Design, fabrication, and metrology of ultra-precision optical freeform surface for progressive addition lens with B-spline description

摘要

This paper focuses on the design, fabrication, and metrology technologies of the ultra-precision optical freeform surface for progressive addition lens (PAL). The PAL, which has a front surface with far-view zone, near-view zone, and intermediate zone, was used to remedy presbyopia by distributing optical powers of the three zones. The PAL surface is a freeform surface because of its non-symmetrical power distribution. We introduce the PAL freeform surface design methodologies, including B-spline description and its optimization. After optimization of B-spline parameters of the PAL surface, we demonstrate the fabrication and measurement technologies of the mold for PAL surface by using ultra-precision freeform machining machine with slow tool servo function and ultra-precision 3D metrology system with user-defined function.