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Fabrication of Binary Diffractive Lenses and the Application to LED Lighting for Controlling Luminosity Distribution

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Optics and Photonics Journal 2013年第1期3卷 67-73页

作者： Atsushi Motogaito Kazumasa Hiramatsu Division of Electrical and Electronic Engineering Graduate School of Engineering Mie University Tsu Japan

We designed and fabricated two types of binary diffractive lenses using Electron beam lithography (EBL) on optical films film for controlling LED light. In the case of the binary diffractive convex lens with 2-mm focal length, it is possible to control the luminous intensity distribution. To improve the diffraction efficiency and realize a thin LED light source, the binary diffractive lenses with 100-μm-order focal length are effective. Furthermore we fabricated and characterized the binary diffractive concave lenses for application in LED lighting. It is found that white-light LEDs are strongly diffused by using the binary diffractive concave lenses.

关键词： Light emitting Diode (LED) Luminosity Distribution Binary Diffractive Lens Electron Beam Lithography (EBL) Optical Film

Optimal Design of Thermal Dissipation for the Array Power LED by using the RSM with Genetic Algorithm

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Modeling and Numerical Simulation of Material Science 2013年第1期3卷 12-26页

作者： Rongsheng Chen Hsin-En Cheng Chihuang Huang Ray-Wen Wu Department of Engineering Science National Cheng Kung University Tainan Chinese Taipei

In accordance with the enhancement for luminous efficiency improving, LED (Light emitting Diode) has been gradually developed by combining the characteristics of small volume, impact resistance, good reliability, long life, low power consumption with multiple purposes for energy saving and environmental protection. Therefore, the array LED has been widely applied in human livings nowadays. This study applies the finite element analysis software ANSYS to analyze the thermal behavior of the array power LED work lamp which is modeled by four same-size LED with MCPCB (Metal Core Print Circuit Board) mounted on a base heat-sink. The Flotran heat flow analysis is applied to obtain the natural convection of air coefficient, while the convection value can be confirmed by the iterative method since it is set as the boundary condition for ANSYS thermal analysis to obtain the temperature distribution, accordingly the chip junction temperature and the base heat-sink temperature were followed through experiments in order to check if the simulation results meet the design requirements and coincide with the power LED product design specification. Prior to the optimal design process for chip junction temperature, the most significant parameters were first chosen by the fractional factorial design. The regressive models were respectively setup by the dual response surface method (RSM) and the mixed response surface method. Furthermore, the genetic algorithm combined with response surface method was applied to acquire the optimal design parameters, and the results were obtained from both methods, which are reviewed for comparison. Afterwards, the mixed response surface method is adopted to investigate the effects of interactions among various factors on chip junction temperature. In conclusion, it is found that the thermal conductivity of MCPCB and the height of base heat-sink are the two major significant factors. In addition, the interactive effects between chip size and thermal co

关键词： Array Power Light emitting Diode Fractional Factorial Design Response Surface Method Genetic Algorithm

Design of a Li-Fi Transceiver

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Wireless Engineering and Technology 2017年第4期8卷 71-86页

作者： Pavas Goswami Manoj Kumar Shukla Department of Electronics School of Engineering HBTU Kanpur India

The latest uproar in this era is about a technology termed as Light Fidelity or more commonly known as Li-Fi. There are currently two trends being seen: First, the extension or enrichment of wireless services and other being increased in user demand for these services, but the available RF spectrum for usage is very limited. So the new technology of Li-Fi came into picture, which uses visible light as a source of communication. Li-Fi is the most recent development which is resourceful. In this technology, LEDs are used to transmit data in the visible light spectrum. This technology can be compared with that of Wi-Fi and offers advantages like increased accessible spectrum, efficiency, security, low latency and much higher speed. This research paper aims at designing a Li-Fi transceiver using Arduino that is able to transmit digital data. The hardware has been designed using Eagle CAD (version 7.1.0) tool and Proteus design tool (version 8). The software coding is done by using Java (version 8). Successful transmission and reception of text, image and video signals is carried out on the transceiver. Hence this research work gives an innovative way of designing a transceiver which works by using off the shelf low cost components and using visible light spectrum.

关键词： Light Fidelity (Li-Fi) Visible Light Communication (VLC) Arduino Light emitting Diode (LED) Optical Wireless Communication (OWC)

Advancement in Indoor Vertical Farming for Microgreen Production

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American Journal of Plant Sciences 2019年第8期10卷 1397-1408页

作者： Preethi Rajan Rajasekaran R. Lada Mason T. MacDonald Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Truro Truro N.S. Canada

With the growing global urban population and the emergence of megacities, there is a huge demand for arable land to meet the food demand and reduce malnutrition. Conventional agricultural practices lead to deforestation of the land for crop production and agricultural intensification to produce higher yield per unit area. These activities have been established to have negative impact on the environment thereby causing soil and water pollution. It is important to consider the use of vertical farming technology, which utilizes both horizontal and vertical space, and efficiently uses nutrients, water, and time (off season production with artificial lighting) more effectively to produce higher yield per unit volume of space than the conventional outdoor farming. Microgreens are taken into consideration to be grown under innovative vertical farming technology since they are rich in phytonutrients and they can be harvested in a short period of time. This paper reviews the current growing conditions of microgreens in vertical farming such as crop selection, media, light, nutrient solution, and containers while identifying knowledge gaps. Further, study in this area may lead to improved growing conditions to help solve the global issues and challenges surrounding food security, safety, and resource optimization.

