation at points just on the exit of the analyzer) as well as the far zone diffraction pattern is provided. It is found that the GOA is about as fast as the Jones method for calculating optical properties of LC films with any number of dimensions of director variations, yet the GOA has the advantage of being more accurate than the Jones calculus.

A unique electro-optical behavior in the “chiral smectic C phase” liquid crystal cell is introduced in conjunction with possible interpretation of the specific molecular initial alignment. This cell shows continuous gray shades capability with keeping fast optical response such as less than 100 ms at room temperature. This gray shade has hysteresis-free, which suggests possible shielding of spontaneous polarization in the cell. Asymmetrical optical response between rise and decay profiles with very small temperature dependence strongly suggests the shielding of polarization in the cell. Therefore, this particular cell may be called as the polarization shielded smectic liquid crystal display or the PSS-LCD. The unique electro-optical response phenomena and their interpretation are discussed here.

Electro-optic characteristics of a twisted nematic (TN) liquid crystal display (LCD) fabricated by doping Ag nanoparticles protected with NLC, 5CB (K-15, Merck) molecules has been investigated and it is shown that the device exhibits a unique electrooptic response characteristics that is sensitive to the high frequency component of the operating voltage together with the conventional root-mean-square response to the operating voltage. We call this device frequency modulation (FM) TN-LCD. The FM TN-LCD is switched by switching the frequency of the operating voltage while its amplitude is kept unchanged. As an example, by switching the frequency from 20Hz to 500Hz or 50Hz to 2kHz, and the switching is done with the time constant of several ms. This device shows a peculiar response to a burst AC square voltage waveforms, where the device exhibits bipolar response with the time constant of 500 ms and the envelope with the time constants shorter than those of an undoped TN-LCD by from 30% to 80%. The mechanism of the FM-TN-LCD is investigated through the study of its dielectric properties.

The authors have developed two types of wide color gamut monitor and compared their characteristics. This paper provides an introduction to the color reproduction and standard color space of displays as well as an interpretation of the two types of typical wide color gamut displays that are currently under development. The CRT displays with a wide color gamut are rich in gray levels and viewing angle characteristics while the LCD displays with a LED backlight style have high brightness performance and a broad color gamut. Both types of display support the color gamut of Adobe RGB, enabling compatibility with the extended color space, now beginning to be disseminated, and they also provide a breakthrough for industries that need color management.

Using the Berreman 4x4 method we developed a simulation program to study the effects of cell structure parameters of a liquid crystal optical switch based on total internal reflection. The study shows that the liquid crystal may convert one polarization into another, because of its birefringence and thus degrades the performance of the switch. Good contrast ratios can be achieved by using alignment layers with weak anchoring strengths and appropriate thin cell gaps.

In this study the μ-rubbing technique is used to micro-pattern polyimide alignment layers using a metallic sphere at different loads. Optical and atomic force microscopy shows that the width of the patterns ranges from 12-40 μm and depth ranges from 2-14 nm. Our primary finding is that μ-rubbing induces planar alignment in polyimides. We performed μ-rubbing on pre-rubbed polyimide perpendicular to the rubbing direction. It is found that μ-rubbing erases the alignment properties of the pre-rubbing procedure. Liquid crystal cells were constructed using the pre-rubbed polyimide substrates with μ-rubbed patterns on one side and a homogeneously rubbed polyimide layer on the other side. Therefore the pre-rubbed polyimide layers are crossed and consequently a twisted nematic alignment is observed outside the micro-patterns. Within the micro-patterns, the directions of the pre-rubbing and μ-rubbing are parallel, a planar alignment observed. In another configuration, liquid crystal cells were made with pre-rubbed polyimide substrates having micro-patterns on both sides to give grid pattern with planar and twisted nematic configuration. Studies were extended to determine the pretilt of the micro patterned area.

While it is well known that it is possible to determine the effective flexoelectric coefficient of nematic liquid crystals using hybrid cells, this technique can be difficult due to the necessity of using a D.C. field. We have used a second method, requiring an A.C. field, to determine this parameter and here we compare the two techniques. The A.C. method employs the linear flexoelectrically induced linear electro-optic switching mechanism observed in chiral nematics. In order to use this second technique a chiral nematic phase is induced in an achiral nematic by the addition of a small amount of chiral additive (~3% concentration w/w) to give helix pitch lengths of typically 0.5-1.0 μm. We note that the two methods can be used interchangeably, since they produce similar results, and we conclude with a discussion of their relative merits.

