Patent US3902805A successfully refreshed from Google Patents.
US3902805A
Expired / Lapsed
US
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Automatic birefringence measuring apparatus
Assignee: ADAMS-RUSSELL Co INC HAVERHILL ROAD AMESBURY MA
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Filing: 1973-09-17
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Granted: 1975-09-02
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Expires: 1993-09-17
Abstract
Abstract Birefringence resulting from the relative retardation of light waves propagating at different speeds through a stressed plate or coating is measured automatically by splitting a light wave emerging from the stressed plate or coating into at least two beams, filtering each beam with a filter which transmits a different wave length, transforming the light intensity from each filter into electrical signals and using the electrical signals to measure the resulting phase shift which is directly proportional to the birefringence.
Inventors
- 👤 Salomon Redner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:03
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/21; G01N21/23
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
Apparatus for measuring birefringence, which apparatus comprises a light source, polarizer and quarter wave plates so arranged as to pass polarized light through at least a portion of a model on which birefringence is to be measured, analyzer means comprising another polarizer, means for producing periodic modulation of light intensity passing through the model, beam splitter means for dividing the light passing through the model into at least two beams, narrow pass filter means for separately filtering the light divided by the beam splitter and transmitting a different wave length through each filter, means for transforming the light intensity from each filter into electrical signals, and means for determining phase measurements between the resulting signals.
Claim 2
Dependent Claim
115 words
Apparatus for measuring birefringence, which apparatus comprises a light source, polarizer and quarter wave plates so arranged as to pass polarized light through at least a portion of a model on which birefringence is to be measured, analyzer means comprising another polarizer, means for producing periodic modulation of light intensity passing through the model, beam splitter means for dividing the light passing through the model into at least two beams, narrow pass filter means for separately filtering the light divided by the beam splitter and transmitting a different wave length through each filter, means for transforming the light intensity from each filter into electrical signals, and means for determining phase measurements between the resulting signals.
Claim 3
Dependent Claim
31 words
Apparatus for measuring birefringence as in claim 1 in which the means for producing periodic modulation of the light intensity passing through the model comprises a motor which rotates the polarizer.
Claim 4
Dependent Claim
35 words
Apparatus for measuring birefringence as in claim 1 in which the means for producing periodic modulation of the light intensity passing through the model comprises a birefringent plate modulated by periodic changes in its birefringence.
Claim 5
Dependent Claim
19 words
Apparatus for measuring birefringence as in claim 3 in which the birefringent plate is modulated by an electrical signal.
Claim 6
Dependent Claim
17 words
Apparatus for measuring birefringence as in claim 1 in which the beam splitter is a partial mirror.
Claim 7
Dependent Claim
17 words
Apparatus for measuring birefringence as in claim 1 which further includes means for displaying phase measurements obtained.
Claim 8
Dependent Claim
95 words
Apparatus for measuring birefringence, which apparatus is to be used in conjunction with a circular polariscope and comprises beam splitter means for dividing light which is passed through a birefringent member in the circular polariscope into at least two beams; means for producing periodic modulation of the light intensity passing to the beam splitter; narrow pass filter means for separately filtering light divided by the beam splitter and transmitting a different wavelength; means for transforming the light from the filter means into separate electrical signals; and means for determining phase measurements between the resulting signals.
Claim 9
Dependent Claim
95 words
Apparatus for measuring birefringence, which apparatus is to be used in conjunction with a circular polariscope and comprises beam splitter means for dividing light which is passed through a birefringent member in the circular polariscope into at least two beams; means for producing periodic modulation of the light intensity passing to the beam splitter; narrow pass filter means for separately filtering light divided by the beam splitter and transmitting a different wavelength; means for transforming the light from the filter means into separate electrical signals; and means for determining phase measurements between the resulting signals.
Claim 10
Dependent Claim
16 words
Apparatus for measuring birefringence as in claim 7 in which the polariscope is a transmission polariscope.
Claim 11
Dependent Claim
16 words
Apparatus for measuring birefringence as in claim 7 in which the polariscope is a reflection polariscope.
Claim 12
Dependent Claim
29 words
Apparatus for measuring birefringence as in claim 7 in which the means for producing periodic modulation of the light intensity is a birefringent plate modulated by an electromagnetic field.
Claim 13
Dependent Claim
106 words
Apparatus for measuring birefringence, which apparatus is to be used in conjunction with a polariscope and comprises beam splitter means for dividing the light from the analyzer of the polariscope into at least two beams, said light having passed through a specimen to be analyzed; means for producing periodic modulation of the light intensity passing to the beam splitter; narrow pass filter means for separately filtering light divided by the beam splitter and transmitting a different wave length from each filter means; means for transforming the light from each filter means into separate electrical signals; and means for determining phase measurements between the resulting electrical signals.
Claim 14
Dependent Claim
106 words
Apparatus for measuring birefringence, which apparatus is to be used in conjunction with a polariscope and comprises beam splitter means for dividing the light from the analyzer of the polariscope into at least two beams, said light having passed through a specimen to be analyzed; means for producing periodic modulation of the light intensity passing to the beam splitter; narrow pass filter means for separately filtering light divided by the beam splitter and transmitting a different wave length from each filter means; means for transforming the light from each filter means into separate electrical signals; and means for determining phase measurements between the resulting electrical signals.
Claim 15
Dependent Claim
115 words
Apparatus for measuring birefringence, which apparatus comprises a light source, polarizer and quarter wave plates so arranged as to pass polarized light through at least a portion of a model on which birefringence is to be measured, analyzer means comprising another polarizer, means for producing periodic modulation of light intensity passing through the model, beam splitter means for dividing only light passing through the model into at least two beams, narrow pass filter means for separately filtering the light divided by the beam splitter and transmitting a different wave length through each filter, means for transforming the light intensity from each filter into electrical signals, and means for determining phase measurements between the resulting signals.
Claim 16
Dependent Claim
115 words
Apparatus for measuring birefringence, which apparatus comprises a light source, polarizer and quarter wave plates so arranged as to pass polarized light through at least a portion of a model on which birefringence is to be measured, analyzer means comprising another polarizer, means for producing periodic modulation of light intensity passing through the model, beam splitter means for dividing only light passing through the model into at least two beams, narrow pass filter means for separately filtering the light divided by the beam splitter and transmitting a different wave length through each filter, means for transforming the light intensity from each filter into electrical signals, and means for determining phase measurements between the resulting signals.
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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |