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In this paper opto-electronic methods for adaptive camouflage for a soldier are presented. This work is part of the EU funded project ACAMSII, “Adaptive CAMouflage for the Soldier II”, a future soldier system to be developed and implemented that provides adaptive camouflage against all relevant sensor threats, ranging from visible to thermal IR and radar. The assessment of possible technologies for adaptation of the visual signature is presented and discussed. The three most promising technologies will be discussed in detail: LED, OLED and electronic paper. Concerning the optical properties this paper will focus mainly on single colours and intensities, not on pattern generation and evaluation. Optical properties like luminance and the impact of reflectance are studied and compared. Especially the appearance of LEDs embedded in a textile and the impact of reflected ambient light will be analyzed. A discussion of colour space properties as a function of illuminance and surrounding background textile is presented also. It turned out that OLED and electronic paper devices have considerable disadvantages compared to LEDs. Therefor LEDs are the most promising optoelectronic components to be used for adaptive camouflage in the visible spectral range. Concerning the NIR spectral range a discussion of the optical requirements and the application of NIR diodes in clothing will be presented also.

Electrowetting display (EWD) is the most potential technology among new electronic paper technologies. It not only has the advantages of electrophoretic display (EPD) technology but also can realize color video playback. Therefore, this technology has been widely studied in recent years. Driving waveform is a voltage sequence which can drive pixels to display gray scales in EWDs. As one of the key technologies, it directly affects the display effect of pixels. In this paper, we give a review of the display principle of EWDs and the research status of driving waveforms. At the same time, the contact angle hysteresis, charge trapping, and oil splitting are also reviewed, which can provide a reference value for designing driving waveforms.

Electrowetting display (EWD) has promising prospects in the electronic paper industry due to it having superior characteristics, such as the ability to provide a comfortable reading experience and quick response. However, in real applications, there are also problems related to dielectric deterioration, excess power consumption, optical instability and narrow color gamut etc. This paper reviewed the existing challenges and recent progress made in terms of improving the optical performance and reliability of EWD. First, the principle of electrowetting applied in small and confined configurations is introduced and the cause of the failure of the dielectric layer is analyzed. Then, the function of the pixel structures is described to avoid display defects. Next, electric signal modulations are compared in terms of achieving good image quality and optical stability. Lastly, the methods are presented for color panel realization. It was concluded that multi-layer dielectrics, three-dimensional pixel structures, proper electric frequency-and-amplitude modulation and an RGB color panel are expected to resolve the current limitations and contribute to designing advanced reflective displays.

The primary task of a battery is to store energy and to power electronic devices. This has hardly changed over the years despite all the progress made in improving their electrochemical performance. In comparison to batteries, electronic devices are continuously equipped with new functions, and they also change their physical appearance, becoming flexible, rollable, stretchable, or maybe transparent or even transient or degradable. Mechanical flexibility makes them attractive for wearable electronics or for electronic paper; transparency is desired for transparent screens or smart windows, and degradability or transient properties have the potential to reduce electronic waste. For fully integrated and self-sufficient systems, these devices have to be powered by batteries with similar physical characteristics. To make the currently used rigid and heavy batteries flexible, transparent, and degradable, the whole battery architecture including active materials, current collectors, electrolyte/separator, and packaging has to be redesigned. This requires a fundamental paradigm change in battery research, moving away from exclusively addressing the electrochemical aspects toward an interdisciplinary approach involving chemists, materials scientists, and engineers. This Outlook provides an overview of the different activities in the field of flexible, transient, and transparent batteries with a focus on the challenges that have to be faced toward the development of such multifunctional energy storage devices., ACS Central Science, 7 (2), ISSN:2374-7951

Electronic paper (i.e., e-paper) is a display technology that aims to imitate and substitute the conventional paper. Previous studies of e-paper mainly focus on evaluating or making practical use of its readability. However, there is little research to explore the potential of e-paper on input-oriented applications. In this paper, we introduce a document composition system named SwiftPad for e-paper. Specifically, SwiftPad renovates the famous TEX typesetting system, enabling users to compose high typographic quality documents on e-paper in a WYSIWYG (what you see is what you get), offline-first, and collaborative fashion. Building such a system on resource-constrained e-paper with low screen refresh rate creates unique challenges. In this paper, we identity these challenges and provides workable solutions. We also provide a preliminary evaluation of the new system.

