Piezo Touch Sensor Assembly With Curved Wiring for Metal Panels

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Solution Overview

Problem

Conventional touch sensors face challenges in reliably detecting touch operations on metal surfaces, particularly when subjected to repeated use, leading to potential damage and disconnection of electrical signals, which affects the durability and reliability of the sensor.

Innovation Solution

A touch sensor assembly featuring a piezo disk with first and second poles, a flexible pressing part, and a holder with conductive materials, where the piezo disk is fixed to a touch substrate with leg parts and wirings forming a curved shape to enhance durability and prevent signal disconnection, combined with an oxidation prevention film to prevent electrical contact failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional touch sensing method is applied to a metal panel, then the button can be implemented on the panel, but the electrical signal pattern may be disconnected due to repeated use and fatigue accumulation

Engineering Contradiction:
Improvetouch operation capabilityVSAvoidsignal connection reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The wiring pattern is designed in a curved shape rather than a straight line to increase the withstanding load and prevent disconnection. The curved wiring can better accommodate the deformation and stress caused by repeated pressing operations, thereby maintaining signal connection reliability over time.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent changes the physical parameters of the wiring by forming it in a curved geometry with increased path length and flexibility. This parameter change allows the wiring to absorb mechanical stress and deformation from repeated use, preventing signal disconnection while maintaining touch operation capability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If force is applied repeatedly to a pressing portion on a metal panel, then touch operation can be performed, but the pressing portion and periphery may be damaged with time

Engineering Contradiction:
Improvebutton pressing functionalityVSAvoidpressing portion durability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

A flexible pressing portion is provided on the touch substrate, allowing it to deform under pressure and return to its original shape. This flexibility enables repeated pressing operations without permanent damage to the pressing portion or its periphery, maintaining both operational ease and structural strength.

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of manufacture

If a straight line wiring pattern is used to connect electrical signals, then the manufacturing is simple, but the withstanding load is reduced compared to a curved line

Engineering Contradiction:
Improvewiring pattern fabricationVSAvoidwiring load withstanding capability
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The wiring is designed in a curved shape that provides better mechanical strength and load withstanding capability compared to a straight line. The curved geometry distributes stress more effectively, allowing the wiring to withstand repeated deformation from touch operations while remaining manufacturable through standard PCB or flexible circuit techniques.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 reliable touch operation sensing, increased durability, and extended lifespan by preventing signal disconnection and reducing the risk of damage, while maintaining high sensitivity and design flexibility.

Implementation Method 1

a piezo disk having first and second poles stacked on a front surface of the touch substrate

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3745595B1Touch sensor assembly
Publication Date: 2022.10.19 LG ELECTRONICS INC
  • EP3745595B1 patent drawingFigure 1
  • EP3745595B1 patent drawingFigure 2
  • EP3745595B1 patent drawingFigure 3

AI summary

A touch sensor assembly includes a touch substrate attached to a rear surface of a panel having a touch point, a piezo disk having first and second poles stacked thereon, wherein the first pole is disposed on at least a central portion of a front surface thereof and aligned in a direction facing the touch substrate to be fixed to a rear surface of the touch substrate, a pressing part flexibly provided on the touch substrate, electrically connected to the first pole upon being in contact with the first pole, and electrically connected to a plurality of wirings provided on the touch substrate at a plurality of points, and a fixing surface electrically connected to the second pole while supporting the second pole such that the piezo disk is fixed to the rear surface of the touch substrate and electrically connected to second wirings provided on the touch substrate.