MEMS piston-tube based capacitive accelerometer

A MEMS capacitive accelerometer, comprising:

• a. a first base plate having a top surface and a thickness;
• b. an array of spaced apart teeth electrodes constructed in the thickness of said base plate;
• c. each said tooth electrode having a shape, a length, a height, and a thickness;
• d. said array of teeth being grouped in one or multiple sub-arrays of teeth each comprising one or more teeth, wherein the teeth in each sub-array of teeth being electrically connected to each other and electrically isolated from other sub-arrays of teeth;
• e. each sub-array of teeth being electrically addressable, whereby each sub-array of teeth forms a sensing electrode of said accelerometer;
• f. a second plate attached to said base plate and having a structure sized to fit on said base plate, said second plate having a fixed peripheral structure and a moving central structure, whereby the fixed structure being attached to the base plate and the moving central structure forms a proof mass of said accelerometer;
• g. an array of spaced apart openings constructed in the thickness of said moving structure said second plate;
• h. said array of openings sized and designed to receive and interdigitate with said array of teeth, and said array of openings with each said opening having a length, a width and a height, whereby said array of openings forms a moving electrode of said accelerometer;
• i. a plurality of spring means supports and holds said moving structure of said second plate wherein said openings are aligned with respect to said array of teeth and to return the said moving structure to its initial position in the absence of external acceleration, each said spring having a length, a thickness, and a height,
• whereby the teeth of the base plate penetrate into the openings of the top plate in response to linear acceleration along an out-of-plane axis (z-axis), or/and rotational acceleration about an in-plane axes (x and y) being measured by means of capacitance change detection that is formed between the teeth and the openings.