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 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.
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).
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.
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.
The purpose of this paper is to investigate the thermal behaviors of high power LED packages to enhance the thermal performances of low temperature co‐fired ceramic chip…
The purpose of this paper is to investigate the thermal behaviors of high power LED packages to enhance the thermal performances of low temperature co‐fired ceramic chip on board (LTCC‐COB) package. Thermal analysis demonstrated an improved LTCC‐COB package design that is comparable to a metal lead frame package with low thermal resistance.
The LED device developed in this study is a LTCC package mounted directly on the metal PCB. A numerical simulation was performed to investigate the thermal characteristics of the LED module using the finite volume method, which is embedded in commercial software (Fluent V.6.3). Thermal resistance and temperature measurement validate the simulated results.
The effect of the thickness of the die attach material on the thermal resistance was dominant due to low thermal conductivity, and the junction temperature decreased significantly with slight increases in thermal conductivity, especially when the value was less than 5 W/mK. The results reveal that the thermal resistance of MCPCB is about 49 per cent‐58 per cent of the junction to board thermal resistance. The thermal model results showed good agreement with experimental results.
The developed model overcomes the large thermal resistance of a conventional LTCC package for high power LED module. The extensive results have demonstrated an improved thermal design, optimal dimensions of each component and boundary conditions for high power LTCC‐COB type package.