MEMS Sensor Dual-Mode Capacitance Sensing Through Gel Coating

Solution Overview

Problem

Existing MEMS sensors face challenges in maintaining waterproofing while effectively measuring multiple physical parameters without requiring additional space-consuming structures or electrodes, especially in applications where moisture exposure is a concern.

Innovation Solution

Reusing existing MEMS sensor structures as electrodes for material sensing, such as poly membranes, and employing gel coatings to protect the sensor from moisture while allowing for dual operational modes to measure different physical parameters, including the presence of materials like water, by altering capacitance through electric stray fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If additional dedicated electrodes or structures are added to detect materials in contact with gel, then material sensing capability is improved, but device area and structural complexity increase

Engineering Contradiction:

Improvematerial sensing capabilityVSAvoidsensor area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent makes the existing MEMS sensor structures serve dual functions: their original sensing function and their function as electrodes for material detection. By configuring the measurement circuitry to operate in different modes, the same physical structures act as both the sensing element and the electrode, eliminating the need for separate dedicated electrodes and thereby preserving sensor area while enabling material sensing capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the sensing structure and the electrode into a single integrated component. The MEMS sensor structure that was previously used only for physical parameter measurement is now combined with electrode functionality to detect materials in contact with the gel, reducing overall device complexity and area by eliminating redundant components

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If additional dedicated electrodes or structures are added to detect materials in contact with gel, then material sensing capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvematerial sensing capabilityVSAvoidsensor structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the existing MEMS sensor structures serve dual functions: their original sensing function and their function as electrodes for material detection. By configuring the measurement circuitry to operate in different modes, the same physical structures act as both the sensing element and the electrode, eliminating the need for separate dedicated electrodes and thereby preserving sensor area while enabling material sensing capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the sensing structure and the electrode into a single integrated component. The MEMS sensor structure that was previously used only for physical parameter measurement is now combined with electrode functionality to detect materials in contact with the gel, reducing overall device complexity and area by eliminating redundant components

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If gel coating is applied to protect sensor from moisture, then waterproofing is improved, but material detection accuracy may be affected

Engineering Contradiction:

ImprovewaterproofingVSAvoidmaterial detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The gel coating acts as an intermediary layer that allows the sensor to function in both waterproof and material detection modes. The measurement circuitry is configured to detect capacitance changes that occur when materials contact the gel, enabling accurate material detection despite the presence of the gel barrier, while the gel simultaneously provides waterproof protection

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables robust, contactless material detection and accurate measurement of multiple parameters without additional space or electrodes, enhancing durability and sensitivity in harsh environments.

Implementation Method 1

measure the second physical parameter based on an electric stray field between the micro-mechanical sensing element acting as a first electrode of a capacitor and a further component of the MEMS sensor device acting as a second electrode of the capacitor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

measure the second physical parameter based on an electric stray field between the micro-mechanical sensing element acting as a first electrode of a capacitor

Methodology Applied

Scientific EffectElectric Field: Electric Field

Data Source

PatentUS20250333296A1MEMS sensor device and sensing method

Publication Date: 2025.10.30 INFINEON TECHNOLOGIES AG

AI summary

In an embodiment a MEMS sensor device includes at least one micro-mechanical sensing element and measurement circuitry coupled to the at least one micro-mechanical sensing element, wherein the measurement circuitry is configured, during a first operational mode of the MEMS sensor device, to control the at least one micro-mechanical sensing element to measure a first physical parameter, and, during a second operational mode of the MEMS sensor device, to control the at least one micro-mechanical sensing element to measure a different second physical parameter.