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[IEEE 2017 14th IEEE India Council International Conference (INDICON) - Roorkee (2017.12.15-2017.12.17)] 2017 14th IEEE India Council International Conference (INDICON) - Design and study of Cylindrical RF pill box window for 100 GHz BWO with Single side Tapered Output Coupler
摘要： The paper represents the design and implementation of a Silicon Pillar Bow Windmill used in LED output coupler at a frequency of 100 GHz with cylindrical waveguides. The design and simulation have been carried out using CST microwave studio. The designed windmill has a circular aluminum disc with a thickness of 3.19 μm and radius of 2500 μm. The circular disc is sandwiched between two circular waveguides. The designed windmill has been simulated and the return loss and insertion loss are obtained as -22.38 dB and -0.000723 dB respectively at this frequency. The designed windmill has good performance and can be used for low and medium power microwave applications.
关键词： Silicon Pillar Bow Windmill,LED output coupler,insertion loss,CST microwave studio,return loss,cylindrical waveguides
更新于2025-09-23 15:22:29
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Fluorescent Penetrant Testing by Means of Excilamps
摘要： The paper provides a brief review of modern sources of ultraviolet (UV) radiation used in fluorescent penetrant testing (FT). The differences in implementation of the method with different radiation sources (excilamps, mercury UV lamp and LED UV lamp) are revealed experimentally. It is shown that the XeCl excilamp is not inferior to other sources of UV radiation used in FT.
关键词： Penetrant testing,UV lamp,fluorescent method,LED UV flashlight,ultraviolet radiation,test sample,excilamp
更新于2025-09-23 15:22:29
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Translucent packed bed structures for high throughput photocatalytic reactors
摘要： Translucent photocatalytic reactor structures are investigated as a possible alternative to numbering up as a method for the scale-up of microreactors. The structure and the light source design is elaborated to introduce this concept. The light field was characterized using a ray tracing algorithm. A rectangular reactor made from glass was designed using borosilicate spheres small enough to create an array of interconnected microchannels in the reactor. It was found that ray tracing can be used as a proper tool to easily design multiple-LED light sources and predict respective irradiance patterns. The performance of the reactor was assessed using the apparent rate constant, the space-time yield and the photocatalytic space-time yield, a recently introduced performance parameter which takes into account the lamp power and the reactor productivity. The apparent rate constant of the reactor for an incoming irradiance of 191 W m?2 was found to be 0.82 min?1, which is, to our knowledge, in the range of microreactors and 1–2 orders of magnitude higher than any high throughput immobilized reactor in literature. With a photocatalytic space-time yield of 0.657 m3 day?1 m?3 reactor kW?1 our reactor was amongst the best reported performers in terms of productivity and energy efficiency. This performance is related to the high specific illuminated surface area of 4267 m2 m?3 and high catalyst load of 1.9 g L?1.
关键词： Light distribution,Structured reactors,Photocatalysis,Photocatalytic degradation,LED,Reactor engineering
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - High Frequency Optical Probe for BAW/SAW Devices
摘要： Optical properties of semiconductor devices for LED and OLED devices. We present a novel optical tool based on heterodyne interferometry that is capable of detecting surface and subsurface defects in semiconductor materials with high precision. The tool operates at frequencies up to 25 GHz and can achieve a detection limit of less than 1 nm. This method is particularly useful for quality control in the optoelectronics industry, as it allows for non-destructive testing of devices such as LEDs and OLEDs. Our results demonstrate that this tool can effectively identify defects that are not detectable with conventional optical microscopy.
关键词： non-destructive testing,defect detection,optoelectronics,semiconductor devices,LED,OLED,heterodyne interferometry
更新于2025-09-23 15:22:29
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Dynamic Photo-Electro-Thermal Modeling of Light-Emitting Diodes with Phosphor Coating as Light Converter
摘要： Based on the dynamic Photo-Electro-Thermal (PET) theory for LED systems, a comprehensive theory for analyzing and modeling phosphor coating in white light-emitting diodes (LEDs) as a dynamic light converter has been presented in Part-I of this paper. This Part-2 of the work provides the details of the model parameter determination, model setup and experimental verification. The procedures of obtaining the parameters in the experimental setup are explained. Using the comprehensive theory, a dynamic PET computer model of a phosphor-coated LED device has been developed. The simulation results compare well with the practical measurements, confirming the validity of the comprehensive theory in Part-1 of this paper. The new model provides novel equations for new information such as the power loss in phosphor coating and transients of the light emitted from the phosphor coating. Such information can be used for the designs of LED drivers and systems.
关键词： Phosphor-coated light-emitting diodes (PC-LED),complete PET model,photo-electro-thermal (PET) theory,light converter
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE Life Sciences Conference (LSC) - Montreal, QC, Canada (2018.10.28-2018.10.30)] 2018 IEEE Life Sciences Conference (LSC) - Design, Implementation, and Test of an Adiabatic Stimulation Back-End for Implantable Optical Stimulation Microsystems
摘要： This paper introduces a new circuit-level idea for driving optrodes in an optical stimulation system. Trying to make the stimulation circuitry energy efficient, the proposed idea is based on the basic concept of adiabatic circuits. Based on the idea proposed in this paper, a prototype stimulation circuit was developed and tested. The optical stimulation back-end also includes a micro-fabricated optrode array, specifically designed, developed, and tested for multi-channel optical stimulation in a semi-implantable optogenetic system.
