Showing papers in "IEEE\/OSA Journal of Display Technology in 2010"

State of the Art in Holographic Displays: A Survey

Abstract: True-3D imaging and display systems are based on physical duplication of light distribution. Holography is a true-3D technique. There are significant developments in electro-holographic displays in recent years. Liquid crystal, liquid crystal on silicon, optically addressed, mirror-based, holographic polymer-dispersed, and acousto-optic devices are used as holographic displays. There are complete electro-holographic display systems and some of them are already commercialized.

Submillisecond Gray-Level Response Time of a Polymer-Stabilized Blue-Phase Liquid Crystal

Abstract: The gray-to-gray response time of a polymer-stabilized blue-phase liquid crystal is investigated. As the voltage increases, rise time decreases gradually but decay time remains unchanged. A set of analytical equations is used to fit the measured results, and an acceptable agreement is obtained.

Compressive Fresnel Holography

Abstract: Compressive sensing is a relatively new measurement paradigm which seeks to capture the “essential” aspects of a high-dimensional object using as few measurements as possible. In this work we demonstrate successful application of compressive sensing framework to digital Fresnel holography. It is shown that when applying compressive sensing approach to Fresnel fields a special sampling scheme should be adopted for improved results.

Hysteresis Effects in Blue-Phase Liquid Crystals

Abstract: Hysteresis effects of two blue-phase (BP) liquid crystals BP-I and BP-II, and polymer-stabilized BP-I and BP-II are investigated. BP-I exhibits a relatively slow response time and a large hysteresis. After polymer stabilization, its operating voltage is increased slightly, but its response time is dramatically reduced and hysteresis narrowed. In contrast, BP-II exhibits almost no hysteresis and submillisecond response time, but after polymer stabilization its hysteresis is amplified.

A Direct-Write Printed Antenna on Paper-Based Organic Substrate for Flexible Displays and WLAN Applications

Abstract: This paper presents the design, fabrication and measurements of a direct-write printed low-cost and flexible inverted-F antenna on an ultra-low-cost paper-based organic substrate for wireless local area network (WLAN) and flexible display applications. Innovations include the study and utilization of paper as a high-frequency substrate for the first time in the gigahertz (GHz) range, the fabrication technology for the direct-write printing of the antenna as a flexible RF electronic device, and the investigation of antenna flexibility in conjunction with flexible displays. Although paper substrates exhibit relatively high dielectric losses (tanδ ~ 0.065 at 2.45 GHz), the maximum realized gain of the fabricated antenna is measured to be + 1.2 dBi giving a total efficiency ~ 82%. Simulated results of the antenna's return loss and radiation patterns agree well with the measurements, and can lead to a whole new class of flexible low-cost electronic devices of the future.

Integral Three-Dimensional Television Using a 33-Megapixel Imaging System

Abstract: We have developed integral three-dimensional (3D) television using an ultra high definition imaging system. The system uses a device having 7680 pixels in the horizontal direction and 4320 pixels in the vertical direction for each of the red, green, and blue channels. A lens array comprising 400 lenses is configured in the horizontal direction and one comprising 250 lenses is configured in the vertical direction. The system is designed to ensure a maximum spatial frequency of 11.3 cycles/degree and a viewing angle of 24 degrees when the display is observed from three times the display height. The setup described here has simultaneously maintained the balance between the maximum spatial frequency and the viewing angle by shortening the focal length of the elemental lens while narrowing the pitch of the elemental lens. We have confirmed the generation of 3D images with an appearance that varies in a natural manner according to the position of the observer.

Inkjet Printed RGB Quantum Dot-Hybrid LED

Abstract: We report DC driven full color inkjet printed quantum-dots light-emitting devices. The inkjet was used to print monochromatic red, green, and blue, as well as integrate red-green-blue light-emitting quantum dots unto a substrate having QVGA display. The performance of the inkjet printed monochrome devices was on the same order as that of spin coated ones. For the full color RGB devices, a video brightness of 100 cd/m2 is achieved at 9.3 V.

