OLED Charge Generating Layer Segmentation Between Adjacent Pixels

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Solution Overview

Problem

Light emitting display panels face issues with undesired light emission due to leakage currents between adjacent pixels, caused by a continuously provided charge generating layer.

Innovation Solution

The charge generating layer is separated between pixels by forming a first main charge generating layer on the surface of the light emitting unit and a first sub charge generating layer on the bank, with the main charge generating layer being separated from the sub charge generating layer at the end of the light emitting unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the charge generating layer is continuously provided in adjacent pixels, then the light emitting display panel can be manufactured with simpler process, but leakage current occurs between adjacent pixels causing undesired light emission

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidleakage current

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The charge generating layer is divided into multiple separate regions corresponding to individual pixels, with insulating layers positioned between adjacent pixel regions. This segmentation prevents charge carrier migration between pixels while maintaining the charge generating functionality within each pixel, thereby eliminating leakage current without significantly complicating the manufacturing process.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the charge generating layer is continuously provided in adjacent pixels, then the device structure can be simplified, but undesired light emission occurs due to leakage current

Engineering Contradiction:

Improvestructure simplicityVSAvoidundesired light emission

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The charge generating layer is segmented into discrete regions for each pixel, separated by insulating layers. This segmentation eliminates the continuous path for charge carriers between pixels, preventing leakage current and the resulting undesired light emission, while adding only minimal structural complexity through the insertion of thin insulating barrier layers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Insulating layers are introduced as intermediary elements between adjacent charge generating layer regions. These insulating layers act as barriers that prevent charge carrier migration between pixels while allowing each pixel's charge generating layer to function independently, thereby eliminating leakage current without requiring complete restructuring of the device.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the charge generating layer is continuously provided, then fewer manufacturing steps are required, but leakage current between pixels increases

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidleakage current prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The charge generating layer is segmented into pixel-specific regions separated by insulating layers. This segmentation can be integrated into existing manufacturing processes through standard photolithography and deposition techniques, adding minimal steps while effectively preventing leakage current and improving device reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Insulating layers are formed preliminarily between charge generating layer regions during the manufacturing process, creating built-in barriers that prevent leakage current from the outset. This preliminary action ensures reliable pixel isolation is established before subsequent processing steps, preventing leakage current issues in the final device.

Inventive Principle:

Principle #10Preliminary action

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 separation effectively reduces leakage currents between pixels, enhancing the display's efficiency and reducing unwanted light emission, thereby improving the overall performance of the light emitting display apparatus.

Implementation Method 1

a first charge generating layer provided in an upper surface of the first main light emitting unit and in an upper surface of a bank exposed between the first anode and the second anode... the first main charge generating layer is separated from the first sub charge generating layer at an end of the first main light emitting unit

Methodology Applied

Scientific EffectCharge carrier generation and separation:

Data Source

PatentUS20230317884A1Light emitting display apparatus and method of manufacturing the same

Publication Date: 2023.10.05 LG DISPLAY CO LTD

AI summary

A light emitting display apparatus in which a charge generating layer is separated between pixels, and a method using the same are discussed. The light emitting display apparatus can include a first anode and a second anode provided on a substrate, a bank provided on the first anode and the second anode and including at least one opening portion at which the first anode and the second anode are exposed, a first light emitting unit including a first main light emitting unit provided on the first anode, a first charge generating layer provided in an upper surface of the first main light emitting unit and in an upper surface of a bank exposed between the first anode and the second anode, an additional light emitting layer covering the first charge generating layer, and a cathode covering the additional light emitting layer.