Touch Sensor Composite Electrode Design for Display Devices

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Solution Overview

Problem

Modern display devices with touch sensors face increased power consumption and RC delay due to high resistance in electrode portions, which affects the performance of touchscreens in various devices.

Innovation Solution

A touch sensor design is implemented with a first transparent conductive layer, a touch insulating layer, and a second transparent conductive layer, including sub-sensing electrodes and dummy electrodes, to reduce resistance while maintaining light transmittance, using amorphous indium tin oxide and opaque conductive materials to lower overall resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If transparent conductive materials are used in touch sensor electrodes, then light transmittance is maintained, but resistance increases causing higher power consumption and RC delay

Engineering Contradiction:

Improvelight transmittanceVSAvoidpower consumption

Core Design Contradiction:

Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent employs a composite electrode structure combining transparent conductive materials (first and second touch conductive layers) with opaque conductive materials (connecting portions and dummy electrodes). This composite approach allows the electrode to maintain light transmittance in the sensing area while reducing overall resistance through the opaque conductive components, thereby lowering power consumption without sacrificing optical performance.

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If transparent conductive materials are used in touch sensor electrodes, then light transmittance is maintained, but RC delay occurs due to high resistance

Engineering Contradiction:

Improvelight transmittanceVSAvoidRC delay

Core Design Contradiction:

Illumination intensityVSLoss of time

Solution Approach 1:

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The electrode is segmented into multiple functional components: first and second touch conductive layers for light transmittance, connecting portions for electrical connection, and dummy electrodes for resistance reduction. This segmentation allows each component to perform its specific function optimally, reducing overall RC delay while maintaining transparency where needed.

Inventive Principle:

Principle #1Segmentation

3Use of energy by moving object

If electrode resistance is reduced to lower power consumption, then material quantity or electrode area must be increased, but this affects light transmittance

Engineering Contradiction:

Improvepower consumptionVSAvoidlight transmittance

Core Design Contradiction:

Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent applies local quality by using opaque conductive materials (connecting portions and dummy electrodes) specifically in non-sensing areas where light transmittance is not required, while maintaining transparent conductive materials in the sensing area. This localized approach allows resistance reduction through increased material quantity in specific regions without affecting the overall light transmittance of the touch sensor.

Inventive Principle:

Principle #3Local quality

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 effectively reduces the resistance of electrode portions, thereby decreasing power consumption and minimizing RC delay, enhancing the performance and efficiency of touchscreens in display devices.

Implementation Method 1

A first touch conductive layer which is disposed on the second substrate and includes a first transparent conductive material, and a second touch conductive layer which is disposed on the touch insulating layer and includes a second transparent conductive material

Methodology Applied

Scientific EffectElectrical Conduction: Conduction (electrical)

Implementation Method 2

a touch insulating layer disposed on the first touch conductive layer

Methodology Applied

Scientific EffectElectrical Insulation: Dielectric

Data Source

PatentUS11204660B2Touch sensor and display device including the same

Publication Date: 2021.12.21 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a first substrate, light emitting elements, a second substrate, and a touch sensor on the second substrate. The touch sensor includes a first touch conductive layer on the second substrate, a touch insulating layer on the first touch conductive layer, and a second touch conductive layer on the touch insulating layer. The first touch conductive layer includes first sub-sensing electrodes, a connecting portion connecting the first sub-sensing electrodes adjacent to each other, and second sub-sensing electrodes. The second touch conductive layer includes a third sub-sensing electrode connected to one of the first sub-sensing electrodes through contact holes passing through the touch insulating layer, and a fourth sub-sensing electrode electrically connected to one of the second sub-sensing electrodes through contact holes passing through the touch insulating layer electrically connecting the second sub-sensing electrodes adjacent to each other.