US3734619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method utilizing brewster angle for determining angular velocity and light beam incidence angles
Assignee: United States Department of the Air Force
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Filing: 1971-08-10
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Granted: 1973-05-22
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Expires: 1991-08-10
Abstract
Abstract A light beam linearly polarized in its plane of incidence is projected onto the peripheral surface of a rotably refracting disc at an angle that effects absorption of all the incident light. Means for detecting reflected light are positioned proximate to the point of incidence. Angular velocity of the disc is determined by the amount of change in angle of incidence of the light beam required to eliminate any light reflected due to disc movement. Change in angle of incidence of the light beam is measured by rotating the disc to a speed that eliminates any light reflected due to such change in angle of incidence.
Inventors
- 👤 R Newburgh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:55
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/36
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
138 words
The method of measuring angular velocity of a rotatable member comprising the steps of: mounting a disc member of refractory material on said rotatable member, projecting a light beam that is linearly polarized in its plane of incidence onto the peripheral surface of said disc member at an angle theta 1, whose tangent equals the relative index of refraction of the refractory material, rotating said rotatable member, detecting light reflected from said disc member, changing the angle of incidence of said light beam to an angle theta 2 at which light is no longer reflected from said disc member, and converting the change in angle of incidence of said light beam into an angular velocity measurement of said rotatable member in accordance with the relationship tan theta 2 y tan theta 1 (1 + V/C sin theta 1).
Claim 2
Independent Claim
138 words
The method of measuring angular velocity of a rotatable member comprising the steps of: mounting a disc member of refractory material on said rotatable member, projecting a light beam that is linearly polarized in its plane of incidence onto the peripheral surface of said disc member at an angle theta 1, whose tangent equals the relative index of refraction of the refractory material, rotating said rotatable member, detecting light reflected from said disc member, changing the angle of incidence of said light beam to an angle theta 2 at which light is no longer reflected from said disc member, and converting the change in angle of incidence of said light beam into an angular velocity measurement of said rotatable member in accordance with the relationship tan theta 2 y tan theta 1 (1 + V/C sin theta 1).
References Cited (Backward Citations)
US3355980A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-21 | 1976-11-20 | 1977-05-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-21 | 1980-11-20 | 1981-05-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-21 | 1984-11-20 | 1985-05-22 | $7700.00 | Window Closed / Lapsed |