Repairing Defective White Subpixels in OLED Displays

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Solution Overview

Problem

Active matrix organic light emitting displays face issues with dark spots due to defective circuit units in high transmittance subpixels, which are more visible and require a countermeasure to avoid reducing the aperture ratio.

Innovation Solution

A method that connects the circuit unit of a neighboring subpixel to the light emitting unit of the defective subpixel using a repair conductive pattern, compensating digital video data to prevent dark spots without forming a separate dummy pixel, thus maintaining the aperture ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dummy pixel is formed on the display panel to repair defective pixels, then defective pixels can be removed, but the aperture ratio of the display area is reduced

Engineering Contradiction:
Improvedefect removalVSAvoidaperture ratio
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent makes existing subpixels serve dual functions: normal display function and repair function. By enabling neighboring subpixels to compensate for defective subpixels through data compensation, the display panel can repair defects using existing display area resources, eliminating the need for separate dummy pixels and thus preserving the aperture ratio

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent recovers the functionality of defective subpixels by using data compensation techniques. Instead of discarding the display area to dummy pixels, the system recovers the defective subpixel's function by compensating its data from neighboring subpixels, thereby maintaining both the display area and the ability to repair defects

Inventive Principle:
Principle #34Discarding and recovering

2Illumination intensity

If high transmittance subpixels are used to improve display quality, then image quality is enhanced, but dark spots become more visible when defects occur

Engineering Contradiction:
Improvedisplay qualityVSAvoiddark spot visibility
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback mechanism where the system detects defective subpixels and automatically compensates for them by adjusting the data of neighboring subpixels. This feedback loop ensures that when high transmittance subpixels exhibit defects, the system responds by redistributing their display function to neighboring subpixels, thereby preventing visible dark spots while maintaining high display quality

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent prepares compensation mechanisms in advance for potential defects in high transmittance subpixels. By having the data compensation system ready and the capability to redirect display function to neighboring subpixels before defects become visible, the system cushions against the harmful effect of dark spots while maintaining the benefits of high transmittance subpixels

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2889856B1Method for repairing organic light emitting display
Publication Date: 2024.05.01 LG DISPLAY CO LTD
  • EP2889856B1 patent drawingFigure 1
  • EP2889856B1 patent drawingFigure 2
  • EP2889856B1 patent drawingFigure 3

AI summary

A method for repairing an organic light emitting display having a plurality of unit pixels each including a white subpixel is provided. The method includes detecting a defective white subpixel by checking circuit units of the white subpixels, connecting a circuit unit of a neighboring subpixel positioned adjacent to the defective white subpixel in the unit pixel with a light emitting unit of the defective white subpixel using a repair conductive pattern, storing a repair position to which the repair conductive pattern is connected, and compensating for digital video data that will be input to the repair position.