Machine vision system for surface defect inspection of printed silicon solar cells

Solar power has become more and more important due to the decrease of the energy sources. The solar cell is the main device to transform solar power to electric power. Since the power efficiency of solar cell is decreased with defects generated in manufacturing process, defect inspection is crucial to ensure the reliability of solar cells. This paper presents a cost-effective machine vision system for surface defect inspection of printed polycrystalline silicon solar cells. The defects of printed busbars and fingers are effectively inspected by using auto-thresholding and projection techniques sequentially in the inspection process. Experimental results have demonstrated that the defect inspection of printed polycrystalline silicon solar cells is very effective with the proposed system.