Chromatic characterization of novel multicolor reflective display with electrochemically size‐controlled silver nanoparticles

Multifunctional electrochromic materials that enable control of multiple colors, color density, and specular reflection are potential candidates for novel reflective display devices. In this research, we focus on Ag nanoparticles that exhibit various optical states based on their localized surface plasmon resonance (LSPR). Because the LSPR band depends on the size and shape of the nanoparticles, control of the morphology of Ag nanoparticles can lead to dramatic changes in color. In order to apply this color variation for display devices, we investigate here the electrochemical formation of size‐controlled Ag nanoparticles using a voltage‐step method that consists of an application of two successive different voltages (V₁ and V₂). The electrochemically deposited Ag nanoparticles appear red and blue depending on the time for V₂ voltage application. The color changes between the transparent and colored states are reversible. Then, we successfully demonstrate the first LSPR‐based multicolor electrochromic device in which reversible control of five optical states—transparent, silver mirror, red, blue, and black—is possible.     

Comparative study of the electrochromic properties of WO3 thin films

This paper deals with a comparison between the electrochromic properties of tungsten oxide obtained by vacuum evaporation of WO₃ powder, anodic oxidation of W sheets and thermal oxidation of tungsten oxides obtained by chemical vapour deposited (CVD) onto SnO₂ substrate. Good electrochromic performances have been obtained with CVD layers despite their polycrystalline morphology and also with anodic oxidized W sheets despite the stoichiometry of the material. The results are compared with those obtained with amorphous tungsten oxide films prepared by vacuum evaporation. Moreover, we have shown that the electrochromic properties of the oxide (colouring efficiency, switching speed) depend on the nature of the substrate used. An AC complex impedance measurement was used to show the influence of this substrate on the behaviour of the electrical interfaces.     

Sensitometric characteristics of an all‐solid‐state photoelectrochromic pixel for an electrochromic light‐addressable display

Abstract— An all solid‐state photoelectrochromic element (PECE) was developed on the basis of electrochromic layers of WO₃ and polyaniline with a layer of polymer electrolyte placed on a base of polyamidosulfoacid, in which a thin‐film CdS_xSe_1?x photoresistor was used as an electronic key. The dependence of the sensitometric characteristics of the PECE on the applied voltage was studied.     

基于Ag纳米粒子的LSPR传感器装置设计与实现

设计了一种集原位芯片制备和在线检测于一体的局域表面等离子体共振(LSPR)生物传感器装置,减少了检测过程中芯片移动产生的误差,并实现了小型化、在线化、简易化的目标。在该装置上利用电沉积法制备了Ag纳米粒子的LSPR芯片,实验测试结果表明:氧化铟锡(ITO)层厚度为23±5 nm时,在-1.4 V电位,制得折射率灵敏度为246 nm/RIU的LSPR芯片。     

Viewing‐angle‐switching device based on array of optical micro‐rods incorporated with electrophoretic material systems

We have successfully demonstrated a control device for a viewing angle that enables switching between two states, a wide‐viewing angle, and a narrow‐viewing angle. It is composed of a light‐transmitting portion formed with an array of optical micro‐rods and a shielding/transmitting changeable portion of cross stripes designed with electrophoretic material systems consisting of black particles and an optically transparent medium. When the black particles are fully dispersed in the optically transparent medium, the cross stripe portion plays the role of a non‐transmitting material as the shielding portion in a similar manner to a conventional viewing angle control film. When the black particles are completely gathered electronically to one side in the optically transparent medium, in contrast, the cross stripe portion filled by the optically transparent medium can transmit incident light. These functions allow us to select electrically either of two modes between a limited viewing angle and a non‐limited viewing angle. The optical properties for the limited viewing angle mode were +/?30° of the visible angle and 50% of the transmittance, and the one for the non‐limited viewing mode was 58% of the transmittance. The response time from the narrow‐viewing angle to wide‐viewing angle was 1 s at 20 V of applied voltage.     

