bluuebunny/crossref_metadata_2025 huggingface dataset:
Teaching Beginners to Decode Consonant–Vowel Syllables Using Grapheme–Phoneme Subunits Facilitates Reading and Spelling as Compared With Teaching Whole‐Syllable Decoding
Authors: Sargiani Renan de Almeida , Ehri Linnea C. , Maluf Maria Regina
Published: June 2021

In this experiment, we examined whether beginning readers benefit more from grapheme–phoneme decoding (GPD) than from whole‐syllable decoding (WSD) instruction in learning to read and write words. Sixty Brazilian Portuguese‐speaking first graders (M age = 6 years 1 month) who knew letter names but could not read or write words were randomly assigned to one of three conditions. The GPD group was taught to decode 40 consonant–vowel (CV) syllables by sounding out and blending grapheme–phoneme constituents (combinations of 10 consonants and five vowels). The WSD group was taught to decode the same CV syllables as whole graphosyllabic units. The individual grapheme–phoneme (IGP) group was taught the same 15 grapheme–phonemes as single units but no decoding. Groups were taught to a mastery criterion. Results showed that GPD instruction was much more effective than WSD and IGP instruction in enabling beginners to read CV syllables, multisyllabic words, and pseudowords; to learn to read words from memory; to write words; and to segment and blend spoken words phonemically. Also, GPD instruction facilitated phonological memory for spoken pseudowords. Despite receiving much practice in reading whole CV syllables, the WSD group learned few, if any, grapheme–phoneme subunits. Results support theories that reading instruction is most effective when it begins by teaching students to decode with small grapheme–phoneme units rather than with larger syllabic units, even when syllables are salient spoken and written units in the writing system.
Regional evaluation of satellite‐based methods for identifying end of vegetation growing season
Authors: Shen Ruoque , Lu Haibo , Yuan Wenping , Chen Xiuzhi , He Bin
Published: June 2021

Autumn phenology plays an important role in regulating ecosystem carbon and water cycling, but it has received less attention than spring phenology. Satellite‐based methods have been widely applied in monitoring autumn phenology at large spatial scales. However, few studies have evaluated and compared the performance of different satellite‐based methods in autumn phenology identification. Here, we compared the spatiotemporal variations of end of vegetation growing season dates (EOS) as determined from eight prevailing satellite‐based methods against long‐term field observations at 31 sites in China. We found that field‐based observations in forest and grassland sites, respectively, had rates of EOS delay of 2.11 and 3.85 days per 1°C increase in mean annual temperature (MAT) during 2001–2014. However, nearly all the eight satellite‐based methods underestimated these delay rates compared with the ground observations over all sites. We also found that the eight methods weakly agreed with the field‐observed interannual variations of EOS. At the regional scale, the identified average EOS differed up to 38 and 40 days among the investigated satellite‐based methods in forest and grassland ecosystems respectively. The delayed rate of identified EOS with the increase of MAT ranged from 0.77 to 3.51 days °C−1 for forests and from 0.41 to 2.95 days °C−1 for grasslands. The identified EOS by most of the eight methods had delayed temporal trends in forests during 2001–2014 while we found advanced trends in grassland ecosystems. The large discrepancy in EOS identification among the prevailing satellite‐based methods highlight the need for more accurate satellite‐based methods in data gap‐filling and phenometrics detection, and more extensive, multi‐species based field observations that can be used to constrain and validate the satellite‐based methods.
4‐1:Invited Paper:Highly Robust Flexible IGZO TFTs and Integrated Circuits
Authors: Kim Kyung-Tae , Kang Seung-Han , Cho Sung-Soo , Park Hun-Bum , Jo Jeong-Wan , Park Sung Kyu
Published: June 2021

We investigated amorphous metal‐oxide semiconductor based electronics for flexible and stretchable applications. In particular, we demonstrated a‐IGZO and SWCNT hybrid flexible amplifiers on PI substrate. Also, mesa structured a‐IGZO TFTs showed stable electrical operation under 125 μm bending radius up to 10000 cycles, enabling ultra‐flexible 7‐stage ring oscillator circuit.
4‐3: Distinguished Paper: IGZO TFT Arrays for Biometrics‐Under‐Display and Biomedical Applications
Authors: Kronemeijer Auke Jisk , de Haas Gerard , Verbeek Roy , Bel Thijs , van de Laar Robert , Ugalde-Lopez Leslye , Gelinck Gerwin
Published: June 2021

This paper presents a monolithic manufacturing process to realize active‐matrix meshed TFT arrays on foil with physical voids between pixels, realizing membrane‐like structures for use in biometrics‐under‐display applications. Moreover, however, the concept enables new applications in the biomedical electronics domain.
5‐2: Enhanced Bending Endurance with Transverse Tensile Strain and 4‐Terminal Double Gate LTPS TFTs for flexible AMOLED
Authors: Lee Jaeseob , Lee Yongsu , Kang Taewook , Chu Hyeyong , Lee Changhee , Kwag Jinoh
Published: June 2021

This letter investigates the degradation behavior of p‐channel LTPS TFTs on PI substrate under the static bending stress. During 1hr bend, the threshold voltage shifts positively and the subthreshold slope increases slightly. In transverse compressive strain, the field effect mobility increases abruptly with the decrease of the effective channel length and the off state leakage current. This is attributed to the generation of the strain‐induced GI defects near the source and drain terminals, resulting in the trapping of electrons and a shrinkage of the effective channel length and the H passivation of the strained Si bonds in the channel. By inserting the bottom metal layer to block the H diffusion from PI substrate, the controllable normal NBTI behavior is observed in a strained LTPS TFT on PI. These transverse tensile strained and 4‐termianl double gate LTPS TFTs on PI shows as a stable switching TFTs on PI for the flexible system‐on‐panel display.
5‐3: Experimental and Physics‐Based Analysis of Leakage Currents for LTPS TFTs in AMOLED Displays
Authors: Kim Keunwoo , Kim Hanbit , Chu Jaehwan , Thanh Tien Nguyen , Lee Jaeseob , Lee Dokyeong , Kang Meejae , Kim Doona , Kim Sangsub , Sung Bummo , Kwak Hyena , Lee Yongsu , Kang Taewook , Chu Hyeyong , Lee Changhee , Kwag Jinoh
Published: June 2021

