OLED Display Panel Layout for Alignment-Tolerant Top Emission

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Solution Overview

Problem

Conventional organic light emitting diode (OLED) display panels face defects due to alignment errors and adhesion issues between the array and counter substrates, particularly in top emission-type panels, leading to problems like fall-off of auxiliary cathodes and spacer layers.

Innovation Solution

The OLED display panel design includes a counter substrate with organic light emitting diodes, a spacer layer, and a first electrode layer on the array substrate to maintain spacing and electrical connection, eliminating the need for a pixel definition layer in the array substrate and enhancing adhesion through a reflective electrode layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a pixel definition layer is used in the array substrate to define subpixels, then subpixel definition is achieved, but alignment errors cause adhesion issues and fall-off of auxiliary cathodes and spacer layers

Engineering Contradiction:
Improvealignment precision between array and counter substratesVSAvoidadhesion stability of auxiliary cathodes and spacer layers
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent removes the pixel definition layer from the array substrate entirely. Instead, subpixels are defined by the counter substrate's color filter layer and the organic light emitting diode structure itself. This extraction eliminates the adhesion problems between the array substrate's auxiliary cathode and the pixel definition layer, as well as alignment issues between the array and counter substrates.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional OLED structure by placing the organic light emitting diodes on the counter substrate rather than the array substrate. This inversion allows the counter substrate to define the subpixel boundaries through its color filter and electrode structure, eliminating the need for a pixel definition layer in the array substrate and resolving the associated adhesion and alignment problems.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of manufacture

If top emission-type OLED structure is used, then emission direction is controlled, but adhesion issues and fall-off of auxiliary cathodes occur

Engineering Contradiction:
Improveemission direction controlVSAvoidadhesion stability of auxiliary cathodes
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent removes the auxiliary cathode structure from the array substrate that causes adhesion problems in top emission-type OLEDs. The emission direction is controlled through the counter substrate's electrode and color filter structure instead, eliminating the fall-off issues while maintaining top emission functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If alignment tolerance is increased to reduce fabrication defects, then manufacturing yield improves, but adhesion between substrates deteriorates

Engineering Contradiction:
Improvefabrication yieldVSAvoidadhesion between array and counter substrates
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent eliminates the pixel definition layer and auxiliary cathode structures that create adhesion interfaces prone to failure. By defining subpixels through the counter substrate's color filter and electrode structure, the design removes the adhesion-critical interfaces, allowing larger alignment tolerances without compromising bond strength, thereby improving fabrication yield.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3794644B1Organic light emitting diode display panel and fabricating method thereof
Publication Date: 2025.08.06 BOE TECHNOLOGY GROUP CO LTD
  • EP3794644B1 patent drawingFigure 1
  • EP3794644B1 patent drawingFigure 2
  • EP3794644B1 patent drawingFigure 3A~3C

AI summary

The present application provides an organic light emitting diode display panel having a plurality of subpixels. The organic light emitting diode display panel includes an array substrate; and a counter substrate facing the array substrate. The counter substrate includes a plurality of organic light emitting diodes. The array substrate includes a first base substrate; a plurality of thin film transistors on the first base substrate for driving light emission of the plurality of organic light emitting diodes in the counter substrate; and a first electrode layer. The first electrode layer electrically connects the plurality of organic light emitting diodes to the plurality of thin film transistors, respectively.