Self-assembly microlens by hydrophilic effect and low actuation-voltage deformable mirror by ionic polymer metallic composite
Date Issued
2011
Date
2011
Author(s)
Wei, Hsiang-Chun
Abstract
In this dissertation, there are two major topics of microlens array (MLA) and deformable mirror (DM). By integrating these two components and ordinary optical component, we developed different optics system in different applications.
Self-assembled microlens array was fabricated by hydrophilic effect using Ultraviolet (UV)/ozone modification on glass substrate. The modification on SU-8 photoresist produced periodic array of hydrophilic areas on the surface by the use of shadow mask. Afterwards, the substrate was dipped in and out of diluted SU-8 photoresist. Therefore, the liquid self-assembled MLA was formed. Finally, the solid MLA was cured by UV light. SU-8 photoresist has good chemical and mechanical strength, so it is suitable for MLA. Besides, the fabricated MLA is transparent so that there has no need for etch transferring. It decreases the process complexity a lot. Meanwhile, because of the polar molecular of SU-8 photoresist, the curvature of the microlens can be enlarged by applying external electric field. The surface roughness could be improved as well. This method provides a low cost, low time consumption, no etch transfer, low temperature, and no photo lithography method to fabricate MLA. We applied this method to fabricated microlens on a light emitting diode (LED) chip with precisely alignment. That improved the extraction efficiency and increased the viewing angle. Besides, we developed a more sensitive and larger dynamic ranged Shack-Hartmann wavefront sensor by using the developed long focal length MLA using double layer thermal reflow method. We also compared it with the commercial product.
We developed a thin autofocus camera module by using the developed micro electro mechanical systems (MEMS) organic deformable mirror (DM). It included a focus-varying optical system, and autofocus algorithm using Tenengrad image sharpness function and percentage-drop method. Besides, because of the high actuation voltage (~150 V), we adopt an ionic-conductive polymer composite to fabricate DM. IPMC is a polymer actuator with the advantage of low actuation voltage and large displacement. We built a simplified grey box model and simulate the deformation shape by using finite element method software, ANSYSR. A gear shaped IPMC DM was designed and demonstrated. It had the advantage of low actuation voltage and large optical power. Meanwhile, because of the bi-directional deformation ability, the DM with both positive and negative optical power was achieved.
Finally, we believe these research topics could inspire the related researchers and might have some benefit to the human.
Subjects
microlens array
SU-8 photoresist
hydrophilic
wavefront sensor
deformable mirror
ionic-conductive polymer metal composite
Type
thesis
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