Method and device for noncontacting self-referencing measurement of surface curvature and profile
US5067817A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 8, 1990 |
| Grant date | Nov 26, 1991 |
| Priority date | — |
| Expiry date | Feb 8, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/24
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Measurement of curvature and profile of a reflective test surface by simultaneous measurement of slope at two closely spaced points on the test surface. A pair of parallel, nearly collimated light beams, which are slightly displaced relative to each other and of opposite linear polarization, and which intersect the test surface are reflected by the test surface, separated by a polarizing beam splitter and focused onto individual position sensitive detectors, which sense the slopes of the test surface at the points where it is intersected by the beams. The difference between the measured slopes is proportional to the local curvature. The device can be scanned along the surface to give a profile of measured curvature values, which are twice integrated to give the surface profile, although measurement at a single point without any such processing yields the test piece curvature. The device is reconfigured to test surfaces with different curvatures by virtue of one of the detectors being movable during initial alignment, and by virtue of a steering mirror and associated servo control system which maintain an essentially constant angle of incidence on the test surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.