Electrochromic devices using Fe(II)‐based metallo‐supramolecular polymer: Introduction of ionic liquid as electrolyte to enhance the thermal stability

We fabricated electrochromic (EC) devices with Fe(II)‐based metallo‐supramolecular polymer (polyFe), 1‐butyl‐1‐methyl‐pyrrolidinium bis(trifluoromethanesulfonyl)imide (BMPyr(NTf)₂) ionic liquid ( IL ), and Prussian blue (PB) as electrochromic layer, electrolyte layer, and counter layer, respectively. Thermal stability and ionic conductivity of BMPyr(NTf)₂ IL was measured by thermogravimetric analysis (TGA) and impedance analysis to be 380°C and approximately 7.8 × 10^?4 S/cm, respectively. The fabricated device showed reversible electrochromism between bluish‐violet and colorless by applying +3.0/?1.5 V alternately. The 65% of the original EC contrast remained in the device after the repeated changes for 100 cycles at 100°C.     

A new family of hybrid 4‐DOF parallel mechanisms with two platforms and its application to a footpad device

This paper proposes a new family of 4‐degrees‐of‐freedom (DOF) parallel mechanisms with two platforms and its application to a footpad device that can simulate the spatial motions of the human foot. The new mechanism consists of front and rear platforms, and three limbs. Two limbs with 6‐DOF serial joints (P ‐S‐P‐P) are attached to each platform and are perpendicular to the base plate, while the middle limb is attached to the revolute joint that connects the front and rear platforms. The middle limb is driven by the 2‐DOF driving mechanism that is equivalent to active serial prismatic and revolute joints (P_e ‐R_e ), or prismatic and prismatic joints (P_e ‐P_e ) with two base‐fixed prismatic actuators. Since the middle limb perpendicular to the base plate has 3‐DOF serial joints (P_e ‐R_e ‐R or P_e ‐P_e ‐R), two new 4‐DOF parallel mechanisms with two platforms can generate pitch motion of each platform, and roll and heave motions (1T‐3R) or pitch motion of each platform and two translational motions (2T‐2R) at both platforms, according to the type of the 2‐DOF driving mechanism. Kinematic analyses of the 1T‐3R mechanism were performed, including inverse and forward kinematics and velocity analysis. Based on the 1T‐3R mechanism, a footpad device was designed to generate foot trajectories for natural walking. © 2005 Wiley Periodicals, Inc.     

Analysis of electro‐optical properties of polymer‐stabilized OCB and the application to TFT‐LCDs

Abstract— A 9‐in. full‐color polymer‐stabilized OCB TFT‐LCD with stable bend alignment in the absence of an electric field was developed. The condition of the polymer stabilization, the characteristics of UV‐curable monomers, and their influence on the configurations of the polymer network in the cell were studied. Possible models of the configuration were proposed and their relationship to the electro‐optical properties was analyzed using a novel simulation method considering the distribution of anchoring effects from both alignment surfaces and the polymer network. It was suggested that a good performance such as high contrast ratio and fast response could be expected in the polymer network originating from newly developed monomers composed of multifunctional LC acrylates due to a relatively weak‐anchoring effect and presumably its localization near the alignment surfaces. By using the newly developed monomers under the optimized polymer‐stabilizing process, a high contrast ratio of 250:1 and fast response nearly equal to that of a conventional OCB cell were achieved.     

Effects of temperature and pressure on the structural and optical properties of ZnO films grown by pulsed laser deposition

ZnO thin films were deposited on fused silica via pulsed laser deposition (PLD) at substrate temperatures from 300°C to 800°C and ambient oxygen pressures ranging from 10-2 mTorr to 240 mTorr. X-ray diffraction (XRD) and Raman spectra indicated that wurtzite ZnO was obtained in all cases. The highly c-oriented ZnO films were obtained for oxygen pressures above 11 mTorr. The room-temperature photoluminescence (PL) spectra demonstrated that all the films exhibited strong near-band-edge (NBE) emission, while d...     

