• Title, Summary, Keyword: Refractive index

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Gradient refractive index ITO for high contrast OLEDs

  • Zhu, Furong
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.280-281
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    • 2009
  • Improving the visual contrast in OLED displays is another important issue to address with a significant technological implication. The use of a gradient refractive index anode shows promise for contrast improvements in OLEDs. This talk will discuss the progress in developing gradient refractive index TCO anode for application in high contrast OLEDs.

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Variation of the Representation Ellipsoid for Refractive Index of Bi12GeO20Single Crystal by an Electric Field (전기장에 의한 Bi12GeO20 단결정의 굴절률 표시타원체의 변형)

  • Lee, Su-Dae;Lee, Chan-Ku
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.1
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    • pp.89-95
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    • 2005
  • We derived a formula which can calculate the space distribution of refractive index variation by an applied electric field about Bi$_{12}$ GeO$_{20}$ single crystal. Stereographic projection maps of refractive index variation by an applied electric field were made out using numerical value to be calculated by this formula. By the calculated results, since an electric field had applied to [(equation omitted) 1 1] direction and [1 (equation omitted) 1] direction of Bi$_{12}$ GeO$_{20}$ crystal, positive variation of the refractive index of [(equation omitted) 1 1] direction and [1 (equation omitted) 1] direction was the largest. The incremented refractive index per unit electric field was +3.2410${\times}$10$^{-11}$ V$^{-1}$ for the wavelength of 6328 $\AA$. Since an electric field had applied to [1 1 1] direction and [(equation omitted) 1] direction, negative variation of the refractive index of [1 1 1] direction and [(equation omitted) 1] direction was the largest. The decremented refractive index per unit electric field was -3.2410${\times}$10$^{-11}$ V$^{-1}$ for the wavelength of 6328 $\AA$.

Assessing the Refractive Index of Glass Beads for Use in Road-marking Applications via Retroreflectance Measurement

  • Shin, Sang Yeol;Lee, Ji In;Chung, Woon Jin;Cho, Sung-Hoon;Choi, Yong Gyu
    • Current Optics and Photonics
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    • v.3 no.5
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    • pp.415-422
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    • 2019
  • Retroreflection of vehicle headlights, as induced by spherical glass beads, is a key optical phenomenon that provides road-surface markings with greatly enhanced visibility, thus better securing a driver's safety in the nighttime as well as in unclear daytime. Retroreflectance of glass beads is a quite sensitive function of their refractive index, so that measurement of the refractive index of glass specifically in the shape of spherical beads needs to be performed within a reasonable uncertainty that is tolerable for road-marking applications. The Becke line method has been applied in assessing refractive index of such glass beads as e.g. an industrial standard in the Republic of Korea; however, the reference refractive-index liquids are not commercially available these days for refractive index greater than 1.80 due to the toxicity of the constituent materials. As such, high-refractive-index glass beads require an alternate method, and in this regard we propose a practically serviceable technique with uncertainty tantamount to that of the Becke line method: Based on comparison of calculated and measured retroreflectance values of commercial glass beads, we discover that their refractive index can be determined with reasonable precision via the retroreflectance measurement. Specifically, in this study the normalized retroreflectance originating from a single glass sphere is computed as a function of refractive index using the Fresnel equations, which is then validated as coinciding well with retroreflectance values measured from actual specimens, i.e. glass-bead aggregates. The uncertainties involved are delineated in connection with radius and imperfections of the glass beads.

Correlations between Refractive Index and Retroreflectance of Glass Beads for Use in Road-marking Applications under Wet Conditions

  • Shin, Sang Yeol;Lee, Ji In;Chung, Woon Jin;Choi, Yong Gyu
    • Current Optics and Photonics
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    • v.3 no.5
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    • pp.423-428
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    • 2019
  • Visibility of road-surface markings is one of the critical issues that should be secured for self-driving cars as well as human drivers. Glass beads are taking on the role of retroreflectors, and therefore are considered a necessity in modern pavements. In this context, retroreflectance is sensitively dependent not only on the refractive index of glass beads but also on that of the surrounding medium. This implies that the optimum refractive index of glass beads immersed in water, i.e. under wet conditions, is different from that of glass beads surrounded by air, i.e. under dry conditions. A refractive index of approximately 1.9, which is known to maximize retroreflectance under dry conditions, actually exhibits much poorer retroreflectance under wet conditions. This suggests that glass beads with optimal refractive index for wet conditions need to be installed together with those for dry conditions. We propose a facile but practical model capable of calculating retroreflectance of glass beads surrounded by an arbitrary medium, here water in particular, and experimentally verify its capability of assessing the refractive index of commercial glass beads. Changes in retroreflectance according to the mixing ratio of glass beads with different refractive indices are also discussed, in an effort to propose the proper use of glass beads produced for dry and wet conditions.

