Test Cover Layer Protects Touch Display Patterns

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Solution Overview

Problem

During the manufacturing process of touch display devices, test patterns formed on the substrate are often damaged due to the low adhesive force between these patterns and the underlying thin-film layers, leading to defects and process inefficiencies.

Innovation Solution

A test cover layer is introduced, formed from the same material as the insulating films between the light-emitting element and the touch electrode, which covers the test patterns to protect them from damage during the manufacturing of touch conductive layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If test patterns are formed on the substrate prior to touch electrode formation, then test patterns can be used for quality inspection, but the test patterns may be damaged due to low adhesive force between the patterns and underlying thin-film layers

Engineering Contradiction:
Improvetest pattern integrityVSAvoidadhesive force of test patterns
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

A buffer layer is introduced as an intermediary between the test pattern and the underlying thin-film layers. This buffer layer has higher adhesive force to both the test pattern and the underlying layers, serving as a mediator that prevents direct damage transmission during the touch electrode formation process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer layer is formed beforehand on the substrate before the test pattern is created. This pre-positioned cushioning layer provides protective support during subsequent manufacturing steps, preventing the test pattern from being torn out when touch electrodes are formed in overlapping regions.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Adaptability or versatility

If touch electrodes are formed in regions overlapping with test patterns, then touch screen functionality is achieved, but the test patterns are damaged due to mechanical stress during manufacturing

Engineering Contradiction:
Improvetouch screen functionalityVSAvoidtest pattern integrity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The buffer layer acts as a mediator that allows the touch electrode to be formed in the overlapping region while protecting the test pattern from mechanical damage during the electrode formation process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The buffer layer is prepared in advance in the regions where test patterns will be formed, creating a protective foundation before the test patterns and touch electrodes are manufactured, thereby preventing damage during subsequent processing steps.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If no protective layer is added for test patterns, then device complexity is reduced, but test patterns are vulnerable to damage during manufacturing

Engineering Contradiction:
Improvelayer structure simplicityVSAvoidtest pattern durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The buffer layer serves multiple functions: it provides adhesive support for the test pattern, acts as a protective cushion during manufacturing, and maintains structural integrity during touch electrode formation. This multi-functionality justifies the additional layer despite the increase in complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3843148B1Touch display device
Publication Date: 2024.07.17 LG DISPLAY CO LTD
  • EP3843148B1 patent drawingFigure 1
  • EP3843148B1 patent drawingFigure 2
  • EP3843148B1 patent drawingFigure 3

AI summary

A touch display device for preventing damage to test patterns (190) is disclosed. The touch display device is configured such that a test cover layer (192), which is formed of the same material as at least one of a plurality of insulating films disposed between a light-emitting element and a touch electrode, is disposed on a test pattern formed on a peripheral portion of a substrate, thereby preventing damage to the test pattern during the process of manufacturing a touch sensor.