Touch Screen Power Electrode Openings for Parasitic Capacitance Control

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Solution Overview

Problem

Existing touch screens in display apparatuses suffer from defects due to malfunctions, which reduce their sensitivity and overall performance.

Innovation Solution

The display apparatus incorporates a touch screen design where the power supply electrodes have specific openings that overlap the touch routing lines, ensuring equal areas of overlap and regulating parasitic capacitance, thereby reducing defects and enhancing sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If power supply electrodes are placed close to touch routing lines to reduce area, then area is reduced, but parasitic capacitance increases causing touch screen malfunctions

Engineering Contradiction:
Improvearea occupied by power supply electrodesVSAvoidtouch screen sensitivity
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The power supply electrode is divided into multiple segments with openings between them, allowing touch routing lines to pass through. This segmentation reduces the continuous area of the power supply electrode while maintaining electrical connection, thereby reducing parasitic capacitance with touch routing lines and improving touch screen sensitivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power supply electrode structure is made non-uniform by introducing openings at specific locations where touch routing lines are present. This local modification reduces parasitic capacitance in critical areas while maintaining power supply function in other areas, resolving the contradiction between area reduction and reliability maintenance.

Inventive Principle:
Principle #3Local quality

2Device complexity

If power supply electrodes are placed overlapping touch routing lines to simplify layout, then layout complexity is reduced, but parasitic capacitance causes touch recognition degradation

Engineering Contradiction:
Improvelayout complexityVSAvoidtouch recognition sensitivity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

By segmenting the power supply electrode into multiple parts with openings, the electrode can overlap touch routing lines in the plan view without creating continuous parasitic capacitance. The openings break the capacitance path while maintaining the simplified overlapping layout, thus reducing touch recognition degradation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The openings in the power supply electrode act as an intermediary structure that allows the electrode to coexist with touch routing lines in the same area. These openings reduce the parasitic capacitance interaction while maintaining the simplified layout arrangement, resolving the contradiction between layout simplicity and touch recognition performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces defects caused by touch screen malfunctions and improves sensitivity by maintaining uniform parasitic capacitance between the touch routing lines and the power supply electrodes.

Implementation Method 1

the areas of the first openings of the first power supply electrode overlapping each of the plurality of first touch routing lines may be equal and/or when the second power supply electrode includes a plurality of second openings overlapping the plurality of second touch routing lines areas of the second openings of the second power supply electrode overlapping each of the plurality of second touch routing lines may be equal (see claim 5) which has the advantage to regulate the magnitudes of parasitic capacitance formed therebetween

Methodology Applied
Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentEP3495929B1Display apparatus having touch screen
Publication Date: 2025.04.30 LG DISPLAY CO LTD
  • EP3495929B1 patent drawingFigure 1
  • EP3495929B1 patent drawingFigure 2
  • EP3495929B1 patent drawingFigure 3

AI summary

An electroluminescence display apparatus having a touch screen (TS) includes a display panel including pixels (P) disposed in a display area (DA), a first power supply electrode (VDLa, VDLb) positioned in a non-display area (NDA) outside the display area (DA) and supplying first power to the pixels (P), and a second power supply electrode (VSLa, VSLb) supplying second power to the pixels (P), a plurality of first and second touch electrodes (Tx1 to Tx6; Rx1 to Rx4) disposed in the display area (DA) and disposed to cross over each other and to be electrically insulated from each other, a plurality of first touch routing lines (TW1 to TW6) disposed in the non-display area (NDA) and respectively connected to the first touch electrodes (Txl to Tx6), and a plurality of second touch routing lines (RW1 to RW4) disposed in the non-display area (NDA) and respectively connected to the second touch electrodes (Rx1 to Rx4), wherein at least one of the first and second power supply electrodes (VDLa, VDLb; VSLa, VSLb) includes a plurality of first openings (OP) overlapping the plurality of first touch routing lines (TW1 to TW6).