Interferometer with catadioptric imaging system having expanded range of numerical aperture
US5757493A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 16, 1996 |
| Grant date | May 26, 1998 |
| Priority date | — |
| Expiry date | Oct 16, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/255
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A catadioptric imaging system for an interferometer includes a beamsplitter plate for reflecting a beam of light to a concave mirror for transmitting reflected light from the mirror. The beamsplitter reflections and transmissions produce opposite sign spherical aberrations. A refractive optic is located between the beamsplitter plate and a convex test surface for removing residual spherical aberrations and for permitting more variability in the positioning of the beamsplitter plate. Design variables for both the refractive optic and the position of the beamsplitter plate can be used to adjust a numerical aperture of the beam approaching the test surface. The refractive optic can also be used as a Fizeau objective to further reduce errors in the imaging system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.