Patent US4847641A successfully refreshed from Google Patents.
Patent US3797940A successfully refreshed from Google Patents.
US3797940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Refractometer with displacement measured polarimetrically
Assignee: National Research Development Corp UK
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Filing: 1971-12-08
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Granted: 1974-03-19
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Expires: 1991-12-08
Abstract
Abstract A refractometer in which a monochromatic light beam passes through a test specimen so as to be displaced, either translationally or rotationally, in dependence of the refractive index of the specimen. The beam is linearly polarised and is subjected to optical rotation through an angle depending on the extent of the displacement, the optical rotation being measured with a polarimeter to give a measure of refractive index.
Inventors
- 👤 R King
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:19
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/4133
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
187 words
A refractometer comprising: means for passing a substantially monochromatic collimated beam of light through a test specimen in such a manner that the beam is rotationally displaced from a datum position to an extent dependent on the refractive index of the specimen; means for causing the beam to be linearly polarised after its passage through the specimen; means for subjecting the polarised beam to a net optical rotation through an angle dependent on the extent of the displacement, said optical rotation means comprising means for subjecting the beam to a first optical rotation of one sense in dependence on the passage of the beam through a first wedge of optically active material disposed so that its thickness tapers in a direction transverse to and coplanar with the axes of the possible paths of the beam, and means for subjecting the beam to a second optical rotation of the opposite sense in dependence on the subsequent passage of the beam through a second wedge of optically active material geometrically similar to and similarly disposed to said first widge; and a polarimeter arranged to measure said net optical rotation.
Claim 2
Dependent Claim
187 words
A refractometer comprising: means for passing a substantially monochromatic collimated beam of light through a test specimen in such a manner that the beam is rotationally displaced from a datum position to an extent dependent on the refractive index of the specimen; means for causing the beam to be linearly polarised after its passage through the specimen; means for subjecting the polarised beam to a net optical rotation through an angle dependent on the extent of the displacement, said optical rotation means comprising means for subjecting the beam to a first optical rotation of one sense in dependence on the passage of the beam through a first wedge of optically active material disposed so that its thickness tapers in a direction transverse to and coplanar with the axes of the possible paths of the beam, and means for subjecting the beam to a second optical rotation of the opposite sense in dependence on the subsequent passage of the beam through a second wedge of optically active material geometrically similar to and similarly disposed to said first widge; and a polarimeter arranged to measure said net optical rotation.
Claim 3
Dependent Claim
144 words
A refractometer comprising: means for passing a substantially monochromatic beam of light through a test specimen in such a manner that the beam is translationally displaced from a datum position to an extent dependent on the refractive index of the specimen, means for causing the beam to be linearly polarised both before and after its passage through the specimen, a first wedge of optically active material disposed in the path of the beam with the thickness of the wedge tapering in the direction, in which the beam is displaced in passing through the specimen, and compensating wedge means disposed in the path of the polarised beam before its passage through the specimen for compensating for the variation across the width of the beam of the optical rotation resulting from the passage of the beam through said first wedge after its passage through the specimen.
Claim 4
Dependent Claim
144 words
A refractometer comprising: means for passing a substantially monochromatic beam of light through a test specimen in such a manner that the beam is translationally displaced from a datum position to an extent dependent on the refractive index of the specimen, means for causing the beam to be linearly polarised both before and after its passage through the specimen, a first wedge of optically active material disposed in the path of the beam with the thickness of the wedge tapering in the direction, in which the beam is displaced in passing through the specimen, and compensating wedge means disposed in the path of the polarised beam before its passage through the specimen for compensating for the variation across the width of the beam of the optical rotation resulting from the passage of the beam through said first wedge after its passage through the specimen.
Claim 5
Dependent Claim
174 words
A refractometer comprising: means for passing a substantially monochromatic beam of light through a test specimen twice in such a manner that the beam is displaced from a datum position to an extent dependent on the refractive index of the specimen and such that the effects of any optical activity in the specimen are in opposition for the two passages through the test specimen, means for causing the beam to be linearly polarised at least after its passage through the specimen, a first wedge of optically active material disposed in the path of the beam with the thickness of the wedge tapering in the direction in which the beam is displaced in passing through the specimen, a compensating wedge means disposed in the path of the polarised beam before its passage through the specimen for compensating for the variation across the width of the beam of the optical rotation resulting from the passage of the beam through said wedge after its passage through the specimen, and a polarimeter arranged to measure said optical rotation.
Claim 6
Dependent Claim
174 words
A refractometer comprising: means for passing a substantially monochromatic beam of light through a test specimen twice in such a manner that the beam is displaced from a datum position to an extent dependent on the refractive index of the specimen and such that the effects of any optical activity in the specimen are in opposition for the two passages through the test specimen, means for causing the beam to be linearly polarised at least after its passage through the specimen, a first wedge of optically active material disposed in the path of the beam with the thickness of the wedge tapering in the direction in which the beam is displaced in passing through the specimen, a compensating wedge means disposed in the path of the polarised beam before its passage through the specimen for compensating for the variation across the width of the beam of the optical rotation resulting from the passage of the beam through said wedge after its passage through the specimen, and a polarimeter arranged to measure said optical rotation.
References Cited (Backward Citations)
US3090222A
Cited
US3023814A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |