Design and Fabrication of Multi-Focusing Micro lens Array with Different Numerical Apertures by using Thermal Reflow Method

作者：Park Min Kyu; Lee Ho Jun; Park Ji Sub; Kim Mugeon; Bae Jeong Min; Mahmud Imtiaz; Kim Hak Rin^*

来源：Journal of the Optical Society of Korea, 2014, 18(1): 71-77.

DOI：10.3807/JOSK.2014.18.1.071

• Microlens array
• Thermal reflow
• Multi-focusing lens
• Imprinting

We present design and fabrication of a multi-focusing microlens array (MLA) using a thermal reflow method. To obtain multi-focusing properties with different numerical apertures at the elemental lens of the MLA, double-cylinder photoresist (PR) structures with different diameters were made within the guiding pattern with both photolithographic and partial developing processes. Due to the base PR layer supporting the thermal reflow process and the guiding structure, the thermally reflowed PR structure had different radii of curvatures with lens shapes that could be precisely modeled by the initial volume of the double-cylinder PR structures. Using the PR template, the hexagonally packed multi-focusing MLA was made via the replica molding method, which showed four different focal lengths of 0.9 mm, 1.1 mm, 1.6 mm, and 2.5 mm, and four different numerical apertures of 0.1799, 0.2783, 0.3973, and 0.4775.

• 出版日期2014-2