Advanced Display Research Articles

Flame-made Y2O3:Yb3+/Er3+ upconversion nanoparticles: Mass production synthesis, multicolor tuning and thermal sensing studies

Developing a rapid and continuous synthesis method for scalable production of upconversion nanoparticles (UCNPs) plays an important role in the applications of advanced color display, high-resolution biomedical imaging and precise optical thermometry. Here, for the first time, we report the multicolor tunable upconversion luminescence (UCL) in Y2O3:Yb3+/Er3+ (x/1 mol%) UCNPs with the average size of ∼14 nm, which were successfully fabricated by liquid-fed flame aerosol synthesis with a high production rate of ∼40 g h−1. Under the excitation of 980 nm continuous-wave (CW) laser, the UCL color can be efficiently modulated from green to red and the red-to-green (R/G) UCL intensity ratio is enhanced dramatically as the doping concentration of Yb3+ ions increases from 1 to 15 mol%. The UCL color manipulation can be ascribed to the cross-relaxation (CR) and the energy back transfer (EBT) processes between Yb3+ and Er3+ ions, and it was proved by investigating the dependence of UCL on the pump power and the decay lifetimes of 4S3/2 and 4F9/2 states. Moreover, the coefficients of CR and EBT processes were also calculated by a rate equation model, and the results suggest that they are efficient in Y2O3 host. In addition, the optical thermal sensing performance was also evaluated by analyzing fluorescence intensity ratio (FIR) of the thermally coupled levels (2H11/2, 4S3/2) of Er3+ ions in Y2O3:Yb3+/Er3+ (1/1 mol%) UCNPs, achieving an excellent thermal sensitivity of 0.0196 K−1 at 543 K.

Highly Adhesive and Sustainable UV/Heat Dual-Curable Adhesives Embedded with Reactive Core-Shell Polymer Nanoparticles for Super-Narrow Bezel Display.

To achieve the seamless characteristics of displays, liquid crystal (LC) devices need a super-narrow bezel design. This device architecture can be constructed using functional adhesives that possess excellent physical and chemical properties. In this study, mechanically robust ultraviolet (UV)/heat dual-curable adhesives with outstanding reliability and processability have been fabricated using reactive poly(methyl methacrylate) (PMMA)/polyethyleneimine (PEI) core-shell nanoparticles. Their curing characteristics, narrow drawing processability, adhesive strength, elongation at break, and the contact contamination of LCs have been investigated. Compared to conventional adhesive material, the proposed adhesive containing multifunctional PMMA/PEI nanoparticles afforded a high adhesion strength of 40.2 kgf cm−2 and a high elongation of 64.8% due to the formation of a firm crosslinked network with matrix resins comprising bisphenol A epoxy resin and bisphenol A glycerolate dimethacrylate. Moreover, the proposed adhesive showed an excellent narrow drawing width of 1.2 mm, which is a prerequisite for super-narrow bezel display. With regard to LC contamination, it was found that the level of contamination could be remarkably reduced to 61 µm by a high-temperature curing process. This study makes a significant contribution to the development of advanced display, because it provides robust and sustainable display adhesives based on nanomaterials, thereby enhancing the life and sustained operability of displays.

P‐82: Color Flexible Waveguide Display using Polymer Stabilized Liquid Crystal

In this paper, we report an advanced color flexible waveguide display which consists of two flexible plastic substrates and a sandwiched layer of liquid crystal/polymer composite. The display is edgelit by white and color (R, G, and B) LEDs. In the absence of applied voltage, the liquid crystal is in a uniform aligned state and is transparent, and the incident light is waveguided through the display and no light comes out of the front plane of the display. When a voltage is applied, the liquid crystal is switched to a poly‐domain state and becomes scattering, and the incident is scattered out of the front plane of the display. The display does not need polarizers and is thus compatible with plastic substrates with non‐uniform birefringence. It has sub‐ms response time and thus color sequential scheme can be used to display full color images. This flexible display has a big advantage in terms of energy efficiency because it does not need color filters and polarizers, and is suitable for transparent display application.

A Smartphone Integrated Hand-Held Gap and Flush Measurement System for in Line Quality Control of Car Body Assembly.

