Display Panel Research Articles

Preview the Products on Display at Display Week 2022

Preview the Products on Display at Display Week 2022

Voice Controlled Wireless Electronic Notice Board Using Android

Abstract: The Advanced mobile technology opens the Scope to the widely usage of android app. The websites are disappearing more and the mobile phones are most prominent.It’s the time to change from the websites and to the other things like apps, which has become the part of our daily routine. In this paper we are introducing voice to text .apk file and it controls the Arduino by sending commands. It works on all the android platforms. Main concept of Voice controlled wirelesselectronic notice board is to show the messages on the scrolling display panel and to control them by using our voice commands. Previously we had seen GSM based electronic notice board; however by using speech controlled Notice board with Bluetooth technology has the additional advantage of ease of use. User has to speak through the “voice Arduino control” app in order control the messages displayed on notice board. Voice recognition is done by the Android. Firstly, user has to install this App application in his/her smart phone or laptop. For displaying purpose, we used P10 module led matrix display panel. The message will be scrolled like in railway stations. Bluetooth technology used for wireless part of the communication; it is used in this system to transmit and receive data wirelessly between the two connected devices. This helps us in transmitting any message with in a fraction of a second and also helps in eliminating any delay by simply sending a voice command which is much efficient compared to any other traditionally method of transmitting the message. Thus the proposed technology can be used in many of public places such as theshopping malls or commercial buildings like hospitals to alert the security system and also increase the awareness of the regarding emergency situations and avoid anypossible dangers. Keywords: Arduino, Voice Arduino control, P10 matrix display, Bluetooth module, Notice board

Broadband Enhancement of Anti-reflectivity for a High Angle of Incidence Using Nanocone Geometry.

The broadband antireflective (AR) effect for wide incident angles has a significant effect on the photoconversion efficiency of photovoltaics and visibility of large-format display panels. The fabrication of surface nanostructures has continued to attract research interest as an effective way to provide such optical performance. However, the effects of different nanostructure geometries are not fully understood, especially for wide-angle AR effects. In this work, we conduct a systematic analysis of the effect of periodic nanostructures such as nanocones (NCs) and inverted nanocones (INCs) on anti-reflectivity at high angles of incidence (AOIs) in terms of light scattering, guided-mode resonance (GMR), and internal reflections. NCs provide good coupling of light scattering and GMR because of their protruding geometry; hence, reduced reflectance can be obtained in the short wavelength region. Further, NCs exhibit relatively weaker GMR intensities and internal reflections, resulting in low reflectance in the long wavelength region. Therefore, NCs offer a superior broadband AR effect for high AOIs compared with INCs. Based on this analysis, we demonstrate an extremely low average reflectance (5.4%) compared to that of the bare substrate (34.7%) for the entire visible range at an AOI of 75° by fabricating NCs on both sides of the substrate.

Using virtualized multimedia tools for video conferencing solution integrated in teaching and learning environment

Interactive display panels are one of the most widely used display systems today in delivering high-quality teaching and learning experiences to the students and faculties around the globe as several hardware and software tools can be integrated with these interactive display panels so that more efficiency and interactivity can be done on these panels. In this research work, we are more focused on how we can securely manage these interactive display panels in teaching and learning environments and provide an integrated solution for the academic environment to protect these systems that are integrated with video conferencing solutions. The architectural design of the system and the integrated solutions, along with video conferencing capabilities in the teaching environment, need to be secure and should not be accessible to the intruders during teaching and learning. Hyper-convergence infrastructure provides a virtualization environment that can be used by the stakeholders for providing infrastructural elements like different operating systems for the teaching and learning environment. Video conferencing solutions can be deployed on different virtualization environments using hyper-convergence technology that can be accessed over the remote interactive display panels as per the request of the stakeholder who is using the interactive display panel in the classrooms and meeting rooms. Securing this hyper-converged infrastructure is important which can be achieved through virtualization technology. If one system is down, the entire teaching and learning environment can run without any latency in executing the teaching and meetings in the organization.

Foveated imaging by polarization multiplexing for compact near‐eye displays

AbstractWe demonstrate a multi‐resolution foveated imaging system for virtual reality, which is enabled by a single display panel with polarization multiplexing to significantly increase the angular resolution without scarifying the frame rate. By using a polarization‐dependent cholesteric liquid crystal reflector, we have achieved a 4.4× higher resolution density while maintaining a compact form factor.

