Piezo Touch Sensor Assembly for Metallic Panels to Prevent Oxidation

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Solution Overview

Problem

Conventional touch sensors face challenges when applied to metallic surfaces, including oxidation issues with metal connectors, difficulty in applying capacitive and resistive touch technologies due to rigidity, and manufacturing inefficiencies with separate elements requiring assembly on metallic panels, leading to incorrect operations and reduced productivity.

Innovation Solution

A touch sensor assembly for metallic panels that includes a touch substrate with piezo discs, holders, and a cover structure, using adhesive members with high insulation resistance and heat resistance to prevent oxidation and deformation, and a design that separates touch points to prevent incorrect operations, integrated with a display cover for improved aesthetics and functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a metal connector is exposed to air for a long time, then it may become oxidized, but this creates problems with electrical connection

Engineering Contradiction:
Improveexposure timeVSAvoidelectrical connection
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent introduces a non-conductive adhesive member as an intermediary between the metal connector and the external environment. This adhesive member prevents direct contact between the metal connector and air, thereby preventing oxidation while maintaining electrical connection integrity through the non-conductive barrier that still allows electrical function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a protected environment for the metal connector by enclosing it within the non-conductive adhesive member. This effectively isolates the metal connector from the reactive atmosphere (air), preventing oxidation without requiring the connector to be in an inert atmosphere in the traditional sense.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Ease of operation

If too much force is applied to the metal touch sensor, then the sensor responds, but force may be unintentionally delivered to another sensor causing incorrect operation

Engineering Contradiction:
Improvetouch sensitivityVSAvoidoperation accuracy
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent divides the touch sensing function into separate, isolated metal connectors that are physically separated and independently supported. Each connector responds only to localized force applied directly to it, preventing force transfer to adjacent sensors. This segmentation ensures that touch sensitivity is maintained while avoiding incorrect operations from unintended force delivery.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements localized support structures and adhesive member configurations for each metal connector, creating zones of independent mechanical response. Each connector has its own dedicated support and adhesive connection, ensuring that force applied to one connector remains localized and does not affect other sensors, thereby maintaining operation accuracy.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If the touch substrate and cover are manufactured as separate elements, then each can be optimized independently, but productivity is reduced due to separate attachment steps

Engineering Contradiction:
Improvedesign flexibilityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent merges the touch substrate and cover into a single integrated unit by using the non-conductive adhesive member to bond them together before final assembly. This integration allows both elements to be manufactured and optimized independently while being combined into one assembly, reducing the number of separate attachment steps and improving manufacturing productivity without sacrificing design flexibility.

Inventive Principle:
Principle #5Merging (Combining)

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, sensitive, and stable touch sensor assembly that prevents oxidation and deformation, ensures correct operation, and enhances manufacturing efficiency by integrating the touch sensor and display cover, offering long-lasting adhesion and improved user experience.

Implementation Method 1

using adhesive members with high insulation resistance and heat resistance to prevent oxidation and deformation

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

A touch sensor assembly for metallic panels that includes a touch substrate with piezo discs

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3605845B1Touch sensor assembly and refrigerator door including a touch sensor assembly
Publication Date: 2022.11.09 LG ELECTRONICS INC
  • EP3605845B1 patent drawingFigure 1
  • EP3605845B1 patent drawingFigure 2
  • EP3605845B1 patent drawingFigure 3

AI summary

A touch sensor assembly may include a touch substrate that is attached to a rear of a front panel on which touch points are displayed, a piezo disc in which a first pole and a second pole are stacked, wherein the first pole faces the touch substrate to contact a rear of the touch substrate; a holder that is configured to support a lateral surface and a rear of the piezo disc to fix the piezo disc to the rear of the touch substrate, and a cover that has a front surface which adheres to the rear of the touch substrate and that includes a concave chamber which is overlapped with the holder. A refrigerator door may include the touch sensor assembly.