This paper presents the design and the characterization of a portable laser triangulation measurement system for measuring gap and flush in the car body assembly process. Targeting Human in the Loop (HILT) operations in the manufacturing sector, and in line with the vision of human empowerment with Industry 4.0 technologies, the instrument embeds features to ease operators’ activity and compensate possible misuse that could affect the robustness and the quality of data acquired. The device is based on a smartphone integrated with a miniaturized laser triangulation system installed in a cover. The device embodies additional sensors and control systems in order to guarantee operators’ safety (switching on and off the laser line based on specific conditions), support operators during the measurement execution task, and optimize the image acquisition process for minimizing the uncertainty associated to the measurement. The smartphone performs on-board processing and allows Wi-Fi communication with the plant IT infrastructure. Compliance to Industry 4.0 requirements is guaranteed using OPC-UA (Open Platform Communications—Unified Architecture) communication protocol enabling the exchange of live data with the plant middleware. The smartphone provides also an advanced high-resolution color display and well proven and ergonomic human–machine interfaces, which have been fully exploited in the design. The paper introduces the system optical layout and then presents the algorithms implemented to realize the gap and flush measurement. The paper finally presents the calibration of the instrument and estimates its calibration uncertainty in laboratory conditions. Then it discusses how performance decays when the operator handles the instrument on a reference car body. Finally, it shows the analysis of uncertainty when the device is used on real car bodies of different colors in a production line. It is observed that the measurement uncertainty of the whole measurement chain (measurand + instrument + operator + uncontrolled environmental conditions) is larger than the instrument calibration uncertainty because the measurement process is affected by the operator and the variable conditions of the production line.

Size-Selective ZnO Nanocrystals as Spectral Energy Converters for Use in Advanced Display Devices.

In this paper, we report the synthesis of size-selective zinc oxide (ZnO) nanocrystals by three different techniques namely, auto-combustion, co-precipitation and atomizer and their effective energy conversion from harmful ultra-violet (UV, 365 nm) to visible green light. All the three methods are facile and convenient for the controlled synthesis of ZnO nanocrystals with an average crystallite size ranging 12-35 nm. The structural characterization using XRD revealed that the phase of ZnO nanocrystals was wurtzite. The morphology of the ZnO nanocrystals in all the three cases was found to be spherical and uniform as determined by High Resolution Transmission Electron Microscope. The novelty of the current work is to synthesize highly luminescent ultra-small ZnO nanocrystals without any dopant and their possible use as efficient spectral converters in displays. This result is further supported by steady-state photoluminescence spectra recorded under UV (365 nm) radiation as excitation. The presence of quantum confinement effect and increased surface to volume ratio perfectly established that ZnO nanocrystals synthesized by various routes have significant impact in the fields of optoelectronics, biomedical fields and advanced active display devices.

A brief review of innovative strategies towards structure design of practical electronic display device

Display devices have significantly changed our daily life for decades, from the watches, television, to the laptop and smartphone. As the desire of advanced display device with high-resolution, long operation life and lightweight properties, several display techniques have been demonstrated. There are mainly four types of electronic display device: cathode ray tube (CRT), liquid-crystal display (LCD), organic light-emitting diode (OLED), and micro-LED. Due to the different working principles and device structures, each type of display device has its special characteristic properties. The performance of devices could be adjusted through the material selection or device design. With careful device structure regulation, not only the efficiency but also the stability would be improved. Herein, a brief review of innovative strategies towards the structure design is presented.

Transparent carbon nanotube web structures with Ni-Pd nanoparticles for electromagnetic interference (EMI) shielding of advanced display devices

Electromagnetic interference (EMI) has become an increasingly severe problem with the advancement in the development of electronic devices. In this study, an EMI shield was fabricated using a complex web structure made of Ni, Pd, and carbon nanotubes (CNTs). The Ni-Pd nanoparticles were evenly distributed on the surface of the CNTs. Samples with various thicknesses, specifically 10, 30, 50, and 100 nm, were fabricated and characterized. The results confirmed that the samples exhibited excellent and uniform electrical conductivity, flexibility, and transparency. In addition, the 100 nm thick shield demonstrated the capability of blocking 99.27% of the incident EMI and was successfully applied to a commercialized cell phone display.

Grain Boundary Enhanced Photoluminescence Anisotropy in Two‐Dimensional Hybrid Perovskite Films

AbstractThe boundaries between crystalline grains in hybrid perovskite films are beneficial for carrier dissociation, and may also serve as recombination centers to alter the photoluminescence property. Herein, it is shown that the grain boundaries can significantly enhance the anisotropy of photoluminescence from two‐dimensional (2D) hybrid perovskite films. The measurement of carrier densities shows that the grain boundaries generate an in‐gap state, which results in an additional red‐shifted photoluminescence band due to its emissive nature. Interestingly, the light emission of the in‐gap state appears only in the direction parallel to the film, corresponding to the in‐plane dipole transition as reveled by the measurement on photoluminescence polarization. These results demonstrate the tunable anisotropic photoluminescence from 2D perovskite materials toward the construction of directionally dependent light sources for advanced display application.