关键词： optrode,optical stimulation,organic light-emitting diode (OLED),optogenetics,adiabatic circuits,LED driver
更新于2025-09-23 15:22:29
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Study of Proton Irradiation Effects on p- and n-Type GaN Based-on Two-Terminal Resistance Dependence on 380keV Proton Fluence
摘要： 380 keV proton irradiation effects are investigated on p-GaN and n-GaN layers in GaN-based light emitting diode (LED) by characterizing current-voltage (I–V) characteristics of p-n junction, and two-terminal resistance of p- and n-GaN on both type of layers in LED wafer. Two-terminal resistance on n-GaN kept its initial value after the 1 × 10^14 cm^?2 fluence, and was remained the same order after the 1 × 10^15 cm^?2 fluence. On the other hand, p-GaN showed sensitive increase in two-terminal resistance after the 1 × 10^14 cm^?2, and six orders of increase after the 1 × 10^15 cm^?2 fluence. Observed sensitive increase of resistivity in p-GaN is explained as a lower initial hole density in p-GaN than the initial electron density in n-GaN layer.
关键词： proton irradiation effects,LED,GaN
更新于2025-09-23 15:22:29
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Effect of codoping Ce <sup>3+</sup> on the luminescence properties of Sr <sub/>9</sub> Mg <sub/>1.5</sub> (PO <sub/>4</sub> ) <sub/>7</sub> :Eu <sup>2+</sup> orange-yellow phosphor
摘要： Sr9Mg1.5(PO4)7:Eu2+ has recently been reported as a promising blue light-excited orange-yellow phosphor that can be used in white LED device. Here, Ce3+-codoping is found to be an effective strategy to improve the luminescence performance of Sr9Mg1.5(PO4)7:Eu2+ phosphor. The coexistence of Eu2+ and Eu3+ ions has been verified via photoluminescence spectral analysis. The reduction of Eu3+ to Eu2+ in Sr9Mg1.5(PO4)7 lattice cannot be completed in a reducing atmosphere, but can be promoted through codoping with Ce3+ ions to a great extent, which finally increase the effective concentration of Eu2+ in the crystal lattice. The Eu3+–Eu2+ reduction mechanism is analyzed using a charge compensation model. This work not only achieves enhanced luminescence of the Sr9Mg1.5(PO4)7:Eu2+ phosphor by codoping with Ce3+ ions, but also provides new insights into the design of Ce3+/Eu2+ codoped luminescent materials.
关键词： optical materials,defects,doping,LED,europium
更新于2025-09-23 15:22:29
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The Optical Barcode Detection and Recognition Method Based on Visible Light Communication Using Machine Learning
摘要： Visible light communication (VLC) has developed rapidly in recent years. VLC has the advantages of high confidentiality, low cost, etc. It could be an effective way to connect online to offline (O2O). In this paper, an RGB-LED-ID detection and recognition method based on VLC using machine learning is proposed. Different from traditional encoding and decoding VLC, we develop a new VLC system with a form of modulation and recognition. We create different features for different LEDs to make it an Optical Barcode (OBC) based on a Complementary Metal-Oxide-Semiconductor (CMOS) senor and a pulse-width modulation (PWM) method. The features are extracted using image processing and then support vector machine (SVM) and artificial neural networks (ANN) are introduced into the scheme, which are employed as a classifier. The experimental results show that the proposed method can provide a huge number of unique LED-IDs with a high LED-ID recognition rate and its performance in dark and distant conditions is significantly better than traditional Quick Response (QR) codes. This is the first time the VLC is used in the field of Internet of Things (IoT) and it is an innovative application of RGB-LED to create features. Furthermore, with the development of camera technology, the number of unique LED-IDs and the maximum identifiable distance would increase. Therefore, this scheme can be used as an effective complement to QR codes in the future.
关键词： CMOS image sensor,machine learning,image processing,RGB-LED,visible light communication (VLC)
更新于2025-09-23 15:22:29
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Near White Light Emission and Concentration Quenching of Calcium Titanate Doped with Dysprosium (III) Phosphors
摘要： This paper reports the preparation of CaTiO3 doped with various concentrations of Dysprosium (II) using solid state reaction technique. X-ray diffraction patterns of the sample were taken. Observed XRD pattern was matched using software match2!. The pattern was matched significantly with the crystallographic open database card (COD – 96-101-1212) which is a standard card for CaTiO3. This matching exhibited that, the prepared sample is cubic in structure with space group P m ? 3 m (221). Photoluminescence (PL) studies of the samples were also done. PL intensity was found increasing with increasing dopant concentration and maximum intensity was noted at 2.0 mol% concentration of Dy3+, thereafter concentration quenching occurred. Emission Peaks were centered at 483 nm (4F9/2?6H15/2) and 576 nm (4F9/2?6H13/2) respectively. For studying the concentration quenching, the critical distance for energy transfer and electric multipolar character were estimated. The value of multipolar character expressed that, the transition in emission spectra is a dipole – dipole (d-d) transition. Commission Internationale de l’éclairage (CIE) coordinates was found as (0.36, 0.39), which is near to white light. Colour Correlated Temperature (CCT) was 4489 K which was indicative of cool appearance of the light emitted.
关键词： White LED,Concentration quenching,Photoluminescence
更新于2025-09-23 15:22:29