Patent US3645633A successfully refreshed from Google Patents.
US3645633A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chromacorder
Assignee: United States Department of the Army
•
Filing: 1971-01-11
•
Granted: 1972-02-29
•
Expires: 1991-01-11
Abstract
Abstract An instrument for the instantaneous measurement of the chromaticity of time variant spectral sources including a plurality of narrow band sensors or transducers that in combination encompass the visible spectrum. Each consists of an interference filter and a linear photovoltaic cell whose three output voltages have been ''''optimum multiplied'''' for the three tristimulus functions through a voltage divider network. The corresponding individual outputs of the sensors are added by a summing feedback amplifier to provide a voltage output proportional to the tristimulus values. These proportional outputs are then summed by a unity gain summing amplifier whose output in turn is applied to one input of a pair of ratio recorders. The other ratio recorder inputs each receive one of the proportional outputs. Each ratio recorder inputs each receive one of the proportional outputs. Each ratio recorder output, therefore, is one of the normalized chromaticity coordinates. The output coordinate values (x and y) are simultaneously fed into a chart recorder to derive a plot of the chromaticity coordinates vs. time. The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without the payment to us of any royalty thereon.
Inventors
- 👤 Paul J Kisatsky
- 👤 Louis R Szabo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 10:54
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/46; G01J3/465; G01J3/50; G01J3/51; G01J3/513
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
297 words
A device for measuring the instantaneous chromaticity values of a light sources which comprises: a plurality of filtered photodetectors each sensitive to a different narrow band of the visible spectrum and in combination sensitive to substantially the entire visible spectrum, for generating electrical signals proportional to visible light from said source impinging on them, circuit means connected to the output of each of said photodetectors to divide the signals among three current paths each of said paths receiving signals from each photodetector, and including further circuit means in each path to modify the voltage magnitude of the signal inputs to said circuit means to be proportional to a tristimulus value function of said source for said plurality of narrow bonds, three summing feedback amplifiers having feedback resistors and each having connected to its input one of said outputs of said three current paths, summing means having its input connected to receive the output of each of said summing feedback amplifiers for normalizing the tristimulus value signals, a pair of ratio forming means for forming chromaticity coordinates of said impinging light each having two inputs and providing an output wherein the output voltage is proportional to the ratio of the input voltages, one input of each of said ratio means connected to receive the output of said summing means, the other input of one of said ratio means connected to rEceive the output of one of said summing amplifiers, the other input of the other of said ratio means connected to receive the output of another of said summing amplifiers, an orthogonal time display means having a pair of inputs each connected to receive the output of one of said ratio means, and for indicating the instantaneous plot of the chromaticity coordinates vs. time of said light source.
Claim 2
Independent Claim
297 words
A device for measuring the instantaneous chromaticity values of a light sources which comprises: a plurality of filtered photodetectors each sensitive to a different narrow band of the visible spectrum and in combination sensitive to substantially the entire visible spectrum, for generating electrical signals proportional to visible light from said source impinging on them, circuit means connected to the output of each of said photodetectors to divide the signals among three current paths each of said paths receiving signals from each photodetector, and including further circuit means in each path to modify the voltage magnitude of the signal inputs to said circuit means to be proportional to a tristimulus value function of said source for said plurality of narrow bonds, three summing feedback amplifiers having feedback resistors and each having connected to its input one of said outputs of said three current paths, summing means having its input connected to receive the output of each of said summing feedback amplifiers for normalizing the tristimulus value signals, a pair of ratio forming means for forming chromaticity coordinates of said impinging light each having two inputs and providing an output wherein the output voltage is proportional to the ratio of the input voltages, one input of each of said ratio means connected to receive the output of said summing means, the other input of one of said ratio means connected to rEceive the output of one of said summing amplifiers, the other input of the other of said ratio means connected to receive the output of another of said summing amplifiers, an orthogonal time display means having a pair of inputs each connected to receive the output of one of said ratio means, and for indicating the instantaneous plot of the chromaticity coordinates vs. time of said light source.
Claim 3
Dependent Claim
33 words
The device according to claim 1 wherein each of said transducer means includes a photovoltaic cell and a narrow band interference optical filter disposed proximate and intermediate of said cell and said source.
Claim 4
Dependent Claim
32 words
The device according to claim 2 wherein said further circuit includes three resistive elements all connected in parallel across said cell and each having a variable output tap across a portion thereof.
Claim 5
Dependent Claim
22 words
The device according to claim 3 wherein said resistive elements are potentiometers and the tap thereof may be selectively adjusted for compensation.
Claim 6
Dependent Claim
26 words
The device according to claim 4 further including a high-resistive element disposed intermediate each of the outputs of said transducer means and said summing feedback amplifiers.
Claim 7
Dependent Claim
15 words
The device according to claim 5 wherein said summing means is a unity gain amplifier.
Claim 8
Dependent Claim
22 words
The device according to claim 6 wherein said ratio means are ratio recorders and said time display means is an x-y recorder.
Claim 9
Dependent Claim
22 words
The device according to claim 7 further including a chart recorder connected to receive the output of one of said summing amplifiers.
Claim 10
Independent Claim
180 words
A method for determining the instantaneous chromaticity values of a light source which comprises the steps of: a. detecting simultaneously in a plurality of narrow optical spectral bands spaced across the visible spectrum the light emitted bit said source, b. generating a plurality of electric signal proportional to the light energy in said narrow detected bands, c. converting each of said plurality of proportional signals into currents in three current paths corresponding to three tristimulus values, d. modifying electrically each of said proportional signals in accordance with standard tristimulus value functions for each detected band and the conversion efficiency of said conversion, e. summing each of the three modified current signals to obtain instantaneous tristimulus values of the detected light, f. resumming said three modified current signals to obtain the sum of said tristimulus values, g. comparing the ratio of said resummed current signals separately to at least each of two of said summed modified signals to determine at least two chromaticity coordinates of said detected light, simultaneously recording and displaying the ratio compared outputs on orthogonal axes vs. time.
Claim 11
Independent Claim
180 words
A method for determining the instantaneous chromaticity values of a light source which comprises the steps of: a. detecting simultaneously in a plurality of narrow optical spectral bands spaced across the visible spectrum the light emitted bit said source, b. generating a plurality of electric signal proportional to the light energy in said narrow detected bands, c. converting each of said plurality of proportional signals into currents in three current paths corresponding to three tristimulus values, d. modifying electrically each of said proportional signals in accordance with standard tristimulus value functions for each detected band and the conversion efficiency of said conversion, e. summing each of the three modified current signals to obtain instantaneous tristimulus values of the detected light, f. resumming said three modified current signals to obtain the sum of said tristimulus values, g. comparing the ratio of said resummed current signals separately to at least each of two of said summed modified signals to determine at least two chromaticity coordinates of said detected light, simultaneously recording and displaying the ratio compared outputs on orthogonal axes vs. time.
Claim 12
Dependent Claim
26 words
The method of claim 9 further including the step of: chart recording one of said modified summed signals to provide an indication of the source intensity.
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) | 1975-02-28 | 1975-08-30 | 1976-02-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-28 | 1979-08-30 | 1980-02-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-28 | 1983-08-30 | 1984-02-29 | $7700.00 | Window Closed / Lapsed |