OLED Pixel Oblique Sub-pixel Layout for Blue Degradation

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Solution Overview

Problem

Active matrix OLED display panels face significant color casts and reduced service life due to high degradation rates of blue sub-pixels, which affects the overall service life and aperture ratio of the display panel.

Innovation Solution

The arrangement of red, green, and blue sub-pixels in an oblique configuration with the blue sub-pixel being the longest, maintaining the same width as the others, increases the opening area of the blue sub-pixel, reducing current density and degradation rate without reducing the total aperture ratio, thereby prolonging the service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the blue sub-pixel is made longer to increase its opening area and reduce current density, then the service life is improved, but the pixel layout complexity increases

Engineering Contradiction:
Improveservice lifeVSAvoidpixel layout complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by making the blue sub-pixel longer than the red and green sub-pixels. This asymmetric design increases the opening area of the blue sub-pixel, thereby reducing current density and degradation rate, which directly improves service life while accepting increased layout complexity as a necessary trade-off

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by giving the blue sub-pixel different dimensions (longer length) compared to the red and green sub-pixels. This localized modification targets the specific problem of blue sub-pixel degradation by adjusting only the blue sub-pixel's geometry to reduce its current density, while maintaining standard dimensions for other sub-pixels

Inventive Principle:
Principle #3Local quality

2Reliability

If the blue sub-pixel opening area is increased to reduce current density, then the degradation rate is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvedegradation rateVSAvoidsub-pixel dimension precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The asymmetric design of the blue sub-pixel with greater length creates a larger opening area that naturally reduces current density. This geometric modification addresses the degradation rate issue while the precision requirements are managed through standard fabrication processes applied to the asymmetric pattern

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the geometric parameters of the blue sub-pixel by increasing its length dimension. This parameter modification increases the opening area and reduces current density, thereby lowering the degradation rate. The manufacturing precision is maintained within acceptable ranges for display fabrication

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 configuration effectively prolongs the service life of the display panel by reducing blue sub-pixel degradation while maintaining the total aperture ratio, enhancing display quality and reducing energy consumption.

Implementation Method 1

The organic light emitting layer is driven by an applied electric field and gives rise to a luminescence phenomenon through injection and recombination of carriers from the anode and the cathode respectively

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3125327B1Organic light-emitting diode display pixel, display panel and display device
Publication Date: 2021.02.17 BOE TECHNOLOGY GROUP CO LTD
  • EP3125327B1 patent drawingFigure 1
  • EP3125327B1 patent drawingFigure 2
  • EP3125327B1 patent drawingFigure 3

AI summary

An organic light emitting diode display pixel (100), a display panel and a display device are provided. The organic light emitting diode display pixel (100) comprises a red light emitting device (10), a green light emitting device (20) and a blue light emitting device (30) arranged side by side and disposed oblique with respect to a border of the pixel. The red light emitting device (10) and the green light emitting device (20) are located on both sides of the blue light emitting device (30), which has a length larger than those of the red one (10) and the green one (20). The display pixel can prolong the service life of a display panel without reducing the total aperture ratio of pixels.