Core-free rolled actuators for Braille displays using P(VDF-TrFE-CFE)

Area of Science:

• Materials Science
• Engineering
• Biomedical Engineering

Background:

• Refreshable Braille displays necessitate numerous small-diameter actuators for pin manipulation.
• Electrostrictive polymers, specifically P(VDF-TrFE-CFE) terpolymers, exhibit potential for high strain and actuation force at modest electric fields, suitable for Braille applications.

Purpose of the Study:

• To develop and evaluate core-free tubular actuators utilizing P(VDF-TrFE-CFE) terpolymer for Braille display applications.
• To integrate these actuators into a functional Braille cell prototype.

Main Methods:

• Solution casting of terpolymer films, stretching to 6 μm thickness, and electrode application.
• Lamination into a bilayer, rolling into 2 mm diameter tubes, bonding, and contact provision.
• Fabrication and testing of a 3 × 2 Braille cell using six developed actuators.

Main Results:

• Experimental testing confirmed significant strains (up to 4%) and blocking forces (1 N) at moderate electric fields (100 MV m⁻¹).
• Successful integration of 17 individual actuators into a novel 3 × 2 Braille cell design.

Conclusions:

• Core-free tubular actuators made from P(VDF-TrFE-CFE) terpolymer are effective for Braille display pin actuation.
• The developed Braille cell demonstrates the practical application of these advanced actuators, paving the way for improved accessibility devices.