Journal articles: 'Electrical device-LED'

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Dal Lago, M., M. Meneghini, N. Trivellin, G. Mura, M. Vanzi, G. Meneghesso, and E. Zanoni. "“Hot-plugging” of LED modules: Electrical characterization and device degradation." Microelectronics Reliability 53, no. 9-11 (September 2013): 1524–28. http://dx.doi.org/10.1016/j.microrel.2013.07.054.

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Liu, H. C., E. Dupont, M. Byloos, M. Buchanan, C. Y. Song, and Z. R. Wasilewski. "QWIP-LED PIXELLESS THERMAL IMAGING DEVICE." International Journal of High Speed Electronics and Systems 12, no. 03 (September 2002): 891–905. http://dx.doi.org/10.1142/s0129156402001733.

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Over the past several years, we have been developing an alternative approach to thermal imaging based on pixelless quantum well infrared photodetectors (QWIP) integrated with light emitting diodes (LED). This paper reviews the basic concept, presents our latest results, and discusses issues related to the imaging performance. Analytical expressions are derived for evaluating noise equivalent temperature difference. Areas that need improvements are pointed out.

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Zhao, Zhan Feng, and Juan Ye. "Design Key Points for High Power LED Encapsulation." Advanced Materials Research 651 (January 2013): 706–9. http://dx.doi.org/10.4028/www.scientific.net/amr.651.706.

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LED performance was significantly improved because of the improvement of encapsulation design and materials properties. The design key points were reviewed in point view of optical, electrical, thermal, and reliability consideration. It was concluded that the packaging design should be simultaneously implemented with the chip design, integrally considering the optics, electrics, thermal, and reliability together. The interfacial thermal resistance and stress from packaging also play critical roles for the optical efficiency and reliability of packaged LED device.

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Arakawa, Takumi, and Kazuya Tada. "Improvement of Simple Spectral Sensitivity Measurement Device Using LED." IEEJ Transactions on Electronics, Information and Systems 139, no. 12 (December 1, 2019): 1527–28. http://dx.doi.org/10.1541/ieejeiss.139.1527.

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PRALGAUSKAITĖ, SANDRA, VILIUS PALENSKIS, JONAS MATUKAS, JUOZAS PETRULIS, and GENADIJUS KURILČIK. "NOISE CHARACTERISTICS AND RELIABILITY OF LIGHT EMITTING DIODES BASED ON NITRIDES." Fluctuation and Noise Letters 07, no. 03 (September 2007): L367—L378. http://dx.doi.org/10.1142/s0219477507004008.

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Optical and electrical noises and correlation factor between optical and electrical fluctuations of nitride-based light emitting diodes (LEDs) have been investigated under forward bias. Their electrical, optical and noise characteristics were compared with ones of LEDs of other materials. LED noise characteristic changes during aging have been measured, too. It is found that optical and electrical noise spectra under forward bias for more reliable LEDs distinguish by lower l/f type fluctuations and Lorentzian type noise at higher frequencies. LEDs with intensive 1/f noise demonstrate shorter lifetime. It is shown that reason of LED degradation is related with defects presence in device structure. These defects can be formed during device fabrication or appear during operation. An analysis of LED current-voltage and electrical noise characteristics under forward and reverse bias has shown that LEDs with intensive 1/f electrical noise, large reverse current (low reverse breakdown voltage) and larger terminal voltage under forward bias distinguish by short lifetime.

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Mamaev, Daniil S., and Artem A. Sharapov. "DEVELOPMENT OF A SMART LED LIGHT LAMP." Interexpo GEO-Siberia 7, no. 1 (July 8, 2020): 181–86. http://dx.doi.org/10.33764/2618-981x-2020-7-1-181-186.

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The article presents the process of developing a smart LED lamp. This device acts as a weather station, a security system and an ergonomic small lamp. The smart LED lamp can be used by ordinary citizens, gardeners or companies. By connecting the lamp to the Internet, it is possible to view information about the environment and the status of the security system from anywhere in the world. The electrical circuit of the device, a simulated 3D model of the case, assembled prototype, mobile application are given. The basic details necessary for the functioning of this device are determined. The result of the operation of the device is shown.

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Chen, Hsiang, Kun Min Hsieh, Yun Yang He, Li Chen Chu, Ming Ling Lee, and Kow Ming Chang. "Degradation of InGaN/GaN LEDs under Forward-bias Operations in Salty Water Vapor." Journal of New Materials for Electrochemical Systems 19, no. 1 (February 15, 2016): 007–10. http://dx.doi.org/10.14447/jnmes.v19i1.340.

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Forward-bias stress in salty water vapor can quickly degrade the InGaN/GaN LEDs. To examine the weakness of the device, electrical, optical, and material analyses and characterizations were performed to investigate the failure mechanism. Corrosion of the electrode and Au atom diffusion might result in damages of the device. Results indicate that forward-bias stress in salty water vapor can quickly influence the material properties, optical behaviors, and electrical characteristics of the LED device.

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SMOLIANINOV, V., and A. SUKHOPARA. "Improving the operation of the linear electromagnetic step device." Journal of Electrical and power engineering 23, no. 2 (December 23, 2020): 38–43. http://dx.doi.org/10.31474/2074-2630-2020-2-38-43.

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The improved operation of the linear electromagnetic device (LED) is proposed, without the use of additional sensors for control motion of mobile link LED and automation of technological process. Research focused on determination of the relationship of changes in active inductive parameters of the LED with its design parameters when moving the mobile link of LED and construction an improving the operation, that controls these changes for the increasing the efficiency of their functioning. For this research a theories of electrical circuits and electronic circuits were implemented, which takes into account the change in electrical parameters when moving the mobile link of the linear electromagnetic device. It is proved the dependence of the magnetic resistance in certain sections of the magnetic circuit from the position the mobile link and the design parameters of the LED, the intervals of the magnetic resistance change when the mobile link is moved by the size of the step. The accordance is found between the change in active - inductive parameters when the position of the moving link

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Zheng, Fuzhong, Shaochun Huang, Yuan Zhai, Yi Xiang, and Ying Wu. "LED Device Based on Single-Walled Carbon Nanotube Arrays." Journal of Nanoelectronics and Optoelectronics 16, no. 3 (March 1, 2021): 368–73. http://dx.doi.org/10.1166/jno.2021.2963.

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The migration model of the (n, 0) zigzag SWNT is established on the basis of Mathiessen’s law to calculate carrier mobility, which are the foundation for performance analysis of electroluminescence light emission. The split-gate technique is used to create p-and n-doped regions in the single-walled carbon nanotube (SWNT) arrays that are separated by a gap with a width of several microns. The LED devices based on SWNT arrays using split-gate technique are fabricated and tested by using an optical measurement system. Compared to the LED with the central gate, the split-gate SWNT LED has enhanced the light generation efficiency of the intrinsic SWNT array segment by decreasing the potential barrier across the junction of the intrinsic SWNT array segment. The results demonstrate the luminescent principle of LED based on SWNT array in theoretical simulation and device measurement.

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Rashid, Muhammad Haroon, Ants Koel, Toomas Rang, Nadeem Nasir, Haris Mehmood, and Salman Cheema. "Modeling and Simulations of 4H-SiC/6H-SiC/4H-SiC Single Quantum-Well Light Emitting Diode Using Diffusion Bonding Technique." Micromachines 12, no. 12 (November 30, 2021): 1499. http://dx.doi.org/10.3390/mi12121499.