The electrophoretic display (EPD) is the main solution to electronic papers, but most of them can display the image or text in black and white particles only. The users may prefer the EPD showing multiple colors rather than the black/white content only. In this paper, we introduce the driving system for a color EPD, which is composed of three kinds of particles. The system aims at optimizing the visual quality based on a new driving waveform by equipping with an optimization method for color and tone reproduction. The experimental result shows that the proposed EPD driving system can display three-color pictures with promising visual quality.

In our current world, active display technology creates a glut of energy demand to meet its illumination needs. This demand can be stymied by using reflective display technologies that require no active illumination, with some examples including: electronic paper using electrophoretic motion of ink particles, electrowetting of water/oil droplets, and interferometric modulators, all of which have been commercialized. However, due to the lack of active light sources, it is difficult to implement these reflective display technologies in low light environments (e.g. nighttime display). In this work, we report an experimental observation of multiple concentric circular rainbows from reflective microscale concave interfaces (MCIs), which are introduced by the reflection of optical rays within a polymer-embedded microsphere. Exit rays from a single edge and opposite edges will introduce completely different interference mechanisms depending on the illumination and observation conditions, which will result in different angle-dependent colors. By clarifying the mechanism behind this coloration phenomenon, as well as quantitatively mapping the generated color, the implementation of the MCI in smart signs and pixelated displays are demonstrated, showing angle-dependent color-changing reflected images that can be observed over a wide spatial angle range. This structural material will serve as a building block for the development of new platforms for light-matter interactions, on-chip sensors, anti-counterfeiting tools, and passive and smart color reflective displays. Intriguingly, we also demonstrate a smart MCI traffic sign for both visible and infrared wavelengths that will introduce extra signals for pattern and image recognition in order to enhance the safety of future autopilot/autonomous systems.

Background Display signage is ubiquitous and essential in hospitals to serve several clerical, operational, and clinical functions, including displaying notices, providing directions, and presenting clinical information. These functions improve efficiency and patient engagement, reduce errors, and enhance the continuity of care. Over time, signage has evolved from analog approaches such as whiteboards and handwritten notices to digital displays such as liquid crystal displays, light emitting diodes, and, now, electronic ink displays. Electronic ink displays are paper-like displays that are not backlit and show content by aligning microencapsulated color beads in response to an applied electric current. Power is only required to generate content and not to retain it. These displays are very readable, with low eye strain; minimize the emission of blue light; require minimal power; and can be driven by several data sources, ranging from virtual servers to electronic health record systems. These attributes make adapting electronic ink displays to hospitals an ideal use case. Objective In this paper, we aimed to outline the use of signage and displays in hospitals with a focus on electronic ink displays. We aimed to assess the advantages and limitations of using these displays in hospitals and outline the various public-facing and patient-facing applications of electronic ink displays. Finally, we aimed to discuss the technological considerations and an implementation framework that must be followed when adopting and deploying electronic ink displays. Methods The public-facing applications of electronic ink displays include signage and way-finders, timetables for shared workspaces, and noticeboards and bulletin boards. The clinical display applications may be smaller form factors such as door signs or bedside cards. The larger, ≥40-inch form factors may be used within patient rooms or at clinical command centers as a digital whiteboard to display general information, patient and clinician information, and care plans. In all these applications, such displays could replace analog whiteboards, noticeboards, and even other digital screens. Results We are conducting pilot research projects to delineate best use cases and practices in adopting electronic ink displays in clinical settings. This will entail liaising with key stakeholders, gathering objective logistical and feasibility data, and, ultimately, quantifying and describing the effect on clinical care and patient satisfaction. Conclusions There are several use cases in a clinical setting that may lend themselves perfectly to electronic ink display use. The main considerations to be studied in this adoption are network connectivity, content management, privacy and security robustness, and detailed comparison with existing modalities. Electronic ink displays offer a superior opportunity to future-proof existing practices. There is a need for theoretical considerations and real-world testing to determine if the advantages outweigh the limitations of electronic ink displays.