Adhesive properties study on the interfaces of AlN and metal of Pd,Ag and Cu

AlN is used as high power LED package material because of its excellent thermal conductivity. But its poor adhesive with metal is not compatible with the later processing sequence. The properties of the bonding between the deposited palladium,silver,copper and the clean Al-terminated (0001) surface of wurtzite AlN are investigated by using the density-functional theory. The results show that the sites of deposited metal atoms on N site are more stable than that on Al site. Relaxations are found at all the s...     

Exploring risk‐based testing and its implications

If software cannot be tested exhaustively, it must be tested selectively. But, on what should selection be based in order to maximize test effectiveness? It seems sensible to concentrate on the parts of the software where the risks are greatest, but what risks should be sought and how can they be identified and analysed? ‘Risk‐based testing’ is a term in current use, for example in an accredited test‐practitioner's course syllabus, but there is no broadly accepted definition of the phrase and no literature or body of knowledge to underpin the subject implied by it. Moreover, there has so far been no suggestion that it requires an understanding of the subject of risk. This paper examines what is implied by risk‐based testing, shows that its practice requires an understanding of risk, and points to the need for research into the topic and the development of a body of knowledge to underpin it. Copyright © 2004 John Wiley & Sons, Ltd.     

Improvement of electro‐optical properties of PSBP LCD using a double‐sided IPS electrode

Abstract— In this work, a low‐hysteresis polymer‐stabilized blue‐phase LCD is developed by controlling the polymerization temperature and using a double‐sided IPS (DS‐IPS) electrode. Compared to a conventional IPS LCD, this DS‐IPS LCD has a driving voltage of 45 V, which is lower than that, 62 V, of a conventional single‐sided IPS LCD. The transmittance is increased approximately 23%. The hysteresis is reduced to 0.44% which decreases as a function of the operating voltage. Furthermore, simulations of the maximum transmittance and operation voltage associated with the offset between the electrodes in the top and bottom substrates were also evaluated.     

Tuning of electrical and optical properties of organic LEDs using combinatorial device fabrication

The capabilities of combinatorial methods are presented in order to get a detailed understanding of the electrical and optical properties of organic light‐emitting devices (OLEDs), to optimize their performance, and to provide reliable data for device modeling. We show results on multilayer OLEDs ranging from the conventional copper‐phthalocyanine (CuPc)/N,N′di‐(naphtalene‐1‐yl)‐N,N′‐diphenyl‐benzidine (NPB) and tris‐(8‐hydroxy‐quinolinato)aluminum (Alq) tri‐layer device to double‐doped deep‐red‐emitting OLEDs.     

Large‐signal variability of microwave power amplifiers through efficient device sensitivity‐based physical modeling

In the present article they present a comprehensive variability analysis of microwave power amplifiers in various operating classes by means of a recently developed numerically efficient technique for the physics‐based variability analysis of devices operated in nonlinear conditions. Both a class A and a deep class AB power amplifier are considered, with the active device undergoing variations of main physical parameters such as doping, gate work function, and gate length. The results presented show for the first time that the physics‐based variability analysis of nonlinear circuits is feasible and allows for a direct link between the PA performance uncertainty and the active device technological parameter variations. Both deterministic and statistical variations are taken into account, showing that the approach of Donati Guerrieri et al. (2016) allows for an aggressive reduction in computation time with respect to the variability analysis by means of conventional approaches, while retaining very good accuracy for parameter variations up to 10% of their nominal value. The highest sensitivity of the class A stage is found for the drain efficiency, while the class AB stage has a more involved behavior, with the highest sensitivity shifting from the drain efficiency to the output power as the input power increases.     

Influence of alkyldiacrylate side‐chains on electro‐optical properties in liquid crystal/composite films

In order to realize a paper‐like display using polymer‐network liquid‐crystal (PNLC) films, an increase in backscattering intensity is required. The morphology of the films, and the molecular interactions between the liquid crystals and polymers forming the polymer network, both play an important role in determining film electro‐optical properties such as the driving voltage and the reflectance. We have analyzed several factors related to the morphology of the films. Aiming at a reduction in the driving voltage, the effects of alkyl side‐chains in diacrylates have been investigated. Based on the results, we successfully produced a prototype paper‐like display.     

