Patent ID: 6883371
Filing Date: 2005-04-26
Classification: G01N

Abstract:
1. A humidity sensor for measuring the humidity of an atmosphere to which the humidity sensor is exposed comprising: an insulating substrate; and a lower electrode, a moisture sensitive layer and an upper electrode successively formed on the insulating substrate, said moisture sensitive layer having an electrical resistance which changes with a change in humidity and said humidity sensor providing a measurement of humidity based on the electrical resistance of said moisture sensitive layer, wherein the lower electrode comprises a noble metal porous body, the upper electrode comprises a noble metal porous body, the moisture sensitive layer is porous, and the upper electrode is joined to the moisture sensitive layer and a portion of the insulating substrate, and wherein a size of pores in the upper electrode is 0.5-20 μm, a size of pores in the lower electrode is 0.5-20 μm, a size of pores in the moisture sensitive layer is 0.05-0.2 μm, particles of ceramic are incorporated in an amount of 1-20 wt % into the upper electrode, particles of ceramic are incorporated in an amount of 1-20 wt % into the lower electrode, and one or both of the lower electrode and the upper electrode predominantly contains Pt.