Method and apparatus for the rapid acquisition of data in coherence scanning interferometry
US5402234A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 1, 1993 |
| Grant date | Mar 28, 1995 |
| Priority date | — |
| Expiry date | Feb 1, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/04
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of profiling a rough surface of an object includes the steps of producing an interference pattern of the object surface using an interferometer to produce an illumination intensity on the pixels of an imaging device, varying the optical path difference between the object surface and a reference surface of the interferometer through a range including a position of zero optical path difference for each pixel, calculating values of an interference discriminator function to identify the regions of coherence, gathering at the imaging device and storing for each pixel a plurality of intensity values about the region of coherence--as identified by the state or value of the interference discriminator function calculations--at consecutive data points spaced along the range by a predetermined phase difference, storing for each pixel the relative position of the plurality of intensity values along the range, and calculating from the stored intensity values the difference in height between two selected pixels using methods known in the art. An apparatus for practicing the invention is also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.