A thermal insulation microactuator for Braille display using paraffin wax/carbon nanotube composite with induction heating.

A new thermal insulation microactuator for Braille display using a phase change material (PCM) composite with induction heating is proposed. The PCM composite is prepared by fully mixing paraffin with multi-walled carbon nanotubes (MWCNTs), which is mainly used as both electrically and thermally conductive enhancer. As a result of that, the PCM composite is conductive and a wireless induction heating can be realized with the paraffin composite, which avoids the connection of wires from the inner chamber with a relatively simple fabrication process. In order to prevent the penetration of the paraffin from the elastic film, a solvent-resistant TPU diaphragm is adopted to seal the PCM chamber. In addition, thermal insulation between the higher temperature of PCM and the finger contact is designed by adding the PDMS diaphragm with PDMS pins. When the input power is 1.29 W at AC frequency of 1 kHz, the actuation height of the Braille dot reaches 259 μ m within 7 s. The microactuator for Braille display presented in this paper has the advantages of short response time, thermal isolation, simple fabrication, small size and low cost. [ABSTRACT FROM AUTHOR]