This paper presents extremely‐low leakage technologies in low‐temperature polysilicon (LTPS) TFTs. Experimental and physics‐based analysis of leakage currents, emphasizing the effects of process technologies and device design, are described. Small‐geometry TFTs, controlled by optimal LTPS process, dramatically reduce off‐state leakage current (Ioff) by suppressing gate‐induced drain leakage (GIDL) and thermal generation currents, thus potentially offering lower frame rate operations by reducing IC clock power. Numerical device simulations, supplemented by physics‐based analysis, are performed to corroborate the remarkable low‐Ioff experimental results as well as more‐than‐twice enhanced on‐state current (Ion) in optimized LTPS devices.
6‐2: Invited Paper: An Imager with Organic Photodetectors Based on LTPS‐TFT Technology
Authors: Nakamura Takashi , Kato Hirofumi , Kitamura Ayato , Kimura Hiroyuki , Takimoto Akio , Yokota Tomoyuki , Someya Takao
Published: June 2021

We have developed a high‐resolution 508 ppi conformable imager using low‐temperature polysilicon thin‐film transistors (LTPS TFTs) on a plastic substrate together with organic photodetectors which has high sensitivity in wavelength of visible and near‐infrared regions (NIR). Using a NIR light source, both images of fingerprints/veins and pulse waves are successfully obtained. By adding red light source, both red pulse wave and NIR pulse are measured to calculate percutaneous oxygen saturation.
6‐3: Fingerprint‐on‐Display Module Based on Organic Optical Sensors for 1‐to‐4‐Finger Authentication in Next‐Generation Smartphones
Authors: Flamein François , Bouthinon Benjamin , Joimel Jérôme
Published: June 2021

Fingerprint on Display (FoD) Modules based on organic photodetectors have been realized and have achieved high performances for integration within smartphones. Such modules allow full display size enabling multiple fingers authentication at once and increasing security level.
6‐4: Organic Optical Sensor Based on a‐Si TFT Backplane Used in Fingerprint Identification under OLED Display
Authors: Zhou Lin , Qi Chaoyang , Cheng Jin , Wang Ruichao , Kong Dexi , BARBOT Anthony , JOIMEL Jérôme , Zhong Kunjing , Li Cheng , Che Chuncheng
Published: June 2021

The solution‐processed organic optical sensors based on a‐Si TFT backplane have been realized, which indicate the comparable performance compared to a‐Si photodiode optical sensors. Furthermore, the organic sensors demonstrate an extremely low absolute sensitivity threshold (also known as Noise Equivalent Power, NEP), which is down to 2.1 nW/cm2 at 530nm.
7‐1: Distinguished Paper: Reliability Improvement of IGZO‐TFT in Hybrid Process with LTPS
Authors: Aman Mehadi , Takeda Yujiro , Ito Kazuatsu , Yamamoto Kaoru , Tanaka Kohei , Matsukizono Hiroshi , Nakamura Wataru , Makita Naoki
Published: June 2021

An AMOLED panel using hybrid backplane technology based on p‐type LTPS and n‐type oxide has been successfully manufactured. New pixel and Gate‐on‐Array (GOA) circuits were designed and fabricated using this technology. CMOS operation of the GOA is realized by utilizing both IGZO and p‐LTPS. The hybrid backplane AMOLED panel can operate between 1 Hz and 120 Hz, which enables both high refresh rate and low standby power display applications. Furthermore, the AMOLED panel lifetime has markedly enhanced by improving IGZO TFT's uniformity and reliability.
7‐4: High Mobility Hydrogenated Polycrystalline In‐Ga‐O (IGO:H) Thin‐Film Transistors formed by Solid Phase Crystallization
Authors: Furuta Mamoru , Shimpo Kenta , Kataoka Taiki , Tanaka Daiki , Matsumura Toshihiro , Magari Yusaku , Velichko Rostislav , Sasaki Daichi , Kawashima Emi , Tsuruma Yuki
Published: June 2021

Hydrogenated polycrystalline In‐Ga‐O (IGO:H) thin‐film transistor (TFT) was demonstrated by low‐temperature solid phase crystallization (SPC). The amorphous IGO:H was deposited by H2 doping during RF magnetron sputtering in Ar and O2 atmosphere. An intentionally doped H2 in IGO:H film suppressed the crystallization during the film deposition. The amorphous IGO:H film could be converted into the poly‐IGO:H film by SPC below 250 °C. A maximum field effect mobility of 50.6 cm2/Vs was obtained from the SPC poly‐IGO:H TFT. The polycrystalline oxide semiconductors (OSs) are simple and cost‐effective approach to achieve high‐performance OS TFTs for future displays.
8‐2: Low Cost Manufacturing of AlZnO/ZnO Thin Film Transistor with High Mobility Over 80 cm2/Vs and Positive Threshold Voltage by Spray Pyrolysis
Authors: Saha Jewel Kumer , Ali Arqum , Islam Md Mobaidul , Bukke Ravindra Naik , Jang Jin
Published: June 2021

