Session Index

Making use of the advance of OLED technologies and characteristics of OLEDs, we explore and discuss the possible uses of curved and three-dimensional structures for manipulating or enhancing optical performance of OLEDs, such as light extraction, emission distribution etc.

 

In this work, we demonstrated a deep-red emission organic light-emitting diode (OLED), which showed high brightness, low operational voltage, and low-efficiency roll-off. The deep-red emission OLED can be employed in photobiomodulation therapy (PBMT), such as wound healing, hair growing, and skin rejuvenation.

 

This work reports the adoption of high index transparent electrode as a new avenue for greatly boosting OLED efficiency. By using the Nb-doped TiO2 electrodes with a high refractive index of 2.4, along with high-performance organic materials, a high EQE of 41.5% is realized for conventional planar OLEDs.

 

This work presents an active-matrix organic light-emitting diode (AMOLED) pixel circuit for 15 Hz frame rate display applications. Simulation results show that the relative current error rates are less than 4%. Moreover, the OLED emission current fluctuations during the 66.6 ms emission period have significant improvements.

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A flexible differential amplifier comprising 8 a-IGZO TFTs is demonstrated on polyimide substrates. It exhibits a gain of 11.6 dB, cut-off frequency of 620 Hz and CMRR of 15.3 dB. Furthermore, similar performance is observed when the flexible amplifier is inwardly and outwardly bent to a radius of 1 cm.

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MicroLED display is considered to be the next generation display technology due to its high brightness, wide color gamut, high aperture ratio, and good reliability. In additional to conventional display applications, MicroLED display can also be used for innovative display applications such as transparent and flexible display. Based on our proprietary PixeLED® display technology and SMAR·TechTM repair solution, we have demonstrated various new applications, such as borderless transparent display, ultra-high brightness wearable device, and ultra-thin flexible display.

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The passive-matrix μ-LED display with a pixel size of 20×20 μm2 was achieved by using a maskless laser direct writing technique. This system can not only reduce the glass-mask usage but shorten the development time. The illuminance of blue passive-matrix μ-LED display was achieved 516 cd/m2 at 3 V.

 

In this study, we demonstrate a 3-in-1 mini-LED with 160 x 65µm sub-pixel chip size. The deposition of QD layer by using inkjet printing technique achieved a full-color display. Moreover, the use of the atomic layer deposition avoids the oxidation and steam, maintain the color purity of red and green.

 

In this work, we fabricate MAPbBr3 perovskite with our innovative sandwich evaporation technique (SET) to form green light emitting diodes with better perovskite crystalline property. Our home-made chamber can be vacuumed with common rotary pump. This technique features with low vacuum and low cost approaches.

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Micro-LED of small pixel sizes is very challenging. Here we explore a simple and low-cost approach using exposure, development and etching to produce high efficiency non-rare-earth-element fluorescent arrays without the necessity of mass transfer. We have achieved pixel sizes of 60*20 μm and 6*2 μm fluorescent arrays.

 

Van der Waals epitaxial growth of BiI3 was demonstrated with a great potential in flexible resistive switching device with simple fabrication process and multistate data-storage capability. The devices with the copper foil/h-BN/BiI3/Au structure exhibited forming-free nature, high on/off ratio(>107), excellent data-retention(>104s), high voltage sweep endurance, and superior bending endurance.

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CdSe/CdS/ZnSe with ZnS/ZnO core-shell quantum dots were synthesized with various oleamine contents in the wavelength of 505-610 nm. The photoluminescence intensity of quantum dots with ZnO shell showed a relatively slow decay of 9.8% under 85°C/85% RH aging test for 500 hours, indicating good stability in resisting the long-term oxidation.

 

In this report, we present a method how to quantitatively analyze and simulate the image distortion and the brightness reduction effect with cylindrical shell concave and convex structure. Also, we propose an effective method to re-construct a corrected image for curved OLED displays.

 

Screen burn induced by long time static patterns or images seriously degrades the image quality of OLED TVs. In this work, we developed a two-step algorithm to automatically detect and track those burn-in occurrence regions. Proposed algorithm successfully detects specific patterns with high computational efficiency based on Mask R-CNN model.

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This research would be focusing on solving narrow-frame display’s bright line issue, to meet the car manufacturer’s need. The experimental results show that the bright line situation could be improved by improving the process of production, matching the appropriate optical film, and designing the optical part of light guide plate.

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In this article, a transparent liquid crystal display made of polymer network twisted nematic liquid crystals (PNTNLC) and polarizers is used, which can light up the image and blur the background in one area at the same time, and improve the problem of image quality degradation caused by background interference.