Two different configurations of transflective liquid crystal displays (LCDs) using multi-domain method will be presented. One is composed of hybrid-aligned nematic mode in the reflective region and parallel-rubbed vertically aligned mode in the transmissive region. In order to make the reflective and transmissive regions in the same pixel independent, an Ar⁺ ion-beam alignment method is used. The other multi-domain transflective LCD, where vertically aligned mode is applied, has patterned metal electrodes on one substrate. In this mode, the device can be designed with single driving circuit and single cell gap. These transflective LCDs show excellent performance in reflectance and transmittance characteristics, viewing angle property, and contrast ratio.

We have been developing a novel-structure ferroelectric liquid crystal (FLC) device containing micropolymers for roll-up screen displays. We studied bending-iteration tolerance of a flexible FLC device containing polymer-fiber networks and lattice-shaped walls. Although conventional bistable FLC devices have the disadvantage of fragile smectic layer structures, the polymer walls fasten two flexible thin plastic substrates and keep the FLC layer thickness constant even when the device is bent. Otherwise, the anchoring of the molecular-aligned polymer networks enables FLC to obtain monostable molecular switching. We first examined mechanical stability of smectic layers in monostable FLC devices by shearing two substrates. It was found that the monostable FLC device shows good tolerance without generating alignment defects, in comparison with the bistable FLC device. We then formed a flexible device of a size of 100mm x 100mm by utilizing two-step photopolymerization-induced phase separation of an FLC/monomer solution film coated by a flexographic printing method. As a result, the 2-μm-thick cured composite film supported the two 100-μm-thick plastic substrates. We repeatedly bended it at a minimum curvature radius of 20mm in period time of 20s. As a result, its microscopic texture and electrooptic effect were not changed even after bending of 1000 times. The spatial uniformity of the flexible device was kept for more than 10000-times bending.

The lasing output characteristics of two different types of photonic band edge liquid crystal lasers have been investigated. The required helical structure or periodic change in the refractive index was realised by using either a chiral nematic or a chiral smectic C as the liquid crystal host. The fluorescent dye doped photonic band edge lasers exhibited very different emission characteristics. A Q-switched Nd:YAG pulsed laser, frequency doubled to 532nm with pulse lengths of 5ns was used to excite the samples. Typical laser parameters such as slope efficiency and input energy threshold values were examined for each laser and results indicated that the chiral smectic C laser was more efficient. We believe that the higher performance of the chiral smectic C laser is attributed to the increase in the degree of order of the host.

Ring light distribution patterns emerging after illumination of a material that forms a conic beam can be obtained in diverse cases. There are some phenomena that produce such distributions without an artificially tailored or designed mask. This device is produced by intermixing and curing of conventional PDLC form by the combination of optical glue and the nematic liquid crystal E7. When the device is illuminated with a He-Ne laser, a ring diffraction pattern with a spot in the center is observed. It was observed experimentally that the radius of the projected ring decreased when we applied an external voltage to the device with the indium tin oxide electrodes. The voltage dependent variation in the radii of the rings can be understood as a change in the period of the concentric spiral following the direction of the applied field when a voltage is applied in this device.

The LC anchoring energy is related to the interaction of the Liquid Crystal molecules and alignment layer. Therefore the anchoring property of the Liquid Crystal in a display device could be tuned by controlling this interaction. To decrease the anchoring strength of the Liquid Crystals at the surface layer in display device, several kinds of perfluorinated additive were added to the Commercial Nematic Liquid Crystal, E7. The overall electro-optical and physical properties were measured to determine the role of the additive in Liquid Crystal mixtures. The molecular structure of the additive was changed to impose different polarity and interaction with the Liquid Crystal and alignment layer. The additives affected the surface property and produced a slippery surface without any phase separation.

In this paper, we measure the emission energies of three different photonic band edge lasers containing nematic hosts which have slightly different physical properties. The low molar mass monomers used as nematic hosts are identical in terms of molecular shape except for the length of the terminal alkyl chain. The photonic band edge laser which contains an even number of methylene units in its alkyl chain is found to have the lowest lasing threshold at both the same absolute temperature and the same shifted temperature. At the same excitation energy the laser output for each sample is found to be proportional to the orientational order parameter of the nematic host. However, when plotted simultaneously the absolute value of the order parameter does not correlate with the same emission energies in each sample. As a result we consider other factors that maybe of equal importance to the operating efficiency of the PBE laser in order to obtain viable candidates that are able to explain the discrepancy in our results. Finally, we introduce a figure of merit parameter which contains the candidates most likely to affect the operating efficiency and obtain much better agreement with our results than with the orientational order parameter alone.