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In the last decade, silicon carbide (SiC) has emerged as a potential material for high-frequency electronics and optoelectronics applications that may require elevated temperature processing. SiC exists in more than 200 different crystallographic forms, referred to as polytypes. Based on their remarkable physical and electrical characteristics, such as better thermal and electrical conductivities, 3C-SiC, 4H-SiC, and 6H-SiC are considered as the most distinguished polytypes of SiC. In this article, physical device simulation of a light-emitting diode (LED) based on the unique structural configuration of 4H-SiC and 6H-SiC layers has been performed which corresponds to a novel material joining technique, called diffusion welding/bonding. The proposed single quantum well (SQW) edge-emitting SiC-based LED has been simulated using a commercially available semiconductor device simulator, SILVACO TCAD. Moreover, by varying different design parameters, the current-voltage characteristics, luminous power, and power spectral density have been calculated. Our proposed LED device exhibited promising results in terms of luminous power efficiency and external quantum efficiency (EQE). The device numerically achieved a luminous efficiency of 25% and EQE of 16.43%, which is at par performance for a SQW LED. The resultant LED structure can be customized by choosing appropriate materials of varying bandgaps to extract the light emission spectrum in the desired wavelength range. It is anticipated that the physical fabrication of our proposed LED by direct bonding of SiC-SiC wafers will pave the way for the future development of efficient and cost-effective SiC-based LEDs.

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Zhang, Guangjun, Min Yuan, and Zheng Wang. "Design of Photovoltaic Panel-Light-Emitting Diode Spotlight and Its Performance Analysis in Tunnel Buildings." Journal of Nanoelectronics and Optoelectronics 16, no. 7 (July 1, 2021): 1067–74. http://dx.doi.org/10.1166/jno.2021.3076.

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According to the adaptive characteristics of the entrance and exit sections of tunnel buildings with the intensity of external sunlight, the cost of traditional photovoltaic panel (PV)-light-emitting diode (LED) lighting system increases due to battery. Combined with the structure of sunshine conveyor, a new PV-LED spotlight is proposed. The lighting device uses PV module as the power supply to directly drive the LED light source, which can make the brightness of the tunnel synchronized with the sunlight intensity, avoid the problem that it cannot work stably due to its weather changes, and further save the cost without battery. The main control chip adopts STC12C5A60S2 and supports multiple 10-bits precision A/D conversion channels. It can process the output signal of the light intensity detection circuit and set a threshold circuit to judge the intensity of sunlight, further control the working state of LED lighting device. The LED display module adopts 12864 liquid crystal display (LCD) with built-in T6963C driver to display five kinds of data, including the output voltage of light intensity detection circuit and the corresponding voltage value of four threshold circuits. The circuit resistance can be adjusted to change the light output voltage threshold required by the tunnel. In the test, the PV-LED lighting device is erected in the tunnel building. Compared with the traditional PV-LED lighting device and the new PV-LED spotlight designed, the new PV-LED lighting device in the morning and evening can further improve the efficiency of solar power generation. Meanwhile, the PV plate plane of the designed lighting device is perpendicular to the plane where the sunlight shines. The spectral irradiance and full band spectral irradiance of the lighting device in six bands was calculated and found that the percentage of spectral irradiance in different bands is close to the percentage requirement under AM1.5.

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Zhang, Guangjun, Min Yuan, and Zheng Wang. "Design of Photovoltaic Panel-Light-Emitting Diode Spotlight and Its Performance Analysis in Tunnel Buildings." Journal of Nanoelectronics and Optoelectronics 16, no. 7 (July 1, 2021): 1067–74. http://dx.doi.org/10.1166/jno.2021.3076.

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According to the adaptive characteristics of the entrance and exit sections of tunnel buildings with the intensity of external sunlight, the cost of traditional photovoltaic panel (PV)-light-emitting diode (LED) lighting system increases due to battery. Combined with the structure of sunshine conveyor, a new PV-LED spotlight is proposed. The lighting device uses PV module as the power supply to directly drive the LED light source, which can make the brightness of the tunnel synchronized with the sunlight intensity, avoid the problem that it cannot work stably due to its weather changes, and further save the cost without battery. The main control chip adopts STC12C5A60S2 and supports multiple 10-bits precision A/D conversion channels. It can process the output signal of the light intensity detection circuit and set a threshold circuit to judge the intensity of sunlight, further control the working state of LED lighting device. The LED display module adopts 12864 liquid crystal display (LCD) with built-in T6963C driver to display five kinds of data, including the output voltage of light intensity detection circuit and the corresponding voltage value of four threshold circuits. The circuit resistance can be adjusted to change the light output voltage threshold required by the tunnel. In the test, the PV-LED lighting device is erected in the tunnel building. Compared with the traditional PV-LED lighting device and the new PV-LED spotlight designed, the new PV-LED lighting device in the morning and evening can further improve the efficiency of solar power generation. Meanwhile, the PV plate plane of the designed lighting device is perpendicular to the plane where the sunlight shines. The spectral irradiance and full band spectral irradiance of the lighting device in six bands was calculated and found that the percentage of spectral irradiance in different bands is close to the percentage requirement under AM1.5.

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Zongtao Li, Zongtao Li, Huiyu Wang Huiyu Wang, Binhai Yu Binhai Yu, Xinrui Ding Xinrui Ding, and and Yong Tang and Yong Tang. "High-efficiency LED COB device combined diced V-shaped pattern and remote phosphor." Chinese Optics Letters 15, no. 4 (2017): 042301–42304. http://dx.doi.org/10.3788/col201715.042301.

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Nesterkina, Nina P., Olga Yu Kovalenko, Yulia A. Zhuravlyova, Ilya A. Oleynik, and Svetlana A. Shegurenkova. "Research of the Characteristics of a Modular Luminaire with LEDs for Outdoor Lighting." Light & Engineering, no. 05-2022 (October 2022): 98–105. http://dx.doi.org/10.33383/2022-022.

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This article presents the results of the study of electrical, light, and spectral characteristics of the Lisma Module M1 MK‑3 81W outdoor LED modular luminaire. The measurement results were compared with the values of the characteristics declared by the manufacturer in order to identify the accuracy of the declared rated parameters. The studies demonstrated that luminous flux, luminous efficacy, and power capacity of the device are virtually identical to the values declared by the manufacturer (within the tolerance limits). The luminaire has good colour rendering and rather soft radiation spectrum with chromaticity corresponding to neutral white light. The structure of the studied LED device is described. The studied luminaire is compared to other LED lighting devices manufactured in Russia. The recommendations regarding application of the studied LED luminaire are provided.

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Kim, Yong-Kab, Hyoung Jin Kim, Byoung Chol Kim, and Byeong Seon Park. "Implementation of Electrical and Optical characteristicsbased on new packaging in UV LED." Korean Institute of Smart Media 11, no. 9 (October 31, 2022): 21–29. http://dx.doi.org/10.30693/smj.2022.11.9.21.

