• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.12
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• pp.5023-5028
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• 2010

In this paper, an image based LED design simulator is proposed to reduce LED design cost mostly contingent on a design expert. Current techniques about LED design schemes have mostly treated text-based LED simulators. The proposed method is to provide novel and easy simulator for LED designers. At first, image filters including histogram equalization, bicubic interpolation. and scaling are employed. Color mapping and special effects are added as well. Experimental results classified into several categories along with running times are shown to validate the proposed methods.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.2
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• pp.163-170
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• 2016

The purpose of this study was to verify the emotional response of user to LED light colors in healing bed system in cypress tree. Eight colors of LED light were provided including red, orange, yellow, green, blue, indigo, violet and white. And three illumination color temperature were provided including 3,000K, 5,000K, 8,000K. Seven subjects in their twenties were involved without the medical history of eyes and heart disorders. The subjects were exposed to LED lighting during 5 minutes and their emotional response was evaluated through the following: first, at the physiological effect heart rate variability(HRV) was measured during the stimulation; second, at the emotion level the subjects were asked about lighting color and color temperature through a survey. Results, lower color temperature of 3,000K and green color shows high value on HRV. We have found that there is a difference of physiological and emotion level effect depending on color stimulus. This study could be applied to reference data to analysis of a decrease in fatique and charges of brain waves for color stimulus.

• Journal of Mushroom
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• v.15 no.4
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• pp.259-263
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• 2017

In this study, we investigated the morphological characteristics and antioxidant ability of mushroom cultivar Lentinula edodes 'Nongjingo' fruiting bodies after exposure to various light conditions. Color differences between mushrooms treated with mixtures of LED light revealed that mushrooms displayed lighter color shades when compared to the control group (fluorescent light treated mushrooms). Redness increased and yellowness decreased after exposure to all treatments other than the fluorescent control. Measurement of growth characteristics of 'Nongjingo' fruiting bodies showed increases after exposure to all mixed LED treatments. In addition, the uniformity of fruiting bodies was higher when using LED light compared to fluorescent light. The measurement of stem diameters did not show a significant difference between the treatments, however, diameters were slightly larger with exposure to white-green LED. Moreover, stem length was longer in the mixed LED treatments when compared to those exposed to fluorescent light. Examination of the ratio of stem diameter to stem length revealed that the diameter of the stem was greater than the length. The antioxidant activity of water extracts made from Nongjingo fruiting bodies grown under mixed LED conditions was compared to those from mushrooms grown under fluorescence light conditions. The highest antioxidant activity was observed from mushrooms treated with white LED; however, no significant difference was found between mushrooms exposed to white-green LED compared to white-blue LED. The treatment showed higher antioxidant ability than vitamin C. Our results confirm that treatment of white LED and white-blue LED affects the growth and antioxidant ability of Nongjingo mushroom fruiting bodies.

• Journal of Mushroom
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• v.21 no.3
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• pp.132-139
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• 2023

Light plays an important role in fruit-body development and morphology during Pleurotus spp. cultivation. To understand the effects of light color on fruit-body properties, we evaluated the fruit-body characteristics of Pleurotus spp. Varieties cultivated under blue, red, and purple LED light sources. The main results are as follows: The overall fruit-body shape showed differences depending on the color of the LED light. The fruit-bodies of mushroom cultivated under blue and purple light were generally similar to the mushroom shapes typically produced, while those of mushroom cultivated under green light were abnormally shaped, probably due to the absence of effective light source. The average cap lightness of mushrooms cultivated under blue, green, and purple LED lights was 57.0, 57.4, and 59.4, respectively. The average cap lightness of all varieties except Wonhyeong1ho and Hwang-geumsantari cultivated under the three LED light sources were statistically significantly different (P<0.05). The cap redness varied significantly depending on the LED lighting and variety. Only Gonji7hoM, the cap color mutant of Gonji7ho, showed negative cap redness values under all three LED light sources. Among the eight varieties excluding Gonji7ho, the highest cap redness was observed when cultivated under the blue LED. The average harvest weight of the varieties cultivated under purple, blue, and green LED light were 68.0, 58.3, and 50.1 g, respectively. The yield of Gonji7ho, the mushroom variety with the highest yield, cultivated under blue, green, and purple LED light were 92.8, 77.1, and 98.6 g, respectively. The earliness when grown under the purple, blue, and green LED lights were 5.3, 5.8, and 5.8 days, respectively. Among the varieties, six, three, and two cultivars showed the shortest earliness under the purple, green, and blue LED, respectively. The fruit-body lengths were 66.4, 51.8, and 46.8 mm when cultivated under green, purple, and blue lights, respectively. These results are expected to serve as a foundation for producing mushrooms with traits demanded in the market.

• Korean Journal of Optics and Photonics
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• v.24 no.2
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• pp.64-70
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• 2013

In this paper, two white light emitting diodes(LEDs) were manufactured by using two kinds of yellow phosphor, YAG:Ce and $(Sr,Ba)_2SiO_4:Eu$, and their spectroscopic properties were compared and analyzed. We found that the asymmetric double sigmoidal function can be applied to both white LEDs to obtain the center wavelength, the half width, and the skewness parameters. According to this analysis, the half width of the emitting spectrum of silicate phosphor was smaller than that of YAG phosphor, indicating smaller color rendering index. However, the silicate phosphor exhibited better color stability depending on the driving current than the YAG phosphor. The current dependence of the luminous efficacy of both white LEDs was investigated, which showed that efficacy decreased monotonically with current. The efficacy of the silicate-based white LED was lower than that of the YAG-based LED by about 10~12 lm/W.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.270-271
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• 2007

LED를 이용한 램프개발 다목적 램프, 실내 조명용이나 전광판의 디스플레이용, 간판의 채널래터용으로 이용가능, LED 램프의 효율을 향상을 위해 반사판 설계, 3차원 설계로 반사판 설계 후 포토피아로 시뮬레이션 반사판과 글로브 형태 및 재질에 따른 광효율시뮬레이션

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.743-744
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• 2010

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.12
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• pp.174-182
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• 2015

In this paper, we developed the small size RGB sensor that recognizes a long distance using a low-cost color sensor. Light receiving portion of the sensor was used as a camera lens for far distance recognition, and illuminating unit was increased the strength of the light by using a high-power white LED and a lens mounted on the reflector. RGB color recognition algorithm consists of the learning process and the realtime recognition process. We obtain a normalized RGB color reference data in the learning process using the specimens painted with target colors, and classifies the three colors using the Mahalanobis distance in recognition process. We apply the developed the RGB color recognition sensor to a prototype of the part classification system and evaluate the performance of its.

• Information Display
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• v.3 no.4
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• pp.13-16
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• 2002

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1668-1674
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• 2011

Door Inside Lamp of railway rolling stock is installed on interior of the side doors and illuminated at door opening and closing, isolation and fault. So drivers or passengers can notice the door status visually. In the past, a single color or Bi-color LED Lamps have been using and one ~ multiple lamp was used to implement the feature according to client's requirements. (Example: Total of between 2 and 4 lamps are required for the Warning / Emergency operation / Isolation / Fault.) However these design is not easy to apply if there is the mounting space restrictions and the problems such as rising costs can be caused. In addition, it has vulnerability from point of view aesthetic aspects. Therefore the lamp type has been required that has small size and number of colors in order to resolve these problems. Recently multi LED type door status indication lamp have been developed that can meet the requirements and this lamp has been applied in many railway projects. In this study, I'll introduce the general characteristics and mechanical & electrical characteristics of multi LED type door status indication lamp to help development of this kinds of lamp.