• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.98-103
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• 2008

The glass for crystalline PV module fabrication should have high thermal and mechanical resistance to environmental also have high transparency. In this paper, we analyze the optical characteristics of glasses for photovoltaic module application. The transmittance of several glasses are measured. The effects of texturing on low iron glass, glass thickness, anti-reflective glass, photocatalyst-treated glass and special glass are compared each other. Then this will give some information to select PV glass for manufacturing. The detailed analysis is described in the following paper.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.165-173
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• 1994

Retroreflector is different from other reflecting surfaces as it mades reflection in which radiation is returned in directions close to its incoming direction. Because of this characteristics, retroreflectors find many applications in traffic safety related areas. Retroreflectors are usually made using comer cubes, or partially coated glass beads. These glass beads can be made very small, so that they can be coated on sheets or mixed with paints. The design of glass type retroreflector depends on glass bead's shape and material, and its optical characteristics are related to the refractive index of glass. In this paper, a method of anlyzing glass bead type retroreflector's sptical characteristics with respect to shape and optica property of the glass, is presented. First, the coefficient of retroreflection, which is a measure of retroreflector's optical characteristics, is derived analytically using geometrical optics method. And the result is plotted using numerical methods. The results show good match with those obtained experimentally, which were supplied from a commercial retroreflector manufacturer.

• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.182-187
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• 2015

This paper presents a new graphical method for selecting a pair of optical glasses to simultaneously achromatize and athermalize an imaging lens made of materials in contact. An athermal glass map that plots thermal glass constant versus inverse Abbe number is derived through analysis of optical glasses and plastic materials in visible light. By introducing the equivalent Abbe number and equivalent thermal glass constant, although it is a multi-lens system, we have a simple way to visually identify possible optical materials. Applying this method to design a phone camera lens equipped with quarter inch image sensor having 8-mega pixels, the thermal defocuses over $-20^{\circ}C$ to $+60^{\circ}C$ are reduced to be much less than the depth of focus of the system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.94-97
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• 2003

A precise fabrication technology of glass is increasingly demanded fer the latest Industrial applications of spherical lenses. micro-optical components, laser applications and so on. Most of cases, the surface roughness of glass is required to be minute for improving the optical characteristics. Then. the machining characteristics of SF-5 glass and quarts glass were studied by using the ELID grinding process to get mirror surface and productivity compared with a general lapping process. A rotary type grinder with ELID generator was used to make the mirror surface of glass and a Mitutoyo surface tester and a nano-hardness tester were also used to measure the grinded surface or glass. As the results of experiments. they showed that the surface roughness(Ra) of SF-5 glass was under 7.8 nm and that of quartz glass was under 3.0 nm using the # 8000 grinder. So, the possibility of highly efficient and accurate surface for optical components can be achieved by the ELID grinding process.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.88-91
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• 2011

Glass fiber drawing from a silica preform is one of the most important processes in optical fiber manufacturing. High purify silica preform of cylindrical shape is fed into the graphite furnace, and then a very thin glass fiber of 125 micron diameter is drawn from the softened and heated preform. A computational analysis is performed to investigate the heat transfer characteristics of preform heating and the glass fiber drawing in the furnace. In addition to the dominant radiative heating of preform by the heating element in the furnace, present analysis also includes the convective heat transport by the gas flowing around the preform that experiences neck-dawn profile and the freshly drawn glass fiber at high fiber drawing speed. The computational results present the effects of gas flow on the temperature of preform and glass fiber as well as the neck-down profile of preform.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.9
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• pp.641-645
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• 2013

Chalcogenide glass has superior property of optical transmittance in the infrared region. Glass made using Ge-Se how many important optical applications. We have determined the composite formular of $Ge_{0.25}Se_{0.75}$ to be the GeSe chalcogenide glass composition appropriate for IR lenses. Also, the optical, thermal and physical characteristics of chalcogenide glass depended on the composition ratio. GeSe bulk sample is produced using the traditional melt-quenching method. The optical, structural, thermal and physical properties of the compound were measured by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Differential scanning calorimeter (DSC), and Scanning electron microscope (SEM) respectively.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.167-172
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• 2002

Recent years, optical components'are widely used in optical communication industry for high speed and mass storage data processing. Micro grooving of planar lightwave circuit and glass, those are widely used in optical component, are realized by polycrystalline diamond tool with ultrasonic vibration. To know the characteristics of brittle materials cutting, ultrasonic vibration cutting tool and machining system are built for the experiment. Grooving on planar lightwave circuit and glass experiments are performed and their shape are measured by photograph with microscope. It reveals that better groove shape with low chipping of planar lightwave circuit and glass are obtained by micro grooving machining with ultrasonic vibration. These experiments are considered as a possibility to the micro grooving of optical communication components.

• Current Optics and Photonics
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• v.4 no.1
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• pp.44-49
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• 2020

In this paper, a new method is presented to measure the refractive index of single plain glass or multilayered materials, based on a laser frequency-shifted confocal feedback microscope. Combining the laser frequency-shifted feedback technique and the confocal effect, the method can attain high axial-positioning accuracy, stability and sensitivity. Measurements of different samples are given, including N-BK7 glass, Silica plain glass, and a microfluidic chip with four layers. The results for N-BK7 glass and Silica plain glass show that the measurement uncertainty in the refractive index is better than 0.001. Meanwhile, the feasibility of this method for multilayered materials is tested. Compared to conventional methods, this system is more compact and has less difficulty in sample processing, and thus is promising for applications in the area of refractive-index measurement.

• Journal of Information Display
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• v.13 no.4
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• pp.139-143
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• 2012

In this study, optical simulation was used to compare three optical structures that could be applied to the typical organic light-emitting diode to increase the outcoupling efficiency. These were spherical scattering particles (treated as Mie scatterers) embedded in the glass substrate, microlenses formed on the glass substrate, and a diffusing layer (DL) with a Gaussian scattering distribution function inserted between the indium tin oxide (ITO) and the glass substrate. It was found that the application of microlens array and that of scattering particles in the glass substrate exhibited similar enhancements in the outcoupling efficiency when the density and the refractive index of the scattering particles were optimized. The DL located at the interface between the glass and the ITO further enhanced the efficiency because it could further extract the trapped light in the waveguide mode. The appropriate combination of these three structures increased the outcoupling efficiency to about 42%, which is much greater than the typical values of 15-20% when there is no optical structure for light extraction.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.56-62
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• 2003

The precision fabrication of glass is increasingly demanded for the latest industrial applications of spherical lenses, micro-optical components, and so on. In many cases, the surface roughness of glass is required to be minute for improving the optical characteristics. In this paper, machining characteristics of SF-5 glass and quarts glass are studied by using the ELID grinding process to get mirror surface and productivity compared with a general lapping process. A rotary type grinder with air spindle was used for the experiments. Mitutoyo surface tester and AFM were also used to measure the grinded surface of glass. As the results of experiments, they showed that the surface roughness (Ra) of SF-5 glass was under 7.8 nm and that of quartz glass was under 3.0 m using the # 8000 grinder. So, the possibility of highly efficient and accurate surface for optical components can be achieved by the ELID grinding process.