In this study, two alignment methods were used to create a Fringe-Field Switching (FFS) mode liquid crystal device using an organic thin film (polyimide: PI) as an alignment layer. In addition, the electro-optical (EO) characteristics of the liquid crystal device manufactured in this way were investigated to evaluate the feasibility of mass production application of the technology. In general, the photo-alignment method using unpolarized ultraviolet rays can obtain a relatively low pretilt angle, so a liquid crystal device in FFS mode, which is a driving mode of the liquid crystal device that reflects the characteristics of liquid crystal alignment, was manufactured, and the liquid crystal has a high reactivity with the alignment film. Considering this, nematic liquid crystal (NLC) was used. In addition, in order to improve the misalignment, it was observed whether more stable orientation occurred by irradiating ultraviolet rays for an additional 1 to 3 hours in the aligned state. As a result of the experiment, it was found that NLC alignment occurs through a photodecomposition reaction caused by unpolarized UV irradiation oblique to the PI surface. In addition to the existing orientation method, UV irradiation was used to achieve a more stable orientation state and stable V-T curve and response characteristics. With liquid crystal alignment completed, more stable orientation characteristics and EO characteristics at the mass production level were obtained through additional UV irradiation for 3 hours. This method can further stabilize the orientation stability caused by existing UV irradiation through an additional process.

Fluorine-doped tin oxide (FTO) has been used as a representative transparent conductive oxide (TCO) in various optoelectronic applications, including light emitting diodes, solar cells, photo-detectors, and electrochromic devices. The FTO plays an important role in providing electron transfer between active layers and external circuits while maintaining high transmittance in the devices. Herein, we report the effects of substrate rotation speed on the electrical and optical properties of FTO films during ultrasonic spray pyrolysis deposition (USPD). The substrate rotation speeds were adjusted to 2, 6, 10, and 14 rpm. As the substrate rotation speed increased from 2 to 14 rpm, the FTO films exhibited different film morphologies, including crystallite size, surface roughness, crystal texture, and film thickness. This FTO film engineering can be attributed to the variable nucleation and growth behaviors of FTO crystallites according to substrate rotation speeds during USPD. Among the FTO films with different substrate rotation speeds, the FTO film fabricated at 6 rpm showed the best optimized TCO characteristics when considering both electrical (sheet resistance of 13.73 Ω/□) and optical (average transmittance of 86.76 % at 400~700 nm) properties with a figure of merit (0.018 Ω-1).

ZnO/Cu/ZnO (ZCZ) thin films were deposited at room temperature on a glass substrate using direct current (DC) and radio frequency (RF, 13.56 MHz) magnetron sputtering and then the effect of post-deposition electron irradiation on the structural, optical, electrical and transparent heater properties of the films were considered. ZCZ films that were electron beam irradiated at 500 eV showed an increase in the grain sizes of their ZnO(102) and (201) planes to 15.17 nm and 11.51 nm, respectively, from grain sizes of 13.50 nm and 10.60 nm observed in the as deposited films. In addition, the film’s optical and electrical properties also depended on the electron irradiation energies. The highest opto-electrical performance was observed in films electron irradiated at 500 eV. In a heat radiation test, when a bias voltage of 18 V was applied to the film that had been electron irradiated at 500 eV, its steady state temperature was about 90.5 °C. In a repetition test, it reached the steady state temperature within 60 s at all bias voltages.

Transparent conductive tungsten (W) doped indium oxide (In2O3; IWO) films were deposited at different substrate bias voltage (-Vb) conditions at room temperature on glass substrates by radio frequency (RF) magnetron sputtering and the influence of the substrate bias voltage on the optical and electrical properties was investigated. As the substrate bias voltage increased to -350 Vb, the IWO films showed a lower resistivity of 2.06 × 10-4 Ωcm. The lowest resistivity observed for the film deposited at -350 Vb could be attributed to its higher mobility, of 31.8 cm2/Vs compared with that (6.2 cm2/Vs) of the films deposited without a substrate bias voltage (0 Vb). The highest visible transmittance of 84.1 % was also observed for the films deposited at the -350 Vb condition. The X-ray diffraction observation indicated the IWO films deposited without substrate bias voltage were amorphous phase without any diffraction peaks, while the films deposited with bias voltage were polycrystalline with a low In2O3 (222) diffraction peak and relatively high intensity (431) and (046) diffraction peaks. From the observed visible transmittance and electrical properties, it is concluded that the opto-electrical performance of the polycrystalline IWO film deposited by RF magnetron sputtering can be enhanced with effective substrate bias voltage conditions.

