ACCURATE MEASUREMENT OF ULTRAVIOLET LIGHT-EMITTING DIODES

2021 ◽  
Author(s):  
C. Yuqin Zong ◽  
Cameron Miller
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Luminous Flux ◽  
Junction Temperature ◽  
Integrating Sphere ◽  
Light Emitting ◽  
Type D ◽  
Uv Led ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

We have developed a new calibration capability for 200 nm to 400 nm ultraviolet light-emitting diodes (UV LEDs) using a Type D gonio-spectroradiometer. The recently-introduced mean differential continuous pulse (M-DCP) method is used to overcome the measurement difficulty associated with the initial forward voltage, VF, anomaly of a UV LED, which makes it impossible to use VF to infer junction temperature, TJ, during pulsed operation. The new measurement facility was validated indirectly by comparing the measured total luminous flux of a white LED with that measured using the NIST’s 2.5 m absolute integrating sphere. The expanded calibration uncertainty for the total radiant flux is approximately 2 % to 3 % (k = 2) depending the wavelength of the UV LED.

Progress and Perspective of Near-Ultraviolet and Deep-Ultraviolet Light-Emitting Diode Packaging Technologies

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Yang Peng ◽  
Renli Liang ◽  
Yun Mou ◽  
Jiangnan Dai ◽  
Mingxiang Chen ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Near Ultraviolet ◽  
Uv Led ◽  
Duv Led ◽  
Deep Ultraviolet ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Light Efficiency

Abstract Ultraviolet light-emitting diodes (UV-LEDs) have drawn considerable attention in environment, life science, and industry fields, such as the applications of near UV-LEDs in resin curing, illumination, and identification, and deep UV-LEDs in disinfection, medical treatment, and biochemical inspection. However, due to the limitation of packaging technology, UV-LED devices exhibit low light efficiency and poor reliability compared with visible LEDs. The organic encapsulation materials are prone to UV aging, thermal degradation, and nonairtightness, which significantly reduce the performances of UV-LEDs. In order to solve this issue, UV-LED packaging technology has been proposed for UV-LED devices instead of conventional LED packaging. In this review, we investigated in detail the overview and challenges of near-ultraviolet light-emitting diodes (NUV-LED)/deep-ultraviolet light-emitting diodes (DUV-LED) packaging. For the packaging of UV-LEDs, all inorganic encapsulation materials, hermetic packaging structures with low-temperature bonding, reduced reflection losses, UV stable and transparent materials, and effective thermal management are key progresses to enhance the light efficiency and reliability of UV-LEDs. In addition, the summary and perspectives of NUV-LED/DUV-LED packaging were introduced and discussed.

scholarly journals Irradiation by a Combination of Different Peak-Wavelength Ultraviolet-Light Emitting Diodes Enhances the Inactivation of Influenza A Viruses

2020 ◽  
Vol 8 (7) ◽  
pp. 1014
Author(s):  
Mizuki Kojima ◽  
Kazuaki Mawatari ◽  
Takahiro Emoto ◽  
Risa Nishisaka-Nonaka ◽  
Thi Kim Ngan Bui ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Influenza A ◽  
Light Emitting Diodes ◽  
Strongly Correlated ◽  
Influenza A Viruses ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Lamp ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

Influenza A viruses (IAVs) pose a serious global threat to humans and their livestock. This study aimed to determine the ideal irradiation by ultraviolet-light emitting diodes (UV-LEDs) for IAV disinfection. We irradiated the IAV H1N1 subtype with 4.8 mJ/cm2 UV using eight UV-LEDs [peak wavelengths (WL) = 365, 310, 300, 290, 280, 270, and 260 nm)] or a mercury low pressure (LP)-UV lamp (Peak WL = 254 nm). Inactivation was evaluated by the infection ratio of Madin–Darby canine kidney (MDCK) cells or chicken embryonated eggs. Irradiation by the 260 nm UV-LED showed the highest inactivation among all treatments. Because the irradiation-induced inactivation effects strongly correlated with damage to viral RNA, we calculated the correlation coefficient (RAE) between the irradiant spectrum and absorption of viral RNA. The RAE scores strongly correlated with the inactivation by the UV-LEDs and LP-UV lamp. To increase the RAE score, we combined three different peak WL UV-LEDs (hybrid UV-LED). The hybrid UV-LED (RAE = 86.3) significantly inactivated both H1N1 and H6N2 subtypes to a greater extent than 260 nm (RAE = 68.6) or 270 nm (RAE = 42.2) UV-LEDs. The RAE score is an important factor for increasing the virucidal effects of UV-LED irradiation.

