Active Matrix Substrate Layout for Low-Capacitance In-Cell Touch

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Solution Overview

Problem

Existing display panels with in-cell touch sensors face challenges in improving touch sensor performance, display quality, and reducing costs while maintaining high functionality.

Innovation Solution

The active matrix substrate incorporates a first insulating layer made of an organic resin film between the touch sensor line and the common electrode, reducing parasitic capacitance and load capacitance, and includes a protruding portion for improved structural strength and sensing uniformity, with a simplified manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an inorganic insulating film is used between the touch sensor line and common electrode, then insulation performance is improved, but parasitic capacitance increases and touch sensor performance deteriorates

Engineering Contradiction:

Improveinsulation performanceVSAvoidparasitic capacitance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the material parameter of the insulating layer from inorganic material to organic resin material. This material substitution fundamentally alters the dielectric properties, reducing the dielectric constant and thereby decreasing parasitic capacitance between the touch sensor line and common electrode, while still maintaining adequate insulation performance for the display panel operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure where the organic resin film is combined with other layers (such as the protruding portion structure and surrounding insulating layers) to achieve both insulation and low-capacitance requirements. This composite approach allows optimization of each layer's function while achieving overall system performance.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If the distance between touch sensor line and common electrode is increased to reduce parasitic capacitance, then touch sensor performance is improved, but the space for pixel electrode is reduced

Engineering Contradiction:

Improveparasitic capacitanceVSAvoidpixel aperture ratio

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

Instead of changing the geometric distance parameter, the patent changes the material parameter (dielectric constant) of the insulating layer. This allows maintaining the original compact spacing between touch sensor line and common electrode while achieving reduced parasitic capacitance through the use of organic resin material with lower dielectric properties.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different material properties locally at the interface between touch sensor line and common electrode. The organic resin film is specifically positioned in this critical region where capacitance reduction is most needed, while other regions maintain their original structure to preserve pixel aperture ratio.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If multiple insulating layers are added to improve touch sensor performance, then sensing uniformity is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvesensing uniformityVSAvoidnumber of layers

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The organic resin film serves multiple functions simultaneously: it provides electrical insulation between conductive layers, reduces parasitic capacitance due to its low dielectric constant, and the protruding portion configuration improves sensing uniformity. By combining these functions in a single layer design, the patent avoids adding multiple separate layers, thereby maintaining manufacturing simplicity while achieving improved touch sensor performance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enhances touch performance, reduces uneven sensing, and lowers manufacturing costs by minimizing parasitic capacitance and simplifying the production process.

Implementation Method 1

The first insulating layer is formed of an organic resin film... reducing parasitic capacitance and load capacitance

Methodology Applied

Scientific EffectParasitic capacitance reduction: Capacitance

Data Source

PatentUS12547280B2Active matrix substrate, display panel with touch sensor function, and method of manufacturing active matrix substrate

Publication Date: 2026.02.10 SHARP DISPLAY TECHNOLOGY CORP

AI summary

An active matrix substrate is to be mounted on a display panel with a touch sensor function. The active matrix substrate includes a first layer provided with a touch sensor line, a second layer being above the touch sensor line and being provided with a pixel electrode, and a common electrode as a third layer formed between the first layer and the second layer. The common electrode functions as a touch sensor electrode by being connected to the touch sensor line and also functions as a counter electrode of the pixel electrode. The active matrix substrate further includes a first insulating layer formed between the first layer and the third layer, and a second insulating layer formed between the second layer and the third layer. The first insulating layer is formed of an organic resin film.