Positively Charged Insulating Layer Suppresses Drive Current Leakage

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Solution Overview

Problem

Existing display devices with organic electroluminescent elements face challenges in suppressing drive current leakage between adjacent light emitting elements, as previous techniques fail to adequately eliminate highly conductive paths in the organic light emitting layer.

Innovation Solution

Incorporating a positively charged inorganic nitride in at least a part of the film thickness region of an insulating layer between the light emitting elements' electrodes, which prevents the formation of conductive paths by not attracting holes to the interface with the organic light emitting layer, thereby reducing drive current leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a highly conductive layer is used in the organic light emitting layer to improve charge transport, then charge injection and transport efficiency is improved, but drive current leakage between adjacent light emitting elements increases

Engineering Contradiction:

Improvecharge transport efficiencyVSAvoiddrive current leakage suppression

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent applies local quality by creating a charged insulating layer with specific charge distribution between adjacent light emitting elements. The insulating layer is charged to a potential different from adjacent regions, creating localized electrical properties that block current leakage paths while maintaining charge transport within each light emitting element's organic light emitting layer.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The charged insulating layer serves as an intermediary between adjacent light emitting elements. It mediates the electrical interaction by creating a potential barrier that prevents drive current leakage while allowing each light emitting element to maintain its own charge transport functionality through the organic light emitting layer.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the resistance of the highly conductive layer is increased to suppress drive current leakage, then current leakage between adjacent light emitting elements is reduced, but charge transport efficiency deteriorates

Engineering Contradiction:

Improvedrive current leakage suppressionVSAvoidcharge transport efficiency

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent segments the electrical isolation function from the charge transport function. The insulating layer handles electrical isolation between adjacent elements, while the organic light emitting layer maintains its highly conductive properties for charge transport within each element. This segmentation allows both requirements to be satisfied independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The charged insulating layer acts as an intermediary that provides electrical isolation without affecting the charge transport properties of the organic light emitting layer. It creates a potential barrier at the interface, preventing current leakage while allowing efficient charge transport within each light emitting element.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a charged insulating layer is introduced to suppress drive current leakage, then current leakage between adjacent light emitting elements is reduced, but device structure complexity increases

Engineering Contradiction:

Improvedrive current leakage suppressionVSAvoidinsulating layer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the electrical parameter (charge state) of the insulating layer rather than changing its physical structure. By charging the insulating layer to a specific potential, it acquires current-blocking functionality without requiring complex multi-layer structures or additional materials, thus minimizing structural complexity while achieving the desired effect.

Inventive Principle:

Principle #35Parameter changes

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 effectively suppresses drive current leakage between adjacent light emitting elements, enhancing the performance and efficiency of the display device by preventing the formation of conductive paths in the organic light emitting layer.

Implementation Method 1

an insulating layer disposed between the first electrodes, in which at least a part of a film thickness region in the insulating layer contains a positively charged inorganic nitride

Methodology Applied

Scientific EffectElectrostatic repulsion: Electrostatics

Data Source

PatentUS10862070B2Display device and electronic apparatus

Publication Date: 2020.12.08 SONY GROUP CORP

AI summary

There is provided a display device and an electronic apparatus that suppress leakage of a drive current between adjacent light emitting elements. A display device includes a plurality of light emitting elements having an organic light emitting layer sandwiched between a first electrode disposed for each of the light emitting elements and a second electrode in a lamination direction and arrayed on a plane, and an insulating layer disposed between the first electrodes. At least a part of a film thickness region in the insulating layer contains a positively charged inorganic nitride.