{"title":"Recent progress of organic light-emitting diode microdisplays for augmented reality/virtual reality applications","authors":"Chan-mo Kang, Hyunkoo Lee","doi":"10.1080/15980316.2021.1917461","DOIUrl":"https://doi.org/10.1080/15980316.2021.1917461","url":null,"abstract":"Microdisplays have been used in various applications such as beam projectors, view finders of digital cameras, projection TVs, night vision for military use, and augmented reality/virtual reality (AR/VR) devices. Organic light-emitting diode (OLED) microdisplays have attracted much attention as main displays of glass-type and head-mounted-type AR/VR devices due to their rich colors, high contrast ratio, fast response time, small form factor, and high resolution. This review investigates the device, process, pixel circuit, and panel technologies for OLED microdisplays. In addition, the technology status and issues of OLED microdisplays are discussed.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"23 1","pages":"19 - 32"},"PeriodicalIF":3.7,"publicationDate":"2021-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1917461","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47154384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Indium oxide nanomesh-based electrolyte-gated synaptic transistors","authors":"Wei Qin, B. Kang, Jongyeop An, Hyun Jae Kim","doi":"10.1080/15980316.2021.1911866","DOIUrl":"https://doi.org/10.1080/15980316.2021.1911866","url":null,"abstract":"ABSTRACT Based on the movement and accumulation of ions in the 1-ethyl-3-methylimidazolium dicyanamide ([EMIM]DCA) electrolyte under a positive gate bias, the electrical double layer (EDL) was formed between a nanomesh channel and the [EMIM]DCA electrolyte to contribute to the increase in the conductance of the channel. The basic functions of artificial synapses, such as excitatory postsynaptic current (EPSC), paired pulse facilitation (PPF), short-term plasticity (STP), and long-term plasticity (LTP), are realized successfully. Besides, the high-pass filter function was implemented, which shows the application potential of the device in signal processing.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"179 - 185"},"PeriodicalIF":3.7,"publicationDate":"2021-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1911866","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48499230","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Interfaces and pattern resolution of inkjet-printed organic light-emitting diodes with a novel hole transport layer","authors":"D. Yoon, Y. Kang, R. Bail, B. Chin","doi":"10.1080/15980316.2020.1866090","DOIUrl":"https://doi.org/10.1080/15980316.2020.1866090","url":null,"abstract":"In this paper, the effects of the combination of solvents on the uniformity of a dried emitting layer and on device performance were studied. Green emitter inks with various solvents were prepared, and it was seen that good film uniformity of printed layers could be obtained with a solvent mixture with different boiling points, which reduced the coffee ring effect on a dried surface. During the inkjet process, the drop injection condition aiming was also controlled for better drop-to-drop spacing and reduction of the line-edge roughness. Printed patterns of a small molecular/polymer hybrid emitting layer, composed of the chlorobenzene-dichlorobenzene solvent mixture, showed significantly reduced roughness of the microscopic surface and improved efficiency of the inkjet device, at levels nearly comparable to those of spin-coated patterns. A suitable hole transport layer (HTL) was also further developed as an interfacial material, prior to the solution processing of the emitter. The cross-linkable HTL was composed of triphenylamine as the cross-linking unit and a fluorene-based compound. At the optimized condition of the solvent formulation, printed droplets within 100 µm× 300 µm pixels formed a uniform stripe without remarkable coffee-ring defects and line-edge surface roughness.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"91 - 98"},"PeriodicalIF":3.7,"publicationDate":"2021-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2020.1866090","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47148982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Security use of bilayer dichroic films made of liquid crystal polymer networks","authors":"Geonhyeong Park, D. Yoon","doi":"10.1080/15980316.2021.1905723","DOIUrl":"https://doi.org/10.1080/15980316.2021.1905723","url":null,"abstract":"ABSTRACT We report on bilayer dichroic dye-doped liquid crystal (BDLC) films for patternable color codes, which can be used in anti-counterfeiting applications such as security codes and, unlike the conventional single-layer LC color films, show unique color changes depending on the direction of the polarization of the incident light that passes through them. This is a facile way to enhance the security level of security codes. BDLC films are fabricated by laminating two single-layer LC polymer network films with crossed optical axes. We believe that BDLC films can be used as a new platform for a security-enhanced anti-counterfeiting code that can replace complex chiral materials or expensive plasmonic particles.