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Sungryul Yun received the B.S., M.S., and Ph.D. degrees in mechanical engineering from Inha University, Incheon, South Korea, in 2003, 2005, and 2009, respectively. He was a Postdoctoral Fellow in materials science and engineering with the University of California, Los Angeles, Los Angeles, CA, USA, in 2011. He is currently a Senior Research Scientist with the Electronics and Telecommunications Research Institute, Daejeon, South Korea. His research interests include electroactive polymer for flexible functional devices such as physical/chemical sensor, tactile actuator, and tunable lens.
Reversible stress-whitening in a nanocomposite film spontaneously formed from a photocurable PDMS solution enables reliable and real-time monitoring of human motion in the form of a wearable interface.
Seung Koo Park; Sungryul Yun; Geonwoo Hwang; Meejeong Choi; Dong Wook Kim; Jong-Moo Lee; Bong Je Park; SaeKwang Nam; Heeju Mun; Seongcheol Mun; Jeong Mook Lim; Eun Jin Shin; Ki-Uk Kyung; Suntak Park. Highly contrastive, real-time modulation of light intensity by reversible stress-whitening of spontaneously formed nanocomposites: application to wearable strain sensors. Journal of Materials Chemistry C 2021, 1 .
AMA StyleSeung Koo Park, Sungryul Yun, Geonwoo Hwang, Meejeong Choi, Dong Wook Kim, Jong-Moo Lee, Bong Je Park, SaeKwang Nam, Heeju Mun, Seongcheol Mun, Jeong Mook Lim, Eun Jin Shin, Ki-Uk Kyung, Suntak Park. Highly contrastive, real-time modulation of light intensity by reversible stress-whitening of spontaneously formed nanocomposites: application to wearable strain sensors. Journal of Materials Chemistry C. 2021; ():1.
Chicago/Turabian StyleSeung Koo Park; Sungryul Yun; Geonwoo Hwang; Meejeong Choi; Dong Wook Kim; Jong-Moo Lee; Bong Je Park; SaeKwang Nam; Heeju Mun; Seongcheol Mun; Jeong Mook Lim; Eun Jin Shin; Ki-Uk Kyung; Suntak Park. 2021. "Highly contrastive, real-time modulation of light intensity by reversible stress-whitening of spontaneously formed nanocomposites: application to wearable strain sensors." Journal of Materials Chemistry C , no. : 1.
A vibrotactile actuator driven by light energy is developed to produce dynamic stimulations for haptic rendering on a thin-film structure. The actuator is constructed by adopting a thermal bimorph membrane structure of poly(3,4-ethylenedioxythiophene) doped with p-toluenesulfonate (PEDOT-Tos) coated onto a polyethylene terephthalate (PET) film. Upon irradiation of near-infrared (NIR) light, the light energy absorbed at the PEDOT-Tos layer is converted into thermoelastic bending deformation due to the mismatch in coefficient of thermal expansion between PEDOT-Tos and PET. Since the light-induced deformation is reversible, spatially localized, and rapidly controllable with designed light signals, the proposed actuator can produce vibrotactile stimulation over 10 dB at arbitrary areas in the human-sensitive frequency range from 125 to 300 Hz using a low input power of ∼2.6 mW mm–2, as compared with a complex electrical circuit and high input power needed to achieve such actuation performance. Together with its simple structure based on light-driven actuation, the advent of this actuator could open up new ways to achieve substantial advances in rendering textures at a flexible touch interface.
Inwook Hwang; Hyeong Jun Kim; Seongcheol Mun; Sungryul Yun; Tae June Kang. A Light-Driven Vibrotactile Actuator with a Polymer Bimorph Film for Localized Haptic Rendering. ACS Applied Materials & Interfaces 2021, 13, 6597 -6605.
AMA StyleInwook Hwang, Hyeong Jun Kim, Seongcheol Mun, Sungryul Yun, Tae June Kang. A Light-Driven Vibrotactile Actuator with a Polymer Bimorph Film for Localized Haptic Rendering. ACS Applied Materials & Interfaces. 2021; 13 (5):6597-6605.
Chicago/Turabian StyleInwook Hwang; Hyeong Jun Kim; Seongcheol Mun; Sungryul Yun; Tae June Kang. 2021. "A Light-Driven Vibrotactile Actuator with a Polymer Bimorph Film for Localized Haptic Rendering." ACS Applied Materials & Interfaces 13, no. 5: 6597-6605.
