Rain sensor

US5789670A · kind A · utility

Assignee

• Leybold GmBH · DE

Inventors

• Michael Scherer · Crimmitschau, DE
• Roland Werner · Krefeld, DE

Key dates

• Filing date: Feb 12, 1997
• Grant date: Aug 4, 1998
• Expiry date: Feb 12, 2017

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B60S1/0892
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

In a moisture sensor (1), the effective sensor field (4) is formed by two sensor elements (8a, 8b,) having interdigitating parallel tracks. These sensor elements consist of layers of a metal nitride compound, especially a chromium-nitrogen compound, deposited by means of magnetron cathode sputtering or glow discharge onto a dielectric substrate (2), the metal nitride layers being deposited onto the substrate surface which has first been cleaned by ion sputtering. These sensor element layers (8a, 8b) have a high hardness of about 2,000 on the Vickers scale, as a result of which the sensor elements (8a, 8b) are highly resistant to abrasive wear such as that caused by windshield wipers or scratching from ice. The moisture sensor can be produced with a low electrical surface resistivity of <100 ohms.quadrature. and is chemically stable with respect to environmental effects such as salt water and/or windshield cleaning fluids. As a result, the proposed moisture sensor is especially suitable for use as a rain sensor on vehicles, the rain sensor preferably being mounted on a window of the vehicle.