Chromatic point sensor compensation including workpiece material effects
US8587789B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 2011 |
| Grant date | Nov 19, 2013 |
| Priority date | — |
| Expiry date | Jun 4, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2210/50
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of error compensation in a chromatic point sensor (CPS) reduces errors associated with varying workpiece spectral reflectivity. The errors are associated with a distance-independent profile component of the CPS measurement signals. Workpiece spectral reflectivity may be characterized using known spectral reflectivity for a workpiece material, or by measuring the workpiece spectral reflectivity using the CPS system. CPS spectral reflectivity measurement may comprise scanning the CPS optical pen to a plurality of distances relative to a workpiece surface and determining a distance-independent composite spectral profile from a plurality of resulting wavelength peaks. By comparing the distance-independent composite spectral profile obtained from a workpiece with that corresponding to the CPS distance calibration procedure, the contribution of the reflectivity characteristics of the workpiece will be indicated in the differences between the profiles, and potential CPS position errors due to varying workpiece reflectivity characteristics may be calculated and/or compensated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.