Resonant microbeam temperature sensor

US5772322A · kind A · utility

Assignee

• Honeywell Limited · US

Inventors

• David William Burns · Minneapolis, US
• Thomas G. Stratton · Roseville, US

Key dates

• Filing date: May 31, 1996
• Grant date: Jun 30, 1998
• Expiry date: May 31, 2016

Classification

• Technology area (CPC G): Physics
• CPC primary: G01K11/26
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A temperature sensing device employs a resonant polysilicon beam, in combination with electrical circuitry for oscillating the beam at its natural resonant frequency, to sense changes in temperature. The resonant beam is formed as part of a silicon layer, and the silicon layer is in direct contact with a dissimilar material. In one version of the device, the silicon layer is deposited onto a sapphire substrate by low pressure chemical vapor deposition. In another version, the beam is part of a polysilicon layer deposited onto a silicon wafer substrate. The silicon substrate is thinned, then thermoelectrically bonded to a borosilicate glass substrate. In still another version, the silicon substrate is selectively thinned and has deposited thereon a TCE mismatched material. In all versions, temperature is sensed based on a thermal mismatch of the two dissimilar materials. The respective layers expand (and contract) at different rates in response to temperature changes, altering the level of induced axial strain in the resonant beam. The change in induced strain alters the frequency at which the beam oscillates, thereby providing a direct indication of temperature.