Refractive Index Characteristics of Optical Fiber (광섬유의 굴절을 특성)

  • Yuk, Jae-Ho
    • 전자공학회논문지 IE
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    • v.46 no.2
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    • pp.18-21
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    • 2009
  • The optical fiber refractive index sensors were fabricated using etching method and their refractive index characteristics have been investigated. Good sensitivity was shown at the region of 1.452-1.46 refractive index and operating point was shifted by wavelength. The sensitivity of sensor increased with decreasing cladding thickness and was stable with heat treatment. The hysteresis under cyclic refractive index changes was negligible.

Analysis and Measurement of Effective Refractive Indices with Ion-exchanged Slab Waveguide (이온교환 평판도파로의 실효굴절율 측정 및 해석)

  • 천석표;박정일;박태성;정홍배
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.73-76
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    • 1995
  • In this study, the slab waveguide was fabricated using potassium-nitride(KNO$_3$) or silver-nitride (AgNO$_3$) molten sources by ion-exchange process. The effective refractive indices of waveguide were measured by Prism-Coupling method. and The characteristics of waveguide(mode dispersion, effective diffusion depth. surface refractive index, diffusion coefficient, and refractive index profile etc,) were investigated by WKB method, In the case of potassium ion-exchange, the computer calculation showed that the refractive index profile of waveguide followed Gaussian function, the surface refractive index increased with ion-exchange time and the effective diffusion depth increased a little as ion-exchange time increased, while the surface refractive index of silver ion-exchanged waveguide decreased with ion-exchange time because of the ion depletion on the surface of waveguide, and the effective diffusion depth seriously with ion-exchange tim. Double ion-exchanged waveguide was fabricated by performing silver ion-exchange after potassium ion-exchange. Double ion-exchanged waveguide had a tight mode binding force since the surface refractive index was larger than single step ion-exchanged waveguide.

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Ferroelastic Domain and Refractive Property of $Gd_{2}(MoO_{4})_{3}$ Single Crystal ($Gd_{2}(MoO_{4})_{3}$ 단결정의 강탄성구역과 굴절률특성)

  • Son, Jong-Yoon;Lee, Chan-Ku;Lee, Su-Dae;Kim, Jae-Hyung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.98-102
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    • 2002
  • We investigated domains and conoscope under the polarizing microscope and the index of refraction on the c-plate GMO which has the ferroelectric and ferroelastic phase at room temperature. To observed the change of refractive index in connection with domain, we developed an apparatus to obtain the refractive index by measuring the Brewster's angle. The resolution of the minimum rotation angle of this apparatus is $0.001^{\circ}$. To obtain the refractive index map on the sample, the moving distance of XY stage loaded sample holder is 60 mm and the minimum moving distance is 0.002 mm. Also, To obtain the indicatrix for single crystal, vertical turntable with sample holder and XY stage was loading on horizontal turntable. The minimum resolution angle of this vertical turntable is $0.001^{\circ}$. We measured the refractive index of transparent materials such as ferroelectrics. In the case of $Gd_{2}(MoO_{4})_{3}$, the Brewster angle is $62.11^{\circ}$ and then, the refractive index is 1.8895 by using He-Ne Laser. Also the refractive distribution of c-plate GMO was obtained with $400{\mu}m{\times}120{\mu}m$.

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U-Shaped의 POF probe를 이용한 굴절률 변화 측정 Refractive Index Monitoring Using U-shaped POF probe

  • Kim, Seung-Pil;Kim, Gi-Su;Kim, Dong-Min
    • Proceedings of the Optical Society of Korea Conference
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    • pp.291-292
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    • 2009
  • Refractive index monitoring using U-shaped POF (Plastic optical fiber) in the sugar solution and salt solution were performed. The various bending losses of U-shaped POF due to the environmental refractive index changes of the measurand solution. The loss increases according to the amounts of solute in the solution which causes the refractive index change in the solution.

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Three-dimensional Information and Refractive Index Measurement Using a Dual-wavelength Digital Holographic

  • Shin, Sang-Hoon;Yu, Young-Hun
    • Journal of the Optical Society of Korea
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    • v.13 no.2
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    • pp.173-177
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    • 2009
  • Digital holographic microscopy allows optical path difference measurement. Optical path difference depends on the both refractive index and morphology of sample. We developed a dual-wavelength in-line digital holographic microscope that can measure simultaneously the refractive index and morphology of a sample, providing highly precise three-dimensional information. Here we propose theoretical and experimental methods for dual-wavelength in-line digital holographic microscopy. The measured data were reasonable, although there was data error. By improving the experimental method, we could measure the refractive index more precisely and obtain more accurate three-dimensional information on samples.

Optical and dielectric properties dependent on glass composition for photolithographic process of barrier ribs in PDP

  • Won, Ju-Yeon;Kim, Jong-Woo;Hwang, Seong-Jin;Kim, Nam-Suk;Kim, Hyung-Sun
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.878-881
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    • 2007
  • Refractive index of glasses is important to develop a photosensitive paste for barrier rips in PDP. We investigated the refractive index and dielectric constant of glasses by contents of silica in $B_2O_3-Al_2O_3-SiO_2$ glasses. It is confirmed that the refractive index of the glass system is changed by the composition of glasses

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