Luminescence spectroscopy of CaAl12O19:Eu3+ and SrAl12O19:Eu3+ nanoparticles

Development of red-emitting phosphors have gained enormous interest in recent year, due to their great potential for biological applications as well as display panels and solid-state lighting. Here, we present luminescence spectroscopy of deep-red-emitting CaAl12O19 (CA6) and SrAl12O19 (SA6) nanocrystals doped with Eu3+. CA6:Eu3+ and SA6:Eu3+ hexagonal nanoparticles (NPs) were prepared via a solvothermal reaction followed by a post-annealing process at 1150 °C. The luminescence spectra were obtained both at 298 and 5 K. Unaccustomed for Eu3+, the strongest emission was observed to originate from the 5D0→7F4 transition. Furthermore, emissions from the higher excited states (5D1-3) of the f-configuration of Eu3+ were also observed in these NP hosts at room temperature. In addition to the bands assigned to Eu3+ on the high symmetry D3h site, additional bands assigned to lower symmetry charge compensated sites have been identified. Crystal field (CF) parameters were obtained for the Eu3+ ion in SA6 compound, and the energy levels were estimated theoretically, which agreed well with the experimental values.

가속센서 데이터 기반 반복 학습 제어 적용 디스플레이 패널 이송 로봇 경로 오차 보상에 대한 연구

Transfer robots for large-sized panels used in the display industry need to compensate for path error and reduce vibration. The iterative learning control (ILC) technique can simply compensate for the uncertainty of a control system in a repetitive motion. This study introduces an ILC compensation system applied with an accelerometer to a display panel transfer robot control system. The ILC technique was used to reduce the path error and vibration induced the flexibility of the large size robot. This method was applied to a robot system without the system model of the mechanical and measurement elements. To improve the iterative learning performance through the accelerometer, the ILC is configured by applying an acceleration element and time shift method to the PD-Offline ILC algorithm. In addition, based on the characteristics of repetitive motion, the ILC derives an acceleration data-based position estimation value. In this study, the ILC system and a large-sized panel transfer robot were implemented in MATLAB-Simulink with RECURDYN. The path errors and vibration level of the robot with a suggested ILC of 20 repeated learnings were reduced by more than 90%.

A Novel Multicategory Defect Detection Method Based on the Convolutional Neural Network Method for TFT-LCD Panels

Defects on thin film transistor liquid crystal display (TFT-LCD) panel could be divided into either macro- or microdefects, depending on if they are easy to be detected by the naked eye or not. There have been abundant studies discussing the identification of macrodefects but very few on microones. This study proposed a multicategory classification model using a convolutional neural network model to work with automatic optical inspection (AOI) for identifying defective pixels on the TFT-LCD panel. Since the number of nondefective pixels outnumbered the defective ones, there exists a very serious class-imbalanced problem. To deal with that, this study designed a special training strategy that worked with data augmentation to increase the effectiveness of the proposed model. Actual panel images provided by a mobile manufacturer in Taiwan are used to demonstrate the efficiency and effectiveness of the proposed approach. After validation, the model constructed by this study had 98.9% total prediction accuracy and excellent specificity and sensitivity. The model could finish the detection and classification process automatically to replace the human inspection.

Release and Gas-Particle Partitioning Behavior of Liquid Crystal Monomers during the Dismantling of Waste Liquid Crystal Display Panels in E-Waste Recycling Facilities.

Liquid crystal monomers (LCMs) are a class of emerging chemical pollutants; however, their release and gas-particle partitioning remain unknown. This study performed the first comprehensive analysis of a wide range of 93 LCMs in the ambient air of liquid crystal display (LCD) dismantling facilities. A total of 53 of the 93 target LCMs were detected in the air samples. The total atmospheric concentrations (gas and particles) of LCMs (∑LCMs) ranged from 68,800 to 385,000 (median of 204,000) pg/m3. Most LCMs were predominant in the gas phase, implying that their atmospheric transport would be mainly governed by gas rather than particle diffusions. Differential distribution patterns of the LCMs were observed due to their different atmospheric partitioning behaviors. Significant linear correlations were found between the gas-particle partitioning coefficients (KP) and the predicted subcooled vapor pressures (PL) and octanol-air partitioning coefficients (Koa) (p < 0.01). Compared with two equilibrium-state models, the experimentally observed particulate fractions (ϕ) fit better with the predicted values based on the Li-Ma-Yang (L-M-Y) steady-state model, and Koa was identified as a key factor determining the atmospheric fate pathways of LCMs. Our study highlights another new class of chemicals significantly contributing to the chemical mixture in the ambient air at e-waste recycling areas.