Electronic paper (e-paper) is a display technology that aims to imitate conventional paper. Currently most e-paper applications on handheld devices are restricted to digital book readers. Few studies explore the potential of e-paper on input oriented applications. In this paper, we introduce a novel e-paper application PaperWork, which allows users to offload their commonly used office applications from a PC to an e-paper device remotely. There are considerable challenges when building a system for a resource constrained e-paper device which we will highlight in this work. In addition to presenting a new e-paper system we also conduct a usability study of this system.

The aim of this study was to understand to what extent people can read e-paper devices under various conditions of ambient illuminance that can occur indoors. In this study, 110 young to elderly subjects participated in an experiment to evaluate the effects of 14 different levels of ambient lighting on their reading from three different electronic devises and paper text. The participants were asked to undergo a timed read task and then to evaluate the readability of two eReader devices (a regular electronic display and one with a front light) in comparison with a backlit liquid crystal device and conventional paper text. The results indicated that backlit and front lit devices are easier to read at less than 200 lx and the reflective device is easier to read at levels above 500 lx.

With the advance of the IT industry, the possibility for using handheld devices to read is increasing. However, few researches discussed the elderly users’ reading performance while using various displays under different ambient conditions. Consequently, this study investigated the effects of display type (plain paper, color electronic paper (e-paper), and transmissive light-emitting diode (LED)) and ambient illuminance (50, 500, 6000, and 12,000 lx) on the reading performance of young and elderly readers. The results of this study show that young participants achieved higher comprehension than did elderly participants. The interaction between display and ambient illuminance had a significant effect on users’ comprehension. Participants who used the transmissive LED as the reading media did not show significantly different comprehension at various levels of ambient illuminance. However, participants who used the plain paper and color e-paper display achieved higher comprehension performance at 500...

The inherent advantages of reflective e-paper displays (EPD) – wide viewing direction range and excellent readability even under bright sunlight – can be extended into low-light conditions by the addition of an integrated lighting unit (ILU) such as a front light. A methodology for predicting the viewing direction dependence of ambient contrast and color from display measurements and illumination models is here applied to reflective EPD where the ILU is switched on. The predictions can be used to optimize task lighting. The ILU improves the indoor performance of EPD without compromising their superior daylight performance.

The inherent advantages of reflective e-paper displays (EPD) — wide viewing direction range and excellent readability even under bright sunlight — can be extended into low-light conditions by the addition of an integrated lighting unit (ILU) such as a front light. A methodology for predicting the viewing direction dependence of ambient contrast and color from display measurements and illumination models is here applied to reflective EPD where the ILU is switched on. First results show that an ILU improves the indoor performance of EPD, and enables their usage in environments with illumination otherwise inadequate for reading.

Reflective displays are also widely used in display applications calling for ultra-low power consumption, sunlight readability, flexibility, low cost etc ., such as electronic paper (e-paper). “Bistability” means a display can retain a still image without power consumption in two states (usually black and white). Several mainstream reflective display technologies including electrophoretic, electro-wetting etc . will be introduced in this chapter.

As a special kind of binary image, halftone image is produced by digital halftoning and widely used in printing. In recent years, some consumer electronics apply halftone image for lost-cost liquid crystal display systems. However, few techniques are reported for securing the content of halftone images, although a variety of schemes have been developed for continuous-tone image encryption in literatures. This paper proposes an encryption scheme for digital halftone images based on the principle of reversible pairwise swapping. The encryption and decryption phases are symmetrical because of the reversibility. It also can be easily integrated into some emerging display technologies such as cholesteric liquid crystal display which is used in electronic paper book. This secure method is also applicable for binary image encryption. Extensive experimental results demonstrate the effectiveness and efficiency of the proposed method.

The electrophoretic display (EPD) has been widely applied on electronic readers (E-Readers) for displaying image/text contents. With a touch panel, the user can put annotations on the contents at will. However, none of the available E-Readers support the function of paintbrush, which allows the user to plot gray tone figures. This is because the EPD is a bistable display whose driving method is quite complicated. In this paper, we first discuss the issues of realizing paintbrush function on the EPD display controller and then propose a new signal processing engine for the paintbrush function. The engine contains four stages: 1) screening the detected pixel coordinates; 2) interpolating pixels; 3) performing image halftoning to generate more visual gray levels; and 4) driving the pixels to the target states. The experimental results show that the engine meets the real-time requirement to complete the pixel interpolation as well as produce the gray-tone traces.

Summary and Conclusions The role played by both dye and pigment colorants in thedigital still imaging process is of paramount importance.The initial input is the use of dyes and pigments to producethe RGB Bayer pattern on image-sensor colour filter arrayelements. The conversion of the initially captured greyscaleimage to a full-colour image is only made possible, onalmost all current digital cameras, by the presence of theRGB Bayer filter array. The role of cyanine, phthalocyanine,and azo-metal complex dyes as the recording layer for CD-R,DVD-R, and Blu-ray optical data storage systems cannot beunderestimated in the continued drive for high-capacitydigital image storage systems, and it is to be hoped thatspecific dyes will also play a part in future three-dimen-sional optical data storage systems when they eventuallyreach commercial fruition. Although many amateur pho-tographers still tend to rely on image-processing outlets toobtain hard-copy reflective prints from their digital imagefiles, and hence receive predominantly laser-optimal silverhalide images, many, including a high percentage ofprofessional photographers, prefer to use photorealisticnon-impact printing technologies. The most popular sys-tems include inkjet, thermal dye transfer, and electropho-tography. Each of these systems uses either dyes orpigments, and in the case of inkjet both are utilised. Theincreased popularity of non-impact printing to createphotorealistic colour prints created new challenges for therespective dye and pigment manufacturing industries. Forthe dye industry, the challenge was to generate newchromophores and/or higher-purity existing dyes for inkjetand thermal dye transfer, with key attributes such as highpurity, a high extinction coefficient, a narrow absorptionband, ease of transfer, non-toxicity, and good fastness tolight, water, and atmospheric gases. Although the structuresof commercially used thermal dye transfer dyes have notbeen disclosed, the structures of commercially successfulinkjet dyes, which include acid, direct, and passivatedreactive dyes, are predominantly in the public domain. Therole of dye and pigment colorants within the rapidlydeveloping electronic paper (e-paper) field is important forboth existing monochrome systems, e.g. the Amazon Kindlesystem, which uses carbon black and titanium dioxide, andthe potentially successful future colour systems, which willutilise either RGB or CYM dyes or pigments to generate full-colour photo-quality images on screen, together withmoving video images. Thus, it would appear that, althoughtechnological advances continue to be made within theimaging industry, the generation and reproduction of RGBadditive and CYM subtractive images, in whatever form,would seem to be reliant on the use of dyes and/or pigmentcolorants.

In this article, we disclose a method to fabricate the three-dimensional (3D) image on an optically rewritable (ORW) electronic paper (e-paper) by deploying the lenticular lenses array on the top of the ORW e-paper. Unlike other autostereoscopic 3D liquid crystal displays, our autostereoscopic 3D ORW e-paper is actually a green technology, which is without electrode and voltage. No electricity is needed to maintain the 3D image on the ORW e-paper. We can easily change a 3D image by erasing and rewriting with photoalignment technology.