 

The difference of polar anchoring properties such as anchoring energy and pretilt angle of liquid crystal cell under different UV irradiance strength in photoalignment process are presented. In this work, vertical alignment nematic liquid crystal cell with commercial photoalignment polyimide film is used.

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High-efficiency blue triplet-triplet fusion fluorescence organic light-emitting diode was demonstrated with external quantum efficiency of 9.4% and CIE coordinates of (0.14, 0.17).

 

Iridium(III) complexes 1 and 2 were employed as representative dopant in fabrication of blue PhOLED devices. The OLED devices gave turn-on voltage of 4.3 and 4.3 V, max. EQE 16.3 and 12.2 %, power efficiencies of 17.6 and 10.4 lmW‒1 and CIEx,y coordinates of (0.16, 0.26) and (0.16, 0.20).

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Three donor-acceptor molecules consisting of dicyano-imidazole and phenylcarbazole were synthesized and applied to the host materials. Combined the balanced carrier mobility with the proper device designs in this study, the efficiency roll-off under high luminance can be greatly reduced, and the practicality of the resulting OLEDs can be significantly improved.

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In this report, a novel host material for blue phosphorescent organic light-emitting diode (OLED) was demonstrated with maximum external quantum efficiency (EQE) of 17.92 %, current efficiency of 42.5 cd/ A and power efficiency of 44.5 lm/ W.

 

In this research, deep blue organic light emitting diode based on hydroxynaphthyridineDerived Group III metal chelates, AlmmND3, as non-doped emitting layer (EML) was demonstrated. By optimizing the thicknesses of EML, maximum external quantum efficiency (EQE) reached 1.92% for 30 nm of EML with CIE coordinates of (0.15, 0.07).

 

Improving the device performance of green phosphorescent organic light-emitting diodes (OLEDs) has been realized by employing the charge generation layer (CGL) to connect two light-emitting units. The remarkable results show that the external quantum efficiency and current efficiency of the tandem structure are two times of the reference device.

 

Three donor-acceptor molecules consisting of dicyano-imidazole and phenylcarbazole were synthesized and applied to the host materials. Combined the balanced carrier mobility with the proper device designs in this study, the efficiency roll-off under high luminance can be greatly reduced, and the practicality of the resulting OLEDs can be significantly improved.

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In this report, a new near-infrared (NIR) emitter has been applied to the NIR phosphorescent organic light-emitting diodes (PhOLED), which showed peak emission of electroluminescence at 682 nm and exhibited the device efficiency with a maximum external quantum efficiency of 4.81%.

 

Preparation for OLEDs is time-consuming, this study brings up a fast-screening method for exciplex by measuring photoluminescence spectra in a comparatively high polar solvent. Exciplex was further confirmed by phosphorescence as well as transient photoluminescence decay. The results indicate that this method could promote the rapid development of exciplex research.

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Two bipolar host materials including ImM-s-Cz and ImM-mCP were proposed for realizing high-performance OLEDs. The two synthesized compounds possess balanced electron/hole transport capability, which can help expand the recombination region and thereby reduce triplet-triplet annihilation. The results demonstrate that the devices can achieve high efficiency in a high luminance range.

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Pt(II) complex K416 was dopant in fabrication of OLED devices with varied doping ratio, with 1 wt.% of K416 in SimCP host exhibited max. EQE of 5.8% and CIEx,y coordinates of 0.20, 0.31. In contrast, 100 wt.% of K416 achieved max. EQE of 26.8% and CIEx,y coordinates of 0.41, 0.55.



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A fluorescent film is formed using the solution and spin-coating method. The thickness of the film is only around 10 μm with its QY more than 80%. Based on FTIR measurement, comparison of resonance of functional group with the QY reveals that the lower the displacement, the higher the QY.

 

In recent years, displays are constantly seeking new breakthroughs, pursuing better resolution or more vivid colors for 3C product, even applications in VR/AR. In this work, we developed 64×32 inline structure Micro-LED array display by various bonding methods combined with glass circuit connecting passive matrix IC drive.

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a-IGZO TFTs with gate electrodes monolithically integrated with wireless rectifier circuits are demonstrated. The wireless rectifier circuit is composed of a coil, a Ni/a-IGZO Schottky diode and two capacitors. The output voltage of the wireless rectifier circuit and electrical performance of the a-IGZO TFT with wireless power supply are investigated.

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Al/Hf co-doped ZnO nanolaminates are grown by atomic layer deposition. Thin film transistor of Al/Hf co-doped ZnO with thickness ratio of 1:10 exhibits excellent performance with field effect mobility of 3.6 cm^2/Vs, On/Off ratio of over 10^6 and subthreshold swing of 2.97 V/decade.

