The integration of novel EAP-based Braille cells for use in a refreshable tactile display

Abstract

Structures demonstrating the viability of both the hydraulic and latching Braille dot, and the dielectric elastomer fiber Braille dot have been fabricated and characterized. A hydraulic proof-of-concept structure has achieved the necessary volumetric change required to lift a Braille dot over 0.5mm at voltages under 1000V and at speeds under 100ms. Long bimorphs have been fabricated that demonstrate large tip displacements over 2mm that could be used to mechanically latch the Braille rod in the 'up' position to achieve the force requirement. The addition of radial prestrain in dielectric elastomer tubes has reduced the wall thickness and directed the strain in the axial direction which has had a dramatic impact on their resulting characteristics. The required bias voltage for the dielectric elastomer fiber Braille dot has been reduced from 15.5kV to 8.75kV while the Braille head tip displacement of a fabricated prototype has almost tripled on average and now also exceeds the required displacement for a refreshable Braille display. Finally, potential solutions to the current shortcomings of both designs in meeting all of the requirements for such a display are discussed.

The Design and Development of a Multi-Lingual Braille System Output Device with Audio Enhancement

“…He or she will also take full advantage of the computer applications. This mechanism also allows the representation of images [18].…”

“…It allows the translation of images into tactile displays. The images are represented as raised dots, each representing a pixel [18].…”

Seeking the ‘holy Braille’ display: might electromechanically active polymers be the solution?

“…The question is whether any of these or future solutions still based on EAPs will ever enable the much-sought-after full-page 'holy Braille' display. Ionic Conjugated polymers Cylinder [8] Ionic polymer metal composites Bender [9] Electronic Electrostrictive polymers Roll with spring core [10] Piezoelectric polymers Bender with hydraulic coupling [11] Dielectric elastomers Cylinder [11] Diaphragm [12] Buckling membrane [13] Planar multilayer stack [14] Bistable diaphragm [15] Hydrostatically coupled membranes [16] EAP: Electromechanically active polymer.…”

Towards shear tactile displays with DEAs

“…A number of different designs for DEA tactile displays have been investigated, including stack actuators [4][5][6], tubular actuators under Braille dots [7][8][9], embossed DEA bumps [10][11][12], and hydrostatically [13][14][15] or rigidly [16] coupled DEA bumps. For a more in-depth summary the reader is directed to a recent review paper [17].…”