Touch Integrated Display Device Thickness Reduction

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Solution Overview

Problem

Current touch integrated display devices face challenges in reducing thickness while maintaining touch performance, with existing solutions either increasing thickness due to additional layers or compromising on manufacturing costs and recognition performance.

Innovation Solution

A touch integrated display device is designed with a transistor on a lower substrate, a pixel electrode, a liquid crystal layer, a common electrode, and sensing electrodes on an upper substrate, where the driving and sensing electrodes are positioned on either side of the liquid crystal layer to minimize thickness and interference, utilizing a time division drive method to optimize touch recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the add-on type touch panel is attached on the display device, then the touch function is added, but the thickness is increased and visibility is reduced

Engineering Contradiction:
Improvetouch functionVSAvoidthickness
Core Design Contradiction:
Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent merges the touch panel structure with the display device structure by integrating the sensing electrode layer and driving electrode layer into the same substrate system. The sensing electrode layer is formed on the upper glass substrate while the driving electrode layer is formed on the lower glass substrate, creating a unified integrated structure that eliminates the need for separate add-on layers and reduces overall thickness.

Inventive Principle:
Principle #5Merging (Combining)

2Length of stationary object

If the on-cell type touch panel is formed on the upper glass substrate, then the thickness is reduced compared to add-on type, but the entire thickness is increased by driving electrode layer, sensing electrode layer, and insulation layer

Engineering Contradiction:
ImprovethicknessVSAvoidnumber of layers
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts the insulation layer requirement by using the liquid crystal layer itself as the insulating medium between the sensing electrode layer and driving electrode layer. This eliminates the need for a separate insulation layer, reducing the number of layers while maintaining the thin-film structure. The liquid crystal layer serves dual purposes: display function and electrical insulation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Length of stationary object

If the in-cell type touch panel is formed inside the display device, then the thickness is reduced, but the driving electrode and sensing electrode cause wirings and parasitic capacitance that lower touch recognition performance

Engineering Contradiction:
ImprovethicknessVSAvoidtouch recognition performance
Core Design Contradiction:
Length of stationary objectVSReliability

Solution Approach 1:

The patent positions the sensing electrode layer and driving electrode layer on opposite sides of the liquid crystal layer, utilizing the vertical dimension (z-axis) through the liquid crystal medium. This spatial separation in the third dimension minimizes parasitic capacitance between electrodes while maintaining a compact thin-film structure, thereby improving touch recognition performance without increasing thickness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 the overall thickness of the display device, enhances visibility by minimizing parasitic capacitance, and improves touch recognition performance while maintaining display quality.

Implementation Method 1

a liquid crystal layer positioned on the common electrode

Methodology Applied
Scientific EffectLiquid crystal effect: Liquid Crystals

Implementation Method 2

a sensing electrode which is positioned on the other side of the upper substrate and faces the driving electrode

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP2492783B1Touch integrated display device
Publication Date: 2018.09.26 LG DISPLAY CO LTD
  • EP2492783B1 patent drawingFigure 1
  • EP2492783B1 patent drawingFigure 2a
  • EP2492783B1 patent drawingFigure 2b

AI summary

The present invention provides a touch integrated display device which reduces a thickness of a display device and can improve touch performance. The touch integrated display device according to one embodiment of the present invention can include: a transistor positioned on a lower substrate; a pixel electrode (340a) connected to the transistor; a common electrode (335) facing the pixel electrode (340a); a liquid crystal layer (549) positioned on the common electrode (335); an upper substrate (350, 550) facing the lower substrate which is positioned at both sides of the liquid crystal layer (549); a driving electrode (380, 580) which is positioned on one side of the upper substrate (350, 550) adjacent to the liquid crystal layer (549); and a sensing electrode (390, 590) which is positioned on the other side of the upper substrate (350, 550) and faces the driving electrode (380, 580).