Patent US3811775A successfully refreshed from Google Patents.
US3811775A
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US
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Polariscope for determining stress in a transparent material
Assignee: ASG Industries Inc
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Filing: 1972-06-21
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Granted: 1974-05-21
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Expires: 1992-06-21
Abstract
Abstract A polariscope is described for detecting stresses in a transparent object. The polariscope comprises means for producing a beam of polychromatic plane polarized light, a condensing lens, an aperture, a quarter-wave retardation plate, analyzing means and a photocell. Changes in stress cause changes in the color and intensity of the light detected. Means are provided for scanning the polychromatic light beam back and forth in one direction across the transparent object that is being studied. Means are also provided for moving the transparent object in a direction transverse to the direction of the scanning light beam. The output of the photocell is applied through an amplifier to a chart recorder in order to produce a plot of the stresses in the object with respect to their position.
Inventors
- 👤 Saud M Abu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:05
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/24; G01L1/241
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
144 words
Apparatus for detecting stresses in a transparent object comprising: means for forming a beam of polychromatic plane polarized light; a lens for focusing said beam at said transparent object; a fixed quarter-wave retardation plate having such thickness as to produce quarter-wave retardation for light of a wavelength within the spectrum of light incident on it, said retardation plate being located in the beam of light from the transparent object; means for analyzing said beam of elliptically polarized light after it passes through the quarter-wave retardation plate, said means being oriented so as to pass substantially the minimum amount of light when said transparent object is unstressed; and means for supporting the means for forming the beam of polychromatic plane polarized light in constant spaced-apart relationship from the quarter-wave retardation plate and the analyzing means and for translating said supporting means across said transparent object.
Claim 2
Dependent Claim
144 words
Apparatus for detecting stresses in a transparent object comprising: means for forming a beam of polychromatic plane polarized light; a lens for focusing said beam at said transparent object; a fixed quarter-wave retardation plate having such thickness as to produce quarter-wave retardation for light of a wavelength within the spectrum of light incident on it, said retardation plate being located in the beam of light from the transparent object; means for analyzing said beam of elliptically polarized light after it passes through the quarter-wave retardation plate, said means being oriented so as to pass substantially the minimum amount of light when said transparent object is unstressed; and means for supporting the means for forming the beam of polychromatic plane polarized light in constant spaced-apart relationship from the quarter-wave retardation plate and the analyzing means and for translating said supporting means across said transparent object.
Claim 3
Dependent Claim
29 words
The apparatus of claim 1 further comprising: a photocell in the path of light passed by the analyzing means; and recording means for recording the output of the photocell.
Claim 4
Dependent Claim
35 words
The apparatus of claim 1 further comprising an opaque plate bearing a transparent aperture, said plate being located adjacent the transparent object with the aperture in the path of the beam focused by the lens.
References Cited (Backward Citations)
US3124637A
Cited
US1874217A
Cited
US3082664A
Cited
US2992589A
Cited
US3158675A
Cited
US3446977A
Cited
US3656854A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |