“…Many articles related to ball lens applications have appeared in the technical literature, however, the ball lenses using these methods is micro ball lenses or microlens array, diameters is less than 0.3mm [8][9][10][11][12][13], and the methods of fabrication are complex and the manufacturing cost is high. In this paper, we describe a new method, the sagging method, which can be used to fabricate the ball lenses which diameter are from 0.3mm to 5mm economically, and the basic performances, such as effective focal length(EFL)、back focal length(BFL) and numerical aperture(NA), are analyzed.…”