Smartphone Compatible Semitransparent Microfluidic-Based Refreshable Braille System

This article presents a refreshable microfluidic Braille display system fabricated from polydimethylsiloxane (PDMS), offering a transparent, low-cost, and fast-response haptic interface. The device architecture adheres to the standardized Braille dot configuration, wherein characters are generated via fluidic-driven inflation of elastomeric membranes. To reduce fluidic and control complexity, the system is designed to display an identical Braille character across all cells simultaneously; the visually impaired reader nonetheless perceives different letters as a function of fingertip position, even though a single character is rendered repeatedly over the entire display area. Circuit-level modeling of a four-cell prototype is presented, and the capability to render a three-letter word in conjunction with integrated finger-tracking functionality is experimentally demonstrated. The transient membrane response is characterized and compared with analytical predictions, confirming that the refresh rate exceeds typical finger-scanning speeds of visually impaired users. Owing to its optical transparency, the proposed system can be integrated with smartphones or tablets, thereby enabling simultaneous access to identical digital content by both sighted and visually impaired users.