scholarly journals Optimal Combination Design of a Light Emitting Diode Matrix Applicable to a Single-Stage Flyback Driver

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5209
Author(s):  
Ming-Chang Tsou ◽  
Ming-Tse Kuo
Keyword(s):  
Taylor Series ◽  
Linear Models ◽  
Light Emitting Diode ◽  
Circuit Simulation ◽  
Characteristic Curve ◽  
Simulation Software ◽  
Characteristic Analysis ◽  
Exponential Relationship ◽  
Light Emitting ◽  
Output Load

The present study analyzed light emitting diodes (LEDs) as an output load and used a Taylor series to describe the characteristic curve based on the exponential characteristic of voltage and current. A prototype circuit of a flyback LED driver system was established to verify whether the theory is consistent with actual results. This study focused on the exponential relationship of LED voltage and current. Conventional simulations usually used linear models to present LED loads. However, the linear model resulted in considerable error between simulation and actual characteristics. Therefore, this study employed a Taylor series to describe the nonlinear characteristic of an LED load. Through precise calculations with Mathcad computation software, the error was effectively reduced. Moreover, the process clarified the influence of temperature on LEDs, which benefited the characteristic analysis of the entire system. Finally, a realized circuit of 120 W flyback LED drivers was established for conducting theory verification, including theoretic analysis and evaluation of the system design process of the flyback converter. The circuit simulation software SIMPLIS was used to demonstrate the system model, which enabled quick understanding of the system framework established in this study. Regarding LEDs, a commercially available aluminum luminaire was used as the output load. The measured results of the actual circuit and the simulation results were remarkably consistent. For the same system at the same temperature, the error between the simulation and actual results was less than 3%, which proved the reliability of the Taylor series simulation.

A Full p-Type Poly-Si TFT Shift Register for Active Matrix Displays

2010 ◽  
Vol 1245 ◽  
Author(s):  
Myoung-Hoon Jung ◽  
Hoon-Ju Chung ◽  
Young-Ju Park ◽  
Ohyun Kim
Keyword(s):  
Control Method ◽  
Light Emitting Diode ◽  
Shift Register ◽  
Active Matrix ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Active Matrix Displays ◽  
Output Load ◽  
Voltage Swing ◽  
P Type

AbstractA new shift register using p-type poly-Si thin-film transistors (TFTs) for active matrix display is proposed. It utilizes only p-type TFTs to simplify the fabrication process, and provides time-shifted output signals with a voltage swing from VSS to VDD without signal-level loss. In the proposed shift register, output is structurally separated from carry and therefore has a high immunity to output signal distortion caused by output load capacitance. We also propose a new light emitting control method using this shift register for high image quality active-matrix organic light emitting diode (AMOLED) displays. The proposed shift register was verified by simulation and measurement.

scholarly journals Improved Traffic Control in Aba using Decade Counter and Solar Reliant Traffic Light System

2019 ◽  
pp. 176-181
Author(s):  
Uchegbu Chinenye E ◽  
Inyama Kelechi
Keyword(s):  
Control System ◽  
Traffic Control ◽  
Light Emitting Diode ◽  
Circuit Simulation ◽  
Traffic Light ◽  
Light Emitting ◽  
Effective Constant ◽  
Decade Counter ◽  
Alternative Power ◽  
Incandescent Lamps

This paper is aimed at designing an efficient traffic light model for the commercial city of Aba in Abia State, Nigeria, using LED (Light Emitting Diode). LED consumes 80 – 90 percent less energy than the normal incandescent lamps, and lasts 5 – 8 years or longer. The traffic control system involves the use of decade counter and timer for the design and circuit simulation. This analysis can efficiently be implemented at intersections in the city of Aba. It also involves the use of an alternative power supply system in the case of public power failure, for an effective constant control system.

A Highly Directional Light Emitting Diode Light Guide Bar Based on Concave V-Grooves

2012 ◽  
Vol 605-607 ◽  
pp. 2019-2022
Author(s):  
Chi Feng Chen ◽  
Bo Han Lin ◽  
Shin Hong Kuo
Keyword(s):  
Light Guide ◽  
Light Emitting Diode ◽  
Simulation Software ◽  
Optical Simulation ◽  
Structure Parameters ◽  
Light Emitting ◽  
Led Light

A light emitting diode (LED) light guide bar based on concave V-grooves is investigated by using optical simulation software to control the distribution of illumination angle. The structure parameters of V-groove and the distribution of micro-prism are considered. It is found that the illumination angle of LED light guide bar is most concentrated within ±35 degrees.

