Systems and methods for detecting scattered light from a particle using illumination incident at an angle

• US 20060227324A1
• Filed: 09/19/2005
• Published: 10/12/2006
• Est. Priority Date: 09/17/2004
• Status: Active Grant

• Current Assignee: JMAR LLC
• Original Assignee: JMAR Research Inc. (JMAR Technologies, Inc.)
• Inventors: Adams, John A., Crousore, Kristina M., Spivey, Brett A., Bloom, Scott H., Aguirre, Alex, Tutrow, Michael
• Granted Patent: US 7,532,327 B2
• Time in Patent Office: Days
• US Class Current: 356/343
• CPC Class Codes: G01N 15/1433 using image recognition
• CPC Class Codes: G01N 15/1459 the analysis being performed on a sample stream
• CPC Class Codes: G01N 15/147 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/019 Biological contaminants; Fouling
• CPC Class Codes: G01N 2015/1497 Particle shape
• CPC Class Codes: G01N 33/18 Water

Abstract

A particle detection system uses illumination incident at an angle to detect particles in a liquid such as water. By using illumination incident at an angle, the scattered light can be measured through a range of angles that are greater than the measured range of angles produced when the illumination is incident at a normal angle, when using the same detector. For example, the light can be measured through an angle that is twice that produced with illumination incident at a normal angle.

Claims

1. A system for detecting and identifying a particle, the system comprising:

an optical axis;

a target zone, the optical axis intersecting the target zone;

a detector configured to detect light scattered by a particle in the target zone; and

a light source configured to generate a light beam and direct the light beam through the target zone at an angle, the angle formed relative to the optical axis.

2. The system of claim 1, further comprising an optical element configured to receive the scattered light and direct the received scattered light to the detector.

3. The system of claim 2, wherein the optical element is a holographic optical element.

4. The system of claim 2, wherein the optical element is a zone plate lens.

5. The system of claim 2, further comprising an optical lens configured to collimate the scattered light and direct the collimated scattered light to the optical element.

6. The system of claim 1, wherein the target zone is within a flow cell and wherein the particle in a fluid within the flow cell.

7. The system of claim 1, wherein the detector comprises a plurality of detectors.

8. The system of claim 7, wherein the plurality of detectors form a linear detector array.

9. The system of claim 7, wherein the plurality of detectors form a 2 dimensional array.

10. The system of claim 7, wherein the plurality of detectors form a Charge Coupled Device (CCD).

11. The system of claim 1, wherein the detector is a linear photo diode camera.

12. The system of claim 1, wherein the detector is a square array of photodiodes.

13. The system of claim 1, wherein the detector comprises an array of photodiodes arranged in segmented concentric circles.

14. The system of claim 1, further comprising a beam stop configured to deflect the light beam after it has passed through the target zone.

15. The system of claim 6, wherein the light beam is internally reflected by the interface of the flow cell with the atmosphere eliminating the need for a beam stop to deflect the light beam after it has traveled through the target zone.

16. The system of claim 2, further comprising a plurality of light sources each configured to a produce a blight beam, wherein at least some of the light beams are incident at an angel relative to the optical access.

17. The system of claim 16, wherein each of the plurality of light sources is switched on and off at a rate that is fast compared to the transit of the particle through the light beams.

18. A system for detecting and identifying a particle, the system comprising:

an optical axis;

a target zone, the optical axis intersecting the target zone;

a detector configured to detect light scattered by a particle in the target zone, the detector positioned so as to capture scattered light rays scattered to an angle 2θ

; and

a light source configured to generate a light beam and direct the light beam through the target zone along the optical axis.

19. The system of claim 18, wherein the detector comprises a 64-pixel detector array.

20. The system of claim 18, wherein the detector comprises a 128-pixel detector array.

21. The system of claim 18, wherein the detector further comprises an Analog-to-Digital Converter (ADC) configured to convert analog signals produced by the detector into digital signals.

22. The system of claim 18, further comprising a processing system configured to receive signals form the detector and convert the signals into an optical pattern.

23. The system of claim 22, wherein the processing system is further configured to compare the optical pattern to at least one stored optical pattern.