Capacitive Touch Panel Electrode Layout to Prevent Insulator Peeling

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Solution Overview

Problem

Capacitive-sensing-type touch panels face reliability issues due to stress-induced peeling of insulators from the substrate, leading to potential disconnection of connection electrodes and reduced device reliability.

Innovation Solution

The design incorporates first and second detection electrodes with rhombus shapes, strategically positioned first and second connection electrodes, and an insulator covered by both, reducing the likelihood of peeling and moisture absorption, and enhancing detection sensitivity by increasing electrostatic capacity changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the insulator is provided to cover the first connection electrode, then the insulation performance is improved, but the insulator may be peeled off from the substrate when stress is applied, reducing reliability

Engineering Contradiction:

Improveconnection reliabilityVSAvoidinsulator adhesion strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The insulator is designed with a curved side surface instead of a straight side surface. This curvature allows the insulator to flex and deform elastically when stress is applied during repeated push operations, preventing the insulator from peeling off the substrate while maintaining its insulation function

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The side surface shape parameter of the insulator is changed from straight to curved. This geometric parameter modification enables the insulator to accommodate stress through elastic deformation, resolving the contradiction between maintaining adhesion and providing insulation coverage

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the second connection electrode is provided above the insulator to connect adjacent second detection electrodes, then the detection functionality is improved, but the second connection electrode may be disconnected if the insulator peels off

Engineering Contradiction:

Improveelectrode connection reliabilityVSAvoidmulti-layer electrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The curved side surface of the insulator prevents peeling, which in turn prevents disconnection of the second connection electrode. The curvature design protects the underlying electrode structure from damage while maintaining the necessary electrical connections

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of manufacture

If the insulator has only straight side portions, then the manufacturing is simplified, but the insulator is more prone to peeling under stress

Engineering Contradiction:

Improveinsulator fabrication simplicityVSAvoidinsulator attachment reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The curved side surface design balances manufacturing feasibility with improved reliability. The curvature can be implemented through standard fabrication processes while significantly reducing peeling compared to straight-sided insulators

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

This configuration improves the reliability and detection sensitivity of the input device by minimizing insulator peeling and moisture absorption, while maintaining transparency and visibility for capacitive touch panels.

Implementation Method 1

the insulator has a convex curved surface within a region from an end to a top... a stress applied to the insulator is alleviated at the convex curved surface

Methodology Applied

Scientific EffectStress distribution through curved geometry:

Implementation Method 2

there is known a capacitive-sensing-type touch panel, which captures changes in electrostatic capacity between a finger and a detection electrode to detect the input location

Methodology Applied

Scientific EffectCapacitive sensing: Capacitance

Implementation Method 3

the insulator has a convex curved surface within a region from an end to a top... when the stress is given on the insulator, there is a possibility that the insulator is peeled off of the substrate... a stress applied to the insulator is alleviated at the convex curved surface

Methodology Applied

Scientific EffectStress alleviation through convex curved surface:

Data Source

PatentEP2541381B1Input device, display device, and portable terminal

Publication Date: 2017.09.06 KYOCERA CORP

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AI summary

The disclosed input device is provided with: a substrate; first detection electrodes provided on the substrate and arrayed along a first direction; second detection electrodes provided on the substrate and arrayed along a second direction; first connection electrodes that are provided on the substrate and that connect adjacent first detection electrodes; insulating bodies that are provided on the substrate in a manner so as to cover the first connection electrodes; and second connection electrodes that are provided on the insulating bodies in a manner so as to straddle said insulating bodies and that connect adjacent second detection electrodes. A portion of each first detection electrode is provided in a manner so as to cover a portion of an insulating body.