Microelectronic substrates like silicon, alumina and LTCC (Low Temperature Cofired Ceramics) allow for high robustness and reliability, 3D packaging (electrical connection, channels, cavities and membranes) as well as integration and application of electronic components whereas piezoceramic materials offer sensor and actuator operations. To combine the advantages of both, integrated solutions are of great interest. This paper deals with two approaches of monolithic integration, (i) screen printing of piezoceramic thick films on microelectronic substrates and subsequent post firing and (ii) integration of pre-fired piezoceramic components into green LTCC multilayer packages and subsequent sintering. Functionality of smart microsystems not only depends on the outer design and construction but to a great part on interaction of substrate and piezoceramic material properties. A thorough choice of materials as well as the understanding and prevention of chemical reactions are necessary to build effective systems.

Screen-printed lead zirconate titanate (PZT) thick film actuators are beneficial for miniaturized devices due to their flat profile and accurate net-shaped fabrication. Sintering progress and piezoelectric performance depend on the type and amount of sintering additive. Cantilever structures were fabricated by the use of screen printing technology with a systematic variation of the sintering additive content and for two different piezoceramic base materials. Their microstructure, small and large signal properties were characterized. Based on the experimental data we developed an actuator frame to lift a micro-lens array within a low-profile microscope by 115 μm

Piezoceramic thick films offer the possibility of integrated functional components in planar design. They can be applied as sensors, actuators, ultrasonic transducers, transformers and generators. Typically, piezoceramic thick films are excited through the film thickness. In contrast, in-plane mode of excitation will be beneficial especially for actuator applications. The use of interdigitated electrodes (IDEs) enables in-plane excitation of piezoceramic thick films. Actuator performance of cantilever structures with through thickness and in-plane polarised piezoceramic thick films are investigated. The performance of in-plane polarised cantilevers depends on the particular IDE spacing. Using finite element simulations of the E-field distribution, geometrical and design efficiencies are considered and compared to experimentally derived data

Piezoceramic actuators based on thick film technology offer the opportunity of integrated solutions for smart microsystems. Especially in adaptive micro-optics, where the height of devices is limited, outgassing has to be inhibited and complex actuator structures are required, screen-printed actuators are of great interest. The paper highlights our recent research on micro-positioning stages for integration into a plenoptic camera. The first concept is based on through-thickness polarized lead zirconate titanate (PZT) thick films printed on a 45 mm x 44 mm x 0.17 mm LTCC (Low-Temperature Cofired Ceramics) frame with 4-mm-wide legs. Driving with an electrical field of 2 kV/mm resulted in an upright stroke of 115 μm. The second concept combines through-thickness and in-plane polarized thick films on four cantilever beams of an Al 2 O 3 -based micro-positioning stage. Because of the combination of d 31 -and d 33 -mode of excitation, each cantilever beam will provide an s-shaped bending profile allowing for a planar and tilt-free lift of 130 μm at an electrical field of 1.66 kV/mm. Both actuator concepts were utilized to adjust position of a micro-lens array between main lens and image sensor in a plenoptic camera setup. With that, the working range of the plenoptic camera could be extended.

Traditional means of core fabrication are to glue the laminations or weld them to form the yoke structure. These means result in good yoke assemblies for shorter (<0.6 meter) magnets. However, because of weld distortions or mechanical strength limitations, welding and/or gluing techniques result in cores with poor mechanical precision or limited mechanical strength for longer cores. The SPEAR3 gradient dipole magnets are up to 1.45 meters long and require distortions of <0.05 mm. Therefore, the SPEAR3 gradient dipole core design incorporated an assembly technique, originally devised for the PEPI Insertion quadrupoles and later adapted for the ALS gradient magnets. This technique involves fabricating a rigid frame for the core, precisely stacking and compressing the laminations using hydraulic jacks and granite surfaces and straight edges, and fixing the laminations in the frame by filling the grooves between the laminations and frame using steel loaded epoxy. Although this technique has been used in the past, it has never been fully described and published. This paper is written to provide a detailed description of the procedure and to present measurement data demonstrating the mechanical precision and stiffness of the resulting product.