Recent Developments in 3-D Imaging Technologies

Abstract: Three-dimensional (3D) imaging technologies that have been developed recently are reviewed. In recent years, many new progresses in the 3D imaging have been made but most of them provide more practical solutions to comply with the commercialization efforts of the 3D imaging. Based on time-multiplexing, revisiting the stereoscopic imaging methods is one of the solutions to make possible each view image has the full panel resolution. The rapid progresses of high speed LCDs and the initiation of stereoscopic imaging service to mobile phones have made the method possible. The efforts also encouraged more concerns in evaluating 3-D image quality and identifying factors affecting the quality. In this respect, in-depth analysis has been done for the multiview imaging methods, and other forms of multiview 3D image display methods, such as the focused image/pixel array of multiview images are also analyzed.

Low Voltage Blue-Phase LCDs With Double-Penetrating Fringe Fields

Abstract: A blue-phase liquid crystal display (BP-LCD) with an in-plane switching (IPS) electrode and etched substrate for generating double-penetrating fringe fields is proposed. An etching depth of 1-2 helps to lower the operating voltage by 30%. This etched IPS BP-LCD also exhibits a wider viewing angle than the conventional one because of the created multi-domain structures in the etched areas. Physical mechanisms responsible for the observed phenomena are discussed.

Real-Time Digital Holographic Microscopy for Phase Contrast 3D Imaging of Dynamic Phenomena

Abstract: Digital holography is a very effective tool for three- dimensional imaging of objects, since it yields the phase information directly without the need for additional optics. Another advantage is that of numerical focusing, allowing one to focus on to any desired plane. It has been used for microscopy with high effectiveness. One of the important features of digital holographic microscopy (DHM) is that it can be used for phase contrast imaging of otherwise transparent objects. This aspect of DHM is utilized here to study the dynamics of phase objects. Angular spectrum propagation (ASP) approach to scalar diffraction theory is used for numerical reconstruction of holograms.

Three-Dimensional Visualization of Objects in Turbid Water Using Integral Imaging

Abstract: In this paper, we demonstrate three-dimensional (3D) visualization of objects in turbid water. The sensing is performed by integral imaging. Multi-perspectives images are degraded due to light scattering and are treated by statistical image processing and computational 3D reconstruction algorithms to remedy the effects of scattering and to visualize the 3D scene. Reconstruction distances and underwater elemental images are calculated according to Snell's law. To the best of our knowledge, this is the first report on 3D reconstruction of objects in turbid water using integral imaging. Experimental results are presented.

Liquid Crystal Active Glasses for 3D Cinema

Abstract: Liquid crystals have been extensively studied and are massively used in display technology. Their recent use to provide optical shutters in active glasses for 3D cinema has focused the attention on new specific requirements. Recent improvements in the quality of 3D movies production and projection (e.g., involving triple flash projectors) resulted in the need for high quality glasses with no ghosting, no color banding, large viewing angle and good residual light. We present here the main relevant parameters to assess the quality required today by the studios and we compare the main liquid crystal options which can be used with their respective advantages.

Highly Flexible AM-OLED Display With Integrated Gate Driver Using Amorphous Silicon TFT on Ultrathin Metal Foil

Abstract: This paper introduces the technology behind developing of flexible AM-OLED displays with improved color and reduced bending radius. Developing a-Si TFT fabrication technology using 80-μm ultrathin stainless steel foil as the substrate and integrating driver electronic in the display panel, we were able to demonstrate a full-color AM-OLED displayed in a curvature of less than 5 cm bending radius. Total panel thickness of 0.30 mm, brightness of 100 cd/m2 and color reproducibility of 63% were achieved.

3D Holographic Imaging and Trapping for Non-Invasive Cell Identification and Tracking

Abstract: Real-time high-throughput identification, screening, characterization, and processing of biological specimen is of great interest to a host of areas spanning from cell biology and medicine to security and defense. Much like human biometrics, microorganisms exhibit natural signatures that can be used for identification. In this paper, we first overview two optical techniques, namely digital holographic microscopy and holographic optical tweezers which can non-invasively image, manipulate, and identify microorganisms in three dimensions. The two methods bear similarities in their optics and implementation. Thus, we have proposed a new approach to identification of micro/nano organisms and cells by combining the two methods of digital holographic microscopy and holographic optical tweezers which can be integrated into a single compact hardware. The proposed system can simultaneously sense, control, identify, and track cells and microorganisms in three dimensions. New possibilities that arise from the proposed method are discussed.

