Capacitive micro-mechanical accelerometer

Abstract

The invention relates to a capacitive micro-mechanical accelerometer. The accelerometer comprises a substrate, a clamped frame structure, a sensitive mass block frame structure, an anchor point for fixing the clamped frame structure on the substrate, an anchor point for fixing the accelerometer sensitive mass block frame structure on the substrate, a single-degree-of-freedom elastic beam for connecting the clamped frame structure and the sensitive mass block frame structure, a single-degree-of-freedom elastic beam connected with the sensitive mass block frame structure and the anchor point, and a detection electrode unit. The detection electrode unit is composed of a non-movable electrode, the anchor point for fixing the non-movable electrode, and a movable electrode connected to the accelerometer sensitive mass block frame structure. According to the invention, the axisymmetric structure is adopted, and the movable structure anchor points are arranged on the same symmetric axis so that the performance of the accelerometer is insensitive to an environment temperature change and processing errors. The accelerometer can be widely applied to object linear acceleration detection in various fields.

Description

technical field [0001] The invention relates to a micro-machine accelerometer, in particular to a capacitive micro-machine accelerometer which is insensitive to ambient temperature changes and processing errors. Background technique [0002] Compared with traditional accelerometers, micro-mechanical accelerometers based on micro-electromechanical systems (MEMS) technology have the advantages of small size, light weight, low cost, and high reliability, and have been widely used in automotive, consumer electronics and other fields. The application requirements of high-precision micromachined accelerometers such as inertial navigation are also increasing. [0003] Capacitive micromachined accelerometers usually use a comb-tooth capacitor structure. When there is an acceleration signal in the direction of the sensitive axis, the inertial sensitive mass drives the movable comb-tooth electrode to shift, resulting in a change in the plate spacing or overlapping area of ​​the comb-...

AI Technical Summary

Problems solved by technology

Since the anchor point is the only connection between the accelerometer structure and the substrate, external thermal stress or mechanical stress will be transmitted from the anchor point to the accelerometer structure, resulting in deformation of the accelerometer structure and changes in the detection capacitance, thereby affecting the stability of the accelerometer sex

For example, the accelerometer structure between different anchor points is restricted and cannot be freely expanded and contracted. When the ambient temperature changes, thermal strain will also be generated inside the structure, which will affect the stability of the device.

Images