Monolithic Optical Flow Cells via Glass Drawing

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Solution Overview

Problem

Existing optical flow cells for cytometric analysis face challenges in producing reliable, high-yield devices with polygonal cross-sections, as conventional methods result in low yields, optical aberrations, and failure modes due to complex assembly and joining processes, which affect the accuracy and longevity of cytometric differentiation of formed bodies.

Innovation Solution

A method involving the tube-drawing art to create monolithic optical flow cells with polygonal cross-sections, where a cylindrical preform is heated and drawn to maintain the desired non-circular geometry, allowing for the production of flow cells with improved reliability and reduced optical aberrations by eliminating the need for complex joins and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional assembly and joining processes are used to create optical flow cells with polygonal cross-sections, then the desired geometric shape can be achieved, but the manufacturing yield is low and failure rates are high due to complex assembly and joining processes

Engineering Contradiction:
Improvepolygonal cross-sectionVSAvoidmanufacturing yield
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent merges multiple separate components (walls, corners, joints) into a single monolithic piece of transparent material. This eliminates the need for assembly and joining processes, thereby achieving high manufacturing yield and reliability while maintaining the desired polygonal cross-section geometry.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the monolithic structure into functional zones (flow channel, optical path, joining regions) during the drawing process, allowing complex geometries to be formed in a single continuous operation without actual assembly steps.

Inventive Principle:
Principle #1Segmentation

2Shape

If conventional assembly methods are used to join multiple components, then polygonal geometry can be formed, but optical aberrations occur at the joins

Engineering Contradiction:
Improvepolygonal cross-sectionVSAvoidoptical quality
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

By combining all components into a single monolithic structure, the patent eliminates joints entirely, removing the source of optical aberrations that would occur at interfaces between different components with different refractive indices or surface imperfections.

Inventive Principle:
Principle #5Merging (Combining)

3Shape

If complex assembly processes are used to create flow cells with polygonal cross-sections, then the desired geometry is achieved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvepolygonal cross-sectionVSAvoidassembly complexity
Core Design Contradiction:
ShapeVSDevice complexity

Solution Approach 1:

The patent combines multiple manufacturing steps and components into a single drawing process, transforming a complex multi-step assembly operation into a simpler single-step forming process that produces the complete monolithic flow cell in one operation.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If monolithic structure is used to eliminate joins, then reliability and optical quality improve, but maintaining polygonal geometry during drawing becomes difficult

Engineering Contradiction:
Improvefailure rateVSAvoidgeometry maintenance
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-heating the transparent material to its softening point before drawing, making the material pliable enough to maintain complex polygonal geometry during the drawing process while still forming a monolithic structure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical state parameter of the transparent material from solid to softened state during drawing, enabling geometric shaping while maintaining material continuity. The controlled cooling after drawing then locks in the desired polygonal geometry.

Inventive Principle:
Principle #35Parameter changes

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 method significantly increases the yield of functional flow cells, reduces failure rates, and enhances the differentiation of formed bodies by maintaining the polygonal geometry during the drawing process, resulting in improved optical and Coulter parameter acquisition without the limitations of traditional composite flow cells.

Implementation Method 1

The preform is heated to a predetermined temperature at which its viscosity permits deformation

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

it is drawn axially, usually in a vertically downward direction, at a constant and predetermined rate

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP2356426B1Monolithic optical flow cells and method of manufacture
Publication Date: 2020.04.15 BECKMAN COULTER INC
  • EP2356426B1 patent drawingFigure 1
  • EP2356426B1 patent drawingFigure 2
  • EP2356426B1 patent drawingFigure 3

AI summary

An improved optical flow cell adapted for use in a flow cytometer for differentiating formed bodies (e.g., blood cells). Manufactured from a monolithic transparent material, the improved flow cell has an internal flow channel of polygonal transverse cross-section through which prepared samples can be metered and an external envelope suited to acquisition of optical parameters from formed bodies in such samples. Preferably, such flow cell is formed by a glass-drawing process in which a relatively large glass preform having a rectilinear internal channel of a desired polygonal cross- sectional shape is heated and drawn to achieve a desired cross-sectional area of reduced size. Also disclosed are preferred methods for differentiating formed bodies using the flow cell of the invention.