Thermal Analyses of LED Light Bars and Backlight Modules

2016 ◽  
Vol 33 (3) ◽  
pp. 331-339 ◽  
Author(s):  
M.-Y. Tsai ◽  
C.-Y. Tang ◽  
C.-E. Zheng ◽  
Y.-Y. Tsai ◽  
C.-H. Chen
Keyword(s):  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Thermal Analyses ◽  
Heat Sinks ◽  
Junction Temperature ◽  
Thermal Interface Materials ◽  
Light Emitting ◽  
Led Light ◽  
The One ◽  
Interface Materials

AbstractThe effects of various parameters, such as thermal properties of substrates, thermal interface materials (TIMs) and heat sinks on the thermal performance of the light emitting diode (LED) light bars and backlight module are investigated experimentally and numerically in terms of junction temperature (Tj) and thermal resistances from junction to air (Rj-a). The results show that the measured Rj-a of the light bars by powering-on five LEDs in the test is different from one by powering-on only one LED, resulting from the extra heat coming from the adjacent LED packages affecting the Tj for the case of powering-on five LEDs. For the modules, Rj-a is significantly reduced by using the heat sinks for all backlight modules, and aluminum and iron heat sinks do not show any obvious difference in heat dissipation along with any substrates and TIMs. Furthermore, both experimental and simulation results show that the thermal conductivity of the substrates are more important and dominant than TIM and heat sink for the Rj-a of the backlight modules concerned, and also demonstrate that the thermal field for the local model can represent the one in full-scale backlight module.

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.

Thermal Performance Evaluation and Economic Analysis of LED Integrated with Thermoelectric Cooler Package

2011 ◽  
Vol 216 ◽  
pp. 106-110 ◽  
Author(s):  
Hong Qin ◽  
Da Liang Zhong ◽  
Chang Hong Wang
Keyword(s):  
Economic Analysis ◽  
Thermal Performance ◽  
Power Dissipation ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Vital Role ◽  
Junction Temperature ◽  
Total Power ◽  
Thermoelectric Cooler ◽  
Light Emitting

Thermal management is an important issue for light emitting diodes’ utilization. For high power light emitting diode (LED), active heat dissipation method plays a vital role. As a new cooling device, thermoelectric cooler (TEC) is applied in LED packaging for the precisely temperature controlled advantage. In order to evaluate the thermal performance of the TEC packaging designs in LED, experimental measurement is used to assess the chip’s junction temperature of three different cooling models, which include the heatsink model, the heatsink and fan model and the TEC, heatsink and fan model. Based on the research, it is better to apply TEC cooling methods with the power dissipation of LED less than 35 W and the wind speed is 3.6 m/s. However, the power dissipation of TEC itself plays a vital role of the total power dissipation of LED packaging. The results of economic analysis shows that the LED integrated with TEC package achieves 22.34% and 44.73% electric energy saving under the condition of 20 W and 30 W power dissipation of the LED chip contrasts to the fluorescent lamp, but sacrifices 2.71% electric power under the condition of 10 W power dissipation of the LED chip.

Numerical Analysis for Thermal Performance of High Power Multi-Chip LED Packaging

2010 ◽  
Vol 139-141 ◽  
pp. 1433-1437
Author(s):  
Kai Lin Pan ◽  
Jiao Pin Wang ◽  
Jing Liu ◽  
Guo Tao Ren
Keyword(s):  
High Power ◽  
Heat Sink ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Junction Temperature ◽  
Light Emitting ◽  
Die Attach ◽  
Dissipation Model ◽  
Key Issues

Heat dissipation and cost are the key issues for light-emitting diode (LED) packaging. In this paper, based on the thermal resistance network model of LED packaging, three-dimensional heat dissipation model of high power multi-chip LED packaging is developed and analyzed with the application of finite element method. Temperature distributions of the current multi-chip LED packaging model are investigated systematically under the different materials of the chip substrate, die attach, and/or different structures of the heat sink and fin. The results show that the junction temperature can be decreased effectively by increasing the height of the heat sink, the width of the fin, and the thermal conductivity of the chip substrate and die attach materials. The lower cost and higher reliability for LED source can be obtained through reasonable selection of materials and structure parameters of the LED lighting system.

scholarly journals Thermal Performance of LED Filament in Flip-Chip Packaging Manufactured for Different Correlated Color Temperature

