Circular Display Insertion Member for Substrate Crack Prevention

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Solution Overview

Problem

Display apparatuses with circular display portions face reliability issues due to micro-cracks caused by external forces during the bonding process of the cover window, and the existing resin coating methods struggle to fill gaps effectively, leading to contamination and decreased productivity.

Innovation Solution

A display apparatus with a circular display portion featuring an insertion member made of elastomer material, which is inserted into the gap space between the substrate and the cover window to seal the gap and reduce the risk of micro-cracks, improving adhesiveness and reducing the bezel width by forming a concentric circular shape with the substrate and cover window.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a gap space is maintained between the substrate and cover window during bonding, then the bonding process can be completed, but micro-cracks occur on the substrate due to external forces

Engineering Contradiction:
Improvesubstrate integrityVSAvoidmicro-cracks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A resin coating layer is applied to the substrate surface in the gap space region before the bonding process. This resin layer acts as a cushioning material that absorbs and distributes external bonding forces, preventing direct stress concentration on the substrate that would cause micro-cracks. The resin coating is applied beforehand to ensure proper positioning and force distribution during subsequent bonding operations.

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

2Strength

If resin coating layer thickness is increased to fill the gap space, then adhesiveness between flexible printed circuit board and pad is improved, but processing time for curing increases

Engineering Contradiction:
ImproveadhesivenessVSAvoidcuring time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The resin coating layer thickness is optimized to a specific range (1-10 μm) that provides sufficient adhesiveness between the flexible printed circuit board and pad while maintaining a thickness that can be cured within reasonable processing time. This parameter optimization balances the competing requirements of bond strength and manufacturing efficiency.

Inventive Principle:
Principle #35Parameter changes

3Strength

If resin coating layer is used to seal the gap space, then adhesiveness is improved, but the resin may spread during attachment process and contaminate peripheral area

Engineering Contradiction:
ImproveadhesivenessVSAvoidcontamination
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The resin coating layer is applied with localized quality control, concentrating the adhesive material precisely in the gap space region where it is needed for bonding. The coating density and distribution are optimized to provide sufficient adhesion locally while preventing excessive resin migration to peripheral areas during the attachment process, thereby avoiding contamination.

Inventive Principle:
Principle #3Local quality

4Device complexity

If direct bonding process is used to attach cover window, then manufacturing complexity is reduced, but micro-cracks occur due to bonding force applied to substrate

Engineering Contradiction:
Improvebonding process complexityVSAvoidsubstrate integrity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The resin coating layer serves as a pre-applied cushioning material that enables direct bonding to proceed without causing substrate damage. By distributing the bonding forces through the compliant resin layer, the process maintains simplicity while preventing micro-crack formation, thus resolving the contradiction between process simplicity and substrate integrity.

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

The solution enhances the reliability of the display apparatus by preventing micro-cracks and improving the bonding process, while also reducing the bezel width and increasing productivity by effectively sealing the gap space and absorbing external forces.

Implementation Method 1

an insertion member in a gap space between an edge of the substrate and an edge of the cover window, and interposed between the driving circuit connecting portion and the cover window

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3012683B1Display apparatus
Publication Date: 2022.05.04 LG DISPLAY CO LTD
  • EP3012683B1 patent drawingFigure 1~2
  • EP3012683B1 patent drawingFigure 3
  • EP3012683B1 patent drawingFigure 4

AI summary

Disclosed is a display apparatus having a circular display portion, wherein the display apparatus includes a cover window (170) for covering a circular display portion on a substrate (110), and an insertion member (190) provided in a gap space between an edge of the substrate (110) and an edge of the cover window (170), thereby improving reliability of the substrate.