An Electrothermally Actuated Microshutter Array With Enhanced Power Efficiency for Intelligent Lighting Control

With the rapid development of smart vehicles and unmanned driving, intelligent lighting control systems that can generate programmable illumination patterns are attracting great attention. In this work, an electrothermally actuated rolling shutter array is proposed to realize intelligent automobile headlights. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 8$ </tex-math></inline-formula> array of electrothermal microshutters is designed and fabricated. The chip size is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$26\times 26\times 0.5$ </tex-math></inline-formula> mm with an effective optical aperture of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$20\times 20$ </tex-math></inline-formula> mm. Resistive heaters on rolling shutters are designed with a new proposed method for a uniform temperature distribution. In order to improve power efficiency, polyimide (PI) filled trenches are implemented to increase thermal isolation, reducing both the operating voltage and the power consumption. Experimental results show that the opening ratio of a single microshutter pixel changes from 71% at 0 V (Open-state) to 2.6% at 2.8 V (Close-state). The open-to-close switching power efficiency is 9.1 mW/mm2, corresponding to a maximum power consumption of 3.65 W for the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 8$ </tex-math></inline-formula> microshutter array in Close-state. Furthermore, a mimicked traffic scene has been successfully demonstrated, where the microshutter array provides programmable illumination for a model car.