OLED Subpixel Aperture Ratio via Segmented Light Emission

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Solution Overview

Problem

In organic light-emitting display devices, the limited aperture ratio due to the wider region occupied by the transistor unit compared to the organic light-emitting diode hinders the implementation of high-resolution displays, especially when compensating circuits are added, as it restricts the emission area and efficiency.

Innovation Solution

The design incorporates a sub-pixel structure where the opening region and non-opening region are combined to form a light-emitting region, allowing the organic light-emitting diode to extend and emit light without being covered by electrodes or wiring, thereby increasing the aperture ratio and enabling higher resolution displays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the transistor unit occupies a wider region to accommodate switching and driving functions, then the device functionality is ensured, but the aperture ratio is reduced and light-emitting area is limited

Engineering Contradiction:
Improvedevice functionalityVSAvoidaperture ratio
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The sub-pixel is divided into two functional regions: an opening region for light emission and a non-opening region for transistor placement. This segmentation allows each region to be optimized for its specific function, resolving the conflict between device functionality and aperture ratio.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention merges the opening region and non-opening region into a single sub-pixel structure, where both regions work together to achieve high-resolution display. The light-emitting diode extends across both regions, utilizing the entire sub-pixel area effectively.

Inventive Principle:
Principle #5Merging (Combining)

2Area of stationary object

If the opening region is extended to increase aperture ratio, then light-emitting efficiency is improved, but the transistor unit placement becomes constrained

Engineering Contradiction:
Improvelight-emitting areaVSAvoidtransistor unit placement
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Different regions of the sub-pixel are assigned different properties: the opening region is optimized for light emission with transparent electrodes, while the non-opening region is optimized for transistor placement with opaque electrodes and wiring. This local differentiation resolves the conflict between light-emitting area and transistor placement.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If high resolution is implemented, then display quality is improved, but the aperture ratio and light-emitting efficiency further deteriorate

Engineering Contradiction:
Improvedisplay resolutionVSAvoidaperture ratio
Core Design Contradiction:
Manufacturing precisionVSArea of stationary object

Solution Approach 1:

The light-emitting diode is designed to extend in multiple dimensions across the sub-pixel, utilizing both the opening and non-opening regions. This dimensional extension allows high resolution to be achieved without sacrificing aperture ratio, as the light emission is distributed across the entire sub-pixel area.

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

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-emitting efficiency by utilizing the previously non-emissive regions for light emission, resulting in improved resolution and display characteristics.

Implementation Method 1

An organic electro-luminescence element used for an organic light-emitting display device is a self-light-emitting element having a light-emitting layer formed between two electrodes positioned on a substrate

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2854179B1Organic light emitting display device
Publication Date: 2023.08.09 LG DISPLAY CO LTD
  • EP2854179B1 patent drawingFigure 1~2
  • EP2854179B1 patent drawingFigure 3(a)~4
  • EP2854179B1 patent drawingFigure 5~6

AI summary

An organic light-emitting display device is disclosed. The organic light emitting display device includes a display panel including sub-pixels (RSP, GSP, BSP) emitting light of at least three colors (R,G,B), and a driver supplying a driving signal to the display panel, wherein each of the sub-pixels emitting at least three colors includes an opening region (EA) emitting its own color and a light-emitting participation region (EA & NEA) additionally emitting the same color as or different color from the its own color.