Remote measurement of near-surface physical properties using optically smart surfaces
US5682236A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1993 |
| Grant date | Oct 28, 1997 |
| Priority date | — |
| Expiry date | Jul 2, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P21/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for remotely measuring such physical properties as surface temperature and strain on or near the surface of an object such as an aerodynamic model utilizes a sensor comprising a holographic diffraction grating in a thin film, formed on or affixed to the surface of the test object, thereby forming an "optically smart surface." The sensor is remotely illuminated by one or more optical address beams, which are preferably coherent laser beams. Optical beams diffracted from the surface of the sensor produce interference patterns in a remote photodetection apparatus which permits measurement in changes in grating spatial frequency caused by temperature changes or mechanical deformations of the object surface, or Doppler measurement of particle velocity in a sample volume produced by intersecting beams diffracted from the sensor hologram.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.