Three-ports micro ER valve for ER suspension fabricated by photolithography

A three-ports micro ER valve has been fabricated by photolithography, which is made of a patterned resist film between two-glass plates coated ITO electrode pattern. And one inlet channel (height h=0.1 mm, width w=2mm) of the ER suspension diverges into two outlet channels having ER valves, so that the inflow of the ER suspension from the inlet port is divided into two outflows to the two outlet ports by synchronously controlling a pair of ER valves installed in the outlet channels. The PWM control strategy is applied to a pair of ER valves to change the flow rates, as proposed in our previous paper. The PWM control of each outlet micro ER valve can realize the almost same changing characteristics of flow rate with the duty ratio as that of a conventional valve. The switching characteristics of a pair of ER valves have been investigated by measuring the flow rates from both outlet ports and visualizing the micro-flow behavior of ER suspension in the ER valves.