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Ultra Violet(UV) is gradually being replaced with LED instead of general UV lamps. However, the light efficiency of UV LED is still lower than that of the general lamp, and the light efficiency is also low. Due to the current environment and technical problems of UV lamps, the LED replacements are gradually being made. In this study, a new package design and analysis were performed to increase the lifetime and performance of UV LEDs. A new packaging for UV LED were designed and implemented. The new packaging for UV LED was constructed to improve light efficiency. And the electrical and optical characteristics were analyzed respectively. To improve the optical efficiency in UV LED package, the Al has been used based on high reflectivity and applying the optimal lens focusing. Compared to the existing silver Ag, the light efficiency was improved by about 30% or more, and it was confirmed that the light output degradation characteristic was improved by about 10% in the newly applied optical device chip.

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Legendre, J., and P. O. Chapuis. "Overcoming non-radiative losses with AlGaAs PIN junctions for near-field thermophotonic energy harvesting." Applied Physics Letters 121, no. 19 (November 7, 2022): 193902. http://dx.doi.org/10.1063/5.0116662.

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In a thermophotonic device used in an energy-harvesting configuration, a hot light-emitting diode (LED) is coupled to a photovoltaic (PV) cell by means of electroluminescent radiation in order to produce electrical power. Using fluctuational electrodynamics and the drift-diffusion equations, we optimize a device made of an AlGaAs PIN LED and a GaAs PIN PV cell with matched bandgaps. We find that the LED can work as an efficient heat pump only in the near field, where radiative heat transfer is increased by wave tunneling. A key reason is that non-radiative recombination rates are reduced compared to radiative ones in this regime. At 10 nm gap distance and for [Formula: see text] effective surface recombination velocity, the power output can reach [Formula: see text] for a 600 K LED, which highlights the potential for low-grade energy harvesting.

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Belyakova, Iryna, Vadim Piscio, Pavlo Maruschak, Oleksandr Shovkun, Volodymyr Medvid, and Mariya Markovych. "Operation of Electronic Devices for Controlling Led Light Sources When the Environment Temperature Changes." Applied System Innovation 6, no. 3 (May 20, 2023): 57. http://dx.doi.org/10.3390/asi6030057.

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Ambient temperature significantly affects the electrical and light parameters of LEDs, such as forward and reverse current, voltage drop LEDs and luminous flux. With an increase in temperature, the decrease in the intensity of LED radiation is explained by physical processes, including the phenomena of non-radiative recombination due to impurity levels, recombination on the surface, losses carriers in the barrier layers of heterostructures, etc. The increase in temperature is also significantly reduces the useful life of LEDs and the LED device in general. Drivers, which allows to stabilize the operating current with a change in the supply voltage of the device and, as the result is light flux. But in LEDs of various types, current stabilization does not lead to the stabilization of the light flux when the temperature regime of their operation changes. When changing ambient temperature in the range of +40…+60 °C, the luminous flux of LEDs is significant decreases even in the case when their current is kept constant, as we can see from documentation for most of LED types. An article analyzes the effect of temperature on electrical and light parameters LEDs with different types of drivers as part of LED lighting devices, such as LED lamps and LED spotlights, in order to offer possible constructive solutions for partial reduction or elimination of the decline problem luminous flux of LED devices under conditions of their operation at high temperatures.

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Roy, Amritendu, Rajeev Gupta, and Ashish Garg. "Multiferroic Memories." Advances in Condensed Matter Physics 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/926290.

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Multiferroism implies simultaneous presence of more than one ferroic characteristics such as coexistence of ferroelectric and magnetic ordering. This phenomenon has led to the development of various kinds of materials and conceptions of many novel applications such as development of a memory device utilizing the multifunctionality of the multiferroic materials leading to a multistate memory device with electrical writing and nondestructive magnetic reading operations. Though, interdependence of electrical- and magnetic-order parameters makes it difficult to accomplish the above and thus rendering the device to only two switchable states, recent research has shown that such problems can be circumvented by novel device designs such as formation of tunnel junction or by use of exchange bias. In this paper, we review the operational aspects of multiferroic memories as well as the materials used for these applications along with the designs that hold promise for the future memory devices.

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Vafadar, Mohammad Fazel, Rezoana Bente Arif, Qihua Zhang, and Songrui Zhao. "Effect of substrate rotation speed on AlGaN nanowire deep ultraviolet light-emitting diodes by molecular beam epitaxy." Journal of Vacuum Science & Technology B 41, no. 3 (May 2023): 030601. http://dx.doi.org/10.1116/6.0002494.

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Aluminum gallium nitride (AlGaN) nanowires by molecular beam epitaxy (MBE) have become an emerging platform for semiconductor deep ultraviolet (UV) light-emitting diodes (LEDs). Despite of the progress, much less attention has been paid to the effect of substrate rotation speed on the device performance. Herein, we investigate the effect of the substrate rotation speed on the nanowire height and diameter uniformity, as well as the electrical and optical performance of MBE-grown AlGaN nanowire deep UV LED structures with low and high substrate rotation speeds. It is found that by increasing the substrate rotation speed from 4 revolutions per minute (rpm) to 15 rpm, the statistical variation of the nanowire height and diameter is reduced significantly. Increasing the substrate rotation speed also improves the device electrical performance, with a factor of 4 reduction on the device series resistance. This improved electrical performance further transfers to the improved optical performance. The underlying mechanisms for these improvements are also discussed.

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Zhu, Zhifang, Tao Tao, Bin Liu, Ting Zhi, Yang Chen, Junchi Yu, Di Jiang, et al. "Improved Optical and Electrical Characteristics of GaN-Based Micro-LEDs by Optimized Sidewall Passivation." Micromachines 14, no. 1 (December 21, 2022): 10. http://dx.doi.org/10.3390/mi14010010.

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GaN-based Micro-LED has been widely regarded as the most promising candidate for next generation of revolutionary display technology due to its advantages of high efficiency, high brightness and high stability. However, the typical micro-fabrication process would leave a great number of damages on the sidewalls of LED pixels, especially for Micro-LEDs, thus reducing the light emitting efficiency. In this paper, sidewall passivation methods were optimized by using acid-base wet etching and SiO2 layer passivation. The optical and electrical characteristics of optimized Micro-LEDs were measured and analyzed. The internal quantum efficiency (IQE) of Micro-LED was increased to 85.4%, and the reverse leakage current was reduced down to 10−13 A at −5 V. Optimized sidewall passivation can significantly reduce the non-radiative recombination centers, improving the device performance and supporting the development of high-resolution Micro-LED display.

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Liang, Xianchao, Rui Wang, and Hong Li. "Complementary Concentrating Solar LED Lighting Device and Its Application in Architectural Design." Journal of Nanoelectronics and Optoelectronics 16, no. 7 (July 1, 2021): 1120–28. http://dx.doi.org/10.1166/jno.2021.3073.