AZO/Cu/AZO thin films were deposited on glass by RF magnetron sputtering. The specimens showed the preferred orientation of (0002) AZO and (111) Cu. The Cu crystal sizes increased from about 3.7 nm to about 8.5 nm with increasing Cu thickness, and from about 6.3 nm to about 9.5 nm with increasing heat treatment temperatures. The sizes of AZO crystals were almost independent of the Cu thickness, and increased slightly with heat treatment temperature. The residual stress of AZO after heat treatment also increased compressively from -4.6 GPa to -5.6 GPa with increasing heat treatment temperature. The increase in crystal size resulted from grain growth, and the increase in stress resulted from the decrease in defects that accompanied grain growth, and the thermal stress during cooling from heat treatment temperature to room temperature. From the PL spectra, the decrease in defects during heat treatment resulted in the increased intensity. The electrical resistivities of the 4 nm Cu film were 5.9 × 10-4 Ω ‧ cm and about 1.0 × 10-4 Ω ‧ cm for thicker Cu films. The resistivity decreased as the temperature of heat treatment increased. As the Cu thickness increased, an increase in carrier concentration resulted, as the fraction of AZO/Cu/AZO metal film increased. And the increase in carrier concentration with increasing heat treatment temperature might result from the diffusion of Cu ions into AZO. Transmittance decreased with increasing Cu thicknesses, and reached a maximum near the 500 nm wavelength after being heat treated at 200 °C.

목적 : SMILE 수술 후 발생하는 광학적 현상을 이론적으로 분석하고, 렌티큘 절삭량에 따른 교정시력의 변화 를 분석하였다. 방법 : SMILE 수술에서 절삭량에 따른 초점거리 및 수차의 변화를 Listing의 생략안을 기반으로 광선추적을 사용하여 이론적으로 분석하였다. 결과 : 수술부위 절삭량이 증가할수록 교정시력은 향상되었다. 교정시력이 향상될수록 수술부위와 수술부위 외 부의 곡률차이가 증가하게 되며 이로 인하여 구면수차가 증가하게 된다. 결론 : 근시가 증가할수록 수술 부위와 외부 곡률의 차이로 인하여 구면수차가 증가한다. 수술 후 수차의 증가 는 수차 분석 결과에 의해 수술 중 발생하는 광학적 현상임을 확인하였다. 수술 후 나타나는 다양한 증상과 후광 및 눈부심의 원인을 이론적으로 분석하기 위해서는 다양한 수술 사례를 활용한 후속 연구가 필요하다고 판단된다.

산업이 발달함에 따라 이산화탄소, 휘발성 유기 화합물, 일산화탄소 등과 같은 독성 가스의 감지 및 모니터링이 중요시되고 있다. 새롭게 합성된 0 차원의 비납계 무기 페로브스카이트 소재는 광학적 방법과 전기적 방법을 융합하여 사용할 수 있는 가스 센서 특성을 가진다. 친환경 가스 센서는 결정의 상변이를 기반으로, 광학 및 전기적 특성 변화를 가져 하이드록실기 감지가 가능하며, 하이드록실기 극성과의 상관관계를 통해 차세대 센서 소자로의 응용 가능성이 기대된다.

목적 : 3D 시뮬레이션을 통해 구현된 Gullstrand 모형안에서 눈의 광학적 특성을 분석하였다. 방법 : 시뮬레이션 프로그램인 SPEOS를 이용하여 Gullstrand 모형안을 모델링하였다. 결과 : 모델링된 모형안으로 입사된 평행광선은 모두 망막 앞에 결상하는 것으로 나타났으며, 이는 근사 없이 계산한 결과 및 일반적으로 잘 알려진 결과와 일치하였다. 평행광선의 입사 높이에 따른 초점심도를 분석한 결과 입사 높이에 따라 지수 함수 형태로 급격히 감소하였다. 또한 구면수차는 입사광선의 높이에 따라 비선형적으로 증가하였다. 결론 : 본 연구와 같이 생체적으로 접근이 어려운 눈의 광학적 현상은 시뮬레이션에 따른 결과 분석을 통해 이 해도를 좀 더 높일 수 있고, 눈의 다양한 광학적 현상에 적용될 수 있을 것으로 판단된다.

