Design and Testing of Flexible Contacts for Piezoelectric Hydraulic Amplified Braille Dot Display

To realize flexible output and fast response in Braille spotter contacts, in this study, a flexible contact structure of piezoelectric hydraulic amplified Braille spotter was designed. First, the structure and working principle of the piezoelectric Braille contact were designed and analyzed. Next, the mechanical model of the system was established, the expressions for the output displacement and amplification ratio of the flexible film and piezoelectric oscillator were derived, and the parameters affecting the output displacement and amplification ratio were determined. In addition, piezoelectric oscillator vibrations and the deformation of the flexible film of the hydraulic amplification structure were simulated using COMSOL Multiphysics software. Finally, the prototype was fabricated and tested experimentally. The results showed that the displacement of the flexible contact was 0.402 mm at a driving voltage and resonant frequency of 170 V and 282 Hz, respectively, and a displacement amplification of 10.1× was achieved. The response time of the piezoelectric Braille contact is less than 5 ms, which meets the requirement for application in tactile reading.