• 한국전기전자재료학회논문지
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• 제36권3호
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• pp.266-274
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• 2023

Recently, sterilization technology has received increasing interest due to the COVID-19 pandemic and required safety precautions. Particularly, sterilization devices using near ultraviolet (UV) with a 405 nm wavelength are also drawing attention. It has a UV-C wavelength and other sterilization effects. Its blue-colored light on the boundary between UV and visible light is used as a light-emitting diode (LED) lamp for 405 nm sterilization, owing to its longer wavelengths than UV rays. However, the 405 nm wavelength contains blue light that can damage the eyes and skin during prolonged exposures and affect the emotional and biological parts of the body. Currently, 405 nm sterilization LED light registers are circulating in the market. However, they have not undergone safety tests for blue-light hazards. Thus, with the active distribution of sterilization LED lights, solid safety standards and management systems are essential to protect users from blue-light hazards. Accordingly, in this study, we conducted spectral radiance and spectral radiative luminance tests on 405 nm sterilization LED registers available in the market by the measurement criteria of IEC 62471. Safety standards must be established to secure users' safety against blue light hazards at a time when 405nm sterilization LED lights are actively distributed due to COVID-19.

• 원예과학기술지
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• 제35권2호
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• pp.178-187
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• 2017

인공 광원에 따른 rocketsalad(Eruca sativa L.) 내 GSL 함량을 조사하였다. 실험에 사용한 광원의 종류는 자연광(Control-1 또는 2), Red LED, Blue LED, Mix(R+B) LED(Red LED+Blue LED), White LED, Fluorescent Lamp(FL), Fluorescent Lamp+UV-C(FL+UV-C). 실험은 식물 생장기 대수 제한 때문에 [실험 I;Control-1, Red LED, Blue LED, Mix(R+B) LED]과 [실험 II;Control-2, White LED, FL, FL+UV-C]로 구분하여 수행하였다. 그 결과, Red LED와 FL에서 rocket salad의 잎의 길이의 증가율이 가장 높았다. 그러므로 Red LED와 FL이 rocketsalad의 성장과 관계가 있음을 확인했다. Rocketsalad로부터 총 7종류의 GSLs(glucoraphanin, diglucothiobeinin, glucoerucin, glucobrassicin, dimeric 4-mercaptobutyl GSL, 4-methoxy glucobrassicin, gluconasturtiin)를 분리 및 동정하였다. [실험 I]에서 총 GSL 함량은 Red LED(4.30)에서 가장 높고 Blue LED($0.17{\mu}mol{\cdot}g^{-1}\;DW$)에서 가장 낮았다. [실험 II]에서 총 GSL 함량은 FL(13.45)에서 가장 높고 FL+UV-C($0.39{\mu}mol{\cdot}g^{-1}\;DW$)에서 가장 낮았다. 특히 Rocket salad의 강한 향과 매운 맛을 돋아주는 dimeric 4-mercaptobutyl 함량은 [실험 II]에서 Control-2에 비해 FL과 White LED가 각각 14.9, 3.2배 증가했다. 따라서 Red LED, White LED, FL은 rocket salad의 GSL 축적에 영향을 주었다고 판단된다.

• 한국세라믹학회지
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• 제41권8호
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• pp.573-577
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• 2004

Eu$^{2＋}$를 활성제로 Sr$_3$MgSi$_2$ $O_{8}$ 청색 형광체를 합성하고, Sr$_3$MgSi$_2$ $O_{8}$：Eu 청색 형광체를 InGaN의 UV chip에 도포하여 청색 LED Lamp를 제조하였다. 제조된 청색 LED Lamp는 405nm와 460nm에서 두 개의 파장을 나타내고 있다. 405nm의 파장은 InGaN의 활성영역으로부터의 radiative recombination 때문에 나타나는 피크이다. 여기에서 나오는 405nm의 발광은 본 Sr$_3$MgSi$_2$ $O_{8}$：Eu 청색 형광체의 여기원으로 사용된다 460nm에서의 발광 밴드는 Sr$_3$MgSi$_2$ $O_{8}$ 모체내에서 Eu$^{2＋}$ 이온의 radiative recombination에 의한 것이다. 발광효율이 좋은 Sr$_3$MgSi$_2$ $O_{8}$：Eu 청색 형광체를 이용하여 UV 청색 LED Lmp를 제조한 결과, 에폭시와 청색 형광체의 무게 비율이 1$.$0.202에서 가장 좋은 광도값을 얻을 수 있었다. 이때 색좌표는 CIE x=0.1417, CIE y=0.0683이었다.

