Planarization Insulating Layer Protrusion for OLED Mask Protection

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Solution Overview

Problem

The existing manufacturing processes for organic light-emitting display devices often damage the pixel definition layer due to the use of masks, and these processes are costly due to the need for additional expensive mask structures.

Innovation Solution

A display device design that incorporates a planarization insulating layer with a protruding portion extending through the pixel definition layer, allowing the mask to be suspended above the pixel definition layer, reducing direct contact and damage, and using a halftone mask to form the protruding portion without the need for additional expensive masks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a mask is used in the manufacturing process to define pixel openings, then the pixel definition layer can be formed, but the mask causes damage to the pixel definition layer

Engineering Contradiction:
Improvepixel opening definitionVSAvoiddamage to pixel definition layer
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a protruding portion that extends in the vertical dimension (thickness direction) from the substrate. This protruding portion rises above the pixel definition layer, creating a three-dimensional structure that allows the mask to be positioned higher and avoid direct contact with the pixel definition layer, thus preventing damage while maintaining manufacturing precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The protruding portion acts as an intermediary structure between the mask and the pixel definition layer. By providing this intermediate element, the mask can be supported and positioned without directly contacting the fragile pixel definition layer, thereby mediating the harmful interaction while preserving the necessary patterning function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If additional mask structures are used to protect the pixel definition layer, then damage can be prevented, but the fabrication cost increases

Engineering Contradiction:
Improvedamage prevention to pixel definition layerVSAvoidmask structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the protective function with the existing planarization insulating layer by forming a protruding portion from it. Instead of adding a separate protective mask structure, the same insulating layer material is shaped to provide both planarization and protection, eliminating the need for additional expensive mask structures while preventing damage to the pixel definition layer.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The protruding portion of the planarization insulating layer serves multiple functions: it provides planarization for the underlying transistor structure, acts as a support for mask positioning, and protects the pixel definition layer from damage. This multi-functionality eliminates the need for separate protective structures, reducing device complexity and fabrication cost.

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

3Object-affected harmful factors

If the planarization insulating layer is made thicker to provide better protection, then damage prevention improves, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveprotection of pixel definition layerVSAvoidfabrication process simplicity
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies local quality by making the planarization insulating layer thicker only in specific regions where protection is needed (forming the protruding portion), rather than uniformly increasing the thickness everywhere. This localized thickening provides targeted protection to the pixel definition layer while maintaining ease of manufacture in other regions, avoiding unnecessary complexity in the overall fabrication process.

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

This design effectively prevents damage to the pixel definition layer and reduces fabrication costs by eliminating the requirement for additional expensive mask structures, enhancing the manufacturing efficiency and cost-effectiveness.

Implementation Method 1

using a halftone mask to form the protruding portion

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3767682B1Display device and method of fabricating the same
Publication Date: 2023.05.03 SAMSUNG DISPLAY CO LTD
  • EP3767682B1 patent drawingFigure 1~2
  • EP3767682B1 patent drawingFigure 3~4
  • EP3767682B1 patent drawingFigure 5

AI summary

A display device includes a substrate (SUB), a transistor (TR) disposed on the substrate (SUB), a planarization insulating layer (P_IS) disposed on the transistor (TR) and the substrate (SUB), a pixel definition layer (PDL) disposed on the planarization insulating layer (P_IS), the pixel definition layer (PDL) comprising a pixel opening (PX_OP), an emission element (OLED) in the pixel opening (PX_OP) and connected to the transistor (TR), wherein, the planarization insulating layer (P_IS) defines a protruding portion (PRT) which extends through the pixel definition layer (PDL) to extend further from the substrate (SUB) than the pixel definition layer (PDL).