Transparent OLED Manufacturing via Substrate Segmentation

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Solution Overview

Problem

The manufacturing of transparent OLED displays faces challenges in achieving high yield rates and production efficiency due to the potential damage of the organic light-emitting layer during the sputtering process for creating transparent electrodes, which also results in low conductivity and transparency.

Innovation Solution

A method involving the formation of transparent OLED displays by preparing the cathode and anode on separate substrates, using transparent conductive metal oxides, and employing a chemical reaction between organic materials with positive and negative radicals to securely attach the substrates, thereby avoiding damage to the light-emitting layer and enhancing conductivity and transparency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sputtering process is used to manufacture transparent electrodes, then transparency and conductivity can be achieved, but the organic light-emitting layer may be damaged when too-high power is applied

Engineering Contradiction:
Improveintegrity of light-emitting layerVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the manufacturing process into two independent stages: first manufacturing the lower substrate with cathode and transport layers, then separately manufacturing the upper substrate with anode and hole inject layer, finally bonding them together. This segmentation allows the anode to be manufactured without risking damage to the light-emitting layer, as the light-emitting layer is already protected in the lower substrate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary actions by pre-manufacturing the lower substrate with the light-emitting layer and transport layers before introducing the anode. The hole transport layer is prepared with positive radicals in advance, which will later react with negative radicals on the hole inject layer during bonding, ensuring proper attachment without direct contact between anode and light-emitting layer.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If sputtering process is used to manufacture transparent electrodes, then conductivity can be achieved, but film forming time is too long and yield rate is low when too-low power is applied

Engineering Contradiction:
Improveyield rateVSAvoidconductivity and transparency quality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By segmenting the manufacturing process into separate substrate preparations followed by bonding, the patent eliminates the need for prolonged low-power sputtering. The transparent electrodes can be manufactured more efficiently in separate steps without compromising conductivity or transparency, thereby improving yield rate and productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces organic radical layers (positive radicals on hole transport layer, negative radicals on hole inject layer) as intermediaries that facilitate bonding between substrates. This intermediary mechanism replaces the need for extended sputtering processes, enabling faster manufacturing while maintaining electrode quality through the chemical reaction between radicals during bonding.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If separate substrate preparation and bonding method is used, then damage to light-emitting layer is avoided and manufacturing efficiency is improved, but additional bonding process is required

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidnumber of manufacturing steps
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent uses organic radicals as intermediaries that enable self-alignment and secure bonding between substrates. The positive radicals on the hole transport layer and negative radicals on the hole inject layer attract each other through electrostatic interaction, creating strong bonds that automatically align the substrates, thereby simplifying the bonding process despite the additional step.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of the transport layers by introducing radical groups (positive radicals on hole transport layer, negative radicals on hole inject layer). This parameter change enables chemical bonding between substrates, which is more reliable and efficient than physical bonding methods, offsetting the complexity of the additional bonding step through improved bond strength and alignment.

Inventive Principle:
Principle #35Parameter changes

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 approach improves yield rates and manufacturing efficiency by preventing damage to the light-emitting layer during electrode formation, achieving high conductivity and transparency, and simplifying the manufacturing process while providing a durable and efficient OLED display.

Implementation Method 1

the positive radicals on the surface of the HTL and the negative radicals on the surface of the HIL being mutually attracted by Coulomb force to create a chemical reaction

Methodology Applied
Scientific EffectCoulomb force: Coulomb's Law

Data Source

PatentEP3528299B1Manufacturing method of a transparent OLED display
Publication Date: 2022.11.09 WUHAN CHINA STAR OPTOELECTRONICS TECH CO LTD
  • EP3528299B1 patent drawingFigure 1~2
  • EP3528299B1 patent drawingFigure 3~4

AI summary

Provided are a transparent OLED display and a manufacturing method for same. Arranging a negative electrode (12) and a positive electrode (22) on two different substrates effectively avoids damage to emissive layers made of organic light-emitting materials when sputtering OLED top positive electrodes, and improves product yield; utilizing transparent, electrically-conductive metal oxides to manufacture OLED negative electrodes and positive electrodes effectively resolves the problem of requiring high-conductivity and high-transparency electrode materials when manufacturing transparent OLED displays. In addition, during the manufacturing process, the upper and lower substrates can be produced at the same time and then batch-assembled by means of pressing together, thus greatly increasing production efficiency. The present OLED display is easy to manufacture and shows good product performance.