This PDF file contains the front matter associated with SPIE Proceedings Volume 8280, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

A new compact green laser is demonstrated by using a mGreen module based on compact packaged MgO doped periodically poled lithium niobate (MgO:PPLN). The green laser can generate over 700-mW green light with an opticalto- optical efficiency of 29.6% and a volume of less than 7 cm³. The excellent performances of the MgO:PPLN based lasers, including high efficiency, compact size, low cost and being suitable to mass production, are very attractive for laser display applications.

Laser displays require red, green and blue (RGB) laser sources each with a low-cost, a high wall-plug efficiency, and a small size. However, semiconductor chips that directly emit green light with sufficient power and efficiency are not currently available on the market. A practical solution to the "green" bottleneck is to employ diode pumped solid state laser (DPSSL) technology, in which a frequency doubling crystal is used. In this paper, recent progress of MgO doped periodically poled lithium niobate (MgO:PPLN) frequency doubling optical chips will be presented. It is shown that MgO:PPLN can satisfy all of the requirements for laser displays and is ready for mass production.

We present two LCD modes enabling short rise and fall switching time, being in the microsecond range in most of the modes. Polymeric network, created in the liquid crystal bulk, as well as in the presence of flexoelectric polarization are among those employed for achieving of fast switching modes in LCDs. Proper assembling and electronic driving of two parallel liquid crystal cells, arranged in a double cell configuration, is another approach enabling a fast switching mode between bright and dark state of the device. We discuss these modes in terms of device performance and their suitability for application in LCDs.

We studied two types of bistable liquid crystal devices that can be operated in the memory mode as well as in the dynamic mode. One of them is a pixel-isolated twist-splay nematic LC cell that has two stable states of π- twist and splay. Polymer walls are formed at pixel boundaries by anisotropic phase separation between nematic liquid crystals and reactive mesogens. Operation in the memory mode can be achieved through bistable switching between the splay and π-twisted states. The other one is a bistable twisted-nematic mode that has two stable states of -π/2 and +π/2 twist. Three-terminal electrodes are used to apply both vertical and in-plane electric field to both devices. The proposed bistable modes has an infinite memory time and the fast transition time compared to other bistable liquid crystal modes.

We present a fast-switching, contrast-enhanced liquid crystal polarization modulator suitable for use as a polarization switch in time-multiplexed stereoscopic 3D applications. By utilizing a double-cell structure together with a dedicated driving scheme and an external quarter-wave retarder we can achieve fast, powered switching between two orthogonally polarized output states with completely symmetric operation between left and right eye images, including high extinction at all wavelengths for the dark states. The polarization modulator is especially attractive for the use in combination with high-end DLP®-based, single-lens stereoscopic 3D projectors operating at high frame rates, and enables high-brightness, low-ghosting viewing using lightweight and comfortable circular polarized passive 3D glasses. The practical advantages of a fast 50μs polarization modulator are discussed.

All 3D displays have the same intrinsic method to induce depth perception. They provide different images in the left and right eye of the observer to obtain the stereoscopic effect. The three most common solutions already available on the market are active glass, passive glass and auto-stereoscopic 3D displays. The three types of displays are based on different physical principle (polarization, time selection or spatial emission) and consequently require different measurement instruments and techniques. In the proposed paper, we present some of these solutions and the technical characteristics that can be obtained to compare the displays. We show in particular that local and global measurements can be made in the three cases to access to different characteristics. We also discuss the new technologies currently under development and their needs in terms of optical characterization.

We propose three-dimensional floating display which uses a concave cylindrical mirror (CCM), wedge prisms, and a digital micro-mirror device (DMD). Wedge prisms can make the direction of projected images tilt by a specific angle from the incident direction. In our system, wedge prisms are rotated to project images to whole direction of the cylindrical mirror. Projected images from the DMD projector are reflected and distorted by the CCM simultaneously. We generate inversely distorted images to correct the image distortions to display original images. As the wedge prisms rotate, the tilt angle in the longitudinal plane of the CCM rotates. This means that images from the DMD can be projected in any horizontal direction. Viewers can see 3D objects with horizontal parallax in any horizontal direction. The further explanation of the proposed system is provided, and the experimental results are also presented.