• 한국세라믹학회지
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• 제43권5호
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• pp.304-308
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• 2006

We have synthesized a $Eu^{2+}-activated\;Sr_3MgSi_2O_8$ blue phosphor and $(Sr,Ba)_2SiO_4$ yellow phosphor and prepared white LEDs by combining these phosphors with a InGaN UV LED chip. Three distinct emission bands from the InGaN-based LED and the two phosphors are clearly observed at 405 nm, 460 nm and at around 560 nm, respectively. The 405 nm emission band is due to a radiative recombination from a InGaN active layer. This blue emission was used as an optical transition of the $Sr_3MgSi_2O_8:Eu$ blue phosphor and $(Sr,Ba)_2SiO_4:Eu$ yellow phosphor. The 460 nm and 560 nm emission band is ascribed to a radiative recombination of $Eu^{2+}$ impurity ions in the $Sr_3MgSi_2O_8:Eu$ and $(Sr,Ba)_2SiO_4$ host matrix. As a consequence of a preparation of UV White LED lamp using the $Sr_3MgSi_2O_8:Eu$ blue phosphor and $(Sr,Ba)_2SiO_4:Eu$ yellow phosphor, the highest luminescence efficiency was obtained at the ration of epoxy/two phosphor (1/0.2361). At this time, the CIE chromaticity was CIE x = 0.3140, CIE y = 0.3201 and CCT (6500 K).

• 한국세라믹학회지
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• 제43권3호
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• pp.169-172
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• 2006

We have synthesized a $Eu^{2+}-activated\;{(Sr,Ba)}_2SiO_4$ yellow phosphor and investigated the development of blue LEDs by combining the phosphor with a InGaN blue LED chip (${\lambda}_{em}$=405 nm). The InGaN-based ${(Sr,Ba)}_2SiO_{4}:Eu$ LED lamp shows two bands at 405 nm and 550 nm. The 405 nm emission band is due to a radiative recombination from a InGaN active layer. This 405 nm emission was used as an optical transition of the ${(Sr,Ba)}_2SiO_{4}:Eu$ phosphor. The 550 nm emission band is ascribed to a radiative recombination of $Eu^{2+}$ impurity ions in the ${(Sr,Ba)}_2SiO_4$ host matrix. In the preparation of UV Yellow LED Lamp with ${(Sr,Ba)}_2SiO_{4}:Eu$ yellow phosphor, the highest luminescence efficiency was obtained at the epoxy-to-yellow phosphor ratio of 1:0.45. At this ratio, the CIE chromaticity was x=0.4097 and y=0.5488.

• Journal of Applied Biological Chemistry
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• 제59권2호
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• pp.95-98
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• 2016

Phototactic behavioral responses of the Indian meal moth, Plodia interpunctella ($H{\ddot{u}}bner$), adults were determined to different light-emitting diodes (LEDs) of seven wavelengths, and their behavioral responses were compared to that using a commercial luring lamp (BLB) under laboratory conditions. Based on the attractive responses under optimal light conditions (60 lx luminance intensity and 30 min light exposure time), the green LED ($520{\pm}5nm$) showed the highest attractive rate ($520{\pm}5nm$, 52.2 %), followed by the blue LED ($470{\pm}10nm$, 33.9 %), the yellow LED ($590{\pm}5nm$, 32.2 %), BLB (28.9 %), UV LED (365 nm, 22.8 %), the red LED ($625{\pm}10nm$, 14.5 %), the white LED (450-620 nm, 10.6 %), and IR LED (730 nm, 9.5 %). In addition, the green LED to P. interpunctella adults was approximately 1.81 times more attractive than BLB. These results indicate that the green LED could be most useful for monitoring of P. interpunctella adults.

• Environmental Engineering Research
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• 제18권1호
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• pp.21-28
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• 2013

In this study, the applicability of visible light-emitting-diodes (LEDs) to the photocatalytic degradation of indoor-level trichloroethylene (TCE) and perchloroethylene (PCE) over N-doped $TiO_2$ (N-$TiO_2$) was examined under a range of operational conditions. The N-$TiO_2$ photocatalyst was calcined at $650^{\circ}C$ (labeled N-650) showed the lowest degradation efficiencies for TCE and PCE, while the N-$TiO_2$ photocatalysts calcined at $350^{\circ}C$, $450^{\circ}C$, and $550^{\circ}C$ (labeled as N-350, N-450, and N-550, respectively) exhibited similar or slightly different degradation efficiencies to those of TCE and PCE. These results were supported by the X-ray diffraction patterns of N-350, N-450, N-550, and N-650. The respective average degradation efficiencies for TCE and PCE were 96% and 77% for the 8-W lamp/N-$TiO_2$ system, 32% and 20% for the violet LED/N-$TiO_2$ system, and ~0% and 4% for the blue LED/N-$TiO_2$ system. However, the normalized photocatalytic degradation efficiencies for TCE and PCE for the violet LED-irradiated N-$TiO_2$ system were higher than those from the 8-W fluorescent daylight lamp-irradiated N-$TiO_2$ system. Although the difference was not substantial, the degradation efficiencies exhibited a decreasing trend with increasing input concentrations. The degradation efficiencies for TCE and PCE decreased with increasing air flow rates. In general, the degradation efficiencies for both target compounds decreased as relative humidity increased. Consequently, it was indicated that violet LEDs can be utilized as energy-efficient light sources for the photocatalytic degradation of TCE and PCE, if operational conditions of N-$TiO_2$ photocatalytic system are optimized.