Capacitive Droplet Length Measurement Using Segmented Electrode

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Solution Overview

Problem

Existing droplet measurement devices face challenges in accurately measuring droplet length due to varying conductivity of substances and droplet velocity, leading to contamination of electrodes and high costs associated with single-use devices.

Innovation Solution

A capacitive electrode apparatus with a disposable panel and a reusable board, where the microfluid channel is separated from the sensing electrode by a thin film, allowing for non-contact measurement of droplet length using capacitance values regardless of droplet velocity or conductivity, and enabling electrode reuse.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the panel and board are integrally manufactured, then the device structure is simple, but the electrode is contaminated by fluid contact and cannot be reused

Engineering Contradiction:

Improvedevice structure simplicityVSAvoidelectrode contamination resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The device is divided into two separate components: a disposable panel containing the microfluid channel and a reusable board containing the sensing electrode. This segmentation prevents fluid contact with the electrode while maintaining measurement functionality, allowing the electrode to be reused across multiple experiments.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A thin film is introduced as an intermediary barrier between the microfluid channel and the sensing electrode. This thin film prevents direct contact between the fluid and electrode, eliminating contamination risks while still permitting the electrode to detect droplet properties through capacitance changes.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the electrode is discarded after single use to prevent contamination, then electrode contamination is prevented, but cost loss increases significantly

Engineering Contradiction:

Improveelectrode contamination preventionVSAvoidcost loss

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

By separating the disposable panel from the reusable electrode board, the system allows the expensive electrode to be retained and reused while discarding only the inexpensive panel. This segmentation eliminates the need to discard the electrode after single use, significantly reducing cost loss.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The thin film acts as a protective intermediary that enables electrode reuse by preventing fluid contamination. With this intermediary barrier, the electrode can be reused across multiple experiments without contamination risks, eliminating the need to discard it after single use and reducing associated cost losses.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If impedance measurement is used, then droplet length can be measured, but measurement precision deteriorates when substances have different conductivity or droplet velocity varies

Engineering Contradiction:

Improvedroplet length measurement accuracyVSAvoidmeasurement reliability across different substances and velocities

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces impedance-based measurement with capacitance-based measurement. Capacitance measurement measures the permittivity of the droplet rather than its conductivity, providing a more reliable measurement that is not affected by variations in droplet velocity or substance conductivity. This substitution of measurement principle improves both precision and adaptability.

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 apparatus allows for precise measurement of droplet length across varying substances with different permittivities and velocities, reducing costs by enabling electrode reuse and simplifying mass production for universal application.

Implementation Method 1

a sensing electrode unit patterned on an upper surface of the board and configured to measure a length of a droplet depending on a voltage value measured depending on a capacitance value of the fluid passing through the microfluid channel

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

a negative pressure forming means configured to apply a negative pressure between the disposable panel and the board so that the disposable panel and the board are attached to or detached from each other

Methodology Applied

Scientific EffectNegative pressure: Pressure Gradient

Data Source

PatentUS12044528B2Apparatus for measuring droplet length using capacitive electrode

Publication Date: 2024.07.23 INJE UNIVERSITY INDUSTRY ACADEMIC COOPERATION FOUNDATION

AI summary

Provided is an apparatus for measuring a droplet length using a capacitive electrode including: a disposable panel; a board separated from the disposable panel and configured to be reused separately from the disposable panel; a sensing electrode unit patterned on an upper surface of the board and configured to measure a length of a droplet depending on a voltage value measured depending on a capacitance value of the fluid passing through the microfluid channel; a thin film provided on a lower surface of the disposable panel; and a negative pressure forming means configured to apply a negative pressure between the disposable panel and the board so that the disposable panel and the board are attached to or detached from each other.