Integration and deployment of thick film piezoelectric actuators/sensors on organic stretch[a]ble substrates - Salowitz, Nathan Picchietti; Chang, Fu-Kuo; Christensen, R. M. (Richard M.); Senesky, Debbie; Springer, George S; Stanford University, Department of Aeronautics and Astronautics (2013)
Ultrasonic sensing systems are widely used in various applications including inspection for structural safety and material characterization. Networks of micro scale ultrasonic actuators and sensors that could be deployed and integrated into structures conforming to complex shapes could potentially revolutionize how inspections are performed. Such systems could be used to interrogate the state of the host structure on demand and in real time. These systems could also enable a new class of multi-functional materials for various new applications, such as high performance flight of unmanned aerial vehicles or tactile sensing in prosthetic devices. This thesis presents a method to integrate networks of screen printed piezoceramic actuators/sensors with organic substrates enabling the networks to be stretched and deployed over areas an order of magnitude greater than the original coverage area and conform to complex shapes. This work required integration of screen printing with non-standard MEMS and C-MOS fabrication techniques to create complete systems consisting of screen printed piezoceramics, micro-scale wires, electrodes, spin coated organic films, etc. Many limitations were overcome in the process. For example, screen printed piezoceramics require high temperature processing, on the order of 1000 °C, and are attached to the substrates they are printed upon. This prevents direct fabrication of piezoceramics on organic substrates or transfer from a temporary substrate. The method presented here overcame these limitations by creating and processing the piezoelectric devices with electrodes and wiring on a high temperature substrate. Then, in a reversal of typical fabrication methods, the target organic substrate was deposited onto the piezoelectric devices. Finally, multiple layers were used to protect the system while the high temperature substrate was etched off, releasing the complete network of piezoceramics and wiring onto an organic film. This process also enabled the micro-fabrication of multiple layers of independent sensor systems on opposite sides of the same organic film. Prototypes of the devices were fabricated and tested to verify the functionality of the network both on contiguous organic films and on stretched networks covering large areas. The capabilities demonstrated in this work provide a foundation that can be adapted to create and deploy other ultrasonic devices, MEMS, and sensor systems on organic stretchable networks.
Submitted to the Department of Aeronautics and Astronautics.
Thesis (Ph.D.)--Stanford University, 2013.
Rights: (c) Copyright 2013 by Nathan Picchietti Salowitz
Keywords: theses