Hyperfast MEMS-Based Microshutter Arrays for Laser Safety Goggles and Security Devices
摘要
An increasing number of laser attacks have been reported on bus and tram drivers, security personnel, or pilots of civil aviation during start and landing. These attacks are based on irresponsible recklessness, gross mischief, or even a terroristic background. Existing laser safety goggles have at least one or more of the following disadvantages: low transmission, not color neutral, absorbing only a few wavelengths paired with insufficient weakening, and not meeting existing norms. Our MEMS-based ultrafast microshutter arrays provide safety for all wavelengths, an optical density (OD) > 4, and a hyperfast switching speed. Microshutter arrays utilize electrostatic actuation, applying a voltage between a transparent conductive oxide electrode and a metallic microshutter grid as a counter-electrode. The actuation speed and transmission need optimization of geometry and voltage levels. The closing is initiated if hazardous laser radiation is passing a photodiode ring located around each goggle glass. In different samples, individual optimizations led to 1 μs closing time, blocking 10 W of 532 nm for >2 min, OD 4.5 in a closed state, and 75% transmission in a default state. This methodology is also able to protect security cameras against terroristic laser attacks.