Apparatus and method employing incoherent light emitting semiconductor devices as particle detection light sources in a flow cytometer

• US 6,813,017 B1
• Filed: 10/19/2000
• Issued: 11/02/2004
• Est. Priority Date: 10/20/1999
• Status: Expired due to Term

• Current Assignee: Becton, Dickinson & Co
• Original Assignee: Becton, Dickinson & Co
• Inventors: Hoffman, Robert A., Chase, Eric S.
• Primary Examiner(s): Evans, F. L.
• Assistant Examiner(s): GEISEL, KARA E
• Application Number:
  US09/691,155
• Time in Patent Office: 1,475 Days
• Field of Search: 356/303, 356/317-318, 356/337-339, 356/410, 356/417, 356/72, 356/73, 250/458--46
• US Class Current: 356/317
• CPC Class Codes: G01N 15/1434 Optical arrangements
• CPC Class Codes: G01N 15/147 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/1447 Spatial selection
• CPC Class Codes: G01N 2015/1493 Particle size

Abstract

An apparatus and method for examining particles in a flow stream of a flow cytometer, employing incoherent light sources, such as light emitting diodes (LEDs), and detectors. The light emitting diodes operate as the excitation light sources and emit light toward said flow stream, and the detectors detect light, in particular, fluorescent light, emanating from the particles in response to the excitation light striking the particles. A controller controls each of the light emitting diodes to emit their excitation light for a predetermined period during which the excitation light radiates onto particles of interest. The controller evaluates the detected light to ascertain characteristics of the particles, such as particle size, density and granularity. The apparatus and method can further employ one or more coherent and homogenous light emitting devices, such as a laser, as an additional excitation light source. The detectors can detect the LED-excited fluorescence or the laser-excited fluorescence from the particles, and the controller can evaluate both types of detected light to ascertain characteristics of the particles. Furthermore, the controller can control the LEDs to operate in a pulsed manner, which can be synchronized with the detection of the laser-excited fluorescence or light scatter. In addition, a substantially opaque panel having one or more slits can be positioned at the image plane upon which an image of the flow stream is projected, so that the slits will allow only a portion of the image to pass to the detector associated with the panel.

Claims

1. An apparatus for examining a particle in a flow stream of a flow cytometer, comprising:

a light emitting device comprising at least one incoherent light emitting semiconductor device, adapted to emit light toward said flow stream;

a detector, adapted to detect light emanating from said particle in response to said emitted light striking said particle; and

a light obstructing device, having a substantially opaque portion which is adapted to prevent a portion of said emanating light from being detected by said detector, and at least two substantially transparent portions which are adapted to permit another portion of said emanating light to pass to said detector for detection by said detector;

wherein one of said transparent portions of said light obstructing device is larger than the other of said transparent portions.

2. An apparatus for examining a particle in a flow stream of a flow cytometer, comprising:

a light emitting device comprising at least one light emitting diode, adapted to emit light toward said flow stream;

a detector, adapted to detect light emanating from said particle in response to said emitted light striking said particle;

a controller, adapted to control said light emitting diode to emit said emitted light in pulses; and

a light obstructing device, having a substantially opaque portion which is adapted to prevent a portion of said emanating light from being detected by said detector, and at least two substantially transparent portions which are adapted to permit another portion of said emanating light to pass to said detector for detection by said detector;

wherein one of said transparent portions of said light obstructing device is larger than the other of said transparent portions.