Micro-grating tilt sensor with self-calibration and direct intensity modulation

A micro-grating tilt sensor based on phase diffraction grating with self-calibration capability and direct intensity modulation is proposed. The optical tilt sensor consists of a coherent light source, gold gratings patterned on the transparent substrate, a silicon proof mass supported by the eight symmetrical Al cantilevers. Al membrane is sputtered on the bottom of the proof mass. Both Au and Al membrane serve as electrodes for electrostatic actuation. This can provide the sensitivity adjustment and self-calibration capabilities. Experiments show that the inclinometer provides the maximum incline sensitivity of 90 mV/°, resolution of 0.00006°, a measurement range of ± 5° in the rotational plane that is parallel to the direction of the gravity, and good self-calibration ability with electrostatic actuation.