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"173 - 178"},"PeriodicalIF":3.7,"publicationDate":"2021-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1905723","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45538371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chan-mo Kang, Jin‐Wook Shin, Sukyung Choi, Byoung‐Hwa Kwon, Hyunsu Cho, N. Cho, Jeong-Ik Lee, Hyunkoo Lee, Jeong Hwan Lee, Hokwon Kim, Ara Cho, Sang Hyun Park, Minseok Kim, Soon-gi Park, Young-Joon Kim, Jeonghun Ha, Jaehyeok Kim, S. Kim, J. S. Lee, Seung No Lee, Yu-Bin Im, C. Byun
{"title":"High aspect ratio microdisplay and thin optical component for glass-like AR devices","authors":"Chan-mo Kang, Jin‐Wook Shin, Sukyung Choi, Byoung‐Hwa Kwon, Hyunsu Cho, N. Cho, Jeong-Ik Lee, Hyunkoo Lee, Jeong Hwan Lee, Hokwon Kim, Ara Cho, Sang Hyun Park, Minseok Kim, Soon-gi Park, Young-Joon Kim, Jeonghun Ha, Jaehyeok Kim, S. Kim, J. S. Lee, Seung No Lee, Yu-Bin Im, C. Byun","doi":"10.1080/15980316.2021.1902405","DOIUrl":"https://doi.org/10.1080/15980316.2021.1902405","url":null,"abstract":"Organic light-emitting diode (OLED) microdisplays have attracted much attention as displays for small form factor augmented reality (AR) devices. To realize glass-like thin and wide field of view (FoV) AR devices, we designed a display module with a high aspect ratio microdisplay and a thin optical component. For the high aspect ratio microdisplay, we developed the color OLED microdisplay with a 32:9 aspect ratio and a 0.8-inch diagonal ∼2,490-ppi CMOS backplane. To express color and reduce optical crosstalk, we fabricated the color filter (C/F) patterning directly on the white OLED. We also developed a pin mirror lens with 11 pin mirrors to improve the optical efficiency and quality with a thin lens. By combining the microdisplay with LetinAR’s pin mirror lens, we successfully demonstrated an AR device with a wide horizontal FoV of 46° but with a small form factor 4 mm lens.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"163 - 171"},"PeriodicalIF":3.7,"publicationDate":"2021-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1902405","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45591610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effects of the grain boundary protrusion position on the off-state current of polycrystalline silicon thin-film transistors","authors":"JooWon Yang, Yong-Sang Kim, J. Jeon, K. Park","doi":"10.1080/15980316.2021.1896587","DOIUrl":"https://doi.org/10.1080/15980316.2021.1896587","url":null,"abstract":"ABSTRACT We report the effects of grain boundary (GB) protrusion on the off-state current (IOFF) of p-channel polycrystalline silicon thin-film transistors by using three-dimensional technology computer-aided design (TCAD) simulation. We found that the IOFF at a high drain bias, VDS = −10 V, varies more than 10 times as the position of the GB protrusion changes, whereas it varies less than two times if the GB has no protrusion, i.e. has a flat surface. The TCAD analysis showed that the IOFF was mainly caused by band-to-band tunneling and that it increased noticeably when the GB protrusion was located at a certain distance from the highly doped drain region because the GB protrusion intensified the electric field at the drain junction. We also found that the IOFF increases further when the GB line is not perpendicular to the channel direction but has some tilt angle because the GB protrusion necessarily encompassed a critical region that maximized the electric field when it was positioned within the GB protrusion.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"153 - 162"},"PeriodicalIF":3.7,"publicationDate":"2021-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1896587","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42198546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Technical status of top-emission organic light-emitting diodes","authors":"Seong Keun Kim, Raju Lampande, J. Kwon","doi":"10.1080/15980316.2021.1876173","DOIUrl":"https://doi.org/10.1080/15980316.2021.1876173","url":null,"abstract":"Top-emission organic light-emitting diodes (TEOLEDs) that contain semi-transparent metal top cathodes and highly reflective anodes have been actively researched for display applications due to their many advantages such as their high aperture ratio, good color purity, and high efficiency. In this research, the technical design of TEOLEDs used in organic light-emitting diode (OLED) displays is reviewed, covering the optical theory with the microcavity effect, optical losses, and the importance of the Purcell effect in the optical calculation. The key methodologies for addressing the high efficiency and low driving voltage of TEOLEDs are also discussed.