Depth-enhanced 2D/3D switchable integral imaging display by using n-layer focusing control units

ABSTRACT Depth of field (DOF) is one of the important parameters of three-dimensional (3D) displays. A two-dimensional (2D)/3D switchable display that can display both high-resolution 2D images and vivid 3D images with large DOF is an ideal purpose. In this paper, we propose a depth-enhanced 2D/3D switchable integral imaging display by using n-layer focusing control units (FCUs). Each layer of FCU is composed of a polarization switch and a polarization-dependent liquid crystal micro-lens array (LCMLA). According to the polarization state of incident light switched by the polarization switch, the polarization-dependent LCMLA can realize focusing effect or transmission effect, respectively. Because each layer of FCU has two optional optical effects and has different gap from the display panel, the combination of n-layer FCUs could generate 2 n -1 central depth planes, hence 2 n -1 sub-DOFs can be obtained for depth-enhanced 3D display. The 2D display mode can be easily realized when all layers of FCUs are transmission effect. We experimentally set up a prototype of the proposed 2D/3D switchable display with two-layer FCUs. The experimental results indicated that the proposed prototype can effectively increase the DOF of 3D display and realize 2D/3D switchable display as well.

Two Steps Forward and One Step Back?: US, EU and China’s Bilateral Antitrust Cooperation and International Trade

Greater antitrust enforcement is argued to have positive correlations with the promotion of international trade. By 2019, the US, the EU and China, as global trade powers, have formed and strengthened bilateral antitrust cooperation to seek greater enforcement. However, the impact of such development on international trade has remained underexamined. The article argues that irrespective of their different legal forces, the US-EU, US-China and EU-China antitrust cooperation share convergences at the optimum and minimum levels. Based on the case study of the US, the EU and China’s regulations of the international Liquid Crystal Display (LCD) panel cartel, the article illustrates that as the effects doctrine continues to serve as the main normative value underpinning antitrust cooperation, matured competition regimes lack the incentive to share information with new regimes, competition regimes converge to apply comity restrictively and the consultation mechanism plays a limited role in holding the sides accountable under bilateral cooperation. Consequently, international antitrust remains fragmented, positing restraints to trade. The article calls for reconsideration of the effects doctrine as part of the transnational normative repertoire shaping bilateral antitrust cooperation and for devising policy tools to guarantee minimum information exchange among agencies. US, EU, China, International Antitrust, Bilateral Cooperation, Exchange of Information, Confidentiality, Comity, Consultation

End-to-end optimization of a diffractive optical element and aberration correction for integral imaging

In the integral imaging light field display, the introduction of a diffractive optical element (DOE) can solve the problem of limited depth of field of the traditional lens. However, the strong aberration of the DOE significantly reduces the final display quality. Thus, herein, an end-to-end joint optimization method for optimizing DOE and aberration correction is proposed. The DOE model is established using thickness as the variable, and a deep learning network is built to preprocess the composite image loaded on the display panel. The simulation results show that the peak signal to noise ratio value of the optimized image increases by 8 dB, which confirms that the end-to-end joint optimization method can effectively reduce the aberration problem.

Systematic strategy for high-performance small molecular hybrid white OLED via blade coating at ambient condition