If the arc lamp in standard display projectors is replaced by lasers, the projector can gain several advantages such as improved color gamut, higher contrast and brightness. Coherent by nature, the laser also adds one significant disadvantage to the projector: the presence of speckle, which manifests itself as noise-like intensity fluctuations over the image. In this paper, we present an overview of our work concerning correlated speckle patterns. We give general formulas for the speckle contrast of the sum of N partially correlated speckle patterns. It is shown how the speckle contrast depends on the correlations between the individual speckle patterns, and for the case of a fully developed speckle pattern we present a general expression for the correlations. As an example, we look at speckle suppression by discrete rotation of a diffraction pattern on a diffuser. We use a sinusoidal phase grating which has the advantage that the zeroth order can be extinguished without loss of power. Hence, no part of the diffraction pattern remains stationary when rotated. Expressions for correlations are found, with different degrees of generality, which enable us to find expressions for the contrast. Furthermore, the influence of the diffraction pattern's complex amplitude distribution on the correlation and speckle contrast is investigated.

Flying-spot display applications require high luminance (> 100 TCd/m²) red-emitting lasers. High luminance is defined as a high optical output power and a nearly diffraction limited beam quality at a wavelength with a good visibility of the human eye. Diode lasers, with all their beneficial properties such as direct modulation capability, small size and good electro-optical efficiency, are so far unable to achieve such high luminance, due to catastrophic optical mirror damage (COMD) caused by high facet loads. (See manuscript for full abstract.)

Advancements in laser diode technology have lead to the utilization of lasers in pico-projector systems. These proposed devices would need to take full advantage of the coherent source, while still providing full RGB color. Previous work has been completed analyzing 532 nm green diodes in conjunction with hadamard-matrix diffusers for reducing the disruptive speckle noise caused by coherent sources. In addition to the speckle, many small form factor laser diodes have aspheric or nonsymmetric beam shapes upon excitation. Non-circular beam shapes are difficult, if not impossible, to collimate properly. Collimation and beam symmetry is vital in order to keep the bulk of the sources power in the lower order diffractive modes that form from beam shaping optics such as diffusers and micro-lens arrays. Because of these requirements and unique diode structure, generic spherical lenses will not suffice, leading to new techniques for beam collimation. This paper looks at creating the proper beam shape through the use of multimode fiber optics. The output wave from the fiber is then passed through a diffuser. Speckle contrast measurements will be analyzed for both rotating and stationary instances of the diffuser. In addition, other techniques for creating more functional beam shapes will be evaluated in comparison with a fiber optic setup.

Blue phases are types of liquid crystal phase which can appear in a narrow temperature range between a chiral nematic phase and isotropic liquid phase. Blue Phase (BP) liquid crystals have been known to exist in a small temperature range. Recently, broadening the temperature range of a BP liquid crystal has occurred by using a mixture of nematic bimesogenic liquid crystals or by polymerizing a small amount of monomer in a BP to stabilize the cubic lattice against temperature variation. In this study, we report a low switching voltage polymer stabilized blue phase (PSBP) liquid crystal device. We showed the stabilization of blue phases over a temperature range of 30.4 °C including room temperature. We observed the temperature independent of Bragg wavelength. Furthermore, the polymer effect on the electo-optic properties of a self assembled nanostructured blue phase liquid crystal composites have been investigated. As well as the ratio between two monomers, the overall monomers concentration is controlled.

In this paper, we propose new pixel structures for high transmittance in the patterned vertical alignment mode. We formed the protrusion or the slit on the top substrate to reduce the width of disclination lines at the domain boundaries.

