Method for measuring contour variations
US7471398B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 12, 2003 |
| Grant date | Dec 30, 2008 |
| Priority date | — |
| Expiry date | Nov 30, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/45
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for measuring a contour variation of a measuring area on an object. The method includes the steps of: irradiating the measuring area with a light beam, wherein reflection or transmission of the beam occurs; splitting the transmitted or reflected beam; combining the split beams with each other and observing a fringe pattern representing a differential phase between the split beams; varying the phase of the split beams relative to each other, such that the differential phase is kept within the range of 2 pi; calculating an optical path length difference from the differential phase; and relating the optical path length difference to the contour variation of the object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.