• Korean Journal of Optics and Photonics
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• v.12 no.2
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• pp.103-108
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• 2001

In this paper, we designed and made the scanned point detecting system for 3-dimensional measurement of the light emitted from plasma display panel (PDP) , and we measured and analyzed 3-dimensional light emitted from a real PDP by using this scanned point detecting system. The scanned point detecting system has a point detector with a pinhole. The light emitted from the source at the in-focus position can pass through the pinhole and be collected by detector. The light from other sources at outof-focus positions is focused at points in front of or behind the pinhole, and thus it is intercepted by the pinhole. Therefore, we can detect light information from a particular point of a PDP cell of 3-dimensional structure. We know the electric field distribution inside the PDP cell from the 3-dimensionallight intensity distribution measured by using the scanned point detecting system. As the Z axial measurement increases, the intensity of light detected increases and intensity of light detected on the inside edge of the ITa electrode is larger than outside edge of the ITa eletrode and gap of the ITa electrodes. Also, as the measurement point moves from one barrier rib to another, the detected light is weaker near to the barrier ribs than at the center between the barrier ribs. The emitted light is concentrated at the center between barrier ribs. ribs.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.965-968
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• 2007

The effect of the modification of the front surfaces of flat fluorescent lamps (FFLs) on the light-output distribution has been investigated by using a ray tracing method and several kinds of microlenses. It was found that microlenses have substantial effects on the light-output distribution, which might be used to reduce the number of optical films in the FFL-backlight unit for LCD applications.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.2
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• pp.246-251
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• 2016

The use of security lighting that emits spill light is considered a cause of light trespass problems in the residential areas. Therefore, a cutoff panel was installed as an alternative way to reduce light trespass. On the other hand, it has another problem in that it is less effective and is not good enough for aesthetics and safety. In this study, a light cutoff panel was designed and manufactured to reduce the light trespass, and the structure of a proper light cutoff panel was studied. Using a goniophotometer, the light distribution file (IES file) was extracted and the characteristics of light distribution were analyzed using the RELUX program. The results showed that the reduction of spilt light in the backward direction was decreased significantly for all types of light cutoff panels except the coated globe. In the case of a black powder coated light cutoff panel, the forward light caused by light reflected from the surface of the light cutoff panel was also reduced, which means that the black powder coated light cutoff panel is effective in the performance of light cutoff in the forward and backward directions. In addition, the coated glove increased the spilt light in the forward and backward directions because it reflects the upward light to go down. A 90 % accuracy between the measurement value of light trespass and the expected value of the light trespass was obtained from a simulation.

• Journal of the Institute of Convergence Signal Processing
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• v.2 no.2
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• pp.39-46
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• 2001

In this paper we propose a new method that can be estimation the spectral power distribution of the light source from three-band images. the light source is estimated by dividing the reflected spectral power distribution of the maximum achromatic region(L(λ)) by the corresponding surface reflectance(Ο(λ)). In order to obtain reflected spectral power distribution of the maximum achromatic region from three-bend images, a modified gray world assumption algorithm is adapted. And the maximum surface reflectance is estimated using the principal component analysis method along with achromatic population. The achromatic population is created from a set of given Munsell color chips whose chroma vector is less than threshold. Cumulative contribution ratio of principal components from the first to the third for classified achromatic population was about 99.75%. The reconstruction of illumination spectral power distribution by using achromatic population and three-band digital images captured under various light source was examined, and evaluated by RMSE between the original and reconstructed illumination spectral power distribution. This work was supported by grant No (2000-1-30200-005-3) from the Basic Research Program of the Korea Science & Engineering Foundation.

• Particle and aerosol research
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• v.9 no.4
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• pp.253-260
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• 2013

For a vertical atmospheric aerosol distribution measurement, a very compact and light particle sampling package is developed. This package includes a compact optical particle counter (Hy-OPC), a light and small condensation particle counter (Hy-CPC), sensors (GPS, wind velocity, temperature, humidity), and a communication and system control board. This package is attached to He balloon and the altitude is controlled by a winch. Using this system the vertical particle size distribution was measured. The test results showed that the ground base atmospheric particle measurement result may be a lot different from that high above the ground.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1178-1182
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• 2011

The best methods for distribution controled of LED lighting fixtures is control to designed LED chip array, lens and reflector. However, lens design need distribution design to reflector for low-wattage LED lighting because of difficulty of production and reduction of light efficiency. In addition, it needs maximize of thermal performance to improve the efficiency and reliability of device. As a result, for the height of reflector 40[mm] and Inclination 25[$^{\circ}$], we can see the best distribution properties, and, in the thermal properties, junction temperature MCPCB 62.9 [$^{\circ}C$], FR4 PCB 89.6 [$^{\circ}C$], FR4 PCB from Via-hole is 63.1 [$^{\circ}C$]. it may improve for thermal properties for makes the Via-hole.

• 한국해양학회지
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• v.9 no.2
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• pp.1-9
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• 1974

The vertical distribution and diurnal migration of Evadne nordmanii has been studied at different stations in the Irish Sea. There are many reports that the migrations of planktonic animals tend to be hampered by thermoclines and haloclines. Physical and chemical factors were compared with vertical distribution and diurnal migrations of the animal. Evadne must be essentially an epiplanktonic form with the ability to endure strong light intensity. The animals generally migrated to the very surface layer from their shallow day strata with the decreased of light intensity. During the night their distribution seems rather random or even throughout all the layers, with a tendency to concentrate at the bottom layers, when the water was homogeneous physically and chemically. E. nordmanii may penetrate minor thermoclines and haloclines, but they may avoid chemically distinct waters or possibly currents.

• Journal of Applied Reliability
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• v.9 no.1
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• pp.59-69
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• 2009

LEDs have rapidly replaced old light devices such as incandescent or fluorescent lamps, and have been widely applied in general lighting, signals, automobile, signs and others. Since LEDs are for both indoor and outdoor use, temperature and humidity inevitably affect its reliability. We explain the result of the degradation life test on LEDs, and guide to reliability analysis procedure. Analysis on reliability measures are performed by Weibull++6 program, and a common shape parameter of Weibull distribution on the LED is suggested. Also, we make a description of reliability analysis procedures for the degradation data using collected test data from degradation tests. Reliability analysis procedures are consisted of estimating degradation models and failure time, verifying of distribution and parameters of the distribution, and estimating of reliability measures. Finally, this paper suggests reliability analysis method for light characteristics on LEDs.

• Journal of Astronomy and Space Sciences
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• v.7 no.1
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• pp.57-69
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• 1990

The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 $AA$ to 3050 $AA$. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

• Current Optics and Photonics
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• v.4 no.2
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• pp.141-147
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• 2020

To understand the cause of the high light transmittance of the human eye, the optical effects of the collagen fibers of the stroma layer, which constitute the majority of the cornea, were analyzed. These collagen fibers, approximately 20 nm in diameter, have a regular arrangement. Accordingly, the optical properties of the collagen fibers and the fiber layer were analyzed by simulation. A standing wave was formed in the incident space by the overlapping incident light and the light reflected by the plate. In addition, it was confirmed that when the collagen fibers are arranged in a layer, the light transmittance periodically changes, depending on the number of fiber layers. The standing wave was formed in the incident space, and the light's intensity distribution was changed by the nanoscale collagen fibers in the section with the collagen layer, which affected the transmittance. To explain this phenomenon, the collagen fiber was defined as a second light source, and an attempt was made to describe the simulation results in terms of overlap of the incident light with the light emitted from the collagen fiber.