The major efficiency loss in current liquid crystal displays(LCD) are the absorption in polarizers and color filter, and both can be resolved with decent backlight design which takes light polarization and color separation into consideration. Those improvement schemes on the backlight normally will not trade off the image quality readily achieved in the commercial LCD. Both polarization and color separation schemes for the backlight are reviewed with categorization on the basic concept, followed by the proposal of possible combinations for both direct lit and edge lit configuration with the consideration on the availability of associated components. Two total solutions, including polarization conversion module for LED and pixelized backlight with RGB LED for direct lit and edge lit respectively, are given with demonstration of preliminary result achieved so far as the efficiency improvement schemes for LCD backlight.

The proposed paper relates to holographic optical elements that are used for recording micro holograms with usage of laser source of coherent radiation. Such devices for micro holograms recording are used for recording of information presented in digital view into light sensitive materials for future storage and reconstruction of recorded information. Important characteristic of recording devices is the overall active volume of device optical part. The challenging task is to provide considerably less volume of recording device optical part at the cost of using integrated optical elements. Almost all existing solutions have a big quantity of different optical elements divided by air spacers. The relative positions of all these elements affects on working efficiency of whole device. We propose a scheme providing fundamental improvements of the basic scheme in parts of overall device sizes, quantity of elements, and combined functionality of each element. The main advantages of proposed solution are as follows: First, this solution utilizes various integral optical elements, where each element is a united not adjustable optical element, replacing separate and adjustable optical elements with various forms and configurations. Second, geometrical form of integral elements provides small sizes of whole device. Third, geometrical form of integral elements allows creating a flat device. And finally, absence of adjustable elements provides rigidity of the whole devices. The usage of integrated optical means based on waveguide holographic elements allows creating a new type of compact and high functional display devices for various applications like mobile and consumer usage.

Light-emitting displays with colloidal quantum-dot (QD) have recently received considerable attention due to advantages of QD property such as high quantum yields, extremely narrow emission, spectral tunability, and a higher stability than other existing luminophores. However, the difficulty of patterning red, green, and blue (RGB) pixels of three individual QDs with controlled interfaces has prevented from developing a full-color QD display with acceptable quantum efficiency. In this talk, the issues of QD EL and successful embodiment of full-color QD display by the solvent-free transfer printing of QD pattern will be presented. Modulated QD assemblies exhibit the excellent morphology, wellordered QD structure, and clearly defined interfaces, which result in significant enhancements in the charge transport/balance in the QD layer. A large-area full-color QD displays on a glass substrate, and even on a flexible substrate can be realized in this manner with the control of nano-interfaces and carrier behaviors.

Unprotected electronic components exposed to moisture from high humidity may fail due to corrosion of metal leads or other unfavorable reactions on chemically sensitive components. This is of high interest for silicones that encapsulate Light Emitting Diodes (LEDs) dies. For these applications, moisture and oxygen may react with materials, such as phosphor, used to make white LEDs for back-lighting applications and decrease or change the light output and color over time. Of the polymeric adhesives and sealants commercially available, silicones are used for their thermal stability, clarity, and comparably low modulus that provides stress relief during thermal cycling. In addition, silicones are also known to be very permeable to low molecular weight gases such as water vapor and oxygen. Recently, several types of silicones were tested for the oxygen and water vapor transmission rates, and it was found that they can have drastically different results. Silicone properties strongly affecting permeability are polymer backbone chemistry, crosslink density and fillers. Phenyl (C₆H₅) and trifluoropropyl (CF₃CH₂) groups are used to optimize the refractive index of optically clear silicones. The effect of chemical composition on the water vapor transfer rate (WVTR) and the oxygen transfer rate (OTR) at 40⁰ C and 90% Relative Humidity was investigated on several silicones with various refractive indices and compared to polydimethylsiloxane (PDMS) with similar durometers. It was found that polymer backbone chemistry had a significant influence on the permeation rates and will assist in material selection when designing for low-permeable barriers to improve package reliability.