2021 ◽  
Vol 11 (19) ◽  
pp. 8844
Author(s):  
He Jiang ◽  
Jiming Sa ◽  
Cong Fan ◽  
Yiwen Zhou ◽  
Hanwen Gu ◽  
...  
Keyword(s):  
Thermal Performance ◽  
Flip Chip ◽  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Color Difference ◽  
Junction Temperature ◽  
Color Temperature ◽  
Constant Current ◽  
Light Emitting ◽  
Flip Chip Packaging

The effect of correlated color temperature (CCT) on the thermal performance of light emitting diode (LED) filament in flip-chip packaging was investigated in detail. Two filaments with different lengths were selected as the research object, and the thermal resistance of filaments under three CCT (2200 K, 2400 K, 2700 K) were studied. The optical properties and thermal parameters of the two groups of filaments were measured, and the results were analyzed combined with the color coordinate. The experimental results show that thermal properties of LED filaments is closely related to CCT. Under constant current condition, junction temperature decreases with the increase of color difference. With the change of phosphor glue and phosphorus powder ratio, the color temperature of LED filament also changes. In the filaments with the same chip structure and packaging mechanism, the higher the proportion of red phosphorescent powder, the worse the heat dissipation performance of the filament. These results show that in the design and manufacture of LED filament, it is helpful to control the CCT of LED filament under the premise of meeting the use requirements.

LED Heat Dissipation Analysis Using Composite Based Cylindrical Slug

2014 ◽  
Vol 893 ◽  
pp. 803-806 ◽  
Author(s):  
Zaliman Sauli ◽  
Rajendaran Vairavan ◽  
Vithyacharan Retnasamy
Keyword(s):  
Natural Convection ◽  
Heat Dissipation ◽  
Simulation Analysis ◽  
Light Emitting Diode ◽  
Input Power ◽  
Junction Temperature ◽  
Simulation Platform ◽  
Single Chip ◽  
Light Emitting ◽  
Convection Condition

The optical efficacy and reliability of light emitting diode is extensively influenced by the operating junction temperature of the LED. Therefore, the evaluation of junction temperature is significant. This paper reports a simulation analysis on the heat dissipation of single chip LED package with based material, copper diamond (Cu/Dia) cylindrical heat slug.Ansys version 11 was utilized as the simulation platform. The junction temperature and stress of the LED chip under natural convection condition were evaluated with varied input power of 0.1 W, 0.5 W and 1 W. Results indicated the maximum junction temperature of LED chip was attained at input power of 1 W.

A three-dimensional thermal analysis for cooling a square Light Emitting Diode by Multiwalled Carbon Nanotube-nanofluid-filled in a rectangular microchannel

2021 ◽  
Vol 13 (11) ◽  
pp. 168781402110599
Author(s):  
Mohamed Bechir Ben Hamida ◽  
Mohammed A. Almeshaal ◽  
Khalil Hajlaoui
Keyword(s):  
Heat Sink ◽  
Heat Dissipation ◽  
Cooling System ◽  
Light Emitting Diode ◽  
Three Dimensional ◽  
Junction Temperature ◽  
Engine Oil ◽  
Inlet Temperature ◽  
Rectangular Microchannel ◽  
Light Emitting

The aim of this paper is to ensure proper thermal management in order to remove and dissipate the heat produced by a square Light Emitting Diode (LED), as well as to ensure stable and safe operation by reducing the junction temperature. For this, we developed a three-dimensional code, time-dependent that solves the systems of equations for the mass, momentum, and energy using Comsol Multiphysics. After validation of this numerical 3D code, the thermal performance of a LED cooling system with three nanofluids such as MWCNT-Water, MWCNT-Ethylene Glycol, and MWCNT-Engine oil is studied numerically into account of aggregation effect. Several parameters such as: the power of the LED lamp, the inlet temperature and velocity of nanofluid, the length of the heat sink, and the length of the microchannel have been varied in order to find an optimal condition allowing a good heat dissipation from the LED chip to the heat sink. It was concluded that the use of MWCNT-Water in the microchannel is the best nanofluid that can cool the heat sink. In addition, the increase of velocity inlet of the coolant in the microchannel, the length of the heat sink, and the microchannel length while the decrease of the inlet temperature of nanofluid in the microchannel are an important factors allowing the decrease of the junction temperature of the square LED lamp.

