• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.487-492
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• 2012

In this study we researched a spotlight in LED lighting. Ordinary LED spotlight was manufactured with characterized property of traveling straightness of LED light source, but multiple use of shell type LED, a yellow band has formed caused by light source interference between the LED. Also, there was a high miscellaneous light efficiency with losing light source homogeneity and efficiency due to light source control uneasiness. The study uses aspheric reflector and aspheric lens, so we can control the light source of LED spotlight with effectively and we reached surface light source by using COB/COM for LED module. Furthermore it can change its use by a reduced scale of light system. It has been designed to make its various application from low power consumption of bicycle lamp, up to high power consumption of automobile lamps and lighthouse.

• Journal of Broadcast Engineering
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• v.21 no.4
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• pp.538-551
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• 2016

At the on-site of broadcasting production, the light source of tungsten halogen has been used as a primary light source for representing video images. Although tungsten halogen light has drawn attention in terms of the color reproducibility which is more similar to the sun light than that of other light sources, meanwhile it had problems in energy efficiency. Recently, the LED light source with high efficiency and long lifetime of the energy source has started getting attention as a substitute light source at the broadcast field. Because of the unique light emission principles, compared with tungsten halogen, LED light source has different characteristics in the quality of the light projected from the light source and color reproduction of the video image through a camera. These characteristics cause the delayed introduction of the LED as the broadcast light source. In this study we measured the quality characteristics of the flatness of the color reproduction and light of the LED light source and will present the experimental data whether it is suitable as the broadcasting light source compared to a reference light source of tungsten halogen. In addition, we suggested the future challenges and standards which are needed to expand usage of LED as a broadcast light source.

• Journal of Radiation Industry
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• v.11 no.3
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• pp.157-165
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• 2017

In this paper, we calculate the light photons collection efficiency of large-volume plastic scintillation detector mainly used for radiation portal monitor (RPM). A Monte Carlo light photon transport code, DETECT2000, were used to quantitatively evaluate light collection efficiency of plastic scintillation detector. DETECT2000 calculated the placement of light collection efficiency based on the energy spectrum. We calculated the light collection efficiency relative to the position of the energy spectrum that proportional to the placement of the source. The $850{\times}285{\times}65mm^3$ size of polyvinyl toluene (PVT) scintillator was used for measurements. Through DETECT2000 simulation, the light collection efficiency of $5{\times}5$ arrays were calculated and verification was performed by comparing with experimentally measured. And then, the corrected MCNP simulation by applying the light collection efficiency in $21{\times}13$ arrays was compared and analyzed. Comparing the Monte Carlo simulation with measured results, it shows an average difference of 10.1% in $5{\times}5$ arrays. Particularly, about twice of the difference was found in the edge of first column, which coupled with PMT. In whole $5{\times}5$ array, the overall ratio was the same except for the first column. And then comparing the energy spectra of the $21{\times}13$ array with and without the light collection efficiency, it shows a difference of 6.69% in Compton edge area. The DETECT2000 based light collection efficiency simulation showed well agreement with the point source experiment. And comparing with measured energy spectra, we could compare the differences according to whether or not the light collection efficiency was applied. As a results, it is possible to increase the accuracy and reliability of Monte Carlo simulation results by pre-calculating the light collection efficiency according to the PVT geometry by using the DETECT2000.

• The Journal of the Korea Contents Association
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• v.21 no.6
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• pp.44-50
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• 2021

In this paper, we analyze the efficiency of light sources of CCFL and LED monitors. Cold Cathode Fluorescent Lamp (CCFL), which is widely used as a light source for LCD display, supplies a high voltage of 1,200[V] or more when it is initially driven. In addition, a constant normal voltage of 400 ~ 800[V] after lighting, and 3 ~ 6[ mA] is needed for a power circuit that can stabilize the current. Applying a high voltage causes a lot of stress on the inverter and generates a lot of heat in the cold cathode lamp, causing significant damage to the BLU (Back Light Unit), resulting in a burning phenomenon, which causes the screen to output normal colors when outputting the screen. We can not see the yellow output and the screen darkened. Therefore, in order to prevent such a symptom in advance, efficiency can be increased by using a Light Emitting Diode (LED) as the light source of the LCD display instead of a cold cathode fluorescent lamp (CCFL). As a result, it is shown that the LED method outperforms the CCFL method.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.107-109
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• 2007

