Method and apparatus for measuring opposite surfaces
US6633387B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 2000 |
| Grant date | Oct 14, 2003 |
| Priority date | — |
| Expiry date | Feb 5, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interference optical system (18) leads parallel beam to a pair of opposed test surface (M1, M2). It then leads, from the test surfaces via different optical paths (C1, C2), interference fringe images formed by radiation of the parallel beam to the test surfaces (M1, M2), respectively. The interference optical system (18) has a pair of opposite reference surfaces (S1, S2) formed thereon and defined with a highly accuracy parallelism and distance. A measurement head (27) is provided with these reference surfaces (S1, S2), which are interposed between and oppose to the test surfaces (M1, M2), respectively. Imaging devices (19a, 20a) take interference fringe images that are created through interference between a light reflected at each of the test surfaces (M1, M2) and a light reflected at the corresponding reference surface (S1, S2) opposing thereto.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.