A novel integrable microvalve for refreshable Braille display system

We introduce a novel integrable and electrostatic microvalve for the purpose of enabling a pneumatic refreshable Braille display system (RBDS). Physical design parameters of the microvalve such as orifice size, beam length, number of beams and beam profile are experimentally explored and found promising for use with the RBDS. Particularly, one design with an orifice of 70 mum x 70 mum, beam length 665 mum, and beam count 20 is electrostatically closed against a differential pressure of 82.7 kPa with an applied voltage of 68 V-rms. Also introduced is a steady-state mechanical model of the microvalve established on coupled solution of fluid and solid domains. The model and experimental test results have been used to calculate the unknown discharge coefficient, elastic deflection, and entrance pressure. The model revealed some of the designs have remarkably low discharge coefficient and entrance pressure, implying that pressure loss occurs mostly through and around the inlet port even at fairly large supply pressures. The experimental observations concerning the practical use of the microvalve are discussed.