US3564252A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiometer for measuring power an absolute basis
Assignee: HP Inc
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Filing: 1969-02-26
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Granted: 1971-02-16
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Expires: 1989-02-26
Abstract
Abstract There are provided two integrating spheres having the same configuration. One of the integrating spheres is heated by incident radiation collected from an outside energy source of unknown power. The second sphere is heated resistively to the same temperature attained by the first sphere. The electrical heating of the second sphere is controlled by a servo loop activated from a single detector which alternately senses thermal radiation from the two spheres. Electrical power delivered to the heating element in the second sphere is measured by a power meter and directly equals the radiative power incident in the first sphere.
Inventors
- 👤 Paul E Stoft
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:49
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/52
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
194 words
Apparatus for measuring the absolute power of unknown energy sources over a broad range of wavelengths comprising: first and second adjacently disposed thermal chamber means respectively having external surface portions for emitting thermal radiation along converging paths of travel, said first chamber means being responsive to energy received from a power source to be measured; means providing a reference source of thermal energy within said second thermal chamber means; isothermal housing means for maintaining said two thermal chamber means in a constant temperature environment; thermal radiation detector means disposed within said isothermal housing means for receiving thermal radiation along said converging paths of travel from said two thermal chamber means; means positioned between said thermal radiation detector means and said two thermal chamber means for alternately exposing said detector means to thermal radiation from said two thermal chamber means; means synchronized with said alternate exposing means and responsive to said thermal radiation detector means for controlling the power input to said means providing a reference source of thermal energy to equalize thermal radiation from said two thermal chamber means; and means for indicating the power supplied to said reference source of known thermal energy.
Claim 2
Dependent Claim
194 words
Apparatus for measuring the absolute power of unknown energy sources over a broad range of wavelengths comprising: first and second adjacently disposed thermal chamber means respectively having external surface portions for emitting thermal radiation along converging paths of travel, said first chamber means being responsive to energy received from a power source to be measured; means providing a reference source of thermal energy within said second thermal chamber means; isothermal housing means for maintaining said two thermal chamber means in a constant temperature environment; thermal radiation detector means disposed within said isothermal housing means for receiving thermal radiation along said converging paths of travel from said two thermal chamber means; means positioned between said thermal radiation detector means and said two thermal chamber means for alternately exposing said detector means to thermal radiation from said two thermal chamber means; means synchronized with said alternate exposing means and responsive to said thermal radiation detector means for controlling the power input to said means providing a reference source of thermal energy to equalize thermal radiation from said two thermal chamber means; and means for indicating the power supplied to said reference source of known thermal energy.
Claim 3
Dependent Claim
99 words
The apparatus of claim 1: said means providing a reference source of thermal energy including an electrical resistance heating element disposed within said second thermal chamber means; said means for controlling the power input to said means providing A reference source of thermal energy including amplifier means having an electrical output for energizing said electrical resistance heating element proportionately to the difference in thermal energy radiated by said two thermal chamber means; and said means for indicating the power supplied to said reference source of thermal energy including a power meter response to the output of said amplifier means.
Claim 4
Independent Claim
237 words
A device for accurately measuring radiated power from an unknown energy source comprising; first integrating chamber means including an inlet portion for receiving incident radiation from said unknown energy source to produce thermal radiation directed along a first path of travel; second integrating chamber means disposed adjacent to said second integrating chamber means and including electrical heating means for producing thermal radiation directed along a second path of travel; isothermal housing means for maintaining said first and second integrating chamber means in a constant temperature environment; mechanical means disposed adjacent to said first and second integrating chamber means for alternately interrupting said first and second paths of thermal radiation; single detector means for receiving said alternately interrupted paths of thermal radiation from said first and second integrating chamber means, said detector means producing an output signal having first and second components indicative of thermal radiation from said unknown energy source and said electrical heating means, respectively; phase-sensitive detector means synchronized with said mechanical alternate interrupting means and responsive to said single thermal radiation detector means for producing DC output power proportional in magnitude to the difference between said first and second signal components from said detector; means for connecting the output power from said phase-sensitive detector means to said electrical heating means; and means for measuring the output power from said phase-sensitive detector means to indicate the radiated power from said unknown energy source directly and absolutely.
Claim 5
Independent Claim
237 words
A device for accurately measuring radiated power from an unknown energy source comprising; first integrating chamber means including an inlet portion for receiving incident radiation from said unknown energy source to produce thermal radiation directed along a first path of travel; second integrating chamber means disposed adjacent to said second integrating chamber means and including electrical heating means for producing thermal radiation directed along a second path of travel; isothermal housing means for maintaining said first and second integrating chamber means in a constant temperature environment; mechanical means disposed adjacent to said first and second integrating chamber means for alternately interrupting said first and second paths of thermal radiation; single detector means for receiving said alternately interrupted paths of thermal radiation from said first and second integrating chamber means, said detector means producing an output signal having first and second components indicative of thermal radiation from said unknown energy source and said electrical heating means, respectively; phase-sensitive detector means synchronized with said mechanical alternate interrupting means and responsive to said single thermal radiation detector means for producing DC output power proportional in magnitude to the difference between said first and second signal components from said detector; means for connecting the output power from said phase-sensitive detector means to said electrical heating means; and means for measuring the output power from said phase-sensitive detector means to indicate the radiated power from said unknown energy source directly and absolutely.
Claim 6
Dependent Claim
66 words
The radiated power measuring device of claim 3: said first integrating chamber means also including electrical heating means for producing thermal radiation directed along said first path of travel; said second integrating chamber means also including an inlet portion for receiving incident radiation; and said isothermal housing means including two window portions respectively aligned with the inlet portions of said first and second integrating chamber means.
Claim 7
Dependent Claim
62 words
The device of claim 4, further including: movable shutter means for selectively blocking said two window portions to permit absorption of incident radiation by either one or both of said first and second integrating chamber means; and switch means for coupling output power from said phase-sensitive detector means to the electrical heating means of either said first or second integrating chamber means.
Claim 8
Dependent Claim
29 words
The power measuring device of claim 3, said mechanical alternate interrupting means including rotatable chopper wheel means having first and second portions for respectively obstructing and transmitting thermal radiation.
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) | 1974-02-15 | 1974-08-17 | 1975-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-15 | 1978-08-17 | 1979-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-15 | 1982-08-17 | 1983-02-16 | $7700.00 | Window Closed / Lapsed |