Touch Electrode Positioning for Array Substrate Capacitance Balance

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Solution Overview

Problem

The existing touch display panels experience a significant difference in coupling capacitances between pixel electrodes and signal lines due to the placement of touch electrodes, leading to poor image display quality.

Innovation Solution

The array substrate design includes a touch electrode positioned between the outer edges of the pixel electrode, ensuring it does not interfere with signal lines, thereby maintaining equal distances and reducing coupling capacitance differences between the pixel electrode and signal lines on both sides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the touch electrode is placed between the pixel electrode and signal line to improve touch detection accuracy, then touch detection accuracy is improved, but the coupling capacitance difference between pixel electrode and signal lines increases

Engineering Contradiction:
Improvetouch detection accuracyVSAvoidimage display quality
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The touch electrode is designed with asymmetric positioning relative to the pixel electrode, specifically placed closer to the center of the pixel electrode rather than equidistant from signal lines. This asymmetric arrangement allows the touch electrode to effectively detect touch inputs while minimizing its interference on the coupling capacitance between the pixel electrode and signal lines, thereby resolving the contradiction between touch detection accuracy and image display quality

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The touch electrode is extended in the first direction (horizontal direction) to span across multiple sub-pixels, changing its dimensional footprint. This extension allows the touch electrode to maintain effective touch detection capability across a broader area while distributing its capacitive influence more evenly, reducing the coupling capacitance difference with signal lines and improving image display quality

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

2Area of stationary object

If the touch electrode is extended to improve touch detection coverage, then touch detection coverage is improved, but the coupling capacitance difference with signal lines increases

Engineering Contradiction:
Improvetouch detection coverageVSAvoidimage display quality
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The touch electrode is extended in the first direction (horizontal direction) to span across multiple sub-pixels, changing its dimensional footprint. This extension allows the touch electrode to maintain effective touch detection capability across a broader area while distributing its capacitive influence more evenly, reducing the coupling capacitance difference with signal lines and improving image display quality

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

Data Source

PatentEP3690617B1Array substrate, manufacturing method therefor, and touch display panel
Publication Date: 2023.11.22 BOE TECHNOLOGY GROUP CO LTD
  • EP3690617B1 patent drawingFigure 1A~1B
  • EP3690617B1 patent drawingFigure 2A
  • EP3690617B1 patent drawingFigure 2B~3A

AI summary

An array substrate, a manufacturing method therefor, and a touch display panel. The array substrate comprises: a touch electrode (32), located on a base substrate (31) and extending along a first direction; a pixel electrode (90), located on the base substrate (31), insulated from the touch electrode (32) and comprising opposing outer edges (90A, 90B), the outer edges (90A, 90B) being sequentially arranged along a second direction. On the second direction, the orthographic projection of the touch electrode (32) on the base substrate (31) is located between the orthographic projections of the outer edges (90A, 90B) of the pixel electrode (90) on the base substrate (31). The array substrate prevents or reduces differences between coupling capacitances between the pixel electrode (90) and signal lines (330) on two sides thereof.