Optical device and method for multi-angle laser light scatter

• US 6,646,742 B1
• Filed: 02/19/2000
• Issued: 11/11/2003
• Est. Priority Date: 02/19/2000
• Status: Expired due to Term

• Current Assignee: Boule Medical AB (Boule Diagnostics AB)
• Original Assignee: Mwi, Inc. (Escalon Medical Corporation)
• Inventors: von Behrens, Wieland E., Boyd, James R., Pina, Jean-Charles, Gangstead, Mervin L., West, Jerry B.
• Primary Examiner(s): STAFIRA, MICHAEL PATRICK
• Application Number:
  US09/507,431
• Time in Patent Office: 1,361 Days
• Field of Search: 356/342, 356/343, 356/337-341, 356/349, 356/38, 356/73, 356/442, 356/318, 356/72, 356/317, 250/573-575, 250/461.2
• US Class Current: 356/342
• CPC Class Codes: G01N 15/0205 by optical means
• CPC Class Codes: G01N 15/1404 Handling flow, e.g. hydrodynamic focusing
• CPC Class Codes: G01N 15/149 specially adapted for sorting particles, e.g. by their size or optical properties
• CPC Class Codes: G01N 2015/1413 Hydrodynamic focussing
• CPC Class Codes: G01N 21/532 with measurement of scattering and transmission

Abstract

The present invention relates to an optical system for an apparatus for multi-part differential particle discrimination to facilitate analysis, classification, and sorting of various fluid components for presentation. The optical system is characterized by one or more of the following: a synchronized illumination beam and flow cell conduit, a flow cell arrangement to control back reflection, and light sensor arrangement to particularly gather a specific range of light scatter, such specific range of light scatter directly corresponding to at least one type of particle capable of being identified by the apparatus.

Claims

1. A particle analyzing apparatus for discriminating particulate element(s) in a fluid flow for purposes of analysis, classification, sorting, and presentation, the apparatus comprising:

an illumination source to emit an illumination beam along an optical axis of the apparatus, wherein the illumination beam includes an intensity peak and at least one null;

a flow cell, positioned along the optical axis, having a flow path extending through the flow cell, the flow path having a portion of a surface to receive the illumination beam emitted from the illumination source, wherein the intensity peak of the illumination beam is substantially centered on the portion of the surface and the null of the illumination beam is positioned at an edge of the portion of the surface;

a sample supply to introduce a fluid to the flow path of the flow cell; and

a light sensor, positioned along the optical axis, to receive at least light passed from the flow cell in response to an interaction with an illumination beam emitted by the illumination source and a fluid supplied to the flow passage of the flow cell,

wherein the flow cell is oriented to prevent formation of back light reflection parallel to the optical axis in response to an emission of an illumination beam from the illumination source.

2. An apparatus in accordance with claim 1, wherein the illumination source is a solid-state laser diode.

3. An apparatus in accordance with claim 1, wherein the flow cell is not orthogonal to an illumination beam emitted by the illumination source.

4. An apparatus in accordance with claim 1, further comprising a focusing optical system, positioned between the illumination source and the flow cell, to form and to position a beam waist of an emitted illumination beam within the flow passage.

5. An apparatus in accordance with claim 4, comprising a collection optical system, positioned between the flow cell and the light sensor, to collect light passed by the flow cell and further pass such light to the light sensor.

6. An apparatus in accordance with claim 1, wherein the flow cell is displaced by an angle relative to a direction orthogonal to the optical axis, and the angle is between 2.5°

-10°

.

7. An apparatus in accordance with claim 1, further comprising a reflective surface to intercept and redirect in direction a component of at least light passed from the flow cell in response to an interaction with an illumination beam emitted by the illumination source and a fluid supplied to the flow path of the flow cell, and a light sensor to receive the component.

8. An apparatus in accordance with claim 1, wherein the portion of an exterior surface of the flow cell positioned to receive an emitted illumination beam from the illumination source does not have an anti-reflective coating.

9. An optical system for a particle analyzing apparatus for discriminating particulate element(s) in a fluid flow for purposes of analysis, classification, sorting, and presentation, the apparatus having an illumination source for emitting an illumination beam and at least one light sensor to receive at least a light component of an emitted illumination beam, the system comprising:

a focusing optical system, positioned along an optical axis of the system, to receive an illumination beam emitted by the illumination source and provide a focused illumination beam, wherein the focused illumination beam includes an intensity peak and at least one null; and

a flow cell, positioned along an optical axis of the system and prior to the at least one light sensor, having a flow passage, through which a fluid flow containing particles can pass, the flow passage having a surface portion to receive light passed by the focusing optical system, wherein the intensity peak of the focused illumination beam is substantially centered on the surface portion and the null of the illumination beam is positioned at an edge of the surface portion,

wherein the surface portion to receive an illumination passed by the focusing optical system of the flow cell is not orthogonal to the optical axis of the system.