High‐visibility 2‐D/3‐D LCD with HDDP arrangement and its optical characterization methods

Abstract— A 3.1‐in.‐diagonal 2‐D/3‐D LCD with a novel pixel arrangement, called horizontally double‐density pixels (HDDP), for high‐quality 3‐D images has been developed. 3‐D visibility has been improved by broadening the qualified stereoscopic viewing space (QSVS) where high‐quality 3‐D images can be seen. In order to evaluate the QSVS, optical characterization methods, based on the ergonomics for stereoscopy, such as 3‐D crosstalk, interocular luminance difference and 3‐D moiré have been proposed. The implementation results show that these methods can correctly evaluate high‐visibility autostereoscopic displays.     

Preparation of monodisperse polystyrene microspheres and optical performance of its diffusive‐agent application

Abstract— Two monodisperse polystyrene microspheres, 2.76 and 9.25 μm in diameter, were prepared by dispersion polymerization in an ethanol/iso‐propanol/water media. 2,2′‐azobis(isobutyronitrile) (AIBN) and poly(acrylic acid) (PAA) were utilized as the initiator and steric stabilizer, respectively. Optical properties including total transmittance (T%) and transmittance haze (H%) were determined when these two monodisperse polystyrene microspheres were applied as diffusive agents. This paper mainly discusses (1) different particle‐size effects and its hybrid behavior, (2) different thicknesses for the diffusion‐layer effect, and (3) the effects of diffusion‐layer arrangement and direction of incident light on the total transmittance (T%) and transmittance haze (H%).     

Characterization of micro‐cell discharge in AC‐PDPs by spatio‐temporal optical emission spectroscopy

Abstract— We have developed highly resolved spatio‐temporal optical emission spectroscopy to investigate the discharge characteristics of coplanar type ac plasma‐display panels (AC‐PDPs). Spatio‐temporal emission profiles were measured for relevant lines of atomic He, Ne, Xe, and ionic Xe in He‐Xe and Ne‐Xe systems with various Xe concentrations and total gas pressures. The surface‐discharge behavior in coplanar PDPs has been clarified.     

Elaboration and standardization of an optical fibre corrosion sensor based on an electroless deposit of copper

The goal of our present work is to develop and test an optical fibre corrosion sensor (OFCS) fabricated by an electroless copper film deposition onto an optical fibre core within the sensing region. In our case, corrosion monitoring was carried out by two methods: optical and electrochemical methods. The idea consists is to couple these two methods by correlating the parameters describing the optical detection and those which describe the electrochemical corrosion process. This approach, once is carried out, makes it possible to gain more precise information on degradation within hidden parts of metallic structures.     

The role of LiF buffer layer in tris‐(8‐hydroxyquinoline) aluminum‐based organic light‐emitting devices with Mg:Ag cathode

Abstract— The device characteristics of organic light‐emitting devices based on tris‐(8‐hydroxyqunoline) aluminum with a thin layer of LiF inserted at the ITO and organic interface or organic and Mg:Ag cathode interface were investigated. A thin layer of LiF can enhance the electron injection when it was inserted only between the organic electron‐transporting layer and the Mg:Ag alloy cathode, but can block hole injection when inserted between the ITO anode and the organic hole‐transport layer. By inserting both a 1.0‐nm LiF layer at side of the ITO anode and a 0.5‐nm LiF layer under the Mg:Ag cathode, the device, at a current injection of 10 mA/cm², exhibited the highest current efficiency of 8.2 cd/A and power efficiency of 1.93 lm/W for all the types of devices investigated in this study. Both the current efficiency and power efficiency of the device were improved by 1.2 times at a current injection of 10 mA/cm², compared to the standard device without any LiF buffer layer. This is due to the increased electron injection and decreased hole injection that off‐sets the imbalance of electron and hole injection and brings it towards the balanced injection of electrons and holes, thus reducing the non‐productive hole current.