Apparatus and method for optically measuring a surface
US5311286A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 1, 1992 |
| Grant date | May 10, 1994 |
| Priority date | — |
| Expiry date | Apr 1, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/254
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus and method measures the roughness or some other surface dimension by transmitting a beam of light through a grating member at an angle of incidence relative to the grating member. The grating member has a plurality of parallel opaque bars and adjacent transparent bars. The beam of light forms a multiple line shadow pattern on the surface below the grating member formed by the shadows of the opaque bars of the grating member. A camera records the multiple line shadow pattern, and the recorded pattern is superimposed on a plurality of parallel, equally spaced scan lines oriented perpendicular to the shadow lines. The distances between the points at which adjacent shadow lines cross each respective scan line are measured to determine the roughness or some other surface dimension.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.