MEMS piezoelectric resonant dew point sensor device and dew point identification method thereof

Abstract

The invention discloses an MEMS piezoelectric resonant dew point sensor device and a dew point identification method thereof, and the method comprises the steps: driving an MEMS piezoelectric resonator through a network analyzer, introducing to-be-detected gas into a gas chamber through a gas inlet hole, and achieving the sealing of the gas chamber; powering the semiconductor chilling plate on for cooling, increasing the relative humidity in the air chamber continuously until water vapor is saturated, generating moisture condensation on the surface of the MEMS piezoelectric resonator, and recording the temperature value of the temperature sensor and the resonant frequency value output by the MEMS piezoelectric resonator continuously; and S2, performing piecewise function fitting by taking the resonant frequency value output in the cooling process in the step S2 as a dependent variable y and the negative temperature value as an independent variable x, wherein in the final function obtained through fitting, the temperature value of the temperature sensor corresponding to the segment point is the dew point temperature of the to-be-detected gas. According to the method, the range of types of MEMS resonators which can be used in the field of dew point measurement is widened, and the reliability and the precision of measurement are also improved.

Description

technical field [0001] The invention relates to the technical fields of microelectromechanical systems (MEMS) and humidity measurement, in particular to a MEMS piezoelectric resonance dew point sensor device and a dew point identification method thereof. Background technique [0002] Humidity sensors play an important role in natural gas supply, semiconductor manufacturing, aerospace, biomedicine and other fields. The measurement of dew point temperature is internationally recognized as the most accurate humidity measurement method. Humidity generally has two expressions: absolute humidity and relative humidity. Absolute humidity refers to the actual moisture content of the air, while relative humidity refers to the ratio of the actual moisture content of the air to the theoretical maximum moisture content. [0003] The dew point temperature is absolute humidity and is not affected by ambient temperature and atmospheric pressure. The dew point temperature is the temperatu...

AI Technical Summary

Problems solved by technology

The first is the negative temperature-frequency characteristic (TCF) of piezoelectric materials, that is, lowering the temperature will cause the resonant frequency of the MEMS piezoelectric resonator to increase

There is also a characteristic that cooling in the gas chamber will lead to an increase in relative humidity, which will hinder the vibration of the MEMS piezoelectric resonator and reduce the resonance frequency

The last is the mass load effect of the resonator. After the temperature drops to the dew point temperature, the resonator surface will condense and the mass will increase, resulting in a decrease in the resonance frequency.

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