Humidity sensor

Abstract

Abstract PURPOSE:To measure the humidity with a high sensitivity utilizing strain of a gauge due to humidity variation by forming a strain gauge resistance pattern on an elastic insulation substrate with a small hygroscopicity and an organic humidity-sensitive thin film on the pattern surface by plasma polymerization. CONSTITUTION:A strain gauge pattern 2 made of a copper nickel alloy or the like varying in the electric resistance value subject to a strain is formed on one side of an elastic insulation substrate 1 with a small hygroscopicity made of a plastic film and a connection leader 3 is mounted. Substrates 1 and 1 thus obtained are stuck togehter so as to have strain gauge resistances 2 and 2' on both sides thereof. Protective covers 4 and 4 are applied on the respective resistances 2 and 2' and then, a thin humidity sensitive film 5 is formed on one cover 4 by plasma polymerization of a nitrogen-containing monomer such as aryl amine to make a humidity sensor. The film 5 detects changes in the electric resistance of the gauge resistances 2 and 2' caused expanding according to the humidity in the atmosphere. Thus, a sensor with a better response and a higher durability is obtained.

Inventors

• 👤 Takeshi Miwa
• 👤 美和　武志

Bibliographic Details