Fused silica high pressure sensor

Abstract

A basic pressure sensor of four fused silica discs and two defined interior cavities. The discs are bonded to one another by a cold metal film metallization. The film metallization in spaced apart discs define capacitor electrodes where a central metallization film is a common electrode and the other metallization films define separate capacitor electrodes. For a high pressure capacitance pressure sensor, end cap discs are relatively thick and are supported by an annular ring surface on interior discs which also have a small central cavity. Pressure acting on the discs develops compressive forces which change the volume of the central cavities and the capacitance as a function of pressure. For low pressure capacitance pressure sensors, the end caps are relatively thin and flex to change a capacitance relationship defined by the bonding films. A reference capacitor can be incorporated by use of an additional electrode disc.