Digital Holography at Shot Noise Level

Abstract: By a proper arrangement of a digital holography setup, that combines off-axis geometry with phase-shifting recording conditions, it is possible to reach the theoretical shot noise limit, in real-time experiments. We studied this limit, and we show that it corresponds to 1 photo-electron per pixel within the whole frame sequence that is used to reconstruct the holographic image. We also show that Monte Carlo noise synthesis onto holograms measured at high illumination levels enables accurate representation of the experimental holograms measured at very weak illumination levels. An experimental validation of these results is done.

Self-Rechargeable Paper Thin-Film Batteries: Performance and Applications

Abstract: This paper reports on the use of cellulose paper simultaneously as electrolyte, separation of electrodes, and physical support of a rechargeable battery. The deposition on both faces of a paper sheet of metal or metal oxides thin layers with different electrochemical potentials, respectively as anode and cathode, such as Cu and Al, lead to an output voltage of 0.70 V and a current density that varies between 150 nA/cm2 and 0.5 mA/cm2, subject to the paper composition, thickness and the degree of OHx species adsorbed in the paper matrix. The electrical output of the paper battery is independent of the electrodes thickness but strongly depends on the atmospheric relative humidity (RH), with a current density enhancement by more than 3 orders of magnitude when RH changes from 60% to 85%. Besides flexibility, low cost, low material consumption, environmental friendly, the power output of paper batteries can be adapted to the desired voltage-current needed, by proper integration. A 3-V prototype was fabricated to control the ON/OFF state of a paper transistor.

Color Breakup Suppression in Field-Sequential Five-Primary-Color LCDs

Abstract: Field-sequential-color liquid crystal displays (FSC LCDs) exhibit a ~ 3× higher optical efficiency and 3× higher resolution, but the color breakup (CBU) degrades the image quality and limits the practical applications. In this paper, we propose a method to reduce CBU by using five-primary LEDs instead of three. Without increasing the sub-frame rate as three-primary LCDs, we can suppress the CBU by utilizing proper color sequence and weighting ratios. The color gamut achieves 140% NTSC and the white brightness increases by more than 13%, as compared to the three-primary LCDs.

Enhancing the Brightness of Parallax Barrier Based 3D Flat Panel Mobile Displays Without Compromising Power Consumption

Abstract: This paper presents an alternative approach for achieving higher optical efficiency in conventional parallax barrier 3D mobile displays. The method entails modifying and enhancing the protrusion structure of conventional multi-domain vertical alignment (MVA) pixel arrays plus the storage capacitors (Cst) of the pixel circuitry which increase effective pixel transmission area by a factor of 1.07. Hiding the modified storage capacitor under the parallax barrier strip increases the barrier gap or slit size by a factor of 1.52. The result is a structure that enhances mobile displays' optical efficiency by a compounded factor slightly over 60% without compromising power consumption.

Specification of the Geometric Regularity Model for Fuzzy If-Then Rule-Based Deinterlacing

Abstract: A fuzzy if-then rule-based intra-field deinterlacing method using geometric duality is presented in this paper. The proposed method is a content-based hybrid scheme switching between the well-known edge-based linear average method and the proposed geometric duality-based deinterlacing method. Conventional deinterlacing methods usually employ edge-based interpolation techniques within pixel-based estimations. However, they are somewhat sensitive to noise and intensity variations in the image. Moreover, their performance is visually unacceptable due to their failure to estimate edge direction. To reduce this sensitivity, the proposed algorithm investigates features from low-resolution images, and applies them to high-resolution images to calculate the missing pixels. We analyzed properties of the missing pixels and modeled them using geometric regularity. Depending on the features of the region, the missing pixels were interpolated in different ways. The proposed algorithm is computationally feasible and promises to be a good candidate for a low-cost hardware interpolator.

