An Electrostatic Zigzag Transmissive Microoptical Switch for MEMS Displays

This paper presents the design and characterization of the zigzag transmissive microoptical switch. It consists of a highly space-efficient zigzag electrostatic actuator and opaque shutter pair, which cover the optical channel in order to modulate a focused incident light beam. The novel zigzag design increases the electrostatic force and extends the stable travel range of the electrostatic actuator. By adjusting the dimensions of the zigzag, it can operate both under digital and analog optical switching. The real-time shutter motions have been tested by a laser-integrated microscope. Experimental data demonstrate that a zigzag electrostatic actuator of 47 mumtimes160 mum size can achieve a maximum static lateral displacement of 10 mum (18 mum total opening by a shutter pair) at 38 V. Depending on their design, zigzag devices have a mechanical resonance frequency of up to 38.6 kHz with response time less than 20 mus and lifetime above 7.6times10⁹ cycles