In-Cell Touch Display Electrode Fabrication Process

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Solution Overview

Problem

The high manufacturing cost and long manufacturing time associated with forming a touch sensing electrode in in-cell type display devices, which decreases product competitiveness and increases the complexity of the manufacturing process.

Innovation Solution

A touch screen panel-integrated display device and method that reduces detailed processes by forming a thin-film transistor, protective layers, and electrodes on a substrate, with signal lines formed using a photomask to connect source or drain electrodes to pixel electrodes, allowing for a simpler and more efficient fabrication process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a touch sensing electrode is formed in in-cell type display devices through detailed processes, then touch sensing capability is achieved, but manufacturing cost increases and manufacturing time extends

Engineering Contradiction:
Improvetouch sensing capabilityVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines the touch sensing electrode formation process with the existing display device manufacturing process. The touch sensing electrode is integrated into the same manufacturing sequence as the display electrodes, using shared process steps such as ITO layer deposition and photomask patterning. This merging eliminates separate touch electrode manufacturing steps, thereby reducing manufacturing cost and time while maintaining touch sensing functionality.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If detailed processes are used to form touch sensing electrode, then touch sensing capability is achieved, but the complexity of manufacturing process increases

Engineering Contradiction:
Improvetouch sensing capabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal manufacturing process where the same ITO layer and photomask steps serve dual purposes: forming both display electrodes and touch sensing electrodes. The common electrode functions as both a display component and a touch sensing element. This multi-functionality approach eliminates the need for separate specialized processes for touch electrode formation, thereby reducing manufacturing process complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3179346B1Touch screen panel-integrated display device and method for fabricating the same
Publication Date: 2023.02.15 LG DISPLAY CO LTD
  • EP3179346B1 patent drawingFigure 1
  • EP3179346B1 patent drawingFigure 2
  • EP3179346B1 patent drawingFigure 3

AI summary

There are provided a display device and a method for fabricating the display device including: a thin-film transistor located in each pixel defined by intersection between a gate line located in a first direction and a data line located in a second direction on a substrate; a first protective layer which is located on the thin-film transistor and in which a first contact hole is formed; a first electrode including a first layer connected to one of a source electrode or a drain electrode of the thin-film transistor through the first contact hole and a second layer located on the first layer and in the first contact hole; a signal line including a first signal line layer formed on the first protective layer of the same material on the same layer as the first layer of the first electrode and a second signal line layer formed on the first signal line layer of the same material on the same layer as the second layer of the first electrode; and a second electrode located on a different layer from the first electrode.