OLED Planarization Film for Electrode Height Compensation

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Solution Overview

Problem

In organic light emitting display (OLED) devices, particularly in head-mounted displays, the structural disconnection between anode electrodes and cathode electrodes or charge generation layers due to height differences leads to inefficient hole and electron transportation, affecting light emission and increasing resistance.

Innovation Solution

A planarization film is introduced between the electrodes and the organic light emitting layer to create a uniform surface, minimizing height differences and preventing structural disconnection, thereby enhancing the transportation of holes and electrons and improving light emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high potential voltage is applied to the anode electrode and a low potential voltage is applied to the cathode electrode, then holes and electrons are moved to the organic light emitting layer and combined to emit light, but structural disconnection between electrodes due to height differences leads to inefficient charge transportation and increased resistance

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidresistance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A planarization film is introduced as an intermediary layer between the electrode and the organic light emitting layer. This film fills height differences and structural discontinuities, creating a uniform surface that enables efficient charge transportation while reducing resistance and preventing structural disconnection between electrodes

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The planarization film is selectively formed in regions with height differences between the anode electrode and the organic light emitting layer. By locally addressing the structural discontinuities rather than uniformly modifying the entire structure, the film optimizes charge transportation pathways where needed most while maintaining overall device architecture

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the organic light emitting layer is deposited on electrodes with height differences, then the layer cannot be uniformly deposited, but adding a planarization film increases device complexity

Engineering Contradiction:
Improveuniformity of organic light emitting layer depositionVSAvoidnumber of layers
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The planarization film is formed in advance before depositing the organic light emitting layer. This preliminary action creates a uniform surface foundation that ensures even deposition of the organic layer, preventing thickness variations and structural disconnections that would occur without the planarization step

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The planarization film serves as an intermediary layer that decouples the electrode structure from the organic light emitting layer deposition process. This intermediate structure allows the organic layer to be deposited uniformly without being directly affected by the underlying electrode height differences, simplifying the overall manufacturing process despite adding one layer

Inventive Principle:
Principle #24Intermediary (Mediator)

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 planarization film ensures uniform deposition of the organic light emitting layer, reducing leakage currents and increasing the resistance of the OLED, thus enhancing the display's performance and minimizing the influence on adjacent pixels.

Implementation Method 1

the organic light emitting layer, a second electrode, and an encapsulation film are sequentially deposited on the planarization film

Methodology Applied
Scientific EffectPhysical Vapour Deposition: Physical Vapour Deposition

Implementation Method 2

holes and electrons are respectively moved to the organic light emitting layer via the hole transporting layer and the electron transporting layer, and are then combined to one another in the organic light emitting layer, to thereby emit light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3316310B1Organic light emitting display device, head mounted display including the same, and method for manufacturing the same
Publication Date: 2024.06.26 LG DISPLAY CO LTD
  • EP3316310B1 patent drawingFigure 1
  • EP3316310B1 patent drawingFigure 2
  • EP3316310B1 patent drawingFigure 3A~3B

AI summary

Disclosed is an organic light emitting display device which is capable of preventing an anode electrode from being structurally disconnected with a cathode electrode or a charge generation layer of an organic light emitting layer, and a head mounted display including the same, and a method for manufacturing the same, wherein the organic light emitting display device may include an insulating film, a first electrode and another first electrode on the insulating film, a planarization film filling a space between the first electrode and the another first electrode, an organic light emitting layer on the first electrode and the another first electrode and the planarization film, and a second electrode on the organic light emitting layer.