Zinc oxide (ZnO) based transparent conducting oxides (TCO) thin films, are used in many applications such as solar cells, flat panel displays, and LEDs due to their wide bandgap nature and excellent electrical properties. In the present work, fluorine and aluminium-doped ZnO targets are prepared and thin films are deposited on soda-lime glass substrate using a RF magnetron sputtering unit. The aluminium concentration is fixed at 2 wt%, and the fluorine concentration is adjusted between 0 to 2.0 wt% with five different concentrations, namely, Al2ZnO98(AZO), F0.5AZO97.5(FAZO1), F1AZO97(FAZO2), F1.5AZO96.5(FAZO3), and F2AZO96(FAZO4). Thin films are deposited with an RF power of 40 W and working pressure of 5 m Torr at 270 oC. The morphological analysis performed for the thin film reveals that surface roughness decreases in FAZO1 and FAZO2 samples when doped with a small amount of fluorine. Further, optical and electrical properties measured for FAZO1 sample show average optical transmissions of over 89 % in the visible region and 82.5 % in the infrared region, followed by low resistivity and sheet resistance of 3.59 × 10−4 Ωcm and 5.52 Ω/sq, respectively. In future, these thin films with excellent optoelectronic properties can be used for thin-film solar cell and other optoelectronics applications.

AZO thin films are grown on a p-Si(111) substrate by RF magnetron sputtering. The characteristics of various thicknesses and heat treatment conditions are investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Hall effect and room-temperature photoluminescence (PL) measurements. The substrate temperature and the RF power during growth are kept constant at 400 ℃ and 200 W, respectively. AZO films are grown with a preferred orientation along the c-axis. As the thickness and the heat treatment temperature increases, the length of the c-axis decreases as Al3+ ions of relatively small ion radius are substituted for Zn2+ ions. At room temperature, the PL spectrum is separated into an NBE emission peak around 3.2 eV and a violet regions peak around 2.95 eV with increasing thickness, and the PL emission peak of 300 nm is red-shifted with increasing annealing temperature. In the XPS measurement, the peak intensity of Al2p and Oll increases with increasing annealing temperature. The AZO thin film of 100 nm thickness shows values of 6.5 × 1019 cm−3 of carrier concentration, 8.4 cm−2/V·s of mobility and 1.2 × 10−2 Ω·cm electrical resistivity. As the thickness of the thin film increases, the carrier concentration and the mobility increase, resulting in the decrease of resistivity. With the carrier concentration, mobility decreases when the heat treatment temperature increases more than 500 ℃.

The effects of fast neutron irradiation on the electrical and optical properties of Li (3 at%) doped ZnSnO (ZTO) thin films fabricated using a sol-gel process are investigated. From the results of Li-ZTO TFT characteristics according to change of neutron irradiation time, the saturation mobility is found to increase and threshold voltage values shift to a negative direction from 1,000 s neutron irradiation time. X-ray photoelectron spectroscopy analysis of the O 1s core level shows that the relative area of oxygen vacancies is almost unchanged with different irradiation times. From the results of band alignment, it is confirmed that, due to the increase of electron carrier concentration, the Fermi level (EF) of the sample irradiated for 1,000 s is located at the position closest to the conduction band minimum. The increase in electron concentration is considered by looking at the shallow band edge state under the conduction band edge formed by fast neutron irradiation of more than 1,000 s.

목적 : 근적외선 흡수렌즈의 광학적 특성과 단열특성을 분석하였다. 방법 : 선명도를 분석하기 위해 화상테스트 차트를 카메라로 촬영하였고, 이미지 분석 프로그램을 이용하여 분석하였다. 32명을 대상으로 시력을 측정하였다. 단열효과를 분석하기 위해 돼지피부와 안검 피부에 근적외선을 조사하고 디지털온도계와 열화상카메라를 사용하여 온도를 측정했다. 렌즈 표면에 근적외선을 조사하여 표면온도를 측정하였고, 열에 의한 렌즈손상을 관찰하였다. 근적외선 흡수안경과 착색안경을 착용하고 선명도, 눈부심, 열감, 광량에 대한 주관적 만족도를 평가하였다. 결과 : 근적외선 흡수렌즈와 착색렌즈에 의한 선명도와 시력은 유의한 차이가 없었다. 근적외선 흡수렌즈를 착용 했을 때 돼지피부와 사람 안검의 온도변화는 착색렌즈를 착용했을 때보다 더 낮았다. 근적외선 조사에 의해 근적외선 흡수렌즈가 착색렌즈보다 표면의 온도가 더 높았고, 더 빨리 손상되었다. 설문조사에서 근적외선 흡수렌즈에 의한 선명도(p=0.040)와 눈부심(p=0.000)에 관한 만족도는 모두 청색렌즈보다 더 높았지만 나머지 착색렌즈들과 유의한 차이가 없었다. 근적외선 흡수렌즈에 의한 열감과 광량에 관한 주관적 만족도는 착색렌즈보다 더 높았다. 결론 : 근적외선 흡수렌즈와 착색렌즈에 의한 선명도와 시력은 유의한 차이가 없었으며, 근적외선 흡수렌즈의 단열효과는 착색렌즈보다 더 좋았다. 본 연구는 근적외선 흡수렌즈의 단열효과에 대한 기초자료를 제시하였다고 생각된다.

