research
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Finding Human Thermal Comfort with a Watch-type Sweat Rate Sensor
(from left: Professor Young-Ho Cho and Researcher SungHyun Yoon)
KAIST developed a watch-type sweat rate sensor. This subminiature device can detect human thermal comfort accurately and steadily by measuring an individual’s sweat rate.
It is natural to sweat more in the summer and less in the winter; however, an individual’s sweat rate may vary in a given environment. Therefore, sweat can be an excellent proxy for sensing core body temperature.
Conventional sweat rate sensors using natural ventilation require bulky external devices, such as pumps and ice condensers. They are usually for physiological experiments, hence they need a manual ventilation process or high power, bulky thermos-pneumatic actuators to lift sweat rate detection chambers above skin for continuous measurement. There is also a small sweat rate sensor, but it needs a long recovery period.
To overcome these problems, Professor Young-Ho Cho and his team from the Department of Bio and Brain Engineering developed a lightweight, watch-type sweat sensor. The team integrated miniaturized thermos-pneumatic actuators for automatic natural ventilation, which allows sweat to be measured continuously.
This watch-type sensor measures sweat rate with the humidity rising rate when the chamber is closed during skin contact. Since the team integrated thermos-pneumatic actuators, the chamber no longer needs to be separated manually from skin after each measurement in order for the chamber to ventilate the collected humidity.
Moreover, this sensor is wind-resistant enough to be used for portable and wearable devices. The team identified that the sensor operates steadily with air velocity ranging up to 1.5m/s, equivalent to the average human walking speed.
Although this subminiature sensor (35mm x 25mm) only weighs 30 grams, it operates continuously for more than four hours using the conventional wrist watch batteries.
The team plans to utilize this technology for developing a new concept of cognitive air-conditioning systems recognizing Human thermal status directly; while the conventional air-conditioning systems measuring air temperature and humidity.
Professor Cho said, “Our sensor for human thermal comfort monitoring can be applied to customized or smart air conditioners. Furthermore, there will be more demands for both physical and mental healthcare, hence this technology will serve as a new platform for personalized emotional communion between humans and devices.”
This research, led by researchers Jai Kyoung Sim and SungHyun Yoon, was published in Scientific Reports on January 19, 2018.
Figure1. The fabricated watch-type sweat rate sensor for human thermal comfort monitoring
Figure 2. Views of the watch-type sweat rate sensor
Figure 3. Operation of the watch-type sweat rate sensor
2018.02.08 View 7632 -
KAIST Students Invited to the BNL
Siheon Ryee and Taek Jung Kim, combined Masters and PhD students from the Department of Physics, have been invited to be visiting researchers at the Brookhaven National Laboratory (BNL).
The BNL, located in Long Island, New York, is one of the most esteemed institutes in the United States. Ryee and Kim received the invitation from the Center for Computational Design of Functional Strongly Correlated Materials and Theoretical Spectroscopy. This center was established by scholars who have been leading this field in the United States.
The two students will be participating in developing a methodology and code for calculating strongly correlated electronic materials, and a grant of 40,000 USD will be provided to each student. This amount of support is not often awarded to researchers outside of postdoctoral programs.
Moreover, they are guaranteed to continue their combined Masters and PhD program and write their dissertations under the supervision of their advisor, Professor Myung Joon Han from the Department of Physics.
Professor Han said, “I was impressed by how well-known scholars established the center in order to cooperate with each other to solve challenging problems. Also, I was surprised and happy that my students were invited to this outstanding institute.”
“I believe that doing research with leaders in their field will give valuable experience to the students. At the same time, my students will be a great help to the scholars of the institute,” he added.
2018.01.11 View 6636 -
MoU by KAIST-Seoul-Seocho-gu for the 4th Industrial Revolution
The opening ceremony of the Yangjae R&CD Innovation Hub was held in Seoul on December 5. More than 400 guests came to the ceremony from major institutes and companies that are based in the hub. KAIST President Sung-Chul Shin, the Mayor of Seoul, Won-soon Park, and the Mayor of Seocho-gu, Eun Hee Cho, signed an MoU for Seoul to be the leading city for successfully realizing the Fourth Industrial Revolution.
