Molded glass arrays for micro-CPV applications with very good performance

Glass molded optics have a wide range of applications in commercial industry such as for secondary optical elements in concentrator photovoltaics (CPV), optics for light emitting diodes (LEDs), etc… In micro-CPV the reduction in size of all the components demands a very good optical quality of the primary lenses to achieve high concentrations and high efficiencies without the need of secondary optics. Glass for molding is a good candidate due to benefits such as a high abbe number, great mechanical properties, low coefficient of thermal expansion (CTE), low thermal coefficient of the refractive index (dn/dT), proven reliability, and manufacturing by a straight forward compression molding process. In collaboration with the company Holophane S.A.S. in France, several arrays of plano-convex concentrator lenses were manufactured using a manual compression mold. These first prototypes have shown absolute optical efficiency over 80% at 178X using a 1mm2 multi-junction (MJ) solar cell. Further results and potential improvements are discussed.