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The shortcomings of solar LED lighting concentrators and divide and conquer power module are analyzed, and a new set of solar LED lighting devices is proposed. From the aspect of concentrating solar energy, the device redesigns the structure of the existing symmetrical inner wall lens composite parabolic concentrator (SLCPC) by comprehensively using the principles of solar photovoltaic power generation and light transmission lighting. With the assistance of an optimized coating strategy, a part of the incident solar energy is introduced into the indoor lighting (TSLCPC) to realize energy complementary without affecting the optical performance of SLCPC. Meanwhile, it adopts a bidirectional synchronous rectifier DC-DC converter with Buck-Boost as the main topology. The lighting device takes single-chip microcomputer PIC16F887 as the main control chip, which has high-performance and low power consumption. A bidirectional synchronous rectifier DC-DC converter is adopted to realize MPPT control and LED drive. The hardware design of the device is also given. In the test, although the waveform of the bidirectional DC-DC converter has some burr in forward and reverse operation, the measurement accuracy remains stable, which verifies the feasibility of the device circuit. TSLCPC has the same optical efficiency as SLCPC, and it uses escape light to improve the utilization of solar energy. The effective light-receiving angle of TSLCPC and SLCPC ranges from −30° to 30°. When the system is introduced into the buildings in Hefei, it is found that the installation angle exerts a significant impact on lighting performance of TSLCPC, and then affects the lighting performance to a certain extent. However, it is generally acceptable.

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Liang, Xianchao, Rui Wang, and Hong Li. "Complementary Concentrating Solar LED Lighting Device and Its Application in Architectural Design." Journal of Nanoelectronics and Optoelectronics 16, no. 7 (July 1, 2021): 1120–28. http://dx.doi.org/10.1166/jno.2021.3073.

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The shortcomings of solar LED lighting concentrators and divide and conquer power module are analyzed, and a new set of solar LED lighting devices is proposed. From the aspect of concentrating solar energy, the device redesigns the structure of the existing symmetrical inner wall lens composite parabolic concentrator (SLCPC) by comprehensively using the principles of solar photovoltaic power generation and light transmission lighting. With the assistance of an optimized coating strategy, a part of the incident solar energy is introduced into the indoor lighting (TSLCPC) to realize energy complementary without affecting the optical performance of SLCPC. Meanwhile, it adopts a bidirectional synchronous rectifier DC-DC converter with Buck-Boost as the main topology. The lighting device takes single-chip microcomputer PIC16F887 as the main control chip, which has high-performance and low power consumption. A bidirectional synchronous rectifier DC-DC converter is adopted to realize MPPT control and LED drive. The hardware design of the device is also given. In the test, although the waveform of the bidirectional DC-DC converter has some burr in forward and reverse operation, the measurement accuracy remains stable, which verifies the feasibility of the device circuit. TSLCPC has the same optical efficiency as SLCPC, and it uses escape light to improve the utilization of solar energy. The effective light-receiving angle of TSLCPC and SLCPC ranges from −30° to 30°. When the system is introduced into the buildings in Hefei, it is found that the installation angle exerts a significant impact on lighting performance of TSLCPC, and then affects the lighting performance to a certain extent. However, it is generally acceptable.

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Górecki, Krzysztof, and Przemysław Ptak. "Modelling mutual thermal coupling in LED modules." Microelectronics International 32, no. 3 (August 3, 2015): 152–57. http://dx.doi.org/10.1108/mi-01-2015-0013.

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Purpose – The purpose of this paper is to present an electrothermal model of the module containing power light emitting diodes (LEDs) situated on a common base. Design/methodology/approach – The electrothermal model of this device, which takes into account both self-heating and mutual thermal coupling between the diodes situated in this module, is described. Findings – The correctness of the presented model is verified experimentally, and a good agreement of the calculated and measured optical and thermal characteristics of the considered module is obtained. Research limitations/implications – The presented model can be used for different structures of the LED module, but electrical inertia in the diodes is omitted. Practical implications – The presented model was used to calculate electrical, thermal and optical waveforms of the module OSPR3XW1 containing three power LED situated on the common base. Originality/value – The presented model takes into account thermal inertia in the considered LED module and its cooling systems with mutual thermal coupling between all the diodes situated in the same module.

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Zhuravleva, J. A., N. P. Nesterkina, and E. A. Kuznetsov. "Development of a special purpose LED ultraviolet lamp in a T8 flask." Vestnik MGTU 23, no. 4 (December 30, 2020): 319–25. http://dx.doi.org/10.21443/1560-9278-2020-23-4-319-325.

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Fluorescent tubular ultraviolet lamps are used in medicine, industry, cosmetology, forensic science, and banking. During the development of the LED ultraviolet lamp in a T8 flask, a comparison of its lighting characteristics (power, energy flux, spectral distribution of radiation) with the parameters of special-purpose fluorescent lamps produced at industrial enterprises has been carried out. The design of the LED lamp includes a glass uviole tube with a diameter of 26 mm and a length of 322 mm (wall thickness is 1 mm, glass grade - SL97-3). For precise installation of the lamp in the irradiation facility and supplying electric power to it, plastic caps of the G13 pin type (the distance between the electrical contacts is 12.7 mm) are used. Measurements of electrical parameters, energy flux and spectral distribution of radiation have been carried out at nominal mains voltage on a Gooch &Housegophotocolorimetric measuring device. The developed LED lamp consumes seven times less electricity, has significantly longer (five times) expected service life and is a safer source of ultraviolet radiation, since it does not contain harmful vapors of mercury and its compounds. The LED ultraviolet lamp in a T8 flask can be used instead of the manufactured LUFT-10 lamps for special purposes, namely, in irradiators for carrying out technological processes (photochemical reactions, drying, curing), for attracting and disinsecting insects in traps, in photocopiers.

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Portan, Diana V., Despina D. Deligianni, George C. Papanicolaou, Vassilis Kostopoulos, Georgios C. Psarras, and Minos Tyllianakis. "Combined Optimized Effect of a Highly Self-Organized Nanosubstrate and an Electric Field on Osteoblast Bone Cells Activity." BioMed Research International 2019 (March 21, 2019): 1–8. http://dx.doi.org/10.1155/2019/7574635.

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The effect of an electric field within specific intensity limits on the activity of human cells has been previously investigated. However, there are a considerable number of factors that influence the in vitro development of cell populations. In biocompatibility studies, the nature of the substrate and its topography are decisive in osteoblasts bone cells development. Further on, electrical field stimulation may activate biochemical paths that contribute to a faster, more effective self-adjustment and proliferation of specific cell types on various nanosubstrates. Within the present research, an electrical stimulation device has been manufactured and optimum values of parameters that led to enhanced osteoblasts activity, with respect to the alkaline phosphatase and total protein levels, have been found. Homogeneous electric field distribution induced by a highly organized titanium dioxide nanotubes substrate had an optimum effect on cell response. Specific substrate topography in combination with appropriate electrical stimulation enhanced osteoblasts bone cells capacity to self-adjust the levels of their specific biomarkers. The findings are of importance in the future design and development of new advanced orthopaedic materials for hard tissue replacement.

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Yeh, Jih-Chao, Kuo-Lun Huang, Yung-Chin Hsiao, Yu-Han Hsu, Yun-Han Lin, Shyh-Liang Lou, and Tsong-Hai Lee. "A Rat Model of Thrombosis in Common Carotid Artery Induced by Implantable Wireless Light-Emitting Diode Device." BioMed Research International 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/724134.

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This work has developed a novel approach to form common carotid artery (CCA) thrombus in rats with a wireless implantable light-emitting diode (LED) device. The device mainly consists of an external controller and an internal LED assembly. The controller was responsible for wirelessly transmitting electrical power. The internal LED assembly served as an implant to receive the power and irradiate light on CCA. The thrombus formation was identified with animal sonography, 7T magnetic resonance imaging, and histopathologic examination. The present study showed that a LED assembly implanted on the outer surface of CCA could induce acute occlusion with single irradiation with 6 mW/cm2LED for 4 h. If intermittent irradiation with 4.3–4.5 mW/cm2LED for 2 h was shut off for 30 min, then irradiation for another 2 h was applied; the thrombus was observed to grow gradually and was totally occluded at 7 days. Compared with the contralateral CCA without LED irradiation, the arterial endothelium in the LED-irradiated artery was discontinued. Our study has shown that, by adjusting the duration of irradiation and the power intensity of LED, it is possible to produce acute occlusion and progressive thrombosis, which can be used as an animal model for antithrombotic drug development.

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Nasution, Salhazan, and Syachrodi. "PINDIT: an Online Digital Signage at Department of Electrical Engineering, University of Riau." International Journal of Electrical, Energy and Power System Engineering 4, no. 1 (February 28, 2021): 113–20. http://dx.doi.org/10.31258/ijeepse.4.1.113-120.

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Digital information boards are widely used for displaying one-way information and announcements in a fast, precise, and up-to-date manner. In the Department of Electrical Engineering University of Riau, the media used to convey information and announcements is still conventional, which is using wall magazines and banners. This study aims to build a digital information board or Papan Informasi Digital (PINDIT), a web-based information system that will be displayed on a monitor screen or LED TV and placed in front of the Electrical Engineering office. The academic community or visitors can easily access information or announcements related to campus activities through these digital information boards. Information on PINDIT can be updated by administrators from anywhere via the internet and displayed in real-time. PINDIT uses Rasberry Pi as a device that connects the information system with the LED TV screen, it also equipped with an RFID device which is used as a tool to record lecturers' attendance status in the room. We conducted Usability Testing for PINDIT on 33 respondents using the USE Questionnaire with aspects of learnability, efficiency, memorability, errors, and satisfaction. From the overall test results, PINDIT can be categorized as "Very Satisfactory" with an average percentage of each aspect of 86.23%.

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Milner, Peter. "UV LEDs and their applications." Boolean 2022 VI, no. 1 (December 6, 2022): 140–46. http://dx.doi.org/10.33178/boolean.2022.1.23.

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The purpose of this research is to design and develop a semiconductor light source emitting ultraviolet (UV) light. The final device will then be integrated into a biomedical application to assist clinicians in patient diagnosis. A light emitting diode (LED) is the specific UV source of interest, which has been the subject of major research and development over the past 20 years, with applications spanning surface disinfection to biomedical imaging. To realise the UV LED, the semiconductor structure must first be ‘grown’ which is a research area in and of itself. This project focuses specifically on taking the as-grown material of the LED and forming individual functioning devices, characterisation and then further optimisation of the growth. Challenges currently being faced include the physical constraints (electrical and optical properties) of certain materials, and extracting as much UV light as possible from the device. With 2 years left in the project, these challenges will hopefully be overcome to produce a high efficiency UV LED, integrated into a biophotonics diagnostic tool.

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Miao, Xiangyu, Wenjun Huang, and Zhaojun Liu. "P‐10.7: Investigation of Fabrication Technologies of GaN‐based Micro‐LED Devices." SID Symposium Digest of Technical Papers 54, S1 (April 2023): 806–8. http://dx.doi.org/10.1002/sdtp.16418.

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Micro-light-emitting diode (Micro-LED) is a new type of display device based on the third-generation semiconductor gallium nitride (GaN) material. Micro-LED has been applied to micro-display technology due to its huge development potential. However, the EQE of Micro-LEDs decreases with the decrease of the side wall defects, and the passivation process can reduce the sidewall damage and improve the EQE. In this study, the fabrication technology of Micro-LEDs was summarized and InGaN/GaN multi-quantum wells (MQWs) Micro-LEDs from 10 × 10 μm to 200 × 200 μm were fabricated. The improvement effect of different passivation materials on the electrical characteristics of Micro-LEDs was explored. The results showed that passivation materials could effectively reduce the leakage of the device, reduce the sidewall damage and reduce the ideal factor, among which Si3N4 had the most obvious effect.

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Enomoto, Masayoshi, Minoru Nakano, Kenji Matsushita, and Eiji Shimizu. "Half duplex optical communication system using an LED as source-and detector-device." Electronics and Communications in Japan (Part I: Communications) 72, no. 9 (September 1989): 53–62. http://dx.doi.org/10.1002/ecja.4410720906.

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Lanter, William C., Hiroyuki Kosai, Tyler Bixel, B. Allen Tolson, Jeffery Stricker, James Scofield, Navjot Brar, and Biswajit Ray. "Capacitor Characterization Study for a High Power, High Frequency Converter Application." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2010, HITEC (January 1, 2010): 000174–81. http://dx.doi.org/10.4071/hitec-jstricker-wa11.

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Recent advances in SiC power devices and high temperature magnetic and insulation materials has led to an increase in activity to develop compact, high switch rate power system components that can operate at temperatures in excess of 200°C. These efforts have highlighted the need to develop capacitor technology for high power, high frequency power filter applications, which can experience cycling over a wide range of temperature (−55 °C to 250 °C). A modeling and simulation capability was used to investigate device architecture and electrical performance relationships for a select group of wound and stacked devices, which were then evaluated for use in a power conditioning application. A finite element analysis of the device architectures was used to develop a better understanding of how magnetic fields and thermal profiles affect the performance of the capacitors in maintaining a low ripple voltage at high switch rates (>20 kHz). Both predicted electrical properties and empirical data were utilized as SPICE simulation input parameters to evaluate the performance of the different capacitors in an interleaved DC-DC boost converter model. Of interest is developing a better understanding of how the device architecture and its electrical properties affect its performance as a filtering device in a high power, high frequency application.

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Wen, J., Q. Ou, and B. Xiong. "First principle study of electronic properties of 2D MXene for MXene/metal oxides memristor application." Journal of Ovonic Research 17, no. 2 (March 2021): 147–55. http://dx.doi.org/10.15251/jor.2021.172.147.

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Physical role of a novel two-dimensional (2D) MXene material, Cr2C, in determining the electrical conduction behavior of metal oxide memristor was studied here. Today one emerging application of 2D MXene materials is possessed from its ability to accelerate the formation of the conductive filaments inside the resistive oxide-based memristor device. The cause of such an improvement however remains mysterious. To address this issue, Cr2C, was introduced into the Ag/Cr2C/Pt stack to calculate its electronic structure and conductive characteristics via density functional theory. It was found that that most regions inside the Ag/Cr2C/Pt stack were occupied by electrons. The studied stack without the presence of an energy gap indicated its metal-like property. Additionally, the investigated Ag/Cr2C/Pt stack generated lower energy barrier than other conventional MXenes such as Ti3C2 and V2N. Such low energy barrier led to higher device electron diffusivity, mobility, and electrical conductivity. This undoubtedly benefited the formation of the conductive filaments inside the memristor device

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Maridueña, Víctor Manuel, Edwin Arnaldo Castro, and Nelson Layedra. "Analysis of the Response of a Static Reactive Power Compensator to Instability and Failure in Electrical grids." Journal of Physics: Conference Series 2065, no. 1 (November 1, 2021): 012023. http://dx.doi.org/10.1088/1742-6596/2065/1/012023.

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Abstract The reliability of electrical power systems has led to the implementation of new equipment with reliable technology to solve transient failures, in recent decades flexible AC transmission systems (FACTS) have been implemented in power grids, resulting in high levels of stability and control. One of the elements used is static VAR compensators (SVC), however there is very little information about the dynamic response of the device to network instability and electrical failures, for which Simulink analyses the response of the SVC. The device consists of a 47.1 MVar reactive power compensator and a 97.6 MVar inductive reactivator compensator, implemented in a three-phase 500 kV system. The results indicate the effectiveness of response against network instability while maintaining the stable voltage of the network, but against electrical failures the type and time of failure must be considered. In the case of phase-phase faults, the response of the SVC is limited with drops of 0.52 pu.

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Alobaidy, Haider A. H., Hikmat N. Abdullah, and Tariq M. Salman. "Design of smart wireless changeover for continuous electric current feeding from power sources of variable capacities." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 4 (August 1, 2020): 3460. http://dx.doi.org/10.11591/ijece.v10i4.pp3460-3467.

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Electric power has become a vital element for life today. Despite this importance, electric power consumers in Iraq suffer from the problem of noncontinuity and daily electric power supply interruption. This problem led to the use of various sources of electric power as an alternative to compensate for the shortage of electric power provided by the Iraqi national grid. In this work, a smart wireless changeover device is designed using wireless sensor networks technology aiming to solve problem caused by the multiplicity of power sources received at home and governmental buildings in Iraq by controlling operation of some electrical devices (which consume high current) in the home or workplace automatically when changing source of electricity from one to another. This solution will help to ensure the continuity of electric current feeding from power sources of variable capacities, also, to rationalize power consumption by assigning an operation priority to electric devices. Furthermore, a statistical measurement as a case study was performed in a building with a total power consumption of 160.8 KW/h. The result showed that the device functions effectively and it is capable of achieving an average saving in power of about 50% to 86% depending on the applied priorities and case study scenario.

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Nagpal, Keshav, Erwan Rauwel, Frédérique Ducroquet, and Protima Rauwel. "Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review." Beilstein Journal of Nanotechnology 12 (September 24, 2021): 1078–92. http://dx.doi.org/10.3762/bjnano.12.80.

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Light-emitting diodes (LED) are widely employed in display applications and lighting systems. Further research on LED that incorporates carbon nanostructures and metal nanoparticles exhibiting surface plasmon resonance has demonstrated a significant improvement in device performance. These devices offer lower turn-on voltages, higher external quantum efficiencies, and luminance. De facto, plasmonic nanoparticles, such as Au and Ag have boosted the luminance of red, green, and blue emissions. When combined with carbon nanostructures they additionally offer new possibilities towards lightweight and flexible devices with better thermal management. This review surveys the diverse possibilities to combine various inorganic, organic, and carbon nanostructures along with plasmonic nanoparticles. Such combinations would allow an enhancement in the overall properties of LED.

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Miao, Xiangyu, Wenjun Huang, and Zhaojun Liu. "P‐64: Investigation of Fabrication Technologies of GaN‐based Micro‐LED Devices." SID Symposium Digest of Technical Papers 54, no. 1 (June 2023): 1722–24. http://dx.doi.org/10.1002/sdtp.16933.

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Micro‐light‐emitting diode (Micro‐LED) is a new type of display device based on the third‐generation semiconductor gallium nitride (GaN) material. Micro‐LED has been applied to micro‐display technology due to its huge development potential. However, the EQE of Micro‐LEDs decreases with the decrease of the sidewall defects, and the passivation process can reduce the sidewall damage and improve the EQE. In this study, the fabrication technology of Micro‐LEDs was summarized and InGaN/GaN multi‐quantum wells (MQWs) Micro‐LEDs from 10 × 10 μm to 200 × 200 μm were fabricated. The improvement effect of different passivation materials on the electrical characteristics of Micro‐LEDs was explored. The results showed that passivation materials could effectively reduce the leakage of the device, reduce the sidewall damage and reduce the ideal factor, among which Si 3N 4 had the most obvious effect.

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37

Liang, Si-Jia, and Jian-Guang Zhou. "Rapid Detection Device of Methamphetamine Based on Improved Light Emitting Diode Induced Fluorescence Detector." Journal of Nanoelectronics and Optoelectronics 15, no. 4 (April 1, 2020): 552–59. http://dx.doi.org/10.1166/jno.2020.2766.

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In recent years, drug abuse has become a major public health problem, drug-driving poses serious threats to the public security. For the urgent need to rapidly on-site screen drug evidence and drug abusers, we have developed a fluorescent drug detection device based on LED induction (FD-LED). The core part of the device is 365 nm high-intensity LED excitation light source, FD-LED detector' performance was tested by the fluorescent brightener OB. In this study, the FD-LED detector was evaluated, and the influence of baseline noise, baseline drift, sensitivity, detection limit and quantitative limit on the detector was analyzed, the result showed that the proposed detector had good stability and sensitivity, at the same time, the chromatographic detection conditions were set, the solution based on methamphetamine C1 sample was collocated, and combined with liquid chromatography, a detection system for methamphetamine was developed. The results showed that the minimum detection amount of the sample was 1.0 × 10–9 g/ml, and the signal-concentration relationship was obvious in the range of 1.0 ng/ml∼15.6 ng/ml. This device could provide an effective method for roadside drug testing and clinical diagnosis, and give helpful assistance to law enforcement officers.

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Chen, Huanting, Xiaofang Zhou, Shuo Lin, and Jinhai Liu. "Luminous Flux and CCT Stabilization of White LED Device With a Bilevel Driver." IEEE Photonics Journal 10, no. 1 (February 2018): 1–10. http://dx.doi.org/10.1109/jphot.2018.2793965.

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Orgulan, Sukič, and Ribič. "A Procedure for Mitigating the Light Flicker in Office LED Lighting Caused by Voltage Fluctuations." Energies 12, no. 20 (October 18, 2019): 3975. http://dx.doi.org/10.3390/en12203975.

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Progress in the development of LED technologies has reached a state which justifies the replacement of lighting with traditional light sources, not only in new buildings but also in existing, older ones. One of such replacements was used as an example of a lighting flicker study presented in this paper. The results of initial measurements indicated that Rapid Voltage Changes (RVCs) are the cause of light flicker. The procedure was introduced and described in this paper to provide the necessary actions to mitigate the light flicker in LED lighting. In order to fulfil this task, the source of locally induced voltage fluctuations has to be identified. A method of identification was developed and a multi-function office printer was identified as the source of RVCs. Using a less sensitive LED driver, changing the connection point of the interfering device, and improving the electrical installation were considered as a set of possible solutions. Laboratory measurements have shown significant sensitivity of the LED driver to RVCs. The identified source of voltage disturbances was confirmed by a simulation of supply voltage variation in the presence of such device in Matlab Simulink with the use of digital flickermeter.

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Liang, Lijuan, Wenjuan He, Rong Cao, Xianfu Wei, Sei Uemura, Toshihide Kamata, Kazuki Nakamura, Changshuai Ding, Xuying Liu, and Norihisa Kobayashi. "Non-Volatile Transistor Memory with a Polypeptide Dielectric." Molecules 25, no. 3 (January 23, 2020): 499. http://dx.doi.org/10.3390/molecules25030499.

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Organic nonvolatile transistor memory with synthetic polypeptide derivatives as dielectric was fabricated by a solution process. When only poly (γ-benzyl-l-glutamate) (PBLG) was used as dielectric, the device did not show obvious hysteresis in transfer curves. However, PBLG blended with PMMA led to a remarkable increase in memory window up to 20 V. The device performance was observed to remarkably depend on the blend ratio. This study suggests the crystal structure and the molecular alignment significantly affect the electrical performance in transistor-type memory devices, thereby provides an alternative to prepare nonvolatile memory with polymer dielectrics.

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Zhang, Ke, Yibo Liu, Hoi-sing Kwok, and Zhaojun Liu. "Investigation of Electrical Properties and Reliability of GaN-Based Micro-LEDs." Nanomaterials 10, no. 4 (April 6, 2020): 689. http://dx.doi.org/10.3390/nano10040689.

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In this paper, we report high-performance Micro-LEDs on sapphire substrates, with pixel size scaling to 20 µm and an ultra-high current density of 9902 A/cm2. The forward voltages (VF) of the devices ranged from 2.32 V to 2.39 V under an injection current density of 10 A/cm2. The size and structure-dependent effects were subsequently investigated to optimize the device design. The reliability of Micro-LED devices was evaluated under long-aging, high-temperature, and high-humidity conditions. It was found that Micro-LED devices can maintain comparable performance with an emission wavelength of about 445 nm and a full width at half maximum (FWHM) of 22 nm under extreme environments. Following this, specific analysis with four detailed factors of forward voltage, forward current, slope, and leakage current was carried out in order to show the influence of the different environments on different aspects of the devices.

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Eisenfeld, Tsion, and Avi Karsenty. "Design and Modeling of Light Emitting Nano-Pixel Structure (LENS) for High Resolution Display (HRD) in a Visible Range." Nanomaterials 10, no. 2 (January 27, 2020): 214. http://dx.doi.org/10.3390/nano10020214.

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LENS (Light Emitting Nano-pixel Structure), a new nano-metric device, was designed, simulated, and modeled for feasibility analysis, with the challenge of combining high resolution and high brightness for display, essentially adapted for Augmented Reality (AR) and Virtual Reality. The device is made of two parts: The first one is a reflective nano-cone Light Emitting Device (LED) structure to reduce the Total Internal Reflection effects (TIR), and to enable improved light extraction efficiency. The second part is a Compound Parabolic Concentrator (CPC) above the nano-LED to narrow the outgoing light angular distribution so most of the light would be “accepted” by an imaging system. Such a way is drastically limiting any unnecessary light loss. Our simulations show that the total light intensity gain generated by each part of the pixel is at least 3800% when compared to a typical flat LED. It means that, for the same electrical power consumption, the battery life duration is increased by 38. Furthermore, this improvement significantly decreases the display thermal radiation by at least 300%. Since pixel resolution is critical to offer advanced applications, an extensive feasibility study was performed, using the LightTools software package for ray tracing optimization. In addition to the simulation results, an analytical model was developed. This new device holds the potential to change the efficiency for military, professional and consumer applications, and can serve as a game changer.

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Prashant, Meenakshi, Seung Wook Yoon, GeunSik Kim, Kai Liu, and Flynn Carson. "Advanced SiP Packaging Technologies of IPD for Mobile Applications." Journal of Microelectronics and Electronic Packaging 7, no. 4 (October 1, 2010): 223–27. http://dx.doi.org/10.4071/imaps.267.

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Integrated passive device (IPD) technology was originally developed as a way to replace bulky discrete passive components, but it is now gaining popularity in ESD/EMI protection applications, as well as in RF, high-brightness LED silicon submounts, and digital and mixed-signal devices. IPD is a device realized by resistors, inductors, capacitors, filters, and so on, for electrical functions such as matching and transforming, among others. Passive devices essentially optimize overall device performance. The key benefits offered by IPDs, as compared with LTCC and laminate-embedded passive devices, are primarily a smaller form factor and higher performance. IPDs are finding applications wherever it is desirable to reduce space on the application board or to reduce cost at the system level.

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Torrisi, L., G. Salvato, M. Cutroneo, F. Librizzi, A. Torrisi, and L. Silipigni. "Source-drain electrical conduction and radiation detection in graphene-based field effect transistor (GFET)." Journal of Instrumentation 17, no. 02 (February 1, 2022): P02008. http://dx.doi.org/10.1088/1748-0221/17/02/p02008.

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Abstract Electrical measurements on a graphene field effect transistor (GFET) are presented and discussed for its characterization in vacuum and in air. In this last environment three low output power continuous wave (CW) led lasers and a UV lamp have been used to study the illumination effects at wavelengths from the near infrared (NIR) to red, green up to near UV. In air the device is sensitive to visible and UV radiation. The visible light produces charge carriers increasing the source-drain current. Instead, the UV radiation induces the graphene oxidation decreasing the source-drain current in a permanent way. Small temperature increments, up to about 55∘C, increase the electrical conduction. Larger temperatures and prolonged heating in air generate oxidation, decreasing the source-drain current. As far as the NIR radiation is concerned, no effect is observed. Therefore, these preliminary investigations indicate that the device can be employed as visible and UV radiation detector.

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Branter, Joshua, Maria Estevez-Cebrero, Mohammed Diksin, Michaela Griffin, Marcos Castellanos-Uribe, Sean May, Ruman Rahman, Richard Grundy, Surajit Basu, and Stuart Smith. "Genome-Wide Expression and Anti-Proliferative Effects of Electric Field Therapy on Pediatric and Adult Brain Tumors." International Journal of Molecular Sciences 23, no. 4 (February 11, 2022): 1982. http://dx.doi.org/10.3390/ijms23041982.

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The lack of treatment options for high-grade brain tumors has led to searches for alternative therapeutic modalities. Electrical field therapy is one such area. The Optune™ system is an FDA-approved novel device that delivers continuous alternating electric fields (tumor treating fields—TTFields) to the patient for the treatment of primary and recurrent Glioblastoma multiforme (GBM). Various mechanisms have been proposed to explain the effects of TTFields and other electrical therapies. Here, we present the first study of genome-wide expression of electrotherapy (delivered via TTFields or Deep Brain Stimulation (DBS)) on brain tumor cell lines. The effects of electric fields were assessed through gene expression arrays and combinational effects with chemotherapies. We observed that both DBS and TTFields significantly affected brain tumor cell line viability, with DBS promoting G0-phase accumulation and TTFields promoting G2-phase accumulation. Both treatments may be used to augment the efficacy of chemotherapy in vitro. Genome-wide expression assessment demonstrated significant overlap between the different electrical treatments, suggesting novel interactions with mitochondrial functioning and promoting endoplasmic reticulum stress. We demonstrate the in vitro efficacy of electric fields against adult and pediatric high-grade brain tumors and elucidate potential mechanisms of action for future study.

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Zhang, Jian Xin, Ping Juan Niu, Da Yong Gao, and Lian Gen Sun. "Research Progress on Packaging Thermal Management Techniques of High Power LED." Advanced Materials Research 347-353 (October 2011): 3989–94. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3989.

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In order to dominate the lighting market, LED needs more electrical power to be driven for higher brightness, thereby increasing thermal power dissipation, which contributes to a high heat flux of 85W/cm2 within a recent typical high power LED chip. And the junction temperature has direct influence upon the light output efficiency, device life time, emitting wavelength and reliability of LED. Therefore, effective removal of heat to maintain a safe junction temperature is the key to meet the future flux per LED requirements. Compared with other individual thermal resistances along the thermal path, thermal design for much lower packaging thermal resistance is more critical to improve the performances of LED. In this paper, major present technical researches on packaging thermal management were analyzed for high power LED, and the advantages and shortcomings of these techniques were respectively summarized. Besides, some suggestions were provided for further research in this area.

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Bokhove, O., A. Kalogirou, and W. Zweers. "From Bore–Soliton–Splash to a New Wave-to-Wire Wave-Energy Model." Water Waves 1, no. 2 (November 2019): 217–58. http://dx.doi.org/10.1007/s42286-019-00022-9.

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AbstractWe explore extreme nonlinear water-wave amplification in a contraction or, analogously, wave amplification in crossing seas. The latter case can lead to extreme or rogue-wave formation at sea. First, amplification of a solitary-water-wave compound running into a contraction is disseminated experimentally in a wave tank. Maximum amplification in our bore–soliton–splash observed is circa tenfold. Subsequently, we summarise some nonlinear and numerical modelling approaches, validated for amplifying, contracting waves. These amplification phenomena observed have led us to develop a novel wave-energy device with wave amplification in a contraction used to enhance wave-activated buoy motion and magnetically induced energy generation. An experimental proof-of-principle shows that our wave-energy device works. Most importantly, we develop a novel wave-to-wire mathematical model of the combined wave hydrodynamics, wave-activated buoy motion and electric power generation by magnetic induction, from first principles, satisfying one grand variational principle in its conservative limit. Wave and buoy dynamics are coupled via a Lagrange multiplier, which boundary value at the waterline is in a subtle way solved explicitly by imposing incompressibility in a weak sense. Dissipative features, such as electrical wire resistance and nonlinear LED loads, are added a posteriori. New is also the intricate and compatible finite-element space–time discretisation of the linearised dynamics, guaranteeing numerical stability and the correct energy transfer between the three subsystems. Preliminary simulations of our simplified and linearised wave-energy model are encouraging and involve a first study of the resonant behaviour and parameter dependence of the device.

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Li, Wenhao, Kun Wang, Junlong Li, Chaoxing Wu, Yongai Zhang, Xiongtu Zhou, and Tailiang Guo. "Working Mechanisms of Nanoscale Light-Emitting Diodes Operating in Non-Electrical Contact and Non-Carrier Injection Mode: Modeling and Simulation." Nanomaterials 12, no. 6 (March 10, 2022): 912. http://dx.doi.org/10.3390/nano12060912.

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Non-electrical contact and non-carrier injection (NEC&NCI) mode is an emerging driving mode for nanoscale light-emitting diodes (LEDs), aiming for applications in nano-pixel light-emitting displays (NLEDs). However, the working mechanism of nano-LED operating in NEC&NCI mode is not clear yet. In particular, the questions comes down to how the inherent holes and electrons in the LED can support sufficient radiation recombination, which lacks a direct physical picture. In this work, a finite element simulation was used to study the working process of the nano-LED operating in the NEC&NCI mode to explore the working mechanisms. The energy band variation, carrier concentration redistribution, emission rate, emission spectrum, and current-voltage characteristics are studied. Moreover, the effect of the thickness of insulating layer that plays a key role on device performance is demonstrated. We believe this work can provide simulation guidance for a follow-up study of NEC&NCI-LED.

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Chen, Hsiang, Yun Yang He, Min Han Lin, Shang Ren Lin, Sheng-Hao Hung, Kun Min Hsieh, Shin-Jie Tsai, and Yu-Cheng Chu. "Degradation of AlGaN/GaN Light Emitting Diodes caused by Carbon Contamination with Reverse-bias Stress Test in Water Vapor." Journal of New Materials for Electrochemical Systems 19, no. 1 (February 10, 2016): 011–13. http://dx.doi.org/10.14447/jnmes.v19i1.341.

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Resolving failure origins of AlGaN/GaN light emitting diodes (LED) has received intensive study recently. In this study, formation of GaCO3 caused by carbon contamination may result in deformation of the electrode near the surface and degrade the device. The electrochemical reactions may cause device damages. Degradation in electrical properties is observed in I-V characteristics. Forward-bias and reverse-bias EL images are used to trace the damaged areas. Furthermore, focus ion beam (FIB), scanning electron microscope (SEM), energy dispersive X-ray diffraction (EDX) are applied to examine the damaged areas. Results indicate that formation of GaCO3 may deform the electrode, generate the reverse-bias EL and cause the degradation.

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Watjanatepin, Napat, Paiboon Kiatsookkanatorn, Chaiyant Boonmee, Sarayoot Thongkullaphat, Tuanjai Archevapanich, Patcharanan Sritanauthaikorn, and Khanittha Wannakam. "Design and realization of a dual-wavelength low level light therapy for acne and face rejuvenation treatment." Indonesian Journal of Electrical Engineering and Computer Science 29, no. 1 (January 1, 2022): 147. http://dx.doi.org/10.11591/ijeecs.v29.i1.pp147-160.

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Low-level light therapy (LLLT) uses the light of wavelength between 400–700 nm to treat acne, reduce inflammation, stimulate collagen production, and rejuvenate the facial skin. This study designed and constructed a dual-wavelength LED LLLT device for the facial treatment. The light spectrum, power density, uniformity, stability, and safety of the device were analyzed. The proposed system consisted of an LED array with 415 and 633 nm wavelengths. Human machine interface with embedded system was used to control light intensity and treatment time. The phototherapy device is designed to be curvaceously sized to suit the face shape of Asian people. The results showed that the LLLT device emitted 633±5 nm red and 415±5 nm blue light with a linear adjustable light power density of 0-18.56 mW/cm2 and 0-3.70 mW/cm2, respectively. The spectrum distribution of the red and blue light was relatively constant over 30 minutes of operation. The uniformity and stability of red spectrum were about 89.9% and 95.08% and blue spectrum were 87.6% and 97.08%, respectively. The experimental face’s temperature was below 31.5 . For the future study, the LED phototherapy device will be applied for clinical research in collaboration with dermatologists.Low-level light therapy (LLLT) uses the light of wavelength between 400–700 nm to treat acne, reduce inflammation, stimulate collagen production, and rejuvenate the facial skin. This study designed and constructed a dual-wavelength LED LLLT device for the facial treatment. The light spectrum, power density, uniformity, stability, and safety of the device were analyzed. The proposed system consisted of an LED array with 415 and 633 nm wavelengths. Human machine interface with embedded system was used to control light intensity and treatment time. The phototherapy device is designed to be curvaceously sized to suit the face shape of Asian people. The results showed that the LLLT device emitted 633±5 nm red and 415±5 nm blue light with a linear adjustable light power density of 0-18.56 mW/cm2 and 0-3.70 mW/cm2, respectively. The spectrum distribution of the red and blue light was relatively constant over 30 minutes of operation. The uniformity and stability of red spectrum were about 89.9% and 95.08% and blue spectrum were 87.6% and 97.08%, respectively. The experimental face’s temperature was below 31.5 . For the future study, the LED phototherapy device will be applied for clinical research in collaboration with dermatologists.

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Journal articles on the topic 'Electrical device-LED'

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