Insulated Metal Wire Frame Traces for Narrow Bezel Touch Sensors

Solution Overview

Problem

Existing touch screen technologies face challenges in reducing the width of frame traces while maintaining electrical integrity, as narrow frames require closer spacing of metal wires, leading to increased costs and yield decreases due to potential short circuits.

Innovation Solution

A touch sensor design featuring metal wires with an insulation layer wrapped around their periphery, allowing for closer spacing or stacking without electrical contact, using conductive silver paste and specific solvents like propylene glycol monomethyl ether or benzene solvents, to form frame traces that prevent short circuits and reduce frame width.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the frame width is reduced to achieve narrow bezel technology, then the product texture and screen-to-body ratio are improved, but the manufacturing cost increases and yield decreases due to the complexity of frame trace fabrication

Engineering Contradiction:

Improveframe widthVSAvoidmanufacturing cost and yield

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The frame trace is segmented into multiple parallel metal wire lines instead of a single continuous trace. This segmentation allows each wire to be independently insulated and positioned, enabling closer spacing while maintaining electrical integrity. The insulation layer is applied to each metal wire individually, creating discrete segments that can be precisely controlled during manufacturing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An insulation layer is introduced as an intermediary substance between adjacent metal wires. This insulation layer prevents direct electrical contact between wires while allowing them to be positioned very close together. The insulation acts as a mediator that enables the wires to maintain both electrical isolation and mechanical proximity, solving the short circuit risk associated with narrow frame traces.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If metal wires are spaced closer together to reduce frame width, then the frame trace area is reduced, but the risk of short circuits between adjacent wires increases

Engineering Contradiction:

Improveframe trace areaVSAvoidrisk of short circuits

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

An insulation layer is introduced as an intermediary substance between adjacent metal wires. This insulation layer prevents direct electrical contact between wires while allowing them to be positioned very close together. The insulation acts as a mediator that enables the wires to maintain both electrical isolation and mechanical proximity, solving the short circuit risk associated with narrow frame traces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin film insulation layer is applied to the outer periphery of each metal wire. This flexible thin film provides continuous electrical isolation along the length of each wire while occupying minimal space. The thin film structure allows for close wire spacing without compromising the reliability of electrical isolation, directly addressing the short circuit risk in narrow frame designs.

Inventive Principle:

Principle #30Flexible shells and thin films

3Area of stationary object

If the width and spacing between metal wires are reduced to narrow the frame, then the frame trace area is minimized, but the manufacturing precision requirements increase significantly

Engineering Contradiction:

Improveframe trace areaVSAvoidwire spacing precision

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

The frame trace is segmented into multiple parallel metal wire lines instead of a single continuous trace. This segmentation allows each wire to be independently insulated and positioned, enabling closer spacing while maintaining electrical integrity. The insulation layer is applied to each metal wire individually, creating discrete segments that can be precisely controlled during manufacturing.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A thin film insulation layer is applied to the outer periphery of each metal wire. This flexible thin film provides continuous electrical isolation along the length of each wire while occupying minimal space. The thin film structure allows for close wire spacing without compromising the reliability of electrical isolation, directly addressing the short circuit risk in narrow frame designs.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS12093476B2Touch sensor and method for making the same

Publication Date: 2024.09.17 NUOVO FILM SUZHOU CHINA INC

AI summary

The present invention provides a touch sensor and a method for making the same. The touch sensor includes a substrate, an electrode layer located in a window area, and a frame trace located in a frame trace area. The frame trace includes a plurality of metal wires. Each metal wire includes a metal wire body electrically connected to a corresponding electrode in the electrode layer and an insulation layer wrapped around an outer periphery of the metal wire body. In this way, the width of the frame trace area can be further reduced.