The three organizations aim to cooperate with one another in various areas, including an economic boost for local job creation, technology development, and the promotion of projects through an industry-academia-institute network and fostering manpower.
Yangjae R&CD is the first facility specializing in and dedicated for Artificial Intelligence, which is the major topic of the Fourth Industrial Revolution.
The hub is comprised of enterprises specializing in AI, open co-work spaces, conference rooms, an open networking lounge, and spaces for fostering professional manpower. The hub will recruit additional enterprises and individuals who wish to move in. KAIST, an institute containing professors and researchers in the field of AI, and Modulabs, an organization becoming distinguished in AI research, will be in charge of operating the facility together.
The Yangjae R&CD Innovation Hub will operate a professional training program with participation from KAIST professors, which aims to produce 500 professionals in AI research and development by 2020. It will also provide inexpensive space as well as consultations and venture capital to startup and venture companies. It plans to find and foster 50 innovation companies by 2020.
In particular, the hub will operate a course for new AI business models 24 times over three years.
The hub also offers job consultations, academic conferences, public space for companies residing in the hub, a free GPU cluster server, technical training, seminars, forums, investment attraction, overseas expansion, and one-to-one technical consultations.
The Yangjae R&CD Zone is the place established for the Fourth Industrial Revolution by Seoul. R&CD is a concept combining Research and Development, Connection, Companies, Community, and Culture.
Seoul aims to create the Yangjae Zone as an urban innovation hub for facilitating industry-academia linkage as well as establishing a startup-settlement-growth technical ecosystem.
2017.12.11 View 8134 -
IDKAIST Graduation Show, Interative and Innovative Works
Undergraduate students from the Department of Industrial Design at KAIST opened up their graduation show in the Industrial Design Building for eight days in KAIST from November 10 and another four days in Coex, Seoul from December 7.
The students showcased their creative and novel works in the exhibition. Some designs successfully showed change concepts such as for mixing straws. There were also several projects designed to meet individual demand, such as a customized shoe-making application and personal makeup colorings.
Since the establishment of its undergraduate program in 1983, the department has held a graduation show to demonstrate four years of the students’ academic work and research performance to KAIST members, externals specialists, and the public.
Professor Daniel Saakes, who is in charge of the show, said, “Please come by the show and support the 28 students for their hard work. This year, students’ projects are more socially-oriented through applications and social media, making them easily approachable for consumers.”
2017.11.13 View 5875 -
Professor Lee's Research Selected as Top 100 National R&D Projects
A research project, led by Research Professor Ju Yong Lee from the KAIST Institute for IT Convergence, was selected as one of the Top 100 National Research and Development Projects 2017.
This research project, titled LTE-A-based Single RF Small Base Station supporting Multiple Streams, developed 300Mbps low power, low complexity and broadband small base station technology that supports 4x4 MIMO (Multiple Input and Multiple Output) by proposing a new antenna structure and a new RF (Radio Frequency) structure based on LTE-A. Professors from the School of Electrical Engineering at KAIST, Dong Ho Cho, Songcheol Hong, and Yong Hoon Lee also collaborated on the project.
The existing heterodyne method of communication systems generates the problems of increasing unit price and system complexity.
In this project, however, Professor Lee directly modulated the baseband signal from the RF stage through an impedance loading-based RF chip. This method was designed to facilitate low power as well as low complexity while supporting broadband service. Based on this, his team developed source technology for RF that can be applied to fourth and even fifth generation networks.
Furthermore, this base station is smallest among the small-cell stations so far, providing an eco-friendly installation environment. It contributes to the market for fifth generation mobile communications by reducing power consumption significantly yet providing high-capacity services.
Professor Lee said, “This technology will contribute to creating a new market and additional jobs because business based on the fifth mobile generation can provide multi-functional services, including multiband. Requiring low power and providing high-capacity services anywhere at any time will enhance national competence and reduce costs for establishing a next generation mobile communication system. It is expected that this technology will help with disseminating mobile communication infrastructure through expanding information and communication system as well as the infrastructure of island areas.”
