scholarly journals Development of a Hg-free UV light source and its performance in photolytic and photocatalytic applications

2019 ◽  
Vol 18 (2) ◽  
pp. 328-335 ◽  
Author(s):  
Satoshi Horikoshi ◽  
Daisuke Yamamoto ◽  
Kenta Hagiwara ◽  
Akihiro Tsuchida ◽  
Isamu Matsumoto ◽  
...  
Keyword(s):  
Light Source ◽  
Uv Light ◽  
Light Sources ◽  
Photocatalytic Applications

Constraints on light sources that use mercury (arc lamps) are evolving with the establishment of the Minamata Convention, which has led to the proliferation of LEDs.

scholarly journals Photopolymerization of dental materials: Types and characteristics of the light sources

2009 ◽  
Vol 56 (4) ◽  
pp. 207-212 ◽  
Author(s):  
Gorjana Popovic ◽  
Roze Djokic
Keyword(s):  
Absorption Spectrum ◽  
Light Source ◽  
Uv Light ◽  
Dental Materials ◽  
Life Time ◽  
Source Spectrum ◽  
Light Sources ◽  
Light Spectrum ◽  
Visible Part ◽  
Short Time

Light from the polymerization source which initiates photopolymerization in the material has its determined wavelength. Photoinitiator, such as camphorhinone, excited by light, can be activated with any of the wavelength from its absorption spectrum. To obtain successful photopolymerization, light source should emit waves of adequate wavelength; light intensity has to be optimal, to have sufficient time of exposure and material up to 2 mm thickness. Photoinitiator inside the material should match light source spectrum and work regime. Halogen lamps have wide spectra of wavelengths in the visible part of the light spectrum. Their spectra are similar to absorption spectrum of camphorhinone. Plasma (xenon) lamps emit blue light. Though their diapason is low, spectra have great intensity. Adequate diapason and easy excitation allow them to have short time of exposure. LED lamps have blue diodes as light source. They do not need filters due to narrow emission spectrum. Laser (argon) lamps are the only that emit linear spectra. Ultraviolet (mercury) lamps are not in use any more in dentistry; theirs initiators were activated by UV light. LED lamps have longer life time; do not change the spectra during time, warm less, do not need filters, allow change of the source for more powerful, more efficient and more advantageous two steps or impulse illumination mode. However, LED lamps can not be used for a material that has photoinitiator(s) activated by light with wavelength above the maximum of the LED spectra.

scholarly journals Performance Modeling of Ultraviolet Atmospheric Scattering of Different Light Sources Based on Monte Carlo Method

2020 ◽  
Vol 10 (10) ◽  
pp. 3564
Author(s):  
Qiushi Zhang ◽  
Xin Zhang ◽  
Lingjie Wang ◽  
Guangwei Shi ◽  
Qiang Fu ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Light Source ◽  
Ultraviolet Light ◽  
Transport Model ◽  
Uv Light ◽  
Probability Method ◽  
Light Sources ◽  
Atmospheric Transmission ◽  
Atmospheric Scattering ◽  
Near Ultraviolet

Since the atmosphere has a strong scattering effect on ultraviolet light, the transmission of non-line-of-sight (NLOS) signals can be realized in the atmosphere. In previous articles, ultraviolet (UV) light atmospheric scattering has been characterized by many scattering models based on spot light sources with uniformly distributed light intensity. In order to explore the role of light sources in atmospheric transmission, this work proposed a UV light atmospheric transport model under different types of light source, including light-emitting diode (LED), laser, and ordinary light sources, based on the Monte Carlo point probability method. The simulation of the light source in the proposed model is a departure from the use of a light source with uniform intensity distribution in previous articles. The atmospheric transmission efficiency of different light sources was calculated and compared with the data of existing models. The simulation results showed that the type of light source can significantly change the shape of the received signal and the received energy density. The Monte Carlo (MC) point probability method dramatically reduced the calculation time and the number of photons. The transmission characteristics of different ultraviolet light sources in the atmosphere provide a theoretical foundation for the design of ultraviolet detection and near-ultraviolet signal communication in the future.

Accessible, large-area, uniform dose photolithography using a moving light source

2021 ◽  
Author(s):  
Alexander Kaltashov ◽  
Prabu Karthick Parameshwar ◽  
Nicholas Lin ◽  
Christopher Moraes
Keyword(s):  
Light Source ◽  
Uv Light ◽  
Movement Pattern ◽  
Exposure Dose ◽  
Light Sources ◽  
Large Area ◽  
Domain Specific ◽  
Conventional Photolithography ◽  
Uv Lamp ◽  
Uv Dose

Abstract Photolithography is an essential microfabrication process in which ultraviolet (UV) light is projected through a mask to selectively expose and pattern a light-sensitive photoresist. Conventional photolithography devices are based on a stationary UV lamp and require carefully-designed optics to ensure that a uniform exposure dose is provided across the substrate being patterned. Access to such systems is typically limited to certain labs with domain-specific expertise and sufficient resources. The emergence of LED-based UV technologies has provided improved access to the necessary light sources, but issues with uniformity and limited exposure sizes still remain. In this work, we explore the use of a moving light source (MOLIS) for large-area lithography applications, in which the light source path speed, elevation, and movement pattern can be used to smooth out any spatial variations in source light intensity profiles, and deliver a defined and uniform cumulative UV exposure dose to a photoresist-coated substrate. By repurposing a 3D printer and UV-LED flashlight, we constructed an inexpensive MOLIS platform, simulated and verified the parameters needed to produce a uniform UV dose exposure, and demonstrate this approach for SU-8 microfabrication of features with dimensions relevant to many areas in biomedical engineering. The ready accessibility and inexpensive nature of this approach may be of considerable value to small laboratories interested in occasional and low-throughput prototype microfabrication applications.