Poly(dimethylsiloxane) (PDMS) has been extensively used as an electroactive polymer material because it exhibits not only excellent moldability but also mechanical properties sufficient enough for electroactive performance despite low dielectric permittivity. Its low dielectric property is due to its molecular non-polarity. Here, we introduce a polar group into a PDMS elastomer by using vinyl acetate (VAc) as a crosslinker to improve the dielectric permittivity. We synthesized a high-molecular weight PDMS copolymer containing vinyl groups, namely poly(dimethylsiloxane-co-methylvinylsiloxane) (VPDMS), and prepared several of the VPDMS solutions in VAc. We obtained transparent PDMS films by UV curing of the solution layers. Electromechanical actuation-related physical properties of one of the UV-cured films were almost equivalent to or superior to those of platinum-catalyzed hydrosilylation-cured PDMS films. In addition, saponification of the UV-cured film significantly improved the electrical and mechanical properties (ɛ′ ~ 44.1 pF/m at 10 kHz, E ~ 350 kPa, ɛ ~ 320%). The chemical introduction of VAc into PDMS main chains followed by saponification would offer an efficacious method of enhancing the electroactive properties of PDMS elastomers.
Seung Koo Park; Meejeong Choi; Dong Wook Kim; Bong Je Park; Eun Jin Shin; Suntak Park; Sungryul Yun. Dielectric Elastomers UV-Cured from Poly(dimethylsiloxane) Solution in Vinyl Acetate. Polymers 2020, 12, 2660 .
AMA StyleSeung Koo Park, Meejeong Choi, Dong Wook Kim, Bong Je Park, Eun Jin Shin, Suntak Park, Sungryul Yun. Dielectric Elastomers UV-Cured from Poly(dimethylsiloxane) Solution in Vinyl Acetate. Polymers. 2020; 12 (11):2660.
Chicago/Turabian StyleSeung Koo Park; Meejeong Choi; Dong Wook Kim; Bong Je Park; Eun Jin Shin; Suntak Park; Sungryul Yun. 2020. "Dielectric Elastomers UV-Cured from Poly(dimethylsiloxane) Solution in Vinyl Acetate." Polymers 12, no. 11: 2660.
We propose a monolithic focus-tunable lens structure based on the dielectric-elastomer actuator (DEA) technology. In our focus-tunable lens, a soft lens and radial in-plane actuator mimicking the ocular focal-tuning mechanism are constructed in a single body of an optimized dielectric-elastomer film. We provide device fabrication methods including elastomer synthesis, structure formation, and packaging process steps. Performance test measurements show 93% focal tunability and 7 ms response time under static and dynamic electrical driving conditions, respectively. These performance characteristics are substantially enhanced from the previous polylithic DEA tunable lens by a factor 1.4 for the focal tunability and a factor 9.4 for the dynamic tuning-speed limit. Therefore, we obtain greatly enhanced focal tuning control in a remarkably simple and compact device structure.
Bong Je Park; Suntak Park; Meejeong Choi; Seung Koo Park; Sungryul Yun; Eunjin Shin; Jae Woong Yoon. Monolithic focus-tunable lens technology enabled by disk-type dielectric-elastomer actuators. Scientific Reports 2020, 10, 1 -6.
AMA StyleBong Je Park, Suntak Park, Meejeong Choi, Seung Koo Park, Sungryul Yun, Eunjin Shin, Jae Woong Yoon. Monolithic focus-tunable lens technology enabled by disk-type dielectric-elastomer actuators. Scientific Reports. 2020; 10 (1):1-6.
Chicago/Turabian StyleBong Je Park; Suntak Park; Meejeong Choi; Seung Koo Park; Sungryul Yun; Eunjin Shin; Jae Woong Yoon. 2020. "Monolithic focus-tunable lens technology enabled by disk-type dielectric-elastomer actuators." Scientific Reports 10, no. 1: 1-6.
