US3672777A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for sensing a change in light intensity
Assignee: Societe dOptique Precision Electronique et Mecanique SOPELEM SA
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Filing: 1970-09-21
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Granted: 1972-06-27
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Expires: 1990-09-21
Abstract
Abstract A REFRACTOMETER IN WHICH THE POSITION OF THE CHANGE IN INTENSITY OF THE REFRACTOMETER BEAM AT THE CRITICAL ANGLE IS SENSED BY A PHOTOELECTRIC SENSOR COMPRISING AN OPAQUE SCREEN DEFINING TWO OR THREE SLITS BEHIND EACH OF WHICH A PHOTOELECTRIC CELL IS POSITIONED, THE OUTPUTS OF THE CELLS BEING SUPPLIED TO AN ELECTRONIC CIRCUIT WHICH PROVIDES A SIGNAL AT THE MEANS POSITION OF THE CHANGE IN INTENSITY.
Inventors
- 👤 Helenio Llop
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:58
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/43
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |