Stacked Light-Emitting Layers for High Pixel Density

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Solution Overview

Problem

Conventional methods for manufacturing organic light-emitting diode panels face limitations in improving pixel density and resolution due to the size constraints of fine metal masks, which restrict the reduction of sub-pixel size and arrangement variations.

Innovation Solution

A pixel array is created using a manufacturing method that involves multiple stacked light-emitting layers of different colors, where each pixel unit comprises a main and an auxiliary light-emitting layer, allowing for deposition in regions corresponding to multiple sub-pixels, thereby reducing the size of each pixel unit and enhancing pixel density and resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional fine metal mask (FMM) is used to separate different sub-pixels, then sub-pixel separation is achieved, but the opening size is limited to about 30 microns which restricts further improvement of pixel density and resolution

Engineering Contradiction:

Improvepixel density and resolutionVSAvoidmask opening size

Core Design Contradiction:

Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent transitions from planar sub-pixel arrangement to three-dimensional stacked light-emitting layers. Each pixel unit contains multiple sub-pixels arranged vertically in stacks, allowing deposition in regions corresponding to multiple sub-pixels simultaneously. This vertical stacking enables higher pixel density without being constrained by the 30-micron mask opening size limitation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent merges multiple light-emitting layers of different colors into a single pixel unit through vertical stacking. The first, second, and third color light-emitting layers are stacked to form integrated pixel units, allowing multiple sub-pixels to be formed in a compact vertical arrangement rather than requiring separate planar spaces.

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If pixel arrangement is varied to increase pixel density, then some improvement is achieved, but each sub-pixel still remains the same size and the degree of improvement is limited

Engineering Contradiction:

Improvepixel densityVSAvoidpixel arrangement complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Instead of varying pixel arrangements in the planar dimension, the patent introduces vertical stacking as a new dimension. Multiple sub-pixels are arranged in vertical stacks within each pixel unit, dramatically increasing pixel density without requiring complex planar arrangements. The stacked structure includes first, second, and third color light-emitting layers arranged vertically.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Each pixel unit is segmented into multiple stacked light-emitting layers, with each layer corresponding to a different color sub-pixel. This segmentation allows independent optimization of each layer while achieving high overall pixel density. The first color light-emitting layer, second color light-emitting layer, and third color light-emitting layer are distinct segments within each pixel unit.

Inventive Principle:

Principle #1Segmentation

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 enables the production of pixel arrays with higher pixel density and resolution by overcoming the size limitations of traditional sub-pixels, achieving higher light purity and reducing manufacturing costs.

Implementation Method 1

Each of the pixel units comprises at least a first color sub-pixel, a second color sub-pixel and a Nth color sub-pixel... The main light-emitting layer and the auxiliary light-emitting layer are light emitting layers of different color

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

The auxiliary light-emitting layer is stacked on the main light-emitting layer... the main light-emitting layer of the first color sub-pixel and the auxiliary light-emitting layer of the second color sub-pixel are the same material layer

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS10777612B2Pixel array with sub-pixels comprising vertically stacked light emitting layers

Publication Date: 2020.09.15 AU OPTRONICS CORP

AI summary

A pixel array including a plurality of pixel units is provided. Each of the pixel unit includes at least a first color subpixel, a second color subpixel and a Nth color subpixel, wherein N is an integer and N≥3. The first color subpixel includes a first stacked light-emitting layer, the second color subpixel includes a second stacked light-emitting layer, and the Nth color subpixel includes a Nth stacked light-emitting layer. The first stacked light-emitting layer, the second stacked light-emitting layer, and the third stacked light-emitting layer each include a main light-emitting layer and an auxiliary light-emitting layer. The main light-emitting layer of the first color subpixel and the auxiliary light-emitting layer of the second color subpixel are the same material layer. The main light-emitting layer of the Nth color subpixel and the auxiliary light-emitting layer of the first color subpixel are the same material layer.