Crosslinked poly(dimethylsiloxane) (PDMS) has been widely used as a dielectric elastomer for electrically driven actuators because it exhibits high elasticity, low initial modulus, and excellent moldability in spite of low dielectric constant. However, further improvement in the characteristics of the PDMS elastomer is not easy due to its chemical non-reactivity. Here, we report a simple method for functionalizing the elastomer by varying content of hydridosilyl groups in PDMS acted as a crosslinker. We synthesized poly(dimethylsiloxane-co-methylvinylsiloxane) (VPDMS) and poly(dimethylsiloxane-co-methylsiloxane) (HPDMS). Tri(ethylene glycol) divinyl ether (TEGDE) as a polar molecule was added to the mixture of VPDMS and HPDMS. TEGDE was reacted to the hydridosilyl group in HPDMS during crosslinking between VPDMS and HPDMS in the presence of platinum as a catalyst. Permittivity of the crosslinked film increased from ca. 25 to 36 pF/m at 10 kHz without a decline in other physical properties such as transparency and elasticity (T > 85%, E ~150 kPa, ɛ ~270%). It depends on the hydridosilyl group content of HPDMS. The chemical introduction of a new molecule into the hydridosilyl group in HPDMS during crosslinking would provide a facile, effective method of modifying the PDMS elastomers.
Seung Koo Park; Bong Je Park; Mee Jeong Choi; Dong Wook Kim; Jae Woong Yoon; Eun Jin Shin; Sungryul Yun; Suntak Park. Facile Functionalization of Poly(Dimethylsiloxane) Elastomer by Varying Content of Hydridosilyl Groups in a Crosslinker. Polymers 2019, 11, 1842 .
AMA StyleSeung Koo Park, Bong Je Park, Mee Jeong Choi, Dong Wook Kim, Jae Woong Yoon, Eun Jin Shin, Sungryul Yun, Suntak Park. Facile Functionalization of Poly(Dimethylsiloxane) Elastomer by Varying Content of Hydridosilyl Groups in a Crosslinker. Polymers. 2019; 11 (11):1842.
Chicago/Turabian StyleSeung Koo Park; Bong Je Park; Mee Jeong Choi; Dong Wook Kim; Jae Woong Yoon; Eun Jin Shin; Sungryul Yun; Suntak Park. 2019. "Facile Functionalization of Poly(Dimethylsiloxane) Elastomer by Varying Content of Hydridosilyl Groups in a Crosslinker." Polymers 11, no. 11: 1842.
We developed an improved version of midair visuohaptic virtual piano utilizing multiple ultrasonic array modules. We implemented scheduling algorithm for simultaneous generation of haptic points to increase the output efficiency. Our algorithm is based on temporal switching of modulated ultrasonic signals and player draft system on multiple ultrasonic modules. With the extended AirPiano, a user can play the virtual piano in a scene shown via the HMD and can feel the haptic points on their whole fingers while touching the keys.
Inwook Hwang; Sungryul Yun. Extended AirPiano: Visuohaptic Virtual Piano with Multiple Ultrasonic Array Modules. Lecture Notes in Electrical Engineering 2019, 313 -316.
AMA StyleInwook Hwang, Sungryul Yun. Extended AirPiano: Visuohaptic Virtual Piano with Multiple Ultrasonic Array Modules. Lecture Notes in Electrical Engineering. 2019; ():313-316.
Chicago/Turabian StyleInwook Hwang; Sungryul Yun. 2019. "Extended AirPiano: Visuohaptic Virtual Piano with Multiple Ultrasonic Array Modules." Lecture Notes in Electrical Engineering , no. : 313-316.
Developing tunable lenses, an expansion-based mechanism for dynamic focus adjustment can provide a larger focal length tuning range than a contraction-based mechanism. Here, we develop an expansion-tunable soft lens module using a disk-type dielectric elastomer actuator (DEA) that creates axially symmetric pulling forces on a soft lens. Adopted from a biological accommodation mechanism in human eyes, a soft lens at the annular center of a disk-type DEA pair is efficiently stretched to change the focal length in a highly reliable manner. A soft lens with a diameter of 3 mm shows a 65.7% change in the focal length (14.3-23.7 mm) under a dynamic driving voltage signal control. We confirm a quadratic relation between lens expansion and focal length that leads to large focal length tunability obtainable in the proposed approach. The fabricated tunable lens module can be used for soft, lightweight, and compact vision components in robots, drones, vehicles, and so on.
SaeKwang Nam; Sungryul Yun; Jae Woong Yoon; Suntak Park; Seung Koo Park; Seongcheol Mun; Bongje Park; Ki-Uk Kyung. A Robust Soft Lens for Tunable Camera Application Using Dielectric Elastomer Actuators. Soft Robotics 2018, 5, 777 -782.
