Piezo films with adjustable anisotropic strain for bending actuators with tunable bending profiles

Abstract

We present a method to produce in-plane polarized piezo films with a freely adjustable ratio of the strains in orthogonal in-plane directions. They can be used in piezo bending actuators with a tunable curvature profile. The strains are obtained as mean strains from a periodic polarization pattern produced by a suitable doubly interdigitated electrode structure. This mechanism is demonstrated for several examples using PZT sheets. We further discuss how this tuning and the parameters of the electrode layout affect the overall magnitude of the displacement.

Properties of piezoceramic materials in high electric field actuator applications

“…Furthermore the change in permittivity of the PZT-5H material has been already studied by Sirohi et al by measuring the impedance of piezoceramic sheet actuators at electric fields ranging from 0.15 to 0.45 kV mm −1 [23] and the temperature dependance of the charge coefficient of PZT-5H from −125°C to +125 °C (under large electric fields (0.5 kV mm −1 )) was studied by Wang et al using strain gauges glued to the ceramic [24]. In all of these studies, however, the maximum applied electric field is at most 0.6 kV mm −1 , which is well below the maximum field strengths found in typical actuator applications [25][26][27]. While some compare different types of piezoelectric ceramics, they do not compare a set of specific materials of different manufacturers and the manufacturers, in turn, do not provide the type, composition or doping of their PZT ceramics.…”

Freeform high-speed large-amplitude deformable piezo mirrors

“…Our new approach is to deposit a reflective layer on top of a new kind of in-plane polarized piezo actuator in which the deflections arise solely from inhomogeneous in-plane deformations of a piezo film that cause the film to "pop out" of the plane. The out-of-plane displacement h(r) of such actuators with a radial electric field E(r) and piezo coefficients d31 and d33 was found to be [3]…”