Scan error correction in low coherence scanning interferometry
US8004688B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 24, 2009 |
| Grant date | Aug 23, 2011 |
| Priority date | — |
| Expiry date | Jul 24, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49002
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In general, in one aspect, the invention features apparatus that includes a broadband scanning interferometry system including interferometer optics for combining test light from a test object with reference light from a reference object to form an interference pattern on a detector, wherein the test and reference light are derived from a common light source. The interferometry system further includes a scanning stage configured to scan an optical path difference (OPD) between the test and reference light from the common source to the detector and a detector system including the detector for recording the interference pattern for each of a series of OPD increments, wherein the frequency of each OPD increment defines a frame rate. The interferometer optics are configured to produce at least two monitor interferometry signals each indicative of changes in the OPD as the OPD is scanned, wherein the detector system is further configured to record the monitor interferometry signals. The apparatus also includes an electronic processor electronically coupled to the detection system and scanning stage and configured to determine information about the OPD increments with sensitivity to pert…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.