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We report on a single-exposure photo-alignment using a spatial light modulator (SLM) which is able to provide spatially variant two-dimensional modulation of a light beam and a QWP. The combination of the SLM and the QWP enables arbitrary patterned alignments of LC molecules realized by single exposure.

 

In previous work, we have demonstrate that using repetitively applied field (RAF) to reconfigure blue-phase liquid crystals into stable orthorhombic and tetragonal lattices. In this work, we use the same approach applied in different thickness of BPLC, then we discuss the lattice distortion and observe efficient electro-optic response after polymer-stabilized.

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Applying a continuous field to the blue phase will generate a large heat accumulation, which will concentrate the BP lattice and make the non-cubic lattice unstable. The RAF technology can be used between field and field that has enough time to dissipate the heating, making the stable stretched non-cubic lattice.

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The characteristic of plasmonic random lasers (PRLs) from dye-doped liquid crystals inside the PCFs without and with addition of silver nanoparticles (AgNPs) have been invesitgiated. Through pump energy increased, the intense light scattering as well as the increase in output intensity of RLs were obvious with the addition of AgNPs.

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This work proposes a simple photo-alignment exposure system for fabricating liquid crystal Pancharatnam-Berry phase optical elements (LCPBOEs) by using a LCPBOE that satisfies half-wave condition as a mask. A polarization grating, which is a kind of LCPBOEs, was successfully demonstrated to prove our concept and characterized.

 

An approach to narrow the bandwidth of a light source is proposed. The chiral azobenzene-doped cholesteric liquid crystal (CAdCLC) cell is divided into two regions having two different pitch lengths. The wideband light source becomes a narrow one if it travels through two regions of the CAdCLCs cell.

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We prepare that by incorporating trioctylphosphine oxide capping ligand into the oleic acid/oleylamine system, CsPbBr1.2I1.8 quantum dots with excellent optoelectronic properties can be achieved. When the morphology of the QDs film with aqueous lead nitrate was modified during coating, a maximum luminosity of 502.7 cd/m2 was achieved for the QDLEDs.

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Fluorescent dyes are combined with the film-forming polymer in the solvent to form a fluorescent solution. Its quantum yield is 92.3 %. We use the self-made high-efficiency fluorescent solution to deposit on substrates to form a fluorescent film, which can maintain its luminous properties without being encapsulated in the atmosphere.

 

In this paper, we adopted a transparent display to develop an interactive system, and apply it in an entertainment field. The interactive system has three main technologies: eye tracking, object identification, and coordinate transformation. By integrating those technologies and high transmittance of the panel, we develop a novel interaction system.

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This is a set of methods used on transparent displays to use tags to locate objects behind, and to make the three-dimensional images on the transparent display plane rotate and move according to the tag to make corresponding changes.

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This paper will introduce a display design that combines a stress matching layer with a transparent Micro LED display. This design can simultaneously make the display have high-intensity stress characteristics and low light loss.

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In order to improve the transmittance and background visibility of the transparent micro LED, through proper pixel design and arrangement, we propose an anti-diffraction structure of 7.65 inches and 57 PPI, so the intensity of the diffraction pattern is less than 1%.

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This is a three-dimensional deformable substrate using engraving technology. The deformable substrate must use stretchable conductive materials. The resistive and capacitive components of wearable devices can be manufactured by using this technology.

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A simulation platform for rotational display systems including all-around and swept volumetric displays is proposed. This platform enables system designers to predict spatial and temporal image quality of various system parameters for optimizing the system performance.

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In the study, a prediction model of visual comfort is proposed based on an artificial neural network. Using the ambient illuminance levels and screen parameters as features, the model can well represent the visual perception with high correlation coefficients.

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Camera spectral sensitivity estimation based on quadratic programming with Tikhonov regularization is studied. The Lagrange multiplier of this method was usually determined with L-corner in literatures. We found that response errors of estimated spectral sensitivity can be effectively reduced by the use of validation samples to determine the Lagrange multiplier.

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This investigation reports observations of deformation behavior in liquid crystal elastomer (LCE) films that are thermos-responsive materials. The deformation of the LCE films that originates from the difference in coefficient of the thermal expansion between top and bottom surfaces can be changed by heat and restored by heat removal.

 

This paper introduces three different substrates. If the ITRI standard 45U PI substrate is used, the transmittance is about 67%; if the glass substrate or high-temperature transparent T89 PI substrate is used as the substrate, the transmittance can be close to 80%.

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The angular color variation of RGB micro-LED with correlated color temperature (CCT) at 6500K is investigated. The model is developed the RGB micro-LED devices, the color variations are analyzed. The measurement of angular color variation of the RGB micro-LED sample is conducted validate the simulation model and obtain good agreement.

