Design and fabrication of tungsten carbide mould with micro patterns imprinted by micro lithography

Core fabrication is one of the key technologies of glass moulding process used in micro optical component manufacturing. However, when the cavity size is very small and an array-type cavity is needed, a conventional diamond turning process cannot be employed. In this study, a novel core fabrication method that can be used for glass micro optical components has been developed. First, microlens array (with individual lens diameters of 36-300 μm) mould masters were produced with silicon using a photoresist reflow and a reactive ion etching process. Then, the shape of the silicon lens masters was transferred to tungsten carbide cores using a powder pressure forming and a sintering process. To further improve the surface qualities, magnetic abrasive finishing was carried out. The details of the fabrication process are presented in this paper. The characteristics of the proposed method, such as the shrinkage in the sintering process and the effects of grain size of the tungsten carbide powder and abrasive finishing process on the surface qualities, were also discussed.