Improvements in the manufacturing process of achromatic doublet on glass (ADG) Fresnel lens

The manufacturing method developed to obtain Achromatic Doublet on Glass (ADG) Fresnel lenses results in an optical system with high concentration while maintains a reduced cost. Recent improvements in the manufacturing process are presented in this paper. First, an adhesion promoter has been used in order to enhance adhesion between plastic and elastomer interface. This avoids the efficiency drop caused by delamination due to changes in temperature through the day. Second, the whole lamination process has been almost completely automatized, requiring the intervention of a human operator only to place the lens inside the laminator. Finally, a new injection mold based on nickel stamper technology has been manufactured improving the geometrical characteristics of the plastic element of the lens (lower draft angle and tip rounding).