Color Breakup Reduction by 180 Hz Stencil-FSC Method in Large-Sized Color Filter-Less LCDs

Abstract: Field-sequential color (FSC) is a high optical throughput technique for future green liquid crystal displays (LCDs). However, the FSC-LCD faces a lethal issue, color breakup (CBU) which degrades image clarity and prevents high level LCD-TV productions. We proposed the "180 Hz Stencil Field-Sequential-Color" method to redistribute intensities of the three primary color field-images to suppress CBU. By applying local color-backlight-dimming technology to FSC-LCDs, a low resolution colorful backlight panel combined with a high resolution color filter-less LC panel generated a "green-based multi-color" field-image which showed the most image luminance in the first field. Therefore, residual red and blue field-image intensities were reduced and effectively suppressed CBU when compared to field-rate increasing methods. In addition, to further implement hardware, the number of backlight divisions of 32×24 and a proper Gaussian point spread function profile were optimized via simulations while considering CBU reduction and image fidelity. Using optimized hardware parameters, the CBU phenomenon was suppressed by 50% of traditional RGB driving in simulation and was demonstrated on a 120 Hz 46-inch MVA LCD-TV.

Submicron Magneto-Optical Spatial Light Modulation Device for Holographic Displays Driven by Spin-Polarized Electrons

Abstract: We have proposed a spin transfer switching (STS MO-SLM) device, based on Magneto-optical (MO) spatial light-modulation and driven by spin-polarized current flow, and confirmed its basic operation and characteristics experimentally. The proposed SLM device can be operated without active-matrix devices, has a spatial resolution as small as several hundred nanometers and possesses the potential for being driven at ultra-high speed of several tens of nanoseconds. Unlike existing SLM devices, this device satisfies both the size and speed requirements of SLMs for use in displaying holographic three-dimensional (3D) moving images. To improve the light modulation characteristics of SLM device, we carried out studies on magnetic films with perpendicular magnetic anisotropy to obtain large magneto-optical signals, which enabled us to realize enhanced light modulation performance. In addition, we measured a MO signal that was about twenty-times larger than that possible with in-plane anisotropy. We conclude that the MO-SLM device that we are developing is suitable for displaying future super-high definition, holographic three-dimensional moving images.

Laser-Based Head-Tracked 3D Display Research

Abstract: The construction and operation of two laser-based glasses-free 3D (autostereoscopic) displays that have been carried out within the European Union-funded projects MUTED and HELIUM3D is described in this paper. Both use a multi-user head tracker to direct regions viewer's referred to as exit pupils to viewer's eyes. MUTED employs a direct-view LCD whose backlight comprises novel steering optics and in HELIUM3D image information is supplied by a horizontally-scanned fast light valve whose output is controlled by a spatial light modulator (SLM). The principle of operation, construction and results obtained are described.

Zigzag Electrodes for Suppressing the Color Shift of Kerr Effect-Based Liquid Crystal Displays

Abstract: The electro-optic properties of Kerr effect based liquid crystal display (LCD) with zigzag electrode structure are studied using a three-dimensional simulator. The optimal bending angle of the zigzag in-plane switching (IPS) electrodes is found to be 90° , which is different from the conventional strip electrodes. Although the zigzag structure exhibits a slightly lower transmittance than the strip IPS electrodes, it significantly suppresses the color shift while providing a relatively wide viewing angle.

Practical Evaluation of Illumination Watermarking Technique Using Orthogonal Transforms

Abstract: We have proposed an “Illumination Watermarking” technology with which the images of objects without copyright protection can contain invisible digital watermarking. This technology uses spatially modulated illumination possibly using an orthogonal transform, such as discrete cosine transform (DCT), as the method of embedding watermarks, and it can be applied to objects that do not have electronically embedded watermarking such as pictures painted by artists. We conducted a new series of experiments where one-bit binary data were embedded in one block that consisted of 8 × 8 pixels using the phase of the highest frequency component generated by a Walsh-Hadamard transform (WHT) as well as DCT. The experimental results revealed that embedded data could be read out with almost 100% accuracy in both cases, where the embedded watermarked image could hardly be observed. We also found that the influence of JPEG compression, which is commonly used in digital cameras, was very small.

