Microchip Gas Bubble Trapping Structure for Liquid Feed Control

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Solution Overview

Problem

Existing microreactor testing microchips face challenges in accurate liquid feed control due to gas bubbles blocking flow paths, leading to incomplete mixing of specimens and reagents and reduced testing accuracy.

Innovation Solution

Incorporation of a gas bubble trapping structure at the liquid feed control section, which includes a buffer path with a larger cross-sectional area than the liquid feed control path, prevents gas bubbles from flowing downstream and ensures accurate liquid control by allowing only liquid to pass at a predetermined pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a liquid feed control section with a small cross-sectional area is used to control liquid flow, then liquid feed control precision is improved, but gas bubbles block the flow path causing reliability to deteriorate

Engineering Contradiction:

Improveliquid feed control precisionVSAvoidflow path reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The flow path is segmented into three distinct sections: upstream flow channel, liquid feed control path, and downstream flow channel. The liquid feed control path with smaller cross-sectional area is isolated as a separate control zone, allowing precise liquid flow control while preventing gas bubbles from blocking the entire flow path. Gas bubbles are confined to the upstream section and cannot propagate to the downstream section.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The liquid feed control path acts as an intermediary element between the upstream and downstream flow channels. This intermediate section with restricted cross-sectional area serves as a gatekeeper that allows precise control of liquid flow while blocking gas bubbles from passing through, thus protecting the downstream flow channel from gas interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If gas bubbles are present in the liquid flow, then mixing of specimen and reagent is improved, but gas bubbles block flow paths causing measurement precision to deteriorate

Engineering Contradiction:

Improvemixing effectivenessVSAvoidtesting accuracy

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

Gas bubbles are extracted and removed from the liquid flow at the liquid feed control section. The control section's restricted cross-sectional area prevents gas bubbles from passing through, effectively separating and removing them from the specimen-reagent mixture before it reaches the testing section, thereby protecting measurement precision.

Inventive Principle:

Principle #2Taking out (Extraction)

3Device complexity

If a simple liquid feed control structure is used, then device complexity is reduced, but control accuracy over liquid flow deteriorates

Engineering Contradiction:

Improvecontrol structure complexityVSAvoidliquid flow control accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The liquid feed control path is designed with locally differentiated quality - it has a smaller cross-sectional area specifically at the control section while maintaining connection to larger upstream and downstream channels. This localized structural variation provides precise flow control capability without requiring complex control mechanisms throughout the entire device.

Inventive Principle:

Principle #3Local quality

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

This solution enables precise control over liquid flow, ensuring that specimens and reagents are mixed at the appropriate time and ratio, enhancing the accuracy and reliability of testing processes by preventing gas bubble interference.

Implementation Method 1

Due to surface tension, a predetermined feed pressure is needed in order to expel liquid from the liquid feed control path end 151a which has a small cross-sectional area (small diameter) to the downstream flow channel which has a large cross-sectional area (large diameter).

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Implementation Method 2

the gas bubble trapping structure is provided at the liquid feed control section and traps a gas bubble in the liquid that flows in the flow channel so that the gas bubble does not flow to the downstream side

Methodology Applied

Scientific EffectBuoyancy: Archimedes' Principle (Buoyancy)

Data Source

PatentUS7811521B2Testing microchip and testing apparatus using the same

Publication Date: 2010.10.12 KONICA MINOLTA MEDICAL & GRAPHICS INC

AI summary

A testing microchip includes a specimen storage section; a reagent storage section; a reaction section; a testing section for a test of a reaction product obtained from the reaction; a liquid feed control section; and a gas bubble trapping structure. The sections are connected continuously by a series of flow channels. The liquid feed control section stops passing of liquid until a liquid feeding pressure reaches a predetermined pressure, and passes the liquid when the liquid feeding pressure becomes higher than the predetermined pressure; and the gas bubble trapping structure traps a gas bubble in the liquid that flows in the flow channel so that the gas bubble does not flow to the downstream side and only the liquid passes to the downstream side. A testing apparatus that performs testing in the testing section of the testing microchip, wherein the testing microchip is attachably and detachably mounted to the apparatus.