2017.11.08 View 7504 -
Scientist of November, Professor Hyung Jin Sung
Professor Hyung Jin Sung from the Department of Mechanical Engineering at KAIST received a ‘Science and Technology Award of the Month’ given by the Ministry of ICT and Science and the National Research Foundation of Korea for November 2017. He developed technology that can exquisitely control a micrometer-scaled liquid drop on a dime-sized lab-on-a-chip. With his work, he was recognized for reinforcing research capability on microfluidics.
Lab-on-a-chip is an emerging experiment and diagnostic technology in the form of a bio-microchip that facilitates complex and various experiments with only a minimal sample size required. This technology draws a lot of attention not only from medical and pharmaceutical areas, but also the health and environmental field. The biggest problem was that technology for the temperature control of a fluid sample, which is one of the core technologies in microfluidics, has low accuracy. This limit had to be overcome in order to use the lab-on-a-chip more widely.
Professor Sung developed an acoustic and thermal method which controls the temperature of a droplet quickly and meticulously by using sound and energy. This is a thermal method that uses heat generated during the absorption of an acoustic wave into viscoelastic substances. It facilitates a rapid heating rate and spatial-temporal temperature control, allowing heating in desired areas. In addition, Professor Sung applied his technology to polymerase chain reactions, which are used to amplify DNA.
Through this experiment, he successfully shortened the reaction time from 1-2 hours to only three minutes, making this a groundbreaking achievement.
Professor Sung said, “My research is significant for enhancing the applicability of microfluidics. I expect that it will lead to technological innovations in healthcare fields including biochemistry, medical checkups, and new medicine development.”
2017.11.03 View 8144 -
Development of a Highly-Accurate Computational Model of Human Metabolism
A research team from KAIST developed a computational framework that enables the reconstruction of a comprehensive computational model of human metabolism, which allows for an accurate prediction of personal metabolic features (or phenotypes).
Understanding personal metabolic phenotypes allows us to design effective therapeutic strategies for various chronic and infectious diseases. A human computational model called the genome-scale metabolic model (GEM) contains information on thousands of metabolic genes and their corresponding reactions and metabolites, and has played an important role in predicting metabolic phenotypes. Although several versions of human GEMs have been released, they had room for further development, especially as to incorporating biological information coming from a human genetics mechanism called “alternative splicing.” Alternative splicing is a genetic mechanism that allows a gene to give rise to multiple reactions, and is strongly associated with pathology.
To tackle this problem, Jae Yong Ryu (a Ph.D. student), Dr. Hyun Uk Kim (Research Fellow), and Distinguished Professor Sang Yup Lee, all from the Department of Chemical and Biomolecular Engineering at KAIST, developed a computational framework that systematically generates metabolic reactions, and adds them to the human GEM. The resulting human GEM was demonstrated to accurately predict metabolic phenotypes under varied environmental conditions. The research results were published online in Proceedings of the National Academy of Sciences (PNAS) on October 24, 2017, under the title “Framework and resource for more than 11,000 gene-transcript-protein-reaction associations in human metabolism.”
The research team first updated the biological contents of a previous version of the human GEM. The updated biological contents include metabolic genes and their corresponding metabolites and reactions. In particular, metabolic reactions catalyzed by already-known protein isoforms were additionally incorporated into the human GEM; protein isoforms are multiple variants of proteins generated from individual genes through the alternative splicing process. Each protein isoform is often responsible for the operation of a metabolic reaction. Although multiple protein isoforms generated from one gene can play different functions by having different sets of protein domains and/or subcellular localizations, such information was not properly considered in previous versions of human GEMs.
Upon the initial update of the human GEM, named Recon 2M.1, the research team subsequently implemented a computational framework that systematically generates information on Gene-Transcript-Protein-Reaction Associations (GeTPRA) in order to identify protein isoforms that were previously not identified. This framework was developed in this study. As a result of the implementation of the framework for GeTPRA, more than 11,000 GeTPRA were automatically predicted, and thoroughly validated. Additional metabolic reactions were then added to Recon 2M.1 based on the predicted GeTPRA for the previously uncharacterized protein isoforms; Recon 2M.1 was renamed Recon 2M.2 from this upgrade.
