Integrated Touch Display Common Electrode Design

Solution Overview

Problem

Existing touch sensor integrated type display devices face challenges with increased thickness due to separate touch driving and sensing electrodes, leading to reduced visibility and sensitivity, as well as increased parasitic electrostatic capacitance.

Innovation Solution

The integration of common electrodes serving as both touch driving and sensing electrodes, with a passivation layer shielding the electric field, and a column spacer design that reduces the amount of liquid crystals between the touch sensing and driving electrodes, allowing for a thinner display device with reduced electrostatic capacitance changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate touch driving and sensing electrodes are used, then touch sensor functionality is achieved, but device thickness increases

Engineering Contradiction:

Improvetouch sensor functionalityVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent combines the touch driving electrode and touch sensing electrode into a single integrated electrode structure. The common electrode serves dual functions as both driving and sensing electrode, eliminating the need for separate electrode layers and thereby reducing device thickness while maintaining touch sensor functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The common electrode is designed to perform multiple functions simultaneously - it acts as both the touch driving electrode and the touch sensing electrode. This multi-functional design allows the device to achieve touch sensor capabilities without requiring separate dedicated electrode structures for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate touch driving and sensing electrodes are used, then touch sensor functionality is achieved, but touch sensitivity decreases

Engineering Contradiction:

Improvetouch sensor functionalityVSAvoidtouch sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

By merging the driving and sensing electrodes into a single common electrode structure, the patent reduces the overall electrode thickness and minimizes the distance between electrodes. This improves the coupling between electrodes and enhances touch sensitivity while maintaining full touch sensor functionality.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If separate touch driving and sensing electrodes are used, then touch sensor functionality is achieved, but parasitic electrostatic capacitance increases

Engineering Contradiction:

Improvetouch sensor functionalityVSAvoidparasitic electrostatic capacitance

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The integration of driving and sensing electrodes into a single common electrode reduces the total electrode area and minimizes overlapping regions between separate electrodes. This structural consolidation directly reduces parasitic electrostatic capacitance while preserving the essential touch sensor functionality.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If more electrode layers are added, then touch sensor functionality is improved, but device thickness increases

Engineering Contradiction:

Improvetouch sensor functionalityVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The common electrode is designed to perform multiple functions simultaneously - it acts as both the touch driving electrode and the touch sensing electrode. This multi-functional design allows the device to achieve touch sensor capabilities without requiring separate dedicated electrode structures for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the touch driving electrode and touch sensing electrode into a single integrated electrode structure. The common electrode serves dual functions as both driving and sensing electrode, eliminating the need for separate electrode layers and thereby reducing device thickness while maintaining touch sensor functionality.

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

This solution enables a thinner display device with enhanced touch sensitivity by eliminating the need for separate touch electrodes and reducing the amount of liquid crystals, thereby minimizing changes in electrostatic capacitance, thus improving user interaction and device performance.

Implementation Method 1

a first passivation layer that covers the thin film transistors and exposes a portion of the gate insulating film

Methodology Applied

Scientific EffectElectrostatic shielding: Faraday Cage

Implementation Method 2

a column spacer that is formed on the black matrix and maintains a cell gap between the thin film transistor array and the color filter array

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 3

a liquid crystal layer interposed between the color filter array and the thin film transistor array

Methodology Applied

Scientific EffectLiquid crystal electro-optic effect: Liquid Crystals

Implementation Method 4

capable of recognizing a user's touch by applying a touch driving voltage to a plurality of touch driving electrodes Tx and detecting a change in electrostatic capacitance between the touch driving electrodes Tx and a plurality of touch sensing electrodes Rx

Methodology Applied

Scientific EffectElectrostatic capacitance change: Capacitance

Data Source

PatentUS9250756B2Touch sensor integrated type display device comprising a plurality of first and second electrodes

Publication Date: 2016.02.02 LG DISPLAY CO LTD

AI summary

A touch sensor integrated type display device includes gate lines, a gate insulating film, data lines formed to cross over the gate lines, thin film transistors formed in pixel regions, a first passivation layer that covers the thin film transistors, first electrodes disposed on the first passivation layer along the data lines with the gate lines interposed therebetween, a second passivation layer covering the first electrodes, pixel electrodes that are formed in the pixel regions to partially overlap the first electrodes, and second electrodes formed on the second passivation layer in parallel with the gate lines, each of the plurality of second electrodes is disposed between neighboring pixel electrodes with the gate lines interposed therebetween.