Microsensor for measuring the position of liquids in capillaries

US6748804B1 · kind B1 · utility

Assignee

• Fraunhofer-Gesellschaft zur förderung der angewandten Forschung e.V. · DE

Inventors

• Thomas Lisec · Itzehoe, DE
• Bernd Wagner · Looft, DE
• Hans-Joachim Quenzer · Berlin, DE

Key dates

• Filing date: Jul 22, 2002
• Grant date: Jun 15, 2004
• Expiry date: Jul 22, 2022

Classification

• Technology area (CPC G): Physics
• CPC primary: G01F23/242
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A sensor element for electrically measuring the position of liquid levels, comprising a substrate (2) and a plurality of electrodes (3) that can be contacted individually and that are mounted on the substrate, characterized in that the electrodes comprise sensor-active partial electrodes (5) that are networked with electrical connections (7), with the partial electrodes of two respective electrodes always being positioned opposite one another, separated by a distance, as partial electrode pairs (11) and with the electrode pairs (8) thus formed recurring periodically over the length of the sensor. Quasi-digital measuring methods are derived from the behavior of the impedance of the electrode pairs, whereby the liquid level is measured by detecting a conductivity boundary in a capillary filling.