Patent ID: 7353585

Claim:
A method of producing an actuator for use in an injection arrangement, the method comprising: providing a block of ferroelectric material; cutting and/or shaping the block to a final size to provide a ferroelectric sample that forms an active element of the actuator, the ferroelectric sample having first and second opposing end faces, first and second opposing side faces, and a stack of ferroelectric layers, wherein adjacent layers of said stack are separated from one another by internal electrodes arranged substantially parallel to the end faces of the sample; subsequent to the cutting and/or shaping step, applying a primary external electrode arrangement to the first and second end faces of the sample; immersing the sample and the primary electrode arrangement within a dielectric fluid; applying a primary poling voltage to the primary external electrode arrangement so as to polarize substantially the entire ferroelectric sample along a single, first polarization axis in a first polarization direction; applying a permanent secondary external electrode arrangement to the side faces of the sample so that the secondary external electrode arrangement makes contact with the internal electrodes; and applying a secondary poling voltage to the secondary external electrode arrangement so as to polarize alternate ones of the ferroelectric layers along substantially the first polarization axis in the first polarization direction and the others of the ferroelectric layers are polarized along a second, oppositely directed polarization axis, thereby to polarize substantially the entire sample and avoiding discontinuities in ferroelectric strain throughout the sample.