Fabrication of non-spherical microlens arrays

• Main Authors: Da-Chun Lin, 林大鈞
• Other Authors: Mao-Kuo Wei
• Format: Others
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/5dhs8m

碩士 === 國立東華大學 === 材料科學與工程學系 === 100 === In this study, the surfaces of silver nanoparticles were modified using chemical reduction method, followed by mixing them into a commercial photoresist. This photoresist was then used to fabricate aspherical microlens arrays through photolithography, thermal reflow with an additional electrostatic field, molding, and UV forming processes. First, the surface modified silver nanoparticles were mixed into the photoresist. Second, this photoresist was patterned into micropillars on the indium tin oxide (ITO) substrate using photolithographic process. Third, these micropillars were transformed their shape into convex microlenses using home-made thermal-reflow apparatus. Fourth, liquid polydimethylsiloxane (PDMS) mixed with its hardener was poured on the ITO substrate and then thermally cured. The PDMS mold with concave microlenses on its surface was formed after peeling it from the ITO substrate. Finally, microlens arrays were duplicated on the polyethylene terephthalate (PET) substrate using UV forming process. Experimental results showed that expansion of the bottom size of photoresist microlenses have effectively reduced during the thermal reflow when mixed with silver nanoparticles, especially with the surface-modified nanoparticles. In addition, external electrostatic field did further decrease the expansion of microlens bottom size of the photoresist microlenses during the thermal reflow, resulted in the increase of the microlens height.