Optical MEMS index finger microgesture input sensor for mobile and wearable devices

Abstract

We report the first optical microsystem that captures index finger microgestures with the precision, bandwidth, power consumption and form-factor required for close-range handwriting and gesture keyboarding (e.g. Swipe) on smart watches and mobile handsets. Finger position is measured with 30μm resolution (at a 5cm distance) at a bandwidth of up to 550Hz while consuming less than 15mW with the reported prototype system. A VCSEL, scanning diffractive optic element (DOE), and photodiode may be packaged in a 2×2×1mm package to fit unobtrusively in a wearable device. This component may enable the first information-rich touch-less gesture inputs to wearables.