Layered Impedance Structure for Touch Display Sensitivity and ESD

Solution Overview

Problem

Existing touch display panels face issues with touch sensitivity and electrostatic interference due to reactions between the impedance layer and the polarizer, leading to reduced touch effect and precision.

Innovation Solution

A multilayer impedance structure is introduced, with a first impedance layer having a higher sheet resistance than a second impedance layer, positioned between the touch display panel and the polarizer, to ensure stable touch signals and electrostatic conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single impedance layer is used between the touch display panel and polarizer, then the device complexity is reduced, but the touch sensitivity and electrostatic conduction performance deteriorate

Engineering Contradiction:

Improvetouch sensitivityVSAvoidimpedance structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The impedance structure is divided into two distinct impedance layers with different sheet resistance values. The first impedance layer has a first sheet resistance and the second impedance layer has a second sheet resistance, where the ratio between them falls within a specific range. This segmentation allows each layer to perform different functions: one layer primarily conducts electrostatic charges while the other maintains touch signal integrity, thereby resolving the contradiction between touch sensitivity and electrostatic conduction that cannot be achieved with a single impedance layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the impedance structure are assigned different electrical properties through the use of layers with distinct sheet resistance values. The first impedance layer is designed with specific electrical characteristics optimized for electrostatic conduction, while the second impedance layer is designed with characteristics optimized for touch signal transmission. This local differentiation of properties enables simultaneous optimization of both touch sensitivity and electrostatic interference reduction without requiring a single complex material.

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If the sheet resistance of the impedance layer is increased to reduce electrostatic interference, then the electrostatic conduction improves, but the touch signal transmission deteriorates

Engineering Contradiction:

Improveelectrostatic interferenceVSAvoidtouch signal transmission

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The impedance structure is divided into two distinct impedance layers with different sheet resistance values. The first impedance layer has a first sheet resistance and the second impedance layer has a second sheet resistance, where the ratio between them falls within a specific range. This segmentation allows each layer to perform different functions: one layer primarily conducts electrostatic charges while the other maintains touch signal integrity, thereby resolving the contradiction between touch sensitivity and electrostatic conduction that cannot be achieved with a single impedance layer.

Inventive Principle:

Principle #1Segmentation

3Reliability

If a multilayer impedance structure with different sheet resistances is used, then the touch sensitivity and electrostatic conduction are improved, but the manufacturing process complexity increases

Engineering Contradiction:

Improvetouch effectVSAvoidimpedance structure fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies that the ratio between the first sheet resistance and the second sheet resistance should fall within a particular range. By defining this parameter range, the invention provides clear manufacturing guidelines that enable consistent production of the multilayer impedance structure. This parameter control approach transforms the manufacturing challenge into a manageable process by establishing quantitative criteria for layer resistance ratios, thereby facilitating standardized fabrication while maintaining the performance benefits of the multilayer design.

Inventive Principle:

Principle #35Parameter changes

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

The multilayer impedance structure enhances touch sensitivity and precision while reducing electrostatic interference, ensuring stable operation and improved display effects.

Implementation Method 1

a sheet resistance of the first impedance layer is greater than a sheet resistance of a second impedance layer

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS12373075B2Touch display module and touch display device

Publication Date: 2025.07.29 XIAMEN TIANMA MICRO ELECTRONICS

AI summary

Provided are a touch display module and a touch display device. The touch display module includes a touch display panel and an impedance structure and a polarizer that are sequentially disposed on a light emission side of the touch display panel. The impedance structure includes a first impedance layer and a second impedance layer. The first impedance layer is located on a side of the second impedance layer facing away from the touch display panel. A sheet resistance of the first impedance layer is greater than a sheet resistance of the second impedance layer.