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"115 - 126"},"PeriodicalIF":3.7,"publicationDate":"2021-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1876173","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43548133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A more reliable defect detection and performance improvement method for panel inspection based on artificial intelligence","authors":"Eui-Young Jeong, Jaewon Kim, Wonhyouk Jang, Hyun-Chang Lim, Hanaul Noh, Jongmyong Choi","doi":"10.1080/15980316.2021.1876174","DOIUrl":"https://doi.org/10.1080/15980316.2021.1876174","url":null,"abstract":"This paper presents a practical approach to automatic inspection of display panels based on deep neural networks. The approach accurately detects appearance defects on display panels in various sizes and shapes within a short computation time. We propose a novel reliable detection network using the multi-channel parameter reduction method, which preserves high-resolution features of defects at sub-sampling steps of convolutional operations. Our proposed network consists of two sub-networks with different functions: pixel-wise segmentation of defect regions and distinction of real defects from fake defects. Compared with conventional deep learning networks, the proposed network achieved a more accurate detection rate, i.e. an F1-score of 81%, for real defect images acquired from an actual display manufacturing process. In addition, we propose a conditionally paired generative network that generates synthetic images of scarce defects under four different lighting conditions. The proposed networks improved the detection accuracy and can be applied to automatic inspection processes in display manufacturing factories in place of human inspection.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"127 - 136"},"PeriodicalIF":3.7,"publicationDate":"2021-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2021.1876174","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42731530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Passivation layer effect on the positive bias temperature instability of molybdenum disulfide thin film transistors","authors":"Woonggi Hong, D. Oh, Sung‐Yool Choi","doi":"10.1080/15980316.2020.1776407","DOIUrl":"https://doi.org/10.1080/15980316.2020.1776407","url":null,"abstract":"As two-dimensional (2D) materials have a large surface to volume ratio, the stability of thin film transistors (TFTs) is likely to be lowered with air exposure. Therefore, we study the positive bias temperature instability (PBTI) of chemical vapor deposition (CVD) grown molybdenum disulfide (MoS2) TFTs before and after deposition of a passivation layer. The results of the PBTI study demonstrate that the fabricated devices adjust to the stretched-exponential model, which shows a threshold voltage shift attributed to the charge trapping mechanism. However, by depositing the passivation layer (Al2O3) that physically blocks the charge transfer process with O2 and H2O adsorbed to the surface of the MoS2 channel, the threshold voltage shifted reduces from 10 V to 7.4 V under stress condition. The quantitative value of tau (τ), one of the fitting parameters of the stretched-exponential model, also decreases from 6453 s to 5153 s, resulting in improved device stability.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"13 - 19"},"PeriodicalIF":3.7,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2020.1776407","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45551485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Optical analysis of the dual-microcavity effect in a red light-emitting organic device","authors":"A. Mikami","doi":"10.1080/15980316.2020.1848934","DOIUrl":"https://doi.org/10.1080/15980316.2020.1848934","url":null,"abstract":"ABSTRACT In this study, the effect of a dual microcavity on the luminescent characteristics and light extraction efficiency of organic red light-emitting devices with a multi-cathode structure was investigated. It was clarified that surface plasmon loss on a metal cathode was reduced to about one-fifth and can be efficiently extracted from the outside with the help of the dual-microcavity effect. About half of the radiant energy in dipole emission was successfully utilized as external and substrate modes. The luminous efficiency increased by about 1.52 times, and a narrow-band emission spectrum was observed with a forward directional red emission. The relationship between the luminescence characteristics and the dual-microcavity effect will be discussed from the viewpoint of the optical design of multi-stacked thin film devices.","PeriodicalId":16257,"journal":{"name":"Journal of Information Display","volume":"22 1","pages":"99 - 106"},"PeriodicalIF":3.7,"publicationDate":"2020-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/15980316.2020.1848934","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43010086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}