Flexible haptic display with 768 independently controllable shape memory polymers taxels

We report the first high-resolution flexible haptic display with 768 (32x24) individually addressable taxels (tactile pixels) designed for wearables and virtual reality (VR) applications. The device integrates a thin Shape Memory Polymer (SMP) membrane with a matrix of compliant carbon-silicone composite heaters, a 4-layer flexible PCB and a flexible fluidic chamber. The actuator yield is 99 %, the taxel pitch is 4 mm and the average displacement is 275 μm with a 225 mN holding force, allowing easy discrimination using the sense of fine touch. One line can be reconfigured and latched in 2.5 s; the entire array can be refreshed in under 1 min 30 s with our current drive circuit. The bistable nature of SMPs enables selective and independent actuator motion by judiciously synchronizing their local Joule heating with a global external pressure supply.