We demonstrate the low‐cost AlZnO/ZnO TFT by spray pyrolysis at 350 °C. High field‐effect mobility is achieved over 80 cm2/V.s with a subthreshold slope of 123 mV/decade. The higher mobility is due to the 2D like electron gas at the interface of AlZnO/ZnO. The stack TFT shows positive threshold voltage and negligible threshold voltage shift under positive bias stress. The presence of Al‐O at the interface reduces the oxygen vacancies and improves the bias stability.
8‐5: Invited Paper: P‐Type Oxide Semiconductors for Displays: Material Design and Field‐Effect Devices
Authors: Shi Jueli , Yang Zhenni , Zhang Kelvin Hongliang
Published: June 2021

Oxide thin film transistors (TFTs) represented by n‐type amorphous InGaZnOx (a‐IGZO) have revolutionized the display industry. However, the lack of p‐type counterparts hinders the development of high‐resolution displays with lower energy consumption. In this paper, we review the recent trend in the material design and devices of p‐type oxide semiconductors.
10‐3: The Electrical Connection of In‐cell Touch between Two Individual Substrates in 5.6‐inch Flexible AMOLED Displays
Authors: Ho Shu-Te , Shih Ching-Yao , Wang Cheng-Liang , Lin Kung-Cheng , Fang Chiao-Wen , Kuo Wei-Ting , Yu Ming-Hsuan , Huang Shih-Hsuan , Tsai Yi-Wei , Wu Chang-Chan , Ko Chien-Ming , Ou Yi-Fu , Yu Chih-Yu , Lee Wen-Hui , Wang Wan-Tsang
Published: June 2021

A 5.6‐inch foldable AMOLED panel and an in‐cell touch sensor built up on a symmetrical stacking structure from separate flexible substrates has been demonstrated. To simplify the configuration of outer lead bonding, a key electrical transfer of touch signal to an opposite substrate along z‐axis direction is by using conducting beads. The observations of conducting beads, electrical measurements, resistance calculations and failure model analysis have been reported in this paper.
12‐2: Photo‐Patternable Organic Materials for Display
Authors: Sugawara Ryutaro , Sato Azumi , Ikuma Naohiko , Aoki Tomosaburo , Yamanouchi Atsushi , Shiota Dai
Published: June 2021

The rapid development of display materials has led to the increasing exploration of high performance materials, especially those with high refractive index and low reflectance. Moreover, photo‐patternable materials are required to simplify the process. To meet such demand, we have developed photo‐patternable high refractive index material and low‐temperature‐curable black matrix.
13‐2: A Novel Compensation Algorithm for First Frame‐Drop on AMOLED
Authors: Su Shang-Yu , Lin Xuan-Yong , Pai Feng-Ting
Published: June 2021

In this paper we present a novel algorithm for compensating OLED luminance drop at first frame. It is due to the unexpected residual voltage from previous frame and IR‐drop of ELVDD power. Our method without complex TFT driving circuits so that the proposed algorithm is easily implemented to driver IC for different panels. Experimental results show that this algorithm enhances the luminance at first frame and reducing temporary image sticking issue.
13‐3: Invited Paper: Video Frame Interpolation via Structure Motion based Iterative Feature Fusion
Authors: Li Xi , Cao Meng , Tang Yingying , Johnston Scott , Hong Zhendong , Ma Huimin , Shan Jiulong
Published: June 2021

Video Frame Interpolation synthesizes non‐existent images between adjacent frames, with the aim of providing a smooth and consistent visual experience. Two approaches for solving this challenging task are optical flow based and kernel‐based methods. In existing works, optical flow based methods can provide accurate point‐to‐point motion description, however, they lack constraints on object structure. On the contrary, kernel‐based methods focus on structural alignment, which relies on semantic and apparent features, but tends to blur results. Based on these observations, we propose a structure‐motion based iterative fusion method. The framework is an end‐to‐end learnable structure with two stages. First, interpolated frames are synthesized by structure‐based and motion‐based learning branches respectively, then, an iterative refinement module is established via spatial and temporal feature integration. Inspired by the observation that audiences have different visual preferences on foreground and background objects, we for the first time propose to use saliency masks in the evaluation processes of the task of video frame interpolation. Experimental results on three typical benchmarks show that the proposed method achieves superior performance on all evaluation metrics over the state‐of‐the‐art methods, even when our models are trained with only one‐tenth of the data other methods use.
16‐3: A Visualization Method of Training Data Completeness in Array Defect Recognition Based on Deep Learning
Authors: Guo Kai , Qin Wei , Li Xiaolong , Liu Weixing , Xu Zhiqiang , Teng Wanpeng , Wang Tieshi , Zhang Chunfang , Zhou Feihu , Peng Kuanjun , Chen Xiaochuan , Yuan Guangcai
Published: June 2021

Feature visualization engineering of convolutional neural network is a basic research project in deep learning. The working principle of network, the image features extracted from network and classification basis of images can be revealed, by visualization the extracted features. In this paper, the de‐convolution and CAM method are used to visualize array defect features extracted by CNN. We find that the low‐layer network of CNN is unselective, and its main function is to separate all objects in the picture from their background, this is why the low‐layer networks’ parameters usually do not been trained in transfer learning. Instead, the selectivity is slowly emerging in high‐layer networks and only the object features related to classification are preserved. At the same time, we find that the classification of array defects is not only related to itself, but also to its background, this can also explain why array defect classification is more difficult. On the other hand, this paper verifies the importance of array defect attributes in defect classification by counting the accuracy of network identification after modified the defect attributes, and a defect recognition disturbance rate index was defined to quantify the dependence of defect classification results on its attributes. Finally, the images edited by defect attributes with high disturbance rate are added to the training set, and the defect recognition accuracy is improved by 3% ~ 5%. This method can be used to judge the importance of each array defect attribute, find out the crucial attributes and pinpoint the completeness of training data in CNN classification. At the same time, it can explain the classification principle of CNN and provide necessary guidance and help for attribute image collection and CNN classification accuracy improvement.
16‐4: Invited Paper: Region‐Based Machine Learning for OLED Mura Defects Detection
Authors: Lee Janghwan
Published: June 2021