LED is expected as an environmentally friendly light source with its good reliability and long lifetime. A few ten mW white LED can substitute for the indicator light source, and it is required to study several watt multi-chip semiconductor light sources in order to replace the light sources for general illumination such as incandescent lights and fluorescent lamps. Since the optical technology used for several mW white LED light source uses only 30% to 50% of the light, it is required to develop the design technology of optical system and lens to improve the efficiency more than 80% for insuring the high power of white LED. In this paper, we designed and fabricated new structure reflector to increase the efficiency.

• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.113-121
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• 2009

This study aims at designing and evaluating light source devices that can stably generate light with various wavelengths in order to make possible PDD using a photosensitizer and diagnosis using auto-fluorescence. The light source was a Xenon lamp and filter wheel, composed of an optical output control through Iris and filters with several wavelength bands. It also makes the inducement of auto-fluorescence possible because it is designed to generate a wavelength band of 380-420nm, 430-480nm, and 480-560nm. The transmission part of the light source was developed to enhance the efficiency of light transmission. To evaluate this light source, the characteristics of light output and wavelength band were verified. To validate the capability of this device as PDD, the detection of auto-fluorescence using mouse models was performed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.154-156
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• 2006

A few ten mW white LED can substitute for the indicator light source and it is required to study several watt multi-chip semiconductor light sources in order to replace the light sources for general illumination such as incandescent lights and fluorescent lanes. Since the optical technology used for several mW white LED light source uses only 30% to 52% of the light it is required to develop the design technology of optical system and lens to improve the efficiency more than 80% for insuring the high power of white LED. In this paper, we designed and fabricated new structure reflector to increase the efficiency and is easy to make high power multi-chip LED lamp.

• Applied Science and Convergence Technology
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• v.25 no.6
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• pp.133-137
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• 2016

The surface treatment of cover glass for conversion efficiency of photovoltaic cell is important to reduce reflectivity and to increase the incident light. In this work, random textured anti glare (RTAG) glass was prepared by wet surface coating method. Optical properties due to the changes of surface morphology of RTAG glass were compared and conversion efficiency of photovoltaic cell was researched. Grain size and changes of surface morphologies formed with surface etching time greatly affected optical transmittance and transmission haze. Current density (Jsc) were high at the condition when surface morphologies reflection haze were low and transmission haze were high. Jsc was $40.0mA/cm^2$ at glancing angle of $90^{\circ}$. Incidence light source was strongly influenced by surface treatment of cover glass at high incidence angle but was hardly affected light source at the low angle of incidence.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.4
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• pp.431-438
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• 2005

In order to apply the photocatalytic decomposition of aromatic VOCs, adsorbent prepared from MSWI fly ash was coated by $TiO_2$ solution to endow with photo-catalytic function. The effects of coating number, existence of light source and the type of $TiO_2$ solution used for coating were examined. Adsorbent coated with amorphous $TiO_2$ solution showed higher adsorptivity than adsorbent coated with crystal $TiO_2$ solution. Without light source, breakthrough curve of photo -catalyst absorbent for VOCs removal was similar to that of absorbent made from MSWI fly ash. On the other hand, breakthrough time was enlarged with light source and total removal efficiency of benzene and toluene was also increased. It can be explained as photo-decomposition effect of $TiO_2$ photo-catalyst. Total removal efficiency of benzene and toluene was increased according to the increase of coating number with light source. It was due to the effect of adsorption and photo reaction of photo-catalytic adsorbent. But total removal efficiency of benzene was lower than that of toluene. Because benzene was removed more effectively than toluene by adsorption, but photo - decomposition effect oi toluene was more high than benzene.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.578.1-578
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• 2001

The aim of this study was to evaluate the efficiency of the recently introduced light curing units to polymerize a light curing resin composite. Four light curing units XL 3000, Optilux 500 for halogen light source, Apollo 95E for plasma arc and Easy cure for LED (blue-light Emitting Diode) were evaluated. Radiometer was used for measure the light intensity.(omitted)