Open AccessAnalog-controlled light microshutters based on electrothermal actuation for smart windows
Author(s) -
Lei Xiao,
Yingtao Ding,
Peng Wang,
Huikai Xie
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.405142
Subject(s) - bimorph , materials science , optics , optoelectronics , surface micromachining , cantilever , microelectromechanical systems , voltage , actuator , light intensity , computer science , piezoelectricity , electrical engineering , fabrication , composite material , medicine , physics , alternative medicine , pathology , engineering , artificial intelligence
Smart windows for sunlight control play an important role in modern green buildings. Electrically-controllable light microshutters provide a promising solution for smart windows. However, most of reported microshutters work under on/off binary mode. In this work, an electrothermally actuated microshutter that can achieve analog light control is proposed. The microshutter consists of an array of electrothermal Al/SiO 2 bimorph cantilever plates suspended over a through-silicon cavity. The device is fabricated by a combination of surface- and bulk- micromachining processes. Test experiments show that for a single microshutter pixel, the device opening ratio can be tuned continuously from 78.6% (Open state, 0 V) all the way down to nearly 0% (Close state, 8 V) with a small hysteresis. For the entire array of 2 × 5 microshutters, the light transmission ratio varies continuously from 63.3% to 3.6% when the applied voltage is increased from 0 to 7.3 V. Furthermore, the response time, long-term reliability and window-like function of the microshutter are tested.