HIMIDITY DETECTION ELEMENT

摘要

PURPOSE:To enable local cooling by a weak current in such a state that a cooling part is thermally insulated, by concentrating the cooling parts of a Peltier cooling means to the central part of a humidity detection element from which a substrate is removed. CONSTITUTION:First metal patterns 24 and second metal patterns 25 are alternately arranged to a substrate 20 and the terminal parts of both patterns are successively connected while the connection parts are arranged to the central and peripheral parts of the substrate every other one. A part, of which the reflective state is changed by the adhesion of a water droplet, is formed to the surface of the connection part group 26 of the Peltier cooling means provided to the central part of the substrate 20. The silicon nitride film provided to the central part of the back side of the substrate 20 is selectively removed by plasma etching according to photoengraving technique to form an aperture and the substrate 20 is further etched through said aperture so as to reach an insulating layer 22 to form a recessed part 21 to the substrate 20. The peltier cooling means can be also utilized as a cooling temp. detection means by changing over a connected external circuit.