Waveguide based parallel multi-phaseshift interferometry for high speed metrology, optical inspection, and non-contact sensing
US6687008B1 · kind B1 · utility
52Cited by
47References
7Claims
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Key dates
| Filing date | Oct 19, 2000 |
| Grant date | Feb 3, 2004 |
| Priority date | — |
| Expiry date | Apr 29, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/02081
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interferometer that contains a tri-coupler to mix light from three different waveguides. The light is emitted from a light source and may be reflected from a test surface. The output of the tri-coupler may be three different light beams that have intensities 120 degrees out of phase from each other. The out-of-phase light beams may be detected by a plurality of photodetectors. The detected out-of-phase light beams may be used to determine a height of the test surface. The waveguides and tri-coupler provide a compact and relatively inexpensive interferometer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.