AMA StyleSaeKwang Nam, Sungryul Yun, Jae Woong Yoon, Suntak Park, Seung Koo Park, Seongcheol Mun, Bongje Park, Ki-Uk Kyung. A Robust Soft Lens for Tunable Camera Application Using Dielectric Elastomer Actuators. Soft Robotics. 2018; 5 (6):777-782.
Chicago/Turabian StyleSaeKwang Nam; Sungryul Yun; Jae Woong Yoon; Suntak Park; Seung Koo Park; Seongcheol Mun; Bongje Park; Ki-Uk Kyung. 2018. "A Robust Soft Lens for Tunable Camera Application Using Dielectric Elastomer Actuators." Soft Robotics 5, no. 6: 777-782.
We report a pitch-tuned coiled polymer actuator (CPA) with a compliant silver-nanowires (AgNWs) electrode. For a pitch-tuning of the CPA, we sequentially implement a twist-insertion for coiling a nylon-6 fiber, mechanical pre-stretching, and a couple of thermal treatments. When heated under a light-loading, the pitch-tuned CPA can produce a contractile strain far beyond the original one with a limited space to contract. Since the silver-nanowires electrode established on the coiled structure retains a fairly consistent electrical property allowing repetitive Joule-heating under a large uniaxial elongation with loading, the synergetic benefits from pitch-tuning and adopting the AgNWs as a Joule-heating electrode enables the CPA to produce electrically-controllable and large contractile strain under a light-loading that can be utilized for an artificial muscle of soft micro-robot.
Dongbum Pyo; Jeong-Mook Lim; Seongcheol Mun; Sungryul Yun. Silver-Nanowires Coated Pitch-Tuned Coiled Polymer Actuator for Large Contractile Strain under Light-Loading. International Journal of Precision Engineering and Manufacturing 2018, 19, 1895 -1900.
AMA StyleDongbum Pyo, Jeong-Mook Lim, Seongcheol Mun, Sungryul Yun. Silver-Nanowires Coated Pitch-Tuned Coiled Polymer Actuator for Large Contractile Strain under Light-Loading. International Journal of Precision Engineering and Manufacturing. 2018; 19 (12):1895-1900.
Chicago/Turabian StyleDongbum Pyo; Jeong-Mook Lim; Seongcheol Mun; Sungryul Yun. 2018. "Silver-Nanowires Coated Pitch-Tuned Coiled Polymer Actuator for Large Contractile Strain under Light-Loading." International Journal of Precision Engineering and Manufacturing 19, no. 12: 1895-1900.
We demonstrate a pitch-tuned coiled polymer actuator that can produce a large thermally-induced-contractile-strain under a light-loading. For a pitch-tuning of the coiled polymer actuator (CPA), we sequentially implement a twist-insertion for coiling a nylon-6 fiber, mechanical pre-stretching, and a couple of thermal treatments. By adopting our pitch-tuning methodology, geometric structure of the original CPA can be consistently modulated with a pre-stretching ratio. When heated under a light-loading, the pitch-tuned CPA can produce a contractile strain far beyond the original CPA with a limited space to contract. Due to the benefit, pitch-tuning for the CPA can open an opportunity to utilize the CPA as an artificial muscle for soft micro-robot.
Jeong Mook Lim; Dongbum Pyo; Sungryul Yun. Pitch-tuned coiled polymer actuator for large contractile strain under light-loading. 2018 International Conference on Information and Communication Technology Convergence (ICTC) 2018, 1152 -1154.
AMA StyleJeong Mook Lim, Dongbum Pyo, Sungryul Yun. Pitch-tuned coiled polymer actuator for large contractile strain under light-loading. 2018 International Conference on Information and Communication Technology Convergence (ICTC). 2018; ():1152-1154.
Chicago/Turabian StyleJeong Mook Lim; Dongbum Pyo; Sungryul Yun. 2018. "Pitch-tuned coiled polymer actuator for large contractile strain under light-loading." 2018 International Conference on Information and Communication Technology Convergence (ICTC) , no. : 1152-1154.
We propose an elastomer thin-film pressure sensor enabled by pressure-sensitive optical signals through vertical photonic tunnel-junction couplers. We provide the operation principle, design, fabrication, and test results from a 50 μm thick polydimethylsiloxane sheet accommodating embedded vertical photonic tunnel-junction couplers. The result with a 5 mm long device shows a differential optical power change that is ∼140% of the incident power under moderate external pressure of ∼40 kPa, thereby clearly demonstrating a robust pressure-sensing capability realized in a highly flexible, lightweight, transferrable, optically transparent, and bio-compatible thin-film material. Therefore, the proposed approach potentially enables versatile pressure and touch sensors for many applications in practice.