Glasses-Free 3-D and Augmented Reality Display Advances: From Theory to Implementation

Four of the most viable glasses-free three-dimensional display methods were chosen for our research at NTU's Advanced Displays Laboratory. Our multilayer light field display enables a smaller form factor. Faster algorithms combined with horizontal parallax-only speed-up Tensor Display computation time. A spin-off from this is an augmented reality light field near-eye display with focus cues. Our head-tracked displays use a directional backlit liquid crystal display panel to produce multiple sets of exit pupil pairs that employ a head tracker to follow the users’ eyes. This enables a ‘plug and play solution’ where existing content can be used without resolution loss. We have developed three different spatio-temporally multiplexed super multiview display systems based on liquid crystal displays, organic light-emitting diodes and fast projectors. In this article, the background, status of the prototypes and their performance are explained, and the future direction of our research is described.

Trichromatic and Tripolarization-Channel Holography with Noninterleaved Dielectric Metasurface

Metasurfaces hold great potentials for advanced holographic display with extraordinary information capacity and pixel sizes in an ultrathin flat profile. A dual-polarization channel to encode two independent phase profiles or spatially multiplexed meta-holography by interleaved metasurfaces are captivated popular solutions to projecting multiplexed and vectorial images. However, the intrinsic limit of orthogonal polarization-channels, their crosstalk due to coupling between meta-atoms, and interleaving-induced degradation of efficiency and reconstructed image quality set great barriers for sophisticated meta-holography from being widely adopted. Here we report a noninterleaved TiO2 metasurface holography, and three distinct phase profiles are encoded into three orthogonal polarization bases with almost zero crosstalk. The corresponding three independently constructed intensity profiles are therefore assigned to trichromatic (RGB) beams, resulting in high-quality and high-efficiency vectorial meta-holography in the whole visible regime. Our strategy presents an unconventionally advanced holographic scheme by synergizing trichromatic colors and tripolarization channels, simply realized with a minimalist noninterleaved metasurface. Our work unlocks the metasurface's potentials on massive information storage, polarization optics, polarimetric imaging, holographic data encryption, etc.

Analysis of Low profile head up display using light-guided technology

Light guided head-up display is an advanced display technology that realizes miniaturization and lightweight. It is very suitable for the increasingly stringent requirements of assembly space for HUD equipment in avionics and vehicle cockpits. This paper describes the basic principle of avionics light guided head-up display technology its technological advancement and feasibility, proposes a new type of light guided head-up display system, and analyzes the essential elements of light guided display technology in engineering application of head-up display for the first time. In this study, a polarization splitter array was embedded in the planar waveguide combiner to improve the transmittance of exterior light and the efficiency of light bearing virtual image and suppress the " window-blinds effect" of light guided head-up display. Experiments show that the transmittance rate of Combiner is over 80%, the imaging efficiency is better than 10%, and the virtual image is clear, uniform and continuous. This study is helpful to promote the application of the light guided display technology in head-up display system. The light guided display technology is expected to be developed in the field of avionics and vehicle fields.

Greatly amplified spontaneous emission of colloidal quantum dots mediated by a dielectric-plasmonic hybrid nanoantenna

Abstract Optical nanoantennas can efficiently harvest electromagnetic energy from nanoscale space and boost the local radiation to the far field. The dielectric-metal nanogap is a novel design that can help to overcome the core issue of optical loss in all-metal nanostructures while enabling photon density of states larger than that in all-dielectric counterparts. This article reports that a crystalline spherical silicon nanoparticle on metal film (SiNPoM) nanoantenna can largely enhance the spontaneous emission intensity of quantum dots by an area-normalized factor of 69 and the decay rate by 42-fold compared with quantum dots on glass. A high total quantum efficiency of over 80%, including ~20% for far-field radiation and ~60% for surface plasmon polaritons, is obtained in simulation. Thanks to not only the low optical loss in dielectric nanoparticles but also the appropriate gap thickness which weakens the non-radiative decay due to the quenching from metal. Mie resonant modes additionally provide the flexible control of far-field emission patterns. Such a simple optical nanoantenna can be combined with various nanoscale optical emitters and easily extended to form large area metasurfaces functioning as active regions in light-emitting devices in applications such as advanced display, wireless optical communication, and quantum technology.

