Non-Transparent Bridge Lines for Touch Display Panels

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Solution Overview

Problem

Conventional touch panels face challenges with low touch sensitivity due to high resistance in transparent conductive materials and frequent breakages of metallic bridge lines, which also reduce the aperture ratio and yield of touch display panels.

Innovation Solution

The use of non-transparent bridge lines with high electrical conductivity, disposed between transparent sensing pads, which are partially overlapping and electrically connected, to improve touch sensitivity while maintaining a negligible impact on the aperture ratio by adjusting their line width between 0.5 micrometers and 10 micrometers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If transparent conductive material is used for sensing pads, then transparency is maintained, but resistance increases causing low touch sensitivity

Engineering Contradiction:

ImprovetransparencyVSAvoidtouch sensitivity

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent uses a composite structure combining transparent conductive material (for transparency) with metallic bridge lines (for low resistance). The transparent sensing pads maintain optical properties while the metallic bridge lines provide excellent electrical conductivity to reduce overall resistance and improve touch sensitivity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The conductive path is segmented into two parts: transparent sensing pads that maintain optical properties and metallic bridge lines that provide low resistance. This segmentation allows each component to optimize its specific function - transparency for the pads and electrical conductivity for the bridge lines.

Inventive Principle:

Principle #1Segmentation

2Reliability

If metallic bridge lines are used to reduce resistance, then touch sensitivity improves, but aperture ratio decreases due to non-transparent material

Engineering Contradiction:

Improvetouch sensitivityVSAvoidaperture ratio

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The metallic bridge lines are strategically placed only where needed for electrical connection between sensing pads, rather than covering the entire display area. This localized application minimizes the impact on aperture ratio while providing the necessary low-resistance path for touch sensitivity.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bridge lines use partial action by being confined to specific connection regions rather than spanning the entire display. This partial coverage approach provides sufficient electrical connectivity without excessively reducing the aperture ratio, finding an optimal balance between the two requirements.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If metallic bridge lines are used for connection, then electrical conductivity improves, but line breakages occur during etching reducing yield

Engineering Contradiction:

Improveelectrical conductivityVSAvoidyield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent designs the metallic bridge lines with sufficient width (0.5-10 micrometers) and proper structural support beforehand to cushion against etching variations. This preventive design approach accounts for potential etching over-removal and prevents line breakages, thereby maintaining high electrical conductivity and improving manufacturing yield.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 solution enhances touch sensitivity and reduces the risk of line breakages during the etching process, ensuring higher yields and minimizing the noticeable effect of bridge lines on the display panel's aperture ratio.

Implementation Method 1

non-transparent bridge lines of a high electrical conductivity electrically connected to transparent conductive pads

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

at least one of the first transparent sensing pads forms a capacitor with the input device and at least one of the second transparent sensing pads forms another capacitor with the input device

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS9030434B2Touch display panel and touch sensing unit thereof

Publication Date: 2015.05.12 AU OPTRONICS CORP

AI summary

A touch display panel includes a display panel and a touch sensing unit. The touch sensing unit includes first sensing series, and second sensing series. Each of the first sensing series includes a plurality of first transparent sensing pads and a plurality of non-transparent bridge lines disposed along a first direction. Each of the non-transparent bridge lines is disposed between two adjacent first transparent sensing pads, overlapping with two adjacent first transparent sensing pads, and electrically connected to two adjacent first transparent sensing pads. The line width of each non-transparent bridge line is substantially between 0.5 micrometers and 10 micrometers, and the reduction of aperture ratio in a pixel region of the touch display panel caused by the non-transparent bridge lines is substantially between 0.1% and 5%. Each non-transparent bridge line and the long axis of each sub-pixel region are disposed in a non-parallel manner with each other.