scholarly journals Double-Sided Freeform Lens for Light Collimation of Light Emitting Diodes

2019 ◽  
Vol 9 (24) ◽  
pp. 5452
Author(s):  
Yong-Sin Syu ◽  
Chun-Ying Wu ◽  
Yung-Chun Lee
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Design Parameters ◽  
Injection Molding Process ◽  
Light Sources ◽  
Molding Process ◽  
Light Emitting ◽  
Uv Led ◽  
Simulation Results ◽  
Freeform Lens

A double-sided freeform lens is proposed for collimating light emitted from light emitting diodes (LEDs). The surface profiles of the lens are mathematically characterized and precisely determined based on a point-source assumption and differential geometry theory. The proposed lens design method is straightforward, flexible, and effective. Moreover, the optical performance of the lens can be intuitively adjusted by tuning just a small number of design parameters. The simulation results showed that the proposed lens achieved an excellent collimating effect for a commercial ultraviolet (UV) LED. A prototype lens is fabricated in UV-grade poly(methyl methacrylate) material using a standard injection molding process. The light collimating effect of the lens/UV-LED assembly was measured experimentally and was shown to be in good agreement with the simulation results. The collimating angle at the half-energy level was equal to 1.88°. The performance of the UV-LED is thus comparable to that of conventional lithography UV light sources based on mercury arc lamps. Consequently, the proposed double freeform lens showed significant potential for photolithography applications within the industry.

Performance of the light emitting diodes versus conventional light sources in the UV light cured formulations

2007 ◽  
Vol 105 (2) ◽  
pp. 803-808 ◽  
Author(s):  
Kelechi C. Anyaogu ◽  
Andrey A. Ermoshkin ◽  
Douglas C. Neckers ◽  
Alex Mejiritski ◽  
Oleg Grinevich ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Light Sources ◽  
Light Emitting

scholarly journals Study of Exposure Uniformity of UV LED Exposure System for Wafer-Level Camera Lenses

2019 ◽  
Vol 9 (19) ◽  
pp. 4110 ◽  
Author(s):  
Kuo-Tsai Wu ◽  
Sheng-Jye Hwang ◽  
Huei-Huang Lee
Keyword(s):  
Experimental Data ◽  
Uv Light ◽  
Optical Simulation ◽  
Curing Process ◽  
Wafer Level ◽  
Exposure System ◽  
Light Emitting ◽  
Uv Led ◽  
Simulation Results ◽  
Standard Range

Wafer-level camera lenses are a very promising process for camera lens fabrication. However, there exist some problems with this technology, such as uneven exposure due to curing non-uniformities. In this study, an optical simulation was implemented to simulate the UV light-emitting diodes (LEDs) curing process. We design the LED arrangement, and then find the corresponding LED and adjust the LED power to improve exposure uniformity. The simulation results are very close to the experimental data, and the uniformity is also within the standard range.

scholarly journals Estimation of the Ultraviolet-C Doses from Mercury Lamps and Light-Emitting Diodes Required to Disinfect Surfaces

2021 ◽  
Vol 126 ◽  
Author(s):  
Pablo Fredes ◽  
Ulrich Raff ◽  
Ernesto Gramsch ◽  
Marcelo Tarkowski
Keyword(s):  
Light Emitting Diodes ◽  
Optical Power ◽  
Computational Procedure ◽  
Light Sources ◽  
Dose Distributions ◽  
Light Emitting ◽  
Radiant Efficiency ◽  
Ultraviolet C ◽  
Simulation Results ◽  
Uv C

Disinfection of surfaces by ultraviolet-C (UV-C) radiation is gaining importance in diverse applications. However, there is generally no accepted computational procedure to determine the minimum irradiation times and UV-C doses required for reliable and secure disinfection of surfaces. UV-C dose distributions must be comparable for devices presently on the market and future ones, as well as for the diverse surfaces of objects to be disinfected. A mathematical model is presented to estimate irradiance distributions. To this end, the relevant parameters are defined. These parameters are the optical properties of the UV-C light sources, such as wavelength and emitted optical power, as well as electrical features, like radiant efficiency and consumed power. Furthermore, the characteristics and geometry of the irradiated surfaces as well as the positions of the irradiated surfaces in relation to the UV-C light sources are considered. Because mercury (Hg) lamps are competitive with UV-C light-emitting diodes, a comparative analysis between these two light sources based on the simulation results is also discussed.

