• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.836-841
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• 2004

This paper describes ASIC design for brightness revision control, A LED Pixel Matrix (LPM) design and LPM in natural color LED vision. A designed chip has 256 levels of gradation correspond to each Red, Green, Blue LED pixel respectively, which have received 8bit image data. In order to maintain color uniformity by reducing the original rank error of LED, we adjusted the specific character value 'a' and brightness revision value 'b' to pixel unit, module unit and LED vision respectively by brightness characteristic function with 'Y=aX+b'. In this paper, if designed custom chip and brightness revision control method are applied to manufacturing of natural color LED vision, we can obtain good quality of image. Furthermore, it may decrease the cost for manufacturing LED vision or installing the plants.

• Journal of the Semiconductor & Display Technology
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• v.19 no.2
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• pp.22-25
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• 2020

Deep red EuSi₂O₂N₂ phosphors were synthesized under various sintering gas pressures (1 atm, 2 atm, and 3 atm). They were in good agreement with the standard EuSi₂O₂N₂ ICSD card # 41-6046 (a monoclinic crystal system with space group of P2₁/a). Their photoluminescence intensities were significantly increased with increasing the gas pressures. They showed a broad band emission peaking at 680 nm due to 4f⁶5d¹ - 4f⁷ of Eu²⁺ ion, which can be efficiently excited in the visible range up to 550 nm. The best one at 3 atm was applied for red LED based on blue chip, which showed the strong deep red emission.

• Journal of Mushroom
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• v.11 no.4
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• pp.226-229
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• 2013

This study was carried out to elucidate suitable wavelength of light during development of fruit body in Lentinula edodes. The four colors of LED(Light Emitting Diode), blue, green, red and yellow, were irradiated for formation of fruit-body. The effect of color of LED at all growth stage, the lightness of cap showed darker in blue and green LED irradiation than that of red and yellow LED. The longer stipe were resulted in longer wavelength. And the activity of anti-oxidant did not showed big differences according to LED wavelength. We obtained higher commercial yields and lower ratio of abnormal fruit body in green LED than those in control(fluorescent lamp).

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.51-54
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• 2016

This paper present a method which resolves an optical discontinuity in bezel of digital signage using light guide film. On a polycarbonate film, a light guide film is bonded to produce refraction, reflection, diffraction of light. Arc shaped light guide film is assembled on the top LED light sources (red and green) to see light propagation through the film. When the two light sources (red and green) are mechanically attached at the end of the film, optical convergence brings new colors which have light wavelength between red and green. This result indicates that the light waveguide method could solve the light discontinuity on bezel of the digital signage system.

• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.99-102
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• 2016

The phototactic behavioral responses of Tribolium castaneum adults to light-emitting diodes (LEDs) of seven different wavelengths were determined under various conditions (light exposure times, light sources, and luminance intensities) and compared with those of a black light bulb (BLB) under laboratory conditions. Based on the attractive rate (%) of T. castaneum adults under optimal conditions (50 lx and an 48 h exposure time) in the dark, red LED ($625{\pm}10nm$) exhibited the highest potential attractive rate (97.8 %), followed by yellow ($590{\pm}5nm$, 68.9 %), green ($520{\pm}5nm$, 55.6 %), infrared (IR) (730 nm, 54.4 %), white (450-620 nm, 41.1 %), blue ($470{\pm}10nm$, 34.4 %), and ultraviolet (UV) (365 nm, 0.06 %) LEDs. In comparison, red LED (97.8 %) was approximately 3.4 times more attractive to T. castaneum adults than the BLB (28.9 %). These results indicate that a red LED trap could be useful to control T. castaneum adults.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.184-184
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• 2022

This study was aimed to evaluate the antioxidant activity and bioactive property of extracts from a purple-colored wheat variety 'Arriheuk' (Triticum aestivum L.) wheatgrass, affected by light emitting diode irradiation (LED). The wheatgrass was cultivated for 10 days after sowing in a growth chamber under the following LED conditions: R1B1 (Red:Blue = 1:1), R7B3 (Red:Blue = 7:3), and R3B7 (Red:Blue = 3:7). We examined antioxidant activity of the hot water extracts of wheatgrass using DPPH and ABTS free radicals scavenging assays. At the concentration of 10,000 ㎍/ml, the extract from R1B1 showed the highest DPPH free radical scavenging activity(79.29%), but its ABTS free radical scavenging activity was the lowest(32.0%). To evaluate bioactive property of the wheatgrass, we examined the change of natural killer (NK) cell activity affected by the wheatgrass extracts in vitro. At the concentration of 500㎍/ml, NK cell activity was most highly enhanced by the extract from R1B1(181.6%), and the activity was 176.1% (R7B3) and 144.6%(R3B7), respectively. These results suggest that the functional property of 'Arriheuk' wheatgrass would be enhanced by LED irradiation condition.

