Analytical Instrument Having Internal Reference Channel
First Claim
1. An analytical instrument comprising:
- a measurement interface associated with a test sample;
an illumination system for illuminating the measurement interface with light having rays incident to the measurement interface over a range of illumination angles, the illumination system including at least one light source and a diaphragm between the at least one light source and the measurement interface; and
a detector array arranged to detect light coming from the measurement interface, the detector array including a plurality of photosensitive pixels each providing a signal indicative of light intensity received thereby;
wherein the diaphragm has a first aperture, a second aperture, and an opaque region between the first and second apertures, the opaque region casting a shadow on the detector array to provide a reference minimum in light intensity at a location on the detector array, the location of the reference minimum being subject to signal drift over time as a result of instrument use.
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Accused Products
Abstract
An analytical instrument for making measurements based on detection of an SPR resonance minimum or a refractometer transition shadowline on a detector array is improved by configuring a diaphragm of the instruments illumination system to include a first aperture, a second aperture, and an opaque region between the first and second apertures, wherein the opaque region of the diaphragm casts a shadow on the detector array to provide a reference minimum from which a relative location of the resonance minimum or transition shadowline is measurable. By establishing a reference minimum on the detector array as a reference location for relative measurement, the instrument compensates for signal drift and other instrument variations. The diaphragm may include additional apertures and opaque regions for generating additional reference minima over the extent of the detector array.
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Citations
18 Claims
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1. An analytical instrument comprising:
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a measurement interface associated with a test sample; an illumination system for illuminating the measurement interface with light having rays incident to the measurement interface over a range of illumination angles, the illumination system including at least one light source and a diaphragm between the at least one light source and the measurement interface; and a detector array arranged to detect light coming from the measurement interface, the detector array including a plurality of photosensitive pixels each providing a signal indicative of light intensity received thereby; wherein the diaphragm has a first aperture, a second aperture, and an opaque region between the first and second apertures, the opaque region casting a shadow on the detector array to provide a reference minimum in light intensity at a location on the detector array, the location of the reference minimum being subject to signal drift over time as a result of instrument use. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 13)
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11. A method of compensating for signal drift in an analytical instrument having an illumination system for illuminating a measurement interface associated with a test sample, the method comprising the steps of:
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configuring the illumination system to cast at least one shadow on a detector array arranged to detect light coming from the measurement interface, wherein the shadow is located between illuminated regions of the detector array, to provide at least one corresponding reference minimum on the detector array, a location of the reference minimum being subject to signal drift over time as a result of instrument use; measuring the location of the at least one reference minimum on the detector array and a location of a feature of the detected light related to an analytical measurement; and using the location of the at least one reference minimum to correct for signal drift error in the location of the feature related to the analytical measurement. - View Dependent Claims (12, 14)
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15. In an analytical instrument for making measurements based on detection of a resonance minimum on a detector array, the resonance minimum resulting from surface plasmon resonance at an illuminated measurement interface, the improvement comprising:
a diaphragm including a first aperture, a second aperture, and an opaque region between the first and second apertures, wherein the opaque region of the diaphragm casts a shadow on the detector array to provide a reference minimum. - View Dependent Claims (16)
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17. In an analytical instrument for making measurements based on detection of a transition shadowline on a detector array, the transition shadowline resulting from critical angle reflection at an illuminated measurement interface, the improvement comprising:
a diaphragm including a first aperture, a second aperture, and an opaque region between the first and second apertures, wherein the opaque region of the diaphragm casts a shadow on the detector array to provide a reference minimum. - View Dependent Claims (18)
Specification