Patent attributes
An equivalent to the spatial separation either side of a nominal median plane that is inherent in a bimorph (with one piezoelectric layer on one side, and the second on the other side of the plane) is attained by structurally shaping the cross-section of a simple, single piezoelectric layer (11) such that it has a multiplicity of piezoelectric portions arranged in two generally-planar groups one either side of a median plane, so that any dimension change undergone by a portion on one side of that plane will tend to bend the whole device in the opposite direction to the same sense dimension change undergone by a portion on the other side of that plane. The simple, single layer acts as though it were a bimorph if elongate and beam-like, bending along its length, one end moving up/down, or back/forth, relative to the other but with any need for an internal, electrode.
