Advanced 3D Microfabrication and Demonstration of Arrayed Electrowetting Microprisms

Beam steering is still a major limitation for many electro-optical applications which require wide-angle (+/- 45°), fast (∼ms) and continuous beam steering with a relatively simple and compact system (e.g. Laser radar, holographic 3D displays, etc.) As for the traditional mechanical beam steering approach, a bulky motorized system is limited in performance for switching speed, reliability, and system footprint. Currently available flat panel approaches include liquid crystal optical phased arrays and microelectromechanical systems, which still have major limitations like polarization dependence, small or only limited steering angles and reflective modes only. To satisfy the next generation of beam steering needs, this thesis explores arrayed electrowetting microprisms.;Electrowetting prisms operate by voltage modulation of a meniscus between two immiscible liquids by changing the contact angle on a dielectric coated electrode. Electrowetting prism has the advantages of a simple fabrication process, large scale apertures, fast switching speed, low power consumption, and wide continuous steering angles with low operation voltages. This thesis will show that electrowetting prisms theoretically provide optical performance that may supersede the performance of the liquid crystal or MEMS approaches. Presented in this thesis is a full description of the electrowetting prism development from basic single transmissive and reflective millimeter-scale prisms, to the world's first arrayed microprisms (1500 prisms). These efforts include development of a simple and scalable fabrication process, including novel 3D electrode fabrication. 1D beam steering and 2D RGB color-switching are demonstrated. Theoretical analysis and calculation of the beam deflection capability and electrode fill factor are presented. High index oil investigation is also discussed. Although further research is required before the electrowetting prism arrays are ready for real applications, the thesis represents a significant first step and proof of concept of the eventual real-world impact for electrowetting prisms.