Abstract
As optics and displays technologies advance, the demand for variable optical deflector is increasing. Variable optical deflector is essential for such applications as beam steering, lighting systems, scanning head-light of cars, bar code readers, heads-up displays and two-dimensional/three-dimensional (2D/3D) display. Moreover, the variable optical deflector could be applied in the cameras to make looking under certain angle, follow objects instantly or compensate for hand moving. The traditional optical deflectors need to use the motor and the volume is too large. As the electrowetting optical deflector (EOD) is low power consumption (~ mW), together with using micro-electro-mechanical systems (MEMS) technology, the devices can be bulk replicating and size reducing. Future optical components need to be compatible with commercial electronics. However, the operating voltage for current electrowetting devices is about tens of volts. Therefore, the development of low operating voltage is the future trend. The goal of this study was to explore various approaches to achieving a low operating voltage. First, two kinds of fluoropolymers (Teflon®AF1600 and Cytop®CTL-809M) were utilized to confirm the thickness effect and wettability. Second, three different dielectric layers (SiO2, Si3N4, and Ta2O5) with the same thickness were tested to confirm the dielectric constant effect. Third, three different surfactants (sodium dodecyl sulfate (SDS), Triton X100, and Triton X15) were used to confirm the interfacial surface tension effect. Finally, the high dielectric layers (Ta2O5 and Nb2O5) were employed to test the annealing effect on the dielectric constant. In this dissertation, an EOD was proposed to test the operating voltage and liquid interface tilting. The results show that the high dielectric constants for Nb2O5 (25.5) and Ta2O5 (18.8) were achieved with annealing at 400℃ and 700℃ O2 ambiance in a conventional furnace, respectively. Based on this result, an EOD device filled with the water (containing 1% sodium dodecyl sulfate (SDS)) and dodecane was fabricated and tested. We demonstrate that the contact angle of water can change as much as 70° in dodecane/water/Cytop®/Ta2O5 system (with 11V) and dodecane/water/Cytop®/Nb2O5 system (with 9 V). Finally, the switchable apex angles of ~ ± 20° and deflection of a beam passing through the meniscus of the EOD are presented. Glass substrate is often applied in the microfluidic channels fabrication; however, it is hard to dry etching. In this research, we present our recent investigations on fabricating the microstructures on the quartz substrate. Three different etching gas mixtures, namely SF6/Ar, CF4/Ar and CHF3/Ar, with process parameters such as Ar flow ratio, bias power, ICP power, chamber gas pressure and gas total flow rate have been studied systematically. The SU-8 layer was applied as the mask layer instead of metal to avoid contamination. We found that the SU-8 is a good alternative mask material when the CF4/Ar and CHF3/Ar gas mixtures are selected as the dry etching media. Micro channel with a depth of 55 μm is fabricated, and a nearly vertical side-wall profile (86o) is achieved. The processed data gathered in this study may offer a good basic reference on the quartz dry etching for future investigation.