Here is the abstract you requested from the CICMT_2011 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Surface Micro Machined Actuators on Piezoelectric Bulk Material|
|Keywords: Membrane Actuator, Piezoelectic, Surface Electrodes|
|In previous papers the advantages of surface micro machined actuators on bulk piezoelectric substrates have been constituted. Using circular discs of piezoelectric material an easy adaption to well-known Silicon surface micro machining technologies is possible. Thus several interdigitated electrodes layouts have been positioned on a planar lead-zirconate-titanate disc via lift off process. The dimensions of that disc are 56 mm in diameter and thickness of 0.25mm. Because of an inhomogeneous electric field distribution the actuated areas on the disc conduct a symmetric deformation of the bulk material without any need of a further passive membrane, as is necessary regarding common piezoelectric membrane actuators. The most interesting deformation was shown by star shaped interdigitated electrodes, which was an overall downward movement (i.e. the side opposite the electrodes) of the actuated area but the center moved in the opposite direction about 25% of the downward movement. This phenomenon has now been further investigated, especially with regard to furthering the upward movement. Therefore the behavior of the actuated area has been more thoroughly tested, using laser vibrometry, speckle imaging and white light interferometry. With the laser vibrometry the overall movement during polarization and also actuation is quite easily detected but not the actual profile of the whole actuated area. With speckle imaging it was proven that a symmetric deformation occurs, which could be further characterized with white light interferometry. Based on the thus salvaged data, those actuators have been investigated especially concerning their deformation behavior in various clamping modes either during polarization and/or during actuation. Best results have so far been achieved with a clamping, which blocks the downward movement, but without stiff adhesion to the actuted substrate. The area of the upward movement is left free. The upward movement has been increased. This is especially interesting for piezoelectric driven normally closed micro valve application, since process technology and design can be greatly simplified.|
Technische Universitaet Muenchen