We have quantified the image quality of color electronic paper (e-paper) by subjective evaluations and clarified the requirements for improving the image quality. In the color e-paper field, various display types have been developed with the focus on improving the display performances or manufacture costs. However, color e-papers are still under development, and the image quality is not sufficient when compared with printed papers, photographs and conventional displays. With respect to the image quality of color e-paper in the future, it is very significant to clarify how reflectance, contrast ratio, National Television System Committee (NTSC) ratio, and other factors affect the image quality. Therefore, we have quantified the image quality factors such as color reproduction, tone reproduction, and surface texture. From our experimental results, we could clarify the significant factors and the practical range of image quality of color e-paper. For instance, both the reflectance of approximately 30% or higher, contrast ratio of approximately 8:1 or higher, and NTSC ratio of 20% or higher are the requirements for obtaining subjective evaluation score that is equivalent to that of newspapers, which are read very widely.

Projected image on a screen is not always vivid enough when it is projected in a bright room. We generally have to choose either vivid image in a dark room or dull image in a bright room. We have suggested a new projection system which can realize high contrast image projection in a bright room. It is consisted of electronic paper screen, projector, and light-emitting diode room light. The electronic paper (e-Paper) screen alternates its whole surface white/black with 120 Hz. Room lights are controlled with the same frequency of 120 Hz with the opposite phase as that of the e-Paper screen. We have confirmed that our new system has achieved higher contrast than the conventional projection system and also enough readability of paper documents in the room simultaneously. We have thus confirmed that our new system can bring an ideal condition, for audience, which can realize a vivid image projection in a bright room.

The display quality, as well as the speed of electrophoretic displays (EPDs), is highly affected by the design of driving waveforms. A typical driving waveform contains the phases of image erase, particle activation, and driving each pixel to the target gray level. Due to the difficulty of modeling a complete EPD device, the designers still lack a systematic approach to driving waveform design. In this paper, we study the property of the viscosity of the suspension, characterize the response latency of the device, and propose a new driving waveform. The experimental results show that the proposed approach can effectively reduce driving time while still maintaining good image quality.

The electrophoretic display (EPD) has become the main solution to electronic papers, but there are several limitations when it is being driven. First of all, the optical response curve of the EPD is nonlinear and temperature sensitive. In addition, the number of gray levels that can be displayed is also quite limited. The image quality is unsatisfactory if the images shown on the panel are not preprocessed to increase the number of visual gray levels and compensate the characteristics of the EPD. In this paper, we present an integrated image tool to automatically estimate the reflectance function curves under different ambient temperatures, perform adaptive image halftoning to improve visual quality, and calibrate the image to compensate the nonlinear response of EPD. The proposed approach has been verified on practical EPD panels and promising results have been achieved.

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.

紙の読みやすさや扱いやすさと電子ディスプレイの利便性や省資源性を併せ持つ理想媒体をめざす電子ペーパーについて，その狙いや分類を示した上で最近の開発動向，試用状況，商品化動向について紹介する。電子ペーパー技術は，少なくともモノクロ表示では電気泳動方式をはじめとして読みやすい表示を実現しすでに実用領域に達している。電子ペーパー技術を用いた電子書籍装置および配信サービスは米国において2007年末以降の1年間で急速な市場の立ち上がりを見せており，日本でも学会予稿に使用する試みが意欲的に進められているなど，印刷物を置き換え可能な次世代媒体として大いに期待される。

The multi-channel and multi-platform technologies allow the mobility of information, which has a direct impact on the evolution of the electronic book. The change is dictated by the emergence of a new generation of electronic paper devices, as well as their own models of information management. In the present paper we review the electronic book concept and present the basic characteristics of the devices that can be found on the market; then we describe the elements needed to carry out projects that produce works designed for electronic ink devices. Las tecnologías multiplataforma y multicanal permiten la movilidad de la información, cosa que tiene una incidencia directa sobre la evolución del libro electrónico. El cambio viene dado por la aparición de una nueva generación de dispositivos de tinta electrónica, así como por los propios modelos de gestión de la información. En el presente trabajo se revisa el concepto de libro electrónico y se presentan las características básicas de los dispositivos que se pueden encontrar en el mercado, para a continuación exponer los elementos necesarios para la ejecución de proyectos de producción de obras para dispositivos de tinta electrónica.