Effect of Thermal Interface Materials on Heat Dissipation of Light-Emitting Diode Headlamps with Thermally-Conductive Plastics

2021 ◽  
Vol 21 (7) ◽  
pp. 3721-3728
Author(s):  
Dong Kyu Lee ◽  
Yu-Jung Cha ◽  
Joon Seop Kwak
Keyword(s):  
Heat Dissipation ◽  
Light Emitting Diode ◽  
Research Work ◽  
Green Energy ◽  
Thermal Interface Material ◽  
Junction Temperature ◽  
Thermal Interface ◽  
Light Emitting ◽  
Soldering Temperature ◽  
Conductive Plastics

We study the effect of thermal interface material such as thermal-conductive plastic on the dissipation of generated heat from the light-emitting diodes (LEDs) based headlamp for the application of environment-friendly green energy in vehicles. The thermal distribution and the performances of thermal-conductive plastic with heatsink are consistently investigated by using experimental and numerical results. Various thicknesses of thermal-conductive plastics from 0.3 mm to 1.0 mm used in this research work. Basically the thermal-conductive plastic reduces the thermal interface resistance between the contact of two solid surfaces. As a result, High electrical power of about 15 W (1 A and 15 V) can be possible for applying to the high-power LED package without any damage. The soldering temperature of LED package without thermal-conductive plastic shows approximately 138.7 °C which is higher compared to the LED package with thermal-conductive plastic (124.3 °C). On the other hand, the soldering temperature increases from 124.3 to 127.6 °C with increasing the thicknesses of thermal-conductive plastic. In addition, the soldering temperature decreases from 138.7 to 124.3 °C with increasing the thermal conductivities of thermal-conductive plastic. Finally, a highly thermal conductive property of thermal-conductive plastic will propose for optimum dissipation of generated heat from the LEDs-based headlamp. We also successfully estimate the junction temperature of packaged LEDs by using soldering temperature.

scholarly journals Design of a Secondary Freeform Lens of UV LED Mosquito-Trapping Lamp for Enhancing Trapping Efficiency

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 335 ◽  
Author(s):  
Wei-Hsiung Tseng ◽  
Diana Juan ◽  
Wei-Cheng Hsiao ◽  
Cheng-Han Chan ◽  
Hsin-Yi Ma ◽  
...  
Keyword(s):  
Light Intensity ◽  
Intensity Distribution ◽  
Light Emitting Diode ◽  
Trapping Efficiency ◽  
Axially Symmetric ◽  
Light Intensity Distribution ◽  
Light Emitting ◽  
Led Light ◽  
Uv Led ◽  
Freeform Lens

In this study, our proposed ultraviolet light-emitting diode (UV LED) mosquito-trapping lamp is designed to control diseases brought by insects such as mosquitoes. In order to enable the device to efficiently catch mosquitoes in a wider area, a secondary freeform lens (SFL) is designed for UV LED. The lens is mounted on a 3 W UV LED light bar as a mosquito-trapping lamp of the new UV LED light bar module to achieve axially symmetric light intensity distribution. The special SFL is used to enhance the trapping capabilities of the mosquito-trapping lamp. The results show that when the secondary freeform surface lens is applied to the experimental outdoor UV LED mosquito-trapping lamp, the trapping range can be expanded to 100π·m2 and the captured mosquitoes increased by about 300%.

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.

scholarly journals LED Rail Signals: Full Hardware Realization of Apparatus with Independent Intensity by Temperature Changes

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1291
Author(s):  
Giuseppe Schirripa Schirripa Spagnolo ◽  
Fabio Leccese
Keyword(s):  
Temperature Sensor ◽  
Energy Efficient ◽  
Light Emitting Diode ◽  
Junction Temperature ◽  
Light Emitting ◽  
Temperature Changes ◽  
Wide Range ◽  
International Regulations ◽  
Long Lifetime ◽  
Set Up

Nowadays, signal lights are made using light-emitting diode arrays (LEDs). These devices are extremely energy efficient and have a very long lifetime. Unfortunately, especially for yellow/amber LEDs, the intensity of the light is closely related to the junction temperature. This makes it difficult to design signal lights to be used in naval, road, railway, and aeronautical sectors, capable of fully respecting national and international regulations. Furthermore, the limitations prescribed by the standards must be respected in a wide range of temperature variations. In other words, in the signaling apparatuses, a system that varies the light intensity emitted according to the operating temperature is useful/necessary. In this paper, we propose a simple and effective solution. In order to adjust the intensity of the light emitted by the LEDs, we use an LED identical to those used to emit light as a temperature sensor. The proposed system was created and tested in the laboratory. As the same device as the ones to be controlled is used as the temperature sensor, the system is very stable and easy to set up.

Sign in / Sign up

Export Citation Format

Share Document