Electroluminescence Display Auxiliary Line Structure

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Solution Overview

Problem

Large-sized top-emission type organic light emitting display apparatuses face non-uniform brightness due to high electrical resistance of the common electrode, which increases line resistance and thermal stress, making it difficult to achieve high resolution and integration, especially in displays larger than 55 inches with resolutions above 80 pixels per inch.

Innovation Solution

The implementation of a high-resolution electro-luminescence display apparatus with an optimized auxiliary line structure that reduces line resistance and area of the common line contact unit, improving brightness uniformity and aperture ratio, while also allowing for a narrow bezel and efficient layout of lines within the pixel area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the thickness of the common electrode is reduced to achieve semi-transparent characteristic, then light transmission is improved, but electrical resistance increases

Engineering Contradiction:
Improvelight transmissionVSAvoidelectrical resistance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The common electrode uses a composite structure of multiple thin metal layers (e.g., Al/LiF/Al or Mo/Al/Mo) instead of a single thick layer. This composite structure maintains semi-transparent properties while achieving lower electrical resistance through synergistic material properties and optimized layer configurations.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the thickness parameters of each layer in the composite common electrode to achieve the right balance between transparency and conductivity. By precisely controlling layer thicknesses in the range of tens to hundreds of angstroms, the electrode achieves both semi-transparent characteristic and acceptable electrical resistance.

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If the distance from the cathode voltage supply unit to the common electrode increases to achieve larger display size, then display area is improved, but brightness uniformity deteriorates due to high line resistance

Engineering Contradiction:
Improvedisplay areaVSAvoidbrightness uniformity
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The common electrode is divided into multiple segments or regions, each independently connected to the cathode voltage supply unit through separate cathode lines. This segmentation reduces the length of each cathode line, thereby reducing line resistance and improving brightness uniformity across large display areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces additional cathode lines or voltage supply paths in multiple directions (e.g., both horizontal and vertical cathode lines forming a grid), creating redundant voltage supply routes. This multi-dimensional approach reduces the effective resistance by providing multiple parallel paths for current flow.

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

3Area of stationary object

If the area of the common line contact unit is reduced to improve aperture ratio, then pixel area is improved, but manufacturing precision becomes more difficult

Engineering Contradiction:
Improveaperture ratioVSAvoidalignment precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The common line contact unit is pre-formed or pre-positioned during earlier manufacturing steps, establishing a fixed reference structure before subsequent alignment-critical steps. This preliminary action provides a stable baseline that simplifies subsequent alignment processes and reduces precision requirements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces intermediary structures or alignment marks that facilitate precise positioning of the common line contact unit. These intermediary elements act as mediators during the manufacturing process, enabling accurate alignment even with reduced contact unit area through optical or mechanical reference systems.

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

The solution effectively reduces line resistance variations, enhances brightness uniformity, and supports high-resolution displays by optimizing the layout of common, anode, gate, and data lines, enabling the production of high-brightness and high-dynamic-range displays with improved thermal management.

Implementation Method 1

Each of the sub-pixels includes an organic light emitting diode (OLED)... an organic emission layer... capable of emitting light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3369114B1Electro-luminescence display apparatus
Publication Date: 2023.03.15 LG DISPLAY CO LTD
  • EP3369114B1 patent drawingFigure 1
  • EP3369114B1 patent drawingFigure 2
  • EP3369114B1 patent drawingFigure 3

AI summary

An electroluminescence display apparatus comprising: a plurality of sub-pixel circuit units arranged in a matrix form; at least one gate line disposed between the plurality of sub-pixel circuit units and extending along a first direction; a plurality of first data line groups and a plurality of second data line groups alternatively disposed between the plurality of sub-pixels circuit units and extending along a second direction; a plurality of common lines disposed within the first or the second data line groups and extending along the second direction; and a plurality of anode lines disposed within the first or the second data line groups and extending along the second direction.