Touching force response of the piezoelectric Braille cell

Abstract

Piezoelectric Braille display unit is a device that displays refreshable Braille characters for visually impaired people to read by touching. A Braille character consists of six or eight dots in a rectangular array 3x2 or 4x2. The height of the dot is controlled by a piezoelectric bimorph underneath. Electrical signals stimulate the piezoelectric bimorphs to bend up or down, consequently causing the dots to rise or fall, creating the Braille characters. In this work, design and analysis of the piezoelectric Braille cell are discussed. A field study of touching force of visually impaired people sensing the Braille characters is reported as information for material selection and design of the piezoelectric actuator in the Braille cell. The time response of the Braille cell is presented. Then, relationship between the dot height and applied voltage of the designed piezoelectric Braille cell is investigated, followed by the response of the Braille dots to the touching force. This work can serve as a useful guideline for design of piezoelectric Braille systems.