Automated re-focusing of interferometric reference mirror
US9234814B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 2013 |
| Grant date | Jan 12, 2016 |
| Priority date | — |
| Expiry date | Dec 20, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A reference surface is used to develop an empirical plot between a parameter of interest, such as roughness or modulation, and the position of the reference mirror in an interferometer by repeating measurements of the reference surface at different positions of the reference mirror so as to identify the in-focus position of the reference mirror. Serial quality-control measurements of samples of interest are carried out with the reference mirror in such in-focus position until a predetermined quality-control event triggers an automated system re-calibration by re-measuring the reference surface and, if the result does not correspond to the in-focus position of the reference mirror according to the plot, by finding a new in-focus position for the reference mirror using the same plot or, alternatively, a new similarly produced plot. Sample measurements are then resumed with the mirror placed at that new position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.