Jae Woong Yoon; Jin Tae Kim; Bong Je Park; Sungryul Yun; Seongcheol Mun; Seung Koo Park; Suntak Park. Elastomer thin-film pressure sensor based on embedded photonic tunnel-junction arrays. Optics Letters 2018, 43, 3953 -3956.
AMA StyleJae Woong Yoon, Jin Tae Kim, Bong Je Park, Sungryul Yun, Seongcheol Mun, Seung Koo Park, Suntak Park. Elastomer thin-film pressure sensor based on embedded photonic tunnel-junction arrays. Optics Letters. 2018; 43 (16):3953-3956.
Chicago/Turabian StyleJae Woong Yoon; Jin Tae Kim; Bong Je Park; Sungryul Yun; Seongcheol Mun; Seung Koo Park; Suntak Park. 2018. "Elastomer thin-film pressure sensor based on embedded photonic tunnel-junction arrays." Optics Letters 43, no. 16: 3953-3956.
In this paper, we propose a soft vibrotactile actuator made by mixing silicon dioxide (SiO 2 ) nanoparticles and plasticized PVC gel. The effect of the silicon dioxide nanoparticles in the plasticized PVC gel for the haptic performance is investigated in terms of electric, dielectric, and mechanical properties. Furthermore, eight soft vibrotactile actuators are prepared as a function of the SiO 2 content. Experiments are conducted to examine the haptic performance of the prepared eight soft vibrotactile actuators and to find the best weight ratio of the plasticized PVC gel to the SiO 2 nanoparticles. The experiments should show that the plasticized PVC gel with silicon dioxide nanoparticles improves the haptic performance of the plasticized PVC gel-based vibrotactile actuator, and the proposed vibrotactile actuator can create a variety of haptic sensations in a wide frequency range.
Won-Hyeong Park; Eun-Jae Shin; Sungryul Yun; Sang-Youn Kim. An Enhanced Soft Vibrotactile Actuator Based on ePVC Gel with Silicon Dioxide Nanoparticles. IEEE Transactions on Haptics 2018, 11, 22 -29.
AMA StyleWon-Hyeong Park, Eun-Jae Shin, Sungryul Yun, Sang-Youn Kim. An Enhanced Soft Vibrotactile Actuator Based on ePVC Gel with Silicon Dioxide Nanoparticles. IEEE Transactions on Haptics. 2018; 11 (1):22-29.
Chicago/Turabian StyleWon-Hyeong Park; Eun-Jae Shin; Sungryul Yun; Sang-Youn Kim. 2018. "An Enhanced Soft Vibrotactile Actuator Based on ePVC Gel with Silicon Dioxide Nanoparticles." IEEE Transactions on Haptics 11, no. 1: 22-29.
This paper reports soft actuator based tactile stimulation interfaces applicable to wearable devices. The soft actuator is prepared by multi-layered accumulation of thin electro-active polymer (EAP) films. The multi-layered actuator is designed to produce electrically-induced convex protrusive deformation, which can be dynamically programmable for wide range of tactile stimuli. The maximum vertical protrusion is 650 μm and the output force is up to 255 mN. The soft actuators are embedded into the fingertip part of a glove and front part of a forearm band, respectively. We have conducted two kinds of experiments with 15 subjects. Perceived magnitudes of actuators protrusion and vibrotactile intensity were measured with frequency of 1 Hz and 191 Hz, respectively. Analysis of the user tests shows participants perceive variation of protrusion height at the finger pad and modulation of vibration intensity through the proposed soft actuator based tactile interface.
Seongcheol Mun; Sungryul Yun; SaeKwang Nam; Seung Koo Park; Suntak Park; Bong Je Park; Jeong Mook Lim; Ki-Uk Kyung. Electro-Active Polymer Based Soft Tactile Interface for Wearable Devices. IEEE Transactions on Haptics 2018, 11, 15 -21.
AMA StyleSeongcheol Mun, Sungryul Yun, SaeKwang Nam, Seung Koo Park, Suntak Park, Bong Je Park, Jeong Mook Lim, Ki-Uk Kyung. Electro-Active Polymer Based Soft Tactile Interface for Wearable Devices. IEEE Transactions on Haptics. 2018; 11 (1):15-21.
