OLED Subpixel Leakage Control via Local Separation Structures

Solution Overview

Problem

Existing organic light-emitting diode (OLED) display apparatuses face challenges in reducing leakage current between subpixels while maintaining light emission efficiency, as structures to limit leakage current can decrease luminance and emission efficiency if applied universally.

Innovation Solution

The display apparatus incorporates a separation structure between specific subpixels with higher leakage current, limiting current leakage between subpixels with larger driving current differences, thereby maintaining effective area and emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If structures are provided in all boundary portions between subpixels to limit leakage current, then current leakage between subpixels is reduced, but light emission amounts of individual subpixels decrease and light emission efficiency or luminance lowers

Engineering Contradiction:

Improvecurrent leakage reductionVSAvoidluminance

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent applies local quality by providing separation structures only at specific boundary portions between subpixels where leakage current is significant, rather than uniformly across all boundaries. The separation structure includes an insulating layer and a conductive layer selectively positioned between subpixels with larger driving current differences, thereby locally addressing leakage issues without compromising the overall light emission efficiency and luminance of the display apparatus.

Inventive Principle:

Principle #3Local quality

2Reliability

If structures are provided in all boundary portions between subpixels to limit leakage current, then current leakage between subpixels is reduced, but light emission efficiency decreases

Engineering Contradiction:

Improvecurrent leakage reductionVSAvoidlight emission efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by providing separation structures only at specific boundary portions between subpixels where leakage current is significant, rather than uniformly across all boundaries. The separation structure includes an insulating layer and a conductive layer selectively positioned between subpixels with larger driving current differences, thereby locally addressing leakage issues without compromising the overall light emission efficiency and luminance of the display apparatus.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If separation structures are selectively provided between specific subpixels, then light emission efficiency is maintained, but current leakage between subpixels with larger driving current differences may persist

Engineering Contradiction:

Improvelight emission efficiencyVSAvoidcurrent leakage control

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent applies parameter changes by selectively adjusting the driving current parameters of different subpixels and providing separation structures based on the magnitude of current differences. The insulating layer and conductive layer are positioned between subpixels where the driving current difference exceeds a threshold, dynamically addressing leakage current control while preserving light emission efficiency in other regions.

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 reduces leakage current between subpixels with larger driving current differences while preserving light emission efficiency, preventing unwanted color shifts and maintaining high luminance.

Implementation Method 1

each pixel is provided with a plurality of subpixels configured to generate light components of colors different from each other such as blue light, green light, and red light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS11521536B2Display apparatus and electric apparatus with controlled current leakage among subpixels

Publication Date: 2022.12.06 CANON KK

AI summary

A display apparatus comprising a pixel provided on a substrate, the pixel including a first subpixel, a second subpixel, and a third subpixel which are arranged to be adjacent to each other and are configured to generate light components of colors different from each other, and the first, second and third subpixels comprise an organic compound layer including a light emission layer, wherein letting I1, I2, and I3 be driving current amounts of the first, second and third subpixels when generating white light of a predetermined luminance, if I1>I2>I3 holds, a current leakage between the first and third subpixels is limited as compared to that between the second and third subpixels.