Tactile device based on opto-mechanical actuation of liquid crystal elastomers

• A refreshable tactile system based on the opto-mechanical properties of nematic elastomer actuators is presented.
• The actuator components were described to better understand the device operation.
• Full characterization of single actuators was carried out. Parameters such as force, time response and the displacement of single pins were measured.
• Communication software and specific hardware were developed to control the operation of the device.
• Dynamic cyclic tests were performed to optimize the operational parameters of the whole system.

Nematic elastomers are promising materials for the fabrication of actuators due to their ability to reversibly contract and expand during phase transitions triggered by external stimuli. Thus, actuation can be produced on demand, forcing these phase changes. Here, we present a refreshable tactile device based on the opto-mechanical properties of liquid crystalline elastomers (LCE) with the capability to represent Braille characters and simplified graphical information. The actuators designed are based on the use of the stress gradient generated in the elastomer under illumination to exert a force on movable components. Additionally, hardware implementation and a communication software interface were developed to provide end users with a complete solution. Displacements of 0.8 mm with measured forces of up to 40 mN were reached without material degradation, proving not only the viability of the device but also the potential applications of this type of actuator.