Ultrasonic ellipsometer
US4218924A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1979 |
| Grant date | Aug 26, 1980 |
| Priority date | — |
| Expiry date | Jul 2, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0428
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is an electromagnetic acoustic transducer for generating and detecting an elliptically polarized ultrasonic wave in an electrically conductive material. The transducer includes a row of uniformly sized, adjacent, alternately oriented permanent magnets, which establish a periodic magnetic field. Coaxially wound around the row is a first coil for inducing an alternating current perpendicular to the field and perpendicular to the periodic direction, while a second coil is wound around the coil orthogonal to the first coil to induce an alternating current perpendicular to the field and parallel to the periodic direction. An ultrasonic ellipsometer includes such a dual coil transmitting transducer for generating an elliptically polarized wave and a dual coil receiving transducer for detecting the wave after it has propagated through an electrically conductive medium. By using the ellipsometer to generate an elliptically polarized wave in a material and detect the change in polarization of the wave after propagating through the material, the apparatus can be employed to examine surface properties of the material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.