Reconfigurable Braille display with phase change locking

Abstract

Automatically updated signs and displays for sighted people are common in today's world. However, there is no cheap, low power equivalent available for the blind. This work demonstrates a reconfigurable Braille cell using the solid-to-liquid phase change of a low melting point alloy as a zero holding power locking mechanism. The device is actuated with the alloy in the liquid state, and is then allowed to solidify to lock the Braille dot in the actuated position. A low-cost manufacturing process is developed that includes molding of a rigid silicone to create pneumatic channels, and bonding of a thin membrane of a softer silicone on the surface for actuation. A plug of Field's metal (melting point 62 °C) is placed in the pneumatic channels below each Braille dot to create the final device. The device is well suited for low duty cycle operation in applications such as signs, and is able to maintain its state indefinitely without additional power input. The display requires a pneumatic pressure of only 24 kPa for actuation, and reconfiguration has been demonstrated in less than a minute and a half.

Electropneumotactile Stimulation: Multimodal Haptic Actuators Enabled by a Stretchable Conductive Polymer on Inflatable Pockets

“…For example, Soule and Lazarus demonstrated a pneumatic Braille array whose configuration could be locked into place by filling the pockets with low‐melting‐point alloys. [ 9 ] In another example, Besse et al achieved a similar result in a 32 × 24 array using a shape‐memory polymer. Individual pixels were softened using stretchable heaters prior to inflation.…”

“…[ 8 ] For example, they can be arranged into pixelated arrays for reconfigurable Braille displays. [ 9,10 ] While pneumatic actuators typically comprise an air pocket in an elastomer, [ 9,11 ] the use of other materials and components can add functionality, such as the ability to “lock” the pixels into place. For example, Soule and Lazarus demonstrated a pneumatic Braille array whose configuration could be locked into place by filling the pockets with low‐melting‐point alloys.…”

Organic Haptics: Intersection of Materials Chemistry and Tactile Perception

“…[40][41][42][43] Haptic technologies [1] have historically been dominated by devices based on mechanical actuation of motors. [44][45][46] The most sophisticated haptic devices available use some combination of motors, electrical signals (e.g., the Teslasuit), [47] hydraulic or pneumatic actuators, [48] ultrasonics, [7] or manipulation of temperature. [49,50] "Surface haptics" is a subfield whose goal is to control the feeling of an object's surface (e.g., of the screen of a smartphone or tablet, Fig.…”

Dynamic braille display based on surface-structured PVC gel

“…Dynamic braille displays are devices that display dynamic braille for the visually impaired, actuated by an array of micro-actuators. Until now, researchers have provided some actuating schemes for dynamic braille displays, including electromagnetic actuators [1,2], pneumatic actuators [3][4][5][6][7], microliter combustion actuators [8], piezoelectric actuators [9][10][11][12], PVDF [13], IPMC [14], dielectric elastomers [15], * Author to whom any correspondence should be addressed.…”