Inactivation of health-related microorganisms in water using UV light-emitting diodes

2019 ◽  
Vol 19 (5) ◽  
pp. 1507-1514 ◽  
Author(s):  
Kumiko Oguma ◽  
Surapong Rattanakul ◽  
Mie Masaike
Keyword(s):  
Spectral Sensitivity ◽  
Legionella Pneumophila ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Feline Calicivirus ◽  
Response Curves ◽  
K Value ◽  
Light Emitting ◽  
Uv Led ◽  
Uv Leds

Abstract UV light-emitting diodes (UV-LEDs) offer various wavelength options, while microorganisms have spectral sensitivity, or so-called action spectra, which can be different among species. Accordingly, matching properly the emission spectra of UV-LEDs and the spectral sensitivity of microorganisms is a reasonable strategy to enhance inactivation. In this study, UV-LEDs with nominal peak emissions at 265, 280 and 300 nm were applied to pathogens including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio parahaemolyticus and feline calicivirus, in comparison with indicator species including Escherichia coli, Bacillus subtilis spores, bacteriophage Qβ and MS2. The results indicated that, for all species tested, 265 nm UV-LED was highest in the fluence-based inactivation rate constant k, followed by 280 nm and 300 nm was much lower. The k value at 280 nm was close to that at 265 nm for feline calicivirus and MS2, suggesting that 280 nm UV-LED can be as good an option as 265 nm UV-LED to inactivate these viruses. Bacteria tended to show fluence-response curves with shoulder and tailing, while viruses followed log-linear profiles at all wavelengths tested. This study indicates the fluence-response profiles and the fluence required for a target inactivation of microorganisms, which would serve as reference data for future study and applications of UV-LEDs.

scholarly journals Using UVC Light-Emitting Diodes at Wavelengths of 266 to 279 Nanometers To Inactivate Foodborne Pathogens and Pasteurize Sliced Cheese

2015 ◽  
Vol 82 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Soo-Ji Kim ◽  
Do-Kyun Kim ◽  
Dong-Hyun Kang
Keyword(s):  
Foodborne Pathogens ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Content Type ◽  
Warm Up ◽  
Light Emitting ◽  
Uv Led ◽  
Serovar Typhimurium ◽  
Uv Lamps ◽  
Uv Leds

ABSTRACTUVC light is a widely used sterilization technology. However, UV lamps have several limitations, including low activity at refrigeration temperatures, a long warm-up time, and risk of mercury exposure. UV-type lamps only emit light at 254 nm, so as an alternative, UV light-emitting diodes (UV-LEDs) which can produce the desired wavelengths have been developed. In this study, we validated the inactivation efficacy of UV-LEDs by wavelength and compared the results to those of conventional UV lamps. Selective media inoculated withEscherichia coliO157:H7,Salmonella entericaserovar Typhimurium, andListeria monocytogeneswere irradiated using UV-LEDs at 266, 270, 275, and 279 nm in the UVC spectrum at 0.1, 0.2, 0.5, and 0.7 mJ/cm2, respectively. The radiation intensity of the UV-LEDs was about 4 μW/cm2, and UV lamps were covered with polypropylene films to adjust the light intensity similar to those of UV-LEDs. In addition, we applied UV-LED to sliced cheese at doses of 1, 2, and 3 mJ/cm2. Our results showed that inactivation rates after UV-LED treatment were significantly different (P< 0.05) from those of UV lamps at a similar intensity. On microbiological media, UV-LED treatments at 266 and 270 nm showed significantly different (P< 0.05) inactivation effects than other wavelength modules. For sliced cheeses, 4- to 5-log reductions occurred after treatment at 3 mJ/cm2for all three pathogens, with negligible generation of injured cells.

