Touch Display Shielding Pattern for Routing Trace Isolation

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Solution Overview

Problem

Capacitive touch panels in handheld electronic devices face issues with capacitance coupling and electromagnetic interference, which affect sensing accuracy and increase production costs due to the need for shielding and potential exposure of wirings.

Innovation Solution

A touch display module with a shielding pattern that covers routing traces to prevent capacitance coupling and includes a grounding mechanism to mitigate electromagnetic interference, using a shielding pattern on the first surface with a vertical projection covering the routing traces and allowing for smaller line widths and intervals to reduce the device's frame size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shielding area is formed on the transparent cover to cover the wirings, then the wirings are protected from exposure and capacitance coupling, but the production costs increase

Engineering Contradiction:
Improvesensing accuracyVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the shielding function with the existing transparent cover structure by forming a conductive shielding layer directly on the cover surface. This integration eliminates the need for separate shielding components, thereby protecting the wirings from capacitance coupling and electromagnetic interference while avoiding additional production costs associated with separate shielding parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a conductive shielding layer as an intermediary between the exposed wirings and the external environment (user's finger or electromagnetic fields). This shielding layer acts as a mediator that blocks capacitance coupling effects and electromagnetic interference from reaching the sensing electrodes, thereby improving sensing accuracy without requiring structural changes to the touch panel itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the wirings are left exposed without shielding, then production costs are reduced, but capacitance coupling occurs between the finger and wirings affecting sensing accuracy

Engineering Contradiction:
Improveproduction costVSAvoidsensing accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The conductive shielding layer serves as an intermediary that prevents direct interaction between the user's finger and the exposed wirings. By placing this shielding layer on the transparent cover, the patent blocks the capacitance coupling pathway while maintaining the cost-effective approach of leaving wirings visually exposed, thus preserving sensing accuracy without increasing production costs.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If larger line widths and intervals are used for routing traces, then manufacturing is easier, but the frame size of the device increases

Engineering Contradiction:
Improvemanufacturing easeVSAvoidframe size
Core Design Contradiction:
Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent applies different design approaches to different regions of the touch panel. In the sensing area, precise routing traces with smaller line widths and intervals are used to minimize frame size. In the non-sensing peripheral area, the shielding layer provides protection while allowing for manufacturing tolerances. This localized differentiation enables smaller overall device dimensions while maintaining manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

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 solution effectively insulates routing traces from capacitance effects, prevents electrostatic discharge and electromagnetic interference, and reduces the frame size of handheld electronic devices by using a shielding pattern that can be grounded, enhancing the reliability and appearance of touch display modules.

Implementation Method 1

a shielding pattern 128 is disposed on the first surface 121a, and a vertical projection of the shielding pattern 128 on the second surface 121b covers the routing traces 126

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

the shielding pattern 128 insulates and protects the routing traces 126 and prevents the normal operation of the handheld electronic apparatus from a capacitance coupling effect that is generated when an object contacts the routing traces 126

Methodology Applied
Scientific EffectCapacitance coupling: Capacitance

Data Source

PatentEP2713249B1Touch display module and handheld electronic apparatus
Publication Date: 2017.08.09 HTC CORP
  • EP2713249B1 patent drawingFigure 1A
  • EP2713249B1 patent drawingFigure 1B
  • EP2713249B1 patent drawingFigure 2

AI summary

A touch display module includes a display panel and a touch panel. The touch panel has a sensing section and a bonding section. The touch panel includes a first substrate, driving lines, sensing lines, routing traces, and a shielding pattern. The driving lines are arranged in parallel on a first surface of the first substrate. The sensing lines are arranged in parallel on a second surface of the first substrate and form a sensing array with the driving lines. The routing traces are disposed on the second surface outside the sensing section. The routing traces are electrically connected with the sensing lines and extend to the bonding section. The shielding pattern is disposed on the first surface, and a vertical projection of the shielding pattern on the second surface covers the routing traces. A handheld electronic apparatus with the touch display module is also provided.