Automatic inspection of Mura defects is a challenging task in display manufacturing. Due to the nature of Mura defects, which appear as brightness variances in the low‐contrast images captured by the optical inspection camera, the defects are extremely difficult to detect because they show no clear edges from their surroundings while the image backgrounds usually present uneven illumination. In this paper, I propose an effective way to detect two types of Mura defects using a region‐based machine learning approach. My research includes three components: 1) creating a quality dataset from the raw optical inspection images, 2) designing a region‐based machine learning model with a preprocessor, a candidate detector, a feature extractor, and a classifier, and 3) an adversarial training and evaluation method to overcome the inconsistent data labels. Applying real panel images from the display manufacturing line as my test set, my trained model achieved a recall rate of 100% and a precision rate of over 90%.
17‐2: Invited Paper: Simulation Based Artificial Intelligence for Displays
Authors: Kim Yongjo , Baek Seungin , Kim Hoilim , Kang Min , Seo Yudeok , Cho Hyunguk , James Richard , Kwag Jinoh
Published: June 2021

In this paper, simulation‐based artificial intelligence is applied to discover new materials, and to aid in backplane and module design in order to realize high performance organic light emitting diode displays. Additionally, image quality restoration based on deep learning is introduced for a new display form factor in which the camera is positioned beneath the display panel.
20‐3: Ultra‐High‐Performance Blue Fluorescent OLED with Efficiency Over 250 cd/A/CIEy Using Organic Carrier‐Transport Material with Low Refractive Index
Authors: Watabe Takeyoshi , Kawano Yuta , Kubota Tomohiro , Tomida Airi , Kitano Yasushi , Tosu Takao , Fukuda Keito , Narukawa Ryo , Nowatari Hiromi , Ohsawa Nobuharu , Seo Satoshi , Yamazaki Shunpei
Published: June 2021

By developing low‐refractive‐index organic hole‐ and electron‐transport materials enabling the efficiency (cd/A/CIEy) of a top‐emission blue fluorescent OLED to be increased by 12% and 11%, respectively, the blue fluorescent OLED has achieved the ultra‐high efficiency over 250 ca/A/CIEy without the need of a special light‐outcoupling structure or film.
22‐1: Invited Paper: Latest Evolution of Small Molecule Based Emissive Layers for Ink Jet Printed OLED Displays
Authors: Stolz Sebastian , Meyer Sebastian , Hayer Anna , Linge Rouven , Engel Miriam , Rodríguez Lara-Isabel , Hamburger Manuel , Tseng Hsin-Rong , Jatsch Anja , Anémian Rémi
Published: June 2021

This article reviews the current performance of inkjet printed OLEDs. Recent progress on the crucial parameter of blue sub‐pixel lifetime is shown, achieved by improving the stability of the emissive material. By adjusting the charge balance towards highest efficiency, an external quantum efficiency of 11% can be achieved. Further progress on efficiency is also illustrated for red devices. Within latest R&D type material, a significant efficiency increase can be observed by an improvement of the horizontal orientation of the emissive material. Prospectively, this will close the gap between evaporated and printed red devices.
25‐2: Invited Paper: Predicting Excited State Lifetimes from Scratch Using Quantum Theory: Results from the ORCA Software
Authors: de Souza Bernardo , Riplinger Christoph , Berraud-Pache Romain
Published: June 2021

Here we will comment on how one can make use of the newest developments in quantum theory, implemented in the ORCA software, to predict excited state lifetimes from scratch. Starting only from the Lewis structure of a given molecule, now it is possible to compute or estimate its photophysical rates and even emission color of OLEDs.
25‐3: Machine‐Learning‐Assisted Materials Discovery of Blue Emitter for More Efficient and Durable OLED Device
Authors: Kim Sohae , Cho Dahye , Kim Seran , Kang Sunwoo , Koh Eunkyung , Kang Iljoon , Kim Hoilim , Mi Cho Young , Kim Yongjo
Published: June 2021

While a more efficient and stable emitter with a deep blue color is essential for a better performance of organic light‐emitting diodes (OLED) devices, obtaining such materials is extremely challenging. In the current work, we have developed a tool to assist the discovery of blue OLED materials by applying a v‐HTS of materials based on the properties predicted using ML and a ML‐predictabiltiy scale. In this study, the materials of interest include both Pt (II) phosphor complexes [1−3] and thermally activated delayed fluorescence materials for blue dopants [4−6]. We have also developed a user‐friendly version that includes most of the algorithms used in this study, which is available on an internal web‐based simulation platform.
26‐3: Invited Paper: High Performance and Long Device Lifetime Organic Light‐emitting Diodes Using a Tetradentate Platinum (II) Emitter
Authors: Li Huiyang , Lam Tsz-Lung , Tan Xiaofeng , Dai Lei , Che Chi-Ming
Published: June 2021

The realization of high performance green organic light emitting diodes with long device lifetime using a platinum emitter is demonstrated in this work. The platinum emitter shows a short emission lifetime of 2.7 μs in thin film and a high Td of 489 °C. The Pt OLED with 9 wt% doping concentration exhibited an EQE of up to 20.4% and a current efficiency of up to 70.6 cd A−1 at a current density (luminance) of 20 mA cm−2 (14110 cd m−2), respectively. Notably, a respectable device lifetime (LT95) of 373 h at 10000 cd m−2 has been achieved, and this value is comparable to the reference Ir complex.
26‐4: High Performance Multiple‐Sensitizing Process Red Hyperfluorescence Device with Assistant Emission Layer (AEL)
Authors: Liu Xinghua , Zhang Xiaojin , Wu Yong , Sun Haiyan , Wang Siqi , Wang Dan
Published: June 2021

