Optically interrogated MEMS pressure sensor array

Abstract

A novel pressure measurement technique is developed with the objective to simplify wind tunnel investigations while providing full field measurement capability with highest measurement performance. The static pressure distributions are recorded by interferometric means using an array of silicon diaphragm microresonators as pressure sensing elements. They are remotely excited into free vibration using a capacitive ultrasound transducer (CUT) transmitting high power narrow band (50 -80kHz) acoustic noise. Dependent on their quasi-static deflection caused by a pressure load the resonance frequency varies with an average pressure sensitivity of 3Hz/Pa at 70kHz. Further requirements for the system performance are a maximum pressure, temporal and spatial resolution of 0.2% of FS (10kPa), 1Hz and 5mm, respectively.

Packaging Technology for an Implantable Inner Ear MEMS Microphone

“…The acoustic receiver was built on the basis of a MEMS CMIC (ADMP504, Analog Devices, Inc., Norwood, MA, USA) that was sealed using a single-crystal silicon (SCS) diaphragm available from a former project [30] (Figure 6). The square SCS diaphragm was 1.8 mm large, 7 μm thick and suspended on a 4.5 mm large and 0.4 mm high SCS support.…”

Mechanical characterization of MEMS bi-stable buckled diaphragms.

“…The two share the dimensions and stress and show repeatability in device fabrication. The theoretical model is completely directionally independent and predicts the same actuation pressure regardless of direction, equation (6). Theory also predicts from equation (5) the arrays, the dies with only two diaphragms behave in the same fashion; the smaller diaphragms actuate at a larger vacuum pressure and the up mode does so at a lower value than the down mode, see Figure 36 and Figure 37 for a direct comparison.…”

“…These devices can be used for a multitude of applications, including zero-power pressure sensors [1], large displacement actuators [2], BIO-MEMS to measure pressures within a human body [3]. Remote pressure sensors that can be read using light, such as a Bragg grating, allowing for many more applications in harsher environments [4][5][6]. Diaphragms that operate in a large deflection regime, involving the stability of buckled structures, offer many potential performance benefits, but also present greater challenges in prediction of behavior.…”