Multi-LED package design, fabrication and thermal analysis

Abstract

An ultra-thin multi-LED package is designed, manufactured and its thermal performance is characterized. The objective of this study is to develop an efficient thermal modelling approach for this system which can be used for optimization of the thermal-performance of future ultra-thin designs. A high-resolution thermal imaging camera, and thermo couples were used to measure the temperature distribution of the multi-LED package and the LED-die temperature for different operating powers. Finally, we compare the thermal measurements with the Finite element simulation results. It is concluded that the modelling approach can assist in the thermal optimization of future multi-LED package designs.

A generalised approach for the estimation of junction temperature and its effect on light output

“…Poelma et al . 13 developed an efficient thermal modelling approach which can be used for optimisation of the thermal-performance of future ultra-thin designs using a thermal imaging camera and thermo-couples. In addition, Gacio et al .…”

“…Christensen and Graham 12 studied the package and system level temperature distributions of a high power (!1 W) light emitting diode (LED) array and investigated using numerical heat flow models. Poelma et al 13 developed an efficient thermal modelling approach which can be used for optimisation of the thermalperformance of future ultra-thin designs using a thermal imaging camera and thermo-couples. In addition, Gacio et al 14 tried to understand the effects of the junction temperature on the dynamic resistance of white LEDs.…”

Bias-Polarity Dependent Ultraviolet/Visible Switchable Light-Emitting Devices

“…The above fact means that the emission spectral band of a LED will be fixed once the active layer of the device is chosen. However, multicolor-switchable light-emitting devices, of which the emission band can be changed by varying the bias, are of great importance for multicolored flat panel displays, indicators, back-lights, etc. , Although many commercial approaches have been proposed, such as using a planar arrangement of red, green, and blue (RGB) color filters to subtractively create saturated RGB colors from white light, , and integrating side-by-side single-color RGB devices that produce additive multicolored emissions, such multicolored devices are always problematic due to the unavoidable energy loss caused by the filters or the high cost and complexity resulting from the integration. In view of practical use, multicolor-switchable devices should utilize a relatively simple structure, of which the color can be switched by the magnitude of applied voltage or by the polarity of the applied bias.…”