• Journal of The Korean Astronomical Society
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• v.36 no.3
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• pp.149-158
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• 2003

Deep surveys at mid-infared through submillimeter wavelengths indicate that a substantial fraction of the total luminosity output from galaxies at high redshift (z > 1) emerges at wavelengths 30 - 300${\mu}m$. In addition, much of the star formation and AGN activity associated with galaxy building at these epochs appears to reside in a class of luminous infrared galaxies (LIGs), often so heavily enshrouded in dust that they appear as 'blank-fields' in deep optical/UV surveys. Here we present an update on the state of our current knowledge of the cosmic evolution of LIGs from z = 0 to z $\~$ 4 based on the most recent data obtained from ongoing ground-based redshift surveys of sources detected in ISO and SCUBA deep fields. A scenario for the origin and evolution of LIGs in the local Universe (z < 0.3), based on results from multiwavelength observations of several large complete samples of luminous IRAS galaxies, is then discussed.

• Journal of KIEE
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• v.11 no.1
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• pp.46-50
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• 2001

In order to improve the luminous efficiency in ac PDP(Plasma Display Panel), we have suggested the new structures of sustain electrodes with waffle-type barrier ribs and the discharge current for a given pulse voltage has been decreased by eliminating the electrode area which has nothing to do with visible light emission area compared with conventional structure. As a result, the luminous efficiency was improved about 30% compared with the conventional structure.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.7
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• pp.314-318
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• 2003

This paper describes the construction, measurement, and characterization of an instrument for the distribution of luminous flux. This is done by measuring the flux around a light source while a detector and a source is rotating, and integrating it over an entire imaginary surface surrounding the source. We make a gonio radiometer to realize the scales of total luminous flux and geometrically integrate to get total spectral flux from standards of irradiance and illuminance. The uncertainties of a total flux in the gonioradiometry are 1.3%, and 0.4% below the standard lamps of NIST and NIM for each other.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.299-301
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• 2004

Inductively coupled plasma is commonly used for electrodeless lamp due to its ease of plasma generation. Optical characteristics significantly depend on the RF power and gas pressure of the plasma. This paper describes the measurement of luminous efficacy as a function of RF power and gas pressure with a goal of finding optimal operating conditions of the electrodeless lamp. The gas pressure was varied from 10 [mTorr] to 100 [mTorr] and the RF power was varied from 10 [W] to 120 [W]. It was found that the luminous flux tends to be decreased when argon pressure is increased, and the luminous flux is increased as RF fewer is increased. It was also found that the luminance efficacy is high when the argon pressure is low and when the RF power is low.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1710-1712
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• 2003

This paper analyzes the effects of various operating voltages on the luminous efficacy of high flux RGB LEDs. At first, their equivalent diode model are established from measurements of the V-I characteristics. Operating voltages of three types are applied to a simple LED circuit: DC, square-wave, and full-wave-rectified sine wave. As the result, DC voltage driving gives the hightest efficiency, but invokes much greater variation in the luminous flux and more shift in the peak wavelength.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.13-15
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• 2006

This paper describes the problem generated in PLS luminous flux measurement with integrating sphere. In RS case, we don't use the center position of the sphere but side position for flux test The difference of the lamp position makes the luminous flux difference of same light source. We confirmed the phenomenon with three other kinds of lamps and ensured the repeatability and reliability of this work at two laboratories. finally, the correction factor which should be applied for the PLS test at Side position was calculated.

• KIEAE Journal
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• v.7 no.5
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• pp.29-34
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• 2007

Discomfort glare from windows is an important issue in window and daylighting design. This study aims to investigate the effect of luminance difference between the lower and the upper part of a large glare source. Experiments were conducted using a luminous body divided into two parts, the upper part and the lower part. The degree of discomfort glare from the luminous body was examined. The result shows that the part with lower luminance is perceived as a glare source when the part has higher luminance then the background luminance. The degree of discomfort glare was estimated for the experimental conditions, and compared to the observations. The estimation was made using two methods: one summed the glare sensation for each section, and the other used the average luminance of the whole luminous body. The result of the comparison shows that the method using the average luminance has approximate values to the observations. Consequently, the use of the average luminance was proposed for evaluation of discomfort glare from non-uniform large glare sources.