10. An optical system in accordance with claim 9, wherein an exterior surface portion of the flow cell does not have an anti-reflective coating.

11. An optical system in accordance with claim 9, further comprising a reflective surface to intercept and redirect in direction a component of at least light passed by the flow cell, and a light sensor to receive the component.

12. A particle analyzing apparatus for discriminating particulate element(s) in a fluid flow for purposes of analysis, classification, sorting, and presentation, the apparatus comprising:

an illumination source to emit an illumination beam;

a flow cell having a flow passage extending through the flow cell, the flow path having a first surface portion that is adapted to receive an illumination beam emitted by the illumination source, and a second surface portion that passes light formed from an illumination beam received by the first surface portion;

a sample supply to introduce a fluid containing particles to the flow passage of the flow cell;

a focusing optical system, positioned between the illumination source and the flow cell and having an aperture, to form and to position a beam waist of an emitted illumination beam relative to the flow passage; and

a first light sensor to receive light passed by the flow cell,

wherein an emitted illumination beam has an intensity profile characterized by a central, principal intensity peak that originates and terminates at substantially null intensities, and

wherein the flow cell is further arranged relative to the illumination source so that the principal intensity peak is substantially centered with respect to the flow passage, and such illumination beam intercepts, proximate to the null intensities, internal lateral boundaries of the flow cell, which define at least in part the flow passage.

13. An apparatus in accordance with claim 12, wherein the flow cell has a first axis, which is substantially co-axial with an optical axis of the apparatus, and a second axis, which is orthogonal to the first axis.

14. An apparatus in accordance with claim 13, wherein a light receiving surface of the first light sensor is substantially parallel to the axis of an illumination beam emitted from the illumination source, and the first light sensor is displaced a prescribed distance from the second axis.

15. An apparatus in accordance with claim 14, wherein the first light sensor receives a specific range of light passed from the flow cell in response to an interaction with an illumination beam emitted by the illumination source and a fluid supplied to the flow passage of the flow cell, such specific range extending between at least 30°

and no greater than 45°

relative to the first axis.

16. An apparatus in accordance with claim 12, further comprising light extinguishing means, which is adapted to intercept and to substantially prevent passage of at least a portion of light passed by the flow cell to the first light sensor.

17. An apparatus in accordance with claim 12, wherein the illumination source is a solid-state laser diode.

18. An apparatus in accordance with claim 12, wherein the first surface portion of the flow cell, which is adapted to receive an illumination beam emitted by the illumination source, is not orthogonal to an illumination beam emitted by the illumination source.

19. An apparatus in accordance with claim 12, where in the flow cell is displaced by an angle relative to a direction orthogonal to an illumination beam emitted by the illumination source, and the angle is between 2.5°

-10°

.

20. An apparatus in accordance with claim 12, further including a second light sensor, positioned substantially orthogonal to an axis of an illumination beam emitted by the illumination source, to receive light from the illumination source via the flow cell.

21. An apparatus in accordance with claim 12, wherein the intensity profile is defined by:

22. A particle analyzing apparatus for discriminating particulate element(s) in a fluid flow for purposes of analysis, classification, sorting, and presentation, the apparatus comprising:

an illumination source to emit an illumination beam along an optical axis of the apparatus, wherein the illumination beam includes an intensity peak and at least one null;

a flow cell, positioned along the optical axis, having a flow path extending through the flow cell, the flow path having a portion of a surface to receive an illumination beam emitted from the illumination source, wherein the intensity peak of the illumination beam is substantially centered on the portion of the surface and the null of the illumination beam is positioned at an edge of the portion of the surface;

a sample supply to introduce a fluid to the flow path of the flow cell; and

at least one light sensor, positioned along an optical path of the apparatus, to receive at least light passed from the flow cell in response to an interaction with an illumination beam emitted by the illumination source and a fluid supplied to the flow passage of the flow cell,

wherein the flow passage has a longitudinal axis, and

wherein the longitudinal axis of the flow passage is angularly displaced from an axis perpendicular to the optical axis so that the flow cell is oriented to prevent a back light reflection that is parallel to the optical axis in response to an emission of an illumination beam from the illumination source.

23. A method for optically differentiating at least one type of particulate element carried by a fluid filament, the method comprising the steps of:

emitting a laser beam from a laser source along an optical path and through a flow cell having an internal passageway that receives the fluid filament;

sensing at least a portion of light scatter produced by an interaction between a particulate element, carried by the fluid filament, and the laser beam; and

analyzing sensed light scatter to identify the particulate element,

wherein internal boundaries define the internal passageway of the flow cell, and

wherein the flow cell is arranged relative to the optical path so that at least one null in the intensity pattern of the laser beam is positioned proximate to the internal boundaries.