In this work, through analysis of excition distribution mechanism, the multiple‐sensitizing process red hyperfluorescence top–emission device achieved unprecedent high current efficiency of 53.6 cd/A with CIE (0.666, 0.334), LT95 of 900 hrs and low voltage of 4.15 V at current density of 15mA/cm2 among the reported Hyperfluorescence OLEDs.
27‐2: Invited Paper: Host Strategy for High‐Efficiency and Long‐Lifetime Blue Organic Light‐Emitting Diodes
Authors: Yeob Lee Jun
Published: June 2021

Recently, high efficiency and long lifetime blue organic light‐emitting diodes are being actively studied for commercialization. The blue technologies include phosphorescent devices, thermally activated delayed fluorescence devices and hyperfluorescence devices. They all require high triplet energy host to fully utilize the triplet excitons of the emitting materials. Therefore, it is very important to develop the high triplet energy hosts for the blue organic light‐emitting diodes. In this paper, we present a strategy to develop the high triplet energy hosts for high efficiency and long device lifetime.
29‐3: An Easy‐to‐Implement and Low‐Cost VR Gaze‐Tracking System
Authors: Sun Jiankang , Zhang Hao , Chen Lili , Zhang Menglei , Xue Yachong , Li Xinkai
Published: June 2021

The main contribution of this paper is to provide an easy‐to‐implement and low‐cost gaze tracking system for near‐eye display, which can meet the needs of application scenarios such as near‐eye display interaction and foveated rendering. The hardware of the system is an infrared camera combining with an annular infrared light source of 850nm to achieve image acquisition. The software algorithm is based on the pupil segmentation algorithm of sliding window with adaptive threshold, which can achieve the precise pupil segmentation, the pupil ellipse fitting method that can achieve the precise pupil positioning, and the polynomial model that can establish the mapping between the pupil center and the fixation point. Consider the real application environment, the eye position compensation method based on the canthus point is adopted to achieve a more stable gaze calculation which completed a more perfect VR gaze‐tracking system. For the experimental results, the average error for the system is 0.55° in the horizontal direction and 0.63° in the vertical direction, the latency on the Intel I7‐6700HQ CPU is about 3.5 ms, which indicates that the system can achieve the gaze‐tracking calculation with high speed and precision that can be used in VR.
30‐1: Invited Paper: High Aspect Ratio OLED Microdisplay with Pin Mirror Lens for Small Form Factor AR Devices
Authors: Kang Chan-Mo , Shin Jin-Wook , Choi Sukyung , Kwon Byoung-Hwa , Cho Hyunsu , Cho Nam Sung , Lee Jeong-Ik , Kwon Seungjoon , Lee Hyunkoo , Park Soon-Gi , Kim Youngjoon , Ha Jeonghun , Kim Jaehyeok , Lee Jeong Hwan , Kim Hokwon , Cho Ara , Park Sang Hyun , Kim Minseok , Kim Sang Tae , Lee Jong Soo , Lee Seung No , Bin Im Yu , Koo Jung-Sik , Park Jiyong , Byun Chun-Won
Published: June 2021

In this paper, we developed the high aspect ratio color OLED microdisplay and combined with the pin mirror lens, providing a wide FoV AR device in a small form factor. The white OLED exhibited the luminance of 14,072 cd/m2 and current efficiency of 33.8 cd/A at 9 V. To reduce optical crosstalk, color filters were directly patterned on the chip. The high aspect ratio OLED microdisplay was then combined with the pin mirror lens, resulting in maximum horizontal FoV 46.6° at the lens thickness of 4 mm. By using such a simple display module, we successfully demonstrated the small form factor AR device.
30‐3: Student Paper: Polarization State Exploration and Management in Waveguide Display with Polarization Volume Gratings
Authors: Feng Xiayu , Lu Lu , Lee Yun-Han , Yaroshchuk Oleg , Silverstein Barry , Bos Philip
Published: June 2021

In this work, we focus on the polarization state input, propagation and output of waveguide display device using polarization volume holographic gratings (PVH) as couplers. First, a detailed study of the transmissive PVH (T‐PVH) is presented in terms of diffraction efficiency, polarization selectivity and polarization output, which is expected to be used as the waveguide input/output couplers. The configuration here called “Slanted T‐PVH” has the advantageous property of maintaining orthogonal circular output polarization states. Then, the polarization state management of light propagating in waveguide is considered. The issue that the polarization state of the light can change as it propagates in the waveguide due to total internal reflection (TIR) is made clear, that has a negative effect on the waveguide PVH input/output couplers efficiency, image uniformity, and the polarization multiplexing capability. Finally, it is shown that applying compensators to correct the polarization state change can solve the polarization state change in a waveguide.
33‐1: Invited Paper: Liquid Crystals for Virtual Reality (VR)
Authors: Peng Fenglin , Geng Ying , Wang Junren , Lu Lu , Zhao Yang , Maimone Andrew , Gao Weichuan , Huang Yuge , Gollier Jacques , Silverstein Barry
Published: June 2021

Liquid crystal has been widely used in display applications, including Augmented Reality (AR) and Virtual Reality (VR) headset. In this paper, we discuss how liquid crystal technology can enable a virtual reality (VR) headset with glass‐type form factor, better image quality, and wearing comfort.
33‐4: Fast Switchable Multi‐Focus Polarization‐Dependent Ferroelectric Liquid‐Crystal Lenses for Virtual Reality
Authors: Yuan Zheng-Nan , Cheng Ming , Yu Xin-Yi , Sun Zhi-Bo , Li An-Ran , Mukherjee Souptik , Kwok Hoi-Sing , Srivastava Abhishek. K.
Published: June 2021

