Patent · US Expired

Method of manufacturing a capacitive humidity sensor

US5254371A · kind A · utility

8Cited by

6References

6Claims

0Family size

Assignee

Endress u Hauser GmbH u Co. · DE

Inventors

Frank Hegner · Bad Kötzting, DE
Traugott Kallfass · Bornsteiner Straße, DE

Key dates

Filing date	Aug 28, 1991
Grant date	Oct 19, 1993
Priority date	—
Expiry date	Aug 28, 2011

Classification

Technology area (CPC G)Physics
CPC primaryG01N27/225
WIPO fieldMeasurement
WIPO sectorInstruments

Abstract

This method comprises the following steps, which are compatible with thin-film technology: forming a bottom electrode (2) on an insulating substrate (1), depositing a humidity-sensitive polymer layer (5) of uniform thickness on the bottom electrode (2) leaving contact areas (3a, 3b) uncovered, activating surface bonds of the polymer layer (5), applying a colloidal dispersion of SiO.sub.2 or Al.sub.2 O.sub.3 particles (6) of uniform grain size as a thin layer to the polymer layer (5) and subsequently drying it, depositing a cover electrode (7) on the particles (6) still evenly distributed on the polymer layer (5) after the drying of the dispersion, and removing the particles (6) together with the portions of the cover electrode (7) overlying them.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.