Spring-Loaded Capacitive Touch Sensor for Stable Humid Operation

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Solution Overview

Problem

Capacitive touch sensors face reliability issues in industrial environments due to corrosion, vibration, and temperature variations, leading to inaccurate data input in high humidity and hazardous conditions.

Innovation Solution

A capacitive touch sensor design featuring a coil spring mechanism that securely couples an electrode to a circuit board, with an inverse cone region to maintain electrode position and prevent movement, ensuring consistent capacitance readings despite environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical buttons are used for data input, then the interface can accept user input, but the buttons are prone to corrosion and performance issues in high humidity environments

Engineering Contradiction:

Improvedata input capabilityVSAvoidbutton performance in humid environments

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical buttons with a capacitive touch sensor that detects changes in capacitance when a conductor (such as a human body) approaches or contacts the sensor surface. This eliminates mechanical moving parts that are susceptible to corrosion, while maintaining the ability to accept user input through touch interaction.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If infrared buttons are used for data input, then the interface can accept user input, but the buttons need calibration routines to operate reliably in both high and low temperature

Engineering Contradiction:

Improvedata input capabilityVSAvoidcalibration routines

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces infrared buttons with a capacitive touch sensor that measures capacitance changes directly. This eliminates the need for infrared transmission and reception systems that require calibration across temperature ranges, while maintaining touch input functionality through electrical field detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If exposed conductive induction buttons are used, then the interface can accept user input, but false button presses are registered in industrial environments

Engineering Contradiction:

Improvedata input capabilityVSAvoidfalse press registration

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent implements a non-conductive barrier layer between the capacitive touch sensor and the environment. This layer allows the sensor to detect capacitance changes from intentional touch inputs while preventing false registrations from environmental conductors such as moisture or dust, by selectively blocking unwanted electrical interference while maintaining touch sensitivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a non-conductive barrier layer as an intermediary between the capacitive touch sensor and the external environment. This barrier layer mediates the interaction by allowing capacitive coupling for intentional touch inputs while blocking parasitic capacitance from environmental conductors, thereby preventing false button presses.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If deformable sealing members are used to seal against humidity, then the flow meter can protect internal components, but the sealing member moves due to vibration

Engineering Contradiction:

Improvehumidity protectionVSAvoidsealing member position

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent employs a flexible non-conductive barrier layer that conformally seals around the capacitive touch sensor assembly. This flexible film maintains hermetic sealing against humidity and other environmental contaminants while accommodating vibrations and thermal expansion without compromising the positional stability of internal components.

Inventive Principle:

Principle #30Flexible shells and thin films

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 design enhances the reliability of capacitive touch sensors by maintaining consistent electrode position and capacitance measurements, reducing errors and improving performance in harsh industrial environments.

Implementation Method 1

a spring (130) that presses the electrode (110) towards the plate (120)

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

capacitive touch sensor (100) includes an electrode (110)

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3127242B1Capacitive touch sensor

Publication Date: 2020.05.27 MICRO MOTION INC

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AI summary

A capacitive touch sensor (100) is provided. The capacitive touch sensor (100) includes an electrode (110) disposed between a plate (120) and a spring (130) wherein the spring (130) presses the electrode (110) towards the plate (120) in a direction that is substantially parallel to a longitudinal length (L) of the spring (130) and the electrode (110) has a flat sensing surface (112) parallel with the plate (120).