OLED Subpixel Luminance Control for Lifetime Extension

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Solution Overview

Problem

Existing OLED displays face challenges in maintaining color balance and extending the lifetime due to differential aging of red, green, and blue subpixels, which affects luminance and power consumption, as current density increases with luminance, leading to uneven degradation and color shifts.

Innovation Solution

A method that adjusts the intensity values of colored subpixels based on color saturation, particularly reducing the current and luminance of subpixels with shorter lifetimes, such as blue, to extend their lifespan and maintain color balance, while minimizing power consumption and hue shifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If current density is increased to increase luminance, then luminance is improved, but OLED lifetime is reduced and power consumption increases

Engineering Contradiction:
ImproveluminanceVSAvoidOLED lifetime
Core Design Contradiction:
Illumination intensityVSDuration of action of stationary object

Solution Approach 1:

The patent applies different luminance reduction strategies to different color subpixels based on their individual lifetime characteristics. Blue subpixels, which have shorter lifetimes, receive greater luminance reduction through saturation-based dimming compared to red or green subpixels. This localized differential treatment extends the overall display lifetime by protecting the most vulnerable components without unnecessarily reducing luminance of more durable subpixels.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If current density is increased to increase luminance, then luminance is improved, but power consumption increases

Engineering Contradiction:
ImproveluminanceVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent implements partial luminance reduction only when color saturation exceeds a threshold, rather than uniformly reducing all luminance. This selective approach maintains full luminance for unsaturated or low-saturation content while applying dimming only when necessary to extend lifetime, thereby minimizing the impact on power consumption and perceived image quality.

Inventive Principle:
Principle #16Partial or excessive action

3Duration of action of stationary object

If luminance of saturated colors is reduced to extend lifetime, then OLED lifetime is improved, but image quality may be impacted

Engineering Contradiction:
ImproveOLED lifetimeVSAvoidimage quality
Core Design Contradiction:
Duration of action of stationary objectVSManufacturing precision

Solution Approach 1:

The patent selectively applies luminance reduction based on color saturation characteristics. By identifying highly saturated colors (particularly blue) and reducing their luminance while maintaining luminance for unsaturated colors, the system extends OLED lifetime without creating noticeable image quality degradation, as unsaturated content maintains full brightness and saturated content reduction is applied only when beneficial.

Inventive Principle:
Principle #32Color changes

Data Source

PatentEP2321818B1Method for improving display lifetime
Publication Date: 2013.04.17 GLOBAL OLED TECHNOLOGY LLC
  • EP2321818B1 patent drawingFigure 1
  • EP2321818B1 patent drawingFigure 2
  • EP2321818B1 patent drawing

AI summary

A method for adjusting the intensity values of colored pixels wherein each pixel has a first subpixel, a second subpixel, and a third subpixel, wherein each of the subpixels emits light of a different color and the lifetime of the first subpixel is lower than the lifetimes of the other colored subpixels, comprising: for each pixel, receiving intensity values corresponding to the intensity of each color subpixel in each pixel; and lowering the intensity value of the first subpixel in each pixel and still providing an acceptable pixel color to an observer.