Micromachined threshold pressure switch and method of manufacture
US5164558A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 5, 1991 |
| Grant date | Nov 17, 1992 |
| Priority date | — |
| Expiry date | Jul 5, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49105
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A pressure activated threshold switch has two electrodes separated by a small distance across a cavity. One of the electrodes is made of a mechanically compliant material. As a uniform pressure is applied to the mechanically compliant electrode, a threshold is reached at which the electrode buckles under the applied load and makes contact with the second electrode thereby closing the switch. The switch exhibits mechanical hysteresis by subsequently opening under a lower applied load. The pressure threshold switch is fabricated using wafer to wafer silicon bonding along with conventional integrated fabrication steps. The techniques of integrated circuit technologies enable dimensional control to be very good and hence activation pressures are tightly controlled. The fabrication method exploits properties of wafer to wafer silicon bonding, such as residual pressure inside sealed cavities and plastic deformation of silicon. The buckling load or threshold pressure at which the switch closes is easily tailored to specific applications. Potential applications include threshold pressure sensors for indicating when automotive tires need inflation, tank pressure monitors in air and gas comp…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.