An electrically-tunable optical zoom system using liquid crystal (LC) lenses is demonstrated. The mechanism of the optical zoom system is to use two lenses and a camera system to achieve focusing and zooming function. In this paper, we analyzed the imaging conditions and the magnification of the optical zoom system. The relation between the focusing properties of LC lenses and zoom ratio of the optical zoom system is also discussed. The electrically-tunable optical zoom system using two LC lenses has high zoom ratio (~7.9:1 to ~5.5:1), short system length (<10 cm) and the object can be zoomed in or zoomed out continuously at the objective distance of infinity to 10 cm. The potential applications are cell phones, cameras, telescopes and pico projectors.

A thin porous layer of bonded ceramic microparticles has been developed to provide structural integrity and a stationary matrix for use in reflective-mode reverse-emulsion electrophoretic displays (REED), based on self-assembled nanodroplets dispersed in a non-polar liquid. REED ink uses low-cost materials and manufacturing processes, yet is capable of video speed and low voltage operation below 10 V. Porous layers of titanium dioxide (TiO₂) are prepared as thin as 10 microns by fluidizing the particles in a water-based slurry with polymeric adhesive. The slurry is distributed between glass shear plates, one of which serves as the substrate for the working device. Particle morphology is examined using scanning electron microscopy and layer uniformity is characterized by opacity measurements using a throughbeam fiber optic sensor. Performance of the bonded matrix with REED ink is compared to baseline performance of a paste mixture, comprised of the same ink and unbonded TiO₂ particles. Results show that at 25% volume fraction, the bonded substrate improves image bistability and is better able to maintain both light and dark intensity after extensive switching. The same bonded substrate also improves image bistability when power is disconnected, even compared to a paste with 40% volume fraction of TiO₂.

A very simple scheme of holographic projection is presented with some experimental results showing good quality image projection without any imaging lens. This technique can be regarded as an alternative to classic projection methods. It is based on the reconstruction real images from three phase iterated Fourier holograms. The illumination is performed with three laser beams of primary colors. A divergent wavefront geometry is used to achieve an increased throw angle of the projection, compared to plane wave illumination. Light fibers are used as light guidance in order to keep the setup as simple as possible and to provide point-like sources of high quality divergent wave-fronts at optimized position against the light modulator. Absorbing spectral filters are implemented to multiplex three holograms on a single phase-only spatial light modulator. Hence color mixing occurs without any time-division methods, which cause rainbow effects and color flicker. The zero diffractive order with divergent illumination is practically invisible and speckle field is effectively suppressed with phase optimization and time averaging techniques. The main advantages of the proposed concept are: a very simple and highly miniaturizable configuration; lack of lens; a single LCoS (Liquid Crystal on Silicon) modulator; a strong resistance to imperfections and obstructions of the spatial light modulator like dead pixels, dust, mud, fingerprints etc.; simple calculations based on Fast Fourier Transform (FFT) easily processed in real time mode with GPU (Graphic Programming).

We consider applications of wave-guiding technologies for flexible displays. First, a flexible backlight can be constructed by guiding laser light through an optical fiber arranged in a spiral manner. The light leaks out via the grooves fabricated on the optical fiber. For uniform illumination, the probability of light extraction at each groove and the pitch of the grooves are adjusted. Second, a polymer waveguide with successive branches distributes the optical power from a laser to two-dimensional emission points on a plane. The division ratio at each branch is an important design parameter for uniform light output. At each branch and emission point, a mirror is placed for 90-degree optical path redirection. This constitutes a flexible backlight. Third, in a more technically demanding design, a mirror based on the micro-electro-mechanical systems technology scans a laser beam on the entrance surface of the waveguide and each emission point is addressed sequentially. An image can be displayed by intensity modulation of the laser light synchronized to this scanning action. The precision of the waveguide fabrication and the beam scanning accuracy would determine the display resolution. Finally, such a waveguide may be applied for concentrated photovoltaic applications. An array of lenses is stacked on the waveguide so that the optical power is focused on each mirror. The direction of the light propagation is reversed. Now the exit surface of the waveguide is coupled to solar cells. In all these cases, the polymer waveguide technology offers a cost advantage due to its feasibility for the roll-to-roll process.