Projective Capacitive Touch Interface for Fluid-Resistant Industrial Control

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Solution Overview

Problem

Industrial control interfaces for temperature controllers face issues with physical buttons that wear out, break, and provide leak paths for fluids, and are prone to unintended activation due to their mechanical nature and exposure to extreme conditions.

Innovation Solution

The design incorporates a capacitive slider sensor and input graphics molded into a transparent polymer body, allowing for durable, fluid-resistant, and aesthetically appealing interfaces that use capacitive sensing for input, eliminating the need for physical buttons and enhancing durability and functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If physical buttons are used for input, then the interface is easy to operate, but the buttons wear out and break over time, reducing reliability

Engineering Contradiction:
Improveinput operationVSAvoidbutton durability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent replaces mechanical physical buttons with a capacitive touch interface that detects changes in capacitance when a conductor (such as a finger) approaches or contacts the surface. This eliminates moving parts and mechanical wear, providing a reliable, maintenance-free input mechanism while maintaining ease of operation through intuitive touch interactions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a transparent polymer overlay with integrated capacitive sensors that acts as a flexible yet durable interface layer. This thin film structure provides a smooth, continuous surface for touch input without the need for discrete mechanical buttons, combining durability with operational simplicity.

Inventive Principle:
Principle #30Flexible shells and thin films

2Ease of operation

If physical buttons are used for input, then the interface provides tactile feedback, but the buttons create leak paths for fluids and are prone to unintended activation

Engineering Contradiction:
Improveinput controlVSAvoidfluid exposure and unintended activation
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The capacitive touch interface replaces mechanical buttons with an electrical sensing mechanism that detects changes in capacitance. This eliminates physical openings and gaps where fluids could penetrate, creating a sealed, fluid-resistant interface that prevents unintended activation while maintaining precise control through capacitive sensing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The transparent polymer overlay provides a continuous, sealed surface that prevents fluid penetration while integrating capacitive sensors for input detection. This film structure eliminates the need for mechanical button openings, creating a fluid-tight interface that resists harsh environmental conditions.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If traditional control interfaces are used, then the device can be manufactured with standard components, but the interface lacks durability in extreme conditions

Engineering Contradiction:
Improvecomponent availabilityVSAvoidinterface durability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent integrates capacitive sensors directly into a transparent polymer matrix, creating a composite material structure that combines the durability and environmental resistance of the polymer with the sensing capabilities of the capacitive elements. This integrated approach maintains manufacturing feasibility while dramatically improving interface durability in extreme temperatures, humidity, and chemical exposure.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent merges the structural polymer body with the capacitive sensing functionality into a single integrated interface layer. This combination eliminates the need for separate mechanical button components and their associated fasteners and seals, simplifying manufacturing while providing a durable, unified structure resistant to environmental degradation.

Inventive Principle:
Principle #5Merging (Combining)

4Adaptability or versatility

If physical buttons are used, then the interface provides discrete input options, but the input functionality is limited to specific button functions

Engineering Contradiction:
Improveinput functionalityVSAvoidinterface design
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The capacitive touch interface provides a universal input mechanism that can detect various interaction types (tap, slide, press duration, multi-touch patterns) across the entire surface. This single versatile interface replaces multiple discrete physical buttons, enabling diverse input functions without increasing mechanical complexity, while allowing the system to adapt to different operational modes through software interpretation of capacitive patterns.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution provides a durable, fluid-resistant, and compact user interface that is less prone to wear and tear, while allowing for intuitive and precise control of temperature settings through capacitive sensing, improving reliability and usability in harsh environments.

Implementation Method 1

The capacitive slider sensor is configured to be activated by proximity or contact of a conductor to a front surface of the body at an area overlapping the first input graphic

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP3987662B1Industrial control projective capacitive touch interface
Publication Date: 2024.04.10 WATLOW ELECTRIC MANUFACTURING CO
  • EP3987662B1 patent drawingFigure 1~2
  • EP3987662B1 patent drawingFigure 3~4
  • EP3987662B1 patent drawingFigure 5

AI summary

An industrial control device includes a display, a body, and a controller. The body includes a capacitive slider sensor, a graphic, and a window. The graphic overlaps the capacitive slider sensor. The window is transparent and aligned with the display to permit the display to be viewed through the window. The controller is coupled to an output of the capacitive slider sensor to receive signals from the capacitive slider sensor. The controller is coupled to the display and configured to control the display.