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US3715922A
Expired / Lapsed
US
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Color pyrometer
Assignee: Siemens AG
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Filing: 1970-09-21
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Granted: 1973-02-13
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Expires: 1990-09-21
Abstract
Abstract A color pyrometer with two photo devices responding to different wavelengths and having output resistors connected in opposition. One resistor is controlled by a feedback voltage obtained from a differential amplifier responding to the voltage differential across the resistors to maintain the differential at 0. The controlled resistance or the feedback voltage is a measure of the ratio of received radiation intensities at the two wavelengths.
Inventors
- 👤 K Menge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:08
CPC Classifications
G; G01; G01J; G01J5/00; G01J5/60
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
In a color pyrometer for measuring the color temperatureproportional ratio of the radiation intensities of an object at a shorter wavelength and at a longer wavelength, the improvement comprising A. a first photosensitive device responsive to the shorter wavelength, B. a fixed resistance forming the load impedance of said first photosensitive device, C. a second photosensitive device connected in opposition to said first photosensitive device and responsive to the longer wavelength, D. a variable resistance means comprising a three-terminal semiconductor device forming the load impedance of said Second photosensitive device, E. a differential amplifier connected to said load impedances for receiving the differential of the voltage drops across said load impedances and F. means for applying a negative feedback voltage from said amplifier to said variable resistance means for varying the load impedance of said second photosensitive device to obtain a zero value of said differential; the magnitude of resistance of said variable resistance means at zero differential being proportional to the color temperature.
Claim 2
Dependent Claim
164 words
In a color pyrometer for measuring the color temperatureproportional ratio of the radiation intensities of an object at a shorter wavelength and at a longer wavelength, the improvement comprising A. a first photosensitive device responsive to the shorter wavelength, B. a fixed resistance forming the load impedance of said first photosensitive device, C. a second photosensitive device connected in opposition to said first photosensitive device and responsive to the longer wavelength, D. a variable resistance means comprising a three-terminal semiconductor device forming the load impedance of said Second photosensitive device, E. a differential amplifier connected to said load impedances for receiving the differential of the voltage drops across said load impedances and F. means for applying a negative feedback voltage from said amplifier to said variable resistance means for varying the load impedance of said second photosensitive device to obtain a zero value of said differential; the magnitude of resistance of said variable resistance means at zero differential being proportional to the color temperature.
Claim 3
Dependent Claim
164 words
In a color pyrometer for measuring the color temperature-proportional ratio of the radiation intensities of an object at a shorter wavelength and at a longer wavelength, the improvement comprising A. a first photosensitive device responsive to the shorter wavelength, B. a fixed resistance forming the load impedance of said first photosensitive device, C. a second photosensitive device connected in opposition to said first photosensitive device and responsive to the longer wavelength, D. a variable resistance means comprising a three-terminal semi-conductor device forming the load impedance of said Second photosensitive device, E. a differential amplifier connected to said load impedances for receiving the differential of the voltage drops across said load impedances and F. means for applying a negative feedback voltage from said amplifier to said variable resistance means for varying the load impedance of said second photosensitive device to obtain a zero value of said differential; the magnitude of resistance of said variable resistance means at zero differential being proportional to the color temperature.
Claim 4
Dependent Claim
164 words
In a color pyrometer for measuring the color temperature-proportional ratio of the radiation intensities of an object at a shorter wavelength and at a longer wavelength, the improvement comprising A. a first photosensitive device responsive to the shorter wavelength, B. a fixed resistance forming the load impedance of said first photosensitive device, C. a second photosensitive device connected in opposition to said first photosensitive device and responsive to the longer wavelength, D. a variable resistance means comprising a three-terminal semi-conductor device forming the load impedance of said Second photosensitive device, E. a differential amplifier connected to said load impedances for receiving the differential of the voltage drops across said load impedances and F. means for applying a negative feedback voltage from said amplifier to said variable resistance means for varying the load impedance of said second photosensitive device to obtain a zero value of said differential; the magnitude of resistance of said variable resistance means at zero differential being proportional to the color temperature.
Claim 5
Dependent Claim
17 words
An improvement as defined in claim 1, wherein said variable resistance means is a field effect transistor.
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) | 1976-02-13 | 1976-08-14 | 1977-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-13 | 1980-08-14 | 1981-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-13 | 1984-08-14 | 1985-02-13 | $7700.00 | Window Closed / Lapsed |