High-Q-value resonant-beam structure used as secondary sensitive structure

Abstract

The invention discloses a high-Q-value resonant-beam structure used as a secondary sensitive structure, and belongs to the technical field of sensors. The structure mainly includes a first resonant beam, a second resonant beam, a first support island, a second support island, a third support island, a fourth support island and a substrate. The first resonant beam and the second resonant beam are fixed to an upper surface of the substrate through the support islands of ends, and are placed side by side in parallel with spacing of certain distance. The first resonant beam and the second resonantbeam maintain self-oscillation which is perpendicular to the upper surface of the substrate, and carry out reverse vibration, energy which is transmitted by the resonant beams to the substrate through the support islands and is dissipated is offset and reduced through vibration between the two parts, and the purpose of increasing a Q value is achieved. Compared with existing lateral-vibration-sensitive structures, the structure of the invention is simple to design, reduces machining difficulty, and is high in yield.

Description

technical field [0001] The invention belongs to the field of micro-electromechanical systems, and in particular relates to a high-Q resonant beam structure as a secondary sensitive structure. Background technique [0002] The resonant pressure sensor is a typical type of resonant sensor that is sensitive to pressure changes by changing its equivalent stiffness. It has the advantages of small size, light weight, low power consumption, high measurement accuracy, good stability, easy mass production, and direct output digital , Easy computer communication and other advantages have always been the focus of research and development in various countries. For the direct sensitive mode, the pressure directly acts on the resonant sensitive structure to change its equivalent stiffness; for the indirect sensitive mode, it includes two sensitive links, namely the primary sensitive structure that directly senses the pressure and the secondary sensitive structure that indirectly senses th...

AI Technical Summary

Problems solved by technology

Since the vibration direction of the resonant beam is perpendicular to the pressure-sensitive diaphragm, there is inevitably a certain degree of energy coupling between the two; although the above two sensors have been marketed, their common problems are complex structure and high production cost , The finished product rate is relatively low, according to my country's existing micro-machining technology level, processing is very difficult

The Q value at normal pressure is 1200, and the Q value at 1kPa air pressure is 2600. The Q value of the resonator will change with the pressure environment to be measured, which is not conducive to closed-loop control and will affect the accuracy of the sensor.

The resonators and pressure-sensitive diaphragms of the three structures are all integrally produced by concentrated boron self-stop etching technology. The resonator uses lateral vibration to reduce the energy coupling with the pressure-sensitive diaphragm, but the structural layout is complex and difficult to process. larger

Although the core structures of the two sensors are simple, the vibration direction of the resonators of the two structures is perpendicular to the pressure sensitive diaphragm. Due to the energy coupling interference between the two, the improvement of the Q value of the sensor is limited to a certain extent.

Images