Interferometric apparatus with computer-generated hologram for measuring non-spherical surfaces
US9234741B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 2014 |
| Grant date | Jan 12, 2016 |
| Priority date | — |
| Expiry date | Jul 5, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/0271
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method and system of interferometrically measuring, in reflection, a non-spherical surface with two diffracted beams (of different diffraction orders) formed by a diffractive element positioned transversely to the axis of a common-path interferometer. The first diffracted beam substantially maintains the wavefront of a beam incident onto the diffractive element, while the second diffracted beam has a wavefront profile corresponding to the profile of the measured surface. The first diffracted beam may be reflected by the surface in a cat's eye configuration, while the second diffracted beam is reflected by the surface in a confocal configuration. The surface being measured can be modified to substantially balance radiant powers of the first and second diffracted beams upon reflection off the surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.