Chicago/Turabian StyleSeongcheol Mun; Sungryul Yun; SaeKwang Nam; Seung Koo Park; Suntak Park; Bong Je Park; Jeong Mook Lim; Ki-Uk Kyung. 2018. "Electro-Active Polymer Based Soft Tactile Interface for Wearable Devices." IEEE Transactions on Haptics 11, no. 1: 15-21.
We demonstrate a robust flexible tactile actuator that is capable of working under high external pressures. The tactile actuator is based on a pyramidal microstructured dielectric elastomer layer inducing variation in both mechanical and dielectric properties. The vibrational performance of the actuator can be modulated by changing the geometric parameter of the microstructures. We evaluated the performance of the actuator under high-pressure loads up to 25 kPa, which is over the typical range of pressure applied when humans touch or manipulate objects. Due to the benefit of nonlinearity of the pyramidal structure, the actuator could maintain high mechanical output under various external pressures in the frequency range of 100–200 Hz, which is the most sensitive to vibration acceleration for human finger pads. The responses are not only fast, reversible, and highly durable under consecutive cyclic operations, but also large enough to impart perceivable vibrations for haptic feedback on practical wearable device applications.
Dongbum Pyo; Semin Ryu; Ki-Uk Kyung; Sungryul Yun; Dong-Soo Kwon. High-pressure endurable flexible tactile actuator based on microstructured dielectric elastomer. Applied Physics Letters 2018, 112, 061902 .
AMA StyleDongbum Pyo, Semin Ryu, Ki-Uk Kyung, Sungryul Yun, Dong-Soo Kwon. High-pressure endurable flexible tactile actuator based on microstructured dielectric elastomer. Applied Physics Letters. 2018; 112 (6):061902.
Chicago/Turabian StyleDongbum Pyo; Semin Ryu; Ki-Uk Kyung; Sungryul Yun; Dong-Soo Kwon. 2018. "High-pressure endurable flexible tactile actuator based on microstructured dielectric elastomer." Applied Physics Letters 112, no. 6: 061902.
We propose and demonstrate an all-solid-state tunable binary phase Fresnel lens with electrically controllable focal length. The lens is composed of a binary phase Fresnel zone plate, a circular acrylic frame, and a dielectric elastomer (DE) actuator which is made of a thin DE layer and two compliant electrodes using silver nanowires. Under electric potential, the actuator produces in-plane deformation in a radial direction that can compress the Fresnel zones. The electrically-induced deformation compresses the Fresnel zones to be contracted as high as 9.1% and changes the focal length, getting shorter from 20.0 cm to 14.5 cm. The measured change in the focal length of the fabricated lens is consistent with the result estimated from numerical simulation.
Suntak Park; Bongje Park; SaeKwang Nam; Sungryul Yun; Seung Koo Park; Seongcheol Mun; Jeong Mook Lim; Yeonghwa Ryu; Seok Ho Song; Ki-Uk Kyung. Electrically tunable binary phase Fresnel lens based on a dielectric elastomer actuator. Optics Express 2017, 25, 23801 -23808.
AMA StyleSuntak Park, Bongje Park, SaeKwang Nam, Sungryul Yun, Seung Koo Park, Seongcheol Mun, Jeong Mook Lim, Yeonghwa Ryu, Seok Ho Song, Ki-Uk Kyung. Electrically tunable binary phase Fresnel lens based on a dielectric elastomer actuator. Optics Express. 2017; 25 (20):23801-23808.
Chicago/Turabian StyleSuntak Park; Bongje Park; SaeKwang Nam; Sungryul Yun; Seung Koo Park; Seongcheol Mun; Jeong Mook Lim; Yeonghwa Ryu; Seok Ho Song; Ki-Uk Kyung. 2017. "Electrically tunable binary phase Fresnel lens based on a dielectric elastomer actuator." Optics Express 25, no. 20: 23801-23808.
We demonstrate an initial progress prototype toward a surface morphable tactile interface. The surface is composed of thin film type electro-active material (EAP) and its initial shape is maintained to be a flat membrane. Surface of the membrane is designed to be protrusive by electric field. The height of the protrusion and transition speed of the shape change would be controllable by amplitude and frequency of driving signals.
