Two-dimensional temperature distribution measurement of light-emitting diodes by micro-hyperspectral imaging-based reflected light method.

We propose a non-contact measurement method for determining two-dimensional (2D) temperature distribution of light-emitting diodes (LEDs). This method is based on both micro-hyperspectral imaging technology and reflected light method, owning merits of both high efficiency and high spatial resolution. Blue and green bare LEDs are used as LED under test, while red and near-infrared LEDs provide incident light to avoid spectral overlapping so as to reduce measurement error. During data processing, the convolution linear filtering algorithm is employed to improve the measurement accuracy. This proposed method is compared with the micro-thermocouple and infrared thermal imaging, with their respective comparison results in fairly good agreements. For spatial resolution of 2D temperature distribution, this method increases at least one order of magnitude compared with the thermal imaging method.