The visual displays of contemporary military flight simulators lack adequate definition to represent scenes in basic fast-jet fighter tasks. For example, air-to-air and air-to-ground targets are not projected with sufficient contrast and resolution for a pilot to perceive aspect, aspect rate and object detail at real world slant ranges. Simulator display geometries require the development of ultra-high resolution projectors with greater than 20 megapixel resolution at 60 Hz frame rate. A new micromirror device has been developed to address this requirement; it is able to modulate light intensity in an analog fashion with switching times shorter than 5 μs. When combined with a scanner, a laser and Schlieren optics, a linear array of these flexible micromirrors can display images composed of thousands of lines at a frame rate of 60 Hz. Recent results related to evaluation of this technology for high resolution projection are presented. Alternate operation modes for light modulation with flexible micromirrors are proposed. The related importance of controlling the residual micromirror curvature is discussed and results of experiments investigating the use of the deposition pressure to achieve such control are reported. Moreover, activities aiming at minimizing the micromirror response time and, so doing, maximizing the number of image columns per image frame are discussed. Finally, contrast measurement and estimate of the contrast limit achievable with the flexible micromirror technology are presented. All reported activities support the development of a fully addressable 2000-element micromirror array.

A novel rear projection screen (Blue Ocean screen, Nitto Jyushi Kogyo, Co., Ltd.) has been developed. Blue Ocean screen is a single polymer plate requiring no lens element. The projected image is formed on the screen surface by the multiple light scattering. An image light is multiply scattered and is converted into homogeneous light distribution efficiently due to the internal particles of micron order dispersed in the acrylic polymer matrix. An ambient light is reduced by the dye molecules doped in the polymer and the anti-reflective coating on the screen surface. The condition of the particles and the concentration of the dye molecules have been optimized by the ray tracing simulation program based on Mie scattering theory using a Monte Carlo method. The screen containing the particles of optimum condition exhibits the wide viewing angle, the well-controlled color balance, and the high sharpness level at the same time. The contrast level of the projected image in ambient light is improved by controlling the concentration of the dye molecules. This paper describes the optimization obtained theoretically and experimentally, and demonstrates the advantage of Blue Ocean screen.

With the advent of digital cinema, medical imaging, and other applications, the need to properly characterize projection display systems has become increasingly more crucial. Several standards organizations have developed or are presently developing measurement procedures (including ANSI, IEC, ISO, VESA, and SMPTE). The National Institute of Standards and Technology (NIST) has played an important role by evaluating standards and procedures, developing diagnostics, and providing technical and editorial input, especially where unbiased technical expertise is needed to establish credibility and to investigate measurement problems.

Temporal measures of display performance are important for depiction of still images, and are even more critical for depiction of moving images (video). In addition to the flicker and crawling patterns that occasionally appear when certain colors/grayscales and patterns are displayed (e.g. DMD/plasma temporal modulation), moving images are susceptible to a host of time-based artifacts (visible defects) such as motion blur, color breakup, image distortion, and incorrect depiction of object motion. Accuracy of temporal representation can be affected by temporal compression (e.g. motion prediction) in the image data handling, and by the operation of the display system (e.g. scaling algorithm). It is widely known that well-presented motion imagery can offer both improved quality and improved interpretability compared to comparable still imagery (for example a freeze frame of a video), provided that timing characteristics are accurately reproduced. Because of the importance of display characteristics, positional measurement of the physical light output of the display is a necessary addition to measurement of image component motion in the video data file. The NIST Motion Image Quality Project team is adapting its method of sequential image capture with external hardware timestamp (Electronic Imaging 2003), to make precision measurements of the temporal characteristics of displays. Hardware measurements are being combined with subjective evaluation of video content and image file analysis, to produce a new model for moving image quality and interpretability, which will serve as a guide both for content creation and for display design.

Multi-primary displays, which enable to expand their color gamut, have a degree of freedom in the selection of the device control signals to reproduce a set of tristimulus values. To reproduce a given tristimulus values on a multi-primary display, we need a color conversion algorithm which gives a unique set of device control signals; several algorithms with different characteristics have been proposed. However, they do not guarantee that control signals change smoothly even when tristimulus values change smoothly. Such signal discontinuity is pointed out as a cause of pseudo contour appeared in smooth tonal change when color matching functions of observers are deviated from the standard one or when device profiles include some error. In this article, first, the relation between signal discontinuity and pseudo contour is theoretically analyzed. Then a comparative evaluation is performed on the smoothness of the gradation patterns among three color conversion algorithms. As a result of the comparison, it was confirmed that a method that generates smooth signal all over the color gamut gave the smoothest gradation both objectively and subjectively.

