Birefringence measurement system
US6473179B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1999 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | May 24, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/23
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A practical system and method for precisely measuring low-level birefrigence properties (retardance and fast axis orientation) of optical materials (26). The system permits multiple measurements to be taken across the area of a sample to detect and graphically display (100) variations in the birefrigence properties across the sample area. In a preferred embodiment, the system incorporates a photoelastic modulator (24) for modulating polarized light that is then directed through a sample (26). The beam (“Bi”) propagating from the sample is separated into two parts, with one part (“B1”) having a polarization direction different than the polarization direction of the other beam part (“B2”). These separate beam parts are then processed as distinct channels. Detection mechanisms (32, 50) associated with each channel detect the time varying light intensity corresponding to each of the two parts of the beam. The information is combined for calculating a precise measure of the retardance induced by the sample, as well as the sample's fast axis orientation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.