关键词： Vertical Farming Microgreens Phytonutrients BioStrate Light emitting Diodes Plant Nutrition

Polyfluorene-Polytriarylamine Block Copolymer as an Additive for Electroluminescent Devices Based on Polymer Blends

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Open Journal of Organic Polymer Materials 2013年第2期3卷 41-45页

作者： Mehdi Jahanfar Ying Tan Kousuke Tsuchiya Takeshi Shimomura Kenji Ogino Graduate School of Bio-Applications and Systems Engineering Tokyo University of Agriculture and Technology Tokyo Japan

Electroluminescent characteristics were investigated for the blue emitting devices fabricated with the blend systems consisting of hole transporting polytriarylamine (PTAA), electron transporting polyfluorene (PF), and a block copolymer with both segments (PF-b-PTAA) as an active layer in order to elucidate the relationship between the chemical nature and morphology of the active layer, and EL performance. The addition of PF-b-PTAA to PF homopolymer afforded the hole injecting and/or electron blocking ability to increase the efficiency. The addition to PF/PTAA blend keeping the chemical composition constant also improved the performance by controlling the morphology and/or the domain size in phase-separated films.

关键词： Polyfluorene Polytriarylamine Block Copolymer Polymer Blend Polymer-Light emitting Diode

Numerical Analysis on Current Transport Characteristics in Single Layer Organic Electroluminescent Devices

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Semiconductor Photonics and Technology 2002年第4期8卷 215-220,227页

作者： PENG Ying quan 1, GAO Zhao yang 1, HE Xi yuan 1, ZHANG Xu 2 (1.School of Phys. Sci. and Tech., Lanzhou University, Lanzhou 730000, CHN 2. Dept. of Phys., Gansu Education University, Lanzhou 730030, CHN) School of Phys. Sci. and Tech. Lanzhou University Lanzhou 730000 Dept. of Phys. Gansu Education University Lanzhou 730030

A new model to describe I-V characteristics of organic light emitting devices (OLEDs) is developed based on experimental results. The dependence of I-V characteristics on energy barrier, trap density and carrier mobility is analyzed. The result shows that this model combines the Fowler Nordheim tunnel theory and the trap charge limited current theory with exponential trap distribution (TCL), and it describes the current transport characteristics of OLEDs more comprehensively. The I-V characteristics follow Fowler Nordheim theory when the energy barrier is high, the trap density is small and the carrier mobility is *** other cases they follow the TCL theory.

关键词： Organic light emitting device Characteristics Numerical model

PSPICE MODELLING OF LED

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Journal of Shanghai Jiaotong university(Science) 1997年第1期2卷 85-88页

作者：陈建平

ＰＳＰＩＣＥＭＯＤＥＬＬＩＮＧＯＦＬＥＤＣｈｅｎＪｉａｎｐｉｎｇ（陈建平）（ＮａｔｉｏｎａｌＫｅｙＬａｂ．ｏｎＬｏｃａｌＦｉｂｅｒ－ＯｐｔｉｃＣｏｍｍｕｎｉｃａｔｉｏｎＮｅｔｗｏｒｋｓａｎｄＡｄｖａｎｃｅｄＯｐｔｉｃ... 详细信息

ＰＳＰＩＣＥＭＯＤＥＬＬＩＮＧＯＦＬＥＤＣｈｅｎＪｉａｎｐｉｎｇ（陈建平）（ＮａｔｉｏｎａｌＫｅｙＬａｂ．ｏｎＬｏｃａｌＦｉｂｅｒ－ＯｐｔｉｃＣｏｍｍｕｎｉｃａｔｉｏｎＮｅｔｗｏｒｋｓａｎｄＡｄｖａｎｃｅｄＯｐｔｉｃａｌＣｏｍｍｕｎｉｃａｔｉｏｎＳｙ...

关键词： PSpice modelling simulation light emitting diode(LED)

Photoluminescence of Por-Si with High-ordered Mosaic Structure Received at Long Anodic Etching p-Si (100) in the Electrolyte with an Internal Current Source

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Optics and Photonics Journal 2013年第2期3卷 217-221页

作者： K. B. Tynyshtykbaev V. B. Glazman M. A. Yeleuov A. T. Isova B. A. Rakymetov D. Muratov S. Z.Tokmoldin Institute of Physics and Technology Almaty Kazakhstan

Photoluminescence spectra and nature of light-emitting centers of a porous silicon (por-Si) samples are given. The por- Si samples had high-ordered mosaic structure, which was received under long anodic etching p-Si(100) in electrolyte with an internal current source. The photoluminescence spectra were monitored at room temperature before and after annealing in air and vacuum. Comparative analysis of photoluminescence spectra of the por-Si samples annealed at different temperatures in air and vacuum shows that the thermal annealing conditions has significant effect on the intensity and spectral content of the photoluminescence spectra. The nature of the luminescence emission centers at different temperatures and annealing conditions was discussed.

关键词： Photoluminescence Spectra Thermal Annealing emitting Centershydrides Oxides Mosaic Structure Nanocrystallite Por-Si

Aluminum Nitride for High Brightness LED Packaging Applications

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真空电子技术 2015年第5期28卷 1-5 29,29页

作者： Jonathan Harris Li Xin-yu CMC Laboratories Inc.Tempe Beijing Vacuum Electronics Research Institute

Aluminum Nitride(ALN)is a high thermal conductivity material which is being used with increasing frequency in packaging applications for high brightness LEDs(HBLED).This paper introduce Aluminum Nitride substrate fabrication process and different ALN metallization *** is clear that the most technically appropriate metallization approach for HBLED packging is *** paper explain why the cost of ALN substrate is so high and give the future of ALN in HBLED applications.

关键词： Aluminum Nitride High Brightness Light emitting Di