Optical detection system with polarizing beamsplitter

• US 20050118723A1
• Filed: 12/30/2004
• Published: 06/02/2005
• Est. Priority Date: 08/02/2000
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Padmanabhan, Aravind, Fritz, Bernard S.
• Granted Patent: US 7,471,394 B2
• Time in Patent Office: Days
• US Class Current: 436/164
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150213 Venting means
• CPC Class Codes: A61B 5/150221 Valves
• CPC Class Codes: A61B 5/150343 Collection vessels for collecting blood samples from the skin surface, e.g. test tubes, cuvettes sampling from within body cavities A61B5/150015, A61B5/150045
• CPC Class Codes: A61B 5/150351 Caps, stoppers or lids for sealing or closing a blood collection vessel or container, e.g. a test-tube or syringe barrel caps for bottles or containers in general B65D41/00
• CPC Class Codes: A61B 5/157 Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: G01F 1/7086 using optical detecting arrangements
• CPC Class Codes: G01N 15/1404 Handling flow, e.g. hydrodynamic focusing
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/016 White blood cells
• CPC Class Codes: G01N 2015/1486 Counting the particles

Abstract

An optical detection system for use in flow cytometry or the like, which includes a polarizing beamsplitter 820 such as a Wollaston prism. A light source provides an input light beam to a flow stream, wherein the input light beam has a polarization direction. The particles in the flow stream may produce an output light beam that includes a polarized component and a depolarized component. The polarizing beam splitter receives the output light beam, and provides a polarized light beam and a depolarized light beam to a pair of detectors. The pair of detectors provide a first output signal that corresponds to the polarized light beam and a second output signal that corresponds to the depolarized light beam. A controller or processor may use the first output signal and the second output signal to help identify/classify particles and/or particle characteristics in the flow stream.

Claims

1. An optical detection system for analyzing predetermined characteristics of a flow stream, the optical detection system comprising:

a light source for providing an input light beam to the flow stream, the input light beam having a polarization direction;

a polarizing beamsplitter for receiving an output light beam from the flow stream, and for providing a polarized light beam and a depolarized light beam, wherein the polarized light beam and the depolarized light beam form an angle therebetween of less than 90 degrees; and

light receiving means for receiving the polarized light beam and the depolarized light beam, and for providing a first output signal that corresponds to the polarized light beam and a second output signal that corresponds to the depolarized light beam.

2. The optical detection system of claim 1 wherein the output light beam includes scattered light, and the polarizing beamsplitter receives a portion of the output light beam that is scattered in a direction that is about 90 degrees offset relative to the input light beam.

3. The optical detection system of claim 2 wherein the polarizing beamsplitter includes a Wollaston prism.

4. The optical detection system of claim 1 wherein the angle formed between the polarized light beam and the depolarized light beam is less than 20 degrees.

5. The optical detection system of claim 1 wherein the angle formed between the polarized light beam and the depolarized light beam is less than 10 degrees.

6. The optical detection system of claim 1 wherein the polarizing beamsplitter is a polarizing beamsplitter cube.

7. The optical detection system of claim 1 wherein the polarizing beamsplitter is a polarizing beamsplitter film.

8. The optical detection system of claim 1 wherein the light receiving means includes a pair of photodetectors.

9. The optical detection system of claim 1 wherein the polarized light beam has the same polarization as the input light beam.

10. The optical detection system of claim 9 wherein the depolarized light beam has a polarization that is orthogonal to the polarization of the input light beam.

11. The optical detection system of claim 1, further comprising processing means, the processing means using the first output signal and the second output signal to help classify white blood cells.

12. The optical detection system of claim 11, wherein the white blood cells include eosinophils.

13. A method for analyzing predetermined characteristics of a flow stream, the method comprising:

providing an input light beam to the flow stream, the input light beam having a polarization direction;

providing an output light beam from the flow stream to a polarizing beam splitter, the polarizing beamsplitter providing a polarized light beam and a depolarized light beam, wherein the polarized light beam and the depolarized light beam form an angle therebetween of less than 90 degrees;

detecting the polarized light beam and the depolarized light beam, and providing a first output signal that corresponds to the polarized light beam and a second output signal that corresponds to the depolarized light beam.

14. The method of claim 13 wherein the output light beam that is provided to the polarizing beamsplitter is scattered about 90 degrees relative to the input light beam by the flow stream.

15. The method of claim 13 wherein the angle formed between the polarized light beam and the depolarized light beam is less than 20 degrees.

16. The method of claim 13 wherein the angle formed between the polarized light beam and the depolarized light beam is less than 10 degrees.

17. The method of claim 13 wherein the polarizing beamsplitter is a polarizing beamsplitter cube.

18. The method of claim 13 wherein the polarizing beamsplitter is a polarizing beamsplitter film.

19. The method of claim 13 wherein the polarizing beamsplitter includes a Wollaston prism.

20. The method of claim 13 wherein the polarized light beam and the depolarized light beam are detected using a pair of photodetectors.

21. The method of claim 13 wherein the polarized light beam has the same polarization as the input light beam.

22. The method of claim 13 wherein the depolarized light beam has a polarization that is orthogonal to the polarization of the input light beam.

23. An optical detection system for analyzing predetermined characteristics of a flow stream, the optical detection system comprising:

a light source for providing an input light beam to the flow stream, the input light beam having in incident angle relative to the flow stream and a polarization direction;

a polarizing beamsplitter for receiving a scattered output light beam from the flow stream, the scattered output light beam being scattered about 90 degrees relative to the incident angle of the input light beam, the polarizing beamsplitter providing a polarized light beam and a depolarized light beam, wherein the polarized light beam and the depolarized light beam form an angle therebetween of less than 90 degrees; and

light receiving means for receiving the polarized light beam and the depolarized light beam, and for providing a first output signal that corresponds to the polarized light beam and a second output signal that corresponds to the depolarized light beam.

24. The optical detection system of claim 23 wherein the polarized light beam has the same polarization as the input light beam.

25. The optical detection system of claim 24 wherein the depolarized light beam has a polarization that is orthogonal to the polarization of the input light beam.