Organic Light Emitting Device Solution Process Manufacturing

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Solution Overview

Problem

The existing manufacturing processes for organic light emitting devices require costly vacuum deposition for all layers, limiting productivity, especially for large-size devices, as the solution process for forming the electron transporting layer is not yet developed due to solvent damage issues.

Innovation Solution

The method involves forming a hole injecting layer, hole transporting layer, and emission layer through a solution process, while using a vacuum deposition process for the electron injecting layer, which includes diffusing n-type dopants to create a second emission layer with enhanced electron transporting characteristics, reducing the need for a separate electron transporting layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vacuum deposition process is used for forming all organic layers, then device performance is maintained, but manufacturing cost increases and productivity decreases

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidmanufacturing cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent segments the organic layers into two groups: HIL, HTL, and EML are formed by solution process, while ETL and EIL are formed by vacuum deposition. This segmentation allows different manufacturing approaches to be applied to different layers based on their specific requirements, improving overall productivity while maintaining device performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the manufacturing parameter (process type) for different layers. By using solution process for certain layers and vacuum deposition for others, the patent optimizes the balance between productivity and device performance, reducing the extent of vacuum deposition required while maintaining necessary device characteristics.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If solution process is used for forming electron transporting layer, then productivity is enhanced, but EML surface is damaged by solvent

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidsolvent damage to EML

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an electron transporting layer as an intermediary between the EML and EIL. This ETL layer protects the EML from direct contact with the EIL formation process, preventing solvent damage while enabling the use of solution process for ETL formation, thus enhancing productivity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the electron transporting function into a separate ETL layer formed by solution process, distinct from the EML formed by vacuum deposition. This separation allows the EML to be protected from solvent exposure while the ETL can be formed using the more productive solution process.

Inventive Principle:

Principle #2Taking out (Extraction)

3Area of stationary object

If vacuum deposition equipment size increases for large-size devices, then device size is achieved, but productivity is lowered in mass production

Engineering Contradiction:

Improvedevice sizeVSAvoidmass production efficiency

Core Design Contradiction:

Area of stationary objectVSProductivity

Solution Approach 1:

The patent replaces the mechanical vacuum deposition system with a solution process for forming certain organic layers. This substitution eliminates the need for large-scale vacuum deposition equipment, enabling mass production of large-size devices without the productivity losses associated with scaling up vacuum systems.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances productivity by minimizing vacuum deposition and improving electron transporting characteristics, allowing for efficient light emission and reducing manufacturing costs for large-size organic light emitting devices.

Implementation Method 1

the second emission layer includes a same material as a material of the first emission layer and further includes an n-type dopant material

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

Organic layers, such as the HIL, the HTL, the EML, the ETL, and the EIL which are disposed between the anode and the cathode, are formed through a vacuum deposition process in a vacuum chamber

Methodology Applied

Scientific EffectVacuum deposition: Physical Vapour Deposition

Implementation Method 3

When the electron generated from the cathode and the hole generated from the anode are injected into the emission layer, the injected electron and hole are combined to generate an exciton, and the exciton is shifted from an excited state to a ground state to emit light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS9590200B2Organic light emitting device, method of manufacturing the same, and organic light emitting display apparatus using the same

Publication Date: 2017.03.07 LG DISPLAY CO LTD

AI summary

Disclosed are an organic light emitting device, a method of manufacturing the same, and an organic light emitting display apparatus using the same. In the organic light emitting device, an electron transporting layer is not provided between an emission layer and an electron injecting layer. Instead, the emission layer includes a first emission layer on a hole transporting layer, and a second emission layer on the first emission layer. The second emission layer includes a same material as a material of the first emission layer and further includes an n-type dopant material.