Precision And Mirror Grinding Of Optical Microlens Curved Surface Related To Its Photovoltaic Property

A hybrid of microlens array and curved surface may produce microscopic and macroscopic optic property. Hence, the microlens array is proposed on curved glass substrate of thin film solar cell to find new photovoltaic property, but its fabrication is faced with the difficulties of brittle glass material. Hence, the ductile-mode micro-grinding is proposed to replicate the precision-trued diamond wheel micro-tip on photovoltaic glass substrate. First, the visible light absorptivities of microlens curved surface were analyzed in connection with the parameters of microlens array; second, the ductile-mode removal of photovoltaic glass substrate and the effect of grinding variables on surface roughness were observed, respectively; then, the measuring model of theoretical microlens curved surface was constructed to evaluate the form errors of microscopic microlens array and macroscopic curved surface; finally, experimental photovoltaic properties of microlens curved surface were measured. It is shown that the form accuracy and the mirror surface of microlens curved surface are dominated by micrometer-scale diamond wheel micro-tip with accurate profile and integrated micro-grains protrusion respectively. Moreover, the feed speed and the spark-out number mainly influence mirror and precision micro-grindings, respectively. The microlens array error and the curved surface error reach to 6.7 μm and 10.3 μm, respectively. Besides, the roughness of microlens curved surface reached to 27 nm. When it is applied to solar cell, it enhances the power conversion efficiency of scattered light by 3.4~10.6%, and it increases the electricity generation of sunny day and cloudy day by 260% and 419% against traditional plane surface, respectively. Moreover, the electricity generation ability in cloudy day was stronger than sunny day, this is because the microlens curved surface can scatter the oblique incident light in cloudy day.