Flow Cytometer Light Beam Shaping Module Using Cylindrical Lenses
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Solution Overview
Problem
Conventional flow cytometers face issues with narrow optical energy distribution in the cell-interrogation zone, leading to instability in signal detection and incorrect cell classification due to chaotic cell flow and significant aberration caused by ordinary spherical lenses, which result in false pulse signals and rejection of smaller cell signals.
Innovation Solution
A flow cytometer employing a light beam shaping module with a combination of cylindrical lenses and aspheric collimating lenses to create a uniformly distributed elliptical spot with a longer major axis, eliminating sidelobes and ensuring constant energy distribution, thereby stabilizing signal detection and improving accuracy without the need for complex signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an ordinary spherical lens is used to converge the light beam, then the light beam can be focused onto the cell-interrogation zone, but the energy distribution becomes narrow and chaotic cell flow causes signal instability
Solution Approach 1:
The patent applies cylindrical lenses instead of spherical lenses to create an anisotropic energy distribution that is locally optimized for the detection direction. The cylindrical lenses focus light primarily in the vertical direction (perpendicular to cell flow), creating a flat elliptical spot with extended major axis that provides consistent illumination intensity across the interrogation zone regardless of cell flow deviations.
Solution Approach 2:
The patent transitions from isotropic spherical lens focusing to anisotropic cylindrical lens focusing, adding directional dimensionality to the energy distribution. By using two cylindrical lenses with orthogonal orientations, the system creates a two-dimensional elliptical spot pattern that extends the energy distribution in the direction perpendicular to cell flow, thereby decoupling illumination stability from cell flow chaos.
2Ease of operation
If a normal spherical lens is used for collimation, then the light source can be positioned at the focus, but significant aberration occurs due to large divergence angle
Solution Approach 1:
The patent employs asymmetric cylindrical lens geometry instead of symmetric spherical lenses. The cylindrical lenses have different focal properties in orthogonal directions, with one direction (vertical) providing strong convergence and the other direction (horizontal) providing minimal convergence. This asymmetric design specifically addresses the large divergence angle problem by focusing energy only in the direction needed for detection, eliminating aberrations in the orthogonal direction.
Solution Approach 2:
The patent segments the collimation function into two separate cylindrical lenses with orthogonal orientations rather than using a single spherical lens. This segmentation allows independent optimization of collimation in different directions, with each cylindrical lens handling one dimensional aspect of the light beam, thereby reducing overall aberration while maintaining ease of setup.
3Illumination intensity
If the light beam is focused with a spherical lens, then a spot is formed, but sidelobes appear causing false pulse signals
Solution Approach 1:
The cylindrical lenses create a localized energy distribution concentrated in the vertical direction with minimal spread in the horizontal direction. This localized focusing eliminates the sidelobes that appear with spherical lenses, as the energy is confined to a flat elliptical spot pattern that matches the interrogation zone geometry, thereby preventing false pulse signals from sidelobe regions.
4Measurement precision
If threshold value method is used to eliminate sidelobes, then false accompanying signals can be rejected, but real scattered signals from smaller cells are also rejected
Solution Approach 1:
The patent extracts and eliminates the root cause of false signals (sidelobes) through optical design rather than relying on signal processing thresholds. By using cylindrical lenses to create a flat elliptical spot without sidelobes, the system removes the source of false accompanying signals, allowing all genuine scattered signals including those from smaller cells to be detected without artificial threshold rejection.
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 enhances the stability and reliability of optical signals, reduces false pulse detection, and improves the accuracy of cell classification by uniformly distributing light intensity along the major axis, ensuring consistent energy excitation even with deviated cell flow, and simplifies signal processing.
Implementation Method 1
a light beam shaping module with a combination of cylindrical lenses and aspheric collimating lenses to create a uniformly distributed elliptical spot
Implementation Method 2
a light beam shaping module with a combination of cylindrical lenses and aspheric collimating lenses
Implementation Method 3
the flow chamber provides an optical cell-interrogation zone, in which a sample flow of cells is encircled in a sheath flow according to the sheath flow principle (i.e., fluid focusing principle)
Implementation Method 4
the illuminating light beam may irradiate onto the cells (e.g., blood cells) flowing through the detection zone so as to be scattered, or excite fluorescence emission
Implementation Method 5
the illuminating light beam may irradiate onto the cells flowing through the detection zone so as to be scattered
Implementation Method 6
The photoelectric detection unit is useful for collecting various optical information generated in the flow chamber and converting it into electric signals
Data Source
AI summary
The present invention relates to a flow cytometer, comprising a light source, a light beam shaping module for collimating and converging a light beam emitted from the light source so that the light beam irradiates samples to be detected, a sample generation unit, which comprises a gas-liquid transmission controlling module and a flow chamber that are interconnected, and a signal processing unit, for collecting, photoelectrically converting and analyzing the scattered beam emitted from the flow chamber. The light beam shaping module comprises a first cylindrical lens and a second cylindrical lens for respectively converging the light beams in two directions. In the present invention, the spot converged at the cell-interrogation zone of the flow chamber is flattened to avoid instability of the fluid which in turn leads to instability of the excited optical signal, and consequently the stability and reliability of the system are improved.