• Journal of Electrical Engineering and Technology
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• v.8 no.1
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• pp.163-167
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• 2013

Aluminum doped zinc oxide (AZO) thin films have been prepared on the glass substrates (Corning 1737) by sol-gel dip-coating method employing zinc acetate and aluminum chloride hexahydrate for the transparent conducting oxide (TCO) applications. 1 at% Al was doped to the ZnO thin films. The effects of post-heating temperature on the crystallization, optical and electrical properties of the AZO films have been investigated. Experimental results showed that post-heating temperature affected the microstructure, electrical resistance, and optical transmittance of the AZO films. From the X-ray diffraction analysis, all films have hexagonal wurtzite crystal structure. Optical transmittance spectra of the AZO films exhibited transmittance higher than about 80% within the visible wavelength region and the optical direct band gap ($E_g$) of these films was increased with increasing post-heating temperature. A minimum resistivity of $2.5{\times}10^{-3}{\Omega}cm$ was observed at $650^{\circ}C$.

• Transactions of the Society of Information Storage Systems
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• v.2 no.3
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• pp.178-183
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• 2006

A Blu-ray disc, which has a more than 25GB optical capacity, has been known as a promising next-generation optical disc format. It commonly has a 1.1 mm thick substrate and a 0.1 mm thick cover layer for beam transmitting and the protection of the reflecting surface. The cover layer is generally formed by the spin coating process. However, in conventional spin coating, small bumps are formed along the rim of the disc, which results in the fatal reading error. Numerical simulation of the thin film flow behaviors during spin coating with the commercial solver and optimal spinning conditions was obtained. Thickness distribution of the cover layer according to the variation of substrate's edge shape could be calculated as well. By modifying the shape of the substrate edge shape, the bumps along the disc rim could be minimized, and it was proved that the chamfered edge, around $5{\sim}10$ degree, is the simplest and most effective way to minimize the bumps.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.11
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• pp.991-994
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• 2007

In this paper, we have designed the anti-reflection(AR) coating for $1400{\sim}1600$ nm wavelength range on the ferrule facet of optical connector. The low-temperature ion-assisted deposition was applied to AR coating on the ferrule facet in order to avoid damage of optical connector. We have measured the refractive index of coating film($Ta_2O_5\;and\;SiO_2$) using the ellipsometer and optimized the film thickness using the SEM and thickness measurement equipment. UV-VIS-NIR spectrophotometer is used to measure transmissivity of the AR coated ferrule facet. The refractive index of $Ta_2O_5\;and\;SiO_2$ is $2.123{\sim}2.125$ and $1.44{\sim}1.442$, respectively, for $1400{\sim}1600$ nm wavelength range. The transmissivity of the AR coated ferule facet is more than 99.8 % for $1425{\sim}1575$ nm wavelength range and more than 99.5 % for $1400{\sim}1600$ nm wavelength range. The return loss of the AR coated ferrule facet is 30.1 dB.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.31-43
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• 1997

In this paper, the rate of transmittance regarding the home -and foreign-made lens that have been treated with multi coating and no coating has been studied in the range of the visible ray. The lens that were treated with No Coating turned out to be about 93% of the rate of transmittance, but those treated with Coating turned out to be over 98%. Especially, the rate of transmittance of product made by a company in a foreign country turned out to be homogeneous in the whole range.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.58-65
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• 2022