Seongcheol Mun; Sungryul Yun; SaeKwang Nam; Seung-Koo Park; Ki-Uk Kyung. Initial Progress Toward a Surface Morphable Tactile Interface. Lecture Notes in Electrical Engineering 2017, 432, 113 -114.
AMA StyleSeongcheol Mun, Sungryul Yun, SaeKwang Nam, Seung-Koo Park, Ki-Uk Kyung. Initial Progress Toward a Surface Morphable Tactile Interface. Lecture Notes in Electrical Engineering. 2017; 432 ():113-114.
Chicago/Turabian StyleSeongcheol Mun; Sungryul Yun; SaeKwang Nam; Seung-Koo Park; Ki-Uk Kyung. 2017. "Initial Progress Toward a Surface Morphable Tactile Interface." Lecture Notes in Electrical Engineering 432, no. : 113-114.
Seung Koo Park; Young-Je Kwark; SaeKwang Nam; Jaehyun Moon; Dong Wook Kim; Suntak Park; Bongje Park; Sungryul Yun; Jeong-Ik Lee; Byounggon Yu; Ki-Uk Kyung. A variation in wrinkle structures of UV-cured films with chemical structures of prepolymers. Materials Letters 2017, 199, 105 -109.
AMA StyleSeung Koo Park, Young-Je Kwark, SaeKwang Nam, Jaehyun Moon, Dong Wook Kim, Suntak Park, Bongje Park, Sungryul Yun, Jeong-Ik Lee, Byounggon Yu, Ki-Uk Kyung. A variation in wrinkle structures of UV-cured films with chemical structures of prepolymers. Materials Letters. 2017; 199 ():105-109.
Chicago/Turabian StyleSeung Koo Park; Young-Je Kwark; SaeKwang Nam; Jaehyun Moon; Dong Wook Kim; Suntak Park; Bongje Park; Sungryul Yun; Jeong-Ik Lee; Byounggon Yu; Ki-Uk Kyung. 2017. "A variation in wrinkle structures of UV-cured films with chemical structures of prepolymers." Materials Letters 199, no. : 105-109.
We demonstrate a polymer-based active-lens module allowing a dynamic focus controllable optical system with a wide tunable range. The active-lens module is composed of parallelized two active-lenses with a convex and a concave shaped hemispherical lens structure, respectively. Under operation with dynamic input voltage signals, each active-lens produces translational movement bi-directionally responding to a hybrid driving force that is a combination of an electro-active response of a thin dielectric elastomer membrane and an electro-static attraction force. Since the proposed active lens module widely modulates a gap-distance between lens-elements, an optical system based on the active-lens module provides widely-variable focusing for selective imaging of objects in arbitrary position.
Sungryul Yun; Suntak Park; SaeKwang Nam; Bongje Park; Seung Koo Park; Seongcheol Mun; Jeong Mook Lim; Ki-Uk Kyung. An electro-active polymer based lens module for dynamically varying focal system. Applied Physics Letters 2016, 109, 141908 .
AMA StyleSungryul Yun, Suntak Park, SaeKwang Nam, Bongje Park, Seung Koo Park, Seongcheol Mun, Jeong Mook Lim, Ki-Uk Kyung. An electro-active polymer based lens module for dynamically varying focal system. Applied Physics Letters. 2016; 109 (14):141908.
Chicago/Turabian StyleSungryul Yun; Suntak Park; SaeKwang Nam; Bongje Park; Seung Koo Park; Seongcheol Mun; Jeong Mook Lim; Ki-Uk Kyung. 2016. "An electro-active polymer based lens module for dynamically varying focal system." Applied Physics Letters 109, no. 14: 141908.
Seung Koo Park; Young-Je Kwark; SaeKwang Nam; Suntak Park; Bongje Park; Sungryul Yun; Jaehyun Moon; Jeong-Ik Lee; Byounggon Yu; Ki-Uk Kyung. Wrinkle structures formed by formulating UV-crosslinkable liquid prepolymers. Polymer 2016, 99, 447 -452.
AMA StyleSeung Koo Park, Young-Je Kwark, SaeKwang Nam, Suntak Park, Bongje Park, Sungryul Yun, Jaehyun Moon, Jeong-Ik Lee, Byounggon Yu, Ki-Uk Kyung. Wrinkle structures formed by formulating UV-crosslinkable liquid prepolymers. Polymer. 2016; 99 ():447-452.
