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Article
Publication date: 1 January 2006

N. Aizar Abdul Karim, P.A. Aswatha Narayana and K.N. Seetharamu

To demonstrate thermal modeling technique for a through hole light emitting diode (LED) package using a commercial computational fluid dynamic (CFD) code and to improve its…

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Abstract

Purpose

To demonstrate thermal modeling technique for a through hole light emitting diode (LED) package using a commercial computational fluid dynamic (CFD) code and to improve its thermal performance through a series of sensitivity analyses.

Design/methodology/approach

Thermal resistance of the standard through hole LED is calculated using the simulation result. The result is then compared with actual measurement to establish the correct model. Using the validated model, series of sensitivity analyses are carried out through simulation. Taking the most optimum design, a prototype of the improved LED is fabricated and the thermal resistance performance is compared with the simulation result.

Findings

The simulation result of the standard LED is close to actual measurement with 5 percent difference. The thermal resistance of the through hole LED is reduced by changing the leadframe material from mild steel to copper alloy and increasing the leadframe width. Combination of both design changes resulted in thermal resistance reduction of 51 percent.

Originality/value

This paper identified the practicality of using CFD codes in achieving fast and accurate result in thermal modeling of LED package and also offers solutions on reducing the LED thermal resistance.

Details

Microelectronics International, vol. 23 no. 1
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 21 February 2024

Mohamed Bechir Ben Hamida

This study investigates the impact of three parameters such as: number of LED chips, pitch and LED power on the junction temperature of LEDs using a best heat sink configuration…

85

Abstract

Purpose

This study investigates the impact of three parameters such as: number of LED chips, pitch and LED power on the junction temperature of LEDs using a best heat sink configuration selected according to a lower temperature. This study provides valuable insights into how to design LED arrays with lower junction temperatures.

Design/methodology/approach

To determine the best configuration of a heat sink, a numerical study was conducted in Comsol Multiphysics on 10 different configurations. The configuration with the lowest junction temperature was selected for further analysis. The number of LED chips, pitch and LED power were then varied to determine the optimal configuration for this heat sink. A general equation for the average LED temperature as a function of these three factors was derived using Minitab software.

Findings

Among 10 configurations of the rectangular heat sink, we deduce that the best configuration corresponds to the first design having 1 mm of width, 0.5 mm of height and 45 mm of length. The average temperature for this design is 50.5 C. For the power of LED equal to 50 W–200 W, the average temperature of this LED drops when the number of LED chips reduces and the pitch size decreases. Indeed, the best array-LED corresponds to 64 LED chips and a pitch size of 0.5 mm. In addition, a generalization equation for average temperature is determined as a function of the number of LED chips, pitch and power of LED which are key factors for reducing the Junction temperature.

Originality/value

The study is original in its focus on three factors that have not been studied together in previous research. A numerical simulation method is used to investigate the impact of the three factors, which is more accurate and reliable than experimental methods. The study considers a wide range of values for the three factors, which allows for a more comprehensive understanding of their impact. It derives a general equation for the average temperature of the LED, which can be used to design LED arrays with desired junction temperatures.

Details

Multidiscipline Modeling in Materials and Structures, vol. 20 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 2 August 2011

Jin Taek Kim, Cheul Ro Lee, Daesuk Kim and Byung Joon Baek

Thermal management under high heat flux is crucial to developing high‐power light‐emitting diode (LED) applications. The purpose of this paper is to propose an efficient thermal…

709

Abstract

Purpose

Thermal management under high heat flux is crucial to developing high‐power light‐emitting diode (LED) applications. The purpose of this paper is to propose an efficient thermal dissipation technique for an LED back light unit (BLU) system.

Design/methodology/approach

A typical BLU system includes an LED package (GaN on sapphire, cathode/anode, silicone encapsulant, resin plus phosphor) on a printed circuit board (PCB), a light guide panel, and an aluminum cover frame. The temperature distribution of this system has been simulated and the thermal behavior within a 3D model has been investigated using a commercial computational fluid dynamic code (FLUENT 6.3).

Findings

The authors examined the heat‐spreading effect of cover lengths ranging from 6 to 300 mm and also observed the effect of back cover thickness on the junction temperature and cover frame temperature and investigated the influence of the air gap between the package and the cover frame. Removing the air gap lowers the maximum temperature by about 6 percent. It was found that the addition of a copper layer covering the external surfaces of the LED chip enhanced the cooling efficiency. Finally, the maximum junction temperature can be decreased by more than 21 percent in the range of parameters considered by removing the air gap, adding a heat spreader, and using a thick cover frame.

Originality/value

In this paper, thermal management for efficient heat spreading through a typical BLU system without using any additional devices is investigated. Several parameters that increase the system's temperature are examined, and a combination of design features that attenuate the junction temperature is proposed.

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