• Journal of Life Science
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• v.29 no.3
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• pp.311-317
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• 2019

To investigate the effects of light on growth in fish, olive flounder (Paralichthys olivaceus) were reared under four kinds of monochromatic light-emitting diodes (LEDs) at violet (400 nm), blue (465 nm), green (508 nm), and red (635 nm) wavelengths, along with a white fluorescent lamp as control. The rearing experiments were carried out with 15 fish per tank under different wavelength illumination at the same intensity. After rearing the fish under a 12 hr:12 hr light:dark photoperiod for 60 days, percentage increases in weight gain of $269.92{\pm}13.02$, $363.21{\pm}3.74$, $433.22{\pm}4.83$, $290.17{\pm}11.83$, and $340.74{\pm}26.58%$ and increases in specific growth rates (SGR) of $2.18{\pm}0.06$, $2.56{\pm}0.07$, $2.79{\pm}0.01$, $2.27{\pm}0.05$, and $2.47{\pm}0.10$ were observed in fish grown under the illumination of red, blue, green, and violet LEDs and the white fluorescent light, respectively. The results show faster growth in fish reared under green LEDs, but slower growth in those reared under red light. Differences in most blood parameters were minor, aside from an increased level of glutamic oxaloacetic transaminase in the fish grown under red LED illumination. Histological analysis of the retina showed few changes in the ratio of photoreceptor layer thickness to total retina thickness in fish reared under the green LEDs compared to those in other illumination groups. These results indicate that green LED light can foster increased growth in olive flounder with no distinct harmful effects on their light-sensitive photoreceptor layers.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.42-47
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• 2013

BACKGROUND: As improved LEDs (Light Emitting Diode) industry and decreased the price of LEDs in Korea, some farmers try to using the RED LEDs in green house and open field to increase the production of crop under bad weather condition. The aim of this study is to find out the effect of RED and FAR-RED LEDs lighting on the fruit quality of twelve-year old 'Hongro'/M.26 apple during night after sunset. METHODS AND RESULTS: FAR-RED (730nm, 2 and 4 hour) and RED (620nm, 2 and 4 hour) with 20 LED/PCB were treated in orchard for 16 weeks from June 10 to October 10 in 2009 and 2010 with control as an comparison. In our experiments, leaf weight was significantly higher in RED LEDs than control, tended to be decreased as times of FAR-RED lighting increased. Fruit weight was increased more in RED LEDs than control in 2009 and 2010, but decreased in FAR-RED lighting compared to control in 2010. Firmness and Hunter's a value of fruit were increased in FAR-RED lighting with 2 and 4 h than control. Soluble solid contents were higher in 2 h RED and 2, 4 h FAR-RED LEDs compared to control in 2009, there was no significant difference in 2010. Acid contents were no difference among the treatments. CONCLUSION(S): In our results, we found that RED LEDs was more helpful to increase the fruit weight and FAR-RED LEDs promote to be higher hunter a value of fruit skin. So, we thought that it is necessary to more study if mixed of RED and FAR-RED lighting is more helpful to promote fruit quality of 'Hongro' apple than single lighting of RED or FAR-RED LEDs respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.274-277
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• 1996

This paper describes the realization of the full-color to the degree of nearest white light by compounding high brightness Red, Green and Blue LEDs with appropriate proportional index. Once these three colors; red, green and blue are mixed, they are genearlly additive mixing and produce white light color contrasted to negative mixing. The luminous efficiency is defined as the product of the efficiency(lm/w), which indicates the degree of perceptual response by the human eye to unit energy(W) of light emitted by an active display devises and as the conversion efficiency of the device from electric power consumed to optical energy produced. We will deduce the each number of LEDs theoretically and design several shapes of LED displays for the full-color. Finally theoretical predictions will be compared with the measured data with different type of display designs.

• Journal of Information Display
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• v.2 no.2
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• pp.45-51
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• 2001

Four types of conjugated polymers, poly(MEHPV-PV), poly(MEHPV-BPV), poly(MEHPV-AV) and poly(PZV-AV) were synthesized by Homer-Emmons reaction using potassium tert-butoxide. The Homer-Emmons reaction gave electroluminescent(EL) copolymers in good yield. Of the EL copolymers synthesized, poly(PZV-AV) containing phenothiazinylene vinylene and anthrylene vinylene as repeat unit exhibited red color in the light emitting diode(LED) which was very close to the NTSC standard red. Besides, double layer LED made with $Alq_3$ electron transport layer exhibited both enhanced emission intensity and efficiency compared to the single layer LED.