The Proportion of Latent Tuberculosis Infection in Naive Lung Cancer Patients at Persahabatan Hospital Jakarta

Background: Lung cancer and pulmonary tuberculosis (TB) are two major public health problems associated with significant morbidities and mortalities. The increased prevalence of active TB and latent TB reactivation in lung cancer patients and negative effect of pulmonary TB in lung cancer prognosis needed screening of lung cancer patients for latent TB infection (LTBI). This study aimed to determine the proportion of LTBI in lung cancer patients, their characteristics and the relationship between them.
 Methods: This study used cross-sectional design. Collecting sample used consecutive sampling of 86 newly diagnosed treatment-naive lung cancer patients from RSUP Persahabatan in 2015 to 2016. The presence of LTBI was determined by Quantiferon-TB Gold-In-Tube (QFT- GIT) after having Mycobacterium TB not detected result from Xpert MTB/RIF sputum test. Demographic characteristics and cancer-related factors associated with LTBI were investigated.
 Results: The results of latent TB tests were IGRA(+) 12.8%, IGRA(-) 68.6% and IGRA(I) 18.6%. Number of male patients with lung cancer with latent were 68.6%, as many as 55.8% were immunized with BCG, 4.6% had close contact with TB and 64% were using smoking. Most types of cancer were adenocarcinomas (77.9%) with advanced stage (82.6%) and general display status 2 (50%). The characteristics that show an association with IGRA results are the location of the cancer and the total lymphocyte count.
 Conclusion: The proportion of latent TB in lung cancer patients at the RSUP Persahabatan was 12.8%. The location of the cancer associated with the area of typical TB was related to latent TB, although it cannot be canceled. Results of IGRA(I) in lung cancer patients with low total lymphocyte counts prove IGRA sensitivity in the protection of latent TB infection in immunocompromised patients. (J Respir Indo. 2019; 39(4): 256-65)

30.1: Invited Paper: Novel Emissive Projection Screen for Advanced Display Applications

A novel emissive projection display (EPD) was recently developed in Sun Innovations. It comprises of a fully transparent emissive screen made from a set of fluorescent nano‐materials, and a dark light digital image projector. The haze‐free emissive screen can be applied to any glass windows or windshield, without affecting visible light transmission. The digital “excitation” projector can be built on either a DLP (digital light processor) or a laser scanner display engine.This display combines the best of both world from conventional projection and emissive display technologies. Like projection display, the screen has no pixel structure and can be manufactured roll‐to‐roll; the display is scalable. Like plasma or CRT, the display is emissive with superior image quality and large viewing angles. It enables a fully transparent display on windows or windshields. The transparent emissive coating can also be applied to a pitch‐black substrate, for an innovative front projection display on black screen, with superior image contrast at low projection power.In this article, a full‐color EPD will be presented, with a color Gamut approaching 100% of HDTV color standard (Rec.709). This fundamentally new display platform can enable multiple major commercial applications, including a fully‐transparent emissive display on the glass window of vehicles and buildings with unlimited viewing angles. It also projects a high‐contrast emissive display on a pitch‐black emissive screen in ambient light, with similar image quality as OLED.

A facile synthesis of Mn doped CsPbCl3 perovskite with high photoluminescence properties

Manganese (Mn)-doped CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) has attracted tremendous interests recently, since the partial replacement of Pb with Mn can significantly enhance the photoluminescence quantum yields (PL QYs) of the QDs and achieve bright yellow light for advanced display applications. The present paper develops a halide-rich method to synthesize Mn-doped CsPbCl3 QDs by using MnO2 instead of MnCl2. X-ray photoelectron spectroscopy (XPS) measurements confirm that Mn2+ was located in the CsPbCl3 QDs lattice. The PL tests demonstrate a PL QY value up to 66% when the molar feed ratio of Pb/Mn/Cl is 1:1:8.

