Humidity sensor for detecting water content in e.g. organic solvent, has resonator element and sensor layer coupled together in manner such that resonant frequency of resonator element depends on amount of water absorbed by sensor layer

摘要

The sensor (1) has a piezoacoustic resonator element (10) i.e. thin film resonator, comprising a Piezoceramic layer (13) arranged between a pair of electrode layers (11, 12). A sensor layer (14) is in direct contact with the electrode layers, and includes hygroscopic material for absorption of water, where the material has nano-tubes i.e. carbon nano-tubes. The element and the sensor layer are coupled together in a manner such that a resonant frequency of the element depends on the amount of water absorbed by the layer (14), where thickness of the layer (14) ranges about 10 to 100 nanometers. An independent claim is also included for a method for detecting water in a fluid using a humidity sensor.