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This study reports a full-color u-LED array with high color stability which combined (20-21) semi-polar blue LED substrates and quantum dot photoresist color-conversion layer(QDPR) with a chip size of 50 um in diameter. RGB pixel showed few color shifts when high current density injected and achieved 114.4%NTSC and 85.4% Rec.2020.

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A hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) gate driver with Vth shift compensation for high reliability 14.1-inch automotive display has been proposed. For using Vth shift compensation structure, degradation at normal and high temperature environment of driving TFT and noise-free block could be compensated.

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To enhance view quality of transparent AMOLED, substrate was importance part. The panel’s transmittance were improved by increasing substrate’s transparency. Transparent polyimide was difficultly used for AMOLED’s substrate because of its thermal stability. We verify several PI’s characteristics, as a result, the prototype of high transparent AMOLED was produced.

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A high efficiency of green quantum dot light emitting diode with current efficiency of 58.1 cd/A and external quantum efficiency of 16 % was demonstrated. Compared to reference device, there is 2.6x improvement, and which is originated from better hole injection to QD layer and carrier balance within QLED

 

High-quality perovskite CsPbBr3 quantum dots (QDs-CsPbBr3) doped with pure natural aloe vera material were prepared using hot-injection method. The photoluminescence of aloe vera:QDs-CsPbBr3 was characterized by excitation wavelength of 522 nm, with narrow line-width emission of 20.8 nm. The QDLEDs exhibits a maximum luminance of 3161 cd/m2.

 

We propose a novel method to control the pretilt angles of liquid crystal (LC) molecules by doping with a gelator and using planar alignment layers coated on the substrates. Spontaneous vertical alignment of gelator was combined with the planar alignment layer to achieve 7–84° pretilt angles of the LCs.

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We apply an in-plane electric field on cholesteric liquid crystals (CLCs) to produce a uniform lying helix (ULH) structure. The ULH alignment was cured by the polymer to form a stable structure. The flexoelectro-optic effect was demonstrated by measuring an in-plane rotation of helical axis in ULH CLCs.

 

We investigate the difference between VA-FFS LC mode employing LC materials with positive and negative dielectric anisotropy. New 3D electrode design was found to help improve potential response speed, transmission and stability. Due to its fast sub-millisecond response, VA-FFS LC has been actively developed for VR/AR in recent years.

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We propose a vertically aligned (VA) liquid crystal cell with three-terminal electrode structure and simulate the relationship between response time and electrode structure. Simulation results predict the VA LC with three-terminal electrodes exhibits faster response than that with conventional electrodes. Experimental results confirm simulation predictions.

 

In this study, we propose a multi-angle director model to simulate the optoelectronic characteristics of a polymer-dispersed liquid crystal (PS-BPLC). We performed simulations based on the director model and calculated BPLC cell with a weighting for each angle. The model calculated results are in good agreement with the experimental data.

 

To extend the lifetime of blue PhOLED, a triplet exciton sharing layer was placed near the main recombination layer of emitting layer inside PhOLED. A green emitter was employed as energy transfer from blue emitter to prevent the triplet-polaron annihilation and triplet-triplet annihilation, leading to the enlarged device lifetime.

 

New TADF-type exciplex host with two different electron transport layers, DPPS and TPBi, were demonstrated. The optimums device shows the external quantum efficiency of 3.64%, the driving voltage of 5.2V, the luminance of 3971 cd/m2 at 6V, and CIE coordinates of (0.328, 0.569) and less carrier spike in TrEL.

 

The organic emitting materials were synthesized, with carbazole phenol-containing derivatives as host, and anthracene fluorine-containing derivative as guest. They all owned well thermal stability and steric effect. In the component test, they were used as the light-emitting layer by evaporation and demonstrated good performances.

 

The carrier transport properites of three donor-acceptor molecules incorporating both dicyano-imidazole and carbazole moieties, namely imM-o-Cz, imM-m-Cz, and imM-p-Cz by time-of-flight measurement. imM-m-Cz exhibited one of the most balanced carrier mobility in the reported literature, confirming that the molecule has a balanced bipolar nature.

 

OLEDs fabricated on an intentionally cracked ITO electrode have shown improved efficiency at a high electrical stress. The improved OLED characteristics are attributed to crack-free surface of the intentionally cracked ITO. In addition, high mechanical flexibility of intentionally cracked ITO has shown its high potential for flexible OLED applications.

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In this study, a liquid crystal lens as a template during holographic exposure processes was investigated and demonstrated to fabricate HOEs as lenses.The experimental results show optical comparisons of generated Fresnel zones of completed HOEs via both templates of conventional glass lens and liquid crystal lens during fabrication processes, respectively.

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