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.

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.

Heat Dissipation Simulation Research of LED Downlight and Optimization of Light Source Layout

2013 ◽  
Vol 760-762 ◽  
pp. 443-450
Author(s):  
Jie Chen ◽  
Zhong Chen ◽  
Jie Chen ◽  
Xiao Hong Li ◽  
Ya Feng Shen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Light Source ◽  
Heat Load ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Measurement Methods ◽  
Simulation Software ◽  
Simulation Research ◽  
Light Emitting ◽  
Dissipation Model

In order to solve the heat dissipation problem of LED (light-emitting diode) downlight, CFD thermal simulation software was used to establish LED downlight dissipation model. Materials thermal conductivity, thermal resistance, thermal emissive values, heat load forms and other factors were all taken in considered, and then numerical simulation combined with laboratory measurement methods was used to analysis the lamps dissipation. Based on this method, focused on the dissipation effect with different LED quantities and LED ring distances, and then optimized light source layout of current LED downlight products. After experimental verification, LED working temperatures were more ideal after the light source layout optimized, and it can improve the LED lamp lifetime effectively, this result also has important practice significance in the future LED downlight design process.

scholarly journals Analysis on High-Power Seaport LED Luminaire with Uniform Light Distribution Based on Optimized Lens and Heatsink

2021 ◽  
Vol 11 (9) ◽  
pp. 4035
Author(s):  
Jinsheon Kim ◽  
Jeungmo Kang ◽  
Woojin Jang
Keyword(s):  
Light Source ◽  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Light Distribution ◽  
Light Sources ◽  
Led Light ◽  
High Power Led ◽  
Distribution Requirement ◽  
Lighting Application

In the case of light-emitting diode (LED) seaport luminaires, they should be designed in consideration of glare, average illuminance, and overall uniformity. Although it is possible to implement light distribution through auxiliary devices such as reflectors, it means increasing the weight and size of the luminaire, which reduces the feasibility. Considering the special environment of seaport luminaires, which are installed at a height of 30 m or more, it is necessary to reduce the weight of the device, facilitate replacement, and secure a light source with a long life. In this paper, an optimized lens design was investigated to provide uniform light distribution to meet the requirement in the seaport lighting application. Four types of lens were designed and fabricated to verify the uniform light distribution requirement for the seaport lighting application. Using numerical analysis, we optimized the lens that provides the required minimum overall uniformity for the seaport lighting application. A theoretical analysis for the heatsink structure and shape were conducted to reduce the heat from the high-power LED light sources up to 250 W. As a result of these analyses on the heat dissipation characteristics of the high-power LED light source used in the LED seaport luminaire, the heatsink with hexagonal-shape fins shows the best heat dissipation effect. Finally, a prototype LED seaport luminaire with an optimized lens and heat sink was fabricated and tested in a real seaport environment. The light distribution characteristics of this prototype LED seaport luminaire were compared with a commercial high-pressure sodium luminaire and metal halide luminaire.

Reliability of High-Power Light Emitting Diode Attached With Different Thermal Interface Materials

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Xin Li ◽  
Xu Chen ◽  
Guo-Quan Lu
Keyword(s):  
High Power ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Temperature Cycling ◽  
Fluorescent Light ◽  
Light Sources ◽  
Light Emitting ◽  
Die Attach ◽  
Nanosilver Paste ◽  
Interconnection Material

As a solid electroluminescent source, white light emitting diode (LED) has entered a practical stage and become an alternative to replace incandescent and fluorescent light sources. However, due to the increasing integration and miniaturization of LED chips, heat flux inside the chip is also increasing, which puts the packaging into the position to meet higher requirements of heat dissipation. In this study, a new interconnection material—nanosilver paste is used for the LED chip packaging to pursue a better optical performance, since high thermal conductivity of this material can help improve the efficiency of heat dissipation for the LED chip. The bonding ability of this new die-attach material is evaluated by their bonding strength. Moreover, high-power LED modules connected with nanosilver paste, Sn3Ag0.5Cu solder, and silver epoxy are aged under hygrothermal aging and temperature cycling tests. The performances of these LED modules are tested at different aging time. The results show that LED modules sintered with nanosilver paste have the best performance and stability.

Thermal Analysis of High Power Light Emitting Diodes Package

2011 ◽  
Vol 687 ◽  
pp. 215-221
Author(s):  
Yuan Yuan Han ◽  
Hong Guo ◽  
Xi Min Zhang ◽  
Fa Zhang Yin ◽  
Ke Chu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
High Power ◽  
Thermal Field ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Convective Heat Exchange ◽  
Input Power ◽  
Junction Temperature ◽  
Original Structure ◽  
Light Emitting

With increasing of the input power of the chips in light emitting diode (LED)， the thermal accumulation of LEDs package increases. Therefore solving the heat issue has become a precondition of high power LED application. In this paper, finite element method was used to analyze the thermal field of high power LEDs. The effect of the heatsink structure on the junction temperature was also investigated. The results show that the temperature of the chip is 95.8°C which is the highest, and it meets the requirement. The conductivity of each component affects the thermal resistance. Convective heat exchange is connected with the heat dissipation area. In the original structure of LEDs package the heat convected through the substrate is the highest, accounting for 92.58%. Three heatsinks with fin structure are designed to decrease the junction temperature of the LEDs package.

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