In this paper, we propose a fast switchable lens system with multiple focal points. Specifically, the combination of the Electrically Suppressed Helix Ferroelectric Liquid Crystal (ESHFLC) based polarization rotator and a passive polarization‐dependent LC lens can switch the focal points at high speed (50µs). Moreover, a cascaded assembly of 3 such lens units shows 8‐focal points, with a fast response time of 50µs. This device shows promising potential for VR and depth‐mapping.
36‐1: Optical Fingerprint Recognition Technology Based on Liquid‐Crystal Displays
Authors: Zhang Guiyang , Yang Huanli , Shuai Chuan , Zha Guowei , Shi Tengteng , Bu Huanhuan , Liu Guanghui
Published: June 2021

This paper introduces the current optical schemes of LCD optical fingerprint recognition, analyzes the structure and signal characteristics in detail. The simulation and measurement results show that fingerprint recognition effect is not only dependent on the valley/ridge contrast ratio, but also dependent on the valley/ridge signal difference. Finally, the development direction of LCD optical fingerprint recognition in the future is illustrated by combining the advantages of different optical structures.
36‐3: Microlens Collimation Film with Near‐Infrared Spectral Filter for Large‐Area Fingerprint Sensor
Authors: Yang Joseph , Schleusner Serena , Fabick Ryan , Denker Martin , Pham Tri , Chen Qunyi
Published: June 2021

A microlens collimation has been manufactured using a roll‐to‐roll process to enable large‐area image sensing applications. This film was made with 3M proprietary precision micro‐replication process. Measurement techniques and a companion NIR filter for ambient light rejection are also discussed in this paper.
38‐4: Improving Performance of Curved TFT‐LCD with extreme curvature
Authors: Yu Liang , Zhao Yongchao , Wang Yanan , Song Yanjun , Hsieh Chung-Ching , Xiao Juncheng , Zhao Bin
Published: June 2021

Flat TFT‐LCD with curved back light units(BLU) can obtain curved display effect. However, when the Flat TFT‐LCD bent with external force, there will be blocky black mura on both left and right sides, which makes the display effect worse. After analyzing a large number of blocky black mura phenomena and corresponding pre‐tilt angle data of curved TFT‐LCD, we summarized the quantitative relationship between the blocky black mura and pre‐tilt angle, and established a theoretical equation, which can be used to prejudge whether there will be blocky black mura after the TFT‐LCD bent, and to guide the improvement of blocky black mura.
38‐7: A High Reliability PEDOT:PSS/Graphene Transparent Electrode for Liquid Crystal Displays
Authors: Shao Yuan , Zhang Xia , Liu Gang , Tang Shi , Ching Hsieh Chung , Xiao Juncheng , Zhao Bin
Published: June 2021

A 32″ liquid crystal displays (LCD) was assembled by a high reliability Ink‐jet printing PEDOT:PSS/Graphene thin film as its transparent electrode, and the electro‐optical properties of this LCD cell were comparable to the ITO competitor.
41‐1: Invited Paper: Dynamic Holography for Automotive Augmented‐Reality Head‐Up Displays (AR‐HUD)
Authors: Christmas Jamieson , Smeeton Tim M.
Published: June 2021

In recent months we have begun to witness the introduction of Augmented Reality Head Up Displays in the latest vehicles, thus far these devices have employed conventional display technologies such as LCDs or DMDs. However, the large display areas & high pixel counts associated with AR‐HUDs present a number of challenges for the incumbent technologies. Dynamic holography is an alternative display technology which has been maturing rapidly over the past decade. The application of this technology to AR‐HUD has a number of distinct advantages most notably that its image formation process enables a number of different architectures reducing the barrier to integration.
42‐1: Invited Paper: Perceptual Quality Performance for Automotive Display Requirement
Authors: Lee Don Gyou , Shin Hong Seop , Lee Buyeol , Yoon Sooyoung
Published: June 2021

A new image quality enhancement technology in terms of perceptual performance without increasing luminance specification values is introduced. Various perceptual factors such as brightness, local contrast, sharpness at high frequency image, and overall colorfulness of image are improved when optical specification values of display are fixed. Three Plastic OLED (POLED) samples were prepared to compare image quality levels between conventional and enhanced one, and a series of visual assessment has been carried out at different ambient conditions (5,000 lx, and 45,000 lx) in order to verify the performance of the developed technology. The luminance values of proposed and conventional samples were ranged from 800 to 1,000 cd/m2. The results show that the proposed technology outperforms conventional ones, even though the luminance value of conventional sample was higher than that of proposed technology.
42‐3: Advanced HMIs and Evaluation of Various Display Techniques for Autonomous Robots in Public Spaces
Authors: Blankenbach Karlheinz , Charrier Etienne , Babel Franziska , Hochdorfer Siegfried
Published: June 2021

Latest service robots navigate autonomously in public spaces, which is new to pedestrians. Trajectory information is strongly recommended. Our user study propose dynamic visualizations to avoid confusion and fear. We prototyped and evaluated various approaches for bright indoor conditions such as animated projection and LED lighting as well as displays.
43‐1: Automotive Autostereoscopic 3D Display
Authors: Kreuzer Markus , Pross Achim , Ewen Christoph , Song Kiuk , Purzycki Adam
Published: June 2021

The new S‐Class introduced a newly developed 3D instrument cluster display as one of its highlights. The display enables real depth perception without the need for glasses and without compromising visual quality. This paper describes the requirements, system design and technical realization of a fully position‐adaptive autostereoscopic display.
45‐1: A Novel 88‐inch 8K OLED Display for Premium Large‐Size TVs
Authors: Shin Hong-Jae , Choi Soo-Hong , Kim Dong-Myoung , Han Seong-Eok , Bae Sung-Joon , Park Sin-Kyun , Kim Han-Seop , Oh Chang-Ho
Published: June 2021

