New simple fabrication method of matrix lens arrays using resist patterns directly as electroplating moulds

Feasibility of a new lens-array fabrication method was verified. In the new method, resist patterns printed by projection-exposure lithography were directly used as lens-array moulds, and they were replicated to nickel dies using electroplating. Although the mould profiles were controlled only by the projection lithography conditions, various hemispherical lens-mould profiles were obtained. As profile parameters, curvature radius, pattern height, and top-view diameter were evaluated. Curvature radius errors were less than 2.5%. The mould profiles were faithfully replicated to nickel dies by electroplating, and the mean of absolute values of surface roughness (Ra) of the nickel dies was as small as less than 50 nm. Judging from these results, the new method is feasible for fabricating precise lens-array dies of metal nickel, and the dies will be applicable for making micro-lens arrays by infusing lens materials in them.