Patent US4804850A successfully refreshed from Google Patents.
US4804850A
Expired / Lapsed
US
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Measurement of fluorescence
Assignee: Luminis Pty Ltd
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Filing: 1987-03-13
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Granted: 1989-02-14
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Expires: 2007-03-13
Abstract
Abstract A fluorometer probe head and a method of operating a probe to overcome problems of reflectance. A preferred embodiment for determination of chlorophyll in plant leaves uses a red LED and a green LED consecutively directed to a particular target spot and a photodiode records fluoresced and reflected signals to provide an accurate result.
Inventors
- 👤 Richard J. Norrish
- 👤 Joseph T. Wiskich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:36
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4738; G01N21/62; G01N21/63; G01N21/64; G01N2021/635; G01N2021/6417; G01N2021/6421; G01N2021/6491; G01N21/84; G01N2021/8466; G01N21/474; G01N2201/00; G01N2201/06; G01N2201/062; G01N2201/0621
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
136 words
A method of determining the instantaneous or transient fluorescence of a test sample at a test point, comprising the steps of (a) determining the gross reflectance and fluorescence value of a sample at a test point when excited by light from a first light emitting diode at a first known wavelength which causes at least fluorescence in the sample, (b) determining the reflectance at the test point by irradiating the sample with light from a second light emitting diode at a second wavelength which is known but different from the first wavelength and which does not cause fluorescence in the sample and (c) subtracting the reflectance from the gross reflectance and fluorescence value to give the fluorescence at the test point, wherein a single detector is used to make the determinations of steps (a) and (b).
Claim 2
Independent Claim
136 words
A method of determining the instantaneous or transient fluorescence of a test sample at a test point, comprising the steps of (a) determining the gross reflectance and fluorescence value of a sample at a test point when excited by light from a first light emitting diode at a first known wavelength which causes at least fluorescence in the sample, (b) determining the reflectance at the test point by irradiating the sample with light from a second light emitting diode at a second wavelength which is known but different from the first wavelength and which does not cause fluorescence in the sample and (c) subtracting the reflectance from the gross reflectance and fluorescence value to give the fluorescence at the test point, wherein a single detector is used to make the determinations of steps (a) and (b).
Claim 3
Dependent Claim
18 words
A method as in claim 1 wherein the irradiation with the first and second wavelengths is done consecutively.
Claim 4
Dependent Claim
29 words
A method as in claim 1 wherein the first wavelength is in the range of 655 nm to 677 nm and is supplied by a red light emitting diode.
Claim 5
Dependent Claim
28 words
A method as in claim 1 wherein the second wavelength is in the range of 556 to 580 nm and is supplied by a green light emitting diode.
Claim 6
Dependent Claim
25 words
A method as in claim 1 wherein the detector has a fluorescence sensitivity of electromagnetic radiation having wavelengths of from 750 nm to 1050 nm.
Claim 7
Dependent Claim
23 words
A method as in claim 1 wherein the irradiation is at a power of up to 200 microeinsteins per square meter per second.
Claim 8
Dependent Claim
42 words
A method as in claim 1 wherein instantaneous fluorescence and decay of fluorescence is determined by carrying out detections at sample times of 200, 300, 400, 500, 600, 700, 800, 900, 1000, 2000, 3000, 4000, 5000 and 6000 milliseconds during the irradiation.
Claim 9
Dependent Claim
85 words
A detector head for a device for measuring instantaneous or transient fluorescence, comprising a pair of light emitting diodes, the first of which is a red LED having a bandwidth of 655 to 677 nm and the second of which is a green LED having a bandwidth of 556 to 580 nm, positioned to provide respective emitted signals to a test point on a surface to be tested, and one detector positioned to receive reflected and fluoresced signals from the diodes from the test point.
Claim 10
Dependent Claim
85 words
A detector head for a device for measuring instantaneous or transient fluorescence, comprising a pair of light emitting diodes, the first of which is a red LED having a bandwidth of 655 to 677 nm and the second of which is a green LED having a bandwidth of 556 to 580 nm, positioned to provide respective emitted signals to a test point on a surface to be tested, and one detector positioned to receive reflected and fluoresced signals from the diodes from the test point.
Claim 11
Dependent Claim
20 words
A detector head as in claim 8 wherein a wave pass filter is operatively positioned in front of the detector.
Claim 12
Dependent Claim
25 words
A detector head as in claim 8 wherein the detector has a fluorescence sensitivity of electromagnetic radiation having wavelengths of from 750 to 1050 nm.
Claim 13
Dependent Claim
22 words
A detector head as in claim 8 wherein the diodes operate at a power of 200 microeinsteins per square meter per second.
Claim 14
Dependent Claim
13 words
A detector head as in claim 8, wherein the detector is a photodiode.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |