Apparatus for measuring a gradient of a surface
US4289400A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 7, 1980 |
| Grant date | Sep 15, 1981 |
| Priority date | — |
| Expiry date | Feb 7, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/255
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for continuously measuring a gradient of a curved surface at a number of different points thereon is disclosed in which a laser beam reflected at the point to be measured on the surface makes a beam spot on a photo sensor. The photo sensor follows the beam spot while the center of the beam spot and the center of the photo sensor coincide. The displacement between the beam spot from the point subjected to measurement and the beam spot from a reference point on the surface of the photo sensor is proportional to the gradient at the point subjected to measurement. The photo sensor is, for example, a differential type which comprises four photo diodes. The numerical control table is used to determine the positional relationship of the point to be measured with respect to the laser beam and an X-Y recorder is used to follow the beam spot.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.