목적 : 각막에서 일어나는 광학적 현상을 분석하기 위하여, 콜라겐과 동일한 광 특성을 갖는 나노물질에 대한 산란, 회절, 간섭에 의한 광 특성을 조사하였다. 방법 : 광 특성 분석 시뮬레이션 소프트웨어를 이용하여 콜라겐섬유와 동일한 물질의 광 특성을 분석하였다. 입사 빛이 콜라겐섬유를 통과할 때 전기장의 세기 분포를 확인하여 산란 현상을 분석하였다. 또한 콜라겐 광 특성을 갖는 슬릿에서의 광세기 분포를 확인하여, 일반적인 회절 및 간섭 현상과 비교하여 분석하고자 하였다. 결과 : 300~900 nm의 파장 분포를 갖는 입사 빛이 콜라겐섬유의 전·후 검출기에서 파장 별 투과율에 변화가 있는 것을 확인하였다. 특히 589 nm에서는 콜라겐 섬유를 통과한 후 광세기가 통과 이전보다 미세하게 높아졌다. 콜라겐 광 특성을 갖는 판에 빛을 입사시키면 입사 빛과 반사 빛이 중첩되어 정상파를 형성하였다. 정상파의 중심 파장은 589 nm이고 배와 마루는 대략 312 nm 간격으로 반복되었다. 단일 슬릿과 이중 슬릿에 빛을 입사시킨 경우 에도 동일하게 정상파가 관측되었으며, 슬릿 간격 및 두께에 따른 광 투과율에 변화가 있는 것을 확인하였다. 결론 : 콜라겐은 광학적으로 투명하기 때문에, 콜라겐의 광학적 특성을 갖는 판에 의한 투과광의 세기 분포는 일반적인 불투명 물체의 간섭 및 회절에 의한 광세기 분포와는 같지 않음을 확인하였다. 불투명 물체 및 금속에 의한 광학적 현상의 비교 분석 필요하며 이 결과는 다양한 분야에 적용될 수 있을 것으로 판단된다.

This study investigates the optical characteristics of InGaN multiple quantum wells(MQWs) light emitting diodes(LEDs) on planar sapphire substrates(PSSs), nano-sized PSS(NPSS) and micro-sized PSS(MPSS). We obtain the results as the patterning size of the sapphire substrates approach the nanometer scale: The light from the back side of the device increases and the total light extraction becomes larger than the MPSS- and planar-LEDs. The experiment is conducted by Monte Carlo ray-tracing, which is regarded as one of the most suitable ways to simulate light propagation in LEDs. The results show fine consistency between simulation and measurement of the samples with different sized patterned substrates. Notably, light from the back side becomes larger in the NPSS LEDs. We strongly propose that the increase in the light intensity of NPSS LEDs is due to an abnormal optical distribution, which indicates an increase of extraction probability through NPSS.

Three new asymmetric light emitting organic compounds were synthesized with diphenylamine or triphenylamine side groups; 10-(3,5-diphenylphenyl)-N,N-diphenylanthracen-9-amine (MADa), 4-(10-(3,5-diphenylphenyl)anthracen-9-yl)-N,N-diphenylaniline (MATa), and 4-(10-(30,50-diphenylbiphenyl-4-yl) anthracen-9-yl)-N,N-diphenylaniline (TATa). MATa and TATa had a PLmax at 463 nm in the blue region, and MADa had a PLmax at 498 nm. The EL efficiency and color coordinate values (respectively) were 10.3 cd/A and (0.199, 0.152; bluish-green) for the MADa device, 4.67 cd/A and (0.151, 0.177) for the MATa device, and 6.07 cd/A and (0.149, 0.177) for the TATa device. The TATa device had a high external quantum efficiency (EQE) of 6.19%, and its luminance and power efficiencies and life-time were more than twice those of the MADN device.

We synthesized new hole-transporting material, N,N'-diethyl-3,3'-bicarbazyl (E-Cvz-2), 9,9'-diethyl-6-(9-ethyl-carbazol-3-yl)-3,3'-bicarbazole (E-Cvz-3), 6-(9,9'-diethyl-3,3'-bicarbazol-6-yl)-9,9'-diethyl-3,3'-bicarbazole (E-Cvz-4A) and 9-ethyl-6-(9-ethyl-3,9'-bicarbazol-6-yl)-3,9'-bicarbazole (E-Cvz-4B). EL luminance efficiencies of E-Cvz-2, E-Cvz-3, E-Cvz-4A and E-Cvz-4B devices were found to be 4.77, 5.68, 4.27 and 4.64 cd/A, respectively, when synthesized materials are using as a HTL material. The luminance efficiency of E-Cvz-3 is 25% higher than that of NPB, a commercialized HTL material used as a reference in this study.