Chicago/Turabian StyleSeung Koo Park; Young-Je Kwark; SaeKwang Nam; Suntak Park; Bongje Park; Sungryul Yun; Jaehyun Moon; Jeong-Ik Lee; Byounggon Yu; Ki-Uk Kyung. 2016. "Wrinkle structures formed by formulating UV-crosslinkable liquid prepolymers." Polymer 99, no. : 447-452.
In this paper, we report on mechanical and electrical properties of the stretchable strain sensor based on two-dimensional network of silver nanowires embedded between bio-compatible polydimethylsiloxane films. Our strain sensor shows a quasi-linear response of resistance change with respect to stretching up to 15%. Dynamic stability and durability of the strain sensor are investigated through cyclic stretching test (1,000 times). We also demonstrate sensitivity of our strain sensor under the pulse-type stresses with arbitrary intensities.
W. G Song; S Yun; K Kyung; M Kim; J Lee; J Baek; S Kim; Y. K Hong; Song; W. G; Yun S; Kyung K; Kim M; Lee J. Sensitive and Stretchable Strain Sensors Based on Silver Nanowires Network. Journal of Nanoscience and Nanotechnology 2016, 16, 8614 -8617.
AMA StyleW. G Song, S Yun, K Kyung, M Kim, J Lee, J Baek, S Kim, Y. K Hong, Song, W. G, Yun S, Kyung K, Kim M, Lee J. Sensitive and Stretchable Strain Sensors Based on Silver Nanowires Network. Journal of Nanoscience and Nanotechnology. 2016; 16 (8):8614-8617.
Chicago/Turabian StyleW. G Song; S Yun; K Kyung; M Kim; J Lee; J Baek; S Kim; Y. K Hong; Song; W. G; Yun S; Kyung K; Kim M; Lee J. 2016. "Sensitive and Stretchable Strain Sensors Based on Silver Nanowires Network." Journal of Nanoscience and Nanotechnology 16, no. 8: 8614-8617.
Transition metal dichalcogenides (TMDs) layers of molecular thickness, in particular molybdenum disulfide (MoS2), become increasingly important as active elements for mechanically flexible/stretchable electronics owing to their relatively high carrier mobility, wide bandgap, and mechanical flexibility. Although the superior electronic properties of TMD transistors are usually integrated into rigid silicon wafers or glass substrates, the achievement of similar device performance on flexible substrates remains quite a challenge. The present work successfully addresses this challenge by a novel process architecture consisting of a solution‐based polyimide (PI) flexible substrate in which laser‐welded silver nanowires are embedded, a hybrid organic/inorganic gate insulator, and multilayers of MoS2. Transistors fabricated according to this process scheme have decent properties: a field‐effect‐mobility as high as 141 cm2 V−1 s−1 and an Ion/Ioff ratio as high as 5 × 105. Furthermore, no apparent degradation in the device properties is observed under systematic cyclic bending tests with bending radii of 10 and 5 mm. Overall electrical and mechanical results provide potentially important applications in the fabrication of versatile areas of flexible integrated circuitry.
Won Geun Song; Hyuk-Jun Kwon; Jozeph Park; Junyeob Yeo; Minjeong Kim; Suntak Park; Sungryul Yun; Ki-Uk Kyung; Costas Grigoropoulos; SunKook Kim; Young Ki Hong. High-Performance Flexible Multilayer MoS2Transistors on Solution-Based Polyimide Substrates. Advanced Functional Materials 2016, 26, 2426 -2434.
AMA StyleWon Geun Song, Hyuk-Jun Kwon, Jozeph Park, Junyeob Yeo, Minjeong Kim, Suntak Park, Sungryul Yun, Ki-Uk Kyung, Costas Grigoropoulos, SunKook Kim, Young Ki Hong. High-Performance Flexible Multilayer MoS2Transistors on Solution-Based Polyimide Substrates. Advanced Functional Materials. 2016; 26 (15):2426-2434.
Chicago/Turabian StyleWon Geun Song; Hyuk-Jun Kwon; Jozeph Park; Junyeob Yeo; Minjeong Kim; Suntak Park; Sungryul Yun; Ki-Uk Kyung; Costas Grigoropoulos; SunKook Kim; Young Ki Hong. 2016. "High-Performance Flexible Multilayer MoS2Transistors on Solution-Based Polyimide Substrates." Advanced Functional Materials 26, no. 15: 2426-2434.