In this paper, we present the novel 88‐inch 8K OLED display for premium large size TVs. New key technologies are applied to 8K OLED display, including a coplanar type IGZO TFT backplane, simple pixel structure with white OLED, current compensation method, large area high speed GIP, pixel charging rate improvement, and driving system with two chip timing controllers. Those technologies enable high image quality characteristic and high reliability of OLED panel. Using the developed 8K OLED displays, we have successfully launched 88‐, and 77‐inch 8K OLED TVs.
46‐3: Invited Paper: Design and Process of 2D Backlight Beyond HDR 5000 Nits
Authors: Akimoto Hajime , Yamamoto Atsushi , Washio Hajime , Nakano Taketoshi
Published: June 2021

HDR 2D‐backlight designs and some process for each of automotive/monitor, mobile device, and future Reality applications are presented. On‐chip lens and confining wall reflector structure are suitable for automotive/monitor applications, and 5,000nits of peak brightness will be performed in real usage. The white LED chip architecture is proposed for mobile applications of 2‐1mm thin backlight. The power efficiency is evaluated to be almost double, and the 500lux ambient light contrast is 5 times larger than a 15.6‐inch OLED display. The 0.5mm thin film backlight with micro‐LED chips for Reality applications is proposed.
47‐2: Invited Paper: UBplus — A LC Display Technology Perfect for Energy Saving
Authors: Goetz Achim , Laut Sven , Laur Juergen , Hirschmann Harald
Published: June 2021

“Energy efficiency” and “Green Technology” are currently buzzwords in the display industry. Upcoming mandatory energy regulations are further driving this development, challenging the display industry. Within this context, we would like to demonstrate the advantage of UBplus LC technology for application in TVs. UBplus technology using LC mixtures with negative dielectric anisotropy offers a unique solution to this challenge due to a high transmittance level, whilst retaining the classic FFS cell layout. This paper summarizes the recent developments of liquid crystal mixtures for UBplus.
47‐3: Invited Paper: Development of Reflective LCDs with High Contrast Ratio and High Reflectivity
Authors: ZHANG Ruichen , XUE HAILIN , SHAO Xibin , LI Hu , LIAO Liqing , CHEN Yanqing , WANG Hui , LIU Yanni , ZHENG Qi , ZHAN Hongming , CHEN Xi , WANG Kaixuan
Published: June 2021

A kind of reflective mode LCD was reported years ago by professor Shin‐Tson Wu, called Mixed‐mode Twisted Nematic (MTX) LCD[1]. Based on MTN mode RLCD, we promoted the contrast ratio and reflectivity of RLCD by optimizing the cell structure and pixel design. Meanwhile, according to controlling the different optical layer axis directions and using new type materials, the contrast ratio and reflectivity are increased further. To improve the visibility of RLCD in a dark environment, we also developed the front light unit solution.
47‐4: Student Paper: Ambient Light and Human Vision Effects on High‐Dynamic‐Range Displays
Authors: Hsiang En-Lin , Yang Qian , He Ziqian , Zou Junyu , Wu Shin-Tson
Published: June 2021

Ambient light and human vision effects on high‐dynamic‐range mini‐LED backlit LCDs (mLCDs) and OLED displays are investigated. Subjective visual experiment is also conducted to validate our analyses. As the ambient light brightness increases, the required local dimming zones for mLCDs to achieve comparable visual quality with OLED displays decreases dramatically.
47‐5: Distinguished Paper: Development of Reversed‐Dispersion Liquid‐Crystal Film to Improve the Display Quality of HDR‐IPS Panels
Authors: Iwasaki Tatsuya , Nakamura Yuki , Sumi Toshikazu , Ohmuro Katsufumi , Suzuki Masaaki , Ito Yoji
Published: June 2021

We have developed a new reverse dispersion retardation film with a thickness of 4 for IPS panels, which achieves excellent viewing angle performance, notably for oblique contrast ratio and color. HDR‐IPS panels applied this reverse retardation film could achieve a significant improvement of the halo viewing from oblique angle.
48‐4: Invited Paper: High‐resolution Integral Imaging 3D Display System
Authors: Zhang Han-Le , Ren Hui , Xing Yan , Xia Yun-Peng , Li Shuang , Deng Huan , Wang Qiong-Hua
Published: June 2021

A high‐resolution integral imaging 3D display system without color moiré pattern and graininess is proposed. The system consists of a 2D display, a micro‐lens array, a holographic diffuser, and a transmissive mirror device. The experimental results prove the feasibility of the proposed system.
48‐5: Eye‐sensing Light Field Display for Spatial Reality Reproduction
Authors: Aoyama Koji , Yokoyama Kazuki , Yano Tomoya , Nakahata Yuji
Published: June 2021

We have developed the eye‐sensing light field display (ELFD), which lets the user experience a virtual space as if it were real. This is made possible by real‐time light field rendering with its optical design based on eye‐sensing and by taking into account human perceptual characteristics.
50‐4: Optical Design of Corner‐Cube Retroreflectors with Inclined Curved Optical Surfaces for Directional Scattering Projector Screen
Authors: Käläntär K. , Uchida T.
Published: June 2021

An array of hollow corner cube retroreflectors (CCR) with inclined and curved optical surfaces has been designed to realize a directional scattering projector screen. The characteristics of our previously reported projector screen were further modified by emphasizing on the design accuracy and precision of the screen unit cell. The rhombus screen unit cell which is a combination of two directional scattering CCRs with equilateral triangle apertures set back to back, was modified to increase the scattering light. The source of optical noise on the screen and the result of modification are reported.
52‐2: Research on Evaluation Method of Display Visual Effect
Authors: Zhao Hongwei , Chen Jianyou , Mu Qi , Liang Zhixing , Zhong Caijiao , Zhou Ting , Li Junyi
Published: June 2021

