Quantum Efficiency Improvement of Green PHOLEDs with Ir(ppy)₃

Hyuntaek Woo,Byoungdeog Choi 한국진공학회 2020 한국진공학회 학술발표회초록집 Vol.2020 No.2

Asymmetric leakage current characteristics of ZrO₂/Al₂O₃/ZrO₂ capacitors

Hyuntaek Woo,Byoungdeog Choi 한국진공학회 2020 한국진공학회 학술발표회초록집 Vol.2020 No.8

The effect of silicon incorporation on electrical characteristics of solution-processed Indium-Zinc oxide thin film transistor

Hyuntaek Woo,Byoungdeog Choi 한국진공학회 2021 한국진공학회 학술발표회초록집 Vol.2021 No.2

We observed electrical characteristics of IZO TFT with silicon. The activation layer was formed by a spin-coating method. The value of on/off ratio increased from 1.6 × 10³ to 2.4 × 10⁴, S.S. decreased from 2.69 V/dec to 0.43 V/dec, and V_T shifted positive from -2.04 V to -1.15 V as the molar ratio of silicon in IZO films increased. Silicon has not only larger electronegativity and but also higher metallic bonding energy with oxygen than Indium and Zinc. This means that the electrical characteristics of the TFT can be improved by incorporating silicon in the IZO activation layer.

Charging Compensation Layer on Polyimide for Enhanced Device Stability in Flexible Technology

Hyojung Kim,Jongwoo Park,Jungmin Park,Hyuntaek Woo,Jongyoon Lee,Yoonsoo Park,Taeyoung Khim,Junehwan Kim,Jaeseob Lee,Jangkun Song,Byoungdeog Choi 대한금속·재료학회 2021 ELECTRONIC MATERIALS LETTERS Vol.17 No.3

In this paper, we propose a structure that prevents the charging eff ects that occur in devices fabricated on polyimide (PI)substrates. In general, when fabricating a device on a PI substrate, an inorganic barrier layer is fi rst deposited to preventpenetration of oxygen and moisture. In this study, we confi rmed that fl uorine ions were induced from PI by bias stress andproposed a SiOCH/SiO 2 double layer as a barrier to prevent charging. Then, Al/PI/SiO 2 /Al and Al/ PI/SiOCH/SiO 2 /Al metal–insulator–metal capacitors were manufactured. The capacitor characteristics before and after application of bias stress wereverifi ed through current–voltage (I–V) and capacitance–voltage (C–V), which are electrical characterization methods, andsecondary ion mass spectrometry (SIMS), which is a physical analysis method. As the voltage increased, the capacitance andcurrent of the Al/PI/SiO 2 /Al capacitor varied, but those of the Al/PI/SiOCH/SiO 2 /Al device did not change. Finally, SIMSanalysis confi rmed that the PI-derived fl uorine ions replaced the Si–CH 3 bonds within the SiOCH fi lm with Si–F bonds,thereby preventing capacitance and current fl uctuations.

뇌기반 3D 가상환경 멀미 경감 솔루션 개발

한경훈(Han, Kyunghun),박창훈(Park, Changhoon),김응석(Kim, Eungseok),김대근(Kim, Daeguen),우성호(Woo, Sungho),김현택(Kim Hyuntaek) 한국문화산업학회 2011 문화산업연구 Vol.11 No.2

Several studies indicated that a rest frame reduced cybersickness, especially the vection induced sickness, associated with exposure to real 3D virtual environments. The form and the way realizing the rest frame in 3D virtual environments have different effects on immersion, presence and reducing cybersickness. Therefore it is important to find the most effective form and method realizing a rest frame in 3D virtual environments reducing cybersickness while at the same time maintaining presence and immersion. In this study, we realized a 3D rectangulartunnel rest frame and a real 3D virtual environment inducing cybersickness. For verifying the rest frame’s effect of reducing cybersickness, 10 subjects were exposed to both rest and nonrest conditions after an interval of three days after the real 3D virtual environment. We recorded electrogastrogram, skin conductance, heart rate, and respiration during the exposure to 3D virtual environment. Simulator sickness questionnaire(SSQ) was used for measuring the intensity of the sickness before and after the exposure. The results showed that the scores of SSQ were not reduced significantly by using the rest frame. All 4 electrophysiological responses were not changed significantly from the baseline period to the exposure of 3D virtual environment in the rest frame condition compared to the nonrest frame condition. The results suggest that 3D rectangulartunnel rest frame is not an adapted rest frame for reducing cybersickness in real 3D virtual environments. Several studies indicated that a rest frame reduced cybersickness, especially the vection induced sickness, associated with exposure to real 3D virtual environments. The form and the way realizing the rest frame in 3D virtual environments have different effects on immersion, presence and reducing cybersickness. Therefore it is important to find the most effective form and method realizing a rest frame in 3D virtual environments reducing cybersickness while at the same time maintaining presence and immersion. In this study, we realized a 3D rectangulartunnel rest frame and a real 3D virtual environment inducing cybersickness. For verifying the rest frame’s effect of reducing cybersickness, 10 subjects were exposed to both rest and nonrest conditions after an interval of three days after the real 3D virtual environment. We recorded electrogastrogram, skin conductance, heart rate, and respiration during the exposure to 3D virtual environment. Simulator sickness questionnaire(SSQ) was used for measuring the intensity of the sickness before and after the exposure. The results showed that the scores of SSQ were not reduced significantly by using the rest frame. All 4 electrophysiological responses were not changed significantly from the baseline period to the exposure of 3D virtual environment in the rest frame condition compared to the nonrest frame condition. The results suggest that 3D rectangulartunnel rest frame is not an adapted rest frame for reducing cybersickness in real 3D virtual environments.

