Reflectometry system with compensation for specimen holder topography and with lock-rejection of system noise
First Claim
1. A method of quantifying data to determine possible presence of a target analyte in a specimen in which a sample of said target analyte is placed upon a membrane having a spot region that, in the presence of said target analyte, changes at least one optical characteristic relative to surrounding regions of said membrane, the method comprising the following steps:
- (a) alternately and periodically illuminating said surrounding regions of said membrane and said spot region with light from a light source, said light traversing an air path undeflected by any planar optical element disposed between said light source and said membrane;
(b) detecting light reflected from said spot region and from said surround regions of said membrane with light detectors disposed so as to reduce skew error due to irregularities in topography of said membrane, reflected said light traversing an air path undeflected by any planar optical element disposed between said light detectors and said membrane;
(c) signal processing output from said light detectors to discern from optical characteristic information of said spot region relative to optical characteristic information of said surrounding regions of said membrane presence of said target analyte; and
(d) providing an output signal commensurate with an output from said signal processing.
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Abstract
A self-contained system uses light reflectivity to examine intensity of a dyed spot on a device membrane surrounded by background area to discern information about the specimen that produced the spot. In a preferred embodiment, a master clock alternatively drives one LED focussed upon the spot center, and then drives two LEDS focused on the background area. Light reflected from the spot and background is detected by preferably two photodetectors (“PDs”) spaced-apart a multiple of 90° azimuthal.
111 Citations
21 Claims
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1. A method of quantifying data to determine possible presence of a target analyte in a specimen in which a sample of said target analyte is placed upon a membrane having a spot region that, in the presence of said target analyte, changes at least one optical characteristic relative to surrounding regions of said membrane, the method comprising the following steps:
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(a) alternately and periodically illuminating said surrounding regions of said membrane and said spot region with light from a light source, said light traversing an air path undeflected by any planar optical element disposed between said light source and said membrane; (b) detecting light reflected from said spot region and from said surround regions of said membrane with light detectors disposed so as to reduce skew error due to irregularities in topography of said membrane, reflected said light traversing an air path undeflected by any planar optical element disposed between said light detectors and said membrane; (c) signal processing output from said light detectors to discern from optical characteristic information of said spot region relative to optical characteristic information of said surrounding regions of said membrane presence of said target analyte; and (d) providing an output signal commensurate with an output from said signal processing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A reflectometry system to measure intensity of a spot on a substrate relative to intensity of a surrounding area of said substrate, said spot being exposable to a target analyte, the system including:
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a master clock unit outputting at least a periodic master clock signal having a clock frequency and duty cycle; at least one light source, coupled to an output of said master clock unit, emitting light controllably directed at said spot and controllably directed at said surrounding area, emitted said light traveling substantially through air in a path undeflected by any planar optical element disposed between said light source and said substrate; first and second spaced-apart light detectors to detect fractions of emitted said light reflected by said surrounding area and by said spot, said first and second detectors disposed so as to reduce skew errors from irregularities in topography of said substrate, reflected said light traveling to said detectors substantially through air in a path undeflected by any planar optical element disposed between said light source and said substrate; circuitry, operatively synchronously with said master clock signal, to synchronously and complementarily sample and process output signals from said first and second light detectors, to provide data quantifying said target analyte. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification