Touch Sensor Nanowire Overlap Stability Narrow Bezel

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Solution Overview

Problem

Touch sensors with metal nanomaterials face challenges in overlapping stability and surface resistance, particularly in narrow bezel products, due to higher surface resistance and alignment tolerance errors in conventional designs.

Innovation Solution

A touch sensor design featuring a substrate with a metal nanowire layer and a metal layer where the metal layer has extending portions into the visible area, increasing contact area and reducing surface resistance, and a manufacturing method that patterns both areas simultaneously to form a peripheral circuit and touch sensing electrode, eliminating the need for single metal layer alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the overlapping area between touch electrodes and peripheral circuits is increased to reduce overlapping impedance, then the overlapping stability is improved, but the peripheral area size increases

Engineering Contradiction:

Improveoverlapping stabilityVSAvoidperipheral area size

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent applies local quality by using metal nanowire material specifically in the overlapping region between touch electrodes and peripheral circuits. This localized application of high-conductivity material reduces overlapping impedance only where needed, without requiring an increase in the overall peripheral area. The metal nanowire layer is deposited selectively in the overlapping region to provide enhanced electrical conductivity precisely at the critical interface.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the material parameter of the overlapping region by introducing metal nanowire material with superior electrical conductivity compared to conventional transparent conductive materials. This parameter change (material composition) directly reduces the overlapping impedance, allowing for stable signal transmission without increasing the overlapping area or peripheral dimensions.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If metal nanomaterials are used as touch electrode material, then the touch sensitivity is improved, but the surface resistance increases due to material characteristics

Engineering Contradiction:

Improvetouch sensitivityVSAvoidsurface resistance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent employs composite materials by combining metal nanowires with transparent conductive oxide materials or conductive polymers. This composite structure leverages the high conductivity and touch sensitivity of metal nanowires while compensating for their high surface resistance through the complementary properties of the transparent conductive material. The composite layer achieves both low surface resistance and high touch sensitivity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional single metal layer alignment is used in peripheral area, then the manufacturing process is simplified, but alignment tolerance errors occur affecting overlapping stability

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidalignment tolerance

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts the alignment-critical function from the peripheral circuit metal layer by introducing a separate metal nanowire layer dedicated to the overlapping region. This separation allows the peripheral circuit metal layer to be positioned without strict alignment requirements, while the metal nanowire layer ensures reliable electrical contact in the overlapping area. The alignment-sensitive function is isolated to a layer that can be independently optimized.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces the metal nanowire layer as an intermediary between the peripheral circuit metal layer and the touch electrode. This intermediary layer acts as a buffer that compensates for alignment tolerances, allowing the peripheral circuit to be manufactured with relaxed alignment requirements while maintaining reliable electrical connection through the flexible and conductive metal nanowire medium.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11474649B2Touch sensor and manufacturing method thereof

Publication Date: 2022.10.18 TPK ADVANCED SOLUTIONS

AI summary

A touch sensor having a visible area and a peripheral area on at least one side of the visible area includes a substrate, a metal nanowire layer, and a metal layer. The metal nanowire layer is disposed on the substrate and has a first portion corresponding to the visible area and a second portion corresponding to the peripheral area. The metal layer is disposed on the second portion of the metal nanowire layer and has at least one extending portion extending into the visible area, in which the extending portion overlaps the first portion of the metal nanowire layer.