Patent US3665380A successfully refreshed from Google Patents.
US3765776A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Calibrated densitometer accommodating various color tones
Assignee: Individual
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Filing: 1971-02-22
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Granted: 1973-10-16
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Expires: 1991-02-22
Abstract
Abstract A densitometer circuit uses a photo-multiplier tube to measure light levels. The tube is provided with an independent and preferably non-variant power supply connected between the cathode and first dynode. All other dynodes and anodes are powered by an RC decay circuit. Closure of a switch charges the RC circuit which consequently powers the photomultiplier tube. The tube compresses the signal in a manner yielding a logarithmic output signal. As an alternative embodiment, the densitometer circuit is adapted for use with several color tones wherein the various color tones are passed through selective filters with light passing therethrough falling on the light sensitive device, preferably the photo multiplier tube. The maximum amount of light will vary dependent on the color of the filter. The apparatus provides adjustments whereby the sensitivity of the apparatus is defined at two points and measurements at all other points therebetween are therefore accurate.
Inventors
- 👤 F Bravenec
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:50
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/25; G01N21/27; G01J; G01J3/00; G01J3/46; G01J3/50; G01J3/51
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
331 words
Optical density measuring apparatus for measuring and indicating the optical density of a sample, comprising: a. a photo multiplier tube having a cathode, a plurality of dynodes, and an anode; b. regulated light source means for directing a regulated level of light toward a sample; c. means for directing light from the sample, the quantity thereof being determined by the optical density of the sample, and directing light therefrom toward the cathode of said photomultiplier tube; d. a power supply; e. an RC circuit connected with said power supply and connected across the dynodes of said photo multiplier tube to provide operating voltages thereto; f. said RC circuit including intermediate taps for the dynodes of said photo multiplier tube, the voltage level provided by said taps being such that cathode of said photo multiplier tube is provided with the lowest voltage and the anode is provided with the highest voltage; g. voltage level detector means responsive to the voltage level at the anode of said photo multiplier tube and being further adjustable to determine a voltage level of predetermined magnitude at the anode thereof in response to a calibration of said optical density measuring apparatus to a standard or reference optical density and forming a signal on detection of a voltage level at the anode equal to the predetermined magnitude; h. second voltage detector means connected with said photo multiplier tube and responsive to a voltage level provided therefrom for detecting a subsequently occurring voltage level of said multiplier tube which is at least partially determined by the optical density of the sample and forming a signal on detection of a voltage level resulting from the optical density of the sample; i. pulse source means; j. digital register means; and, k. circuit means operated by said first and second voltage detection means for controllably connecting said pulse source to said register means for accummulating a count in said register means indicative of the optical density of the sample in digital representation.
Claim 2
Dependent Claim
331 words
Optical density measuring apparatus for measuring and indicating the optical density of a sample, comprising: a. a photo multiplier tube having a cathode, a plurality of dynodes, and an anode; b. regulated light source means for directing a regulated level of light toward a sample; c. means for directing light from the sample, the quantity thereof being determined by the optical density of the sample, and directing light therefrom toward the cathode of said photomultiplier tube; d. a power supply; e. an RC circuit connected with said power supply and connected across the dynodes of said photo multiplier tube to provide operating voltages thereto; f. said RC circuit including intermediate taps for the dynodes of said photo multiplier tube, the voltage level provided by said taps being such that cathode of said photo multiplier tube is provided with the lowest voltage and the anode is provided with the highest voltage; g. voltage level detector means responsive to the voltage level at the anode of said photo multiplier tube and being further adjustable to determine a voltage level of predetermined magnitude at the anode thereof in response to a calibration of said optical density measuring apparatus to a standard or reference optical density and forming a signal on detection of a voltage level at the anode equal to the predetermined magnitude; h. second voltage detector means connected with said photo multiplier tube and responsive to a voltage level provided therefrom for detecting a subsequently occurring voltage level of said multiplier tube which is at least partially determined by the optical density of the sample and forming a signal on detection of a voltage level resulting from the optical density of the sample; i. pulse source means; j. digital register means; and, k. circuit means operated by said first and second voltage detection means for controllably connecting said pulse source to said register means for accummulating a count in said register means indicative of the optical density of the sample in digital representation.
Claim 3
Dependent Claim
45 words
The invention of claim 1 wherein said RC circuit is connected across at least two dynodes of said photo multiplier tube and further including a voltage supply adapted to be connected to the anode of said photo multiplier tube to cause the current flow therethrough.
Claim 4
Dependent Claim
28 words
The invention of claim 2 further including an adjustable series resistor interposed between said additional voltage supply and said anode for controllably adjusting the current at said anode.
Claim 5
Dependent Claim
25 words
The invention of claim 2 further including multiple adjustable resistors controllably connected to said anode, each of which is adjustable to a separate voltage level.
Claim 6
Dependent Claim
52 words
The invention of claim 2 wherein four variable resistors are collectively connected to said additional voltage supply, and a switch means is selectively connected from said anode to one of said variable resistors to provide a DC level determining the point of operation of the anode current of said photo multiplier tube.
Claim 7
Dependent Claim
50 words
The invention of claim 5 further including color filters which are adapted to be selectively inserted at some point in the light path traversed by light from said light source to said photo multiplier tube in a manner to make said photo multiplier tube selectively responsive to colors passed thereby.
Claim 8
Dependent Claim
62 words
The invention of claim 2 further including a resistive circuit connected across at least a pair of dynodes of said photo multiplier tube for altering the rate of decay of voltage provided to said RC circuit connected with said photo multiplier tube, said resistive circuit being adjustable to provide an adjustable rate of decay to the voltage level at said RC circuit.
Claim 9
Dependent Claim
58 words
The invention of claim 7 wherein selected filters are adapted to be interposed in the light path of the light transferred from the sample to said photo multiplier tube for color selectivity and including an adjustable resistor for each of said light filters in said resistive network, and switch means selecting a resistor to match a light filter.
Claim 10
Dependent Claim
159 words
For use in a densitometer circuit including a light responsive means which forms an output signal indicative of the level of light falling on the light responsive means for a specimen wherein the light level is measured at least partially through the use of said light responsive means and said light responsive means causes the formation of a first current flowing in a portion of the densitometer with a value corresponding to a first predetermined light level and causes the formation of a second current flowing in a portion of said densitometer with a value corresponding to a second predetermined light level and said first and second currents are obtained from a common signal waveform, the improvement which comprises a first circuit means for controllably adjusting the first current and a second circuit means for controllably adjusting the second current flow, said first and second means operating independently of one another over at least a specified range of adjustment.
Claim 11
Dependent Claim
159 words
For use in a densitometer circuit including a light responsive means which forms an output signal indicative of the level of light falling on the light responsive means for a specimen wherein the light level is measured at least partially through the use of said light responsive means and said light responsive means causes the formation of a first current flowing in a portion of the densitometer with a value corresponding to a first predetermined light level and causes the formation of a second current flowing in a portion of said densitometer with a value corresponding to a second predetermined light level and said first and second currents are obtained from a common signal waveform, the improvement which comprises a first circuit means for controllably adjusting the first current and a second circuit means for controllably adjusting the second current flow, said first and second means operating independently of one another over at least a specified range of adjustment.
Claim 12
Dependent Claim
69 words
The invention of claim 9 including first and second filters which are adapted to be interposed at some point in the path of the light falling on the light responsive means to vary the spectrum of light falling on said light responsive means, and said first means comprises selectively operable means for adjusting the first current dependent upon which filter is selected to be interposed in the light path.
Claim 13
Dependent Claim
73 words
The invention of claim 9 wherein said light responsive means incorporates a photo multiplier tube having an anode, a cathode, and several dynodes, and further including: a voltage supply; an anode load impedance connected between the anode of said photo multiplier tube and said voltage supply to create a current flow through said anode load impedance; and, said first means being connected to controllably adjust the current flow in said anode load impedance.
Claim 14
Dependent Claim
38 words
The invention of claim 11 wherein said first means includes at least a pair of adjustable resistors which are connected with a voltage source and said resistors are adapted to be controllably adjusted to form differing voltage levels.
Claim 15
Dependent Claim
15 words
The invention of claim 12 wherein said adjustable resistors are selected by a switch means.
Claim 16
Dependent Claim
183 words
Optical density measuring apparatus which measures the optical density of a sample, comprising: a photo multiplier tube having an anode and cathode wherein said cathode is responsive to light falling thereon for altering the current flow in said photo multiplier tuBe; a power supply means operatively connected to the dynodes of said photo multiplier tube; means for controllably altering the voltage level provided to said photo multiplier tube from said power supply means; means for directing light from a sample to the cathode of said photo multiplier tube for altering the current flow therein in response to the light from such a sample; means operatively connected to the anode circuit of said photo multiplier tube for monitoring current flow thereof, said monitoring means responding to a current flow related to a sample of known optical density, and further responding to the current flow from said photo multiplier tube determined by such a sample of unknown density; and, output means connected to said monitoring means and forming an indication of optical density of such a sample in response to operation of said monitoring means.
