Flow Cytometer Laser Optics for Gaussian Beam Profiling

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Solution Overview

Problem

Flow cytometers face challenges in achieving precise and precise measurements of particle types and characteristics, particularly in achieving precise measurements of particle types and characteristics, particularly in achieving the Gaussian intensity profile of the core stream flow, with the Gaussian peak, and the Gaussian intensity profile of the flow cytometer, where the detected scattering signals are not, and the detected scattering signals are not.

Innovation Solution

A flow cytometer with a transverse-electric (TE) laser diode, a quarter wave plate (QWP), and a plurality of lenses, configured to output a laser beam with controlled divergence and polarization, and detectors to detect scattered light at specific angles, reducing profile intensity lobes and enhancing time-of-flight capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the laser beam width is increased to improve detection coverage, then the time-of-flight resolution for small particles deteriorates

Engineering Contradiction:
Improvebeam widthVSAvoidtime-of-flight resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating different beam characteristics in different spatial regions. The central portion of the beam maintains a narrow width for high TOF resolution, while the outer portions are shaped to eliminate intensity lobes. This is achieved through custom optical elements that apply different optical paths to different zones of the beam, allowing simultaneous optimization of both resolution and detection coverage without compromising either parameter.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If intensity lobes are present in the beam profile, then detection sensitivity improves, but measurement accuracy deteriorates due to false particle identification

Engineering Contradiction:
Improvedetection sensitivityVSAvoidmeasurement accuracy
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent converts the harmful intensity lobes into beneficial features by deliberately shaping the beam profile to eliminate them. The optical system is designed to create a smooth Gaussian-like intensity distribution without shoulders or peaks, transforming what would normally be considered a defect into an optimal characteristic. This eliminates false particle identifications while maintaining detection sensitivity through proper signal processing that focuses on the main Gaussian peak rather than spurious lobes.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution provides a flow cytometer with reduced profile intensity lobes, improved time-of-flight measurements, and enhanced detection of scattered light at specific angles, particularly in the Gaussian intensity profile, with the Gaussian intensity profile, with the Gaussian intensity profile, with the Gaussian intensity profile, and the detection of scattered light.

Implementation Method 1

The QWP is disposed along the optical axis between the TE laser diode and the flow cell and is configured to circularly polarize the laser beam as it passes therethrough

Methodology Applied
Scientific EffectCircular polarization: Polarisation

Implementation Method 2

The plurality of lenses is disposed between the TE laser diode and the flow cell. The lenses cooperate to focus the laser beam at the flow cell

Methodology Applied
Scientific EffectLight focusing: Lens

Implementation Method 3

particles flowing through the sample core stream are illuminated by the laser beam, absorbing and scattering the laser light in accordance with the refractive indices, sizes, shapes, and other properties of the particles

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4425235B1Flow cytometer and laser optics assembly thereof
Publication Date: 2025.12.24 IDEXX LABORATORIES INC
  • EP4425235B1 patent drawingFigure 1
  • EP4425235B1 patent drawingFigure 2
  • EP4425235B1 patent drawingFigure 3

AI summary

The present invention relates to a method of detecting reticulocytes and granulocytes, comprising: flowing a blood sample having at least one of reticulocytes or granulocytes, together with a sheath fluid, through a flow cell; emitting, from a transverse-electric laser diode, a laser beam along an optical axis, the laser beam having a fast axis FWHM divergence of from about 16 degrees to about 25 degrees; passing the laser beam through a quarter wave plate disposed along the optical axis between the TE laser diode and the flow cell to circularly polarize the laser beam as it passes therethrough; passing the laser beam through a plurality of lenses disposed between the TE laser diode and the flow cell to focus the laser beam at the flow cell; and detecting side-scattered light from the flow cell at angles of 50 degrees - 120 degrees relative to the optical axis.