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LED modules emitting a luminous flux, implement near-field luminance distribution or colorimetric distribution depending on emitters location. In the far field there is complete mixing of luminous flux, both in terms of quantity as well as because of distribution color parameters. To achieve these mixing light in a short distance of the LEDs is necessary to use optical elements. The article presents...
This paper designs a USB optical modem network card module based on LED indoor visible light communication. The design of the network card module includes LED modulation and reception circuit, USB interface circuit and level conversion circuit. This network card is connected to the computer's USB interface, can communicate with the LED lamp above. It can make the LED visible light communication application...
After reviewing the equivalent circuit models of the LED, LED array, and the single-loop control CCM LED boost driver, this paper presents the compensator design approach for LED driver systems. The required compensator can be designed according to the subtraction of the magnitude and phase Bode diagrams of the existing open-loop gain from the desired loop gain. The open-loop gain can be obtained...
Flyback type converters are widely used in various applications including small power LED drivers. However, they suffer from the losses from the snubber circuit. To beat this problem, previous studies investigated the lossless snubbers. However, they still have a limitation due to the additional components resulting in a high cost and low power density. In this paper, a new converter topology for...
This paper developed a portable red-blue light emitting diode phototherapy system based on the embedded technology. The device took a STM32 microprocessor as its core controller, and red and blue narrow-band LED were used as the light source, which were driven by PT4115. In order to realize the linearly adjustment of light intensity, the STM32 was used for PWM which could achieve continuously adjustable...
This study builds an automatic monitoring system for the fish pond culture environment. The purpose of this study is to reduce the financial losses in fish culture stock resulting from natural disasters, and facilitate better control of the fish pond environment. The physical water quality signals are therefore extracted using temperature, dissolved oxygen and pH sensing modules. The water heater,...
Real-time image data processing tools are proposed to enhance the spectrophotometric absorbance accuracy, using a three-wavelength LED source. The measurements of the beam spot-size allow us to determine the ray displacement in the liquid cuvette and then the corresponding refractive index.
This paper proposes an algorithm to determine the distance between vehicles for a Intelligent Transport System (ITS) using image sensor based visible light communication. Compared to existing algorithms, the proposed algorithm uses two image sensors and thus requires only one LED for distance estimation. Simulations are conducted to verify the performance of the proposed algorithm.
The Electromagnetic Compatibility (EMC) means the ability of equipment to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to other equipment in that environment. There are different methods how to check if given electrical device complies with specific emission or immunity standards. This work is focused only on radiated emissions...
Visible light communication (VLC) has recently become one of the most popular research points. VLC can provide not only illumination, but also the data communication. This technique can be applied in the indoor localization system when it transmits information of location. Global Positioning System is usually unavailable in the building. Indoor localization using VLC is a solution to solve this problem...
The visible light communications properties of a microLED-pumped inorganic perovskite quantum dot color converter are reported. Free-space data communications at 364 Mb/s, using solely the color-converted light as the data signal optical carrier, is demonstrated.
At night, accidents are more severe and involve vulnerable people, older people with disabilities, and mothers with children. Increasing the level of illumination in the pedestrian crossing area by optimally dimensioning the associated lighting system leads to the driver being alerted to the presence of a risk area and adapting the speed of movement to avoid any danger. The projected pedestrian lighting...
This paper proposes to investigate the energy efficiency and the economic impact provided by lighting retrofit in popular housing, verifying the qualitative analysis of light emitting diode lamps replacing compact fluorescents by the evaluation of electrical and lighting parameters. The study evaluated proposal by the Housing Agency of the State of Goiás, Brazil, which will replace conventional light...
Full-duplex visible light communication over a wide angle range is experimentally investigated using wide-angle LED and image sensor under fluorescent light condition. Isolation characteristics of more than 147 dB between received signal and other transmitted, reflected, and background lights are quantitatively estimated in the field of view of 70 degrees. Error free operation of full-duplex OOK visible...
The increasing popularity of automation has resulted in the development of “smart” systems for a variety of different applications. One such application is street lighting which still mostly uses very primitive methods of maintenance. The use of smart street lighting can significantly reduce power consumption and CO2 emissions and consequently also save money. This paper proposes the use of a smart...
Solid-state lighting is a field that has developed rapidly over the recent years. Visible Light Emitting Diode (LED) has achieved higher luminous efficacy than that of incandescent light, subsequently incorporated into many lighting systems in household or in workplaces. Energy saving can be achieved by utilizing adaptive lighting systems which can adapt to ambient lighting. We discuss the ability...
Chip scale package (CSP) as an advanced technology has been applied to LED lighting devices, besides electromigration (EM) in CSP under high current density has become a critical reliability issue for the future high density microelectronic packaging. In this paper, the thermal-electric-mechanical coupled analysis is performed by the flip-chip CSP LED multi-physical finite element model. Based on...
For comparing the stability and reliability of horizontal, vertical and flip LED chips, we carried on the high temperature and high current aging experiment towards to the three kinds of bare LED chips on our self-build online monitoring and accelerated life system. Most of samples shown stable performance during the entire experiment process, but there was only one flip LED chip whose illuminant,...
the increasing demand for light emitting diodes (LEDs) has been driven by a number of application categories. The construction of LEDs is somewhat similar to microelectronics, but there are functional requirements, materials, and interfaces in LEDs that make their failure modes and mechanisms unique. In this paper, the main failure modes and mechanisms of LED device and its driving module are investigated...
White light-emitting diodes (LED) are widely applied in many fields for its special advantages compared with other light sources. Chip-scale-package (CSP) is one of the hotspots in the research of microelectronics, and also the main stream and development direction to the future package technology. Within a CSP, the solder layer between LED chip and substrate is usually achieved via reflow processes...
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