OLED Face Electrode Bending to Reduce IR Drop

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Solution Overview

Problem

Organic light emitting display devices face challenges in preventing damage to the interlayer with an emitting layer and reducing current resistance (IR) drop in face electrodes, particularly due to issues with the formation of face electrodes using transparent or polymer materials.

Innovation Solution

The solution involves manufacturing an organic light emitting display device with a lower substrate having a pixel electrode and an interlayer with an emitting layer, and an upper substrate featuring a face electrode and sealing member that conform to the lower substrate's surface without gaps, using high pressure and heat to bend the sealing member and conductive layer to prevent damage and reduce IR drop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If face electrodes are formed as thin films by deposition of Ag to maintain light transmission, then light transmission is improved, but IR drop in face electrodes increases

Engineering Contradiction:

Improvelight transmissionVSAvoidIR drop

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The face electrode is constructed as a composite structure combining a transparent conductive oxide layer (such as ITO or IZO) with a reflective metal layer (such as Ag, Al, or Mo). This composite structure simultaneously provides high light transmission through the transparent oxide layer and low electrical resistance through the conductive metal layer, resolving the contradiction between light transmission and IR drop.

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If transparent electrodes such as ITO are used for face electrodes to improve light transmission, then light transmission is improved, but the interlayer is damaged by sputtering during formation

Engineering Contradiction:

Improvelight transmissionVSAvoiddamage to interlayer

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The face electrode formation process is segmented into two separate steps: first forming the transparent conductive oxide layer by sputtering, then forming the reflective metal layer by vacuum deposition. By segmenting the process and using different deposition methods for different layers, the interlayer is protected from damage while still achieving the desired light transmission properties.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The conventional sequence is inverted: instead of forming the transparent electrode first and then depositing metal, the transparent conductive oxide layer is formed first by sputtering, and then the reflective metal layer is deposited on top. This inversion allows the use of gentle vacuum deposition for the metal layer, avoiding sputtering damage to the interlayer while maintaining light transmission.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If polymer electrodes are used for face electrodes to improve flexibility, then ease of manufacture is improved, but the interlayer is damaged by moisture during wet process formation

Engineering Contradiction:

Improveformation processVSAvoiddamage to interlayer

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

A protective barrier layer (such as a planarization layer or encapsulation layer) is introduced as an intermediary between the interlayer and the polymer face electrode. This barrier layer prevents moisture from the wet polymer formation process from penetrating to and damaging the interlayer, while still allowing the polymer electrode to be formed using wet processes.

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

This approach effectively reduces damage to the emitting layer and minimizes current resistance drop in the face electrodes, enhancing the performance and reliability of the organic light emitting display device.

Implementation Method 1

using high pressure and heat to bend the sealing member and conductive layer

Methodology Applied

Scientific EffectHeat: Heating

Implementation Method 2

bend the sealing member and conductive layer to conform to the lower substrate's surface without gaps

Methodology Applied

Scientific EffectMechanical deformation: Deformation

Data Source

PatentUS8393930B2Organic light emitting display device and method of manufacturing the same to prevent damage to an interlayer

Publication Date: 2013.03.12 SAMSUNG DISPLAY CO LTD

AI summary

An organic light emitting display device prevents damage to an interlayer including an emitting layer and reduces IR drop in face electrodes, and a method of manufacturing the same. The organic light emitting display device includes: a substrate; a pixel electrode disposed on the substrate; an interlayer comprising an emitting layer disposed on the pixel electrode; a face electrode on the interlayer; and a sealing member disposed on the face electrodes, wherein the sealing member and the face electrode are bent along a curve of an upper portion of a layer below the face electrode so as to prevent a gap between the sealing member and the face electrode, and between the face electrode and the layer below the face electrode.