Organic Light Emitting Diodes - Innovative Light Sources

2019 ◽  
pp. 101-107
Author(s):  
Sergei A. Stakharny
Keyword(s):  
Light Source ◽  
Organic Light Emitting Diodes ◽  
Organic Leds ◽  
Light Sources ◽  
High Quality ◽  
Light Emitting ◽  
Organic Light ◽  
Lighting Systems ◽  
Physical Principles ◽  
Prospects Of Application

This article is a review of the new light source – organic LEDs having prospects of application in general and special lighting systems. The article describes physical principles of operation of organic LEDs, their advantages and principal differences from conventional non-organic LEDs and other light sources. Also the article devoted to contemporary achievements and prospects of development of this field in the spheres of both general and museum lighting as well as other spheres where properties of organic LEDs as high-quality light sources may be extremely useful.

Development of a UV Light Source using Pr:LuAG Thin Film Target Pumped by Electron Beam

2015 ◽  
Vol 135 (9) ◽  
pp. 1049-1054
Author(s):  
Norio Ichikawa ◽  
Kohei Ikeda ◽  
Yoshinori Honda ◽  
Hiroyuki Taketomi ◽  
Koji Kawai ◽  
...  
Keyword(s):  
Thin Film ◽  
Electron Beam ◽  
Light Source ◽  
Uv Light

Immobilization of ZnO Suspension on Glass Substrate to Remove Filtration During the Removal of Remazol Red R from Aqueous Solution

2016 ◽  
Vol 12 (6) ◽  
pp. 4127-4133
Author(s):  
Nazmul Kayes ◽  
Jalil Miah ◽  
Md. Obaidullah ◽  
Akter Hossain ◽  
Mufazzal Hossain
Keyword(s):  
Aqueous Solution ◽  
Glass Substrate ◽  
Uv Light ◽  
Aqueous Suspension ◽  
Light Irradiation ◽  
Zno Films ◽  
Light Sources ◽  
Zno Film ◽  
Semiconductor Oxides ◽  
Remazol Red

Photodegradation of textile dyes in the presence of an aqueous suspension of semiconductor oxides has been of growing interest. Although this method of destruction of dyes is efficient, the main obstacle of applying this technique in the industry is the time and cost involving separation of oxides from an aqueous suspension. In this research, an attempted was made to develop ZnO films on a glass substrate by simple immobilization method for the adsorption and photodegradation of a typical dye, Remazol Red R (RRR) from aqueous solution. Adsorption and photodegradation of  RRR were performed in the presence of glass supported ZnO film. Photodegradation of the dye was carried out by varying different parameters such as the catalyst dosage, initial concentrations of RRR, and light sources. The percentage of adsorption as well as photodegradation increased with the amount of ZnO, reaches a maximum and then decreased. Maximum degradation has been found under solar light irradiation as compared to UV-light irradiation. Removal efficiency was also found to be influenced by the pre-sonication of ZnO suspension.

Green Synthesis of ZnO/Dy/NiO Heterostructures for Enhanced Photocatalytic Applications

2020 ◽  
Vol 1 (1) ◽  
pp. 30-36
Author(s):  
Shubha Jayachamarajapura Pranesh ◽  
Diwya Lanka
Keyword(s):  
Visible Light ◽  
Uv Light ◽  
Combustion Method ◽  
Hybrid Nanocomposites ◽  
Synthetic Dyes ◽  
Hybrid Nanostructure ◽  
Wide Range ◽  
Visible Light Active ◽  
Textile Industries ◽  
Photocatalytic Applications

Background: Textile industries discharge harmful synthetic dyes to nearby water sources. These colour effluents should be treated before discharge to reduce the toxicity caused by synthetic colours. Objective: To synthesize visible light active superstructures to reduce water pollution caused by textile industries. Methods: We have successfully synthesized ZnO/Dy/NiO hybrid nanocomposites using waste curd as fuel by a simple combustion method. The obtained material was able to reduce recombination and enhanced the photocatalytic degradation of organic pollutants. The as-synthesized material was characterized by XRD, absorption spectroscopy, FESEM, EDAX, etc. The obtained hybrid nanostructure was used as a photocatalyst for the degradation of methylene blue under sunlight, UV light as well as in dark. Comparative experiments were carried out with a variation of catalytic load, pH, dye concentrations, etc. for a better understanding of the performance of the catalyst at various conditions. Results and Conclusion: The ternary compound shows wide range of absorption by expanding absorption band both in UV and visible regions. ZnO/Dy/NiO hybrid nanocomposites performed well and showed uniqueness in the activity uder visible light.

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

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