scholarly journals Design of a Secondary Freeform Lens of UV LED Mosquito-Trapping Lamp for Enhancing Trapping Efficiency

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 335 ◽  
Author(s):  
Wei-Hsiung Tseng ◽  
Diana Juan ◽  
Wei-Cheng Hsiao ◽  
Cheng-Han Chan ◽  
Hsin-Yi Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Intensity Distribution ◽  
Light Emitting Diode ◽  
Trapping Efficiency ◽  
Axially Symmetric ◽  
Light Intensity Distribution ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Freeform Lens

In this study, our proposed ultraviolet light-emitting diode (UV LED) mosquito-trapping lamp is designed to control diseases brought by insects such as mosquitoes. In order to enable the device to efficiently catch mosquitoes in a wider area, a secondary freeform lens (SFL) is designed for UV LED. The lens is mounted on a 3 W UV LED light bar as a mosquito-trapping lamp of the new UV LED light bar module to achieve axially symmetric light intensity distribution. The special SFL is used to enhance the trapping capabilities of the mosquito-trapping lamp. The results show that when the secondary freeform surface lens is applied to the experimental outdoor UV LED mosquito-trapping lamp, the trapping range can be expanded to 100π·m2 and the captured mosquitoes increased by about 300%.

Performance of vertical type deep UV light-emitting diodes depending on the Ga-face n-contact hole density

2021 ◽  
Vol 118 (23) ◽  
pp. 231102
Author(s):  
Youn Joon Sung ◽  
Dong-Woo Kim ◽  
Geun Young Yeom ◽  
Kyu Sang Kim
Keyword(s):  
Light Emitting Diodes ◽  
Uv Light ◽  
Hole Density ◽  
Light Emitting ◽  
Deep Uv

New Results on Electroluminescence from Porous Silicon

1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang
Keyword(s):  
Porous Silicon ◽  
Quantum Efficiency ◽  
Light Emitting Diodes ◽  
Uv Light ◽  
Green Light ◽  
Light Emitting ◽  
Porous Region ◽  
First Results

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.

scholarly journals Application of Light-Emitting Diodes for Improving the Nutritional Quality and Bioactive Compound Levels of Some Crops and Medicinal Plants

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1477
Author(s):  
Woo-Suk Jung ◽  
Ill-Min Chung ◽  
Myeong Ha Hwang ◽  
Seung-Hyun Kim ◽  
Chang Yeon Yu ◽  
...  
Keyword(s):  
Plant Growth ◽  
In Vitro Culture ◽  
Light Emitting Diodes ◽  
Photosynthetic Pigment ◽  
Antioxidant Properties ◽  
Light Sources ◽  
Light Emitting ◽  
Cell Defense ◽  
Led Irradiation

Light is a key factor that affects phytochemical synthesis and accumulation in plants. Due to limitations of the environment or cultivated land, there is an urgent need to develop indoor cultivation systems to obtain higher yields with increased phytochemical concentrations using convenient light sources. Light-emitting diodes (LEDs) have several advantages, including consumption of lesser power, longer half-life, higher efficacy, and wider variation in the spectral wavelength than traditional light sources; therefore, these devices are preferred for in vitro culture and indoor plant growth. Moreover, LED irradiation of seedlings enhances plant biomass, nutrient and secondary metabolite levels, and antioxidant properties. Specifically, red and blue LED irradiation exerts strong effects on photosynthesis, stomatal functioning, phototropism, photomorphogenesis, and photosynthetic pigment levels. Additionally, ex vitro plantlet development and acclimatization can be enhanced by regulating the spectral properties of LEDs. Applying an appropriate LED spectral wavelength significantly increases antioxidant enzyme activity in plants, thereby enhancing the cell defense system and providing protection from oxidative damage. Since different plant species respond differently to lighting in the cultivation environment, it is necessary to evaluate specific wavebands before large-scale LED application for controlled in vitro plant growth. This review focuses on the most recent advances and applications of LEDs for in vitro culture organogenesis. The mechanisms underlying the production of different phytochemicals, including phenolics, flavonoids, carotenoids, anthocyanins, and antioxidant enzymes, have also been discussed.

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