We have ever reported a phosphor screen, which is a 5-in. poly-crystal MgAl₂O₄ phosphor screen. The 5-in. poly-crystal MgAl₂O₄ phosphor screen has a very good performance, such as high luminance, high resolution, cheap cost and easily obtained. Recently we develop a high performance 5-in. poly-crystal phosphor screen. We deposit a multi-layer interface filter on the poly-crystal MgAl₂O₄ substrate. The filter is a multi-layer alternate high and low index of refraction film which was fabricated by depositing high index of refraction of titanium oxide and low index of refraction of silicon oxide. The measurement results show that the filter not only increases the MgAl₂O₄ phosphor screen’s white-D luminance, but also improves its chromaticity. The 5-in.R.G. B poly-crystal phosphor screens with the filter have 60% more luminance than those of common R.G. B poly-crystal phosphor screens, and the area of their chromaticity is almost 10% larger than that of common poly-crystal phosphor screen. The 5-in.R.G. B poly-crystal phosphor screens with the filter realize the authentic high performance.

The paper presents a current development in the field of high-speed spatial light modulators. The Digital Micromirror Device (DMD) developed and produced by Texas Instruments Inc. (TI) stimulated new approaches in photonics. Recently, TI introduced the Discovery general purpose chipset to support new business areas in addition to the mainstream application of DMD technology in digital projection. ViALUX developed the ALP parallel interface controller board as a Discovery 1100 accessory for high speed micromirror operation. ALP (Accessory Light Modulator Package) has been designed for use in optical metrology but is widely open for numerous applications. It allows for rapid launch into new DMD applications and can be integrated instantly into existing systems or may initiate new developments. The paper describes both, the general hardware architecture and the software concept of the new high-speed controller solution. Binary and gray-value patterns of variable bit-depth can be pre-loaded to on-board SDRAM via USB and transferred to DMD at high speed (up to 6900 XGA frames per second). Three examples are to illustrate how the approach enables advanced applications of DMD technology in metrology, testing and beyond.

Projection engine designs are mostly based on discrete optical components including color filters, mirrors, relay lenses, prisms, etc., which tends to be expensive and increase the space requirement. With the advancement of light pipe based illumination system, e.g. the Wavien patented dual paraboloid reflector system, and light-pipe based polarization recovery system, it would be advantage to design a light-pipe based projection engine for a complete light-pipe based system for low cost and space saving applications. In this paper, a totally light-pipe based projection engine is described. It consists of an etendue efficiency illumination system using the dual paraboloid reflector system with a lensed tapered light pipe as the output. The output is then directed into a light-pipe based polarization recovery system such that the output is polarized. The polarized light is then separated into its individual RGB colors, and is directed into the corresponding HTPS imager chips separately by the use of light pipes, prism, and beam splitters. The outputs from the imager chips are then recombined by an X-cube and projected onto the screen. This light-pipe based system uses low cost optical components and take up much less space than the traditional projection system.

The past decade has seen a rapid development of projection systems. Projectors as small as only a few liters in size deliver several thousand screen lumens and are, with an efficacy of over 10 lm/W, the most efficient display systems realized today. This has been made possible by breakthroughs in lamp technology, particularly by the development of the UHP-lamp. This broadband light source with its outstanding brightness and lifetimes of over 10000 hours is ideal for projection applications. In this paper we want to describe three major technological trend lines in the development of UHP-lamps over the past decade: First, there is a trend towards brighter projectors, which is fostered by a brightness increase of the UHP-lamps. At the same time, projectors have seen a dramatic reduction in size, which has been made possible mostly by reducing lamp- and driver-size by even a factor of 10. This was only possible by the development of new ignition concepts as well as new optical designs of the reflector. And finally, UHP-lamps have seen quite some improvement in color rendering by using even higher pressures and shorter arc gaps. This allows for more colorful pictures and even more efficient projector designs.

A dual paraboloid reflector system conserves the source brightness by producing a real image of the arc on the target space. Traditional elliptical and parabolic reflector tends to degrade the brightness of the arc due to the angular dependence of the magnification such that the image at the target space is the superposition of multiple images of the arc with varying degree of magnifications. In this paper, we present steps for optimizing a projection illumination system consisting of the dual paraboloid reflectors. The effects of various parameters including reflector sizes, scattering and angular extents were evaluated using ray-tracing model. The results of the calculations are compared with experimental measurement.

New designs are presented of backlight systems for transmissive and transflective LCD’s based on stretched PET films with a well-defined micro-structure, which emit highly collimated or diffuse and linearly polarized light with a high efficiency. Moreover, edge-lit waveguide systems are discussed equipped slanted phase gratings which combine a range of desirable features such as a high transparency in direct view, a direct emission of light at normal angles to the plane of the waveguide and a purely unidirectional out-coupling of light towards the LCD-side. Moreover, these illumination systems emit colored, linearly polarized light which should contribute significantly to the energy efficiency of transmissive, transflective and reflective LCD displays.