Studies on a high-resolution spatial light modulator with deformable surface profile of a liquid film for optical pattern generation

Spatial light modulators (SLM) have been developed since the 1940s using different fabrication technologies. SLMs can be employed for various applications like projection displays, direct-writing systems for photolithographic processes and optical signal processing. This dissertation gives an overview of the studies on a micromechanical SLM with a deformable oil film as actuator placed on a CMOS-circuit with mirror-layer on top. The oil film deforms due to electrostatic forces at the surface where an electric field is applied. Incident light is transmitted through the deformed oil film and reflected by the mirror layer. The local oil film deformations result in a spatial phase modulation. A simple Schlieren optics can convert the phase modulation into an intensity pattern for image projection. This work presents the first SLM devices with a deformable oil film that is addressed by a CMOS active matrix. This new technology is called moving liquid mirror (MLM). Simulation, design, fabrication and measurements of first devices are described. The devices bear 256x256 pixels of 16um or 20um size. Contrast ratios of 43:1 in the 0th order of diffraction were measured. Gray scaling is possible with analogue voltage levels. Dynamic operation proved the capability of the MLM-actuators to operate at a frame rate of 200Hz. Arbitrary patterns can be loaded into the active-matrix CMOS-circuit with oil film for the projection of intensity images