• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.424-432
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• 2007

Luminance properties of external electrode fluorescent lamps and optical components in backlight unit (BLU) and optical transmission rates of optical sheets, are investigated for LCD-TV of 32" in diagonal with WXGA level resolution (1366$\times$768). The luminance is measured in 12-lamps and 18-lamps of BLU. The luminance uniformity preserves about 85 % in the 12-lamps backlight, while the luminance of optical components and the efficiency of backlight in the 12-lamps are lower than those in the 18-lamps backlight. When the lamp luminance in BLU having 12-lamps and 18-lamps is normalized as 100 %, the relative luminance of a diffusion plate, a diffusion sheet, a prism sheet (BEF), a polarization sheet (DBEF), has a constant value without dependence on a lamp luminance. The relative luminance of optical components in 12-lamps BLU is lower than that in 18-lamps backlight. The light transmission rate, the relative luminance of liquid crystal display panel with the luminance 100 % of backlight, is 7.14 % in the use of DBEF and BEF, 6.12 % in the use of only DBEF, and 3.21 % in the use of only BEF. Those Data obtained in this experiment for the lamps and optical components, are the design parameters for the LCD backlight.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1387-1394
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• 2014

In a photoelastic experiment, it is necessary to know the material stress fringe constant of the photoelastic specimen to determine the stresses from the measured isochromatic fringe orders. The material stress fringe constant can be obtained using a simple tension specimen and/or a circular disk under diametric compression. In these methods, there is generally a need to apply numerous loads to the specimen in response to the relationship of the fringe order. Then, the least squares method is used to obtain the material constant. In this paper, the fringe orders that appear on a four-point bending specimen are used to determine the fringe constant. This method requires four photoelastic fringes obtained from a circular polariscope by rotating the analyzer to 0, ${\pi}/4$, ${\pi}/2$, and $3{\pi}/4$ radians. Using the four-point bending specimen to determine the material stress fringe constant has an advantage because measurements can be made at different locations by applying a constant load. The stress fringe constant measured with this method is within the range suggested by the manufacturer of the photoelastic material.

• The Journal of the Petrological Society of Korea
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• v.14 no.4 s.42
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• pp.195-211
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• 2005

The Kusandong Tuff, known as a representative key bed in the Cretaceous Gyeongsang Basin, is a crystal-rich tuff of pyroclastic flow and surge origin. It is 1-4 m thick and laterally extends for more than 200 km intercalated in the upper part of the Hayang Croup. Observations and analyses of the feldspar crystals in the tuff, using polarizing microscopes, EPMA, and BSE images, reveal that the plagioclase crystals in the tuff were completely albitized (>$97\%$ Ab) whereas those in the southernmost localities where the tuff is rich in fine ash matrix are unaltered or partly albitized. K-feldspars are partly albitized at all localities, irrespective of the matrix content of the tuff, Perthitic textures, chessboard twinning, albitization along micro-fractures and cleavages, and the relationship between matrix content and the degree of albitization suggest that feldspars in the Kusandong Tuff were albitized by Na-rich fluid after burial. Albitization is interpreted to start preferentially along micro-fractures and cleavages and be hampered in matrix-rich tuffs with a low permeability. Original composition of the plagioclases in the Kusandong Tuff is also interpreted to have ranged between oligoclase and andesine ($Ab_{62.5}-Ab_{83.3}$) before the albitization.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.11
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• pp.119-125
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• 1990

This paper describes fiber optic voltage sensor using EOM-BSO (Electro-Optic Modulator-Bismuth Silicon Oxcide). Transceiver has an electical/optical converter and an optical/electrical converter which consist of light emitting diode, PIN-PD, and electronic circuits. Multimode fiber cable of $100/140{\mu}m$ core/clad diameter is used for connecting the transceiver to fiber cable and fiber optic voltage sensor. Before our experiments, by applying the Maxwell equations and wave equations, We derive matrix equation on wave propagation in the BSO single crystal. And also we derive optimal equation on intensity modulation arising through an analyzer. According to experi-mental results, fiber optic voltage sensor has maximum $2.5{\%}$ error within the applied AC voltage of 800V. As the applied voltage increases, saturation values of voltage sensor also increase. This phenomenon is caused by optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optical rotatory power of BSO single crystal. And temperature dependence of sensitivity for fiber optic voltage sensor in the temperature range from$-20^{\circ}C\to\60^{\circ}C$ are measured within ${\pm}0.6{\%}$. And frequency characteristics of the voltage sensor has good frequency characteristics from DC to 100kHz.