This is both a historical overview of reader devices of electronic documents and a description of the current technology characterized by the so called “electronic paper”. Gyricon technologies are analysed as well as the electrophoretic screens and devices that use the electrowetting principle. A wide variety of file formats compatible with the different kinds of reader devices are shown, as well as the problems derived from reader incompatibility. The more outstanding models available in the market and their services are also described. A reflection is proposed about the different usages and their effectiveness, document dissemination, and the expectations that the e-readers have created regarding future development. Nowadays these devices make the reading of electronic documents easier and more comfortable.

A novel reflective color LCD without polarizer has been developed with using PDLC and retro-reflector. Bright color images including moving images are available with utilizing ambient light. Our novel LCD will create a new application area such as electronic paper.

紙とディスプレイの長所を共存させた快適に“読める”媒体として電子ペーパーが注目され，実用を目指した開発が精力的に進められている。本報告では，電子新聞・電子本などへの適用が期待されるこの新しい電子メディアに対する多様な期待の方向性についてまず整理を示す。そのうえで改めて電子ペーパーのねらい，実現形態，技術開発の現状，応用用途の見通しについて概説する。また電子ペーパーの目指す読みやすさに関する基礎研究として，ディスプレイ作業と紙上作業の差異に注目し，その作業性や疲労度について被験者を用いて定量評価を行った結果を紹介し，得られた知見についても述べる。

Readers of e-Books read words on electronic paper. We conducted an experiment in which 13 college students read electronic paper and conventional paper for 90 minutes better understand the degree of visual fatigue from such reading. The degree of their visual fatigue was measured before, during, and after reading. Results showed no significant differences in the levels of visual fatigue between the electronic and conventional reading. We conclude that electronic paper is a good reading display that is as gentle to the eyes as conventional paper.

There currently exists a sharp boundary, in both technological and design terms between graphic design for screen and for print. These distinctions stem from the nature of the broadcast environment. Each has its benefits-portability and extreme durability for books (running into thousands of years), interlinking and expandability for electronic design-and its distinct drawbacks.What if we could merge the best of these two worlds into one elegant whole? We could have a document with all that that entails; portable, durable, and cheap, but with web like features, such as search functions, linking and the ability to access other media? In principle, the technology is already here, but is it everything that the developers claim, and what should the designers' response be to such a media. In this paper, both questions are examined, and some surprising conclusions are drawn.

Wireless electronic price tag is designed with the Electronic Paper Displays' low power consumption, using STM32L152RD single-chip microcomputer as the core. Practice has proved that electronic price tag of low cost and power consumption can update the commodity information on the remote wireless price tag.

Playing videos on the electronic paper, which is composed of the electrophoretic display (EPD), is an attractive feature, but none of commercial EPDs supports it. This is because the response time of the EPD is much longer than liquid crystal displays. In addition, the number of gray tones shown on the EPD is quite limited, and the state transitions between successive frames can be achieved by complicated driving waveforms. These issues result in the difficulties of supporting video display function on the EPD. In this paper, we propose a new real-time signal processor for the EPD. The processor is composed of hardware modules for producing halftoned video frames, encoding video data, and sending driving waveform to the display in real time to show good quality of videos on the EPD.

The technological challenge for researchers working on the next generation of electronic paper is to render color as brightly as traditional paper, without increasing power requirements or end-user costs.