Method and apparatus for optically measuring absolute displacement
US7268875B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 2004 |
| Grant date | Sep 11, 2007 |
| Priority date | — |
| Expiry date | Aug 17, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/344
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus using two sets of polarized light detection systems are disclosed for optically measuring absolute displacement. In the first detection system a step motor is controlled to drive an analyzer to trace synchronously the displacement being measured by comparison of the magnitude of the intensity of two orthogonal light beams and then the number of control pulses from the step motor becomes a value of the displacement measured; and by comparison with the magnitude the intensity of a plurality of light beams with phase difference from a plurality of light paths in the second polarized light detection system the section of system operation is ascertain and consequently the absolute displacement is detected and measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.