Method of and system for measurement of direction of surface and refractive index variations using interference fringes
US5557408A · kind A · utility
10Cited by
3References
6Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 17, 1995 |
| Grant date | Sep 17, 1996 |
| Priority date | — |
| Expiry date | Mar 17, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A main measuring light having a first wavelength is projected onto a work and a reference surface to produce first interference fringes and a determination light having a second wavelength slightly different from the first wavelength is projected onto the work and the reference surface to produce second interference fringes. Whether the surface of the work is concave or convex, in which direction the surface inclines or the refractive index distribution of the work is determined on the basis of the relative positions of the first and second interference fringes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.