Finally, Recon 2M.2 was integrated with 446 sets of personal biological data (RNA-Seq data) in order to build patient-specific cancer models. These patient-specific cancer models were used to predict cancer metabolism activities and anticancer targets.
The development of a new version of human GEMs along with the computational framework for GeTPRA is expected to boost studies in fundamental human genetics and medicine. Model files of the human GEMs Recon 2M.1 and 2M.2, a full list of the GeTPRA and the source code for the computational framework to predict the GeTPRA are all available as part of the publication of this study.
Distinguished Professor Lee said, “The predicted GeTPRA from the computational framework is expected to serve as a guideline for future experiments on human genetics and biochemistry, whereas the resulting Recon 2M.2 can be used to predict drug targets for various human diseases.”
This work was supported by the Technology Development Program to Solve Climate Changes on Systems Metabolic Engineering for Biorefineries (NRF-2012M1A2A2026556 and NRF-2012M1A2A2026557) from the Ministry of Science and ICT through the National Research Foundation (NRF) of Korea.
(Figure 1:A scheme of Recon 2M.1 development and its use in reconstructing personal genome-scale metabolic models (GEMs). (A) A concept of alternative splicing of human genes and its use in Gene-Transcript-Protein-Reaction Associations (GeTPRA) of Recon 2M.1. (B) A procedure of systematic refinement of the Recon 2Q. Recon 2Q is one of the previously released human GEMs. Biochemically inconsistent reactions include unbalanced, artificial, blocked, and/or redundant reactions. Iterative manual curation was conducted while validating the Recon 2M.1. (C) Reconstruction of cancer patient-specific GEMs using Recon 2M.1 for further simulation studies. In this study, personal biological data (RNA-Seq data) were obtained from The Cancer Genome Atlas (TCGA; https://cancergenome.nih.gov/ ) across the ten cancer types.
(Figure 2: Computational framework for the systematic generation of Gene-Transcript-Protein-Reaction Associations (GeTPRA; red box in the flowchart). Peptide sequences of metabolic genes defined in Recon 2M.1 were retrieved from a database called Ensembl. EC numbers and subcellular localizations of all the protein isoforms of metabolic genes in Recon 2M.1 were predicted using software programs EFICAz2.5 and Wolf PSort, respectively. Information on the newly predicted GeTPRA was systematically incorporated into the Recon 2M.1, thereby resulting in Recon 2M.2.)
2017.10.25 View 8706 -
Sangeun Oh Recognized as a 2017 Google Fellow
Sangeun Oh, a Ph.D. candidate in the School of Computing was selected as a Google PhD Fellow in 2017. He is one of 47 awardees of the Google PhD Fellowship in the world.
The Google PhD Fellowship awards students showing outstanding performance in the field of computer science and related research. Since being established in 2009, the program has provided various benefits, including scholarships worth $10,000 USD and one-to-one research discussion with mentors from Google.
His research work on a mobile system that allows interactions among various kinds of smart devices was recognized in the field of mobile computing. He developed a mobile platform that allows smart devices to share diverse functions, including logins, payments, and sensors. This technology provides numerous user experiences that existing mobile platforms could not offer. Through cross-device functionality sharing, users can utilize multiple smart devices in a more convenient manner. The research was presented at The Annual International Conference on Mobile Systems, Applications, and Services (MobiSys) of the Association for Computing Machinery in July, 2017.
Oh said, “I would like to express my gratitude to my advisor, the professors in the School of Computing, and my lab colleagues. I will devote myself to carrying out more research in order to contribute to society.”
His advisor, Insik Shin, a professor in the School of Computing said, “Being recognized as a Google PhD Fellow is an honor to both the student as well as KAIST. I strongly anticipate and believe that Oh will make the next step by carrying out good quality research.”