Atlases and Systems Theory within Systematic Cartography

Atlases and Systems Theory within Systematic Cartography

Ag/Au Alloyed Nanoislands for Wafer-Level Plasmonic Color Filter Arrays

Alloyed metals in nanoscale exhibit some intriguing features that are absent in mono-metallic nanostructures. Here we report silver and gold alloyed nanoislands with high tunability of localized surface plasmon resonance (LSPR) wavelength in the visible range for wafer-level plasmonic color filter arrays. The nanofabrication includes two simple steps of concurrent thermal evaporation of Ag and Au grains and solid-state dewetting of the as-deposited nanocomposite thin film. The alloy ratio during the evaporation precisely tunes the LSPR wavelengths within 415–609 nm spectrum range. The elemental composition map reveals that alloyed nanoislands are completely miscible while preserving uniform size, regardless of the alloy ratio. Besides, the multiple lift-off processes and thermal dewetting of Ag/Au nanocomposite thin films successfully demonstrate the wafer-level nanofabrication of plasmonic color filter mosaic. Each plasmonic color pixel comprises different alloy ratio and efficiently transmits colors ranging from cyan, yellow, and magenta. The transmission spectra transposed onto a CIE 1931 color map show comparable color diversity to the plasmonic color filters fabricated by conventional e-beam lithographic techniques. This novel method provides a new direction for large-scale and visible plasmonic color filter arrays in advanced display or imaging applications.

Physical Manipulation of Lanthanide‐Activated Photoluminescence

AbstractVersatile manipulation of lanthanide photoluminescence not only enables a more thorough understanding of the luminescent mechanism, but also promotes their widespread applications including advanced display and security, bioimaging and biotherapy, and sensors. The traditional chemical methods, engineering of composition, concentration, size, morphology, and surface defects, can easily tune the excitation, energy transfer and emission processes and have been frequently used. Despite the powerful ability to control luminescence intensity and selectivity, these chemical approaches suffer from cumbersome synthesis processes and are usually time consuming and irreversible. Recently, there have been numerous examples of physical approaches realizing in situ, real time, and reversible luminescence manipulation for certain materials under a given excitation. Herein, the existing physical strategies comprising temperature, magnetic field, electric field, and mechanical stress are summarized. For each approach, the action mechanism, material design, applications, as well as current challenges are discussed, and possible development directions and broadening of the potential application areas are considered.

High brightness and efficiency of polymer-blend based light-emitting layers without the assistance of the charge-trapping effect.

Polymeric light-emitting materials have been developed recently as an attractive solution-processable alternative to conventional vacuum-deposited small molecules in organic/polymeric light-emitting diodes, but they are still limited in terms of their performance, especially with low luminance and efficiency. We report on some noteworthy characteristics of a new type of single emitting layer (EML), composed of a blend of a host blue-emitting polyspirobifluorene-based copolymer and a guest yellow-emitting poly(p-phenylene vinylene) derivative copolymer. These host and guest polymers have nearly identical highest occupied molecular orbital levels of about 5.2 eV, and lowest unoccupied molecular orbital levels of about 2.4 eV and 2.9 eV, respectively, minimizing the prevailing charge-trapping properties of their blend. Even in the absence of the charge-trapping effect, it is shown that very bright green electroluminescent (EL) emission with a maximum luminance of ~142,000 cd/m2 can be realized for the blended host:guest EML at a moderate concentration (~5 wt%) of the guest polymer. Current efficiency is also observed to be up to ~14 cd/A, which is much higher than those (3.6~5.1 cd/A) of reference devices with pure host or pure guest polymeric EMLs. Moreover, there is a small change in green color emission, with CIE coordinates of (0.35, 0.60) even at high luminance, showing good color stability of the EL emission from the blended EML. These significant improvements in device performance are mainly attributed to efficient Förster resonance energy transfer between the host and guest polymers in the blended EML. Together with its simple structure and easy processability, the high brightness and efficiency of our blended polymeric EML provides a new platform for the development of solution-processable light-emitting devices and/or advanced emissive display devices.

Bi-photonic reduction of anisotropic Ag nanoparticles for color-tunable hologram reconstruction.

Efficient optical phase modulation is essential for information processing. The polarization response of metallic nanoparticles plays a key role in the formation of vector hologram. Commonly, Ag nanoparticles reduced by incoherent UV lamp tend to grow in isotropy, which is unsuitable for the formation of polarization hologram and the resultant multicolor holograms recording-readout in polarization channels. Here, the Ag nanoparticles storage with high polarization-sensitivity and anti-radiation interference are realized via bi-photonic irradiation from UV and visible lasers with participation of electron-acceptor. For the first time, the orthogonal polarization storage efficiency of the system is higher than that of the parallel mode. Color-tunable holographic reconstruction by polarization-multiplexing is achieved. This work provides a significant research strategy for stable, high-density data storage and advanced display.