Interferometric measurement of surfaces with diffractive optics at grazing incidence
US5654798A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Aug 5, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/2441
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interferometer (10) employs diffractive optics (30 and 40) for measuring errors in test surfaces (14) that differ from planes and spheres. A beam of light (28) is separated into two portions (32 and 34). One of the diffractive optics (30) can be used to reshape the second portion (34) of a beam of light (28) into a form that is different than the first portion (32) along a path of grazing incidence to the test surface (14), and the other diffractive optic (40) can be used to further reshape the second portion (34) into a form in common with the first portion (32) of the beam of light (28). The two beam portions (32 and 34) are recombined to produce an interference pattern (44) representing the errors in the test surface (14).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.