In order to quantify motion blur of display, MPRT has been written into the VESA measurement standard. Besides, visual effect should be evaluated in different application scenarios. In this paper, a high‐speed camera is used for motion tracking and static capture of moving picture. By characterizing the transition process from frame to frame and combining human vision, a new evaluation method is provided. According to objective quantification and subjective judgment, we can define the visual effects of daily application more intuitively.
52‐3: Student Paper: A Quantitative Method for L0‐Leakage Sensitivity in TFT‐LCDs Based on JND Energy Ratio
Authors: Han-yan SUN , Ming-hui ZHANG , Wei-tao CHEN , Xiao-Peng CUI , Xiao-jian YANG
Published: June 2021

In this paper, a quantitative evaluation method of L0 light leakage sensitivity based on JND energy ratio is established by studying the optical characterization and physical significance of L0 light leakage phenomenon. This method uses continuous quantitative indicators instead of human eye evaluation, which fully improves the accuracy and repeatability, and it can also predict the L0 light leakage level after the test module is assembled into the system set. An optical test system was built to simulate the influence of the system set. The liquid crystal module samples with different glass thickness and different sealant were tested. The test results were consistent with the qualitative judgment results of the human eye after the test module is assembled into tablet PC, and the similar level that the human eye can't be distinguished can be quantitatively distinguished. The repeatability error of the method was only 0.89%.
52‐4: Simulation of Dynamic MTF Measurement Method for Pixelated Displays
Authors: Masaoka Kenichiro
Published: June 2021

A method for measuring the dynamic modulation transfer function (MTF) of a display is introduced. A single moving vertical line is displayed, and a high‐speed imaging light measuring device (LMD) captures a small region of the screen. The effect of smooth‐pursuit eye‐tracking of the moving line is simulated by aggregating a series of supersampled luminance profiles.
53‐2: Directional variations of specular reflections from displays
Authors: Becker Michael E.
Published: June 2021

We apply analysis of the point‐spread function for evaluation of details of directional variations of display reflectance in the vicinity of the specular direction. This approach is used for obtaining more data on the effect of light sources with different apertures in the specular direction as a basis for ergonomic rating and for separation of disturbing display reflections from intended information‐carrying reflection components.
55‐2: Invited Paper: Nanomesh Based on Skin Electronics
Authors: Yokota Tomoyuki , Lee Sunghoon , Someya Takao
Published: June 2021

We have developed a nanomesh based on skin sensors that can detect physiological signals such as electrocardiogram (ECG), pressure, and acoustic detection. Nanomesh sensors have high gas permeability and softness. Owing to the high gas permeability, the nanomesh sensor did not cause inflammation when the sensor was attached to the skin for a week. Furthermore, we developed a wireless ECG monitoring system by combining a nanomesh sensor and a textile‐based wireless module.
56‐5: Image Sensor Using IGZO‐TFT Backplane with Sacrificial Barrier Layer for X‐Ray Detector
Authors: Zhan Xiangmi , Cheng Jin , Hou Xuecheng , Li Cheng , Che Chuncheng
Published: June 2021

Amorphous IGZO TFT arrays have been developed as backplanes for 17ç17 inch flat panel X‐ray detector. A sacrificial barrier layer (SBL) is introduced to protect the a‐IGZO channel from H plasma atmosphere, which can effectively solve the problem of negative threshold voltage (Vth) shift and/or even TFT continuously turn‐on.
58‐1: Invited Paper: Overcoming the Challenges in microLED Inspection and Manufacturing
Authors: Lewis David , Dechter Rimma , Ley Ryan , Wong Matthew , Khoury Michel
Published: June 2021

MicroLED displays offer many advantages over existing display technologies, but manufacturing challenges remain before they can be commercially viable. InZiv is developing new microLED inspection tools with the highest resolution in optical, spectral, and structural characterization. This paper reviews critical challenges facing the industry and solutions to address them.
58‐3: Invited Paper: Color Uniformity of μLED Displays: New Color Calibration Concept for Fast and Accurate Optical Testing
Authors: Steinel Tobias , Wolf Martin
Published: June 2021

Superior properties of μLEDs for display applications challenge metrology with, eg, narrow emission bandwidth and enormous wavelength variability depending on their electronic driving parameters. Therefore, we developed new imaging test solutions to make color uniformity measurements fast and highly accurate even for strongly varying spectral properties of μLEDs.
59‐6: Directed Electrostatic Microassembly for MicroLED Display
Authors: Rupp Bradley B. , Crawford Lara S. , Lu Jeng Ping , Plochowietz Anne , Biegelsen Dave , Raychaudhuri Sourobh , Butylkov Sergey , Wang Yunda , Chow Eugene M.
Published: June 2021

We are developing a new chip integration tool based on massively parallel deterministic sorting and assembly, aiming to achieve the low cost of printing with the control of pick and place. Such a tool would enable scalable microLED display manufacturing and heterogeneous integration for advanced functionality. We describe a prototype system demonstrating continuous line by line assembly, and report single chip speed measurements of a centimeter per second, suggesting the approach could eventually support high throughput.
60‐3: Invited Paper: Borderless Tiling MicroLED PixeLED Matrix Display
Authors: Liu Ying-Tsang (Falcon) , Li Yun-Li
Published: June 2021

MicroLED display is an emerging technology with high brightness, high contrast ratio, and wide color gamut. Based on our proprietary PixeLED Matrix™ utilized by PixeLED® display and SMAR‐Tech™ repair technology, we could build borderless and tiling MicroLED displays with mature Surface‐Mount Technology process.