OLED Sloped Electrode Light Redirection

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Solution Overview

Problem

Current organic light-emitting display apparatuses face limitations in light efficiency due to the lack of effective structures for redirecting and enhancing light emission, particularly in the design of electrodes and pixel defining layers.

Innovation Solution

The proposed solution involves an organic light-emitting display apparatus with a substrate, an insulating layer featuring a recess with a sloped sidewall, a first electrode, an organic emission layer, and a second electrode, along with a pixel defining layer and a bump on the pixel defining layer, where the first electrode is disposed on the sloped sidewall to reflect light, and the bump is designed to redirect emitted light for improved efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional flat electrode structure is used, then the device structure is simple, but light emission efficiency is low due to lack of light redirection

Engineering Contradiction:
Improveelectrode structure simplicityVSAvoidlight emission efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The first electrode is designed with a sloped sidewall forming an inclined surface instead of a flat structure. This curved/angled geometry enables light reflected from the organic emission layer to be redirected toward the viewer, improving light emission efficiency while maintaining manufacturing feasibility through standard deposition techniques

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The electrode structure transitions from a two-dimensional flat surface to a three-dimensional inclined structure with a sloped sidewall. This dimensional change creates additional light reflection paths and redirects light in multiple directions, enhancing overall light output without significantly complicating the manufacturing process

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the first electrode reflects light, then light emission efficiency improves, but the pixel defining layer must be precisely positioned to avoid blocking reflected light

Engineering Contradiction:
Improvelight emission efficiencyVSAvoidpixel defining layer positioning
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The pixel defining layer is designed to extend over the first electrode in advance, creating a predetermined spatial relationship between the two components. This preliminary positioning arrangement ensures that the pixel defining layer does not block reflected light paths while maintaining precise alignment during the manufacturing process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pixel defining layer exhibits different spatial configurations at different locations: it extends over the first electrode in certain regions to prevent light blocking, while defining emissive and non-emissive boundaries in other regions. This localized variation in structure optimizes both light reflection and manufacturing precision

Inventive Principle:
Principle #3Local quality

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 configuration enhances light emission efficiency by reflecting and redirecting light emitted by the organic emission layer, resulting in improved light output and display performance.

Implementation Method 1

the first electrode is arranged to reflect light which is emitted by the organic emission layer

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

holes injected from the hole injecting electrode and electrons injected from the electron injecting electrode are combined in the organic emission layer to generate excitons, and the excitons fall from an excited state to a ground state and generate light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2811522B1Organic light-emitting display apparatus
Publication Date: 2020.05.06 SAMSUNG DISPLAY CO LTD
  • EP2811522B1 patent drawingFigure 1~2
  • EP2811522B1 patent drawingFigure 3~4A
  • EP2811522B1 patent drawingFigure 4B~4C

AI summary

An organic light-emitting display apparatus includes an insulating layer (210) including a inclined structure (209); a first electrode (221) on the insulating layer; a pixel defining layer (223) on the insulating layer and the first electrode, and defining an emissive region and a non-emissive region; a bump (225) on the pixel defining layer; an organic emission layer (220) on the first electrode; and a second electrode (222) on the organic emission layer.