PURPOSES : The purpose of this study is to verify the effect of improving the retroreflectivity of pavement marking by increasing the refractive index of glass bead. METHODS : Pavement marking test-beds has been installed in National Highway 19, 42 and KICT Yeoncheon SOC Center. In testbeds several marking sections were installed for each type of marking materials and glass beads. In this test-beds initial dry and wet retroreflectivity were measured and analyzed. RESULTS : When the refractive index of glass bead was adjusted upward in water based paint(glass bead No.1→ No.2), dry retroreflectivity increased by about 30 to 70%, and wet retroreflectivity slightly increased by about 10 to 40%. When using glass bead No. 2 in water based paint, it was found to meet the standards of the Road Traffic Act. However, since wet retroreflectivity of water based paint slightly exceeds the standard value, a follow-up investigation is needed to determine how long this performance can be maintained. When using glass bead No.1 in MMA(methyl methacrylate), the average wet retroreflectivity was evaluated to be 128 to 150 mcd/lx/m2, and when using glass bead No.2, the average wet retroreflectivity was evaluated to be about 200 to 270 mcd/lx/m2. Accordingly, MMA showed the best performance compared to other paints. CONCLUSIONS : When using glass bead No.1 in water-soluble paints and thermoplastic, it did not meet the wet retroreflectivity standards of the Road Traffic Act. But when using glass bead No.2, it met the wet retroreflectivity standards. As a result of analyzing the road marking budget according to the upward adjustment of the refractive index of glass bead, it was analyzed that if only the material class was adjusted upward, the cost would increase by more than twice the current budget. In order to decrease this budget increase rate(to increase service life), it is necessary to strengthen quality control standards for pavement marking and develop scientific-systematic quality control techniques.

Zirconia nanoparticles were widely used as filler in order to get high refractive index layer. However, dispersion of nanoparticles is difficult due to their agglomeration in solvent. In this study, the dispersibility of the zirconia suspension is promoted by controlling the steric hindrance and electrostatic interactions through the adsorption of PEI according to alkali treatment time. Also, to induce improved dispersibility on suspension, we changed the dispersion conditions variously and fabricated an ink formulation method for the coating layer. Zirconia suspension was characterized by dynamic light scattering (DLS), Zeta potential measurement, Transmission Electron Microscope (TEM) and FT-IR. We were able to confirm that good dispersion of zirconia suspension by alkali treatment and PEI led to high refractive index.

목 적: 곡률이 없는 안경렌즈 위에 하드 코팅 막과 SiO2 막을 쌓은 후, FDTD를 사용하여 원기둥 hole 나노 구조물을 설계하고, 나노 구조 형태에 따른 안경렌즈 코팅막의 굴절률을 연구하였다. 방 법: 시뮬레이터 설계에서 안경렌즈 위에 하드코팅 막을 1.5 μm로 하고, 그 위에 SiO2 막을 100 nm에 서 900 nm까지 변화시켰으며, SiO2 막에 원기둥 hole 모양의 나노 구조를 만들고 원기둥 hole의 배열을 hexagonal로 하였다. 원기둥 hole 깊이와 주기를 고정하고 hole 반경을 변화시켜 반사율이 최소가 되는 파장위치를 찾아 나노 SiO2 막의 굴절률을 계산하였다. 그리고 원기둥 hole 반경과 주기를 고정하고 깊이를 변화시켜 깊이에 따른 반사스펙트럼을 관찰했으며, 또한 원기둥 hole 깊이를 고정시키고 반경과 주기를 변화시켜 주기에 따른 반사스펙트럼을 관찰했다. 또한 원기둥 hole의 반사율 스펙트럼을 좀 더 자세히 분석하기 위해서 원기둥 hole의 배열을 square로 했을 때 반사율 스펙트럼도 관찰하였다. 결 과: 원기둥 hole 깊이를 100 nm로, 주기를 300 nm로 고정하고 반경을 변화시킨 결과, hole 반경이 70 nm일 때 반사율이 영인 파장위치는 508 nm이었다. 이 때, 나노 SiO2 막의 굴절률은 소멸간섭 조건에 의해 계산한 값은 1.27이고, 진폭 조건으로는 1.24로 거의 비슷한 값을 가짐을 알 수 있었다. 그리고 원기둥 hole 높이가 100 nm 이상에서는 간섭현상이 일어나며 높이가 커질수록 반사율이 최대 최소를 이루는 파장의 개수가 점점 많아짐을 알 수 있었다. 또한 시뮬레이션 주기는 100 nm에서 300 nm까지는 반사방지막 효과가 나타나고 400 nm 이상에서는 반사방지막 효과와 회절이 합쳐진 현상이 나타남을 알 수 있었다. 결 론: 반사율이 영일 때 나노 SiO2 막의 굴절률은 소멸 간섭조건에 의해 계산한 값은 1.27이고, 진폭조 건으로는 1.24이다. 또한 시뮬레이션 주기는 100 nm에서 300 nm까지는 반사방지막 효과가 나타나다가 400 nm 이상에서는 반사방지막 효과와 회절이 합쳐진 현상이 나타남을 알 수 있었다.

In fabricating plasma display panels, the photolithographic process is used to form patterns of barrier ribs with high accuracy and high aspect ratio. It is important in the photolithographic process to control the refractive index of the photosensitive paste. The composition of this paste for photolithography is based on the B2O3-SiO2-Al2O3 glass system, including additives of alkali oxides and rare earth oxides. In this work, we investigated the density, structure and refractive index of glasses based on the B2O3-SiO2-Al2O3 system with the addition of Li2O, K2O, Na2O, CaO, SrO, and MgO. The refractive index of the glasses containing K2O, Na2O and CaO was similar to that of the [BO3] fraction while that of the SrO, MgO and Li2O containing glasses were not correlated with the coordination fraction. The coordination number of the boron atoms was measured by MAS NMR. The refractive index increased with a decrease of molar volume due to the increase in the number of non-bridging oxygen atoms and the polarizability. The lowest refractive index (1.485) in this study was that of the B2O3-SiO2-Al2O3-K2O glass system due to the larger ionic radius of K+. Based on our results, it has been determined that the refractive index of the B2O3-SiO2-Al2O3 system should be controlled by the addition of alkali oxides and alkali earth oxides for proper formation of the photosensitive paste.

목적: 전면이 평면인(γ=∞) 하드코팅 된 렌즈에서 코팅박막의 두께와 굴절률을 박막의 손상없이 측정한다. 방법: He-Ne 레이저를 박막에서 도파되도록 렌즈로 집속시켜 Gadoliniun Gallium Garnet(G.G.G.) 프리즘에 입사시키고 입사된 광의 고유모드 중 일부가 도파관을 새어나가서 m차 line(m은 정수)으로 관측되도록 장치하였다. 이 line들 사이의 떨어진 거리를 광 검출기로 측정하는 prism-film coupler 방법으로 실험하였다. 결과: TE(transverse electric) mode에서 박막두께는 약 2.42 ㎛, TM(transverse magnetic) mode에서는 약 2.55 ㎛로 평균 약 2.49 ㎛로 측정되었고, 굴절률은 두 mode에서 약 1.60으로 같은 값을 얻었다. 결론: 이 값(2.49 ㎛)은 전자현미경(SEM)으로 측정한 두께와는 5.5%의 오차를 나타냈다.