PURPOSE: To obtain a humidity sensor, by a method wherein the formation of a high molecular electrolyte coating layer is prepared by plasma polymerization to obtain a humidity sensitive film excellent in close adhesiveness with the surface of an electrode and the humidity sensitive film comprising a plasma polymerized polymer thin film is formed on a piezo-electric element in a closely adhered state through a thin film electrode.
CONSTITUTION: As a piezo-electric element to be used, various substances shown piezo-electric characteristics can be used and a quartz oscillator or the like is represented. As a thin film electrode, any conductive material can be used and it is pref. to use metals low in corrosiveness such as gold, silver or the like. A pair of plasma polymerized polymer thin film having hydrophilic groups introduced into the surface layers thereof is obtained by treating the surface of the polymer thin film obtained by the plasma polymerization of a monomer. A humidity sensor can be usually fabricated by a method wherein a pair of electrodes comprising a conductive material such as gold, silver or the like on both surfaces of the piezo-electric element in a closely adhered state by vapor deposition and desired plasma polymerized polymer thin films are formed on the surfaces of each electrodes in a closely adhered state by plasma polymerization using both electrodes as discharge electrodes while a hydrophilic group such as an ion exchange group is introduced into the surface layer of each polymer thin film.
TAWARA OSAMU
KOBAYASHI JIYUNYA
