US4218924A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ultrasonic ellipsometer
Assignee: Boeing North American Inc
•
Filing: 1979-07-02
•
Granted: 1980-08-26
•
Expires: 1999-07-02
Abstract
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.
Inventors
- 👤 Christopher M. Fortunko
- 👤 Carmine F. Vasile
- 👤 Robert B. Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:30
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/22; G01N29/24; G01N29/2412; G01N2291/00; G01N2291/02; G01N2291/028; G01N2291/02827; G01N2291/04; G01N2291/042; G01N2291/0421; G01N2291/0422; G01N2291/0428
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
106 words
An electromagnetic acoustic transducer for generating and detecting an elliptically polarized ultrasonic wave in an electrically conductive material, comprising: a source of magnetic flux for establishing a magnetic field directed normal to a surface of said material and periodic in intensity in a direction perpendicular to said field direction; a first conductor for inducing a first alternating current in a first current direction within said material perpendicular to said field direction and perpendicular to said periodic direction; and a second conductor for inducing a second alternating current in a second current direction within said material perpendicular to said field direction and parallel to said periodic direction.
Claim 2
Dependent Claim
106 words
An electromagnetic acoustic transducer for generating and detecting an elliptically polarized ultrasonic wave in an electrically conductive material, comprising: a source of magnetic flux for establishing a magnetic field directed normal to a surface of said material and periodic in intensity in a direction perpendicular to said field direction; a first conductor for inducing a first alternating current in a first current direction within said material perpendicular to said field direction and perpendicular to said periodic direction; and a second conductor for inducing a second alternating current in a second current direction within said material perpendicular to said field direction and parallel to said periodic direction.
Claim 3
Dependent Claim
18 words
The transducer of claim 1, wherein said source of magnetic flux comprises a row of alternately oriented magnets.
Claim 4
Dependent Claim
35 words
The transducer of claim 2, wherein: said first conductor comprises a first coil coaxially wound around said row; and said second conductor comprises a second coil wound around said row orthogonal to said first coil.
Claim 5
Dependent Claim
17 words
The transducer of claim 3, wherein said row comprises a plurality of uniformly sized, adjacent permanent magnets.
Claim 6
Dependent Claim
50 words
An electromagnetic acoustic transducer for generating and detecting an elliptically polarized ultrasonic wave in an electrically conductive material, comprising: a row of uniformly sized, adjacent, alternately oriented permanent magnets; a first coil coaxially wound around said row; and a second coil wound around said row orthogonal to said first coil.
Claim 7
Dependent Claim
50 words
An electromagnetic acoustic transducer for generating and detecting an elliptically polarized ultrasonic wave in an electrically conductive material, comprising: a row of uniformly sized, adjacent, alternately oriented permanent magnets; a first coil coaxially wound around said row; and a second coil wound around said row orthogonal to said first coil.
Claim 8
Dependent Claim
108 words
An electromagnetic acoustic transducer for generating an elliptically polarized ultrasonic wave in an electrically conductive material, comprising: means for establishing a magnetic field directed normal to a surface of the material and periodic in intensity in a direction perpendicular to said field direction; means disposed between said magnetic field means and said surface for inducing a first alternating current in a first current direction within said material perpendicular to said periodic direction; and means disposed between said magnetic field means and said surface for inducing a second alternating current in a second current direction within said material perpendicular to said field direction and parallel to said periodic direction.
Claim 9
Dependent Claim
108 words
An electromagnetic acoustic transducer for generating an elliptically polarized ultrasonic wave in an electrically conductive material, comprising: means for establishing a magnetic field directed normal to a surface of the material and periodic in intensity in a direction perpendicular to said field direction; means disposed between said magnetic field means and said surface for inducing a first alternating current in a first current direction within said material perpendicular to said periodic direction; and means disposed between said magnetic field means and said surface for inducing a second alternating current in a second current direction within said material perpendicular to said field direction and parallel to said periodic direction.
Claim 10
Dependent Claim
206 words
An ultrasonic ellipsometer, comprising: a transmitting transducer for generating an elliptically polarized ultrasonic wave in an electrically conductive material, including a first source of magnetic flux for establishing a first magnetic field directed normal to a surface of said material and periodic in intensity in a direction perpendicular to said first field direction, a first transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and perpendicular to said periodic direction, and a second transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and parallel to said periodic direction; and a receiving transducer for detecting said polarized wave in said material, including a second source of magnetic flux for establishing a second magnetic field directed normal to said surface and periodic in intensity in a direction perpendicular to said second field direction, a first receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and perpendicular to said periodic direction, and a second receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and parallel to said periodic direction.
