Discharging-phototransistor-integrated high-voltage Si photovoltaic cells for fast driving demonstration of an electrostatic MEMS actuator by wavelength modulation

In this article, the authors propose a high-voltage photovoltaic (PV) cell array integrating discharging phototransistors for the fast driving of an electrostatic MEMS actuator by light with wavelength modulation. A PV cell array and phototransistors are connected in parallel and colored with green and red lacquer, respectively. This circuit repeats the charge and discharge of a MEMS actuator by being illuminated with light whose color periodically changes between red and green. This method requires only a small additional area and can discharge the actuator at an arbitrary timing. The authors extract the parameters of the circuit and also demonstrate the dynamic driving of a MEMS comb-drive actuator.