Apparatus for measuring angular and linear displacements
US4247769A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1978 |
| Grant date | Jan 27, 1981 |
| Priority date | — |
| Expiry date | Dec 21, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01D5/38
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical apparatus for measuring angular or linear displacements. The apparatus comprises a single planar element having on its surface a pattern of sectors characterized by alternating optical transmission coefficients. An optical system superimposes a real image of a portion of the pattern upon that portion of the pattern itself. This image moves in the direction opposite to the planar element, so that as the element moves, the interaction of the sectors of the image with the sectors themselves creates alternating light and dark areas as a result of shuttering or interference effects. A light sensor monitors these light and dark areas thereby providing a measure of the displacement of the planar element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.