Thick-Film Piezoelectric Actuation

Diaphragm actuation Thick-film piezoelectric actuation Thin-film actuation... 

The use of deformable mirrors to compensate the aberration of astronomical images caused by the turbulence of the earth atmosphere has led to outstanding successes of ground-based astronomy. In collaboration with the Active Structures Laboratory of Bmssels University a demonstrator for a bimorph mirror was developed and manufactured as shown in Fig. 12 It consists of a silicon wafer with a diameter of 150 mm and 0,75 mm thickness as well as 91 honeycomb thick film piezoelectric actuators with 80 pm thickness, which have been screen printed at the backside of the silicon wafer. Each actuator can be driven individually to control the shape of the bimorph mirror and thus optical aberrations. 

When the development of a scientific field expands, the need for handbooks arises, wherein the information that appeared earlier in journals and conference proceedings is systematically and selectively presented. The sensor and actuator Held is now in this position. For this reason, Elsevier Science took the initiative to develop a series of handbooks with the name "Handbook of Sensors and Actuators" which will contain the most meaningful background material that is important for the sensor and actuator field. Titles like Fundamentals of Transducers, Thick Film Sensors, Magnetic Sensors, Micromachining, Piezoelectric Crystal Sensors, Robot Sensors and Intelligent Sensors will be part of this series. 

Barrow, D. A. Noteboom, R. Sayer, M. 1995. Design and fabrication of macroscopic piezoelectric actuators based on thick PZT films. Int. Ferro. 8 1-11. 

The principle setup of this device can be described as follows an ink reservoir feeds a pressure chamber which is in direct contact with a linear arrangement of microscopic nozzles, shooting out droplets of ink on demand towards the print medium (usually paper). Two principles of actuation for the pressure chamber have been successfully implemented. In the more traditional setup a piezoelectric element is employed to contract a wall of the chamber, thus increasing the pressure which leads to the ejection of an ink droplet. This principle is employed by companies such as Epson, Sharp and Tektronix, to mention a few. The limit of this technology is the size reduction of the piezoelectric actuators. In most cases, piezoceramic elements are used in hybrid integration. More recently, however, PZT deposited in thick film technology has been employed by Epson. 

Bunn CW, Alcock TC (1945) The texture of polyethylene. Trans Faraday Soc 41 317-325 Cardoso VF, Minas G, Lanceros-Mendez S (2012) Multilayer spin-coating deposition of poly (vinylidene fluoride) films for controlling thickness and piezoelectric response. Sens Actuators A Phys 192 76-80... 

Kawachi M., Yasu M. Edahiro T. Fabrication of Si02-Ti02 glass planer optical wagveguides by flame hydrolysis deposition. Electron. Lett. 1983 19 583-584 Moilanen H., Lappalainen J., Leppavuori S. Development of piezoelectric micromovement actuator fabrication using a thick film double-paste printing method. Sensors Actuators A 1994 43 357-365... 

Polymer electrets can be operated as sensors or actuators. Their operation is very similar to that of a piezoelectric material and their direct piezoelectric transducer coefficient (d33) is higher than that of solid PVDF ferroelectric polymers [97]. If a compressive force is apphed to the film, the pores will deform preferentially with respect to the polymer material. Unlike charges within the polymer will be pushed closer together and the potential measured at the contacts will change accordingly. Similarly, the application of a voltage across the electrodes will yield a change in thickness in the material. 

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