Pixel Electrode Layout for OLED Brightness

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Solution Overview

Problem

Organic light-emitting display apparatuses face reduced brightness due to smaller sub-pixel sizes, which affect image precision and overall display quality.

Innovation Solution

The design includes adjacent pixel electrodes with a pixel-defining layer that covers parts of each electrode except the center and edges facing adjacent electrodes, allowing increased light emission areas without expanding the electrode size, and thin film transistors connected to these electrodes with an insulating layer covering the connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the size of sub-pixels is reduced to achieve high resolution, then the resolution is improved, but the brightness is reduced

Engineering Contradiction:
ImproveresolutionVSAvoidbrightness
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The pixel-defining layer is divided into multiple regions with different coverage patterns: it covers the connecting portions of pixel electrodes to TFTs, covers three edges of each pixel electrode, but leaves the center portion and one edge (facing adjacent pixel electrode) exposed. This segmented coverage strategy maximizes the light emission area while maintaining proper electrical connections and pixel isolation, thereby improving brightness without sacrificing resolution

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent optimizes the light emission area by strategically exposing specific portions (center and one edge) of the pixel electrode in the planar dimension, rather than increasing the overall pixel size. This dimensional optimization allows more light emission regions within the constrained sub-pixel area, addressing the brightness reduction issue while maintaining high resolution

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

2Reliability

If the pixel-defining layer covers the connecting portion of pixel electrode to TFT, then the electrical connection is protected, but the light emission area is reduced

Engineering Contradiction:
Improveelectrical connectionVSAvoidbrightness
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The pixel-defining layer applies selective coverage: it covers the connecting portions of pixel electrodes to TFTs to ensure reliable electrical connections, while simultaneously leaving the center portion and the edge facing the adjacent pixel electrode uncovered to maximize light emission. This local differentiation resolves the contradiction by providing protection where needed and light emission where beneficial

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 brightness and image precision by increasing the light emission area while maintaining the limited size of sub-pixel electrodes, improving the overall display quality and brightness of the organic light-emitting display apparatus.

Implementation Method 1

an organic light-emitting display apparatus displaying images by using light emitted from an emission layer disposed between a pixel electrode and an opposite electrode

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3089215B1Organic light-emitting display apparatus
Publication Date: 2020.10.28 SAMSUNG DISPLAY CO LTD
  • EP3089215B1 patent drawingFigure 1
  • EP3089215B1 patent drawingFigure 2
  • EP3089215B1 patent drawingFigure 3

AI summary

An organic light-emitting display apparatus includes a first pixel electrode (311) and a second pixel electrode (312) that are disposed spaced apart adjacent to each other; and a pixel-defining layer (219) disposed on the first pixel electrode (311) and the second pixel electrode (312), the pixel-defining layer (219) covering a part of the first pixel electrode (311) and a part of the second pixel (313) electrode except a center portion of the first pixel electrode (311), a center portion of the second pixel electrode (312), a first edge of the first pixel electrode (311) in a direction toward the second pixel electrode (312), and a second edge of the second pixel electrode (312) in a direction toward the first pixel electrode (311).