The Design of Freeform Surface Fresnel Lens Used for LED Uniform Illumination

2014 ◽  
Vol 571-572 ◽  
pp. 976-979 ◽  
Author(s):  
Yi Dan Dai ◽  
En Shi Qu ◽  
Li Yong Ren ◽  
Xin Chao Du ◽  
Hai Juan Ju
Keyword(s):  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Fresnel Lens ◽  
Simulation Software ◽  
Light Distribution ◽  
Freeform Surface ◽  
Optical Simulation ◽  
Uniform Illumination ◽  
Light Emitting ◽  
Ray Tracing Simulation

This paper presents a new kind of light emitting diode(LED) secondary light distribution lens which adopts the type of Fresnel lens surface. The research purpose of this paper is to improve the LED heat dissipation efficiency of the secondary light distribution lens and the light efficiency, so as to prolong the service life of the LED. In this paper, we use the numerical method for solving the partial differential equation to establish a freeform surface lens which could produce uniform illumination, then the innovative method of combine the Fresnel lens structure with freeform surface lens was proposed. The design of freeform surface Fresnel lens allows dramatically cut the thickness of the lens (as well as the weight and volume) , it can solve the problem of difficulty in heat dissipation. By comparing the ray tracing simulation results of original freeform surface lens and freeform surface Fresnel lens in optical simulation software, experiments show that the latter not only shows the same degree of illumination uniformity, but also greatly reduced the thickness of the lens.

Real-time Light Transmittance Monitoring for Determining Polymerization Completeness of Conventional and Bulk Fill Dental Composites

2018 ◽  
Vol 43 (1) ◽  
pp. E19-E31 ◽  
Author(s):  
M Par ◽  
I Repusic ◽  
H Skenderovic ◽  
E Klaric Sever ◽  
D Marovic ◽  
...  
Keyword(s):  
Real Time ◽  
Structural Changes ◽  
Light Emitting Diode ◽  
Light Transmittance ◽  
Dental Composites ◽  
Exponential Relationship ◽  
Light Emitting ◽  
The Real ◽  
Time Changes ◽  
T Values

SUMMARY Objectives: To monitor the real-time changes in light transmittance during composite curing and to use transmittance data to determine the curing times required for a complete polymerization. Methods: Three conventional and three bulk fill composites were cured with two light-emitting diode curing units at layer thicknesses of 2 mm and 4 mm. The real-time light transmittance data were collected by a UV-Vis spectrometer in the wavelength range of 350-550 nm, plotted against time (t) and fitted to an exponential function f(t), whose first derivative ΔT(t) = df(t)/dt represented the rate of transmittance change. As the changing transmittance reflects structural changes that occur during polymerization, ΔT(t) > 0 was considered to indicate an ongoing polymerization, whereas ΔT(t) values approaching zero suggested a complete polymerization. This principle was used to determine times required for a complete polymerization (tcomplete) for each material/thickness/curing unit combination. Results: Light transmittance was significantly influenced by the material type, sample thickness, and curing unit, amounting to 2.9%-27.0% for the bulk fill and 0.7%-16.7% for the conventional composites. The values of tcomplete amounted to 15.3-23.3 seconds for the bulk fill composites at 2 mm, 20.2-33.3 seconds for the conventional composites at 2 mm, 26.9-42.1 seconds for the bulk fill composites at 4 mm, and 40.1-59.8 seconds for the conventional composites at 4 mm. Additionally, an exponential relationship was discovered between the light transmittance and tcomplete. Conclusions: Some of the tcomplete values considerably exceeded the curing times recommended by the manufacturers.

scholarly journals Modeling of led luminaires with optimal temperature operation of leds

2021 ◽  
Vol 2131 (5) ◽  
pp. 052093
Author(s):  
T A Shirobokova ◽  
D O Surinsky ◽  
S V Egorov
Keyword(s):  
Thermal Analysis ◽  
Light Emitting Diode ◽  
Operating Mode ◽  
Simulation Software ◽  
Optimal Temperature ◽  
Light Emitting ◽  
Thermal Operating

Abstract In this article the design of light-emitting diode lamps with optimum thermal operating mode of the LEDs used are considered. Thermal analysis of the model is performed using SolidWorks Simulation software.

Four-Parameter Taylor Series-Based Light-Emitting-Diode Model

2015 ◽  
Vol 3 (3) ◽  
pp. 581-588 ◽  
Author(s):  
Ray-Lee Lin ◽  
Jhong-Yan Tsai ◽  
Jose Marcos Alonso ◽  
David Gacio
Keyword(s):  
Taylor Series ◽  
Light Emitting Diode ◽  
Light Emitting
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