Experimental Investigation of EWOD Based Optical Beam Deflector
Date Issued
2012
Date
2012
Author(s)
Chien, Ying-Heng
Abstract
As technology advances, variable optical deflector plays an important role in optical systems, such as 3-D lighting systems, adaptive front lighting system, 3-D holographic displays, Ladar, to name a few. With an attempt to overcome the bulk, high cost, slow speed, and lack of agility associate with mechanical beam steering approaches such as the dual-axis gimbaled mirror, several types of non mechanical optical deflections have been proposed over the years. Despites all these efforts, developing a wide-angle, low-voltage, high speed, polarization independent, high
steering efficiency and broadband beam steering device is still a highly desirable goal.
Electrowetting optical deflector (EOD) developed previously were known to have performance characteristics such as broadband, high steering efficiency, polarization independent. The main bottleneck to be overcome lies on lowering the operating voltage. To achieve low operating voltage and wide steering angle features, we started
from the fundamental electrowetting theory to describe the limiting phenomena of contact angle saturation and analyzed the influence of the externally applied AC electric
field, the dielectric layer material, and the hydrophobic layer, etc. in this dissertation. The dielectric layers with high K and low interfacial tension between the aqueous
solution and insulating oils were investigated in order to investigate the possibility of reducing the operation voltage and the saturation of contact angle. Furthermore, we
developed insulating oil with characteristics such as high refractive index and density identical to the adjacent aqueous solution to achieve wide-angle while lessening the
influence of gravity.
Finally, we utilized 600 nm-thick P(VDF-TrFE) and 30 nm-thick AF1601 to fabricate a deflector with an aperture size of 3 mm*3 mm. The deflection was filled with the aqueous (1wt%SDS) and the mixed oil (CN:C12=67.62: 32.38) to test the beam steering angle. We demonstrated our deflector to have switching performance of 30o tilt angle of flat meniscus interface, which led to 14 o ( +_7o )beam steering angle
on two deflection axes.
Subjects
Electrowetting
Optic deflector
Low voltage
Wide-angle
Dielectric constant
Type
thesis
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