OLED Pixel Electrode Symmetry for Viewing Angle Color Shift

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Solution Overview

Problem

Organic light emitting diode (OLED) display devices experience viewing angle-dependent color shift due to asymmetrical or non-uniform lower portions of pixel electrodes, leading to color changes when viewed from different directions.

Innovation Solution

A method of manufacturing OLED display devices involves forming a photosensitive material layer on a substrate, creating a first protective layer with a recess and contact holes, and a conductive line within the recess, followed by a second protective layer and electrodes, ensuring the first electrode overlaps the recess and is symmetrically disposed relative to the conductive line, which helps in reducing azimuth angle-dependent color deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a multilayer structure including OLED is used to achieve self-luminous display with low power consumption and high luminance, then power consumption is reduced and luminance is improved, but viewing angle-dependent color shift occurs due to asymmetrical pixel electrode lower portions

Engineering Contradiction:
ImproveluminanceVSAvoidcolor uniformity
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent intentionally introduces asymmetry through the recess structure in the lower protective layer to compensate for the inherent asymmetry in pixel electrode lower portions. The recess is positioned and dimensioned specifically to create a symmetrical optical path when viewed from different angles, thereby correcting the viewing angle-dependent color shift while preserving the multilayer OLED structure's luminance advantages

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If the first electrode is positioned to overlap the recess and disposed symmetrically relative to the conductive line, then color deviations are minimized across viewing angles, but the manufacturing process complexity increases

Engineering Contradiction:
Improvecolor consistencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The recess structure is formed in advance during the protective layer formation process, before the first electrode is deposited. This preliminary action establishes the correct geometric relationship and symmetry axis early in manufacturing, guiding subsequent electrode positioning and ensuring color consistency without requiring complex real-time adjustments during later fabrication steps

Inventive Principle:
Principle #10Preliminary action

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

The solution effectively minimizes color deviations when viewed from different angles, enhancing the display characteristics of OLED devices by maintaining consistent color recognition across various viewing directions.

Implementation Method 1

forming a photosensitive material layer on a substrate by applying a photosensitive material onto the substrate. A first protective layer is formed on the substrate by patterning the photosensitive material layer

Methodology Applied
Scientific EffectPhotolithography: Photopolymerisation

Data Source

PatentEP3331021B1Organic light emitting diode display device
Publication Date: 2025.01.01 SAMSUNG DISPLAY CO LTD
  • EP3331021B1 patent drawingFigure 1
  • EP3331021B1 patent drawingFigure 2
  • EP3331021B1 patent drawingFigure 3~4

AI summary

An organic light emitting diode display device includes a substrate. A first protective layer is disposed on the substrate. A conductive line is disposed on the first protective layer. A second protective layer is disposed on the conductive line. A first electrode is disposed on the second protective layer. An organic light emitting layer is disposed on the first electrode. A second electrode is disposed on the light emitting layer. The first electrode is symmetric with respect to a center of the conductive line.