Method and device for the measurement of force by a fiber optics system by evaluating phase shift of light waves
US5308973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1991 |
| Grant date | May 3, 1994 |
| Priority date | — |
| Expiry date | Nov 21, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L1/243
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and the device for fiber-optic measurement of the absolute value of the pretensioning in a highly loaded mechanical structural component part are based on the measurement of the phase displacement of a light wave caused by the strain-induced birefringence in a single-mode light waveguide 4 which is embedded between two metallic disks or washers 3a, 3b. Since the measurement results are ambiguous modulo-2.pi., serial or simultaneous measurement with two light wavelengths .lambda..sub.1, .lambda..sub.2 is used according to a first method variant of the invention. The quantity of 2.pi. periods can be unequivocally determined within a predetermined measuring range by means of comparing the two measurement results. The evaluation is preferably effected according to a quadrature or phase step method, known per se. According to second method variant, the light waveguide 4 is irradiated with polarized white light. The phase difference of the two linear modes due to the influence of force on the structural component part is compensated for in a compensation device 20. The control signal required for the compensation of the path difference is evaluated as a measurement for the force…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.