2017.09.27 View 10139 -
Photoacoustic Imaging and Photothermal Cancer Therapy Using BR Nanoparticles
(Professor Sangyong Jon and PhD Candidate Dong Yun Lee)
Sangyong Jon, a professor in the Department of Biological Sciences at KAIST, and his team developed combined photoacoustic imaging and photothermal therapy for cancer by using Bilirubin (BR) nanoparticles.
The research team applied the properties of a bile pigment called BR, which exerts potent antioxidant and anti-inflammatory effects, to this research.
The team expects this research, which shows high biocompatibility as well as outstanding photoacoustic imaging and photothermal therapy, to be an appropriate system in the field of treatment for cancer.
In the past, the research team developed a PEGylated bilirubin-based nanoparticle system by combining water-insoluble BR with water-soluble Polyethylene Glycol (PEG).
This technology facilitated BR exerting antioxidants yet prevented them from being accumulated in the body. Its efficiency and safety was identified in an animal disease model, for conditions such as inflammatory bowel disease, islet cell transportation, and asthma.
Differing from previous research methods, this research applied the different physicochemical properties of BR to cancer treatment.
When the causative agent of jaundice, yellow BR, is exposed to a certain wavelength of blue light, the agent becomes a photonic nanomaterial as it responses to the light. This light-responsive nanomaterial can be used to cure jaundice because it allows for active excretion in infants.
Secondly, the team identified that BR is a major component of black pigment gallstones which can be often found in gall bladders or bile ducts under certain pathological conditions. The findings show that BR forms black pigment gallstones without the role of an intermediate or cation, such as calcium and copper. The research team combined cisplatin, a platinum metal-based anticancer drug, with BR so that BR nanoparticles changed the solution color from yellow to purple.
The team also examined the possibility of cisplatin-chelated BR nanoparticles as a probe for photoacoustic images. They found that considerable photoacoustic activity was shown when it was exposed to near infrared light. In fact, the photoacoustic signal was increased significantly in tumors of animals with colorectal cancer when the nanoparticles were administered to it intravenously. The team expects a more accurate diagnosis of tumors through this technology.
Moreover, the team assessed the photothermal effects of cisplatin-chelated BR nanoparticles. The research showed that the temperature of tumors increased by 25 degrees Celsius within five minutes when they were exposed to near infrared light, due to the photothermal effect. After two weeks, their size was reduced compared to that of other groups, and sometimes the tumors were even necrotized.
Professor Jon said, “Existing substances have a low biocompatibility and limitation for clinical therapy because they are artificially oriented; therefore, they might have toxicity. I am hoping that these cisplatin-chelated BR-based nanoparticles will provide a new platform for preclinical, translational research and clinical adaptation of the photoacoustic imaging and photothermal therapy.”
The paper (Dong Yun Lee as a first author) was published online in the renowned journal in the field of applied chemistry, Angewandte Chemi International Edition, on September 4. This research was sponsored by the National Research Foundation of Korea.
(Schematic diagram of the research)
(From left: Bilirubin nanoparticles, cisplatin-chelated Bilirubin nanoparticles)
2017.09.26 View 8107 -
Research Center for Smart Submerged Floating Tunnel Systems Opens
(Distinguished guests including President Shin (fourth from the right) and Director Lee (third from left) at the opening ceremony)
The Research Center for a Smart Submerged Floating Tunnel Systems was recently established at KAIST with the purpose of taking the lead in developing fundamental and applicable technology for submerged floating tunnels as well as fostering creative and talented people. Haeng-Ki Lee, a professor in the Department of Civil & Environmental Engineering at KAIST is heading the center.
KAIST held its opening ceremony on September 7, 2017 in the Applied Engineering Building located on the main campus.
Distinguished guests, including KAIST president Sung-Chul Shin, the President of the Korea Institute of Ocean Science and Technology Gi-Hoon Hong, the President of the Korean Society of Civil Engineering Young-Seok Park, and the Director in the Division of Engineering at the National Research Foundation of Korea Joong-Kon Park attended the ceremony.
