A novel method to fabricate gapless hexagonal micro-lens array

This study presents an innovative process to fabricate gapless hexagonal micro-lens array to replace expensive grey-mask method. The process includes conventional UV lithography, photoresist reflow technique, Ni-Co electroplating with high hardness and hot embossing process. The Ni-Co electroplating process with hardness larger than Hardness of Vicker (Hv) 650 plays an important role in gapless hexagonal micro-lens fabrication. The Ni-Co is deposited and covered on the reflowed half-spherical micro-lens template, uniformly by electroplating. After the electroplating process is finished, the profile of gapless hexagonal micro-lens array can be obtained known as primary master mold. The inverse primary master mold was then fabricated, which is known as secondary master mold. Subsequently, the secondary master mold served as master for hot embossing process to replicate the array pattern onto polymer material sheet. In addition, the innovative fabrication process of gapless hexagonal micro-lens array can offer a 100% fill factor to improve overall light efficiently.