OLED Sub-Pixel Structure with Electron Accepting Layer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Organic light-emitting display apparatuses face challenges in achieving low driving voltage and improved image quality and lifetime due to surplus electrons causing thermal degradation and color mixture, especially when using blue organic emission layers in all sub-pixels.

Innovation Solution

The apparatus includes a substrate with a first and second electrode, an organic emission layer comprising red, green, and blue sub-pixels, and an electron accepting layer that traps surplus electrons, reducing thermal degradation and color mixture by positioning the blue organic emission layer as a common layer across all sub-pixels, thereby improving the structure's efficiency and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a blue organic emission layer is commonly used in all sub-pixels, then the manufacturing process is simplified, but color mixture occurs and image quality deteriorates

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidimage quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The organic emission layer is segmented into sub-pixel-specific emission layers (red, green, blue) positioned in respective sub-pixel regions, with a separate common blue emission layer positioned in the common region. This segmentation prevents color mixture while maintaining manufacturing simplicity through the common blue layer approach.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the display are assigned different emission layer configurations: sub-pixel regions have their specific color emission layers, while the common region has a blue emission layer. This local differentiation resolves the color mixture issue in sub-pixels while utilizing the common blue layer for efficiency.

Inventive Principle:

Principle #3Local quality

2Productivity

If the thickness of organic emission layer is increased to improve transfer efficiency in LITI process, then more energy is consumed, but thermal degradation of organic materials occurs

Engineering Contradiction:

Improvetransfer efficiencyVSAvoidthermal degradation

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

Instead of increasing thickness in the vertical dimension to improve transfer efficiency, the patent introduces a horizontal dimension by adding a common blue emission layer in the common region. This dimensional shift allows efficient electron utilization without excessive thickness that would cause thermal degradation.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If surplus electrons are allowed to move toward hole injection layer or hole transport layer, then the device structure is simpler, but light efficiency deteriorates and device lifetime is reduced

Engineering Contradiction:

Improvedevice structureVSAvoiddevice lifetime

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The common blue emission layer acts as an intermediary that captures and utilizes surplus electrons before they can reach the hole injection layer or hole transport layer. This intermediary structure improves device lifetime and light efficiency by preventing harmful electron accumulation while adding minimal structural complexity.

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

This configuration reduces surplus electron impact, enhancing the display's image quality and extending its lifetime while maintaining low driving voltage and efficient energy use.

Implementation Method 1

an electron accepting layer which is disposed between the first electrode and the second electrode so as to contact the organic emission layer

Methodology Applied

Scientific EffectElectron capture: Absorption (physical)

Implementation Method 2

laser beams then irradiate the donor film, thereby completing the patterning process

Methodology Applied

Scientific EffectLaser induced thermal imaging: Laser

Implementation Method 3

a donor film including a light-to-heat conversion layer (LTHC) and a transfer layer

Methodology Applied

Scientific EffectLight-to-heat conversion: Absorption (EM radiation)

Implementation Method 4

when a voltage is applied to the cathode and the anode, the organic emission layer connected to the cathode and the anode emits visible light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS9006713B2Organic light-emitting display apparatus

Publication Date: 2015.04.14 SAMSUNG DISPLAY CO LTD

AI summary

In one aspect, an organic light-emitting display apparatus is provided including a first sub-pixel, a second sub-pixel, and a third sub-pixel that are each a different color, the apparatus including: a substrate; a first electrode disposed on the substrate; a second electrode disposed on the first electrode so as to face the first electrode; an organic emission layer disposed between the first electrode and the second electrode and comprising a first organic emission layer, a second organic emission layer, and a third organic emission layer; a hole transport layer disposed between the first electrode and the organic emission layer; and an electron accepting layer disposed between the first electrode and the second electrode. The organic light-emitting display apparatus has improved image quality and lifetime.