Conception and design of a lighting system based on Light Emitting Diodes for spectrum simulation

2016 ◽  
Author(s):  
Klaus T. Martin ◽  
Olinto C. B. de Araujo ◽  
Saul A. Bonaldo ◽  
Marcelo F. da Silva
Keyword(s):  
Light Emitting Diodes ◽  
Lighting System ◽  
Light Emitting ◽  
Spectrum Simulation

Cost-Effective Light-Mixing Module for Solar-Lighting System Appended With Auxiliary RGBW Light-Emitting Diodes

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
An Chi Wei ◽  
Shih Chieh Lo ◽  
Ju-Yi Lee ◽  
Hong-Yih Yeh
Keyword(s):  
Light Source ◽  
Light Emitting Diodes ◽  
Cylindrical Tube ◽  
Cost Effective ◽  
Lighting System ◽  
Optical Efficiency ◽  
Light Emitting ◽  
Solar Lighting ◽  
Lighting Systems ◽  
Main Components

A light-mixing module consisting of a compound parabolic concentrator (CPC) and a light-mixing tube is proposed herein to realize a uniform and efficient solar-lighting system. In this lighting system, the sunlight collected into a fiber and then guided to an indoor destination is the principal light source, while an auxiliary light source including multiple red, green, blue, and white (RGBW) light-emitting diodes (LEDs) is controlled by an auto-compensating module. To mix the principal and the auxiliary sources and to realize the uniform illumination, the light-mixing tube was coated with BaSO4 and optimized as a cylindrical tube. The design of the light-mixing tube is described and discussed in this article. According to the simulated results, the uniformity and the optical efficiency of the designed light-mixing tube are 82.9% and 85.7%, respectively, while from the experimental results, the uniformity of 85.9% and the optical efficiency of 83.3% have been obtained. In terms of the common indoor-lighting standards and the specifications of commercial components used in lighting systems, the proposed light-mixing module has demonstrated the high uniformity and acceptable optical efficiency. Additionally, since the main components of the light-mixing module can be designed as plastic optics, a cost-effective light-mixing module and a profitable lighting system can be realized. Thus, the performance and the price of the proposed light-mixing module fit the demands of the illumination market, while the proposed system shows the potential for indoor solar-lighting applications.

Conceptual Development of Automotive Forward Lighting System Using White Light Emitting Diodes

2009 ◽  
Vol 2 (1) ◽  
pp. 201-211 ◽  
Author(s):  
Beshoy Morkos ◽  
Prabhu Shankar ◽  
Sudhakar Teegavarapu ◽  
Ashwin Michaelraj ◽  
Joshua D. Summers ◽  
...  
Keyword(s):  
White Light ◽  
Conceptual Development ◽  
Light Emitting Diodes ◽  
Lighting System ◽  
Light Emitting ◽  
White Light Emitting Diodes

scholarly journals Development and Validation of a Camera-Based Illumination Controller for People Detection, Tracking and Recognition using Computational Intelligence

2019 ◽  
Vol 8 (2) ◽  
pp. 3181-3185
Keyword(s):  
Face Recognition ◽  
Light Emitting Diodes ◽  
Vision System ◽  
Image Sensor ◽  
Power Source ◽  
Lighting System ◽  
Electric Grid ◽  
Light Emitting ◽  
Led Lighting ◽  
Surveillance Applications

Illumination is crucial in human activities and in machine vision applications. For indoor surveillance applications, Infrared (IR) Light Emitting Diodes (LEDs) are the common means of providing illumination to the camera to cause no discomfort to human occupants. While IR provides non-obtrusive illumination for the camera, the same energy consumed does not provide the illumination to indoor spaces of the building. This is important if the premises where the camera is installed is not connected to the main power source or electric grid but derives energy from renewable sources. In this work, an illumination controller based on fuzzy logic system is developed and integrated to a vision system and an LED lighting system to provide a constant level of illumination to an object regardless of its distance from the image sensor. The computer vision system performs human object detection and face recognition and outputs fuzzy values representing the inferred distance of detected objects where the fuzzy system generates crisp output of duty cycle settings for the PWM controller for the LED lighting system to provide the required illumination needed by the vision system. Optimum illumination level for the vision system to perform the detection, tracking and face recognition operations must be provided by the system. Using visible Light Emitting Diodes as source of illumination, the system provides illumination both for the proper operation of the camera and human personnel monitoring the premises where the system is installed. This feature is significant in energy-constrained surveillance applications or where there is no power source derived from the electric grid.

A tunable lighting system integrated by inorganic and transparent organic light-emitting diodes

2014 ◽  
Vol 10 (3) ◽  
pp. 198-201
Author(s):  
Jing-jing Zhang ◽  
Tao Zhang ◽  
Ya-fang Jin ◽  
Shi-shen Liu ◽  
Shi-dong Yuan ◽  
...  
Keyword(s):  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Lighting System ◽  
Light Emitting ◽  
Organic Light

Injecting Inter-Layers and the Built-in Potential of Blue Polymer Light-Emitting Diodes

2000 ◽  
Vol 660 ◽  
Author(s):  
Thomas M. Brown ◽  
Ian S. Millard ◽  
David J. Lacey ◽  
Jeremy H. Burroughes ◽  
Richard H. Friend ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Light Emitting Diodes ◽  
Basic Structure ◽  
Thin Layers ◽  
Carrier Injection ◽  
Semiconducting Polymer ◽  
Light Emitting ◽  
Physical Mechanisms ◽  
Organic Solid ◽  
Polymer Light Emitting Diodes

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.

Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

2003 ◽  
Vol 764 ◽  
Author(s):  
X. A. Cao ◽  
S. F. LeBoeuf ◽  
J. L. Garrett ◽  
A. Ebong ◽  
L. B. Rowland ◽  
...  
Keyword(s):  
Quantum Well ◽  
Light Emitting Diodes ◽  
Multiple Quantum Well ◽  
Light Output ◽  
Localized States ◽  
Multiple Quantum ◽  
Nonradiative Recombination ◽  
Light Emitting ◽  
Temperature Range ◽  
Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

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