Tunable Infrared Emission From Printed Colloidal Quantum Dot/Polymer Composite Films on Flexible Substrates

Abstract: A simple and robust device structure for a flexible, multicolor infrared (IR) display is described. The display operates by optical downconversion of AC-driven blue phosphor electroluminescence using different-sized, IR-emitting colloidal quantum dots. Deposition of the IR emissive layer via inkjet printing facilitates side-by-side multicolor pixel definition with low material losses.

Electrophoretic Display Controller Integrated With Real-Time Halftoning and Partial Region Update

Abstract: Electrophoretic displays (EPDs) have become the main solution to electronic paper because of its invariably reflective and bistable properties. With different requirements of display resolution, speed, and contrast ratio, the electronic paper (E-paper) designers may adopt different types of electrophoretic material and active matrix backplane for building the system. The driving waveforms should be also customized for accommodating different application specifications and environment temperature. In this paper, we present a configurable EPD controller which can support various application specifications. In addition to providing a new architecture of compacted waveform lookup tables, the controller supports partial image update and integrates a real-time halftoning engine for improving image quality. The design has been implemented on a field-programmable gate array (FPGA) and tested with several real EPDs.

Five-Primary-Color LCDs

Abstract: We demonstrate a wide color gamut and high brightness LCD TV using a conventional cold cathode fluorescent lamp (CCFL) backlight with five-primary (red, green, blue, yellow, and cyan) colors. Without changing the CCFL backlight and pixel size, the color gamut is widened from ~72% to ~90% and meanwhile the white brightness is increased by more than 20%, as compared to the three-primary. We also validate our simulation results using a 32" five-primary multi-domain vertical alignment LCD TV prototype. The agreement is reasonably good.

Method to Remedy Image Degradations Due to Facet Braiding in 3D Integral-Imaging Monitors

Abstract: One of the main challenges in 3D integral imaging (InI) is to overcome the limited depth of field of displayed 3D images. Although this limitation can be due to many factors, the phenomenon that produces the strongest deterioration of out-of-focus images is the facet braiding. In fact, the facet braiding is an essential problem, since InI 3D monitors are not feasible if the braiding problem is not solved. In this paper, we propose a very simple method for overcoming the facet braiding effect which is a serious limitation for realization of 3D TV based on InI. Hybrid experiments are presented to verify the theoretical analysis.

A New Compact Low-Power High-Speed Rail-to-Rail Class-B Buffer for LCD Applications

Abstract: This paper addresses a very compact low-power class-B buffer amplifier topology for large-size liquid crystal display applications. The proposed buffer achieves high-speed driving performance, draws a small quiescent current during static operation and offers a rail-to-rail common-mode input range. The circuit provides enhanced slewing capabilities with a limited power consumption by exploiting two current comparators embodied in the input stage, which sense the input signal transients to turn on the output stage transistors. A rail-to-rail stacked mirror differential amplifier is used to amplify the input signal difference and supply the bias voltages for the output stage. Post-layout simulations show that the proposed buffer can drive a 1-nF column line load within 1.8-?s settling time under a full voltage swing, while drawing only 3.5-?A static current from a 3-V power supply. Monte Carlo results finally confirm an excellent degree of robustness of the proposed topology.

Parallel Optics in Waveguide Displays: A Flat Panel Autostereoscopic Display

Abstract: In order to demonstrate the Wedge as a parallel optic we have built a flat panel multi-projector autostereoscopic 3D display. The bulk, otherwise inherent in such displays, has been eliminated by use of a wedge-shaped light-guide. Two 280-mm (11") diagonal VGA resolution views were formed on a 406-mm (16") diagonal screen by pointing a pair of LED-illuminated pico-projectors measuring 115 X 50 X 22 mm into the 20-mm thick input face of a 710-mm long acrylic wedge. Distortions introduced by the Wedge were reduced to less than 2% by predistortion algorithms and distortion between views was less than 0.4%. Between the projectors was placed an infrared camera which imaged objects placed directly in front of the 3D screen.