Large-area organic light-emitting diodes (OLEDs) fabricated by solution process with low-cost are essential for practical applications. However, maintaining desirable uniformity and smoothness of prepared films are challenging with the enhancement of film size and layers. Reported herein is a systematic strategy of solvent and device structure engineering for designing small molecular hybrid white OLED (WOLED) via blade-coating. Benefiting from the uniform blade-coated films with low roughness about 1 nm as well as the balanced charge carrier transport, the blade-coated WOLED with hybrid fluorescence and phosphorescence (small area 0.1 cm 2 ) shows the maximum current efficiency (CE), power efficiency (PE), and external quantum efficiency (EQE) of 29.0 cd A −1 , 30.4 lm W −1 , and 11.6%, respectively. And the WOLEDs achieve low turn-on voltage ( V on ) of about 2.8 V. Meanwhile, the all-vacuum-based WOLED reaches maximum CE, PE, and EQE of 40 cd A −1 , 44.3 lm W −1 , and 15.9%, respectively. Remarkably, a larger area of the device (2 cm × 2 cm) with uniform emitting reaches peak EQE of 6.8% by blade-coating, notably, only a small amount of solution about 0.9 μL/cm 2 was consumed for blade-coated films. The high-performance and low-cost WOLED via blade-coating is ascribed to the facile strategy to improve the film morphology and the energy-level matching, which provides huge potential in display and flat panel lighting. Benefiting from the solvent and device structure engineering, the blade-coated hybrid white organic light-emitting diodes (WOLEDs) reach external quantum efficiencies (EQEs) close to 12% (small-area, 0.1 cm 2 ) and 6.8% (2 cm × 2 cm) with a small amount of solution about 0.9 μL/cm 2 . • Fabricating a hybrid white organic light-emitting diodes (WOLEDs) by blade-coating at ambient conditions. • Selecting the ideal solvents (solvent engineering) and electron-transporting layer for the highly efficient blade-coating WOLED which reaches the maximum EQE, power efficiency (PE), and current efficiency (CE) of 11.6%, 30.4 lm W −1 , and 29.0 cd A −1 , respectively. • Fabricating a blade-coated WOLED (2 cm × 2 cm) owning peak EQE of 6.8% with a small amount of solution of 0.9 μL/cm 2 .

Amorphous IGZO Thin-Film Transistor Gate Driver in Array for Ultra-Narrow Border Displays

A gate driver in array (GIA) design based on the amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) is developed for narrow border displays. In the design, each TFT in the gate driver circuits is divided into a certain number of smaller size devices, which can be placed in different subpixels. Therefore, the pixel aperture ratio loss is minimized, and uniform placement of the gate driver circuits over the pixel array area is able to be achieved. The proposed step-like repeating block structure further reduces the occupied area of the signal interconnects. A 12.4-inch fringe field switching (FFS) liquid crystal display (LCD) panel of ultra-narrow border (0.5 mm) is demonstrated with reliable operation based on this GIA design, proving its potential for practical applications.

Femtosecond Laser Machining of Flexible Printed Circuit Boards

As the demand grows for high-density electronic components and highly integrated printed circuit boards, femtosecond laser micromachining provides unique opportunities for creating fine conductive tracks and patterns on flexible printed circuit boards (FPCBs) without the use of a mask. Here, the effects of femtosecond laser power and pulse frequency on micromachining depth, surface roughness and copper content of the machined zone were investigated, and optimum laser parameters, i.e., laser power 280 mW and pulse repetition frequency 39.5 kHz, were achieved with the help of a 3D optical profilometer and energy dispersive spectroscopy (EDS). On this basis, a single conductive track with varying widths and two parallel conductive tracks with different widths/spacings were micromachined on FPCBs without noticeable substrate damage. The results indicate that a single conductive line with a feature width as small as 25 µm can be achieved, and two parallel copper tracks can be created with no evidence of the presence of copper residues between the tracks when the pre-defined spacing is no less than 45 µm . In order to achieve high micromachining accuracy, look-up tables that correlate measured widths/spacing of conductive tracks with the pre-defined ones were built.besides, machining conductive tracks with 135 degree corner is possible and by selecting optimized processing parameters. Finally, a driving circuit for a display panel was micromachined on FPCBs using femtosecond laser, and an average micromachining accuracy of 0.67 μm was achieved. This work will be quite useful for creating high density and precision patterns on FPCBs using femtosecond laser.

Holographic techniques for augmented reality and virtual reality near-eye displays

Near-eye displays are the main platform devices for many augmented reality (AR) and virtual reality (VR) applications. As a wearable device, a near-eye display should have a compact form factor and be lightweight. Furthermore, a large field of view and sufficient eyebox are crucial for immersive viewing conditions. Natural three-dimensional (3D) image presentation with proper focus cues is another requirement that enables a comfortable viewing experience and natural user interaction. Finally, in the case of AR, the device should allow for an optical see-through view of the real world. Conventional bulk optics and two-dimensional display panels exhibit clear limitations when implementing these requirements. Holographic techniques have been applied to near-eye displays in various aspects to overcome the limitations of conventional optics. The wavefront reconstruction capability of holographic techniques has been extensively exploited to develop optical see-through 3D holographic near-eye displays of glass-like form factors. In this article, the application of holographic techniques to AR and VR near-eye displays is reviewed. Various applications are introduced, such as static holographic optical components and dynamic holographic display devices. Current issues and recent progress are also reviewed, providing a comprehensive overview of holographic techniques that are applied to AR and VR near-eye displays.

