Microfluidic Valve Initialization Using Pressure Differential

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Solution Overview

Problem

Microfluidic devices with valves formed using thin polymer films face challenges in precisely and accurately controlling the on and off states, as the polymer film tends to adhere to the valve seat, leading to unreliable operation after manufacturing or prolonged inactivity.

Innovation Solution

A method and apparatus that utilize positive and negative pressures to separate and push the polymer film away from the valve seat, ensuring reliable initialization of valve states by supplying air pressure to the microfluidic channel and creating a vacuum in the corresponding space, allowing for repeated separation and repositioning of the film to maintain valve functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a thin polymer film is used to form valves in microfluidic channels, then the device structure is simplified and manufacturing is easier, but the polymer film adheres to the valve seat causing unreliable valve operation

Engineering Contradiction:

Improvevalve formationVSAvoidvalve operation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies preliminary action by performing valve initialization before actual microfluidic operation. The initialization process separates the polymer film from the valve seat surface in advance, ensuring the valve starts in a known open state and preventing adhesion issues during subsequent operations. This preliminary separation action resolves the reliability problem while maintaining the manufacturing simplicity of using thin polymer films.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If the polymer film is kept in contact with the valve seat for precise control, then valve closure is achieved, but the film adheres to the seat preventing reliable opening

Engineering Contradiction:

Improvevalve controlVSAvoidvalve opening

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The initialization process performs a preliminary separation of the polymer film from the valve seat before actual valve operation. This ensures that when the valve needs to open, the film is already separated and can respond reliably to opening signals, while still allowing precise control during closed state operation.

Inventive Principle:

Principle #10Preliminary action

3Duration of action of stationary object

If the microfluidic device is used after prolonged inactivity, then storage is achieved, but the polymer film adheres to the valve seat causing malfunction

Engineering Contradiction:

Improvestorage timeVSAvoidvalve function

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies preliminary action in two contexts: (1) initializing the valve before storage to prevent adhesion during inactivity, and (2) re-initializing the valve after storage before operation. This ensures the polymer film remains separated from the valve seat throughout storage periods, preventing adhesion-related malfunctions while allowing long-term storage capability.

Inventive Principle:

Principle #10Preliminary action

4Duration of action of moving object

If repeated valve operations are performed, then functionality is maintained, but adhesion accumulates causing degradation

Engineering Contradiction:

Improveoperational lifeVSAvoidvalve performance

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent implements periodic action by performing initialization at regular intervals - before storage periods and after prolonged inactivity. This periodic re-initialization prevents adhesion accumulation during repeated operations, maintaining valve performance and extending operational life by resetting the film-seat interface at appropriate intervals.

Inventive Principle:

Principle #19Periodic action

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 approach enhances the reliability of valve operation in microfluidic devices by preventing adherence and ensuring consistent opening and closing of valves, thereby improving the overall performance and accuracy of sample analysis in microfluidic devices.

Implementation Method 1

separating the polymer film from the surface of the valve seat by supplying a positive pressure to the microfluidic channel of the first substrate

Methodology Applied

Scientific EffectPositive pressure: Pressure Increase

Implementation Method 2

supplying a negative pressure to the space of the second substrate

Methodology Applied

Scientific EffectNegative pressure: Pressure Increase

Implementation Method 3

pushing the polymer film toward the valve seat by supplying the positive pressure to the space of the second substrate

Methodology Applied

Scientific EffectPositive pressure: Pressure Increase

Data Source

PatentUS8636033B2Microfluidic device initialization method, microfluidic device initialization apparatus and microfluidic device package

Publication Date: 2014.01.28 SAMSUNG ELECTRONICS CO LTD

AI summary

In a method for initialization of a microfluidic device including a first substrate including a microfluidic channel disposed therein, a valve seat disposed in a microfluidic channel and protruding from the first substrate, and a second substrate disposed opposite to the first substrate and including a space formed therein and corresponding to the valve seat, and a polymer film disposed between the first and second substrates, the method includes separating the polymer film from a surface of the valve seat by applying a positive pressure into the microfluidic channel of the first substrate and applying a negative pressure into the space of the second substrate.