A thermal dissipation design method for LED array structure illumination

Obtaining high-quality images plays an important role in active automatic optical inspection systems. Besides cameras, image quality is significantly affected by the illumination thermal stability. To ensure the illumination thermal stability and capture high-quality images in optical inspection systems, a thermal dissipation design method for LED array structure illumination is proposed in this paper. Firstly, the thermal resistance model of a single LED is built by analyzing its thermal resistance characteristics. Secondly, a setup with two adjacent LEDs is taken as an example to analyze junction temperature characteristics of the same color light in a LED array, and then the junction temperature model of the LED array structure illumination is developed. Finally, the thermal dissipation design method for LED array structure illumination is illustrated based on the proposed junction temperature model. Especially, the thermal design method is decomposed into two sub-problems to simplify the design process. Experimental results show that the junction temperature deviation is within -0.33%similar to 0.33% by simulation and is 2.28% by experiment, which validates the effectiveness of the proposed method.