• Current Optics and Photonics
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• v.3 no.1
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• pp.78-85
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• 2019

The remote phosphor structure has been proven to bear greater luminous efficiency than both the conformal phosphor and in-cup phosphor structures; however, controlling its color quality is much more challenging. To solve this dilemma, various researchers have proposed dual-layer phosphor and triple-layer phosphor configuration as techniques to enhance the display brightness of white LEDs (WLEDs). Likewise, this study picked one of these configurations to utilize in multichip WLEDs with five distinct color temperatures in the range from 5600 to 8500 K, for the purpose of improving the optical properties of WLEDs, such as color rendering index (CRI), color quality scale (CQS), luminous efficacy (LE), and chromatic homogeneity. According to the results of this research, the triple-layer phosphor configuration has superior performance compared to other configurations in terms of CRI, CQS, and LE, and yields higher chromatic stability for WLEDs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.9-16
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• 2005

The purpose of this research is to acquire emotional data on luminous source by measuring and evaluating human emotional response to the change of the optical feature of luminous environment Luminous sources used in actual architectural space were selected with the optical feature of luminous soured then to measure and analysis human emotional response on Luminous Source. As a result of that 1) In the result of performance measurement by the item of the clear vision of an optic function the fluorescent lamp of daylight indicated the most excellent Performance. 2) In the item of fatigue and stress, the metal halide lamp and mercury lamp showed the most 3) In $\ulcorner$ suitable in light$\lrcorner$, $\ulcorner$a similar with daylight$\lrcorner$ adjective of the amenity item the fluorescent lamp of daylight which color temperature was high turned up to be high also, in $\ulcorner$brilliant$\lrcorner$, adjective, the metal halide lamp and mercury lamp turned up to be low. 4) In the result of factor analysis, three factors $\ulcorner$activity$\lrcorner$, $\ulcorner$potency$\lrcorner$, $\ulcorner$evaluation$\lrcorner$ were abstracted and $\ulcorner$activity$\lrcorner$ factor has the most influential on evaluating the mood of interior space. 5) For the affection in the mood evaluation by each luminous sources, $\ulcorner$activity$\lrcorner$ factor was the most influential by metal halide lamp and fluorescent lamp of daylight, $\ulcorner$potency$\lrcorner$ factor was most influential by kind of incandescent lamp, $\ulcorner$evaluation$\lrcorner$ factor was most influential by fluorescent lamp of low color temperature.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.135-143
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• 2014

Purpose: To evaluate the blue-light blocking ratio and luminous transmittance of blue-light blocking lenses using the blue-light hazard function as specified in international standard. Methods: In order to calculate the blue-light blocking ratio and luminous transmittance for a total of 41 blue-light blocking lenses from 8 manufacturers, UV-Vis spectrophotometer was used for measuring the spectral transmittance of wavelengths from 380 to 780 nm. Blue-light blocking ratio was calculated using blue-light hazard function as specified in ANSI Z80.3:2010 and ISO 13666(or Korean Standard KS B ISO 13666:2004). Results: The range of the blue-light blocking ratio was from 9.3 to 96.8%, the range of the transmittance from 53.5 to 92.7%, and the range of the luminous transmittance from 58.0% to 98.1%. In general the blue-light blocking lens prepared by coating tended to have a higher luminous transmittance, while those prepared by tinting a higher blue-light blocking ratio. Conclusions: The behavior of the spectral distribution of lenses showed the possibility of the performance improvement in the blue-light blocking lenses. Manufactures need to acquire their own technology that can evaluate the performance of blue-light blocking lens based in international standard.