scholarly journals 310 nm UV-LEDs attenuate imiquimod-induced psoriasis-like skin lesions in C57BL/6 mice and inhibit IL-22-induced STAT3 expression in HaCaT cells

2020 ◽  
Vol 19 (8) ◽  
pp. 1009-1021
Author(s):  
Tae-Rin Kwon ◽  
Sung-Eun Lee ◽  
Jong Hwan Kim ◽  
You Na Jang ◽  
Su-Young Kim ◽  
...  
Keyword(s):  
Light Source ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Skin Lesions ◽  
Hacat Cells ◽  
Light Emitting ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes

Ultraviolet light-emitting diodes (UV-LEDs) are a novel light source for phototherapy.

Development of an Al2O3 filled composite for the bracket of ultraviolet light-emitting diodes (UV-LEDs)

2018 ◽  
Vol 83 ◽  
pp. 356-362 ◽  
Author(s):  
Lei Zhang ◽  
Yiting Zheng ◽  
Jiale Mao ◽  
Shuang Wang ◽  
Ruotian Fu ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Light Emitting ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Filled Composite

Junction Temperature in Ultraviolet Light-Emitting Diodes

2005 ◽  
Vol 44 (10) ◽  
pp. 7260-7266 ◽  
Author(s):  
Yangang Xi ◽  
Thomas Gessmann ◽  
Jingqun Xi ◽  
Jong Kyu Kim ◽  
Jay M. Shah ◽  
...  
Keyword(s):  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Junction Temperature ◽  
Light Emitting ◽  
Ultraviolet Light Emitting Diodes

scholarly journals Comparison of ultraviolet light emitting diodes with traditional UV for greywater disinfection

2014 ◽  
Vol 5 (1) ◽  
pp. 17-27 ◽  
Author(s):  
M. J. Crook ◽  
B. Jefferson ◽  
O. Autin ◽  
J. MacAdam ◽  
A. Nocker
Keyword(s):  
Particle Size ◽  
Ultraviolet Light ◽  
Water Reuse ◽  
Light Emitting Diodes ◽  
Microbial Inactivation ◽  
Small Scale ◽  
Light Emitting ◽  
Uv Leds ◽  
The Impact ◽  
Ultraviolet Light Emitting Diodes

The current technological status of ultraviolet light emitting diodes (UV-LEDs) has reached a point where small-scale ultraviolet (UV) water disinfection applications, that is, for greywater reuse appear increasingly promising. This study compares the germicidal and economical aspects of UV-LEDs with traditional UV. Pure cultures and environmental greywater samples were exposed to different radiation doses from both UV sources with the germicidal effect comparative at equivalent doses. The impact of particle size on disinfection efficiency was investigated in two greywater fractions of varying mean particle size. Disinfection efficiency was found to be dependent on particle size with larger particles reducing microbial inactivation for both UV sources. Post-UV blending to detach particle-associated coliforms resulted in higher bacterial counts for both UV sources although to a lesser extent for UV-LEDs suggesting that it might be less affected by the presence of particles than traditional UV sources, possibly due to the UV radiation being emitted by multiple diodes at different angles compared to the traditional UV collimated beam setup. Nevertheless, removal of particles prior to UV disinfection is necessary to meet strict water reuse standards. Although UV-LEDs are currently prohibitively expensive, improvements in performance indicators might make this technology economically competitive within the next few years.

Ultraviolet light emitting diodes using non-polar A-plane AlGaN multiple quantum wells

2006 ◽  
Vol 955 ◽  
Author(s):  
Ramya Chandrasekaran ◽  
Anirban Bhattacharyya ◽  
Ryan France ◽  
Christos Thomidis ◽  
Adrian Williams ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Ultraviolet Light ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Multiple Quantum ◽  
Light Emitting ◽  
Current Voltage ◽  
Uv Leds ◽  
Ultraviolet Light Emitting Diodes ◽  
Electro Luminescence

ABSTRACTIn this paper, we report the growth and fabrication of non-polar A-plane AlGaN multiple quantum well based ultraviolet light emitting diodes (UV-LEDs). The LEDs were grown on R-plane sapphire substrates using molecular beam epitaxy (MBE). The Current-voltage characteristics of the fabricated devices demonstrated rectifying behavior with a series resistance of 38 ohms. An electro-luminescence emission at 338 nm was obtained.

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