Central Zone Size Dependence of Peripheral Dimming Technique Under Wide Field of View Environment

Peripheral dimming technique based on gaze tracking was proposed to reduce the power consumption of emissive displays adopted in headset. This technique divides an image into two zones: a central zone which is a circular area centered on the gaze point, and a peripheral zone which is the outer area of the central zone. This technique achieves power savings by gradually reducing the brightness in the peripheral zone while maintaining the brightness of the central zone. This paper investigates effects of central zone size (CZS) on the technique under a wide field of view (FoV) environment. Psychophysical experiments are conducted to determine the threshold dimming conditions for the CZSs of 10°, 25°, and 40°. The results showed that the individual variations and the mean value of threshold dimming condition increased in proportion to CZS. Interestingly, in contrast, the power-saving efficiency depending on the CZS was not significantly different. The technique can reduce power consumption of display panel by approximately 12% on average, up to 15%. It is demonstrated that the technique is feasible even in a wide FoV environment, and the CZS can be flexibly determined depending on the application or image content.

PixelEngineTM All-in-One: a Printable Pixel-Driver MicroIC with Three-Dimensionally Integrated Red, Green, and Blue MicroLEDs

Displays that utilize millions of tiny microLEDs promise a future generation of phones, computers and televisions that are bright enough for sunlit environments yet consume less power. The microLEDs are made using wafer-level semiconductor processes, and key to manufacturing displays is the capability to assemble billions of microLEDs onto panels. Elastomer stamp transfer printing is a mass transfer technology with the yield, accuracy, speed, and scalability required to meet the demands of display manufacturing. The versatility of elastomer stamp transfer leads to further innovations for displays, these include the ability to integrate miniature integrated circuits, called microICs, for advanced backplanes and strategies where microLEDs are combined into PixelEngine packages on intermediate substrates before final assembly to the display panel. This paper reviews how transfer printing has been applied to microLED display development to date and describes a pixel-driver microIC with vertically integrated microLEDs, called PixelEngineAll-in-One, that performs all pixel functions and is designed to enable displays realized through assembly onto passive wiring panels.

Screen-Overprinted Perovskite RGB Microdisk Arrays Based on Wet-Solute-Chemical Dynamics for Full-Color Laser Displays.

Owing to outstanding optoelectronic properties, halide perovskites are great candidates for novel laser display applications. However, the realization of their practical flat-panel display applications is challenging because of the incapacity to controllably assemble different halide perovskite microlaser arrays onto an identical substrate as pixelated full-color panels due to intrinsic fragile crystal lattices. Here, perovskite red-green-blue (RGB) microdisk arrays are reported, acting as flat-panels for full-color laser displays. A universal screen-overprinting technology is developed to integrate full-color perovskite microdisk arrays on a prepatterned template, which is on the basis of wet-solute-chemical dynamics involving a combination of surface tailoring and solvent selection. Via such an overprinting method, perovskite RGB microlaser matrices with precise localizations and well-defined dimensions were fabricated on an identical substrate, and each set of RGB microlaser served as a pixel for full-color display panels. On this basis, static and dynamic laser displays have been demonstrated with as-prepared full-color panels. These results will provide novel design concepts and device structures for future full-color laser display applications.

Achieving Bright Reddish-Orange Luminescence in CaSnO3 Ceramics through Doping Manipulation

The reddish-orange phosphors of rare-earth activator have attracted intense interest due to their applications in lighting and display devices, including plasma display panel, field emission display and white light diode. In this work, Eu-doped CaSnO3 phosphor materials were prepared and examined. Their X-ray diffraction patterns were used for lattice parameters calculations and show that there was no phase transformation in all doping conditions. XANES studies suggest the stabilization of Sn and Eu ions in 4+ and 3+ oxidation states in the prepared phosphors, respectively. A broad emission band, with a major peak at 614 nm upon excitation wavelength of 395 nm, was observed in the range of 550 to 730 nm at room temperature due to 5D0 → 7FJ transition of Eu3+ ions. The luminescent spectra of the samples showed the intense light emission in the red-orange light region.