The National Research Foundation of Korea provides Engineering Research Center (ERC) projects which find and foster groups with outstanding research performance in a field of engineering. The projects support these groups so that they can strengthen their global competitiveness while enhancing national competence in basic research.
The ‘Research Center for Smart Submerged Floating Tunnel Systems’ was selected as one of the ERC projects in 2017. For the next seven years, the research center will work to develop a submerged floating tunnel system resistant depths greater than 100 meters.
To achieve its goal, the center has defined crucial research topics including: i) a structural analysis program and integrated design technology specific for submerged floating tunnel systems, ii) high-durability marine construction materials and submerged construction integrated systems, and iii) safety and maintenance integrated technology for smart submerged floating tunnel systems.
The ‘Research Center for Smart Submerged Floating Tunnel Systems’ will devote itself to developing a variety of fundamental and applicable technology that will be leading global maritime construction. Moreover, it will concentrate on fostering professional research manpower in related areas.
The Director of the Center Lee said, “The center will cooperate with KAIST researchers who are experts in various fields, including structures, materials, construction, and maritime research. Based on this collaboration, the center will contribute to achieving autonomous technologies by developing fundamental and applicable technology related with submerged floating tunnel systems. It will also take the role of a leading global research hub in the field of submerged floating tunnels as well as construction technologies.”
2017.09.07 View 7872 -
Discovery of an Optimal Drug Combination: Overcoming Resistance to Targeted Drugs for Liver Cancer
A KAIST research team presented a novel method for improving medication treatment for liver cancer using Systems Biology, combining research from information technology and the life sciences. Professor Kwang-Hyun Cho in the Department of Bio and Brain Engineering at KAIST conducted the research in collaboration with Professor Jung-Hwan Yoon in the Department of Internal Medicine at Seoul National University Hospital. This research was published in Hepatology in September 2017 (available online from August 24, 2017).
Liver cancer is the fifth and seventh most common cancer found in men and women throughout the world, which places it second in the cause of cancer deaths. In particular, Korea has 28.4 deaths from liver cancer per 100,000 persons, the highest death rate among OECD countries and twice that of Japan.
Each year in Korea, 16,000 people get liver cancer on average, yet the five-year survival rate stands below 12%. According to the National Cancer Information Center, lung cancer (17,399) took the highest portion of cancer-related deaths, followed by liver cancer (11,311) based on last year data.
Liver cancer is known to carry the highest social cost in comparison to other cancers and it causes the highest fatality in earlier age groups (40s-50s). In that sense, it is necessary to develop a new treatment that mitigates side effects yet elevates the survival rate.
There are ways in which liver cancer can be cured, such as surgery, embolization, and medication treatments; however, the options become limited for curing progressive cancer, a stage in which surgical methods cannot be executed.
Among anticancer medications, Sorafenib, a drug known for enhancing the survival rate of cancer patients, is a unique drug allowed for use as a targeted anticancer medication for progressive liver cancer patients. Its sales reached more than ten billion KRW annually in Korea, but its efficacy works on only about 20% of the treated patients. Also, acquired resistance to Sorafenib is emerging. Additionally, the action mechanism and resistance mechanism of Sorafenib is only vaguely identified.Although Sorafenib only extends the survival rate of terminal cancer patients less than three months on average, it is widely being used because drugs developed by global pharmaceutical companies failed to outperform its effectiveness.
Professor Cho’s research team analyzed the expression changes of genes in cell lines in response to Sorafenib in order to identify the effect and the resistance mechanism of Sorafenib.
As a result, the team discovered the resistance mechanism of Sorafenib using Systems Biology analysis. By combining computer simulations and biological experiments, it was revealed that protein disulfide isomerase (PDI) plays a crucial role in the resistance mechanism of Sorafenib and that its efficacy can be improved significantly by blocking PDI.
The research team used mice in the experiment and discovered the synergic effect of PDI inhibition with Sorafenib for reducing liver cancer cells, known as hepatocellular carcinoma. Also, more PDIs are shown in tissue from patients who possess a resistance to Sorafenib. From these findings, the team could identify the possibility of its clinical applications. The team also confirmed these findings from clinical data through a retrospective cohort study.
