Microfluidic Rotor Bonding via Infrared Laser Welding

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Solution Overview

Problem

Conventional fluid analysis systems face challenges in efficiently analyzing biological samples due to difficulties in inspecting rotor welds and generating undesirable noise from asymmetric fluid flow during centrifugation, which complicates the process and reduces the desirability of rotor use in point-of-care settings.

Innovation Solution

A method involving two-shot injection molding to bond layers, where one layer is transparent to ultraviolet and infrared radiation, and another is substantially absorbent, establishing a fluid communication path, and using infrared radiation to bond additional layers, improving rotor design and reducing noise through balanced mass distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional bonding methods are used to assemble rotor layers, then manufacturing complexity is reduced, but manufacturing precision and bond quality are insufficient

Engineering Contradiction:
Improvebond qualityVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical bonding methods with infrared laser welding. The infrared radiation source melts the polymer layers through thermal energy, creating strong bonds without mechanical pressure or complex assembly fixtures, thereby improving bond quality while maintaining manufacturing simplicity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the differential infrared absorption properties of different polymer layers to achieve selective bonding. The first layer absorbs infrared radiation and melts to form bonds, while the second layer transmits infrared radiation and remains unaffected, enabling precise control of bonding parameters to achieve high manufacturing precision

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If asymmetric fluid flow is used in the rotor, then fluid analysis functionality is achieved, but undesirable noise is generated during centrifugation

Engineering Contradiction:
Improvefluid analysis functionalityVSAvoidnoise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent employs asymmetric fluid flow paths within the rotor design to enable functional fluid analysis. The asymmetric channels and chambers are strategically positioned to maintain centrifugal balance, allowing efficient fluid distribution and mixing while minimizing vibration and noise during rotation

Inventive Principle:
Principle #4Asymmetry

3Measurement precision

If rotor welds are inspected using conventional methods, then inspection process is simple, but inspection precision is insufficient

Engineering Contradiction:
Improveinspection precisionVSAvoidinspection time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces conventional visual or tactile inspection methods with optical imaging technology. The imaging system captures high-resolution images of rotor welds, enabling precise detection of bond quality, cracks, or defects without time-consuming manual examination, thereby improving inspection precision while maintaining efficiency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the efficiency of fluid analysis by simplifying rotor inspection, reducing noise during centrifugation, and improving rotor quality, making it more suitable for point-of-care applications.

Implementation Method 1

bonding a first layer (201) and a second layer (202) using two-shot injection molding

Methodology Applied
Scientific EffectTwo-shot injection molding:

Implementation Method 2

the second layer (202) being substantially absorbent to infrared radiation

Methodology Applied
Scientific EffectInfrared radiation absorption: Absorption (EM radiation)

Implementation Method 3

absorbing infrared radiation in a sufficient amount within a predetermined period of time to transition the second layer from a solid phase to a molten phase

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 4

The third layer may be bonded to the second layer and include using an infrared laser beam

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3840884B1Methods for manufacturing a microfluidic rotor device
Publication Date: 2023.09.13 ZOETIS SERVICES LLC
  • EP3840884B1 patent drawingFigure 1A
  • EP3840884B1 patent drawingFigure 1B
  • EP3840884B1 patent drawingFigure 2A

AI summary

Described herein are various embodiments directed to rotor devices, methods, and systems. Embodiments of rotors disclosed herein may be used to characterize one or more analytes of a fluid. A manufacturing method may include bonding a first layer and a second layer using two-shot injection molding. The first layer coupled to the second layer collectively defines a set of wells or cuvettes. The first layer is substantially transparent. The second layer defines a channel. The second layer is substantially absorbent to infrared radiation and may comprise some amount of carbon black or of a laser absorbing dye. A third layer is bonded to the second layer using infrared radiation, e.g. using a near-infrared radiation at a wavelength of about 940 nm. The third layer defines an opening configured to receive a fluid and is substantially transparent. The channel establishes a fluid communication path between the opening and the set of wells. By combining injection molding and laser welding techniques, the method may lead to a reduced risk of contamination by limiting the formation of dust within a well during manufacturing of a rotor device.