Method and apparatus for automated focusing of an interferometric optical system
US5208451A · kind A · utility
14Cited by
3References
38Claims
0Family size
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Inventor
Key dates
| Filing date | May 4, 1992 |
| Grant date | May 4, 1993 |
| Priority date | — |
| Expiry date | May 4, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/244
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for removing the deleterious effects of interference on the focus error signal when focusing interferometric optical systems using triangulation or astigmatic techniques. These interference effects are eliminated by using the phase relationship between the differential error signal and the total intensity of the beam incident on the differential detector to identify and recover a unique focus position of a surface under test.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.