Embedded Touch Screen Common Electrode Segmentation

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Solution Overview

Problem

Conventional in-cell touch screens exhibit abnormal liquid crystal molecule rotation and brightness inconsistencies in areas shielded by the black matrix, leading to display issues like bright or dark line patterns when viewed from large angles due to the absence of a common electrode in these areas.

Innovation Solution

The in-cell touch screen design includes a color filter substrate with a black matrix and an array substrate featuring common electrode plates, sensing electrode sub-wires, and pixel sub-electrodes, where metal vias are used to connect these elements, forming electric fields that drive liquid crystal molecules to tilt consistently, thereby normalizing display effects in shielding areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the black matrix shields scan lines and data lines in the array substrate, then the shielding effect is improved, but liquid crystal molecules in the shielding area rotate abnormally causing brightness inconsistency and display defects

Engineering Contradiction:
Improveshielding effectVSAvoiddisplay quality
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces sensing electrode sub-wires as intermediary elements positioned between the black matrix shielding area and the common electrode. These sub-wires extend into the shielding area to provide electrical connection and maintain electric field distribution, acting as a mediator that allows the shielding function to work while preventing abnormal liquid crystal rotation. The sub-wires bridge the gap between the shielding structure and the electrode system, ensuring both shielding effectiveness and display quality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If no common electrode is present in the shielding area corresponding to the black matrix, then the black matrix can effectively shield light, but liquid crystal molecules flip abnormally leading to bright or dark line patterns

Engineering Contradiction:
Improvelight shieldingVSAvoidliquid crystal orientation
Core Design Contradiction:
Illumination intensityVSShape

Solution Approach 1:

The patent segments the common electrode into common electrode plates with gaps between them. The sensing electrode sub-wires are positioned in these gaps and extend into the shielding area. This segmentation allows the common electrode to maintain its light-shielding compatibility while the sub-wires fill the electrical field gap in the shielding area, preventing abnormal liquid crystal orientation without compromising the black matrix shielding function.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If the black matrix uses wider horizontal light shielding strips to shield scan lines, then scan line shielding is improved, but vertical areas show brighter line patterns due to insufficient electrode coverage

Engineering Contradiction:
Improvescan line shieldingVSAvoidvertical line brightness
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent applies local quality by making the sensing electrode sub-wires specifically positioned in vertical gap regions where the black matrix provides shielding. The sub-wires have extended length in the vertical direction to ensure adequate electrical field coverage in these specific areas. This localized enhancement ensures that vertical shielding areas maintain proper liquid crystal orientation and consistent brightness, while the horizontal shielding strips can maintain their wider design for effective scan line shielding.

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

This configuration ensures that liquid crystal molecules in shielding areas rotate normally, eliminating brightness inconsistencies and preventing the appearance of bright or dark line patterns when viewed from large angles, thus enhancing the display quality.

Implementation Method 1

a common electrode layer, wherein a patterning process is performed on the common electrode layer to form a number of common electrode plates distributed in an array... the sensing electrode wires are connected with the common electrode plates... forming electric fields that drive liquid crystal molecules to tilt consistently

Methodology Applied
Scientific EffectElectric field: Electric Field

Implementation Method 2

enables liquid crystal molecules corresponding to a shielding area of a black matrix to rotate normally so as to have a normal display effect in the area

Methodology Applied
Scientific EffectLiquid crystal rotation: Liquid Crystals

Data Source

PatentEP3647864B1Embedded touch screen
Publication Date: 2023.05.03 WUHAN CHINA STAR OPTOELECTRONICS TECH CO LTD
  • EP3647864B1 patent drawingFigure 1~2
  • EP3647864B1 patent drawingFigure 3

AI summary

An embedded touch screen, comprising an array substrate; a metal (219, 319) is added in a gap between common electrode plates (214, 314) of the array substrate; the metal (219, 319) is connected to the common electrode plates (214, 314) and forms, together with pixel electrodes (221, 321), an electric field, so as to drive liquid crystal molecules in a region corresponding to the gap of the common electrode plates to be flipped normally, such that the region has the same display effect as other display regions.