Claim 11
Dependent Claim
206 words
An ultrasonic ellipsometer, comprising: a transmitting transducer for generating an elliptically polarized ultrasonic wave in an electrically conductive material, including a first source of magnetic flux for establishing a first magnetic field directed normal to a surface of said material and periodic in intensity in a direction perpendicular to said first field direction, a first transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and perpendicular to said periodic direction, and a second transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and parallel to said periodic direction; and a receiving transducer for detecting said polarized wave in said material, including a second source of magnetic flux for establishing a second magnetic field directed normal to said surface and periodic in intensity in a direction perpendicular to said second field direction, a first receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and perpendicular to said periodic direction, and a second receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and parallel to said periodic direction.
Claim 12
Dependent Claim
47 words
The ellipsometer of claim 7, further comprising: a high frequency signal generator for driving said transmitting transducer; and a signal splitter for coupling said generator to said first and second transmitting conductors with a variable relative amplitude and phase, thereby controlling the polarization of said generated wave.
Claim 13
Dependent Claim
26 words
The ellipsometer of claim 8, further comprising a signal analyzer connected to said first and second receiving conductors for indicating the polarity of said detected wave.
Claim 14
Dependent Claim
251 words
An ultrasonic ellipsometer, comprising: a transmitting transducer for generating an elliptically polarized ultrasonic wave in an electrically conductive material, including a first source of magnetic flux for establishing a first magnetic field directed normal to a surface of said material and periodic in intensity in a direction perpendicular to said first field direction, a first transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and perpendicular to said periodic direction, and a second transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and parallel to said periodic direction; a receiving transducer for detecting said polarized wave in said material, including a second source of magnetic flux for establishing a second magnetic field directed normal to said surface and periodic in intensity in a direction perpendicular to said second field direction, a first receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and perpendicular to said periodic direction, and a second receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and parallel to said periodic direction; a high frequency signal generator for driving said transmitting transducer; a signal splitter coupling said signal generator to said transmitting transducer for controlling the polarization of said generated wave; and a signal analyzer connected to said receiving transducer for indicating the polarity of said detected wave.
Claim 15
Dependent Claim
251 words
An ultrasonic ellipsometer, comprising: a transmitting transducer for generating an elliptically polarized ultrasonic wave in an electrically conductive material, including a first source of magnetic flux for establishing a first magnetic field directed normal to a surface of said material and periodic in intensity in a direction perpendicular to said first field direction, a first transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and perpendicular to said periodic direction, and a second transmitting conductor for inducing an alternating current in a direction within said material perpendicular to said first field direction and parallel to said periodic direction; a receiving transducer for detecting said polarized wave in said material, including a second source of magnetic flux for establishing a second magnetic field directed normal to said surface and periodic in intensity in a direction perpendicular to said second field direction, a first receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and perpendicular to said periodic direction, and a second receiving conductor for detecting an alternating current in a direction within said material perpendicular to said second field direction and parallel to said periodic direction; a high frequency signal generator for driving said transmitting transducer; a signal splitter coupling said signal generator to said transmitting transducer for controlling the polarization of said generated wave; and a signal analyzer connected to said receiving transducer for indicating the polarity of said detected wave.
Claim 16
Independent Claim
139 words
A method for generating an elliptically polarized ultrasonic shear wave in an electrically conductive material, comprising the steps of: establishing a magnetic field directed normal to a surface of the material and periodic in intensity in a direction parallel to the surface; inducing in the material and within the magnetic field a first alternating current in a first current direction perpendicular to the field direction and perpendicular to the periodic direction, the magnetic field and the first current interacting to produce a vertical shear ultrasonic wave in the material; and inducing in the material and within the magnetic field a second alternating current in a second current direction within the material perpendicular to the field direction and parallel to the periodic direction, the magnetic field and the second current interacting to produce a horizontal shear wave in the material.
Claim 17
Independent Claim
139 words
A method for generating an elliptically polarized ultrasonic shear wave in an electrically conductive material, comprising the steps of: establishing a magnetic field directed normal to a surface of the material and periodic in intensity in a direction parallel to the surface; inducing in the material and within the magnetic field a first alternating current in a first current direction perpendicular to the field direction and perpendicular to the periodic direction, the magnetic field and the first current interacting to produce a vertical shear ultrasonic wave in the material; and inducing in the material and within the magnetic field a second alternating current in a second current direction within the material perpendicular to the field direction and parallel to the periodic direction, the magnetic field and the second current interacting to produce a horizontal shear wave in the material.
Claim 18
Dependent Claim
34 words
The method of claim 11, further comprising the step of: controlling the amplitude and phase of the first alternating current relative to the second alternating current to adjust the polarization of the generated wave.
Claim 19
Dependent Claim
18 words
The method of claim 12, wherein the material is relatively thick in the direction of the magnetic field.
Claim 20
Dependent Claim
23 words
The method of claim 12, wherein the material is a bounded plate which is relatively thin in the direction of the magnetic field.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-26 | 1984-02-25 | 1984-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-26 | 1988-02-25 | 1988-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-26 | 1992-02-25 | 1992-08-26 | $7700.00 | Window Closed / Lapsed |