A 2D Refreshable Braille Display Based on a Stiffness Variable Polymer and Pneumatic Actuation.

Visual impairments limit a person's ability to process information such as obstacles, environments, reading and especially multimedia content (e.g., photographs and videos). In this work, we present the design and operating mechanism of Braille PolyPad, a prototype 2D refreshable braille display featuring 4×10 braille cells, enabling the transformation of images to 2D braille information. The Braille Polypad is based on a miniature pump enabled pneumatic actuation of Braille pins. The encoder transformed the pattern information to a heating circuits to trigger the softening of a stiffness variable polymer, allowing for large pneumatic actuation in the softened pin area. The braille pattern can switch on and off in 0.5s each regardless of the number of braille cells and pins, with low operation voltage and low power consumption. The technical features in this work could enable low-cost, large-size matrix refreshable braille displays in compact form factor. Full development of the prototype device is still ongoing, including materials optimization, actuation uniformity, and improvement of user-friendly control interface.