The field of liquid crystal display (LCD) is constantly in the spotlight and the process of depositing an alignment layer in the LCD manufacturing process is very important to obtain excellent performance such as low-power driving and high-speed response to improve LCD performance. Therefore, research on liquid crystal (LC) alignment is being actively conducted. When manufacturing LCD, it is necessary to consider the effect of the alignment layer thickness as one of the factors affecting various LCD performances. In addition, previous studies confirmed the LC alignment characteristics correlate with the rotation speed in the spin coating process. Therefore, the electro-optical properties of the LCD were investigated by manufacturing a polyimide alignment layer by varying the rotation speed in the spin coating process in this study. It was confirmed that the thickness of the polyimide alignment layer was controlled according to the spin coating conditions. The average transmittances of anti-parallel LC cells at the spin coating speed of 2,500 rpm and 3,000 rpm are about 60%, which indicates that the LC cell has relatively higher performance. At the spin coating speed of 3,000 rpm, the voltage-transmittance curve of twisted nematic (TN) LC cell was below 1.5 V, which means that the TN LC cell operated at a low power. In addition, high-speed operating characteristics were confirmed with a response time of less than 30 ms. From these derived data, we confirmed that the ideal spin coating speed is 3,000 rpm. And these results provide an optimized polyimide alignment layer process when considering enhanced future LCD manufacturing.

• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.184-185
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• 2005

• Transactions of the Society of Information Storage Systems
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• v.6 no.2
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• pp.68-73
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• 2010

The interest in acquiring high efficiency solar cells has been steadily increasing due to various advantages such as low-cost installation, pollution free and everlasting energy generation. In order to raise the cell efficiency, there has been a lot of effort to develop effective anti-reflection coatings. In this work, the main objective was to investigate the effects of particle size and annealing temperature of silica anti-reflection coatings to maximize the cell efficiency as well as reliability. It was shown that the light transmittance could be increased by a few percent over a certain range of wavelength using the silica coating. Also, the tribological properties of the coating could be improved through the annealing process, which led to better reliability of the coating.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.15-18
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• 2012

Transparent conductive indium zinc oxide thin films were prepared by spin-coating a sol-gel solution. Zinc acetate dihydrate [$Zn(CH_3COO)_2{\cdot}2H_2O$] and indium acetate [In$(CH_3COO)_3$] were used as starting precursors, and 2-methoxyethanol with 1-propanol as solvents. Upon annealing in a temperature range from 500 to $1000^{\circ}C$, the thin film crystallizes into polycrystalline $In_2O_3$(ZnO). The lowest electrical resistivity was obtained at an annealing temperature of $700^{\circ}C$ as $2{\Omega}{\cdot}cm$. Average optical transmittances were higher than 80% at all annealing temperatures. These experimental results confirm that the sol-gel spin-coating can be a good simplified practical method for forming transparent electrodes.

• Current Optics and Photonics
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• v.1 no.4
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• pp.284-288
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• 2017

In order to investigate the ultraviolet-excited photoluminescence properties of phosphor coatings and their relationship to thickness, Lumogen coatings with different thicknesses were deposited on quartz substrates and charge-coupled device chips by thermal evaporation. The variation of the film thickness affected the crystallite size, surface roughness and fluorescence signal. It was found that the Lumogen coating with the thickness of 420 nm has the largest luminescent signal and conversion efficiency, and the corresponding coated charge-coupled devices had the maximum quantum efficiency in the ultraviolet. These results provided one key parameter for improving the sensitivity of Lumogen coated charge-coupled devices to ultraviolet light.

• The Korean Journal of Ceramics
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• v.2 no.2
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• pp.89-94
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• 1996

Aluminum and zinc titanium silicate sol-gel films were fabricated for application of waveguide and the effect of additions of ZnO and $Al_2O_3$ to binary titanium silicate films was investigated. During firing, the films are densified as they shrunk and their refractive index increases in the range of 1.58-1.83 depending on the film composition. The attenuation of the waveguides is not sensitive to changes in composition except for zinc titanium silicate waveguides which have substantially higher attenuation. However, the increase in the attenuation with aging of the waveguides depend upon the composition of waveuides. The addition $Al_2O_3$ or the reduced $SiO_2$ content in the composition appears to slow the deterioration of the waveguides due to the formation of more stable bonds and increased acidity on the film surface. Also, the wavelength dependence of the attenuation of the waveguides varies with composition. The attenuation of the waveguides except for the $65SiO_2{\cdot}35TiO_2$ composition are not Rayleigh scatter limited, suggesting the absorption loss of the waveguides due to the effects of residual carbon and structural defects in the films.