Method to calibrate disposable cartridge cuvette thickness in-situ

Patent metadata

Field	Value
Publication number	US-10139263-B2
Application number	US-201313794241-A
Country	US
Kind code	B2
Filing date	Mar 11, 2013
Priority date	Mar 11, 2013
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

An analytical system includes a laser disposed to direct light toward a microfluidic feature disposed in a feature layer of a multiple layer test cartridge, a sensor to receive reflections from capping layers disposed about the microfluidic feature in the feature layer, and a controller to determine a depth of the microfluidic feature as a function of the received reflections.

First claim

The invention claimed is:

1. An analytical instrument comprising:
a microfluidic feature including a top capping layer on a first side of the microfluidic feature and a bottom capping layer on a second, opposite side of the microfluidic feature, the microfluidic feature disposed in a feature layer of a multiple layer test cartridge;
a first laser disposed to direct light toward the top capping layer of the microfluidic feature;
a first sensor disposed on the first side of the microfluidic feature to receive reflections from the top and bottom capping layers;
a second sensor disposed on the second side of the microfluidic feature to receive light that passes through the top capping layer, the microfluidic feature, and the bottom capping layer and produce a pass-through value based on the received light; and
a controller to determine a depth of the microfluidic feature as a function of the received reflections and the pass-through value.

2. The analytical instrument of claim 1 wherein the controller is programmed to determine a calibration value based on the depth of the microfluidic feature, the calibration value to be used in a measurement of a sample in the microfluidic feature.

3. The analytical instrument of claim 2 wherein the calibration value is determined from a lookup table.

4. The analytical instrument of claim 1 , wherein the microfluidic feature includes a cuvette and wherein the measured depth is a depth of the cuvette of the test cartridge.

5. The analytical instrument of claim 1 wherein the laser is disposed to direct light at a non-orthogonal angle to a top surface of the top capping layer and the first sensor comprises a photo detector array positioned to receive light reflected from the top capping layer and the bottom capping layer, wherein the reflections from the top and bottom capping layer are spaced apart in a direction generally perpendicular to a depth of the microfluidic feature, and wherein the controller determines the depth of the microfluidic feature based on a calculated distance between the top and bottom capping layers, the distance calculation based on the index of refraction of the top and bottom capping layers, the microfluidic feature, and the distance the reflection from the top and bottom capping layers are spaced apart; and
the analytical instrument further comprises a light source disposed to direct light to the top capping layer at an angle orthogonal to the top surface of the top capping layer, through the top capping layer, the microfluidic feature, and the bottom capping layer to the second sensor.

6. The analytical instrument of claim 1 , further comprising a mirror disposed in front of the first laser to redirect light from the first laser to be orthogonal to the top surface of the top capping layer, and the first sensor is an interferometer disposed to detect interference in reflections from the microfluidic feature.

7. The analytical instrument of claim 2 and further comprising:
a vacuum source coupled to the test cartridge to move fluid through microfluidic feature;
a light source disposed to direct light generally orthogonal to a top surface of the top capping layer and onto a sample in the microfluidic feature; and
wherein the controller adjusts the measurement of the sample as a function of the calibration, wherein the measurement of the sample is based on data received from the second sensor.

8. An analytical instrument comprising:
a housing;
a multiple layer test cartridge including a top capping layer, a bottom capping layer, and a microfluidic cuvette, the top capping layer on a first side of the and the bottom capping layer on a second side of the microfluidic cuvette opposite the first side;
a slot in the housing to register the multiple layer test cartridge in a selected position within the housing;
a laser disposed to direct light toward the top capping layer;
a first sensor disposed on the first side of the microfluidic cuvette to receive reflections from the top and bottom capping layers provide an output signal representative of the received reflections;
a second sensor disposed on the second side of the microfluidic cuvette to receive light that passes through the top capping layer, microfluidic cuvette, and the bottom capping layer and provide a measurement of a sample disposed in the microfluidic cuvette; and
a calibrator coupled to the first and second sensors to receive the output signal, determine a depth of the microfluidic cuvette based on the output signal, and adjust the determined depth based on the measurement.

9. The analytical instrument of claim 8 wherein the laser is disposed to direct light at a non-orthogonal angle to a top surface of the top capping layer, and the first sensor comprises a photo detector array positioned to receive light reflected from the top capping layer and the bottom capping layer, wherein the reflections from the top and bottom capping layer are spaced apart in a direction generally perpendicular to a depth of the microfluidic feature, and wherein the controller determines the calibration based on the depth of the microfluidic cuvette, the depth of the microfluidic cuvette determined by the controller based on a calculated distance between the top and bottom capping layers, the distance calculation based on the index of refraction of the top and bottom capping layers, the feature layer, and the distance the reflection from the top and bottom capping layers are spaced apart; and
the analytical instrument further comprises a light source disposed to direct light to the top capping layer at an angle generally orthogonal to the top surface of the top capping layer, through the top capping layer, the microfluidic feature, and the bottom capping layer to the second sensor.

10. The analytical instrument of claim 1 further comprising:
a pump configured to push a fluid into the microfluidic feature; and
wherein the controller is configured to determine a depth of the microfluidic feature using reflections received prior to the pump pushing fluid into the microfluidic feature and the controller is configured to adjust the determined depth of microfluidic feature using the received light after the pump has pushed the fluid into the microfluidic feature.

11. The analytical instrument of claim 8 further comprising:
a pump configured to push a fluid into the microfluidic cuvette; and
wherein the calibrator is configured to determine the prior to the pump pushing fluid into the microfluidic cuvette and the controller is configured to adjust the determined depth of microfluidic cuvette using the received light after the pump has pushed the fluid into the microfluidic cuvette.

Assignees

• Honeywell Int Inc

Inventors

• Wang Tzu-Yu

Classifications

• G01N21/05

  Flow-through cuvettes (G01N21/09 takes precedence; handling fluid samples G01N1/10) · CPC title

• G01N21/11

  Filling or emptying of cuvettes · CPC title

• G01N21/45

  using interferometric methods; using Schlieren methods · CPC title

• G01F25/0084 Primary

  for measuring volume · CPC title