High performance microshutter device with space-division modulation

Abstract

This paper presents a microshutter device with space-division modulation for high brightness and improved grayscale level. High brightness is achieved with a large aperture that originates from out-of-plane movement with a large deflection, and space-division modulation improves the grayscale level by overcoming the operating speed limitation of digital modulation. The proposed microshutter device has multiple microshutters consisting of a single pixel, and the grayscale level is modulated by the number of actuated microshutters. We adopted a novel electrostatic actuation method in which the number of actuated microshutters is proportional to the applied analog voltage level. The actuation method was verified theoretically by means of an equivalent electrical circuit model. Furthermore, to test the proposed actuation method, we fabricated quarter-circle curl-shaped microshutters and demonstrated the proposed microshutter device with a control signal of 20 V to 33 V. The switching time is 20 mu s from the open state to the closed state, and the lifetime is estimated to be 500 billion cycles.