Proceedings Article | 9 April 2010
Proc. SPIE. 7642, Electroactive Polymer Actuators and Devices (EAPAD) 2010
KEYWORDS: Fabrication, Actuators, Electrodes, Polymers, Skin, Manufacturing, Ferroelectric polymers, Polymer thin films, Electroactive polymers, Polymeric actuators
Piezoceramic actuators, presently used in commercial Braille displays, are limited by the material's relatively small
strain and brittle nature. For this reason, it is a challenge to develop full page, compact, graphic Braille displays that are
affordable. A newly developed material composed of P(VDF-TrFE-CFE) terpolymer blended with 5% P(VDF-CTFE)
electrostrictive actuators exhibits large strains (~5% at 150V/μm), fast actuation (>5 mm/s), and has a relatively high
elastic modulus (1.2 GPa). This material exhibits more than double the elastic energy density and a 50% higher modulus
of the original electrostrictive terpolymer. Hence, the potential for viable actuators in compact, full page Braille displays
is greater than ever, provided actuators can be manufactured reliably in quantity. This talk presents recent work in
scaling production of such rolled actuators. Actuators extend .5 mm, are confined to the 2.5 mm grid spacing of
conventional Braille text, generate >0.5 N force and operate at less than 200V, thus meeting the primary requirements
for a commercialized Braille display. To manufacture these actuators, cast films are stretched using a roll-to-roll zone
drawing machine that is capable of producing quantities of 2 μm thick film with high quality. What follows is a
discussion of this machine, the roll-to-roll film stretching process and an assessment of the resulting stretched film for
use as linear strain actuators, like those used in our Braille cell.
