INTERFERENCE-OPTICAL FORCE SENSOR FOR SMALL FORCES

Gerd Jäger, Roland Füßl

Abstract

Force measurement at a resolution in the micronewton range is advantageously performed by means of electromagnetic force compensation. So far, weighing systems of this kind have been working only in a horizontal position. Although resistance
strain gauge force sensors are suited to various force directions, they cannot be used for precision measurements in the micronewton range. <br />
In this paper, an interference-optical force (IOF) sensor is described which can be used both for horizontal and vertical force measurement. The force measuring range of a specially designed force sensor amounts to 100 mN (10 g), resolution to 0.01 mN, and the extended measuring uncertainty to 0.008 mN for k = 2. The structure, the operating principle and the signal
processing of the force sensor are described and, furthermore, a uncertainty of measurement analysis of the entire system is made. The successful application of the interference-optical force sensor is finally demonstrated by means of the example of the calibration of applanation tonometers.

Keywords

force measurement, laser interferometer, horizontal force measurement

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PWC-2003-TC3-003.pdf

DOI

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IMEKO TC

TC3 - Measurement of Force, Mass, Torque, and Gravity

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