Low-G MEMS acceleration switch
AssigneeMeggitt (Orange County), Inc.
InventorTom Kwa
Life of this patent
Estimating the term…
Abstract
A motion-sensitive low-G MEMS acceleration switch, which is a MEMS switch that closes at low-g acceleration (e.g., sensitive to no more than 10 Gs), is proposed. Specifically, the low-G MEMS acceleration switch has a base, a sensor wafer with one or more proofmasses, an open circuit that includes two fixed electrodes, and a contact plate. During acceleration, one or more of the proofmasses move towards the base and connects the two fixed electrodes together, resulting in a closing of the circuit that detects the acceleration. Sensitivity to low-G acceleration is achieved by proper dimensioning of the proofmasses and one or more springs used to support the proofmasses in the switch.
Claims16
A MEMS acceleration switch comprising:
- a base;
- a first electrode coupled to the base;
- a second electrode coupled to the base and spaced apart from the first electrode;
- an SOI wafer comprising:
- a proofmass comprising multiple layers of the SOI wafer and formed by etching into the SOI wafer around the proofmass down to a device layer, wherein the proofmass is coupled to the SOI wafer only by portions of the device layer surrounding the proofmass;
- and,
- a contact plate coupled to the SOI wafer adjacent the proofmass;
- wherein the base is coupled to and spaced apart from the SOI wafer such that the contact plate forms a gap with the first and second electrodes and the proofmass is designed to translate with respect to the SOI wafer such that the contact plate closes the gap under an acceleration and electrically connects the first and second electrodes.
A method of making a MEMS acceleration switch comprising:
- forming a base;
- coupling a first electrode to the base;
- coupling a second electrode to the base spaced apart from the first electrode;
- coupling a SOI wafer to the base;
- forming a proofmass from multiple layers of the SOI wafer by etching into the SOI wafer around the proofmass down to a device layer such that the proofmass is coupled to the surrounding SOI wafer only by portions of the device layer surrounding the proofmass;
- and,
- coupling a contact plate to the SOI wafer adjacent the proofmass;
- wherein the base is spaced apart from the SOI wafer such that the contact plate forms a gap with the first and second electrodes and the proofmass is designed to translate with respect to the surrounding SOI wafer such that the contact plate closes the gap under an acceleration and electrically connects the first and second electrodes.
Dependencies are inferred from the claim text.