Claim 17
Dependent Claim
183 words
Optical density measuring apparatus which measures the optical density of a sample, comprising: a photo multiplier tube having an anode and cathode wherein said cathode is responsive to light falling thereon for altering the current flow in said photo multiplier tuBe; a power supply means operatively connected to the dynodes of said photo multiplier tube; means for controllably altering the voltage level provided to said photo multiplier tube from said power supply means; means for directing light from a sample to the cathode of said photo multiplier tube for altering the current flow therein in response to the light from such a sample; means operatively connected to the anode circuit of said photo multiplier tube for monitoring current flow thereof, said monitoring means responding to a current flow related to a sample of known optical density, and further responding to the current flow from said photo multiplier tube determined by such a sample of unknown density; and, output means connected to said monitoring means and forming an indication of optical density of such a sample in response to operation of said monitoring means.
Claim 18
Dependent Claim
119 words
The invention of claim 14 wherein said power supply means and said means for altering the voltage level thereof together include: a power supply forming a DC level; an RC circuit connected across said photomultiplier tube wherein said anode is operated at a higher voltage than the other elements thereof; said RC circuit further including taps for a dynode incorporated in said photo multiplier tube to provide a voltage thereto intermediate between the voltage provided to the cathode and anode thereof; switch means for controllably connecting said power supply to said RC circuit to controllably increase the voltage thereacross; and, said monitoring means being connected with said RC circuit to provide signals thereto for operation of said monitoring means.
Claim 19
Dependent Claim
37 words
The invention of claim 15 further including a plurality of series resistors in said RC circuit, said tap for the dynode of said photo multiplier tube being connected at a point of interconnection between said series resistors.
Claim 20
Dependent Claim
14 words
The invention of claim 16 wherein said RC circuit means includes an adjustable capacitor.
Claim 21
Dependent Claim
46 words
The invention of claim 14 wherein said monitoring means incorporates a level detector means connected with the anode of said photo multiplier tube and responsive to the voltage level thereof, and is further operative to indicate coincidence with a voltage level representative of the known sample.
Claim 22
Dependent Claim
92 words
The invention of claim 14 further including: a. a numerical digital output means; b. a pulse source connected to said digital output means for providing a procession of pulses thereto; and, c. said output means admitting a number of pulses from said source of pulses as a means of indicating a variable count representative of the optical density of the sample, said means being operated in a manner to relate the number of pulses from said pulse source stored in said numerical digital output means to the density of the unknown sample.
Claim 23
Dependent Claim
89 words
The invention of claim 14 wherein said photo multiplier tube incorporates a plurality of dynodes, one of which is designated the first dynode, and which receives electron emission from the cathode thereof, and further including: a. isolated power supply means for providing an operating voltage above a predetermined level, said power supply means being connected between the cathode and the first dynode of said photo multiplier tube; and, b. wherein said power supply means is operatively connected to the first dynode to the anode of said photo multiplier tube.
Claim 24
Dependent Claim
40 words
The invention of claim 14 further including a light source providing a controlled quantity of light for the sample, and further including means for directing light from the sample to said photo multiplier tube for impinging on the cathode thereof.
Claim 25
Dependent Claim
90 words
The invention of claim 14 further including: a. a regulated light source; b. means for directing a regulated quantity of light from said light source to the sample; c. means for directing light from the sample originally directed thereto by said regulated light source, the amOunt thereof being determined by the optical density of the sample, said means redirecting the light from the sample to said photo multiplier tube; and, d. said photo multiplier tube being varied in its operation by the light impinging on the cathode from the sample.
Claim 26
Dependent Claim
51 words
The invention of claim 22 including fiber optics serving as a transmission means for light from such sample to said photo multiplier tube, said fiber optics providing a constant transmission loss such that variations in light level impinging on said photo multiplier tube include those variations caused by the sample itself.
Claim 27
Dependent Claim
39 words
The invention of claim 23 wherein said fiber optics means extends from the vicinity of said photo multiplier tube to a point remote therefrom and the remote end thereof is movable at least over a limited range of movement.
References Cited (Backward Citations)
US3435239A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-15 | 1977-04-16 | 1977-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-15 | 1981-04-16 | 1981-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-15 | 1985-04-16 | 1985-10-16 | $7700.00 | Window Closed / Lapsed |