뇌기반 3D 가상환경 멀미 경감 솔루션 개발

한경훈(KyungHun HAN),박창훈(ChangHoon Park),김응석(EungSeok Kim),김대근(DaeGuen Kim),우성호(SungHo Woo),김현택(HyunTaek Kim) 한국문화산업학회 2011 한국문화산업학회 학술대회 Vol.2011 No.6

실사와 흡사한 현실을 구현할 수 있다는 장점으로 산업, 의료, 및 파일럿의 비행훈련 등에 널리 사용되었던 3D 가상 환경은 3D 영상 미디어의 기술 발달과 함께 이제는 우리 생활 안에 생활 가전 그리고 일상 엔터테인먼트로 자리 잡고있다. 그러나 아직까지 3D 가상환경 부작용인 사이버멀미가 3D영상 미디어 산업 발전에 제약이 되고 있어 사이버멀미 경감 솔루션 개발이 필요하다. 정지좌표계(rest frame)는 가상환경에서 멀미를 유발시키는 vection 효과를 줄이는 효과를 가지고 있다. 그러나 3D 가상환경에서 정지좌표계의 구현 방법과 형태에 따라 가상환경의 몰입감, 현실감, 멀미경감 효과에 영향을 미치므로 3D 가상환경의 몰입감과 현실감을 저하시키지 않고 멀미감을 최소화하는 최적화된 정지좌표계의 형태와 구현변수를 찾는 것은 중요하다. 본 실험에서는 시각적으로 사이버멀미를 유발하는 3D 가상환경을 개발하고 이에 사각터널 형태의 3D 정지좌표계를 개발하였다. 이 효과를 검증하기 위해 10명의 피험자는 rest frame 조건과 non-rest frame 조건에서 각각 3일 간격으로 3D 가상환경을 경험하였으며, 가상환경 노출 시 멀미감에 따른 심박률, 피부전도도, 위장전도, 호흡률 등의 생리적 반응를 측정하고 멀미감을 SSQ(simulator sickness questionnaire)와 자기보고를 이용하여 3D rest-frame의 사이버멀미 경감효과를 검증하였다. 실험결과 정지좌표계의 사용에 따른 SSQ 지수의 유의미한 차이가 발견되지 않았으며, 4가지 생리적 반응 변화에서도 모두 두 조건간의 유의미한 차이가 없었다. 이 결과는 본 연구에서 사용된 3D-사각터널형 정지좌표계가 real 3D 가상환경에서 유발되는 위장전위멀미 감소를 위한 정지좌표계로 적합하지 않다는 것을 잠정 시사한다. Several studies indicated that a rest frame reduced cybersickness, especially the vection induced sickness, associated with exposure to real 3D virtual environments. The form and the way realizing the rest frame in 3D virtual environments have different effects on immersion, presence and reducing cybersickness. Therefore it is important to find the most effective form and method realizing a rest frame in 3D virtual environments reducing cybersickness while at the same time maintaining presence and immersion. In this study, we realized a 3D rectangular-tunnel rest frame and a real 3D virtual environment inducing cybersickness. For verifying the rest frame's effect of reducing cybersickness, 10 subjects were exposed to both rest and non-rest conditions after an interval of three days after the real 3D virtual environment. We recorded electrogastrogram, skin conductance, heart rate, and respiration during the exposure to 3D virtual environment. SSQ (simulator sickness questionnaire) was used for measuring the intensity of the sickness before and after the exposure. The results showed that the scores of SSQ were not reduced significantly by using the rest frame. All 4 electro-physiological responses were not changed significantly from the baseline period to the exposure of 3D virtual environment in the rest frame condition compared to the non-rest frame condition. The results suggest that 3D rectangular-tunnel rest frame is not an adapted rest frame for reducing cybersickness in real 3D virtual environments.