“Molecules that play an important role in cell lines are mostly put under complex regulation. For this reason, the existing biological research has a fundamental limitations for discovering its underlying principles,” Professor Cho said. “This research is a representative case of overcoming this limitation of traditional life science research by using a Systems Biology approach, combining IT and life science. It suggests the possibility of developing a new method that overcomes drug resistance with a network analysis of the targeted drug action mechanism of cancer.”
The research was supported by the National Research Foundation of Korea (NRF) and funded by the Ministry of Science and ICT.
(Figure 1. Simulation results from cellular experiments using hepatocellular carcinoma)
(Figure 2. Network analysis and computer simulation by using the endoplasmic reticulum (ER) stress network)
(Figure 3. ER stress network model)
2017.08.30 View 10474 -
The Medici Effect: Highly Flexible, Wearable Displays Born in KAIST
(Ph.D. candidate Seungyeop Choi)
How do you feel when technology you saw in a movie is made into reality? Collaboration between the electrical engineering and textile industries has made TVs or smartphone screens displaying on clothing a reality.
A research team led by Professor Kyung Cheol Choi at the School of Electrical Engineering presented wearable displays for various applications including fashion, IT, and healthcare. Integrating OLED (organic light-emitting diode) into fabrics, the team developed the most highly flexible and reliable technology for wearable displays in the world.
Recently, information displays have become increasingly important as they construct the external part of smart devices for the next generation. As world trends are focusing on the Internet of Things (IoTs) and wearable technology, the team drew a lot of attention by making great progress towards commercializing clothing-shaped ‘wearable displays’.
The research for realizing displays on clothing gained considerable attention from academia as well as industry when research on luminescence formed in fabrics was introduced in 2011; however, there was no technology for commercializing it due to its surface roughness and flexibility.
Because of this technical limitation, clothing-shaped wearable displays were thought to be unreachable technology. However, the KAIST team recently succeeded in developing the world’s most highly efficient, light-emitting clothes that can be commercialized.
The research team used two different approaches, fabric-type and fiber-type, in order to realize clothing-shaped wearable displays. In 2015, the team successfully laminated a thin planarization sheet thermally onto fabric to form a surface that is compatible with the OLEDs approximately 200 hundred nanometers thick. Also, the team reported their research outcomes on enhancing the reliability of operating fiber-based OLEDs. In 2016, the team introduced a dip-coating method, capable of uniformly depositing layers, to develop polymer light-emitting diodes, which show high luminance even on thin fabric.
Based on the research performance in 2015 and 2016, Ph.D. candidate Seungyeop Choi took the lead in the research team and succeeded in realizing fabric-based OLEDs, showing high luminance and efficiency while maintaining the flexibility of the fabric.
The long-term reliability of this wearable device that has the world’s best electrical and optical characteristics was verified through their self-developed, organic and inorganic encapsulation technology. According to the team, their wearable device facilitates the operation of OLEDs even at a bending radius of 2mm.
According to Choi, “Having wavy structures and empty spaces, fiber plays a significant role in lowering the mechanical stress on the OLEDs.”
“Screen displayed on our daily clothing is no longer a future technology,” said Professor Choi. “Light-emitting clothes will have considerable influence on not only the e-textile industry but also the automobile and healthcare industries.”
Moreover, the research team remarked, “It means a lot to realize clothing-shaped OLEDs that have the world’s best luminance and efficiency. It is the most flexible fabric-based light-emitting device among those reported. Moreover, noting that this research carried out an in-depth analysis of the mechanical characteristics of the clothing-spared, light-emitting device, the research performance will become a guideline for developing the fabric-based electronics industry.”
This research was funded by the Ministry of Trade, Industry and Energy and collaborated with KOLON Glotech, INC. The research performance was published in Scientific Reports in July.
(OLEDs operating in fabrics)
(Current-voltage-luminance and efficiency of the highly flexible, fabric-based OLEDs;Image of OLEDs after repetitive bending tests;Verification of flexibility through mechanical simulation)
2017.08.24 View 13851